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Biomedical subjects

N P Bishun

Publications and source records attributed to N P Bishun.

At least 19 recordsLinked to original sources
PubMed1982

The chromosomal effects of the oral contraceptive.

A general review of reports on the chromosomal effects of oral contraceptive has been undertaken, and it is quite apparent that there is a scarcity of literature on these very important investigations. Also, those that have been undertaken, cannot be properly assessed on account of, one supposes, subjects' background and lack of numbers, differences in techniques and, above all, the small number of metaphases analyzed. Apart from the report by Mills and colleagues [16], none of the reports mentioned exogenous agents to which the subjects might have been exposed, especially in cases where there has been an increased frequency of chromosomal aberrations. All these considerations must be taken into account for, as yet, the reports are too conflicting to 'indict' the oral contraceptive as having chromosome-breaking properties.

Chromosome Aberrations↗
PubMed1981

The role of cytogenetic tests in detection and prevention of cancer.

Although simplified and improved techniques have increased at a fast rate in recent years, a great number of compounds released into our environment still remain untested. It has been estimated that between 80-90% of human cancer is a result of exposure to such compounds, and if by the application of short-term mutagenic tests, the use of many of these compounds can be severely restricted, an enormous impact can be made on the solution of human health problems. Batteries of mutagenic tests have established an empirical relationship between mutagenisis and carcinogenisis, and, in view of the cost in terms of time and money, short-term tests are playing an important role in first detecting, and second, eliminating potential hazards in our environment. The use of bacteria and other unicellular organisms in these assay systems has met with much criticism; due to the fact that the DNA materials affected do not directly relate to that of man. However, in conjunction with other tests, utilizing human and other mammalian cells, firm conclusions can be drawn regarding the potential hazards of certain chemicals. Recent advances in cytogenetic tests (e.g., banding chromosomes and sister chromatid exchange) have improved the sensitivity of chromosomal tests and, in so doing, have rendered them more usual in the selecting out process that can reduce substantially the mutagenic and carcinogenic hazards caused by chemicals and other deleterious agents in the environment.

Animals↗
PubMed1980

Relationship between X chromosome activation, Barr body frequency and oestrogen receptor status in human breast cancer: a hypothesis.

Current evidence indicates an association between oestrogens, sex chromatin frequency and X chromosome activation in relation to the activity of the enzyme glucose-6-phosphate dehydrogenase. We suggest that a similar association might apply to control the level of oestradiol receptors in breast tumours and present information supporting this hypothesis.

Breast Neoplasms↗
PubMed1979

The effect of ascorbic acid on RNA and protein synthesis on two cultured cell lines in vitro.

Previous work in this laboratory has thrown some light on the possible mechanism involved in the anti-tumour activity of ascorbic acid (AA). In order to elucidate this mechanism further, the present studies, involving the effect of AA on protein and RNA synthesis, were carried out. The results obtained in this investigation may support the hypothesis previously put forward for the action of AA on cell proliferation.

Ascorbic Acid↗
PubMed1978

Bleomycin (review).

Since the original observation and description of the various forms of Bleomycin (BLM), numerous articles have appeared dealing with the activity on mammalian cells and its possible clinical use. The present review on this very important compound, although not very comprehensive, deals with the important characteristics; such as the action of DNA and cells, and its chromosome breaking effects. The manner in which the minute detail of the action of BLM on cells has helped to implement in vivo chemotherapeutic regimes, is also discussed.

Animals↗
PubMed1978

The effect of bleomycin on rat bone marrow cells.

Experiments were carried out to determine the cytogenetic effects of the antibiotic bleomycin (BLM) in rats using the bone marrow system. A total of eighteen male and eighteen female Sprague-Dawley rats were injected with varying concentration of BLM, over varying periods of time. The results revealed that at low concentrations BLM showed no alteration in the ploidy or the morphology of rat chromosomes. This however, was not the case when the dose or administration period was increased.

Animals↗
PubMed1977

Carcinogenic and possible mutagenic effects of stilboestrol in offspring exposed in utero.

The relevant literature has been reviewed and it appears that there is no doubt that in utero exposure to stilboestrol is related to the eventual development of vaginal adenocarcinoma in young females. Although cancer of other types are also prevalent, the incidence is not great and may be related to other types of drugs taken during pregnancy. The review attempts to correlate the genetic effects with the abnormal development, but on account of the scarcity of data such correlation is not possible. Further work on the genetic effects and the development of the lower genital tract in the female needs to be carried out.

Abnormalities, Drug-Induced↗
PubMed1977

Tissue culture of human breast tumours.

Several media have been used in an attempt to assess the most appropriate combination of ingredients to effect good cell growth from human breast tumours. Good epithelial cell growth has been obtained in 60 out of a group of 160 tumours successfully cultured in four types of basic media. The other tumours were fibroblastic in nature or contained a mixture of epithelial and fibroblastic cells.

Adenocarcinoma, Scirrhous↗
PubMed1976

Lymphocyte transformation in newborns, women and those who had used oral contraceptives.

Lymphocyte transformation, utilizing the mitotic index parameter has been assessed in newborns' cord blood, adults and women who had been on oral contraceptives and their babies. The results show that the newborns' cord blood response is significantly higher to PHA when compared with the respective adults' response. No significant difference was observed between the women taking oral contraceptives and their respective controls.

Adult↗