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Biomedical subjects

R Andersson

Publications and source records attributed to R Andersson.

At least 343 records · Page 19Linked to original sources

What part does the occupational environment play in the occurrence of accidents? Views of accident victims, their fellow-workers, safety delegates, and enterprise managements.

In a survey of occupational accident cases admitted to Malmö General Hospital during a period in 1974, interviews were carried out with the accident victims, and, at their work places, with their fellow-workers, safety delegates, and management representatives as well. The interviewees were asked to express their views on aspects of the occupation environment, which might have had a bearing on the causes of the accident in question, for instance noise, harmful substances, physical and mental stress and accident risks. The results showed wide variations between the views of the four groups regarding the same environment situation and the actual accident. Often the explanations were rather descriptions of "supernatural" concepts in other words. This means that in this field there is a great need for an objective instrument for the analysis of accidents and their circumstances. There is no such instrument available today and there is a growing need to develop accident research and its methods, as well as of a practical instrument for the safety work. There is also a need for a more qualitative analysis of accidents. To this end we used a model developed by J. Surry (4) and later modified by the Swedish Work Environment Fund (5). A further development of this model is proposed.

Accidents, Occupational↗

Induction of specific immune unresponsiveness with purified mixed leukocyte culture-activated T lymphoblasts as autoimmunogen. II. An analysis of the effects measured at the cellular and serological levels.

T lymphoblasts specific for foreign histocompatibility antigens and purified via mixed leukocyte culture (MLC) and 1 g velocity sedimentation procedures can be used as autoimmunogen to produce specific immunological unresponsiveness in adult animals. This unresponsiveness is positively correlated to the production of autoanti-idiotypic antibodies in the blast immunized animals and no evidence of coexisting alloimmunity was found. We consider this autoanti-idiotypic immunity to be the specific inducing agent of the immune tolerance. The blast immunization procedure will lead to selective reduction in T-cell reactivity against the relevant alloantigens as measured by MLC, cell-mediated lympholysis, or graft-versus-host assays. However, in individual animals, dichtomy in suppression between two T-cell assays could sometimes be observed indicating elimination of only a select group of idiotypic functionally distinct population of T cells in these blast-immunized animals. Attempts to abrogate already immune animals by the autoblast procedure were successful, in part suggesting the use of the present procedure when trying to induce in accelerated reversion of such immunity.

Animals↗

Induction of specific immune unresponsiveness using purified mixed leukocyte culture-activated T lymphoblasts as autoimmunogen. I. Demonstration of general validity as to species and histocompatibility barriers.

Normal immunocompetent T lymphocytes can be induced into specific proliferation if confronted with the relevant alloantigen in vitro. Such mixed leuko-cyteculture-activated T lymphoblasts carring idiotypic receptors on their surface can be purified using velocity sedimentation and serve as immunogen if administered in adjuvant to the autologous host. Autoblast immunization can be shown to lead to specific, long-lasting unresponsiveness against the relevant alloantigens, while leaving reactivity against third-party antigens intact. When tested as to general validity, it could be shown to function in all species analyzed (mouse, rat, and guinea pig) as well as across both major and minor histocompatibility barriers. No negative side effects have been noted so far. It would thus seem clear that autoblast immunization using the above described scheme may serve as a general tool in inducing long-lasting, specific unresponsiveness in any species and across any histocompatibility barrier.

Animals↗

Peripheral circulation, particularly heat regulation reactions, in patients with amyloidosis and polyneuropathy.

As patients with amyloidosis and polyneuropathy often have signs and symptoms of circulatory disturbances in the extremities, especially the legs, we have examined such patients and controls with oscillometry and digital pulse plethysmography in order to estimate the occurrence of any arterial circulatory insufficiency. No signs of significant obliterative arterial changes were found. Skin temperature was also determined in fingers and toes during body-cooling and at subsequent indirect heating. At low environmental temperature the skin temperature was higher in patients than in controls. In a few patients there was almost no decrease in skin temperature, despite a long period of cooling and a low rectal temperature. Indirect heating elicited a marked increase in the skin temperature of the toes and fingers of the controls. In most patients this reaction was completely absent in the toes and absent or reduced in the fingers. These deviations can be explained by nerve damage caused by amyloid deposition in the nerves. Amyloid deposits in the wall of small blood vessels may be an additional factor. Maximum blood flow in the anterior tibial muscle after combined ischemia and exercise, investigated with radioactive xenon, was reduced in half of the patients.

Adult↗

Mechanical and metabolic effects of beta-receptor stimulators, the C-terminal octapeptide of cholecystokinin, and prostaglandin E2 on the isolated, depolarized sphincter of Oddi.

Similar to their actions on normally polarized, isolated sphincter of Oddi, the beta-receptor stimulators isoprenaline and tebutaline, and prostaglandin E2 produced relaxation of the depolarized preparation. The relaxation was accompained by an increase in the intracellular content of cyclic AMP. In contrast to its relaxing effect on normally polarized sphincter preparations, the C-terminal octapeptide of cholecystokinin (C8-CCK) contracted or had no effect on the depolarized sphincter. There was no change or a small decrease in the content of cyclic AMP in the muscle. It is suggested that the relaxing effects of beta-receptor stimulators and prostaglandin E2 on isolated sphinceter of Oddi, and the simultaneous increase in cyclic AMP-content are mediated processes independent of the electrical acitivty of the membrane. However, C8-CCK mediated relaxation and increase in cyclic AMP is dependent on the membrane potential.

Ampulla of Vater↗

Grouping of patients with hyperparathyroidism by clinical signs, correlated to some biochemical findings.

Serum parathormone (S-PTH), total and free fractions of serum calcium (Cat and Caf), urinary excretion of cyclic 3',5'-adenosine monophosphate (cAMPu), serum phosphate and serum magnesium were analysed in 68 patients with hyperparathyroidism verified by operation and PAD. The diagnostic significance of the analyses was examined. It was shown that Caf was consistently above normal even in patients in whom the other tests were normal. The best diagnostic sensitivity was thus found for Caf followed by Cat, S-PTH and cAMPu. The results of these tests were generally correlated to each other except in patients with impaired renal function in whom S-PTH increased out of porportion to the other tests. Cat and Caf were significantly correlated to each other. However, Caf was pathologic even when Cat was normal. It is concluded that for hypercalcemic patients Cat and Caf are the most reliable tests. S-PTH is elevated only in some hypercalcemic patients. In normocalcemic patients all tests except Caf show normal values.

Adult↗