The Association Between Placental Residual Blood Volume and Two Placental Transfusion Methods After Delivery at Term

Background: Despite reports of the beneficial effects, such as increasing hemoglobin level and iron store in the neonatal period, of delayed cord clamping, or umbilical cord milking after delivery in healthy term-born infants, the duration of delayed clamping or rounds of milking in most previous reports were determined arbitrarily and varied widely across different studies.Methods: We prospectively recruited 80 women with normal singleton pregnancies at 38–40 weeks' gestation. Participants were classified according to the mode of delivery and randomly assigned to either collecting blood from the placenta by umbilical cord drainage (CD) or cord milking (CM), with the placenta left in the uterus. The volume of blood collected, the duration of CD, and the number of rounds of CM were recorded.Results: Collected placental residual blood volume positively correlated with birth weight, placental weight, and length of the cord. When 80% of the total placental residual blood volume collected was set as the threshold, more than 80% of women who delivered vaginally reached this level within 60 s of CD or seven repetitions of CM. This amount of blood could be obtained within 120 s of CD or after seven repetitions of CM in more than 80% of women who underwent cesarean delivery.Conclusion: In most women, regardless of birth weight and placental weight, more than 80% of placental residual blood volume could be collected by CD within 60 s after vaginal delivery, 120 s after cesarean delivery, and seven repetitions of CM in both vaginal and cesarean deliveries.

Osteopontin as a biomarker for COVID-19 severity and multisystem inflammatory syndrome in children: A pilot study

This study sought to evaluate the candidacy of plasma osteopontin (OPN) as a biomarker of COVID-19 severity and multisystem inflammatory condition in children (MIS-C) in children. A retrospective analysis of 26 children (0–21 years of age) admitted to Children’s Healthcare of Atlanta with a diagnosis of COVID-19 between March 17 and May 26, 2020 was undertaken. The patients were classified into three categories based on COVID-19 severity levels: asymptomatic or minimally symptomatic (control population, admitted for other non-COVID-19 conditions), mild/moderate, and severe COVID-19. A fourth category of children met the Centers for Disease Control and Prevention's case definition for MIS-C. Residual blood samples were analyzed for OPN, a marker of inflammation using commercial ELISA kits (R&D), and results were correlated with clinical data. This study demonstrates that OPN levels are significantly elevated in children hospitalized with moderate and severe COVID-19 and MIS-C compared to OPN levels in mild/asymptomatic children. Further, OPN differentiated among clinical levels of severity in COVID-19, while other inflammatory markers including maximum erythrocyte sedimentation rate, C-reactive protein and ferritin, minimum lymphocyte and platelet counts, soluble interleukin-2R, and interleukin-6 did not. We conclude OPN is a potential biomarker of COVID-19 severity and MIS-C in children that may have future clinical utility. The specificity and positive predictive value of this marker for COVID-19 and MIS-C are areas for future larger prospective research studies.

Anti-IL-5 mepolizumab minimally influences residual blood eosinophils in severe asthma

Neutralising antibodies against the cytokine interleukin (IL)-5 have become widely used for the control of severe eosinophilic asthma. Remarkably, patients receiving neutralising anti-IL5 biological therapies retain a very stable population of residual blood eosinophils. Whether these residual eosinophils are endowed with particular biological activity has not yet been studied but is of importance in predicting potential long-term effects of IL5 neutralisation in patients. To tackle the effect of IL5 depletion on residual eosinophils, we used a comparative RNA-sequencing approach and compared the gene expression program of eosinophils arising in IL5-depleted or IL5-replete human or murine hosts, at steady-state in vivo and following in vitro stimulation with the eosinophil-activating alarmin IL33. We compared blood eosinophils from patients with severe allergic eosinophilic asthma treated with anti-IL5 mepolizumab therapy to those of healthy controls and matched asthma patients receiving anti-IgE omalizumab therapy. We made similar comparisons on bone marrow eosinophils from mice genetically deficient or not for IL5. We report that restriction of IL5 availability did not elicit any detectable transcriptional response in steady-state residual eosinophils in mepolizumab-treated patients or IL5-deficient mice, and influenced only a handful of genes in their response to IL33. Together, these results support the notion that treatment with IL5 neutralising antibodies spares a pool of circulating residual eosinophils largely resembling those of healthy individuals.

Mild COVID-19 and Impaired Blood Cell–Endothelial Crosstalk: Considering Long-Term Use of Antithrombotics?

Background Current coronavirus disease 2019 (COVID-19) pandemic reveals thrombotic, vascular, and endothelial dysfunctions at peak disease. However, the duration, degree of damage, and appropriate long-term use of antithrombotic strategies are unclear. Most COVID data are yielded from random clinical observations or autopsy of postmortem samples, while precise blood cellular data in survivors are insufficient. Methods We analyzed erythrocytes, circulating endothelial cells, and echinocytes by electron microscopy and flow cytometry in patients with confirmed COVID-19 (n = 31) and matched healthy controls (n = 32) on admission and at hospital discharge. Results All patients experienced mild disease, none required pulmonary support, and all survived. Admission number of circulating endothelial cells was significantly (40–100 times) higher in COVID-19 patients. Cells were massively damaged by multiple fenestrae in membranes with diameter comparable to the size of supercapsid in SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) virus. COVID-19 also provoked formation of stacked aggregated erythrocytes capable of clogging microvascular bed and of diminishing oxygen supply. In some patients, such abnormalities persisted at hospital discharge revealing remaining intracellular penetration of SARS-CoV-2 where it may be replicated and returned to circulation. Conclusion These observational and descriptive data suggest that persistent viral cell injury may cause blood vessel damage; their increased permeability resulted in tissue edema, inflammation, platelet activation, and augmented thrombosis. There is a residual blood cell damage following the acute phase in some COVID-19 survivors. Controlled outcome-driven trials are urgently needed for exploring optimal use of long-term antithrombotics and vascular protection strategies even after mild COVID-19.

The use of a novel method for SPECT/CT quantification of 99m-Tc-PYP uptake in the evaluation of ATTR cardiac amyloidosis

Funding Acknowledgements Type of funding sources: None. Background/Introduction: Bone scintigraphy with 99m-Technecium-Pyrophosphate (99m-Tc-PYP) with planar and SPECT imaging is now commonplace for the non-invasive diagnosis of ATTR cardiac amyloidosis. However, the quantification of 99m-Tc-PYP uptake is based on a semi-quantitative visual score and a heart to contralateral lung ratio which suffer from poor reproducibility. A more robust method of quantifying uptake and reporting results would be beneficial and may be possible using volumetric assessment with fused SPECT/CT acquisition. Purpose The aim of this study was to evaluate the performance of a novel semi-automated quantitative software to diagnose ATTR cardiac amyloidosis in patients with a clinical suspicion of cardiac amyloidosis who underwent 99m-Tc-PYP SPECT/CT imaging. Methods This was a retrospective, single-center study of consecutive patients who underwent 99m-Tc-PYP SPECT/CT imaging from September to December 2020. Quantification software was used to obtain standardized uptake values (SUVs) of 99m-Tc-PYP activity in the whole heart using SPECT/CT data. The total SUVs, mean SUVs, and percentage of injected tracer dose in the heart, as well as two other sets of these measurements adjusted for residual blood pool activity were obtained. Activity in the lung and bone was used to calculate heart to bone and heart to right lung ratios. The results from the software quantification were compared to the results from planar imaging as well as to the final clinical diagnosis of amyloidosis. Results A total of 59 patients were imaged during this time with an average age of 74.1 ± 11.8, and 32 (54.2%) were male. After excluding 8 patients for technical issues, 12 patients were found to be positive for amyloid, 39 were negative, and the average imaging delay time was 75.0 ± 15.2 minutes. 13 methods of assessment were evaluated with the metric of the percentage of injected tracer dose found in the heart that was adjusted for the mean residual blood pool activity having the best discrimination between abnormal and normal studies. The mean percentage of injected dose in positive patients was 2.87% vs 0.98% in the patients without amyloidosis (p < 0.0001). Using a cutoff of 2% to ensure that no patients with amyloid would be missed by screening, there was 100% sensitivity, 94.9% specificity, and 96.1% accuracy. There was a significant difference in the percentage injected dose based on gradations of planar heart to contralateral lung ratio and planar visual score. Conclusion Volumetric software quantification may be a superior method of evaluating 99m-Tc-PYP cardiac amyloidosis studies. This methodology may allow for a quantitative definition of a normal or abnormal 99m-Tc-PYP cardiac amyloid study and provide for the potential of following response to therapy.

Antibody Responses in Cats Following Primary and Annual Vaccination against Feline Immunodeficiency Virus (FIV) with an Inactivated Whole-Virus Vaccine (Fel-O-Vax® FIV)

Although the antibody response induced by primary vaccination with Fel-O-Vax® FIV (three doses, 2–4 weeks apart) is well described, the antibody response induced by annual vaccination with Fel-O-Vax® FIV (single dose every 12 months after primary vaccination) and how it compares to the primary antibody response has not been studied. Residual blood samples from a primary FIV vaccination study (n = 11), and blood samples from cats given an annual FIV vaccination (n = 10), were utilized. Samples from all 21 cats were tested with a commercially available PCR assay (FIV RealPCRTM), an anti-p24 microsphere immunoassay (MIA), an anti-FIV transmembrane (TM; gp40) peptide ELISA, and a range of commercially available point-of-care (PoC) FIV antibody kits. PCR testing confirmed all 21 cats to be FIV-uninfected for the duration of this study. Results from MIA and ELISA testing showed that both vaccination regimes induced significant antibody responses against p24 and gp40, and both anti-p24 and anti-gp40 antibodies were variably present 12 months after FIV vaccination. The magnitude of the antibody response against both p24 and gp40 was significantly higher in the primary FIV vaccination group than in the annual FIV vaccination group. The differences in prime versus recall post-vaccinal antibody levels correlated with FIV PoC kit performance. Two FIV PoC kits that detect antibodies against gp40, namely Witness® and Anigen Rapid®, showed 100% specificity in cats recently administered an annual FIV vaccination, demonstrating that they can be used to accurately distinguish vaccination and infection in annually vaccinated cats. A third FIV PoC kit, SNAP® Combo, had 0% specificity in annually FIV-vaccinated cats, and should not be used in any cat with a possible history of FIV vaccination. This study outlines the antibody response to inactivated Fel-O-Vax® FIV whole-virus vaccine, and demonstrates how best to diagnose FIV infection in jurisdictions where FIV vaccination is practiced.

5th generation vs 4th generation troponin T in predicting major adverse cardiovascular events and all-cause mortality in patients hospitalized for non-cardiac indications: A cohort study

Objective The frequency and implications of an elevated cardiac troponin (4th or 5th generation TnT) in patients outside of the emergency department or presenting with non-cardiac conditions is unclear. Methods Consecutive patients aged 18 years or older admitted for a primary non-cardiac condition who had the 4th generation TnT drawn had the 5th generation TnT run on the residual blood sample. Primary and secondary outcomes were all-cause mortality (ACM) and major adverse cardiovascular events (MACE) respectively at 1 year. Results 918 patients were included (mean age 59.8 years, 55% male) in the cohort. 69% had elevated 5th generation TnT while 46% had elevated 4th generation TnT. 5th generation TnT was more sensitive and less specific than 4th generation TnT in predicting both ACM and MACE. The sensitivities for the 5th generation TnT assay were 85% for ACM and 90% for MACE rates, compared to 65% and 70% respectively for the 4th generation assay. 5th generation TnT positive patients that were missed by 4th generation TnT had a higher risk of ACM (27.5%) than patients with both assays negative (27.5% vs 11.1%, p<0.001), but lower than patients who had both assay positive (42.1%). MACE rates were not better stratified using the 5th generation TnT assay. Conclusions In patients admitted for a non-cardiac condition, 5th generation TnT is more sensitive although less specific in predicting MACE and ACM. 5th generation TnT identifies an intermediate risk group for ACM previously missed with the 4th generation assay.

Sero-surveillance for IgG to SARS-CoV-2 at antenatal care clinics in two Kenyan referral hospitals

The high proportion of SARS-CoV-2 infections that remain undetected presents a challenge to tracking the progress of the pandemic and implementing control measures in Kenya. We determined the prevalence of IgG to SARS-CoV-2 in residual blood samples from mothers attending antenatal care services at 2 referral hospitals in Kenya. We used a validated IgG ELISA for SARS-Cov-2 spike protein and adjusted the results for assay sensitivity and specificity. In Kenyatta National Hospital, Nairobi, seroprevalence in August 2020 was 49.9% (95% CI 42.7-58.0). In Kilifi County Hospital seroprevalence increased from 1.3% (95% CI 0.04-4.7) in September to 11.0% (95% CI 6.2-16.7) in November 2020. There has been substantial, unobserved transmission of SARS-CoV-2 in parts of Nairobi and Kilifi Counties.

Increased insulin-like growth factor 1 concentrations in a retrospective population of non-diabetic cats diagnosed with hypertrophic cardiomyopathy

Objectives The aim of the study was to document whether a proportion of non-diabetic cats with left ventricular hypertrophy (LVH) previously diagnosed with hypertrophic cardiomyopathy (HCM) have elevated circulating insulin-like growth factor 1 (IGF-1) concentrations. Methods A retrospective analysis of residual blood samples obtained at the time of echocardiographic diagnosis of HCM from a population of 60 non-diabetic cats were analysed for circulating IGF-1 concentrations using a validated radioimmunoassay and compared with a control group of 16 apparently healthy cats without LVH. Clinical and echocardiographic data for cats with an IGF-1 level >1000 ng/ml were compared with those with an IGF-1 level <800 ng/ml. Results In total, 6.7% (95% confidence interval 1.8–16.2%) of cats with HCM had an IGF-1 level >1000 ng/ml. The prevalence of an IGF-1 level >1000 ng/ml in the control group was zero. Conclusions and relevance A small proportion of non-diabetic cats previously diagnosed with HCM had an IGF-1 concentration at a level that has been associated with feline hypersomatotropism (fHS) in the diabetic cat population. Further prospective research is required to confirm or refute the presence of fHS in non-diabetic cats with LVH and increased IGF-1.