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Biomedical subjects

G Fuchs

Publications and source records attributed to G Fuchs.

At least 181 records · Page 10Linked to original sources
PubMed1978

Acetate assimilation and the synthesis of alanine, aspartate and glutamate in Methanobacterium thermoautotrophicum.

Cultures of the autotrophic bacterium Methanobacterium thermoautotrophicum were shown to assimilate acetate when grown on CO2 and H2 in the presence of acetate. At 1 mM acetate 10% of the cell carbon came from acetate, the rest from CO2. At higher concentrations the percentage increased to reach a maximum of 65% at acetate concentrations higher than 20 mM. The data suggest that acetate may be an important carbon source under physiological conditions. The incorporation of acetate into alanine, aspartate and glutamate was studied in more detail. The cells were grown on CO2 and H2 in the presence of 1 mM U-14C-acetate. The three amino acids were isolated from the labelled cells by a simplified procedure. Alanine, aspartate and glutamate were found to have the same specific radioactivity. Degradation studies showed that C1 of alanine, C1 and C4 of aspartate, and C1 and C5 of glutamate were exclusively derived from CO2, whereas C2 and C3 of alanine and aspartate, and C3 and C4 of glutamate were partially derived from acetate. These findings and the presence of pyruvate synthase, phosphoenolpyruvate carboxylase and alpha-ketoglutarate synthase in M. thermoautotrophicum indicate that CO2 is assimilated into the three amino acids via acetyl CoA carboxylation to pyruvate, phosphoenolpyruvate carboxylation to oxaloacetate, and succinyl CoA carboxylation to alpha-ketoglutarate.

Acetates↗
PubMed1978

Evidence for an incomplete reductive carboxylic acid cycle in Methanobacterium thermoautotrophicum.

The involvement of reactions of the tricarboxylic acid cycle in autotrophic CO2 fixation in Methanobacterium thermoautotrophicum was investigated. The incorporation of succinate into glutamate (= alpha-ketoglutarate), aspartate (= oxaloacetate) and alanine (= pyruvate) was studied. The organism was grown on H2 plus CO2 at pH 6.5 in the presence of 1 mM [U-14C-]succinate. Significant amounts of the dicarboxylic acid were incorporated into cellular material under these conditions. Alanine, aspartate, and glutamate were isolated and their specific radioactivities were determined. Only glutamate was found to be labelled. Degradation of glutamate revealed that C-1 of glutamate was derived from CO2 and C-2--C-5 from succinate indicating that in M. thermoautotrophicum alpha-ketoglutarate is synthesized via reductive carboxylation of succinyl CoA. The finding that succinate was not incorporated into alanine and aspartate excludes that oxaloacetate and pyruvate are synthesized from alpha-ketoglutarate via isocitrate or citrate. This is taken as evidence that a complete reductive carboxylic acid cycle is not involved here in autotrophic CO2 fixation.

Alanine↗
PubMed1978

[The aid of bone scans in diagnosis of fibrous dysplasia (author's transl)].

Fibrous dysplasia of the bone does not only occur in childhood as commonly believed, but may also be diagnosed during adult life as a stepwise progressing disease. Bone scans are useful to differentiate active from non-active disease. Suspicious accumulations of the radio-pharmaceutical which may be detected by total body scanning, should be confirmed by roentgen examination as a more specific method. Bone scan is helpful in early detection of focal disease and may visualize lesions in wide-spread disease for further radiological workup.

Age Factors↗
PubMed1978

[Isolated dislocation fracture of the trapezium (author's transl)].

As a very rare injury, isolated fracture, dislocation or rarely dislocation fracture of the trapezium can be connected with difficult diagnostical problems. Routine X-rays of the hand are not always sufficient, because of overlying trapezoid-contours. Special X-rays are additionally necessary. Concerning the therapy, there is a balance in conservative and surgical treatment, depending on the kind and nature of fracture and dislocation.

Adult↗
PubMed1977

Fibrinogen Marburg a new genetic variant of fibrinogen.

A new case of congenital dysfibrinogenemia has been discovered in a 20 year old woman, who suffered from a severe postpartal hemorrhage after the delivery of her first child, followed by episodes of thrombosis. Coagulation studies reveal a prolongation of thrombin time, reptilase time was immeasurable. Thromboplastin time and partial thromboplastin time were slightly prolonged. Low fibrinogen levels were obtained by techniques, which depend on the coagulation velocity following addition of thrombin, while immunological procedures gave slightly diminished values of fibrinogen. Patients's fibrinogen had a moderate inhibitory effect on the fibrin formation in normal plasma. However, inhibitors of the fibrinogen-fibrin conversion could not be detected. Coagulation factors were normal, fibriolysis as well. The cause of the coagulation disorder was found to be a defect of the fibrinogen molecule, leading to an abnormal fibrin polmerization of patient's fibrin monomers. The release of the fibrinopeptides in the paperelectrophoresis was normal. The defect of the fibrinogen molecule did not protect from thrombotic complications. The same defect could be found in the lower scale in patient's father, 4 of her 7 brothers and sisters, and her son.

Adult↗
PubMed1977

Carbon monoxide oxidation by methanogenic bacteria.

Different species of methanogenic bacteria growing on CO(2) and H(2) were shown to remove CO added to the gas phase. Rates up to 0.2 mumol of CO depleted/min per 10 ml of culture containing approximately 7 mg of cells (wet weight) were observed. Methanobacterium thermoautotrophicum was selected for further study based on its ability to grow rapidly on a completely mineral medium. This species used CO as the sole energy source by disproportionating CO to CO(2) and CH(4) according to the following equation: 4CO + 2H(2)O --> 1CH(4) + 3CO(2). However, growth was slight, and the growth rate on CO was only 1% of that observed on H(2)/CO(2). Growth only occurred with CO concentrations in the gas phase of lower than 50%. Growth on CO agrees with the finding that cell-free extracts of M. thermoautotrophicum contained both an active factor 420 (F(420))-dependent hydrogenase (7.7 mumol/min per mg of protein at 35 degrees C) and a CO-dehydrogenating enzyme (0.2 mumol/min per mg of protein at 35 degrees C) that catalyzed the reduction of F(420) with CO. The properties of the CO-dehydrogenating enzyme are described. In addition to F(420), viologen dyes were effective electron acceptors for the enzyme. The apparent K(m) for CO was higher than 1 mM. The reaction rate increased with increasing pH and displayed an inflection point at pH 6.7. The temperature dependence of the reaction rate followed the Arrhenius equation with an activation energy (DeltaHdouble dagger) of 14.1 kcal/mol (59.0 kJ/mol). The CO dehydrogenase activity was reversibly inactivated by low concentrations of cyanide (2 muM) and was very sensitive to inactivation by oxygen. Carbon monoxide dehydrogenase of M. thermoautotrophicum exhibited several characteristic properties found for the enzyme of Clostridium pasteurianum but differed mainly in that the clostridial enzyme did not utilize F(420) as the electron acceptor.

Bacteria↗
PubMed1977

Oxidoreductases involved in cell carbon synthesis of Methanobacterium thermoautotrophicum.

Cell-free extracts of Methanobacterium thermoautotrophicum were found to contain high activities of the following oxidoreductases (at 60 degrees C): pyruvate dehydrogenase (coenzyme A acetylating), 275 nmol/min per mg of protein; alpha-ketoglutarate dehydrogenase (coenzyme A acylating), 100 nmol/min per mg; fumarate reductase, 360 nmol/min per mg; malate dehydrogenase, 240 nmol/min per mg; and glyceraldehyde-3-phosphate dehydrogenase, 100 nmol/min per mg. The kinetic properties (apparent V(max) and K(M) values), pH optimum, temperature dependence of the rate, and specificity for electron acceptors/donors of the different oxidoreductases were examined. Pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase were shown to be two separate enzymes specific for factor 420 rather than for nicotinamide adenine dinucleotide (NAD), NADP, or ferredoxin as the electron acceptor. Both activities catalyzed the reduction of methyl viologen with the respective alpha-ketoacid and a coenzyme A-dependent exchange between the carboxyl group of the alpha-ketoacid and CO(2). The data indicate that the two enzymes are similar to pyruvate synthase and alpha-ketoglutarate synthase, respectively. Fumarate reductase was found in the soluble cell fraction. This enzyme activity coupled with reduced benzyl viologen as the electron donor, but reduced factor 420, NADH, or NADPH was not effective. The cells did not contain menaquinone, thus excluding this compound as the physiological electron donor for fumarate reduction. NAD was the preferred coenzyme for malate dehydrogenase, whereas NADP was preferred for glyceraldehyde-3-phosphate dehydrogenase. The organism also possessed a factor 420-dependent hydrogenase and a factor 420-linked NADP reductase. The involvement of the described oxidoreductases in cell carbon synthesis is discussed.

Anaerobiosis↗
PubMed1977

Demonstration of granulocytic proteases in plasma of patients with acute leukemia and septicemia with coagulation defects.

To show whether direct proteolysis of coagulation factors may play a role in patients with so-called consumption coagulopathy, granulocytic neutral proteases in the plasma of patients with acute myelocytic leukemia and septicemia were assayed by one- and two-dimensional Laurell electrophoresis. Complexes between serum alpha1-antitrypsin and elastase-like granulocytic protease could be demonstrated in those patients with acute myelocytic leukemia and septicemia who also had moderate or severe coagulation defects. Despite the presence of a high antiprotease potential, addition of the elastase-like enzyme to normal plasma resulted in coagulation defects in vitro comparable to those seen in the patients. These results and the ability of the elastase-like protease to destroy isolated clotting factors suggested that in certain types of coagulation factor deficiencies direct proteolysis rather than consumption of clotting factors due to disseminated intravascular coagulation may be operational.

Blood Coagulation Disorders↗
PubMed1976

[Salivary electrolytes and serum digoxin in the Assessment of digitalis intoxication (author's transl)].

Salivary electrolytes (potassium and calcium), as well as serum digoxin levels were measured in 114 patients receiving digoxin or one of its derivatives. The mean value of the product of salivary potassium (mVal/I) and calcium (mVal/i in digoxin-treated patients without signs of digitalis intoxication (group 1) was 235 +/- 137 (SD) and with digitalis intoxication (group 2) 404 +/- 161 (SD). The difference in these values was not of statistical significance. The mean serum digoxin levels were 1.38 +/- 0.6 ng/ml (SD) in group 1 and 2.97 +/- 0.7 ng/ml (SD) in group 2; this difference is highly significant (p less than 0.001). Both salivary electrolytes and serum digoxin levels were falsely elevated in 11% of group 1 patients. 50% of the cases in group 2 showed salivary electrolyte values within the range of group 1, but there was only 1 patient with a serum digoxin level of below 2 ng/ml. It can, thus, be concluded that measurement of the salivary electrolytes is a test of only limited value in the assessment of digitalis intoxication, whereas determination of the serum digoxin level is a valuable diagnostic tool.

Calcium↗
PubMed1976

[Post-heparin-lipolytic activity in acute ethanol-induced hyperlipoproteinemia (author's transl)].

Post-heparin lipolytic-activity (PHLA) was studied in 10 healthy volunteers ingesting 0.5 g of ethanol/kg body weight initially and 0.1 g/kg body weight and hour over 5 hours. This dose led to enhancement in plasma triglycerides to about 170% of the pre-ethanol values. PHLA was determined before, 15 min, 1 and 5 hours after intake of the initial dose and showed no significant changes. These findings are compared with the results of earlier investigations. It is concluded that acute ethanol induced hyperlipoproteinemia in healthy man seems to be due mainly to enhanced hepatic synthesis of triglycerides and release of very low density lipoproteins and not to decrease catabolism of triglyceride rich lipoproteins.

Adult↗
PubMed1976

[Longtime therapy of congenital factor XIII deficiency using factor XIII concentrate].

Factor XIII was determined by enzymatic and immunochemical methods in 3 patients with congenital factor XIII deficiency. Factor XIII activity measured by trans-glutaminase assay was below 1% of normal value in each of these cases. Immunelectrophoresis determination revealed the absence of the functionally active subunit A, whereas subunit S was only slightly diminished (30 to 50% of the normal value). Substitution with factor XIII concentrate caused a parallel increase of factor XIII activity and subunit A concentration. No uptake of factor XIII activity or of subunit. A by platelets could be demonstrated. Despite discontinuous substitution over a period of six years no antibody against factor XIII activity could be demonstrated in one patient with congenital factor XIII deficiency.

Antibodies↗