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Biomedical subjects

B Stigsby

Publications and source records attributed to B Stigsby.

At least 55 records · Page 3Linked to original sources

Reaction time of industrial workers exposed to organic solvents: relationship to degree of exposure and psychological performance.

Auditory reaction time (RT) was examined on a day free from work and on a working day in 54 workers exposed to organic solvents and in 28 unexposed workers. Medical and occupational history was recorded and neurological examination and psychological testing carried out to establish quantitative parameters of exposure and cerebral function. There was a wider 95% range of the RT in the exposed group compared to the control group on the working day and a tendency in the same direction on the day free from work. There was no difference in the means of the RT, or within the groups between the examinations on the two days. The increased RT 95% range is interpreted as indicating an impaired ability in the exposed workers to maintain their attention during the experimental period, owing to chronic exposure of organic solvents. RT measurements did not correlate with exposure or psychological performance. RT would seem to be a means of measuring subclinical effects of exposure to organic solvents.

Adult↗

Electroencephalographic findings during mantra meditation (transcendental meditation). A controlled, quantitative study of experienced meditators.

The EEGs of 13 experienced practitioners of transcendental meditation (TM) were recorded for 5 min preceding TM, during 20 min of TM and until 5 min after, as well as during closed-eyed wakefulness, drowsiness, sleep onset and sleep. Thirteen healthy volunteers matched for age served as control subjects. Computer period-amplitude analysis of F3-C3, T3-T5, P3-O1, F4-C4 and P4-O2 epochs of 50--100 sec duration resulted in a frequency and amplitude spectrum (0.5--28.6 c/sec), and the mean frequency and the mean voltage of each EEG lead. The EEG frequency spectra constituted a continuum with increasing theta and delta activity and decreasing alpha activity as the participants tended to fall asleep. The frequency spectrum during TM corresponded to a spectrum situated between that of wakefulness and drowsiness and remained virtually unchanged during the 20 min of meditation. The EEG mean frequency of the TM group was about 1 c/sec slower than that of the control group. Intra- or interhemispheric differences between quantities of EEG activity remained stable during TM, nor did we observe any theta bursts. There was no consistent EEG patter associated with a successful or unsuccessful meditation, nor did the EEGs of two meditators who stated they had felt drowsy during TM show a different pattern.

Adult↗

Computerized hot-wire anemometry--principles of calculation.

Principles of calculation of respiratory parameters based on a hot-wire anemometer with special reference to computer monitoring were evaluated. Flow-rate, gas-pressure, and flow-direction signals were recorded simultaneously on magnetic tape. Subsequent quantitative analyses were performed on a general purpose digital minicomputer. An analysis epoch of 256 s was selected from the 3 channels. After identification of one cycle baseline values of flow-rate and pressure were determined. Different time-lags in one respiratory cycle (inspiratory time, pause time and expiratory time) could be determined. Inspiratory and expiratory volumes were obtained by integration. Peak of the thoracic cage and the lungs were calculated using the above mentioned parameters. Finally, the respiratory frequency was calculated.

Airway Resistance↗

Electroencephalographic changes in the dominant hemisphere during memorizing and reasoning.

The EEG was recorded with bipolar technique in ten normal subjects in the frontal, temporal and occipital regions of the dominant hemisphere in four situations: (1) during an auditory memory test, (2) during 'auditory rest' (listening to white noise), (3) during a visual reasoning test and (4) during 'visual rest' (watching a black dot on a white screen). Computer analysis of the EEG was made by (a) an on-line automatic EEG analyser yielding measures of mean power, mean frequency and frequency spread (complexity) and (b) an off-line period-amplitude (P-A) analysis, which gave per cent activity time and mean voltage in 21 frequency bands. As compared to auditory rest the auditory memory test gave an amplitude increase frontally in the alpha, theta, and delta bands. During the visual reasoning test there was in addition an amplitude increase in the alpha band in the temporal region. During the auditory test a tendency to a decrease of the alpha activity was seen in all three regions but this decrease occurred only occipitally during the visual test. The two types of mental activity thus induced two patterns of regional EEG changes. These showed principal similarities to regional cerebral blood flow patterns which have been recorded during visual and auditory tests of about the same types as those used in the present study.

Auditory Perception↗

Effect of portal-systemic anastomosis on renal haemodynamics in cirrhosis.

In 12 patients with portal hypertension and repeated bleedings from oesophageal varices the central haemodynamics, portal pressure, and mean renal blood flow (RBF) were investigated immediately before and two to seven months after portal-systemic shunt. Cardiac output increased significantly, whereas arterial pressure was unchanged after operation. RBF, which was initially less than in controls, did not change. As portal pressure decreased significantly, a direct portal-renal, neural, or humoral reflex mechanism does not explain the subnormal RBF in cirrhosis. As plasma volume was large and unchanged after operation a "diminished circulating plasma volume" is an unlikely explanation. Therefore, on the basis of the present observations, previously postulated causes of renal hypoperfusion in cirrhosis need revision.

Adult↗

Combined oral isoprinosine-intraventricular alpha-interferon therapy for subacute sclerosing panencephalitis.

Eighteen patients, 16 boys and 2 girls, aged 5-14 years, with subacute sclerosing panencephalitis (SSPE) were treated with oral isoprinosine (100 mg/kg/day) and intraventricular alpha-interferon 2b (Intron A, Schering Corp.), starting at 500,000 U twice a week and later increasing to 3 million U biweekly. Minimal follow-up of living patients is 12 months; maximal 40 months. On the basis of the Neurological Disability Index (NDI) scores and staging, 8 have treatment-induced remissions (3 improved, 5 arrested), 4 are worse and 6 died. This 44% (8/18) rate of remission/improvement compares well with the 9% (1/11) remission in historical controls in the same institution (p = < 0.05) and 5% spontaneous remission in the literature. Combined oral isoprinosine-intraventricular alpha-interferon appears to be an effective treatment for SSPE.

Administration, Oral↗