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Biomedical subjects

J Molnár

Publications and source records attributed to J Molnár.

At least 145 records · Page 8Linked to original sources
PubMed1980

New mechanism of plasmid curing by psychotropic drugs.

Methylene blue enhanced the plasmid curing efficiency of chlorpromazine, imipramine and amitriptyline with strains of Escherichia coli K12 carrying F-prime lac or the resistance factor R-144. In contrast, methylene blue inhibited the elimination of plasmids by acridine orange and ethydium bromide at all concentrations tested. Two metabolic derivatives of chlorpromazine, chlorpromazine sulphoxide and 7.8-dioxochlorpromazine had no plasmid curing effect even in the presence of methylene blue. Amitriptyline, 7,8-dioxochlorpromazine and acridine orange were effective inhibitors of the conjugal transfer of the resistance plasmid, R-144, whilst methylene blue, chlorpromazine sulphoxide, and imipramine had only slight effects. We were therefore unable to demonstrate a simple correlation between curing ability and inhibition of plasmid transfer amongst the psychoactive drugs tested. A mechanism of plasmid curing by surface action of the drugs is suggested as an alternative to direct intercalation of the drugs into plasmid DNA.

Acridine Orange↗
PubMed1980

Effect of toluene inhalation on the liver of rats--dependence on sex dose and exposure time.

Groups of CFY rats were exposed to toluene inhalation as follows: both males and females to 1000 mg/m3 6 h daily five times a week for 6 months; only males to 3500 mg/h3 8 h daily every day for 6 months; and only males to 1500, 3000 and 6000 mg/m3 8 h daily for 4 weeks. Control groups were exposed to air inhalation under identical conditions. Toluene was found to inhibit growth but to cause no abnormal light-microscopical changes. Hepatic changes were: (i) Signs of compensation such as increased relative liver weight, SER proliferation; increased succinate dehydrogenase activity; a decrease in glycogen content; increased cytochrome P-450 and b5 concentration; increased hepatic aniline hydroxylase and aminopyrine N-demethylase activity. (ii) Non-specific subcellular effect was observed in a small number of hepatocytes, namely RER dilatation, separation of ribosomes, mitochondria of variable shapes, an increased number of autophagous bodies. As regards indicators of the hepatic function, BSP retention decreased, GOT and GPT activity did not change. The changes were observed in both sexes, were dose-dependent and reversible, and showed no--or only a slight--dependence on exposure time. Chronic toluene exposure has no specific hepatotoxic effect leading to chronic liver disease.

Animals↗
PubMed1979

Determination of enzyme activity by chromatography and videodensitometry. II. Urea cycle enzymes in tissue homogenates.

Methods are described for the determination of the activity of urea cycle enzymes in human and rat tissues by chromatography and videodensitometry(CV-technique). With specific substrates carbamoyl-phosphate synthetase and ornithine carbamoyltransferase activities were determined as the amounts of citrulline formed. Argininosuccinate synthetase, argininosuccinate lyase and arginase activities were measured from the changes in ornithine concentration. For measuring the activity of five enzymes 5 to 10 mg wet weight of tissue was sufficient. The CV-technique could be conveniently applied for the investigation of enzyme content in samples from human biopsy.

Animals↗
PubMed1979

Elimination of F'lac plasmid by different psychotropic drugs and some related compounds.

Desipramine, trimipramine, protriptyline, noxiptyline, promazine, trimeprazine, triflupromazine and chlorprothixene methoiodide eliminated the F'lac plasmid of Escherichia coli, while thiazinanum, toluidine blue, lidocaine and procaine were ineffective in this respect. The plasmid eliminating action of the drug ceased in the presence of 0.05 M magnesium sulphate. Methylene blue did not inhibit plasmid elimination by the psychotropic drugs, and in presence of the dye even lidocaine and procaine became effective. Based on plasmid elimination in the presence of methylene blue and on the selective effects of the lon- mutant, the plasmid eliminating mechanism of psychotropic drugs seems to differ from that of acridine orange.

Animals↗
PubMed1979

[Importance of arginine content and arginase activity in fertility].

Experimental studies have shown that in men with pathospermia the arginine content of sperm plasma is lower than in normal men. In order to find out the reason of this divergency the authors analysed the content of arginine, urea, citrulline, GAA and arginase activity in serum and in sperm plasma of 40 patients with normo-, oligo- or azoospermia. For the first time our results show that the low arginine content in pathological sperm is not due to disorder of the precursor metabolism, but to the increased arginase activity and to the increased conversion of arginine to GAA. In order to find out the mechanism of action and to develop an adequate andrological therapy detailed studies on molecular level have to be done.

Arginase↗
PubMed1979

[Ultrastructure and classification of epithelial thymomas].

4 epithelial thymomas out of 36 various types of it were studied electronmicroscopically. The following types were distinguished: clear cell thymoma, dark cell, solid thymoma, lacunar and spindle cell thymoma. These types of thymomas differ not only morphologically, but clinically. Authors suggest, that these tumours take their origin from the star-shaped clear- and dark medullar epithelial cells.

Epithelium↗
PubMed1978

Cleavage of pre-mRNA sequences by ribonucleases bound to nuclear RNP particles of rat liver.

The 30S nuclear RNP particles from rat liver have been shown to split the double-stranded- (ds) and single-stranded (ss) sequences of nuclear pre-mRNA. Experiments performed in vitro have demonstrated that 1) a 5'-exonuclease and an endonuclease specific for double-stranded pre-mRNA sequences exist in the 30S pre-mRNP particles; 2) in dsRNA monophosphorylated 5'-termini arose in the course of incubation with 30S RNP and most of the products remained double-stranded. The analysis of terminal pNp nucleotides revealed a relatively high ratio of pPyp in the cleaved dsRNA, whereas the nucleosides in 5'-terminal pNp of ssRNA showed nearly random distribution. Our results provide a possible explanation for the appearance of pNp termini during the processing of nuclear pre-mRNA of mammalian cells.

Animals↗
PubMed1978

Methylated cap formation by enzymes bound to nuclear informofer particles.

Rat liver nuclear 30 S ribonucleoprotein particles containing pre-mRNA and nuclear sap proteins have been shown to modify in vitro the synthetic dinucleotide ppGpC in the presence of GTP and S-adenosyl-L-methionine (SAM) by the formation of a blocked and methylated (capped) structure 7(meG(5')ppp(5'-GmepC. In the absence of SAM the predominant reaction was GpppGpC. Our results indicate that the 30S ribonucleoprotein particles (informofers) as well as the proteins of the nuclear sap possess both guanylyltransferase, N7-, and 2-o-methyltransferase activities.

Animals↗
PubMed1978

[Classical and modified intramedullary nailing in osteomyelitis pseudoarthroses].

13 cases of osteomyelitic pseudarthroses following injury were treated by the authors, by means of intramedullary nailing. 5 of these patients already cured are introduced in detail in the article. Intramedullary nailing in the classic manner and its modification, using bolts as well, were performed alike. The authors have a favourable impression after these series. No septic complication occured. Intramedullary nailing is a good method in the management of this serious sequel to fracture treatment.

Bone Nails↗
PubMed1978

Plasmid curing and antibacterial effects of some chlorpromazine derivatives in relation to their molecule orbitals.

7-Hydroxychlorpromazine, 7,8-dihydroxychlorpromazine and 7,8-dioxochlorpromazine exerted a bacteriostatic effect on Gram-positive and Gram-negative bacteria, with the latter being more resistant. The three compounds also had a bactericidal effect on selected strains of Escherichia coli and Staphylococcus aureus. 7-Hydroxychlorpromazine was able to cure 2% of F'lac plasmid of the E. coli K-12 LE 140 strain at 60 micrograms/ml, while 7,8-dihydroxychlorpromazine and its quinone failed to produced such an effect at the same concentration. In the presence of 0.1 M magnesium sulphate the plasmid curing effect of CPZ and 7-OH-CPZ decreased markedly, while the MIC values of CPZ and its derivatives increased. It seems therefore that the relative ineffectivity of CPZ in the presence of magnesium ions was not due to its metal chelation.

Bacteria↗