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Biomedical subjects

G Reuter

Publications and source records attributed to G Reuter.

At least 145 records · Page 8Linked to original sources
PubMed1987

[Anaerobic spore formers in commercial spices and ingredients for infant food].

Anaerobic spore-formers can cause food intoxication. Clostridium (Cl.) perfringens type-A strains are mainly involved. In addition to the original contamination of food, e.g., meat or milk, ingredients such as spices or meat extracts are the main source and low numbers of clostridia are present (i.e., up to 10(2) cells/g). At present, information about the quantitative ecology of clostridia is incomplete; therefore 115 commercial food products were investigated (spices: n = 70, meat extracts: n = 15, instant foods: n = 30). For the detection of low numbers of clostridia (less than 10(3)/g), the most probable number (MPN) technique was used. For the detection of higher numbers (greater than 10(3)/g) a cultivation method in solid media was developed. The mesophilic sulphite-reducing clostridia spores were detected by the pour-plating method with overlayer. Twenty-one of the 70 commercial spices, 7 of the 30 specimen of instant food and 12 of the 15 meat extracts were clostridia-positive. The low counts ranged between 3 X 10(0) and 10(3) cells/g, in most cases (2/3) in the range 10(1)/10(2)/g. Only in 6 cases were more than 10(3) clostridia/g detected. Most of those isolated were identified as Cl. perfringens (46 of 73 isolates). Only in meat extracts did clostridia species other than Cl. perfringens strains predominate. Three of the 23 Cl. perfringens strains proved to be heat-resistant. A hydrated meat extract originally contaminated with low numbers was tested in a pilot study for the enrichment of clostridia. This extract showed an increase of up to 10(7) cells/ml after a 24-h incubation period.(ABSTRACT TRUNCATED AT 250 WORDS)

Clostridium perfringens↗
PubMed1987

A stage-specific sialoglycoprotein in encysting cells of Entamoeba invadens.

A novel sialoglycoprotein with an apparent molecular mass of approximately 250 kDa was detected on the surface of cysts of Entamoeba invadens. Sialic acid was identified in this glycoprotein by gas chromatography after methanolysis; N-acetyl- and N-glycolyl neuraminic acid were identified by thin layer chromatography in hydrolysates of partially purified preparations of the 250 kDa glycoprotein as well as in whole cysts. The sialoglycoprotein is stage-specific and could be detected by binding of wheat germ agglutinin and a specific monoclonal antibody (JAM3) only to precysts and mature cysts but not to trophozoites. A 250 kDa protein could be metabolically labeled with [35S]methionine. This, together with the absence of such a glycoprotein in the encystation medium, suggests that the 250 kDa sialoglycoprotein is not an adsorbed serum glycoprotein. Indirect evidence suggests that the parasite may utilize serum components as a source for sialic acid.

Animals↗
PubMed1987

N-acetyl-9-O-acetylneuraminic acid, the receptor determinant for influenza C virus, is a differentiation marker on chicken erythrocytes.

Erythrocytes from chicken of different age were analysed for their agglutinability by influenza C virus, which has been shown recently to use N-acetyl-9-O-acetylneuraminic acid as a high-affinity receptor determinant for the attachment to cells. Only with birds not younger than six days complete agglutination of the erythrocytes was observed. The hemagglutination titer which was initially low reached its maximum value at the age of about 20 days. Sialic acid was isolated from erythrocytes, purified and analysed by colorimetry, thin-layer chromatography, high-performance liquid chromatography, and gas-liquid chromatography-mass spectrometry. The sialic acid content of erythrocytes from one-day old and adult chicken was 21 micrograms and 18 micrograms sialic acid/ml packed erythrocytes, respectively. While N-acetylneuraminic acid was the major type of sialic acid on erythrocytes from both one-day old and adult chicken, N-acetyl-9-O-acetylneuraminic acid was only detected on red blood cells from adult animals accounting for 30-40% of total sialic acid. These results indicate that N-acetyl-9-O-acetylneuraminic acid, in addition to serving as a receptor determinant for influenza C virus, represents a developmental marker on chicken erythrocytes.

Animals↗
PubMed1986

Comparison of electron and chemical ionization mass spectrometry of sialic acids.

Sialic acids were analyzed as per-O-trimethylsilylated compounds by gas-liquid chromatography/mass spectrometry either on electron or chemical ionization by isobutane. Electron ionization mass spectra of these derivatives are very similar to those of the corresponding methyl esters described earlier whereas chemical ionization mass spectra are characterized in the high mass range by loss of the C-2 and the C-4 substituents from the M + 1 ion. Together with other fragment ions the seven different sialic acids analyzed could be clearly identified.

Esters↗
PubMed1986

Sialoglycoproteins and sialic acids of Plasmodium knowlesi schizont-infected erythrocytes and normal rhesus monkey erythrocytes.

The effects of malaria infection on RBC sialic acids and sialoglycoproteins were studied with asexual blood-stage infections of Plasmodium knowlesi in rhesus monkeys. Glycoprotein radio-isotope labelling methods were used to compare the sialoglycoproteins of normal RBC and P. knowlesi schizont-infected RBC (SI-RBC). Tritiation of glycoproteins from SI-RBC with the standard sialidase + galactose oxidase/NaB3H4 method or standard periodate/NaB3H4 method was significantly decreased when compared to normal RBC. However, tritium uptake into glycoproteins was normal when SI-RBC were treated with 5-fold higher concentrations of both enzymes in the first labelling method, or with a 5-fold increase in the molar ratio of periodate to sialic acid in the second method. The mobility of tritiated host cell glycoproteins on SDS-polyacrylamide gels was identical for SI-RBC and normal RBC. New bands, possibly glycoproteins, of 230, 160, 90, 52, and 30 kDa were detected after labelling SI-RBC by the modified periodate/NaB3H4 method. Sialic acid analysis of normal rhesus monkey RBC (62 micrograms/10(10) RBC) revealed that 46% of the total sialic acid was N-glycolylneuraminic acid, 33% was N-acetyl-9-O-acetylneuraminic acid, and the remainder N-acetylneuraminic acid. SI-RBC collected either directly from infected monkeys or after in vitro culture of ring-infected RBC in horse serum, had increased total sialic acid (126 or 115 micrograms/10(10) RBC, respectively). The sialic acid content of infected RBC must increase during parasite development since RBC infected with ring-stage P. knowlesi had the same content as normal RBC. There was no significant difference in the ratio of the three sialic acids of SI-RBC and normal RBC. In contrast, the uninfected RBC from infected blood of different monkeys showed marked variation in sialic acid composition and generally had a lower sialic acid content than normal RBC.

Animals↗
PubMed1986

[Hygiene of meat production and processing].

Meat becomes unavoidably contaminated already at slaughtering. During storage and processing this contamination is increasing in a considerable degree. Cooling immediately and continuously enables a psychrotrophic saprophytic microflora to propagate. This will provoke characteristic spoilage after a longer period of storage or at interruption of the cooling chain. A limitation of total counts from the early beginning of meat processing increases stability of meat considerably. Potential pathogenic or toxinogenic microorganisms may occur, too. Their origin has to be seen at the living animals and at the meat handlers. These microorganisms may not be allowed a competitive growth within a comprehensive psychrotrophic microflora normally. On the other hand they may get hygienic importance as resistant parts to processing steps or as recontaminants after elimination of accompanying microflora. A good manufacturing practice must be directed by limiting growth criteria for microflora components. These are lower limits of growth temperature, water activity, pH-value or anaerobic condition after packing. A good manufacturing practice may be achieved considering the HACCP-concept: Meat and meat products must be defined as risk carriers according to animal and product specialties. The numerous microflora habitats have to be known very well. Generally the risk factors and especially the critical control points in each production area have to be explained. An effective control during process stages and/or of the final products must be applied. The determination of the total count or of the count of Enterobacteriaceae as indicator organisms may be suitable at the microbiological process control. Index microorganisms may be used at special final products. The practice of processing meat and meat products may be optimized considerably. The most important aspects concerning the questions mentioned before are listed in this paper.

Animals↗
PubMed1986

[Local treatment of thermal injuries in children. Results of a multicenter study].

The study described in this paper helped to establish the present position in locally delimited treatment of children for thermic injuries. 25 hospitals or other medical institutions were involved in the inquiry programme, including 16 departments of paediatric surgery and nine departments of general surgery. Studies were conducted also into 2 outpatient departments. The programme was centrally evaluated on the basis of 15 questions distributed, in the first place, in a questionnaire. Locally delimited treatment of cases of different severities was on the list together with an analysis of open and closed wound treatment and indications for surgery to cope with injuries of greater severity. Answers were sought to questions of burn blister treatment, and reference was made to surgical removal of necrotic foci as well as to advantages implied in two-session approach to post-necrectomy cases. A critical analysis is made of fractionated necrectomy. The important of synthetic skin substitutes is underlined. Locally delimited surgical therapy is associated with aspects relating to suture fixation, scarification, and change of dressing. Benefits and drawbacks are analysed. An evaluation was made of methods for after-treatment of cured burns and of celoid treatment.

Administration, Topical↗
PubMed1985

Structural parameters and natural occurrence of 2-deoxy-2,3-didehydro-N-glycoloylneuraminic acid.

2-Deoxy-2,3-didehydro-N-glycoloylneuraminic acid has been found to occur in porcine, bovine and equine submandibular glands as well as in the urine of pig, horse and rat. This novel, unsaturated sialic acid was isolated by gel filtration and ion-exchange chromatography. Final purification was achieved by column chromatography or by preparative thin-layer chromatography on cellulose. The structural analysis was performed by combined capillary gas-liquid chromatography/mass spectrometry. The various data were compared with those from synthetic 2-deoxy-2,3-didehydro-N-glycoloylneuraminic acid. Besides of the unsaturated N-glycoloylated sialic acid, also the corresponding N-acetylated derivative was present in the materials analyzed. The inhibitory effect of 2-deoxy-2,3-didehydro-N-glycoloylneuraminic acid on Vibrio cholerae sialidase using N-acetylneuraminyl-(alpha 2----3)-lactose as substrate is slightly higher (50% inhibition at 10 microM) when compared with 2-deoxy-2,3-didehydro-N-acetylneuraminic acid (50% inhibition at 15 microM).

Animals↗
PubMed1985

Specificity of two different purified acylcarnitine hydrolases from rat liver, their identity with other carboxylesterases, and their possible function.

One of the previously described five purified monoglyceride-cleaving carboxylesterases from rat liver microsomes proved to be a carnitine ester hydrolase. This esterase, with an isoelectric point of 5.2, is most active with medium-chain acyl-L-carnitines (C12-C14). The esterase is also remarkably active with 1,3-diglycerides, especially 1,3-dioctanoylglycerol, that are hydrolyzed faster than the corresponding 1-monoglycerides and triglycerides. Only one of the other four purified carboxylesterases has moderate acylcarnitine-hydrolyzing activity. An altered procedure for the separation of the two microsomal acylcarnitine-cleaving enzymes is described. Both enzymes hydrolyze carnitine esters optimally at pH 8 and both are inactive with acetylcarnitine, palmitoyl-CoA, and butyrylthiocholine. The possible natural functions of the hydrolases are discussed. Besides their detoxifying action on natural membrane-lysing detergents (like carnitine esters and lysophospholipids), these enzymes could be involved in the transport of carnitine out of the liver.

Acetylcarnitine↗
PubMed1985

Detection of two ornithine carbamoyltransferases in a phaseolotoxin-producing strain Pseudomonas syringae pv. phaseolicola.

The phaseolotoxin-producing Pseudomonas syringae pv. phaseolicola strain 1321 contains two ornithine carbamoyltransferases which differ in resistance to phaseolotoxin. Whereas ornithine carbamoyltransferase 1 (OCT 1) is inhibited at low concentrations of phaseolotoxin, ornithine carbamoyltransferase 2 (OCT 2) is insensitive to phaseolotoxin. The activity of the insensitive enzyme is correlated with the amount of toxin formed.

Exotoxins↗
PubMed1985

Analysis of gangliosides using fast atom bombardment mass spectrometry.

The native gangliosides GM3, GM1, Fuc-GM1, GD1a, GD1b, Fuc-GD1b, GT1b and GQ1b were analysed by fast atom bombardment mass spectrometry (FAB-MS) in the negative ion mode in a matrix of thioglycerol. After permethylation the same gangliosides were analysed by electron impact (EI) and FAB-MS in the positive ion mode. The negative ion mass spectra furnished information on the molecular weight, the ceramide moiety and the sequence of carbohydrate residues. The sites of attachment and the number of sialic acids present could be deduced directly from the pattern of sequence ions. After addition of sodium acetate positive ion FAB-spectra of the permethylated samples show intense pseudomolecular ions M + Na, that provide evidence on the homogeneity of the samples. In addition, the ceramide part, the oligosaccharide moiety obtained after cleavage of the glycosidic bond of the hexosamine residue, the whole carbohydrate chain and the sialic acids are represented by specific fragment ions. With EI-MS further information can be obtained on the sphingosine and fatty acid components of the ceramide residue. The data show, that the combination of soft ionization mass spectrometry with classical EI-MS gives valuable information on the structure and homogeneity of gangliosides. The method is also applicable to the structural elucidation or quantitation of more complex gangliosides or glycolipid mixtures using only micrograms of material.

Animals↗
PubMed1985

Isolation and characterization of gangliosides from pig lymphocytes.

Two major gangliosides from pig spleen lymphocytes, accounting for 57% of the total lipid-bound sialic acids, were isolated and purified to homogeneity by column chromatography on DEAE-Sephadex and silica gel. They were identified as GM3 (II3Neu5GcLacCer), and GD3 (II3(Neu5Gc)2LacCer), by thin-layer chromatography in comparison with standards and by analysis of the constituent sugars. The major fatty acids of these gangliosides were stearic acid and myristic acid, respectively. In addition to these gangliosides, GD2 and bands comigrating on thin-layer chromatography with authentic GM2, GM1, GD1a and GD1b were found. These compounds also occur in pig peripheral blood lymphocytes, where, however, GD3 represents about 70% of the total lipid-bound sialic acid.

Animals↗
PubMed1985

Influence of palmitate and oleate on the binding of warfarin to human serum albumin: stopped-flow studies.

The rate of transition from an unstable to a stable complex and the dependence of this on the number of fatty acid ligands present was determined for the binding of warfarin on human serum albumin. When oleate or palmitate was added in amounts up to 2:1 excess to human serum albumin solutions the measured rate constant for the transition (k2) was increased in comparison with fatty acid free albumin. When the fatty acid concentration is further increased, k2 decreases. When the fatty acid level is 2 to 3 mol per mol albumin, the affinity constant (KA) is higher than for fatty acid free solutions. With higher ratios the value for KA is reduced. According to the observed changes in kinetic parameters, the binding of warfarin is apparently affected allosterically. A reduced plasma protein binding of coumarins should be expected when fatty acid levels are raised over a prolonged period.

Humans↗