Search PubMed⌕ Search

Biomedical subjects

I Andersen

Publications and source records attributed to I Andersen.

At least 91 records · Page 5Linked to original sources
PubMed1980

Variations of nickel in plasma and urine during the work period.

One of the basic problems in monitoring exposure of nickel refining workers has been the unclear correlation between plasma nickel, urine nickel, and airborne nickel during the eight-hour work period or throughout the 24-hour day. In previous studies the authors have demonstrated the value of biological sampling in an occupational health program in the nickel processing industry. Whether a single plasma or single urine sample is an adequate gauge of exposure or whether 24-hour urine specimens or a three-day average plasma level are more accurate indices remained to be determined. The purpose of this paper is to report the results of studies of diurnal variations which affect the significance of single biological samples. In addition, data gathered on the correlation of plasma and urine nickel levels with soluble and insoluble nickel compounds in the atmosphere are presented.

Air Pollutants↗
PubMed1979

Quantitation of proteins by electroimmunoassay using a digitizer connected with a programmable calculator.

A system is described which considerably facilitates the reading and the subsequent conversion of measured values to protein concentrations, when proteins are quantitated by the electroimmunoassay a.m. Laurell (1972). The rocket heights of calibration samples and unknown samples are read by a cursor on a magnetic table (Digitizer, Hewlett Packard) and the values are automatically transferred to a programmable calculator (HP 9830 A, Hewlett Packard). It is programmed to calculate the protein concentration of samples by interpolation on a calibration curve fitted to the best polynomium of second degree by the method of least squares. The results and sequence numbers are automatically printed out from a printer (HP 9866 A, Hewlett, Packard), Reading and calculation of the results from one plate with 5 calibration samples (in duplicate) and 20 unknown samples are completed in less than 2 min. This is 10--15 times faster compared with a manual procedure where a hand-drawn calibration curve is used for interpolation.

Computers↗
PubMed1979

A study of the linkage relations of epidermolysis bullosa dystrophica.

Two large families from the Faroe Islands presenting epidermolysis bullosa of the dystrophic type were subjected to extensive linkage analyses with 22 serological markers. No significant evidence in support of linkage with any of these loci was provided. It was found to be very unlikely that the gene or genes causing the present types of epidermolysis bullosa belong to the EBS1 locus known to be closely linked to the GPT locus.

Alanine Transaminase↗
PubMed1979

Human response to controlled levels of inert dust.

We studied nasal mucous flow, airway resistance, and subjective response in 16 young healthy subjects during 5-hour exposures to 2, 10, and 25 mg of inert dust per m3 in an environmental chamber. The dust was a fully polymerized plastic dust containing carbon black. The number of these particles in room air, expressed as a per cent of the total number of particles was 36, 41, 14, 7, and 2, respectively, for the aerodynamic size ranges less than or equal to 1.8, 1.9 to 5.3, 5.4 to 8.9, 9.0 to 12.4, and greater than or equal to 12.5 micron. No significant changes in nasal mucociliary clearance rate or nasal resistance were observed. At all dust concentrations there was a decrease in 1-sec forced expiratory volume, but not in the forced vital capacity or the forced expiratory flow during the middle half of the forced vital capacity. The nasal penetration fraction of particles was approximately 55 per cent for the smallest particles and 20 per cent for the largest particles. Discomfort was proportional to the concentration of dust, but lagged almost 2 hours behind the changes in dust concentration. The discomfort was never excessive; the main complaints were dryness in the nose and pharynx.

Adult↗
PubMed1979

The effects of moderate heat stress on mental performance.

Moderate heat stress is believed to affect mental performance by lowering levels of arousal. Conscious effort can counteract this effect. In most experiments, raised temperatures are perceived at the start by subjects and can act as a stimulus to exert conscious effort. In practice, temperatures usually rise slowly and may therefore have a more marked effect. Thirty-six male and 36 female 17-year-old subjects in standard cotton uniforms (0.7 clo) were exposed in groups of four in a climate chamber to rising air-temperature conditions typical of occupied classrooms, in the range 20--29 degrees C. The maximum rate of rise was 4 degrees C/h. Each group performed mental work during three successive periods of 50 min with 10-min breaks between. During each break the air temperature was reduced by 3 degrees C. Sentence comprehension was significantly reduced by intermediate levels of heat stress in the third hour. A multiplication task was performed significantly more slowly in the heat by male subjects, showing a minimum at 28 degrees C. Recognition memory showed a maximum at 26 degrees C, decreasing significantly at temperatures below and above, and an independent measure of degree of certainty in recall showed a maximum at 27 degrees C. These findings are in accordance with the hypothesis of reduced arousal in moderate heat stress in the absence of conscious effort.

Adolescent↗