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Biomedical subjects

Joseph Sherma

Publications and source records attributed to Joseph Sherma.

At least 19 recordsLinked to original sources
PubMed2006

Thin layer chromatographic analysis of glucose and maltose in estivated Biomphalaria glabrata snails and those infected with Schistosoma mansoni.

Thin layer chromatography was used to analyze the glucose and maltose concentrations of the digestive gland-gonad complex (DGG) of uninfected-estivated Biomphalaria glabrata snails and estivated B. glabrata patently infected with Schistosoma mansoni. All snails were estivated in a most chamber at a relative humidity of 98+/-1% and a temperature of 23+/-1 degrees C for 14 days. Carbohydrates were extracted from the DGG with 70% aqueous ethanol, and extracts were analyzed on silica gel preadsorbent plates using ethyl acetate-glacial acetic acid-methanol-water (60:15:15:10) mobile phase, alpha-naphthol-sulfuric acid detection reagent, and quantification by densitometry. The concentrations of glucose and maltose were significantly reduced in both uninfected-estivated snails and infected-estivated snails.

Animals↗
PubMed2006

High-performance thin-layer chromatographic analysis of neutral lipids and phospholipids in Biomphalaria glabrata patently infected with Echinostoma caproni.

This study examined the effects of larval trematode infection on the neutral lipid and phospholipid content of Biomphalaria glabrata patently infected with the daughter rediae of Echinostoma caproni. Uninfected snails were used as matched controls. As determined by qualitative high-performance silica gel thin-layer chromatography (HPTLC), the major neutral lipids present in the whole bodies and digestive gland-gonad complexes in both snail populations were free sterols, free fatty acids, and triacylglycerols, and the major polar lipids were phosphatidylcholine and phosphatidylethanolamine. Quantitative analysis by HPTLC with visible and UV scanning reflectance densitometry showed no significant differences in the concentrations of these lipids in whole bodies of infected snails vs the controls, but the concentration of triacylglycerols in the infected digestive gland-gonad complex was significantly less than that of the uninfected. No qualitative differences in neutral lipids and phospholipids in shell or plasma samples were found between infected vs uninfected snails.

Animals↗
PubMed2005

Effects of diet on the carotenoid pigment and lipid content of Pomacea bridgesii as determined by quantitative high performance thin layer chromatography.

High performance thin layer chromatography was used to quantify the concentrations of beta-carotene and lutein in the whole bodies and digestive gland-gonad complexes of Pomacea bridgesii fed on a lettuce diet and a hen's egg yolk diet, and snails starved for one week. beta-carotene and lutein concentrations were determined in the fecal matter of cultures on the lettuce and yolk diets as well. Significantly higher amounts of beta-carotene were found in the whole bodies of snails fed lettuce compared with those starved for a week. beta-carotene was not detected in the whole bodies and digestive gland-gonad complexes of snails fed hen's egg yolk. Neutral and polar lipid levels were also quantified in P. bridgesii fed lettuce and yolk. Significantly higher amounts of triacylglycerols were detected in the digestive gland-gonad complexes of snails maintained on the egg yolk diet.

Animals↗
PubMed2005

Effects of various larval digeneans on the calcium carbonate content of the shells of Helisoma trivolvis, Biomphalaria glabrata, and Physa sp.

The calcium carbonate concentrations in the shells of Helisoma trivolvis and Physa sp. naturally infected with larval trematodes and Biomphalaria glabrata experimentally infected with larval trematodes were analyzed quantitatively. The larval trematode-snail relationships studied were H. trivolvis infected with larval Echinostoma trivolvis and Physa sp. infected with various larval digeneans, and B. glabrata infected with Echinostoma caproni or Schistosoma mansoni. The calcium carbonate concentrations of the shells of infected snails and uninfected cohorts and of the water in which the snails were maintained were determined by ion exchange chromatography. No significant differences in the calcium carbonate concentrations of shells of infected versus uninfected snails were found. The shells of B. glabrata infected with E. caproni contained significantly less calcium carbonate than the shells of uninfected B. glabrata. The hypercalcification hypothesis, i.e., larval trematodes induce an increase in the calcium concentrations in the shells of their snail hosts, was not upheld in any of the snail-larval digenean systems studied herein.

Animals↗
PubMed2004

Effects of tonicity on the release of neutral lipids in Echinostoma caproni adults and observations on lipids in excysted metacercariae.

High performance thin layer chromatography was used to analyze neutral lipids in worm incubates isotonic, hypotonic, and hypertonic to the intestinal habitat of adult Echinostoma caproni. Qualitative analysis revealed the presence of free sterols, free fatty acids, triacylglycerols, and a steryl ester/hydrocarbon fraction in all incubate samples. The most abundant neutral lipid fraction released into the incubation medium was the triacylglycerol fraction. This fraction was quantified after worms were maintained for 2 h at 37.5 degrees C in hypertonic (Locke's 2x solution), isotonic (Locke's 0.5x solution) and hypotonic (deionized water) media. Percentages of triacylglycerols on a wet-weight basis found in Locke's 2x, 0.5x, and deionized water were 0.369, 3.23, and 0.242, respectively, suggesting that the optimal medium to obtain maximal excretory-secretory products is the Locke's 0.5x solution. Histochemical staining of whole excysted metacercariae with oil red O did not detect neutral lipids. Analysis of 500 excysted metacercariae incubated for 2 h at 37.5 degrees C revealed that free sterols, free fatty acids, and triacylglycerols were released in amounts of 16.2, 1.59, and 5.34 ng/organism, respectively. Our results were compared with previous studies on neutral lipids in excysted metacercariae and adults of E. trivolvis. Variations in the results of our study compared with others reflect intrinsic differences in the species of echinostome used.

Animals↗
PubMed2004

Effects of diet and larval trematode parasitism on lutein and beta-carotene concentrations in planorbid snails as determined by quantitative high performance reversed phase thin layer chromatography.

High performance thin layer chromatography (HPTLC) was used to quantify the concentrations of beta-carotene and lutein in Biomphalaria glabrata and Helisoma trivolvis (Colorado and Pennsylvania strains) snails under various conditions. These conditions were: snails fed a lettuce (L) vs. a yolk (Y) diet; B. glabrata infected with Echinostoma caproni vs. uninfected snails; and H. trivolvis (PA) infected with Echinostoma trivolvis vs. uninfected snails. The pigments were extracted from the snail whole bodies and digestive gland-gonad complexes, separated by reversed phase HPTLC, and quantified by densitometric scanning with standard calibration curves. Snails on the L-diet showed significant increases (Student's t-test, P<0.05) in the concentrations of beta-carotene and lutein compared to snails on the Y-diet. Snails infected with echinostomes showed no significant differences (Student's t-test, P>0.05) in the concentrations of lutein and beta-carotene compared to the uninfected cohorts. Our results were compared with previous studies that analyzed beta-carotene and lutein in snails infected with larval trematodes. Variations in the results of our study compared with others reflect intrinsic differences in the larval trematode-snail systems used.

Animals↗
PubMed2004

Free-pool amino acids in Biomphalaria glabrata infected with Echinostoma caproni as determined by thin-layer chromatography.

Thin-layer chromatography was used to analyze the free-pool amino acids of the digestive gland-gonad complex (DGG) of Biomphalaria glabrata infected with Echinostoma caproni and uninfected (control) snails. Qualitative analysis revealed the presence of histidine, lysine, serine, alanine, valine, and isoleucine or leucine in all samples. Quantitative analysis of lysine and valine gave mean weight percentages of 0.00699 +/- 0.0022 and 0.00174 +/- 0.00056, respectively, in the DGG of uninfected snails, and 0.00504 +/- 0.0014 and 0.00254 +/- 0.00033, respectively, in the DGG of infected snails. The differences in values between infected and uninfected snails were not statistically significant (Student's t-test, P > 0.05).

Amino Acids↗
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↗
PubMedDate not supplied

High-performance liquid chromatography/mass spectrometry analysis of botanical medicines and dietary supplements: a review.

This article reviews research on the qualitative and quantitative analysis by high-performance column liquid chromatography/mass spectrometry (LC/MS) and LC/tandem mass spectrometry (LC/MS/MS) of botanical drugs, drug substances or preparations, and finished botanical products. In addition, LC/MS and LC/MS/MS techniques and commercial instruments are described and compared briefly, and prospects for future use of these methods for the analysis of botanicals are suggested. Some applications of direct MS without LC are also described.

Chromatography, High Pressure Liquid↗