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Biomedical subjects

H Günther

Publications and source records attributed to H Günther.

At least 55 records · Page 3Linked to original sources
PubMed1987

Structure and electrochemistry of oxidoreductases.

The principles on which Nature has developed multifunctional redox centres, covering a large range of potentials, protected from water and oxygen and surrounded by highly specific proteins, are demonstrated. Structures and accessibilities of the active sites of iron-sulphur proteins, sulphur proteins, flavoproteins, cytochromes and copper proteins are correlated with their possibilities and modes of electron exchange with natural partners, artificial mediators and (modified) electrodes. The participation of charge-transfer and tunnelling processes in electron transport is demonstrated, and a suitable relative orientation of the partners is recognized as one of the most important requirements for electrochemical communication between large molecules and electrodes. The use of specifically modified electrode surfaces, for example those based on electroconductive polymers, is proposed as one of the aspects of future developments for direct electron transfer to proteins.

Cytochromes↗
PubMed1987

Mitochondria catalyze the reduction of NAD by reduced methylviologen.

Mitochondria from beef heart and yeast catalyze the reduction of NAD to NADH at the expense of reduced methylviologen (MV+). Based on protein the specific activity of mitochondria for this reaction is about 10 20-times higher than the consumption of oxygen in the presence of succinate or NADH. In 2H2O buffer (4S)-[4-2H]NADH is formed in high enantiomeric excess if the reduced methylviologen is electrochemically regenerated.

Animals↗
PubMed1987

Disturbed urinary transport in the pelvi-calyceal system in calcium-oxalate stone patients.

This study is intended to elucidate the process of urinary transport through the pelvi-calyceal system (PCS). PCS-motility of a total of 28 PCS was qualitatively and quantitatively determined in 9 stone patients and 14 control persons by examination of contrast medium excretion. From X-ray videograms recorded by means of Siemens urography, four different urinary transport types could be distinguished as well as the duration of the contraction periods and the intervals between the PCS-contractions. In stone patients physiological types of urinary transport are less common (33%) than in control subjects (81.25%). In stone patients the PCS is often characterized by reduced or even absent motility. Calyceal reflux is usually found in the systolic phase of PCS-contractions, which may apparently be regarded as a physiological process.

Biological Transport↗
PubMed1987

[Child development following severe intrauterine growth retardation--results of follow-up studies].

94 prenatally severely dystrophic newborn (year of birth: 1970 to 1982) of the Department of Gynaecology of the University of Cologne were catamnestically investigated when they 2 to 12 years of age; follow-up examinations were performed by paediatricians, neurologists, EEG specialists and by test psychology. In more than one-half of the children followed up in this manner delays in early childhood development were seen; there were no conspicuous differences between the two groups (classified according to years of birth). On comparing the age brackets 1970-1975 and 1976-1982 about one-third of the children in both groups presented at follow-up clearly evident signs of retarded growth. In 32% of the children born between 1970 and 1975 mostly mild neurological deficits or slight impairments of nerve function were observed, whereas in the 1976-1982 group this figure was 26%. The incidence of cerebral pareses was 7% and 9%, respectively. Disturbances of fine motor response were most frequently seen. Mild to moderate EEG changes occurred in both patient groups at about the same rate of incidence (34% and 32% respectively); one child in each group presented with definitely pathological electroencephalographic findings. Pathological test psychology results were seen in 38% (1970-1975) and 21% (1976-1982) of the followed-up children; the tests employed were the Göttingen form reproduction test in children born between 1970 and 1975 and the Denver development test in the younger children born between 1976 and 1982.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Height↗
PubMed1987

[Chronic pneumonia in a cohort of a thoracic surgery department].

Report on 78 cases of chronic pneumonia which underwent surgical treatment between 1959 and 1985. In 52 cases previous to operation a tumor was diagnosed or suspected (in 20 cases cytologically or histologically, and in 32 cases clinically, by x-ray or by endoscopy). The frequency and correlation of x-ray and endoscopic findings, problems of preoperative diagnostics, surgical methods and postoperative course are described.

Adolescent↗
PubMed1986

[Determination of enzyme activities in urine of patients with calcium oxalate calculi].

The catalytic activity of lactate dehydrogenase, gamma-glutamyltransferase, alkaline phosphatase, alanine aminopeptidase and N-acetyl-beta-D-glucosaminidase has been measured in 24 h urines of patients with a calcium oxalate calculus (9 men, 11 women) and has been compared with those of a reference collective (11 men, 10 women). The diagnostic sensitivity and the diagnostic specificity have been calculated according to four different discrimination methods in which the diagnostic sensitivity lies between 65% and 100%, the diagnostic specificity between 72% and 100%. Within the reference group there was a correlation between the excretion of the three brush-border enzymes, whereas within the group of patients only a correlation between gamma-glutamyltransferase and N-acetyl-beta-D-glucosaminidase was observed. From this pathophysiological conclusions can be drawn.

Acetylglucosaminidase↗
PubMed1986

Electron microscopic visualization of the capsule of Pasteurella multocida.

The results of electron microscopic visualization of capsules of Pasteurella multocida by means of negative staining and section methods are described. Using ruthenium red or a complex of platinum in negative staining, relatively homogeneous capsules were visualized, using alcian-blue, coarse-fibrous structured capsules appeared. The incubation with antiserum partially revealed narrow capsule zones in the sections. Ferritin-linked IgG labelled amorphous material between the bacteria or floccular appendages on the bacterial surface. Gold-linked Con A deposited on thick cord structures, on loose material between the bacteria and sometimes on their cell wall.

Cell Wall↗
PubMed1985

Chiral products from non-pyridine nucleotide-dependent reductases and methods for NAD(P)H regeneration.

Enoate reductase (EC 1.3.1.31) from a Clostridium tyrobutyricum strain catalyses the stereospecific reduction of many different alpha, beta-unsaturated carboxylates, aldehydes and even some ketones. The enzyme accepts electrons from NADH and, 1.5 times faster, from reduced methyl viologen (1,1'-dimethyl-4,4'-bipyridinium). Another new type of non-pyridine nucleotide-dependent reductase has an extremely broad substrate specificity for 2-oxo-carboxylates and 2-oxo-dicarboxylates. In crude extracts from Proteus mirabilis and Proteus vulgaris, specific activities of 2-12 mumol product formed per mg protein per min can be found when reduced methyl or benzyl viologen is used as electron donor. The products are (2R)-hydroxy acids. Enoate reductase and 2-oxo-carboxylate reductase are suitable for electro-enzymic reductions in which catalytic amounts of viologens are continuously reduced in an electrochemical cell. This procedure has three advantages: (1) regeneration of NAD(P)H by a second enzyme and substrate is not required, (2) the unstable pyridine nucleotides are not required in the reaction mixture, and (3) the rate of the reaction can be observed continuously by measuring an electric current. Several yeasts, as well as aerobic and anaerobic bacteria, catalyse the reduction of NAD(P)+ by reduced methyl viologen. Such cells can be used for electro-microbial reductions when only pyridine nucleotide-dependent reductases are present. Information about the enzymes which catalyse the reduction of NAD(P)+ at the expense of reduced methyl viologen is given.

Alcohol Oxidoreductases↗
PubMed1985

Hemolytic activity of Serratia marcescens.

A cell-bound hemolytic activity was found in several strains of Serratia marcescens. One Serratia cell per ten erythrocytes was sufficient to cause complete lysis of human erythrocytes within 2 h in the liquid assay. The hemolytic activity resided in the membrane fraction and could be inactivated by incubating cells with proteases. The hemolytic activity was greatly enhanced in actively metabolizing Serratia cells and was partially controlled by the iron supply. Hemolysis was accompanied by degradation of erythrocyte membrane proteins (band 3 and 6, glycophorin) and was independent of the blood group. The exoprotease secreted by S. marcescens in large amounts was not involved in hemolysis. Comparison with various hemolytic strains of Escherichia coli showed that hemolysis of erythrocytes was more pronounced with S. marcescens than with E. coli. In contrast to hemolysis by E. coli, lysis of erythrocytes by S. marcescens was not enhanced by Ca2+ ions.

Electrophoresis, Agar Gel↗