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Biomedical subjects

E Keller

Publications and source records attributed to E Keller.

At least 307 records · Page 17Linked to original sources
PubMed1984

Intraperitoneal and intravenous cefoperazone kinetics during continuous ambulatory peritoneal dialysis.

Serum cefoperazone (CFP) kinetics after a 1-gm dose added to the peritoneal dialysate were followed in seven patients undergoing continuous ambulatory peritoneal dialysis (CAPD). In a randomized order five of the seven patients received 1 gm IV CFP. Serum samples were collected over 10 hr during one dialysate exchange interval. CFP concentrations were determined by HPLC. After intravenous dosing CFP mean peak and 6-hr serum concentrations were 104.2 +/- 29.1 micrograms X ml-1 and 8.5 +/- 3.8 micrograms X ml-1, mean body clearance was 80 +/- 20 ml X min-1, and mean apparent volume of distribution was 14.6 +/- 3.2 l. The elimination rate constant (kel) varied from 0.29 to 0.38 hr-1 and was almost identical to kel derived from intraperitoneal application (range 0.29 to 0.42 hr-1). Instillation of CFP with the peritoneal dialysate resulted in a rapid rise of serum levels (Tmax = 1.9 +/- 0.7 hr; absorption rate constant ka = 0.68 +/- 0.11 hr-1), and sufficient CFP concentrations (Cmax = 33.2 +/- 5.3 micrograms X ml-1), were maintained over 6 hr (C6 hr = 17.3 +/- 5.8 micrograms X ml-1). Mean systemic availability of intraperitoneal CFP was 95% +/- 12%. Intraperitoneal administration of CFP in patients undergoing CAPD resulted in serum levels of CFP adequate for systemic treatment of bacterial infections.

Adult↗
PubMed1984

[Psychosocial situation of married couples prior to artificial insemination with donor sperm].

57 couples who attended our outpatient department for artificial insemination with donor sperm (AID) had a detailed semistandardized interview prior to treatment. The Giessen Test was used as personality test, as well as a questionnaire concerning the sexual and partner relationship. We found that it was the woman who had to bear the major part of the intrapsychic burden and who primarily suffered because of the problem which was actually caused by male sterility. However, 54 of 57 couples had no psychological difficulties to overcome the sterility problem. These couples developed individual and partnership strategies to deal with the burden of unwanted childlessness. They preferred AID rather than adoption, because for the woman this alternative offers the chance of real parenthood. AID seems to provide a medico-technical solution for couples with sterility problems: the reproductive process at the biological level was regarded as distinctly separated from their future role as parents which they considered to be a social task.

Adult↗
PubMed1984

[Significance of the esophagogram compared to computed tomography in esophageal cancer].

A comparison of the oesophagogram and computed tomography has shown that there is angulation of the axis of the oesophagus in 75% of patients with perioesophageal tumour spread. This angulation is more common due to tumour in the younger patient. Longer tumours tend to show deeper infiltration into the peri-oesophageal tissue, although its frequency is not necessarily increased. Tumours longer than 8 cm. show infiltration in about 80% of cases.

Esophageal Neoplasms↗
PubMed1984

[Therapy of chronic antero-lateral instability of the upper ankle and its results].

From 1970 to 1980, 157 modified Watson-Jones grafts were performed at the BG Unfallklinik Tübingen. The advantages and disadvantages of this procedure are discussed and compared with other surgical procedures. Follow-up examinations were possible in 119 patients. In all patients a significant improvement of the stability could be attained. The functional reduction of mobility appeared minimal. 46 of 64 athletes resumed full sports activities. 90% of the patients stated to be satisfied with the results.

Adolescent↗
PubMed1984

Increased nonrenal clearance of cimetidine during antituberculous therapy.

To investigate the influence of antituberculous treatment on Cimetidin (Ci) disposition, 300 mg Ci were administered intravenously to 12 patients on triple drug therapy (Ethambutol 25 mg/kg/d, Isoniazid 8 mg/kg/d, Rifampicin (Rif) 8 mg/kg/d) and to 13 healthy subjects. Plasma levels and urinary recovery of Ci and its major metabolite Ci-Sulfoxide (CiS) were measured by HPLC. In patients on tuberculostatics nonrenal clearance (Clnr) increased by 52% (395 +/- 85 ml/min, controls 261 +/- 74 ml/min), while total clearance (ClB) (703 +/- 154 ml/min controls 632 +/- 118 ml/min) and volume of distribution (Vd beta) (1.35 +/- 0.33 l/kg, controls 1.6 +/- 0.37 l/kg) remained unchanged. The reduced renal clearance of Ci in the patients (308 +/- 125 ml/min, controls 371 +/- 115 ml/min) appeared to be mainly dependent on reduced renal function and not on antituberculous therapy. The CiS/Ci ratio in urine was unchanged in the patients (16 +/- 6.5, controls 20.5 +/- 10.6). The increased elimination of undegraded Ci via nonrenal pathways under tuberculostatic triple drug therapy may be a consequence of Rifampicin induced microsomal enzyme induction.

Adult↗
PubMed1983

[Biosynthesis of phenylalanine and tyrosine: arogenic acid, a new intermediate product].

With the discovery of arogenic acid two new pathways for the biosynthesis of phenylalanine and tyrosine have been revealed. The occurrence of two, three, or four pathways for the biosynthesis of phenylalanine and tyrosine in microorganisms and plants may be a useful tool for taxonomic classifications. Investigations on enterobacteriaceae, pseudomonads, flavobacteria, streptomycetes, archaebacteria, and on Sphaerotilus, Trichococcus and Leptothrix species from bulking sludge are described. The possible role of arogenate in the evolution of the pathways for tyrosine and phenylalanine biosynthesis is discussed.

Amino Acids, Dicarboxylic↗
PubMed1983

[Relaparotomy, retrospective analysis and intensive care aspects].

A high mortality rate of the patients in the Surgical University Clinic Mainz in 2441 laparotomies from 1977 to 1979 with 92 relaparotomies in 66 patients (40% proving fatal) could be associated with the following factors: female sex, old age in males, malignant disease, esp. carcinoma of pancreas, colon and rectum, upper gastrointestinal bleeding, presence of concomitant affections, esp. three or more and particularly angiocardiopathy, liver diseases and after radiotherapy, long lasting primary operation, several operations in short intervals (about a week). Astonishingly we found a lower rate of mortality in cases of: Primary laparotomy in an emergency situation, postoperative complications within the first two days or after several weeks, multiple relaparotomies within intervals of at least two weeks. In cases of several severe postoperative complications, esp. renal insufficiency with dependence on dialysis and simultaneous respiratory insufficiency with dependence on artificial respiration a relaparotomy is indicated, if the intra-abdominal complication can be cured. In these cases the intensive care cannot cure the patient's conditions, but mechanical respiration and dialysis improve it. The existence of lethal trias of renal and respiratory insufficiency with a surely unremovable surgical problem forbids a relaparotomy.

Adolescent↗
PubMed1983

Brain glutamate inhibition and amnesia: evidence provided by proline analog action.

The action of proline and its analog as glutamate antagonists was investigated in CNS tissue of the neonatal chick. Avian brain slices were incubated in low concentrations of L-proline, D-proline, DL-3,4-dehydro-proline, L-prolyl-L-proline, or in avian physiological salt solution before depolarization was induced by application of 45 mM K+. Glutamate was determined in the efflux material collected both before and after tissue stimulation. The release of endogenous glutamate was inhibited significantly by exposure to L-proline, DL-3,4-dehydroproline and L-prolyl-L-proline. The degree of glutamate inhibition correlated with the amnestic potency of these substances. The manner in which these results strengthen the hypothesis of glutamate involvement in memory processes is discussed.

Amnesia↗
PubMed1983

Similarities in the control of the speech articulators and the limbs: kinematics of tongue dorsum movement in speech.

The kinematics of tongue dorsum movements in speech were studied with pulsed ultrasound to assess similarities in the voluntary control of the speech articulators and the limbs. The stimuli were consonant--vowel syllables in which speech rate and stress were varied. The kinematic patterns for tongue dorsum movements were comparable to those observed in the rapid movement of the arms and hands. The maximum velocity of tongue dorsum raising and lowering was correlated with the extent of the gesture. The slope of the relationship differed for stressed and unstressed vowels but was unaffected by differences in speech rate. At each stress level the correlation between displacement and peak velocity was accompanied by a relatively constant interval from the initiation of the movement to the point of maximum velocity. The data are discussed with reference to systems that can be described with second-order differential equations. The increase in the slope of the displacement/peak-velocity relationship for unstressed versus stressed vowels is suggestive of a tonic increase in articulator stiffness. Variations in displacement are attributed to the level of phasic activity in the muscles producing the gesture.

Arm↗
PubMed1983

Single-dose ceftriaxone kinetics in functionally anephric patients.

The disposition profile of ceftriaxone was studied in 12 functionally anephric patients (creatinine clearance less than 10 ml/min) who received bolus injections of 150, 500, and 1500 mg IV in a noncrossover fashion. As in healthy subjects, the kinetics in uremic patients were nonlinear for total (bound plus unbound) and linear for free (unbound) drug. The plasma protein binding was reduced due to a decreased association constant, resulting in a doubling of the free fraction in plasma. Ten of 12 patients showed nonrenal clearance values of unbound drug (ClFNR) identical to those in healthy adults and only minor increases in their biologic t1/2(beta) compared to normal (12 and 8 hr). These patients would require no dose adjustments in their dosing regimen. Two of the patients exhibited decreased ClFNR values and increased t1/2(alpha) of 20 and 34 hr. Anephric patients with impaired nonrenal elimination would require minor dose adjustments.

Adult↗
PubMed1983

Clonidine (Haemiton) as a reliable stimulus of growth hormone secretion in patients with short stature.

In 14 patients with short stature aged 4-14 years the effect of clonidine has been investigated. A single oral dose of 0.15 mg/m2 surface area is followed by a marked increase of hGH concentration in blood with a peak value between 60 and 90 min after the administration of the drug. The hGH increase caused by clonidine was comparable to the rise during insulin-induced hypoglycemia. In 5 patients both stimuli failed to increase hGH release. The test procedure is simple. It shows only minimum side effects and can therefore be especially recommended in outpatients.

Adolescent↗
PubMed1983

Computerized measurement of tongue dorsum movements with pulsed-echo ultrasound.

A computerized system for the measurement of tongue dorsum movements with pulsed echo ultrasound is described. The presentation focuses on technical and methodological considerations in the on-line acquisition of vertical tongue movement information, its digital processing and display. Problems associated with transducer placement, peak detection, data averaging, and curve fitting are considered, and validation procedures based on x ray and indicators of measurement reliability are reported. The discussion centers on advantages and disadvantages of the technique and its applications.

Computers↗
PubMed1983

Regional effects of ethanol on glutamate levels, uptake and release in slice and synaptosome preparations from rat brain.

Chronic ethanol treatment effects a decrease in K+-stimulated endogenous glutamate release and an increase in glutamate levels in rat frontal cortex. This treatment also increases (3H)-glutamate uptake in striatal and hippocampal slices. No uptake changes were observed in either cortical slices or synaptosomes. Ethanol withdrawal increases K+-stimulated glutamate release in cortex and hippocampus and glutamate levels in cortex, striatum and hippocampus. (3H)-glutamate uptake is increased in striatum of withdrawn animals. Thus, regional variations were observed with regard to both effect and degree of effect. Because in vitro and acute ethanol treatments had no effect on uptake or release, these changes probably result from activated feedback mechanisms that attempt to compensate for ethanol's action on brain systems rather than direct effects on membrane structure. Combined level-release data suggest an effect of ethanol on glutamate distribution in cortex and striatum. Combined uptake and release data indicate a correlation between diminished glutamate synaptic activity and the addicted state, and between heightened glutamate synaptic activity and the withdrawn state.

Alcohol Drinking↗
PubMed1983

[Biosynthesis of phenylalanine and tyrosine in Flavobacteria].

The enzymes of the terminal steps of phenylalanine and tyrosine biosynthesis, chorismate mutase, prephenate dehydratase, arogenate dehydratase, prephenate dehydrogenase and arogenate dehydrogenase, were studied in 11 different species of the genus Flavobacteria. A comparison of the specific activities, cofactor specificity and regulation of the enzymes, allows a differentiation within the Flavobacteria. All strains studied utilize both arogenate and p-hydroxyphenylpyruvate as an intermediate in L-tyrosine synthesis. Phenylpyruvate was found to be the precursor of phenylalanine in most bacteria. No feedback inhibition of arogenate dehydrogenase by phenylalanine and tyrosine was observed. The diverse strains of the flavobacteria were found to possess different regulatory patterns with respect to the action of phenylalanine and tyrosine on the other enzymes. On the basis of these results a tentative classification of the Flavobacteria within the two groups formed by the different DNA base ratios is proposed.

Chemical Phenomena↗