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Biomedical subjects

M Huber

Publications and source records attributed to M Huber.

At least 253 records · Page 14Linked to original sources
PubMed1989

Cerebral glucose metabolism in the course of subacute sclerosing panencephalitis.

Regional cerebral glucose metabolism was studied in a 15-year-old boy with subacute sclerosing panencephalitis before and after therapy with human interferon beta, using positron emission tomography of fluorine 18-2-fluoro-2-deoxyglucose. At first examination, metabolism was symmetrically decreased in the thalamus, cerebellum, and all cortical areas except prerolandic motor cortex, but increased in lentiform nucleus. A computed tomographic scan was normal. Six months later, bilateral focal necrosis centered in the previously hypermetabolic putamen was demonstrated by computed tomography and magnetic resonance imaging. The caudate nucleus and the superoposterior part of the putamen were spared, still showing increased metabolism. Corresponding with some clinical improvement, cortical glucose consumption rates had returned to a normal level.

Adolescent↗
PubMed1989

Myelin basic protein in the cerebrospinal fluid of patients infected with HIV.

The major pathological abnormalities of HIV encephalopathy are infiltrates of macrophages, multinucleated giant cells, microglial nodules and demyelination. Elevated myelin basic protein (MBP) levels in the cerebrospinal fluid (CSF) provide a marker for central nervous system demyelination. The purpose of this study was to investigate the possible role of CSF MBP as a useful and early marker for HIV encephalopathy. The CSF of 40 consecutive patients with HIV infection of various clinical stages was investigated, including 13 patients with clinical signs of HIV encephalopathy. CSF MBP was elevated in 2 patients (5.0 and 5.3 ng/ml), both of whom had moderate to severe HIV encephalopathy. The course of the disease was rapid in both patients. In the remaining 38 patients, CSF MBP levels were marginally elevated (n = 12) or normal (n = 26). Our results suggest that CSF MBP is not a sensitive marker for the diagnosis and evaluation of HIV encephalopathy, but may be an indicator of prognosis for the course of the disease. There were only few findings of elevated CSF MBP levels in patients with HIV encephalopathy in the current study, and this may be because the disorder progressed slowly in most patients. It is possible that CSF MBP levels in HIV encephalopathy may only be elevated with acute clinical deterioration but are normal in slowly progressive forms of demyelination, as seen in multiple sclerosis.

AIDS-Related Complex↗
PubMed1989

Metabolic inactivation of leukotrienes.

The metabolic inactivation of the cysteinyl leukotrienes LTC4 and LTD4 and of the chemotactic LTB4 was studied in the rat in vivo and in hepatocyte suspensions, respectively. 1. Deactivation of LTC4 via LTD4 to LTE4 was a most active process in the blood circulation, catalyzed mainly by ectoenzymes located on the internal wall of blood vessels. Uptake of cysteinyl leukotrienes by hepatocytes and kidney cells contributed to the rapid elimination of these potent mediators whenever they were released into the blood circulation. The initial half-life of LTC4 in vivo was 12 seconds. 2. omega-Oxidation leads to the formation of omega-hydroxylated and omega-carboxylated cysteinyl leukotrienes which were detected in bile and urine. Biliary metabolites included those formed by stepwise beta-oxidative degradation of omega-carboxy-N-acetyl-LTE4, yielding the dinor, tetranor, and hexanor derivative. 3. The peroxisome proliferator clofibrate strongly increased the degradation of LTE4 by omega-oxidation and subsequent beta-oxidation in vivo. The generation of new polar metabolites was detected by HPLC methods and by the use of 3H8-labeled cysteinyl leukotrienes in comparison with the 3H2-labeled precursor. 4. The metabolic degradation and inactivation of cysteinyl leukotrienes in vivo and of LTB4 in isolated hepatocytes was potently inhibited by ethanol. The site of inhibition was the oxidation of omega-hydroxy-N-acetyl-LTE4 and of omega-hydroxy-LTB4 to the respective omega-carboxylated metabolite. This inhibition led to an accumulation of the biologically active LTB4 and of N-acetyl-LTE4. The interference of leukotriene inactivation in the liver may provide a novel explanation for the ethanol-induced inflammatory reaction in acute alcoholic liver disease.

Animals↗
PubMed1989

A placebo-controlled, double-blind crossover study of naltrexone hydrochloride in outpatients with normal weight bulimia.

The endogenous opioid system plays an important role in the control of feeding behavior. Previous research has shown that antagonism of endogenous opioids will suppress feeding in certain models in both human and infrahuman species. In the current study, 16 normal-weight bulimic women were treated with low-dose naltrexone, the long-acting, orally active narcotic antagonist, and placebo in a crossover design. The use of the active drug was not associated with a clinically significant reduction in binge eating or vomiting episodes. Suggestions for further research in this area are offered.

Adult↗
PubMed1989

Analysis of cysteinyl leukotrienes in human urine: enhanced excretion in patients with liver cirrhosis and hepatorenal syndrome.

The cysteinyl leukotrienes, comprising leukotriene C4 and its metabolites, are biologically most active mediators, eliminated from the blood circulation by the liver and the kidneys. The urine of normal subjects and of patients with hepatic and/or renal failure was analysed for endogenous cysteinyl leukotrienes. The leukotriene metabolites were separated by reversed-phase high-performance liquid chromatography and subsequently quantified by radioimmunoassay. Leukotriene E4 was detected in all urine samples analysed. Its mean concentration increased from 0.3 nmol l-1 in healthy subjects to 0.8 nmol l-1 in patients with liver cirrhosis. In patients with hepatorenal syndrome leukotriene E4 averaged 7.8 nmol l-1; in addition, N-acetyl-leukotriene E4 was detected in an average amount of 1.5 nmol l-1. The mean leukotriene E4/creatinine ratio in urine increased from 0.02 in healthy subjects to 0.11 in patients with liver cirrhosis and to 1.2 mumol leukotriene E4 mol-1 creatinine in patients with hepatorenal syndrome. These results indicate that cysteinyl leukotrienes may play an important role in the mediator network responsible for the development of the hepatorenal syndrome in patients with severe liver disease.

Adolescent↗
PubMed1989

DNA probes specific for Entamoeba histolytica possessing pathogenic and nonpathogenic zymodemes.

A number of DNA probes which hybridize to highly abundant DNA sequences of Entamoeba histolytica were developed. Variations in the hybridization patterns of different E. histolytica strains were detected with selected probes. Four types of restriction fragment length patterns were obtained. Of these, the first class belonged to E. invadens and E. histolytica-like var. Laredo. The next two classes consisted of various strains of E. histolytica which were originally isolated from symptomatic patients and possessed pathogenic patterns of isoenzymes (zymodemes), whereas the fourth group contained E. histolytica strains with nonpathogenic zymodemes obtained from asymptomatic carriers. DNA probes, based on DNA sequences specific to E. histolytica isolates with pathogenic and nonpathogenic zymodemes were isolated, and their nucleotide sequences were determined. These probes (P145 and B133) hybridized selectively to DNA of isolates possessing either pathogenic or nonpathogenic isoenzyme patterns. The newly developed probes could be useful for diagnostic purposes and could serve as tools to investigate the molecular basis of pathogenicity and the genetic mechanisms which regulate the variable aggressive behavior of the parasite.

Animals↗
PubMed1989

[Magnetic resonance tomography flow measurement in cerebral arteriovenous angioma].

A case of cerebral AVM associated with Klippel-Trenaunay Syndrome is presented where Magnetic Resonance (MRI) flow measurement revealed details of the shunt from the cerebral arterial system. The AVM was supplied by two arteries, the main flow came from the left vertebral and internal carotid artery. The arterial blood supply of the AVM was about 268 ml/min, the av-shunt flow was about 18% of the whole carotid and vertebral upstream flow.

Adult↗
PubMed1989

[Quantitative studies on the secretory output of the palatine salivary glands].

A method for the direct measurement of the secretory output of the palatine glands is described and its clinical reliability is verified in a study on 134 persons. The results showed that, if the measuring conditions are fulfilled and the measuring parameters are kept constant, the error remains below 15%. Situative influences, such as the time of the day, the date of the measurement, etc. are just of secondary importance for the measured results. The physiological secretory output of the palatine glands averages 1.36 microliters/mm2 mucosal surface, which is about 30 times as much as the values measured in patients with symptoms of hyposalivation. Personal characteristics of the persons tested such as age, sex, etc. have no major influence on the secretory output. Serial measurements during treatment with ptyalagogues supported the evidence that this measuring method is a valuable instrument in the diagnosis of salivation disorders.

Humans↗
PubMed1989

[Analysis of accidents in children in school, apprenticeship and agriculture].

A significant increase of accidents in children was the cause to look into the reasons. 516 children have been registered. We could show that the share of the severe injured patients was more than on an average. Over 42% of the injuries concerned the head and face, about a third the lower extremities and a quart the upper extremities. Some cases were demonstrated and discussed with state and development after the accident. The major part of the children had an accident on the way to school and back home. So the explanation of the dangers of the road will be extremely effective in prevention of road accidents.

Accidents↗
PubMed1988

Identification of two histidines as copper ligands in Streptomyces glaucescens tyrosinase.

The physiochemical properties of wild type and two mutants of Streptomyces glaucescens tyrosinase are reported. The native enzyme contains two coppers at the active site which are EPR nondetectable. The two coppers react stoichiometrically with one hydrogen peroxide molecule giving rise to oxytyrosinase. Its optical features are similar to those reported earlier for a molluscan hemocyanin. The two mutants in which histidine-62 and -189 were changed to asparagine by site-directed mutagenesis have lost their enzymatic activity and their ability to bind oxygen and contain only one copper ion which is fully EPR detectable. The EPR parameters indicate that the remaining copper is in a tetragonally distorted ligand environment. These data are in agreement with His-62 and His-189 serving as copper ligands in S. glaucescens tyrosinase.

Amino Acid Sequence↗
PubMed1988

Tumor necrosis factor alpha stimulates leukotriene production in vivo.

Tumor necrosis factor alpha, or cachectin (TNF), is a polypeptide mediator with proinflammatory and antitumor actions. It is produced in large amounts by lipopolysaccharide (LPS)-activated macrophages. TNF as well as LPS stimulated the arachidonate cascade leading to the synthesis of leukotrienes (LT) in vivo. Production of endogenous cysteinyl LT was measured in anesthetized rat using the biliary excretion of N-acetyl-LTE4 as an indicator. Infusion of TNF over a 1-h period greatly increased the rate of cysteinyl LT production during the subsequent 3 h. Pretreatment with anti-TNF antibody F(ab')2 fragments prevented enhanced LT generation as well as tachypnea (a sign of the in vivo action of TNF). LT production elicited by TNF was similar to that evoked by infusion of LPS. Our results indicate that lipoxygenase products are involved in the network of pathophysiological events induced by TNF. The proinflammatory and shock-inducing LT may mediate many of the adverse effects of TNF in vivo as well as its antitumor action.

Animals↗
PubMed1988

Intravenous natural beta interferon treatment of chronic exacerbating-remitting multiple sclerosis: clinical response and MRI/CSF findings.

A preliminary study is reported of clinical response and CSF/MRI findings in nine patients with multiple sclerosis receiving intravenous infusions of natural beta-interferon. The mean patient follow-up was for 1.2 years. Neither exacerbation rates nor CSF-IgG synthesis nor plaque formation as revealed by MRI showed a significant reduction during therapy. One patient developed a severe exacerbation of multiple sclerosis shortly after interferon infusion.

Adolescent↗
PubMed1988

Nucleotide sequence analysis of an Entamoeba histolytica ferredoxin gene.

A cDNA clone (subclone B) previously isolated from the human parasite Entamoeba histolytica was characterized. DNA sequence analysis of subclone B identified the DNA as that encoding apoferredoxin. E. histolytica ferredoxin cDNA contains unusually short 5' and 3' noncoding regions of 9 and 25 nucleotides, respectively. A genomic ferredoxin clone was isolated from E. histolytica DNA, and comparison of genomic and cDNA sequences revealed that the ferredoxin gene is unspliced. The deduced amino acid sequence of E. histolytica ferredoxin resembles clostridial type of ferredoxins, and shows an arrangement of cysteines characteristic for the coordination of 2[4Fe-4S] centres. Of interest is the absence of an aromatic amino acid in the N-terminal region of the protein, a feature which is conserved in clostridial ferredoxins. Southern blot analysis of three different E. histolytica strains (200:NIH, Rahman and HM-1:IMSS) demonstrated the presence of a family of at least two ferredoxin genes. One of these genes is marked by restriction length polymorphisms in different strains of E. histolytica.

Amino Acid Sequence↗