S Lane

Current trends in research into the waterborne parasite Giardia

The waterborne flagellated parasite Giardia intestinalis continues to be the most frequent protozoan agent of intestinal disease world-wide, causing an estimated 2.8 x 108 cases per annum. Severe symptoms of diarrhea and sickness can be persistent and even life threatening in the immunocompromised, in infants, and in the aged, although self-limiting in the majority of patients. Despite a growing awareness and intensified research many uncertainties remain, especially with respect to the risk of potential zoonotic transmission. Water supplies can be monitored for cysts using automated cytofluorimetric immunoassays, but this does not measure infectivity. Filtration provides the best protection, because cysts are highly resistant to chlorine and ozone. Other incompletely elucidated aspects include mechanisms of pathogenicity, host reaction to infection, immunity and parasite control using vaccines or antigiardial compounds; the 5-nitroimidazole metronidazole is the most effective of these. Molecular typing of various isolates indicates that most animal parasites are not infective to humans, but those that are can be genotypically classified as assemblage A or B. The phylogeny of the organism remains uncertain, but there is a growing opinion that Giardia is not an ancient primitive eukaryote, but that it is derived from a more complex mitochondria-containing protozoon.

The Measurement and Health Impact of Endotoxin Contamination in Organic Dusts from Multiple Sources: Focus on the Cotton Industry

Endotoxin is derived from Gram-negative bacterial membranes, and its inflammatory effects following inhalation are well characterized. The significance of this fact becomes apparent when the wide-ranging environments containing high levels of this microbial product are considered. Endotoxin is present in numerous industrial environments, especially where organic fibers are processed. Microbial contamination of these fibers mainly occurs at the agricultural stage. Materials such as flax and hemp are affected in this way, but the most important product in this context is cotton, from which chronic dust inhalation causes the disease byssinosis. Despite the fact that endotoxin constitutes a significant threat to public health, there are currently no occupational exposure limits for this toxicant. This communication describes the toxicology of endotoxin, and its role in inhalation-induced disease, focusing on measurement of airborne endotoxin in the occupational and domestic environments using the Limulus amebocyte lysate (LAL) enzyme assay. Following the success of the LAL assay for measuring endotoxin in dusts, our laboratory has examined its application to aqueous washes from cotton fibers. Reproducibility of the results was high, and data are presented displaying levels of endotoxin contamination in fibers from different cotton producing countries. Hence, worldwide comparison of industrial endotoxin concentrations can be readily made using this test. It would be highly desirable if the performance of the LAL assay facilitated introduction of industrial endotoxin safety limits, and in spite of minor surmountable shortcomings, the test is accurate, reliable, and well field-tested, so its continued widespread use may achieve this goal.

The influence of celebrity chefs on a student population

Purpose – The purpose of this paper is to investigate the exposure of a student population to celebrity chef television programmes, to assess the influence these figures have, and how they are perceived. Design/methodology/approach – A survey was conducted through an online questionnaire distributed at Bath Spa University. The approach included asking respondents why they watched programmes featuring celebrity chefs; to select a named celebrity chef whom they thought had most influenced their food habits, and to name particular chefs relating to campaign descriptions. Findings – A significant proportion of the study group watched television programmes fronted by celebrity chefs (84 per cent); the main reason for watching was for entertainment. Overall, reported influence was insignificant, though Jamie Oliver was selected as the chef with most influence on the respondent’s food habits. Jamie Oliver’s campaign to improve school dinners was also the most recognised, and celebrity chefs were generally viewed...

Correlative Measurement of Four Biological Contaminants on Cotton Lint, and Their Implications for Occupational Health

Abstract Four biological contaminants of cotton fibers (gramnegative bacterial cells, endotoxin, fungal cells, and (1-3)-(3-D-glucan)were measured in 13 cotton lint samples from international origins, using traditional microbio-logical spread plating and adaptation of the Limulus amoebocyte lysate (LAL) assay. Correlations were evaluated using Spearmans rank correlation analyses. Contamination levels ranged from 713 ± 212 to 216,830 ± 30,413 CFU/g gram-negative bacteria; 281 ± 29 to 9,250 ± 820 CFU/g fungal cells; 8.30 ± 0.89 to 137.89 ± 21.55 ng/g endotoxin; and 15.96 ± 5.18 to 2,964.42 ± 313.90 LAL-reactive units/g glucan. Positive correlations existed between all contaminants; however, they were significant only between fungal cells and glucan (P < 0.05) and between endotoxin and glucan (P < 0.01). The highly significant positive correlation between endotoxin and glucan has implications for the health risk posed by the cotton-production environment, as simultaneous inhalation of these agents may cause or exacerbate lung inflammation.

Biological contamination parameters of cotton lint as biomarkers for fibre quality; a preliminary study.

It has been reported for several decades that microbes, which naturally contaminate cotton fibres during crop growth and subsequent storage can have an adverse effect on the structural quality of cotton lint. Although several studies have analysed the relationship between numbers of Gram-negative bacteria or bacterial endotoxin and particular physical properties, these studies have been limited to cotton from the United States, and the possible effects of fungal contamination have not been examined in detail. This study quantified the Gram-negative bacteria and fungal cells, as well as measuring concentrations of bacterial endotoxin and fungal glucan, on cotton lint samples from international sources. Spearman’s rank correlation coefficients calculated between these results and quality data analysed by an automated testing instrument revealed several significant correlations. Findings included inverse correlations between the biological contamination parameters and fibre elongation, micronaire and reflectance. The possible causes and implications of these findings were also discussed.

The Fungal Profile of Cotton Lint from Diverse Sources and Implications for Occupational Health

There is mounting evidence that inhalation of fungal spores and their fragments and toxins may cause respiratory illness, particularly in indoor environments and industrial settings. However, analysis of these organisms on cotton has not been carried out in detail and, hence, further examination may prove important in identifying sources of these organisms and assessing the risks posed to cotton workers. This study identified fungi from cotton lint samples originating in 12 world regions and revealed six different fungal genera, with the following rank order of sample isolation incidence: Aspergillus > Cladosporium > Fusarium > Rhizopus > Penicillium > Alternaria. Aspergillus was the most common genus and Aspergillus niger in particular was the pecies most frequently identified. Improved understanding of the variety of organisms that contaminate cotton may help to reduce prevalence of organic dust-related lung diseases.

The fungal profile of cotton fibres, associated toxins and wider implications for indoor health

mean gastric emptying times, measured by t50 (time taken for 50% of the Clinutren ISO to leave the stomach and t90 (time taken for 90% of the Clinutren ISO to leave the stomach) in the fed and fasted state (Table 1). A robust and reproducible model of the gastric emptying of a new nutrient liquid meal is described, which shows similar emptying kinetics in the fasted and the post-prandial conditions.

The measurement of endotoxin on cotton fibres and implications for industrial health

Preparations containing extracts from Arnica montana (Leopard’s bane) are used for symptomatic relief from arthritis, local skin irritation and inflammation and bruising. Using a methanolic tincture prepared from Spanish A. montana flower heads, we have previously shown that sesquiterpene lactones from the plant extract were able to traverse human skin in-vitro, though at very small levels (Tekko et al 2003); here we report an in-vivo study showing that vasoactive agents are present in this tincture. A commercially available stock tincture of A. montana in ethanol–water (45:55, v/v) was obtained (Herbal Apothecary). A more concentrated solution in methanol– water (50:50, v/v) was prepared from this tincture to provide Arnica constituents at 10-times the initial concentration. Additionally, a sesquiterpene lactone extract was obtained from the stock tincture by evaporation under vacuum at ambient temperature to half its volume followed by extraction with methylene chloride–ethyl acetate (50:50, v/v) according to Leven & Willuhn (1987). This fraction was reconstituted into methanol–water (50:50, v/v) to give a 10-fold concentrated sesquiterpene lactone extract solution. Samples (15 L) of the concentrated test solutions (tincture and sesquiterpene extracts) or the controls (methanol–water (50:50, v/v), betamethasone and nicotinic acid) were applied to duplicate occluded template areas on the ventral forearm of two subjects (with their informed consent). After 3 h, a quantitative assay of vasoactivity was obtained by examining change in the skin site’s 1931 CIE chromaticity co-ordinates using a PR-650 Spectrascan Colorimeter (Photo Research Inc., Chatsworth, CA). This device gives a measure of any colour shift and was validated using betamethasone (vasoconstrictor, skin blanching) and nicotinic acid (vasodilator, erythema). After 3 h, vasodilation was clearly observed with the concentrated tincture and this was accompanied by a change in the measured chromaticity co-ordinates of the skin surface towards the red region of the chromaticity space of 13.5 10 3 8 10 3 (mean s.d., n1⁄4 4). This effect was similar to that of nicotinic acid 1%, w/v 12.7 10 3 4.9 10 3 in comparison with the blank solution which resulted in a shift of 1.9 10 3 2.3 10 . Moreover, the concentrated sesquiterpene lactone extract showed similar activity to the entire concentrated tincture with a similar shift in chromaticity co-ordinates of 11.7 10 3 9 10 3 (mean s.d., n1⁄4 4). This provides evidence to support our earlier suggestion that it is the sesquiterpene lactone fraction within Arnica montana that provides some of the activity reported for these preparations. Additionally, the rubefacient activity of the sesquiterpene lactone concentrate was still apparent on one subject up to 48 h post-application and so it can be concluded that these components from Arnica could have a profound vasodilatory effect if judiciously formulated.