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Biomedical subjects

Joseph Sherma

Publications and source records attributed to Joseph Sherma.

6 recordsLinked to original sources
PubMed2002

Effects of hypotonicity on amino acid release in adult Echinostoma caproni as determined by thin layer chromatography.

Thin layer chromatography (TLC) was used to analyze the amino acids in worm incubates isotonic and hypotonic to the intestinal habitat of adult Echinostoma caproni and to analyze the free pool amino acids of these trematodes after incubation. Qualitative analysis revealed the presence of histidine, lysine, alanine, and proline in all samples of incubate and worm tissue. Quantification of histidine and lysine by TLC with densitometry gave mean concentrations of 24.1 micro g histidine/g worm per ml incubate in Locke's solution and 195.0 micro g lysine/g worm per ml incubate in deioinized (DI) water. Quantification of histidine and lysine in the worm tissue gave mean weight percents of 0.0587 and 0.0263, respectively, in worms incubated in Locke's solution and 0.0229 and 0.0163, respectively, for worms incubated in DI water. Our findings suggest that E. caproni adults may leak amino acids for osmoregulation in hypotonic environments.

Amino Acids↗
PubMed2002

Effects of Euhaplorchis californiensis (Trematoda) infection on metallic ions in the host snail Cerithidea californica (Gastropoda).

Graphite furnace atomic absorption spectrometry and ion chromatography were used to study the metallic ions in the digestive gland-gonad complex (DGG) of Cerithidea californica snails infected with the daughter rediae and cercariae of Euhaplorchis californiensis and in uninfected DGGs. Seven metals (calcium, copper, iron, magnesium, potassium, sodium, zinc) were found to be present in infected and uninfected DGGs at concentrations above the minimum levels required for detection. Of these, calcium was present in significantly higher amounts (Student's t-test, confidence level of 95%) in the infected versus uninfected DGGs; magnesium occurred in significantly lower amounts in the infected DGGs. Our results were compared with a previous study that analyzed metallic ions in the DGG of Helisoma trivolvis naturally infected with Echinostoma trivolvis. That study reported a significant elevation of sodium but a reduction of magnesium and manganese in the DGG of infected snails. Variations in the results of the two studies reflect intrinsic differences in the larval trematode-snail systems used.

Animals↗
PubMedDate not supplied

Determination of the active ingredient loperamide hydrochloride in pharmaceutical caplets by high performance thin layer chromatography with ultraviolet absorption densitometry of fluorescence quenched zones.

A quantitative method using silica gel HPTLC plates with fluorescent indicator, automated sample application, and automated UV absorption densitometry of the fluorescence quenching zones was developed and validated for determination of loperamide hydrochloride in anti-diarrheal medications. Samples of three brands of caplets assayed within 96.0-105% of the 2 mg label value. Repeatability was 3.3%, 1.6%, and 2.8% (RSD) for replicate analyses (n=6) of three tablets. The errors of a blank-spike and standard analyses performed to evaluate accuracy were 2.00% and 2.02%, respectively. The method is suitable for application in a drug manufacturing quality control or regulatory analysis laboratory.

Antidiarrheals↗
PubMedDate not supplied

Miniature spectrometers.

The Field Guide to Instrumentation series of articles reviewing commercial analytical chemistry instruments has been published in Inside Laboratory Management starting in 1997 through the March/April 2003 issue. The articles have covered a wide array of subjects, including gas and liquid chromatography, atomic and molecular spectrometry, sample preparation, electroanalysis, microscopy, laboratory software, moisture analysis, and particle size analysis. Each article usually includes a general introduction to the topic, descriptions of selected available instruments, applications, references, a bibliography of other information sources, and contact information for manufacturers. It was decided that the content of these articles makes them more appropriate for publication in the Journal of AOAC INTERNATIONAL, and starting with this issue A Field Guide to Instrumentation will be a regular feature.

Spectrum Analysis↗
PubMedDate not supplied

Recent advances in the thin-layer chromatography of pesticides: a review.

Advances in the applications of thin-layer chromatography (TLC) and high-performance TLC for the separation, detection, identification, and determination of pesticides, other agrochemicals, and related compounds are reviewed for the period 2000-2002. Analyses are described for a variety of samples, such as food, biological, and environmental samples, and for residues of pesticides of various types, including insecticides, herbicides, and fungicides, belonging to different chemical classes. References are included for residue analysis, hydrophobicity studies, and the use of TLC and thin-layer radiochromatography for studies of pesticide metabolism, degradation, uptake, and related topics.

Chromatography, Thin Layer↗