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Biomedical subjects

S J Simpson

Publications and source records attributed to S J Simpson.

61 records · Page 4Linked to original sources
PubMed1982

Comparison of peak expiratory flow rate and forced expiratory volume in one second in histamine challenge studies in children.

The difficulty in performing FEV1 in young children prompted us to assess whether PEFR could be used to measure the response to inhaled histamine. In 123 children with recurrent respiratory symptoms we found a highly significant correlation (r = 0.83, P less than 0.001) between the percentage fall from base-line of FEV1 and PEFR. We also performed histamine challenge tests using PEFR alone on 56 children too young to manage spirometry and found our procedure reliable. PEFR is an adequate measurement in histamine provocation studies and can be used interchangeably with FEV1. The criterion for a positive test is a 20% fall in either PEFR or FEV1.

Adolescent↗
PubMed1981

Bronchial reactivity in cystic fibrosis with normal pulmonary function.

We studied 20 children with cystic fibrosis who had relatively normal pulmonary function (forced expiratory volume greater than or equal to 70% of predicted) to determine whether demonstration of heightened bronchial reactivity in this group reflects coexistent asthma. Using a standardized histamine provocation, we found that eight (40%) had a positive response. These responders were significantly younger than the nonresponders, had a greater incidence of clinical asthma, and all were atopic on skin testing. However, they had a significantly higher ratio of residual volume to total lung capacity than the nonresponders. Although as a group they were less sensitive to histamine than children with asthma, four of the responders with cystic fibrosis had histamine sensitivity similar to a group of asthmatic patients. We concluded that, in the presence of mild lung disease, the demonstration of heightened bronchial reactivity in children with cystic fibrosis may provide confirmatory evidence of coexistent asthma, particularly if the children are highly sensitive to histamine.

Adolescent↗
PubMed1981

The identification of Y chromosome translocations following Distamycin A treatment.

Pretreatment of PHA-stimulated lymphocyte cultures from normal males with 100 micrograms/ml Distamycin A for the final 24 h of incubation led to a striking decondensation of the heterochromatic portion of the long arm of the Y chromosome. The despiralized region of Yq maintained its fluorescent properties in this altered morphologic state. Two cases of Y chromosome translocation (Y/22 and Y/X) were identified with this technique. A review of the literature revealed 62 similar cases in which the phenotypic-karyotypic correlations were instrumental in the prenatal counseling of the family with the Y/22 translocation.

Chromosome Banding↗
PubMed1981

Specificity of bleomycin-induced cytotoxic effects on ataxia telangiectasia lymphoid cell lines.

Bleomycin exposure evoked a specific sensitivity in five ataxia telangiectasia (AT) long-term lymphoblastoid cell lines when compared to lines derived from four normal individuals or three patients with xeroderma pigmentosum. At all concentrations tested or after each treatment regimen, statistically significant differences in viability and cytogenetic damage were obvious, with the AT cell lines demonstrating reduced survival and increased chromosomal breakage. However, similar differences were not observed following treatment of all cell lines with mitomycin C. The normal and xeroderma pigmentosum cells appear capable of overcoming the effects of bleomycin during a 48- or 72-hr recovery period while the AT cell lines could not. This specific response to bleomycin constitutes the first demonstration of increased chromosome breakage in vitro in long-term AT lymphoblastoid cell lines.

Ataxia Telangiectasia↗
PubMed1980

Allergen skin-prick testing in asthmatic children.

Allergen skin-prick tests to the common airborne allergens were performed on 534 children with asthma. A positive reaction to one or more allergens was observed in 81%, and the prevalence increased with age. The specific allergen reactions were characteristic with a high prevalence of reactions to house-dust mite (Dermatophagoides pteronyssinus) (88%), house dust (79%, and cat fur (62%), and a low prevalence of grass-pollen reactions (12% to 25%). We found that the diagnosis of atopy could be made in virtually all (96%) of these children by using only three allergens: D. pteronyssinus, cat fur, and rye grass.

Adolescent↗
PubMed1980

Growth kinetics of ataxia telangiectasia lymphoblastoid cells. Evidence for a prolonged S period.

Growth rates were investigated in long-term lymphoblastoid cell lines derived from normal individuals and patients with ataxia telangiectasia (ATR). By a cell doubling method, sister chromatid exchanges, and autoradiography, the ATR cells showed a significantly longer total generation time. Autoradiography demonstrated that the difference in cell cycle was due to a specific lengthening of the S period in the ATR lymphoblasts.

Adult↗