PubMed Health⌕ Search

Biomedical subjects

G Müller

Publications and source records attributed to G Müller.

At least 469 records · Page 26Linked to original sources
PubMed1987

Reduced behavioural inhibition after lesions in the dorsomedial pontine reticular formation of rats.

Male hooded rats of the Long-Evans strain were investigated in an open field (OF), in an Y-maze and in a pole-climbing (jump) test before and after small bilateral symmetric lesions of the dorsomedial pontine reticular formation, medial from the locus coeruleus including lateral parts of the central gray. Postoperative values of ambulatory activity were increased above 300%. This hyperactivity in the OF was characterized by weakened habituation in the OF, increased locomotor speed, increased climbing rate, whereas horizontal exploratory activity was significantly decreased. The preoperatively learnt Y-maze avoidance tasks were correctly performed after lesions without any retention deficit and without errors in brightness-discrimination. The postoperative acquisition of a jump test avoidance task was impossible because the lesioned rats did not find the escape possibility in spite of a great number of variant jumps. They never showed tendencies of arrest behaviour ("learned helplessness"). The syndrome is characterized by weakened behavioural inhibition of incorrect or redundant responses.

Animals↗
PubMed1987

[Comparative local and systemic immunization against experimentally-induced Bordetella bronchiseptica pneumonia in ICR mice].

It is described the experimental Bordetella bronchiseptica infection via aerosol in ICR mice. 10(6) living bacteria were found in the lung after aerosol challenge with a total of 10(12) CFU. The pneumonias produced in this infection model within 10 days are focal, interstitial and proliferative to a low and medium degree, respectively. They are significantly reduced already by a single i.p. or s.c. immunization. Two vaccinations with inactivated Bordetellae or a temperature sensitive mutant reduce the frequency and severity of the pneumonias, dependent on the administered immunizing dose. The efficacy of two consecutive immunizations via aerosol is comparable to that of two i.p. vaccinations.

Administration, Inhalation↗
PubMed1986

[Thiobarbituric acid positive substances as indicators of lipid peroxidation].

Polyenic acids of particularly membrane-bound lipids can be disintegrated non-enzymatically by oxygen radicals or enzymatically by peroxidation. Final products of the lipid peroxidation are malon dialdehyde, n-alcanes, n-alcanales, hydroxyalcanales, 2-alcenales. Alca-2,4-dienales. Hydroxyalcenales and ketones. Products of lipid peroxidation can react with proteins and glycosaminoglycans. Thus receptor binding of the LDL, enzyme activities, DNA- and protein synthesis can be inhibited. Of the peroxidation products malon dialdehyde is relatively specifically recognizable by the reaction of the thiobarbituric acid. Size and clinical significance of processes of lipid peroxidation are up to now only little known in several diseases, but they might be of great importance for numerous pathological processes.

Chemical Phenomena↗
PubMed1986

Reversion of the transformed phenotype of B16 mouse melanoma: involvement of an 83 kd cell surface glycoprotein in specific growth inhibition.

Treating B16 mouse melanoma cells with monoclonal antibody NORM-2 reduces cell growth in tissue culture, agar, and syngeneic mice. We show that the NORM-2 antibody recognizes an integral 83 kd glycoprotein that is mobile in the plane of the plasma membrane of B16 melanoma cells. Expression of the glycoprotein is reduced under conditions that inhibit B16 growth, such as low serum, high cell density, and addition of transforming growth factor-beta. The glycoprotein reappears during S phase, when growth-arrested cells are restimulated. The NORM-2 antigen appears to be involved in growth regulation of B16 melanoma cells both in vitro and in vivo.

Animals↗
PubMed1986

Influence of a cod liver oil diet in healthy and insulin-dependent diabetic volunteers on fatty acid pattern, inhibition of prostacyclin formation by low density lipoprotein (LDL) and platelet thromboxane.

Ten healthy and twenty diabetic volunteers (type 1) received 15 capsules (à 450 mg) cod liver oil for 2 weeks daily in addition to a "normal" diet. The levels of eicosapentaenoic acid in the plasma phospholipids of both groups were increased after the treatment. The inhibition of the prostacyclin formation by LDL was diminished when the LDL was isolated after the treatment in comparison to LDL taken in the same concentration and from the same donors before it. The thromboxane B2 (TXB2) synthesis capacity of clotting whole blood, thrombin-induced TXB2 formation by platelets as well as the 15(S)-hydroxy-11 alpha,9 alpha-epoxymethano-5Z, 13E-prostadienoic acid-induced platelet aggregation were not altered by the treatment in healthy volunteers, whereas in diabetics the TXB2 formation capacity of clotting whole blood was decreased after the treatment in comparison with before it.

Adult↗
PubMed1986

[Transforming growth factor beta and fibroblast growth factor have opposite effects on the proliferation of endothelial cells].

Recent data indicate that beta type transforming growth factor (TGF-beta) may be a bifunctional regulator of cellular growth: it induces anchorage-independent growth of certain cells but is also capable of inhibiting anchorage-dependent or -independent proliferation of a variety of normal epithelial and transformed cells. We show that TGF-beta is also a reversible inhibitor of proliferation of bovine aortic endothelial cells in culture. TGF-beta inhibits the proliferation of endothelial cells grown in the presence of basic fibroblast growth factor (bFGF). Dose-dependent inhibition occurs at 0.2-2.0 ng/ml TGF-beta. Inhibition of cell proliferation in the presence of a maximally stimulating dose of bFGF is not overcome by a tenfold excess of bFGF, suggesting that antagonism of bFGF-induced cell proliferation by TGF-beta is of a non-competitive nature. TGF-beta affects the morphology of confluent cells in a reversible manner.

Animals↗
PubMed1986

Transforming growth factor-beta inhibits endothelial cell proliferation.

Transforming growth factor-beta (TGF-beta) is an inhibitor of the proliferation of bovine aortic endothelial cells in culture. Basal cell growth in serum-containing medium and cell proliferation stimulated by fibroblast growth factor (FGF) are inhibited by TGF-beta in a dose-dependent manner. Half-maximal inhibition occurs at an inhibitor concentration of 0.5-1.0 ng/ml. TGF-beta does not appear to be cytotoxic and cells treated with the inhibitor grow normally after removal of TGF-beta. High concentrations of FGF are ineffective in overcoming TGF-beta-induced inhibition of cell proliferation, suggesting that antagonism of growth factor-induced cell proliferation by TGF-beta is of a noncompetitive nature.

Animals↗
PubMed1986

[Relations between lipid metabolism and changes in the vessel wall].

Hyperlipoproteinaemias and dyslipoproteinaemias, respectively, lead to an increased lipid infiltration of the vascular wall. Increased lipid transport takes place vesicularly, by adsorptive endocytosis, contraction of the endothelium and dilation of interendothelial grooves. The increasedly taken lipids are bound to glycosaminoglycanes or elastin. The decomposition of the lipoproteins taken in the vascular wall is decreased. The lipid accumulation stimulates the glycosaminoglycane, elastin and collagen synthesis of the vascular wall.

Arteriosclerosis↗
PubMed1986

Characterization of solubilized insulin receptors from rat liver microsomes. Existence of two receptor species with different binding properties.

Insulin receptors were solubilized from rat liver microsomes by the nonionic detergent Triton X-100. After gel filtration of the extract on Sepharose CL-6B, two insulin-binding species (peak I and peak II) were obtained. The structure and binding properties of both peaks were characterized. Gel filtration yielded Stokes radii of 9.2 nm (peak I) and 8.0 nm (peak II). Both peaks were glycoproteins. At 4 degrees C peak I showed optimal insulin binding at pH 8.0 and high ionic strength. In contrast, peak II had its binding optimum at pH 7.0 and low ionic strength, where peak I binding was minimal. For peak I the change in insulin binding under different conditions of pH and ionic strength was due to a change in receptor affinity only. For peak II an additional change in receptor number was found. Both peaks yielded non-linear Scatchard plots under most of the buffer conditions examined. At their binding optima at 4 degrees C the high affinity dissociation constants were 0.50 nM (peak I) and 0.55 nM (peak II). Sodium dodecyl sulfate/polyacrylamide gel electrophoresis of peak I revealed five receptor bands with Mr 400 000, 365 000, 320 000, 290 000, and 245 000 under non-reducing conditions. For peak II two major receptor bands with Mr 210 000 and 115 000 were found. The peak II receptor bands were also obtained after mild reduction of peak I. After complete reduction both peaks showed one major receptor band with Mr 130 000. The reductive generation of the peak II receptor together with molecular mass estimations suggest that the peak I receptor is the disulfide-linked dimer of the peak II receptor. Thus, Triton extracts from rat liver microsomes contain two receptor species, which are related, but differ considerably in their size and insulin-binding properties.

Affinity Labels↗
PubMed1986

Investigations on metabolism, genotoxic effects and carcinogenicity of 2,2'-dichlorodiethylether.

Either 40 mumole or 160 mumole 2,2'-DDE was injected into male Wistar rats and the metabolites, TdGA and HEMA, were determined in the 24-h urine specimens. Comparative investigations were carried out giving equimolar amounts of chloroethanol and 2-chloroacetaldehyde diethyl acetal. In a further step, inhalation experiments were performed to determine urinary excretion of the two metabolites after an 8-h exposure of male Wistar rats to 10, 50, 100, and 500 ppm 2,2'-DDE and to 50, 200, und 1,000 ppm vinyl chloride. A long-term study was conducted to investigate the possible carcinogenicity of 2,2'-DDE in male and female Sprague-Dawley rats following s.c. injections of 4.36 mumole and 13.1 mumole 2,2'-DDE in DMSO per week. The evaluation of tumor development in treated groups and controls were based on macroscopic inspection and histological examinations of the suspect organs and tissues. Analysis of the metabolites showed that HEMA excretion was much lower than the excretion of TdGA following the uptake of 2,2'-DDE, 2-chloroethanol and 2-chloroacetaldehyde diethyl acetal. Contrary to these, vinyl chloride uptake resulted in a higher urinary excretion of HEMA than TdGA. There was no appreciable increase in the number of tumors detected in 2,2'-DDE-treated animals when compared with untreated or DMSO-treated groups. Since irradiation of 2,2'-DDE with UV did not elevate mutagenic activity of the compound against Salmonella typhimurium TA100, the high mutagenicity of the compound found in a desiccator cannot be due to the liberation of mutagenic compounds produced under the influence of UV light.

Acetaldehyde↗
PubMed1986

The pentafunctional FAS1 gene of yeast: its nucleotide sequence and order of the catalytic domains.

FAS1, the structural gene of the pentafunctional fatty acid synthetase subunit beta in Saccharomyces cerevisiae has been sequenced. Its reading frame represents an intron-free nucleotide sequence of 5,535 base pairs, corresponding to a protein of 1,845 amino acids with a molecular weight of 205,130 daltons. In addition to the coding sequence, 1,468 base pairs of its 5'-flanking region were determined. S1 nuclease mapping revealed two transcriptional initiation sites; 5 and 36 base pairs upstream of the translational start codon. Within the flanking sequences two TATATAAA boxes, several A-rich and T-rich blocks and a TAG...TATGTT...TATGTT...TTT sequence were found and are discussed as transcriptional initiation and termination signals, respectively. The order of catalytic domains in the cluster gene was established by complementation of defined fas1 mutants with overlapping FAS1 subclones. Acetyl transferase (amino acids 1-468) is located proximal to the N-terminus of subunit beta, followed by the enoyl reductase (amino acids 480-858), the dehydratase (amino acids 1,134-1,615) and the malonyl/palmityl transferase (amino acids 1,616-1,845) domains. One major inter-domain region of about 276 amino acids with so far unknown function was found between the enoyl reductase and dehydratase domains. The substrate-binding serine residues of acetyl, malonyl and palmityl transferases were identified within the corresponding domains. Significant sequence homologies exist between the acyl transferase active sites of yeast and animal fatty acid synthetases. Similarly, a putative sequence of the enoyl reductase active site was identified.

Amino Acid Sequence↗
PubMed1986

[Intraoperative rapid biopsy of thyroid neoplasms and surgical procedures in atypical adenoma].

For a differential diagnosis of atypical adenoma and highly differentiated follicular carcinoma cryosections are of value only if findings are positive. Between 1977 and 1982 we observed 85 thyroid carcinomas and 47 atypical adenomas. In 5 cases the diagnosis on the basis of a cryosection had failed to detect a carcinoma. In patients with atypical adenoma we performed a subtotal resection; a primary lobectomy was not carried out as it would have meant exposing an unnecessarily high percentage of patients to an increased risk of complications. 3-8 years postoperatively the patients show no pathological findings.

Adenoma↗
PubMed1986

Endogenous lipoproteins modify the thromboxane formation capacity of platelets.

A significantly negative correlation was demonstrated between HDL-cholesterol levels of serum and the thromboxane B2 (TXB2) formation in clotted whole blood, whereas a significantly positive correlation was estimated between the LDL cholesterol or apolipoprotein B (apo B) levels and the TXB2 formation in clotted whole blood. Similar relationships were observed between the HDL and apo B serum levels and the thrombin-induced malondialdehyde formation in platelet-rich plasma. The levels of HDL2 cholesterol, total cholesterol, apo A-I and of triglycerides were not significantly correlated with the TXB2 or malondialdehyde formation in both systems. The results in this study support the hypothesis that the TXB2 formation may be modulated by endogenous lipoproteins: high level of LDL stimulates and high level of HDL inhibits the TXB2 formation.

Adult↗
PubMed1986

Cow milk protein antigens and antibodies in serum of premature infants during the first 10 days of life.

Antigenic beta-lactoglobulin and alpha-casein were measured in the sera of 45 formula-fed infants of 31 to 41 weeks of gestation at 5 days and at 10 days of age. Quantitation was performed by a sensitive ELISA inhibition assay. On day 5 of life antigenic lactoglobulin was detected in 14 of 19 infants of less than 37 weeks gestation, but in only one of 10 infants of more than 36 weeks gestation. On day 10 of life the sera of all infants contained antigenic lactoglobulin. In contrast, on day 5 antigenic casein was present in four of 17 infants of less than 37 weeks gestation, but in 10 of 12 infants of the more mature group. On day 10 casein was detected in seven of 28 infants, with no difference between groups; anti-casein was found in eight of 12 infants. Infants of less than 37 weeks gestation have different absorption patterns than more mature infants do. "Gut closure" is an unlikely explanation for these findings.

Animals↗
PubMed1986

Aster-free spindle poles in insect spermatocytes: evidence for chromosome-induced spindle formation?

Tipulid spermatocytes form normally functioning bipolar spindles after one of the centrosomes is experimentally dislocated from the nucleus in late diakinesis (Dietz, R., 1959, Z. Naturforsch., 14b:749-752; Dietz, R., 1963, Zool. Anz. Suppl., 23:131-138; Dietz, R., 1966, Heredity, 19:161-166). The possibility that dissociated pericentriolar material (PCM) is nevertheless responsible for the formation of the spindle in these cells cannot be ruled out based on live observation. In studying serial sections of complete cells and of lysed cells, it was found that centrosome-free spindle poles in the crane fly show neither pericentriolar-like material nor aster microtubules, whereas the displaced centrosomes appear complete, i.e., consist of a centriole pair, aster microtubules, and PCM. Exposure to a lysis buffer containing tubulin resulted in an increase of centrosomal asters due to aster microtubule polymerization. Aster-free spindle poles did not show any reaction, also indicating the absence of PCM at these poles. The results favor the hypothesis of chromosome-induced spindle pole formation at the onset of prometaphase and the dispensability of PCM in Pales.

Animals↗