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Biomedical subjects

M Bednarek

Publications and source records attributed to M Bednarek.

23 records · Page 2Linked to original sources
PubMed1992

Conformational and ion binding properties of a cyclic octapeptide, cyclo (Ala-Leu-Pro-Gly)2.

The conformation and ion-binding characteristics of a cyclic octapeptide, cyclo (Ala-Leu-Pro-Gly)2, in a liphophilic solvent, acetonitrile, have been studied using CD and nmr spectroscopy. The peptide binds preferentially to divalent cations such as calcium, magnesium, and barium. The conformations of the free cyclic peptide and its calcium complex are very similar with well-defined beta- and gamma-turns. The cyclic peptide readily forms equimolar and possibly 2:1 (peptide:cation) complexes with divalent cations.

Amino Acid Sequence↗
PubMed1991

[Lovastatin in the treatment of primary hypercholesterolemia].

The results of 12 weeks treatment of primary hyperlipidemias with Lovastatin are presented. This drug belonging to a new generation of hypercholesterolemic drugs inhibits the endogenous synthesis of cholesterol by means of inhibiting the HMG-CoA reductase. The sample consisted of 30 men aged 28-68 years: in 17 of them heterozygotic familial hypercholesterolemia (FH) was diagnosed and in 13--primary non familial hypercholesterolemia (NFH). After 12 weeks of treatment in both groups a significant reduction of total serum cholesterol concentration was observed--(-28%) and--(-32%) as well as LDL-cholesterol concentration (in both groups about -37%) and apo B concentration--(-32%) and -34%. Only in one patients with NFH a significant reduction of VLDL-cholesterol (-29%) and or triglycerides (-15%) concentrations was observed. In this group also a 9% increase of HLD-cholesterol, mainly HDL-2 concentration, was found. Side effects were observed in 6 patients--in 4 of them a minor increase of ALAT, AsPAT or CPK activities (less than 3 times above norm were observed) without any symptoms and with a spontaneous normalization with no need to stop treatment, and in 2 of them abdominal pains not causing drug treatment cessation.

Adult↗
PubMed1990

Energetics of Ehrlich ascites mitochondria: membrane potential of isolated mitochondria and mitochondria within digitonin-permeabilized cells.

Ehrlich ascites tumour cells were treated with digitonin so that they became permeable for low-molecular-weight compounds but, at certain concentrations of digitonin, retained most of their cytoplasmic proteins. Respiration of mitochondria with exogenous substrates and their membrane potential could thus be measured in situ by means of oxygen electrode and tetraphenylphosphonium-sensitive electrode, respectively. The results were compared with data from similar measurements on mitochondria isolated from such digitonin-permeabilized cells. Isolated mitochondria and mitochondria in situ oxidized succinate at similar rates and developed membrane potential of comparable magnitude. Both preparations also exhibited an identical nonlinear relationship between resting state respiration (titrated with a respiratory inhibitor) and the membrane potential. In the cells permeabilized with low concentrations of digitonin (i.e., retaining most of cytoplasmic proteins) and suspended in medium containing NaCl and other major anions and cations at concentrations close to those in mammalian plasma, anaerobiosis did not produce a decrease in the mitochondrial membrane potential, which was collapsed only after a subsequent addition of oligomycin. In this medium, glucose had little effect on either respiration or the membrane potential.

Animals↗
PubMedDate not supplied

Effect of interferon alfa and ribavirin treatment on hepatitis C virus RNA in serum and peripheral blood mononuclear cells in children with chronic hepatitis C.

UNLABELLED: The correlations between the severity of hepatic lesions, age, gender, HBV co-infection and negativisation of HCV-RNA from serum and peripheral blood mononuclear cells (PBMC) after treatment of chronic hepatitis C (CHC) were analysed. 41 children (11 F/ 30 M), aged 5-16 years (mean 10 +/- 2.8), were treated with IFN-alpha and ribavirin for 12 months. Sustained negativisation of HCV-RNA from serum was achieved in 25 patients (61%), in 3 (7%) it reappeared after treatment, and in 13 (32%) it was ineffective. Clearance of HCV did not correlate with age (p = 0.65), sex (p = 0.13), past HBV infection (n = 22 anti-HBc +) (p = 0.24), maximum pre-treatment ALT activity (p = 0.06), grade of inflammation (p = 0.33) or stage of fibrosis (p = 0.9) in liver biopsy. It was achieved in 6/16 children previously resistant to IFN-a monotherapy and in 19/25 naive (p = 0.017). HCV-RNA was detected in PBMC in 9/24 (37%) seronegative children and in 1/21 (5%) in comparative group of seronegative adults; p = 0.004. Persistence of HCV-RNA in PBMC after combined treatment occurred in 5/10 (50%) patients resistant to previous IFN-alpha monotherapy, 6/35 (20%) of them cleared HCV from PBMC (p = 0.04). CONCLUSIONS: Age and gender, infection route, history of HBV infection or severity of histopathologic liver lesions had no influence on the efficacy of treatment with IFN-alpha and ribavirin. Clearance of HCV from serum and from PBMC occurs less frequently in patients previously resistant to IFN-alpha. Children with CHC require longitudinal observation after successful antiviral treatment as in 37% of those considered to be free from the virus by ordinary measures, HCV-RNA was found in PBMC.

Adolescent↗