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Biomedical subjects

D Irving

Publications and source records attributed to D Irving.

53 records · Page 3Linked to original sources

Spinal cord limb motor neurons in dystrophia myotonica.

The total numbers of limb motor neurons have been counted in 20 micron sections of the lumbosacral spinal cord obtained a autopsy from 5 control subjects who showed no evidence of neuromuscular disease and from 5 patients with dystrophia myotonica ranging in age from 42 to 64 years. No significant reduction in the total number or distribution of such neurons was found in the cases of myotonic dystrophy and the quantity of lipofuscin present in the cells was similar to that in controls. Glial cell numbers were, however, significantly increased in the cases of dystrophia myotonica and this increase was not due to shortening or "crowding" of the relevant cord segments; in 2 patients with dystrophia myotonica the cell body area of the motor neurons was reduced by comparison with normal controls.

Adult↗

The numbers of limb motor neurons in the human lumbosacral cord throughout life.

Forty-seven spinal cords from subjects between 13 and 95 years of age have been examined; in the majority death occurred suddenly or rapidly from a state of previous good health. The limb motor neurons in the lumbospinal segments have been estimated by counting nucleoli in characeteristic cells in every fifth group of 10 serial sections from the entire lumbosacral cord. No evidence exists of loss of motor neurons up to the age of 60 years, but beyond that age, although individual counts vary considerably, there is increasing evidence of a diminishing motor neuron pupulation; above 60 years, several cases showed motor neuron counts of only 50% of the counts in early adult life or middle age. Cell loss appeared to be uniform throughout all the segments and was unaccompanied by any other striking morphological change.

Adolescent↗

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Demography↗

Urinary total oestrogen values determined by an automated method in normal and abnormal pregnancies.

Urinary total oestrogen values in late pregnancy have been determined by an automated, fluorimetric method based on the Kober reaction and Ittrich extraction. The normal range was obtained from 360 samples from 56 patients. The mean value at 40 weeks gestation was 52.6 mg/24 h and the 95 per cent probability bounds were 29.1 and 95.3 mg/24 h, obtained after initial calculations on logarithm values. "Small for dates" foetuses in good condition at birth were associated with oestrogen values generally below the normal mean. They were usually well discriminated from foetuses that died in the uterus. These were always associated with oestrogen values below or approaching 10 mg/24 h before death except when growth had been normal and death was due to mechanical complications at delivery.

Autoanalysis↗

Longitudinal study of workers in an aluminum smelter.

We conducted a 6-y follow-up study that included workers in an aluminum smelter in British Columbia. Of the original cohort, 951 workers left the industry and 985 workers participated in both studies. Comparison of those who left and those who remained showed that those who left were (1) older, (2) had a slightly higher prevalence of respiratory symptoms, and (3) had lower lung function; this was especially true for workers who were 50 + y of age at the time the initial study was conducted. Analyses were conducted only on 586 male workers who did not change their job location or smoking habits between the initial and the follow-up study. Potroom workers in the "high-exposure" group had a significant reduction in the prevalence of cough, but experienced an increase in the prevalence of wheeze. There was no significant difference in the annual decline in forced expiratory volume in 1 sec and forced vital capacity between the potroom workers and controls. In general, older workers and smokers had a greater decline in lung function compared to younger workers and nonsmokers. Leukocyte count done during the initial study was found to be an independent predictor of longitudinal decline in lung function. The lack of exposure effect on longitudinal decline in lung function could be due to "healthy worker" effect and improvement in the working condition of the smelter.

Adult↗

Reagents for measuring intracellular enzyme activity with flow cytometry.

The line of enzyme substrates described, together with the flow cytometer, bring a simplified method of measuring intracellular enzyme activity to the research laboratory. They are optimized for use in flow cytometry but can also be adapted to other fluorescent detection methods (e.g., spectrofluorometry, fluorescent microscopy, and image analysis) (Figure 5). The large number of enzymes that can be measured with the reagents (currently 37), together with the automation and multiparametric capabilities of flow cytometry, offer many advantages over conventional methods of cell characterization. They also expand the potential of functional assays for studying many normal physiological and disease processes.

Animals↗