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.

Temporal Changes in Serum S100B Levels From Prehospital to Early In-Hospital Sampling in Patients Suffering Traumatic Brain Injury.

Background: The biomarker S100B is used for the rule-out of intracranial lesions in patients with mild traumatic brain injury (TBI) and is suggested for prehospital use in Europe. Early kinetics of S100B are not exhaustively investigated in human TBI. This post hoc descriptive study of the data from the PreTBI studies aimed to characterize the early temporal changes of S100B using two-sample timepoints. Materials and Methods: Two consecutive blood samples were taken prehospital and in-hospital after injury and assayed for S100B. The endpoint adjudication of the outcome intracranial lesion was done by the evaluation of electronic medical patient journals. The data were analyzed using descriptive statistics, scatterplots, and temporal changes estimated by the locally weighted scatterplot smoothing (LOWESS) regression line. Results: A total of 592 adult patients with TBI were included; 566 with Glasgow Coma Scale (GCS) 14-15, 20 with GCS 9-13, and 6 with GCS 3-8. Intracranial lesions were diagnosed in 44/566 (7.4%) of patients. In 90% of patients, S100B concentrations decreased from prehospital to in-hospital sampling. The mean decrease was-0.34 µg/L. S100B concentrations seem to decline already within 60 min. Patients sampled very close to trauma and patients suffering intracranial lesions may express a slight incline before this decline. Temporal changes of S100B did not differ in patients >65 years of age, in antiplatelet/-coagulant treatment, alcohol intoxicated, or suffering extra-cranial injuries. Conclusion: S100B concentrations may peak earlier than expected from previous studies of temporal changes in human TBI. Patterns of S100B stand robust to parameters stated as limiting factors to the use for early rule-out of intracranial lesions in the current guidelines. Further studies are needed to investigate the ultra-early temporal profiles of other novel TBI biomarkers to assess prehospital applicability and optimal diagnostic performance in TBI.

Temporal Release of High-Sensitivity Cardiac Troponin T and I and Copeptin After Brief Induced Coronary Artery Balloon Occlusion in Humans.

BACKGROUND: Cardiac troponins (cTns) are the cornerstone of diagnosing acute myocardial infarction. There is limited knowledge on the duration of ischemia necessary to induce a measurable release of cTns or the very-early-release kinetics of cTns after an ischemic event. Copeptin may have a supplementary role in ruling out myocardial infarction early. We investigated the release of cTns and copeptin in the first hours after experimental balloon-induced ischemia in humans. METHODS: Thirty-four patients (median age, 60 years [interquartile range, 51-64]; 15 men, 43%) with angiographically normal coronary arteries were randomly assigned into 4 groups with different durations of induced myocardial ischemia (0, 30, 60, 90 s). Ischemia was induced by inflating a balloon in the left anterior descending artery between the first and second diagonal branch. Blood was collected before balloon inflation (baseline) every 15 minutes for the first 3 hours, and every 30 minutes for the next 3 hours. The cTns were analyzed by 3 high-sensitivity (hs) cTn assays: hs-cTnT (Roche), hs-cTnI (Siemens), and hs-cTnI (Abbott). Copeptin was analyzed by a sandwich immunoluminometric assay. RESULTS: None of the patients had any complications. Increased cTn concentrations were detected by all 3 assays, and the magnitude of the increase was associated with the duration of ischemia. Increased hs-cTnI (Siemens) concentrations were first detectable 15 minutes after 90-s ischemia (median 43.7% increase) and increased more steeply and had a higher peak than the other assays. Copeptin levels did not significantly change. Using the cTnT, hs-cTnI (Siemens), and hs-cTnI (Abbott) concentrations at 0 and 180 minutes, 1 (11%), 0, and 0 patients from the 60-s ischemia group and 5 (63%), 2 (25%), and 1 (11%) from the 90-s ischemia group, respectively, fulfilled criteria for a biochemical myocardial infarction. CONCLUSIONS: This study is the first to report the early-release kinetics of cTn concentrations after different durations of experimental coronary balloon occlusion in humans. All assays detected a cTn increase after only 30 s of ischemia. hs-cTnI (Siemens) rose faster and reached a higher peak. Copeptin levels did not change significantly. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03203057.

Bilateral adrenal gland hemorrhage in a patient treated with rivaroxaban.

This is the report of a case of a 63-year-old woman, with a history of recurrent deep vein thrombosis, who was admitted with abdominal pain and diagnosed with bilateral adrenal hemorrhage, resulting in acute adrenal insufficiency. Several risk factors for adrenal hemorrhage were present: stress because of infection, treatment with the factor Xa-inhibitor rivaroxaban and the presence of antiphospholipid antibodies. Venous thrombosis of the adrenal glands with subsequent hemorrhagic infarction is a possible mechanism. It is currently unclear if patients with antiphospholipid syndrome can be treated effectively and safely with a nonvitamin K-antagonist oral anticoagulant.

Venous thromboembolism and subsequent risk of cancer in patients with liver disease: a population-based cohort study.

OBJECTIVE: Venous thromboembolism (VTE) may be a marker of occult cancer in the general population. While liver disease is known to increase the risk of VTE and cancer, it is unclear whether VTE in patients with liver disease is also a marker of occult cancer. DESIGN: A population-based cohort study. SETTING: Denmark. PARTICIPANTS: We used population-based health registries to identify all patients with liver disease in Denmark with a first-time diagnosis of VTE (including superficial or deep venous thrombosis and pulmonary embolism) during 1980-2010. Patients with non-cirrhotic liver disease and patients with liver cirrhosis were followed as two separate cohorts from the date of their VTE. MEASURES: For each cohort, we computed the absolute and relative risk (standardised incidence ratio; SIR) of cancer after VTE. RESULTS: During the study period, 1867 patients with non-cirrhotic liver disease and 888 with liver cirrhosis were diagnosed with incident VTE. In the first year following VTE, the absolute risk of cancer was 2.7% among patients with non-cirrhotic liver disease and 4.3% among those with liver cirrhosis. The SIR for the first 90 days of follow-up was 9.96 (95% CI 6.85 to 13.99) among patients with non-cirrhotic liver disease and 13.11 (95% CI 8.31 to 19.67) among patients with liver cirrhosis. After 1 year of follow-up, SIRs declined, but remained elevated in patients with non-cirrhotic liver disease (SIR=1.50, 95% CI 1.23 to 1.81) and patients with liver cirrhosis (SIR=1.95, 95% CI 1.45 to 2.57). CONCLUSIONS: VTE may be a marker of occult cancer in patients with liver disease.