Biomedical subjects

H Scherz

Publications and source records attributed to H Scherz.

At least 19 recordsLinked to original sources

PubMed2000

Development and evaluation of a new method for the determination of the carotenoid content in selected vegetables by HPLC and HPLC-MS-MS.

Epidemologic studies have shown inverse correlation between the consumption of carotenoid-rich vegetables and the incidence of cancer. Therefore, analytical techniques for the quantitative determination of carotenoids in complex sample matrices are important. The most used method is reversed-phase (RP)-high-performance liquid chromatography (HPLC). In this study, seventeen mobile-phase systems described in the literature and six RP-HPLC columns with differences in particle size and porosity are evaluated. Derived from these results, a new mobile-phase (acetonitrile, methanol, chloroform, and n-heptane) including solvent modifiers is presented, which allows an improved and more efficient separation of carotenoids. From all columns tested, the best chromatographic parameters are found using a silica C18 column (250 x 2 mm, 5 microm, 100 A). As was found, absorbance detection at 450 nm allows the determination of the carotenoids down to the picogram range with good linearity (R2 > 0.98). For the identification and quantitation of carotenoids in complex sample matrices (containing additionally other ultraviolet-absorbing compounds), the optimized RP chromatographic system is coupled to a mass spectrometer (MS) using an atmospheric pressure ionization interface. The calibration plots show high linearity (R2 > 0.99), and the detection limit is found in the lower nanogram range. Furthermore, collision-induced dissociation in the ion source allows for the identification of carotenoids by their characteristic fragmentation pathways. In this study, a total of nine species of vegetables commonly consumed in Central Europe are analyzed for their contents of carotenoids (namely lutein, zeaxanthin, beta-cryptoxanthin, and beta-carotene) by RP-HPLC and RP-HPLC-MS-MS. It is found that good sources for lutein are spinach, kale, and broccoli, and sources for beta-carotene are broccoli, spinach, kale, carrots, and tomatoes. This new method is an improvement for the identification and quantitation of carotenoids in complex biological tissues.

Carotenoids↗

PubMed1994

Cerebrospinal fluid shunt infection secondary to Escherichia coli bacteriuria.

A 10-year-old girl with a lumbosacral myelomeningocele, managed with clean intermittent catheterization, presented with headache, vomiting, and lethargy. The cerebrospinal fluid (CSF) and urine cultures revealed Escherichia coli, documented to be the same subtype. The organisms were subtyped and the E. coli from both the urine and CSF were noted to be of the same strain. Management consisted of intravenous antibiotics and ultimate replacement of the ventriculoperitoneal shunt. Children with myelodysplasia and CSF shunts should be carefully monitored in a multidisciplinary fashion to anticipate, correctly diagnose, and treat CSF shunt infections associated with bacteriuria.

Bacteriuria↗

PubMed1992

Thin-layer electrophoresis of hydroxyethyl starches on a modified silica gel support.

The recent developed thin-layer electrophoresis on modified silanized silica gel was applied to the separation of hydroxyethyl starches (HES) and glycogen and of HES with different degrees of substitution. This method permits a rapid qualitative and semi-quantitative determination of HES in animal tissues such as liver, lung, heart and kidney after their disintegration with alkali and precipitation with ethanol.

Animals↗

PubMed1990

Thin-layer electrophoretic separation of monosaccharides, oligosaccharides and related compounds on reverse phase silica gel.

The electrophoretic mobilities of monosaccharides, oligosaccharides, sugar alcohols and sugar acids were determined in 0.3 M borate buffer, pH 10, using thin-layer electrophoresis on silanized silica gel, pretreated with octanol-1. A rapid separation of a number of sugars, occurring in foods, could be achieved. Using a 0.05-0.1 M neutral solution of barium acetate as electrolyte, thin-layer electrophoresis allowed excellent and rapid separation as well as identification of all common uronic acids which are constituents of many acidic polysaccharides.

Electrophoresis↗

PubMed1988

Characterization of proteins and fatty acid composition in Galapagos fur seal milk. Occurrence of whey and casein protein polymorphisms.

1. Milk proteins of the Galapagos fur seal (Arctocephalus galapagoensis) were separated adequately into whey and casein fractions using bovine milk analysis methods. 2. In samples from days 5-30 of lactation 40% of the total proteins were whey and 60% caseins; in mid-lactation, day 150, 25% were whey and 75% casein proteins. 3. Electrophoretic and isoelectric focusing patterns of fur seal whey protein differed widely from bovine patterns, whereas those of caseins were similar. 4. Polymorphisms of fur seal whey and casein proteins were noted and did not seem related to different stages of lactation. 5. C-16 and C-18 fatty acids contributed about 70% of fatty acids; 63% of the total acids in milk fat were unsaturated.

Animals↗

PubMed1986

Thin-layer electrophoretic behaviour of oligo- and mono-saccharides, uronic acids and polyhydroxy compounds obtained as biomass degradation products.

A recently developed thin-layer electrophoretic method has been applied to the determination of biomass degradation products comprising mono-, oligo- and polysaccharides and their derivatives as well as phenolic compounds. The separation was carried out using 0.3 M aqueous borate solution as the buffer and silanized silica gel as the support, the surface of the latter being covered with a thin film of octanol-1. For visualization of the carbohydrates, specific sulphuric acid-containing naphthoresorcinol and orcinol reagents were applied. The mobility of hydrolyzed products is determined by the number and position of their reactive sites and, to a less extent, by the size of their molecule. The good separations obtained confirm this method as an alternative to the commonly utilized chromatographic procedures.

Biodegradation, Environmental↗

PubMed1986

Endobronchial metastasis from prostate carcinoma.

Metastasis from the prostate to the lungs is common; however, endobronchial metastasis from the prostate has been reported only twice. We report a patient with endobronchial metastases from the prostate in the absence of bony metastases. Clinical and roentgenographic findings of pulmonary metastases from prostate cancer are described, and therapeutic considerations are discussed.

Adenocarcinoma↗

PubMed1984

[The analysis of polysaccharides used as food additives. VIII. Simple qualitative and semiquantitative procedures for the determination of alginates in food].

For a rapid and specific assay of alginate, the isolated polysaccharide is split by methanolic hydrochloric acid, the reaction products are separated on silica gel plates and visualized by an uronic acid specific naphthoresorcinol-hydrochloride acid reagent. With the solvent ethylacetat/tert. butanol/water (68 + 23 + 9, v/v/v) the Rf-values of the hydrolysis compounds of alginate differ distinctly from those of the other uronic acids, which are constituents of commercial polysaccharides. The method had been tested successfully on a series of different foods (e.g. propyleneglycol alginate in beer).

Alginates↗

PubMed1983

[Chemical composition of seeds from Cucumeropsis mannii Naudin and their suitability as food].

Dehulled seeds from Cucumeropsis Mannii Naudin mainly consist of lipids (40.3%) and proteins (34.5%). Carbohydrates, minerals, and water amount to 16.5, 3.7, and 5.9%, resp. From this composition a caloric value of 2 190 kJ/100 g is calculated. The major component of the oil linoleic acid (57.9%). Short-chain fatty acids are absent. All important macro and micro nutrient elements are present in sufficient amounts for human nutrition. The seeds are rich in vitamin E and in niacin (30.8 mg/100 g and 14.3 mg/100 g. resp.). Consumption of 100 g dehulled seeds covers the daily requirement of essential fatty acids, vitamin E and essential amino acids--methionine excepted. Besides starch (14.3 g/100 g) sucrose (1.14 g/100 g), raffinose (0.42 g/100 g) and stachyose (0.41 g/100 g) as well as traces of glucose and fructose are present. The proteins extracted with various solvents (H2O, 0.1 M KCl-, 0.1 mM K3PO4-, and 0.5% SDS-solution) are studied by amino acid analysis. SDS-electrophoresis and isoelectric focusing. Molecular weights of these proteins are between 5,000 and 80,000 daltons with the fraction between 20,000 and 35,000 predominating. The seeds exhibit weak inhibition of trypsin and do not inhibit alpha-chymotrypsin.

Amino Acids↗

PubMed1981

Comparison of stapled and hand-sutured gastrectomies.

We reviewed 585 Billroth II gastrectomies to compare the results of stapled and hand-sutured cases. In 385 patients who had the duodenal stump handled by conventional methods, 18 (4.7%) leaked, compared with four (2.5%) leaks in 160 patients who had the duodenal stump stapled. In 474 hand-sutured anastomoses, there were 12 complications (leaks, hemorrhage, or obstruction), whereas there were no complications in 71 stapled anastomoses. We conclude that stapling provides an expedient way of performing gastrectomies that is at least as safe if not safer than conventional hand suture.

Adolescent↗

PubMed1980

[Analytical determination of polysaccharide thickening agents for foods--a review (author's transl)].

In this report, the analytical methodology, as developed by the authors for polysaccharides, used as thickening agents in foods is reviewed and summerized. Present additive regulations increase actuality and need for this subject. The analytical methodology consists of the following steps: a) isolation of the polysaccharides from the food samples, b) purification of the polysaccharide, c) determination of the monomeric compounds by thin layer chromatography or by gas chromatography, d) separation into neutral and into acid compounds by ion exchange chromatography on DEAE-Cellulose and e) determination of the types of linkages between monomeric compounds by permethylation.

Chromatography, DEAE-Cellulose↗

PubMed1978

[Analysis of polysaccharides used as food additives. VI. Identification of mixtures of polysaccharides by methylation analysis (author's transl)].

Polysaccharide mixtures used as stabilizers having identical sugar units, but differing in their linkages can be identified with confidence by means of methylation analysis. Such mixtures are methylated with sodium hydride and methyl iodide in anhydrous dimethylsulfoxide. The methylated products are acid hydrolyzed and the resulting methyl sugars are separated and identified by thinlayer- or gaschromatography.

Chromatography, Gas↗

PubMed1976

[Analysis of polysaccharides used as food additives iv. Gaschromatographic identification and determination of neutral components in polysaccharide-hydrolysates (author's transl)].

The monosaccharides, which are obtained by hydrolytic cleavage of the polysaccharid containing stabilisators, can be separated gaschromatographically by the way of their aldonitrilacetates. After hydrolysis, the mixtures are neutralized by an anion exchanger, evaporated to dryness, converted in pyridin with hydroxylamin to the aldoximes and hereafter with acetic anhydride to the aldonitrilacetates. Dissolved in chloroform, these compounds are used for gaschromatographic separations; only one peak is obtained for each sugar. This is a great advantage to the previous methods, where the anomeric constellations lead up of five peaks for one sugar compound and for complicated sugar mixture, it therefore was difficult to evaluate their gaschromatograms.

Chromatography, Gas↗

PubMed1976

[Analysis of polysaccharides used as food additives. V. Gaschromatographic identification of hydrolysis products in uronic acids containing polysaccharides].

Alduronic acids can be found among the monomeric units of polysaccharides, which are used as stabilisators in the food industry. Gaschromatographically they cannot be separated directly by the way of their aldonitrilacetates but it is possible by the procedure described. The 1-0-methylalduronic-acidmethylesters, obtained by the methanolysis of the polysaccharides, are reduced with boronhydrid to the corresponding methyl glycosides; there are split with acid to the aldoses, which are converted in pyridine with hydroxylamine to the aldoximes and than with acetic anhydride to the aldonitrilacetates, which can be separated by gaschromatography without difficulty.

Chromatography, Gas↗

PubMed1976