PubMed Health⌕ Search

Biomedical subjects

Z Lenghel

Publications and source records attributed to Z Lenghel.

15 recordsLinked to original sources
PubMed1993

Vitamin D3, a possible nuclear protector in normal hepatic and medullar tissue in white Wistar rats treated with cytostatics. Radioisotopic and cytogenetic aspects.

Vitamin D3 was given to male Wistar rats in 3 doses totalling 10,000 IU/kg b.w. then, within 24 hrs, girostan (10 mg/kg b.w.), lomustin or CCNU (10 mg/kg b.w.), all cytostatic substances, were injected in a single dose. Association of vitamin D3 with these cytostatics was found to reduce incorporation of 3H thymidine and a return to normal of RNA synthesis. This suggests that vitamin D3 has a protective effect by maintaining the stability of the double helix. Cytogenetically, the level of the recombinations and of the lesions themselves changes in relation to the structure of the alkylant used, and the damage is smaller if vitamin D3 is given before cytostatics.

Animals↗
PubMed1993

The combined action of thiotepa and lomustine cytostatics, of estradiol hormone and of vitamins E and A on Walker tumor chromatin structure.

The combined action of thiotepa (1 mg) and lomustine (3 mg) cytostatics, of estradiol hormone (0.05 mg) and of vitamins E (1 mg) and A (56 U) on Walker tumor chromatin of Wistar rats, was analysed. The cytostatics used determine modifications at chromatin DNA level, with the decrease of intact double helix proportion, as indicated by the analysis of chromatin thermal transition and of fluorescence intensity of chromatin-ethidium bromide complexes. Also, the determination of chromatin tyrosine and tryptophane intrinsic fluorescence denotes a diminution of the quantity of basic and acidic chromatin proteins under these cytostatics. The association of cytostatics administration with a treatment with estradiol or with vitamins E and A, determines a complex and specific change in the parameters analysed. Generally, the modulation under vitamins action consists of an increase in double helix chromatin DNA proportion, and of chromatin acidic proteins quantity. In the combined treatment estradiol-cytostatics, an increase takes place in basic and acidic proteins quantity coupled with DNA.

Animals↗
PubMedDate not supplied

[Rapid method of testing microbiol sensitivity to antibiotics].

The conventional technique for determining the sensitivity of bacteria to antibiotics is slow and a more rapid method becomes mandatory. The authors tested microbial sensitivity to antibiotics by measuring turbidity of the cultures in fluid medium. The method offers an orientation in the choice of an elective antibiotic within at most 4 hours.

Anti-Bacterial Agents↗
PubMedDate not supplied

Delayed cell cycle kinetics and chromosome aberrations induced by girostan in human peripheral blood lymphocytes (PBL) in vitro. Note 1. Modified S-phase traverse.

Human peripheral blood lymphocytes (PBL) maintained in vitro for 72 hours were labeled with 5-Bromodeoxyuridine (BrdU) at 50 microliters/ml and concomitantly treated with girostan at 1.5; 2 and 2.5 micrograms/ml during the last 13; 11; 9; 7; 5 and 3 hours before cells gathering for incorporation banding analysis in metaphase spreads. Similar untreated cultures, labeled with BrdU for the same time intervals were set up as controls in order to determine the phase of cell cycle traverse in the moment when girostan was given to the cultures. When compared with controls, incorporation banding pattern in treatment samples revealed the effect induced by girostan on cell cycle kinetics during different time intervals before mitosis. Cells with entirely dark chromosomes at metaphase [were] considered in G1/G2 phase, while metaphases with a clear banding on the chromosome were presumed to be at different moments within S-phase. Connected to the observed type of banding (R or G), early S, middle S and late S-phase metaphases were identified. A dose-related delay of cell cycle traverse was induced as revealed by the increased frequency of cells that lasted in S-phase and did not reach the G2-phase. More than that, within S-phase population, an evident accumulation of cells traversing middle S-phase was observed at the same time with the decrease of cells in late S. This effect of girostan on cell kinetics is also correlated with the moment during the cell cycle traverse when cytostatic treatment is gives.(ABSTRACT TRUNCATED AT 250 WORDS)

Bromodeoxyuridine↗
PubMedDate not supplied

Delayed cell cycle kinetics and chromosome aberrations induced by girostan in human peripheral blood lymphocytes (PBL) in vitro. Note 2. Chromosome aberrations.

Human peripheral blood lymphocytes (PBL) maintained in vitro for 72 hours were labeled with 5-Bromodeoxyuridine (BrdU) at 50 ug/ml and concomitantly treated with girostan at 1.5; 2 and 2.5 ug/ml during the last 13; 11; 9; 7; 5 and 3 hours before cells gathering to estimate the chromosome aberrations induced during different stages of cell cycle traverse as determined by incorporation banding pattern observed in metaphase spreads; similar untreated cultures but labeled with BrdU were set-up as controls in order to determine the phase of cell cycle traverse in the moment when girostan was given to the cultures. Chromosome aberrations were induced especially when treatments were performed 13 and 11 hours before fixation. Their frequency was rather low (up to 7% of observed metaphases) and the lesions were not dose-related. When cells were treated during S- and G2-phases, chromatid and chromosome gaps, breaks, deletions and fragments were observed. Chromatid rearrangements as tri- or quadriradials were seen only when girostan was given during middle S-phase indicating that DNA breaking and misrejoining are successive steps during the same replication round. When cells were exposed to BrdU and girostan during the last 3 hours of incubation, no labeled metaphase or structural aberration was seen, but spiralization defects and premature separation of despiralated chromatids frequently appeared. This could indicate that the induction of chromosome condensing factor and of proteins responsible for normal centromere activity is disturbed when girostan treatment is applied during the last part of G2-phase, in the immediate proximity of mitosis.

Bromodeoxyuridine↗
PubMedDate not supplied

Mechanisms involved in differential staining of BrdU substituted chromatids or chromosome regions.

PHA stimulated peripheral blood lymphocytes were in vitro labelled with BrdU for 72 h. before cells gathering. Chromosome spreads were obtained by a standard method and some different techniques were used for differential staining of sister chromatids: a) denaturation of BrdU substituted DNA by thermal (90 degrees C) and alkaline (pH 9) treatments: b) UV-induced photolysis of substituted DNA pretreated with intercalating fluorescent agents (acridinorange or 33258 Hoechst) followed by heat treatment (60 degrees C); c) UV-induced photolysis and heat treatment (60 degrees C) without any fluorescent dyes or buffers. With this technique, incorporation banding was also obtained in cells labelled with high concentrations of BrdU during the last round of DNA replication. In all these methods the slides were finally coloured with Giemsa solution. The results obtained with each of the techniques used were compared and the possible molecular mechanisms involved were discussed. Even if many experimental factors could be of importance for revealing the BrdU substituted chromatids or chromosome segments, UV-irradiation and/or heat treatment appear to be mandatory for both differential staining of sister chromatids and for incorporation banding.

Bisbenzimidazole↗