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Biomedical subjects

S Schmidt

Publications and source records attributed to S Schmidt.

At least 505 records · Page 28Linked to original sources
PubMed1977

Proteolytic and transhydrogenolytic activities in isolated pancreatic islets of rats.

In homogenates and subcellular fractions of pancreatic islets of Wistar rats we could demonstrate three groups of protein degrading enzymes. The proteinases of group 1 are characterized by both trypsin-like and carboxypeptidase B-like specificities with slightly acid pH optima (pH 5.5-6.5) and seem to play important roles in the conversion of proinsulin into insulin. The properties suggest that these enzymes localized in the secretion granule/mitochondria fraction are related to the tissue cathepsins. Group 2 enzymes are thiol-depending proteinases with a pH optimum at 7.0 occuring mainly in the cytosol and to a lesser extent in the fraction of nuclei and cell debris. Group 3 represents the thiol protein oxidoreductase with a pH optimum of 7.0. This enzyme degrading disulfide bonds could also be important in the formation of the disulfide bonds during protein folding after synthesis.

Animals↗
PubMed1976

Demonstration of insulin degradation by thiol-protein disulfide oxidoreductase (glutathione-insulin transhydrogenase) and proteinases of pancreatic islets.

Homogenate preparations of pancreatic islets have been found to degrade insulin by cleavage of the interchain disulfide bonds, followed by proteolysis of the resulting A and B chains. A proteolytic system of the pancreatic islets splitting not only 125I-labeled insulin A chain but also 125I-labeled glucagon at pH 7.0, was shown to be activated by glutathione and inhibited by EDTA. The results suggest that pancreatic islets contain both the thiol-protein disulfide oxidoreductase (glutathione : protein-disulfide oxidoreductase, EC 1.8.4.2) and the A and B chain-degrading enzyme(s). The effects of EDTA argue against the implication of cathepsins in insulin breakdown under the experimental conditions employed.

Amylases↗
PubMed1976

Comparison of deaf and hearing children on body-object localization.

20 profoundly deaf and 20 normal hearing children from ages 10 to 13 were compared as to their ability to locate visually the position of apparent vertical and the apparent location of the longitudinal axis of the body under erect and 30 degrees left and right body-tilt. Both deaf and normal hearing children were able accurately to locate a rod to the apparent visual vertical, but deaf children were significantly more accurate in aligning a rod to their apparent body-position than hearing children. This finding is discussed from both a learning view and from a hypothesis of developmental lag.

Adolescent↗
PubMed1975

[Immuno-prevention of coli infections in swine using live vaccine. 1. Use in coli infections during the 1st days of life].

Live vaccine prepared from streptomycin-dependent mutants of E. coli was well tolerated in various doses and at various times of administration, for there were no adverse reactions. There was no evidence of reversion to a virulent form. Efficacy was closely related to frequency of application of the vaccine. Vaccination must be performed as early as possible to immunize against infection during the first few days of life. It was possible to confer protection against the diarrhoea that occurs at 3-4 weeks of age. The use of an oral vaccine under intensive husbandry systems was shown to be safe. When the piglets were kept in cages, the vaccine could be administered in the existing mixing tanks for water supply, without the need for special equipment. Oral immunization of pigs already infected or already ill did not aggravate the existing infection, whether the animals were housed individually or in pens. Because of the dilution effect of the mixing tank and water supply pipes, the dose of vaccine, given on ten successive days, should be calculated at 10(9) organisms of the E. coli mutant per animal. This should supply a number close to the desired bacterial count of 10(10) organisms per animal daily. Immunization significantly reduced the frequency of gastrointestinal diseases during the first three weeks of age in piglets.

Animals↗
PubMed1975

Changes in labeling of soluble and solubilized rat brain proteins using (3H)-leucine as precursor during a learning experiment.

This paper deals with an electrophoretic study on soluble and solubilized rat brain proteins during a brightness discrimination. After intraventricular injection of L-[3H]-leucine the most pronounced increase in relative specific activity was found for several soluble acidic protein-band complexes as well as for solubilized slow-migrating non-myelin proteins obtained from hippocampus of trained animals over the data obtained for active and passive controls.

Animals↗
PubMed1975

Changes in labeling of soluble and insoluble rat brain proteins using [3H]-tyrosine as precursor during a learning experiment.

The incorporation of intraventricularly injected L-[3H]-tyrosine into proteins from three rat brain regions was studied during the acquisition of a shock-motivated brightness discrimination. Separating the proteins by means of polyacrylamide gel electrophoresis revealed an increased labeling confined to only a few of the resolved slow-moving bands of soluble and, especially insoluble hippocampus proteins. The labeling of visual cortex proteins showed only minute changes, while the auditory cortex proteins exhibited no differences between trained and nontrained animals.

Animals↗
PubMed1975

[The influence of experimental diabetes on the distribution of LDH-isoenzymes in rat skeletal muscle (author's transl)].

The distribution of LDH-isoenzymes from homogenate-supernatant of M. soleus of normal and streptozotocin-diabetic male rats was investigated by agargel-electrophoresis. Five LDH-isoenzymes could be detected in the M. soleus of normal rats; the average proportion of H-subunits was 69.1% (age 3-4 month) resp. 69.6% (age 13 month) from the total value. In male rats of the same age a mild diabetes was induced by intravenous injection of 65 mg streptozotocin per kg body weight. In the M. soleus of these animals also 5 LDH-isoenzymes were detected. After 1-2 month duration of diabetes the LDH1 is decreased from 30.3% of controls to 18.2% and the LDH4 is increased from 11.1% of controls to 20.1%. The H-subunit value decreased to 61.9% from the total value. In long term diabetes (11 month) the values of single fractions and the H-subunit value did not differ from those of controls. The findings are discussed considering the composition of M. soleus on different fiber types and the influence of diabetic conditions.

Animals↗
PubMed1975

Mixed lymphocyte culture stimulatory and responding capacity of lymphocytes from patients with lymphoproliferative diseases.

Lymphocyte reactivity in vitro was studied in patients with Hodgkin's disease, chronic lymphocytic leukaemia and lymphosarcoma. The responding capacity to phytohaemagglutinin (PHA) was markedly depressed and delayed in all three groups of patients compared with the PHA response observed in lymphocyte cultures from normal individuals. In one-way mixed lymphocyte culture experiments a significant decrease in responding capacity of the patients' lymphocytes to lymphocytes from normal donors could be demonstrated. In contrast, the stimulatory capacity of the patients' lymphocytes was found to be intact, or only slightly reduced.

Adolescent↗