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Biomedical subjects

B Pettersson

Publications and source records attributed to B Pettersson.

At least 127 records · Page 7Linked to original sources
PubMed1983

The toxicity of menthol in short-term bioassays.

The toxicity of menthol was studied on 4 different in vitro systems covering organ, cellular and subcellular levels. The 50% inhibitory concentration (IC50) for the cellular and subcellular systems ranged from 0.32 mM to 0.76 mM. At a concentration of 0.5 mM menthol the receptor mediated respiratory stimulation of isolated brown adipocytes was markedly inhibited while the intracellular mitochondrial functions were still unaffected. However, using isolated rat liver mitochondria 0.5 mM menthol was found to cause increase in the 'state 4' respiratory rate and osmotic swelling, indicating a leakage of the mitochondrial membrane. We therefore suggest that one effect of menthol is a deterioration of biological membranes. For the determination of the cellular toxicity of foreign compounds isolated brown adipocytes represents a convenient and sensitive model, providing the possibility to localize the primary site of action in terms of mitochondrial or extramitochondrial level.

Adipose Tissue, Brown↗
PubMed1983

The effect of different levels of polishing of amalgam restorations on the plaque retention and gingival inflammation.

This study was performed to elucidate the effect of different levels of polishing of amalgam restorations as part of the treatment of patients with gingivitis and/or incipient periodontitis on plaque retention and gingival inflammation. The results indicate that contouring of restorations and removal of marginal overhangs using diamond tips and conventional finishing burrs is sufficient to permit adequate tooth cleaning and that further polishing using rubber discs, rubber tips and polishing pastes does not result in further improvement of gingival health.

Adult↗
PubMed1982

Determination of bacmecillinam, an amdinocillin prodrug, in human and canine whole blood by reversed-phase liquid chromatography.

Bacmecillinam is an amdinocillin prodrug designed to be easily hydrolyzed in biological materials, so special procedures were developed for the collection of blood specimens. Whole blood was collected in tubes containing bacampicillin as an adsorption inhibitor and kept at -70 degrees; the extracting solvent, hexane-methylene chloride (9:1, v/v), was added to the cold tubes, and the extraction was performed during the thawing of the samples. The organic phase was partially evaporated before a reextraction to a small volume of acidic aqueous phase was made. The separation was performed on a microparticulate. C18-alkyl bonded silica packed in glass-lined stainless steel columns. Mobile phase was a buffer (pH 6)-acetonitrile mixture containing N-hexyl-N-methylamine as an adsorption inhibitor. The detection limit was 600 pg/ml of whole blood, and the within-run precision (srel%) was approximately 8% at the 5-ng/ml level.

Amdinocillin↗
PubMed1982

Effects of tobacco smoke compounds on the ciliary activity of the embryo chicken trachea in vitro.

The ciliotoxicity of 316 individual compounds representative of the gaseous and semivolatile phases of tobacco smoke has been investigated using chicken tracheal organ cultures. When examined at 5 mM concentration and measuring the time to complete ciliostasis, 36% of the compounds were found to cause ciliostasis within 15 min, while about 50% had no visible effect on the ciliary activity during a 60-min exposure. The majority of the ciliotoxic compounds were either alkylated phenylethers, benzonitriles, benzaldehydes, phenols, benzenes, naphthalenes and indoles, or alpha, beta-unsaturated ketones and aldehydes or C6-C10 aliphatic alcohols, aldehydes, acids and nitriles. Most of the compounds classified as benzoic acids, esters, polyaromatic hydrocarbons, amines and N-heterocycles, except indoles, were found to be inactive.

Animals↗
PubMed1982

Purification and partial characterization of two acidic proteases from the white-rot fungus Sporotrichum pulverulentum.

Two acidic proteases from the white-rot fungus Sporotrichum pulverulentum have been purified and partially characterized. The enzymes were purified in four steps, protease I 152-fold and protease II 127-fold. The purity of the enzymes was investigated by analytical isoelectric focusing and by dodecylsulfate/polyacrylamide gel electrophoresis. The isoelectric points of protease I and protease II were at pH 4.7 and 4.2 respectively. The molecular weights were 28,000 and 26,000 and the pH optima 5.0 and 5.2. Both enzymes were inhibited by heavy metal ions such as Ag+, Hg2+ and to some extent also by Cu2+. Partial inhibition was also observed with EDTA and alpha, alpha'-dipyridyl. The specificities of protease I and II were investigated using human fibrinopeptide A as substrate. Protease I splits off the arginine in the C-terminal position, while protease II splits at the carboxyl side of both Phe-8 and Leu-9 in fibrinopeptide A. A physiological effect of the two proteases has also been demonstrated. Thus, if a culture solution from S. pulverulentum grown on cellulose was treated with the individual proteases or a mixture of the enzymes a considerable increase in endo-1,4-beta-glucanase activity was obtained. It may be that the endo-glucanases are produced in a zymogenic form and activated by the proteases. However, other explanations for the phenomenon are also possible.

Cellulase↗
PubMed1980

Isolated hamster brown fat cells: a bioassay for toxicity tests at the cellular level. Effect of cigarette smoke condensates from high and low tar yield cigarettes.

A test system for the detection of substances with cell-irritating or cell-damaging effects using isolated brown fat cells is presented and the effects of cigarette smoke condensates (CSC) from high and low tar yield cigarettes on this system examined. The condensates inhibited noradrenaline stimulated respiration in a dose-dependent manner. Ethanol solutions of the condensates had a stronger inhibitory effect than DMSO solutions. The CSC strongly inhibited the mitochondrial function but other cellular functions were also impaired.

Adipose Tissue, Brown↗
PubMed1980

Effects of tobacco smoke compounds on the noradrenaline induced oxidative metabolism in isolated brown fat cells.

The effect on cell metabolism of 320 individual smoke components have been investigated by measuring their inhibition of noradrenaline induced respiration in isolated hamster brown fat cells. The compounds are representative of the gaseous and semivolatile phases of tobacco smoke. The strongest inhibitors were found within the groups of aliphatic alcohols, aldehydes and acids, of alkylated phenols and indoles and of alpha,beta-unsaturated aliphatic aldehydes and ketones. Some of the aliphatic aldehydes and acids significantly increased the basal respiration of the cells, probably by acting as substrates and/or uncoupling of mitochondrial respiratory control.

Adipose Tissue, Brown↗
PubMed1979

Flavoprotein-linked substrate oxidation in preparations of hamster brown adipocytes. A discrimination between internally and externally oxidized substrates.

Noradrenaline-stimulated oxidative metabolism in isolated hamster brown fat cells is very reproducible between different cell preparations, 565 +/- 81 (S.D.) nmol O/min per 10(6) cells (n = 25). In contrast, the oxygen consumption rate induced by the addition of succinate or sn-glycerol 3-phosphate strongly varies between different cell preparation, although these substances have been reported to be potent substrates for isolated hamster brown fat cells. By filtration and by successive washings we demonstrate that the flavoprotein-linked substrate oxidation is mainly dependent on extracellular succinate and sn-glycerol 3-phosphate-oxidizing enzymes. These enzymes originate from damaged and broken cells and are present in different amounts in different cell preparations. In discriminating between intra- and extracellular succinate oxidation 5,5'- dithiobis(2-nitrobenzoate) is used as an inhibitor of the extracellular portion. This application of 5,5'-dithiobis(2-nitrobenzoate) ought to be useful also in other cell or tissue preparations. Added succinate can, however, be oxidized by the intact brown adipocyte but at very low rate, probably as a result of a limited transport rate over the membrane(s). In the presence of noradrenaline, added succinate can potentiate the noradrenaline-inducible oxygen consumption by catalytically increasing the oxidative capacity of the citric acid cycle. Our conclusions is that the only effectors which significantly increase oxidative metabolism in intact isolated hamster brown fat cells are catecholamines and free fatty acids. Provided the cells are uncoupled, also pyruvate can function as substrate for these cells.

Adipose Tissue, Brown↗
PubMed1977

Prediction of cardiovascular deaths and non-fatal reinfarctions after myocardial infarction.

The present study concerns the development and validation of a logistic multivariate prognostic function in patients followed for two years after myocardial infarction. The patients studied constituted at least 90% of all cases in a total community--the City of Göteborg, Sweden. Using a multivariate logistic function with 7 variables, based on 30 cardiovascular deaths during two years after discharge from hospital among 292 men with first infarction, breathlessness at onset of symptoms of infarction, SGOT quartile, left heart failure, relative heart size, atrial fibrillation, a history of hypertension, and AV block recorded during the hospital phase were the most important variables. The first five of these variables made significant contributions (p less than 0.01) to the predictive power. The predictive capacity was confirmed in an independent series of 195 men with first infarction, among whom 17 cardiovascular deaths occurred. Around 60% of the total cardiovascular mortality was concentrated in the highest risk quintile. Deaths from non-cardiovascular causes were predicted less efficiently. Non-fatal recurrences could not be predicted by the present model. Thus, the function can predict the excess risk of mortality but not the excess risk of reinfarction during two years among men after an initial myocardial infarction.

Aspartate Aminotransferases↗
PubMed1977

CO2-mediated control of fatty acid metabolism in isolated hamster brown-fat cells during norepinephrine stimulation.

1. Addition of norepinephrine to isolated hamster brown-fat cells suspended in Krebs-Ringer phosphate buffer induces a pronounced, but temporary increase in respiratory rate. 2. If Krebs-Ringer phosphate buffer is bubbled with CO2 prior to the addition of cells and norepinephrine, the respiratory capacity of the cells is further potentiated and most important, the respiration is maintained at a high rate until the medium becomes depleted of oxygen. 3. This respiratory pattern cannot be obtained in CO2-bubbled Krebs-Ringer bicarbonate buffer. 4. The results indicate that CO2 has a regulatory effect on fatty acid metabolism in isolated hamster brown-fat cells.

Adenosine Diphosphate↗
PubMed1976

Norepinephrine-induced shift in levels of adenosine 3':5'-monophosphate and ATP parallel to increased respiratory rate and lipolysis in isolated hamster brown-fat cells.

1. Isolated brown fat cells from hamster respond to added catecholamines with a temporary increase in respiratory rate and an extended lipolysis. 2. From experiments with catecholamines and alpha and beta-blockers, the receptors of these cells are classified as beta according to classical definition. 3. Norepinephrine induces a rapid increase in adenosine 3':5'-monophosphate levels which parallels in time the stimulated respiration. Maximal adenosine 3':5'-monophosphate levels are reached within 1-3 min and are followed by a continuous decline. 4. Parallel to the catecholamine-induced respiration and lipolysis there is a pronounced drop in ATP levels. This energy depletion could be reversed by addition within 5 min after norepinephrine of the beta-blocker propranolol. 5. The nucleotide pattern in isolated hamster brown fat cells after norepinephrine addition was mimicked in experiments with isolated hamster brown fat mitochondria. From these experiments it is concluded that a high ratio of AMP and ADP over ATP decreases the respiratory rate when endogenous free fatty acids are oxidized.

Adenosine Diphosphate↗
PubMed1976

A comparison between agar gel electrophoresis and CSF serum quotients of IgG and albumin in neurological disease.

CSF and serum was obtained from 216 patients with neurological or psychoneurotic symptoms and the concentrations of albumin and IgG were immunologically determined. The IgG/albumin index, calculated as the quotient of the CSF/serum ratios of IgG and albumin was compared with electrophoresis on agar gel. In "normal" cases, the IgG/albumin index was between 0.26-0.66. Pathological electrophoresis, i.e. with two or more IgG bands in the gamma globulin region was found in 85 per cent of the MS patients; in 29 per cent of the patients with a possible demyelinating disease; in 41 per cent of patients with CNS infection; and in 4 per cent of patients with other neurological disorders; whereas an increased IgG/albumin index ( greater than 0.66) was found in 88 per cent of the MS patients; in 43 per cent of the patients with a possible demyelinating disease; in 50 per cent of the patients with CNS infection; in 11 per cent of patients with immunological disorders; and in 18 per cent of patients with other neurological diseases. The increase of the IgG/albumin index was sometimes moderate (0.67-0.90), except in patients with MS, syphilis and other CNS infections, where a pathological electrophoresis combined with an IgG/albumin index above 1.0 was found to be a valuable support for the clinical diagnosis.

Adolescent↗