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Biomedical subjects

T H Peters

Publications and source records attributed to T H Peters.

5 recordsLinked to original sources
PubMed2001

Endocardial expression and functional characterization of endothelin-1.

Endothelin-1 (ET-1), a 21 amino acid peptide exerts a wide range of biological activities including vasoconstriction, mitogenesis and inotropic effects on the heart. In this study, we examined whether endocardial endothelial cells express ET-1 and evaluated its functional properties. Using immunofluorescence localization method, we demonstrated cytoplasmic staining of ET-1 in the human endocardial endothelial cells from the right atrium and left ventricle. Employing reverse transcriptase polymerase chain reaction (RT-PCR) expression of ET-1 mRNA and its receptors ET(A) and ET(B) mRNAs were found in human myocardial as well as in endocardial endothelial cells. Biological activity of endocardial endothelial cells derived ET-1 was established as the conditioned media obtained from cultured porcine endocardial endothelial cells induced a slowly developing, strong and long-lasting contraction of circular rat aortic segments, with similar characteristics to that obtained with exogenous ET-1. Furthermore, the selective endothelin-A receptor antagonist, FR 139317, blocked the conditioned media induced contractions. Our results suggest that endocardial endothelial cells express and release biologically active ET-1 which could play a pivotal role in the regulation of myocardial contractility as well as a circulatory peptide may further act in other peripheral target organs.

Animals↗
PubMed1999

Quantitative analysis of collagens and fibronectin expression in human right ventricular hypertrophy.

One of the main features in human tetralogy of Fallot (TF) is right ventricular hypertrophy (RVH) due to pressure (sub-pulmonary stenosis) and volume overload (ventricular septal defect). Currently, primary correction at a young age is the treatment of choice. To unravel the role of extracellular matrix in RVH, we examined myocardial expression of collagens and fibronectin in TF patients with primary correction (TF1, age 0.7 +/- 0.2 yr.), secondary surgery (TF2, age 36.9 +/- 4.6 yr), and in age-matched control patients. Sirius red staining quantified by video imaging showed significantly increased interstitial staining for collagens in both TF1 and TF2 groups as compared to respective controls. Fibronectin was expressed in extracellular spaces, perivascular regions, and in some cardiomyocytes. Quantitative analysis of fibronectin revealed increased expression in only TF1 group as compared to respective control. Our results indicate an increased amount of myocardial extracellular matrix deposition as a sign of fibrosis during RVH in patients with TF.

Adult↗
PubMed1996

Immunosuppressive therapy and hepatitis C virus infection: the clinical course of liver disease.

In a retrospective long-term follow-up study the clinical course of liver disease was examined in renal allograft recipients with hepatitis C virus (HCV) infection and negative hepatitis B surface antigen under immunosuppressive therapy. We compared 42 anti-HCV antibody (anti-HCV) positive patients (study group) to 213 anti-HCV negative patients (control group). All patients received immunosuppressive therapy. Measurements were made of the following: aminotransferases, bilirubin, albumin, gammaglobulins, ascites, spleen diameter, HCV RNA, and anti-HCV antibody. We found all but four anti-HCV positive patients to be HCV RNA positive prior to transplantation. There were no differences in overall mortality or mortality secondary to liver disease or sepsis. Normal liver enzymes were found in 13 (31%) anti-HCV positive and in 137 (64%) anti-HCV negative patients during the whole mean observation period of 65 months (range 10-215). Aminotransferase activity decreased in anti-HCV positive and negative patients during the observation period. Liver function with regard to synthesis and excretion was normal in anti-HCV negative and anti-HCV positive patients. No signs of portal hypertension were observed in the anti-HCV positive group. Neither the different immunosuppressive regimens nor the antirejection therapy led to differences between anti-HCV positive and negative groups with respect to liver function and did not alter the clinical course. We conclude that HCV infection in patients under immunosuppressive therapy causes only a mild liver disease, as determined by clinicochemical and clinical parameters, and that mortality rate is not increased.

Adolescent↗
PubMed1994

Laboratories in patient-centered units.

As part of a hospital pilot project evaluating decentralized patient-focused care, a new laboratory model was studied. Cross-trained personnel (nurses, medical technologists, radiology technologists, and respiratory therapists) performed high-volume, automated laboratory tests in a unit-based laboratory as part of their overall patient care duties. Testing performed in the patient-centered unit laboratory, in general, was comparable in quality to that reported by the hospital's central laboratory.

Academic Medical Centers↗