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B Shaikh

Publications and source records attributed to B Shaikh.

34 records · Page 2Linked to original sources
PubMed1980

Detection of urinary metabolites of 2-acetylaminofluorene by cultured hamster embryo cells and high performance liquid chromatography.

Urine was collected from Sprague-Dawley rats injected intraperitoneally with a suspension of 2-acetylaminofluorene (AAF) or with an inert suspension vehicle. Morphological transformation was observed in clonal cultures of secondary passage hamster embryo cells (HEC) after the addition of AAF-treated rat urine or concentrated urine extracts prepared by incubating the urine with beta-glucuronidase. No morphological alteration was observed in cultures treated with urine (or urine extracts) from rats injected with the suspension vehicle alone. The presence of N-hydroxy- and ring-hydroxylated metabolites of AAF in the AAF-treated concentrated urine extract was confirmed by high-performance liquid chromatography (HPLC).

2-Acetylaminofluorene↗
PubMed1979

Characterization of methanol extraction residue (MER) from Bacillus Calmette-Guérin (BCG).

Analysis of methanol extraction residue (MER) from Bacillus Calmette-Guerin (BCG) was carried out to determine some specific chemical compositional characteristics. Samples of MER were found to contain approximately 40% protein and/or peptide, 3% soluble lipids, 17% bound lipids, 8% elemental nitrogen, and less than 2% mycolic acids. Amino acid analysis showed the presence of alanine, glycine and glutamic acid as the major amino acids. The data are reported in terms of the range found for each constituent over the samples analyzed. Somewhat consistent results were obtained between different MER preparations, but notable compositional variations were observed in samples of MER suspensions.

Amino Acids↗
PubMed1977

Determination of N1-methylnicotinamide in urine by high-pressure liquid chromatography.

This paper reports a precise method that is shorter than previously reported methods for the quantitative determination of N1-methylnicotinamide (MNA) in urine. The method employs a single column chromatographic isolation step, followed by high-pressure liquid chromatographic (HPLC) analysis. Potential interfering substances present in urine are removed during the column chromatography step. The combined MNA fractions eluted from this column were collected and concentrated for quantitative assay of MNA by HPLC. HPLC analysis was effected in less than 15 min using a strong cation- exchange column eluted with 0.25 M ammonium dihydrogen phosphate (pH 4.3). Linearity of MNA detection by HPLC at 254 nm extended below 20 ng, with an average recovery of 101% for 150, 250 and 500 microgram MNA added to 5 ml or urine.

Chromatography, High Pressure Liquid↗
PubMed1977

High performance liquid chromatographic analysis of supplemental vitamin E in feed.

Supplemental vitamin E is extracted from feed in one step with methanol and analyzed by reverse phase partition chromatography in less than 10 min, using isocratic elution with either methanol or water-methanol as the mobile phase. Detection response (as measured by peak area) was linear between 0.5 and 3.0 mug, and the coefficients of variation for retention time and peak height on replicate analyses of the standard sample were 0.8 and 2.3%, respectively.

Animal Feed↗
PubMed1970

Isolation of leucogenenol from bovine and human liver.

A compound has been isolated from both bovine and human liver that on intravenous or intraperitoneal injection into animals induces in 4-12h an increase in the number of peripheral neutrophils, and in 12-24h an increase in the number of peripheral lymphocytes. At 24h after injection there is also a two- to three-fold increase in the relative number of myeloblasts in the bone marrow. The procedure for isolation and the physical and chemical properties identify the compound as leucogenenol, isolated from the metabolic products of Penicillium gilmanii by Rice (1966).

Animals↗
PubMedDate not supplied

Application of microbial receptor assay to quantitation of residues of spectinomycin in bovine milk and comparison with liquid chromatographic analysis.

Spectinomycin-contaminated bovine milk samples were assayed by liquid chromatographic (LC) and microbial receptor methods. LC involved a newly developed analytical method to quantitate the concentration of spectinomycin in the contaminated milk samples. The receptor assay used reagents and the reaction system used for the Charm II spectinomycin assay. Three standard curves (selected range, full range, and second-order polynomial) were plotted for the receptor assay and used to quantitate spectinomycin in contaminated milk samples. The levels of spectinomycin obtained by the receptor assay, using only the standard curve in the selected range, were comparable to the results obtained by LC analysis.

Animals↗
PubMedDate not supplied

Determination of neomycin in animal tissues, using ion-pair liquid chromatography with fluorometric detection.

A liquid chromatographic (LC) method is described for the determination of neomycin in animal tissues. Tissues are homogenized in 0.2M potassium phosphate buffer (pH 8.0); the homogenate is centrifuged, and the supernate is heated to precipitate the protein. The heat-deproteinated extract is acidified to pH 3.5-4 and directly analyzed by LC. The LC method consists of an ion-pairing mobile phase, a reverse phase ODS column, post-column derivatization with o-phthalaldehyde reagent, and fluorometric detection. The LC method uses paromomycin as an internal standard, and separates neomycin from streptomycin or dihydrostreptomycin because they have different retention times. The LC column separates neomycin in 25 min; the detection limit is about 3.5 ng neomycin. The overall recovery of neomycin from kidney tissues spiked at 1-30 ppm was 96% with a 9.0% coefficient of variation. The method was also applied to muscle tissue.

Aminoglycosides↗
PubMedDate not supplied

Overview of physical-chemical methods for determining aminoglycoside antibiotics in tissues and fluids of food-producing animals.

A survey of literature is presented dealing with physical-chemical methods for the detection and quantitation of aminoglycoside antibiotics (gentamicin, streptomycin, dihydrostreptomycin, and neomycin) that are used in food-producing animals. Recent developments in cleanup and determinative procedures, particularly liquid chromatography, for these compounds in fluids and tissues are emphasized. Little research has been done on residues in tissues compared with other biological matrices. This review also covers the chemistry, general characteristics, tolerances, and withdrawal times for the approved uses of these antibiotics in animals that are used for food.

Aminoglycosides↗
PubMedDate not supplied

Improved liquid chromatographic determination of neomycin B in bovine kidney.

An improved liquid chromatographic (LC) method was developed for the determination of neomycin B in bovine kidney tissue. The tissue is homogenized twice in phosphate buffer; homogenate is centrifuged, and the supernatant is deproteinated by heat. The extract is acidified and mixed with ion-pair concentrate, and neomycin B is determined by an LC system consisting of an ion-pairing mobile phase, a reversed-phase ODS column, postcolumn derivatization with o-phthalaldehyde reagent, and fluorometric detection. Average recoveries of neomycin B from kidney tissues spiked at 3, 6, and 12 ppm were 103, 99, and 104%, with 9.7, 7.9, and 3.7% intralaboratory coefficients of variation, respectively, using a standard curve prepared in buffer. The method was used to determine neomycin B in kidney tissue obtained from a calf killed 14 days after intramuscular dosing with neomycin (5 mg/lb). The tissue was found to contain about 3 ppm neomycin B. The LC conditions were also used to assay control samples of muscle, liver, milk, plasma, and urine. No interfering peaks were noted at the elution position of neomycin B.

Animals↗