Search PubMed⌕ Search

Biomedical subjects

H Graf

Publications and source records attributed to H Graf.

At least 217 records · Page 12Linked to original sources
PubMed1979

[Metabolism of colostomized laying hens with 15N-labeled wheat. 2. Incorporation of the labeled nitrogen into fractions of the egg].

The colostomised hens received 15N-labelled wheat. For a period of 8 days the incorporation of the 15N excess (15N') into the albumen, the yolk and the egg-shell was measured. In addition to that, the values for atom-percent of 15N' in the amino acids lysine, histidien and arginine of the albumen and the yolk were ascertained. The egg-shell and the albumen were labelled shortly after the beginning of the experiment. In both fractions the atom-per cent of 15N' rises more quickly than in the yolk. After the withdrawal of the labelled feed the decrease in the yolk was slower than in the egg-shell and the albumen. Concerning the atom-per cent of 15N' there is hardly a difference between the total N and the amino acids. Despite the different supply with amino acids, the relation of histidine 15N' : lysine 15N' : arginine-15N' in the yolk and the albumen remains largely constant. It is 1 : 2 : 3 and corresponds to the quantitative relation of the N content of the three amino acids in the egg protein. The utilisation of 14N and 15N' of the wheat lysin for the egg synthesis amounts to approximately 50%. There are considerable differences between the utilisation of 15N' of the histidine and 15N' of the arginine and the 14N of the two dietary amino acids.

Amino Acids↗
PubMed1979

Oxycytochrome P-450: its breakdown to superoxide for the formation of hydrogen peroxide.

Four different experimental studies are described which were designed to evaluate the role of oxycytochrome P-450 in the formation of superoxide anions and hydrogen peroxide. The use of lipophilic copper chelates with superoxide dismutase like activity revealed that the primary site of interaction of these agents is related to the inhibition of the flavoprotein. NADPH-cytochrome P-450 reductase. Measurements of the proton assisted nucleophilic displacement of superoxide from oxycytochrome P-450 by high concentrations of sodium azide indicated an increase in the rate of hydrogen peroxide formation concomitant with the inhibition of the N-demethylation of ethylmorphine. Studies on the effect of NADH on the rate of hydrogen peroxide formation during NADPH oxidation by liver microsomes failed to reveal a stimulatory or synergistic effect in a manner analogous to results obtained during the cytochrome P-450 dependent oxidation of substrates such as ethylmorphine. These results suggest that hydrogen peroxide formation may not require the reduction of oxycytochrome P-450 to peroxycytochrome P-450. Measurements of the reduction of succinylated cytochrome c using purified cytochrome P-450 and the flavoprotein, NADPH-cytochrome P-450 reductase, directly demonstrate the formation of superoxide anions. It is concluded that oxycytochrome P-450 may decompose to generate hydrogen peroxide.

Animals↗
PubMed1979

[Etiology of dysgnathia].

As to the development of dysgnathias, a multifactorial system must be assumed, the analysis of single components being limited. These conditions are induced by several genes and various exogenous influences. Starting from these statements, the author considers the hereditary and the environmental factors as a dialectical unit, associates the implications of both groups of factors with typical forms of dysgnathias and draws conclusions as to the prognosis of "mainly genetically" and "mainly environmentally" induced dental and occlusal malpositions.

Humans↗
PubMed1979

A method for analysis of human mandibular occlusal movement.

A new method was developed to produce perspectives and maps of the top of Posselt's envelope of motion, the part that is mainly determined by occlusal tooth contact. Mandibular occlusal gliding movements were recorded in human subjects by optoelectronic tracking of infrared light emitters fixed to the subjects upper and lower teeth. Recordings were made by a commercially available electronic camera system that was extended to meet the special needs. An elaborate computer program was developed to process the information and convert it into graphic plots. Care was taken to make the system easy to use.

Computers↗
PubMed1979

[Radiation exposure of teeth and temporomandibular joints by radiography].

According to a report by Poretti (1975) 21,4% of all medical diagnostic radiographs in Switzerland are dental. In order to determine the associated radiation doses to patients, phantom measurements of skin and gonad exposures were made utilizing modern dental x-ray equipment and techniques. Following procedures in accordance with federal safety regulations it was not possible to measure dose values at the gonad level by single dental or temporomandibular radiographs, even by the most sensitive measuring device. 50 cumulative exposures without lead apron resulted in a range of gonad doses from 3.1 to 199 microR for dental and temporomandibular joint x-rays. Results of skin surface doses ranged from 38 to 289 mR for single dental film exposure and from 64 to 494 mR for single TMJ exposures. Consistent use of parallel technique with long cone equipment, small diaphragms, high kilovoltage and use of the lead apron guarantee great safety against radiation hazard in dental radiography.

Dose-Response Relationship, Radiation↗
PubMed1979

Handling of phosphate by the transplanted kidney.

Maximal tubular phosphate reabsorption capacity corrected for changes in glomerular filtration rate (TmP/GFR) was taken as a measure of renal phosphate handling in patients with good and stable functioning kidney allografts. TmP/GFR values were within the normal range in only one-fifth of the patients. Eighty per cent had an abnormally low renal phosphate threshold concentration. Persistent hyperparathyroidism was the causative factor of this diminished tubular reabsorption in less than half of these patients, the majority of them showing an iPTH independent phosphate leak. Although glucocorticoids, azathioprine and tubular damage of the graft in the perioperative phase may contribute to this iPTH independent phosphate wasting, no single causative factor could be identified. Cases with hypophosphataemia should be treated in order to avoid symptoms of phosphate depletion. Active Vitamin D metabolites would be the therapy of choice by suppressing the parathyroid glands ("chemical PTX") and by directly enhancing tubular phosphate reabsorption. In persistent hyperpathyroidism with hypercalcaemia, surgical parathyroidectomy must be considered. Therapy with phosphate salts is only symptomatic and should be used only as an adjunct.

Azathioprine↗
PubMed1978

[Median superior diastema--definition, etiology, symptoms].

The definitions, aetiology, and symptomatology of the diastema mediale superior are discussed in the present study on the basis of personal experience and reports in the literature, special attention being paid to the verbal evaluation of "genuine" or "spurious".

Diastema↗
PubMed1977

[Cases of clinical failures].

During the past 4 years, the Department of Health of the State of Berne received 91 complaints of patients about dental treatment. Most of the cases could be settled by proposals of the dental section of the state medical council. Most frequently crown and bridgework was the reason for complaints, secondly partial and complete dentures followed by restorative work and excessive grinding on teeth. Complete information of the patient about treatment possibilities, clear estimate of costs and referals for consultations would reduce the number of complaints.

Dentist-Patient Relations↗
PubMed1976

Intraction of aminoacyl-tRNA synthetases with ribosomes and ribosomal subunits.

Salt-washed ribosomes from rabbit reticulocytes stimulate seven partially purified aminoacyl-tRNA synthetases up to threefold: arginyl-, alanyl-, isoleucyl-, lysyl-, methionyl-, phenylalanyl- and valyl-tRNA synthetase. Both isolated subunits but not total ribosomal RNA show the stimulation. The increase in synthetase activity is also found in a highly purified Escherichia coli system employing homogenous (E. coli)phenyl-alanyl-tRNA synthetase and (E. coli)- tRNAPhe. The biological significance of the stimulation is discussed.

Amino Acyl-tRNA Synthetases↗
PubMed1976

[Results from a study of the normal values in the vertical, sagittal and transversal plane of early mixed dentitions].

168 (21.7%) of 776 pupils from primary classes in Jena had normal tooth position and occlusion. 94 of them were selected for a longitudinal study. Up to now, they have been examined at the ages of 7 and 8 years. The evaluation of the results obtained showed differences with regard to age and sex. The data reported and the deviations observed may be considered reference values. They concrete the assessment of the growth and development in the orofacial system, facilitate the recognition of dysgnathias which must be treated and optimize the planning and performance of orthodontic treatment.

Cephalometry↗