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Biomedical subjects

R Wagner

Publications and source records attributed to R Wagner.

At least 487 records · Page 27Linked to original sources
PubMed1980

[Histological and enzyme histochemical studies of intestinal interposition after total gastrectomy].

The formation of a stomach substitute with various intestinal interpolations (jejunum, ileocecum, colon) and the esophagojejunostomy by a Roux-anastomosis are carried through after total gastrectomy in animal experiments. The structural rebuilding proceedings in the intestinal interpolations were histologically and enzyme-histochemically examined after an experimental time of 3 months. A dilatation of the intestinal wall in connection with muscular wall hypertrophy appears in all operating method. In that way the reservoir function is guaranteed in the various stomach substitutes. The mucosa of the jejunal interpolation shows a hyperregeneratoric atrophy. A small enlargement of the surface originates in the colon interpolation from a villiferous conversion of the proximal parts of the crypts. The advance of the activity of the brush border enzymes in the ileocecum and the colon interpolation refers to an attempt of the mucosa on a change of the conditions of resorption. The essential pathogenetic factor of all rebuilding events appears in the intralumic environmental alteration in the intestinal interpolations.

Animals↗
PubMed1979

Phase transition characteristics of diphosphatidyl-glycerol (cardiolipin) and stereoisomeric phosphatidyldiacylglycerol bilayers. Mono- and divalent metal ion effects.

Synthesis and phase transition chaaracteristics of aqueous dispersions of the homologous (12 : 0, 14 : 0, 16 : 0) diphosphatidylglycerols (cardiolipins) and phosphatidyldiacylglycerols are reported. Electron microscopy of the negatively stained aqueous dispersions reveals a characteristic lamellar structure suggesting that these phospholipid molecules are organized as bilayers in the aqueous dispersions. The phase transition temperature (Tm) and the enthalpy of transition (delta H) increase monotonically with chain length in the cardiolipin and phosphatidyldiacylglycerol series; Tm for phosphatidyldiacylglycerol is higher than that for cardiolipin of the same chain-length. The transition temperatures for the enantiomeric sn-3,3- and sn-1,1-phosphatidyldiacylglycerol and for the diastereomeric, meso-sn-1,3-phosphatidyldiacylglycerol are approximately the same. The molar enthalpy for the transition of cardiolipin-NH+4 bilayers is approximately twice the value for the phosphatidylcholines of the same chain length, i.e., the molar enthalpy per acyl chain is approximately the same in the two systems. The transition temperatures for metal ion salts of C16-cardiolipin exhibit a biphasic dependence upon the unhydrated ionic radii, i.e., the highest Tm is observed for Ca2+-cardiolipin and decreases for the salts of ions with smaller and larger ionic radii than that of Ca2+. The lowest Tm is observed for Rb+-cardiolipin. Monovalent metal salts of cardiolipin exhibit two phase transitions. This effect may result from different conformational packing of the four acyl chains due to differences in metal-phosphate binding.

Cardiolipins↗
PubMed1979

A ribonuclease-resistant region of 5S RNA and its relation to the RNA binding sites of proteins L18 and L25.

An RNA fragment, constituting three subfragments of nucleotide sequences 1-11, 69-87 and 89-120, is the most ribonuclease-resistant part of the native 5S RNA of Escherichia coli, at 0 degrees C. A smaller fragment of nucleotide sequence 69-87 and 90-110 is ribonuclease-resistant at 25 degrees. Degradation of the L25-5S RNA complex with ribonuclease A or T2 yielded RNA fragments similar to those of the free 5S RNA at 0 degrees C and 25 degrees C; moreover L25 remained strongly bound to both RNA fragments and also produced some opening of the RNA structure in at least two positions. Protein L18 initially protected most of the 5S RNA against ribonuclease digestion, at 0 degrees C, but was then gradually released prior to the formation of the larger RNA fragment. It cannot be concluded, therefore, as it was earlier (Gray et al., 1973), that this RNA fragment contains the primary binding site of L18.

Base Sequence↗
PubMed1979

The mechanism of epithelial shedding after ischemic damage to the small intestinal mucosa. A light and electron microscopic investigation.

The intestinal mucosa of the rat was examined by light and electron microscopy 15, 30, 60 and 120 min after complete ligation of the vessel arcades of the proximal jejunum. The characteristic sign of ischemic damage to the small intestinal mucosa and the reason for epithelial shedding is the appearance of membrane enclosed cytoplasmic blebs which arise at the cell base of the enterocytes and detach the epithelium from the basement membrane. This process begins at the tip of the villi before the enterocytes display signs of irreversible damage and progress to the base of the villi with continuation of the ischemia.

Animals↗
PubMed1979

Selenium requirement for active xanthine dehydrogenase from Clostridium acidiurici and Clostridium cylindrosporum.

The xanthine dehydrogenase of Clostridium acidiurici and C. cylindrosporum was assayed with methyl viologen as acceptor. In C. acidiurici the basal activity level was about 0.3 mumol/min x mg of protein. Cells grown on uric acid in the presence of 10(-7) M selenite showed a 14-fold increase in xanthine dehydrogenase activity, which decreased with higher selenite concentrations (10(-5) M). The supplementation with 10(-7) M molybdate or tungstate was without effect. High concentrations of tungstate decreased the xanthine dehydrogenase if selenite was also present. In comparison, high concentrations of molybdate affected only a small decrease in activity level at the optimal concentration for selenite and relieved to some degree the inhibitory effect of 10(-5) M selenite. With hypoxanthine and xanthine as substrates for growth again only the addition of selenite was necessary to show a similar increase in xanthine dehydrogenase activity. C. acidiurici could be grown in a mineral medium. Both xanthine dehydrogenase and formate dehydrogenase exhibited the highest level of activity if selenite and tungstate were present in that medium. In C. cyclindrosporum the basal activity level of xanthine dehydrogenase was about 0.95 mumol/min x mg of protein. The addition of 10(-7) M selenite to the growth medium increased the activity level about 3-fold, but the highest level (3.7 U/mg) was reached if 10(-7) M molybdate was also added. The presence of tungstate resulted in a decreased enzyme activity.

Cell-Free System↗
PubMed1979

Carcinoma of the oral cavity: on the prognostic significance of the primary tumour site (by levels and areas).

The prognostic significance of primary tumour site in carcinomas of the oral cavity was investigated in a series of 585 cases. For the subsamples (levels and areas of oral cavity) studied, the numerical distribution of TNM categories, life tables and life table comparisons were computed. This produced the following results: Given an identical extension and analogous metastazising rate, there is no computationally demonstrable difference in prognosis between primary tumours sited at different levels and areas of the oral cavity. The exception are the T1Nx categories, for which a difference exists between precanine and retromolar sites. These results should be re-examined on the basis of a larger series.

Actuarial Analysis↗
PubMed1979

Chemical evidence for a codon-induced allosteric change in tRNALys involving the 7-methylguanosine residue 46.

[32P]TRNALys, from Escherichia coli, was modified with kethoxal, in the presence and absence of the oligonucleotide codon (A)4. The presence of the codon resulted in a faster modification rate of the tRNA at three guanine sites which were identified by a diagonal fingerprint method. A large increase in the modification rate occurred at the 7-methylguanosine residue 46 (m7G-46) in the presence of the codon: weakly enhanced modification was observed at G-15 and G-57. It is concluded that the formation of a codon-anticodon complex induces, primarily, a conformational change involving disruption of the m7G-46 from the m7G-46 . G-22 . C-13 base triple. Subsequently, the guanines of G-15 and G-57, in the D and T loops, respectively, become slightly more reactive, suggesting a weak tendency for these two interacting arms to unfold. The results are interpreted in terms of an equilibrium between two main conformers, and a third minor one; the possible significance of these conformers in protein biosynthesis, is considered.

Base Sequence↗
PubMed1979

[On the influence of thiocyanates on the delayed immune response in intact and epinephrectomised guinea pigs (author's transl)].

Daily application of 32 mg/kg sodium thiocynate from 1--11th respectively 12th--21st experimental day causes in epinephrectomised guinea pigs at the 26th experimental day an inhibition of cell-mediated immune response (sensitization was induced by intraperitoneal injection of horse serum at the 5th and 7th experimental day). The inhibition of cell-mediated immune response could be demonstrated by means of migration inhibition of spleen cells. Epinephrectomy was performed by operation procedures twice a week. Gluco- and mineralocorticoids were applied supplementary. -- Also other proved thiocyanates respectively compounds with thiocyanate groups such as potassium thiocyanate, ammonium thiocyanate and d,1-2-imino-3.4-dimethyl-5-phenyl-thiacolidinhydrothiocyanate showed the same effect. The results are only pointed out in intact animals, but distinct in epinephrectomised guinea pigs. Finally a significant weaker effect, but of the same kind was observed by potassium- and sodium iodate. Every used dose of prednisolone and cyclophosphamide suppress the migration inhibition. The influence of 2-iminothiacolidin-4-carbon acid and desoxycorticosteronacetat on the migration inhibition is different and depends on the antigen dose applied for sensitization. -- Simulated daily injections undertaken in form of stitches and application of aqua destillata are inefficacious.

Adrenal Glands↗
PubMed1979

Ultrasonic evaluation of the gallbladder in sickle cell disease.

The gallbladder is frequently diseased in sickle cell anemia. The distinction between cholecystitis and the abdominal crisis of sickle cell disease is difficult to make. Ultrasonography permits a rapid evaluation of the gallbladder in sickle cell disease.

Adult↗
PubMed1978

[Hormone dependent, functional gynecologic morphology in infancy and adolescence presented on the example of the cervix uteri].

Signs of different activities in the dynamic morphology of the epithelium and mucus of the cervix uteri are demonstrated in the female fetus, newborn, child and adolescent. Besides the morphological description of the ectropium, transitional zone, s.c. "reserve-cells", squamous cell nodes and production and secretion of mucus other investigations were done by allometry, caryometry and histochemistry. The examinations allow insight into the hormonal activities specially of the estrogenes in different periods of female life.

Adolescent↗
PubMed1978

Differentiation and aging of the rat intestinal mucosa. II. Morphological, enzyme histochemical and disc electrophoretic aspects of the aging of the small intestinal mucosa.

At different times of day (08.00, 12.00, 16.00 and 24.00) the small intestinal mucosa of four month (adult) and 30 month (senile) old rats was examined histologically, by scanning electron microscopy, autoradiography, enzyme histochemistry and disc electrophoresis. In senile rats a villous atrophy is found histologically and an irregular architecture is found in scanning electron microscopy. The changes are essentially restricted to the proximal small intestine. The enterocytes of adult and senile rats show an identical enzyme histochemical picture. In the proximal small intestine of adult and senile rats, synchronous statistically significant fluctuations of the activity of alkaline and acid phosphatase were revealed in the disc electropherograms. Likewise statistically significant are the at all times of day low enzyme activities in the intestinal mucosa of senile rats as compared to the findings in adult rats. The fall in activity of alkaline and acid phosphatase in old rats is attributed to the numerical reduction of the enterocytes which is caused by the age atrophy of the intestinal mucosa. These findings are discussed in connection with results of our own studies of proliferation kinetics and those of other authors.

Acid Phosphatase↗
PubMed1978

Ischemia and post-ischemic regeneration of the small intestinal mucosa. An enzyme-histochemical investigation.

After ligation of the vascular arcades of the upper jejunum in rats, the ischemic damage to the intestinal mucosa and its regenerative behavior after ischemia lasting 120 minutes were investigated with histological and enzyme-histochemical methods. During the ischemic injury of the jejunal mucosa, there is rejection of hydropically swollen epithelial cells into the intestinal lumen advancing from the tip to the base of the villi without a previously detectable loss of activity of the enzymes investigated. At the end of ischemia lasting 120 minutes, there is complete destruction of the villi as well as the upper portions of the crypts. After rapid re-epithelialization of the mucosal surface by a flat epithelium, reformation of villi begins already after a 24 h period of regeneration. On the third day of regeneration, the intestinal mucosa has plump villi again. Their epithelia already show the morphological characteristics of mature enterocytes. On the other hand, enzymatic maturation of the enterocytes is only concluded between the first and second week of regeneration. An altered proliferation kinetics of the crypt epithelia due to the repair process is discussed as cause of this delayed enzymatic maturation of the enterocytes relative to the morphological differentiation. Although the intestinal mucosa has a regular villous structure again after regeneration lasting 8 days, enzyme histochemical finding in the lamina propria indicate that the process of repair is only complete here in the sixth week of regeneration.

Acid Phosphatase↗