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Biomedical subjects

J S Fry

Publications and source records attributed to J S Fry.

26 records · Page 2Linked to original sources
PubMed1983

Expression of bacterial genes in plant cells.

Chimeric bacterial genes conferring resistance to aminoglycoside antibiotics have been inserted into the Agrobacterium tumefaciens tumor-inducing (Ti) plasmid and introduced into plant cells by in vitro transformation techniques. The chimeric genes contain the nopaline synthase 5' and 3' regulatory regions joined to the genes for neomycin phosphotransferase type I or type II. The chimeric genes were cloned into an intermediate vector, pMON120, and inserted into pTiB6S3 by recombination and then introduced into petunia and tobacco cells by cocultivating A. tumefaciens cells with protoplast-derived cells. Southern hybridization was used to confirm the presence of the chimeric genes in the transformed plant tissues. Expression of the chimeric genes was determined by the ability of the transformed cells to proliferate on medium containing normally inhibitory levels of kanamycin (50 micrograms/ml) or other aminoglycoside antibiotics. Plant cells transformed by wild-type pTiB6S3 or derivatives carrying the bacterial neomycin phosphotransferase genes with their own promoters failed to grow under these conditions. The significance of these results for plant genetic engineering is discussed.

Aminoglycosides↗
PubMed1983

Dust exposure and mortality in an American chrysotile textile plant.

Three parallel cohort studies of asbestos factory workers were undertaken to investigate the effects of mineral fibre type and industrial process on malignant mesothelioma, respiratory cancer, and asbestosis. This report describes the mortality of a cohort of 2543 men, defined as all those employed for at least a month from 1938 to 1958 in a textile plant in South Carolina in which chrysotile was the only type of asbestos used. Of these, 863 men (34%) had died before 31 December 1977, one from malignant mesothelioma. Twenty one deaths were ascribed to asbestosis and 66 to cancer of the lung. Compared with the number expected from South Carolina, there was an excess of 30 deaths from respiratory cancer (ICD 160-164) in men 20 or more years after first employment (SMR 199.5). In men employed five years or more, no SMRs for this category rose above 300. Individual exposures were estimated (in mpcf X years) from recorded environmental measurements. Life table analyses and "log-rank" (case-control) analyses both showed a steep linear exposure-response that was some 50-fold greater at similar accumulated dust exposures than in Canadian chrysotile mining and milling. These findings agree closely with those from another study in this plant and confirm that mesothelioma is rarely associated with chrysotile exposure. Cigarette smoking habits did not greatly differ between the textile workers and the Canadian miners and millers. The far greater risk of lung cancer in the textile industry, if not attributable to other identified cocarcinogens, may be related to major differences in the size distribution of fibres in the submicroscopic range which are not detected by the usual fibre or particle counting procedures.

Adult↗
PubMed1983

Dust exposure and mortality in an American factory using chrysotile, amosite, and crocidolite in mainly textile manufacture.

This report describes the second in a series of three parallel cohort studies of asbestos factories in South Carolina, Pennsylvania, and Connecticut to assess the effects of mineral fibre type and industrial process on mortality from malignant mesothelioma, respiratory cancer, and asbestosis. In the present plant (in Pennsylvania) mainly chrysotile, with some amosite and a small amount of crocidolite, were used primarily in textile manufacture. Of a cohort of 4137 men comprising all those employed 1938-59 for at least a month, 97% were traced. By the end of 1974, 1400 (35%) had died, 74 from asbestosis and 70 from lung cancer. Mesothelioma was mentioned on the certificate in 14 deaths mostly coded to other causes. All these deaths occurred after 1959, and there were indications that additional cases of mesothelioma may have gone unrecognised, especially before that date. The exposure for each man was estimated in terms of duration and dust concentration in millions of dust particles per cubic foot (mpcf) from available measurements. Analyses were made both by life table and case referent methods. The standardised mortality ratio for respiratory cancer for the whole cohort was 105.0, but the risk rose linearly from 66.9 for men with less than 10 mpcf.y to 416.1 for those with 80 mpcf.y or more. Lines fitted to relative risks derived from SMRs in this and the textile plant studied in South Carolina were almost identical in slope. This was confirmed by case referent analysis. These findings support the conclusion from the South Carolina study that the risk of lung cancer in textile processing is very much greater than in chrysotile production and probably than in the friction products industry. The much greater risk of mesothelioma from exposure to processes in which even quite small quantities of amphiboles were used was also confirmed.

Adult↗
PubMed1982

Mesothelioma and the fiber type in three American asbestos factories - preliminary report.

Preliminary findings are reported from three cohort studies in two asbestos factories (A and B) where chrysotile only was processed and a third (C) where chrysotile, amosite, and crocidolite were used. A total of 10,763 men and 3,118 women has been studied, of whom 97% and 89%, respectively, have been traced and 36% and 16% have died. Death certificates have so far been obtained and coded for 89% of the deaths. The standardized mortality ratios (SMRs) for persons employed less than a year varied greatly between plants. For men employed at least 1 a, an SMR of 129 for all causes and one of 285 for respiratory cancer were found in the chrysotile textile plant (A). The experience of respiratory cancer in this textile plant appears much worse in relation to fiber exposure levels than that observed in chrysotile mines and mills. Other findings in the three plants await clarification by analyses of exposure-response relationships. Among 2,341 deaths from the two chrysotile factories there has been one mesothelioma (0.4 per 1,000); among 1,429 deaths at factory C, which used mixed fibers, there have been 18 (12.6 per 1,000). This finding supports much other evidence that amphiboles are mainly responsible for mesothelioma, whereas chrysotile has little or no mesothelioma-producing potential.

Asbestos↗
PubMed1981

Comparison of multiple puncture liquid tuberculin test with Mantoux test.

Two studies were performed to compare the disposable liquid tuberculin PPD 'Imotest' with the Mantoux test. While there was a tester effect in the first study indicating the need for accurate application of the imotest, the results of the second study showed that the two tests were comparable in selecting truly positive and negative tuberculin reactors. Results were compared both by conventional methods and by a method new to tuberculin testing, the maximum likelihood technique. This method gives a more accurate estimate of false reaction rates. A significant difference was found between reading at 48 and 72 h for both tests. The acceptability and ease of reading of the imotest, with a tuberculin selectivity comparable to the Mantoux method, make it a suitable alternative tuberculin test, especially for screening large populations.

False Negative Reactions↗
PubMed1978

Smoking and health: the association between smoking behaviour, total mortality, and cardiorespiratory disease in west central Scotland.

The relationship of smoking to total mortality and to the prevalence of cardiorespiratory symptoms has been studied in three prospective surveys in west central Scotland in which 18 786 people attended a multiphasic screening examination. The prevalence of respiratory symptoms, and to a lesser extent cardiovascular symptoms, increased with the number of cigarettes smoked, with inhalation, and with a younger age of starting to smoke. A lower prevalence of respiratory symptoms in both sexes was observed in smokers of filter cigarettes than in smokers of plain cigarettes, and in those who smoked cigarettes with lower tar levels, irrespective of whether these were filtered or plain. In general, the relationships found between smoking and mortality were similar to those reported by other workers. Current cigarette smokers had a death rate from all causes which was twice that of those who had never smoked. No difference was found between the mortality rates of smokers of plain and filter cigarettes.

Age Factors↗