Circulating Cardiac Troponin-I Autoantibodies in Human Plasma and Serum
ABSTRACT We identified IgG reactive with human cardiac troponin-I (cTnI) in plasma and serum samples (N = 1930) from normal blood donors, and in sample cohorts characterized on the basis of clinical biomarkers associated with cardiac, infectious, and autoimmune diseases. cTnI and brain natriuretic peptide were the biomarkers chosen to reflect myocyte damage or left ventricular dysfunction, respectively. The infectious disease cohorts were serologically positive for antibodies to hepatitis B (natural infection), hepatitis C virus, and Chagas (i.e., T.cruzi). The autoimmune cohorts were represented by samples from diagnosed systemic lupus erythematosus (biomarker: dsDNA) and rheumatoid arthritis (biomarker: rheumatoid factor) subjects. The prevalence of IgG autoantibodies reactive with cTnI was high in the normal donor cohort (95/750, 12.7%). The prevalence in the other sample cohorts was not significantly different from that in the normal blood donors, with the exception of a slight increase in the rheumatoid factor cohort (28/137, 20.4%). The presence of anti-cTnI IgG in highly reactive samples was confirmed by inhibition with the antigen and further by screening with a library of peptides derived from the human cTnI amino acid sequence. Our data suggest that these autoantibodies are polyspecific, encompassing epitopes across the entire cTnI sequence, including the cardiac-specific amino terminal region.
- [Show abstract] [Hide abstract]
ABSTRACT: The resilient guaranteed cost control (RGCC) problem is studied in this paper for a class of uncertain singular systems with a given quadratic cost function. The uncertainty in the system is assumed to be norm-bounded and time-varying. The problem is to design a state feedback control law such that the closed-loop systems are regular, stable, and impulse-free, while the cost index of the closed-loop systems is within a certain bound for all these admissible uncertainties. Sufficient conditions for the existence of resilient guaranteed cost controller are given by Riccati equalities. The design of the resilient guaranteed cost controller and the corresponding guaranteed cost of the systems are obtained. Finally, a numerical example is given to illustrate the design method.Intelligent Control and Automation, 2004. WCICA 2004. Fifth World Congress on; 07/2004
- Clinical Chemistry 04/2010; 56(4):676-7. DOI:10.1373/clinchem.2009.138099 · 7.77 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: CASE A 69-year-old man with diabetes mellitus type II, hy- pertension, dyslipidemia, and prior ischemic strokes presented to the emergency department with com- plaints of balance difficulties and inability to stand un- assisted of 2 weeks' duration. The patient's home medication regimen included atenolol, lisinopril, am- lodipine, metformin, and glipizide. He is a retired chef and a former smoker (20 pack-years). He has 2 broth- ers, both of whom had myocardial infarctions in their 50s. The patient's physical examination was remark- ableforfrequentprematurecontractions,leftlowerex- tremity weakness, and impaired coordination. His electrocardiogram revealed sinus rhythm with fre- quent premature ventricular contractions and diffuse nonspecific T-wave abnormalities. Results of a comprehensive metabolic chemistry panel were within the reference intervals except for in- creases in glucose (158 mg/dL; reference interval, 74-99mg/dL)andcreatinine(1.5mg/dL;referencein- terval, 0.7-1.3 mg/dL). The hemoglobin A1c value was 7.4% (reference interval, 6.0%). Cardiac troponin IClinical Chemistry 05/2010; 56(5):702-5. DOI:10.1373/clinchem.2009.138164 · 7.77 Impact Factor