Search PubMed⌕ Search

Biomedical subjects

R Schubert

Publications and source records attributed to R Schubert.

At least 127 records · Page 7Linked to original sources
PubMed1989

The legumin gene family: structure and evolutionary implications of Vicia faba B-type genes and pseudogenes.

We have characterized several Vicia faba genes encoding methionine residue-free group B subunits of the 11S or legumin storage proteins. The respective gene subfamily consists of 10 to 15 members, six of them having been studied by DNA sequence analysis. Four functional genes (LeB2, LeB4, LeB6, LeB7) are highly homologous in their coding region and 0.3 kb of their 3' flanking sequences. On the other hand, two pseudogenes (psi LeB1, psi LeB5) have accumulated a large number of mutations including an identical 0.7 kb internal deletion; they are both flanked by a repetitive element. Analysis of sequence changes show that transitions are nearly double as frequent as transversions. CpG is the most infrequent dinucleotide whereas TpA is significantly underrepresented in exon sequences. End points of deletions are correlated with short direct repeats and preferentially found in the two introns. Our studies indicate that the Vicia faba legumin B gene subfamily contains a group of expressed, highly homologous genes as well as more diverged pseudogenes.

Amino Acid Sequence↗
PubMed1989

[Ruminal 15N-straw degradation in sacco and the in vivo digestibility of 15N from straw in the sheep and pony].

The nylon-bag method was applied for determination of the rumen degradation of dry matter and nitrogen of 15N-labelled wheat straw. For the experiment 4 wethers fitted with a rumen cannula were used. The bags containing 15N straw were introduced into the rumen and withdrawn 3, 6 or 12 h after incubation. In a second experiment the apparent 15N-digestibility of the same straw was determined in wether and pony. The dry matter disappearance varied between 6 and 23%. For 15N-labelled straw the disappearance of 15N was higher than that of total N. 12 h after incubation 71% of 15N and only 25% of total N were disappeared. It was calculated that after incubation rumen microbial-N in the nylon bag increased from 31% (3 h) to 45% (6 h) and 61% (12 h) resp. The apparent 15N digestibility amounted 53 +/- 2% for wethers and 51 +/- 2% for ponies.

Animal Feed↗
PubMed1989

[On the importance of nonparametric approaches for a comparison of income inequality in different countries].

"A comparison of income inequality in different countries can be made on the basis of parametric or nonparametric approaches. Using nonparametric instead of parametric approaches may raise the validity of such comparisons in some respects. However, new sources of validity reduction may be linked with nonparametric approaches. An important source of validity reduction is the influence of the type of data grouping on inequality measures. Therefore, nonparametric approaches are not strictly preferable to parametric approaches when comparing income inequality in different countries." (SUMMARY IN ENG)

Economics↗
PubMed1989

The use of arginine brilliantgreen glucose peptone broth (ABGP medium) as a primary culture medium for Pseudomonas aeruginosa.

A new medium is described for the isolation of P. aeruginosa organisms which have been damaged by chlorination. This medium utilises the fact that with arginine. P. aeruginosa produces a strongly alkaline reaction resulting in an easily identified colour change from gray-green to blue-violet. The indicators used for this purpose are bromothymol blue and cresol red. The medium may be used with either the membrane filter or the liquid enrichment technique. Incubation is at 37 degrees C for 24 or 48 h.

Anti-Infective Agents, Local↗
PubMed1989

[A method for the standardized in vitro testing of biomaterials with bacterial cultures].

The preclinical investigation of potential biomaterials requires a comprehensive profile of biological parameters. In the present paper a new in vitro test will be described which allows a standardized testing of the effect of biomaterials on the proliferation of bacteria. For this test eluates of solid materials, granulates or powders of potential biomaterials were prepared. These eluates were mixed a bacterial culture containing a definite number of microbes and incubated for 4-20 hours at 37 degrees C. The effect on bacterial growth was determined photometrically.

Biocompatible Materials↗
PubMed1989

Activation and blocking effects of divalent cations on the calcium-dependent potassium channel of high conductance.

Using the patch-clamp technique the action of internal barium- and magnesium-ions on the calcium-dependent potassium channel in the membrane of vascular smooth muscle cells from the media layer of the human aorta was studied. Under symmetrical potassium conditions in excised inside-out patches bathed in the standard solution containing EGTA, the addition of barium as well as magnesium led to a concentration-dependent shift of the activation-curves to negative values of the membrane potential compared with the control, a block of single channel activity by barium, whereas no inhibitory effects by magnesium were registered. Thus, these results suggest that the process of channel activation of the calcium-dependent potassium channel of high conductance depends not merely on calcium but also on other divalent earthalkali ions.

Barium↗
PubMed1988

Structural changes in vesicle membranes and mixed micelles of various lipid compositions after binding of different bile salts.

Binding equilibria of common bile salts (BS) and different mixtures of membrane lipids were correlated with BS-induced structural changes of large unilamellar vesicles, with transition of vesicles to mixed micelles (MM), and with successive transformations of MM. At very low BS concentrations, in the outer vesicle monolayer definite BS/lipid aggregates are formed, the size and BS binding strength of which depend on the BS and lipid species involved. At increasing BS concentrations, binding to the membranes is hampered, and above a critical BS content, membrane stress due to asymmetric BS binding leads to formation of transient membrane holes, as shown by inulin release from the vesicles. Independent of the BS and lipid species, membrane solubilization starts at a ratio r = 0.3 of bound BS/lipid. Increasing phosphatidylserine, phosphatidylethanolamine, and cholesterol contents stabilize the lecithin membrane against BS to different degrees and in different ways, whereas the destabilization by sphingomyelin is probably due to the enhancement of the membrane gel-liquid transition temperature. Conjugation of the BS with glycine or taurine has a modulating effect on membrane hole formation, rather than on lipid solubilization. Diphenylhexatriene fluorescence anisotropy indicates a BS-induced drop of the internal membrane order and its restoration during membrane solubilization. At higher concentrations ursodeoxycholate induces additional condensation, whereas the other BS cause internal disorder in the MM. Above ratios r of approximately 8:1, we found a release of BS from these MM and suggest a rodlike structure for them. The results were discussed with respect to BS/membrane interactions during lipid excretion from the liver cell.

Bile Acids and Salts↗
PubMed1988

[The glutamic acid decarboxylase disc test. An approach for the simplification and speeding up of E. coli detection].

Although E. coli is certainly one of the best known and most widely examined bacterial species only few of their characters and properties were found suitable for the distinction of this species from other species especially from the coliform organisms. One of these rare characters is l-glutamic acid decarboxylase. The demonstration of the action of this enzyme, however, has hitherto been difficult and time consuming. A micro-method is described which permits the demonstration of l-glutamic acid decarboxylase--the glutamic acid decarboxylase disc test (gd-disc-test). The conditions and procedures required are described in detail. The validation of this test was done demonstrating in presence of gamma-aminobutyric acid by paper chromatography.

Chromatography, Paper↗
PubMed1988

[The problem of degradation and histocompatibility of bioactive ceramics in soft tissues. 1. Studies of the degradation of bioactive ceramics in soft tissues].

Following implantation of bioactive ceramics both into the bone and the subcutis the implantat surface changed to be relative rich in Ca and absolutely poor in P as indicated by means of electron microprobe. The implants located into the subcutis however, resulted in a more distinctive alteration of those surfaces. This process caused by the interaction between bioactive vitrified ceramics and the connective tissue can be prevented by coating the appropriate parts of the implants with Dentalceramics. A 10 micron to 15 micron layer may to be sufficient.

Animals↗
PubMed1988

[The problem of degradation and histocompatibility of bioactive ceramics in soft tissues. 2. Descriptive and morphometric evaluation of uncoated and coated bioactive ceramics].

After a 180 day lasting period of observation a persistent chronical inflammation occurred in the implants surrounding tissue of rats implanted with simple sintered biovitroceramics, where as the same material, coated with dental ceramic did not result in a comparable tissue reaction. After application of these coated implants we obtained a significant diminished formation of the periimplant connective tissue capsule. Inactivation of surfaces, being into contact with soft tissue, mentioned above, could be an economical, easy handling method.

Animals↗
PubMed1987

[Internal migration in developing countries: rationality of rural-urban migration].

"In many developing countries there is a positive and nondecreasing rural-urban net migration. As a rule, making migration decisions jointly is advantageous for individual potential migrants and their families. Rationality of migration decisions depends on the specific character of the constituents of the basic decision model. In most cases, individual or family rationality of migration does not coincide with collective rationality. Trying to bring the two together requires trying to improve the coordinative function of main economic variables and trying to improve the decision makers' information." (SUMMARY IN ENG)

Behavior↗
PubMed1987

[Surface analysis of Bio-Sinter ceramic specimens using Rutherford backscattering spectrometry following subcutaneous implantation].

The formation of a calcium and phosphorous containing surface-layer is one of the essential suppositions of bioactive materials for the replace of bone. In the submitted study on sintered Bio-Vitro-ceramic specimens, which where explanted from the subcutaneous tissues of rats after 20, 40, 90 and 180 days, a relative increase of calcium content, and an absolute increase of phosphorous content of the direct surface of the specimens (approximately 0.01 micron) could be demonstrated. In contrast to not implanted specimens the values of silicat were 90% lower. After 180 days of implantation the distribution of elements at the surface of all types of sintered specimens had been stabilized 1.6 (Ap40KS15), 7.1 (Ap40KS30), 2.3 (Ap40SV).

Animals↗
PubMed1987

[Suitability of thermal selection for the primary culture of Pseudomonas aeruginosa].

It could be shown by quantitative methods that growing P. aeruginosa suspensions at 42 degrees C without any loss is possible only in a medium without any inhibitory additives--when suspensions of unimpaired organisms are used. The addition of inhibitors e.g. malachite green without influence to the growth rate of P. aeruginosa at 37 degrees C leads to a marked reduction of growth at temperatures only slightly higher e.g. 38 degrees C. This can also be observed when poor media like Drake's medium 10 are used. The method of thermic selection was the most inappropriate for the culture of P. aeruginosa organisms impaired by chlorine. Germs which showed good growth at 37 degrees C could be grown only at a very reduced rate at 42 degrees C even though a rich medium free of inhibitory additives was used. Thermic selection is not suited to the cultivation of P. aeruginosa from samples of water which as a rule is chlorinated e.g. swimming pool water.

Bacteriological Techniques↗
PubMed1987

Comparative investigations of the reoccluded distal anastomosis, the spontaneous atherosclerotic plaque and the normal intima of the human femoral artery.

The reocclusion of the distal anastomosis in grafts of the femoral artery frequently occurs, but there is no exact information about its character. A comparative study of such reocclusions, including the nature of the spontaneous atherosclerotic plaque and of the normal intima of the human femoral artery has been performed by light-microscopic, immunomorphological and biochemical methods. Local thickening in the region of the distal anastomosis was found to resemble the atherosclerotic plaque in structure, location of several components of the extracellular matrix and in the cellular composition. These facts allow the conclusion, that progressive atherosclerosis is the cause of the reocclusion of the distal anastomosis.

Adult↗
PubMed1987

[Assessment of the interface reaction of endosseous implanted bio-sinterceramics by electron probe microanalysis].

The electron ray microanalysis (ESMA) showed an intimate bone-implant-compound already 4 weeks postoperatively. This compound was detectable in all sinter variants after 78 weeks. An area with changed material contrast was prepared on the surface of the implant with an extent of 45-55 micron until the 24th week and over 100 micron after 78 weeks. A surface stratum relatively rich in calcium and absolutely rich in phosphorus was formed in the immediate contact to the regenerated bone opposite to the implant nucleolus. This stratum had an approximate consistent extent of 20-35 micron from the 12th week. The relative intensity of the stratum rich in calcium and phosphorus corresponded to that of the bone around the implant. The stabilization of the reactive surface stratum can become assumed by that.

Animals↗
PubMed1986

Structural changes in membranes of large unilamellar vesicles after binding of sodium cholate.

The interaction of the bile salt cholate with unilamellar vesicles was studied. At low cholate content, equilibrium binding measurements with egg yolk lecithin membranes suggest that cholate binds to the outer vesicle leaflet. At increasing concentrations, further bile salt binding to the membrane is hampered. Before the onset of membrane solubilization, diphenylhexatriene fluorescence anisotropy decreases to a shallow minimum. It then increases to the initial value in the cholate concentration range of membrane solubilization. At still higher cholate concentrations, a drop in fluorescence anisotropy indicates the transformation of mixed disk micelles into spherical micelles. Perturbation of the vesicle membranes at molar ratios of bound cholate/lecithin exceeding 0.15 leads to a transient release of oligosaccharides from intravesicular space. The cholate concentrations required to induce the release depend on the size of the entrapped sugars. Cholesterol stabilizes the membrane, whereas, in spite of enhanced membrane order, sphingomyelin destabilizes the membrane against cholate. Freeze-fracture electron microscopy and phosphorus-31 nuclear magnetic resonance (31P NMR) also reflect a change in membrane structure at maximal cholate binding to the vesicles. In 31P NMR spectra, superimposed on the anisotropic line typically found in phospholipid bilayers, an isotropic peak was found. This signal is most probably due to the formation of smaller vesicles after addition of cholate. The results were discussed with respect to bile salt/membrane interactions in the liver cell. It is concluded that vesicular bile salt transport in the cytoplasm is unlikely and that cholate binding is restricted to the outer leaflet of the canalicular part of the plasma membrane.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1986

Determination of prostaglandin E2, prostaglandin F2 alpha and 6-oxo-prostaglandin F1 alpha in urine by gas chromatography/mass spectrometry and gas chromatography/tandem mass spectrometry: a comparison.

Electron impact fragmentation of methyl ester/methyloxime/trimethylsilyl ether derivatives of prostaglandin E2 and 6-oxo-prostaglandin F1 alpha and the methyl ester/trimethylsilyl ether derivative of prostaglandin F2 alpha is followed by argon collision-activated dissociation in a triple quadrupole mass spectrometer. Daughter ion chromatograms of prostaglandin derivatives show an enormous increase of selectivity compared to the multiple ion detection chromatograms of the same samples in single quadrupole mode.

6-Ketoprostaglandin F1 alpha↗