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Biomedical subjects

J Nilsson

Publications and source records attributed to J Nilsson.

At least 325 records · Page 18Linked to original sources
PubMed1982

Trunk muscle strength during constant velocity movements.

A new apparatus has been designed for standardized measurements of the strength of human trunk muscles utilizing the isokinetic (constant movement velocity) technique (Cybex). It is possible to measure the produced torque during maximal voluntary isometric and isokinetic contractions in the whole range of motion during flexion, extension and lateral flexion of the trunk. Effects of gravity are eliminated since the movements are performed in the horizontal plane. Torque can be measured around different centres of rotation of the body. With this experimental set-up the strength of the trunk muscles has been characterized in a group of 14 normal male subjects (18-31 yrs). The torque produced by the trunk muscles varied with movement velocity and trunk position in the arc of motion. Peak torque occurred in a position where the muscles involved were stretched. The strength of the trunk extensors exceeded that of the flexors, but the degree (ratio) varied with trunk position. The relative contribution of the hip muscles to the total torque produced with the centre of rotation at the hip joint was larger for flexors than for extensors and varied with velocity and position. It is concluded that the present technique is useful to characterize the human trunk muscles.

Adolescent↗
PubMed1981

Preoperative embolization of renal tumours using balloon catheters.

Preoperative embolization was used in a series of 13 patients for reducing the bleeding during operation of even very large renal carcinomas. During and after embolization pain occurred which necessitated treatment. Balloon catheter embolization was used which excludes the risk of reflux of embolizing material to the aorta. It caused none or only minor injury to the renal arterial wall. No serious complication occurred.

Adult↗
PubMed1979

Electron microscopic and cytochemical studies of rat aorta. Intracellular vesicles containing elastin- and collagen-like material.

Small, rounded vesicles with a dense core of amorphous material were observed in all cell types in the young rat aorta, that is, endothelial cells, smooth muscle cells and fibroblasts. They were particularly numerous in the Golgi complex but were also found in the cell periphery. The content of the vesicles had staining characteristics identical to those of elastin. Material of the same type was also found in cisternae on the maturing side of the dictyosomes and in vesicles budding from them. Reaction product for thiamine pyrophosphatase was present in both these structures, indicating that the Golgi complex is responsible for the formation of the dense-cored vesicles. This was further supported by the absence of reaction product for acid phosphatase in the cisternae and in the vesicles. Moreover, no uptake of exogenous markers was noted in the latter. On the basis of these findings it is suggested that the dense-cored vesicles have a secretory function and contain precursors of elastin. Elongated vesicles or profiles containing collagen fibrils were observed in smooth muscle cells and fibroblasts. In the cell periphery, these vesicles were often found to communicate with the extracellular space. Further inside the cells, they showed a close spatial relationship to the Golgi complex. Neither thiamine pyrophosphatase nor acid phosphatase activity was demonstrated in the elongated vesicles. Like the plasma membrane, their limiting membrane was positively stained for alkaline phosphatase. On the basis of these findings and the absence of uptake of exogenous markers in them, it is suggested that the elongated vesicles represent a means for collagen secretion in the growing aortic wall. The Golgi complex is believed to be involved in the transfer of collagen to these vesicles.

Animals↗
PubMed1978

Intra-abdominal pressure changes during natural movements in man.

The weight of the upper part of the trunk is partially transmitted to the pelvis via the vertebral column. If the muscle walls around the abdominal cavity are contracted, a high pressure can be generated within the cavity (greater than 200 mmHg). The abdominal space can them transmit part of weight to, e.g., the upper part of the body, Intra-abdominal pressure recordings have been performed during locomotion and other natural movements with intragastric pressure recordings. With each step, there is a phasic variation in pressure, with its peak coinciding with that of the peak vertical force exerted by the leg against the ground. The peak values increase progressively with the speed of walking/running up to a mean of 38 mmHg and with trough values of 16 mmHg. The phasic variations with each step is due to a phasic activation of the abdominal muscles, with an EMG activity starting 50 ms or more before foot contact. If an extra load is put on the back, the posture changes and at the highest speed of running the pressure values are significantly higher than without this additional load. After a jump down from a moderate height of 0.4 m, the average increase is 89 mmHg and can often exceed 100 mmHg. These pressure changes are large and will presumably act to unload the spine under the prevailing biomechanical conditions and, in addition, there will no doubt be an effect on the circulatory system.

Abdomen↗
PubMed1977

Fatigue and EMG of repeated fast voluntary contractions in man.

A fatigue test consisting of repeated fast maximal contractions of the left quadriceps muscle in an isokinetic apparatus was performed by 12 healthy male subjects (19-25 yrs). EMG signals recorded from the surface of the left vastus lateralis muscle, from which also biopsies were obtained for muscle fibre classification. Only minor changes were observed in the EMG variables despite a decrease in muscle strength performance, in terms of peak torque, work and power to about 50% of initial values after 100 contractions. The concomitantly obtained positive correlation between the increase in EMG/torque ratio and the individual percentage of fast twitch (FT) muscle fibres indicated that local factors in the muscle, primarily in FT fibres, were causing the development of fatigue during repeated dynamic contractions with high power outputs.

Adult↗
PubMed1975

Urethrocystography during and after transurethral prostatic resection.

Ten men were subjected to transurethral electroresection because of prostatic adenoma. All were examined with urethrocystography on 3 occasions, viz. at the end of operation, 4-7 days later and after a further 2-3 months. Peroperative examination for residual adenoma appeared to be of little value, while examination a few days after the operation revealed residual adenomas in 2 cases and possibly also in a third. The cavity left after the operation had the same size at the peroperative and the first postoperative examination, though its outline was sometimes smoother at the latter. During urination the cavity invariably increased in size. At the second postoperative examination the operation cavity was clearly smaller and its outline smoother in 9 of 10 cases. The cavity still expanded during micturition. No passage of contrast medium to the veins was ever demonstrable. At the peroperative examination the contrast medium was not injected under any substantial pressure and the cavity was not exposed to pressure by micturition. Even at the first postoperative examination, when the operation cavity was exposed to pressure by urination, the veins that had been opened at operation had closed so effectively that no contrast medium passed outside the prostatic capsule. Urethrocystography in association with TUR of prostatic adenoma is of interest to the urological surgeon. It provides him with a possibility to check his work very carefully.

Aged↗