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Biomedical subjects

H Linderholm

Publications and source records attributed to H Linderholm.

At least 37 records · Page 2Linked to original sources
PubMed1985

Arsenic exposure to smelter workers. Clinical and neurophysiological studies.

Forty-seven copper smelter workers, exposed to airborne arsenic for 8-40 years, were examined clinically with electromyography, and the motor and sensory conduction velocities in their arms and legs were determined. Fifty age-matched industrial workers not exposed to arsenic formed a reference group. The level of arsenic in the air at the smeltery was estimated to be below 500 micrograms/m3 before 1975 and approximately 50 micrograms/m3 thereafter. Urine analyses of arsenic showed a mean value of 71 micrograms/l (1 mumol/l) in the exposed group; this value is lower than that found in earlier studies reporting clinically detectable neuropathy. Only minor neurological and electromyographic abnormalities were found. A slightly reduced nerve conduction velocity in two or more peripheral nerves was more common among the arsenic workers than the referents, and a statistically significant correlation between cumulative exposure to arsenic and reduced nerve conduction velocity in three peripheral motor nerves was found. This occurrence was interpreted as a sign of slight subclinical neuropathy. In conclusion the risk of clinically significant neuropathy is small when exposure is kept below 50 micrograms/m3 in workroom air. The subclinical findings may be of interest in relation to the prevention of early adverse health effects from arsenic exposure.

Adult↗
PubMed1983

Restrictive ventilatory dysfunction in stroke: its relation to locomotor function.

Static and dynamic lung volumes, maximum respiratory pressures and lung compliance and resistance were registered in 54 subjects with hemiplegia or hemiparesis after stroke. These measures of ventilatory function were related to the degree of motor impairment and to the interval between stroke and investigation. In general ventilatory function, particularly parameters depending upon expiratory force, was restricted. This was most pronounced in subjects with severe hemiplegia while those with hemiparesis had only small changes. Since dynamic lung volumes (corrected for volume loss), lung compliance and resistance were all normal, it is evident that intrinsic lung function was unaffected. Inspiratory capacity - but no other measured variables of respiratory function - was lower six months after the stroke than earlier. It is suggested that expiratory muscle dys-coordination and weakness caused expiratory dysfunction while the less pronounced inspiratory restriction may be caused by muscular dysfunction and, as time goes by, by rib cage contracture.

Adult↗
PubMed1983

Artificial respiration by phrenic nerve stimulation (diaphragm pacing) in patients with cervical cord and brain stem lesions.

In patients who are dependent upon respirators because of paralysis of respiratory muscles, pacemakers for electrical stimulation of the phrenic nerves, leading to contractions of the diaphragm, are available. We have implanted such diaphragm pacers in ten selected patients with partial or total respiratory insufficiency of central nervous origin. Preoperatively, transcutaneous phrenic nerve stimulation in the neck was undertaken with simultaneous fluoroscopy of the diaphragm and quantitative studies of ventilation and blood gases. Phrenic nerve stimulators were implanted bilaterally in eight and unilaterally in two patients. One patient died 3 weeks postoperatively from pneumonia, the remaining patients are entirely independent of respirator at a mean follow-up time of 20 months. Postoperative studies showed sufficient ventilation with diaphragm pacing in both sitting and recumbent body position. Their quality of life has improved. They still require permanent supervision and help with activities of daily life but all except one live in their homes. They can talk and some of them even attend school.

Adolescent↗
PubMed1981

Some factors of significance for respiratory gas exchange in muscle tissue. A mathematical analysis of a capillary model.

Morphological dimensions of the Krogh cylinder capillary model were calculated by mathematical simulation of respiratory gas exchange and blood flow in muscle tissue, using experimentally determined values for oxygen consumption (n'O2), blood flow (Q'), a-V O2 difference (a-v O2D) and pressure difference over the capillary (delta P), for resting and exercise conditions up to maximum performance. In the resting state a capillary radius, r1, of 3.5 (3-5) microgram a capillary density (CD) of 35 (30-90) capillaries/mm2 and a capillary length (L) of 900 (400-1000) microgram can satisfy experimentally determined values of the physiological variables. During muscular activity a maintained r1 and L with an increased CD allows higher n'O2. An increase in capillaries to about 600/mm2 can allow an n'O2 uptake 30 times the resting value (maximum performance). This increase cannot be achieved by an increase only in the r1. A shift to the right in the O2Hb dissociation curve during exercise has only a small effect on the O2 delivering capacity of the model, as has an increase in the diffusion constant for O2 in tissue. It is remarkable how limited a range of morphological dimensions, particularly of r1, is compatible with the known range of values for n'O2, O', a-v O2D and delta P, at rest and particularly during maximum performance of the muscle.

Capillary Permeability↗
PubMed1979

Reaction to cold of patients with coronary insufficiency.

Twenty six patients with angina pectoris and coronary insufficiency as judged by an exercise ECG test were examined. About half of the patients had more pronounced ECG changes in a cold room at -15 degrees C than at room temperature. They worked less, their subjective rating of exertion during exercise was higher and the heart performed less work, expressed as the heart rate blood pressure product. The other half of the patients was not much influenced by cold. During an exercise test in the supine position almost all patients got more pronounced ECG changes, worked less and the heart performed less work than in the sitting position. It is suggested that cold exposure as well as a supine body position may to a considerable part exert their effect, i.e. lower the anginal threshold and increase ECG changes, by increasing the central blood volume and the diastolic volume of the left heart and thus ceteres paribus the myocardial oxygen consumption.

Adult↗
PubMed1978

Prediction of spirometric values in patients with scoliosis.

The prediction of normal spirometric values requires a measure of the non-deformed body height of scoliotic patients. The arm-span method has been used for estimating the non-deformed body height in spite of the fact that opinions about the normal relationships between body height and arm span differ. In order to minimize the error of estimation of non-deformed body height, the normal relationships between body height and arm span were determined for 91 males and for 118 females of ordinary body stature, varying age (5-78 years), and Swedish origin. The body-height/arm-span relationships were described by linear regression equations taking age into account. The results indicate significant sex and age differences in the arm-span/height ratio. Multiple regression equations including arm span and age as regressors were used to calculate the non-deformed body height in scoliotic patients. The arm-span method was compared with the method using the degree of lateral curvature of the spine for calculation of non-deformed body height of scoliotic subjects. The arm-span method resulted in a correction of body height and predicted spirometric values that agreed closely with those obtained by the method using the degree of curvature of the spine. The two methods may be used alternatively. In accordance with earlier reports, the predicted spirometric values were underestimated when the measured body height was used.

Adolescent↗
PubMed1976

Effect of the Milwaukee brace on vital and ventilatory capacity of scoliotic patients.

The vital capacity (VC) and the maximal voluntary ventilation (MVV) were studied in 29 patients with scoliosis (predominantly idiopathic). The results obtained confirmed earlier observations that scoliotic patients have decreased VC and MVV. The immediate effect of the application of the Milwaukee brace was a slight though statistically significant decrease in MV, whereas there was no significant effect on VC. Treatment with the Milwaukee brace for a mean period of 15 months did not appreciably influence the VC or MVV, as a percentage of the predicted normal values of the patients, when measured without the brace applied.

Adolescent↗
PubMed1975

Intraosseous hypertension and pain in the knee.

The intraosseous pressure in the femur and tibia near the knee and in the internal saphenous vein at knee level was measured in fifty-three patients with suspected knee lesions. There were four groups: with and without degenerative osteoarthritis and with and without aching rest pain of the knee region. Low intraosseous pressures were found in patients with neither osteoarthritis nor rest pain, and in half the patients with osteoarthritis but without rest pain. Low pressures were found in the tibia, but very high intraosseous pressures were found in the femur in most patients with osteoarthritis and rest pain. Patients with no osteoarthritis but with rest pain mostly had high pressures in both the tibia and the femur.

Adolescent↗