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Biomedical subjects

G Fuchs

Publications and source records attributed to G Fuchs.

At least 73 records · Page 4Linked to original sources

Effects of nicotine and its major metabolites on blood pressure in anaesthetized rats.

Blood pressure and heart rate in anaesthetized rats has been determined after i.v. injection of increasing doses of nicotine (NI) and its major metabolites, i.e. continine (CO), nornicotine (NOR), metanicotine (MN) and dihydrometanicotine (DMN). NI and MN elicited similar dose response curves, increasing blood pressure according to the dose injected. However, the dose response curve of MN was shifted to the right. Furthermore DMN caused similar pressor effects than MN and the pressor effects of NOR was even weaker. Only after injection of CO was a dose-dependent depressor effect observed and this was reversed after very high doses. CO also reduced heart rate in a dose-dependent manner, whereas NI and its other metabolites did not significantly change heart rate.

Animals

Formation of carbon monoxide from CO2 and H2 by Methanobacterium thermoautotrophicum.

Cell suspensions of Methanobacterium thermoautotrophicum were found to reduce CO2 with H2 to CO at a maximal rate of 100 nmol X min-1 X mg protein-1. Half-maximal rates were obtained at a H2 and a CO2 concentration in the gas phase of 10% and 30%, respectively. The CO concentration in the gas phase surpassed the equilibrium concentration by a factor of more than 15 which indicates that CO2 reduction with H2 to CO was energy-driven. This was substantiated by the observation that the cells only formed CO when they also generated methane and that CO formation was completely inhibited by uncouplers. CO formation by cell suspensions and by growing cells was inhibited by cyanide. Neither methane formation nor the electrochemical proton potential were affected by this inhibitor. Cyanide was shown to inactivate specifically the carbon monoxide dehydrogenase present in M. thermoautotrophicum. It is therefore concluded that reduction of CO2 to CO is catalyzed by this enzyme. CO production by growing cells was 5-10-times slower than by resting cells. This is explained by effective CO assimilation in growing cells; when CO assimilation was inhibited by propyl iodide the rate of CO production immediately increased more than tenfold.

Aldehyde Oxidoreductases

Extracorporeal shock-wave lithotripsy: one-year experience with the Dornier lithotripter.

Extracorporeal shock-wave lithotripsy (ESWL) has now been in clinical use for more than 4 years. In October 1983, the second kidney lithotripter in the world was installed in our department and, from then until October 1984, 800 treatments were performed on 733 patients. Our results confirm the promising reports published by the Munich group. Furthermore, it was possible to extend the range of indications by combining ESWL with percutaneous procedures, such as percutaneous nephrolithotomy and ureteroscopy. As a result only 7% of all patients who were referred to our hospital with urinary stones (4% of renal stone patients and 15% of those with ureteral stones) had to undergo open surgery.

Combined Modality Therapy

Antegrade ureteroscopy for stone removal.

Antegrade ureteroscopy, using the 11-French ureteroscope via a percutaneous transrenal access, provides safe and easy endoscopic exploration of the ureter above the level of the iliac vessels. The technique has proven to be reliable and effective for the removal of obstructing proximal ureteral calculi: all of the 22 patients who underwent antegrade ureteroscopy were stone-free after treatment. Since the introduction of this new technique in our department, no more open surgery has been required to manage ureteral calculi.

Endoscopy

The clinical significance of alpha 1-antitrypsin-elastase (alpha 1AT-ELP) and alpha 2-antiplasmin-plasmin (alpha 2AP-PL) complexes for the differentiation of coagulation protein turnover: indications for plasma protein substitution in patients with septicaemia.

In inflammation, particularly in septicaemia, complex coagulation disorders may lead to a dangerous haemorrhagic diathesis. The conventional concept for this syndrome called DIC implicates the occurrence of active thrombin in the circulation, which may be followed by hyperfibrinolysis due to plasmin formation. In this study data are presented suggesting an important role for a third proteolytic system, granulocytic elastase. The complexes of plasmin and elastase with their specific inhibitors, alpha 2-antiplasmin-plasmin (alpha 2AP-PI) and alpha 1-antitrypsin-elastase (alpha 1AT-ELP) were determined immunologically. The alpha 1AT-ELP appears mainly in gram-negative septicaemia, particularly in meningococcal disease. The estimation of alpha 2AP-PI and alpha 1AT-ELP, together with a method for the detection of the antithrombin III--thrombin complex which remains to be established, is a suitable tool for for the differential diagnosis of the consumption of coagulation proteins. The assumption that at least three proteolytic systems participate in the development of the haemorrhagic diathesis during inflammation leads to the concept of a broad, comprehensive substitution therapy with e.g. concentrates of AT III, PPSB, or fresh frozen plasma. The aim of this treatment is to replace not only the consumed procoagulatory factors, but also the lacking inhibitors in order to control this "abnormal proteolysis syndrome".

Adult

[Experience with extracorporeal shockwave lithotripsy based on 5 years' clinical use].

After 6 years of experimental research at the Departments of Urology and Surgical Research of the Ludwig-Maximilian University in Munich, extracorporeal shock-wave lithotripsy (ESWL) was introduced into clinical use in 1980. Uniquely successful and increasingly requested by stone patients, the method soon became widespread. Currently more than 70 lithotriptors are in operation worldwide and over 30,000 treatments have been carried out successfully. Clinical experience in all centers has proved the safety, reliability and reproducibility of the method. Currently, approximately 70% of nonselected stone patients are eligible to receive ESWL treatment and, when combined with endourological procedures, more than 95% of patients can benefit from this method and thus avoid open surgery.

Adolescent

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

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

[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