No / RATIONALE: 5,6-Dimethylxanthenone-4-acetic acid (DMXAA) is a low molecular weight drug of the flavonoid group, which has an anti-vascular effect in tumours causing endothelial cell apoptosis and activation of cytokines. Flavonoid-based compounds have been reported to lead to an upregulation in the expression of lysophosphatidylcholines (LPC)-type lipids in solid tumours. A study employing TLC/MALDI-MS and MALDI-MS imaging to examine LS174T colorectal adenocarcinoma xenografts following administration of DMXAA has been conducted into this effect. METHODS: LS174T colorectal adenocarcinoma xenografts grown in male immune-deficient mice were treated with 27.5 mg/kg DMXAA. The control (before treatment) and 4 h and 24 h post-treatment tumours were excised and divided into two. MALDI-MS imaging experiments were carried out on 12 microm cryosections sections taken from one half of the tumours and from the other half the lipids were extracted and analysed by TLC/MALDI-MS. These experiments were carried out in triplicate. RESULTS: Statistical analysis of the MALDI-MS imaging data set indicated an increased amount of LPC in the 24 h post-treated sample and a decreased amount of PC in the 24 h post-treated sample, compared with the 4 h post-treated sample and the control. These effects were confirmed by the TLC/MALDI-MS data. The lipid extracts were separated into six spots on the TLC plate. These were identified as arising from different lipids classes, i.e. LPC, sphingomyelins (SM), phosphatidylcholines (PC) and phosphatidylethanolamines (PE). The TLC/MALDI-MS data indicated that LPC were highly expressed in the 4 h and 24 h post-treated tumour samples compared with the control. Examination of the mass spectrometric images confirms this increase and demonstrates additionally that the increase in the signals arising from LPC appears to be localised primarily within the central areas of the xenograft. CONCLUSIONS: An increase in expression of LPC lipids in solid tumours treated with DMXAA has been demonstrated and shown to be localised in the central area of the tumour.

A modified ascending thin layer chromatographic technique has been developed which resolves the major phospholipid and neutral lipid classes of five common fluids and tissues. A one-half milliliter sample is extracted with n-butanol:diisopropylether (40:60 by volume, cholesteryl acetate = 100 ng/ul) for thirty minutes and the organic phase is spotted onto a thin layer chromatography plate and carried through three successive chromatographic developments. The lipids are then visualized either by charring with ammonium bisulfate or staining with phosphomolybdic acid. The use of cholesteryl acetate as an internal standard enables quantitation of the phospholipids and neutral lipid classes. This method may be a very valuable, new technique for research and clinical laboratories.

The purpose is to isolate a natural compound, which shows a high activity against Candida albicans, from plant, Vincetoxicum stocksii. Bio-Assay, Thin layer Chromatography, Column Chromatography, TLC bio Assay, and other extraction techniques are used in order to isolate the active compound. First, bio assay technique is carried out on the crude gum. Next, several flash chromatography columns are carried out in order to isolate the target compound, which has a Rf value of ~0.53 in 10:1 DCM/methanol solvent mixture. The TLC bioassay technique is also carried out in order to confirm the hypothesis that the target compound is indeed active.

A sol-gel stationary phase was developed for in-situ infrared (IR) detection of analytes on thin-layer chromatography (TLC) plates. These sol-gel-based TLC plates have improved optical properties compared with conventional TLC plates in IR spectroscopic analysis. Samples can be analyzed in transmission geometry, requiring no special attachments. The sol-gel-based TLC plates demonstrate significantly better light throughput and a wider spectral range than conventional TLC plates analyzed in diffuse reflectance geometries.The sol-gel precursor, methyltrimethoxyorthosilicate (MTES), was templated with cetyltrimethylammonium bromide (CTAB) and urea in order to form a porous sol-gel. Aerosol deposition was used to apply the sol-gel solution onto either glass slides or silicon wafers within an enclosed chamber. Many variables were studied to determine their effect on the quality of the sol-gel stationary phases, including the ratio of MTES:methanol:water:CTAB:urea:HCl:, gelation times and temperatures, and deposition rate. Sol-gel films prepared using MTES/methanol/water/CTAB at ratios of 1 : 20 : 7 : 0.2 containing 5 wt% urea (relative to MTES) and pH 1.5 were crack-free, mechanically stable, and uniform in appearance. The films were tens of microns thick with a highly interconnected porous structure.For chromatographic separations, the films exhibited good solvent migration velocity and could be repeatedly washed and reused for TLC separations without showing degradation in the separation. Several different classes of compounds, including polyaromatic hydrocarbons and dyes, were successfully separated. Theoretical plate values measured on the MTES-based sol-gel films were comparable to those obtained on commercially available TLC plates.

Thesis (M.S.)--Michigan State University. Dept. of Chemistry, 2006. / Title from PDF t.p. (viewed on Nov. 20, 2008) Includes bibliographical references (p. 83-88). Also issued in print.

Thesis (Ph. D.)--Florida State University, 2005. / Advisor: Dr. John G. Dorsey, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (June 15, 2005). Document formatted into pages; contains xiv, 112 pages. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (MSc. (Pharmacology, Faculty of Health Sciences))-University of Pretoria, 2003. / Also available in print format.

Submitted in partial fulfillment of the requirements for the degree of Masters in Technology in Chemistry, M.L. Sultan Technikon, 2000. / Mycotoxins are a group of natural poisons produced by certain strains of fungal species when they grow under favourable conditions on a wide variety of different substrates. These toxins have been implicated in a wide range of acute diseases in man and animals. Their toxic effects include oesophageal cancer and liver diseases in humans, and carcinogenic effects in experimental rats and poultry. Hence, there is a need to monitor toxin levels in food commodities. / M

Recent work in this laboratory has centered around Platinum metals and their coordination compounds. Specifically, Thin-Layer Chromatography of Platinum metal ions has been reported in one of the recent dissertations (1). The purpose of the present work was to carry out a systematic study of Thin-Layer Chromatography on the following complexes: Tetrammine Platinum (II) Chloride [Pt (NH3)4]Cl2 Tetraammine Palladium (II) Chloride. [Pd (NH3)4]Cl2 Hexammine Platinum (IV) Chloride. [Pt (NH3)6]Cl4 Hexammine Palladium (IV) Chloride [Pd (NH3)6]Cl4 After the complexes had been synthesized, the main problem lay in finding a suitable adsorbent and solvent system for separating a mixture of all four complexes as well as an appropriate locating reagent, so that once the separation had been accomplished, complexes could be identified.