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M Brezina

Publications and source records attributed to M Brezina.

34 records · Page 2Linked to original sources
PubMed1985

Antifibrillatory properties of alinidine after coronary artery occlusion in rats.

Ligation of the left anterior descending coronary artery was performed in open-chest anaesthetized rats and mortality as well as changes in ECG were evaluated for 30 min thereafter. Saline or drugs were administered 15 min prior to ligation. In the control group, following a 4 min lag period ventricular arrhythmias as single ectopic beats, ventricular tachycardia and ventricular fibrillation (VF) appeared, reaching a maximum between 10 and 20 min and disappearing after 30 min. Mortality (40% in the control group) coincided with the period of maximal arrhythmias, with VF more common in animals that died than in those surviving. Alinidine, a drug which reduces sino-atrial rate specifically but has no conventional antiarrhythmic properties, reduced mortality and VF. By means of order statistics the quantity 'risk of death' was used for evaluation of drug effects, considering incidence of death and VF as well as duration of VF. This quantity was reduced in correlation with the dose of alinidine (1-6 mg/kg i.v.) and in correlation with the reduction of heart rate. Mexiletine, an antiarrhythmic drug with membrane-depressant properties, also reduced the 'risk of death' dose dependently (1-10 mg/kg i.v.), but there was no correlation with a decrease in heart rate. It is suggested that alinidine reduced 'risk of death' by means of a reduced oxygen demand due to a decrease in heart rate.

Animals↗
PubMed1985

Lipolytic activity of renal cortex during ontogenetic development in rats.

The lipolytic activity of rat kidney cortex was investigated in newborn and adult rats. Two peaks of lipolytic activity could be detected at pH 5.0 and 8.4, respectively. Lipase activity at pH 5.0 is completely inhibited by 0.2 M sodium fluoride and can be stimulated by norepinephrine (10 micrograms/ml). Full activity is already present in 5-day-old rats. The response to sodium fluoride and norepinephrine is identical in newborn and adult animals. Lipase activity at pH 8.4 is inhibited up to 85% by 0.6 M sodium chloride. Activity is very low in 5-day-old rats and increases during maturation. This lipase can be stimulated by heparin (100 micrograms/ml) by about 10-25% in newborn and adult animals.

Aging↗
PubMed1984

Some aspects of renal energy and lipid metabolism in newborn rats.

Some aspects of renal energy and lipid metabolism were studied in the postnatal period of rats. Oxygen consumption, RQ values, stimulation of oxygen consumption by exogenous substrates (8 mM glucose, 8 mM acetate, 1 mM palmitate), and conversion of acetate or palmitate to CO2 were measured in slices of cortex and inner medulla. The results obtained in 5-day-old rats are not essentially different from those observed in adults. On the other hand, the phenomenon of triacylglycerol storage in kidney cortex during starvation (well known in adult animals) is absent in the newborn rat. It can be demonstrated first in 30-day-old rats. At the same age renal arteriovenous concentration differences for total glycerol indicate a significant uptake during starvation and a release in the fed state.

Animals↗
PubMed1983

Pulmonary functions in children exposed to polluted air.

In a preliminary study of the effects of polluted air on the functional pulmonary profile in children, 101 children living in an area with heavy air-pollution (Group B) and 103 children from an area with relatively non-polluted air (Group A) were examined. In Group B we found out a significant impairment of the parameters of the flow-volume curve at low volume levels of air in lungs, i.e. FEF25, FEF25/FVC and FEF50/FVC. Tiffaneau's index FEV1% was impaired significantly in girls only. This impairment may be an expression of the peripheral airways lesions due to chronic exposure to polluted air.

Air Pollution↗
PubMed1980

HBe-Antigen in the course and prognosis of hepatitis B infection: a prospective study.

The prognostic significance of the HBe-antigen (HBeAg) in the course and outcome of type B hepatitis was studied prospectively in 71 susceptible oncology patients. The patients had been exposed to tumor cell vaccines inadvertently contaminated with hepatitis B surface antigen (HBsAg)-containing plasma. Forty-five patients (63%) were infected. These 45 showed three types of acute seroresponse: HBsAg and HBeAg, 28 patients (62%); HBsAg alone, 8 patients (18%); and a primary antibody to HBsAg (anti-HBs) response, 9 patients (20%). There was no significant difference in acute course and outcome between the two HBs-antigenemic groups. All primary anti-HBs responders had asymptomatic infections. Seventeen patients receiving chemotherapy during the period of hepatitis B exposure were significantly more prone to symptomatic infection with acute HBs-antigenemia, and 2 of these patients developed chronic active hepatitis. The HBeAg is common early in acute hepatitis B among solid tumor patients and at this stage in disease has no prognostic significance independent of HBsAg.

Adult↗
PubMed1979

Penetration of beryllium through the placenta and its distribution in the mouse.

Penetration of beryllium through the placenta and its distribution in the organs after intravenous administration of BeCl2 in a dose of 0.1 mg/kg was studied in a series of experiments on ICR SPF mice. To trace the fate of beryllium, an isotope in the form of 7BeCl2 in an amount of 111kBq per animal was used. This dose was administered to a group of females before fertilization, on the 7th and 14th day of pregnancy, and to control animals. The animals were killed on the 18th to 19th day of pregnancy and the content of beryllium in the foetuses and its distribution in the organs of the mothers were determined by measuring activity. It has been found that beryllium penetrates through the placenta with difficulty, however, part of the dose administered circulated in the blood long enough for Be to penetrate the foetuses. Of interest is the finding that beryllium in the dose administered influenced the number of foetuses of the exposed females. This finding deserves detailed evaluation in the test of dominant lethal mutations.

Animals↗
PubMedDate not supplied

Automated RIBA HCV strip immunoblot assay: a novel tool for the diagnosis of hepatitis C virus infection in hemodialysis patients.

Hemodialysis (HD) patients remain a high-risk group for hepatitis C virus (HCV) infection. Serological assays (enzyme-linked immunosorbent assays, ELISAs) are the only tests currently approved by the Food and Drug Administration in the United States for the diagnosis of HCV. The RIBA HCV Strip Immunoblot Assay (SIA) is an established method for supplemental testing of repeat reactive hepatitis C ELISA patients on HD. However, the current manual procedure is labor intensive, requiring subjective band scoring and result interpretation. Recently, the automated CHIRON RIBA HCV Processor System has been designed to perform RIBA supplemental testing. The CHIRON RIBA HCV Processor System consists of a bench-top instrument that provides objective evaluation of the RIBA immunoblot strips, by measuring the light differentially reflected from the developed bands and white background, creating a density of reflectance. The CHIRON RIBA HCV Processor System assesses the intensity of each of the reactive bands in relation to the intensity of the internal control bands on each RIBA HCV strip. Comparison between processor and manual protocols was performed using a large (n = 200) cohort of ELISA 3.0 HCV negative and positive patients on maintenance HD. The test characteristics of RIBA HCV 3.0 SIA were identical with manual and automated runs. The relative intensity values of antigenic bands by the CHIRON RIBA HCV 3.0 Processor System between anti-HCV positive and negative patients were significantly different; only 15 of 784 (1.9%) antigenic bands had borderline reactivities. The correlation of test results between manual and automated runs was very high (kappa value 0.989). Among positive results by RIBA HCV 3.0 SIA, there was a strong concordance between manual and automated runs with regard to the pattern of reactivity (kappa value 0.943). The discordant results between manual and automated protocols were attributable to increased variability of antigen scores close to the cutoff value for both tests. In conclusion, the CHIRON RIBA HCV 3.0 Processor System is capable of performing RIBA HCV 3.0 SIA in the HD population accurately with minimal operator involvement. The test characteristics of RIBA HCV 3.0 SIA were identical by manual and automated runs. There was a strong correlation between the results of the manual and automated runs; the few discordant results between the two procedures were mostly due to increased variability of antigen scores close to the cutoff value for both tests. The Centers for Disease Control and Prevention in the USA have recently included chronic HD patients among those persons for whom routine HCV testing is recommended; HCV-infected patients on HD often have a high rate of indeterminate results by manual RIBA technology which is operator dependent for band scoring and result interpretation. The CHIRON RIBA HCV 3.0 Processor System may be very useful for supplemental anti-HCV testing of ELISA repeat reactive specimens in clinical practice within dialysis units.

Hepatitis C, Chronic↗
PubMedDate not supplied

Magnetic resonance imaging in children receiving quinolones: no evidence of quinolone-induced arthropathy. A multicenter survey.

Twenty-nine children with cystic fibrosis (CF) were investigated for quinolone-induced arthropathy. Magnetic resonance imaging (MRI) was performed in 14/14 children treated with ofloxacin or ciprofloxacin and in 10/15 of those never treated with quinolones. The frequency of pathologic MRI findings, concerning cartilage thickness, careful analysis of the cartilage structure, presence of edema, cartilage-bone borderline and the presence of fluid in joints did not show any difference between both groups. Thus the presence of quinolone-induced arthrotoxicity cannot be confirmed in this study.

Adolescent↗
PubMedDate not supplied

Pulmonary complications in patients with inflammatory bowel disease.

BACKGROUND/AIMS: Between 1996 and 1998 we investigated the occurrence of lung disorders in 82 patients with inflammatory bowel disease (30 patients with ulcerative colitis and 52 patients with Crohn's disease) and a control group of 60 subjects. The aim of our study was to determine the occurrence of pulmonary complications in patients with inflammatory bowel disease, to investigate whether ulcerative colitis or Crohn's disease are connected with a typical lung function disorder, with the inflammatory activity of the disease or if they depend on the presence of other extraintestinal manifestations. METHODOLOGY: We investigated the occurrence of lung disorders in terms of the following parameters: clinical pulmonary symptoms, chest radiography and pulmonary function tests (body plethysmography, pneumotachography, lung transfer capacity for carbon monoxide, and blood gas analysis). RESULTS: Lung function abnormalities were significantly more frequent in patients with inflammatory bowel disease as compared to controls (p<0.001). There was no apparent correlation between these abnormalities and either bowel disease activity or drug administration (sulphasalazine, mesalazine). CONCLUSIONS: Despite the lack of radiological abnormalities, we identified a high incidence of pulmonary function abnormalities (suspicious of interstitial lung disorder) in patients with inflammatory bowel disease; 56.7% of patients with ulcerative colitis and 57.7% of patients with Crohn's disease had reduced lung transfer factor.

Adolescent↗
PubMedDate not supplied

Reference values and modelling of lung function development as a transcendent function of age, body height and mass.

We present new lung function reference values based on an investigation of 1024 healthy subjects aged 6-81 years. The dependent variables, i.e. VC, FEV1, RV, FRC, TLC, PEF, MEF50 and MEF25 are expressed as transcendent functions of age, body height and mass. A single equation covers the age range from 6 to 81 years and reflects certain phenomena such as growth, maturation, ageing, sex differences and the undermass-overmass effect. This allows a more accurate determination of individualized reference values and normal limits.

Adolescent↗