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Biomedical subjects

H Meyer

Publications and source records attributed to H Meyer.

At least 487 records · Page 27Linked to original sources
PubMed1977

Acute distal intestinal obstruction in gnotobiotic rats. Intestinal morphology and cell renewal.

1. Complete mechanical obstruction of the distal small intestine was produced in gnotobiotic rats. 72 h after the operation small intestinal morphology and epithelial cell renewal were investigated proximal and distal to the site of obstruction. 2. Proximal to the site of obstruction there were minor changes in villus height, base length and in villus cell number, a large increase in depth and diameter of the crypts and an approximately threefold increase in cell renewal. 3. Distal to the site of obstruction there were no differences between the intestines of rats with obstruction and controls. 4. The apparent lack of secretion by the goblet cells and the reduced number of intraepithelial leucocytes suggest that the barrier function of the small intestine is impaired in obstruction.

Animals↗
PubMed1977

Isolation and properties of prophospholipase A2 and phospholipase A2 from horse pancreas and horse pancreatic juice.

Two phospholipases A2 (EC 3.1.1.4) with different isoelectric points have been isolated from horse pancreas in high yield (880 mg/kg tissue). From pancreatic juice the more acidic species was isolated as the sole phospholipase A2. Upon tryptic activation the zymogens release a hepta- and pentapeptide, respectively from the N-terminal part of the protein giving rise to the formation of one single enzyme with a specific activity higher than that of pancreatic phospholipases A2 from other mammalian species. Horse phospholipase A2 differs from the porcine and bovine enzymes with respect to amino acid composition and kinetic properties. The sequence of the first 41 amino acid residues at the N-terminus has been determined by automatic Edman degradation.

Amino Acid Sequence↗
PubMed1977

Amino acid sequence of phospholipase A2 from horse pancreas.

The complete amino acid sequence of phosphlipase A2 (EC 3.1.1.4) from horse pancreas was determined. The protein controls of a single polypeptide chain of 125 amino acids and has a molecular weight of 13,927. The chain is crosslinked by seven disulfide bridges. The sequence was determined by automated Edman degradation of the intact protein and several of the large peptide fragments. Smaller peptides were analyzed by manual Edman degradation. Fragmentation of the peptide chain was accomplished by enzymatic digestion with trypsin, chymotrypsin, and thermolysin. The final overlap was found by digestion of the polypeptide with a staphylococcal protease specific for glutamoyl bonds. Phospholipase A2 from horse pancreas shows homology to snake venom phospholipases A2 and to the enzyme from porcine pancreas, provided that the published amino acid sequence of the porcine phospholipase A2 is revised to some extent.

Amino Acid Sequence↗
PubMed1977

Chromosome studies of bone marrow cells and peripheral blood lymphocytes from diphenylhydantoin-treated patients.

Chromosome studies were performed on both bone-marrow cells and peripheral blood lymphocytes from ten patients with epilepsy, treated with diphenylhydantoin alone. There was no evidence of chromosome damage. Furthermore, the bone-marrow smears from five of the patients were studied for the presence of micronuclei. There was no increase in the number of micronuclei compared with control persons. Conflicting results about the cytogenetic effect of diphenylhydantoin have appeared in the literature. It is emphasized that, in studies on the chromosome-damaging effect of chemical agents in man, bone marrow cells seem to be most indicative of the conditions in vivo.

Adult↗
PubMed1977

Structural adaptations of lactate dehydrogenase isozymes.

The three-dimensional structures of dogfish M4 (muscle) and pig H4 (heart) lactate dehydrogenase (L-lactate:NAD+ oxidoreductase, EC 1.1.1.27) have been determined and correlated with the amino acid sequences of the dogfish M4, pig M4, pig H4, chicken M4, and chicken H4 lactate dehydrogenase isozymes. These results have been related to the known differences of physicochemical properties between the M and H lactate dehydrogenase isozymes. By far the largest structural alterations occur in the transition between the "apo" and "ternary complex" conformational states of the enzyme rather than between species or isozymes. The major catalytic difference can be explained by a replacement of alanine (in the M chain) with a glutamine (in the H chain) in the vicinity of the binding site of the coenzyme phosphates. The known immunological differentiation of the M and H isozymes is consistent with the differences in their amino acid sequences.

Adenosine↗
PubMed1977

Arterial glucocorticoid receptors: the binding of tritiated dexamethasone in rabbit aorta.

Current concepts of the mechanism of the physiological action of both mineralocorticoids and glucocorticoids include an initial step in interaction between the steroid and specific receptors in the cytoplasm of target tissue cells. Using cells from rabbit aorta as a model system, we have studied the cytoplasmic binding of 3H-dexamethasone and 3H-aldosterone. Aorta cells appear to contain binding sites with a high affinity (Kd 4 degrees C approximately 1.3 X 10(-8) mol) for dexamethasone, and with specificity appropriate for glucocorticoid receptors. Under similar experimental conditions, mineralocorticoid receptors could not be demonstrated.

Aldosterone↗
PubMed1977

Local lymph node response in rats to allogeneic stimulus: analysis of the in vitro responding cells.

Parental strain rats were immunized in the footpads by F1 hybrid spleen cells. The draining lymph nodes were removed during the first 10 days after immunization and tested for mitogen responsiveness. Cell fractionation was performed by removal of macrophages, surface Ig positive, and F(c)-, and C3-receptor carrying lymphocytes. The depleted suspensions were tested in MLC to test the effect of lymphocyte subpopulations on the accelerated MLC response profile exhibited by the immune lymph node cells. Overall increase in mitogen stimulation was observed, but stimulation indices were slightly reduced as compared to non-immunized cells. Removal of phagocytic cells gave some increase in MLC response which was most pronounced when responder cells were tested during the first days after immunization. Depletion for non-T lymphocytes resulted in lowering of non-stimulated responder cell 14C uptake, whereas the specific accelerated MLC profile was unaltered or tended to improve acceleration. It is concluded from indirect evidence that T lymphocytes are the cell type responsible for the altered MLC kinetics, but that macrophages and non-T cells modify the response.

Animals↗
PubMed1977

The topography of porcine lactate dehydrogenase isoenzyme H4. The identification of lysines on the surface.

Porcine lactate dehydrogenase isoenzyme H4 was treated with methyl 6-(2,4-dinitrophenylamino)hexanimidate hydrochloride and the lysines modified hereby were identified. For this purpose 20 chymotryptic-tryptic N epsilon-[6-(2,4-dinitrophenylamino)hexanimidoyl]lysine containing peptides were isolated by means of gel chromatography, countercurrent distribution, thin-layer chromatography and ion-exchange chromatography. Their amino acid composition, the amino end groups and their electrophoretic mobilities were determined. With these data, the known primary structure of the procine lactate dehydrogenase isoenzyme H4 and the 6-A resolution structure analysis performed by Rossmann et al.[1] we identified the following lysines on the surface of the quarternary structure of the enzyme: no. 4, 6, 60, 77, 82, 121, 157, 179, 226, 230, 241, 306, 308, 316, 327 and 330. No modified lysine peptides were found in the intersubunit binding sites.

Amino Acid Sequence↗
PubMed1977

[The reaction of calves to parenteral administration of cyclopheosphamide].

One single injection of 50 mg/kg live weight cyclophosphamide or more to calves was followed by a latency of few days after which pneumonia or enteritis developed and caused death within one or two weeks. Cyclophosphamide application led to pronounced changes in the white blood count characterised, at the beginning, by rise of neutrophilic granulocytes and decline of lymphocates. Primary rise of granulocytes then was followed by almost complete disappearance of them. In those calves that survived the parameters of the white blood count were not restoredto normal until several weeks had elapsed. While an injection of 30 mg/kgcyclophosphamide usually was tolerated without any visible clinical reaction, it was also accompanied by the above pronounced changes in the white blood count. The activity of the reticulohistiocytary system, as recordable by means of ink and bacterial clearance, was not markedly affected by one single injection of 30mg/kg or 40 mg/kg cyclophosphamide. Calves with cyclophosphamide treatment exhibited unambigous humoral immune response, yet somewhat delayed or reduced in comparison to controls. While one single intravenous injectionof 30 mg/kg cyclophosphamide alone failed to trigger any clinical disease, it proved to be capable of rendering calves more susceptible to pneumonia pathogens. It, therefore, might be suitable for supporting experimental infection and thus facilitating the study of enzootic pneumonia of calf which usually is difficult to reproduce.

Animals↗
PubMed1977

[Studies on calf salmonellosis. 3. Preclinical evaluation of a Smd. Salmonella dublin live vaccine].

Results of preclinical assay, preparation and conservation of a S.-dublin live vaccine based on streptomycin dependent mutants and for oral application are demonstrated and discussed in detail. The used oral vaccine is very good tolerated by calves and results in stable immunity after administration of a daily dose of 5 x 10(10) bis 1 x 10(11) living Smd.-mutants for 10 consecutive days. Complete immunity developes in calves within a period of two weeks after the last antigen administration and persists up to the age of 5 to 6 months. Conserving the vaccine at low temperatures (-15 degrees C) the number of living organism is far-reaching preserved in the first 5 months after preparation. After thawing the vaccine is to be used within a period of 3 days. With respect to the preparation of the live vaccine on semisynthetic nutritiv media some informations are given concerning the improvement of bacterial yield.

Administration, Oral↗