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Biomedical subjects

J Horák

Publications and source records attributed to J Horák.

At least 19 recordsLinked to original sources
PubMed1996

Clinical importance of assessment of anti-HCV IgM antibodies in chronic hepatitis C.

In the majority of patients with acute hepatitis C the anti-HCV IgM antibodies in serum were present, however, some patients with chronic hepatitis C were positive for anti-HCV IgM too. The aim of this study was to assess the presence of anti-c22 IgM in patients with chronic hepatitis C and to determine whether the positivity for anti-c22 IgM has an impact on the histological finding in the liver. A total of 88 patients were examined (44 women, 44 men), mean age 48 years. The first group comprised 24 patients positive for both anti-HCV IgG and anti-c22 IgM, the second group 38 patients positive for anti-HCV IgG only, and the third group 26 patients negative for both anti-HCV IgG and anti-c22 IgM. Of 62 anti-HCV-IgG-positive subjects 24 (39%) were positive also for anti-c22 IgM. Of 24 patients who received a blood transfusion 9 (37.5%) were positive for anti-c22 IgM. The mean serum alanine aminotransferase (ALT) activity was significantly higher in subjects with anti-c22 IgM than that in subjects without them (p = 0.006), however, the difference in aspartate aminotransferase (AST) was not significant (p = 0.09). Histological examination was performed in 46 patients. Two-thirds of the patients with anti-c22 IgM had either cirrhosis or chronic active hepatitis (CAH) while only one third of the anti-HCV-positive patients without anti-c22 IgM had CAH or cirrhosis. The results showed that approximately 40% of the patients with CAH and cirrhosis had anti-c22 IgM, a significantly higher serum ALT activity and more serious histological finding in the liver than anti-HCV-positive patients without anti-c22 IgM.

Adolescent↗
PubMed1996

Effects of midazolam on glycemia and serum lipids in rats.

Midazolam administered ip. in albino rats (each group consisted from 10 animals rendered hyperdyslipidemic by the administration of Triton WR-1339) induced at most doses a significant reduction of glycemia (p < 0.001). However, the reduction of blood glucose level was outside of the dangerous level. Midazolam elicited also very significant decrease of the elevated serum lipids (p < 0.001). The pharmacological analysis of these phenomena by using the peripheral type benzodiazepine (BZD) receptors antagonist PK 11105, the central BZD receptor antagonist flumazenil and the purinergic P1 receptors antagonist aminophylline has shown that the effects on serum lipids were due, very probably to the stimulation of the peripheral type BZD receptors. Aminophylline seems to have the property to block the peripheral type BZD receptors. The effects on blood glucose level were very variable.

Aminophylline↗
PubMed1995

Effects of 4'-chlordiazepam on glycemia and serum lipids in hyperlipidemic rats: interactions with PK 11195 and flumazenil.

In rats rendered hyperlipidemic by the interperitoneal injection of Triton WR-1339, the administration of 4'-chlorodiazepam, a selective agonist of the peripheral type of benzodiazepine (BZO) receptors evoked significant reductions of serum lipids. PK 11195, a specific antagonist of these receptors, partially inhibited these effects. Flumazenil, a selective antagonist of the central BZD receptors, enhanced the lipid lowering activity of 4'-chlorodiazepam.

Animals↗
PubMed1994

Bone metastasizing renal tumor of childhood. A clinicopathological study of eleven cases from the Prague Pediatric Tumor Registry.

Eleven patients with bone metastasizing renal tumor of childhood (BMRTCh) who were diagnosed and treated in our departments over a 20-year period were reviewed. The incidence among all malignant renal tumors in children up to 15 years of age in our files was 3.7%. The male to female ratio was 10:1. The morphology had a uniform, predominantly clear cell finely vascularized pattern in all of them. Various previously recognized variations of the classic pattern such as hyalinization, nuclear palisading and cyst formation were observed in some patients. Electron microscopy showed that coarse vacuolization of the tumor seen at the light microscopic level was due to distended extracellular spaces surrounded by tumor cells and their cytoplasmic processes. Immunohistochemistry of the tumor cells revealed positive vimentin in all cases, and focally positive muscle specific actin in one. A prominent feature was fascicles of perivascular spindle cells. They were considered to be tumor cells rather than stromal elements since their morphology was close to the appearance of the polygonal tumor cells. The follow up data were available for ten patients. Four developed bone metastases, three of them died of the disease progression. Another patient died of lymph node dissemination and gastrointestinal bleeding. Six patients survived for a period of 29 months to 14 years following the diagnosis.

Bone Neoplasms↗
PubMed1994

[Surgical methods in the treatment of retroperitoneal neuroblastoma].

The authors submit their experience with the surgical treatment of retroperitoneal neuroblastoma, which is one of the most frequent solid tumours of child age. They describe the principles of the surgical technique with emphasis on radical removal of the tumour even in the area of large blood vessels. They emphasize the advantage of using an ultrasonic surgical aspirator (CUSA, Valleylab Co., Pfizer) which makes it possible to remove residues of the tumour without damaging the large blood vessels. During the period between 1987-1992 they treated at the Motol Faculty Hospital 69 children with retroperitoneal neuroblastoma. Of these 60 were operated. In the first stage of the disease 9 patients were operated, all survive. In the second stage 4 patients were operated, 75% survive, in the third stage 24 patients 50% survive, in the fourth stage 20 of 29 patients were operated and 11 (38%) survive. In stage IV--S three patients were operated, one survives. The total survival of patients during the investigation period is 52%.

Adolescent↗
PubMed1993

A morphological study of the effects of liposomized albendazole on the muscle phase of Trichinella spiralis in mice.

The pathomorphological effects of daily and weekly doses of liposomized albendazole on Trichinella spiralis larvae have been examined and compared during the course of muscle infections in mice. Treatment with three and six daily doses of the drug given by intraperitoneal injection to mice resulted in marked pathological alterations to encapsulated larvae, mainly in the walls of the capsules. There was a 5% efficacy against T. spiralis in mice given three daily doses of albendazole, and 38% efficacy in mice given six daily doses of the drug. The same doses of drug, when administered weekly, did not reduce the numbers of parasite larvae, and the application of drug at 6-weekly intervals resulted in a 5% reduction in numbers.

Albendazole↗
PubMed1993

Functional analysis of apf1 mutation causing defective amino acid transport in Saccharomyces cerevisiae.

Mutation in the Apf1 locus causes a pleiotropic effect of H(+)-driven active amino acid transport in baker's yeast Saccharomyces cerevisiae. The uptake of other, presumably H(+)-driven, substances, e.g. of purine and pyrimidine bases, maltose and phosphate ions, is not significantly influenced by this mutation. The apf1 mutation decreases not only the initial rates of amino acid uptake but also the accumulation ratios of amino acids taken up but has virtually no effect on the membrane potential or on the delta pH which constitute the thermodynamically relevant source of energy for their transport. Similarly, no changes in intracellular ATP content, in ATP-hydrolyzing and H(+)-extruding H(+)-ATPase activities, in the efflux of intracellularly accumulated amino acids, or in rates of endogenous respiration, were observed in the apf1 mutant phenotype. Hence, all these data are in accordance with the experiments showing that the Apf1 protein, an integral protein of the endoplasmic reticulum, is required exclusively for efficient processing and translocation of transport proteins specific for amino acids from the endoplasmic reticulum to their final destination, the plasma membrane.

Adenosine Triphosphate↗
PubMed1992

Transport of L-glutamic acid in the fission yeast Schizosaccharomyces pombe.

Transport of L-glutamic acid into the fission yeast Schizosaccharomyces pombe grown to the early stationary phase and preincubated for 60 min with 1% D-glucose is practically unidirectional and is mediated by a single uphill transport system with a KT of 170 microM and Jmax of 4.8 nmol min-1 (mg dry wt.)-1. The system proved to be rather non-specific since all the amino acids transported into the cells acted as potent competitive inhibitors. It has a pH optimum at 3.0-4.0, the accumulation ratio of L-glutamic acid is highest at a suspension density of 0.6-1.0 mg dry wt. per ml and decreases with increasing L-glutamic acid concentrations in the external medium. The system present in the cells after preincubation with D-glucose is unstable and its activity decays after washing the cells with water or after stopping the cytosolic proteinsynthesis with cycloheximide, with a half-time of 24 min in a reaction significantly retarded by phenylmethylsulfonyl fluoride, a serine proteinase inhibitor. The synthesis of the transport protein appears to be repressible by ammonium ions.

Biological Transport↗
PubMed1992

Thialysine-resistant mutants and uptake of lysine in Schizosaccharomyces pombe.

Mutants defective in lysine transport were isolated and characterized. After UV-mutagenesis colonies resistant to thialysine, a toxic analogue of lysine, were isolated and L-lysine uptake into the mutant strains was analyzed. Among the thialysine-resistant strains a group of mutants was found, where the half-saturation constant, KT, of the high-affinity transport system for lysine was higher than in the wild-type, the high-affinity transport system for basic amino acids being specifically affected. This was confirmed by a complementation test in which all the thialysine-resistant strains with a higher KT for lysine uptake belonged to one complementation group. Kinetic and genetic analysis showed that our mutants were identical with can1-1 mutants, showing that a single high-affinity system for the transport of basic amino acids exists in S. pombe.

Arginine↗
PubMed1992

Left main coronary artery stenosis.

Between 1 January, 1989, and 28 April, 1990, a total of 888 selective coronary arteriographies were performed at the Institute for Clinical and Experimental Medicine in Prague. Of that number, 58 findings were assessed as at least 50% stenosis of the left main coronary artery (LCA). Having applied exclusion criteria, 50 patients (i.e., 5.63% of all those examined) were entered into a retrospective study. They were 45 men (90.0%) and 5 women (10.0%) with significant cumulation of risk factors for IHD; more than half on them had a history of coronary event. The patients had marked symptomatology--NYHA Class III and higher angina pectoris was present in 96%, a low tolerance of exercise was found in 26 patients undergoing ergometry (average workload of 13 kJ and heart rate of 111/min); exercise testing was invariably evaluated as positive. Coronary angiography regularly revealed multiple coronary artery lesions; the right coronary artery was also involved in 90%; a collateral circulation was present in as little as 34%. The localization of coronary stenoses and the mostly preserved left ventricular mechanical function allowed operative management of IHD in 84% of cases. In the group of patients undergoing surgery, hospital mortality was 4.8%. On long-term follow-up (mean 6.2 months) of the group of patients operated on, 59.9% were free of problem, 31% had NYHA Class II angina pectoris, and there was no improvement at all in one patient only (2.4%). In the group provided conservative therapy (not operated on primarily for severe left ventricular dysfunction), one patient died of recurrent myocardial infarction and cardiogenic shock, 2 have NYHA Class IV angina pectoris, and the remaining subjects continue experiencing NYHA Class III problems.

Adult↗
PubMed1992

[Alcohol block of the celiac plexus in severe visceral pain].

The authors present their own experience with percutaneous alcohol block of the coeliac plexus. Between April 1988 and December 1991 they used it in 22 patients. Except one patient the others suffered from severe pain of abdominal organs associated with carcinoma of the pancreas. The first four operations were made using angiography, the remainder under CT control. During evaluation of results two weeks after the intervention complete regression of pain was recorded in six patients. A partial effect was achieved in 11 patients, and the intervention failed in five patients. The intervention was repeated in four patients. The authors emphasize that the procedure is relatively simple and safe, and if successful, makes it possible to reduce or even eliminate opiates. It improves the quality of the remaining life of the patient.

Aged↗
PubMed1992

[The effect of mechanical support of the heart on the extent of experimental myocardial necrosis. I].

The authors investigated the influence of mechanical cardiac support with a non-pulsating blood flow on the size of an ischaemic after ligature of the descendent branch of the left coronary artery in the dog. As compared with a control group of experimental animals where mechanical cardiac support was not used, the size of the necrotic focus of the heart muscle diminished by 50% (p less than 0.01). In some of the experimental animals the size of the necrotic focus did not change despite the use of a mechanical cardiac support. Analysis of haemodynamic parameters (assessed and calculated) revealed that for the fate of the necrotic focus of the myocardium the degree of relief (decompression) of the left ventricle is decisive. In complete relief the necrosis diminishes in size.

Animals↗
PubMed1992

[Endomyocardial biopsy].

The authors present ten years' experience with endomyocardiac biopsy of the heart (EMB) using the percutaneous, endovasal catheterization needle technique. EMB was performed in 314 patients, a total of 1362 biopsies, and for evaluation 5564 specimens of cardiac tissue were taken. Based on this experience the authors emphasize methodical principles which make expedient, rapid and safe collection of cardiac tissue specimens possible. They also mention the main indication criteria for endomyocardial biopsy. Endomyocardial biopsy is a valuable clinical examination method which, no doubt, holds its place in the series of diagnostic methods of modern cardiological catheterization departments.

Biopsy, Needle↗
PubMed1991

Protein transport and compartmentation in yeast.

Many newly synthesized proteins must be translocated across one or more membranes to reach their destination in the individual organelles or membrane systems. Translocation, mostly requiring an energy source, a signal on the protein itself, loose conformation of the protein and the presence of cytosolic and/or membrane receptor-like proteins, is often accompanied by covalent modifications of transported proteins. In this review I discuss these aspects of protein transport via the classical secretory pathway and/or special translocation mechanisms in the unicellular eukaryotic organism Saccharomyces cerevisiae.

Amino Acid Sequence↗