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Biomedical subjects

S Nilsson

Publications and source records attributed to S Nilsson.

At least 415 records · Page 23Linked to original sources
PubMed1982

Neuropharmacology of adrenergic neurons in teleost fish.

Although this brief review is based on relatively few types of experiments in few species of teleosts, it is possible to summarize some points of interest regarding the similarities and differences in the mechanisms of adrenergic neurotransmission in fish compared to the higher vertebrates. 1. There is a substantial mixing of cranial autonomic ("parasympathetic") and spinal autonomic ("sympathetic") pathways in the cranial nerves. This close relationship between the two systems and the differences in the nature of the neurons of cranial origin (cholinergic, and non-adrenergic, non-cholinergic) and spinal origin (adrenergic, cholinergic and mixed "polynergic") gives a basis in fish also for a complex pattern of innervation of the various organs. 2. Adrenaline is the major transmitter substance in the adrenergic neurons of most teleosts studied, but there are exceptions within the same species. For instance, in the swimbladder mucosa of the cod, noradrenaline dominates, while adrenaline is the major catecholamine in most other organs innervated by adrenergic neurons. The reasons for the regional differences are not known and further studies of the rate of catecholamine turn-over in the adrenergic neurons of fish are clearly indicated. 3. Adrenoceptors of both the alpha- and the beta-type show great similarities with those of mammals. Some differences in the potencies of certain compounds (e.g., clonidine and methoxamine) exist and receptor binding studies should add valuable information about the adrenoceptors of teleosts. The existence of a subtype of beta-adrenoceptor (beta 2) has been proposed and further work is needed to confirm or deny the applicability of the beta 1/beta 2 adrenoceptor terminology in fish. 4. There appears to be some differences in the mode of action of the so called "indirectly acting amines", such as tyramine, between teleosts and mammals. While the uptake of tyramine into the nerve terminals in mammals appears to take place via the cocaine-sensitive neuronal uptake system which is also responsible for catecholamine uptake (uptake 1), tyramine uptake in cod neurons appears to be via a separate pathway. 5. Presynaptic supersensitivity of the type seen in mammals has also been demonstrated in teleost adrenergic neurons. Both denervation (chemical or surgical) and blockade of the neuronal uptake mechanism by cocaine or desipramine produce this type of supersensitivity, while post-synaptic supersensitivity has so far not been described in teleosts. The effects of removal of the uptake system shows that the uptake process may be as important in teleosts as in mammals in the removal of adrenergic transmitter from the synaptic cleft. 6. In the total picture of adrenergic functions in fish, the circulating catecholamines take a special role...

Adrenergic Fibers↗
PubMed1982

Anti-coagulant and anti-thrombotic effects of some protease inhibitors.

Several synthetic tri-peptide enzyme inhibitors of the general sequence Phe-Pro-Arg were studied in vitro and in vivo. Extent and specificity of inhibition of thrombin were different. The inhibitors exert anti-coagulant effects in vitro. The anti-coagulant effect in vivo was used as a measure of bioavailability and duration of action. The tri-peptide inhibitors are rapidly eliminated from the circulation and produce a decrease in blood pressure. Anti-thrombotic effects were demonstrated in a thrombosis model in rabbits.

Animals↗
PubMed1982

Jogging injuries: an overview.

Middle-aged persons who start physical training have a relatively high incidence of injuries. Most of these injuries are minor, but they often represent an important cause for dropout from training. This article reviews the most common injuries among beginners, with special reference to those arising during running. Most of these are "overuse" or stress injuries. The most important therapeutic principles for both acute injuries and stress injuries are outlined. Finally the most significant preventive measures against injury are discussed.

Ankle Injuries↗
PubMed1982

Treatment of complicated infections of the male genital tract, with emphasis on Chlamydia trachomatis.

Prostatitis and epididymitis, which are the most common complications of urethritis in men below 35 years of age, may be associated with Chlamydia trachomatis infection. Chlamydiae have been isolated from expressed prostatic fluid in men with urethritis complicated by prostatitis and from the epididymis in men with acute epididymitis. Tetracyclines are effective treatment for genital chlamydial infections, including those affecting the accessory genital glands. Two 7-day courses of lymecycline, separated by a 10-day interval, eradicated C. trachomatis from 26 men with prostatitis and genital chlamydial infection. With erythromycin, results of treatment were unsatisfactory. Since acute prostatitis carries a risk of chronic infection, and since epididymitis, in particular, may lead to reduced fertility, prompt antibiotic treatment should be administered to patients with either of these two conditions.

Adult↗
PubMed1982

Medical examinations of and advice to middle-aged persons starting physical training.

Medical screening of all middle-aged persons who want to start physical training is impossible due to practical and economical reasons. These examination should be confined to persons with symptoms from various organ systems especially the cardiovascular system, and to persons who experience these symptoms during training. Recommendations for examination are described briefly. Physical training may improve cardiovascular function and positively influence factors normally associated with the aging process. In order to achieve these effects, training for 30 minutes, three times a week seems to be sufficient. The intensity of training should be high enough to tax approximately 50% of the individual's maximal oxygen consumption. This intensity can be secured by recording the individual's heart rate during the activity, by using the "talk speed" intensity, or by using perceived exertion according to the Borg scale. During the first weeks of training the intensity should be even lower in order to avoid injuries to the musculo-skeletal system.

Aged↗
PubMed1981

Enzyme histochemical studies of human spermatozoa correlated with the spermiogram.

The activities of NADH2-diaphorase, leucine aminopeptidase, and acid phosphatase were studied histochemically in spermatozoa and seminal plasma of 28 ejaculates from 13 men with proven fertility and in 31 ejaculates from 29 men living in infertile marriages. The enzyme activities were correlated with the spermiogram. The NADH2-diaphorase activity was located exclusively in the midpiece of the spermatozoa, while the activities of leucine aminopeptidase and acid phosphatase seemed to be located only on the surface. A positive correlation was found between the NADH2-diaphorase activity and the spermatozoal motility, density, and morphology.

Acid Phosphatase↗
PubMed1981

Activity of dopamine-beta-hydroxylase (DBH) and phenylethanolamine-N-methyl transferase (PNMT) in heart, lung and chromaffin tissue from the Florida spotted gar Lepisosteus platyrhincus (Holostei).

The activities of dopamine-beta-hydroxylase (DBH; E.C. 1.14.17.1) and phenylethanolamine-N-methyl transferase (PNMT; E.C. 2.1.1.10) were estimated in homogenates from the heart, the lung and the posterior cardinal veins from Lepisosteus platyrhincus. Both enzymes could be detected in all three tissues, the activity being highest in the chromaffin tissue of the posterior cardinal veins. The activity of DBH estimated in the present in vitro experiments was about 100-fold higher than the PNMT activity. Preliminary experiments with substrate specificity for the PNMT shows a low (heart) or undetectable (lung and cardinal veins) methylation of phenylethylamine, and the specific PNMT inhibitor SK&F 64139 (1 micro M) lowered the PNMT activity in all three tissues by 55-75%. The presence of PNMT in the adrenergically innervated tissues puts Lepisosteus with the teleosts and the amphibians among vertebrates with capacity for truly adrenergic, as opposed to noradrenergic, transmission.

Animals↗
PubMed1981

On the adrenergic system of ganoid fish: the beluga, Huso huso (chondrostei).

The adrenergic system of the beluga, Huso huso, was studied by glyoxylic acid fluorescence histochemistry, analyses of catecholamine content in various organs and studies of the effects of acetylcholine and adrenaline on isolated strip preparations from blood vessels, spleen, atrium and ventricle. Chromaffin cells were found mainly in the walls of the posterior cardinal veins, and to some extent also in the wall of the celiaco-mesenteric artery. The plasma concentration of adrenaline was high enough to affect the contraction force of the isolated atrial and ventricular strips, thus adding an adrenergic component to a possible cholinergic inhibitory vagal control of the heart. Fluorescence histochemistry revealed no direct adrenergic innervation of the heart, but blood vessels in the heart and elsewhere received a rich supply of adrenergic nerve terminals. Adrenaline contracted the celiaco-mesenteric artery and the spleen, and produced positive inotropic effects on the paced atrial and ventricular strip preparations. Acetylcholine contracted the ventral aorta and the celiaco-mesenteric artery, and reduced the contraction force of paced ventricular and, especially, atrial preparations. It is concluded that the beluga has a well developed adrenergic system consisting of both chromaffin cells and adrenergic neurons with varicose nerve terminals of the type found in the higher vertebrates.

Acetylcholine↗
PubMed1981

Axonal transport and subcellular distribution of dopamine-beta-hydroxylase in the cod, Gadus morhua.

The axonal transport of dopamine-beta-hydroxylase (DBH; E.C. 1.14.17.1) was studied in the splanchnic nerve of the cod in vivo, and the subcellular localization of the same enzyme was studied in the chromaffin tissue from the cod head kidney. The mean rate of axonal transport for cod DBH was 18.6 mm/24 h at 10 degrees C. The mobile fraction was estimated to 22%, giving an absolute rate of transport of 85 mm/24 h at 10 degrees C. Evidence for a retrograde transport of DBH was also obtained, with an accumulation distal to a ligature of 12% of the accumulation proximal to the ligature at 3 days. DBH from the chromaffin tissue appeared to be strongly bound to the adrenergic granules, with only a small amount (ca 4%) recovered in the soluble phase.

Animals↗