Showing papers by "University of Düsseldorf published in 1979"

Effect of physical training on glucose tolerance and on glucose metabolism of skeletal muscle in anaesthetized normal rats

Abstract: The effect of physical training on glucose tolerance in vivo and skeletal muscle glucose metabolism in vitro was investigated in normal rats. Treadmill running for 10 days up to 240 min/day led to a decrease of basal and glucose-stimulated plasma insulin levels without major alterations of the IV glucose tolerance (1 g/kg body weight). Swim training of two weeks' duration, i. e. exercise up to 2×75 min/ day, which did not induce significant changes in body composition, skeletal muscle glycogen levels or citrate synthase activity, resulted in a significant improvement of IV glucose tolerance and substantial reductions of basal and glucose-stimulated plasma insulin levels. Associated with this apparent improvement of insulin sensitivity in vivo, significant increases of the insulin-stimulated glucose uptake (+ 55%) and lactate oxidation (+ 78%) in vitro were found on perfusion of the isolated hindquarter of swim-trained animals. It is suggested that mild physical training can improve glucose tolerance and insulin sensitivity in normal rats, at least in part, due to an increase of insulin sensitivity of skeletal muscle glucose metabolism.

Differential effects on learning by ventromedial vs lateral hypothalamic posttrial injection of substance P.

Abstract: The effects of post-trial injection of substance P (SP) into the lateral hypothalamus (LH) and the ventromedial hypothalamus (VMH) on passive avoidance learning was studied in rats. In the VMH, 50 ng and 500 ng SP influenced neither learning of a step-down avoidance nor of an alcove avoidance response. In contrast to these findings, 500 ng SP injected into the LH significantly enhanced retention of the alcove avoidance task. Similarly, in the step-down avoidance experiment, learning was strongly facilitated by posttrial injection of 50 ng as well as 500 ng SP into the LH. These results, together with our previous data showing amnesia with posttrial injection of SP into amygdala and substantia nigra, suggest that exogenously applied SP influences the activity of those brain regions shown to contain high densities of SP-positive nerve terminals. Interestingly, the effects of posttrial SP injection parallel the effects of post-trial electrical brain stimulation on passive avoidance learning. Hence, posttrial SP retroactively facilitates or impairs depending on where in the brain it is injected.

Hypothermia-induced potentiation of histamine H2-receptor-mediated relaxation and cyclic AMP increase in the isolated mesenteric artery of the rabbit.

Abstract: On helically cut strips of the rabbit's mesenteric artery, a temperature decrease from 42°C to 25°C reduced the contractile responses to histamine. Metiamide shifted the dose-response curve of the histamine-induced contraction towards higher values at 25°C, but not at 42°C. Furthermore, on arterial strips contracted by phenylephrine histamine evoked a dose-dependent relaxation at 25°C whereas at 42°C only slight relaxing responses to histamine occurred. Metiamide was capable of preventing the relaxation induced by histamine in a competitive manner. At 25°C the relaxation as produced by histamine was accompanied by increases in cyclic AMP which occurred prior to the relaxing effects. Metiamide abolished the cyclic AMP increase in response to histamine. At 42°C histamine was unable to elevate the cyclic AMP content. Thus, it is concluded that a cyclic AMP-mediated relexation due to stimulation of H2-receptors counteracts the histamine-induced contraction and reduces the contractile responses to histamine at low temperatures. In addition, clear-cut evidence exists from the present study that also on artery smooth muscle the H2-receptor-mediated responses are closely associated to cyclic AMP.

Incidence of epithelial dysplasia after partial gastric resection.

Abstract: Because of the higher risk of cancer in the gastric stump, an increased incidence of pre-cancerous conditions should be exspected also in the resected stomach. Therefore, a combined endoscopic and bioptic study was performed in order to investigate the incidence of dysplasias in the gastric stump after resection for benign conditions. Among 101 patients with gastric resection, 2 cases were excluded from this study because of preceeding gastric cancer and one because of cancer of the gastric stump. In 43 of the remaining 98 patients, a Billroth-I-resection (gastroduodenostomy) had been carried out. In the remaining 55 patients with a Billroth-II-resection (gastroenterostomy) 9 had an additional enteroanastomosis of Braun whereas in the residual 46 patients this enteroanastomosis was lacking. This distinction was made because of a facultative or obligatory bile reflux. The average age of the B-I-group was 68 years, of the B-II-group with enteroanastomosis 69 years, and the B-II-group without enteroanastomosis 62 years. A non-operated group matched for age served as control group. Biopsy particles from the anastomotic region were gained by endoscopy and cut in step sections. The classification of dysplasias (degree I-III) followed the criteria given by Nagayo as modified by Grundmann. Inflammatory reactive changes were separated from these. A few changes could not be classified definitely and were listed as unclassified dysplasia. While dysplastic changes of low degree were quite numerous in every group, the dysplasias of higher degree were only found in a small number of cases. In the 46 cases with B-II-resection without Braun's enteroanastomosis, there were 5 dysplasia II and 3 dysplasia II. In the 9 cases with B-II-resection and with Braun's enteroanastomosis, there was 1 dysplasia I and no dysplasia III. In the 43 patient with B-I-resection only 2 dysplasia II and no dysplasia III were found. In the control group of 98 patients matched for age there were only 5 cases with dysplasia I and 1 case with dysplasia III. Patients with higher degrees of dysplasia showed a higher age and a longer interval after operation. There was also a correlation between higher degrees of dysplasia and severe atrophic changes in the mucosa. Correlating the degree of dysplasia with the reason for gastric resection, most of the dysplastic changes occurred in patients resected for gastric ulcer, whereas cases resected for duodenal ulcer showed only 2 dysplasias I. The discussion refers to the few data about dysplasia of the gastric stump available from the literature. Atrophic and increased regenerative changes obviously play a role in the pathogenesis of these dysplastic changes. As a causative factor the role of bile reflux is discussed. A further diagnostic and therapeutic regimen for the different forms of dysplasia is proposed.

Clinical, morphological, and biochemical investigations on a patient with an unusual form of neuronal ceroid-lipofuscinosis.

Abstract: A patient with a progressive neurological disorder beginning at the age of three years is described. Mental and visual disturbances were the first signs, soon followed by ataxia and myoclonic jerks. Fundoscopy revealed a decreased pigmentation of the retina. Ultramicroscopic investigations of muscle and skin disclosed the typical changes seen in the late infantile and juvenile forms of neuronal ceroid-lipofuscinosis. In contrast to the clinical and ultrastructural findings, the fatty acid pattern of the serum lecithin showed a significant increase of arachidonic acid and a corresponding decrease of linoleic acid which is characteristic of the so-called infantile form of neuronal ceroid-lipofuscinosis (Hagberg-Santavuori variant; polyunsaturated fatty acid lipidosis). The obvious heterogeneity of the clinical, histological and laboratory findings within the subgroups of neuronal ceroid-lipofuscinosis is briefly discussed.

Detection of HBsAg containing cells in liver biopsies by different stains and classification of positively reacting ground-glass hepatocytes.

Abstract: The diagnostic significance of orcein, aldehydthionine, and chromotrope anilinblue stains for the demonstration of HBsAg containing hepatocytes was investigated in 602 unselected liver biopsies. Five types of specifically stained ground-glass hepatocytes (GGH) were distinguished: Type I showed a positive staining reaction of the cytoplasmic periphery (marginal GGH), type II a diffuse staining of the total cytoplasm (diffuse GGH). Type III contained round or oval globular positive cytoplasmic masses (globular GGH). Type IV showed only very small round, drop-like or sickle-shaped positive structures (spotty GGH). The GGH with fatty changes were designated as type V. In all carriers and patients with minimal hepatitis GGH, mostly type I and II, appeared in extensive clusters within the lobules. In chronic persistent hepatitis, there were moderately numerous, partly grouped, partly disseminated ground-glass hepatocytes of type II and III. In chronic active hepatitis there were only a few GGH of type IV. In acute viral hepatitis, there were no typical GGH, however, positively stained phagocytes were seen. The intracellular antigen localization and the intralobular distribution of GGH are considered to be the result of an immune reaction. Single so-called 'metabolic' GGH sometimes showed similar pictures. However, they could usually be distinguished from virus containing GGH because of their granular cytoplasmic structure and a lower staining intensity in the applied stains. Among the three stains the orcein stain yielded the best results. In some cases with HBsAg-positive chronic active hepatitis virus infection could not be proved by means of staining.

Clinical and morphological studies of pineal tumours

Abstract: This is a report of clinical, morphological, diagnostic, endocrinological and therapeutical experiences with 18 patients with tumours in the pineal region. The histological diagnosis was verified in four cases by autopsy, in seven cases by biopsy, and in one case by microscopical verification of tumour cells in the CSF. In all biopsy cases we are dealing with typical germinomas. In the other clinical cases diagnosis was made by neuroradiological and endocrinological methods. The localization was possible by encephalotomography or CT scan, according to Kageyama. Particular attention was given to the endocrinological dysfunctions which originate in the hypothalamus. Also the hypothalamic dysfunctions after irradiation were discussed. Since the results of primary surgical approach and biopsy have been unsatisfactory, we preferred a non-operative schedule for treatment of pineal tumours.

Regulation of the photosynthetic carbon cycle, phosphorylation and electron transport in illuminated intact chloroplasts

Abstract: pH-Control of the Carbon Cycle . On illumination, chloroplasts pump protons from the stroma not only into the thylakoid compartment, but also across the chloroplast envelope into the extra-chloroplast space. Increased proton back leakage from a neutral medium into the stroma as mediated by some salts of weak acids inhibited photosynthesis, and inhibition was strongly pH-de-pendent. It was caused by acidification of the stroma which inactivated fructose and sedoheptulose bisphosphatases. The stroma pH controlled not only activity, but also light-activation of fructose bisphosphatase, thus amplifying pH-control of photosynthesis. Light-activation of glyceraldehydephosphate dehydrogenase (NADP) and of malic dehydrogenase (NADP) was also sensitive to pH, while activation of phosphoribulokinase did not respond to salts that caused stroma acidification only. However, with potassium nitrite which decreases the stroma pH and also oxidizes ferredoxin activation became pH-dependent. Fructose bisphosphatase, phosphoribulokinase and malic dehydrogenase remained in the activated state when the stroma pH was decreased in the light, while light-activation of glyceraldehydephosphate dehydrogenase was reversed at a decreased stroma pH.

Calculation of the spin density and spin-spin dipolar interaction in the triplet state of metal porphins

Abstract: The spin density and zero-field splitting (ZFS) of the lowest triplet state of a light metal porphin are determined by means of a Pariser-Parr-Pople ground state SCF π-electron MO-calculation with CI. Only the pz -orbitals of the carbon and nitrogen atoms are considered. The semi-empirical values of the integrals involving nitrogen orbitals are varied between the values commonly used for pyrrole and pyridine-type nitrogen. The two lower triplet states (corresponding to the excitations 3(eg ←a 2u ) and 3(eg ←a 1 u ) in Gouterman's four orbital model) are considered, both for a b 1g and a b 2g the spin densities determined by McLachlan's extended Hartree-Fock method lead to a perfect explanation of the hyperfine structure observed for zinc porphin and magnesium porphin in n-octane. The ZFS parameters are calculated by a semi-empirical method; satisfactory agreement with experiment is obtained only if the CI expansion is truncated at the point where the weight of the individual configurations becomes less th...

Cutaneous cytochrome P-450 activity during hexachlorobenzene-induced experimental porphyria in rats.

Abstract: The human population is exposed to a wide variety of insecticides, drugs, fungicides, and other environmental chemicals. Most of these xenobiotics are metabolized by membrane-bound, mixed function oxidases, which require NADPH/NADH and molecular oxygen. This oxidative metabolic step is mostly a hydroxylation, catalyzed by enzyme systems involving the CO-sensitive terminal monooxygenase cytochrome P-450. Cytochrome P-450 is a multicomponent group of mixed function oxidases which shows its highest activity in the endoplasmatic reticulum of the liver; however other tissues such as kidneys, small intestine, lungs, brain, lymphocytes and skin also contain these enzymes (Ullrich and Kremers, 1977). Cutaneous cytochrome P-450 may be of considerable interest in the biotransformation of potentially toxic chemicals of the environment. On the other hand, the oxidative metabolism of various drugs by the skin cytochrome P-450 may lead to the formation of reactive metabolites which are often carcinogens, mutagens or cytotoxic agents. In view of the biological importance of the skin cytochrome P-450, we found it of interest to determine it's concentration and inducibility in rat skin microsomes during a long-time exposition to hexachlorobenzene (HCB). This chlorinated aromatic hydrocarbon is a world-wide distributed fungicide which has proved to be a potent inducer of the cytochrome P-450 in the liver of experimental animals (Stonard, 1975; Doss et al., 1976). Adult female Wistar rats (Zentralinstitut ftir Versuchstierzucht, Hannover, FRG), weighing about 200 g, were fed with a diet containing 0.05 % HCB over a period of 10 and 70 days, respectively. Wistar rats, kept under standard diet were used as controls. Ten and 70 days after the beginning of the HCB-application the animals were killed by decapitation and liver microsomes were prepared following the method of Kamath and Rubin (1972); liver microsomal cytochrome P-450 activity (expressed in terms of O-dealkylation of 7-ethoxycoumarin) was estimated using carbon monoxide, metyrapone, tetrahydrofurane and naphthoflavone as inhibitors (UU-

Relationship between histamine-induced changes of cyclic AMP and mechanical activity on smooth muscle preparations of the guinea-pig ileum and the rabbit mesenteric artery

Abstract: On guinea-pig ileum and rabbit mesenteric artery contracted by high potassium (100 mM) histamine produced relaxations which were inhibited by the H2-receptor antagonist metiamide. These results are thus indicative for the role of H2-receptors in mediating relaxation and for H1-receptors in mediating contraction on smooth muscle. Time course studies for the relaxing and cyclic AMP responses to histamine showed that the cyclic AMP increase preceded the H2-receptor mediated relaxation. The cyclic AMP increase in response to histamine was prevented by metiamide, but remained unaffected by mepyramine on both the guinea-pig ileum and the rabbit mesenteric artery. In addition, dose-response curves obtained on the mesenteric artery demonstrated that the H2-receptor mediated depressor responses coincided with cyclic AMP increases. Thus, these results gave clear-cut evidence that cyclic AMP is an intracellular metabolic event only implicit in the H2-receptor mediated relaxation, but not in the H1-receptor mediated contraction on smooth muscle preparations.

Eigenmode scattering relations for plane-stratified gyrotropic media

Abstract: We consider the 4×4 scattering matrixS for a plane wave incident on a plane-stratified gyrotropic multilayer slab, which is assumed to have a single symmetry axis (the magnetisation vector in a ferrite sheet, or the external magnetic field direction in a plane-stratified magnetoplasma). In the given (original) problem the plane of incidence is at an azimuthal angle ϕ with respect to the magnetic meridian plane (the plane containing the normal to the stratification, and the gyrotropic symmetry axis), and there is a corresponding “conjugate” set of wave fields, in which the plane of incidence is at an azimuthal angle (π−ϕ), with a corresponding conjugate scattering matrixS′. Adjoint wave fields, obtained by reversing the magnetic symmetry vector, are used to yield the eigenmode amplitudes required in the definition of the scattering matrices. At an interface between two adjacent layers the scattering matrices are shown to be uniquely determined by the characteristic wave polarisations, and this is used to prove that the given and conjugate scattering matrices,S andS′, for the overall multilayer system are mutually transposed, i.e.\(S = \tilde S'\).

Matrix representation of the kinetic theory differential operator

Abstract: A general scheme is given to determine the matrix representation of the differential operator of the kinetic theory of gas mixtures, i.e., the streaming operator in the one‐particle phase space. The matrix elements are evaluated explicitly for the Burnett basis functions and a Lorentz type external field. The density, temperature, and mean velocity are treated as field quantities in order to assure the applicability of the results to inhomogeneous problems.

Trituration and creep.

Abstract: Creep values of amalgam have been thought to be typical and nearly equal to their order of magnitude, depending on composition and particle shape. Recently it has been shown that trituration time may cause changes in creep magnitudes. The type of mixer and its frequency have contributed additional variabilities. These variations could not be related consistently to changes in creep values. Increases in condensation pressure did contribute to more predictable and constant values found with different mixing times.

Mutagenicity of 8-ethoxycaffeine in vitro: Induction of point mutations in the salmonella/microsome test and of sister-chromatid exchanges as well as chromosomal aberrations in Chinese hamster ovary cells (CHO line)

Abstract: The caffeine derivative 8-ethoxycaffeine (EOC) was tested in 3 different test systems in vitro. Each experiment was carried out with and without S9 mix. Incubation temperatures were 20 and 37dgC. 1. (1) In the Salmonella/microsome test, EOC behaved as a pro-mutagen in the Salmonella typhimurium strain TA1535. No mutagenic activity was found in experiments without S9 mix. The influence of temperature was negligible. The mutagenic activity of EOC depended mainly on the mammals used to prepare the S9 fraction and on the agents given to them to induce liver enzymes. 2. (2) EOC did not induce sister-chromatid exchanges in cell cultures, either at 20 or at 37°C. 3. (3) On the other hand, EOC induced chromosomal aberrations when the cells were incubated at 37°C without S9 mix.