scholarly journals Factitious Diarrhea Induced by Stimulant Laxatives: Accuracy of Diagnosis by a Clinical Reference Laboratory Using Thin Layer Chromatography

2007 ◽  
Vol 53 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Joseph H Shelton ◽  
Carol A Santa Ana ◽  
Donald R Thompson ◽  
Michael Emmett ◽  
John S Fordtran
Keyword(s):  
United States ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Stool Specimen ◽  
False Negative ◽  
The United States ◽  
Positive Zero ◽  
Reference Laboratory ◽  
Clinical Value ◽  
Layer Chromatography

Abstract Background: Surreptitious ingestion of laxatives can lead to serious factitious diseases that are difficult to diagnose. Most cases involve ingestion of bisacodyl or senna. Thin layer chromatography (TLC) of urine or stool is the only commercially available test for these laxatives. Such testing is considered highly reliable, but its accuracy in clinical practice is unknown. Our aim was to evaluate the reliability of TLC laxative testing by a clinical reference laboratory in the United States. Methods: Diarrhea was induced in healthy volunteers by ingestion of bisacodyl, senna, or a control laxative (n = 11 for each laxative group). Samples of urine and diarrheal stool were sent in blinded fashion to the clinical reference laboratory for bisacodyl and senna analysis. Results: TLC testing for bisacodyl-induced diarrhea revealed a sensitivity of 73% and specificity of 91% when urine was tested and sensitivity and specificity of 91% and 96%, respectively, when stool was analyzed. When diarrhea was induced by senna, the TLC assay for senna failed to identify even a single urine or stool specimen as positive (zero% sensitivity). Conclusions: Considering the expected prevalence of surreptitious laxative abuse in patients with chronic idiopathic diarrhea (2.4%–25%, depending on the clinical setting), TLC of urine or stool for bisacodyl by this reference laboratory would often produce misleading results, and testing for senna would have no clinical value. The major problems are false-positive tests for bisacodyl and false-negative tests for senna.

Rapid Screening of Pharmaceuticals by Thin-Layer Chromatography: Analysis of Essential Drugs by Visual Methods

1995 ◽  
Vol 78 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Allen S Kenyon ◽  
Paul E Flinn ◽  
Thomas P Layloff
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
The United States ◽  
World Health ◽  
Rapid Screening ◽  
Visual Methods ◽  
Screening Process ◽  
Standard Dosage ◽  
Essential Drugs ◽  
Layer Chromatography

Abstract A method for rapidly screening pharmaceuticals by thin-layer chromatography has been designed for use in areas with limited resources and by operators with limited training. An apparatus for performing the analysis in a plastic bag under equilibrium conditions was designed. Results can be reproduced by different operators and in different locations. The analysis can be performed without electricity or in a remote area, away from a laboratory. It is especially suited for field use in developing countries. The method is low cost, maintenance-free, fast, and reliable; it also uses limited volumes of solvents. The analyses can be performed without weighing if reference materials can be supplied in tablet form, provided the drug content is listed and only one unit is required for each analysis. All procedures were developed for the analysis of drugs from a partial list of essential drugs established by the World Health Organization. Three drugs were selected and prepared in the form of reference tablets. Comparisons with the analyses of the drugs in standard dosage forms were made by using reference tablets and primary USP standards. Comparable results were obtained, proving that the screening process can be conducted by using reference tablets and without weighing either the sample or the reference. The method has been successfully demonstrated and used in Swaziland, by high school teachers in the United States, and by personnel from the Ministry of Health in Saudi Arabia. Personnel can be trained in a short time to perform screening analysis of drugs.

Crystals in the wood of the genus Abies indigenous to Canada and the United States

1968 ◽  
Vol 46 (10) ◽  
pp. 1221-1228 ◽  
Author(s):  
R. W. Kennedy ◽  
C. B. R. Sastry ◽  
G. M. Barton ◽  
E. L. Ellis
Keyword(s):  
United States ◽  
Thin Layer ◽  
Calcium Oxalate ◽  
Wood Species ◽  
Juvenile Wood ◽  
The United States ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Ray Parenchyma Cells ◽  
Layer Chromatography

The scanty and conflicting literature on distribution and nature of crystals in the ray parenchyma of Abies is reviewed before results are presented from this study of 318 trees. Crystals of rhomboidal and elongated forms were regularly present, in descending order of frequency, in A. concolor, A. grandis, A. magnifica, A. bracteata, and A. procera. Crystals were deposited predominantly in marginal ray parenchyma cells which died prematurely within a critical zone of sapwood. Both forms of crystals were regularly lacking in A. amabilis, A. balsamea, A. fraseri, and A. lasiocarpa, although fairly frequently elongated types were found in certain samples of the latter species. A pattern of very infrequent crystal distribution was found in association with juvenile wood in a single mature A. grandis, and in seedlings or saplings of several species.A quantitative scale of crystal frequency was developed and its application to wood species identification demonstrated. The lack of crystals in A. amabilis is offered along with other evidence to suggest a relationship between this species and those of the series Lasiocarpae Franco.Chemical characterization by thin-layer chromatography, atomic absorption, and histochemical procedures confirmed the older supposition that both forms of ray parenchyma crystals were calcium oxalate.

scholarly journals The Study of Ranitidine Interference With Morphine Detection Test by Thin-Layer Chromatography

2018 ◽  
Vol 6 (1) ◽  
pp. 21-23
Author(s):  
Amir Miri ◽  
Amir Karami ◽  
Fourogh Nadi ◽  
Fatemeh Zeraati
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Drugs Of Abuse ◽  
False Negative ◽  
Urine Samples ◽  
Urine Drug Screen ◽  
Test Results ◽  
Two Samples ◽  
Before And After ◽  
Layer Chromatography

Background: Drug abuse is a global and critical problem. One of the most frequent practices done in order to detect the drugs of abuse is Urine Drug Screen. However, for changing the drug test results, adulterants and urine substitutes are being designed. As the referring people’s background has shown, ranitidine is one of the interfering drugs in morphine detection test. Therefore, in the present study, the interference of ranitidine in morphine detection test will be studied. Methods: Ten healthy volunteers who had not used any kind of drug for 72 hours before the test were recruited into the study. First, 2 doses of ranitidine (150 and 300 mg) were administered to the subjects orally and 100-mL urine samples were collected from them before and after taking ranitidine. The second urine sample was collected at 6-8 am. Ten micrograms morphine was added to both urine samples of each individual. The urine samples were tested using thin-layer chromatography (TLC) technique. The experiment was repeated after 1 week using ranitidine 300 mg. Results: The TLC test was carried out on 40 urine samples. Twenty samples were tested before and, the rest, after ranitidine consumption. The TLC test results were positive before ranitidine consumption but negative for 18 samples and positive for two samples after taking ranitidine. Conclusion: Ranitidine may change the urine morphine screening test results via TLC method and induce a false negative result.

scholarly journals Comparison of thin-layer chromatography, spectrofluorimetry and bright greenish-yellow fluorescence test for aflatoxin detection in corn

2010 ◽  
Vol 53 (3) ◽  
pp. 687-692 ◽  
Author(s):  
Elisabete Yurie Sataque Ono ◽  
Marcelo da Silva ◽  
Ricardo Marcelo Reche Ribeiro ◽  
Mario Augusto Ono ◽  
Luciana Hayashi ◽  
...  
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
False Negative ◽  
Screening Method ◽  
Yellow Fluorescence ◽  
Negative Results ◽  
Greenish Yellow ◽  
False Negative Results ◽  
Fluorescence Test ◽  
Layer Chromatography

In this study the bright greenish-yellow fluorescence test, widely used by the corn milling industry, was compared to the thin-layer chromatography (TLC) and spectrofluorimetry methods for aflatoxin detection in 40 corn samples naturally contaminated by the Aspergillus section Flavi. According to the corn processing industry criteria, all the samples were adequate for human and animal consumption by the bright greenish-yellow fluorescence test, but TLC and spectrofluorimetry analysis detected aflatoxins above the maximum tolerated limit (20 µg/kg) in 7 and 8 samples, respectively. Aflatoxins were detected in 16 (40%) corn samples by TLC, with levels ranging from 4.0 to 54.0 µg/kg (mean 19.97 ± 15.97 µg/kg), and in 25 (62.5%) samples by spectrofluorimetry, with levels ranging from 1.0 to 58.66 µg/kg (mean 17.14 ± 17.81 µg/kg). The results indicated a good correlation (ρ = 0.97) between TLC and spectrofluorimetry for aflatoxin determination in naturally contaminated corn. The bright greenish-yellow fluorescence test was simple and quick, but it showed 20% false-negative results, suggesting its use only as screening method for detecting the suspected lots of grains that should be tested further for aflatoxin by more sensitive methods.

scholarly journals What’s in the box? Authentication ofEchinaceaherbal products using DNA metabarcoding and HPTLC

2017 ◽  
Author(s):  
Ancuta Cristina Raclariu ◽  
Carmen Elena Ţebrencu ◽  
Mihael Cristi Ichim ◽  
Oana Teodora Ciupercǎ ◽  
Anne Krag Brysting ◽  
...  
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
High Performance ◽  
The United States ◽  
Infrared Spectrometry ◽  
Herbal Products ◽  
Analytical Strategy ◽  
Regulatory Policies ◽  
Dna Metabarcoding ◽  
Layer Chromatography

AbstractBackgroundDifferences in regulatory policies between countries as well as a lack of appropriate standardized methods for authentication and quality control of herbal products lead to concerns over quality and safety.Echinaceaproducts are among the top selling herbal products in Europe and the United States with indications for broad range of ailments.PurposeThis study approached the need for a novel analytical strategy in authentication of herbal products.MethodsA combination of high performance thin layer chromatography (HPTLC) and DNA metabarcoding was employed. Fifty-threeEchinaceaherbal products marketed across Europe were tested to evaluate the accuracy of these methods in plant identification and their potential in detecting substitutes, adulterants and other unreported plant constituents.ResultsHPTLC provides a high resolution in detectingEchinaceaphytochemical target compounds, but does not offer information on the other species within the product. Alternatively, we showed that the limitation of HPTLC to detect non-targeted species can be overcome through the complementary use of DNA metabarcoding. Using DNA metabarcoding,Echinaceaspecies were detected in 34 out of the 38 retained products (89 %), but with a lack of discriminatory resolution at the species level due to the low level of molecular divergence within theEchinaceagenus. All herbal products showed considerable discrepancies between ingredients listed on the label and the ones detected using DNA metabarcoding registering an overall ingredient fidelity of 43 %.ConclusionThe results confirm that DNA metabarcoding can be used to test for the presence ofEchinaceaand simultaneously to detect other species present in even highly processed and multi-ingredient herbal products.AbbreviationsEMAEuropean Medicines AgencyBLASTbasic local alignment search toolFTIRFourier-transformed infrared spectroscopyIRinfrared spectrometryHPTLChigh performance thin layer chromatographymatKmaturase KMSmass spectrometryMOTUmolecular taxonomic unitnrITSnuclear ribosomal internal transcribed spacerPh.Eur.European PharmacopoeiarbcLribulose bisphosphate carboxylaseTLCthin-layer chromatographyUV-VISultraviolet-visible

Thin-Layer Chromatography

1965 ◽  
Author(s):  
H. R. Bolliger ◽  
M. Brenner ◽  
H. Gänshirt ◽  
Helmut K. Mangold ◽  
H. Seiler ◽  
...  
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Layer Chromatography
Sign in / Sign up

Export Citation Format

Share Document