Introduction to metabolomics and its applications in ophthalmology.

Metabolomics is the study of endogenous and exogenous metabolites in biological systems, which aims to provide comparative semi-quantitative information about all metabolites in the system. Metabolomics is an emerging and potentially powerful tool in ophthalmology research. It is therefore important for health professionals and researchers involved in the speciality to understand the basic principles of metabolomics experiments. This article provides an overview of the experimental workflow and examples of its use in ophthalmology research from the study of disease metabolism and pathogenesis to identification of biomarkers.

Mouth level smoke exposure using analysis of filters from smoked cigarettes: a study of eight countries.

The analysis of spent cigarette filters enables the estimation of the nicotine and tar (nicotine-free dry particulate matter) yields obtained by smokers in their everyday environment and has been shown to correlate well with biomarkers of exposure. Leading products across the range of ISO tar yields were selected from Australia, Brazil, Canada, Germany, Japan, New Zealand, South Africa and Switzerland. At least fifty demographically representative smokers were recruited per product. Subjects, ≥ 21 years of age and smoking ≥ 5 cigarettes per day, were asked to collect ≥ 15 filters from cigarettes they had smoked. The collected filters were analysed for nicotine and UV absorbance to enable the smokers' mouth level exposure to nicotine and tar to be estimated and a comparison of countries and tobacco blend styles to be made. Smoking history data were also collected. More than 80,000 filters were collected from 5703 smokers of 106 products from eight countries. Mean ± SD estimated nicotine exposures per cigarette and per day ranged from 0.93 ± 0.34 mg/cigarette (Brazil) to 1.77 ± 0.69 mg/cigarette (South Africa) and from 16.4 ± 11.1mg/day (Germany) to 31.5 ± 14.8 mg/day (South Africa), respectively. Male smokers obtained higher mean estimated tar and nicotine exposures than female smokers. These gender differences were statistically significant for six countries. Significant correlations were found between estimated nicotine exposure and ISO nicotine yield, and between estimated tar exposure and ISO tar yield (p<0.001).

A case of atypical polyagglutinability due to Tk-transformation.

A case of acquired transient polyagglutinability in a group O, Rh(D) positive female patient, Wa, is described. An unusual finding in the preliminary serological investigation was the non-reaction of the cells with peanut (Arachis hypogaea) extract. The patient's red cells were strongly agglutinated by normal human and rabbit sera from which anti-T had been removed. Electrophoretic mobility studies and tests with polybrene indicated that their sialic acid content was normal. The use of a specific antiserum raised in a rabbit to Wa cells and cross-absorption tests showed that the patient's erythrocytes shared similar antigenic determinants to red cells treated with supernatants from pure cultures of Bacteroides fragilis. The in vitro-modified red cells reacted strongly with BS II lectin prepared from Bandeiraea simplicifolia seeds thus providing confirmatory evidence for Tk transformation on Wa cells. It is concluded that the Tk receptor is probably a more frequent feature of acquired transient polyagglutinability than has hitherto been recognized.