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Biomedical subjects

V Jain

Publications and source records attributed to V Jain.

At least 163 records · Page 9Linked to original sources
PubMed1991

Production of Tsr factor by Rhizobium meliloti.

The root exudates of alfalfa (Medicago sativa) and mungbean (Vigna radiata) induced the Tsr (thick and short roots) factor production in Rhizobium meliloti. The factor caused a 30-40% reduction of root length in alfalfa seedlings. Pea root exudate had no Tsr induction activity. The flavonoid naringenin could replace the roots in inducing Tsr production. Naringenin-induced Tsr factor caused 70% shortening of main roots. The Tsr inducing property of naringenin was specific since quercetin and syringaldehyde had no such effect.

Bacterial Proteins↗
PubMed1991

Early memories as expressions of relationship paradigms: a preliminary investigation.

Earliest childhood memories (EMs) have been utilized as expressions of relationship paradigms, but few empirical studies have been conducted. This study outlines the construction and development of an EM relationship scoring system and scale utilizing nonclinical and clinical samples. It was hypothesized that relationship episodes could be reliably coded using EMs and that they would demonstrate convergent validity with measures of attachment style (Separation-Individuation Test of Adolescence), mood (Profile of Mood States), and clinical symptomatology (Symptom Checklist 90-revised [SCL-90-R] and the Minnesota Multiphasic Personality Inventory [MMPI]). The hypotheses received broad support. Findings indicate that relationship episodes may be reliably coded from EMs. Associations between individual EM variables, the EM relationship scale, and objective measures suggest that the quality of relationships expressed in EMs is associated with degree of general maladjustment. Suggestions for further research are discussed.

Adult↗
PubMed1991

Effects of gamma-rays and glucose analogs on the energy metabolism of a cell line derived from human cerebral glioma.

Effects of gamma-rays and glucose analogs, 2-deoxy-D-glucose (2-DG), 5-thio-D-glucose (5-TG) and 3-O-methyl glucose (3-O-MG) on cellular energy metabolism have been studied in a cell line, derived from a human cerebral glioma, by analysing intermediates of glycolysis and some important nucleotides (ATP, NAD etc.) using the technique of isotachophoresis. Gamma-irradiation induced a transient decrease in the nucleotide levels accompanied by an accumulation of sugar phosphates, the nucleotide levels recovering in a few hours post-irradiation. 2-DG inhibited glycolysis and reduced the nucleotide levels of irradiated as well as unirradiated cells in a concentration-dependent manner both in presence and absence of respiration, whereas 5-TG and 3-O-MG did not show significant effects in the presence of respiration. Reduced energy status observed with 2-DG under respiratory proficient conditions was completely reversed in 2 hr following its removal, whereas such a recovery was not observed in the absence of respiration. These results have important implications in the energy-linked modifications of tumour radiation response using glucose analogs.

3-O-Methylglucose↗
PubMed1991

Effects of 5-bromo-2-deoxy-uridine and 2-deoxy-D-glucose on the radiosensitivity of proliferating transformed mammalian cells.

Effects of 5-bromo-2-deoxy-uridine (BrdU) and 2-deoxy-D-glucose (2-DG) were studied in exponentially growing transformed mammalian (BHK-21) cells, grown as monolayer. Micronuclei formation as an index of radiation damage was studied by i) cytokinesis block technique from cytochalasin-B induced binucleated cells, and ii) conventional technique. Presence of BrdU (0.8 microM) for nearly 2 cell cycles before gamma-irradiation (2.5 Gy) significantly increased frequencies of cells with micronuclei. Post-irradiation incubation of cultures in liquid holding medium (HBSS) however, reduced micronuclei formation, especially in the BrdU treated cells. Presence of 2-DG (4 hr, equimolar with glucose) in growth as well as liquid holding medium further increased micronuclei frequencies. These observations suggest that radiation induced DNA lesions in BrdU substituted cells, leading to chromosome fragmentation are partly repairable. 2-DG increased cytogenetic damage, possibly by inhibiting the repair of such repairable lesions. Present studies suggest that combination of 2-DG could optimize BrdU-radiation therapy of brain tumors, by reducing the BrdU doses required for tumor radiosensitization.

Animals↗
PubMed1990

Effects of 5-bromo-2-deoxyuridine and 2-deoxy-D-glucose on radiation-induced micronuclei in mouse bone marrow.

Effects of 2-deoxy-D-glucose (2-DG) and 5-bromo-2-deoxyuridine (BrdU) on 60Co gamma-radiation-induced damage in normal mouse bone marrow have been investigated. Cytogenetic damage as measured by the frequency of cells with micronuclei was studied at various time intervals after irradiation. Intravenous administration of 2-DG (0.1 ml, 1 g/kg body weight) just before or after whole-body irradiation (absorbed dose 2.5 Gy) significantly reduced the micronuclei fraction as compared with irradiated controls. Incorporation of BrdU given intraperitoneally in 13 injections (0.3 ml) (total dose 2 g/kg body weight) at intervals of 1 h increased the micronuclei frequency, but administration of 2-DG significantly decreased cytogenetic damage. The results have interesting implications for improving tumour radiotherapy.

Animals↗
PubMed1990

Microcalorimetric studies on cell survival and repair after UV induced damage.

Rate of heat production during cell proliferation following UV-irradiation of respiratory-deficient yeast cells was measured as a function of time (p-t curve) in a batch microcalorimeter. Following observations were made: (a) All growing cell cultures showed 3 distinct phases of heat production namely lag, exponential and declining phases of rate of heat production. (b) Duration of the lag phase is inversely proportional to the number of cells capable of proliferation. (c) After UV-irradiation, lag phase increased in a dose dependent manner. (d) Liquid-holding reactivation increased the surviving fraction and reduced the lag phase in p-t curves. Presence of 2-deoxy-D-glucose during liquid-holding prevented the reduction in lag phase due to the inhibition of repair processes.

Calorimetry↗
PubMed1990

In vitro radiation responses of human intracranial meningiomas & their modifications by 2-deoxy-D-glucose.

Radiation responses of 16 human intracranial meningiomas [hemangiopericyte, 4; fibrous, 4; transitional, 4; vascular, 3; and meningiothelial, 1] and their modifications by 2-deoxy-D-glucose (2-DG) have been studied in vitro using organ cultures derived from post-operative tumour specimens. Treatment induced cytogenetic damage viz., micronuclei formation and DNA content dispersion, were analysed as indices of the radiation damage. Results showed that the 60Co gamma ray induced micronuclei frequencies in meningiomas varied over a large range (0.7-6.2%). Presence of 2-DG (at equimolar concentration with glucose) for 4 h after irradiation, increased the radiation damage by a factor of up to 2.8 in nearly 70 per cent of the cases, although a decrease was observed in 20 per cent cases. These observations can be explained on the basis of the energy linked modulations of the competitive processes of repair and fixation of radiation induced DNA lesions. The results of the study suggest that the therapy of meningiomas could be improved by combining radiotherapy with administration of 2-DG.

Brain Neoplasms↗
PubMed1989

Effects of hematoporphyrin derivative on the cellular energy metabolism in the absence and presence of light.

Effects of Photofrin II on energy metabolism and metabolic viability were studied in a mammalian transformed cell line (BHK-21) in dark and after photo-irradiation with visible light. Cells were allowed to accumulate Photofrin by incubating for 4 h in buffer containing Photofrin (5-60 micrograms/ml). The results show that Photofrin significantly affects the cellular energy metabolism even in the absence of light; activity of cytochrome c oxidase is decreased and glucose utilization and lactate production (glycolysis) are increased. Irradiation with light resulted in a significant decrease in the activity of cytochrome c oxidase, glycolysis, ATP content, energy charge, ratios of adenine nucleotides like ATP/ADP, ATP/AMP and cell viability (dye exclusion test). Presence of inhibitors of energy metabolism, potassium cyanide (respiration) and 2-deoxyglucose (glycolysis), further enhanced the cytotoxic effects induced by hematoporphyrin derivative and light.

Adenine Nucleotides↗
PubMed1989

Effects of some divalent metal ions on the aging phenomenon of hematoporphyrin and photofrin II.

Dilute aqueous solutions of hematoporphyrin (Hp) and its derivative (Hpd or PF II) have been found to undergo a transformation (aging) on keeping at room temperature leading to (i) shift of the Soret band from 395 nm to 405 nm, (ii) disappearance of visible bands I (610 nm) and IV (503 nm) and (iii) shift of the first emission band from 615 nm to 580 nm. The transformation was concentration dependent. The effects of concentration and temperature on the absorption spectra were much more pronounced in Hp than in Photofrin II (PF II). Variation of pH resulted in changes in the relative intensities of the absorption bands, possibly due to formation of different ionic species at different pH. The rate of transformation was accelerated in the presence of Zn ions (0.01 microM) and considerably increased at higher (50 microM) concentration. The effect of Cu ions was different from the effect of aging. It formed the metal-chelate even when present in very small amounts. The results (absorption and fluorescence analysis) suggest that in dilute solutions (conc. less than or equal to 2 microM) of Hp and PF II, Zn ions present in glass and water as impurity, deform the porphyrin nucleus leading to changes in the conjugated ring symmetry and hence changes in the absorption and fluorescence spectra, while in higher concentrations (greater than 2 microM) it forms the metal chelate as evidenced by their absorption and fluorescence spectra.

Chemical Phenomena↗