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Biomedical subjects

A Schweitzer

Publications and source records attributed to A Schweitzer.

At least 55 records · Page 3Linked to original sources
PubMed1981

Autoradiographic and biochemical observations on the distribution of non-steroid anti-inflammatory drugs.

A comparison has been made of the distribution of some new radioactively-labelled non-steroid anti-inflammatory (NSAI) drugs or pro-drugs with their respective progenitors and/or standard acidic NSAI drugs (i.e. aspirin, indomethacin and phenylbutazone), using whole body autoradiography and scintillation counting. The object of this study was to establish if the distribution of these new NSAI drugs may contribute to changes in their side-, or therapeutic effects compared with the older drugs. All the NSAI drugs accumulated in those tissues wherein the principle therapeutic and side-effects are manifest. The accumulation in inflamed tissues occurs regardless of the structural type of NSAI drugs, i.e. with specific accumulation occurring in this tissue of the acidic drugs or their acidic metabolites. New aspects of the distribution of the acetyl moiety of aspirin are reported which may be significant in relation to the side-effects induced by this drug.

Animals↗
PubMed1980

Bio-distribution in rats of some salicylates with low gastric ulcerogenicity.

The distribution of three radioactively labelled salicylate derivatives with low ulcerogenic activity was compared with that of acetylsalicylic acid (ASA) and salicylic acid using whole body autoradiography and liquid scintillation counting techniques in rats. The methyl ester of ASA (AME) was distributed in vivo very similarly to that observed with ASA and salicylic acid. AME is rapidly demethylated following absorption from the stomach and is subsequently converted to ASA and salicylate. Salicylate is the main metabolite produced from both AME and ASA, which specifically accumulates in inflamed tissues. The 3-methyl- and 6-methyl-substituted salicylic acids are not as rapidly absorbed as either ASA or salicylic acid and do not pass readily into the brain or bone marrow. These results show that the methyl (ester) group of AME (which adequately protects the gastric mucosa from damage caused by ASA itself) does not impair the quantity of pharmacologically active form of drug (salicylate and ASA) generated in vivo. However, insertion of the methyl group at the 3- and 6-position of salicylic acid markedly affects both absorption, distribution and pharmaco-activity of these acids.

Animals↗
PubMed1980

Biodistribution of mild analgesics.

1 Macro-autoradiographic methods were used to assess the biodistribution of [3H]-, or [14C]-acidic (aspirin, indomethacin, phenylbutazone) and non-acidic (antipyrine, aminopyrine, paracetamol) mild analgesics in rats with carrageenan-induced inflammation. 2 At anti-inflammatory doses all the acidic drugs (and/or their metabolites) were found to reach high concentrations in the stomach wall, liver, blood and bone marrow, kidney cortex and the inflamed tissue, that is, the tissues in which these drugs exert their therapeutic or side-effects. 3 In contrast, at analgesic doses, the non-acidic mild analgesics (and/or their metabolites) are equally distributed throughout the body with the exception of the gastro-intestinal lumen and the liver. This distribution pattern correlates well with the lack of acute side-effects and anti-inflammatory action of these drugs at therapeutic doses.

Analgesics↗
PubMed1980

Propranolol and hydrallazine in the management of essential hypertension in pregnancy.

A combination of propranolol and hydrallazine was administered to 13 patients with longstanding hypertension during 15 pregnancies. Hydrallazine was continued through labour and delivery in all patients, while in eight patients propranolol was discontinued 2 to 15 days before delivery. Blood pressure control was uniformly good and superimposed pre-eclampsia did not occur during combined therapy. There were 14 livebirths and one unexplained stillbirth. Except for two cases of milk hypoglycemia, there were no neonatal complications.

Adult↗
PubMed1979

In vitro granulopoiesis in oligoblastic leukaemia: prognostic value, characterization and serial cloning of bone marrow colony and cluster forming cells in agar culture.

The colony and cluster forming capacity of bone marrow cells (BM CFC and CluFC) in agar culture, was studied from 20 oligoblastic patients. 13 patients had a leukemic growth pattern and 12 of these died within one year after diagnosis. 7 patients had no leukemic growth and 4 are alive 16 to 90 months after diagnosis. Both the determination of the proportion of abnormally light buoyant density of CFC and CluFC and the study of their suiciding index were used to characterize more precisely the leukemic or nonleukemic status of patients. Because of the small number of patients involved in the later preliminary study, the prognostic significance cannot be valuated. Serial studies of individual patients showed different types of evolution in the growth pattern of BM CFC and CluFC. Either the increase of BM CFC and CluFC paralleled that of the myeloblasts, or there was a change in the growth pattern before AML transformation suggesting clonal evolution.

Aged↗
PubMed1978

[Pathophysiology of burns].

Ultrastructural and metabolic alterations of the liver were studied in mice and rats after standardized "in vivo" burn injuries or i.p. injections of a specific cutaneous burn toxin. The main findings of the ultrastructural investigations were delayed and specific intramitochondrial vacuolizations appearing not before the 5th-7th day after burning or toxin-injections. -By applying the Schimassek model of the isolated and perfused liver for investigating liver metabolism we found a drastically reduced ATP/ADP-quotient on the 5th day after burns or toxin-injection as compared to the normal controls. The total content of adenonucleotides, however, remained unchanged. The urea and glucose release into the perfusate was also significantly decreased in both groups of animals and the glucose synthesis was not adequately stimulated by an additional lactate load. The results show a direct effect on the burn toxin on the hepatic metabolism as well as the hepatic cell structure suggesting a marked alteration of the oxydative phosphorylation.

Adenosine Diphosphate↗
PubMed1978

Treatment with propranolol and hydralazine throughout pregnancy in a hypertensive patient. A case report.

A chronic hypertensive patient was treated with alpha-methyldopa and diuretics throughout the 30 weeks of her second unsuccessful pregnancy. Treatment with propranolol and hydralazine was effective in controlling her blood pressure and was continued throughout her next two pregnancies, both of which were successful. No adverse reactions were observed in either the mother or the infants. The possibility that this combined treatment is beneficial to both mother and child in such cases should be further explored.

Adult↗
PubMed1977

[Comparative transmission and scanning electron microscopy studies of liver changes in mice followed sublethal skin burns and intraperitoneal injection of a specific skin burn toxin].

Ultrastructural alterations of the liver were examined on the 1st, 2nd, 3rd, 5th, 7th and 14th day after a standard burn in mice. Our results can be divided pathogenetically into two groups: 1. Alterations explained by the primary thermal injury including electron-optically empty vacuoles and sinusendothelium destruction. 2. Alteration due to the influence of a specific burn toxin including mitochondrial changes and the formation of autophagic vacuoles. Evidence of this distinction was produced by a second investigation. Burn toxin isolated from the serum of severely burned patients was injected intraperitoneally (15 mg) into 4 mice. The livers were examined by electron microscopy on the 2nd, 4th, 7th and 14th day. Alterations described in 2 above were not observed in any case of this investigation series. The nature and timing of liver alterations were similar to those described in 2 above. In none of the cases were changes similar to those in 1 above observed.

Animals↗
PubMed1977

Tension generation by isolated myofibrils.

The technique for mechanical dissection of microscopic myofibrilar bundles containing few myofibrils is described. A sensitive electrooptical tension transducer capable of resolving the tension generated by such myofibrilar bundles to within a fraction of a percent is used to study the response of the preparations to low ATP concentrations. The rate of tension development decreased with a decrease in ATP concentration. Below 10(-6) M ATP the myofibrils did not demonstrate any mechanical activity at all. These findings are discussed in terms of the kinetics of the cross-bridge cycle.

Adenosine Triphosphate↗