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ObjectiveWe sought to determine the extent of SARS-CoV-2 seroprevalence and the factors associated with seroprevalence across a diverse cohort of healthcare workers.DesignObservational cohort study of healthcare workers, including SARS-CoV-2 serology testing and participant questionnaires.SettingsA multisite healthcare delivery system located in Los Angeles County.ParticipantsA diverse and unselected population of adults (n=6062) employed in a multisite healthcare delivery system located in Los Angeles County, including individuals with direct patient contact and others with non-patient-oriented work functions.Main outcomesUsing Bayesian and multivariate analyses, we estimated seroprevalence and factors associated with seropositivity and antibody levels, including pre-existing demographic and clinical characteristics; potential COVID-19 illness-related exposures; and symptoms consistent with COVID-19 infection.ResultsWe observed a seroprevalence rate of 4.1%, with anosmia as the most prominently associated self-reported symptom (OR 11.04, p

ImportanceCertain individuals, when infected by SARS-CoV-2, tend to develop the more severe forms of Covid-19 illness for reasons that remain unclear.ObjectiveTo determine the demographic and clinical characteristics associated with increased severity of Covid-19 infection.DesignRetrospective observational study. We curated data from the electronic health record, and used multivariable logistic regression to examine the association of pre-existing traits with a Covid-19 illness severity defined by level of required care: need for hospital admission, need for intensive care, and need for intubation.SettingA large, multihospital healthcare system in Southern California.ParticipantsAll patients with confirmed Covid-19 infection (N = 442).ResultsOf all patients studied, 48% required hospitalization, 17% required intensive care, and 12% required intubation. In multivariable-adjusted analyses, patients requiring a higher levels of care were more likely to be older (OR 1.5 per 10 years, P

To understand how kidney donation leads to an increased risk of preeclampsia, we studied pregnant outbred mice with prior uninephrectomy and compared them with sham-operated littermates carrying both kidneys. During pregnancy, uninephrectomized (UNx) mice failed to achieve a physiological increase in the glomerular filtration rate and during late gestation developed hypertension, albuminuria, glomerular endothelial damage, and excess placental production of soluble fms-like tyrosine kinase 1 (sFLT1), an antiangiogenic protein implicated in the pathogenesis of preeclampsia. Maternal hypertension in UNx mice was associated with low plasma volumes, an increased rate of fetal resorption, impaired spiral artery remodeling, and placental ischemia. To evaluate potential mechanisms, we studied plasma metabolite changes using mass spectrometry and noted that L-kynurenine, a metabolite of L-tryptophan, was upregulated approximately 3-fold during pregnancy when compared with prepregnant concentrations in the same animals, consistent with prior reports suggesting a protective role for L-kynurenine in placental health. However, UNx mice failed to show upregulation of L-kynurenine during pregnancy; furthermore, when UNx mice were fed L-kynurenine in drinking water throughout pregnancy, their preeclampsialike state was rescued, including a reversal of placental ischemia and normalization of sFLT1 levels. In aggregate, we provide a mechanistic basis for how impaired renal reserve and the resulting failure to upregulate L-kynurenine during pregnancy can lead to impaired placentation, placental hypoperfusion, an antiangiogenic state, and subsequent preeclampsia., Introduction Pregnancy is an adaptive state of net sodium and volume expansion for the purpose of increasing perfusion of the placenta and fetus. Blood flow to the uterus can increase [...]

Background24,25-Dihydroxyvitamin D [24,25(OH)2D] is a metabolite of 25-hydroxyvitamin D (25D). Blacks frequently have low total 25D without manifestations of vitamin D deficiency, suggesting that total serum 25D may incorrectly reflect vitamin D status in different racial groups. The ratio of serum 24,25(OH)2D to 25D [vitamin D metabolite ratio (VMR)] represents a new candidate biomarker for vitamin D status.MethodsWe measured 24,25(OH)2D3 and 25D3 by mass spectrometry in a random community cohort of black (n = 212) and white (n = 164) Americans to evaluate VMR as a marker for vitamin D status. We measured parathyroid hormone concentrations by immunoassay to compare VMR and 25D3 against a physiological indicator of vitamin D deficiency.ResultsSerum 24,25(OH)2D3 strongly correlated with 25D3 in both black and white study participants (r = 0.90, P < 0.001 and r = 0.86, P < 0.001 respectively). Blacks had lower mean 25D3 than whites [17.0 (7.8) vs 27.5 (11.3) ng/mL; 42.4 (19.5) vs 68.6 (28.2) nmol/L, P < 0.001] and lower mean 24,25(OH)2D3 [2.1 (1.3) vs 3.6 (2.0) ng/mL; 5.1 (3.1) vs 8.7 (4.8) nmol/L, P < 0.001]. In contrast to total 25D3 concentrations, mean VMR values were similar in blacks and whites [11.9 (4.0) vs 12.5 (3.4), P = 0.16, respectively] and were negatively correlated with parathyroid hormone concentrations in both races (rs = -0.26, P < 0.001, and rs = -0.25, P < 0.001, respectively).ConclusionsOur results provide further evidence that measurement of total 25D for assessment of vitamin D status in patients of African descent deserves reevaluation and suggest that alternative measures such as VMR should be considered.

A growing body of evidence supports an association between vitamin D and cardiovascular disease. However, the mechanisms underlying this association are unknown. From 2000 to 2002, we identified 946 participants with stable cardiovascular disease in San Francisco, California, and followed them prospectively for cardiovascular events (heart failure, myocardial infarction, stroke, or cardiovascular death). We then examined the extent to which the association was attenuated by adjustment for poor health behaviors, comorbid health conditions, and potential biological mediators. During a median follow-up period of 8.0 years (through August 24, 2012), 323 subjects (34.1%) experienced a cardiovascular event. Following adjustment for sociodemographic factors, season of blood measurement, health behaviors, and comorbid conditions, 25-hydroxyvitamin D levels under 20 ng/mL remained independently associated with cardiovascular events (hazard ratio = 1.30, 95% confidence interval: 1.01, 1.67). However, after further adjustment for potential biological mediators, the independent association was no longer present (hazard ratio = 1.11, 95% confidence interval: 0.85, 1.44). Parathyroid hormone, a potentially modifiable biological factor downstream from 25-hydroxyvitamin D, was responsible for the majority of this attenuation. These findings highlight the need for randomized controlled trials to determine whether vitamin D supplementation in persons with deficiency could be beneficial for the primary or secondary prevention of cardiovascular events.

BackgroundLow levels of total 25-hydroxyvitamin D are common among black Americans. Vitamin D-binding protein has not been considered in the assessment of vitamin D deficiency.MethodsIn the Healthy Aging in Neighborhoods of Diversity across the Life Span cohort of blacks and whites (2085 participants), we measured levels of total 25-hydroxyvitamin D, vitamin D-binding protein, and parathyroid hormone as well as bone mineral density (BMD). We genotyped study participants for two common polymorphisms in the vitamin D-binding protein gene (rs7041 and rs4588). We estimated levels of bioavailable 25-hydroxyvitamin D in homozygous participants.ResultsMean (±SE) levels of both total 25-hydroxyvitamin D and vitamin D-binding protein were lower in blacks than in whites (total 25-hydroxyvitamin D, 15.6±0.2 ng per milliliter vs. 25.8±0.4 ng per milliliter, P

Patients with end-stage kidney disease (ESKD) have increased vascular disease. While protein-bound molecules that escape hemodialysis may contribute to uremic toxicity, specific contributing toxins remain ambiguous. In this issue of the JCI, Arinze et al. explore the role of tryptophan metabolites in chronic kidney disease-associated (CKD-associated) peripheral arterial disease. The authors used mouse and zebrafish models to show that circulating indoxyl sulfate (IS) blocked endothelial Wnt signaling, which impaired angiogenesis. Plasma levels of IS and other tryptophan metabolites correlated with adverse peripheral vascular disease events in humans. These findings suggest that lowering IS may benefit individuals with CKD and ESKD., Impaired angiogenesis and excess vascular complications in uremia The use of chronic dialysis in patients with end-stage kidney disease (ESKD) is one of the miracles of modern medicine with which [...]

The article discusses the presence of autoantibodies targeting nephrin in podocytopathies, specifically minimal change disease and focal segmental glomerulosclerosis. The authors question the direct evidence of antinephrin autoantibodies in patients and suggest the need for additional controls to confirm their presence. They also highlight the presence of antinephrin autoantibodies in patients with recurrent urinary tract infections, indicating a potential novel autoimmune etiology. The study emphasizes the importance of identifying specific epitopes to improve the specificity of diagnosing idiopathic nephrotic syndrome. [Extracted from the article]

PGC1[alpha] protects against kidney injury by upregulating enzymes that enhance nicotinamide adenine dinucleotide (NAD) and driving local accumulation of the fatty acid breakdown product [beta]-hydroxybutyrate, which leads to increased production of the renoprotective prostaglandin E.sub.2. Kidney protection by PGC1[alpha] Samir Parikh and colleagues show that the mitochondrial biogenesis regulator PGC1[alpha] protects against kidney injury by regulating NAD biosynthesis. In a mouse model, PGC1[alpha] upregulates NAMPT, an enzyme required form for NAD.sup.+ biosynthesis, and drives local accumulation of the fatty acid breakdown product [beta]-hydroxybutyrate. This, in turn, leads to increased production of the renoprotective prostaglandin PGE.sub.2. The authors further show that treatment with the NAD precursor nicotinamide (NAM) can reverse established ischaemic kidney injury. The energetic burden of continuously concentrating solutes against gradients along the tubule may render the kidney especially vulnerable to ischaemia. Acute kidney injury (AKI) affects 3% of all hospitalized patients.sup.1,2. Here we show that the mitochondrial biogenesis regulator, PGC1[alpha].sup.3,4, is a pivotal determinant of renal recovery from injury by regulating nicotinamide adenine dinucleotide (NAD) biosynthesis. Following renal ischaemia, Pgc1[alpha].sup.-/- (also known as Ppargc1a.sup.-/-) mice develop local deficiency of the NAD precursor niacinamide (NAM, also known as nicotinamide), marked fat accumulation, and failure to re-establish normal function. Notably, exogenous NAM improves local NAD levels, fat accumulation, and renal function in post-ischaemic Pgc1[alpha].sup.-/- mice. Inducible tubular transgenic mice (iNephPGC1[alpha]) recapitulate the effects of NAM supplementation, including more local NAD and less fat accumulation with better renal function after ischaemia. PGC1[alpha] coordinately upregulates the enzymes that synthesize NAD de novo from amino acids whereas PGC1[alpha] deficiency or AKI attenuates the de novo pathway. NAM enhances NAD via the enzyme NAMPT and augments production of the fat breakdown product [beta]-hydroxybutyrate, leading to increased production of prostaglandin PGE.sub.2 (ref. 5), a secreted autacoid that maintains renal function. NAM treatment reverses established ischaemic AKI and also prevented AKI in an unrelated toxic model. Inhibition of [beta]-hydroxybutyrate signalling or prostaglandin production similarly abolishes PGC1[alpha]-dependent renoprotection. Given the importance of mitochondrial health in ageing and the function of metabolically active organs, the results implicate NAM and NAD as key effectors for achieving PGC1[alpha]-dependent stress resistance., Author(s): Mei T. Tran [sup.1] [sup.2] , Zsuzsanna K. Zsengeller [sup.1] [sup.2] [sup.3] , Anders H. Berg [sup.3] [sup.4] , Eliyahu V. Khankin [sup.1] [sup.2] , Manoj K. Bhasin [sup.2] [...]

We have investigated how chemistry textbooks use models of redox reactions in different subject areas, how they change models between and within the topics, and how they deal with specific learning difficulties identified in the literature. The textbooks examined were published for use in the natural science programme in Swedish upper secondary schools and in the UK A-level course. As a starting point, the defined redox models found in the literature were used to investigate the textbooks. The results show that all redox models are used with the addition of alternative representations. Authors exclusively use the electron and the oxidation number models in inorganic chemistry. In organic chemistry, the oxygen and hydrogen model are used, and in biochemistry mainly hydrogen and alternative representations. There is no guide to changes of models between the subject areas. However, within the inorganic chemistry, authors guide model change which was not identified in either organic or biochemistry. Regarding the learning difficulties, the authors dealt with just a few of them. (Contains 2 tables and 2 figures.)

Objective: Glycated hemoglobin (HbA1c) can predict risk for microvascular complications in patients with diabetes. However, HbA1c's reliability in chronic kidney disease (CKD) has been questioned, with concerns including competition from another posttranslational protein modification, carbamylation, acting on the same amino groups as glycation, and anemia with reduced erythrocyte lifespans leading to altered glycation accumulation. We investigated whether carbamylation and anemia modify the impact of HbA1c on renal outcomes in patients with diabetes and CKD.Research Design and Methods: In 1,516 participants from the Chronic Renal Insufficiency Cohort study with diabetes and CKD, Cox regression models were applied to evaluate the association between HbA1c and CKD progression (composite of end-stage kidney disease or 50% decline in estimated glomerular filtration rate [eGFR]), stratified by carbamylated albumin (C-Alb) quartiles and anemia.Results: The mean eGFR was 38.1 mL/min/1.73 m2, mean HbA1c was 7.5% (58 mmol/mol), and median C-Alb was 8.4 mmol/mol. HbA1c was lower in the higher C-Alb quartiles. During a median follow-up of 6.9 years, 763 participants experienced CKD progression. Overall, higher HbA1c was associated with an increased risk of CKD progression (adjusted hazard ratio 1.07 [95% CI 1.02-1.13]). However, using stratified analyses, HbA1c was no longer associated with CKD progression in the highest C-Alb quartile, but did show a monotonic increase in CKD progression risk across each lower C-Alb quartile (P-interaction = 0.022). Anemia also modified the association between HbA1c and CKD progression (P-interaction = 0.025).Conclusions: In patients with coexisting diabetes and CKD, the association between HbA1c and CKD progression is modified by carbamylation and anemia.Article Highlights: HbA1c's reliability in chronic kidney disease (CKD) has been questioned, with concerns including competition between carbamylation and glycation and anemia affecting glycation accumulation. We investigated whether carbamylation and anemia modify the impact of HbA1c on renal outcomes in patients with diabetes and CKD. In 1,516 participants from the Chronic Renal Insufficiency Cohort (CRIC) study with diabetes and CKD, we found that the association between HbA1c and CKD progression was significantly diminished in patients with high carbamylation levels or presence of anemia. This finding may explain why HbA1c is less reliable in patients with CKD compared with the general population with diabetes. [ABSTRACT FROM AUTHOR]

Background The multiple mutations comprising the epsilon variant demonstrate the independent convergent evolution of severe acute respiratory syndrome coronavirus (SARS-CoV-2), with its spike protein mutation L452R present in the delta (L452R), kappa (L452R), and lambda (L452Q) variants. Methods Coronavirus disease 2019 (COVID-19) variants were detected in 1017 patients using whole-genome sequencing and were assessed for outcome and severity. The mechanistic effects of the epsilon versus non-epsilon variants were investigated using a multiomic approach including cellular response assays and paired cell and host transcriptomic and proteomic profiling. Results We found that patients carrying the epsilon variant had increased mortality risk but not increased hospitalizations (P <.02). Cells infected with live epsilon compared with non-epsilon virus displayed increased sensitivity to neutralization antibodies in all patients but a slightly protective response in vaccinated individuals (P <.001). That the epsilon SARS-CoV-2 variant is more infectious but less virulent is supported mechanistically in the down-regulation of viral processing pathways seen by multiomic analyses. Importantly, this paired transcriptomics and proteomic profiling of host cellular response to live virus revealed an altered leukocyte response and metabolic messenger RNA processing with the epsilon variant. To ascertain host response to SARS-CoV-2 infection, primary COVID-19–positive nasopharyngeal samples were transcriptomically profiled and revealed a differential innate immune response (P <.001) and an adjusted T-cell response in patients carrying the epsilon variant (P <.002). In fact, patients infected with SARS-CoV-2 and those vaccinated with the BNT162b2 vaccine have comparable CD4+/CD8+ T-cell immune responses to the epsilon variant (P <.05). Conclusions While the epsilon variant is more infectious, by altering viral processing, we showed that patients with COVID-19 have adapted their innate immune response to this fitter variant. A protective T-cell response molecular signature is generated by this more transmissible variant in both vaccinated and unvaccinated patients. [ABSTRACT FROM AUTHOR]

Background: The objective of this analysis was to compare the performance sensitivity and specificity of manufacturer-recommended signal-to-cutoff (S/Co) thresholds with modified S/Co values to estimate the prevalence of SARS-CoV-2-specific antibodies in a cohort of firefighters with a known infection history. Methods: Plasma venipuncture samples were used for serologic analysis of firefighters in Los Angeles, CA, USA, in October 2020. Seropositivity was assessed using the manufacturer's recommended S/Co (≥1.4 IgG) and modified S/Co thresholds based on measured antibody levels in 178 negative control patients who had blood drawn prior to the emergence of COVID-19. Optimal S/Co threshold was determined by receiver operating characteristic (ROC) curve analysis. Results: Of 585 firefighters included in the study, 52 (8.9%) reported having a PCR-positive test history prior to antibody testing. Thirty-five (67.3%) firefighters with a previous PCR-positive test were seropositive based on the manufacturer S/Co thresholds, consistent with an estimated 67.3% sensitivity and 100% specificity. After evaluating multiple modified S/Co thresholds based on pre-pandemic negative samples, a modified S/Co of 0.36 was found to yield optimal sensitivity (88.5%) and specificity (99.4%) by ROC curve analysis. This modified threshold improved serostatus classification accuracy by 21.2%. Conclusions: S/Co thresholds based on known negative samples significantly increase seropositivity and more accurately estimate cumulative incidence of disease compared to manufacturer-based thresholds. [ABSTRACT FROM AUTHOR]

Fatty acid-binding proteins (FABPs) facilitate the diffusion of fatty acids within cellular cytoplasm. Compared with C57B1/6J mice maintained on a high-fat diet, adipose-FABP (A-FABP) null mice exhibit increased fat mass, decreased lipolysis, increased muscle glucose oxidation, and attenuated insulin resistance, whereas overexpression of epithelial-FABP (E-FABP) in adipose tissue results in decreased fat mass, increased lipolysis, and potentiated insulin resistance. To identify the mechanisms that underlie these processes, real-time PCR analyses indicate that the expression of hormone-sensitive lipase is reduced, while perilipin A is increased in A-FABP/aP2 null mice relative to E-FABP overexpressing mice. In contrast, de novo lipogenesis and expression of genes encoding lipoprotein lipase, CD36, long-chain acyl-CoA synthetase 5, and diacylglycerol acyltransferase are increased in A-FABP/aP2 null mice relative to EFABP transgenic animals. Consistent with an increase in de novo lipogenesis, there was an increase in adipose C16:0 and C16:1 acyl-.CoA pools. There were no changes in serum free fatty acids between genotypes. Serum levels of resistin were decreased in the E-FABP transgenic mice, whereas serum and tissue adiponectin were increased in A-FABP/ aP2 null mice and decreased in E-FABP transgenic animals; leptin expression was unaffected. These results suggest that the balance between lipolysis and lipogenesis in adipocytes is remodeled in the FABP null and transgenic mice and is accompanied by the reprogramming of adipokine expression in fat cells and overall changes in plasma adipokines. fatty acids; adipocytes; adipokines