Journal articles on the topic 'PTXs'
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Pazour, G. J., O. A. Sineshchekov, and G. B. Witman. "Mutational analysis of the phototransduction pathway of Chlamydomonas reinhardtii." Journal of Cell Biology 131, no. 2 (October 15, 1995): 427–40. http://dx.doi.org/10.1083/jcb.131.2.427.
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Chlamydomonas has two photobehavioral responses, phototaxis and photoshock. Rhodopsin is the photoreceptor for these responses and the signal transduction process involves transmembrane Ca2+ fluxes. This causes transient changes in flagellar beating, ultimately resulting in phototaxis or photoshock. To identify components that make up this signal transduction pathway, we generated nonphototactic strains by insertional mutagenesis. Seven new phototaxis genes were identified (ptx2-ptx8); alleles of six of these are tagged by the transforming DNA and therefore should be easily cloned. To order the mutants in the pathway, we characterized them electrophysiologically, behaviorally, and structurally, ptx5, ptx6, and ptx7 have normal light-induced photoreceptor currents (PRC) and flagellar currents (FC) but their pattern of swimming does not change in the normal manner when the intraflagellar Ca2+ concentration is decreased, suggesting that they have defects in the ability of their axonemes to respond to changes in Ca2+ concentration. ptx2 and ptx8 lack the FC but have normal PRCs, suggesting that they are defective in the flagellar Ca2+ channel or some factor that regulates it. ptx4 mutants have multiple eye-spots. ptx3 mutants are defective in a component essential for phototaxis but bypassed during photoshock; this component appears to be located downstream of the PRC but upstream of the axoneme.
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Kathariya, Rahul, Hansa Jain, Dnyneshwari Gujar, Archana Singh, Himanshu Ajwani, and Devendra Mandhyan. "Pentraxins as Key Disease Markers for Periodontal Diagnosis." Disease Markers 34, no. 3 (2013): 143–51. http://dx.doi.org/10.1155/2013/259273.
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Periodontal diseases are characterized by a complex set of biologic interactions between a diverse and dynamic microbial ecosystem and the host’s multifaceted and responsive immune and inflammatory machinery. Such interactions between microbial pathogens and various host response systems play a critical role in the development and progression of periodontal disease via the release of inflammatory and immune mediators. Advances in periodontal disease diagnostic are moving toward methods whereby periodontal risk can be identified and quantified by detecting such inflammatory mediators in its sequential pathophysiology. Pentraxins (PTXs) are classical mediators of inflammation and markers of acute-phase reaction. They are a super family of multifunctional molecules characterized by multimeric structure, divided into “short” PTXs and “long” PTXs. C-reactive protein (CRP) and pentraxin-3 (PTX3) are prototypic molecules of the short and long PTX family, respectively. Evidence suggests that PTXs acts as a non-redundant component of the humoral arm of innate immunity, downstream of, and complementary to, cellular recognition, as well as a tuner of inflammation. CRP is a cheaper biomarker and more readily available in everyday clinical practice compared with other inflammatory markers, on the other hand, PTX3 is believed to be the true independent indicator of disease activity and could have clinical implication in diagnosing the “at site” inflammatory status of the periodontal disease. These pentraxins are sensitive and specific in the diagnosis and prognosis of chronic diseases. Thus the pentraxins could be used as preferred biomarkers in periodontal disease diagnosis.
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Colmer, Jane A., and Abdul N. Hamood. "Molecular analysis of thePseudomonas aeruginosaregulatory genesptxRandptxS." Canadian Journal of Microbiology 47, no. 9 (September 1, 2001): 820–28. http://dx.doi.org/10.1139/w01-088.
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We have previously described two Pseudomonas aeruginosa genes, ptxR, which enhances toxA and pvc ( the pyoverdine chromophore operon) expression, and ptxS, the first gene of the kgu operon for the utilization of 2-ketogluconate by P. aeruginosa. ptxS interferes with the effect of ptxR on toxA expression. In this study, we have utilized DNA hybridization experiments to determine the presence of ptxR and ptxS homologous sequences in several gram-negative bacteria. ptxR homologous sequences were detected in P. aeruginosa strains only, while ptxS homologous sequences were detected in P. aeruginosa, Pseudomonas putida, and Pseudomonas fluorescens. Using Northern blot hybridization experiments and a ptxSlacZ fusion plasmid, we have shown that P. aeruginosa ptxR and ptxS are expressed in P. putida and P. fluorescens. Additional Northern blot hybridization experiments confirmed that ptxS is transcribed in P. putida and P. fluorescens strains that carried no plasmid. The presence of a PtxS homologue in these strains was examined by DNA-gel shift experiments. Specific gel shift bands were detected when the lysates of P. aeruginosa, P. putida, and P. fluorescens were incubated with the ptxS operator site as probe. kgu-hybridizing sequences were detected in P. putida and P. fluorescens. These results suggest that (i) ptxR is present in P. aeruginosa, while ptxS is present in P. aeruginosa, P. putida, and P. fluorescens; (ii) both ptxR and ptxS are expressed in P. putida and P. fluorescens; and (iii) a PtxS homologue may exist in P. putida and P. fluorescens.Key words: Pseudomonas aeruginosa, ptxR, ptxS, DNA hybridization, kgu operon.
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Swanson, Britta L., and Abdul N. Hamood. "Autoregulation of the Pseudomonas aeruginosa Protein PtxS Occurs through a Specific Operator Site within the ptxS Upstream Region." Journal of Bacteriology 182, no. 15 (August 1, 2000): 4366–71. http://dx.doi.org/10.1128/jb.182.15.4366-4371.2000.
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ABSTRACT We have previously shown that the Pseudomonas aeruginosa toxA regulatory protein PtxS autoregulates its own synthesis by binding to a 52-bp fragment. The 3′ end of the 52-bp fragment is located 58 bp 5′ of the ptxS translation start site. We have identified a 14-bp palindromic sequence (TGAAACCGGTTTCA) within the 52-bp fragment. In this study, we used site-directed mutagenesis and promoter fusion experiments to determine if PtxS binds specifically to this palindromic sequence and regulatesptxS expression. We have also tried to determine the roles of specific nucleotides within the palindromic sequence in PtxS binding and ptxS expression. Initial promoter fusion experiments confirmed that the 52-bp fragment does not overlap with the region that carries the ptxS promoter activity. PtxS binding was eliminated upon the deletion of the 14-bp palindromic sequence from the 52-bp fragment. In addition, the deletion of the 14-bp sequence caused a significant enhancement in ptxS expression in theP. aeruginosa strain PAO1 and the ptxS isogenic mutant PAO::ptxS. Mutation of specific nucleotides within the 14-bp sequence eliminated, reduced, or had no effect on PtxS binding. However, mutations of several of these nucleotides produced a significant increase in ptxSexpression in both PAO1 and PAO::ptxS. These results suggest that (i) the 14-bp palindromic sequence and specific nucleotides within it play a role in PtxS binding and (ii) deletion of the palindromic sequence or changing of certain nucleotides within it interferes with another mechanism that may regulate ptxSexpression.
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Swanson, Britta L., Jane A. Colmer, and Abdul N. Hamood. "The Pseudomonas aeruginosa Exotoxin A Regulatory Gene, ptxS: Evidence for Negative Autoregulation." Journal of Bacteriology 181, no. 16 (August 15, 1999): 4890–95. http://dx.doi.org/10.1128/jb.181.16.4890-4895.1999.
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ABSTRACT We have previously described a Pseudomonas aeruginosagene, ptxR, which enhances exotoxin A production at the transcriptional level. We have also described another gene,ptxS, which is transcribed divergently fromptxR and interferes with the enhancement of exotoxin A synthesis by ptxR. However, the mechanisms through whichptxR and/or ptxS are regulated is not known. In this study, we attempted (by using the DNA gel shift assay) to determine if P. aeruginosa contains a potential regulatory protein that binds specifically to the ptxR orptxS upstream region. In the initial analysis, different-sized gel shift bands were detected when a probe containing the ptxR-ptxS intergenic region was incubated with the lysate of P. aeruginosa PAO1. The strongest binding activity was detected with a smaller fragment that represents theptxS upstream region. Additional deletion analysis localized the binding to a 52-bp fragment immediately upstream ofptxS. The gel shift band was not detected when the 52-bp fragment was incubated with the lysate of the ptxS isogenic mutant PAO1::ptxS. However, the binding band was regenerated when a plasmid carrying ptxS intact was introduced into PAO1::ptxS. In addition, the gel shift band was detected when the 52-bp fragment was incubated with a lysate of Escherichia coli in which ptxS was overexpressed from the T7 promoter. The effect of PtxS onptxS expression was examined by using aptxS-lacZ fusion plasmid. The level of β-galactosidase activity produced by PAO1::ptxS carrying the fusion plasmid was four- to fivefold higher than that produced by PAO1 carrying the same plasmid. Using DNase I footprinting analysis, the binding region was specified to a 20-bp fragment. Within the fragment, a 14-bp palindromic sequence exists that may function as a PtxS binding site. These results suggest that PtxS autoregulates its synthesis by binding to a specific sequence within the ptxSupstream region.
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Westfall, Landon W., A. Marie Luna, Michael San Francisco, Stephen P. Diggle, Kathryn E. Worrall, Paul Williams, Miguel Cámara, and Abdul N. Hamood. "The Pseudomonas aeruginosa global regulator MvaT specifically binds to the ptxS upstream region and enhances ptxS expression." Microbiology 150, no. 11 (November 1, 2004): 3797–806. http://dx.doi.org/10.1099/mic.0.27270-0.
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Exotoxin A production in Pseudomonas aeruginosa is regulated positively or negatively by several genes. Two such regulatory genes, ptxR and ptxS, which are divergently transcribed from each other, have been described previously. While computer analysis suggested that the ptxR-ptxS intergenic region contains potential binding sites for several regulatory proteins, the mechanism that regulates the expression of either ptxR or ptxS in P. aeruginosa is not known. The presence of a P. aeruginosa protein complex that specifically binds to a segment within this region was determined. In this study the binding region was localized to a 150 bp fragment of the intergenic region and the proteins that constitute the binding complex were characterized as P. aeruginosa HU and MvaT. Recombinant MvaT was purified as a fusion protein (MAL-MvaT) and shown to specifically bind to the ptxR-ptxS intergenic region. A PAO1 isogenic mutant defective in mvaT, PAOΔmvaT, was constructed and characterized. The lysate of PAOΔmvaT failed to bind to the 150 bp probe. The effect of mvaT on ptxS and ptxR expression was examined using real-time PCR experiments. The expression of ptxS was lower in PAOΔmvaT than in PAO1, but no difference was detected in ptxR expression. These results suggest that MvaT positively regulates ptxS expression by binding specifically to the ptxS upstream region.
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Alcántara-Rubira, Alex, Víctor Bárcena-Martínez, Maribel Reyes-Paulino, Katherine Medina-Acaro, Lilibeth Valiente-Terrones, Angélica Rodríguez-Velásquez, Rolando Estrada-Jiménez, and Omar Flores-Salmón. "First Report of Okadaic Acid and Pectenotoxins in Individual Cells of Dinophysis and in Scallops Argopecten purpuratus from Perú." Toxins 10, no. 12 (November 23, 2018): 490. http://dx.doi.org/10.3390/toxins10120490.
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Causative species of Harmful Algal Bloom (HAB) and toxins in commercially exploited molluscan shellfish species are monitored weekly from four classified shellfish production areas in Perú (three in the north and one in the south). Okadaic acid (OA) and pectenotoxins (PTXs) were detected in hand-picked cells of Dinophysis (D. acuminata-complex and D. caudata) and in scallops (Argopecten purpuratus), the most important commercial bivalve species in Perú. LC-MS analyses revealed two different toxin profiles associated with species of the D. acuminata-complex: (a) one with OA (0.3–8.0 pg cell−1) and PTX2 (1.5–11.1 pg cell−1) and (b) another with only PTX2 which included populations with different toxin cell quota (9.3–9.6 pg cell−1 and 5.8–9.2 pg cell−1). Toxin results suggest the likely presence of two morphotypes of the D. acuminata-complex in the north, and only one of them in the south. Likewise, shellfish toxin analyses revealed the presence of PTX2 in all samples (10.3–34.8 µg kg−1), but OA (7.7–15.2 µg kg−1) only in the northern samples. Toxin levels were below the regulatory limits established for diarrhetic shellfish poisoning (DSP) and PTXs (160 µg OA kg−1) in Perú, in all samples analyzed. This is the first report confirming the presence of OA and PTX in Dinophysis cells and in shellfish from Peruvian coastal waters.
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Cropano, Catrina, Tomaz Mesar, David Turay, David King, Daniel Yeh, Peter Fagenholz, George Velmahos, and Marc A. de Moya. "Pneumothoraces on Computed Tomography Scan: Observation using the 35 Millimeter Rule is Safe." Panamerican Journal of Trauma, Critical Care & Emergency Surgery 4, no. 2 (2015): 48–53. http://dx.doi.org/10.5005/jp-journals-10030-1116.
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ABSTRACT Introduction The management of a pneumothorax (PTX) either by observation or with a tube thoracostomy (TT) has long been dictated by practitioner discretion rather than objective criteria. Many physicians elect to routinely place a TT for traumatic PTX, particularly when patients undergo positive pressure ventilation (PPV). Placement of unnecessary TT exposes patients to avoidable morbidity and may prolong hospitalization. Based on prior work establishing a cutoff, we hypothesized that all PTXs ≤35 mm in patients who have no physiologic derangement may be safely observed without TT regardless of the need for PPV. Materials and methods Retrospective review of all patients diagnosed with a PTX between 1/2009 and 2/2013. All PTXs visible on chest computed tomography (CT) were identified. Any patient with an associated significant hemothorax or those patients who were moribund were excluded. All PTXs were measured by measuring the perpendicular distance of the largest air pocket between the chest wall and the mediastinal or pulmonary structure. Management of the PTX was categorized as observation or TT. Observed PTXs were labeled as success or failure with failure defined as enlargement of the PTX or physiologic deterioration, requiring a TT. Results Out of 165 PTXs, 17 (10.3%) measured >35 mm, whereas 148 (89.7%) measured ≤35 mm. Of the 17 > 35 mm, 15 (88.2%) received immediate TT. Of the two PTXs >35 mm which were observed, one received a delayed TT for a pleural effusion (6 days after PTX diagnosis) and one (5.9 %) was safely observed. Of the 148 PTXs which measured ≤35 mm, 10 (6.8%) received immediate TT. Of the 138 remaining PTXs, 129 (93.5%) were safely managed without TT. Six (4.3%) of the PTXs initially observed eventually required TT placement for enlargement of the PTX. Only one of those six had manifested ongoing desaturations prior to TT. The remaining three cases received TT for reasons unrelated to the PTX. Of the 27 PPV cases in the ≤35 mm cohort, none contributed to the six failures. A cutoff measurement of 35 mm demonstrated a negative predictive value (NPV) of 95.7% in its ability to predict successful observation of the PTX with an area under the receiver operating characteristic (ROC) curve of 0.90. Conclusion All PTXs measuring ≤35 mm perpendicular to the chest wall without physiologic derangement may be safely observed independent of the need for mechanical ventilation. How to cite this article Cropano C, Mesar T, Turay D, King D, Yeh D, Fagenholz P, Velmahos G, de Moya MA. Pneumothoraces on Computed Tomography Scan: Observation using the 35 Millimeter Rule is Safe. Panam J Trauma Crit Care Emerg Surg 2015;4(2):48-53.
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Pineda-Molina, E., A. Daddaoua, T. Krell, J. L. Ramos, J. M. García-Ruiz, and J. A. Gavira. "In situX-ray data collection from highly sensitive crystals ofPseudomonas putidaPtxS in complex with DNA." Acta Crystallographica Section F Structural Biology and Crystallization Communications 68, no. 11 (October 30, 2012): 1307–10. http://dx.doi.org/10.1107/s1744309112028540.
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Pseudomonas putidaPtxS is a member of the LacI protein family of transcriptional regulators involved in glucose metabolism. All genes involved in this pathway are clustered into two operons,kguandgad. PtxS controls the expression of thekguandgadoperons as well as its own transcription. The PtxS operator is a perfect palindrome, 5′-TGAAACCGGTTTCA-3′, which is present in all three promoters. Crystallization of native PtxS failed, and PtxS–DNA crystals were finally produced by the counter-diffusion technique. A portion of the capillary used for crystal growth was attached to the end of a SPINE standard cap and directly flash-cooled in liquid nitrogen for diffraction tests. A full data set was collected with a beam size of 10 × 10 µm. The crystal belonged to the trigonal space groupP3, with unit-cell parametersa=b= 213.71,c = 71.57 Å. Only unhandled crystals grown in capillaries of 0.1 mm inner diameter diffracted X-rays to 1.92 Å resolution.
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Daddaoua, Abdelali, Tino Krell, Carlos Alfonso, Bertrand Morel, and Juan-Luis Ramos. "Compartmentalized Glucose Metabolism in Pseudomonas putida Is Controlled by the PtxS Repressor." Journal of Bacteriology 192, no. 17 (June 25, 2010): 4357–66. http://dx.doi.org/10.1128/jb.00520-10.
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ABSTRACT Metabolic flux analysis revealed that in Pseudomonas putida KT2440 about 50% of glucose taken up by the cells is channeled through the 2-ketogluconate peripheral pathway. This pathway is characterized by being compartmentalized in the cells. In fact, initial metabolism of glucose to 2-ketogluconate takes place in the periplasm through a set of reactions catalyzed by glucose dehydrogenase and gluconate dehydrogenase to yield 2-ketogluconate. This metabolite is subsequently transported to the cytoplasm, where two reactions are carried out, giving rise to 6-phosphogluconate, which enters the Entner-Doudoroff pathway. The genes for the periplasmic and cytoplasmic set of reactions are clustered in the host chromosome and grouped within two independent operons that are under the control of the PtxS regulator, which also modulates its own synthesis. Here, we show that although the two catabolic operons are induced in vivo by glucose, ketogluconate, and 2-ketogluconate, in vitro we found that only 2-ketogluconate binds to the regulator with an apparent KD (equilibrium dissociation constant) of 15 μM, as determined using isothermal titration calorimetry assays. PtxS is made of two domains, a helix-turn-helix DNA-binding domain located at the N terminus and a C-terminal domain that binds the effector. Differential scanning calorimetry assays revealed that PtxS unfolds via two events characterized by melting points of 48.1°C and 57.6°C and that, in the presence of 2-ketogluconate, the unfolding of the effector binding domain occurs at a higher temperature, providing further evidence for 2-ketogluconate-PtxS interactions. Purified PtxS is a dimer that binds to the target promoters with affinities in the range of 1 to 3 μM. Footprint analysis revealed that PtxS binds to an almost perfect palindrome that is present within the three promoters and whose consensus sequence is 5′-TGAAACCGGTTTCA-3′. This palindrome overlaps with the RNA polymerase binding site.
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Colmer-Hamood, Jane A., Hironori Aramaki, Jennifer M. Gaines, and Abdul N. Hamood. "Transcriptional analysis of thePseudomonas aeruginosa toxAregulatory geneptxR." Canadian Journal of Microbiology 52, no. 4 (April 1, 2006): 343–56. http://dx.doi.org/10.1139/w05-138.
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The expression of the exotoxin A gene (toxA) in Pseudomonas aeruginosa is a complicated process that involves several regulators, including ptxR, which enhances toxA expression by 4- to 5-fold. Available evidence suggests that ptxR is expressed from two separate promoters, P1 and P2. Previous evidence indicated the presence, within the ptxR upstream region, of binding sites for several regulatory proteins, including PtxS, which negatively regulates ptxR expression. We utilized nested deletion and in vitro transcription analyses to examine the regulation of ptxR expression. The results from nested deletion analysis suggest that under aerobic conditions in iron-deficient medium, ptxR expression follows a biphasic curve that involves the P1 promoter only. Iron eliminated the second peak of ptxR expression but did not affect expression from the P2 promoter. Under microaerobic conditions, iron represses ptxR expression from subclones that carry P1 alone or P2 alone at both early and late stages of growth. Under anaerobic conditions, ptxR expression increases considerably. In addition, our results suggest that different segments of the ptxR upstream region play specific roles in ptxR expression; their deletion caused variations in the level as well as the pattern of ptxR expression. Our results also indicate that negative regulation of ptxR expression by PtxS does not occur through the PtxS binding site within the ptxR–ptxS intergenic region. In vitro transcription analysis using σ70-reconstituted P. aeruginosa RNA polymerase produced one transcript that closely resembles T1, indicating that P1 is recognized by σ70. RNA polymerase reconstituted with either RpoS or AlgU produced no transcripts. However, a transcript was produced by RpoH-reconstituted RNA polymerase.Key words: ptxR, regulation, Pseudomonas aeruginosa, PAO1.
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Deng, Bi-Ying, Ning Li, Wen-Shen Wu, Xiao-Guang He, Jin-Feng Li, Tian-li Huang, Yu-Chan Li, and Shuang-lan Jiang. "Use of Neonatal Lung Ultrasound for the Early Detection of Pneumothorax." American Journal of Perinatology 37, no. 09 (May 30, 2019): 907–13. http://dx.doi.org/10.1055/s-0039-1688999.
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Objective Pneumothorax (PTX) can be diagnosed using lung ultrasonography (LUS) in adult patients, but there are only a few reports of LUS in PTX diagnosis in neonates. The aim of the study was to assess the diagnostic accuracy for PTX. Study Design This was a retrospective review study performed in our neonatal intensive care unit (level III) between June 2015 and June 2018. All eligible patients underwent an LUS scan before undergoing a chest X-ray (CXR), which was considered the reference standard. When a diagnosis of PTX was inconsistent between LUS and CXR, a chest computed tomography (CT) scan or chest drain was considered the gold standard. Results Among 86 infants included in the study, 30 (34.9%) were diagnosed with PTX. In these 30 infants, 35 PTXs were detected by bedside LUS (five bilateral PTXs). Moreover, 11 infants with 14 PTXs were diagnosed only by LUS and were missed by CXR. Out of these 11 infants, 7 underwent a CT scan, whereas the remaining 4 underwent thoracentesis that confirmed PTX diagnosis. Conclusion In neonates with PTX, LUS was more sensitive and specific for the early detection of PTX compared with CXR.
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Boundy, Michael J., D. Tim Harwood, Andreas Kiermeier, Cath McLeod, Jeane Nicolas, and Sarah Finch. "Risk Assessment of Pectenotoxins in New Zealand Bivalve Molluscan Shellfish, 2009–2019." Toxins 12, no. 12 (December 6, 2020): 776. http://dx.doi.org/10.3390/toxins12120776.
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Pectenotoxins (PTXs) are produced by Dinophysis spp., along with okadaic acid, dinophysistoxin 1, and dinophysistoxin 2. The okadaic acid group toxins cause diarrhetic shellfish poisoning (DSP), so are therefore regulated. New Zealand currently includes pectenotoxins within the DSP regulations. To determine the impact of this decision, shellfish biotoxin data collected between 2009 and 2019 were examined. They showed that 85 samples exceeded the DSP regulatory limit (0.45%) and that excluding pectenotoxins would have reduced this by 10% to 76 samples. The incidence (1.3%) and maximum concentrations of pectenotoxins (0.079 mg/kg) were also found to be low, well below the current European Food Safety Authority (EFSA) safe limit of 0.12 mg/kg. Inclusion within the DSP regulations is scientifically flawed, as pectenotoxins and okadaic acid have a different mechanism of action, meaning that their toxicities are not additive, which is the fundamental principle of grouping toxins. Furthermore, evaluation of the available toxicity data suggests that pectenotoxins have very low oral toxicity, with recent studies showing no oral toxicity in mice dosed with the PTX analogue PTX2 at 5000 µg/kg. No known human illnesses have been reported due to exposure to pectenotoxins in shellfish, a fact which combined with the toxicity data indicates that they pose negligible risk to humans. Regulatory policies should be commensurate with the level of risk, thus deregulation of PTXs ought to be considered, a stance already adopted by some countries.
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Reguera, Beatriz, and Juan Blanco. "Dinophysis Toxins: Distribution, Fate in Shellfish and Impacts." Toxins 11, no. 7 (July 16, 2019): 413. http://dx.doi.org/10.3390/toxins11070413.
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Several planktonic dinoflagellate species of the genus Dinophysis produce one or two groups of lipophilic toxins: (i) okadaic acid (OA) and its derivatives, the dinophysistoxins (DTXs), and (ii) pectenotoxins (PTXs) [...]
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Kim, Gunzung, Imran Ashraf, Jeongsook Eom, and Yongwan Park. "Optimal Path Configuration with Coded Laser Pilots for Charging Electric Vehicles Using High Intensity Laser Power Beams." Applied Sciences 11, no. 9 (April 23, 2021): 3826. http://dx.doi.org/10.3390/app11093826.
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Wireless power transmission (WPT) for wireless charging has been gaining wide attention as a promising approach to miniaturizing the battery size and increasing the maximal total range of an electric vehicle (EV). With an appropriate charging infrastructure, WPT holds great potential to accelerate the acceptance of EVs through users’ higher satisfaction, reducing EV cost, and increasing the driving range and capability. A WPT system based on high-intensity laser power beaming (HILPB) provides an optimal solution for wirelessly charging electric vehicles from a distance of several meters. Despite a large number of WPT approaches, the problem of optimal path configuration for charging EV remains an unexplored area. This paper proposes a method to determine the optimal power transmission path in environments where multiple power transmitters (PTXs) and power receivers (PRXs) are operated simultaneously. To this end, we modeled the HILPB power that reaches a PRX equipped with a photovoltaic (PV) array and validated the model by simulating the WPT process in an environment with multiple PTXs and PRXs using a direct-sequence optical code division multiple access (DS-OCDMA) system. In the simulation environment, upon receiving a request from a PRX, a PTX sent its power channel information through optically encoded laser pulses using each available wireless power channel (WPC). The PRX calculated the maximum deliverable power of a PTX and WPC based on the received channel power indicator of the incident laser beam. Based on the calculation results, it selected the optimal PTX and WPC for its maximum power requirement (MPQ). The MPQ of each PRX was satisfied by applying the algorithm for selecting the PTX according to the alignment and characteristics of the PTXs and PRXs. We modeled a power reception model of the PRX based on a PV array using coded laser pilots and validated it through experimentation. We discussed some algorithms that select the most suitable PTX among several PTXs for which several EVs receive the power it needs.
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Uchida, Hajime, Ryuichi Watanabe, Ryoji Matsushima, Hiroshi Oikawa, Satoshi Nagai, Takashi Kamiyama, Katsuhisa Baba, et al. "Toxin Profiles of Okadaic Acid Analogues and Other Lipophilic Toxins in Dinophysis from Japanese Coastal Waters." Toxins 10, no. 11 (November 6, 2018): 457. http://dx.doi.org/10.3390/toxins10110457.
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The identification and quantification of okadaic acid (OA)/dinophysistoxin (DTX) analogues and pectenotoxins (PTXs) in Dinophysis samples collected from coastal locations around Japan were evaluated by liquid chromatography mass spectrometry. The species identified and analyzed included Dinophysis fortii, D. acuminata, D. mitra (Phalacroma mitra), D. norvegica, D. infundibulus, D. tripos, D. caudata, D. rotundata (Phalacroma rotundatum), and D. rudgei. The dominant toxin found in D. acuminata was PTX2 although some samples contained DTX1 as a minor toxin. D. acuminata specimens isolated from the southwestern regions (Takada and Hiroshima) showed characteristic toxin profiles, with only OA detected in samples collected from Takada. In contrast, both OA and DTX1, in addition to a larger proportion of PTX2, were detected in D. acuminata from Hiroshima. D. fortii showed a toxin profile dominated by PTX2 although this species had higher levels of DTX1 than D. acuminata. OA was detected as a minor toxin in some D. fortii samples collected from Yakumo, Noheji, and Hakata. PTX2 was also the dominant toxin found among other Dinophysis species analyzed, such as D. norvegica, D. tripos, and D. caudata, although some pooled picked cells of these species contained trace levels of OA or DTX1. The results obtained in this study re-confirm that cellular toxin content and profiles are different even among strains of the same species.
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Martin, Marcel, Bertrand Scalabrini, Andre Rioux, and Marie-Anne Xhignesse. "Training Fourth-Year Medical Students in Critical Invasive Skills Improves Subsequent Patient Safety." American Surgeon 69, no. 5 (May 2003): 437–40. http://dx.doi.org/10.1177/000313480306900516.
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Complications after procedures performed by residents are thought to occur most often early in the first postgraduate year (PGY-1). We evaluated the number of pneumothoraces (PTXs) caused by central venous line insertion (CVLI) by two groups of PGY-1 residents in both the first 3 months of residency and the entire year from 1996 through 2000 to determine the impact of CVLI training on PTX. From 1996 through 1998 fourth-year medical students had no specific training in CVLI and learned on the job as residents. Starting with the Class of 1999 we replaced this approach with a structured program in CVLI. Didactic sessions detailing anatomy and technique were followed by skill performance in a fresh cadaver model. Students performed skills initially under the direct supervision of a faculty member, who provided immediate feedback. Videotapes of this performance were reviewed with the students by both surgeons and kinesiologists to correct deficits before repeat sessions. Skills were repeated until competence was attained. Graduating students have made up greater than 90 per cent of our two hospitals’ PGY-1 residents since 1996. Because these residents are responsible for CVLI we are able to obtain performance follow-up in actual clinical settings. We obtained the number of PTXs caused by CVLI for the years 1996 through 2000 as well as for the first 3 months of each academic year (July through September) to determine the impact of our program on this serious complication. The number of PTXs during the first 3 months of 1996–1998 remained stable. After the introduction of our teaching program the number decreased significantly in the years 1999–2000 when compared with 1996–1998 ( P = 0.004, t test). The overall yearly decrease for 1999 versus 1996–1998 approached significance ( P = 0.06). The introduction of a structured teaching program of CVLI skills appears to have a positive impact in reducing morbidity of PTX. The greatest impact occurs within the first 3 months of the new PGY-1 academic year.
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Brimble, Margaret A., and Rosliana Halim. "Synthetic studies toward shellfish toxins containing spiroacetal units." Pure and Applied Chemistry 79, no. 2 (January 1, 2007): 153–62. http://dx.doi.org/10.1351/pac200779020153.
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The synthesis of the ABC spiroacetal-containing fragment of the marine biotoxins, the pectenotoxins (PTXs), is described. The synthetic strategy involves appendage of the highly substituted tetrahydofuran C ring to the AB spiroacetal unit via stereocontrolled cyclization of a γ-hydroxyepoxide. The bis-spiroacetal moiety of the spirolide family of shellfish toxins is also described, making use of an iterative radical oxidative cyclization strategy.
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Daddaoua, Abdelali, Tino Krell, and Juan-Luis Ramos. "Transcriptional control by two interacting regulatory proteins: identification of the PtxS binding site at PtxR." Nucleic Acids Research 41, no. 22 (September 7, 2013): 10150–56. http://dx.doi.org/10.1093/nar/gkt773.
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Bridges, Lindsay C., Danny J. Torrent, Catalina Mosquera, and Michael R. Bard. "Chest Tube Removal in Simple Pneumothorax: Does Water-Seal Duration Matter?" American Surgeon 83, no. 8 (August 2017): 901–5. http://dx.doi.org/10.1177/000313481708300844.
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Timing of chest tube (CT) removal after transition from suction to water-seal (WS) varies when treating traumatic simple pneumothoraces (PTXs). Longer periods of WS may identify slow-occurring PTXs reducing CT replacement, whereas shorter periods may expedite patient disposition and have associated cost savings. Prior studies support the need for an interval of WS. We compare durations of WS, looking at rates of CT reinsertion. A 10-year retrospective review on trauma patients with a simple PTX requiring a CT was performed. WS duration of 1 to 8 hours (short - SG) versus 18 to 36 hours (long - LG) were compared. Univariate analysis and multivariate logistic regression were used. Of the 2000 patient charts reviewed, 209 met the criteria, with 43 in the SG and 166 in the LG. Patient demographics and mechanism of injury were similar. There was no difference in CT replacement [6.9% (SG) vs 4.8% (LG), P 0.59]. Logistic regression revealed an increase in CT replacement if the patient ever had positive pressure ventilation (OR 4.1, CI 1.1–17, P 0.04) and if returned to suction from WS (OR 6.3, CI 1.2–28, P 0.03). Short intervals of WS do not increase CT reinsertion while decreasing the total time and morbidity associated with CT.
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Bignucolo, A., C. Acton, R. Ohle, and S. Socransky. "P013: A new efficient and accurate scanning protocol for traumatic pneumothorax." CJEM 21, S1 (May 2019): S67. http://dx.doi.org/10.1017/cem.2019.204.
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Introduction: According to the International Evidence-Based Recommendations for Point-of-Care Lung Ultrasound published in 2012, the sonographic technique for evaluating a patient for a pneumothorax (PTX) “consists of exploration of the least gravitationally dependent areas progressing more laterally” in the supine patient. However, there is a wide variety of scanning protocols in the literature with varying accuracy and complexity. We sought to derive an efficient and accurate scanning protocol for diagnosing pneumothorax using point of care ultrasound in trauma. Methods: We performed a retrospective chart review of a tertiary care trauma registry from Nov 2006 to Aug 2016. We included patients with a PTX diagnosed on computed tomography (CT). Patients were excluded if they did not have an identifiable PTX on the CT scan or if they underwent a tube thoracostomy prior to the CT scan. Penetrating and blunt trauma were eligible. Data were extracted with a standardized data collection tool and 20% of charts reviewed by two reviewers. Pre defined zones were used to map area of PTXs on CT. Sensitivity, specificity and 95% CI are reported for presence of PTXs in each individual or combination of lung zones as identified on CT scan. Results: Data were collection yielded 170 traumatic PTX on chest CT with an average age of 44.2 and 77.8% male. The kappa for data extraction was 0.88. 19.4% of patients had bilateral PTX leading to a total sample size of 203. The average ISS score was 20.7 and 93% of patients survived to discharge. The length of ICU stay and hospital stay was 3.7 and 11.2 days respectively. The most accurate and efficient protocol would involve scanning the inferior border of the clavicle at the para-sternal border and again at the mid-clavicular line down to the cardiac (left hemithorax) and liver lung points (right hemithorax). The sensitivity of this scanning area in the detection of PTXs was 91.6% (95% CI 86.9-95%,). Limiting the area to the most anterior point of the chest wall increased the risk of missing a PTX (Sensitivity 89.7% (95%CI 84.6-93.5)). Conclusion: We have derived an evidence-based standardized accurate and efficient scanning protocol to rule out a pneumothorax on point of care ultrasound.
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del Castillo, Teresa, Estrella Duque, and Juan L. Ramos. "A Set of Activators and Repressors Control Peripheral Glucose Pathways in Pseudomonas putida To Yield a Common Central Intermediate." Journal of Bacteriology 190, no. 7 (February 1, 2008): 2331–39. http://dx.doi.org/10.1128/jb.01726-07.
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ABSTRACT Pseudomonas putida KT2440 channels glucose to the central Entner-Doudoroff intermediate 6-phosphogluconate through three convergent pathways. The genes for these convergent pathways are clustered in three independent regions on the host chromosome. A number of monocistronic units and operons coexist within each of these clusters, favoring coexpression of catabolic enzymes and transport systems. Expression of the three pathways is mediated by three transcriptional repressors, HexR, GnuR, and PtxS, and by a positive transcriptional regulator, GltR-2. In this study, we generated mutants in each of the regulators and carried out transcriptional assays using microarrays and transcriptional fusions. These studies revealed that HexR controls the genes that encode glucokinase/glucose 6-phosphate dehydrogenase that yield 6-phosphogluconate; the genes for the Entner-Doudoroff enzymes that yield glyceraldehyde-3-phosphate and pyruvate; and gap-1, which encodes glyceraldehyde-3-phosphate dehydrogenase. GltR-2 is the transcriptional regulator that controls specific porins for the entry of glucose into the periplasmic space, as well as the gtsABCD operon for glucose transport through the inner membrane. GnuR is the repressor of gluconate transport and gluconokinase responsible for the conversion of gluconate into 6-phosphogluconate. PtxS, however, controls the enzymes for oxidation of gluconate to 2-ketogluconate, its transport and metabolism, and a set of genes unrelated to glucose metabolism.
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Colmer, Jane A., and Abdul N. Hamood. "Molecular analysis of the Pseudomonas aeruginosa regulatory genes ptxR and ptxS." Canadian Journal of Microbiology 47, no. 9 (2001): 820–28. http://dx.doi.org/10.1139/cjm-47-9-820.
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El Sawy, Omar A. "Collaborative integration in e-business through private trading exchanges (PTXs)." Information Systems and e-Business Management 1, no. 1 (January 2003): 119–37. http://dx.doi.org/10.1007/bf02683513.
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Colmer, J. A., and A. N. Hamood. "Characterization of ptxS, a Pseudomonas aeruginosa gene which interferes with the effect of the exotoxin A positive regulatory gene, ptxR." Molecular and General Genetics MGG 258, no. 3 (May 1998): 250–59. http://dx.doi.org/10.1007/s004380050729.
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Daddaoua, Abdelali, Sandy Fillet, Matilde Fernández, Zulema Udaondo, Tino Krell, and Juan L. Ramos. "Genes for Carbon Metabolism and the ToxA Virulence Factor in Pseudomonas aeruginosa Are Regulated through Molecular Interactions of PtxR and PtxS." PLoS ONE 7, no. 7 (July 23, 2012): e39390. http://dx.doi.org/10.1371/journal.pone.0039390.
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Sun, Lei, Daming Wang, Wenjing Sun, Xiaofei Zhang, Fengjie Cui, Chang Su, Xiaomei Zhang, Guoqiang Xu, Jinsong Shi, and Zhenghong Xu. "Characterization of a transcriptional regulator PtxS from Pseudomonas plecoglossicida for regulating 2-ketogluconic acid metabolism." International Journal of Biological Macromolecules 174 (March 2021): 330–38. http://dx.doi.org/10.1016/j.ijbiomac.2021.01.198.
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Lindner, T., M. Conze, C. E. Albers, B. A. Leidel, P. Levy, C. Kleber, M. De Moya, A. Exadaktylos, and C. Stoupis. "Does Radar Technology Support the Diagnosis of Pneumothorax? PneumoScan—A Diagnostic Point-of-Care Tool." Emergency Medicine International 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/489056.
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Background. A nonrecognized pneumothorax (PTX) may become a life-threatening tension PTX. A reliable point-of-care diagnostic tool could help in reduce this risk. For this purpose, we investigated the feasibility of the use of the PneumoScan, an innovative device based on micropower impulse radar (MIR).Patients and Methods. addition to a standard diagnostic protocol including clinical examination, chest X-ray (CXR), and computed tomography (CT), 24 consecutive patients with chest trauma underwent PneumoScan testing in the shock trauma room to exclude a PTX.Results. The application of the PneumoScan was simple, quick, and reliable without functional disorder. Clinical examination and CXR each revealed one and PneumoScan three out of altogether four PTXs (sensitivity 75%, specificity 100%, positive predictive value 100%, and negative predictive value 95%). The undetected PTX did not require intervention.Conclusion. The PneumoScan as a point-of-care device offers additional diagnostic value in patient management following chest trauma. Further studies with more patients have to be performed to evaluate the diagnostic accuracy of the device.
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Rocha-Singh, Krishna J., Sue Duval, Michael R. Jaff, Peter A. Schneider, Gary M. Ansel, Sean P. Lyden, Christopher M. Mullin, et al. "Mortality and Paclitaxel-Coated Devices." Circulation 141, no. 23 (June 9, 2020): 1859–69. http://dx.doi.org/10.1161/circulationaha.119.044697.
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Background: Paclitaxel-containing devices (PTXDs) significantly reduce reintervention in patients with symptomatic femoropopliteal peripheral artery disease. A recent aggregate-data meta-analysis reported increased late mortality in patients with peripheral artery disease treated with PTXDs. We performed an individual patient data meta-analysis to evaluate mortality. Methods: Manufacturers of US Food and Drug Administration–approved and commercially available devices in the United States provided deidentified individual patient data for independent analysis. Cox proportional hazards 1-stage meta-analysis models using intention-to-treat methods were used for the primary analysis. A secondary analysis of recovered missing vital status data was performed. The impact of control crossover to PTXDs, cause-specific mortality, and drug dose mortality were assessed. Results: A total of 2185 subjects and 386 deaths from 8 PTXD trials with 4-year median follow-up were identified. The primary analysis indicated a 38% (95% CI, 6% to 80%) increased relative mortality risk, corresponding to 4.6% absolute increase, at 5 years associated with PTXD use. Control and treatment arm loss to follow-up and withdrawal were 24% and 23%, respectively. With inclusion of recovered vital status data, the excess relative mortality risk was 27% (95% CI, 3%–58%). This observation was consistent across various scenarios, including as-treated analyses, with no evidence of increased risk over time with PTXDs. Mortality risk tended to be increased for all major causes of death. There were no subgroup differences. No drug dose–mortality association was identified. Conclusions: This individual patient data meta-analysis, based on the most complete available data set of mortality events from PTXD randomized controlled trials, identified an absolute 4.6% increased mortality risk associated with PTXD use.
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Li, Dan, Jun Lin Tao, and Zhi Ping Tang. "Numerical Simulation of the Quasi-Static Axial Compression of the Pseudo-Elastic Phase Transformation Cylindrical Shells." Advanced Materials Research 378-379 (October 2011): 19–22. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.19.
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In this paper, the quasi-static axial compression of the pseudo-elastic phase transformation cylindrical shells (PTCS) is systematically investigated experimentally and numerically. Some interesting phenomena and regularities are found and in-depth understanding is gained: (i) static buckling instability properties of the PTCS with different sizes; (ⅱ) the formation and development regularities of the phase transformation hinges (PTHs). The length-diameter ratio (L/D) of the PTCS is closely related to its buckling modes.
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Torres, Marie, Alfonso Martinez-Taboas, Coralee Perez-Pedrogo, and Marisol Pena-Orellana. "3121 Potentially traumatic events and its outcomes among help-seeking adults in Puerto Rico." Journal of Clinical and Translational Science 3, s1 (March 2019): 51. http://dx.doi.org/10.1017/cts.2019.121.
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OBJECTIVES/SPECIFIC AIMS: This study aims to evaluate potentially traumatic events (PTEs) and its relationship with posttraumatic stress symptoms (PTSS), posttraumatic growth (PTG), and resilience in a sample of help-seeking individuals in Puerto Rico. METHODS/STUDY POPULATION: This is an analytic, cross sectional design. Adults receiving health services will participate in the study. Recruited participants will provide informed consent during a visit to a community mental health clinic or community hospital. They will complete a demographic document and four retrospective questionnaires about the variables of study. RESULTS/ANTICIPATED RESULTS: We expect that a high rate of potentially traumatic events (PTEs) is associated with an increased rate of posttraumatic stress symptoms (PTSS). We also expect that a high rate of PTSS is associated with an increased rate of posttraumatic growth (PTG). We expect that a high rate of resilience is associated with low rates of PTSS and PTG. DISCUSSION/SIGNIFICANCE OF IMPACT: This is a first step in the development of effective, clearly targeted interventions, specifically designed to treat negative effects, and also to facilitate positive change and resilience after PTE exposure.
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Lanctot, C., A. Moreau, M. Chamberland, M. L. Tremblay, and J. Drouin. "Hindlimb patterning and mandible development require the Ptx1 gene." Development 126, no. 9 (May 1, 1999): 1805–10. http://dx.doi.org/10.1242/dev.126.9.1805.
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The restricted expression of the Ptx1 (Pitx1) gene in the posterior half of the lateral plate mesoderm has suggested that it may play a role in specification of posterior structures, in particular, specification of hindlimb identity. Ptx1 is also expressed in the most anterior ectoderm, the stomodeum, and in the first branchial arch. Ptx1 expression overlaps with that of Ptx2 in stomodeum and in posterior left lateral plate mesoderm. We now show that targeted inactivation of the mouse Ptx1 gene severely impairs hindlimb development: the ilium and knee cartilage are absent and the long bones are underdeveloped. Greater reduction of the right femur size in Ptx1 null mice suggests partial compensation by Ptx2 on the left side. The similarly sized tibia and fibula of mutant hindlimbs may be taken to resemble forelimb bones: however, the mutant limb buds appear to have retained their molecular identity as assessed by forelimb expression of Tbx5 and by hindlimb expression of Tbx4, even though Tbx4 expression is decreased in Ptx1 null mice. The hindlimb defects appear to be, at least partly, due to abnormal chondrogenesis. Since the most affected structures derive from the dorsal side of hindlimb buds, the data suggest that Ptx1 is responsible for patterning of these dorsal structures and that as such it may control development of hindlimb-specific features. Ptx1 inactivation also leads to loss of bones derived from the proximal part of the mandibular mesenchyme. The dual role of Ptx1 revealed by the gene knockout may reflect features of the mammalian jaw and hindlimbs that were acquired at a similar time during tetrapod evolution.
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Matsushima, Ryoji, Hajime Uchida, Satoshi Nagai, Ryuichi Watanabe, Michiya Kamio, Hiroshi Nagai, Masaki Kaneniwa, and Toshiyuki Suzuki. "Assimilation, Accumulation, and Metabolism of Dinophysistoxins (DTXs) and Pectenotoxins (PTXs) in the Several Tissues of Japanese Scallop Patinopecten yessoensis." Toxins 7, no. 12 (December 1, 2015): 5141–54. http://dx.doi.org/10.3390/toxins7124870.
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Díaz, Patricio A., Gonzalo Álvarez, Gemita Pizarro, Juan Blanco, and Beatriz Reguera. "Lipophilic Toxins in Chile: History, Producers and Impacts." Marine Drugs 20, no. 2 (February 4, 2022): 122. http://dx.doi.org/10.3390/md20020122.
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A variety of microalgal species produce lipophilic toxins (LT) that are accumulated by filter-feeding bivalves. Their negative impacts on human health and shellfish exploitation are determined by toxic potential of the local strains and toxin biotransformations by exploited bivalve species. Chile has become, in a decade, the world’s major exporter of mussels (Mytilus chilensis) and scallops (Argopecten purpuratus) and has implemented toxin testing according to importing countries’ demands. Species of the Dinophysis acuminata complex and Protoceratium reticulatum are the most widespread and abundant LT producers in Chile. Dominant D. acuminata strains, notwithstanding, unlike most strains in Europe rich in okadaic acid (OA), produce only pectenotoxins, with no impact on human health. Dinophysis acuta, suspected to be the main cause of diarrhetic shellfish poisoning outbreaks, is found in the two southernmost regions of Chile, and has apparently shifted poleward. Mouse bioassay (MBA) is the official method to control shellfish safety for the national market. Positive results from mouse tests to mixtures of toxins and other compounds only toxic by intraperitoneal injection, including already deregulated toxins (PTXs), force unnecessary harvesting bans, and hinder progress in the identification of emerging toxins. Here, 50 years of LST events in Chile, and current knowledge of their sources, accumulation and effects, are reviewed. Improvements of monitoring practices are suggested, and strategies to face new challenges and answer the main questions are proposed.
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Magnotti, Louis J., Jordan A. Weinberg, Thomas J. Schroeppel, Stephanie A. Savage, Peter E. Fischer, Tiffany K. Bee, George O. Maish, et al. "Initial Chest CT Obviates the Need for Repeat Chest Radiograph after Penetrating Thoracic Trauma." American Surgeon 73, no. 6 (June 2007): 569–72. http://dx.doi.org/10.1177/000313480707300607.
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The use of serial chest radiographs (CXRs) to evaluate patients with penetrating thoracic trauma is common practice. However, the time interval between these studies and the duration of observation remains uncertain. The purpose of this study was to evaluate whether a noncontrast chest CT is as reliable as a 6-hour CXR for detecting delayed pneumothorax (PTX) after penetrating thoracic trauma. Hemodynamically stable patients with isolated penetrating thoracic trauma were prospectively evaluated with a CXR and a noncontrast chest CT. If there was no PTX or hemothorax, or a finding that did not require immediate intervention, a 6-hour CXR was obtained. Findings were treated as clinically indicated and patients were discharged if all three studies were negative. One hundred eighteen patients were evaluated (89 stab wounds and 29 gunshot wounds). All initial CXRs were negative. CT identified six PTXs and one hemothorax. Two patients required operative intervention. There were no delayed findings on CXR provided the CT was negative. The mean time to CT and before disposition was 19 minutes and 8 hours, respectively, with a potential decrease in charges of $313.32 per patient. The use of serial CXRs provided no additional information that was not available on the initial chest CT, allowing for expedited discharge, decompressing overcrowded emergency areas, and reducing the number of patients leaving before completion of their work-up.
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Miller, Jeffrey A., Sukhender Singireddy, Pierre Maldjian, and Stephen R. Baker. "A Reevaluation of the Radiographically Detectable Complications of Percutaneous Venous Access Lines Inserted by Four Subcutaneous Approaches." American Surgeon 65, no. 2 (February 1999): 125–30. http://dx.doi.org/10.1177/000313489906500206.
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As a result of prior studies elucidating the potential complications associated with the use of central venous access lines, the Food and Drug Administration and the manufacturers themselves have published guidelines and warnings outlining these dangers and describing the safest insertion techniques. We will attempt to determine whether this improved education has altered the number and type of complications, comparing the results from different types of hospitals, among the various medical services and among operators with varying degrees of experience. This is a prospective analysis of all central venous pressure (CVP) and Swanz-Ganz catheters (SGCs) inserted between July 1, 1995, and February 30, 1996, at a regional Veteran's Affairs hospital and an inner city university medical center. Three hundred seventy-five inpatients underwent 417 new percutaneous venous catheter placements while in the medical or surgical intensive care units or in the general care wards. A portable chest radiograph was obtained immediately after each procedure, and the position of the catheter and any associated complications were recorded, initially by the radiology resident in the emergency suite and subsequently as confirmed by a chest radiology attending. CVP lines were considered malpositioned when the tip was not located in the superior vena cava, and SGCs were recorded as misplaced when the tip was not found within the main, left main, right main, or either lower lobe pulmonary artery within 2 cm of the cardiac border. For patients undergoing CVP line placement, the right atrium was the most frequent site of tip malposition with 38 of 69 total misplacements (55%), whereas for SGCs, 22 of 55 malplacements (40%) were too distal in a lower lobe pulmonary artery. Only 1 of 248 CVP lines resulted in a pneumothorax (PTX; 0.4%), whereas 6 of 169 SGC insertions caused a PTX (3.5%), a significant difference (P = 0.019). Five of 192 catheters (2.6%) placed via an internal jugular approach resulted in PTX, whereas only 2 of 150 subclavian cannulations (1.3%) caused this complication, revealing a trend, but not reaching statistical significance (P = 0.473). However, there was a significant decrease in the rate of catheter misplacements in the third part of the month compared with the first 20 days (35% versus 24%; P = 0.031), and the Veteran's Affairs hospital displayed a trend toward more complications for SGC insertions than the university hospital (47% versus 32%), but not for CVP lines. In general, individual medical and surgical services displayed a similar frequency of complications (29–38%), except for CVP lines inserted in the medical intensive care unit. Venous access catheter tip malpositions are very common in all settings, but easily recognized by radiography, whereas PTXs are unusual. In contrast to most older studies, PTXs are more frequently observed with internal jugular as opposed to subclavian cannulations and with SGCs rather than CVP lines. However, our data support prior studies that the right atrium and distal right lower lobe pulmonary artery are the most common sites for CVP and SGC misplacement, respectively, and that there is an improvement in success rates with increasing operator experience.
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McDonald, Jacquelyn R., Bryan C. Jensen, Aakash Sur, Iris L. K. Wong, Stephen M. Beverley, and Peter J. Myler. "Localization of Epigenetic Markers in Leishmania Chromatin." Pathogens 11, no. 8 (August 18, 2022): 930. http://dx.doi.org/10.3390/pathogens11080930.
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Eukaryotes use histone variants and post-translation modifications (PTMs), as well as DNA base modifications, to regulate DNA replication/repair, chromosome condensation, and gene expression. Despite the unusual organization of their protein-coding genes into large polycistronic transcription units (PTUs), trypanosomatid parasites also employ a “histone code” to control these processes, but the details of this epigenetic code are poorly understood. Here, we present the results of experiments designed to elucidate the distribution of histone variants and PTMs over the chromatin landscape of Leishmania tarentolae. These experiments show that two histone variants (H2A.Z and H2B.V) and three histone H3 PTMs (H3K4me3, H3K16ac, and H3K76me3) are enriched at transcription start sites (TSSs); while a histone variant (H3.V) and the trypanosomatid-specific hyper-modified DNA base J are located at transcription termination sites (TTSs). Reduced nucleosome density was observed at all TTSs and TSSs for RNA genes transcribed by RNA polymerases I (RNAPI) or RNAPIII; as well as (to a lesser extent) at TSSs for the PTUs transcribed by RNAPII. Several PTMs (H3K4me3, H3K16ac H3K20me2 and H3K36me3) and base J were enriched at centromeres, while H3K50ac was specifically associated with the periphery of these centromeric sequences. These findings significantly expand our knowledge of the epigenetic markers associated with transcription, DNA replication and/or chromosome segregation in these early diverging eukaryotes and will hopefully lay the groundwork for future studies to elucidate how they control these fundamental processes.
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Etskovitz, Haley, Nicole Anastasio, Evangeline Green, and Meghan May. "Role of Evolutionary Selection Acting on Vaccine Antigens in the Re-Emergence of Bordetella Pertussis." Diseases 7, no. 2 (April 16, 2019): 35. http://dx.doi.org/10.3390/diseases7020035.
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Pertussis (“whooping cough”) is a re-emerging disease with increasing incidence among fully vaccinated individuals. We explored the genetic diversity of five Bordetella pertussis proteins used to generate the subunit vaccine across ancestral and newly emergent strains using immunoinformatics and evolutionary selection measurements. The five subunits of pertussis toxin (Ptx1–Ptx5) were highly conserved with regard to sequence, predicted structure, predicted antigenicity, and were under purifying selection. In contrast, the adhesin proteins pertactin (Prn) and filamentous hemagglutinin (FHA) were under statistically significant (p < 0.01) diversifying selection. Most heavily diversified sites of each protein fell within antigenic epitopes, and the functional adhesin motifs were conserved. Protein secondary structure was conserved despite sequence diversity for FHA but was changeable in Prn. These findings suggest that subunit vaccine-derived immunity does not impact Ptx1–Ptx5 but may apply evolutionary pressure to Prn and FHA to undergo diversifying selection. These findings offer further insight into the emergence of vaccine-resistant strains of B. pertussis.
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Lavingia, Kedar S., Michael C. Soult, Jay N. Collins, Timothy J. Novosel, Leonard J. Weireter, and L. D. Britt. "Basic Ultrasound Training Can Replace Chest Radiography for Safe Tube Thoracostomy Removal." American Surgeon 80, no. 8 (August 2014): 783–86. http://dx.doi.org/10.1177/000313481408000828.
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An ultrasound (US) examination can be easily and rapidly performed at the bedside to aide in clinical decisions. Previously we demonstrated that US was safe and as effective as a chest x-ray (CXR) for removal of tube thoracostomy (TT) when performed by experienced sonographers. This study sought to examine if US was as safe and accurate for the evaluation of pneumothorax (PTX) associated with TT removal after basic US training. Patients included had TT managed by the surgical team between October 2012 and May 2013. Bedside US was performed by a variety of members of the trauma team before and after removal. All residents received, at minimum, a 1-hour formal training class in the use of ultrasound. Data were collected from the electronic medical records. We evaluated 61 TTs in 61 patients during the study period. Exclusion of 12 tubes occurred secondary to having incomplete imaging, charting, or death before having TT removed. Of the 49 remaining TT, all were managed with US imaging. Average age of the patients was 40 years and 30 (61%) were male. TT was placed for PTX in 37 (76%), hemothorax in seven (14%), hemopneumothorax in four (8%), or a pleural effusion in one (2%). Two post pull PTXs were correctly identified by residents using US. This was confirmed on CXR with appropriate changes made. US was able to successfully predict the safe TT removal and patient discharge at all residency levels after receiving a basic US training program.
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MINETTI, Giampaolo, Annarita CIANA, and Cesare BALDUINI. "Differential sorting of tyrosine kinases and phosphotyrosine phosphatases acting on band 3 during vesiculation of human erythrocytes." Biochemical Journal 377, no. 2 (January 15, 2004): 489–97. http://dx.doi.org/10.1042/bj20031401.
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One of the most intensively studied post-translational modifications of erythrocyte proteins is the phosphorylation of tyrosine residues of band 3, which is strictly regulated in vivo by PTKs (protein-tyrosine kinases) and PTPs (protein-phosphotyrosine phosphatases). Two PTKs (p72syk and p56/53lyn) and two PTP activities (PTP1B and SHPTP-2) have been immunologically identified so far in mature human erythrocytes. We have shown previously that band 3 undergoes tyrosine phosphorylation upon a decrease in cell volume, as occurs when erythrocytes treated with Ca2+/Ca2+ ionophore (A23187) lose KCl and release microvesicles. Similar levels of band 3 tyrosine phosphorylation in vesicles and in the parent cells are induced by this treatment. However, we have found that tyrosine phosphorylation of band 3 in vesicles is more stable than in whole erythrocytes. Examination of how the identified PTPs and PTKs are partitioned between the vesicles and the remnant cells during vesiculation reveals that PTP1B, unlike the PTKs, is retained entirely in the parent cell compartment. Since a tight association between PTP1B and band 3 has been documented previously, we have investigated the partitioning of PTP1B and band 3 between the membrane and the membrane-skeletal fractions prepared from resting or Ca2+/A23187-treated cells. Our results rule out the possibility that the preferential retention of PTP1B within the cell was due to an increase in the amount of membrane-skeleton-associated band 3 (and of PTP1B) during the release of spectrin-free vesicles, suggesting a more complex modality of interaction of PTP1B with band 3 in the erythrocyte membrane. Analysis of erythrocytes of different cell ages revealed that PTP1B, unlike the other enzymes examined, was quantitatively conserved during erythrocyte aging. This suggests important roles for the down-regulation of tyrosine phosphorylation of band 3 in erythrocyte physiology, and for vesiculation as a mechanism of human erythrocyte senescence.
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Skar, Ane-Marthe Solheim, Tine K. Jensen, and Anna Naterstad Harpviken. "Who Reports What? A Comparison of Child and Caregivers´ Reports of Child Trauma Exposure and Associations to Post-Traumatic Stress Symptoms and Functional Impairment in Child and Adolescent Mental Health Clinics." Research on Child and Adolescent Psychopathology 49, no. 7 (February 24, 2021): 919–34. http://dx.doi.org/10.1007/s10802-021-00788-y.
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AbstractIdentifying trauma-related symptoms is important for treatment planning at child and adolescent mental health services (CAMHS), and routine trauma screening may be a first step to ensure appropriate treatment. Studies with community samples have found modest agreement between children’s and caregivers´ report of exposure to potentially traumatizing events (PTEs). However, studies from clinical populations are scarce and the evidence base for screening recommendations is insufficient. The current study explores child and caregiver agreement on the child’s exposure to PTEs and its relationship with the child’s post-traumatic stress symptoms (PTSS) and functional impairment. The sample consist of 6653 caregiver-child dyads referred to Norwegian CAMHS between 2012–2017. The children were 6 to 18 years of age (M = 12.03, SD = 3.14) and 47% were boys and 45% were girls (8% missing). Children reported significantly more exposure to accidents or illness, community violence, and sexual abuse than their caregiver, but there were no differences for reports of domestic violence. Kappa results were fair to moderate, with the highest agreement rate for reports of sexual abuse, followed by domestic violence, community violence, and lowest agreement for accidents or illnesses. There were higher agreement rates among caregivers and older children, and caregivers and girls. In general, the child had higher PTSS and functional impairment scores when child exposure to PTEs were reported by both the caregiver and the child. Both children and caregivers should be included in trauma screening procedures at CAMHS to collect a more complete picture of the child’s experiences and treatment needs.
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Kawasugi, Kazuo, Tadashi Yamamoto, Ryosuke Shirasaki, Haruko Tashiro, and Naoki Shirafuji. "Increased Levels of PTX3 in Human Plasma in Septic Patients with DIC." Blood 118, no. 21 (November 18, 2011): 4347. http://dx.doi.org/10.1182/blood.v118.21.4347.4347.
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Abstract Abstract 4347 Sepsis is a life-threatening condition that is characterized by a whole-body inflammatory state (called a systemic inflammatory response syndrome, SIRS). Long pentraxin PTX3 is an inflammatory mediator and a component of the humoral arm of innate immunity produced by neutrophils, macrophages, myeloid dendritic and endothelial cells. During sepsis a massive inflammatory activation and coagulation/fibrinolysis dysfunction occur. However, little is known about PTX3 in septic patients with DIC. Therefore, we measured PTX3s in the plasma from septic patients with DIC (n=20). Also, we investigated PTX3 in the plasma from septic patients without DIC (n=8) and acute promyelocytic leukemia (APL)-induced DIC (n=5). PTX3 in the plasma from human were measured using enzyme-linked immunosorbent assay (ELISA) kits (Perseus Proteomics Inc, Japan). The thrombin antithrombin complexes (TAT) levels were higher in both DIC patients as reported by others. We detected high levels of PTX3 in the plasma of all septic patients with DIC. Also, plasma levels of PTX3 were positive in septic patients without DIC. However, plasma levels of PTX3 were significantly higher in septic patients with DIC than in septic patients without DIC. Plasma levels of PTX3 ware significantly correlated with severity of septic DIC (platelet count and TAT level). We did not find any difference plasma levels of PTX3 in the APL patients with DIC. Moreover, high-mobility group box 1 (HMGB1) concentrations in the human plasma were determined using ELISA kit (Shino-Test, Japan). Plasma levels of HMBG1 were positive for 14 cases in 20 septic patients with DIC. Also, we did not find any difference plasma levels of HMGB1 in the APL patients with DIC. These results suggest that assess of PTX3 and HMBG1 in the plasma may be helpful in the making the diagnosis in septic patients with DIC. However, PTX3 seemed to be a better biomarker than HMGB1. It appears that PTX3 may contribute to the severity of septic DIC. Disclosures: No relevant conflicts of interest to declare.
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Wang, Bing, Serge Lemay, Schickwann Tsai, and André Veillette. "SH2 Domain-Mediated Interaction of Inhibitory Protein Tyrosine Kinase Csk with Protein Tyrosine Phosphatase-HSCF." Molecular and Cellular Biology 21, no. 4 (February 15, 2001): 1077–88. http://dx.doi.org/10.1128/mcb.21.4.1077-1088.2001.
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ABSTRACT The protein tyrosine kinase (PTK) Csk is a potent negative regulator of several signal transduction processes, as a consequence of its exquisite ability to inactivate Src-related PTKs. This function requires not only the kinase domain of Csk, but also its Src homology 3 (SH3) and SH2 regions. We showed previously that the Csk SH3 domain mediates highly specific associations with two members of the PEP family of nonreceptor protein tyrosine phosphatases (PTPs), PEP and PTP-PEST. In comparison, the Csk SH2 domain interacts with several tyrosine phosphorylated molecules, presumed to allow targetting of Csk to sites of Src family kinase activation. Herein, we attempted to understand better the regulation of Csk by identifying ligands for its SH2 domain. Using a modified yeast two-hybrid screen, we uncovered the fact that Csk associates with PTP-HSCF, the third member of the PEP family of PTPs. This association was documented not only in yeast cells but also in a heterologous mammalian cell system and in cytokine-dependent hemopoietic cells. Surprisingly, the Csk–PTP-HSCF interaction was found to be mediated by the Csk SH2 domain and two putative sites of tyrosine phosphorylation in the noncatalytic portion of PTP-HSCF. Transfection experiments indicated that Csk and PTP-HSCF synergized to inhibit signal transduction by Src family kinases and that this cooperativity was dependent on the domains mediating their association. Finally, we obtained evidence that PTP-HSCF inactivated Src-related PTKs by selectively dephosphorylating the positive regulatory tyrosine in their kinase domain. Taken together, these results demonstrate that part of the function of the Csk SH2 domain is to mediate an inducible association with a PTP, thereby engineering a more efficient inhibitory mechanism for Src-related PTKs. Coupled with previously published observations, these data also establish that Csk forms complexes with all three known members of the PEP family.
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McNabb, Paul, Andrew I. Selwood, Patrick T. Holland, J. Aasen, T. Aune, G. Eaglesham, P. Hess, et al. "Multiresidue Method for Determination of Algal Toxins in Shellfish: Single-Laboratory Validation and Interlaboratory Study." Journal of AOAC INTERNATIONAL 88, no. 3 (May 1, 2005): 761–72. http://dx.doi.org/10.1093/jaoac/88.3.761.
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Abstract A method that uses liquid chromatography with tandem mass spectrometry (LC/MS/MS) has been developed for the highly sensitive and specific determination of amnesic shellfish poisoning toxins, diarrhetic shellfish poisoning toxins, and other lipophilic algal toxins and metabolites in shellfish. The method was subjected to a full single-laboratory validation and a limited interlaboratory study. Tissue homogenates are blended with methanol-water (9 + 1), and the centrifuged extract is cleaned up with a hexane wash. LC/MS/MS (triple quadrupole) is used for quantitative analysis with reversed-phase gradient elution (acidic buffer), electrospray ionization (positive and negative ion switching), and multiple-reaction monitoring. Ester forms of dinophysis toxins are detected as the parent toxins after hydrolysis of the methanolic extract. The method is quantitative for 6 key toxins when reference standards are available: azaspiracid-1 (AZA1), domoic acid (DA), gymnodimine (GYM), okadaic acid (OA), pectenotoxin-2 (PTX2), and yessotoxin (YTX). Relative response factors are used to estimate the concentrations of other toxins: azaspiracid-2 and -3 (AZA2 and AZA3), dinophysis toxin-1 and -2 (DTX1 and DTX2), other pectenotoxins (PTX1, PTX6, and PTX11), pectenotoxin secoacid metabolites (PTX2-SA and PTX11-SA) and their 7-epimers, spirolides, and homoYTX and YTX metabolites (45-OHYTX and carboxyYTX). Validation data have been gathered for Greenshell mussel, Pacific oyster, cockle, and scallop roe via fortification and natural contamination. For the 6 key toxins at fortification levels of 0.05–0.20 mg/kg, recoveries were 71–99% and single laboratory reproducibilities, relative standard deviations (RSDs), were 10–24%. Limits of detection were <0.02 mg/kg. Extractability data were also obtained for several toxins by using successive extractions of naturally contaminated mussel samples. A preliminary interlaboratory study was conducted with a set of toxin standards and 4 mussel extracts. The data sets from 8 laboratories for the 6 key toxins plus DTX1 and DTX2 gave within-laboratories repeatability (RSDr) of 8–12%, except for PTX-2. Between-laboratories reproducibility (RSDR) values were compared with the Horwitz criterion and ranged from good to adequate for 7 key toxins (HorRat values of 0.8–2.0).
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Tremblay, Jacques J., Cynthia G. Goodyer, and Jacques Drouin. "Transcriptional Properties of Ptx1 and Ptx2 Isoforms." Neuroendocrinology 71, no. 5 (2000): 277–86. http://dx.doi.org/10.1159/000054547.
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Salas, Rafael, and Dave Clarke. "Review of DSP Toxicity in Ireland: Long-Term Trend Impacts, Biodiversity and Toxin Profiles from a Monitoring Perspective." Toxins 11, no. 2 (January 22, 2019): 61. http://dx.doi.org/10.3390/toxins11020061.
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The purpose of this work is to review all the historical monitoring data gathered by the Marine Institute, the national reference laboratory for marine biotoxins in Ireland, including all the biological and chemical data from 2005 to 2017, in relation to diarrheic shellfish poisoning (DSP) toxicity in shellfish production. The data reviewed comprises over 25,595 water samples, which were preserved in Lugol’s iodine and analysed for the abundance and composition of marine microalgae by light microscopy, and 18,166 records of shellfish flesh samples, which were analysed using LC-MS/MS for the presence and concentration of the compounds okadaic acid (OA), dinophysistoxins-1 (DTX-1), dinophysistoxins-2 (DTX-2) and their hydrolysed esters, as well as pectenotoxins (PTXs). The results of this review suggest that DSP toxicity events around the coast of Ireland occur annually. According to the data reviewed, there has not been an increase in the periodicity or intensity of such events during the study period. Although the diversity of the Dinophysis species on the coast of Ireland is large, with 10 species recorded, the two main species associated with DSP events in Ireland are D. acuta and D. acuminata. Moreover, the main toxic compounds associated with these species are OA and DTX-2, but concentrations of the hydrolysed esters are generally found in higher amounts than the parent compounds in the shellfish samples. When D. acuta is dominant in the water samples, the DSP toxicity increases in intensity, and DTX-2 becomes the prevalent toxin. Pectenotoxins have only been analysed and reported since 2012, and these compounds had not been associated with toxic events in Ireland; however, in 2014, concentrations of these compounds were quantitated for the first time, and the data suggest that this toxic event was associated with an unusually high number of observations of D. tripos that year. The areas of the country most affected by DSP outbreaks are those engaging in long-line mussel (Mytilus edulis) aquaculture.
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Lambert, Lester J., Stefan Grotegut, Maria Celeridad, Palak Gosalia, Laurent JS De Backer, Andrey A. Bobkov, Sumeet Salaniwal, et al. "Development of a Robust High-Throughput Screening Platform for Inhibitors of the Striatal-Enriched Tyrosine Phosphatase (STEP)." International Journal of Molecular Sciences 22, no. 9 (April 23, 2021): 4417. http://dx.doi.org/10.3390/ijms22094417.
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Many human diseases are the result of abnormal expression or activation of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). Not surprisingly, more than 30 tyrosine kinase inhibitors (TKIs) are currently in clinical use and provide unique treatment options for many patients. PTPs on the other hand have long been regarded as “undruggable” and only recently have gained increased attention in drug discovery. Striatal-enriched tyrosine phosphatase (STEP) is a neuron-specific PTP that is overactive in Alzheimer’s disease (AD) and other neurodegenerative and neuropsychiatric disorders, including Parkinson’s disease, schizophrenia, and fragile X syndrome. An emergent model suggests that the increase in STEP activity interferes with synaptic function and contributes to the characteristic cognitive and behavioral deficits present in these diseases. Prior efforts to generate STEP inhibitors with properties that warrant clinical development have largely failed. To identify novel STEP inhibitor scaffolds, we developed a biophysical, label-free high-throughput screening (HTS) platform based on the protein thermal shift (PTS) technology. In contrast to conventional HTS using STEP enzymatic assays, we found the PTS platform highly robust and capable of identifying true hits with confirmed STEP inhibitory activity and selectivity. This new platform promises to greatly advance STEP drug discovery and should be applicable to other PTP targets.
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Kim, Won Kon, Hyeyun Jung, Eun Young Kim, Do Hyung Kim, Yee Sook Cho, Byoung Chul Park, Sung Goo Park, Yong Ko, Kwang-Hee Bae, and Sang Chul Lee. "RPTPμ tyrosine phosphatase promotes adipogenic differentiation via modulation of p120 catenin phosphorylation." Molecular Biology of the Cell 22, no. 24 (December 15, 2011): 4883–91. http://dx.doi.org/10.1091/mbc.e11-03-0175.
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Adipocyte differentiation can be regulated by the combined activity of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). In particular, PTPs act as key regulators in differentiation-associated signaling pathways. We recently found that receptor-type PTPμ (RPTPμ) expression is markedly increased during the adipogenic differentiation of 3T3-L1 preadipocytes and mesenchymal stem cells. Here, we investigate the functional roles of RPTPμ and the mechanism of its involvement in the regulation of signal transduction during adipogenesis of 3T3-L1 cells. Depletion of endogenous RPTPμ by RNA interference significantly inhibited adipogenic differentiation, whereas RPTPμ overexpression led to an increase in adipogenic differentiation. Ectopic expression of p120 catenin suppressed adipocyte differentiation, and the decrease in adipogenesis by p120 catenin was recovered by introducing RPTPμ. Moreover, RPTPμ induced a decrease in the cytoplasmic p120 catenin expression by reducing its tyrosine phosphorylation level, consequently leading to enhanced translocation of Glut-4 to the plasma membrane. On the basis of these results, we propose that RPTPμ acts as a positive regulator of adipogenesis by modulating the cytoplasmic p120 catenin level. Our data conclusively demonstrate that differentiation into adipocytes is controlled by RPTPμ, supporting the utility of RPTPμ and p120 catenin as novel target proteins for the treatment of obesity.
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Packard, Erica R., Roger Parton, John G. Coote, and Norman K. Fry. "Sequence variation and conservation in virulence-related genes of Bordetella pertussis isolates from the UK." Journal of Medical Microbiology 53, no. 5 (May 1, 2004): 355–65. http://dx.doi.org/10.1099/jmm.0.05515-0.
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To determine the value of gene markers for surveillance and to assess the genetic stability of potential acellular pertussis vaccine components, the sequence variation in ten virulence-related genes of Bordetella pertussis was investigated in strains isolated in the UK between 1920 and 2002. These genes encode: pertactin (prnA); pertussis toxin subunits S1 (ptxA) and S3 (ptxC); tracheal colonization factor (tcfA); bordetella autotransporter protein C (bapC); bordetella resistance to killing protein (brkA); fimbrial antigen 2 (fim2); outer-membrane protein Q (ompQ); virulence-activated gene 8 (vag8) and adenylate cyclase toxin (cyaA). The encoded proteins are either components of current acellular vaccines (ACVs), or potential virulence markers for B. pertussis. Three strains used in the pertussis UK whole-cell vaccine (WCV), strain Tohama-I used for production of ACV components and the type strain of B. pertussis (18323T) were also analysed. Several novel alleles were found. The UK isolates were assigned multi-locus sequence types (MLSTs) according to a previously described scheme for B. pertussis based on three of these genes (ptxA, ptxC and tcfA). Compared with isolates from other countries, the UK clinical strains showed a distinct distribution of MLSTs. Apart from one strain that was MLST-3, all other recent isolates (2000–2002) were identified as MLST-5. These isolates differed from the three WCV strains, which were MLST-2 or MLST-3, the Tohama-I strain (MLST-2) and the type strain of B. pertussis (MLST-9). MLST-3 and MLST-5 differ only by a single synonymous mutation, but this method does indicate that currently circulating strains of B. pertussis are not identical to the vaccine types, and they may differ in other important characteristics. Two new MLSTs were identified amongst historical UK isolates. Sequence-based typing offers a convenient method of analysing and comparing populations of B. pertussis from different time periods and from different countries. The variation exhibited by prnA and fim2 suggests that they could be useful, additional epidemiological markers in such a typing scheme.
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Merciris, Patrick, Marie-Dominique Hardy-Dessources, and Françoise Giraud. "Deoxygenation of sickle cells stimulates Syk tyrosine kinase and inhibits a membrane tyrosine phosphatase." Blood 98, no. 10 (November 15, 2001): 3121–27. http://dx.doi.org/10.1182/blood.v98.10.3121.
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Abstract Polymerization of hemoglobin S in sickle red cells, in deoxygenated conditions, is associated with K+ loss and cellular dehydration. It was previously reported that deoxygenation of sickle cells increases protein tyrosine kinase (PTK) activity and band 3 tyrosine phosphorylation and that PTK inhibitors reduce cell dehydration. Here, the study investigates which PTKs are involved and the mechanism of their activation. Deoxygenation of sickle cells induced a 2-fold increase in Syk activity, measured by autophosphorylation in immune complex assays, but had no effect on Lyn. Syk was not stimulated by deoxygenation of normal red cells, and stimulation was partly reversible on reoxygenation of sickle cells. Syk activation was independent of the increase in intracellular Ca++ and Mg2+ associated with deoxygenation. Lectins that promote glycophorin or band 3 aggregation did not activate Syk. In parallel to Syk stimulation, deoxygenation of sickle cells, but not of normal red cells, decreased the activity of both membrane-associated protein tyrosine phosphatase (PTPs) and membrane protein thiol content. In vitro pretreatment of Syk immune complexes with membrane PTP inhibited Syk autophosphorylation. It is suggested that Syk activation in vivo could be mediated by PTP inhibition, itself resulting from thiol oxidation, as PTPs are known to be inhibited by oxidants. Altogether these data indicate that Syk could be involved in the mechanisms leading to sickle cell dehydration.