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PICCIRILLO, Gianfranco, Giuseppe GERMANÒ, Raffaele QUAGLIONE, Marialuce NOCCO, Filippo LINTAS, Marco LIONETTI, Antonio MOISÈ, Maddalena RAGAZZO, Vincenzo MARIGLIANO e Mauro CACCIAFESTA. "QT-interval variability and autonomic control in hypertensive subjects with left ventricular hypertrophy". Clinical Science 102, n.º 3 (14 de fevereiro de 2002): 363–71. http://dx.doi.org/10.1042/cs1020363.
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Left ventricular hypertrophy is a risk factor for sudden death. Malignant ventricular arrhythmias originate from altered cardiac repolarization. Ample data have described spatial abnormalities in cardiac repolarization [QT interval (QT) dispersion] in subjects with hypertension; more data are needed on temporal changes. This study was designed to assess the QT variability index (QTVI), the slope between QT and the RR interval (QT-RRslope) and spectral QT variability in subjects with arterial hypertension. The results were compared with those from a population at high risk of sudden death, i.e. patients with hypertrophic cardiomyopathy (HCM) who had received an implantable cardioverter/defibrillator (ICD), and those from normotensive control subjects. A total of 44 hypertensive subjects, six patients with HCM and an ICD and 33 control subjects underwent simultaneous short-term recording (256 beats) of QT, RR and systolic blood pressure variability, in the supine position, during controlled breathing. QTVI and spectral components of QT variability in the hypertensive group were significantly higher than in normotensive control subjects (P < 0.001), but significantly lower than in patients with HCM and an ICD (P < 0.001). The severity of left ventricular hypertrophy correlated significantly with QTVI and the ratio of low-frequency (LF) to high-frequency (HF) power obtained from the RR variability spectra (RRLF/HF, slope = 0.24, P < 0.05; QTVI, slope = 4.06, P < 0.0001; intercept, slope = 2.40, P < 0.05; χ2 = 38.8; P < 0.0001). The QT-RR slope was significantly higher only in patients with HCM and an ICD (P < 0.001). In conclusion, the increased QTVI and the correlation of this index with left ventricular hypertrophy indicates that hypertension increases temporal cardiac repolarization abnormalities. At the level of the cardiac sinus node, this alteration is associated with increased sympathetic and reduced vagal modulation. As already noted in patients with HCM, the increased QTVI could be a factor responsible for triggering malignant ventricular arrhythmias in subjects with hypertension.
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Laiche, Adolph J. "Effects of Rate and Repeat Application of Flurprimidol on the Growth of Photinia × fraseri and Ilex crenata ‘Compacta’". Journal of Environmental Horticulture 6, n.º 4 (1 de dezembro de 1988): 114–18. http://dx.doi.org/10.24266/0738-2898-6.4.114.
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Flurprimidol, α-(1-Methylethyl)-α-[4-(trifluoromethoxy)phenyl]-5-pyrimidine-methanol, was applied to three month plants of Photinia × fraseri in 5.6 L (6 qt) containers and Ilex crenata ‘Compacta’ in 2.8 L (3 qt) containers as foliar sprays at 0, 33, 66, 132, 264, 528, 1056, 2112, 4224, and 8448 ppnl. Growth-medium drench applications with flurprimidol were applied at 0, 2, 4, 8, 16, 32, 64, 128, 256, and 512 ppm solution, 0.5 L (17 oz) per 5.6 L (6 qt) container to Photinia. The initial foliar spray treatments and the growth medium drench treatments were applied on July 14, 1983. All test plants were planted in soil on December 9, 1983. Foliar spray treatments were repeated on July 19, 1985. Flurprimidol at low concentrations as a spray and drench substantially reduced plant size with little or no phytotoxicity. Duration of growth suppression increased as rate increased. Flurprimidol at low rates reduced growth for the remainder of the growing season in which it was applied. At higher rates growth was also reduced in the following growing season. Minor leaf distortion of smaller leaves was obtained at low rates and leaf distortion appeared to increase slightly at higher rates. Shoot growth after the effects of flurprimidol were no longer apparent appeared normal. Results indicate that flurprimidol alone and in conjunction with pruning can be helpful in maintaining woody landscape plants to a desirable size.
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Schulman, L. L., e Y. Enson. "Role of cyclooxygenase inhibition and hyperoxia in regulating pulmonary perfusion in dogs". American Journal of Physiology-Heart and Circulatory Physiology 268, n.º 4 (1 de abril de 1995): H1521—H1530. http://dx.doi.org/10.1152/ajpheart.1995.268.4.h1521.
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To assess the roles of cyclooxygenase inhibition and hyperoxia in regulating pulmonary perfusion, we studied 13 dogs with diffuse granulomatous lung disease (DGLD) and 13 normal dogs. Baseline observations were obtained at fractional inspired O2 (FIO2) 0.21 and 1.0 and repeated after infusion of meclofenamate (Mec; n = 8) or saline (n = 5). Resistance to flow was evaluated from the pulmonary end-diastolic gradient (PDG) and by ohmic pulmonary vascular resistance (PVR). Distribution of blood flow was evaluated with sulfur hexafluoride in DGLD and with multiple inert gas alveolar ventilation-perfusion (VA/Q) plots in normal dogs. Before infusion, there were no differences between the saline and Mec groups at either FIO2. Saline induced no significant changes at either FIO2. After Mec in DGLD, PDG at FIO2 0.21 rose from 4 +/- 2 to 6 +/- 4 mmHg (P < 0.04), PVR increased from 297 +/- 98 to 484 +/- 181 dyn.s.cm-5.m-2 (P < 0.01), whereas shunt flow (Qs/Qt) fell form 13.6 +/- 12.0 to 6.2 +/- 5.3% (P < 0.03). At FIO2 1.0 PDG rose from 3 +/- 2 to 4 +/- 3 mmHg (P < 0.02), PVR increased from 262 +/- 78 to 374 +/- 139 dyn.s.cm-5.m-2 (P < 0.01), whereas Qs/Qt fell from 14.5 +/- 13.3 to 6.4 +/- 5.2% (P < 0.02). After Mec in normal dogs, PDG at FIO2 0.21 rose from 3 +/- 1 to 4 +/- 1 mmHg (P < 0.015) and PVR increased from 256 +/- 92 to 340 +/- 101 dyn.s.cm-5.m-2 (P < 0.05); at FIO2 1.0 PDG and PVR were unchanged from preinfusion levels. In normal dogs, no parameters of VA/Q changed significantly with hyperoxia or Mec. These data suggest that perivascular inflammation enhances perfusion in DGLD by elaboration of vasodilator prostaglandins (PG). By inhibiting PG synthesis, Mec selectively increases resistance in diseased lung at FIO2 0.21 and lowers Qs/Qt. In contrast, there was vasoconstriction without flow redistribution in normal dogs, suggesting that vasodilator PGs contribute to the low tone in the normal pulmonary bed. The vasodilation without flow redistribution in both models during hyperoxia after Mec suggests an effect of O2 that is related neither to PG synthesis nor to hypoxic vasoconstriction.
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Herrero-Morant, A., J. Zubiaur-Zamacola, A. Margarida-de Castro, R. Pérez-Barquín e R. Blanco. "POS1148 OPTIMAL CUT-OFF POINT FOR ELECTROCARDIOGRAM IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS ON HYDROXYCHLOROQUINE THERAPY". Annals of the Rheumatic Diseases 82, Suppl 1 (30 de maio de 2023): 904. http://dx.doi.org/10.1136/annrheumdis-2023-eular.4462.
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BackgroundHydroxychloroquine (HCQ) is a widely used drug in Systemic Lupus Erythematosus (SLE) that can cause cardiac alterations such as arrhythmic events in the short-term and dose-dependent cardiomyopathy in the medium to long-term. The cardiological implications of HCQ accumulation in these patients in the medium to long-term is unknown.ObjectivesTo assess the optimal cut-off point for electrocardiogram (ECG) in patients with SLE on HCQ therapy to prevent arrhythmic complications.MethodsSingle university hospital observational study of all consecutive SLE patients who had an ECG at baseline and at least one ECG at follow-up. New conduction disturbances were assessed by ECG, defined as atrioventricular block, bundle branch block or QT interval prolongation. ECGs were extracted from the medical record and interpreted at baseline and for 15.2 years (95%CI 13.24-17.16) of follow-up. We defined cumulative HCQ (cHCQ) as the total grams of HCQ that had been administered. A Receiver Operating Characteristic (ROC) curve analysis was performed to determine the optimal cut-off point for sensitivity and specificity.ResultsWe studied 105 (93 female/12 male) SLE patients with a mean (±SD) age of 61.8±14.9 years. The mean daily dose of HCQ in our sample was 256 mg per day (Table 1). The ROC curve showed a moderate diagnostic ability for new conduction disturbances with an area under the curve of 0.69 (95% CI 0.59 - 0.77) (Figure 1). The highest efficacy cut-off point was cHCQ: 4097g (Sensitivity 15%; Specificity 100%) and the optimal cut-off point was cHCQ: 901g (Sensitivity 85%; Specificity 52.9%). This cut-off point was reached with a mean HCQ treatment in our sample of 9.7 years. High grade atrio-ventricular block was found in 5 patients. In all of them the cHCQ dose was over 901g.ConclusionAccording to our study, 901g of cHCQ dose is a good cut-off point for performing a protocolized ECG to rule out cardiac conduction disturbances in patients with SLE and chronic HCQ treatment. This is equivalent to 9.7 years of treatment with the mean HCQ dose use in our sample.Table 1.Clinical characteristics of Systemic Lupus Erythematosus patientsGeneral characteristicsGlobal (N=105)Current age (mean ± SD)61.8 ± 14.9Years of SLE evolution (mean ± SD)16.3 ± 10.3Sex, n (%)93 (88.6)Diabetes Mellitus, n (%)15 (14.4)Hypertension, n (%)58 (55.2)Dyslipidaemia, n (%)47 (45.2)Chronic renal failure, n (%)10 (9.6)Obesity, n (%)8 (7.8)Alcohol consumption, n (%)3 (2.9)Smoking history, n (%)41 (39.0)SLE treatmentHCQ dose in mg/day (mean ± SD)256 ± 87.2Time in HCQ in months (mean ± SD)149.8 ± 111.9Cumulative HCQ dose in grams (mean ± SD)1154.94 ± 946.10Cumulative HCQ dose in grams, median (IQR)913.1 (474, 1473)Prednisone, n (%)30 (28.6)Prednisone dose in mg/day (mean ± SD)17.3 ± 16.8Other immunosuppressant, n (%)14 (13.3)Abbreviations:HCQ: Hydroxychloroquine, SLE: Systemic Lupus ErythematosusFigure 1.Receiver Operating Characteristic (ROC) curve on cumulative hydroxychloroquine dose and new conduction disturbancesREFERENCES:NIL.Acknowledgements:NIL.Disclosure of InterestsAlba Herrero-Morant: None declared, Jon Zubiaur-Zamacola: None declared, Adrián Margarida-de Castro: None declared, Raquel Pérez-Barquín: None declared, Ricardo Blanco Speakers bureau: Abbvie, Pfizer, Roche, Lilly, Bristol-Myers, Janssen, Galapagos and MSD, Consultant of: Abbvie, Pfizer, Roche, Lilly, Bristol-Myers, Janssen and MSD, Grant/research support from: Abbvie, MSD, Novartis and Roche.
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Yuan, Xiaoguang, Yida Yang, Weifeng Li e Chengshan Wang. "Provenance of Triassic Xiazijie Fan-Delta in Junggar Basin, Northwestern China: Insights from U-Pb Dating of Detrital Zircons". Minerals 13, n.º 4 (26 de março de 2023): 467. http://dx.doi.org/10.3390/min13040467.
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Abundant hydrocarbon resources were discovered in the Xiazijie fan-delta in the Triassic Baikouquan Formation in Mahu sag, Junggar basin. However, the maximum depositional age of Baikouquan Formation and provenance of this fan-delta are still unclear, which would be unfavourable for further hydrocarbon exploration. In this study, we used detrital zircon U-Pb dating and composition statistics of conglomerate clast and sandstone grain from Baikouquan Formation to constrain the maximum depositional age and provenance of the Xiazijie fan-delta. The results showed that (1) the conglomerate clast compositions of Xiazijie fan-delta mainly consisted of tuff and intermediate-felsic magmatic rocks, and sandstone samples could be classified as litharenite type with the lithic fragments were almost entirely volcanic lithic fragments; (2) the average Qt:F:L values of sandstone samples (M152-S1 and M152-S2) were 26:7:67 and 21:8:71, respectively, and they plotted in the magmatic arc domain in the Qt-F-L ternary diagram, indicating the tectonic setting of source area of Xiazijie fan-delta was magmatic arc; (3) M152-S1 yielded U-Pb ages ranging from 417 Ma to 253 Ma, with a dominant age peak at 313 Ma and two secondary age peaks at 411 Ma and 268 Ma, respectively, while M152-S2 yielded U-Pb ages ranging from 467 Ma to 256 Ma, with a dominant age peak at 307 Ma and two secondary date peaks at 405 Ma and 262 Ma; (4) the mean age of youngest two zircon grains of M152-S1 was 254.8 ± 4.7 Ma, while that of M152-S2 was 257.6 ± 3.8 Ma, suggesting the Baikouquan Formation might be deposited after the Changhsingian to Olenekian; (5) the magmatic rock ages of central West Junggar were distributed mostly between 450–260 Ma, with a dominant age peak at 307 Ma. The ages distribution between magmatic rock of central WJ and detrital zircons of M152-S1 and M152-S2 were similar, indicating the central WJ domain should be the major source area of the Xiazijie fan-delta; (6) the magmatic rock of Hakedun–Hongguleleng area in the Central WJ was characterized by a peak age at 305Ma, which was consistent with the peak ages of M152-S1 and M152-S2, indicating the Hakedun-Hongguleleng area was likely to be their major source area; and (7) one minor peak age at 411 Ma and another at 405 Ma were obtained from M152-S1 and M152-S2, respectively, and a zircon grain with Middle Ordovician age at 467 Ma was obtained from M152-S2, indicating Late Silurian–Early Devonian Chagankule pluton in the Saier Mountain and Ordovician Honggleleng ophiolite mélange in the Sharburt mountain were the minor source areas. This research has significant implications for stratigraphic correlation in Junggar basin and hydrocarbon exploration in the Xiazijie fan-delta conglomerate reservoir.
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Constable, P. D., K. W. Hinchcliff, J. Olson e R. L. Hamlin. "Athletic heart syndrome in dogs competing in a long-distance sled race". Journal of Applied Physiology 76, n.º 1 (1 de janeiro de 1994): 433–38. http://dx.doi.org/10.1152/jappl.1994.76.1.433.
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The cardiac effects of endurance training were evaluated by cardiac auscultation and electrocardiographic examination of 48 heavily trained sled dogs (3,000–5,000 km of training), 18 lightly trained sled dogs (300–800 km of training), 19 untrained sled dogs, and 14 mongrel dogs. A grade I-II/VI early- to midsystolic cardiac murmur was auscultated with increasing frequency as training level increased. The QRS duration (66.1 +/- 7.4 ms) and QT interval (236 +/- 20 ms) were significantly (P < 0.05) longer in heavily trained sled dogs than in mongrel dogs (QRS, 60.6 +/- 4.6; QT, 219 +/- 11 ms). A long QT interval (> 250 ms) was observed in 8 (16.7%) heavily trained dogs but not in the other groups. A significant rightward shift in the mean electrical axis of ventricular depolarization in the frontal plane was observed in heavily trained sled dogs. The auscultatory and electrocardiographic findings in heavily trained sled dogs were remarkably similar to those reported in elite human endurance athletes, suggesting that endurance-trained sled dogs provide a naturally occurring model for the athletic heart syndrome.
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Shtrygol’, Sergiy, Olga Koiro, Olesia Kudina, Olga Tovchiga, Tetiana Yudkevych e Denys Oklei. "The influence of non-steroidal anti-inflammatory drugs with different mechanisms of action on the course of stress reaction, the functional state of kidneys, liver, and heart on the model of acute general cooling". ScienceRise: Pharmaceutical Science, n.º 2(36) (29 de abril de 2022): 46–55. http://dx.doi.org/10.15587/2519-4852.2022.255797.
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Inhibitors of the arachidonic acid cascade have significant potential as the agents for the prevention of severe cold injuries. The results of the previous studies have demonstrated the pronounced frigoprotective properties of certain non-steroidal anti-inflammatory drugs, primarily diclofenac sodium, etoricoxib, darbufelone mesylate, under the conditions of acute general cooling.
The aim of the study: to investigate the effect of non-steroidal anti-inflammatory drugs with various mechanisms of action on the course of the stress reaction, the functional state of the kidneys, liver, and heart using the model of acute general cooling.
Materials and Methods: The experiment was carried out using 35 outbreed male rats weighing 256±5 g. The studied drugs were administered intragastrically 30 minutes before cold injury modelling: diclofenac sodium at a dose of 7 mg/kg, etoricoxib at a dose of 5 mg/kg, darbufelone mesylate at a dose of 20 mg/kg. Acute general cooling was induced by exposure at –18 °C for 2 hours. The efficacy of the studied drugs was evaluated by the values as follows: the body temperature (measured rectally), the course of a stress reaction according to the criteria of “the stress triad”, the functional state of the kidney and liver according to the changes in the blood serum biochemical parameters, the functional state of the heart according to the electrocardiogram.
Results: It was found that etoricoxib and darbufelone mesylate, and especially diclofenac sodium, demonstrate frigoprotective properties, reducing the severity of hypothermia, have stress-protective activity and a beneficial effect on the functional state of the kidneys. All investigated non-steroidal anti-inflammatory drugs prevent a decrease in myocardial contractility (by the effect on the systolic index) and lengthening of the QT interval caused by acute cold injury. Diclofenac sodium, unlike etoricoxib and darbufelone mesylate, does not enhance the effect of acute general cooling on intraventricular conduction. Under acute exposure to cold, no significant changes in the functional state of the liver were observed, including the groups receiving the nonsteroidal anti-inflammatory medicines.
Conclusions: The prophylactic administration of the arachidonic acid cascade inhibitors, especially the non-selective COX-2 inhibitor diclofenac sodium, reduces the severity of the stress response, contributes to the maintenance of the renal and cardiac function. There are no significant changes in the functional state of the liver under conditions of the experiment
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Breen, P. H., P. T. Schumacker, J. Sandoval, I. Mayers, L. Oppenheimer e L. D. Wood. "Increased cardiac output increases shunt: role of pulmonary edema and perfusion". Journal of Applied Physiology 59, n.º 4 (1 de outubro de 1985): 1313–21. http://dx.doi.org/10.1152/jappl.1985.59.4.1313.
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In low-pressure pulmonary edema increased cardiac output (QT) increases shunt (Qs/QT); we tested whether the mechanism is an increase in extravascular lung water in turn mediated by the accompanying increase in microvascular pressure. In six pentobarbital sodium-anesthetized dogs ventilated with O2 we administered oleic acid into the right atrium. From base line to 2 h post-oleic acid we measured concurrent significant increases in Qs/QT (6–29%, O2 technique) and extravascular thermal volume (ETV, 2.6–7.1 ml/g dry intravascular blood-free lung wt, thermal-green dye indicator technique) that were stable by 90 min. Then, bilateral femoral arteriovenous fistulas were opened and closed in 30-min periods to cause reversible increases in QT and associated Qs/QT. When fistulas were open the time-averaged QT increased from 5.1 to 6.9 min (P less than 0.05), the simultaneous Qs/QT rose from 30.7 to 38.4% (P less than 0.05), but ETV did not increase. We conclude that increasing lung edema does not account for our rise in Qs/QT when QT increased.
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Christensen, Louise, J. Rick Turner, Gregory M. Peterson, Mark Naunton, Jackson Thomas, Kwang Choon Yee e Sam Kosari. "Identification of Risk of QT Prolongation by Pharmacists When Conducting Medication Reviews in Residential Aged Care Settings: A Missed Opportunity?" Journal of Clinical Medicine 8, n.º 11 (4 de novembro de 2019): 1866. http://dx.doi.org/10.3390/jcm8111866.
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QT interval prolongation is associated with torsade de pointes and sudden cardiac death. QT prolongation can be caused by many drugs that are commonly prescribed in elderly residential aged care populations. The aim of this study was to investigate the prevalence of use of QT-prolonging drugs and to identify interventions made by pharmacists to reduce the risk of QT prolongation when conducting medication reviews in aged care. A retrospective analysis of 400 medication reviews undertaken by Australian pharmacists in aged care settings was conducted. The assessment included the risk of QT prolongation due to prescribed medications and other risk factors and the recommendations made by pharmacists to reduce the risk of QT prolongation. There was a high prevalence of the use of QT-prolonging medication, with 23% of residents (92 out of 400) taking at least one medication with a known risk of QT prolongation. Amongst the 945 prescribed drugs with any risk of QT prolongation, antipsychotics were the most common (n = 246, 26%), followed by antidepressants (19%) and proton pump inhibitors (13%). There appeared to be low awareness amongst the pharmacists regarding the risk of QT prolongation with drugs. Out of 400 reviews, 66 residents were categorised as high risk and were taking at least one medication associated with QT prolongation; yet pharmacists intervened in only six instances (9%), mostly when two QT-prolonging medications were prescribed. There is a need to increase awareness amongst pharmacists conducting medication reviews regarding the risk factors associated with QT prolongation, and further education is generally needed in this area.
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Samura, Lisa, Cahaya Rosyidan, Mustamina Maulani, Suryo Prakoso, Bayu Satiyawira, Maman Djumantara, Onnie Ridaliani, Mulia Ginting e Mohammad Apriniyadi. "Physical property comparison of polymeric KCl sludge composition and polyamine at different temperatures". IOP Conference Series: Earth and Environmental Science 1339, n.º 1 (1 de maio de 2024): 012020. http://dx.doi.org/10.1088/1755-1315/1339/1/012020.
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Abstract Drilling mud is a fluid used to assist the drilling process. The composition and physical properties of the mud greatly influence a drilling operation. Drilling operations that penetrate formations with shale content have the potential to experience drilling problems related to shale hydration. To get a good ability to prevent shale hydration, mud is added with polymeric and polyamine KCl additives (shale inhibitors) with the aim of stabilizing shale in contact with drilling fluid, as well as preventing drill cuttings from forming colloids. The results obtained in the KCl polymer mud composition at temperatures of 80°F, 250°F, and 300°F for mud weight were 9.3 ppg, 9.1 ppg, and 9 ppg, respectively. Funnel viscosity was 40 sec/qt, 36 sec/qt, and 34 sec/qt. Tap rates were 4.8 cc, 6 cc, and 6.6 cc. Mud cake remained at 1 mm and pH also remained at 9. While the results obtained on polyamine mud composition at temperatures of 80°F, 250°F, and 300°F for mud weight were 9.2 ppg, 8.9 ppg, and 8.8 ppg, respectively. Funnel viscosity was 26 sec/qt, 20 sec/qt, and 17 sec/qt. Tap rate of 10 cc, 13.8 cc, and 15 cc. Mud cake of 1 mm, 2 mm, and 2 mm. pH remains at 9. The data obtained shows that the results of the physical properties of polymeric KCl mud are better than polyamine mud.
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Sugiyama, Atsushi, Hiroya Hashimoto, Yuji Nakamura, Tomoe Fujita e Yuji Kumagai. "QT/QTc study conducted in Japanese adult healthy subjects: A novel xanthine oxidase inhibitor topiroxostat was not associated with QT prolongation". Journal of Clinical Pharmacology 54, n.º 4 (22 de novembro de 2013): 446–52. http://dx.doi.org/10.1002/jcph.226.
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Karahan, Zulkuf, Murat Ugurlu, Berzal Ucaman, Ali Veysel Ulug, Ilyas Kaya, Kemal Cevik, Mehmet Sahin Adiyaman, Onder Oztürk, Hikmet Iyem e Ferit Ozdemir. "Association Between ACE Gene Polymorphism and QT Dispersion in Patients with Acute Myocardial Infarction". Open Cardiovascular Medicine Journal 10, n.º 1 (31 de maio de 2016): 117–21. http://dx.doi.org/10.2174/1874192401610010117.
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Background: Angiotensin converting enzyme (ACE) gene polymorphism is associated with high renin-angiotensin system causing myocardial fibrosis and ventricular repolarization abnormality. Based on these findings, this study was designed to determine the association between ACE gene insertion/deletion (I/D) polymorphism and QT dispersion after acute myocardial infarction (MI). Objective and Methods: The study included 108 patients with acute MI. Blood samples were obtained from all the patients for genomic DNA analysis. ECGs were recorded at baseline and at the end of a 6-month follow up. The OT dispersion was manually calculated. Results: The mean age of the patients was 57.5 ±9.9 years (ranging from 36 to 70). The patients with DD genotype showed longer QT dispersion than patients with II or DI genotype at the baseline, while at the end of the six-month follow up the patients with DI genotype showed longer QT dispersion than patients with DD or II genotypes. However, the magnitude of the QT dispersion prolongation was higher in patients carrying the ACE D allele than patients who were not carrying it, at baseline and at the end of six-month follow up (52.5 ±2.6 msn vs. 47.5±2.1 msn at baseline, 57±3.2 msn vs. 53±2.6 msn in months, P: 0.428 and P: 0.613, respectively). Conclusion: Carriers of the D allele of ACE gene I/D polymorphism may be associated with QT dispersion prolongation in patients with MI.An interaction of QT dispersion and ACE gene polymorphism may be associated with an elevation of serum type I-C terminal pro-collagen concentration, possibly leading to myocardial fibrosis, and increased action potential duration.
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Radermacher, P., R. Herigault, B. Teisseire, A. Harf e F. Lemaire. "Low VA/Q areas: arterial-alveolar N2 difference and multiple inert gas elimination technique". Journal of Applied Physiology 64, n.º 5 (1 de maio de 1988): 2224–29. http://dx.doi.org/10.1152/jappl.1988.64.5.2224.
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In 16 critically ill patients the arterial-alveolar N2 difference and data from the multiple inert gas elimination technique (MIGET) were compared in the evaluation of the contribution of low alveolar ventilation-perfusion ratio (VA/Q) lung regions (0.005 less than VA/Q less than 0.1) to venous admixture (Qva/QT). The arterial-alveolar N2 difference was determined using a manometric technique for the measurement of the arterial N2 partial pressure (PN2). We adopted a two-compartment model of the lung, one compartment having a VA/Q of approximately 1, the other being open, gas filled, unventilated (VA/Q = 0), and in equilibrium with the mixed venous blood. This theoretical single compartment represents all lung regions responsible for the arterial-alveolar N2 difference. The fractional blood flow to this compartment was calculated using an appropriate mixing equation (Q0/QT). There was a weak but significant relationship between Q0/QT and the perfusion fraction to lung regions with low VA/Q (0.005 less than VA/Q less than 0.1) (r = 0.542, P less than 0.05) and a close relationship between Q0/QT and the perfusion fraction to lung regions with VA/Q ratios less than 0.9 (r = 0.862, P less than 0.001) as obtained from MIGET. The difference Qva/QT-Q0/QT yielded a close estimation of the MIGET right-to-left shunt (Qs/QT) (r = 0.962, P less than 0.001). We conclude that the assessment of the arterial-alveolar N2 difference and Q0/QT does not yield a quantitative estimation of the contribution of pathologically low VA/Q areas to QVa/QT because these parameters reflect an unknown combination of pathological and normal (0.1 less than VA/Q less than 0.9) gas exchange units.(ABSTRACT TRUNCATED AT 250 WORDS)
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Norris, Aaron B., Whitney L. Crossland, Luis O. Tedeschi, Jamie L. Foster, James P. Muir e William Pinchak. "PSIX-38 Influence of quebracho (Schinopsis balansae) tannin extract fed at differing rates in a high-roughage diet on energy partitioning in beef steers". Journal of Animal Science 97, Supplement_3 (dezembro de 2019): 391–92. http://dx.doi.org/10.1093/jas/skz258.780.
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Abstract Our objective was to evaluate how quebracho tannin (QT; Schinopsis balansae) within a roughage-based diet affected energy partitioning of growing beef steers. Ruminant production is essential to meeting the protein requirements of an increasing global population. However, gaseous byproducts from ruminant production, such as methane (CH4), not only reduce energetic efficiency, it can also be detrimental to the environment. Feed-grade antibiotics have traditionally been utilized for improved feed efficiency; however, consumer perception has prompted the pursuit of natural rumen modulators. Condensed tannins are a potential alternative due to their capacity for enhancing protein efficiency and reducing CH4. In our study, a 4 x 8 Latin rectangle design utilizing four periods and 8 British crossbred steers (236 ± 16 kg) were used to determine the effects of QT fed at 0 (control), 1.5, 3, and 4.5% of DM, within a roughage-based ration. Following 12-d dietary adaptation, animals were relocated to open-circuit respiration calorimetry chambers fitted with metabolism stands for gas exchange measurements and collection of total feces and urine over 48 h. Data were analyzed using a random coefficients model with animal and period as random factors. Inclusion of QT had no effect on intake, fiber digestibility, or nitrogen retention (P > 0.10). Provision of QT increased fecal energy, resulting in reduced digestible energy (DE) (P < 0.01). Urinary energy was not different (P = 0.49) but gas energy decreased (P < 0.01) as QT inclusion increased. Metabolizable energy (ME) decreased linearly as QT increased (P < 0.01), but all treatments maintained a ME-to-DE ratio of 0.86. Heat energy decreased (P = 0.01) with increased QT rate; however, there was no difference in retained energy. Although QT reduced gas and heat energy, this could not compensate for the reduction in digestible energy, leading to decreased energetic efficiency with QT inclusion.
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Pezo, Rossanna C., Andrew T. Yan, Craig Earle e Kelvin K. Chan. "Underuse of ECG monitoring in oncology patients receiving QT-interval prolonging drugs". Heart 105, n.º 21 (25 de maio de 2019): 1649–55. http://dx.doi.org/10.1136/heartjnl-2018-314674.
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ObjectiveWe examined use of ECG monitoring in oncology patients prescribed QT-prolonging drugs.MethodsPatients ≥66 years diagnosed with cancer between 2005 and 2011 were identified through the Ontario Cancer Registry and linked to multiple population-based administrative databases to ascertain demographics, comorbidities, prescription drug use, systemic therapy and ECG. QT-prolonging drugs were identified as per drug lists developed by the Arizona Center for Education and Research on Therapeutics. Univariable and multivariable analyses were used to examine factors associated with ECG use in patients on first-line systemic therapy.ResultsA total of 48 236 patients (median age 74; 49% women) received one or more drugs associated with a risk of QT-interval prolongation but only 27% of patients had an ECG performed. Factors associated with more ECG use on multivariable analysis included recent cancer diagnosis (p for trend <0.001 between 2005 and 2011), use of concurrent QT-prolonging drugs (OR=1.15 per each additional QT-prolonging drug, 95% CI 1.12 to 1.17) and the presence of coronary artery disease (OR 1.31; 95% CI 1.25 to 1.38) and heart failure (OR 1.25; 95% CI 1.17 to 1.35). Use of anticancer (OR 0.74; 95% CI 0.70 to 0.79) and antiemetic (OR 0.93; 95% CI 0.88 to 0.99) QT-prolonging drugs was paradoxically associated with less ECG use.ConclusionsOur study highlights common use of QT-prolonging drugs and underuse of ECG in oncology patients. Since ECG is an inexpensive, non-invasive and widely available test, it may be readily incorporated in the monitoring of patients for toxicities in routine clinical practice.
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Abarikwu, Sunny O., e Ebenezer O. Farombi. "Quercetin ameliorates atrazine-induced changes in the testicular function of rats". Toxicology and Industrial Health 32, n.º 7 (26 de novembro de 2014): 1278–85. http://dx.doi.org/10.1177/0748233714555389.
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The protective effect of quercetin (QT) on atrazine (ATZ)-induced testicular damage in rats was investigated. Sexually mature male Wistar rats (weighing 220–250 g) divided into four groups with six animals in each group were given ATZ (120 mg kg−1; 1/16 of the median lethal dose for an oral dose) and/or QT (10 mg kg−1) daily via gavage for 16 days. By the end of day 16, rats given ATZ alone had significantly lower sperm counts, daily spermatozoa production, and sperm motility and significantly higher abnormal sperm numbers than the untreated control rats. The rats given ATZ alone also had significantly decreased 3β-hydroxtsteroid dehydrogenase (HSD) and 17β-HSD activities than the control rats. Lactate dehydrogenase activity and malondialdehyde levels were significantly increased, whereas superoxide dismutase activity decreased but glutathione levels remain unaffected after ATZ exposure. These changes were reversed toward control values in the QT + ATZ-treated animals, though the sperm motility was 28% below the control levels but was still higher than in the ATZ-treated rats. The results indicate that QT might improve testicular function of rats exposed to ATZ, but its protective effect on sperm motility might be partial.
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O'Mara, Edward, Claudia Kasserra, John Robert Huddlestone, Yuntao Wan, Peter Soni, Maria Caceres, Matthew Medlock, Royce Morrison e Orrin Devinsky. "Effect of Vicriviroc on the QT/Corrected QT Interval and Central Nervous System in Healthy Subjects". Antimicrobial Agents and Chemotherapy 54, n.º 6 (29 de março de 2010): 2448–54. http://dx.doi.org/10.1128/aac.01447-09.
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ABSTRACT Vicriviroc is a CCR5 antagonist in clinical development for the treatment of HIV-1. Two phase I studies were conducted to assess the safety of vicriviroc. One study characterized the drug's potential to prolong the QT/corrected QT (QTc) interval and to induce arrhythmia. In this partially blind, parallel-group study, 200 healthy subjects aged 18 to 50 years were randomized in equal groups to the following regimens: (i) placebo for 9 days and a single dose of moxifloxacin at 400 mg on day 10, (ii) placebo, (iii) vicriviroc-ritonavir (30 and 100 mg), (iv) vicriviroc-ritonavir (150 and 100 mg), and (v) ritonavir (100 mg). The second study characterized the effects of a range of vicriviroc doses on the central nervous system (CNS). In this third-party-blind, parallel-group study, 30 healthy subjects aged 18 to 48 years were randomized to receive a single dose of either vicriviroc at 200, 250, or 300 mg or placebo, followed by multiple (seven) once-daily doses of either vicriviroc at 150, 200, or 250 mg or placebo, respectively. In the first study, vicriviroc produced no clinically meaningful effect on the QT/QTc interval when administered at a supratherapeutic or therapeutic dose concurrently with ritonavir. In the second study, vicriviroc produced no observable seizure activity, nor was it held to be associated with any clinically relevant changes in brain waveforms in the final consensus of reviewers. These findings showed that vicriviroc produced no clinically relevant QTc prolongation cardiac or epileptogenic effects in healthy individuals at exposures as high as five times those expected for HIV-infected patients receiving therapeutic doses of vicriviroc in a ritonavir-boosted protease inhibitor-containing regimen.
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Sonawane, D., e V. Pokharkar. "Donepezil and Quercetin Simultaneous Estimation in Rat Plasma Using Developed Bioanalytical HPLC Method: Relevance in Pharmacokinetic Studies". INTERNATIONAL JOURNAL OF DRUG DELIVERY TECHNOLOGY 13, n.º 04 (25 de dezembro de 2023): 1538–43. http://dx.doi.org/10.25258/ijddt.13.4.64.
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The objective of this investigation was to create and apply a reliable reverse phase high performance liquid chromatography (RP-HPLC) technique for the concurrent measurement of donepezil (DPZ) and quercetin (QT) in rat blood samples for pharmacokinetic research. This is the first publication that introduces a method for DPZ and QT simultaneous determination in rat plasma by high-performance liquid chromatography (HPLC). Using a mobile phase of methanol and HPLC grade water (pH 2.8; adjusted with 0.05% v/v orthophosphoric acid) 45:55 v/v with 2-3 drops of triethylamine (TEA) in an isocratic elution mode at flow rate of 1.0ml/min, DPZ and QT were successfully separated chromatographically on a Hypersil gold C-18 column (250 mm × 4.6 mm, 5μm). The retention time for DPZ and QT was observed to be 6.3 and 12.3 minutes and was detected at an isobestic wavelength of 273 nm using a UV detector. The method was shown to be precise (%RSD < 2%), accurate (96–100%), and specific for the simultaneous detection of DPZ and QT. Several freeze-thaw cycles of the treated plasma samples did not significantly affect the analyte’s stability. The method’s applicability was subsequently confirmed through an oral pharmacokinetic investigation in rats. Since the results were deemed trustworthy, the validated RP-HPLC method may be used to simultaneously detect and quantify both drugs. The method worked well for evaluating the pharmacokinetic characteristics in wistar rats following a single oral dose of 5 mg/kg of QT and 10 mg/kg of DPZ. It is well acknowledged that the chromatographic process is straightforward, robust, accurate, exact, and repeatable.
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Oczenski, Wolfgang, Christoph Hörmann, Christian Keller, Norbert Lorenzl, Anton Kepka, Sylvia Schwarz e Robert D. Fitzgerald. "Recruitment Maneuvers after a Positive End-expiratory Pressure Trial Do Not Induce Sustained Effects in Early Adult Respiratory Distress Syndrome". Anesthesiology 101, n.º 3 (1 de setembro de 2004): 620–25. http://dx.doi.org/10.1097/00000542-200409000-00010.
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Background Recruitment maneuvers performed in early adult respiratory distress syndrome remain a matter of dispute in patients ventilated with low tidal volumes and high levels of positive end-expiratory pressure (PEEP). In this prospective, randomized controlled study the authors evaluated the impact of recruitment maneuvers after a PEEP trial on oxygenation and venous admixture (Qs/Qt) in patients with early extrapulmonary adult respiratory distress syndrome. Methods After a PEEP trial 30 consecutive patients ventilated with low tidal volumes and high levels of PEEP were randomly assigned to either undergo a recruitment maneuver or not. Data were recorded at baseline, 3 min after the recruitment maneuver, and 30 min after baseline. Recruitment maneuvers were performed with a sustained inflation of 50 cm H2O maintained for 30 s. Results Compared with baseline the ratio of the arterial oxygen partial pressure to the fraction of inspired oxygen (Pao2/Fio2) and Qs/Qt improved significantly at 3 min after the recruitment maneuver (Pao2/Fio2, 139 +/- 46 mm Hg versus 246 +/- 111 mm Hg, P < 0.001; Qs/Qt, 30.8 +/- 5.8% versus 21.5 +/- 9.7%, P < 0.005), but baseline values were reached again within 30 min. No significant differences in Pao2/Fio2 and Qs/Qt were detected between the recruitment maneuver group and the control group at baseline and after 30 min (recruitment maneuver group [n = 15]: Pao2/Fio2, 139 +/- 46 mm Hg versus 138 +/- 39 mm Hg; Qs/Qt, 30.8 +/- 5.8% versus 29.2 +/- 7.4%; control group: [n = 15]: Pao2/Fio2, 145 +/- 33 mm Hg versus 155 +/- 52 mm Hg; Qs/Qt, 30.2 +/- 8.5% versus 28.1 +/- 5.4%). Conclusion In patients with early extrapulmonary adult respiratory distress syndrome who underwent a PEEP trial, recruitment maneuvers failed to induce a sustained improvement of oxygenation and venous admixture.
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Runer, Armin, Robert Csapo, Caroline Hepperger, Mirco Herbort, Christian Hoser e Christian Fink. "Anterior Cruciate Ligament Reconstructions With Quadriceps Tendon Autograft Result in Lower Graft Rupture Rates but Similar Patient-Reported Outcomes as Compared With Hamstring Tendon Autograft: A Comparison of 875 Patients". American Journal of Sports Medicine 48, n.º 9 (julho de 2020): 2195–204. http://dx.doi.org/10.1177/0363546520931829.
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Background: Graft rupture is a devastating outcome after anterior cruciate ligament (ACL) reconstruction (ACLR). Little is known about graft rupture rates as well as clinical and functional outcomes after ACLR with quadriceps tendon (QT) autografts. Purpose: To compare QT with hamstring tendon (HT) autografts in terms of the rates of graft and contralateral ACL rupture as well as patient-reported outcome measures. Study Design: Cohort study; Level of evidence, 3. Methods: All primary ACLRs performed between 2010 and 2016 were followed prospectively for 24 months through the recording of graft ruptures and contralateral ACL injuries as well as patient-administered questionnaires. Results: A total of 875 patients were included in the study. Three factors—graft type, age group, and activity level—had a significant value in predicting the need for revision surgery. The odds of revision surgery were 5.5 times greater in children younger than 15 years than in adults older than 45 years, 3.6 times greater in patients with high activity levels than low activity levels, and 2.7 times greater in patients receiving an HT autograft as compared with a QT autograft. A significantly higher rate of ipsilateral graft ruptures versus contralateral ACL injuries was observed in the HT group (4.9% vs 2.3%; odds ratio, 2.1; P = .01) but not in the QT group (2.8% vs 2.3%). The difference in the ratios of graft and contralateral ACL ruptures was even more pronounced in highly active patients treated with HT autografts (11.1% vs 4.2%; odds ratio, 2.6; P = .01) as compared with QT autografts (5.0% vs 2.8%; P = .48). Two-year measures of Lysholm scores (mean ± SD: QT, 86.0 ± 22.3; HT, 89.4 ± 16.4) and Tegner activity scores (QT, 6.1 ± 2.0; HT, 5.7 ± 1.9) as well as visual analog scale pain (QT, 0.8 ± 1.3; HT, 0.7 ± 1.1) did not differ between grafts. Conclusion: Graft choice does not influence clinical and functional outcomes 2 years after ACLR. However, 3 factors—graft type, age group, and activity level—have a significant value in predicting the need for revision surgery. Patients treated with HT autografts have a significantly higher, activity-dependent risk of revision surgery and experience more ipsilateral graft ruptures than subsequent contralateral ACL injuries when compared with patients treated with QT autografts. Young age and high activity level are significant predictors for ACL revision surgery.
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CHAUFFERT, Bruno. "Weekly Carboplatin, Paclitaxel and Cetuximab with Pembrolizumab Every 3 Weeks Is Active and Tolerated in Patients with Locally Advanced and/or Metastatic/Recurrent Head and Neck Squamous Cell Carcinoma". Cancer Research and Cellular Therapeutics 8, n.º 1 (26 de fevereiro de 2023): 01–04. http://dx.doi.org/10.31579/2640-1053/185.
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The management of recurrent/metastatic head and neck carcinoma (R/M HNSCC) is evolving with new available molecules and combination modalities. Anti-EGFR cetuximab and immune checkpoint inhibitors (ICI) are used either alone or in combination with conventional platinum-based doublet chemotherapy (with taxanes or fluorouracil). Few data have been reported on the combination of doublet chemotherapy with both cetuximab and ICI. Here, we review a series of 17 patients that received a quadritherapy (QT) with paclitaxel, 60 mg/m2/week, carboplatin, AUC 1.5/week, cetuximab, 250 mg/m2 /week, and pembrolizumab, 200 mg every 3 weeks. Nine to 12 weekly injections were done before evaluation by clinical examination and PET-CT. Nine patients with bulky advanced disease responded to QT (3 complete responses (CR), 6 partial responses (PR)). Seven patients further received a cisplatin-based chemoradiotherapy (CRT). Eight out of nine patients are still in CR. Eight patients received QT for recurrent and/or metastatic disease. One CR, 3 PR and 3 stable diseases were recorded. Adverse events were minor, except for an ICI-related grade 3 cardiac toxicity. Overall, this short series indicates that QT with weekly carboplatin-paclitaxel-cetuximab and pembrolizumab every 3 weeks is safe and active in patients with advanced or R/M HNSCC. These results should be confirmed through further randomized trials.
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Scardella, A. T., J. A. Neubauer, N. H. Edelman e T. V. Santiago. "Modulation by endogenous opioids of pulmonary vasoconstrictor response to acute lung injury". Journal of Applied Physiology 64, n.º 5 (1 de maio de 1988): 1823–28. http://dx.doi.org/10.1152/jappl.1988.64.5.1823.
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The effects of endogenously generated opioids on distribution of pulmonary perfusion (as assessed by radiolabeled microspheres) and overall gas exchange in acute acid-induced lung injury were studied. In 14 anesthesized dogs, sufficient acid was given to one lung to double shunt fraction (Qs/Qt) from 14.2 +/- 0.8 to 32.4 +/- 2.6% (SE). This resulted in a significant decrease in Po2 from 495 +/- 9 to 136 +/- 21 Torr, cardiac output from 2.47 +/- 0.27 to 1.46 +/- 0.15 1/min, and blood pressure from 139 +/- 3 to 116 +/- 5 mmHg and a significant rise in pulmonary arterial pressure from 9.6 +/- 0.8 to 14.9 +/- 0.8 mmHg. After acid instillation, microsphere distribution to the injured lung segments decreased to 50% of the base-line value. At the same time, microsphere distribution in the normal segments increased to 160% of base line. In 7 of the 14 dogs the effects of naloxone (1 mg/kg) given after lung injury were compared with the other 7 animals that were given saline. Naloxone administration caused a significant redistribution of regional pulmonary perfusion such that microsphere distribution in the injured lung segments increased by a factor of 2 at 35 min compared with the animals given saline. Consistent with this finding, Qs/Qt in the naloxone group increased to 34.7 +/- 5.0% at 35 min, whereas that of the saline group decreased to 28.2 +/- 2.5%. The difference between the two groups was significant at 35 min. These changes occurred without further alterations in cardiac output, pulmonary arterial pressure, or systemic blood pressure in either group.(ABSTRACT TRUNCATED AT 250 WORDS)
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Schmücker, Malte, Jørgen Haraszuk, Per Hölmich e Kristoffer W. Barfod. "Graft Failure, Revision ACLR, and Reoperation Rates After ACLR With Quadriceps Tendon Versus Hamstring Tendon Autografts: A Registry Study With Review of 475 Patients". American Journal of Sports Medicine 49, n.º 8 (8 de junho de 2021): 2136–43. http://dx.doi.org/10.1177/03635465211015172.
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Background: It has been indicated that anterior cruciate ligament reconstruction (ACLR) with a quadriceps tendon (QT) graft has a higher risk of revision compared with ACLR performed with a hamstring tendon (HT) graft. Purpose/Hypothesis: To investigate whether ACLR with QT graft had a higher risk of graft failure, revision ACLR, or reoperation compared with HT graft in a high-volume center. We hypothesized that there would be no between-group differences. Study Design: Cohort study; Level of evidence, 3. Methods: This was a registry study with review of medical records. Our study cohort consisted of patients who underwent primary ACLR with either QT or HT graft performed at Copenhagen University Hospital Hvidovre between January 2015 and December 2018. The cohort was identified from the Danish Knee Ligament Reconstruction Registry and linked to the Danish National Patient Registry to identify all hospital contacts after ACLR. The outcome variables were graft failure (rerupture or >3-mm side-to-side difference in anteroposterior [AP] laxity), revision ACLR, reoperation due to cyclops lesion, reoperation due to meniscal injury, and reoperation due to any reason. AP laxity and pivot shift were assessed at 1 year. Kaplan-Meier estimates were used to evaluate the rates of events at 2 years, and comparison was performed with Cox regression analysis. Results: A total of 475 patients (252 HT, 223 QT) were included. The rate of graft failure at 2 years was 9.4% for the QT group and 11.1% for the HT group ( P = .46). For the QT and HT groups, respectively, the rate of revision ACLR was 2.3% and 1.6% ( P = .60), the rate of reoperation due to cyclops lesion was 5.0% and 2.4% ( P = .13), and the rate of reoperation due to meniscal injury was 4.3% and 7.1% ( P = .16). The rate of reoperation due to any reason was 20.5% and 23.6% ( P = .37). At 1-year follow-up, AP laxity was 1.4 mm for QT and 1.5 mm for HT ( P = .51), and the proportion of patients with a positive pivot shift was 29-30% for both groups. Conclusion: QT and HT grafts yielded similar rates of graft failure, revision ACLR, and reoperation at 2 years of follow-up after ACLR. Graft failure was found in 9% to 11% of patients. Patients with QT ACLR showed a non–statistically significant trend of higher risk for reoperation due to cyclops lesion, and those with HT showed a non–statistically significant trend of higher risk for reoperation due to meniscal injury.
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Carlile, P. V., S. F. Hagan e B. A. Gray. "Perfusion distribution and lung thermal volume in canine hydrochloric acid aspiration". Journal of Applied Physiology 65, n.º 2 (1 de agosto de 1988): 750–59. http://dx.doi.org/10.1152/jappl.1988.65.2.750.
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We investigated the effects of a brief period of positive end-expiratory pressure (PEEP) ventilation or nitroglycerin (NTG) infusion on the distribution of pulmonary blood flow and extravascular thermal volume (ETV) in anesthetized dogs with unilateral HCl lung injury. ETV was determined by the thermal dye technique by use of a monoexponential extrapolation to exclude recirculating indicator, and regional blood flow was determined by a particle distribution technique (radiolabeled plastic microspheres). The lungs were weighted after the animals were killed, and extravascular lung mass (ELM) was determined with the use of hemoglobin to correct for trapped lung blood. Measurements were obtained before instillation of HCl into the right lung and repeated 3 h later before, during, and after PEEP ventilation or NTG infusion. Fractional perfusion of the severely injured portion of the right lung (Qinj/QT) fell from 44.3 +/- 11.1% at base line to 27.8 +/- 15.4% after the onset of lung injury. PEEP produced an acute reversible increase in ETV (63 +/- 37% over average of pre- and post-PEEP values), and the changes in ETV were closely correlated with changes in Qinj/QT (r = 0.91). NTG infusion produced insignificant increases in ETV (14 +/- 10% over average of pre- and postinfusion values) and Qinj/QT (59 +/- 35%), but the changes in ETV and Qinj/QT were strongly correlated (r = 0.92). The fraction of extravascular lung mass detected by the thermodilution measurement averaged 0.44 (range 0.24-0.77).(ABSTRACT TRUNCATED AT 250 WORDS)
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Yao, Ying Biao, Xian Bin Zeng e Guang Pei Zhao. "Design and Implementation of MIPS Simulator Oriented Memory Hierarchy Research". Applied Mechanics and Materials 236-237 (novembro de 2012): 907–12. http://dx.doi.org/10.4028/www.scientific.net/amm.236-237.907.
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MIPS processor is widely used in embedded system, whose memory hierarchy has such an important effect on the performance and cost that how to design memory hierarchy rapidly is a key problem. To deal with the MIPS memory hierarchy research, we design a MIPS simulator “QtMips”. It is a GUI, Qt-based simulator for MIPS assembly language, which not only collects and analyzes real-time simulation information, but also supports fast memory configuration setting such as hierarchy setting, allocation setting, etc.
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Anand, Kartik, Joe Ensor, Barry Trachtenberg e Eric Bernicker. "Osimertinib induced cardio-toxicity: A retrospective review of FDA adverse events reporting system (FAERS)." Journal of Clinical Oncology 37, n.º 15_suppl (20 de maio de 2019): 9044. http://dx.doi.org/10.1200/jco.2019.37.15_suppl.9044.
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9044 Background: Osimertinib is an oral third generation irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). In the FLAURA trial (a Phase III randomized-control trial) Osimertinib arm had higher rate of cardio-toxicity compared to standard EGFR-TKIs. We queried FAERS database to find out rate of cardio-toxicity caused by Osimertinib compared to other EGFR-TKIs. Methods: We queried FAERS for “Cardiac failure”, “Electrogram QT-prolonged”, “Atrial Fibrillation(A.fib)”, “Myocardial Infarction(MI)”, “Cardiac failure congestive(CFC)” and “Pericardial Effusion(PE)” secondary to “Osimetinib”, “Erlotonib”, “Afatinib” and “Gefitinib” from 2016-2018. Disproportionality signal analysis was done by calculating Reporting Odds Ratio (ROR) with 95% confidence interval (CI). ROR was considered significant when lower limit of 95% CI was > 1. Results: Total AEs from all drugs were 5,138,230. Total AEs from all 4 TKIs were 8450, 2454 due to Osimertinib, 5836 due to other TKIs and 160 due to combination of both Osimertinib plus any of other 3 TKIs. ROR for Cardiac failure, A.fib, QT prolongation, MI, PE and CFC due to Osimertinib was 6.4(4.7-8.7), 4(2.8-5.8), 11.2(7.9-15.8), 1.6(0.9-2.6), 8.2(4.8-14) and 3.9(2.4-6.3) respectively. ROR for Cardiac failure, A.fib, QT prolongation, MI, PE and CFC on comparing Osimertinib vs other TKIs was 2.1(1.3-3.2), 2.1(1.3-3.5), 6.6(3.4-12.8), 1.2(0.6-2.3), 1.6(0.8-3.3) and 2.3(1.2-4.6) respectively. Findings are summarized in Table. Conclusions: Rate of QT prolongation, cardiac failure, CFC and A.fib were found to be higher due to Osimertinib compared to other TKIs. EKG monitoring for QT prolongation and monitoring for signs/symptoms of heart failure should be considered while using Osimertinib. [Table: see text]
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Roba, Belay, e Fistum Miruts. "On-farm demonstration of improved and drought tolerant maize varieties with associated management practices". Agriculture and Food Sciences Research 10, n.º 2 (6 de dezembro de 2023): 32–36. http://dx.doi.org/10.20448/aesr.v10i2.5210.
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Maize is an important cereal crop in the central Rift Valley of Ethiopia. It plays a greater role in ensuring food security. The study was designed to evaluate and promote Melkassa-6Q variety with standard check (Melkassa-2). The study sites were Adama and ATJK districts. The districts were selected based on their maize production potential and accessibility of the site for demonstration. Training and field days were implemented to facilitate the successful implementation of the activity and create awareness among farmers about the varieties. Grain yield was recorded and the varieties were compared to each other based on their yield performance. Farmers ‘feedback was also collected and farmers preference ranking of each demonstrated variety was done depending on the farmers’ set criteria for variety evaluation. The mean yield of Melkassa-2 (standard check) is about 39 qt/ha across locations whereas the mean yield of Melkassa-6Q is 36.4 qt/ha which is 2.6 qt below the standard check. In addition to yield, Melkassa-2 variety was preferred over Melkassa-6Q variety in overall farmers’ evaluation criteria for maize variety evaluation. Therefore, there should be an adequate quality seed supply of Melkassa-2 variety till the best-performing maize variety is released by the research system.
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Vandenberk, Bert, Tomas Robyns, Christophe Garweg, Joris Ector e Rik Willems. "216-73: QT/RR regression correlation coefficient as non-invasive risk stratification tool". EP Europace 18, suppl_1 (junho de 2016): i29. http://dx.doi.org/10.1093/europace/18.suppl_1.i29b.
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Million, Matthieu, Jean-Christophe Lagier, Jérôme Hourdain, Frédéric Franceschi, Jean-Claude Deharo, Philippe Parola e Philippe Brouqui. "Cardiovascular Safety of Hydroxychloroquine–Azithromycin in 424 COVID-19 Patients". Medicina 59, n.º 5 (29 de abril de 2023): 863. http://dx.doi.org/10.3390/medicina59050863.
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Background and Objectives: Hydroxychloroquine (HCQ) combined with azithromycin (AZM) has been widely administered to patients with COVID-19 despite scientific controversies. In particular, the potential of prolong cardiac repolarization when using this combination has been discussed. Materials and Methods: We report a pragmatic and simple safety approach which we implemented among the first patients treated for COVID-19 in our center in early 2020. Treatment contraindications were the presence of severe structural or electrical heart disease, baseline corrected QT interval (QTc) > 500 ms, hypokalemia, or other drugs prolonging QTc that could not be interrupted. Electrocardiogram and QTc was evaluated at admission and re-evaluated after 48 h of the initial prescription. Results: Among the 424 consecutive adult patients (mean age 46.3 ± 16.1 years; 216 women), 21.5% patients were followed in conventional wards and 78.5% in a day-care unit. A total of 11 patients (2.6%) had contraindications to the HCQ-AZ combination. In the remaining 413 treated patients, there were no arrhythmic events in any patient during the 10-day treatment regimen. QTc was slightly but statistically significantly prolonged by 3.75 ± 25.4 ms after 2 days of treatment (p = 0.003). QTc prolongation was particularly observed in female outpatients <65 years old without cardiovascular disease. Ten patients (2.4%) developed QTc prolongation > 60 ms, and none had QTc > 500 ms. Conclusions: This report does not aim to contribute to knowledge of the efficacy of treating COVID-19 with HCQ-AZ. However, it shows that a simple initial assessment of patient medical history, electrocardiogram (ECG), and kalemia identifies contraindicated patients and enables the safe treatment of COVID-19 patients with HCQ-AZ. QT-prolonging anti-infective drugs can be used safely in acute life-threatening infections, provided that a strict protocol and close collaboration between infectious disease specialists and rhythmologists are applied.
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Gurulev, Dmitriy N., Lyubov V. Palatkina, Anna S. Yudina e Vladimir I. Porkhun. "PROPERTIES OF EXCITED MOLECULES IN PHOTOLYSIS OF 2,6-DIPHENYL-1,4-BENZOQUINONE WITH AMINES". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 61, n.º 8 (21 de agosto de 2018): 27. http://dx.doi.org/10.6060/ivkkt201861008.5755.
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To date, it is considered established that quinones with lower energy state, under the action of light tear away a hydrogen atom from a hydrocarbon or an electron donor from inorganic anion-radicals, which have a high reduction potential. However, even for the simplest quinones (1,4-benzoquinone, 1,4-naphthoquinones, 9,10-anthraquinone and their derivatives) there is no consensus in the science literature about the nature of the initial event in photoreaction with compounds which are potential donors of hydrogen atom and electron. The first step in many photochemical reactions is the formation of complexes between donors and acceptors of electrons in the excited state (exiplexes). Photoreactive quinones as elementary acts include the transfer of electron (or) hydrogen atom. The mechanism depends on the presence and strength of donor-acceptor complexes (DAC) of the quinones with the reagents. Studies of triplet exiplexes allow you to set the details of the elementary reaction acts. Only short-lived intermediate product was registered upon photoexcitation of the studied quinone Q in low-polarity solvents. The kinetic of decay of the first order with rate constant of about 2∙106 s-1 in toluene and dibutylphthalate and the introduction of oxygen leads to a decrease in the lifetime of the product in the triplet state. With the introduction of solutions of amines quenching of triplet state (QT) with rate constant close to diffusion was observed. Rate constants of quenching by dissolving in benzene and by dissolving in dibutyl phthalate were determined. It is established that formation of intermediate products is carried out from triplet state (QT). Excited complexes with charge transfer in acetonitrile were not observed. It is concluded that with decrease in electron affinity of the acceptors, when the connection of the molecules in the complex becomes weaker, the lifetime of TE increases significantly.
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Kako, Hiromi, Senthil G. Krishna, Roby Sebastian, Kyle Smith e Joseph D. Tobias. "Effect of dexmedetomidine on the QT interval in pediatric patients undergoing general anesthesia". Journal of Anesthesia 29, n.º 6 (4 de agosto de 2015): 862–67. http://dx.doi.org/10.1007/s00540-015-2056-2.
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Norris, Aaron B., Luis O. Tedeschi, Jamie L. Foster, James P. Muir e Bill E. Pinchak. "257 Effects of feeding different levels of quebracho (Schinopsis balansae) extract in a high-roughage total mixed ration on seasonal manure gas emissions". Journal of Animal Science 97, Supplement_3 (dezembro de 2019): 93–94. http://dx.doi.org/10.1093/jas/skz258.193.
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Abstract Our objective was to investigate how quebracho tannin (QT; Schinopsis balansae) fed at differing rates within a roughage-based diet affected manure gas emissions of growing steers. The utilization of ruminant species is required for efficient production of human-edible protein to meet global nutrient demands. However, gaseous byproducts from ruminant production systems, such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are deleterious to the environment. It is estimated that CO2, CH4, and N2O from managed waste and grazed lands account for roughly 54% of emissions from the livestock sector within the United States, with approximately 80% being associated with beef and dairy cattle. Supplementation of condensed tannins is a plausible method for improving environmental efficiency through the mitigation of enteric CH4 and shifting route of N excretion. During two experimental periods, 12 crossbred steers (236 ± 16 kg) were fed a roughage-based diet at maintenance level with the addition of QT at 0, 1.5, 3, and 4.5% of DM serving as dietary treatments. Following adaptation, feces were collected and gas fluxes measured using vented static chamber technique with manure incubated on the soil surface at two locations, College Station and Stephenville, during two periods corresponding to winter and spring. The daily flux of CO2 was influenced by soil moisture and temperature (r = 0.34; P < 0.01), whereas CH4 and N2O were associated with soil moisture. Cumulative CO2 and gross CO2 equivalent (CO2e) exhibited a dietary treatment effect at College Station (P ≤ 0.01), with a linear reduction with increased dietary QT. At both locations, we observed significance or tendencies for period effects for CO2, CH4, N2O, and CO2e (P ≤ 0.07) with period 2 having higher gas production. Within certain environments, QT supplementation could potentially reduce manure gas emissions, but additional investigation into animal variation is required.
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Giudicessi, John R., Matthew Schram, J. Martijn Bos, Conner D. Galloway, Jacqueline B. Shreibati, Patrick W. Johnson, Rickey E. Carter et al. "Artificial Intelligence–Enabled Assessment of the Heart Rate Corrected QT Interval Using a Mobile Electrocardiogram Device". Circulation 143, n.º 13 (30 de março de 2021): 1274–86. http://dx.doi.org/10.1161/circulationaha.120.050231.
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Background: Heart rate–corrected QT interval (QTc) prolongation, whether secondary to drugs, genetics including congenital long QT syndrome, and/or systemic diseases including SARS-CoV-2–mediated coronavirus disease 2019 (COVID-19), can predispose to ventricular arrhythmias and sudden cardiac death. Currently, QTc assessment and monitoring relies largely on 12-lead electrocardiography. As such, we sought to train and validate an artificial intelligence (AI)–enabled 12-lead ECG algorithm to determine the QTc, and then prospectively test this algorithm on tracings acquired from a mobile ECG (mECG) device in a population enriched for repolarization abnormalities. Methods: Using >1.6 million 12-lead ECGs from 538 200 patients, a deep neural network (DNN) was derived (patients for training, n = 250 767; patients for testing, n = 107 920) and validated (n = 179 513 patients) to predict the QTc using cardiologist-overread QTc values as the “gold standard”. The ability of this DNN to detect clinically-relevant QTc prolongation (eg, QTc ≥500 ms) was then tested prospectively on 686 patients with genetic heart disease (50% with long QT syndrome) with QTc values obtained from both a 12-lead ECG and a prototype mECG device equivalent to the commercially-available AliveCor KardiaMobile 6L. Results: In the validation sample, strong agreement was observed between human over-read and DNN-predicted QTc values (−1.76±23.14 ms). Similarly, within the prospective, genetic heart disease–enriched dataset, the difference between DNN-predicted QTc values derived from mECG tracings and those annotated from 12-lead ECGs by a QT expert (−0.45±24.73 ms) and a commercial core ECG laboratory [10.52±25.64 ms] was nominal. When applied to mECG tracings, the DNN’s ability to detect a QTc value ≥500 ms yielded an area under the curve, sensitivity, and specificity of 0.97, 80.0%, and 94.4%, respectively. Conclusions: Using smartphone-enabled electrodes, an AI DNN can predict accurately the QTc of a standard 12-lead ECG. QTc estimation from an AI-enabled mECG device may provide a cost-effective means of screening for both acquired and congenital long QT syndrome in a variety of clinical settings where standard 12-lead electrocardiography is not accessible or cost-effective.
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Hanly, P., A. Sienko e R. B. Light. "Effect of cyclooxygenase blockade on gas exchange and hemodynamics in Pseudomonas pneumonia". Journal of Applied Physiology 63, n.º 5 (1 de novembro de 1987): 1829–36. http://dx.doi.org/10.1152/jappl.1987.63.5.1829.
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Acute bilateral Pseudomonas aeruginosa pneumonia was induced in 10 anesthetized dogs, after which five dogs received intravenous indomethacin (2 mg/kg) (indomethacin group), whereas five others were infused with saline (2 ml/kg) (control group). Plasma levels of 6-ketoprostaglandin F1 alpha(6-keto-PGF1 alpha) and thromboxane B2 (TxB2), stable metabolites of prostacyclin (PGI2) and thromboxane A2 (TxA2), respectively, were measured by radioimmunoassay. Although TxB2 levels were not different before and after inoculation in either group, 6-keto-PGF1 alpha levels increased from their base-line value in each animal as pneumonia developed (indomethacin group: less than 100 to 330 +/- 90 pg/ml; control group: less than 100 to 630 +/- 300 pg/ml). Both prostaglandins fell to less than 100 pg/ml in each dog after indomethacin infusion, whereas they remained elevated in the control group after infusion of normal saline. Perfusion of consolidated lung regions (Qp/QT), measured with radioactive microspheres and expressed as a percent of total pulmonary blood flow, was dramatically reduced after indomethacin (35 +/- 3 to 16 +/- 1%) with consequent improvement in pulmonary shunt (Qs/QT: 30 +/- 8 to 18 +/- 6%) and arterial O2 tension (PaO2: 123 +/- 25 to 274 +/- 77 Torr). These parameters remained unchanged or deteriorated further in the control group after infusion of saline. Three additional dogs with Pseudomonas pneumonia were studied in which the indomethacin-induced reduction in Qp/QT was substantially but not completely reversed by intravenous infusion of PGI2.(ABSTRACT TRUNCATED AT 250 WORDS)
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Bougherara, Brahim, e Jacques Giacomoni. "Existence of mild solutions for a singular parabolic equation and stabilization". Advances in Nonlinear Analysis 4, n.º 2 (1 de maio de 2015): 123–34. http://dx.doi.org/10.1515/anona-2015-0002.
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AbstractIn this paper, we study the existence and the uniqueness of a positive mild solution for the following singular nonlinear problem with homogeneous Dirichlet boundary conditions: (St) ∂tu - Δpu = u -δ + f(x,u) in (0,T) × Ω =: QT, u = 0 on (0,T) × ∂Ω, u > 0 in QT, u(0,x) = u0 ≥ 0 in Ω, where Ω stands for a regular bounded domain of ℝN, Δpu is the p-Laplacian operator defined by Δpu = div(|∇u|p-2|∇u|) 1 < p < ∞, δ > 0 and T > 0. The nonlinear term f : Ω × ℝ → ℝ is a bounded below Carathéodory function and nonincreasing with respect to the second variable (for a.e. x ∈ Ω). We prove for any initial positive data u0 ∈ $\overline{{\mathcal {D}}(A)}^{L^\infty }$ the existence of a mild solution to (St). Then, we deduce some stabilization results for problem (St) in L∞(Ω) when p ≥ 2. This complements some results obtained in [J. Differential Equations 252 (2012), 5042–5075] stated with the additional restriction δ < 2 + 1/(p - 1).
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Kang, Dongwoo, Elizabeth Ludwig, David Jaworowicz, Hannah Huang, Jill Fiedler-Kelly, Jorge Cortes, Siddhartha Ganguly et al. "Concentration–QTc analysis of quizartinib in patients with relapsed/refractory acute myeloid leukemia". Cancer Chemotherapy and Pharmacology 87, n.º 4 (8 de janeiro de 2021): 513–23. http://dx.doi.org/10.1007/s00280-020-04204-y.
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Abstract Purpose This analysis evaluated the relationship between concentrations of quizartinib and its active metabolite AC886 and QT interval corrected using Fridericia’s formula (QTcF) in patients with relapsed/refractory acute myeloid leukemia (AML) treated in the phase 3 QuANTUM-R study (NCT02039726). Methods The analysis dataset included 226 patients with AML. Quizartinib dihydrochloride was administered as daily doses of 20, 30, and 60 mg. Nonlinear mixed-effects modeling was performed using observed quizartinib and AC886 concentrations and time-matched mean electrocardiogram measurements. Results Observed QTcF increased with quizartinib and AC886 concentrations; the relationship was best described by a nonlinear maximum effect (Emax) model. The predicted mean increase in QTcF at the maximum concentration of quizartinib and AC886 associated with 60 mg/day was 21.1 ms (90% CI, 18.3–23.6 ms). Age, body weight, sex, race, baseline QTcF, QT-prolonging drug use, hypomagnesemia, and hypocalcemia were not significant predictors of QTcF. Hypokalemia (serum potassium < 3.5 mmol/L) was a statistically significant covariate affecting baseline QTcF, but no differences in ∆QTcF (change in QTcF from baseline) were predicted between patients with versus without hypokalemia at the same quizartinib concentration. The use of concomitant QT-prolonging drugs did not increase QTcF further. Conclusion QTcF increase was dependent on quizartinib and AC886 concentrations, but patient factors, including sex and age, did not affect the concentration–QTcF relationship. Because concomitant strong cytochrome P450 3A (CYP3A) inhibitor use significantly increases quizartinib concentration, these results support the clinical recommendation of quizartinib dose reduction in patients concurrently receiving a strong CYP3A inhibitor. Clinical Trial Registration NCT02039726 (registered January 20, 2014).
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Güney, Ahmet Yasin, Fatih Şap, Beray Selver Eklioğlu, Mehmet Burhan Oflaz, Mehmet Emre Atabek e Tamer Baysal. "Investigation of the effect of epicardial adipose tissue thickness on cardiac conduction system in children with type 1 diabetes mellitus". Journal of Pediatric Endocrinology and Metabolism 33, n.º 6 (22 de maio de 2020): 713–20. http://dx.doi.org/10.1515/jpem-2020-0001.
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AbstractObjectivesInvestigation of the association between epicardial adipose tissue thickness (EATT) and P-wave dispersion (Pd), QT dispersion (QTd), corrected QT dispersion (QTcd) and Tp-e interval in children with Type 1 Diabetes Mellitus (T1DM) was aimed.MethodsForty-one children with T1DM and 41 age- and gender-matched healthy children were included in the study. Demographical characteristics of all cases were examined. In echocardiography; in addition to conventional echocardiographic measurements, end-systolic EATT was measured from right ventricular free wall. In electrocardiogram; Pd, QTd, QTcd and Tp-e interval durations, as well as Tp-e/QT and Tp-e/QTc ratios were calculated. Correlation values between EATT and electrocardiographic parameters were also noted.ResultsMean age of the patient group was determined to be 12.43 ± 3.04 years and that of the control group was determined to be 12.08 ± 2.56 years. There was no significant difference between the groups in regard to age, gender, body weight, height and body mass index. In the patient group; EATT, Pd, QTd, QTcd and Tp-e interval were determined to be significantly higher compared to the control group. In the patient group, no significant correlation was determined between EATT and Pd, QTd, QTcd and Tp-e. However, when both patient and control groups were evaluated together, a statistically significant positive correlation was determined between EATT and Pd, QTd, QTcd and Tp-e.ConclusionsIn children with T1DM, an increase in epicardial adipose tissue thickness and in risk of cardiac arrhythmias has been demonstrated. To reveal the possible unfavorable effects of EATT on cardiac conduction system in T1DM patients needs further studies.
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Marrodan, Ines, Itziar Rubio, Aitziber Buque, Aintzane Sancho, Natalia Fuente, Sergio Carrera, Mikel Arruti et al. "Preoperative chemoradiotherapy (QT-RT) with capecitabine and oxaliplatin (CAPOX) or capecitabine alone (CAP) in patients (PTS) with locally advanced rectal cancer (LARC)." Journal of Clinical Oncology 31, n.º 15_suppl (20 de maio de 2013): e14712-e14712. http://dx.doi.org/10.1200/jco.2013.31.15_suppl.e14712.
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e14712 Background: Preoperative concomitant QT-RT has shown to improve sphincter preservation and local control in LARC. We analyzed two cohorts of pts diagnosed of LARC treated with QT-RT with CAP or CAPOX. Methods: Pts with LARC (T3-T4 and/or N+) were treated with pelvic radiotherapy (45Gy in 25 fractions) concomitant with oxaliplatin (50mg/m2 day 1, 8, 22 and 29) and capecitabine (1650mg/m2 on days 1 to 14 and 22 to 35) or CAP (825mg/m2 bid for 5 days/week). Surgery was scheduled 6 weeks after completion QT-RT. Main end points assessed were: toxicity of preoperative chemotherapy, rate of sphincter preservation, pathological complete response (pCR) rate, and progression-free survival (PFS). Results: From Aug 2002 to Nov 2012, 254 pts with LARC were included; 53 pts received preoperative chemotherapy with CAP (cohort A) and 201 pts with CAPOX (cohort B). Median age: 65. Pts characteristics in cohort A: ECOG 0/1/2: 13/35/5; upper/mid/distal rectum 5/25/23; stage II/III 10/43. Pts characteristics in cohort B: ECOG 0/1/2: 48/149/4; upper/mid/distal rectum 29/105/67; stage II/III 27/174. 51 pts in cohort A (96.2%) and 192 (95%) in cohort B received full dose of preoperative QT-RT. Main toxicities in cohort A were diarrhea grade 2/3: 2/3 and neutropenia grade 2/3: 1/0; in cohort B were diarrhea grade 2/3: 42/24, neutropenia grade 2/3: 2/1 and neurotoxicity grade 1/2: 94/7. Surgery: 53 pts (100%) in cohort A and 198 pts (98.5%) in cohort B. Sphincter preservation and R0 resections were achieved in 58% pts and 98% pts respectively in cohort A, and 62% pts and 91.5% pts in cohort B. pCR was achieved in 11% pts in cohort A and 17% pts in cohort B. 3-year PFS and overall survival were 62% and 82% respectively in cohort A, and 75% and 83% in cohort B. Adding oxaliplatin in pts cT4/N- or N+ does not improve PFS (p=0.73). Downstaging in cohort A and B was achieved in 69.8% pts and 65% pts respectively. Conclusions: Combination QT-RT based in CAP or CAPOX is a well tolerated regimen and achieved encouring rates of pCR, R0 resection, sphincter preservation and tumor downstaging without differences in PFS in high risk pts with LARC.
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Sharafat, NI, M. Khalequzzaman, M. Akhtaruzzaman, AK Choudhury, S. Hasem, TA Choudhury, ABM Nurun Nobi, Shikder MR, M. Shaheen Kabir e AK Akanda. "Prolonged QTc Dispersion Correlates with Coronary Artery Disease in Acute ST Elevated Myocardial Infarction (STEMI)". Cardiovascular Journal 5, n.º 2 (29 de março de 2013): 173–81. http://dx.doi.org/10.3329/cardio.v5i2.14322.
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Background: It has been found that there is strong association of QT dispersion and QT dispersion ratio with extent and severity of coronary artery disease. Qualitative importance of QTc dispersion on the base line ECG in patients with MI is recognized clinically but quantification of this phenomenon is less commonly used in clinical practice, which might be a better independent risk predictor of this group of patients. Methods: A total of 100 patients were selected, Study populations sub-divided into two groups on the basis of QTc dispersion. In group I (comparison group): QTc dispersion is <60 milliseconds (msec) in group II (study group) : QTc dispersion e60milliseconds(msec). 50 patients in each group. QT dispersion was calculated on standard resting 12 lead ECGs. QT interval was measured from the beginning of the inscription of the QRS complex to the point at which the T wave returned to the isoelectric line. Angiographic severity of coronary artery disease was assessed by- Vessel score, Friesinger score and Leaman score. Interpretation of coronary angiogram was reviewed by at least two cardiologists. . Results: The mean vessel score for group I patients was 1.16±0.68 and that of group II patients was 2.30±0.64 and the mean difference was statistically significant (p<0.05). Patients those had single vessel involvement had mean QTc dispersion 57.05, patients those had double vessel disease mean QTc dispersion was 102.00 and patients those had triple vessel involvement had mean QTc dispersion 177.60. There was a strong positive correlation with the QTc dispersion and increasing number of vessel involvement (Pearsons correlation coefficient). The mean Friesinger score for group I patients was 4.84±2.56 and that of group II patients was 9.80±2.60. The mean difference was significantly (p<0.05) higher in group II patients. There was a strong positive correlation between the QTc dispersion and Leaman score (Pearsons correlation coefficient). In group I patients 56% had insignificant coronary artery disease and 44% had significant coronary artery disease defined by Friesinger index (n=100). In group II patients 6% had Insignificant coronary artery disease & had 94% significant coronary artery disease. Conclusion: QTc dispersion>60 ms had independent predictive value for the severity of coronary artery disease. The greater the QTc dispersion the higher the number of coronary artery involvement. We observed that there is a positive correlation between prolonged QT dispersion and coronary artery disease severity in terms of Vessel score, Friesinger score, Leaman score. DOI: http://dx.doi.org/10.3329/cardio.v5i2.14322 Cardiovasc. j. 2013; 5(2): 173-181
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Cook, Katherine, Thitinan Sraubol, Kristen Bova Campbell, Ahmad Mourad, Jonathan Stiber, John R. Perfect e Melissa Johnson. "QTc Prolongation in Patients Receiving Triazoles and Amiodarone". Open Forum Infectious Diseases 4, suppl_1 (2017): S84. http://dx.doi.org/10.1093/ofid/ofx163.031.
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Abstract Background Prolonged QT interval may lead to ventricular arrhythmias, torsade de pointes and sudden death. Triazole antifungals are often administered to inpatients with cardiac disease and with other QT prolonging drugs. Amiodarone is a commonly used antiarrhythmic that can prolong QT and be proarrhythmic but safety of co-administering these agents in the clinical setting is not known. Methods We conducted a retrospective, observational cohort study of adult inpatients at Duke University Medical Center who received concomitant systemic azoles and amiodarone from 2007 to 2013. Included subjects had ≥1 electrocardiogram (EKG) performed while receiving either agent alone within 1 month of starting concomitant therapy (baseline, BL) and ≥1 follow-up (FU) EKG after ≥2 days of concomitant therapy. A paired t-test was used to assess the maximum change in corrected QT interval (QTc, Bazett’s correction) from BL to FU. Logistic regression was used to evaluate predictors of FU QTc ≥500 ms (age, race, gender, and BL QTc ≥500 ms). Patient discharge diagnoses of ventricular arrhythmias or other cardiac events were reviewed to assess clinical outcome. Results Of 816 subjects identified, 252 had EKG results eligible for analysis. Azoles received were fluconazole (86.5%), voriconazole (11.5%), posaconazole (1.6%) or itraconazole (0.4%). Subjects were a median of 65 (IQR 25–88) years of age, 64.3% male and 78.6% Caucasian. Median duration of concomitant therapy was 7 days (IQR 4–11 days). Mean maximal change in QTc was +32 ms from BL (95% CI 26.2–38.6, P < 0.0001). 25.4 and 48.8% of subjects had a BL and FU QTc ≥500 ms, respectively. BL QTc ≥500 ms but not age, race, or gender was associated with FU QTc ≥500 ms (OR 6.32 95% CI 3.21–12.43). Thirty-day all-cause mortality was 26.2%. No cardiac events were apparent in relation to concomitant azole-amiodarone therapy. Conclusion Prolongation of the QTc interval was frequently observed in this cohort of patients receiving azoles and amiodarone. Clinical impact is challenging to assess in this critically ill, complex patient population but appears to be limited. Additional analyses are needed to further evaluate safety of azoles in the setting of other QTc prolonging agents. Disclosures All authors: No reported disclosures.
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jalalabadi, Narjes Zarei, Hamid Khederlou, Ahmadreza Rasouli, Razieh Anari, Fahime Moeini, Samaneh Parsa e Narges Sadeghi. "Evaluation of the Relationship between Serum Vitamin D and Morbidity and Mortality in Patients with COVID-19". Journal of Thoracic Disease and Cardiothoracic Surgery 2, n.º 3 (28 de setembro de 2021): 01–06. http://dx.doi.org/10.31579/2693-2156/026.
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Background: The COVID-19 can cause serious life-threatening complications. Vitamin D deficiency has been proposed to mediate the disease by some studies, however, there is a lack of sufficient data. Methods: In this descriptive-analytical study, 72 Iranian adult patients with COVID-19 were examined. At the beginning of hospitalization, serum levels of vitamin D were checked and patients were divided into four groups as vitamin D above normal, normal, insufficient, or deficient. The prognosis of patients has been evaluated based on serum levels of vitamin D and other underlying factors. Results: Only 30% of patients had normal vitamin D concentrations. Vitamin D status was associated with COVID-19 complications, but not with underlying diseases. In the multivariable logistic regression, COVID-19 prognosis was associated with being male, length of stay in an intensive care unit (ICU), need for intubation, acute respiratory disease syndrome (ARDS), and myocarditis. The serum vitamin D correlated with COVID-19 complications including ARDS, QT length, the requirement to ICU, and intubation. Conclusion: This study showed a mediating role for vitamin D in COVID-19 complications and identified the frequent complications in these patients and contributing variables exaggerating prognosis for health authorities to properly manage COVID-19 in hospitals. Further relevant examinations are highly encouraged.
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van Noord, Charlotte, Miriam C. J. M. Sturkenboom, Sabine M. J. M. Straus, Albert Hofman, Jan A. Kors, Jacqueline C. M. Witteman e Bruno H. Ch Stricker. "Serum glucose and insulin are associated with QTc and RR intervals in nondiabetic elderly". European Journal of Endocrinology 162, n.º 2 (fevereiro de 2010): 241–48. http://dx.doi.org/10.1530/eje-09-0878.
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AimsTo study whether nondiabetic persons with impaired fasting serum glucose and hyperinsulinemia have QTc/QT interval prolongation and RR interval shortening in the electrocardiogram (ECG), and whether these were associated with an increased risk of sudden cardiac death.MethodsThis study consisted of two analyses. First, a cross-sectional analysis was used as part of the population-based Rotterdam Study including 1050 men and 1520 women (≥55 years) without diabetes mellitus. Participants in round 3 of the Rotterdam Study for whom an ECG and fasting serum glucose and fasting insulin measurements were available were eligible for the study. Participants using digoxin or QTc-prolonging drugs and participants with left ventricular hypertrophy and left and right bundle branch block were excluded. The endpoints of the study were the lengths of the QTc, QT, and RR intervals. The associations were examined by means of linear regression analysis. Secondly, in all 6020 participants of the Rotterdam Study with an ECG, the associations between the QTc, QT, and RR intervals and sudden cardiac death were examined by means of Cox regression analysis.ResultsOverall, there was a significant association between impaired fasting serum glucose and the QTc interval with an increase of 2.6 ms (95% confidence interval (CI): 0.3; 5.0) in those with fasting glucose >6 mmol/l. Hyperinsulinemia was also associated with QTc prolongation (3.0 ms (0.8; 5.3)) in those with fasting insulin ≥100 pmol/l. Impaired fasting glucose (IFG) and hyperinsulinemia were significantly associated with a decrease of the RR interval (−33.7 ms (−48.8; −18.6) and −44.4 ms (−58.7; −30.0) respectively). Participants in the fourth quartile of the QTc and QT intervals had a significantly increased risk of sudden cardiac death compared to participants in the first quartile (hazard ratio (HR) 2.87 (95% CI: 2.02–4.06); HR 3.05 (1.99–4.67) respectively). Furthermore, there was a significant inverse association between the fourth quartile of the RR interval compared to the first quartile and the risk of sudden cardiac death (HR 0.49 (0.34–0.80)).ConclusionIn this population-based study, we demonstrated that IFG and hyperinsulinemia are associated with a significantly increased QTc interval and with significant shortening of the RR interval, the latter probably due to an increased sympathetic activity. In addition, we demonstrated that both a prolonged QTc interval and a shortened RR interval are associated with an increased risk of sudden cardiac death.
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Chivers, SC, T. Vasavan, M. Nandi, BR Hayes-Gill, IA Jayawardane, JM Simpson, C. Williamson, WP Fifer e M. Lucchini. "Measurement of the cardiac time intervals of the fetal ECG utilising a computerised algorithm: A retrospective observational study". JRSM Cardiovascular Disease 11 (janeiro de 2022): 204800402210962. http://dx.doi.org/10.1177/20480040221096209.
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Objective Establish whether the reliable measurement of cardiac time intervals of the fetal ECG can be automated and to address whether this approach could be used to investigate large datasets. Design Retrospective observational study. Setting Teaching hospitals in London UK, Nottingham UK and New York USA. Participants Singleton pregnancies with no known fetal abnormality. Methods Archived fetal ECG's performed using the MonicaAN24 monitor. A single ECG (PQRST) complex was generated from 5000 signal-averaged beats and electrical cardiac time intervals measured in an automated way and manually. Main Outcome measure Validation of a newly developed algorithm to measure the cardiac time intervals of the fetal ECG. Results 188/236 (79.7%) subjects with fECGs of suitable signal:noise ratio were included for analysis comparing manual with automated measurement. PR interval was measured in 173/188 (92%), QRS complex in 170/188 (90%) and QT interval in 123/188 (65.4%). PR interval was 107.6 (12.07) ms [mean(SD)] manual vs 109.11 (14.7) ms algorithm. QRS duration was 54.72(6.35) ms manual vs 58.34(5.73) ms algorithm. QT-interval was 268.93 (21.59) ms manual vs 261.63 (36.16) ms algorithm. QTc was 407.5(32.71) ms manual vs 396.4 (54.78) ms algorithm. The QRS-duration increased with gestational age in both manual and algorithm measurements. Conclusion Accurate measurement of fetal ECG cardiac time intervals can be automated with potential application to interpretation of larger datasets.
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Shimizu, Wataru, e Takeshi Aiba. "Notice of Retraction. Shimizu et al. Association of Genetic and Clinical Aspects of Congenital Long QT Syndrome With Life-Threatening Arrhythmias in Japanese Patients. JAMA Cardiol. 2019;4(3):246-254." JAMA Cardiology 6, n.º 6 (1 de junho de 2021): 727. http://dx.doi.org/10.1001/jamacardio.2021.1087.
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Sugimori, Hiroko, Fumihiro Tomoda, Tsutomu Koike, Masayo Hirose, Maiko Ohara, Hiroko Kurosaki, Satoshi Kagitani e Hiroshi Inoue. "226 PROLONGATION OF QT DISPERSION INDUCED BY MENTAL ARITHMETIC STRESS IN ESSENTIAL HYPERTENSIVES COMPLICATED WITH METABOLIC SYNDROME". Journal of Hypertension 30 (setembro de 2012): e69. http://dx.doi.org/10.1097/01.hjh.0000420052.11769.f4.
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Schreiber, L. R., C. R. Krause e J. S. Mayer. "Methomyl Phytotoxicity on Silver Maple, 1984". Insecticide and Acaricide Tests 10, n.º 1 (1 de janeiro de 1985): 299. http://dx.doi.org/10.1093/iat/10.1.299.
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Abstract Lathhouse grown, 18-24 inch seedlings were tested to investigate phytotoxicity of methomyl. Plants were grown in 2 qt pots using a 2:2:1 peat:perlite:soil mix. Pots were placed on a water porous mat which limited weed growth. Each treatment had 4 replications arranged in a CRD. The chemical was sprayed to run-off with a 2 gal hand pump sprayer (25 p.s.i.) at weekly intervals from 30 Jul to 20 Aug. No additional pesticides were applied, plants were hand watered as required. Temperatures in Jul were 2.6°F below normal, and temperatures in Aug were 0.5°F above normal. Phytotoxicity was evaluated as the percent total foliar area on 24 Aug.
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Krasteva, Vessela, Todor Stoyanov, Ramun Schmid e Irena Jekova. "Delineation of 12-Lead ECG Representative Beats Using Convolutional Encoder–Decoders with Residual and Recurrent Connections". Sensors 24, n.º 14 (17 de julho de 2024): 4645. http://dx.doi.org/10.3390/s24144645.
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The aim of this study is to address the challenge of 12-lead ECG delineation by different encoder–decoder architectures of deep neural networks (DNNs). This study compares four concepts for encoder–decoders based on a fully convolutional architecture (CED-Net) and its modifications with a recurrent layer (CED-LSTM-Net), residual connections between symmetrical encoder and decoder feature maps (CED-U-Net), and sequential residual blocks (CED-Res-Net). All DNNs transform 12-lead representative beats to three diagnostic ECG intervals (P-wave, QRS-complex, QT-interval) used for the global delineation of the representative beat (P-onset, P-offset, QRS-onset, QRS-offset, T-offset). All DNNs were trained and optimized using the large PhysioNet ECG database (PTB-XL) under identical conditions, applying an advanced approach for machine-based supervised learning with a reference algorithm for ECG delineation (ETM, Schiller AG, Baar, Switzerland). The test results indicate that all DNN architectures are equally capable of reproducing the reference delineation algorithm’s measurements in the diagnostic PTB database with an average P-wave detection accuracy (96.6%) and time and duration errors: mean values (−2.6 to 2.4 ms) and standard deviations (2.9 to 11.4 ms). The validation according to the standard-based evaluation practices of diagnostic electrocardiographs with the CSE database outlines a CED-Net model, which measures P-duration (2.6 ± 11.0 ms), PQ-interval (0.9 ± 5.8 ms), QRS-duration (−2.4 ± 5.4 ms), and QT-interval (−0.7 ± 10.3 ms), which meet all standard tolerances. Noise tests with high-frequency, low-frequency, and power-line frequency noise (50/60 Hz) confirm that CED-Net, CED-Res-Net, and CED-LSTM-Net are robust to all types of noise, mostly presenting a mean duration error < 2.5 ms when compared to measurements without noise. Reduced noise immunity is observed for the U-net architecture. Comparative analysis with other published studies scores this research within the lower range of time errors, highlighting its competitive performance.
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Scolarici, Michael J., Christopher Saddler, Jeannina Smith e Gregory Gauthier. "989. Isavuconazonium Sulfate Treatment of Blastomycosis: A Case Series". Open Forum Infectious Diseases 8, Supplement_1 (1 de novembro de 2021): S585. http://dx.doi.org/10.1093/ofid/ofab466.1183.
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Abstract Background Blastomyces fungi, endemic to the Ohio and Mississippi River Valleys, cause pneumonia and disseminated disease in both immunocompetent and immunocompromised patients. Prolonged antifungal therapy is commonly complicated by hepatic toxicity, QT prolongation, and drug interactions. Isavuconazonium sulfate is dosed once daily, does not prolong the QT interval, and has fewer drug interactions, but there is a paucity of data for its use in blastomycosis. Methods This case series of blastomycosis treated with isavuconazonium sulfate at the University of Wisconsin Hospital and Clinics from 2015 to December 2019 focuses on long term outcomes. Inclusion criteria were adults, that received at least one day of isavuconazole. Exclusion criteria was no blastomycosis diagnosis. Results Of 14 cases, median age was 53 years, 6/14 were female, 11/14 White, 2/14 Black, 1/14 Hmong, 6/14 had a solid organ transplant (4 renal, 1 heart, 1 bilateral lung), 1/14 on a TNF-alpha inhibitor (infliximab). Most cases, 9/14 had moderate severity illness requiring inpatient care, 2/14 required ICU level care, and 3/14 were outpatient. Most cases, 11/14, were initially treated with Liposomal Amphotericin B (LAMB) for a median duration of 14 days, 9/14 cases received itraconazole, 8/14 voriconazole, 1/14 posaconazole. Isavuconazonium sulfate was started after adverse drug effects with other azoles in 10/14 cases, prolonged QT interval in 3/14, drug interactions in 2/14, subtherapeutic azole levels in 2/14. Isavuconazonium sulfate was well tolerated and used for median duration of 255 (average 68% total treatment course). 3/14 cases had adverse reactions to isavuconazonium sulfate: nausea, rash, elevated liver enzymes. There was only one death during therapy from a fatal hemorrhagic stroke, and 2/14 cases were still on therapy at end of data collection. 11/14 were cured after treatment course. Conclusion This is the largest case series treating Blastomycosis with isavuconazonium sulfate, and it adds to the evidence that isavuconazonium sulfate can be safely used to treat pulmonary and disseminated blastomycosis. Prospective data is needed to compare isavuconazonium sulfate to other antifungals for the treatment of Blastomycosis. Disclosures All Authors: No reported disclosures
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Nelson, D. P., C. E. King, S. L. Dodd, P. T. Schumacker e S. M. Cain. "Systemic and intestinal limits of O2 extraction in the dog". Journal of Applied Physiology 63, n.º 1 (1 de julho de 1987): 387–94. http://dx.doi.org/10.1152/jappl.1987.63.1.387.
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When systemic delivery of O2 (QO2 = QT X CaO2, where QT is cardiac output and CaO2 is arterial O2 content) is reduced by bleeding, the systemic O2 extraction ratio [ER = (CaO2 - CVO2)/CaO2, where CVO2 is venous O2 content] increases until a critical limit is reached below which O2 uptake (VO2) becomes limited by O2 delivery. During hypovolemia, reflex increases in mesenteric arterial tone may preferentially reduce gut blood flow so that the onset of O2 supply dependence occurs in the gut before other regions. We compared the critical O2 delivery (QO2c) and critical extraction ratio (ERc) of whole body and an isolated segment (30–50 g) of small bowel in seven anesthetized paralyzed dogs ventilated with room air. Systemic QO2 was reduced in stages by controlled hemorrhage as arterial O2 content was maintained, and systemic and gut VO2 and QO2 were measured at each stage. Body QO2c was 7.9 +/- 1.9 ml X kg-1 X min-1 (ERc = 0.69 +/- 0.12), whereas gut O2 supply dependency occurred when gut QO2 was 34.3 +/- 11.3 ml X min-1 X kg gut wt-1 (ERc = 0.63 +/- 0.09). O2 supply dependency in the gut occurred at a higher systemic QO2 (9.7 +/- 2.7) than whole-body QO2c (P less than 0.05). The extraction ratio at the final stage (maximal ER) was less in the gut (0.80 +/- 0.05) than whole body (0.87 +/- 0.06). Thus during reductions in systemic QO2, gut VO2 was maintained by increases in gut extraction of O2.(ABSTRACT TRUNCATED AT 250 WORDS)
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Yadav, Priyanka, Vikram Yogi, Vijender Kumar, Lal Chand Yadav e Narendra Yadav. "Analysis of the Impact of Low Tunnel Technology on Farm Income of Bottle Gourd Growers in the Bikaner District of Rajasthan, India". Journal of Scientific Research and Reports 30, n.º 11 (14 de novembro de 2024): 742–48. http://dx.doi.org/10.9734/jsrr/2024/v30i112601.
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A field survey was conducted on farmers of Bikaner district to analyze of impact of low tunnel technology on farm income of bottle gourd growers with low tunnel technology and open field in Bikaner district. A total of 60 farmers was selected randomly i.e. 30 farmers with low tunnel technology and 30 farmers without low tunnel technology. The primary data was collected from the selected cultivators using the personal interview method. A partial budgeting technique was used for the impact of low tunnel technology. Partial Budgeting was used to calculate the economic impact of a single technology adoption. The result showed that the total operational cost in low tunnel technology is ₹ 123783.23 per ha and in open field total operational cost is ₹ 80883.23 per ha. In low tunnel technology 27.66 percent cost incurred in human labour followed by seed cost with 10.94 percent, while in open field it was 25.56 percent and 13.85 percent respectively. The gross return in low tunnel technology was ₹ 350000.00 per ha, in the open field ₹ 160000.00 per ha, the net return in low tunnel technology was ₹ 226216.77 per ha and ₹ 79116.77 per ha in the open field. The benefit-cost ratio of low tunnel bottle gourd production was 2.82 and in the open field, it was 1.97. In low tunnel technology, the added cost is ₹ 26822.26 per ha and the added return is ₹ 190000.00 per ha. In low tunnel technology bottle gourd production average yield is 250 Qt per ha and in open field average yield is 200 Qt per ha.