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Biomedical subjects

G Schmidt

Publications and source records attributed to G Schmidt.

At least 613 records · Page 34Linked to original sources
PubMed1976

Presence of rfe genes in Escherichia coli: their participation in biosynthesis of O antigen and enterobacterial common antigen.

In Salmonella, ilv-linked rfe genes participate in the biosynthesis of the enterobacterial common antigen (CA) as well as of certain types of O antigen (serogroups C1 and L). rff genes, probably in the same cluster with rfe, are required for CA synthesis (P.H. Mäkelä et al., in preparation). Several Escherichia coli strains were studied to determine whether they also have rfe-rff genes that are involved in the synthesis of O antigen and CA, or of CA only. In a first approach, E, coli K-12 F-prime factors carrying the genes ilv and argH or argE and presumably rfe-rff genes were introduced into CA-negative Salmonella mutants that are blocked in CA synthesis because of mutated rfe or rff genes. All resulting ilv+ hybrids were CA positive. In recipients with group C1-derived rfb genes, the synthesis of O6,7-specific antigen was also restored. This result shows that E. coli K-12 has rfe and rff genes providing the functions required in the synthesis of CA and Salmonella 6,7-specific polysaccharide. By introduction of defective rfe regions from suitable Salmonella donors into E. coli O8, 09, and O100 strains, the synthesis of CA as well as of the O-specific polysaccharides was blocked. This indicates that in the E. coli strains tested the rfe genes are involved in the synthesis of both O antigen and CA. This suggestion was confirmed by the finding of E. coli rough mutants that had simultaneously become CA negative. In transduction experiments it could be shown that the appearance of the rough and CA- phenotype was due to a defect in the ilv-linked rfe region.

Antigens, Bacterial↗
PubMed1976

Enterobacterial common antigen in rfb deletion mutants of Salmonella typhimurium.

The his-rfb deletion series of Salmonella typhimurium mutants characterized previously by Nikaido et al. was examined for the presence of the enterobacterial common antigen (ECA). All deletions not extending further to the left than the genes for cytidine phosphoabequose synthesis were ECA positive, whereas longer deletions (extending to the genes for thymidine diphosphorhamnose synthesis or further) were ECA negative. When these long-his-rfb deletion strains were studied further, it became clear that they (four out of four studied) had accumulated a second mutation, called rff, close to ilv, which prevented the synthesis of ECA. When rff- was replaced by rff+, the recombinants, now having the his-rfb deletion only, produced traces of ECA, showed reduced viability, increased sensitivity to sodium dodecyl sulfate (SDS) and to a lesser extent, to other anionic detergents, and accumulated secondary "suppressor" mutations upon storage. Such suppressor-containing mutants could be isolated by selecting for resistance to 1% SDS. Thirty of 46 SDS-resistant mutants studied had a second mutation, which alone prevented the synthesis of ECA, close to ilv. This ilv-linked mutation was similar to the rff mutation of the strains studied originally. The new rff mutation was similar to previously described rfe mutations in its close linkage to ilv and association with an ECA-negative phenotype. It differed from rfe, however, by not affecting the synthesis of the O antigens (O-6,7) of group C1. In Salmonella group C1, all ECA genes identified thus far are linked to ilv (rfe and/or rff) and none is linked to rfb.

Antigens, Bacterial↗
PubMed1976

[Combined anesthesia with propionylpromazine (Combelen) and methadone (Polamivet). A sure simple method of anesthesia in gastrointestinal surgery in dogs].

In more than 400 cases of gastrointestinal surgery on mongrel dogs, a combination anesthesia of a neuroplegic agent--propionyl promazine (Combelen) and methadone (Polamivet), an analgesic--was administered without additional intubation or ventilation. This type of anesthesia is simple to apply and practically without risk; the conditions for the operation are therefore excellent. No monitoring personnel is required, no intra- or post-operative incidents have occurred. Thus this method may be recommended as safe and simple for experimental abdominal surgery in dogs.

Anesthesia, Intravenous↗
PubMed1976

Purification of a human serum protein ("factor E") which enhances cobra venom factor-induced indirect lysis. Identification with the fifth component of complement.

Complexes formed of Cobra venom factor (CVF) and activated factor B (B) by interaction of CVF and B with trypsin or factor D are capable of activating the third and fifth complement component. When incubated with sheep or guinea pig red cells and guinea pig serum in the presence of EDTA, these CVFB complexes produce "indirect lysis". Addition of a human serum factor, earlier designated as factor E (6), greatly enhances the efficiency of this lytic system. The component with this activity has been purified to homogeneity (disc and immunoelectrophoresis). In chromatographic fractionations it was inseparable from the fifth complement component, it was inactivated by and reacted with several anti-C5 antisera, and kinetics of inactivation by heat (56 degrees C) and trypsin were the same for factor E and hemolytic C5 activities. It is concluded that factor E is the fifth component of human complement. Guinea pig C5 is not capable of supporting indirect lysis in a comparable manner, for as yet unknown reasons. Some possible explanations are discussed.

Animals↗
PubMed1976

Incompatibility between C3b and B of guinea-pig and man and its influence on the titration of the alternative pathway factors D and B in these two species.

The incubation of the proteins C3b, B, D and C3 induces enzymatic activation of B and of C3. This system of purified components was applied to the titration of the guinea-pig and human factors D and B in various homologous and heterologous reaction mixtures. On the basis of functional as well as of immunological tests, the D enzymes of both species were found to be related proteins. First, titrations of factor B revealed that both D enzymes activate homologous and heterologous B with comparable efficiency. Secondly, a rabbit anti-D antiserum raised against guinea-pig D was found to form a precipitation line of partial identity with guinea-pig and human D. In contrast to the compatibility between heterologous D and B, heterologous combinations of C3b and B were found to be incompatible. This incompatibility was indicated by low titres of D in the presence of heterologous C3b and B; in contrast, in the presence of homologous C3b and B, the titres of D were up to one hundred-fold higher. The reason for this effect was found to reside in inefficient complex formation between heterologous C3b and B. Therefore titrations of D and B should be only performed in the presence of homologous C3b and B.

Animals↗
PubMed1976

[Characterization and spinning of alkaline solutions of wheat protein and casein].

The viscosity behaviour of alkaline solutions of mixtures from different wheat glutens with casein in dependence on the concentration of the whole protein, wheat protein, sodium hydroxide, sodium chloride and on the temperature, time and the effect of treatment of wet wheat gluten with sodium chloride or sodium hydroxide on the properties of the spun wheat protein/casein fibers are described. Based on this model experiments the rheological behaviour of alkaline solutions of wheat protein/casein (I:2) and proceed from the parameters of the spinning process the properties of the corresponding spun fibers are represented.

Caseins↗
PubMed1975

[Raised cAMP content of striated muscle in experimental chronic renal failure (author's transl)].

3', 5'-Adenosine monophosphate (cAMP) levels were determined in skeletal and heart muscle tissue of rats in chronic renal failure. Compared to normal animals no alteration in cAMP concentration was observed in heart muscle, whereas the cAMP levels in skeletal muscle were increased by 34%. This cAMP rise may be caused by the elevated plasma catecholamines, glucagon or parathyroid hormone levels in uraemia. The results suggest that the increased cAMP levels in skeletal muscle of rats in chronic renal failure contribute to the raised cAMP levels in the plasma.

Animals↗
PubMed1975

[Vitamin A absorption test. I. Pancreatic insufficiency and sprue (author's transl)].

The vitamin A absorption test and its interaction with the secretin-pancreozymin test, the d-xylose absorption test, fecal fat content and the small intestine biopsy are estimated on their significance in the diagnosis and course of sprue and pancreatic insufficiency. The investigation includes 39 patients with different stages of pancreatic insufficiency and 10 patients with sprue. First it results relatively wide spread normal values in a control collective with sometimes unexplained low values, the significance of the vitamin A absorption test as screening test therefore is limited. Secondly the absent rise after vitamin A ingestion in serum after 3 and 6 hours favours the diagnosis of sprue, correlates with the histological findings of the mucosa and appears more reliable than the d-xylose test. Thirdly this test seems to allow the differentiation between malabsorption and maldigestion when steathorroe is proved: In contrast to sprue-syndromes pancreatic insufficiency shows significant reduced 3 hour values at subnormal 6 hour values after vitamin A ingestion.

Adult↗
PubMed1975

[Vitamin A absorption test. II. Diseases of the liver, the extrahepatic biliary system and the stomach (author's transl)].

It is reported on the estimation of the vitamin A absorption test in 17 patients with chronic liver diseases, 26 patients with diseases of the extrahepatic biliary system, and in 12 patients with diseases of the stomach. In the latter there are no changes in the vitamin A test. On the contrary patients with diseases of the liver and biliary system show differences in the serum vitamin A levels. A separate consideration of active liver cirrhosis and active cholangitis indicates individualities in the constellation of the 3 and 6 hour values after vitamin A ingestion: in liver cirrhosis the first value is normal while the 6 hour value seems significant lowered so that the maximum vitamin A concentration is found near 3 hours. In active cholangitis both values are reduced, the first one more than the second one. The reason is to be seen in a decrease of the conjugated bile acids, whereas in the group of liver diseases an interpretation is somewhat problematic. It is to discuss whether these results depend on the development of portal hypertension, while the intestinal absorption seems normal and liver damage only of secondary importance. The fact that this test is influenced by diseases of the liver and biliary system shortens its significance as a screening test for malabsorption or maldigestion though a further differentiation between sprue and pancreatic insufficiency seems possible.

Adult↗
PubMed1975

The action of staphylococcal nuclease (EC-number 3. 1. 4. 7.) on thymus nucleohistone (TNH) and on some nucleoprotamines.

The biphasic nature of the time course of the action of staphylococcal nuclease on thymus nucleohistone was confirmed by studying the hydrolysis of this nucleoprotein at various enzyme concentrations. The transition from the rapid first to the sluggish second phase of the time course was particularly distinct at the highest enzyme concentrations. The rapid initial phase of the hydrolysis curve leveled off sharply when between 60 and 65 per cent of the total TNH phosphorus had been converted to acid-soluble phosphorus compounds. The insoluble complexes of TNH with protamines were found to be very resistant against the action of staphylococcal nuclease. The time course of the action of staphylococcal nuclease on a commercial nucleoprotamine of salmon testicles was found to become very sluggish when between 35 and 40 per cent of its total phosphorus had been converted to acid-soluble phosphorus compounds. When nucleoprotamines prepared in the laboratory from the secreted sperm cell suspension of Brown Brook Trout were digested with staphylococcal nuclease, only between 15 and 20 per cent of the total phosphorus were cleaved to acid-soluble phosphorus compounds during the rapid phase of the nuclease action. The respective values for the phosphorus fractions available for magnesium-binding and those susceptible to the rapid cleavage by staphylococcal nuclease were found to be very similar.

Animals↗