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Biomedical subjects

G Fuchs

Publications and source records attributed to G Fuchs.

At least 91 records · Page 5Linked to original sources
PubMed1995

2-Aminobenzoyl-CoA monooxygenase/reductase. Evidence for two distinct loci catalyzing substrate monooxygenation and hydrogenation.

2-Aminobenzoyl-CoA monooxygenase/reductase catalyzes both monooxygenation and hydrogenation of anthraniloyl-CoA. Its reactivity with 11 substrate analogs has been investigated. Only 2-aminobenzoyl-CoA (anthraniloyl-CoA) in its normal and deuterated (5-2H) form is a full substrate, and only traces of 2-hydroxybenzoyl-CoA (salicyloyl-CoA) are probably monooxygenated but not hydrogenated. The purified enzyme is a homodimer and has been resolved preparatively into three major species by anion-exchange chromatography on Mono Q. All three species have the same specific activity when reconstituted to full content of FAD, they differ, however, substantially in their mode of binding FAD. The oxidized or fully reduced enzyme forms bind tightly 0.5 mol/mol of the substrate 2-aminobenzoyl-CoA (Kd = 1-2 microM). The enzyme can be depleted of approximately 50% of its FAD, which corresponds to essentially complete removal from one of the two binding sites, reflecting a large difference in the affinity for FAD. From this it is deduced that the two sites are not equivalent. Removal of FAD from one binding site leads to loss of the hydrogenation capacity of the enzyme, while monooxygenation catalysis is retained. The FAD cofactors of the two binding sites differ drastically in their reactivities towards NADH, oxygen and N-ethylmaleimide. Exchange of reducing equivalents between the two FAD cofactors at the respective binding sites is very slow and irrelevant compared to the rates of catalysis. It is concluded that the enzyme, which has been proposed to consist of two identical polypeptide chains [Altenschmidt, U., Bokranz, M. & Fuchs, G. (1992) Eur. J. Biochem. 207, 715-722], contains two active centers which differ substantially in their catalytic activity. One center belongs to the class of monooxygenases, the other one to the (de)hydrogenases. This must result from substantially different interaction of the same flavin cofactors with protein functional groups and is, to our knowledge, unprecedented in flavoprotein enzymology.

Catalysis↗
PubMed1995

Benzoyl-coenzyme-A 3-monooxygenase, a flavin-dependent hydroxylase. Purification, some properties and its role in aerobic benzoate oxidation via gentisate in a denitrifying bacterium.

A new variant of aerobic benzoate degradation has been found in a denitrifying bacterium in which benzoyl-CoA is the first intermediate [Altenschmidt, U., Oswald, B., Steiner, E., Herrmann, H. & Fuchs, G. (1993) New aerobic benzoate oxidation pathway via benzoyl-coenzyme A and 3-hydroxybenzoyl-coenzyme A in a denitrifying Pseudomonas sp, J. Bacteriol. 175, 4851-4858)]. The initial reaction is catalyzed by benzoate-CoA ligase (AMP-forming), converting benzoate into benzoyl-CoA. The next step is 3-hydroxylation of benzoyl-CoA to 3-hydroxybenzoyl-CoA catalyzed by a flavin-nucleotide-dependent monooxygenase, benzoyl-CoA 3-monooxygenase. This novel enzyme has been purified and studied. It is specific for NADPH and requires the presence of a flavin nucleotide for activity; both FAD or FMN function similarly well as cofactor. Only benzoyl-CoA, but not benzoate, is hydroxylated. The protein is a monomer of M(r) 65,000 and is induced when cells are grown aerobically with benzoate. 3-Hydroxybenzoyl-CoA is further hydroxylated para to the hydroxyl group affording 2,5-dihydroxybenzoate (gentisate). This reaction requires another monooxygenase, 3-hydroxybenzoyl-CoA 6-monooxygenase, which is unspecific specific with respect to the pyridine nucleotide. Cells contain a second 6-monooxygenase activity which acts on free 3-hydroxybenzoate. Based on these and other data, the outlines of the new aerobic benzoate pathway have been deduced. The proposed intermediates are benzoyl-CoA, 3-hydroxybenzoyl-CoA, gentisate, maleylpyruvate, fumarylpyruvate and fumarate plus pyruvate.

Benzoates↗
PubMed1995

Purification and properties of benzyl alcohol dehydrogenase from a denitrifying Thauera sp.

Toluene and related aromatic compounds are anaerobically degraded by the denitrifying bacterium Thauera sp. strain K172 via oxidation to benzoyl-CoA. The postulated initial step is methylhydroxylation of toluene to benzyl alcohol, which is either a free or enzyme-bound intermediate. Cells grown with toluene or benzyl alcohol contained benzyl alcohol dehydrogenase, which is possibly the second enzyme in the proposed pathway. The enzyme was purified from benzyl-alcohol-grown cells and characterized. It has many properties in common with benzyl alcohol dehydrogenase from Acinetobacter and Pseudomonas species. The enzyme was active as a homotetramer of 160 kDa, with subunits of 40 kDa. It was NAD(+)-specific, had an alkaline pH optimum, and was inhibited by thiol-blocking agents. No evidence for a bound cofactor was obtained. Various benzyl alcohol analogues served as substrates, whereas non-aromatic alcohols were not oxidized. The N-terminal amino acid sequence indicates that the enzyme belongs to the class of long-chain Zn(2+)-dependent alcohol dehydrogenases, although it appears not to contain a metal ion that can be removed by complexing agents.

Alcohol Oxidoreductases↗
PubMed1995

[Education of the medical student in first aid, emergency and disaster medicine--the Graz model].

In Austria emergency and disaster medicine is a young interdisciplinary subject. It is only a borderline discipline encompassing different medical subjects and was subdivided into emergency medicine for medical doctors only and first-aid for lay people and emergency technicians. In fact, since emergency medicine without first-aid can't be successful, the Department of Anaesthesiology at the University of Graz let all students of the medical faculty have a comprehensive education in the treatment of injured of acutely ill patients. According to the three steps of the study lectures and practices, all parts of first-aid, emergency and disaster medicine were offered. In spite of the short time since this has been running, we found a good acceptance and we hope to increase the interest evinced by medical students in our training programme.

Austria↗
PubMed1995

Complications of laparoscopic nephrectomy in 185 patients: a multi-institutional review.

PURPOSE: We document the incidence of complications associated with laparoscopic nephrectomy in a multi-institutional study. MATERIALS AND METHODS: The study included the initial 185 patients undergoing laparoscopic nephrectomy at 5 centers in the United States between June 1990 and July 1993. RESULTS: A total of 30 patients (16%) had 34 complications. There was no mortality. Access-related complications included 2 cases of hernia formation at the trocar site, 1 abdominal wall hematoma and 1 trocar injury to a hydronephrotic kidney. Intraoperative complications included 5 cases of vascular injury, 1 splenic laceration and 1 pneumothorax. Postoperative complications involved the gastrointestinal tract in 6 cases, cardiovascular system in 6, genitourinary tract in 4, respiratory system in 4 and musculoskeletal system in 2. Miscellaneous complications occurred in 3 patients. Open surgical intervention was required electively in 8 patients and on an emergency basis in 2. The incidence of complications decreased with experience: 71% occurred during the initial 20 cases at each institution. CONCLUSIONS: In our early experience the complication rate for laparoscopic nephrectomy was 12% in patients with benign renal disease and 34% in those with renal cancer. Based on this collective experience, recommendations for prevention, recognition and treatment of complications are made.

Adult↗
PubMed1995

Taxonomic position of aromatic-degrading denitrifying pseudomonad strains K 172 and KB 740 and their description as new members of the genera Thauera, as Thauera aromatica sp. nov., and Azoarcus, as Azoarcus evansii sp. nov., respectively, members of the beta subclass of the Proteobacteria.

In the past workers have isolated several pseudomonad strains which have been used for studies of anaerobic aromatic metabolism. The best studied of these strains are strains KB 740T (T = type strain) and K 172T. The taxonomic positions of these two organisms were determined by classical methods, including experiments to determine substrate spectrum, quinone type, and total fatty acid composition. Our results clearly excluded these strains from the authentic genus Pseudomonas, which belongs to the gamma subclass of the Proteobacteria. Instead, the properties of these organisms indicated that they belong to the beta subclass of the Proteobacteria. The sequences of the 16S ribosomal DNA genes confirmed this conclusion and indicated that strain K 172T represents a new species of the genus Thauera, Thauera aromatica, and that strain KB 740T represents a new species of the genus Azoarcus, Azoarcus evansii.

Base Sequence↗
PubMed1995

[Follow-up of Werlhof disease after onset of treatment with maprotiline].

Whereas leucocytopenia is reported to be a relatively frequent side-effect of treatment with tricyclic and tetracyclic antidepressants and atypical neuroleptic agents, isolated thrombocytopenias are rare. To our knowledge there are no reports of thrombocytopenia in connection with the tetracyclic antidepressant maprotiline. This report describes the case of a 53-year-old female patient with neurotic depression and an initially unsuspected chronic idiopathic thrombocytopenic purpura (ITP). Following previous treatment with an angiotensin-converting enzyme inhibitor, cilazapril, and an estrogen derivative, the patient developed an episode of the ITP after beginning treatment with maprotiline. The possible aetiology and the course of the illness are discussed.

Amitriptyline↗
PubMed1994

Evidence that phenol phosphorylation to phenylphosphate is the first step in anaerobic phenol metabolism in a denitrifying Pseudomonas sp.

Anaerobic phenol degradation has been shown to proceed via carboxylation of phenol to 4-hydroxybenzoate. However, in vitro the carboxylating enzyme was inactive with phenol; only phenylphosphate (phosphoric acid monophenyl ester) was readily carboxylated. We demonstrate in a denitrifying Pseudomonas strain that phenylphosphate is the first detectable product formed from phenol in whole cells and that subsequent phenylphosphate consumption parallels 4-hydroxybenzoate formation. These kinetics are consistent with phosphorylation being the first step in anaerobic phenol degradation. Various cosubstrates failed so far to act as phosphoryl donor for net phosphorylation of phenol in cell extracts. Yet, cells anaerobically grown with phenol contained an enzyme that catalyzed an isotope exchange between [U-14C]phenol and phenylphosphate. This transphosphorylation activity was anaerobically induced by phenol but was stable under aerobic conditions and required Mn2+ and polyethylene glycol. Activity was optimal at pH 5.5 and half-maximal with 0.6 mM Mn2+, 0.2 mM phenylphosphate, and 1 mM phenol. It is proposed that the phenol exchange/transphosphorylation reaction is catalyzed as partial reaction by an inducible phenol phosphorylating enzyme. The isotope exchange demands that a phosphorylated enzyme was formed in the course of the reaction, which might be similar to the phosphotransferase system of sugar transport.

Anaerobiosis↗
PubMed1994

Laparoscopic vesicoureteroplasty in children: initial case reports.

OBJECTIVE: To determine the feasibility of performing laparoscopic vesicoureteroplasty in children. METHODS: Two pediatric patients, a two-year-old boy and a five-year-old girl, underwent laparoscopic vesicoureteroplasty for vesicoureteral reflux. Operating time was two hours fifteen minutes and three hours fifteen minutes, respectively. RESULTS: The reflux was successfully corrected without morbidity, and they required only short hospitalization (23 hours) and exhibited decreased peri- and post-operative pain as well as improved cosmesis. CONCLUSIONS: These cases represent the first implementation of this technique in humans. We stress that this is a preliminary report and suggest that this technique deserves further study.

Child, Preschool↗
PubMed1994

Laparoscopic renal surgery in children.

A total of 17 laparoscopic renal procedures was performed in children, including nephrectomy (10), nephroureterectomy (4), partial nephrectomy (2) and giant renal cyst excision (1). Patient age ranged from 4 months to 11 years (average age 34 months). The average operating time was 2 hours and 15 minutes, ranging from 1 hour 50 minutes to 2 hours 45 minutes. The usual period of hospitalization was 23 hours, with the longest being 36 hours for 2 patients. No complications ensued. Despite the decreased working space in children, laparoscopic renal surgery offers compelling advantages, including short hospitalization, less perioperative and postoperative pain, improved cosmesis, earlier return to normal unrestricted activities and early return to work for the parents. Methods to accomplish renal laparoscopic surgery safely in children are detailed.

Child↗
PubMed1994

Sitting position for neurosurgery: experience with preoperative contrast echocardiography in 301 patients.

A persisting foramen ovale (PFO) is the most common cause of paradoxical air embolism. To detect right-to-left shunting, transthoracic contrast echocardiography was performed preoperatively in 301 patients scheduled for neurosurgical procedures in the sitting position. Echocardiography yielded evaluable results in 285 patients (94.7%). In 72 of 285 patients (25.2%), a PFO was diagnosed on the basis of contrast echo signals appearing in the left atrium or ventricle within 5 heart cycles after application of contrast medium via a peripheral vein. If echo signals appeared in the left heart after more than 5 heart cycles, an intrapulmonary right-to-left shunt was considered (11 patients, 3.9%). Venous air embolism (VAE) occurred in 27.4% of 226 patients operated on in the sitting position and in none of the 59 patients operated on in a nonsitting position. We conclude that the sitting position during neurosurgery should be avoided in patients with preoperative evidence of a right-to-left shunt at contrast echocardiography to reduce the risk of paradoxical air embolism (PAE).

Adolescent↗
PubMed1994

Cardiac function in malnourished children.

The cardiovascular status of severely malnourished children was characterized before, during, and after nutritional rehabilitation. In most children with third-degree malnutrition, cardiac mass was decreased on admission to the hospital and recovered subsequent to nutritional therapy. All children had echocardiographic and Doppler measurements indicative of impaired ventricular function which significantly improved during the course of hospitalization, as evidenced in part by the change in fractional shortening (P = 0.015), mean velocity of circumferential fiber shortening (P = 0.038), and systolic time interval (P = 0.030). We conclude that children with primary third-degree malnutrition not only have cardiac muscle wasting, but also have inherent ventricular dysfunction as the result of severe malnutrition that responds to nutritional therapy. Particular care with fluid administration is imperative in the first week of therapy, when heart function is the most compromised.

Child, Preschool↗
PubMed1994

Computer-assisted neurovegetative monitoring in patients after heart transplantation.

The effects of orthotopic heart transplantation on spontaneous fluctuations of the respiration rate and heart rate were studied with a computer-assisted system for neurovegetative monitoring in 22 patients (mean age +/- SD: 48.7 +/- 9.4 years) 19.5 +/- 14.4 months after transplantation. The control group consisted of 12 healthy volunteers (mean age +/- SD: 38.7 +/- 6.6 years). The mean (+/- SE) respiratory rate was higher in the transplantation group than in the control group (17.7 +/- 0.8/min vs. 14.6 +/- 1.1 breaths/min, P < 0.2). The mean variability of the respiratory rate was smaller in the transplant patients than in the controls (3.7 +/- 0.3 vs. 2.8 +/- 0.4, P < 0.2). The heart rate variability coefficient in the patients after transplantation was lower than that in the controls (1.3 +/- 0.1% vs. 6.9 +/- 0.5%, P < 0.001). Spectral analysis of heart rate variability showed a smaller decrease of variability of respiration (P < 0.05) than of blood pressure regulation (P < 0.001) or of the angiotensin-renin system (P < 0.001). A separate group of 7 transplant patients (mean age 51.0 +/- 7.7 years) had activated cardiac pacemakers and thus no spontaneous physiologic heart rate oscillations. The variability of the respiratory rate in these patients was lower than in the other 22 transplant patients (1.8 +/- 0.2 vs. 3.7 +/- 0.3, P < 0.001). The data provided by multiparametric neurovegetative monitoring support the evaluation of complex regulatory mechanisms of respiratory and cardiovascular function and their adaptability after orthotopic heart transplantation.

Adult↗
PubMed1994

[15 years of geriatric day care clinics in Germany].

Day hospital treatment for psycho-geriatric patients in the Federal Republic of Germany started in 1976. At present (October 1991) 13 psychogeriatric day hospitals are established. The day hospitals offer a wide range of diagnostic and therapeutic strategies. Though they are expected to be of great importance especially for the elderly, day hospitals don't play a significant part within the care system for psycho-geriatric patients in Germany. It seems to be recommendable, to establish more psycho-geriatric day hospitals, especially together with an out-patient department and an information centre ("Geronto-psychiatrisches Zentrum"). In addition the care system should be supplied with day centres, in particular for those patients suffering from chronic paranoid psychosis or dementia; the medical care of out-patients should be improved. Besides that the efficacy of day hospital treatment for psycho-geriatric patients should be evaluated.

Aged↗
PubMed1994

Tremors in Parkinson's disease: symptom analysis and rating.

The object of the present study was to evaluate the hand tremor occurring under various conditions in 81 patients with Parkinson's disease (PD) and to statistically analyze their relation to clinical rating items. We found that resting and action tremor have to be separated, whereas postural tremor can be related to either one of them. Resting tremor does not correlate with disability items or performance items except for an item rating social handicaps. Action tremor shows some influence on performance items. Current rating scales of PD represent a valid measure of resting tremor but are less valid for the measurement of action tremor.

Adult↗