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Biomedical subjects

B Evers

Publications and source records attributed to B Evers.

13 recordsLinked to original sources
PubMed1997

Specificity of amylases and cyclodextrin-glucanotransferase in reactions with 2-deoxy-maltooligosaccharides.

2-Deoxy-maltooligosaccharides of different chain length were tested as substrates for exo- and endo-amylases. Cleavage occurred with beta-amylase, yielding 2,2'-dideoxy-maltose, and with amyloglucosidase. With the alpha-amylase from Thermomonospora curvata tris-(2-deoxy)-maltotriose and the corresponding tetra- and pentasaccharides were formed. Porcine pancreatic alpha-amylase did not tolerate the deoxygenated substrate, nor were cyclization experiments with cyclodextrin-glucanotransferase (CGT) successful. In a coupling reaction with CGT, however, a series of transfer products to the acceptor 2-deoxyglucose were obtained.

Amylases↗
PubMed1997

Further syntheses employing phosphorylase.

Maltopentaose was immobilized on silica gel and used as a recyclable primer in the reaction of glycogen phosphorylase with D-glucal. An improved method to obtain 2-deoxy-alpha-D-arabino-hexopyranosyl phosphate (4) by using this catalyst as well as the specific synthesis of low molecular weight, water-soluble 2-deoxy-maltooligosaccharides (12, 13, 14 and 15) are described. Further investigations with modified phosphorylase substrates showed that mannosyl phosphate (16) can be slowly transferred to the primer maltotetraose. alpha-1,4-Mannosyl-maltotetraose (17) and its degradation product alpha-1,4-mannosyl-maltose (18) were identified.

Carbohydrate Sequence↗
PubMed1996

Unusual development of acute exertional compartment syndrome due to delayed diagnosis. A case report.

Our report describes the case of a 20 year old man who developed an acute exertional anterior tibial compartment syndrome after playing soccer for five minutes. No trauma was reported. Correct diagnosis was delayed for 18 hours, because pain was misinterpreted as resulting from acute muscular tetanic spasm induced by hyperventilation. Fasciotomy was contributed. After one year, the patient complained of early fatigue. Electromyographically the reinnervation had not yet been completed. This case illustrates the necessity for careful observation of non-trauma related acute tibial anterior pain appearing even at the beginning of strenuous exercise. It is important to recognize the possibility of a very acute onset of exertional compartment syndrome that does not subside with rest. Only early diagnosis and fasciotomy can prevent severe complications of an acute exertional compartment syndrome.

Acute Disease↗
PubMed1994

Analysis of oligosaccharides containing 2-deoxy-alpha-D-arabino-hexosyl residues by the reductive-cleavage method.

A mixture of oligosaccharides containing (1-->4)-linked 2-deoxy-alpha-D-arabino-hexosyl ("2-deoxyglucosyl") and (1-->4)-linked alpha-D-glucosyl residues (1) was analyzed by reduction, permethylation (perethylation), degradation to monomers, and GLC-MS. Degradation was performed either by hydrolysis with subsequent reduction, by methanolysis, or by reductive cleavage, always followed by acetylation. Reductive cleavage turned out to be the method of choice for the acid-labile 2-deoxy sugars. The main degradation product formed during acid hydrolysis of 2-deoxy-D-arabino-hexosyl residues yielded, after reduction and acetylation, (4R,S)-6-O-acetyl-2,3,5-trideoxyhexono-1,4-lactone (7). By methanolysis, in addition to the expected methyl glycosides, methyl 2,3,5-trideoxy-6-O-methyl-4-hexulosonate (12) is formed as a by-product. For determination of the distribution of chain lengths, the permethylated oligomers were separated by reversed-phase HPLC. For peak assignment, one isolated oligomer was investigated by FABMS and 1H NMR spectroscopy. The average degree of polymerization (dp) calculated from the HPLC chromatogram is in good agreement with the reductive-cleavage results.

Carbohydrate Conformation↗
PubMed1994

Synthesis of 2-deoxy-alpha-D-arabino-hexopyranosyl phosphate and 2-deoxy-maltooligosaccharides with phosphorylase.

A convenient one-step synthesis of 2-deoxy-alpha-D-arabino-hexopyranosyl phosphate on a millimolar scale is described by reaction of potato phosphorylase with D-glucal at equimolar phosphate concentration. Furthermore, in the presence of catalytic amounts of phosphate, a 2-deoxy-maltooligosaccharide is obtained from maltotetraose and D-glucal. The water-insoluble oligosaccharide was isolated and characterized by 1H and 13C NMR spectroscopy. An average dp of 20 was thus determined.

Carbohydrate Sequence↗
PubMed1993

Editorial.

Explore the source record for details and available documents.

Economics↗
PubMed1991

[In situ protection of the liver with Bretschneider HTK solution].

Liver resections are usually performed under occlusion of the hepatoduodenal ligament (Pringle manoeuvre) in order to limit operative blood loss. The maximal ischemic tolerance, although individually different, is generally accepted to be 60 min. Resections of centrally located tumors require precise preparation, sometimes combined with vascular reconstructions. In such cases a prolonged ischemic time is inevitable. A save prolongation of the ischemic tolerance could be useful for extensive liver resections. In an experimental study in pigs ischemic tolerance of the liver was studied under hypothermic protection with the HTK solution of Bretschneider during 2 and 3 h. Deterioration of liver function was compared with a warm ischemia during 2 h. Results showed significantly less serum transaminase activities and better hepatic blood flow (ICG test) after an ischemia under protection with the HTK solution compared to a warm ischemia during 2 h. A prolonged ischemia during 3 h under protection with the HTK solution was well tolerated. First clinical applications of hypothermic hepatic protection during resection were successful.

Animals↗
PubMed1991

[Periimplant alterations under cyclosporin A drug treatment].

One titanium implant of the Brånemark system and one Al2O2 ceramic implant each were inserted in the lower jaws of 6 Beagle dogs to evaluate the alterations of the periimplant tissues under CsA therapy. During the 3-6 months of CsA substitution hyperplastic alterations were observed as soon as after the 3rd week. These anomalies were most pronounced around the titanium implants.

Aluminum Oxide↗
PubMed1989

Enzymatic formation of nitrogen oxides from L-arginine in bovine brain cytosol.

In dialyzed bovine brain cytosol, the enzymatic formation of nitrogen oxides was directly determined. The basal formation of nitrite and nitrate was concentration-dependently enhanced by L-arginine (EC50 about 3.10(-5) M). Both the basal and L-arginine induced formations were inhibited by NG-monomethyl-L-arginine (EC50 about 2.10(-4) M). In the presence of L-arginine, a concomitant formation of citrulline was detected. L-Arginine methyl ester also served as a substrate, but neither D-arginine, D-arginine methyl ester nor N alpha-benzoyl-L-arginine ethyl ester did so. The formation of nitrite and nitrate was time-dependent, increased linearly with the protein concentration of the cytosol and was not observed when the cytosolic proteins were heat-denaturated. Exogenous NADPH (or NADP+) concentration-dependently enhanced the formation of nitrite and nitrate, whereas NADH, NAD+, FAD, Ca2+, Mg2+ and calmodulin were ineffective. These results indicate that bovine brain contains a cytosolic enzyme which uses NADPH or NADP+ as cofactors to form nitrogen oxides from both an endogenous non-dialyzable substrate and from L-arginine.

Animals↗
PubMed1987

[Use of 51-Cr2O3 and TiO2 as markers for the determination of passage rate and protein digestibility in rats].

In a tripartite experiment with five rats each the suitability of 51Cr2O3 and TiO2 as markers was tested for estimating the transit time and passage rate as well as the total protein digestibility and the proportion of endogenous nitrogen in the small intestine with very small samples. Both markers are suited for these tests because of their simple analysis, their high recovery rate (94...105% for 51Cr2O3; 98...105% for TiO2) and their quantitative excretion in faeces within 3 days. Depending on the level of crude fibre (5.1 resp. 9.4% of DM) the transit time was found to be 7...8 h for a commercial breeding feed and 5...6 h for this commercial feed +15% straw meal. After the application of a single doses, the marker excretion of 50% appeared within 10 +/- 1 h resp. 8 +/- 1 h, and after the 12th hour there were no significant differences at all. The apparent N-digestibilities estimated by the conventional or the 51Cr2O3 resp. TiO2 indicator method did not show any differences. The proportion of endogenous nitrogen at the end of the small intestine calculated on the basis of the indicator dilution method was 83 +/- 11% for 51Cr2O3 and 83 +/- 12% for TiO2.

Animals↗
PubMed1979

[Studies of differences in protein accretion in mice by means of cell-free protein synthesis systems].

A comparison of the stimulating activity of the muscle cell sap fraction of mice of the 0th, 4th and 6th generations selected according to the protein content in their carcasses in the cell-free ribosomal and polysomal protein synthesis systems showed that both systems are applicable to detect differences in accretion of protein. These differences ar much more distinct in the cell-free polysomal system than in the ribosomal poly(U) system.

Animals↗