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Biomedical subjects

A Ray

Publications and source records attributed to A Ray.

At least 361 records · Page 20Linked to original sources
PubMedDate not supplied

A 61-kb ring chromosome shows an ARS-dependent increase in its mitotic stability in the mcm2 mutant of yeast.

We have studied the effects of ARS addition and deletion on the maintenance of a 61-kb ring derivative of chromosome III in a minichromosome maintenance mutant of yeast carrying the mcm2-1 mutation. When this ring chromosome, CIIIR, had either of its two strong origins deleted, the resultant chromosome showed a much greater instability in the mutant as compared to that of the wild-type strain. Integration of more ARSs improved the maintenance of CIIIR in the mutant but not in the wild-type strain. Increase in the size of CIIIR, without any ARS addition, did not improve the stability in either strain. A spontaneous revertant for improved growth at 35 degrees C also co-reverted for minichromosome and CIIIR maintenance. The results suggest that ARS malfunctioning leads to minichromosome and chromosome loss from mutant cells, affecting their growth at higher temperatures.

Adenosine Triphosphatases↗
PubMedDate not supplied

Increased uracil nucleotide metabolism during the induction of cardiac hypertrophy by beta-stimulation in rats.

The dynamics of uracil nucleotides was followed in the rat heart during the induction of cardiac hypertrophy by beta-adrenoreceptor stimulation. Isoproterenol (ISO) 5 mg . kg-1 was administered subcutaneously daily for 8 consecutive days. A significant increase in ventricular dry weight (40%) was observed on the 5th day of beta-stimulation, thereafter no further increase occurred. A single dose of ISO increased uridine triphosphate (UTP) concentration and the whole uracil nucleotide pool (UN). The increase was maximal (80 and 100%) 12 hours after ISO administration. The 32phosphate incorporation into the alpha-phosphate group of UN was increased by about a factor of 2 for the same period of time. Slight decrease in pool sizes (UTP and UN) and labelling occurred from 12 to 24 h after beta-stimulation. Similar changes also occurred on the 8th day of ISO administration, however modifications in concentrations and labeling were attenuated. The results show that modifications in the synthesis of UN should also be taken into account when studying the early events leading to cardiac hypertrophy.

Adenosine Triphosphate↗
PubMedDate not supplied

Serum lipid profile and its relationship with host immunity in carcinomas of the breast and uterine cervix.

Carcinomas of the uterine cervix and breast, which have a different etiopathogenesis, are the most common malignancies among Indian women. Between these two cancers a comparative study was undertaken in which serum lipids were assessed along with host immunity. Thirty randomly selected cases each of breast and cervical carcinoma, and 20 matched healthy control women were studied by means of standard procedures. Significantly higher (P < 0.001) mean levels of triglycerides (x = 192.1 mg/dl, SD +/- 113.5) and total cholesterol (x = 212.9 mg/dl, SD +/- 49.78) were observed in breast cancer as compared to controls or cervical cancer patients. Patients with cervical cancer had low mean values of all lipid fractions. Women with the above malignancies also showed a significantly decreased CD3+ and CD4+ population (P < 0.001), while there was a significant increase in CD8+ cells (P < 0.005) compared to normal controls. Interestingly, a significant relationship (P < 0.05) was observed between CD8+ cells and LDL-cholesterol among the cancer patients (r = 0.3652 and r = 0.4298 for carcinomas of breast and cervix, respectively.

Adult↗
PubMedDate not supplied

Glucocorticoid-induced enhancement of IgE synthesis.

Glucocorticoid-induced enhancement of polyclonal immunoglobulin production of the IgG, A, and M classes by human peripheral blood mononuclear cells has been shown to be dependent on regulatory T-cells. The following in vitro investigation demonstrated an enhancing effect of glucocorticoid on IgE production by mononuclear cells from atopic patients, but not by cells from non-atopic subjects. Augmentation was noted even in cell populations depleted of T cells and monocytes. These observations suggest that the corticosteroid acted directly on an IgE B cell at a late stage of differentiation that was no longer dependent on helper T-cells, although an additional effect on T-suppressor cells was not excluded.

B-Lymphocytes↗
PubMedDate not supplied

Recent trends in antifungal therapy: focus on systemic mycoses.

Amphotericin B (AmB) remains the 'gold standard' for systemic antifungal therapy and newer drug delivery systems have been effectively developed for this drug. The newer azoles e.g. itraconazole, voriconazole and their derivatives are viable alternatives to AmB, and are suitable for oral administration. Combination antifungal therapy has been tried successfully. For instance, AmB plus flucytosine is preferred in cryptococcal meningitis and candidemia. A liquid preparation of itraconazole and cyclodextrin is pharmacokinetically superior to the conventional dosage form of itraconazole, and is particularly effective in mycoses following cytotoxic chemotherapy and bone marrow transplants. Newer potential antifungals such as echinocandins, benanomicins/pradimicins, aureobasidins and nikkomycins are under clinical trials. The role of -immunomodulation in systemic anti-fungal therapy has been proposed and recombinant cytokine therapy (G-CSF, GM-CSF, IFN-g, IL-I, TNF-a) either alone or in combination with AmB have shown good results.

Antifungal Agents↗
PubMedDate not supplied

Comparative study of in vitro CD1a and HLA-class I antigens endocytosis by human thymocytes and Langerhans cells.

Langerhans cells and thymocytes were comparatively studied for their monoclonal antibody-induced endocytic activity. The two cell types were CD1a or Class I-HLA immunolabeled, incubated under similar conditions and the effects induced on membrane mobility were analyzed by a fluorescence method for the thymocytes and at the ultrastructural level for both cell types. We provide evidence that thymocytes are able to cap and internalize by receptor-mediated endocytosis CD1a antigen and Class I-HLA, whereas Langerhans cells present only a process of internalization by receptor-mediated endocytosis for both membrane antigens.

Antigens, CD1↗
PubMedDate not supplied

Effect of quinalphos on testicular steroidogenesis in rats.

The effect of quinalphos (250 micrograms/kg i.p.) an organophosphorus insecticide treatment for 13 and 26-days on the testicular steroidogenic enzymes viz. 3 beta-Hydroxysteroid Dehydrogenase and 17 beta-Hydroxysteroid Dehydrogenase, as well as cholesterol content and histology of the testes of the Wistar strain rats was studied. The time duration of 13 days is approximately equivalent to one cycle of the seminiferous epithelium in Wistar strain rats. Treatment of quinalphos for 13 days failed to produce any effect on the relative weights of the testes and accessory sex glands. However, significant inhibition of 3 beta-HSD activity and increased cholesterol level in testis were observed. The rats treated for 26 days similarly showed a highly significant inhibition of the activity of both 3 beta-HSD and 17 beta-HSD. The relative weights of the testes and accessory sex glands were also significantly reduced. Histological examination of the testis revealed that quinalphos treatment produced detrimental changes in the seminiferous epithelium. Treatment with quinalphos for 13-days produced no toxic effect with the exception of a significant increase in serum alkaline phosphatase. However, after 26-days of treatment toxicity was significantly increased as reflected on serum transaminases, phosphatases and blood urea levels of rat. Present study indicated that quinalphos impairs testicular functions in rats.

17-Hydroxysteroid Dehydrogenases↗
PubMedDate not supplied

Effect of aldrin on accessory sex glands and plasma testosterone levels in rats.

The effects of aldrin, an organochlorine insecticide, on accessory sex glands and plasma testosterone levels in rats were studied. The aldrin was administered i.p. for 13 days and 26 days at a dose of 150 micrograms/kg. Relative weights of prostate, seminal vesicles and coagulating glands were significantly decreased in the treated rats compared to those in controls. In addition, there was a significant fall in acid phosphatase activity in prostate and fructose content in accessory sex glands was also observed in treated animals. Plasma testosterone values showed a decrease with the duration of treatment. HCG supplementation with aldrin treatment prevented all those untoward effects of aldrin in experimental rats.

Acid Phosphatase↗