Quantitative increases of extracellular vesicles in prolonged cold storage of platelets increases the potential to enhance fibrin clot formation.

BACKGROUND: Platelet derived extracellular vesicles (EVs) display a pro-coagulant phenotype and are generated throughout platelet concentrate (PC) storage. Cold storage (CS) of PCs is thought to provide a superior haemostatic advantage over room temperature (RT) storage and could prolong the storage time. However, the effect of storage conditions on EV generation and PC function is unknown. We investigated EV production under CS and RT conditions and assessed whether these EVs exhibited a more pro-coagulant phenotype in model experiments. MATERIALS AND METHODS: Buffy-coat-derived PCs in a platelet additive solution (PAS) to plasma ratio of approximately 65:35 were stored at RT (22 ± 2°C) or CS (4 ± 2°C) for a prolonged storage duration of 20 days. Impedance aggregometry assessed platelet function. EVs were isolated throughout storage and quantified using nanoparticle tracking analysis. EVs were applied to a coagulation assay to assess the impact on fibrin clot formation and lysis. RESULTS: CS produced significantly larger EVs from day 4 onwards. EV concentration was significantly increased in CS compared to RT from day 15. EVs, regardless of storage, significantly reduced time to clot formation and maximum optical density measured compared to the no EV control. Clot formation was proportionate to the number of EV applied but was not statistically different across storage conditions when corrected for EV number. CONCLUSION: EVs in CS and RT units showed similar clot formation capacity. However, the higher number of larger EVs generated in CS compared to RT suggests PC units derived from CS conditions may overall exhibit a haemostatically superior capacity compared to RT storage.

Early but reversible haemostatic changes in a-symptomatic females expressing COVID-19 antibodies.

The coronavirus, COVID-19 pandemic spread across the globe in 2020, with an initial high case mortality in those requiring intensive care treatment due to serious complication. A vaccine programme was quickly developed and currently the UK is one of highest double vaccinated and boosted countries in the world. Despite tremendous efforts by the UK, new cases of COVID-19 are still occurring, due to viral mutation. A major problem associated with COVID-19 is the large a-symptomatic spread within the population. Little investigation into the a-symptomatic population has been carried out and therefore we pose that the residual effects of a-symptomatic infection is still largely unknown. Prior to mass vaccination, a multi-phased single cohort study of IgM and IgG COVID-19 antibody prevalence and the associated haemostatic changes were assessed in a Welsh cohort of 739 participants, at three time points. Positive antibody participants with age and gender matched negative antibody controls were assessed at 0, 3 and 6 months. Antibody positive females appeared to have lower antibody responses in comparison to their a-symptomatic male counterparts. Despite this initial testing showed a unique significant increase in TRAP-6-induced platelet aggregation, prothrombin time (PT) and clot initiation time. Despite coagulation parameters beginning to return to normal at 3 months, significant decreases are observed in both haemoglobin and haematocrit levels. The production of extracellular vesicles (EV) was also determined in this study. Although the overall number of EV does not change throughout the study, at the initial 0 months' time point a significant increase in the percentage of circulating pro-coagulant platelet derived EV is seen, which does not appear to be related to the extent of platelet activation in the subject. We conclude that early, but reversible changes in haemostatic pathways within the a-symptomatic, female, antibody positive COVID-19 individuals are present. These changes may be key in identifying a period of pro-coagulative risk for a-symptomatic female patients.

Exacerbated inflammatory arthritis in response to hyperactive gp130 signalling is independent of IL-17A.

OBJECTIVE: Interleukin (IL)-17A producing CD4 T-cells (TH-17 cells) are implicated in rheumatoid arthritis (RA). IL-6/STAT3 signalling drives TH-17 cell differentiation, and hyperactive gp130/STAT3 signalling in the gp130F/F mouse promotes exacerbated pathology. Conversely, STAT1-activating cytokines (eg, IL-27, IFN-γ) inhibit TH-17 commitment. Here, we evaluate the impact of STAT1 ablation on TH-17 cells during experimental arthritis and relate this to IL-17A-associated pathology. METHODS: Antigen-induced arthritis (AIA) was established in wild type (WT), gp130F/F mice displaying hyperactive gp130-mediated STAT signalling and the compound mutants gp130F/F:Stat1-/- and gp130F/F:Il17a-/- mice. Joint pathology and associated peripheral TH-17 responses were compared. RESULTS: Augmented gp130/STAT3 signalling enhanced TH-17 commitment in vitro and exacerbated joint pathology. Ablation of STAT1 in gp130F/F mice (gp130F/F:Stat1-/-) promoted the hyperexpansion of TH-17 cells in vitro and in vivo during AIA. Despite this heightened peripheral TH-17 cell response, disease severity and the number of joint-infiltrating T-cells were comparable with that of WT mice. Thus, gp130-mediated STAT1 activity within the inflamed synovium controls T-cell trafficking and retention. To determine the contribution of IL-17A, we generated gp130F/F:IL-17a-/- mice. Here, loss of IL-17A had no impact on arthritis severity. CONCLUSIONS: Exacerbated gp130/STAT-driven disease in AIA is associated with an increase in joint infiltrating T-cells but synovial pathology is IL-17A independent.

Alcohol and other risk factors for drowning among male active duty U.S. army soldiers.

BACKGROUND: Risk factors for drowning are largely undocumented among military populations. HYPOTHESIS: Accident report narratives will provide important information about the role of alcohol use and other behaviors in drownings among active duty male U.S. Army soldiers. METHODS: Using a case series design, we describe drowning deaths reported to the U.S. Army Safety Center (1980-1997), documenting associated demographic factors, alcohol use, and other risk-taking behaviors. RESULTS: Drowning victims (n = 352) were disproportionately young, black, and single, with less time-in-service, and no college experience. Most drownings occurred off-duty (89%). Alcohol use was involved in at least 31% of the cases overall. Alcohol use was also associated with a 10-fold increase in reckless behavior (OR 9.6, 95% Cl 4.5-20.7) and was most common among drownings in Europe (OR = 4.3, 95% Cl 1.5-13.4). Most drownings occurred where no lifeguard was present (68%), but almost two-thirds occurred in the presence of others, with CPR initiated in less than one-third of these cases. Drownings involving minority victims were less likely to involve alcohol, but more likely to occur in unauthorized swimming areas. While most drownings did not involve violations of safety rules, over one-third of the cases involved some form of reckless behavior, particularly for those under age 21. CONCLUSIONS: Intervention programs should be tailored to meet the needs of the demographic subgroups at highest risk since behavioral risk factors vary by race and age. CPR training and skills maintenance can improve survival rates. Narrative data are important for developing hypotheses and understanding risk factors for injuries.

Demographic, physical, and mental health factors associated with deployment of U.S. Army soldiers to the Persian Gulf.

A total of 675,626 active duty Army soldiers who were known to be at risk for deployment to the Persian Gulf were followed from 1980 through the Persian Gulf War. Hospitalization histories for the entire cohort and Health Risk Appraisal surveys for a subset of 374 soldiers were used to evaluate prewar distress, health, and behaviors. Deployers were less likely to have had any prewar hospitalizations or hospitalization for a condition commonly reported among Gulf War veterans or to report experiences of depression/suicidal ideation. Deployers reported greater satisfaction with life and relationships but displayed greater tendencies toward risk-taking, such as drunk driving, speeding, and failure to wear safety belts. Deployed veterans were more likely to receive hazardous duty pay and to be hospitalized for an injury than nondeployed Gulf War-era veterans. If distress is a predictor of postwar morbidity, it is likely attributable to experiences occurring during or after the war and not related to prewar exposures or health status. Postwar excess injury risk may be explained in part by a propensity for greater risk-taking, which was evident before and persisted throughout the war.

Audit of necropsy reporting in East Anglia.

AIMS: To establish criteria for the information to be included in a necropsy report, and to improve the quality of necropsy reporting in the Anglia Region. METHODS: Discussion between Anglia histopathologists, based on the guidelines of the Royal College of Pathologists, led to a consensus about the ideal content of a necropsy report. Fifteen consecutive necropsies subsequently undertaken by each consultant were assessed against agreed standards. Reaudit was undertaken nearly two years later, without prior announcement. RESULTS: The initial standards achieved for demographic details (70%), history (87%), external examination (43-97%), internal examination (76-95%), organ weights (73%), cause of death in OPCS format (94%), and conclusion (90%) were discussed by the group. Changes to necropsy reporting documentation were proposed. Reaudit showed improvement in nearly all categories. CONCLUSIONS: Necropsy reporting in East Anglia is currently carried out to a reasonably high standard, and improvements have occurred as a result of the audit. There was no evidence that reports on coroners' necropsies were of a lower standard than those done for the hospital. Improvement in the format of the documentation increases the likelihood that all relevant and important data are recorded.

The use of histopathology in the practice of necropsy.

AIM: To examine current practice and to establish criteria for the use of histopathology in necropsy practice. METHODS: During an audit of necropsy reporting, consensus could not be reached about the use of routine histopathology. Therefore local guidelines were formulated and current practice was compared with these guidelines. Fifteen consecutive necropsies undertaken by each consultant were reviewed and the use of histopathology noted. RESULTS: In general, the standard of necropsy reporting was reasonably high. Tissue was retained for histopathology in 25% of necropsies and 72% of these necropsy reports included a histopathology report. Using the guidelines, the assessors judged that histopathology might have been valuable in a further 19%. It was felt that routine histopathology would not have been helpful in determining the cause of death in the remaining 56%. The importance of the pathologist's clinical judgement in individual cases was stressed. At reaudit, nearly two years later, there was no significant change in practice, reflecting the lack of consensus. CONCLUSIONS: Even when histopathology might contribute to finding the cause of death, it was not always done. However, the assumption that histology is invariably helpful in determining the cause of death is challenged.

A review of pancreatico-pleural fistula in pancreatitis and its management.

Pancreatico-pleural fistula is a rare condition in which pancreatic enzymes drain directly in to the pleural cavity, most commonly from an enlarging pseudocyst. We review the literature on the causes, investigations and treatment of pancreatico-pleural fistulae and compare this with our own experience of the case of a 41 year old man with a left sided pancreatico-pleural fistula associated with pancreatic duct obstruction. The fistula could not be demonstrated by USS, CT or ERCP, and after these investigations the patient was managed conservatively. However, deterioration in the patients' condition led to an urgent but not emergency laparotomy and operative pancreatogram. This demonstrated the distally obstructed pancreatic duct, with associated pleural fistula for which aggressive surgical intervention was indicated. The patient subsequently completely recovered.

Poliovirus antibody in children from a paediatric hospital in Ibadan, Nigeria.

The immune status of 100 Nigerian children (ages 0-14) from a paediatric hospital in Ibadan, against poliovirus, after the administration of polyvalent oral poliovirus vaccine (types 1, 2 and 3) was determined using serum neutralisation test. High antibody titres were demonstrated in 78% of all the age groups tested. 57% of children under two years of age, 75% of those three to five years, and 100% of those above six years, had high poliovirus antibodies. 77% of male (47 out of 61) and 79% of female (31 out of 39) were positive. The difference between the sexes is not statistically significant (P greater than 0.05).

Diagnosis of established deep vein thrombosis with the 125 I fibrinogen uptake test.

One hundred and two patients with clinical signs indicating a possible diagnosis of deep vein thrombosis were studied with the fibrinogen uptake test and phlebography to assess the reliability of the test as a means of diagnosing established venous thrombosis. The test gave a correct diagnosis in 78% of the 85 legs shown to contain thrombus by phlebography and only 19 (10%) false-negative results in the 195 legs examined. The duration of the symptoms, the administration of anticoagulants, and mild leg swelling did not affect the accuracy of the test. Very old thrombus, phlebographically more than 11 days old, was associated with an increased false-negative rate.The fibrinogen uptake test is accurate enough to make it a valuable method of clinical investigation.