Validation of a fibrinogen γ’ enzyme-linked immunosorbent assay using a new monoclonal antibody:effects of bariatric surgery

Background: Fibrinogen γ’ is a naturally occurring 20-amino-acid splice variant of the fibrinogen γ chain. Animal studies link variations in fibrinogen to obesity, but it is unknown how fibrinogen γ’ is associated with obesity in humans. Objectives: To develop and validate an enzyme-linked immunosorbent assay (ELISA) for fibrinogen γ’ quantification in human plasma and analyze fibrinogen γ’ before and after bariatric surgery. Methods: We generated C-terminal fibrinogen γ’ specific mouse monoclonal antibodies and developed a γ’ ELISA. Validation included measures of accuracy, sensitivity, and precision. Fibrinogen γ’ and total fibrinogen were measured in 60 individuals before and 6 months after bariatric surgery and in 19 normal-weight controls and 120 blood donors. Results: Highly specific fibrinogen γ’ monoclonal antibodies were produced and successfully used in the ELISA. Recovery was 88%, and limits of detection and quantification were 0.003 mg/mL and 0.014 mg/mL, respectively. Coefficients of variation were 3% for repeatability and 7% for within-laboratory variation. The fibrinogen γ’ reference interval was 0.25 to 0.80 mg/mL. Fibrinogen γ’ concentrations were reduced after bariatric surgery and were higher in individuals with obesity than in those with normal weight. The fibrinogen γ’/total fibrinogen ratio was unchanged after surgery but was higher than the ratio in normal-weight individuals. Conclusion: We developed a precise and sensitive ELISA for fibrinogen γ’. Levels of fibrinogen γ’, but not the fibrinogen γ’/fibrinogen ratio, were reduced 6 months after bariatric surgery. Absolute and relative levels of fibrinogen γ’ were increased in individuals with obesity compared to normal-weight individuals.</p

Validation of a fibrinogen γ’ enzyme-linked immunosorbent assay using a new monoclonal antibody:effects of bariatric surgery

Background: Fibrinogen γ’ is a naturally occurring 20-amino-acid splice variant of the fibrinogen γ chain. Animal studies link variations in fibrinogen to obesity, but it is unknown how fibrinogen γ’ is associated with obesity in humans. Objectives: To develop and validate an enzyme-linked immunosorbent assay (ELISA) for fibrinogen γ’ quantification in human plasma and analyze fibrinogen γ’ before and after bariatric surgery. Methods: We generated C-terminal fibrinogen γ’ specific mouse monoclonal antibodies and developed a γ’ ELISA. Validation included measures of accuracy, sensitivity, and precision. Fibrinogen γ’ and total fibrinogen were measured in 60 individuals before and 6 months after bariatric surgery and in 19 normal-weight controls and 120 blood donors. Results: Highly specific fibrinogen γ’ monoclonal antibodies were produced and successfully used in the ELISA. Recovery was 88%, and limits of detection and quantification were 0.003 mg/mL and 0.014 mg/mL, respectively. Coefficients of variation were 3% for repeatability and 7% for within-laboratory variation. The fibrinogen γ’ reference interval was 0.25 to 0.80 mg/mL. Fibrinogen γ’ concentrations were reduced after bariatric surgery and were higher in individuals with obesity than in those with normal weight. The fibrinogen γ’/total fibrinogen ratio was unchanged after surgery but was higher than the ratio in normal-weight individuals. Conclusion: We developed a precise and sensitive ELISA for fibrinogen γ’. Levels of fibrinogen γ’, but not the fibrinogen γ’/fibrinogen ratio, were reduced 6 months after bariatric surgery. Absolute and relative levels of fibrinogen γ’ were increased in individuals with obesity compared to normal-weight individuals.</p

Effect of bariatric surgery on employment status—a 7 years controlled nationwide registry study

Background Severe obesity is associated with a reduced ability to work. Bariatric surgery is the most effective method to achieve a sustained weight loss. Previous studies have reported conflicting results regarding the effect of bariatric surgery on employment status. To address this, we investigated the effect of bariatric surgery on employment status in the Danish population.Methods In this nationwide study, we identified 5450 subjects who underwent bariatric surgery and 10 900 control subjects matched for age, sex and municipality. From accessible registries, we extracted data regarding employment, absenteeism, sick leave and pension. Using a multistate model, we compared time in occupational states and transitions between these states to determine the effect of bariatric surgery on employment status.Findings Before surgery, cases had an absolute risk increase (95% CI)(ARI (CI)) and a relative risk (RR (CI)) of being in full-time employment of −0.12 (−0.14 to −0.10) and 0.84 (0.82 to 0.86) and were more often unemployed or in a subsidised job than the background population. Taking into account the employment status before surgery, the bariatric surgery group increased their probability of being in full-time employment 1–3 years after bariatric surgery. However, this positive effect was not present with a longer duration of follow-up. Being male, above 50 years of age, or employed as a craftsman or office worker were associated with a sustained positive effect of being in full-time employment (ARI (CI) and RR (CI) 0.05 (0.04 to 0.05) and 1.05 (1.04 to 1.06), 0.06 (0.06 to 0.07) and 1.08 (1.07 to 1.09) and 0.05 (0.05 to 0.06) and 1.05 (1.05 to 1.06), respectively).Interpretation Compared with a matched control group, those undergoing bariatric surgery did not improve their employment status in the long term. Certain subgroups had a more sustained positive effect

Efficacy and safety of left bundle branch area pacing versus right ventricular apex pacing in patients with atrioventricular block: study protocol for a randomised controlled trial

Introduction Left bundle branch area pacing (LBBaP) is a relatively new approach for physiologic pacing. A limited number of retrospective clinical studies, featuring small sample sizes, have shown that compared with right ventricular apex pacing (RVAP), the QRS duration of postoperative ECG in LBBaP patients is narrower and the cardiac systolic function is improved. However, there have been no randomised controlled trials (RCTs) evaluating the efficacy and safety of LBBaP in patients with atrioventricular block (AVB). Therefore, the current study intends to address the paucity in RCT data evaluating LBBaP versus RVAP in AVB patients.Analysis and methods This study is a single-centre, randomised controlled superiority trial to be conducted at the Cardiac Centre of Beijing Anzhen Hospital. From January 2021 to December 2023, 210 consecutive AVB patients meeting the inclusion criteria and receiving pacemaker implantation will be enrolled. Participants will be randomly divided into an experimental group (LBBaP) and a control group (RVAP) at a 1:1 ratio. The primary outcome is left ventricular ejection fraction (LVEF), which will be assessed by echocardiography. The secondary outcomes in this study are synchrony of left ventricular systole, NT-proBNP, LVEDD, the 6-min walk distance, quality of life (SF-36 scale), all-cause mortality, cardiovascular death events, rehospitalisation rate and major complication rate.Ethics and dissemination This study was approved by the Medical Ethics Committee of Beijing Anzhen Hospital (No. 2020021X). The results of the trial will be presented at national and international conferences. We hypothesise that compared with RVAP, LBBaP will be superior for treating patients with AVB. This trial will provide evidence-based suggestion for the majority of electrophysiologists in pacing implantation.Trial registration ChiCTR2000034335

Additional file 1 of Zoledronic Acid for prevention of bone and muscle loss after BAriatric Surgery (ZABAS)-a study protocol for a randomized controlled trial

Additional file 1. SPIRIT 2013 Checklist