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Biomedical subjects

W Vogel

Publications and source records attributed to W Vogel.

At least 235 records · Page 13Linked to original sources
PubMed1995

Methanol in human breath.

Using proton transfer reaction-mass spectrometry for trace gas analysis of the human breath, the concentrations of methanol and ethanol have been measured for various test persons consuming alcoholic beverages and various amounts of fruits, respectively. The methanol concentrations increased from a natural (physiological) level of approximately 0.4 ppm up to approximately 2 ppm a few hours after eating about 1/2 kg of fruits, and about the same concentration was reached after drinking of 100 ml brandy containing 24% volume of ethanol and 0.19% volume of methanol.

Alcohol Drinking↗
PubMed1995

Serum neopterin concentrations in chronic liver disease.

Neopterin is produced by macrophages after stimulation with interferon gamma or lipopolysaccharide. Its production is increased in many infectious, autoimmune, and malignant diseases. The aim of this study was to examine whether, on the basis of neopterin as a marker, liver diseases could be classified according to aetiology and stage of disease. A cohort of 264 patients with chronic liver diseases (viral, metabolic, autoimmune, toxic) and 150 normal controls were studied; 136 of the patients had cirrhosis. Increased serum neopterin concentrations were found in 41% of all patients (controls 6.0 (2.2) nmol/l), with patients in the cirrhotic stage of disease showing higher neopterin values (mean (SD) 15.7 (23.6) nmol/ml) than those in the non-cirrhotic stage (9.9 (5.5)). There were no statistically significant differences in the serum neopterin concentrations that could be considered characteristic for different stages of disease classified according to the Child criteria. Such differences in concentrations of neopterin that were found in patients with liver diseases grouped according to underlying causes were only marginal. Serum neopterin concentrations were found to be significantly lower than in any other disease group only in patients with Wilson's disease. The results suggest that activated macrophages participate in the development of chronic liver disease. Measurement of serum neopterin does not offer a reliable method for differentiating between various aetiologies of chronic liver diseases and does not help to predict severity of cirrhosis.

Biopterins↗
PubMed1995

Necrotizing vasculitis associated with hepatitis C virus infection: successful treatment of vasculitis with interferon-alpha despite persistence of mixed cryoglobulinemia.

Type II cryoglobulinemia may be associated with chronic hepatitis C virus (HCV) infection and may be characterized by vascular purpura. We report on a case of histologically proven necrotizing vasculitis associated with type II cryoglobulinemia and HCV infection. Within 14 days of interferon-alpha therapy (3 x 3 million IU/ml/week), purpuric skin lesions disappeared as well as fatigue and arthralgia; 9 months after initiation of therapy, liver enzyme values were nearly normal despite persistence of HCV RNA tested by PCR and mixed cryoglobulinemia. Rheumatoid factor activity, however, decreased markedly. To our knowledge, our patient is the first reported case with histologically proven necrotizing vasculitis with a beneficial effect of interferon-alpha. Because of the persistence of cryoglobulins, but reduction of the IgM fraction in the cryoglobulin complex under interferon-alpha treatment, it would seem worthwhile to further elucidate the pathogenic role of qualitative instead of quantitative changes of cryoglobulins and the mechanism of action of interferon-alpha.

Arthralgia↗
PubMed1995

Prognosis and life expectancy on alpha-1-antitrypsin deficiency and chronic liver disease.

BACKGROUND: Alpha-1-antitrypsin deficiency is a common autosomal recessive disorder associated with early development of emphysema, liver cirrhosis, and hepatocellular carcinoma. The aim of the present study was to define prognosis and life expectancy in patients with alpha 1-antitrypsin deficiency with and without chronic liver disease. METHODS: After a follow-up of 15 years the estimated life table analysis of mortality of 160 patients with alpha 1-antitrypsin deficiency was retrospectively calculated. The survival time was estimated using the Kaplan-Meier survival curves and was compared with the life expectancy of the age- and sex-matched population of west Austria. RESULTS: Fifty-four patients with alpha 1-antitrypsin patients had evidence of chronic liver disease; of these, 78% showed positive viral markers. Of the 106 patients with alpha 1-antitrypsin deficiency without chronic liver disease none had evidence of additional viral infection. Life expectancy in patients with alpha-1 antitrypsin deficiency and chronic liver disease was significantly lower than in patients with alpha 1-antitrypsin deficiency without chronic liver disease (p = 0.001). No difference in life expectancy in alpha 1-antitrypsin deficiency without chronic liver disease was found in comparison with that of the normal population. CONCLUSIONS: We suggest that in alpha 1-antitrypsin deficiency-associated chronic liver disease it is the high coinfection rather than the inborn error of metabolism itself that is responsible for a deterioration of life expectancy or for the poor prognosis of the disease.

Chronic Disease↗
PubMed1995

Effect of neurotropic virus infection on neuronal and inducible nitric oxide synthase activity in rat brain.

To elucidate the potential role of inducible nitric oxide synthase (iNOS) and neuronal constitutive nitric oxide synthase (cNOS) in the pathogenesis of virus-induced encephalopathy, the activities of both NOS isoforms were determined in the brains of rats infected with Borna disease virus (BDV) or rabies virus. iNOS activity strongly increased, whereas neuronal cNOS activity significantly decreased in a time-dependent manner after either BDV or rabies virus infection. Choline acetyltransferase activity in the brain remained unchanged during both virus infections, suggesting that the decrease in cNOS activity does not reflect a generalized neuronal loss. Immunohistochemistry and Northern blot analyses indicate that the decrease in neuronal cNOS activity is due to a decrease in cNOS protein and mRNA synthesis. These results suggest that both an excessive generation of NO by activated macrophages or microglia, as well as a decrease of NO production in neurons may contribute to the neuropathogenesis of neurotropic virus infections.

Animals↗
PubMed1995

Kringle 4 of human apolipoprotein[a] shares a linear antigenic site with human catalase.

Monoclonal antibody (mab) 1A2, directed against human apolipoprotein[a] (apo[a]), revealed a strong reaction with peroxisomes as shown by immuno-gold labeled cryosections of human liver biopsies. This reactivity was not due to the presence of apo[a] in peroxisomes but to a cross-reactivity of mab 1A2. Immunoblot analysis of peroxisomal fractions and purified human catalase demonstrated that mab 1A2 reacts with catalase. Conversely, an anti-catalase antibody also recognized apo[a]. By sequence comparison we identified a 4-amino acid motif (Y-Y-P-N) that is shared between the highly repetitive kringle 4 motif of apo[a] and the carboxy-terminal third of the peroxisomal marker enzyme catalase. No other identical sequences were identified in these proteins. Results from the following experiments indicated that 1A2 recognizes this short linear epitope. i) Mab 1A2 reacted only with the 4 amino acid peptide sequence in a pin-ELISA using immobilized overlapping peptides. ii) A synthetic peptide including this sequence completely inhibited the 1A2 immunoreactivity to apo[a] and catalase. iii) A recombinant fusion protein tagged with the putative epitope was recognized by mab 1A2. Our findings demonstrate that unknown linear epitopes in native proteins can be identified by sequence comparison between known proteins. The practical implication is that antibodies against apo[a] must be controlled for this cross-reactivity before using them for immunohistochemical studies of intracellular apo[a] in tissues or cells.

Amino Acid Sequence↗
PubMed1995

A case of hepatocellular adenomatosis with a follow-up of 11 years.

Hepatocellular adenomatosis is characterized by the presence of numerous (arbitrarily > 10) adenomas within an otherwise normal liver without a history of glycogen storage disease or steroid hormone therapy. Although the disease is rare, its importance lies in its tendency to produce symptoms such as abdominal pain and its potential for abdominal hemorrhages. However, the prognosis of hepatocellular adenomatosis remains uncertain. Here we describe the case of a 40-yr-old female with hepatocellular adenomatosis without evidence of serious complications, who was observed over a period of 11 yr.

Adenoma, Liver Cell↗
PubMed1994

Na(+)-activated K+ channels localized in the nodal region of myelinated axons of Xenopus.

1. A potassium channel activated by internal Na+ ions (K+Na channel) was identified in peripheral myelinated axons of Xenopus laevis using the cell-attached and excised configurations of the patch clamp technique. 2. The single-channel conductance for the main open state was 88 pS with [K+]o = 105 mM and pS with [K+]o = 2.5 mM ([K+]i = 105 mM). The channel was selectively permeable to K+ over Na+ ions. A characteristic feature of the K+Na channel was the frequent occurrence of subconductance states. 3. The open probability of the channel was strongly dependent on the concentration of Na+ ions at the inner side of the membrane. The half-maximal activating Na+ concentration and the Hill coefficient were 33 mM and 2.9, respectively. The open probability of the channel showed only weak potential dependence. 4. The K+Na channel was relatively insensitive to external tetraethylammonium (TEA+) in comparison with voltage-dependent axonal K+ channels; the half-maximal inhibitory concentration (IC50) was 21.3 mM (at -90 mV). In contrast, the channel was blocked by low concentrations of external Ba2+ and Cs+ ions, with IC50 values of 0.7 and 1.1 mM, respectively (at -90 mV). The block by Ba2+ and Cs+ was more pronounced at negative than at positive membrane potentials. 5. A comparison of the number of K+Na channels in nodal and paranodal patches from the same axon revealed that the channel density was about 10-fold higher at the node of Ranvier than at the paranode. Moreover, a correlation between the number of K+Na channels and voltage-dependent Na+ channels in the same patches was found, suggesting co-localization of both channel types. 6. As weakly potential-dependent ('leakage') channels, axonal K+Na channels may be involved in setting the resting potential of vertebrate axons. Simulations of Na+ ion diffusion suggest two possible mechanisms of activation of K+Na channels: the local increase of Na+ concentration in a cluster of Na+ channels during a single action potential or the accumulation in the intracellular axonal compartment during a train of action potentials.

Animals↗
PubMed1994

Biologic activity of low dosage IL-2 treatment in vivo. Molecular assessment of cytokine network interaction.

The sequence of activation of the components of the cytokine network subsequent to in vivo application of different dosages of IL-2 is still poorly understood. Although side effects of IL-2 therapy are dose dependent, the dose-response relationship for induction of potentially beneficial or harmful cytokine genes still remains to be studied. We examined the patterns of cytokine gene expression after treatment of chronic hepatitis B patients with various doses of IL-2 in a phase 1 trial. Total RNAs were isolated from PBMC harvested at various time points after s.c. injection of natural IL-2 ranging from 30,000 to 1,000,000 U. Dose-dependent effects on mRNA expression of IL-2, GM-CSF, IFN-gamma, TNF-alpha, and IL-6 were assessed using Northern blotting and slot blotting techniques. A single application of 30,000 U nIL-2 induced selective and long-lasting expression of IL-2, IFN-gamma, and GM-CSF genes, which was not accompanied by accumulation of TNF-alpha and IL-6 mRNAs. Larger dosages of IL-2 induced activation of monokine genes and were associated with systemic side effects. mRNA levels of the different cytokines related to biologic activity and correlated with expression of specific proteins and cellular parameters: IL-2 mRNA with soluble IL-2R serum levels and induction of lymphopenia, GM-CSF mRNA with induction of neutrophilia, and IL-6 mRNA with c-reactive protein serum concentrations. Taken together these data indicate unexpected immunoregulatory activities of very low and nontoxic dosages of IL-2 in vivo.

Adolescent↗
PubMed1994

Deletions of Xq and growth deficit: a review.

A critical review of the literature disclosed 44 cases with a 46,X,Xq- karyotype without apparent mosaicism. Of these, 17 were of normal height (compared to the respective population), 11 had a height of over 1 SD below the mean, and 16 had a height of over 2 SD below the mean with breakpoints between Xq13 and Xq25. Since patients of normal height occurred with breakpoints as proximal as Xq13 we conclude that there is no major "growth gene" on Xq distal to q13. The most likely explanation for the variable phenotypic effect of Xq- is to assume that growth gene(s) in Xp or proximal Xq are inactivated on such a chromosome with some variability similar to the variable spreading of X inactivation seen in some X-autosome translocations.

Adolescent↗
PubMed1994

Activating effect of the flavonoid phloretin on Ca(2+)-activated K+ channels in myelinated nerve fibers of Xenopus laevis [corrected].

The effects of the flavonoid phloretin on K+ channels in amphibian myelinated nerve were studied by patch clamping. The open probability of Ca(2+)-activated K+ channels was greatly increased by external phloretin (10-200 microM) due to a shift of the membrane potential for half-maximal activation, E50, of -63.9 mV (80 microM phloretin). Open times were prolonged and closed times shortened. Channel activation by phloretin developed slowly (tau on = 33.4 s) and its washout was even slower (tau off,1 = 4.7 and tau off,2 = 183.2 s). In contrast, submillimolar phloretin blocked two delayed rectifier K+ channels (I and F) whereas the gating of the ATP-sensitive and the flickering K+ channel were unaffected. Phloretin may directly affect the voltage sensor of K+ channels.

Adenosine Triphosphate↗
PubMed1994

The acute-phase protein alpha 1-antitrypsin inhibits growth and proliferation of human early erythroid progenitor cells (burst-forming units-erythroid) and of human erythroleukemic cells (K562) in vitro by interfering with transferrin iron uptake.

We have previously shown that the hepatic acute-phase protein alpha 1-antitrypsin (alpha 1-AT) inhibits transferrin (tf) binding to its receptor (tfR) of human placental membranes. To evaluate the possibility that this interaction can explain the pathophysiology of the changes in iron metabolism in the course of chronic disease, subsequently leading to anemia in chronic disease (ACD), we examined the effect of alpha 1-AT on cells of the erythroid cell line. alpha 1-AT completely prevented tf binding to tfR on K562 human erythroleukemic cells and on reticulocytes. This inhibitory potency was dose-dependent and competitive, as proved in equilibrium saturation and kinetic studies. The cytokines interleukin-1 (IL-1), IL-6, and tumor necrosis factor alpha showed no such effect. Internalization of the tf-tfR complex was inhibited with alpha 1-AT in a dose-dependent manner. Furthermore, alpha 1-AT profoundly reduced the growth of K562 cells as well as their proliferation, albeit to a lesser degree. Growth of early erythroid progenitor cells (burst-forming units-erythroid) was significantly suppressed by alpha 1-AT, but no effect on the growth of late erythroid progenitor cells (colony-forming units-erythroid) was detected. These inhibitions of alpha 1-AT were seen in high physiologic concentrations attained in the course of acute-phase situations. These data show that alpha 1-AT might be a mediator of the changes in iron metabolism that are characteristic of clinical findings in the course of ACD.

Acute-Phase Proteins↗
PubMed1994

Decreased beta-endorphin content in peripheral blood mononuclear leukocytes from patients with Crohn's disease.

Increased activation of lymphocytes in inflammatory bowel disease is reflected by alterations of various immunological functions including enhanced spontaneous secretion of rheumatoid factor by mononuclear cells. since in rheumatic diseases increased secretion of rheumatoid factor is associated with decreased levels of beta-endorphin in circulating blood mononuclear leukocytes, we investigated levels of leukocyte beta-endorphin in inflammatory bowel disease and compared them with those in hepatobiliary disorders and in healthy subjects. Levels of beta-endorphin were measured in extracts from peripheral blood mononuclear leukocytes by radioimmunoassay. beta-Endorphin levels ranged from 0 to 67 pg/10(6) cells. Mononuclear leukocytes from ulcerative colitis patients contained as much beta-endorphin as those from healthy control subjects. In patients with Crohn's disease, levels of beta-endorphin were reduced by as much as roughly 50%. An inverse relationship was found between leukocyte beta-endorphin on the one hand and erythrocyte sedimentation rate, blood granulocyte or thrombocyte counts, and C-reactive protein levels in plasma on the other. In patients with various hepatobiliary disorders including fatty liver disease, viral hepatitis, primary biliary cirrhosis, and cryptogenic or alcoholic cirrhosis, beta-endorphin levels were not significantly different from the normal range values. Data indicate that leukocyte beta-endorphin may be involved in regulation of the systemic inflammatory activity of Crohn's disease.

Adult↗