Clinical Comparison of Vascular Bleeding Time Creep Between Osseodensification and Conventional Drilling of Implant Osteotomy Sites.

This study compared the onset of vascular bleeding between osseodensification and conventional drilling of implant osteotomy sites. Patients with type III trabecular bone requiring a single missing tooth replacement were included and allocated to either Group A (test) or Group B (control). In Group A, the osseodensification group (OD), an implant osteotomy was carried out using Densah Burs (Versah) in the counterclockwise direction; in Group B, the standard drilling group (SD), Densah Burs were run in the clockwise direction. An endoscope was introduced into the osteotomy to visualize and measure the time taken for initiation of bleeding (BI) and for blood to fill the osteotomy site (BF). A total of 40 osteotomy sites (23 in the maxilla and 17 in the mandible) were included in this cross-sectional study. The mean age of study participants was 50.1 ± 8.28 years. The mean BI time for Groups A and B was 18.54 ± 2.48 seconds and 16.89 ± 1.92 seconds, respectively (P = .02); the mean BF time for Groups A and B was 41.92 ± 3.19 seconds and 37.95 ± 2.73 seconds, respectively (P < .001). Osseodensification does not seem to negatively affect or induce loss of bone vascularity. Clinicians should note that osseodensified sites might take slightly longer to fill with blood following an osteotomy.

Individual phosphatidylinositol transfer proteins have distinct functions that do not involve lipid transfer activity.

Platelets use signal transduction pathways facilitated by class I phosphatidylinositol transfer proteins (PITPs). The 2 mammalian class I PITPs, PITPα and PITPß, are single PITP domain soluble proteins that are encoded by different genes and share 77% sequence identity, although their individual roles in mammalian biology remain uncharacterized. These proteins are believed to shuttle phosphatidylinositol and phosphatidylcholine between separate intracellular membrane compartments, thereby regulating phosphoinositide synthesis and second messenger formation. Previously, we observed that platelet-specific deletion of PITPα, the predominantly expressed murine PITP isoform, had no effect on hemostasis but impaired tumor metastasis formation and disrupted phosphoinositide signaling. Here, we found that mice lacking the less expressed PITPß in their platelets exhibited a similar phenotype. However, in contrast to PITPα-null platelet lysates, which have impaired lipid transfer activity, PITPß-null platelet lysates have essentially normal lipid transfer activity, although both isoforms contribute to phosphoinositide synthesis in vitro. Moreover, we found that platelet-specific deletion of both PITPs led to ex vivo platelet aggregation/secretion and spreading defects, impaired tail bleeding, and profound tumor dissemination. Our study also demonstrated that PITP isoforms are required to maintain endogenous phosphoinositide PtdInsP2 levels and agonist-stimulated second messenger formation. The data shown here demonstrate that the 2 isoforms are functionally overlapping and that a single isoform is able to maintain the homeostasis of platelets. However, both class I PITP isoforms contribute to phosphoinositide signaling in platelets through distinct biochemical mechanisms or different subcellular domains.

Chymase Inhibition Resolves and Prevents Deep Vein Thrombosis Without Increasing Bleeding Time in the Mouse Model.

Background Deep vein thrombosis (DVT) is the primary cause of pulmonary embolism and the third most life-threatening cardiovascular disease in North America. Post-DVT anticoagulants, such as warfarin, heparin, and direct oral anticoagulants, reduce the incidence of subsequent venous thrombi. However, all currently used anticoagulants affect bleeding time at various degrees, and there is therefore a need for improved therapeutic regimens in DVT. It has recently been shown that mast cells play a crucial role in a DVT murine model. The underlying mechanism involved in the prothrombotic properties of mast cells, however, has yet to be identified. Methods and Results C57BL/6 mice and mouse mast cell protease-4 (mMCP-4) genetically depleted mice (mMCP-4 knockout) were used in 2 mouse models of DVT, partial ligation (stenosis) and ferric chloride-endothelial injury model of the inferior vena cava. Thrombus formation and impact of genetically repressed or pharmacologically (specific inhibitor TY-51469) inhibited mMCP-4 were evaluated by morphometric measurements of thrombi immunochemistry (mouse and human DVT), color Doppler ultrasound, bleeding times, and enzymatic activity assays ex vivo. Recombinant chymases, mMCP-4 (mouse) and CMA-1 (human), were used to characterize the interaction with murine and human plasmin, respectively, by mass spectrometry and enzymatic activity assays. Inhibiting mast cell-generated mMCP-4, genetically or pharmacologically, resolves and prevents venous thrombus formation in both DVT models. Inferior vena cava blood flow obstruction was observed in the stenosis model after 6 hours of ligation, in control- but not in TY-51469-treated mice. In addition, chymase inhibition had no impact on bleeding times of healthy or DVT mice. Furthermore, endogenous chymase limits plasmin activity in thrombi ex vivo. Recombinant mouse or human chymase degrades/inactivates purified plasmin in vitro. Finally, mast cell-containing immunoreactive chymase was identified in human DVT. Conclusions This study identified a major role for mMCP-4, a granule-localized protease of chymase type, in DVT formation. These findings support a novel pharmacological strategy to resolve or prevent DVT without affecting the coagulation cascade through the inhibition of chymase activity.

Effect of the arterial needle bevel position on puncture pain and postremoval bleeding time in hemodialysis patients: A self-controlled, single-blind study.

AIM: This study aimed to investigate the effect of the bevel orientation (facing upwards or downwards towards the skin) of the needle inserted into the arterial limb of the arteriovenous fistula (AVF) on puncture pain and postremoval bleeding time. METHODS: This study, using a single-blind crossover design, was conducted on 35 maintenance hemodialysis patients who had been dialyzed for at least 6 months and in whom blood access was via an AVF. AVF cannulation was performed with the needle bevel pointing upward in the first six sessions and the needle bevel pointing downwards (towards the skin) in the subsequent six sessions. Needles were always inserted in the direction of blood flow. At each dialysis session, cannulation pain was measured using a visual analog scale (VAS), and the bleeding time at the end of dialysis after needle removal was recorded. FINDINGS: The VAS score and postremoval bleeding time were lower when the needle bevel pointed downwards towards the skin during insertion (P < 0.05). DISCUSSION: Insertion of the needle with the bevel pointed downward decreased puncture pain during cannulation and bleeding time postdialysis on needle removal.

Determination of bleeding time by hounsfield unit values in computed tomography scans of patients diagnosed with intracranial hemorrhage: Evaluation results of computed tomography scans of 666 patients.

OBJECTIVE: Determining the bleeding time in intracranial hemorrhage patients is one of the most critical parameters in determining the surgical or medical treatment method. Since these are trauma patients, they are essential patients in forensic medicine. In patients where the bleeding time cannot be determined, HU value measurements in CT scans can provide quantitative data. In the radiological follow-up of the patients, only the follow-up of the bleeding volume may be misleading. METHODS: CT scans of patients diagnosed with epidural, acute subdural, and intracerebral hematoma between 2016 and 2021 were evaluated. CT scans were examined in the first 2 h, 2-6 h, 6-12 h, 12-24 h, 24-36 h, 36-48 h, 48-72 h, and 72-96 h. Each time interval obtained the lowest, highest, and average HU values. HU value ranges were defined as the heterogeneity index within the same CT scan. RESULTS: CT scans of 666 patients were evaluated. In patients with extra-axial hematoma, it was determined that the heterogeneity index increased over time. It was observed that the HU value decreased most slowly in the central part in intra-axial hemorrhages. CONCLUSIONS: HU value measurements in CT imaging can provide quantitative bleeding time and process data. Evaluating only the volumetric increase of the hematoma radiologically may cause erroneous results. HU value measurements are the most rational indicator of new bleeding.

An Investigation of ABO Blood Type and the Platelet Delta Granule Storage Pool.

Individuals with bleeding tendencies are more likely to have blood type O than blood types A, B, or AB. Platelet storage pool deficiencies are a lesser-known group of bleeding disorders which often go undiagnosed and may account for a significant number of patients with unexplained bleeding defects. We hypothesized that patients with platelet δ-storage pool deficiency might also have a predominance of type O blood. A retrospective review of medical records of 2,020 patients with unexplained bleeding and evaluated for δ-storage pool deficiency was performed. Correlations between dense granule numbers, blood type, and von Willebrand factor were analyzed for statistical differences. 51.5% of blood samples were blood type O compared to an incidence of 44.0% in the U.S. population. There was a significant association of vWF and blood type O but not with the delta storage pool. There is a preponderance of blood type O in the study population compared to the U.S. population. There is no statistically significant link between blood type O and lower dense granule numbers in this study.

Clopidogrel-herb Interactions: A Pharmacokinetic and Pharmacodynamic Assessment in a Rat Model.

BACKGROUND: Herbs usually contain a mixture of biologically active constituents, which can interact with numerous prescribed drugs and alter their safety profiles. OBJECTIVES: The current investigation was aimed to evaluate the effect of commonly used herbal products including black seed (Nigella sativa), garden cress (Lepidium sativum), and fenugreek (Trigonella foenum-graecum) on the pharmacokinetics and pharmacodynamics of clopidogrel using a Wistar rat model. METHODS: A GC-MS analysis revealed the presence of several phytoconstitutents (polyphenols) in the extracts of black seed, garden cress, and fenugreek. These polyphenols have the potential to interfere with clopidogrel effect. Plasma concentrations of clopidogrel were measured at different time points in the absence and presence of the concurrent use of tested herbal products and the pharmacokinetic parameters were calculated. Bleeding time was measured in various groups as a measure of the antiplatelet effect of clopidogrel. RESULTS: Area under the plasma concentration-time curves (AUC0-∞) of clopidogrel were 35.53 ±0.89 µg/ml*h (p<0.05), 26.01 ±0.90 µg/ml*h (p>0.05) and 32.80 ±2.51 µg/ml*h (p<0.05) in the black seed, garden cress and fenugreek group, respectively, compared with that of the control group (27.02 ±0.42 µg/ml*h). Treatment with black seed also caused an increase in clopidogrel Cmax by 31.52% (p<0.05) and with fenugreek by 21.42% (p<0.05); Cmax, did not changed with garden cress treatment (6.48 ±0.15 µg/ml versus 6.12 ±0.21 µg/ml, p>0.05). The pharmacodynamic evaluation of the antiplatelet effect of clopidogrel in the presence of herbal products treatment showed a significant prolongation in the bleeding time from a control baseline by ~22-26%, and by added ~8-12% in reference to clopidogrel therapeutic effect (p<0.05). CONCLUSION: The concurrent use of black seed, fenugreek, or garden cress can alter the pharmacokinetics and pharmacodynamics of clopidogrel to varying degrees due to the presence of various bioactive polyphenols. This is probably due to changes in drug disposition and its antiplatelet action. Further confirmation can determine the clinical relevance of these observations and identify the exact constituents responsible for such activities.

Hemostasia en fístulas arteriovenosas: comparación de la presión manual con la ejercida por un dispositivo regulable / Hemostasis of arteriovenous fistula: Comparison of direct two-finger pressure to an adjustable device

Antecedentes y objetivo: Valorar la presión generada por una pinza ajustable en fístulas arteriovenosas (FAV) durante el proceso de hemostasia y compararla con la generada por la compresión manual. Evaluar las variaciones de la compresión manual durante el proceso de hemostasia. Métodos: Se analizaron los datos de 51 sesiones de hemodiálisis de 15 pacientes. Se utilizó la presión intraacceso como indicador indirecto de la presión generada por ambos métodos sobre la FAV. La misma se registró antes de retirar la aguja venosa (PBasal), tras retirar la aguja y colocar la pinza (P1), tras ajustar la pinza (P2), al comenzar el paciente a ejercer compresión manual (M0), a los 3min del inicio de la presión manual (M3) y a los 6min del inicio de la presión manual (M6). Resultados: La presión intraacceso fue menor al aplicar la pinza y ajustarla (P2) que al aplicar presión manual (M0), con una diferencia media de −9,43mmHg (variación −18,57%, IC95%: −14,09 a −4,77mmHg, p<0,001). La presión manual mostró una tendencia descendente durante el proceso de hemostasia (M3-M0: −8,82mmHg, p<0,001; M6-M0: −12,55mmHg, p<0,001). Conclusión: La compresión ejercida por una pinza ajustable es inferior o similar a la ejercida de forma manual por el paciente. Esta última muestra una intensidad decreciente durante el proceso de hemostasia. Estos datos sugieren que algunas de las premisas sobre las que se basan algunas de las recomendaciones presentes en las guías clínicas podrían ser imprecisas. (AU)

Background and objectives: To evaluate the pressure generated by an adjustable hemostasis clamp on arteriovenous fistulas (AVF) during the hemostasis proccess, and compare it with the direct two-finger pressure applied by the patient. To evaluate the variations of the direct two-finger pressure along the hemostasis process. Methods: We analyzed data obtained in 51 hemodialysis procedures from 15 patients. AVF intra-access pressure was used as indirect indicator of the pressure generated by both methods. It was recorded before venous needle removal (PBasal), at clamp application (P1), after clamp adjustement by a nurse (P2), at the beginning of the direct two-finger pressure by the patient (M0), after 3min of two-finger pressure (M3) and after 6min of two-finger pressure (M6). Results: Intra-access pressure was lower with the adjusted clamp (P2) than with the direct two-finger pressure by the patient (M0) (variation of −18.57%, 95%CI: −14.09 to −4.77mmHg, P<.001). Intra-access pressure generated by the direct two-finger pressure method showed a decreasing trend along the hemostasis process (M3-M0: −8.82mmHg, P<.001; M6-M0: −12.55mmHg, P<.001). Conclusion: An adjustable fistula arm clamp generates a lower pressure in AVF than the direct two-finger pressure applied by the patient. The latter showed a decreasing trend along the hemostasis process. These data suggest that some of the recommendations from clinical guidelines could be based on inaccurate premises. (AU)

Characterization of the spontaneous degenerative mitral valve disease in FVB mice.

BACKGROUND: The development of new non-surgical treatments dedicated to mitral valve degeneration is limited by the absence of relevant spontaneous and rapidly progressing animal experimental models. ANIMALS: We characterized the spontaneous mitral valve degeneration in two inbred FVB mouse strains compared to C57BL/6J and investigated a contribution of the serotonergic system. METHODS: Males and females FVB/NJ and FVB/NRj were compared to the putative C57BL/6J control at 12, 16, 20 and 24 weeks of age. Body weight, systolic blood pressure, heart rate, urinary 5-hydroxyindoleacetic acid (5-HIAA), whole blood and plasma serotonin, tail bleeding time, blood cell count, plasma TGF-ß1 and plasma natriuretic peptide concentrations were measured. Myocardium and mitral valves were characterized by histology. mRNA mitral expression of 5-HT2A and 5-HT2B receptors was measured in the anterior leaflet. Cardiac anatomy and function were assessed by echocardiography. RESULTS: Compared to C57BL/6J, FVB mice strains did not significantly differ regarding body weight increase, arterial blood pressure and heart rate. A progressive augmentation of plasma pro-ANP was observed in FVB mice. Nevertheless, no cardiac hypertrophy or left-ventricular fibrosis were observed. Accordingly, plasma TGF-ß1 was not different among the three strains. Conversely, FVB mice demonstrated a high prevalence of fibromyxoid highly cellularized and enriched in glycosaminoglycans lesions, inducing major mitral leaflets thickening without increase in length. The increased thickness was correlated with urinary 5-HIAA and blood platelet count. Whole blood serotonin concentration was similar in the two strains but, in FVB, a reduction of plasma serotonin was observed together with an increase of the bleeding time. Finally, echocardiography identified left atrial and left ventricular remodeling associated with thickening of both mitral leaflets and mitral insufficient in 30% of FVB mice but no systolic protrusion of mitral leaflets towards the atrium. CONCLUSION: The FVB mouse strain is highly prone to spontaneous mitral myxomatous degeneration. A contribution of the peripheral serotonergic system is suggested.

Evaluation of Bleeding Rate and Time in Therapeutic Range in Patients Using Warfarin Before and During the COVID-19 Pandemic-Warfarin Treatment in COVID-19.

The treatment process of patients using warfarin is expected to be hindered during the COVID-19 pandemic. Therefore we investigated whether the time in therapeutic range (TTR) and bleeding complications were affected during the COVID-19 pandemic. 355 patients using warfarin were included between March 2019 to March 2021. Demographic parameters, INR (international normalized ratio), and bleeding rates were recorded retrospectively. The TTR value was calculated using Rosendaal's method. The mean age of the patients was 61 ± 12 years and 55% of them were female. The mean TTR value during the COVID-19 pandemic was lower than the pre-COVID-19 period (56 ± 21 vs 68 ± 21, P < 0.001). Among the patients, 41% had a lack of outpatient INR control. During the COVID-19 pandemic, 71 (20%) patients using VKA suffered bleeding. Among patients with bleeding, approximately 60% did not seek medical help and 6% of patients performed self-reduction of the VKA dose. During the COVID-19 pandemic, TTR values have decreased with the lack of monitoring. Furthermore, the majority of patients did not seek medical help even in case of bleeding.

Negatively charged nanoparticles of multiple materials inhibit shear-induced platelet accumulation.

Platelet accumulation by VWF under high shear rates at the site of atherosclerotic plaque rupture leads to myocardial infarction and stroke. Current anti-platelet therapies remain ineffective for a large percentage of the population, while presenting significant risks for bleeding. We explore a novel way to inhibit arterial thrombus formation. Theoretically, a negative charge may influence the tertiary structure of VWF to favor the globular configuration by biophysical means without the use of platelet inactivating drugs. We tested this hypothesis experimentally for charged nanoparticles (CNPs) to inhibit thrombus formation in a microfluidic thrombosis assay (MTA). Several different CNPs demonstrated the ability to retard thrombotic occlusion in the MTA. A preliminary study in mice shows that thrombus stability is weaker with CNP administration and bleeding times are not markedly prolonged. The CNPs tested here show promise as a new class of antithrombotic therapies that act by biophysical means rather than biochemical pathways.

Does tranexamic acid reduce risk of mortality on patients with hemoptysis?: A protocol for systematic review and meta-analysis.

BACKGROUND: Although tranexamic acid (TXA), a readily accessible antifibrinolytic agent, is widely adopted in hemorrhage scenarios, its role on mortality in patients with hemoptysis remains uncertain. New evidence is yet to be generated to evaluate the risk of mortality after using TXA in patients with hemoptysis. METHODS: PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus databases were searched from inception to May 2020. Randomized controlled trials and observational studies that evaluated the effect of TXA on patients with hemoptysis were included. Data were independently extracted by 2 reviewers and synthesized using a random-effects model. MAIN RESULTS: Five studies with a total of 20,047 patients were analyzed. When compared with the control, administration of TXA was associated with a reduction in short-term mortality (risk ratio = 0.78, 95% confidence interval [CI] 0.72-0.85; I2 = 0), shorter bleeding time (mean difference = - 24.61 hours, 95% CI - 35.96 to -13.26, I2 = 0), shorter length of hospital stay (mean difference = -1.94 days, 95% CI -2.48 to -1.40, I2 = 0), and lower need for intervention (risk ratio = 0.38, 95% CI 0.16-0.87, I2 = 0) in patients with hemoptysis. Compared with control, administration of TXA did not cause increased major or minor adverse effects. CONCLUSIONS: TXA provided benefits in terms of a lower short-term mortality rate, less bleeding time, shorter length of hospital stays, and less need for intervention in patients with hemoptysis. Use of TXA was not associated with increased adverse effects.

Nonsense-mediated mRNA decay efficiency influences bleeding severity in ITGA2B c.2659C > T (p.Q887X) knock-in mice.

Glanzmann's thrombasthenia (GT) is a severe hemorrhagic disease. It is caused by mutations in ITGA2B or ITGB3, which are the respective genes encoding integrin αIIb and ß3. Despite widespread mutational analysis, the mechanisms underlying the extensive variability in bleeding severity observed among affected individuals remains poorly understood. In order to explore the mechanisms conferring for bleeding heterogeneity, three GT patients with ITGA2B c.2671C > T (p.Q891X) who possessed different bleeding scores were studied. Analysis showed that there was significant difference in nonsense-mediated mRNA decay (NMD) efficiency among the three patients. These differences positively correlated with their bleeding score. Next, a knock-in mouse model (KI mice) with the ITGA2B c.2659C > T (p.Q887X) was generated using CRISPR/Cas9. Importantly, this mutation is homologous to ITGA2B c.2671C > T (p.Q891X) in humans. The bleeding time of KI mice was significantly in comparison to the wide-type mice. Interestingly, bleeding was stopped after treatment with caffeine, which is a known NMD inhibitor. This suggests that NMD efficiency potentially influences bleeding severity in ITGA2B c.2659C > T (p.Q887X) KI mice.

Gene therapy for hemophilia B using CB 2679d-GT: a novel factor IX variant with higher potency than factor IX Padua.

Sustained expression of therapeutic factor IX (FIX) levels has been achieved after adeno-associated viral (AAV) vector-based gene therapy in patients with hemophilia B. Nevertheless, patients are still at risk of vector dose-limiting toxicity, particularly liver inflammation, justifying the need for more efficient vectors and a lower dosing regimen. A novel increased potency FIX (designated as CB 2679d-GT), containing 3 amino acid substitutions (R318Y, R338E, T343R), significantly outperformed the R338L-Padua variant after gene therapy. CB 2679d-GT demonstrated a statistically significant approximately threefold improvement in clotting activity when compared with R338L-Padua after AAV-based gene therapy in hemophilic mice. Moreover, CB 2679d-GT gene therapy showed significantly reduced bleeding time (approximately fivefold to eightfold) and total blood loss volume (approximately fourfold) compared with mice treated with the R338L-Padua, thus achieving more rapid and robust hemostatic correction. FIX expression was sustained for at least 20 weeks with both CB 2679d-GT and R338L-Padua whereas immunogenicity was not significantly increased. This is a novel gene therapy study demonstrating the superiority of CB 2679d-GT, highlighting its potential to obtain higher FIX activity levels and superior hemostatic efficacy following AAV-directed gene therapy in hemophilia B patients than what is currently achievable with the R338L-Padua variant.

Aurka loss in CD19+ B cells promotes megakaryocytopoiesis via IL-6/STAT3 signaling-mediated thrombopoietin production.

Rationale: Aurora kinase A (Aurora-A), which is required for mitosis, is a therapeutic target in various tumors. Targeting Aurora-A led to an increase in the differentiation and polyploidization of megakaryocytes both in vivo and in vitro. However, the mechanisms involved in controlling megakaryocyte differentiation have not been fully elucidated. Methods: Conditional Aurka knockout mice were generated. B cell development, platelet development and function were subsequently examined. Proplatelet formation, in vivo response to mTPO, post-transfusion experiment, colony assay, immunofluorescence staining and quantification, and ChIP assay were conducted to gain insights into the mechanisms of Aurka loss in megakaryocytopoiesis. Results: Loss of Aurka in CD19+ B cells impaired B cell development in association with an increase in the number of platelets in peripheral blood (PB). Surprisingly, thrombopoietin (TPO) production and IL-6 were elevated in the plasma in parallel with an increase in the number of differentiated megakaryocytes in the bone marrow (BM) of Aurkaf/f;Cd19Cre/+ mice. Interestingly, compared with that of the Aurkaf/f mice, a higher number of CD19+ B cells close to megakaryocytes was observed in the BM of the Aurkaf/f;Cd19Cre/+ mice. Moreover, Aurka loss in CD19+ B cells induced signal transducer and activator of transcription-3 (STAT3) activation. Inhibition of STAT3 reduced the Tpo mRNA levels. ChIP assays revealed that STAT3 bound to the TPO promoter. Additionally, STAT3-mediated TPO transcription was an autocrine effect provoked by IL-6, at least partially. Conclusions: Deletion of Aurka in CD19+ B cells led to an increase in IL-6 production, promoting STAT3 activation, which in turn contributed to TPO transcription and megakaryocytopoiesis.

WoundClot® Hemostatic Gauze Reduces Bleeding Time after Arterial Venous Fistula Decannulation.

INTRODUCTION: Decannulation of the arteriovenous fistula (AVF) after each hemodialysis session requires a precise compression on the needle puncture site. The objective of our study was to evaluate the bleeding time (BT) needed to achieve hemostasis using WoundClot, an innovative hemostatic gauze, and to assess whether its long-term use can improve AVF preservation. METHODS: This is a prospective single center study. Initially, the time to hemostasis after AVF decannulation was compared between WoundClot and cotton gauze in 24 prevalent hemodialysis patients. Thereafter, the patients continued to use WoundClot for 12 months and were compared to a control group consisting of 25 patients using regular cotton gauze. Follow-up data included parameters of dialysis adequacy, AVF interventions, and thrombotic events. RESULTS: WoundClot use shortened significantly the time needed for hemostasis. Mean venous BT decreased by 3.99 (±4.6) min and mean arterial BT by 6.38 (±4.8) min when using WoundClot compared to cotton gauze (p < 0.001). At the end of the study, dialysis adequacy expressed by spKt/V was higher in the WoundClot group compared to control (1.73 vs. 1.53, respectively, p = 0.047). Although patients in WoundClot group had a higher baseline BT, arterial and venous pressures did not differ between the groups after a median follow up of 10.8 months. AVF thrombosis rate was similar between the groups. CONCLUSIONS: WoundClot hemostatic gauze significantly reduced the time required for hemostasis after AVF decannulation and may be associated with better AVF preservation. We suggest using WoundClot for arterial BT longer than 15 min and for venous BT longer than 12.5 min.

Endocarditis infecciosa en hospital clínico Herminda Martín de Chillán: experiencia de los últimos cinco años / Infective endocarditis at Herminda Martin clinical hospital of Chillan: last five years experience

Introducción: la endocarditis infecciosa es una afección con elevada morbilidad y mortalidad, con una incidencia en Chile de 2-3 casos por 100.000 habitantes al año, con una edad de presentación en ascenso y una clínica diversa e inespecífica que requiere un manejo multidisciplinario para el manejo de estos pacientes. Materiales y métodos: estudio observacional descriptivo, se consideró el número total de fichas clínicas del hospital clínico Herminda Martín de Chillán durante los años 2015 al 2019, con diagnóstico confirmado de endocarditis infecciosa. Los datos se registraron en la hoja de recolección de datos elaborada, realizándose los análisis estadísticos pertinentes. Resultados:la muestra (n=17) que pudo ser analizada tenía una edad promedio de 53,5 años; 70,5% (DE 14,50) fueron hombres y el agente más común identificado fue Staphylococcus aureus sensible a meticilina. En promedio los pacientes recibieron 28,8 días de antibióticos y la válvula más afectada fue la aórtica. Conclusiones: la endocarditis infecciosa es una patología con una gran morbimortalidad, que presenta un cuadro clínico inespecífico capaz de simular cualquier enfermedad. Se requieren aún de más estudios que reflejen la realidad nacional.

Introduction: Infective endocarditis is a condition with high morbidity and mortality, with an incidence in Chile of 2-3 cases per 100,000 inhabitants per year, with increasing age of presentation and a diverse and nonspecific clinic that requires multidisciplinary management for treatment of these patients. Materials and methods: Descriptive observational study, the total number of clinical records of the Herminda Martín de Chillán clinical hospital during the years 2015 to 2019, with a confirmed diagnosis of infective endocarditis, was considered. The data were recorded in the data collection sheet prepared, performing the relevant statistical analyses. Results: The sample (n = 17) that could be analysed had an average age of 53.5 years (DS 14.50), 70.5% were men, and the most common agent identified was methicillin-sensitive Staphylococcus aureus. On average, patients received 28.8 days of antibiotics, and the most affected valve was the aortic valve. Conclusions: Infective endocarditis is a pathology with high morbidity and mortality, which presents a nonspecific clinical spectrum, capable of simulating any disease. Still, more studies are required that reflect the national reality

Thrombospondin-1 promotes hemostasis through modulation of cAMP signaling in blood platelets.

Thrombospondin-1 (TSP-1) is released by platelets upon activation and can increase platelet activation, but its role in hemostasis in vivo is unclear. We show that TSP-1 is a critical mediator of hemostasis that promotes platelet activation by modulating inhibitory cyclic adenosine monophosphate (cAMP) signaling. Genetic deletion of TSP-1 did not affect platelet activation in vitro, but in vivo models of hemostasis and thrombosis showed that TSP-1-deficient mice had prolonged bleeding, defective thrombosis, and increased sensitivity to the prostacyclin mimetic iloprost. Adoptive transfer of wild-type (WT) but not TSP-1-/- platelets ameliorated the thrombotic phenotype, suggesting a key role for platelet-derived TSP-1. In functional assays, TSP-1-deficient platelets showed an increased sensitivity to cAMP signaling, inhibition of platelet aggregation, and arrest under flow by prostacyclin (PGI2). Plasma swap experiments showed that plasma TSP-1 did not correct PGI2 hypersensitivity in TSP-1-/- platelets. By contrast, incubation of TSP-1-/- platelets with releasates from WT platelets or purified TSP-1, but not releasates from TSP-1-/- platelets, reduced the inhibitory effects of PGI2. Activation of WT platelets resulted in diminished cAMP accumulation and downstream signaling, which was associated with increased activity of the cAMP hydrolyzing enzyme phosphodiesterase 3A (PDE3A). PDE3A activity and cAMP accumulation were unaffected in platelets from TSP-1-/- mice. Platelets deficient in CD36, a TSP-1 receptor, showed increased sensitivity to PGI2/cAMP signaling and diminished PDE3A activity, which was unaffected by platelet-derived or purified TSP-1. This scenario suggests that the release of TSP-1 regulates hemostasis in vivo through modulation of platelet cAMP signaling at sites of vascular injury.