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result(s) for
"factor-antigen-i"
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Colonization factors among enterotoxigenic Escherichia coli isolates from children with moderate-to-severe diarrhea and from matched controls in the Global Enteric Multicenter Study (GEMS)
by
Ahmed, Shahnawaz
,
Adegbola, Richard
,
Del Canto, Felipe
in
Africa - epidemiology
,
Analysis
,
Antigens
2019
Enterotoxigenic Escherichia coli (ETEC) encoding heat-stable enterotoxin (ST) alone or with heat-labile enterotoxin (LT) cause moderate-to-severe diarrhea (MSD) in developing country children. The Global Enteric Multicenter Study (GEMS) identified ETEC encoding ST among the top four enteropathogens. Since the GEMS objective was to provide evidence to guide development and implementation of enteric vaccines and other interventions to diminish diarrheal disease morbidity and mortality, we examined colonization factor (CF) prevalence among ETEC isolates from children age <5 years with MSD and from matched controls in four African and three Asian sites. We also assessed strength of association of specific CFs with MSD.
MSD cases enrolled at healthcare facilities over three years and matched controls were tested in a standardized manner for many enteropathogens. To identify ETEC, three E. coli colonies per child were tested by polymerase chain reaction (PCR) to detect genes encoding LT, ST; confirmed ETEC were examined by PCR for major CFs (Colonization Factor Antigen I [CFA/I] or Coli Surface [CS] antigens CS1-CS6) and minor CFs (CS7, CS12, CS13, CS14, CS17, CS18, CS19, CS20, CS21, CS30). ETEC from 806 cases had a single toxin/CF profile in three tested strains per child. Major CFs, components of multiple ETEC vaccine candidates, were detected in 66.0% of LT/ST and ST-only cases and were associated with MSD versus matched controls by conditional logistic regression (p≤0.006); major CFs detected in only 25.0% of LT-only cases weren't associated with MSD. ETEC encoding exclusively CS14, identified among 19.9% of 291 ST-only and 1.5% of 259 LT/ST strains, were associated with MSD (p = 0.0011). No other minor CF exhibited prevalence ≥5% and significant association with MSD.
Major CF-based efficacious ETEC vaccines could potentially prevent up to 66% of pediatric MSD cases due to ST-encoding ETEC in developing countries; adding CS14 extends coverage to ~77%.
Journal Article
Cross-reactivity and avidity of antibody responses induced in humans by the oral inactivated multivalent enterotoxigenic Escherichia coli (ETEC) vaccine ETVAX
2017
Highlights • ETVAX induces cross-reactive antibodies that bind to related, non-vaccine colonisation factors. • ETVAX may protect against a wider range of ETEC strains than previously appreciated. • A novel approach to determine antibody avidity based on limiting antigen dilution is described. • Repeat ETVAX vaccination induces vaccine-specific antibodies with increased avidity.
Journal Article
The von Willebrand Factor antigen to platelet ratio (VITRO) score predicts hepatic decompensation and mortality in cirrhosis
2020
BackgroundThe ratio of von Willebrand Factor to platelets (VITRO) reflects the severity of fibrosis and portal hypertension and might thus hold prognostic value.MethodsPatients with compensated cirrhosis were recruited. VITRO, Child–Pugh score (CPS) and MELD were determined at study entry. Hepatic decompensation was defined as variceal bleeding, ascites or hepatic encephalopathy. Liver transplantation and death were recorded.ResultsOne hundred and ninety-four patients with compensated cirrhosis (CPS-A 89%, B 11%; 56% male; median age 56 years; 50% with varices) were included. During a median follow-up of 45 months (IQR 29–61), decompensation occurred in 35 (18%) patients and 14 (7%) patients deceased. The risk of hepatic decompensation was significantly increased in the n = 88 (45%) patients with a VITRO ≥ 2.5 (p < 0.001). Patients with a VITRO ≥ 2.5 had a higher probability of decompensation at 1-year 9% (95% CI 3–16) vs. 0% (95% CI 0–0) and at 2-years 18% (95% CI 10–27%), vs. 4% (95% CI 0–8%) as compared to patients with VITRO < 2.5. Patients with VITRO ≥ 2.5, the estimated 1-year/2-year survival rates were at 98% (95% CI 95–100%) and 94% (95% CI 88–99%) as compared to 100% (95% CI 100–100%) both in the patients with a VITRO < 2.5 (p < 0.001). After adjusting for age, albumin and MELD, VITRO ≥ 2.5 remained as significant predictor of transplant-free mortality (HR 1.38, CI 1.09–1.76; p = 0.007). Patients with compensated cirrhosis and VITRO > 2.1 after hepatitis C eradication remained at significantly increased risk for decompensation (p = 0.033).ConclusionsVITRO is a valuable prognostic tool for estimating the risk of decompensation and mortality in patients with compensated cirrhosis—including the setting after hepatitis C eradication.
Journal Article
Vascular Dysfunction in Patients With Young β-Thalassemia
We aimed to study the endothelial dysfunction among children and adolescents with transfusion-dependent β-thalassemia using von Willebrand factor antigen (VWF:Ag) and flow cytometric analysis of circulating CD144+ endothelial microparticles (EMPs) and endothelial progenitor cells (CD34+VEGFR2+) and assess their relation to iron overload, erythropoietin and chelation therapy as well as echocardiographic parameters and carotid intima–media thickness. The VWF:Ag, EMPs, and CD34+VEGFR2+ cells were significantly higher among patients with β-thalassemia than controls (P < .001). The type of chelation and patients’ compliance did not influence the results. No significant correlations were found between the studied vascular markers. Patients with evident heart disease had higher VWF: Ag, EMPs, and CD34+VEGFR2+ cells than those without. Carotid intima–media thickness was increased among patients but not correlated with vascular markers. We suggest that procoagulant EMPs and VWF: Ag are involved in cardiovascular complications in patients with young β-thalassemia. CD34+VEGFR2+ cells were further increased in response to tissue injury contributing to reendothelialization and neovascularization.
Journal Article
The von Willebrand Factor Antigen Reflects the Juvenile Dermatomyositis Disease Activity Score
2023
Objective: This study determined if an accessible, serologic indicator of vascular disease activity, the von Willebrand factor antigen (vWF:Ag), was useful to assess disease activity in children with juvenile dermatomyositis (JDM), a rare disease, but the most common of the pediatric inflammatory myopathies. Methods: A total of 305 children, median age 10 years, 72.5% female, 76.5% white, with definite/probable JDM at diagnosis, were enrolled in the Ann & Robert H. Lurie Cure JM Juvenile Myositis Repository, a longitudinal database. Disease Activity Score (DAS) and vWF:Ag data were obtained at each visit. These data were analyzed using generalized estimating equation (GEE) models (both linear and logistic) to determine if vWF:Ag reflects disease severity in children with JDM. A secondary analysis was performed for untreated active JDM to exclude the effect of medications on vWF:Ag. Result: The vWF:Ag test was elevated in 25% of untreated JDM. We found that patients with elevated vWF:Ag had a 2.55-fold higher DAS total (CI95: 1.83–3.27, p < 0.001). Patients with difficulty swallowing had 2.57 higher odds of elevated vWF:Ag (CI95: 1.5–4.38, p < 0.001); those with more generalized skin involvement had 2.58-fold higher odds of elevated vWF:Ag (CI95: 1.27–5.23, p = 0.006); and those with eyelid peripheral blood vessel dilation had 1.32-fold higher odds of elevated vWF:Ag (CI95: 1.01–1.72, p = 0.036). Untreated JDM with elevated vWF:Ag had more muscle weakness and higher muscle enzymes, neopterin and erythrocyte sedimentation rate compared to JDM patients with a normal vWF:Ag. Conclusion: vWF:Ag elevation is a widely accessible concomitant of active disease in 25% of JDM.
Journal Article
Von Willebrand Factor Antigen, Biomarkers of Inflammation, and Microvascular Flap Thrombosis in Reconstructive Surgery
by
Citovica, Margarita
,
Gravelsina, Sabine
,
Bine, Evita
in
Analysis
,
Antigens
,
Biological markers
2024
Background: Microvascular flap surgery has become a routine option for defect correction. The role of von Willebrand factor antigen (VWF:Ag) in the pathophysiology of flap complications is not fully understood. We aim to investigate the predictive value of VWF:Ag for microvascular flap complications and explore the relationship between chronic inflammation and VWF:Ag. Methods: This prospective cohort study included 88 adult patients undergoing elective microvascular flap surgery. Preoperative blood draws were collected on the day of surgery before initiation of crystalloids. The plasma concentration of VWF:Ag as well as albumin, neutrophil-to-lymphocyte ratio (NLR), interleukin-6, and fibrinogen were determined. Results: The overall complication rate was 27.3%, and true flap loss occurred in 11.4%. VWF:Ag levels were higher in true flap loss when compared to patients without complications (217.94 IU/dL [137.27–298.45] vs. 114.14 [95.67–132.71], p = 0.001). Regression analysis revealed the association between VWF:Ag and true flap loss at the cutoff of 163.73 IU/dL (OR 70.22 [10.74–485.28], p = 0.043). Increased VWF:Ag concentrations were linked to increases in plasma fibrinogen (p < 0.001), C-reactive protein (p < 0.001), interleukin-6 (p = 0.032), and NLR (p = 0.019). Conclusions: Preoperative plasma VWF:Ag concentration is linked to biomarkers of inflammation and may be valuable in predicting complications in microvascular flap surgery.
Journal Article
von Willebrand Factor Assay Proficiency Testing
by
Peerschke, Ellinor I.B.
,
Castellone, Donna D.
,
Meijer, Piet
in
Biological and medical sciences
,
Blood Coagulation Tests - standards
,
Hematologic and hematopoietic diseases
2011
We evaluated the accuracy and precision of von Willebrand disease (vWD) testing performed by up to 50 North American Specialty Coagulation Laboratories from 2004 through 2009, using proficiency samples from healthy subjects (n = 7) and patients with type 1 vWD (n = 7) or type 2 vWD (n = 3). We analyzed 2,212 submitted results. Precision was highest for von Willebrand factor (vWF) antigen assays (coefficient of variation, 14%), which were performed predominantly by latex immunoassays, and lowest for ristocetin cofactor assays (coefficient of variation, 28%), which were increasingly replaced by collagen binding and immunofunctional methods during the 6-year evaluation period. Overall interpretation error rates ranged from 3% for normal samples, 28% for type 1 vWD, and 60% for type 2 vWD. Type 2 vWD samples were correctly identified by all laboratories using collagen binding/antigen ratios but by only one third of laboratories using ristocetin cofactor/antigen or immunofunctional/antigen ratios. In 2009, only 27% (12/45) of laboratories performed vWF multimer analysis, with error rates ranging from 7% to 22%.
Journal Article
Circulating cardiovascular risk factors in obstructive sleep apnoea: data from randomised controlled trials
by
Segal, H C
,
Robinson, G V
,
Pepperell, J C T
in
Adult
,
Aged
,
Atherosclerosis (general aspects, experimental research)
2004
Background: Obstructive sleep apnoea (OSA) is associated with high cardiovascular morbidity and mortality and is an independent risk factor for hypertension. Novel circulating cardiovascular risk markers enabling a more accurate prediction of cardiovascular risk have been identified. Examination of these markers may clarify the increased risk in OSA and contribute to an analysis of the benefits of treatment. Methods: Plasma levels of total cholesterol and triglyceride and activated coagulation factors XIIa and VIIa, factors VII, VIII, XII, fibrinogen, thrombin-antithrombin (TAT), von Willebrand factor antigen (vWFAg), soluble P-selectin (sP-sel), and homocysteine were measured before and after treatment for 1 month with therapeutic or subtherapeutic (control) continuous positive airways pressure (CPAP) in 220 patients with OSA. Results: Levels of activated coagulation factors XIIa, VIIa, TAT and sP-sel were higher in OSA patients at baseline than in unmatched controls, but did not fall with 1 month of therapeutic CPAP treatment. The raised sP-sel levels correlated only with body mass index (p = 0.002). There was a trend towards a significant fall in total cholesterol with therapeutic CPAP (p = 0.06) compared with the control group. In the therapeutic group there was a clinically significant mean fall in total cholesterol of 0.28 mmol/l (95% confidence interval 0.11 to 0.45, p = 0.001) which may reduce cardiovascular risk by about 15%. Conclusion: A number of activated coagulation factors are increased in untreated OSA patients, potentially contributing to vascular risk, but they do not fall with 1 month of CPAP treatment. Nasal CPAP may produce a clinically relevant fall in total cholesterol level, potentially reducing cardiovascular risk, but this needs to be verified in a larger prospective study.
Journal Article
Glyco-engineered cell line and computational docking studies reveals enterotoxigenic Escherichia coli CFA/I fimbriae bind to Lewis a glycans
2018
We have previously reported clinical data to suggest that colonization factor I (CFA/I) fimbriae of enterotoxigenic
Escherichia coli
(ETEC) can bind to Lewis a (Le
a
), a glycan epitope ubiquitous in the small intestinal mucosa of young children (<2 years of age), and individuals with a genetic mutation of
FUT2
. To further elucidate the physiological binding properties of this interaction, we engineered Chinese Hamster Ovary (CHO-K1) cells to express Le
a
or Le
b
determinants on both
N
- and
O
-glycans. We used our glyco-engineered CHO-K1 cell lines to demonstrate that CfaB, the major subunit of ETEC CFA/I fimbriae, as well as four related ETEC fimbriae, bind more to our CHO-K1 cell-line expressing Le
a
, compared to cells carrying Le
b
or the CHO-K1 wild-type glycan phenotype. Furthermore, using
in-silico
docking analysis, we predict up to three amino acids (Glu
25
, Asn
27
, Thr
29
) found in the immunoglobulin (Ig)-like groove region of CfaB of CFA/I and related fimbriae, could be important for the preferential and higher affinity binding of CFA/I fimbriae to the potentially structurally flexible Le
a
glycan. These findings may lead to a better molecular understanding of ETEC pathogenesis, aiding in the development of vaccines and/or anti-infection therapeutics.
Journal Article
Evaluation of endothelial microparticles as a prognostic marker in hemolytic disease of the newborn in China
by
Zhang, Cong-min
,
Wei, Jin-kai
,
Zhu, Xiao-jing
in
ABO Blood-Group System - metabolism
,
Antigens, CD - metabolism
,
Biomarkers - metabolism
2019
Objective
This study aimed to evaluate endothelial microparticles (EMPs) as a potential prognostic marker in hemolytic disease of the Chinese neonate.
Methods
We compared 29 newborns with ABO hemolytic disease of the newborn (ABO HDN), 22 newborns with Rh HDN, and 21 healthy newborns with matched mother and infant blood groups (controls). Markers of hemolysis and von Willebrand factor antigen (vWF Ag) were analyzed. EMP (CD144+) levels were measured before and after therapy.
Results
vWF Ag and pretherapy EMP levels were higher in the ABO HDN and Rh HDN groups than in the control group. Additionally, vWF Ag and pretherapy EMP levels were significantly higher in the ABO HDN group than in the Rh HDN group. Posttherapy EMP levels were decreased compared with pretherapy levels in the ABO HDN and Rh HDN groups. Moreover, hemoglobin and indirect bilirubin levels were independently correlated with pretherapy EMP levels in the ABO HDN group.
Conclusion
Our findings indicate that EMP measurement in neonates with HDN may provide a novel method of monitoring possible severe vascular dysfunction in patients in China. An external validation in larger datasets is necessary for further study.
Journal Article