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Biomedical subjects

O Korhonen

Publications and source records attributed to O Korhonen.

72 records · Page 4Linked to original sources
PubMed1979

Hand grip forces during chain saw operation and vibration white finger in lumberjacks.

The hand grip forces at the front and rear handles of a chain saw were measured during work, in 89 professional lumberjacks. The symptoms caused by vibration to the upper limbs were compared with the hand grip force (HGF) during work. To allow better comparison between subjects we used the ratio of hand grip force (HGF) to the maximal voluntary compression force (MVC), HGF/MVC expressed as a percentage. The mean HGF during sawing varied from 5 to 12 N in all subjects. The variation in HGF was greater at the front handle than at the rear handle, during sawing. The lumberjacks who had vibration-induced white fingers (VWF), had a higher HGF/MVC in both hands than the lumberjacks without VWF. Those lumberjacks affected by VWF used over 12% of their MVC at work. Subjects without HGF/MVC ratio. The lumberjacks with and without numbness in their hands had equal HGF/MVC ratios.

Adolescent↗
PubMed1978

Amount and distribution of welding fume lung contaminants among arc welders.

The amount and distribution of the welding fume lung contaminants was measured in 44 arc welders from two shipyards. The measurement was made from the determination of the permanent field after the subject was magnetized in a low external magnetic field, the values being used for the calculation of the amount of contaminants in the lungs. Less than 4 mg of dust was found in the lungs of nonexposed controls. In the shipyard welder's lungs, after two years of exposure, on the average 7 mg (range 4-15) of welding dust was observed. After a continuous exposure of about 18 years the amounts were 200 mg (range 30-1,500) in shipyard A and 700 mg (150-2,000) in shipyard B, respectively. On the basis of data obtained from retired welders, the clearance rate of 45% in welders from shipyard A and 18% in shipyard B were calculated, the latter figure being probably more accurate. The distribution of contaminants was 52% in the right and 48% in the left lung. The radiological findings correlated well with the amounts of welding fume contaminants measured with the magnetic method.

Adolescent↗
PubMed1977

Age and sex as determinants of the relative aerobic strain of nonmotorized mail delivery.

The relative aerobic strain (RAS) of nonmotorized mail delivery was assessed in 54 Finnish mail carriers who represented both sexes, the entire workage range and both downtown and suburban delivery districts. The mean RAS of the entire delivery time was 55% of the maximal oxygen uptake (ml/kg-min). It was higher for women than for men, and higher for suburban than for downtown delivery. The RAS tended to increase systematically with age after the age of 50. The work strain of mail carriers of over 50 years of age, especially of older women carriers in suburban areas, was concluded to be high enough to lead to possible excessive strain on the workers.

Adult↗
PubMed1976

Transmission of vibration in the hand-arm system with special reference to changes in compression force and acceleration.

The transmission of longitudinal vibration in the hand-arm system of five subjects was investigated. Altogether 405 individual tests were made. Vibration was measured with an accelerometer (weight 0.4 g) fixed in turn to the wrist, the elbow, and the upper arm by means of a supporting device (weight 34 g). A handle with strain gauges attached was used to study the effect of compression force (10, 20 and 40 N) and constant acceleration (1, 3 and 10 g) on the transmission of vibration at frequencies from 20 to 630 Hz. In the curves recorded, sharp dips appeared which were evidently caused by resonances from the soft tissues of the hand. However in the hand-arm system no common resonance frequency was observed that would harmfully affect the health of workers. Vibration in the hand-arm system was attenuated at an average of 3 dB per octave at the frequencies between 20 and 100 Hz. Between 100 and 630 Hz the attenuation was about 6 dB per octave in the wrist and 10 dB per octave in the elbow and upper arm. At the frequency of 630 Hz the attenuation was hence about 35 dB in the wrist and about 45 DB in the elbow. The attenuation of vibration in the elbow joint was 2 to 4 dB at all frequencies. The hand-arm system appears to be linear at the acceleration range considered; the increase in handle vibration by, e.g., 10 dB also increased vibration in the hand by 10 dB. When the grip strength was increased fourfold, i.e., 12 dB, vibration increased only 3 to 5 dB in the hand-arm system. Thus changing the weight of a vibrating tool does not reduce vibration enough. Therefore attempts to reduce vibration should concentrate on the mechanical parts of the engines.

Acceleration↗
PubMed1975

Arterial to end-tidal CO2 difference in respiratory disease.

The difference in CO2 tension between arterial blood and end-tidal alveolar gas (a-end-tidal)DCO2 was found to correlate fairly well with the VD/VT ratio in 13 healthy subjects and 50 patients with pulmonary diseases (r = 0.74), and to discriminate between healthy subjects and patient groups at least as effectively as did the VD/VT ratio. An increase in breathing frequency from 8 to 32/min, without simultaneous change in alveolar ventilation, was associated with a mean increase in (a-end-tidal) DCO2 of several mmHg in both the healthy subjects and the patient groups. It is concluded that measurement of (a-end-tidal)DCO2 seems to be a clinically useful alternative to measurement of VD/VT ratio for evaluation of the wasted ventilation component, provided that the effect of the breathing frequency on (a-end-tidal) DCO2 is taken into account.

Adult↗
PubMed1970

Exercise asthma and disodium cromoglycate.

Exercise-induced asthma (defined as a fall in PEF of at least 25% of the pre-exercise value) was studied in adult patients with uncomplicated asthma. This was found to occur in 22 out of 52 patients. Pre-exercise inhalation of disodium cromoglycate reduced the mean fall in PEF after maximal exercise from 50% of the pre-exercise value to 23% (open assessment in 11 cases). After submaximal exercise for eight minutes the reduction was from 18% to 10% (double-blind crossover study in 28 cases). It is concluded that disodium cromoglycate partly inhibits the increase of airways resistance after exercise in asthmatic patients.

Adolescent↗