5 research outputs found
Comparative assessment of physicians’ and senior medical students’ basic knowledge in treatment of chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease (COPD) is one of the most common pathologies of the respira-tory system. This disease ranks third in the group of the main causes of death in the world. The effective treatment of COPD has been developed by today. However, a significant part of physicians has an insufficient amount of education in this matter
Platelet Activation in Heparin-Induced Thrombocytopenia is Followed by Platelet Death via Complex Apoptotic and Non-Apoptotic Pathways
Heparin-induced thrombocytopenia (HIT) is an adverse drug reaction characterized by thrombocytopenia and a high risk for venous or arterial thrombosis. HIT is caused by antibodies that recognize complexes of platelet factor 4 and heparin. The pathogenic mechanisms of this condition are not fully understood. In this study, we used flow cytometry, fluorimetry, and Western blot analysis to study the direct effects of pathogenic immune complexes containing platelet factor 4 on human platelets isolated by gel-filtration. HIT-like pathogenic immune complexes initially caused pronounced activation of platelets detected by an increased expression of phosphatidylserine and P-selectin. This activation was mediated either directly through the FcγRIIA receptors or indirectly via protease-activated receptor 1 (PAR1) receptors due to thrombin generated on or near the surface of activated platelets. The immune activation was later followed by the biochemical signs of cell death, such as mitochondrial membrane depolarization, up-regulation of Bax, down-regulation of Bcl-XL, and moderate activation of procaspase 3 and increased calpain activity. The results show that platelet activation under the action of HIT-like immune complexes is accompanied by their death through complex apoptotic and calpain-dependent non-apoptotic pathways that may underlie the low platelet count in HIT
Physicians’ knowledge and preferences in tactics of management and rational pharmacotherapy of arterial hypertension in pregnant women (PHYGEST study)
Introduction: The issues of rational antihypertensive therapy in pregnant women are always extremely relevant, since high blood pressure in a pregnant woman is associated with serious risks for a mother and a fetus. The aim of the study: To determine the knowledge and preferences of physicians in the management of pregnant women with arterial hypertension. Materials and methods: A multicenter study was conducted in 2018–2021 using an anonymous questionnaire among 411 doctors from 8 regions of Russia. Results and discussion: The levels of knowledge and preferences of specialists in the issues of diagnosing and formulating a diagnosis of arterial hypertension and preeclampsia in pregnant women, prescribing basic and additional drugs for the treatment and prevention of hypertension were revealed, and the degree of compliance with the current clinical guidelines was assessed. Conclusion: Due to the insufficient level of knowledge of specialists, it is required to pay increased and special attention to this problem, strengthen control over compliance with clinical guidelines, and introduce it into postgraduate recommendations and continuing education programs
Differential Immuno-Reactivity to Genomic DNA, RNA and Mitochondrial DNA is Associated with Auto-Immunity
Background: Circulating auto-reactive antibodies are hallmark features of auto-immune diseases, however little is known with respect to the specificity of such bio-markers. In the present study, we investigated the specificity of anti-nucleic acid antibodies in the blood of subjects with systemic lupus erythematosus (SLE) and healthy controls. Methods: Sera from 12 SLE cases and 8 controls were evaluated for immuno-reactivity to purified RNA, DNA and mitochondrial DNA (mtDNA) by enzyme-linked immuno-sorbent assay (ELISA). Results: As expected, immuno-reactivity to total nucleic acids was significantly higher in subjects with SLE when compared to healthy controls, however a clear distinction was observed among the various nucleic acid sub-types, with sera from SLE subjects displaying the greatest immuno-reactivity to RNA followed by mtDNA and then total DNA. Conclusion: The identification of auto-reactive antibodies can serve as highly sensitive biomarkers, although their specificity may not always allow diagnostic certainty. The knowledge that auto-antibodies in subjects with SLE display differential immuno-reactivity may help to improve existing diagnostics and may lead to a better understanding of the pathogenesis of auto-immune disorders
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Fatal dysfunction and disintegration of thrombin-stimulated platelets.
Platelets play a key role in the formation of hemostatic clots and obstructive thrombi as well as in other biological processes. In response to physiological stimulants, including thrombin, platelets change shape, express adhesive molecules, aggregate, and secrete bioactive substances, but their subsequent fate is largely unknown. Here we examined late-stage structural, metabolic, and functional consequences of thrombin-induced platelet activation. Using a combination of confocal microscopy, scanning and transmission electron microscopy, flow cytometry, biochemical and biomechanical measurements, we showed that thrombin-induced activation is followed by time-dependent platelet dysfunction and disintegration. After ~30 minutes of incubation with thrombin, unlike with collagen or ADP, human platelets disintegrated into cellular fragments containing organelles, such as mitochondria, glycogen granules, and vacuoles. This platelet fragmentation was preceded by Ca2+ influx, integrin αIIbβ3 activation and phosphatidylserine exposure (activation phase), followed by mitochondrial depolarization, generation of reactive oxygen species, metabolic ATP depletion and impairment of platelet contractility along with dramatic cytoskeletal rearrangements, concomitant with platelet disintegration (death phase). Coincidentally with the platelet fragmentation, thrombin caused calpain activation but not activation of caspases 3 and 7. Our findings indicate that the late functional and structural damage of thrombin-activated platelets comprise a calpain-dependent platelet death pathway that shares some similarities with the programmed death of nucleated cells, but is unique to platelets, therefore representing a special form of cellular destruction. Fragmentation of activated platelets suggests that there is an underappreciated pathway of enhanced elimination of platelets from the circulation in (pro)thrombotic conditions once these cells have performed their functions