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Biomedical subjects

G Richter

Publications and source records attributed to G Richter.

At least 289 records · Page 16Linked to original sources
PubMed1976

Comb-like derivatives of amylose having (1-6)-linked malto-oligosaccharide side-chains.

The preparation of acetylated glycosyl bromide derivatives of the higher malto-oligosaccharides was studied by using beta-cyclodextrin or linear malto-oligosaccharides of d.p. 6 and 7. The products were treated with 2,3-di-O-phenylcarbamoyl-6O-tritylamylose in the presence of silver perchlorate (reaction A), and with 2,3-di-O-phenylcarbamoylamylose in the presence of mercuric cyanide and mercuric bromide (reaction B). After removal of the substituents, the branched molecules were characterized by their iodine-binding properties, beta-amylolytic degradation, and their priming activity in phosphorolytic synthesis. The distance between the branch points of the backbone chain was 25-55 and 100-150 units in the products from reactions A and B, respectively. Thus, the frequency of branching was considerably lower than in the comb-like molecules having D-glucose side-chains previously described.

Binding Sites↗
PubMed1976

Animal experiments with biogalvanic and biofuel cells.

Animal experiments with biogalvanic cells have demonstrated that an average power of 80 muW can be derived continously for at least 2 years. There is a further scope to stabilize the power at 100 muW for considerable longer periods so that the chances of cardiac pacing with biogalvanic power have become bright. However, large scale efforts are necessary in in establishing the statistical reliability and the secured performance which are expensive and time consuming. Animal experiments with biofuel cells are still in preliminary stages. We derived a continous power of 40 muW (4MUW/cm2) at 575 mV over 150 days so far. This is the longest recorded period with such a high power density. The main problem in deriving higher power over longer period is to properly encapsulate the cell with materials which are hydrophilic and essentially biocompatible.

Animals↗
PubMed1976

[Etiology and morbidity of drug exanthemas from a clinical viewpoint].

After a brief discussion of the potential errors and uncertainies of statistics about etiology and epidemiology of drug eruptions the 144 cases, seen from 1968 to 1974 in our dermatological clinic, are analysed and compared with the data from the years 1957 to 1965 respectively the quantities of special drugs, consumed during one year in Dresden city. The results are: significant increase of drugs eruptions (from 0,9% in 1957 to 1965 to 1,9% in 1968 to 1974) among the hospitalised patients; absolute and relative increase of penicillin- (36,7%) and chloramphenicolreactions (21,6%) combined with a decreasing importance of sulfonamides and barbiturates among the causes of drug rashes; increase of urticarial - and decrease of fixed exanthemas: a yearly frequency of 3 to 4 clinically treated ore diagnosticated drug eruptions/100 000 inhabitants respectively 1 to 2 chloramphenicol and 1--5 penicillin-rashes/10 000 treatments. Even if only 10% of the drug eruptions are diagnosticated by us and 90% in other clinics or ambulances the frequency of penicillin-rashes merely amounts to 1 to 5%.

Barbiturates↗
PubMed1976

[Group-allergic reaction spectrum and sensitization potency of benzylisothiocyanate].

Allergenicity of benzylisothiocyanate and group-allergic cross reactions. Comparative patch-test series made in pateints suffering from contact dermatitis induced by Sulbentin (Dibenzthion)-antimycotics and in guinea pigs, experimentally sensitized to benzylisothiocyanate (BITC), showed: BITC is a potent contact sensitizer and the real hapten in cases of Sulbentin-allergy. Of special importance in this molecule is the benzyl-group. Neither 4,4-diphenylmethandiisocyanate and isophorondiisocyanate (substances used in polyurethane production) nor the closely related methylisothiocyanate (decomposition product of some potato-selecting agents) produced any groupallergic cross reactions in the above-mentioned patients and guinea pigs.

Animals↗
PubMed1975

[Subclavian vein catheterization].

On the basis of experiences with more than 500 catherizations of the subclavian vein, which were performed partly infraclavicularly, partly supraclavicularly, the two methods were critically estimated and compared with regard to their effectivity and complications. The range of indications is enlarged from the access through the veins for taking blood samples and the infusion therapy over the measurement of the central venous blood pressure to the floating catheterization, temporary external pacemaker stimulation and emergency dialysis. The mastering of the two techniques of puncture provides a high measure of security for the emergency case. On the assumption of an approach secundum artem and knowing and taking into consideration the possibilities of complication, which are particularly referred to, the two ways seem to be approximately of the same value.

Catheterization↗
PubMed1975

Properties and subunit composition of RNA polymerase II from plant cell cultures.

The purification of DNA-dependent RNA polymerase II (EC 2.7.7.6) from plant cell cultures of Petroselinum (parsley) is described. The procedure during which enzyme I is eliminated includes initial precipitation with (NH4)2SO4, an ultracentrifugation step, gel filtration on Sepharose 4B, chromatography on DEAE-cellulose, DNA-agarose and DEAE-Sephadex. The enzyme purified almost to homogeneity exhibits maximal activity with denatured DNA, and is activated preferentially by Mn2+; alpha-amanitin acts as a strong inhibitor. Electrophoresis of the enzyme in the presence of dodecylsulphate indicates that it is composed of seven subunits with mol. wts of 200 000, 180 000, 140 000, 43 000, 26 000, 25 000 and 16 000. The results of molecular weight and molar ratio determinations suggest that Petroselinum RNA polymerase II may exist in two active forms differing only in the composition of their high molecular weight subunits.

Amanitins↗
PubMed1975

[Primary malignant nephrosclerosis (author's transl)].

Primary malignant nephrosclerosis shows a haemolytic-uraemic symptomatology and can be differentiated from secondary malignant nephrosclerosis on clinical and histological grounds. The disease was observed in 4 patients: a 25-year-old man and 3 women aged 19, 28 and 49 years. The disease is characterized by a fulminating course, malignant hypertension with progressive retinopathy, and development of progressive renal failure with subsequent irreversible anuria. In addition haemolytic anaemia or posthaemolytic states as well as consumption coagulopathy occur. In 2 cases schizozytes and in particular helmet-shaped forms could be demonstrated. On histology an obliterating necrotizing vascular change is seen which is limited to the kidneys as was demonstrated in one case by angiography. Therapeutic attempts included antibiotics, steroids, heparin, streptokinase, antihypertensive drugs, and haemodialysis. The 3 female patients died, the man survived after bilateral nephrectomy.

Acute Disease↗
PubMed1975

[Studies on the protein and amino acid metabolism of laying hens using 15N labeled casein. 2. 15N incorporation into the N fractions and basic amino acids of the hen stomach and into the contents of the crop and stomach].

4 colostomated laying hens received 15N labelled casein as sole protein source for a period of 6 days. Two birds each were slaughtered on the 8th and 12th day of experiment. 23.5% of the total N in the glandular stomach and the gizzard were TCE soluble. The amino acid composition of the gastric proteins was broader than that of the proteins of flesh, with the exception of lysine and histidine. The atom % 15N' of the N of the stomach was roughly the same as that of the protein N; the level of labelling in the TCE soluble N fraction was only slightly higher. 2 and 6 days after the final administration of tracer N an appreciable proportion of 15N was found in the N fractions and in the basic amino acids contained in the crop and the stomach. From this is may be concluded that a considerable portion of the N-containing substances previously absorbed were secreted into the lumen of the crop and the stomach.

Amino Acids↗
PubMed1975

[Studies on the protein and amino acid metabolism of laying hens using 15N labeled casein. 15N concentration in the intestinal content and intestinal tissue in relation to the time of the last 15N administration].

Four laying hens with anus praeternaturalis were fed 15N casein for a period of 6 experimental days. Each experimental bird thus received a 15N excess (15N') of 154.44 mg. 11.54 mg of 15N' were found in lysine 3.99 mg in histidine and 9.58 mg in arginine. 2 hens were slaughtered 48 hours after the last 15N dose; another 2 were sacrificed after 144 hrs. In this investigation the N content of the intestinal contents and in the proteins of the small and large intestine were determined. The average N content of the small intestine per hen 2.65% that of the large intestine, 2.60% and, correspondingly, the TCE soluble proportion of N was 21.8% and 20.4%. The percentage of amino acids in the contents of the small intestine was found to change relative to that of the dietary proteins, approximating the protein composition of the intestine. In the first two hens the atom % 15N' was found in the different sections of the intestine and in the intestinal contents varied between 0.14 and 0.28. The data obtained from the two hens slaughtered 144 hours after the last 15N' dose were nearly the same ranging from 0.08 to 0.10 atom % 15n'.

Amino Acids↗
PubMed1975

[Studies on the protein and amino acid metabolism of laying hens using 15N labeled casein. 4. Fecal excretion of nitrogen and amino acids, digestibility of crude protein and absorption of basic amino acids].

Generally, the faeces of laying hens fed 15N casein rations were found to contain equal proportions of TCE-precipitable and TCE-soluble nitrogen. Considerable variations were observed to occur between the 64 samples investigated (27%-75%) and no explanation was found to account for this fact. The content of basic amino acids in faecal proteins was found to differ considerably from that of the proteins in the intestinal contents. A high lysine content was found after the feeding of wheat. The present trial substantiated this result, provided the casein contained a certain proportion of non-available lysine. The apparent and true digestibility of dietary N was 88% or 91%, that of 15N (2nd and 6th day of experiment) and 92%. During the feeding of labelled casein a higher level of N labelling was found in the TCE-soluble portion of the faeces, whereas on the 8th to 12th day a higher level of labelling was observed in the TCE-precipitable portion of the faeces. The peak of 15N excretion occurred on the 3rd day of experiment. When 15N administration terminated the atom% 15N in the faeces and in urine was found to decrease rapidly approximating the initial level of labelling asymptotically.

Amino Acids↗
PubMed1975

[On the pressure-volume relation of the central and the peripheral vascular bed of the low pressure system (author's transl)].

The effect of hemorrhage amounting 420 ml in relation to the behaviour of the pressures and volume of the intrathoracic and extrathoracic compartment was studied on 10 young male adults. The volume elasticity coefficient E' and the vascular compliance 1/E' of the intrathoracic, extrathoracic and the total circulation were calculated as a result of the change in pressure and volume after the 420 ml hemorrhage. The coefficient of the volume elasticity for the intrathoracic compartment was found to be 23 dyn-cm-minus 5, for the extrathoracic compartment 15 dyn-cm-minus 5 and for the total circulation 9 dyn-cm-minus 5. The compliance of the intrathoracic compartment was 0.8 ml/mm Hg/kg BW, that of the extrathoracic compartment was 1.2 ml/mm Hg/kg BW and that of the total circulation was 2.0 ml/mm Hg/kg BW. These findings support the thesis of the large distensibility of the intrathoracic compartment.

Adult↗
PubMed1975

[Examination of sinoatrial conduction through premature atrial stimuli via the esophagus].

Sinoatrial (SA) conduction can be tested in man by premature atrial stimuli. The difference between the post-extrasystolic pause and the spontaneous sinus cycle is a sign of the sinoatrial delay. Extern atrial stimuli provoked over the esophagus showed analogous results to intracardiac tests. The sinoatrial conduction time estimated by the esophagus method is about 20 ms higher. In 30 normal persons it was 95 +/- 36 ms (x +/- 2 SX). 7 patients with sick sinus syndrome showed aberrations as in the intracardiac test. Different types of sinoatrial block should be distinguished. Type I measured by the esophagus method had a "SAE time" over 130 ms. Type II always had compensating postextrasystolic pauses due to higher SA delay. Type III of other authors could not be observed; there are doubts about the rightness of this type. In 2 patients SA blocks over several sinus cysles could be induced by premature stimuli. This feature osberved for the first time has been declared as type IV. In 28 patients with different diseases of the heart type I could be found 12 times and type II 6 times; SA block was not known previously. The calculation of the SA time by atrial stimuli via the esophagus offers a riskless and simple method for the further differential diagnosis of disturbances of the cardiac rhythm.

Adult↗
PubMed1975

[RNA and protein biosynthesis in toluene treated E. coli B].

The conditions for RNA- and protein synthesis in toluenized E. coli B are investigated. The kinetics of RNA- and protein synthesis indicate that a coupled synthesis of both macromolecules takes place in these preparations. Treatment with 1% Brij 58 alters the permeability of toluenized E. coli in such a way that the protein synthesis depends on the addition of supernatant proteins (chromotographed S100 from E. coli) and tRNA.

Bacterial Proteins↗