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Biomedical subjects

J Clausen

Publications and source records attributed to J Clausen.

At least 127 records · Page 7Linked to original sources
PubMed1982

Triethyl lead toxicity in relation to brain glutathione and glutathione S-transferase.

A dose-dependent decrease in the content of reduced glutathione (GSH) was found in the brain of rats following treatment with Pb(Et)3 for varying time intervals. Maximum inhibition of 19% was observed 3 h after the last dose of Pb(Et)3 (8 mg/kg) daily for 3 days. Glutathione S-transferase activity did not change significantly. In vitro, there was no conjugation of GSH with PbEt3 and the addition of brain cytosol did not catalyse the conjugation.

Animals↗
PubMed1982

Reaction time and psychophysiological activity.

Disjunctive reaction times (RT) involving two interstimulus intervals were obtained from 10 subjects during 4 sessions while recording heart period, skin conductance, and EEG. Multiple regression analysis indicated complex relationships between RT and skin conductance and heart period which varied with session level. The relationship of RT and skin conductance was predominantly linear but positive when level of skin conductance was low and negative when high. Heart period showed a predominantly curvilinear trend which also varied with level during the session. Fastest RTs tended to occur with long heart periods in short heart period sessions and vice versa. Fast RTs were also accompanied by relatively low EEG power before and after stimulation and by higher EEG frequency after the stimulus. The pattern of findings did not fully accord with the expectations of activation theory, and the proportion of RT variance accounted for was small. It is suggested that activation may vary to maintain a constant level of motor performance. Faster RT may occur under relaxed conditions and high arousal, and concentrated attentiveness may be an attempt to compensate for boredom or distraction.

Adult↗
PubMed1982

Lichen nitidus: electron microscopic and immunofluorescence studies.

Skin biopsies from a patient suffering from lichen nitidus were studied by electron microscopy and immunofluorescence studies. Complete disintegration of the stratum basale in the central area of the lesion and signs of acantholysis in the border area were found. In the central part of the lesion the dermo-epidermal junction was severely damaged in most places. In the dermal infiltrate, macrophages and lymphocytes were found with a considerable representation of Sézary cells, not previously reported in lichen nitidus. The ultrastructural changes are identical with those found in lichen planus. No in vivo bound immunoglobulins, fibrinogen, or complement C3 were found.

Adolescent↗
PubMed1982

Decreased lymphocyte aryl hydrocarbon hydroxylase and glutathione S-transferase activities in patients with hand dermatitis.

Aryl hydrocarbon hydroxylase (AHH) and glutathione S-transferase (GST) (EC 2.5.1.18) activity were measured in human lymphocytes of peripheral blood from 8 patients with irritant or allergic contact dermatitis of the hands, and compared with data from a control group. Both AHH and GST activity was found to be significantly depressed in the allergic and irritant contact dermatitis subjects, as compared with controls. It is suggested that AHH may be a quantitative marker of the inflammatory status.

Adult↗
PubMed1981

Electron microscopic study of the regeneration in vitro of rat peritoneal mast cells after histamine secretion.

Regeneration of rat mast cells was studied by TEM from 10 s to 48 h after secretion of histamine induced by compound 48/80. During the first 2 h, small intracellular cavities, formed during compound exocytosis and containing non-membrane-bound remnants of the granules, tended to coalesce, and after 2 h of incubation regeneration started. After 6 h, all the cavities had fused into one large central cavity which contained the remnants of the granules and remained open to the exterior during the entire period. The plasma membrane microfolds which disappeared just after secretion were reformed during regeneration. They were apparently involved in endocytotic-like activity and coated vesicles also appeared beneath the plasmalemma (membrane recycling?). The fate of the granule remnants in the cavity is unknown, as regeneration was not completed after 48 h which is the longest survival time obtained so far in ultrastructural studies of mast cell regeneration in vitro.

Animals↗
PubMed1981

Surface morphology of rat peritoneal mast cells during in vitro regeneration after histamine secretion.

Cell-surface morphology of regenerating mast cells was followed over a period of 48 h after histamine release. Control cells (not stimulated to secrete) were characterized by anastomosing folds of membrane of equal depth and width. During exocytosis these folds disappeared and were replaced by deep cup-shaped flaps of membrane evident in cells incubated for 10 min. During the first hours of regeneration these flaps fused mutually or with the plasma membrane. This activity suggests membrane retrieval, maybe specifically recycling the granule-type patches of membrane. Membrane-fusion activity was observed to some degree also after extended incubation. After 48 h of incubation the regeneration process was still not completed, as indicated by the fact that holes leading to intracellular cavities could still be found.

Animals↗
PubMed1981

Triethyllead treatment of cultured brain cells. Effect on accumulation of radioactive precursors in galactolipids.

Cultured cells from chick embryo brains were studied for their sensitivity to triethyllead. Triethyllead chloride (3.16 microM) was added to the nutrient medium and incubated for 48 hr with the cells. Morphological changes in light microscope and radioactive labeling of galactolipids were assayed. Triethyllead treatment reduced the number of neuronal cells with processes. Morphological changes were not observed in glial cells. The [35S]sulfate labeling of sulfatides was reduced to 50%. The [3H]serine labeling of cerebrosides with alpha-hydroxy fatty acids was not influenced, while the [3H]serine labeling of cerebrosides with nonhydroxy fatty acids was inhibited 40% in one- and two- but not in three-week-old cultures. The results indicate that the nerve cell response to triethyllead in cultures is selective, since the neurons are more sensitive than the glia cells and the labeling of sulfatides is more sensitive than that of cerebrosides.

Animals↗
PubMed1981

Subcellular distribution of the cytochrome P-450 complex and glutathione peroxidase activity in vitamin E and essential fatty acid deficiency.

Glutathione peroxidase (EC 1.11.1.9.) (GSHPx) and P-450 activity were measured in hepatic mitochondrial and microsomal fractions from rats deficient in vitamin E and/or essential fatty acids (EFA). The data were compared to corresponding normal values. GSHPx was significantly decreased in the mitochondrial matrix from animals in all 3 deficiency states. In vitamin E deficiency, a non-significant decreased GSHPx activity was found in mitochondrial membranes. Opposite to these findings, GSHPx was significantly increased in mitochondrial membranes of EFA-deficient animals. In combined EFA and vitamin E deficiency, the mitochondrial membrane GSHPx activity was only insignificantly increased. The P-450 complex activity was not detectable in the mitochondrial matrix. In mitochondrial membranes and microsomes, the P-450 complex activity changed parallel to the GSHPx activity.

Animals↗
PubMed1981

Degradation of basic protein and Wolfgram protein in central nervous system by soluble enzymes of human peripheral polymorphonuclear leucocytes.

The present communication describes the ability of soluble enzymes (SE) of peripheral polymorphonuclear leucocytes of control and multiple sclerosis (MS) patients to degrade major myelin proteins of MS and control myelin. MS and control SE degraded in situ both Wolfgram protein (WP) and basic protein (BP) of isolated myelin. No differences were found between the action of control and MS patients SE on myelin. However, significantly less degradation of BP and WP in control myelin compared to that in MS myelin was found. Only 30% of SE samples (both control and MS) degraded significant amounts of proteolipid protein in myelin. It is postulated that SE associated demyelination in MS may be a factor contributing to the demyelinating process.

Adult↗
PubMed1981

Mixed function oxidase and glutathione S-transferase activities in normal human peripheral blood lymphocytes.

The carcinogenic activity of some chemicals may be related to uncoupling of metabolism mediated by the mixed function oxygenase system. The intermediate formation of reactive epoxides or hydroxylamines may be eliminated by glutathione S-transferase. The ratio between these 2 enzymic activities may indicate if individuals are prone to cancerous development. If adequate cellular samples are available, assay of these enzymes may be used to trace individuals at risk. Therefore the present paper estimates these 2 enzymic activities (i.e., aryl hydrocarbon hydroxylase (AHH) and N-demethylation, the metabolite forming enzyme activities and glutathione S-transferase, the metabolite detoxifying enzymes), in the peripheral blood lymphocytes of 35 subjects. Their median age was 34 years. AHH activity was increased by 52% in the lymphocyte homogenate and by 45% in the microsomal fraction of smokers when compared with non-smokers. The enzyme activity also increased by 73% in the homogenate and by 93% in the microsomes of those taking drugs. The activity of N-demethylase increased by 212% in microsomes of smokers. However, the glutathione S-transferase activity decreased by about 2% in the lymphocyte homogenate and cytosol of smokers. The subjects taking drugs showed a decrease in this enzyme activity by 8% in the homogenate and by 37% in the cytosol.

Aryl Hydrocarbon Hydroxylases↗
PubMed1981

Abnormal serum alpha 2-macroglobulin in multiple sclerosis.

Crossed immunoelectrophoresis (CI) of serum alpha 2-macroglobulin (alpha 2-M) of neurological patients revealed that alpha 2-M in serum of multiple sclerosis (MS) patients was abnormal. Thus the immunoprecipitate of alpha 2-M appeared asymmetric arguing for the presence in MS serum of two alpha 2-M of different electrophoretic mobilities but with (partially) identical immunological properties. In order to study if this abnormality could be used as a diagnostic tool, 50 coded serum samples were studied by CI. After the evaluation by CI, the decoding revealed that 85% of the MS patients possessed abnormal alpha 2-M as described. By employing the present method only 16% of the non-MS patients were mixed with the MS group. The pathogenic role of the present findings is discussed.

Adult↗
PubMed1981

Glutathione peroxidase activity in vitamin e and essential fatty acid-deficient rats.

Gluthathione peroxidase (EC 1.11.1.9, GSHPx) activity was measured in whole liver, in hepatic cytosol and in whole mitochondria from normal rats and from rats subjected to experimentally induced vitamin e and/or essential fatty acid (EFA) deficiency. The animals were fed and raised on the specific diets for 6 months. The GSHPx activity was significantly decreased in all samples of EFA-deficient rats. This group exhibited a significant increased 29:3omega9 content and to low 20:4omega6 content. In rats fed a vitamin E-deficient diet, the GSHP x activity was significantly decreased in hepatic cytosol. When the data of all experimental groups were pooled the specific GSHP x activities of the hepatic cytosol correlated significantly to that of whole mitochondria. The specific GSHP x activity of the whole liver, the mitochondrial and the cytosol fractions were found higher in female than in male rats in controls as well as in deficient animals. This difference was affected by the EFA deficiency. In EFA-deficient mitochondria the sex difference in enzymic activity was decreased (half of normal difference). In EFA-deficient cytosol the difference was increased (double of normal difference). However, the total hepatic GSHPx activities were not significantly higher in female than in male rats in any of the groups studied. Thus, EFA deficiency is added to the list of factors influencing the GSHPx activity. It is concluded that it is not possible to use GSHPx activity as a marker for the selenium status in domestic animals such as suggested previously. Thus, selenium is only one of the factors governing the GSHPx level.

Animals↗
PubMed1981

The ultrastructure of the dermo-epidermal junction in lichen planus.

The ultrastructure of the dermo-epidermal junctional area in biopsy material from 5 patients suffering from lichen planus has been studied during treatment with steroids. Tannic acid was used on the tissue blocks in order to provide high and diversified contrast for electron microscopy. The changes observed in the basal cells consisted mainly of degeneration of the mitochondria and disorganization of the tonofilaments. No ultrastructural changes were seen in the basal lamina, apart from occasional gaps, whose significance for pigment incontinence in old lichen planus lesions is discussed. Cellular infiltration was seen in the dermis, while the ultrastructure of the collagen fibrils of the papillary layer was normal. It is suggested that degeneration of mitochondria with subsequent disturbance of the organization and fixation of tonofilaments are events in the pathogenesis of the condition.

Adolescent↗
PubMed1980

A simple method for the isolation of multiple sclerosis specific brain antigens.

A method for isolation of two multiple sclerosis(MS)-specific brain antigens [3] is described. The brain cytosol was passed through a Con A-Sepharose column and the glycoproteins containing MS-specific antigens (MSG) were eluted with 50 mmol/l methyl-alpha-D-glucopyranoside, pH 6. By fractionation of MSG on DEAE-cellulose, a fraction containing MS-specific antigens (MSG2) was eluted in 0.25 mol/l NaCl, after prior elution of other proteins with distilled water. The MS specific antigens in the MSG2 fraction were traced and characterized by crossed immunoelectrophoresis and isoelectric focusing. A quantitative determination of proteins eluted in MSG2 revealed that the 2 MS-specific antigens had been purified 10 000 times. Using this method to isolate the two MS-specific antigens of autopsy brains, they were found to be present in 7/7 MS brains and absent in 9/9 non-MS brains studied. The method described in the present communication may be used both for the partial purification of the MS-specific antigens as well as for the tracing of the specific antigens in different topographical areas of the MS brains.

Adult↗