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1
Ichinose, Masashi, Mitsuru Saito, Narihiko Kondo, and Takeshi Nishiyasu. "Time-dependent modulation of arterial baroreflex control of muscle sympathetic nerve activity during isometric exercise in humans." American Journal of Physiology-Heart and Circulatory Physiology 290, no. 4 (April 2006): H1419—H1426. http://dx.doi.org/10.1152/ajpheart.00847.2005.
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We investigated the time-dependent modulation of arterial baroreflex (ABR) control of muscle sympathetic nerve activity (MSNA) that occurs during isometric handgrip exercise (IHG). Thirteen healthy subjects performed a 3-min IHG at 30% maximal voluntary contraction, which was followed by a period of imposed postexercise muscle ischemia (PEMI). The ABR control of MSNA (burst incidence and strength and total activity) was evaluated by analyzing the relationship between spontaneous variations in diastolic arterial pressure (DAP) and MSNA during supine rest, at each minute of IHG, and during PEMI. We found that 1) the linear relations between DAP and MSNA variables were shifted progressively rightward until the third minute of IHG (IHG3); 2) 2 min into IHG (IHG2), the DAP-MSNA relations were shifted upward and were shifted further upward at IHG3; 3) the sensitivity of the ABR control of total MSNA was increased at IHG2 and increased further at IHG3; and 4) during PEMI, the ABR operating pressure was slightly higher than at IHG2, and the sensitivity of the control of total MSNA was the same as at IHG2. During PEMI, the DAP-burst strength and DAP-total MSNA relations were shifted downward from the IHG3 level to the IHG2 level, whereas the DAP-burst incidence relation remained at the IHG3 level. These results indicate that during IHG, ABR control of MSNA is modulated in a time-dependent manner. We suggest that this modulation of ABR function is one of the mechanisms underlying the progressive increase in blood pressure and MSNA during the course of isometric exercise.
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McGinn, Ryan, Brendan Swift, Konrad Binder, Daniel Gagnon, and Glen P. Kenny. "Do metaboreceptors alter heat loss responses following dynamic exercise?" American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 306, no. 1 (January 1, 2014): R82—R89. http://dx.doi.org/10.1152/ajpregu.00364.2013.
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Metaboreceptor activation during passive heating is known to influence cutaneous vascular conductance (CVC) and sweat rate (SR). However, whether metaboreceptors modulate the suppression of heat loss following dynamic exercise remains unclear. On separate days, before and after 15 min of high-intensity treadmill running in the heat (35°C), eight males underwent either 1) no isometric handgrip exercise (IHG) or ischemia (CON), 2) 1 min IHG (60% of maximum, IHG), 3) 1 min IHG followed by 2 min of ischemia (IHG+OCC), 4) 2 min of ischemia (OCC), or 5) 1 min IHG followed by 2 min of ischemia with application of lower body negative pressure (IHG+LBNP). SR (ventilated capsule), cutaneous blood flow (Laser-Doppler), and mean arterial pressure (Finometer) were measured continuously before and after dynamic exercise. Following dynamic exercise, CVC was reduced with IHG exercise ( P < 0.05) and remained attenuated with post-IHG ischemia during IHG+OCC relative to CON (39 ± 2 vs. 47 ± 6%, P < 0.05). Furthermore, the reduction in CVC was exacerbated by application of LBNP during post-IHG ischemia (35 ± 3%, P < 0.05) relative to IHG+OCC. SR increased during IHG exercise ( P < 0.05) and remained elevated during post-IHG ischemia relative to CON following dynamic exercise (0.94 ± 0.15 vs. 0.53 ± 0.09 mg·min−1·cm−2, P < 0.05). In contrast, application of LBNP during post-IHG ischemia had no effect on SR (0.93 ± 0.09 mg·min−1·cm−2, P > 0.05) relative to post-IHG ischemia during IHG+OCC. We show that CVC is reduced and that SR is increased by metaboreceptor activation following dynamic exercise. In addition, we show that the metaboreflex-induced loading of the baroreceptors can influence the CVC response, but not the sweating response.
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McGowan, Cheri L., Andrew S. Levy, Philip J. Millar, Juan C. Guzman, Carlos A. Morillo, Neil McCartney, and Maureen J. MacDonald. "Acute vascular responses to isometric handgrip exercise and effects of training in persons medicated for hypertension." American Journal of Physiology-Heart and Circulatory Physiology 291, no. 4 (October 2006): H1797—H1802. http://dx.doi.org/10.1152/ajpheart.01113.2005.
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Previous work from our laboratory demonstrated that isometric handgrip (IHG) training improved local, endothelium-dependent vasodilation in medicated hypertensives [McGowan CL (PhD Thesis), 2006; McGowan et al. Physiologist 47: 285, 2004]. We investigated whether changes in the capacity of smooth muscle to dilate (regardless of endothelial factors) influenced this training-induced change, and we examined the acute vascular responses to a single bout of IHG. Seventeen subjects performed four 2-min unilateral IHG contractions at 30% of maximal voluntary effort, three times a week for 8 wk. Pre- and posttraining, brachial artery flow-mediated dilation (FMD, an index of endothelium-dependent vasodilation) and nitroglycerin-mediated maximal vasodilation (an index of endothelium-independent vasodilation) were measured in the exercised arm by using ultrasound before and immediately after acute IHG exercise. IHG training resulted in improved resting brachial FMD ( P < 0.01) and no change in nitroglycerin-mediated maximal vasodilation. Pre- and posttraining, brachial artery FMD decreased following an acute bout of IHG exercise (normalized to peak shear rate, pre-, before IHG exercise: 0.01 ± 0.002, after IHG exercise: 0.008 ± 0.002%/s−1; post-, before IHG exercise: 0.020 ± 0.003, after IHG exercise: 0.010 ± 0.003%/s−1; P < 0.01). Posttraining, resting brachial artery FMD improved yet nitroglycerin-mediated maximal vasodilation was unchanged in persons medicated for hypertension. This suggests that the training-induced improvements in the resting brachial artery FMD were not due to underlying changes in the forearm vasculature. Acute IHG exercise attenuated brachial artery FMD, and although this impairment may be interpreted as hazardous to medicated hypertensives with already dysfunctional endothelium, the effects appear transient as repeated exposure to the IHG stimulus improved resting endothelium-dependent vasodilation.
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Cosio, Claudia. "Inorganic Mercury and Methyl-Mercury Uptake and Effects in the Aquatic Plant Elodea nuttallii: A Review of Multi-Omic Data in the Field and in Controlled Conditions." Applied Sciences 10, no. 5 (March 6, 2020): 1817. http://dx.doi.org/10.3390/app10051817.
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(1) Background: Mercury is a threat for the aquatic environment. Nonetheless, the entrance of Hg into food webs is not fully understood. Macrophytes are both central for Hg entry in food webs and are seen as good candidates for biomonitoring and bioremediation; (2) Methods: We review the knowledge gained on the uptake and effects of inorganic Hg (IHg) and methyl-Hg (MMHg) in the macrophyte Elodea nuttallii found in temperate freshwaters; (3) Results: E. nuttallii bioaccumulates IHg and MMHg, but IHg shows a higher affinity to cell walls. At the individual level, IHg reduced chlorophyll, while MMHg increased anthocyanin. Transcriptomics and metabolomics in shoots revealed that MMHg regulated a higher number of genes than IHg. Proteomics and metabolomics in cytosol revealed that IHg had more effect than MMHg; (4) Conclusions: MMHg and IHg show different cellular toxicity pathways. MMHg’s main impact appears on the non-soluble compartment, while IHg’s main impact happens on the soluble compartment. This is congruent with the higher affinity of IHg with dissolved OM (DOM) or cell walls. E. nuttallii is promising for biomonitoring, as its uptake and molecular responses reflect exposure to IHg and MMHg. More generally, multi-omics approaches identify cellular toxicity pathways and the early impact of sublethal pollution.
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Bowman, R. M., M. Dantus, and A. H. Zewail. "Femtochemistry of the reaction: IHgI*→[IHg…I]‡*→HgI+I." Chemical Physics Letters 156, no. 2-3 (March 1989): 131–37. http://dx.doi.org/10.1016/s0009-2614(89)87108-8.
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Javidi, Mohsen, Sajad Ahmadizad, Hassan Argani, Abdolrahman Najafi, Khosrow Ebrahim, Narges Salehi, Yasaman Javidi, Linda S. Pescatello, Alireza Jowhari, and Daniel A. Hackett. "Effect of Lower- versus Higher-Intensity Isometric Handgrip Training in Adults with Hypertension: A Randomized Controlled Trial." Journal of Cardiovascular Development and Disease 9, no. 9 (August 30, 2022): 287. http://dx.doi.org/10.3390/jcdd9090287.
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This study compared the effects of lower- versus higher-intensity isometric handgrip exercise on resting blood pressure (BP) and associated clinical markers in adults with hypertension. Thirty-nine males were randomly assigned to one of three groups, including isometric handgrip at 60% maximal voluntary contraction (IHG-60), isometric handgrip at 30% IHG-30, or a control group (CON) that had been instructed to continue with their current activities of daily living. The volume was equated between the exercise groups, with IHG-60 performing 8 × 30-s contractions and IHG-30 performing 4 × 2-min contractions. Training was performed three times per week for 8 weeks. Resting BP (median [IQR]), flow-mediated dilation, heart rate variability, and serum markers of inflammation and oxidative stress were measured pre- and post-intervention. Systolic BP was significantly reduced for IHG-60 (−15.5 mmHg [−18.75, −7.25]) and IHG-30 (−5.0 mmHg [−7.5, −3.5]) compared to CON (p < 0.01), but no differences were observed between both the exercise groups. A greater reduction in diastolic BP was observed for IHG-60 (−5.0 mmHg [−6.0, −4.25] compared to IHG-30 (−2.0 mmHg [−2.5, −2.0], p = 0.042), and for both exercise groups compared to CON (p < 0.05). Flow-mediated dilation increased for both exercise groups versus CON (p < 0.001). IHG-30 had greater reductions in interleukin-6 and tumor necrosis factor-α compared to the other groups (p < 0.05) and CON (p = 0.018), respectively. There was a reduction in Endothelin-1 for IHG-60 compared to CON (p = 0.018). Both the lower- and higher-intensity IHG training appear to be associated with reductions in resting BP and improvements in clinical markers of inflammation and oxidative stress.
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Zhang, Zhen, Jing Li, Lei Yang, Rongping Chen, Rui Yang, Hua Zhang, Dehong Cai, and Hong Chen. "The Cytotoxic Role of Intermittent High Glucose on Apoptosis and Cell Viability in Pancreatic Beta Cells." Journal of Diabetes Research 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/712781.
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Objectives. Glucose fluctuations are both strong predictor of diabetic complications and crucial factor for beta cell damages. Here we investigated the effect of intermittent high glucose (IHG) on both cell apoptosis and proliferation activity in INS-1 cells and the potential mechanisms.Methods. Cells were treated with normal glucose (5.5 mmol/L), constant high glucose (CHG) (25 mmol/L), and IHG (rotation per 24 h in 11.1 or 25 mmol/L) for 7 days. Reactive oxygen species (ROS), xanthine oxidase (XOD) level, apoptosis, cell viability, cell cycle, and expression of cyclinD1, p21, p27, and Skp2 were determined.Results. We found that IHG induced more significant apoptosis than CHG and normal glucose; intracellular ROS and XOD levels were more markedly increased in cells exposed to IHG. Cells treated with IHG showed significant decreased cell viability and increased cell proportion in G0/G1 phase. Cell cycle related proteins such as cyclinD1 and Skp2 were decreased significantly, but expressions of p27 and p21 were increased markedly.Conclusions. This study suggested that IHG plays a more toxic effect including both apoptosis-inducing and antiproliferative effects on INS-1 cells. Excessive activation of cellular stress and regulation of cyclins might be potential mechanism of impairment in INS-1 cells induced by IHG.
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Voegeli, Christoph. "A CASE STUDY OF KNOWLEDGE MANAGEMENT PRACTICES AT THE INTERCONTINENTAL HOTELS’ GROUP." International Journal of Tourism & Hospitality Reviews 8, no. 1 (February 11, 2021): 17–29. http://dx.doi.org/10.18510/ijthr.2021.812.
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Purpose of the study: This study aims to gain an understanding of how (and if) the InterContinental Hotels Group (IHG) manages knowledge to create value.
Methodology: Publicly available data about the IHG were assessed using Pawlowski and Bick’s (2015) Global Knowledge Management Framework (GKMFW) to determine the extent to which the IHG is implementing knowledge management (KM). Four experts reviewed the findings for validation.
Main findings: Knowledge management (KM) practices are used by the IHG at a basic level. Data collected in this study indicate that the IHG is not connecting KM processes in its strategy. This research highlights that the IHG and potentially other hotel companies could integrate KM to enhance their performance.
Applications of this study: The study’s findings are important for hotel industry stakeholders (academics, hotel executives, owners, etc.), assisting them to better understand “hotel KM”. Stakeholders are encouraged to implement holistic and purposeful KM programs (i.e., a framework), potentially delivering more value to their organizations.
Novelty/Originality of this study: This study is the first attempt to investigate KM activities in one major standard-setting hotel company (SSHC), as defined by Boardman and Barbato (2008). It highlights the limitations in hotel-specific KM research and the limited way in which KM is being applied in the InterContinental Hotels Group (IHG). It not only identifies a gap in the literature about KM in the hospitality industry but starts to fill this gap.
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Wilson, Thad E., Damian J. Dyckman, and Chester A. Ray. "Determinants of skin sympathetic nerve responses to isometric exercise." Journal of Applied Physiology 100, no. 3 (March 2006): 1043–48. http://dx.doi.org/10.1152/japplphysiol.00579.2005.
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Exercise-induced increases in skin sympathetic nerve activity (SSNA) are similar between isometric handgrip (IHG) and leg extension (IKE) performed at 30% of maximal voluntary contraction (MVC). However, the precise effect of exercise intensity and level of fatigue on this relationship is unclear. This study tested the following hypotheses: 1) exercise intensity and fatigue level would not affect the magnitude of exercise-induced increase in SSNA between IHG and IKE, and 2) altering IHG muscle mass would also not affect the magnitude of exercise-induced increase in SSNA. In protocol 1, SSNA (peroneal microneurography) was measured during baseline and during the initial and last 30 s of isometric exercise to volitional fatigue in 12 subjects who randomly performed IHG and IKE bouts at 15, 30, and 45% MVC. In protocol 2, SSNA was measured in eight subjects who performed one-arm IHG at 30% MVC with the addition of IHG of the contralateral arm in 10-s intervals for 1 min. Exercise intensity significantly increased SSNA responses during the first 30 s of IHG (34 ± 13, 70 ± 11, and 92 ± 13% change from baseline) and IKE (30 ± 17, 69 ± 12, and 76 ± 13% change from baseline) for 15, 30, and 45% MVC. During the last 30 s of exercise to volitional fatigue, there were no significant differences in SSNA between exercise intensities or limb. SSNA did not significantly change between one-arm and two-arm IHG. Combined, these data indicate that exercise-induced increases in SSNA are intensity dependent in the initial portion of isometric exercise, but these differences are eliminated with the development of fatigue. Moreover, the magnitude of exercise-induced increase in SSNA responses is not dependent on either muscle mass involved or exercising limb.
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Goulopoulou, Styliani, Bo Fernhall, and Jill A. Kanaley. "Developmental Changes in Hemodynamic Responses and Cardiovagal Modulation during Isometric Handgrip Exercise." International Journal of Pediatrics 2010 (2010): 1–11. http://dx.doi.org/10.1155/2010/153780.
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The purpose of this study was to examine differences in pressor response and cardiovagal modulation during isometric handgrip exercise (IHG) between children and adults. Beat-to-beat heart rate (HR) and blood pressure were measured in 23 prepubertal children and 23 adults at baseline and during IHG. Cardiovagal modulation was quantified by analysis of HR variability. Mean arterial pressure responses to IHG were greater in adults compared to children (P<.05) whereas there were no group differences in HR responses (P>.05). Children had a greater reduction in cardiovagal modulation in response to IHG compared to adults (P<.05). Changes in mean arterial pressure during IHG were correlated with baseline cardiovagal modulation and force produced during isometric contraction (P<.05). In conclusion, differences in pressor reflex response between children and adults cannot be solely explained by differences in autonomic modulation and appear to be associated with factors contributing to the force produced during isometric contraction.
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Beauvais-Flück, Rebecca, Vera Slaveykova, and Claudia Cosio. "Molecular Effects of Inorganic and Methyl Mercury in Aquatic Primary Producers: Comparing Impact to A Macrophyte and A Green Microalga in Controlled Conditions." Geosciences 8, no. 11 (October 29, 2018): 393. http://dx.doi.org/10.3390/geosciences8110393.
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Mercury (Hg) remains hazardous in aquatic environments, because of its toxicity and high biomagnification in food webs. In phytoplankton and macrophytes, Hg compounds at high concentration have been reported to affect the growth, photosynthesis, and nutrient metabolism, as well as to induce oxidative stress and damage. Here, we reviewed the recent knowledge gained on cellular toxicity of inorganic and methyl Hg (IHg; MeHg) in aquatic primary producers at more relevant environmental concentrations, with a particular focus on omics data. In addition, we compared a case study conducted with transcriptomic on the green microalga Chlamydomonas reinhardtii and the macrophyte Elodea nuttallii. At lower concentrations, IHg and MeHg influenced similar gene categories, including energy metabolism, cell structure, and nutrition. In addition, genes involved in the cell motility in the microalgae, and in hormone metabolism in the macrophyte were regulated. At equivalent intracellular concentration, MeHg regulated more genes than IHg supporting a higher molecular impact of the former. At the organism level in C. reinhardtii, MeHg increased reactive oxygen species, while both IHg and MeHg increased photosynthesis efficiency, whereas in E. nuttallii MeHg induced anti-oxidant responses and IHg reduced chlorophyll content. Data showed differences, according to species and characteristics of life cycle, in responses at the gene and cellular levels, but evidenced a higher molecular impact of MeHg than IHg and different cellular toxicity pathways in aquatic primary producers.
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Okamoto, Takanobu, and Yuto Hashimoto. "Decreases in Arterial Stiffness and Wave Reflection after Isometric Handgrip Training Are Associated with Improvements in Cognitive Function in Older Adults." International Journal of Environmental Research and Public Health 19, no. 15 (August 4, 2022): 9585. http://dx.doi.org/10.3390/ijerph19159585.
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This study aimed to investigate whether decreases in arterial stiffness and wave reflection after isometric handgrip (IHG) training improve cognitive function in older adults. Twenty-two older adults (mean age ± standard error: 75 ± 2 years) were randomly assigned to either a group that performed IHG training (IHG group, n = 11) or a sedentary control group (CON group, n = 11). The IHG exercise comprised four unilateral 2-minute isometric contractions at 30% of maximal voluntary contraction using a programmed handgrip dynamometer with 1-minute rest periods, performed 5 days per week for 8 weeks. Carotid pulse wave velocity (cPWV) and carotid augmentation index (cAIx) were measured, and the trail-making test (TMT) parts A (TMT-A) and B (TMT-B) were performed before (baseline) and after 8 weeks of training in both groups. After 8 weeks of training, cPWV, cAIx, TMT-A, and TMT-B were significantly reduced in the IHG group (p < 0.05). Significant positive correlations were found between the amount of change in cPWV and cAIx and that in TMT-A (p < 0.05 each). In addition, positive correlation trends were observed between the amount of change in cPWV and cAIx and that in TMT-B (p = 0.06, p = 0.05, respectively). The results of the present study suggest that IHG training-induced decreases in arterial stiffness and wave reflection are associated with improvements in cognitive function in older adults.
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Kuipers, Nathan T., Charity L. Sauder, Matthew L. Kearney, and Chester A. Ray. "Changes in forearm muscle temperature alter renal vascular responses to isometric handgrip." American Journal of Physiology-Heart and Circulatory Physiology 293, no. 6 (December 2007): H3432—H3439. http://dx.doi.org/10.1152/ajpheart.00822.2007.
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The purpose of the present study was to examine the effect of heating and cooling the forearm muscles on renal vascular responses to ischemic isometric handgrip (IHG). It was hypothesized that heating and cooling the forearm would augment and attenuate, respectively, renal vascular responses to IHG. Renal vascular responses to IHG were studied during forearm heating at 39°C ( n = 15, 26 ± 1 yr) and cooling at 26°C ( n = 12, 26 ± 1 yr). For a control trial, subjects performed the experimental protocol while the forearm was normothermic (∼34°C). Muscle temperature (measured by intramuscular probe) was controlled by changing the temperature of water cycling through a water-perfused sleeve. The experimental protocol was as follows: 3 min at baseline, 1 min of ischemia, ischemic IHG to fatigue, and 2 min of postexercise muscle ischemia. At rest, renal artery blood velocity (RBV; Doppler ultrasound) and renal vascular conductance (RVC = RBV/mean arterial blood pressure) were not different between normothermia and the two thermal conditions. During ischemic IHG, there were greater decreases in RBV and RVC in the heating trial. However, RBV and RVC were similar during postexercise muscle ischemia during heating and normothermia. RVC decreased less during cooling than in normothermia while the subjects performed the ischemic IHG protocol. During postexercise muscle ischemia, RVC was greater during cooling than in normothermia. These results indicate that heating augments mechanoreceptor-mediated renal vasoconstriction whereas cooling blunts metaboreceptor-mediated renal vasoconstriction.
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Somers, V. K., K. C. Leo, R. Shields, M. Clary, and A. L. Mark. "Forearm endurance training attenuates sympathetic nerve response to isometric handgrip in normal humans." Journal of Applied Physiology 72, no. 3 (March 1, 1992): 1039–43. http://dx.doi.org/10.1152/jappl.1992.72.3.1039.
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Recent evidence indicates that muscle ischemia and activation of the muscle chemoreflex are the principal stimuli to sympathetic nerve activity (SNA) during isometric exercise. We postulated that physical training would decrease muscle chemoreflex stimulation during isometric exercise and thereby attenuate the SNA response to exercise. We investigated the effects of 6 wk of unilateral handgrip endurance training on the responses to isometric handgrip (IHG: 33% of maximal voluntary contraction maintained for 2 min). In eight normal subjects the right arm underwent exercise training and the left arm sham training. We measured muscle SNA (peroneal nerve), heart rate, and blood pressure during IHG before vs. after endurance training (right arm) and sham training (left arm). Maximum work to fatigue (an index of training efficacy) was increased by 1,146% in the endurance-trained arm and by only 40% in the sham-trained arm. During isometric exercise of the right arm, SNA increased by 111 +/- 27% (SE) before training and by only 38 +/- 9% after training (P less than 0.05). Endurance training did not significantly affect the heart rate and blood pressure responses to IHG. We also measured the SNA response to 2 min of forearm ischemia after IHG in five subjects. Endurance training also attenuated the SNA response to postexercise forearm ischemia (P = 0.057). Sham training did not significantly affect the SNA responses to IHG or forearm ischemia. We conclude that endurance training decreases muscle chemoreflex stimulation during isometric exercise and thereby attenuates the sympathetic nerve response to IHG.
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Shi, Xiao-li, Yue-zhong Ren, and Jing Wu. "Intermittent High Glucose Enhances Apoptosis in INS-1 Cells." Experimental Diabetes Research 2011 (2011): 1–7. http://dx.doi.org/10.1155/2011/754673.
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To investigate the effect of intermittent high glucose (IHG) and sustained high glucose (SHG) on inducingβ-cell apoptosis and the potential involved mechanisms, INS-1 beta cells were incubated for 72 h in the medium containing different glucose concentrations: control (5.5 mmol/L), SHG (33.3 mmol/L), and IHG (5.5 mmol/L and 33.3 mmol/L glucose alternating every 12 h). Cell viability, apoptosis rate, and oxidative-stress markers were determined. The results showed that the apoptosis induced by IHG was more obvious than that by SHG. Simultaneously, the intracellular level of oxidative stress was more significantly increased in INS-1 cells exposed to IHG. These findings suggest that intermittent high glucose could be more deleterious toβ-cell than a constant high concentration of glucose, this may be due to the aggravation of oxidative stress triggered by intermittent high glucose.
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Iellamo, F., R. L. Hughson, F. Castrucci, J. M. Legramante, G. Raimondi, G. Peruzzi, and G. Tallarida. "Evaluation of spontaneous baroreflex modulation of sinus node during isometric exercise in healthy humans." American Journal of Physiology-Heart and Circulatory Physiology 267, no. 3 (September 1, 1994): H994—H1001. http://dx.doi.org/10.1152/ajpheart.1994.267.3.h994.
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The purpose of this study was to 1) evaluate the baroreflex (BR) modulation of the sinus node during isometric exercise in humans by analyzing the variations in pulse interval (PI) in response to beat-by-beat spontaneous changes in systolic arterial pressure (SAP), thus avoiding external intervention to alter arterial pressure (AP); and to 2) evaluate the specific influence of muscle chemoreflex on the SAP-PI relationship. Sixteen healthy males were studied during rest, handgrip at 30% of maximum voluntary contraction [isometric handgrip (IHG)], post-IHG arrested forearm circulation (AFC), and recovery. AP and PI were measured continuously and noninvasively. A BR response was defined by series of at least three consecutive beats in which SAP and PI of the following beat either increased or decreased in a linear fashion. In nine subjects, forearm (FVR) and calf vascular resistances (CVR) were determined. Mean slope (by linear regression) of SAP-PI sequences did not significantly differ between rest, IHG, and AFC (14.1 +/- 2.0, 12.2 +/- 1.6, and 13.2 +/- 1.4 ms/mmHg, respectively), i.e., BR sensitivity was unchanged. IHG resulted in a rightward shift of the regression line relating SAP to PI. The shift was maintained during AFC, when PI returned to control and AP fell slightly but remained significantly elevated. CVR, which did not change during IHG, significantly increased during AFC, whereas FVR increased during both IHG and AFC, but not significantly. The data indicate that arterial BR is "reset" to a higher operating point during isometric exercise. Muscle chemoreflex appears to be partially involved in this modification.(ABSTRACT TRUNCATED AT 250 WORDS)
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Capano, Manuela, Cécile Miramont, Lisa Shindo, Frédéric Guibal, Christian Marschal, Bernd Kromer, Thibaut Tuna, and Edouard Bard. "Onset of the Younger Dryas Recorded with 14C at Annual Resolution in French Subfossil Trees." Radiocarbon 62, no. 4 (November 25, 2019): 901–18. http://dx.doi.org/10.1017/rdc.2019.116.
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ABSTRACTSubfossil trees with their annual rings constitute the most accurate and precise archive to calibrate the radiocarbon (14C) method. The Holocene part of the IntCal curve is based on tree-ring chronologies, absolutely dated by dendrochronological matching. For the Northern Hemisphere, the absolute curve starts at 12,325 cal BP. For the early part of the Younger Dryas (YD) climatic event (≈ 12,850–11,650 cal BP), there are only a few floating dendrochronological sequences, mainly from Switzerland and France. We present new 14C results from subfossil trees (Pinus sylvestris L.) collected from the Barbiers site (southeast French Alps). The dendrochronological series covers 416 years, corresponding to the onset of the YD period. In order to date our sequence, we matched it with the 14C record based on kauri trees from New Zealand. The Barbiers data were first averaged at the same decadal resolution as the kauri record. Statistical comparison of the different averaging options and matching techniques enables dating the Barbiers sequence to 13,008–12,594 ±10 cal BP, which thus includes the boundary between the Allerød and YD events. The new Barbiers record allows to calculate the 14C inter-hemispheric gradient (14C-IHG) during the period overlapping the kauri sequence. For the optimal dating option, the mean 14C-IHG is 37 yr with a standard deviation (SD) of 21 yr based on 43 decadal estimations (−6‰ with SD of 2‰). The 14C-IHG record exhibits minimal values, down to zero, between 12,960–12,840 cal BP. Excluding these minima leads to an average 14C-IHG of 45 yr with a SD of 14 yr based on 33 decadal values, in agreement with observations for the last two millennia. The Barbiers record suggests a 14C-IHG increase between the end of the Allerød period (IHG of 37 yr with SD of 14 yr) and the early part of the YD (IHG of 48 yr with SD of 14 yr), which is compatible with previously reported drop of deep-water convection in the North-Atlantic and the associated increase in wind-driven upwelling in the Southern Ocean.
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Ray, Chester A., and Thad E. Wilson. "Comparison of skin sympathetic nerve responses to isometric arm and leg exercise." Journal of Applied Physiology 97, no. 1 (July 2004): 160–64. http://dx.doi.org/10.1152/japplphysiol.00699.2003.
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Measurement of skin sympathetic nerve activity (SSNA) during isometric exercise has been previously limited to handgrip. We hypothesized that isometric leg exercise due to the greater muscle mass of the leg would elicit greater SSNA responses than arm exercise because of presumably greater central command and muscle mechanoreceptor activation. To compare the effect of isometric arm and leg exercise on SSNA and cutaneous end-organ responses, 10 subjects performed 2 min of isometric knee extension (IKE) and handgrip (IHG) at 30% of maximal voluntary contraction followed by 2 min of postexercise muscle ischemia (PEMI) in a normothermic environment. SSNA was recorded from the peroneal nerve. Cutaneous vascular conductance (laser-Doppler flux/mean arterial pressure) and electrodermal activity were measured within the field of cutaneous afferent discharge. Heart rate and mean arterial pressure significantly increased by 16 ± 3 and 23 ± 3 beats/min and by 22 ± 2 and 27 ± 3 mmHg from baseline during IHG and IKE, respectively. Heart rate and mean arterial pressure responses were significantly greater during IKE compared with IHG. SSNA increased significantly and comparably during IHG and IKE (52 ± 20 and 50 ± 13%, respectively). During PEMI, SSNA and heart rate returned to baseline, whereas mean arterial pressure remained significantly elevated (Δ12 ± 2 and Δ13 ± 2 mmHg from baseline for IHG and IKE, respectively). Neither cutaneous vascular conductance nor electrodermal activity was significantly altered by either exercise or PEMI. These results indicate that, despite cardiovascular differences in response to IHG and IKE, SSNA responses are similar at the same exercise intensity. Therefore, the findings suggest that relative effort and not muscle mass is the main determinant of exercise-induced SSNA responses in humans.
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Crandall, C. G., J. Musick, J. P. Hatch, D. L. Kellogg, and J. M. Johnson. "Cutaneous vascular and sudomotor responses to isometric exercise in humans." Journal of Applied Physiology 79, no. 6 (December 1, 1995): 1946–50. http://dx.doi.org/10.1152/jappl.1995.79.6.1946.
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To identify whether isometric handgrip exercise (IHG) affects cutaneous vasoconstrictor and/or active vasodilator activities, seven subjects (6 men and 1 woman) performed 30% maximal voluntary contraction of a forearm under normothermic (1 bout) and hyperthermic (2 bouts) conditions. Skin blood flow was indexed by laser-Doppler flowmetry at a contralateral forearm site at which adrenergic vasoconstrictor function was blocked by iontophoresis of bretylium tosylate (BT) and therefore only has active vasodilation as a mechanism for reflex control. Skin blood flow was also monitored at an adjacent untreated site. Cutaneous vascular conductance (CVC) was calculated from the flow signal and noninvasive blood pressure. CVC was normalized to the value obtained from maximal vasodilation at that site. Sweat rate (SR) was measured at the same locations. During normothermia, IHG did not affect CVC at the control or BT-treated sites, nor did IHG affect SR (P > 0.05). The second bout of IHG in hyperthermia evoked significant reductions in CVC at the untreated (69.4 +/- 3.4 to 58.9 +/- 2.5% of maximum, P < 0.05) and BT-treated sites (75.4 +/- 6.1 to 64.4 +/- 6.2% of maximum, P < 0.05), whereas SR significantly increased (0.62 +/- 0.16 to 0.70 +/- 0.17 mg.cm-2.min-1, P < 0.05). These findings uniquely show that, in hyperthermia, IHG reduces active vasodilator activity while at the same time sudomotor activity is increasing. This suggests independent control of these effectors.
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Ray, Chester A. "Interaction between vestibulosympathetic and skeletal muscle reflexes on sympathetic activity in humans." Journal of Applied Physiology 90, no. 1 (January 1, 2001): 242–47. http://dx.doi.org/10.1152/jappl.2001.90.1.242.
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Evidence from animals indicates that skeletal muscle afferents activate the vestibular nuclei and that both vestibular and skeletal muscle afferents have inputs to the ventrolateral medulla. The purpose of the present study was to investigate the interaction between the vestibulosympathetic and skeletal muscle reflexes on muscle sympathetic nerve activity (MSNA) and arterial pressure in humans. MSNA, arterial pressure, and heart rate were measured in 17 healthy subjects in the prone position during three experimental trials. The three trials were 2 min of 1) head-down rotation (HDR) to engage the vestibulosympathetic reflex, 2) isometric handgrip (IHG) at 30% maximal voluntary contraction to activate skeletal muscle afferents, and 3) HDR and IHG performed simultaneously. The order of the three trials was randomized. HDR and IHG performed alone increased total MSNA by 46 ± 16 and 77 ± 24 units, respectively ( P < 0.01). During the HDR plus IHG trial, MSNA increased 142 ± 38 units ( P < 0.01). This increase was not significantly different from the sum of the individual trials (130 ± 41 units). This finding was also observed with mean arterial pressure (sum = 21 ± 2 mmHg and HDR + IHG = 22 ± 2 mmHg). These findings suggest that there is an additive interaction for MSNA and arterial pressure when the vestibulosympathetic and skeletal muscle reflexes are engaged simultaneously in humans. Therefore, no central modulation exists between these two reflexes with regard to MSNA output in humans.
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Paull, Gabrielle, Sheila Dervis, Ryan McGinn, Baies Haqani, Andreas D. Flouris, Narihiko Kondo, and Glen P. Kenny. "Muscle metaboreceptors modulate postexercise sweating, but not cutaneous blood flow, independent of baroreceptor loading status." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 309, no. 11 (December 1, 2015): R1415—R1424. http://dx.doi.org/10.1152/ajpregu.00287.2015.
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We examined whether sustained changes in baroreceptor loading status during prolonged postexercise recovery can alter the metaboreceptors' influence on heat loss. Thirteen young males performed a 1-min isometric handgrip exercise (IHG) at 60% maximal voluntary contraction followed by 2 min of forearm ischemia (to activate metaboreceptors) before and 15, 30, 45, and 60 min after a 15-min intense treadmill running exercise (>90% maximal heart rate) in the heat (35°C). This was repeated on three separate days with continuous lower body positive (LBPP, +40 mmHg), negative (LBNP, −20 mmHg), or no pressure (Control) from 13- to 65-min postexercise. Sweat rate (ventilated capsule; forearm, chest, upper back) and cutaneous vascular conductance (CVC; forearm, upper back) were measured. Relative to pre-IHG levels, sweating at all sites increased during IHG and remained elevated during ischemia at baseline and similarly at 30, 45, and 60 min postexercise (site average sweat rate increase during ischemia: Control, 0.13 ± 0.02; LBPP, 0.12 ± 0.02; LBNP, 0.15 ± 0.02 mg·min−1·cm−2; all P < 0.01), but not at 15 min (all P > 0.10). LBPP and LBNP did not modulate the pattern of sweating to IHG and ischemia (all P > 0.05). At 15-min postexercise, forearm CVC was reduced from pre-IHG levels during both IHG and ischemia under LBNP only (ischemia: 3.9 ± 0.8% CVCmax; P < 0.02). Therefore, we show metaboreceptors increase postexercise sweating in the middle to late stages of recovery (30–60 min), independent of baroreceptor loading status and similarly between skin sites. In contrast, metaboreflex modulation of forearm but not upper back CVC occurs only in the early stages of recovery (15 min) and is dependent upon baroreceptor unloading.
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Andrade, Aparecido Ribeiro de, Juliane Bereze, Rosana Martins dos Santos, and João Anésio Bednarz. "Disponibilidade térmica para diferentes culturas agrícolas em região de clima subtropical úmido obtida através da utilização de índice bioclimático." Geosul 32, no. 64 (September 18, 2017): 66–83. http://dx.doi.org/10.5007/2177-5230.2017v32n64p66.
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Existem vários sistemas de unidades bioclimáticas além dos graus-dia, embora sua utilização e limitação ainda sejam pouco conhecidas na agricultura contemporânea. Diante disso, este trabalho objetivou avaliar o desempenho do Índice Heliotérmico de Geslin (IHG) para diferentes culturas agrícolas difundidas em área de clima subtropical úmido, tendo como estudo de caso o município Guarapuava(PR). A comparação entre o IHG ideal em cada fase produtiva e o IHG efetivamente ocorrido durante as safras de 2008 a 2013 possibilitou identificar distintos níveis de influência da disponibilidade térmica para o cultivo agrícola na região. Os dados foram cedidos pelo Instituto Agronômico do Paraná – IAPAR e analisados através de estatística clássica, que serviu de base para a escolha do índice utilizado.
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Efimov, V. B., L. P. Mezhov-Deglin, C. D. Dewhurst, A. V. Lokhov, and V. V. Nesvizhevsky. "Neutron Scattering on Impurity Nanoclusters in Gel Samples." Advances in High Energy Physics 2015 (2015): 1–4. http://dx.doi.org/10.1155/2015/808212.
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Results of recent SANS experiments with impurity-helium gel (IHG) samples in He-II are presented. We estimate the mean size of the impurity nanoparticles that form the frame of the IHG samples and discuss the possibility to use IHG samples for the production of ultracold neutrons (UCNs) in He-II cooled to the temperature of a few mK, as well as the reflection of UCNs at any temperature. Our results indicate that the most promising materials for these purposes might be the heavy water gel samples with the mean sizes of D2O clusters ofd~8 nm and the heavy alcohol gel samples with the mean sizes of clusters ofd~15 nm.
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Nunes, Paula Beatriz de Oliveira, Maria Karolina Martins Ferreira, Deborah Ribeiro Frazão, Leonardo Oliveira Bittencourt, Victória dos Santos Chemelo, Márcia Cristina Freitas Silva, Armando Lopes Pereira-Neto, et al. "Effects of inorganic mercury exposure in the alveolar bone of rats: an approach of qualitative and morphological aspects." PeerJ 10 (January 26, 2022): e12573. http://dx.doi.org/10.7717/peerj.12573.
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Background In comparison to organic mercury (MeHg), the environmental inorganic mercury (IHg) can be found in some skin-lightening cosmestics were considered “harmless” for a long time. However, recent studies have shown that long-term exposure to low doses of IHg may affect biological systems. Therefore, this study investigated the effects of IHg long-term exposure to the alveolar bone of adult rats. Methods Adult Wistar rats were distributed in control and HgCl2 exposed (0.375 mg/kg/day). After 45 days, the rats were euthanized and both blood and hemimandibles were collected. Total blood Hg levels were measured and both inorganic and organic components of the alveolar bone were determined through XRD and ATR-FTIR. The microstructure of the alveolar bone was assessed by using micro-CT and the morphometric analysis was performed by using stereomicroscopy. Results Alterations in the physicochemical components of the alveolar bone of exposed animals were observed. The bone changes represented a tissue reaction at the microstructural level, such as bone volume increase. However, no significant dimensional changes (bone height) were observed. Conclusion Exposure to IHg at this dose can promote microstructural changes and alteration in the organic and inorganic components in the alveolar bone.
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Regnell, Olof, Tommy Hammar, Anders Helgée, and Bo Troedsson. "Effects of anoxia and sulfide on concentrations of total and methyl mercury in sediment and water in two Hg-polluted lakes." Canadian Journal of Fisheries and Aquatic Sciences 58, no. 3 (March 1, 2001): 506–17. http://dx.doi.org/10.1139/f01-001.
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Between May and December 1996, monthly samples of surface sediment (01 cm), settling matter, and water were taken at a shallow site and a deep site in each of two consecutive Hg-polluted riverine lakes. In the upper lake, the sediment was polluted also with cellulose fiber. Both hypolimnia turned anoxic, but sulfide was detected only in the upper lake. When sulfide appeared, hypolimnetic methyl mercury (MeHg) increased and reached 47 pM (9.4 ng·L1), whereas MeHg in the sediment below decreased. The increase in hypolimnetic inorganic Hg (IHg = total Hg MeHg), which reached a peak of 40 pM (8.0 ng·L1), was slower, possibly because mobilized IHg was methylated. In the lower lake, hypolimnetic MeHg and IHg increased less dramatically during summer stratification, reaching only 5 and 24 pM (1.0 and 4.8 ng·L1), respectively. There was no detectable concomitant decrease in sediment MeHg. In both lakes, MeHg appeared to increase simultaneously with total Fe and Mn in the hypolimnion, as did IHg in the lower lake. Our observations suggest that the presence of hydrous ferric and manganese oxides decreased the mobility of Hg in both lakes but increased MeHg production in the upper lake.
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Melo, Geiziane Leite Rodrigues, Milton Rocha Moraes, Weldson Ferreira Abreu, Rafael Reis Olher, Lysleine Alves Deus, Rodrigo Vanerson Passos Neves, Thiago dos Santos Rosa, et al. "Cardiovascular and nitric oxide response after maximal voluntary isometric contraction in adolescents with and without Down Syndrome." Research, Society and Development 11, no. 1 (January 13, 2022): e50011125342. http://dx.doi.org/10.33448/rsd-v11i1.25342.
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Este estudo teve como objetivo comparar as respostas cardiovasculares e de óxido nítrico (NO) à contração isométrica voluntária máxima (CIVM) com diferentes grupos musculares (leg press [LEP] e preensão manual isométrica [IHG]) de adolescentes com e sem síndrome de Down (SD). Alem de comparar a força IHG absoluta e relativa entre os grupos. Onze adolescentes com SD (14,1 ± 1,0 anos) e dez sem SD (13,7 ± 1,25 anos) realizaram duas sessões experimentais de exercícios LEP e IHG: 1) sessão de familiarização e 2) 3 tentativas x 5 segundos de contração na CIVM com 3- intervalo mínimo de descanso. A pressão arterial (PA), a frequência cardíaca (FC) e o NO foram coletados em repouso, imediatamente após a sessão de exercício e 10 minutos após o exercício. A dosagem de NO na saliva foi realizada pelo método colorimétrico de Griess. Não houve diferenças para respostas cardiovasculares e NO entre os grupos para CIVM. No entanto, o SD teve uma resposta cardiovascular menor, mas não significativamente, em repouso e após os testes de CIVM do que aqueles sem SD. O grupo SD apresentou maior concentração de NO em repouso, recuperação e após IHG quando comparado ao grupo não SD (P <0,05). Além disso, adolescentes com SD apresentaram menor nível de força de IHG absoluta e relativa quando comparados àqueles sem SD (P = 0,001). Indivíduos com SD apresentam menor resposta cardiovascular em repouso e após testes de CIVM e maior resposta de NO após o exercício quando comparados ao grupo sem SD.
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Miller, Kathleen B., Virginia M. Miller, Ronée E. Harvey, Sushant M. Ranadive, Michael J. Joyner, and Jill N. Barnes. "Augmented cerebral blood velocity in response to isometric handgrip exercise in women with a history of preeclampsia." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 317, no. 6 (December 1, 2019): R834—R839. http://dx.doi.org/10.1152/ajpregu.00280.2019.
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Preeclampsia (PE) is a hypertensive disorder of pregnancy described as a condition of excessive sympathoexcitation. PE places a woman at increased risk for lifelong hypertension and cognitive impairment. Cerebral blood velocity is blunted in response to a vasoactive stimulus in women with a history of PE. This study investigated how a sympathoexcitatory stimulus affects cerebral blood velocity in women with a history of PE. Middle cerebral artery blood velocity (MCAv) and beat-to-beat mean arterial blood pressure (MAP) were measured in postmenopausal women with a history of PE ( n = 21; age = 59 ± 5 yr) and a history of a normotensive pregnancy (NP; n = 27; age = 58 ± 4 yr), at baseline, during isometric handgrip to fatigue (IHG) followed by postexercise ischemia (PEI), and a recovery period (REC). Baseline MAP and MAP responses to IHG and PEI did not differ between groups. MCAv at baseline and throughout the stimulus was lower in PE women compared with NP women ( P < 0.05 for all). MCAv increased during IHG in both groups ( P < 0.05). This increase in MCAv was greater in PE compared with NP women during IHG and REC (IHG: PE 13 ± 2% vs. NP 9 ± 2%; REC: PE 3 ± 2% vs. NP −2 ± 2%; P < 0.05 for both). Thus, a history of PE is associated with low baseline cerebral blood velocity but an augmented response to a sympathoexcitatory stimulus. These changes in cerebral blood flow regulation may lead to an increased risk for cognitive impairment in women with a history of PE.
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Kondo, Narihiko, Shuji Yanagimoto, Takeshi Nishiyasu, and Craig G. Crandall. "Effects of muscle metaboreceptor stimulation on cutaneous blood flow from glabrous and nonglabrous skin in mildly heated humans." Journal of Applied Physiology 94, no. 5 (May 1, 2003): 1829–35. http://dx.doi.org/10.1152/japplphysiol.00810.2002.
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Given differences in sympathetic innervation to glabrous and nonglabrous skin, we tested the hypothesis that muscle metaboreceptor regulation of cutaneous vascular conductance (CVC) differs between these skin regions. Subjects ( n = 21) performed isometric handgrip exercise (IHG; 50% maximal voluntary contraction for 60 s), followed by 2 min of postexercise ischemia. Throughout IHG and postexercise ischemia, CVC was measured from glabrous (palm) and nonglabrous (forearm and chest) regions contralateral to the exercising arm. These procedures were conducted after the subjects had been exposed to an ambient temperature of 35°C and a relative humidity of 50% for 60 min. These thermal conditions were intended to cause slight increases in cutaneous blood flow via sympathetic withdrawal. Esophageal, sublingual, and mean skin temperatures did not change markedly during IHG or postexercise ischemia. During IHG, forearm CVC did not change, chest CVC increased slightly, and palm CVC decreased substantially (from 100 to 34.8 ± 3.5%; P = 0.001). During muscle metaboreceptor stimulation due to postexercise ischemia, CVC from nonglabrous regions returned to preexercise baselines, whereas CVC at the palm remained below preexercise baseline (68.2 ± 4.2%; P = 0.001 relative to preexercise baseline). These results indicate that in mildly heated humans muscle metaboreflex stimulation is capable of modulating CVC in glabrous, but not in nonglabrous, skin.
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Carter, Jason R., Charity L. Sauder, and Chester A. Ray. "Effect of morphine on sympathetic nerve activity in humans." Journal of Applied Physiology 93, no. 5 (November 1, 2002): 1764–69. http://dx.doi.org/10.1152/japplphysiol.00462.2002.
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There are conflicting reports for the role of endogenous opioids on sympathetic and cardiovascular responses to exercise in humans. A number of studies have utilized naloxone (an opioid-receptor antagonist) to investigate the effect of opioids during exercise. In the present study, we examined the effect of morphine (an opioid-receptor agonist) on sympathetic and cardiovascular responses at rest and during isometric handgrip (IHG). Eleven subjects performed 2 min of IHG (30% maximum) followed by 2 min of postexercise muscle ischemia (PEMI) before and after systemic infusion of morphine (0.075 mg/kg loading dose + 1 mg/h maintenance) or placebo (saline) in double-blinded experiments on separate days. Morphine increased resting muscle sympathetic nerve activity (MSNA; 17 ± 2 to 22 ± 2 bursts/min; P < 0.01) and increased mean arterial pressure (MAP; 87 ± 2 to 91 ± 2 mmHg; P < 0.02), but it decreased heart rate (HR; 61 ± 4 to 59 ± 3; P < 0.01). However, IHG elicited similar increases for MSNA, MAP, and HR between the control and morphine trial (drug × exercise interaction = not significant). Moreover, responses to PEMI were not different. Placebo had no effect on resting, IHG, and PEMI responses. We conclude that morphine modulates cardiovascular and sympathetic responses at rest but not during isometric exercise.
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Kaczmarzyk, Marcin, Aleksander Starakiewicz, and Aleksander Waśniowski. "Internal Heat Gains in a Lunar Base—A Contemporary Case Study." Energies 13, no. 12 (June 20, 2020): 3213. http://dx.doi.org/10.3390/en13123213.
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The Moon’s environmental conditions present limited opportunities for waste heat dissipation, so internal heat gains (IHG) are a key component of thermal balance in a lunar building. Despite the significant development in energy saving and energy storage technologies of the last thirty years, the issue of IHG in lunar buildings has not been readdressed since the early 1990s. This study is based on an inspection of internal heat sources conducted aboard LUNARES, the first European extraterrestrial analogue habitat. The equipment absent on LUNARES, but indispensable for an actual lunar base, was identified and accounted for, along with additional laboratory and maintenance equipment. Three main groups of internal heat sources were identified and studied in detail. Waste heat generated by electric devices was accounted for, along with occupational heat loads adjusted for lunar partial gravity conditions. Assuming a photovoltaic power source for the studied building, two alternative energy storage systems (ESS) were analysed as another source of waste heat. Depending on the time of lunar day and applied ESS, the nominal IHG were between 73 and 133 W/m2. The most significant internal heat sources in a lunar base are life support systems and potentially, regenerative fuel cells; thus, lithium–ion batteries were recommended for ESS. Within assumed parameter range, parametric study exhibited differences in IHG between 41.5 and 163 W/m2.
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Ray, Chester A., and Dario I. Carrasco. "Isometric handgrip training reduces arterial pressure at rest without changes in sympathetic nerve activity." American Journal of Physiology-Heart and Circulatory Physiology 279, no. 1 (July 1, 2000): H245—H249. http://dx.doi.org/10.1152/ajpheart.2000.279.1.h245.
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The purpose of this study was to determine whether isometric handgrip (IHG) training reduces arterial pressure and whether reductions in muscle sympathetic nerve activity (MSNA) mediate this drop in arterial pressure. Normotensive subjects were assigned to training ( n = 9), sham training ( n = 7), or control ( n = 8) groups. The training protocol consisted of four 3-min bouts of IHG exercise at 30% of maximal voluntary contraction (MVC) separated by 5-min rest periods. Training was performed four times per week for 5 wk. Subjects' resting arterial pressure and heart rate were measured three times on 3 consecutive days before and after training, with resting MSNA (peroneal nerve) recorded on the third day. Additionally, subjects performed IHG exercise at 30% of MVC to fatigue followed by muscle ischemia. In the trained group, resting diastolic (67 ± 1 to 62 ± 1 mmHg) and mean arterial pressure (86 ± 1 to 82 ± 1 mmHg) significantly decreased, whereas systolic arterial pressure (116 ± 3 to 113 ± 2 mmHg), heart rate (67 ± 4 to 66 ± 4 beats/min), and MSNA (14 ± 2 to 15 ± 2 bursts/min) did not significantly change following training. MSNA and cardiovascular responses to exercise and postexercise muscle ischemia were unchanged by training. There were no significant changes in any variables for the sham training and control groups. The results indicate that IHG training is an effective nonpharmacological intervention in lowering arterial pressure.
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Verhaaren, H. A., R. M. Schieken, P. Schwartz, M. Mosteller, D. Matthys, H. Maes, G. Beunen, R. Vlietinck, and R. Derom. "Cardiovascular reactivity in isometric exercise and mental arithmetic in children." Journal of Applied Physiology 76, no. 1 (January 1, 1994): 146–50. http://dx.doi.org/10.1152/jappl.1994.76.1.146.
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In children, we studied noninvasively the cardiovascular stress responses, including changes over time of systolic blood pressure (SBP), heart rate (HR), and stroke volume (SV) in isometric handgrip (IHG) and mental arithmetic. Specifically, we asked whether 1) these cardiovascular stress responses were different for the two stress conditions in children, 2) these responses differed in boys and girls, and 3) the anthropometric variables related to these stress responses. SV differed significantly between IHG and mental arithmetic over the entire stress period. This may reflect higher systemic vascular resistance during IHG. HR in boys was lower than in girls over the entire period of stress in both stress tests. This observation cannot be attributed to differences in conditioning, because this should not influence responses to isometric or mental stress. A larger left ventricular mass was related to higher SVs. A marked relationship was found between HR and SBP and between HR and SV. No relationship was found between SBP and SV.
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Yin, Xueyao, Fenping Zheng, Qianqian Pan, Saifei Zhang, Dan Yu, Zhiye Xu, and Hong Li. "Glucose fluctuation increased hepatocyte apoptosis under lipotoxicity and the involvement of mitochondrial permeability transition opening." Journal of Molecular Endocrinology 55, no. 3 (December 2015): 169–81. http://dx.doi.org/10.1530/jme-15-0101.
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Oxidative stress is considered to be an important factor in producing lethal hepatocyte injury associated with nonalcoholic fatty liver disease (NAFLD). Glucose fluctuation, more pronounced in patients with diabetes, has been recognized as an even stronger oxidative stress inducer than the sustained hyperglycemia. Here, we investigated the role of glucose variability in the development of the NAFLD based on hepatocyte apoptosis and possible mechanisms. To achieve this goal we studied C57BL/6J mice that were maintained on a high fat diet (HFD) and injected with glucose (3 g/kg) twice daily to induce intermittent high glucose (IHG). We also studied hepatic L02 cells incubated with palmitic acid (PA) to induce steatosis. The following experimental groups were compared: normal glucose (NG), sustained high glucose (SHG) and IHG with or without PA. We found that, although hepatic enzyme levels and liver lipid deposition were comparable between HFD mice injected with glucose or saline, the glucose injected mice displayed marked hepatocyte apoptosis and inflammation, accompanied by increased lipid peroxide in liver.In vitro, in the presence of PA, IHG increased L02 cell apoptosis and oxidative stress and produced pronounced mitochondrial dysfunction relative to the NG and SHG groups. Furthermore, treatment with the mitochondrial permeability transition (MPT) inhibitor, cyclosporin A (1.5 μmol/l), prevented mitochondrial dysfunction, oxidative stress and hepatocyte apoptosis. Our data suggests that IHG under lipotoxicity might contribute to the development of NAFLD by increasing oxidative stress and hepatocyte apoptosis via MPT and its related mitochondrial dysfunction.
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Fernandes, Saul Estevam. "Os engarrafadores dos espaços ou a disputa pela produção espacial norte rio-grandense e cearense durante na retomada da questão de limites entre os sócios do IHGA-CE e o IHG-RN." Revista Espacialidades 9, no. 01 (November 5, 2016): 140–65. http://dx.doi.org/10.21680/1984-817x.2016v9n01id17776.
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O presente trabalho discute como a retomada da Questão de Limites entre os estados brasileiros do Rio Grande do Norte e Ceará condicionou a produção territorial por meio dos intelectuais que compunham o Instituto Histórico, Geográfico e Antropológico do Ceará (IHGA-CE) e o Instituto Histórico e Geográfico do Rio Grande do Norte (IHG-RN). Problematizo as tentativas dos intelectuais cearenses e potiguares em dizerem os territórios dos dois estados por meios de cronistas, memórias, descrições, comemorações e mapas.
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Chiang, Jason, Aditi Bagchi, Xiaoyu Li, Sandeep K. Dhanda, Jie Huang, Soniya N. Pinto, Edgar Sioson, et al. "HGG-03. HIGH-GRADE GLIOMA IN YOUNG CHILDREN IS HISTOLOGICALLY, MOLECULARLY, AND CLINICALLY DIVERSE—RESULTS FROM THE SJYC07 TRIAL AND INSTITUTIONAL EXPERIENCE." Neuro-Oncology 25, Supplement_1 (June 1, 2023): i38—i39. http://dx.doi.org/10.1093/neuonc/noad073.152.
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Abstract BACKGROUND High-grade gliomas (HGG) in young children pose a challenge due to favorable but unpredictable outcomes. While retrospective studies have broadened our understanding of tumor biology, prospective data regarding outcomes and molecular predictors is lacking. METHODS Young children (0-5 years) histologically diagnosed with HGG and enrolled on the SJYC07 trial or treated at St Jude Children’s Research Hospital from November 2007 to December 2020 were included. DNA methylation, whole genome (WGS), whole exome (WES), and RNA (RNA-seq) sequencing were performed on available samples and these data were integrated with standard histopathological tests to yield a diagnosis. Clinical characteristics and pre-operative imaging were analyzed. RESULTS Fifty-six children (0.0-4.4 years) were identified. Integrated molecular and histopathological analysis split the tumors into four categories: infant-type hemispheric glioma (IHG), HGG, low-grade glioma (LGG), and other-central nervous system (CNS) tumors (i.e., CNS embryonal tumors, CNS sarcomas, neuroepithelial tumors). IHG was the most prevalent (N=22), occurred in the youngest patients (median age 0.4 years; 0-4.4 years), and commonly harbored receptor tyrosine kinase gene fusions (7 ALK, 2 ROS1, 3 NTRK1/2/3, 4 MET). The 5-year event-free (EFS) and overall survival (OS) for IHG was 53.13% (95% CI: 35.52 -79.47) and 90.91% (95%CI: 79.66-100.00) vs. 0.0% and 16.67% (95% CI: 2.78-99.74%) for HGG (p= 0.0043, 0.00013). EFS and OS were not different between IHG and LGG (p=0.95, 0.43). Imaging review of HGG, LGG , IHG and Other CNS tumors showed that IHGs are associated with circumscribed margins (p=0.0047), hemispheric location (p=0.0010), and hemorrhage (p=0.0149). CONCLUSIONS HGG in young children is not a single-entity and is best defined by an integrated histopathological and molecular diagnosis. While patients with IHGs display good survival, as compared to other pediatric HGGs, they still suffer severe treatment-related morbidities. Therefore, prompt consideration for reduced adjuvant and molecularly targeted therapies is warranted.
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Friesen, Brian J., Martin P. Poirier, Dallon T. Lamarche, Andrew W. D’Souza, Jung-Hyun Kim, Sean R. Notley, and Glen P. Kenny. "Postexercise whole-body sweating increases during muscle metaboreceptor activation in young men." Applied Physiology, Nutrition, and Metabolism 43, no. 4 (April 2018): 423–26. http://dx.doi.org/10.1139/apnm-2017-0675.
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We assessed the effect of metaboreceptor activation on whole-body evaporative heat loss (WB-EHL) in 12 men (aged 24 ± 4 years) in the early-to-late stages of a 60-min exercise recovery in the heat. Metaboreceptor activation induced by 1-min isometric-handgrip (IHG) exercise followed by 5-min forearm ischemia to trap metabolites increased WB-EHL by 25%–31% and 26%–34% during the ischemic period relative to IHG-only and control (natural recovery only), respectively, throughout recovery. We show that metaboreceptor activation enhances WB-EHL in recovery.
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Saad, Adham R., Dan P. Stephens, Lee Ann T. Bennett, Nisha Charkoudian, Wojciech A. Kosiba, and John M. Johnson. "Influence of isometric exercise on blood flow and sweating in glabrous and nonglabrous human skin." Journal of Applied Physiology 91, no. 6 (December 1, 2001): 2487–92. http://dx.doi.org/10.1152/jappl.2001.91.6.2487.
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The distribution of the reflex effects of isometric exercise on cutaneous vasomotor and sudomotor function is not clear. We examined the effects of isometric exercise by different muscle masses on skin blood flow (SkBF) and sweat rate (SR) in nonglabrous skin and in glabrous skin. The latter contains arteriovenous anastomoses (AVAs), which cause large fluctuations in SkBF. SkBF was measured by laser-Doppler flowmetry (LDF) and reported as cutaneous vascular conductance (CVC; LDF/mean arterial pressure). SR was measured by capacitance hygrometry. LDF and SR were measured at the sole, palm, forearm, and ventral leg during separate bouts of isometric handgrip (IHG) and isometric leg extension (ILE). CVC and its standard deviation decreased significantly during IHG and ILE in the palm and sole ( P < 0.05) but not in the forearm or leg ( P > 0.05). Only palmar SR increased significantly during IHG and ILE ( P < 0.05). We conclude that the major reflex influences of isometric exercise on the skin include AVAs and palmar sweat glands and that this is true for both arm and leg exercise.
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Picelli de Azevedo, Maria Gabriela, Silvano Salgueiro Geraldes, Paula Bilbau Sant’Anna, Beatriz Poloni Batista, Suellen Rodrigues Maia, Reiner Silveira de Moraes, Elizabeth Moreira dos Santos Schmidt, et al. "C-reactive protein concentrations are higher in dogs with stage IV chronic kidney disease treated with intermittent hemodialysis." PLOS ONE 17, no. 9 (September 22, 2022): e0274510. http://dx.doi.org/10.1371/journal.pone.0274510.
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In chronic kidney disease dogs, the inflammatory process increases C-reactive protein concentrations. This study aimed to determine C-reactive protein serum concentrations in stage IV chronic kidney disease dogs treated with intermittent hemodialysis. A prospective cohort study was conducted with 23 dogs allocated into three groups: control group (CG, n = 7), intermittent hemodialysis group (IHG, n = 8) and clinical treatment group (CTG, n = 8), both comprised of stage IV chronic kidney disease dogs. One blood sample from CG (initial evaluation) and two samples from IHG and CTG (first- and last-moment) were obtained to determine C-reactive protein concentration, total leukocytes, platelets, erythrocytes, total plasma protein, serum albumin, urea, creatinine, and phosphorus. C-reactive protein was higher in IHG compared to CG in the first- and last-moments (p <0.001) and compared to CTG in the first-moment (p = 0.0406). C-reactive protein presented moderate positive correlation with leukocytes (r = 0.5479; p = 0.01), and moderate negative correlation with albumin (r = - 0.5974; p = 0.006) and red blood cells (r = - 0.5878, p = 0.01). A high correlation coefficient was observed in the tests’ evaluation (CI = 0.59–0.78; r = 0.70; P<0.0001). In conclusion, both assays used in this study to measure C-reactive protein have provided safe and reliable quantification of the results. Additionally, despite IHG dogs presented an active inflammatory profile, intermittent hemodialysis has proven to be beneficial, leading to a clinical improvement in life quality of patients, and thus being recommended for stage IV CKD dogs when performed by trained professionals.
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Norton, Katelyn N., Mark B. Badrov, Carly C. Barron, Neville Suskin, Armin Heinecke, and J. Kevin Shoemaker. "Coronary artery disease affects cortical circuitry associated with brain-heart integration during volitional exercise." Journal of Neurophysiology 114, no. 2 (August 2015): 835–45. http://dx.doi.org/10.1152/jn.00008.2015.
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This study tested the hypothesis that coronary artery disease (CAD) alters the cortical circuitry associated with exercise. Observations of changes in heart rate (HR) and in cortical blood oxygenation level-dependent (BOLD) images were made in 23 control subjects [control; 8 women; 63 ± 11 yr; mean arterial pressure (MAP): 90 ± 9 mmHg] (mean ± SD) and 17 similarly aged CAD patients (4 women; 59 ± 9 yr; MAP: 87 ± 10 mmHg). Four repeated bouts each of 30%, 40%, and 50% of maximal voluntary contraction (MVC) force (LAB session), and seven repeated bouts of isometric handgrip (IHG) at 40% MVC force (fMRI session), were performed, with each contraction lasting 20 s and separated by 40 s of rest. There was a main effect of group ( P = 0.03) on HR responses across all IHG intensities. Compared with control, CAD demonstrated less task-dependent deactivation in the posterior cingulate cortex and medial prefrontal cortex, and reduced activation in the right anterior insula, bilateral precentral cortex, and occipital lobe ( P < 0.05). When correlated with HR, CAD demonstrated reduced activation in the bilateral insula and posterior cingulate cortex, and reduced deactivation in the dorsal anterior cingulate cortex, and bilateral precentral cortex ( P < 0.05). The increased variability in expected autonomic regions and decrease in total cortical activation in response to the IHG task are associated with a diminished HR response to volitional effort in CAD. Therefore, relative to similarly aged and healthy individuals, CAD impairs the heart rate response and modifies the cortical patterns associated with cardiovascular control during IHG.
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Hickey, F. B., J. B. Corcoran, B. Griffin, U. Bhreathnach, H. Mortiboys, H. M. Reid, D. Andrews, et al. "IHG-1 Increases Mitochondrial Fusion and Bioenergetic Function." Diabetes 63, no. 12 (July 9, 2014): 4314–25. http://dx.doi.org/10.2337/db13-1256.
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Caldas, J. R., R. B. Panerai, A. M. Salinet, E. Seng-Shu, G. S. R. Ferreira, L. Camara, R. H. Passos, et al. "Dynamic cerebral autoregulation is impaired during submaximal isometric handgrip in patients with heart failure." American Journal of Physiology-Heart and Circulatory Physiology 315, no. 2 (August 1, 2018): H254—H261. http://dx.doi.org/10.1152/ajpheart.00727.2017.
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The incidence of neurological complications, including stroke and cognitive dysfunction, is elevated in patients with heart failure (HF) with reduced ejection fraction. We hypothesized that the cerebrovascular response to isometric handgrip (iHG) is altered in patients with HF. Adults with HF and healthy volunteers were included. Cerebral blood velocity (CBV; transcranial Doppler, middle cerebral artery) and arterial blood pressure (BP; Finometer) were continuously recorded supine for 6 min, corresponding to 1 min of baseline and 3 min of iHG exercise, at 30% maximum voluntary contraction, followed by 2 min of recovery. The resistance-area product was calculated from the instantaneous BP-CBV relationship. Dynamic cerebral autoregulation (dCA) was assessed with the time-varying autoregulation index estimated from the CBV step response derived by an autoregressive moving-average time-domain model. Forty patients with HF and 23 BP-matched healthy volunteers were studied. Median left ventricular ejection fraction was 38.5% (interquartile range: 0.075%) in the HF group. Compared with control subjects, patients with HF exhibited lower time-varying autoregulation index during iHG, indicating impaired dCA ( P < 0.025). During iHG, there were steep rises in CBV, BP, and heart rate in control subjects but with different temporal patterns in HF, which, together with the temporal evolution of resistance-area product, confirmed the disturbance in dCA in HF. Patients with HF were more likely to have impaired dCA during iHG compared with age-matched control subjects. Our results also suggest an impairment of myogenic, neurogenic, and metabolic control mechanisms in HF. The relationship between impaired dCA and neurological complications in patients with HF during exercise deserves further investigation. NEW & NOTEWORTHY Our findings provide the first direct evidence that cerebral blood flow regulatory mechanisms can be affected in patients with heart failure during isometric handgrip exercise. As a consequence, eventual blood pressure modulations are buffered less efficiently and metabolic demands may not be met during common daily activities. These deficits in cerebral autoregulation are compounded by limitations of the systemic response to isometric exercise, suggesting that patients with heart failure may be at greater risk for cerebral events during exercise.
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Li, Yunyun, Jiating Zhao, Yu-Feng Li, Xiaohan Xu, Bowen Zhang, Yongjie Liu, Liwei Cui, Bai Li, Yuxi Gao, and Zhifang Chai. "Comparative metalloproteomic approaches for the investigation proteins involved in the toxicity of inorganic and organic forms of mercury in rice (Oryza sativa L.) roots." Metallomics 8, no. 7 (2016): 663–71. http://dx.doi.org/10.1039/c5mt00264h.
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Bittencourt, Leonardo Oliveira, Victória Santos Chemelo, Walessa Alana Bragança Aragão, Bruna Puty, Aline Dionizio, Francisco Bruno Teixeira, Mileni Silva Fernandes, et al. "From Molecules to Behavior in Long-Term Inorganic Mercury Intoxication: Unraveling Proteomic Features in Cerebellar Neurodegeneration of Rats." International Journal of Molecular Sciences 23, no. 1 (December 22, 2021): 111. http://dx.doi.org/10.3390/ijms23010111.
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Mercury is a severe environmental pollutant with neurotoxic effects, especially when exposed for long periods. Although there are several evidences regarding mercury toxicity, little is known about inorganic mercury (IHg) species and cerebellum, one of the main targets of mercury associated with the neurological symptomatology of mercurial poisoning. Besides that, the global proteomic profile assessment is a valuable tool to screen possible biomarkers and elucidate molecular targets of mercury neurotoxicity; however, the literature is still scarce. Thus, this study aimed to investigate the effects of long-term exposure to IHg in adult rats’ cerebellum and explore the modulation of the cerebellar proteome associated with biochemical and functional outcomes, providing evidence, in a translational perspective, of new mercury toxicity targets and possible biomarkers. Fifty-four adult rats were exposed to 0.375 mg/kg of HgCl2 or distilled water for 45 days using intragastric gavage. Then, the motor functions were evaluated by rotarod and inclined plane. The cerebellum was collected to quantify mercury levels, to assess the antioxidant activity against peroxyl radicals (ACAPs), the lipid peroxidation (LPO), the proteomic profile, the cell death nature by cytotoxicity and apoptosis, and the Purkinje cells density. The IHg exposure increased mercury levels in the cerebellum, reducing ACAP and increasing LPO. The proteomic approach revealed a total 419 proteins with different statuses of regulation, associated with different biological processes, such as synaptic signaling, energy metabolism and nervous system development, e.g., all these molecular changes are associated with increased cytotoxicity and apoptosis, with a neurodegenerative pattern on Purkinje cells layer and poor motor coordination and balance. In conclusion, all these findings feature a neurodegenerative process triggered by IHg in the cerebellum that culminated into motor functions deficits, which are associated with several molecular features and may be related to the clinical outcomes of people exposed to the toxicant.
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Busch, Stephen A., Lydia L. Simpson, Frances Sobierajski, Laurel Riske, Philip N. Ainslie, Chris K. Willie, Mike Stembridge, Jonathan P. Moore, and Craig D. Steinback. "Muscle sympathetic reactivity to apneic and exercise stress in high-altitude Sherpa." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 318, no. 3 (March 1, 2020): R493—R502. http://dx.doi.org/10.1152/ajpregu.00119.2019.
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Lowland-dwelling populations exhibit persistent sympathetic hyperactivity at altitude that alters vascular function. High-altitude populations, such as Sherpa, have previously exhibited greater peripheral blood flow in response to acute stress than Lowlanders, which may be explained through lower sympathetic activity. Our purpose was to determine whether Sherpa exhibit lower sympathetic reactivity to stress than Lowlanders. Muscle sympathetic nerve activity (MSNA; microneurography) was measured at rest in Lowlanders ( n = 14; age = 27 ± 6 yr) at 344 m and between 1 and 10 days at 5,050 m. Sherpa (age = 32 ± 11 yr) were tested at 5,050 m ( n = 8). Neurovascular reactivity (i.e., change in MSNA patterns) was measured during maximal end-expiratory apnea, isometric hand grip (IHG; 30% maximal voluntary contraction for 2-min), and postexercise circulatory occlusion (PECO; 3 min). Burst frequency (bursts/min) and incidence (bursts/100 heartbeats) and total normalized SNA (arbitrary units/min) were analyzed at rest, immediately before apnea breakpoint, and during the last minute of IHG and PECO. Vascular responses to apnea, IHG, and PECO were also measured. MSNA reactivity to apnea was smaller in Sherpa than Lowlanders at 5,050 m, although blood pressure responses were similar between groups. MSNA increases in Lowlanders during apnea at 5,050 m were significantly lower than at 344 m ( P < 0.05), indicating that a possible sympathetic ceiling was reached in Lowlanders at 5,050 m. MSNA increased similarly during IHG and PECO in Lowlanders at both 334 m and 5,050 m and in Sherpa at 5,050 m, while vascular changes (mean brachial arterial pressure, contralateral brachial flow and resistance) were similar between groups. Sherpa demonstrate overall lower sympathetic reactivity that may be a result of heightened vascular responsiveness to potential apneic stress at altitude.
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Ning Lau, Sarah Sau, Dennis Tak Loi Ku, and Pak Yin Anthony Liu. "HGG-04. INFANTILE HIGH GRADE GLIOMA: HONG KONG EXPERIENCE." Neuro-Oncology 25, Supplement_1 (June 1, 2023): i39. http://dx.doi.org/10.1093/neuonc/noad073.153.
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Abstract OBJECTIVE To review local infantile high-grade glioma (IHG) patients and their outcome. BACKGROUND Infantile high-grade glioma is diagnosed in patients less than 12 months of age. Studies have shown that it displays a more stable genome, and are usually single mutation driven. The most identifiable mutations are receptor tyrosine kinase (RTK) fusion, such as NTRK family, ROS1, ALK and MET. The current principal treatment remains to be surgery, but it is challenging for a complete resection due to hemispheric involvement. Chemotherapeutic drugs for IHG are still under debate, with targeted therapy showing efficacy in promoting tumour shrinkage. Despite being a challenging CNS tumour, the overall survival of IHG is superior to other paediatric high-grade gliomas. Result: We identified 7 IHG patients in our local data. Mean age of diagnosis was 3 months. There were 4 males and 3 females. Six patients had histological diagnosis of glioblastoma and 1 patient had diagnosis of anaplastic astrocytoma. One patient had her tumour located in infratentorial region. Three patients had multilobar involvement. NTRK fusion was found in 4 patients (NTRK fusion, ETV6-NTRK3 fusion and TPR-NTRK1 fusion). ALK fusion was found in 1 patient (HMBOX1-ALK). All patients underwent chemotherapy, with four patients switched to NTRK inhibitor afterwards. Surgery was performed at various time points for these patients. One patient passed away at 22 months of age at submission of this abstract. CONCLUSION A local review gives us more insight into the updated diagnosis, management and outcome of infantile patients diagnosed with high-grade glioma. Infantile high-grade glioma should be regarded as a unique tumour entity and a multidisciplinary approach is paramount in improving survival for this group of patients.
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Ku, Dennis T. L., Anthony P. Y. Liu, Amanda N. C. Kan, Liz Y. P. Yuen, M. K. Shing, Carol Y. L. Yan, Eric Fu, et al. "HGG-37. A case ofETV6-NTRK3 fusion driven infantile hemispheric glioma (IHG) with acquired drug resistance against first- and second-generation NTRK-inhibitors." Neuro-Oncology 24, Supplement_1 (June 1, 2022): i69. http://dx.doi.org/10.1093/neuonc/noac079.252.
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Abstract A 3-month-old girl had left cerebral infantile hemispheric glioma (IHG), H3 wild type (wt), Grade IV (WHO2020) with diffuse leptomeningeal and spinal metastasis. Craniotomies were performed twice which achieved partial resection. Histopathology revealed high grade glioma, Ki67 30-40%, mitosis and widespread necrosis. IHC showed H3wt, IDH-, and retained INI-1. RNAseq found ETV6-NTRK3 fusion. She was treated per Baby POG-9233, however after 3 cycles, there was mixed response (static for primary, partial response for metastasis). She had severe developmental delay, right hemiparesis and dysphagia. Aiming for better disease control and potential resectability, we switched to first-generation NTRK-inhibitor, Larotrectinib. MRI at 3 months showed significant interval reduction in tumour size, then became static at 6 months. She was stable with gradual neurological improvement until 10 months after Larotrectinib, there was worsening neurology and imaging confirmed tumour progression with haemorrhage. Craniotomy was performed for haemostasis and tumour debulking. Histopathology showed same IHG with ETV6-NTRK3 fusion. Targeted panel sequencing found NTRK3 p.Gly623Arg mutation, a solvent-front substitution responsible for acquired resistance to first-generation TRK-inhibitors. BRAFV600E and MET amplification were not detected. Larotrectinib was switched to second-generation NTRK-inhibitor, Selitrectinib. MRI at 1 month showed post-operative changes, but disease progressed at 3 months and in an accelerated manner over the course of 10 days while on therapy. Choice of conventional chemotherapy and radiotherapy were discussed, but the girl deteriorated rapidly and deceased (3 months from start of Selitrectinib, 19 months from diagnosis). CONCLUSION: IHG is aggressive with challenging surgery and medical treatment. The use of small molecular inhibitor requires careful consideration, i.e. treatment effect, toxicity and potential acquired drug resistance as showed in this case. For unresectable tumour, it may be inevitable as we also reported a similar case with ROS1 fusion. Access to newer novel agents is difficult while therapeutic effect is uncertain.
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Richardson, Roberto, Manuel Tapia, and Flavia Landeros. "Cartografía de riesgo de inundación, por modelo de IHG." Revista Geográfica de Chile Terra Australis 55, no. 1 (December 27, 2019): 66–73. http://dx.doi.org/10.23854/07199562.2019551.richardson66.
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Hickey, Fionnuala B., James B. Corcoran, Neil G. Docherty, Brenda Griffin, Una Bhreathnach, Fiona Furlong, Finian Martin, Catherine Godson, and Madeline Murphy. "IHG-1 Promotes Mitochondrial Biogenesis by Stabilizing PGC-1α." Journal of the American Society of Nephrology 22, no. 8 (July 22, 2011): 1475–85. http://dx.doi.org/10.1681/asn.2010111154.
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Iwai-Shimada, Miyuki, Yayoi Kobayashi, Tomohiko Isobe, Shoji F. Nakayama, Makiko Sekiyama, Yu Taniguchi, Shin Yamazaki, et al. "Comparison of Simultaneous Quantitative Analysis of Methylmercury and Inorganic Mercury in Cord Blood Using LC-ICP-MS and LC-CVAFS: The Pilot Study of the Japan Environment and Children’s Study." Toxics 9, no. 4 (April 9, 2021): 82. http://dx.doi.org/10.3390/toxics9040082.
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Prenatal exposure to methylmercury (MeHg) affects child development after birth. However, many epidemiological studies have evaluated total mercury levels without analyzing speciation. Biomonitoring of MeHg and inorganic mercury (IHg) is essential to reveal each exposure level. In this study, we compared a high-throughput analysis for mercury speciation in blood using liquid chromatography-inductively coupled plasma-mass spectrometry (LC-ICP-MS) and liquid chromatography-cold vapor atomic fluorescence spectrometry (LC-CVAFS). The validated LC-ICP-MS method was applied to 101 maternal blood and 366 cord blood samples in the pilot study of the Japan Environment and Children’s Study (JECS). The accuracy of the LC-CVAFS method ranged 90–115% determined by reference material analysis. To evaluate the reliability of 366 cord blood samples, fifty cord blood samples were randomly selected and analyzed using LC-CVAFS. The median (5th–95th percentile) concentrations of MeHg and IHg were 5.4 (1.9–15) and 0.33 (0.12–0.86) ng/mL, respectively, in maternal blood, and 6.3 (2.5–15) and 0.21 (0.08–0.49) ng/mL, respectively, in cord blood. Inter-laboratory comparison showed a relatively good agreement between LC-ICP-MS and LC-CVAFS. The median cord blood:maternal blood ratios of MeHg and IHg were 1.3 and 0.5, respectively. By analyzing speciation, we could focus on the health effects of each chemical form.
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Souza, Luiz Humberto Rodrigues, Hugo de Luca Corrêa, Thiago dos Santos Rosa, Rodrigo Vanerson Passos Neves, Lysleine Alves Deus, Rafael Reis Olher, Joyce Bomfim Vicente, et al. "Blood pressure decrease in elderly after isometric training: does lactate play a role?" Research, Society and Development 9, no. 9 (September 1, 2020): e655997433. http://dx.doi.org/10.33448/rsd-v9i9.7433.
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This study aimed to investigate the effect of isometric handgrip (IHG) training on the blood pressure (BP) reduction in prehypertensive and hypertensive elderly people, and the possible role of lactate and redox balance. Thirty-three older (75.3±1.3 years old) were allocated to a non-exercise control (CG, n=11), prehypertensive (PHG, n=10), and hypertensive (HG, n=12) groups. PHG and HG performed a total of 8 sets of 1-min bilateral contractions at 30% maximal voluntary isometric contraction, each separated by 1-minute rest-pause. IHG training was performed for 8-week, 3 times a week on non-consecutive days. Systolic BP (SBP) and heart rate (HR) decreased post-training on PHG (-10 mm Hg; -5 bpm) and HG (-16 mm Hg; -9 bpm), respectively. Diastolic BP (DBP) decreased for HG only (-9 mm Hg) (P < 0.05). In addition, the decrease in BP occurred in parallel to a better redox balance and increased bioavailability of nitric oxide in PHG and HG (P < 0.05). Also, the variables that most present association to SBP decrease were capillary blood lactate concentration and muscle strength (P < 0.05). In summary, IHG training may be practical in improving clinical status of prehypertensive and hypertensive patients, by improving BP control, NO- bioavailability and redox balance. Further studies are required to elucidate the pathways of lactate concentration in blood-flow during exercise.