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1.
BMJ Qual Saf ; 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38782579

RESUMO

BACKGROUND: Hospital-onset bacteraemia and fungaemia (HOB) is being explored as a surveillance and quality metric. The objectives of the current study were to determine sources and preventability of HOB in hospitalised patients in the USA and to identify factors associated with perceived preventability. METHODS: We conducted a cross-sectional study of HOB events at 10 academic and three community hospitals using structured chart review. HOB was defined as a blood culture on or after hospital day 4 with growth of one or more bacterial or fungal organisms. HOB events were stratified by commensal and non-commensal organisms. Medical resident physicians, infectious disease fellows or infection preventionists reviewed charts to determine HOB source, and infectious disease physicians with training in infection prevention/hospital epidemiology rated preventability from 1 to 6 (1=definitely preventable to 6=definitely not preventable) using a structured guide. Ratings of 1-3 were collectively considered 'potentially preventable' and 4-6 'potentially not preventable'. RESULTS: Among 1789 HOB events with non-commensal organisms, gastrointestinal (including neutropenic translocation) (35%) and endovascular (32%) were the most common sources. Overall, 636/1789 (36%) non-commensal and 238/320 (74%) commensal HOB events were rated potentially preventable. In logistic regression analysis among non-commensal HOB events, events attributed to intravascular catheter-related infection, indwelling urinary catheter-related infection and surgical site infection had higher odds of being rated preventable while events with neutropenia, immunosuppression, gastrointestinal sources, polymicrobial cultures and previous positive blood culture in the same admission had lower odds of being rated preventable, compared with events without those attributes. Of 636 potentially preventable non-commensal HOB events, 47% were endovascular in origin, followed by gastrointestinal, respiratory and urinary sources; approximately 40% of those events would not be captured through existing healthcare-associated infection surveillance. DISCUSSION: Factors identified as associated with higher or lower preventability should be used to guide inclusion, exclusion and risk adjustment for an HOB-related quality metric.

3.
Nat Commun ; 15(1): 519, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38225288

RESUMO

Current treatments for T cell malignancies encounter issues of disease relapse and off-target toxicity. Using T cell receptor (TCR)Vß2 as a model, here we demonstrate the rapid generation of an off-the-shelf allogeneic chimeric antigen receptor (CAR)-T platform targeting the clone-specific TCR Vß chain for malignant T cell killing while limiting normal cell destruction. Healthy donor T cells undergo CRISPR-induced TRAC, B2M and CIITA knockout to eliminate T cell-dependent graft-versus-host and host-versus-graft reactivity. Second generation 4-1BB/CD3zeta CAR containing high affinity humanized anti-Vß scFv is expressed efficiently on donor T cells via both lentivirus and adeno-associated virus transduction with limited detectable pre-existing immunoreactivity. Our optimized CAR-T cells demonstrate specific and persistent killing of Vß2+ Jurkat cells and Vß2+ patient derived malignant T cells, in vitro and in vivo, without affecting normal T cells. In parallel, we generate humanized anti-Vß2 antibody with enhanced antibody-dependent cellular cytotoxicity (ADCC) by Fc-engineering for NK cell ADCC therapy.


Assuntos
Receptores de Antígenos de Linfócitos T , Receptores de Antígenos Quiméricos , Humanos , Receptores de Antígenos de Linfócitos T/genética , Células Jurkat , Imunoterapia Adotiva , Receptores de Antígenos Quiméricos/genética , Células Clonais
5.
JACC Heart Fail ; 11(8 Pt 1): 879-889, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37558385

RESUMO

BACKGROUND: Approximately 25% of patients admitted to hospitals for worsening heart failure (WHF) are readmitted within 30 days. OBJECTIVES: The authors conducted a post hoc analysis of the SOLOIST-WHF (Effect of Sotagliflozin on Cardiovascular Events in Patients With Type 2 Diabetes Post-WHF) trial to evaluate the efficacy of sotagliflozin versus placebo to decrease mortality and HF-related events among patients who began study treatment on or before discharge from their index hospitalization. METHODS: The main endpoint of interest was cardiovascular death or HF-related event (HF hospitalization or urgent care visit) occurring within 90 and 30 days after discharge for the index WHF hospitalization. Treatment comparisons were by proportional hazards models, generating HRs, 95% CIs, and P values. RESULTS: Of 1,222 randomized patients, 596 received study drug on or before their date of discharge. Sotagliflozin reduced the main endpoint at 90 days after discharge (HR: 0.54 [95% CI: 0.35-0.82]; P = 0.004) and at 30 days (HR: 0.49 [95% CI: 0.27-0.91]; P = 0.023) and all-cause mortality at 90 days (HR: 0.39 [95% CI: 0.17-0.88]; P = 0.024). In subgroup analyses, sotagliflozin reduced the 90-day main endpoint regardless of sex, age, estimated glomerular filtration rate, N-terminal pro-B-type natriuretic peptide, left ventricular ejection fraction, or mineralocorticoid receptor agonist use. Sotagliflozin was well-tolerated but with slightly higher rates of diarrhea and volume-related events than placebo. CONCLUSIONS: Starting sotagliflozin before discharge in patients with type 2 diabetes hospitalized for WHF significantly decreased cardiovascular deaths and HF events through 30 and 90 days after discharge, emphasizing the importance of beginning sodium glucose cotransporter treatment before discharge.


Assuntos
Diabetes Mellitus Tipo 2 , Insuficiência Cardíaca , Humanos , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hospitalização , Volume Sistólico , Função Ventricular Esquerda
6.
Nat Med ; 29(7): 1867-1876, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37330614

RESUMO

Glomerular filtration rate (GFR) decline is causally associated with kidney failure and is a candidate surrogate endpoint for clinical trials of chronic kidney disease (CKD) progression. Analyses across a diverse spectrum of interventions and populations is required for acceptance of GFR decline as an endpoint. In an analysis of individual participant data, for each of 66 studies (total of 186,312 participants), we estimated treatment effects on the total GFR slope, computed from baseline to 3 years, and chronic slope, starting at 3 months after randomization, and on the clinical endpoint (doubling of serum creatinine, GFR < 15 ml min-1 per 1.73 m2 or kidney failure with replacement therapy). We used a Bayesian mixed-effects meta-regression model to relate treatment effects on GFR slope with those on the clinical endpoint across all studies and by disease groups (diabetes, glomerular diseases, CKD or cardiovascular diseases). Treatment effects on the clinical endpoint were strongly associated with treatment effects on total slope (median coefficient of determination (R2) = 0.97 (95% Bayesian credible interval (BCI) 0.82-1.00)) and moderately associated with those on chronic slope (R2 = 0.55 (95% BCI 0.25-0.77)). There was no evidence of heterogeneity across disease. Our results support the use of total slope as a primary endpoint for clinical trials of CKD progression.


Assuntos
Falência Renal Crônica , Insuficiência Renal Crônica , Humanos , Taxa de Filtração Glomerular , Teorema de Bayes , Progressão da Doença , Biomarcadores
7.
J Am Soc Nephrol ; 34(6): 955-968, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-36918388

RESUMO

SIGNIFICANCE STATEMENT: Changes in albuminuria and GFR slope are individually used as surrogate end points in clinical trials of CKD progression, and studies have demonstrated that each is associated with treatment effects on clinical end points. In this study, the authors sought to develop a conceptual framework that combines both surrogate end points to better predict treatment effects on clinical end points in Phase 2 trials. The results demonstrate that information from the combined treatment effects on albuminuria and GFR slope improves the prediction of treatment effects on the clinical end point for Phase 2 trials with sample sizes between 100 and 200 patients and duration of follow-up ranging from 1 to 2 years. These findings may help inform design of clinical trials for interventions aimed at slowing CKD progression. BACKGROUND: Changes in log urinary albumin-to-creatinine ratio (UACR) and GFR slope are individually used as surrogate end points in clinical trials of CKD progression. Whether combining these surrogate end points might strengthen inferences about clinical benefit is unknown. METHODS: Using Bayesian meta-regressions across 41 randomized trials of CKD progression, we characterized the combined relationship between the treatment effects on the clinical end point (sustained doubling of serum creatinine, GFR <15 ml/min per 1.73 m 2 , or kidney failure) and treatment effects on UACR change and chronic GFR slope after 3 months. We applied the results to the design of Phase 2 trials on the basis of UACR change and chronic GFR slope in combination. RESULTS: Treatment effects on the clinical end point were strongly associated with the combination of treatment effects on UACR change and chronic slope. The posterior median meta-regression coefficients for treatment effects were -0.41 (95% Bayesian Credible Interval, -0.64 to -0.17) per 1 ml/min per 1.73 m 2 per year for the treatment effect on GFR slope and -0.06 (95% Bayesian Credible Interval, -0.90 to 0.77) for the treatment effect on UACR change. The predicted probability of clinical benefit when considering both surrogates was determined primarily by estimated treatment effects on UACR when sample size was small (approximately 60 patients per treatment arm) and follow-up brief (approximately 1 year), with the importance of GFR slope increasing for larger sample sizes and longer follow-up. CONCLUSIONS: In Phase 2 trials of CKD with sample sizes of 100-200 patients per arm and follow-up between 1 and 2 years, combining information from treatment effects on UACR change and GFR slope improved the prediction of treatment effects on clinical end points.


Assuntos
Insuficiência Renal Crônica , Insuficiência Renal , Humanos , Insuficiência Renal Crônica/terapia , Albuminúria/diagnóstico , Teorema de Bayes , Taxa de Filtração Glomerular , Biomarcadores , Creatinina
8.
Clin J Am Soc Nephrol ; 18(4): 446-454, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36723299

RESUMO

BACKGROUND: The cause for differences in serum creatinine between Black and non-Black individuals incorporated into prior GFR-estimating equations is not understood. We explored whether social determinants of health can account for this difference. METHODS: We conducted a secondary analysis of baseline data of the Modification of Diet in Renal Disease and Chronic Renal Insufficiency Cohort studies ( N =1628 and 1423, respectively). Data in both study cohorts were stratified by race (Black versus non-Black). We first evaluated the extent to which the coefficient of Black race in estimating GFR from creatinine is explained by correlations of race with social determinants of health and non-GFR determinants of creatinine. Second, we evaluated whether the difference between race groups in adjusted mean creatinine can be explained by social determinants of health and non-GFR determinants of creatinine. RESULTS: In models regressing measured GFR on creatinine, age, sex, and race, the coefficient for Black race was 21% (95% confidence interval, 0.176 to 0.245) in Modification of Diet in Renal Disease and 13% (95% confidence interval, 0.097 to 0.155) in the Chronic Renal Insufficiency Cohort and was not attenuated by the addition of social determinants of health, alone or in combination. In both studies, the coefficient for Black race was larger at lower versus higher income levels. In models, regressing creatinine on measured GFR, age, and sex, mean creatinine was higher in Black versus non-Black participants in both studies, with no effect of social determinants of health. CONCLUSIONS: Adjustment for selected social determinants of health did not influence the relationship between Black race and creatinine-based estimated GFR.


Assuntos
Insuficiência Renal Crônica , Determinantes Sociais da Saúde , Humanos , Creatinina , Taxa de Filtração Glomerular , Insuficiência Renal Crônica/diagnóstico , Estudos de Coortes
9.
Clin J Am Soc Nephrol ; 18(2): 183-192, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36754007

RESUMO

BACKGROUND: The GFR slope has been evaluated as a surrogate end point for kidney failure in meta-analyses on a broad collection of randomized controlled trials (RCTs) in CKD. These analyses evaluate how accurately a treatment effect on GFR slope predicts a treatment effect on kidney failure. We sought to determine whether severity of CKD in the patient population modifies the performance of GFR slope. METHODS: We performed Bayesian meta-regression analyses on 66 CKD RCTs to evaluate associations between effects on GFR slope (the chronic slope and the total slope over 3 years, expressed as mean differences in ml/min per 1.73 m2/yr) and those of the clinical end point (doubling of serum creatinine, GFR <15 ml/min per 1.73 m2, or kidney failure, expressed as a log-hazard ratio), where models allow interaction with variables defining disease severity. We evaluated three measures (baseline GFR in 10 ml/min per 1.73 m2, baseline urine albumin-to-creatinine ratio [UACR] per doubling in mg/g, and CKD progression rate defined as the control arm chronic slope, in ml/min per 1.73 m2/yr) and defined strong evidence for modification when 95% posterior credible intervals for interaction terms excluded zero. RESULTS: There was no evidence for modification by disease severity when evaluating 3-year total slope (95% credible intervals for the interaction slope: baseline GFR [-0.05 to 0.03]; baseline UACR [-0.02 to 0.04]; CKD progression rate [-0.07 to 0.02]). There was strong evidence for modification in evaluations of chronic slope (95% credible intervals: baseline GFR [0.02 to 0.11]; baseline UACR [-0.11 to -0.02]; CKD progression rate [0.01 to 0.15]). CONCLUSIONS: These analyses indicate consistency of the performance of total slope over 3 years, which provides further evidence for its validity as a surrogate end point in RCTs representing varied CKD populations.


Assuntos
Falência Renal Crônica , Insuficiência Renal Crônica , Insuficiência Renal , Humanos , Insuficiência Renal Crônica/diagnóstico , Insuficiência Renal Crônica/terapia , Insuficiência Renal Crônica/epidemiologia , Taxa de Filtração Glomerular , Biomarcadores , Progressão da Doença
11.
Blood Adv ; 7(3): 445-457, 2023 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-35947128

RESUMO

The incidence of cutaneous T-cell lymphoma (CTCL) increases with age, and blood involvement portends a worse prognosis. To advance our understanding of the development of CTCL and identify potential therapeutic targets, we performed integrative analyses of paired single-cell RNA and T-cell receptor (TCR) sequencing of peripheral blood CD4+ T cells from patients with CTCL to reveal disease-unifying features. The malignant CD4+ T cells of CTCL showed highly diverse transcriptomic profiles across patients, with most displaying a mature Th2 differentiation and T-cell exhaustion phenotype. TCR-CDR3 peptide prediction analysis suggested limited diversity between CTCL samples, consistent with a role for a common antigenic stimulus. Potential of heat diffusion for affinity-based trajectory embedding transition analysis identified putative precancerous circulating populations characterized by an intermediate stage of gene expression and mutation level between the normal CD4+ T cells and malignant CTCL cells. We further revealed the therapeutic potential of targeting CD82 and JAK that endow the malignant CTCL cells with survival and proliferation advantages.


Assuntos
Linfoma Cutâneo de Células T , Neoplasias Cutâneas , Humanos , Transcriptoma , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Linfoma Cutâneo de Células T/patologia , Linfócitos T CD4-Positivos/metabolismo , Receptores de Antígenos de Linfócitos T/genética
12.
Cells ; 11(18)2022 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-36139492

RESUMO

Albuminuria, a hallmark of diabetic nephropathy, reflects not only injury and dysfunction of the filtration apparatus, but is also affected by altered glomerular hemodynamics and hyperfiltration, as well as by the inability of renal tubular cells to fully retrieve filtered albumin. Albuminuria further plays a role in the progression of diabetic nephropathy, and the suppression of glomerular albumin leak is a key factor in its prevention. Although microalbuminuria is a classic manifestation of diabetic nephropathy, often progressing to macroalbuminuria or overt proteinuria over time, it does not always precede renal function loss in diabetes. The various components leading to diabetic albuminuria and their associations are herein reviewed, and the physiologic rationale and efficacy of therapeutic interventions that reduce glomerular hyperfiltration and proteinuria are discussed. With these perspectives, we propose that these measures should be initiated early, before microalbuminuria develops, as substantial renal injury may already be present in the absence of proteinuria. We further advocate that the inhibition of the renin-angiotensin axis or of sodium-glucose co-transport likely permits the administration of a normal recommended or even high-protein diet, highly desirable for sarcopenic diabetic patients.


Assuntos
Diabetes Mellitus , Nefropatias Diabéticas , Albuminas , Albuminúria , Angiotensinas , Glucose , Humanos , Proteinúria , Renina , Sódio
13.
Front Psychiatry ; 13: 913230, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35935412

RESUMO

The "frontal lobe paradox" highlights a phenomenon in which a subset of patients who possess frontal lobe damage and exhibit marked impairments in everyday life are still able to able to verbally describe a logical course of action relating to a task and perform well in interview and test settings. Such cases pose a challenge with regard to the assessment of mental capacity within clinical settings. Recent position articles state that the frontal lobe paradox is a well-known phenomenon within the field of neuropsychology, anecdotal reports from clinicians in the UK suggest this is not the case. Consequently, we conducted a scoping review to examine the breadth and depth of literature relating to the frontal lobe paradox. Searches were conducted using electronic databases and search engines, which were supplemented with a snowball search of the references used within relevant literature. We identified and reviewed 28 documents specifically related to the frontal lobe paradox. Nearly 50% of all identified academic texts published since 2000 were position articles that cited a handful of case studies published between 1936 and 1986 as evidence for the phenomenon. We also observed instances of articles citing position articles as evidence of the frontal lobe paradox. Overall, our findings indicate a lack of readily accessible research specific to the frontal lobe paradox. In particular, there is a lack of contemporary research specific to the subject and an absence of clarification as to which syndromes and disorders are included within the term.

15.
Kidney Med ; 4(2): 100394, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35243306

RESUMO

RATIONALE & OBJECTIVE: Thrice-weekly hemodialysis can result in adequate urea clearance; however, the morbidity and mortality rates of patients treated with maintenance dialysis remain unacceptably high, partly because of nonadherence. African Americans have a higher prevalence of kidney failure treated with dialysis, greater dialysis nonadherence, and higher odds of hospitalization. We hypothesized that more precise ways of assessing dialysis treatment adherence will reflect the severity of nonadherence, distinguish patterns of nonadherence, and inform the design of personalized behavioral interventions. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: African American patients receiving hemodialysis for >90 days. EXPOSURE: Hemodialysis. OUTCOME: Dialysis adherence. ANALYTICAL APPROACH: Dialysis attendance data were displayed using a dot plot, categorized based on missed and shortened treatments, and examined for patterns. Descriptive characteristics were reported. In an exploratory analysis, associations between dialysis treatment adherence and participant characteristics were evaluated using ordinary least squares regression. An analysis was performed using missed minutes of dialysis and current metrics for measuring dialysis treatment adherence (ie, missed and shortened treatments). RESULTS: Among 113 African American patients treated with dialysis, 47% were men; the median age was 57 years (interquartile range, 46-70 years), and the median dialysis vintage was 54 months (interquartile range, 22-90 months). With rows ordered based on the total missed minutes of dialysis, the dot plot displayed a decreasing gradient in the severity of nonadherence, with novel dialysis treatment adherence categories termed as follows: consistent underdialysis, inconsistent dialysis, and consistent dialysis. Distinct patterns of nonadherence and heterogeneity emerged within these categories. Older age was consistently associated with better adherence, as determined by the analyses performed using the total missed minutes of dialysis as well as missed and shortened treatments. LIMITATIONS: The study findings, although replicable and paradigm-shifting, might be limited by the short timeline, focus on adherence data specific to African American patients treated with dialysis, and restriction to dialysis units affiliated with 1 academic center. CONCLUSIONS: This study presents more precise and novel ways of measuring and displaying dialysis treatment adherence. The findings introduce a more personalized approach for evaluating actual dialysis uptake. Identification of unique patterns of adherence behavior is important to inform the design of effective behavioral interventions and improve outcomes for vulnerable African American patients treated with dialysis.

16.
J Card Fail ; 28(1): 21-31, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34403831

RESUMO

BACKGROUND: The concept of multinephron segment diuretic therapy (MSDT) has been recommended in severe diuretic resistance with only expert opinion and case-level evidence. The purpose of this study was to investigate the safety and efficacy of MSDT, combining 4 diuretic classes, in acute heart failure (AHF) complicated by diuretic resistance. METHODS AND RESULTS: A retrospective analysis was conducted in patients hospitalized with AHF at a single medical center who received MSDT, including concomitant carbonic anhydrase inhibitor, loop, thiazide, and mineralocorticoid receptor antagonist diuretics. Subjects served as their own controls with efficacy evaluated as urine output and weight change before and after MSDT. Serum chemistries, renal replacement therapies, and in-hospital mortality were evaluated for safety. Patients with severe diuretic resistance before MSDT were analyzed as a subcohort. A total of 167 patients with AHF and diuretic resistance received MSDT. MSDT was associated with increased median 24-hour urine output in the first day of therapy compared with the previous day (2.16 L [0.95-4.14 L] to 3.08 L [1.74-4.86 L], P = .003) in the total cohort and in the Severe diuretic resistance cohort (0.91 L [0.43-1.43 L] to 2.08 L [1.13-3.96 L], P < .001). The median cumulative weight loss at day 7 or discharge was -7.4 kg (-15.3 to -3.4 kg) (P = .02). Neither serum sodium, chloride, potassium, bicarbonate, or creatinine changed significantly relative to baseline (P > .05 for all). CONCLUSIONS: In an AHF cohort with diuretic resistance, MSDT was associated with increased diuresis without changes in serum chemistries or kidney function. Prospective studies of MSDT in AHF and diuretic resistance are warranted.


Assuntos
Diuréticos , Insuficiência Cardíaca , Doença Aguda , Diuréticos/farmacologia , Humanos , Antagonistas de Receptores de Mineralocorticoides , Estudos Prospectivos , Estudos Retrospectivos , Inibidores de Simportadores de Cloreto de Sódio e Potássio
18.
J Am Soc Nephrol ; 33(2): 291-303, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34862238

RESUMO

BACKGROUND: Acute changes in GFR can occur after initiation of interventions targeting progression of CKD. These acute changes complicate the interpretation of long-term treatment effects. METHODS: To assess the magnitude and consistency of acute effects in randomized clinical trials and explore factors that might affect them, we performed a meta-analysis of 53 randomized clinical trials for CKD progression, enrolling 56,413 participants with at least one estimated GFR measurement by 6 months after randomization. We defined acute treatment effects as the mean difference in GFR slope from baseline to 3 months between randomized groups. We performed univariable and multivariable metaregression to assess the effect of intervention type, disease state, baseline GFR, and albuminuria on the magnitude of acute effects. RESULTS: The mean acute effect across all studies was -0.21 ml/min per 1.73 m2 (95% confidence interval, -0.63 to 0.22) over 3 months, with substantial heterogeneity across interventions (95% coverage interval across studies, -2.50 to +2.08 ml/min per 1.73 m2). We observed negative average acute effects in renin angiotensin system blockade, BP lowering, and sodium-glucose cotransporter 2 inhibitor trials, and positive acute effects in trials of immunosuppressive agents. Larger negative acute effects were observed in trials with a higher mean baseline GFR. CONCLUSION: The magnitude and consistency of acute GFR effects vary across different interventions, and are larger at higher baseline GFR. Understanding the nature and magnitude of acute effects can help inform the optimal design of randomized clinical trials evaluating disease progression in CKD.


Assuntos
Taxa de Filtração Glomerular/efeitos dos fármacos , Insuficiência Renal Crônica/tratamento farmacológico , Insuficiência Renal Crônica/fisiopatologia , Albuminúria/tratamento farmacológico , Albuminúria/urina , Anti-Hipertensivos/uso terapêutico , Creatinina/urina , Progressão da Doença , Feminino , Humanos , Imunossupressores/uso terapêutico , Masculino , Ensaios Clínicos Controlados Aleatórios como Assunto , Sistema Renina-Angiotensina/efeitos dos fármacos , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico
19.
Glomerular Dis ; 2(2): 75-82, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36751533

RESUMO

Introduction: Anti-phospholipase A2 receptor (PLA2R) is detected in approximately 70% of biopsies of "primary" membranous nephropathy (MN). Crescents in MN in nonlupus patients suggest additional injury, such as antineutrophil cytoplasmic antibody (ANCA) or anti-glomerular basement membrane (anti-GBM)-associated glomerulonephritis and are postulated to reflect injury by a mechanism that unmasks cryptic epitopes leading to the second autoantibody. Methods: We studied PLA2R staining in nonlupus patients with MN and crescents. Native renal biopsies in 16 nonlupus patients with MN and crescents were stained for PLA2R. Results: The patients included 5 women and 11 men, with mean age 61 years and elevated serum creatinine (mean 4.68 mg/dL). Hematuria and proteinuria (mean 4.97 g/day) were documented in 13 patients. Two patients had positive serum anti-GBM antibody. Nine of 11 patients tested for ANCA were positive, with p-ANCA (n = 4), c-ANCA (n = 2), or both (n = 1), with 2 not specified. On average, 27% of glomeruli had crescents. One patient had an initial biopsy with MN, 4 years later had MN with crescent, and 7 years later had rebiopsy with persistent MN with crescents. One patient had ANCA-associated vasculitis, and 5 years later had MN and crescent. The remaining 14 patients had concurrent diagnoses of MN and crescents. PLA2R was positive in 5 cases, 3 with ANCA positivity, 2 with unknown ANCA status, and none with anti-GBM disease. The patient with initial MN preceding crescent was PLA2R positive; the patient with initial ANCA-associated vasculitis preceding MN was PLA2R negative. Conclusions: Most patients (64%) presented with concomitant MN and crescents, with rare occurrence of an initial disease process followed later by the second injury. PLA2R was positive in 31% of patients, suggesting most are secondary MN. Further study to determine the cryptic epitopes may shed light on the triggering mechanisms for these rare but unlikely coincidental glomerular injuries.

20.
Biochemistry ; 60(45): 3347-3361, 2021 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-34730336

RESUMO

Ribosomally synthesized post-translationally modified peptides (RiPPs) are ubiquitous and represent a structurally diverse class of natural products. The ribosomally encoded precursor polypeptides are often extensively modified post-translationally by enzymes that are encoded by coclustered genes. Radical S-adenosyl-l-methionine (SAM) enzymes catalyze numerous chemically challenging transformations. In RiPP biosynthetic pathways, these transformations include the formation of C-H, C-C, C-S, and C-O linkages. In this paper, we show that the Geobacter lovleyi sbtM gene encodes a radical SAM protein, SbtM, which catalyzes the cyclization of a Cys/SeCys residue in a minimal peptide substrate. Biochemical studies of this transformation support a mechanism involving H-atom abstraction at the C-3 of the substrate Cys to initiate the chemistry. Several possible cyclization products were considered. The collective biochemical, spectroscopic, mass spectral, and computational observations point to a thiooxazole as the product of the SbtM-catalyzed modification. To our knowledge, this is the first example of a radical SAM enzyme that catalyzes a transformation involving a SeCys-containing peptide and represents a new paradigm for formation of oxazole-containing RiPP natural products.


Assuntos
Peptídeos Antimicrobianos/metabolismo , Geobacter/metabolismo , S-Adenosilmetionina/química , Peptídeos Catiônicos Antimicrobianos/metabolismo , Peptídeos Catiônicos Antimicrobianos/fisiologia , Peptídeos Antimicrobianos/fisiologia , Produtos Biológicos/metabolismo , Catálise , Geobacter/patogenicidade , Espectrometria de Massas/métodos , Oxazóis , Processamento de Proteína Pós-Traducional/fisiologia , Proteômica/métodos , Ribossomos , S-Adenosilmetionina/metabolismo
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