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Biomedical subjects

K Andersson

Publications and source records attributed to K Andersson.

At least 343 records · Page 19Linked to original sources

Catecholamine turnover changes in hypothalamus and dorsal midline area of the caudal medulla oblongata of spontaneously hypertensive rats.

The central noradrenaline (NA) and adrenaline (A) turnover in 15--16-week-old stroke prone, spontaneously hypertensive (sp-SH) female rats in an advanced stage of hypertension was found to differ from that of normotensive Wistar-Kyoto (WKy) control rats. The catecholamine (CA) levels were measured after inhibition of dopamine-beta-hydroxylase (DBH) or phenylethanolamine-N-methyltransferase (PNMT). in the hypertensive rats the dopamine (DA) and NA levels and the NA turnover were reduced in the hypothalamus, while in the dorsal part of the caudal medulla oblongata NA levels and A turnover were reduced. Changes in hypothalamic DA and NA mechanisms and in A mechanisms in medulla oblongata may therefore be of importance in the blood pressure regulation of sp-SH rats.

Animals↗

A cohort study on mortality among dynamite workers.

Exposure to nitroglycerine and nitroglycol in the explosives industry is suspected of having caused isolated cases of sudden death. There have also been suggestions of an increased risk of chronic cardio-cerebrovascular diseases among dynamite workers. This study examines the mortality experience of a cohort of male workers from a small Swedish dynamite industry. Cause-, sex-, age-, and calendar-year-specific national incidence rates were used to calculate the expected number of deaths in a group of individuals with exposure to the dynamite manufacturing process and in an unexposed group from the same industry. During the period 1965-77, nine deaths from cardiocerebrovascular diseases were observed, versus 4.5 expected (p less than 0.05), among men with at least one year of exposure to dynamite and 20 years of induction-latency time. The unexposed group had a mortality pattern in good agreement with the national average. Exposure occurred by inhalation as well as through the skin. Precautions are urged to diminish exposure from both these absorption routes as the findings of the study support earlier reports regarding chronic vascular effects.

Adult↗

Localization and possible function of peptidergic neurons and their interactions with central catecholamine neurons, and the central actions of gut hormones.

The localization of various neuropeptides is described in the gut and in the hypothalamus in the rat. Evidence is given for the presence of material resembling corticotropin-like intermediate peptide in arcuate and periarcuate neurons, projecting to various hypothalamic nuclei, limbic areas and the thalamus. beta-Endorphin and glucagon decrease dopamine turnover in the median eminence, while secretin increases dopamine turnover and vasoactive intestinal polypeptide (VIP) has no effect. beta-Endorphin, VIP, secretin, and glucagon all produce discrete changes in norepinephrine turnover in various hypothalamic nuclei. Mainly increases of norepinephrine turnover were observed. These catecholamine turnover changes appear to cause changes in the secretion of prolactin and growth hormone. The results therefore indicate that gut hormones and opioid peptides may act directly on the hypothalamus on specific types of receptors to participate in the control of hypothalamic functions such as control of hormone secretion from the anterior pituitary and of food intake. It seems possible that gastrointestinal peptides released from the gastrointestinal tract into the circulation under certain circumstances could reach the hypothalamus and modulate its activity via the above-mentioned mechanisms. It may therefore be speculated that disturbances in gastrointestinal functions could lead to pathological changes in food intake via modulation of hypothalamic activity.

Adrenocorticotropic Hormone↗

Organic solvents and temperature effects on desorption from immunoadsorbents. DNP-BSA anti-DNP as a model.

Conditions for desorbing a DNP carrier from its immunoadsorbent were studied in various hydro-organic media at different pHs and temperatures, including the sub-zero range. It appeared that DNP--anti-DNP interaction is the result of a balance between various bonds and the best result (95% yield) was obtained in hydro-organic solvent at high pH and +30 degrees C.

Antigen-Antibody Complex↗

Effects of cigarette smoking on incidental memory.

The effects of cigarette-smoking in an immediate memory task were studied in two groups of 25 female students (habitual smokers) tested either under a control (no smoking) condition or after smoking one cigarette. The memory task, requiring immediate serial recall of eight words, showed no differences between the two groups. Subjects were, however, also tested on recall of the position of words on the screen (each word could appear in any of the four corners). On this measure of incidental recall, the non-smoking group was far superior to the smoking group. This finding is in agreement with results obtained with noise-induced arousal and with the view that attentional selectivity is greater during increased arousal.

Adult↗

Studies on humans exposed to airborne sewage sludge.

A clinical investigation was made among workers in a sewage treatment plant and age matched controls not exposed to sewage. Acute incidences of fever and eye symptoms were found in about 50% of the exposed population. Serum immunoglobulins, white blood cells and thrombocytes were elevated in the exposed group. A higher percentage of increased levels of C-reactive protein and fibrinogen degradation products was found in the exposed group. Although no definite cause-effect relationship can be established the responsible agent in the environment could well be endotoxins.

Air Pollution↗

Kinetics of the actions of tetracyclines on Escherichia coli as studied by microcalorimetry.

Microcalorimetry was used to study the kinetics of the actions of various tetracyclines on a strain of Escherichia coli. Differences in the capacity to suppress the metabolism of this bacterium were observed. When the antibiotic was present from the start of the experiment, a heat production of 2.0 muW/ml was registered after 12.5 h using minocycline; the corresponding figures for doxycycline, oxytetracycline, and tetracycline were 7.3, 6.6, and 4.5 h, respectively. In these experiments, equal concentrations, i.e., half the minimum inhibitory concentration (MIC), of each drug were used. The MIC for all the tetracyclines tested, determined by the broth dilution technique, was 0.8 mug/ml. In other experiments, the antibiotic (concentration, 1.6 mug/ml = 2x MIC) was introduced into the growth vessel during the logarithmic growth phase of the organism. The extent and duration of the inhibitory effect on the metabolism, as judged from the decrease in heat production, varied with the different tetracyclines. Immediately after introduction, minocycline, doxycycline, oxytetracycline, and tetracycline decreased the heat production in decreasing order of potency. With tetracycline, the heat production rose after about 1 h, and with minocycline it rose after about 9 h. The heat production remained at a low level for at least 19 h when using doxycycline and oxytetracycline. The results indicate that microcalorimetry offers a means for studies of the kinetics of the antibacterial actions of antibiotics and provides information that cannot be obtained by conventional bacteriological techniques. This information may be of use, in conjunction with pharmacokinetic data, in establishing optimum doses and dose intervals in antibiotic therapy.

Calorimetry↗