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Biomedical subjects

T Zielinski

Publications and source records attributed to T Zielinski.

23 records · Page 2Linked to original sources
PubMed1993

Influence of isosorbide dinitrate (ISDN) on compliance of the pulmonary venous system.

Irreversible poor pulmonary venous compliance can worsen the natural course of patients with high pulmonary capillary wedge pressure, especially those with mitral stenosis, but nitrates (isosorbide dinitrate--ISDN), which have venodilatory properties, could increase this compliance in most patients. The aim of this study was to assess the hemodynamic effects of ISDN in patients with mitral stenosis, with special emphasis on the pulmonary venous compliance. Pulmonary venous compliance was estimated according to the Hirakawa equation (dV/dp = 0.4 x k2 x sV/(v-d)) in 39 patients with mitral stenosis during preoperative right heart catheterization with Vygon 5155-180 thermodilution catheters at rest and during exercise (25 W) in the supine position. This procedure was repeated after the application of 3.75 mg of Iso-Mack spray. Overall, ISDN increased pulmonary venous compliance significantly both at rest and during exercise (6.0 to 7.5 ml/mmHg and 6.0 to 7.6 ml/mmHg, respectively). The patients were divided into two groups according to their level of ISDN response; those with a good response of an increase of 15% or more in pulmonary venous compliance (Group I), and those with an increase of less than 15% (Group II). There were significant differences between these two groups in stroke volume index and heart rate. In Group I, while the mean right atrial pressure, mean pulmonary artery pressure and mean pulmonary wedge pressure all decreased significantly, there was a simultaneous insignificant decrease in the stroke volume index and an also insignificant increase in the heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Function, Right↗
PubMed1991

Leflunomide (HWA 486), a novel immunomodulating compound for the treatment of autoimmune disorders and reactions leading to transplantation rejection.

Leflunomide has been shown to be very effective in preventing and curing several autoimmune animal diseases. Further, this agent is as effective as cyclosporin A in preventing the rejection of skin and kidney transplants in rats. Preliminary results from patients suffering from severe cases of rheumatoid arthritis demonstrated that clinical and immunological parameters could be improved with leflunomide therapy. Mode of action studies revealed that this substance antagonizes the proliferation inducing activity of several cytokines and is cytostatic for certain cell types. In this light, we could show that tyrosine phosphorylation of the RR-SRC peptide substrate and the autophosphorylation of the epidermal growth factor (EGF) receptor were, dose dependently, inhibited by leflunomide. EGF activates the intrinsic tyrosine kinase of its receptor, which stimulates the phosphorylation of a variety of peptides, the amino acid residue in all cases is tyrosine. These results indicate that much of leflunomide's activity could be due to the inhibition of tyrosine-kinase(s), which is an important general mechanism for the proliferation of various cell types. Thus, leflunomide, which is effective against autoimmune diseases and reactions leading to graft rejection, would seem to have a mode of action separating it from known immunosuppressive drugs.

Amino Acid Sequence↗
PubMed1989

The diabetic heart: a porcine model evaluated with positron emission tomography using 1-11C-palmitate and 3-11C-pyruvate.

The potential value of positron emission tomography (PET) in evaluating the myocardial energy metabolism was studied in two previously healthy mini-pigs before, during and after the induction of non-insulin dependent diabetes with alloxan. The distribution and kinetics of radioactivity derived from trace amounts of 11C-pyruvate and 1-11C-palmitate were followed in different sections of the myocardium. The early distribution of both tracers was similar even after the development of diabetes. The elimination of 11C-pyruvate derived radioactivity was slower in the diabetic heart. The rate of beta-oxidation was also decreased as suggested by the elimination curve of 11C-palmitate and the incorporation of 11C-palmitate into the triglyceride and phospholipid pool of the myocardium was increased in the diabetic animals. The results are consistent with previous observations using other techniques. Positron emission tomography offers the opportunity to characterize regional tissue metabolism quantitatively in vivo. This method may become a powerful tool in studying myocardial metabolism and the metabolic basis for the cardiac dysfunction in diabetes mellitus.

Animals↗