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Biomedical subjects

N Mahmood

Publications and source records attributed to N Mahmood.

52 records · Page 3Linked to original sources
PubMed1993

Asbestos induced oxidative injury to DNA.

DNA-damaging effects of asbestos in the presence of organic peroxides and hydroperoxides were investigated. The destabilization of the secondary structure of DNA, damage to deoxyribose sugar and DNA fidelity were measured, respectively, by S-1 nuclease hydrolysis, the formation of thiobarbituric acid (TBA)-reacting species and a melting temperature (Tm) profile using calf thymus DNA. S-1 nuclease hydrolysis and Tm determinations have shown that the presence of benzoylperoxide (BOOB), cumene hydroperoxide (COOH) or tertiary-butyl hydroperoxide (t-BOOH) increased asbestos-mediated DNA damage by a large factor compared either to asbestos alone or to peroxide or hydroperoxide alone. However, no formation of TBA-reacting species could be observed in this system. The quenchers of reactive oxygen species (ROS) afforded protection against DNA damage. These results suggest that asbestos in the presence of organic peroxides and hydroperoxides damage the DNA which is mediated by the generation of oxygen free radicals. The significance of these results in relation to the development of cancer of the respiratory tract among the asbestos exposed population is discussed.

Animals↗
PubMed1992

Aryl phosphate derivatives of AZT retain activity against HIV1 in cell lines which are resistant to the action of AZT.

Novel aryl phosphate derivatives of the anti-HIV nucleoside analogue AZT have been prepared by phosphorochloridate chemistry. These materials are designed to act as membrane-soluble pro-drugs of the bio-active free nucleotides. In vitro evaluation revealed the compounds to have a pronounced, selective antiviral activity, which, in one case, was more potent than the parent nucleoside AZT. The magnitude of the biological effect varied considerably with the nature of the phosphate-blocking group. Moreover, one of the compounds, a phosphoramidate, is particularly active in a cell line restrictive to the activity of AZT, due to poor phosphorylation therein. These data support the suggestion that the phosphate derivatives exert their biological effects via intracellular release of the nucleotide forms.

Antiviral Agents↗
PubMed1992

Constituents of Eriobotrya japonica. A study of their antiviral properties.

The CHCl3 extract of Eriobotrya japonica from an Italian source was shown to contain four new triterpene esters, namely, 23-trans-p-coumaroyltormentic acid [1], 23-cis-p-coumaroyltormentic acid [2], 3-O-trans-caffeoyltormentic acid [3], and 3-O-trans-p-coumaroylrotundic acid [4], in addition to three common ursolic acid derivatives 5, 6, and 7. An investigation of the antiviral properties of compounds 1-7 revealed that only 3 significantly reduced rhinovirus infection. The compounds were ineffective towards human immunodeficiency virus type 1 (HIV-1) and Sindbis virus replication.

Antiviral Agents↗
PubMed1992

Diminution in kerosene-mediated induction of drug metabolizing enzymes by asbestos in rat lungs.

In order to determine the pulmonary toxicity of kerosene and its ignition product (soot) in asbestos exposed subjects, the activities of phase I and phase II drug metabolizing enzymes in rat lungs after single intratracheal co-exposure to Indian chrysotile asbestos and kerosene or its soot and Indian chrysotile were assayed. Exposure to kerosene or its soot resulted in a significant increase in the level of microsomal cytochrome P-450 and the activity of P-450 dependent monooxygenase, benzo(a)pyrene hydroxylase, as well as in the activities of microsomal epoxide hydrase and cytosolic glutathione-S-transferase (GST). However, in chrysotile exposed animals a reverse pattern in these parameters was recorded. The co-exposure to chrysotile and kerosene or chrysotile and soot led to a significant depletion in cytochrome P-450 level and a decrease in the activities of benzo(a)pyrene hydroxylase, epoxide hydrase and GST when compared to kerosene and soot controls, respectively. These results suggest that asbestos by altering the pulmonary drug metabolizing enzyme system may increase the toxic potential of kerosene and its ignition product in the respiratory system.

Animals↗
PubMed1992

The desire for additional children among Pakistani women: the determinants.

"This study examines the determinants of the desire for additional children for currently married women in Pakistan, drawing data from the Population, Labour Force and Migration (PLM) Survey of 1979-80. The variations in the patterns of desired fertility and their relationship to...factors of economic and social change--such as education, husband's occupation, household income, child education, and work--are also analyzed. The analysis is conducted using logit regression models." Consideration is given to differences between rural and urban women.

Asia↗
PubMed1992

Motivation and fertility control behaviour in Pakistan.

Using data from the Population, Labor Force, and Migration (PLM) Survey of 1979-80, this paper examines the component of potential motivation for fertility limitation among Pakistani married women and then determines what factor are important in explaining the contraceptive use differentials among the potentially motivated subgroup of women. The analysis is conducted using logit regression models. The findings show that, among women wanting no additional children, a substantial proportion is reluctant to adopt fertility control behavior, confirming the existence of latent demand for contraception in all strata. A majority of those women report no exposure to the program or no contact with a family planning worker, and a large majority of those who have had exposure or have been contacted do not report contraceptive use, indicating a considerable shortfall of the program. Among the urban women wanting no more children, the important factors affecting contracepting use positively are education (both primary and secondary), household income, living in a nuclear family, exposure to the program, and contact with a family planning worker, for rural women, only nuclear family living and the program factors are significant in promoting contraceptive use. The suggestions likely to increase contraceptive prevalence are, first, to reach those women who have the potential motivation for contraception, and, second, to increase the quality and sources of the motivation efforts of the program to crystallize the latent demand among those who need it.

Age Factors↗
PubMedDate not supplied

Synthesis and anti-HIV activity of C4-modified pyrimidine nucleosides.

One-pot syntheses provided a series of triazole- and pentafluorophenyloxy-substituted pyrimidine nucleosides. Most of the compounds in the series displayed anti-HIV activities but none as potent as AZT 2. 1-(beta-D-Erythro-pentofuranosyl)-4-pentafluorophenyloxy-2(1H)-pyr imidinone 14 was the most potent and the most selective compound in the series with EC50 = 1.6 microM.

Anti-HIV Agents↗
PubMedDate not supplied

Literacy transition and female nuptiality: implications for fertility in Pakistan.

"This paper is an attempt to examine trends and differentials in education and age at marriage of males and females [in Pakistan] and then relate the two variables to one important aspect of demographic behaviour, namely fertility, and evaluate the implication of these relationships on reduction of fertility in Pakistan." The data are from the 1981 census and the 1979-1980 Population, Labour Force and Migration (PLM) Survey. "Given the limitations of the survey data which pertain to a sample of ever-married women between the ages of 15 and 49 years, the main conclusions of the study are that a rise in female age at marriage and education at secondary and higher levels are important in affecting fertility levels." Policy implications of the findings are discussed. Comments by Akhtar Hasan Khan are included (pp. 601-3).

Asia↗