Genetic and epigenetic differences associated with environmental gradients in replicate populations of two salt marsh perennials.

While traits and trait plasticity are partly genetically based, investigating epigenetic mechanisms may provide more nuanced understanding of the mechanisms underlying response to environment. Using AFLP and methylation-sensitive AFLP, we tested the hypothesis that differentiation to habitats along natural salt marsh environmental gradients occurs at epigenetic, but not genetic loci in two salt marsh perennials. We detected significant genetic and epigenetic structure among populations and among subpopulations, but we found multilocus patterns of differentiation to habitat type only in epigenetic variation for both species. In addition, more epigenetic than genetic loci were correlated with habitat in both species. When we analysed genetic and epigenetic variation simultaneously with partial Mantel, we found no correlation between genetic variation and habitat and a significant correlation between epigenetic variation and habitat in Spartina alterniflora. In Borrichia frutescens, we found significant correlations between epigenetic and/or genetic variation and habitat in four of five populations when populations were analysed individually, but there was no significant correlation between genetic or epigenetic variation and habitat when analysed jointly across the five populations. These analyses suggest that epigenetic mechanisms are involved in the response to salt marsh habitats, but also that the relationships among genetic and epigenetic variation and habitat vary by species. Site-specific conditions may also cloud our ability to detect response in replicate populations with similar environmental gradients. Future studies analysing sequence data and the correlation between genetic variation and DNA methylation will be powerful to identify the contributions of genetic and epigenetic response to environmental gradients.

A pseudo-outbreak of salmonellosis.

during July 1991, a single laboratory reported an increased number of an unusual salmonella isolate. An outbreak control team was convened. A case was defined as an individual with diarrhoea from whose faecal sample Salmonella hadar was isolated after 1 July 1991. By 30 July, 90 isolates had been identified and 57 persons interviewed including 39 primary cases. Interviews failed to identify any common features among the cases. A review of the laboratory procedures revealed that the selenite enrichment medium was inoculated using the spoon from the stool collection kit after it was used to emulsify the faecal sample with saline for microscopy. Salmonella hadar was isolated from this saline. Once this practice was stopped, no further isolates of S. hadar were made. This pseudo-outbreak is a powerful reminder to verify the existence of an outbreak, especially when epidemiological data are inconsistent.

Effect of 1% mandelic acid as a bladder irrigation fluid in patients with in-dwelling catheters.

The effect of 1% mandelic acid bladder washouts on 40 patients who were using in-dwelling catheters was studied. The procedure appeared to benefit those colonised with Pseudomonas species but not those colonised with Proteus species. The subject of bladder irrigation is briefly reviewed.

Reactive arthritis due to Salmonella schwarzengrund in a patient with asymptomatic spondylitis.

Reactive arthritis following enteric infection with Salmonella schwarzengrund, a species not previously described in association with this condition, occurred in a 51-year-old man with bilateral sacro-iliitis.

Ethnography: contributions to nursing research.

Health and illness behaviour occur within a cultural context. Ethnographic methodology facilitates an investigation of the context in which people's health beliefs and practices evolve as well as serving to identify the cultural components of health and illness. Ethnography is primarily an inductive mode of research which may utilize several methods of data collection. Participant observation, used in conjunction with interviewing, is the most frequently used data-gathering technique. Sampling procedures in ethnography must be addressed in relation to persons interviewed and/or observed, events to be seen, topics to be considered and time frames to be established. The ethnographic method creates difficulties in establishing reliability as techniques for gathering data are highly individualistic and involve a complex admixture of observations, structured and unstructured interviews, and other procedures. The lengthy stay in a community, as well as the extensive and in-depth data-collection procedures contribute to validity of the findings and their interpretation. Data analysis is time consuming and complex. Ethnography is concerned with the context of discovery, rather than verification, and leads to narrative descriptions and interpretations of cultural phenomena. Ethnography is a means for gaining access to the health beliefs and practices of a culture. In a practice profession such as nursing, improved understanding of the meaning of clients' behaviour will enhance nursing judgements and improve nursing care.

Allergic contact dermatitis in two machinists.

Two machinists were seen whose chronic hand dermatitis was explained by allergic sensitivity to a biocide, Tris Nitro (2-[hydroxymethyl]-2-nitro-1,3-propanediol), which was added to their metalworking fluids (cutting oils) to prevent rancidity. The cause of the men's difficulty was first suspected when they had positive patch test reactions to a related biocide, Bronopol (2-bromo-2-nitropropane-1,3-diol), which we added to our standard screening tray because of its presence in more than 500 cosmetic formulations. The detective skills of the patients uncovered the chemical, Tris Nitro, related to Bronopol in their work environment. Most cases of dermatitis seen in machinists are irritant in origin. As we achieve better cooperation from the metalworking fluid industry, perhaps an increasing number of allergens will be identified. When this occurs, a cooperative manufacturer can be invaluable in directing a machinist to a replacement--a well-preserved cutting fluid free of the allergen.

Ketoconazole in griseofulvin-resistant dermatophytosis.

The efficacy of ketoconazole was evaluated in twenty patients with chronic dermatophyte infections who had failed to clear with griseofulvin therapy. Trichophyton rubrum was the causative organism in nineteen of the patients, and Trichophyton mentagrophytes in one patient. Three of twelve organisms tested showed in vitro resistance to griseofulvin. Duration of infection ranged from 2 to 28 years. Patients received 200 to 400 mg of ketoconazole daily for periods up to 8 months. In addition, patients were followed for 5 months post-therapy to monitor recurrences. Clearing was seen clinically as early as 2 weeks, and by 18 weeks all patients showed marked improvement or clinical clearing, though only six achieved complete mycologic cure. Improvement followed a predictable sequence of sites, with lesions of the trunk healing first, followed by hands, feet, and finally, nails. After 8 months, though all patients showed proximal nail clearing, onychomycosis persisted in thirteen of twenty affected sites. By 5 months post-therapy, four of six patients who had achieved clearing of skin and nails showed recurrences. No significant side effects were observed during therapy, though rare, apparently idiosyncratic cases of hepatotoxicity have been reported. Ketoconazole is an affective therapeutic agent for griseofulvin-resistant dermatophytosis. Apparent cures may subsequently recur after discontinuation of therapy.

Leptospirosis in trout farmers.

A worker on a trout farm died from serologically confirmed leptospirosis. Four other workers at the trout farm had recently had an influenza-like illness; one had had jaundice. The man with jaundice had high leptospiral antibody titres, and two others had titres of 1/30. The remaining serum sample was negative. Family members and neighbours not associated with the farm had no detectable leptospiral antibodies. There was evidence of rat infestation around the ponds and in a shed used for storing trout food. Pond water or trout food contaminated with rat urine is believed to have been responsible for the outbreak. Another case occurred in a fish farmer elsewhere and it is thought he was infected through wading in rat polluted water with defective rubber boots. A survey to determine the incidence of leptospirosis in fish farm workers is under way.

Oral therapy with ketoconazole for dermatophyte infections unresponsive to griseofulvin.

Oral ketoconazole therapy was evaluated with 21 patients who had recalcitrant dermatophytosis. During an 18-week period, all patients, including three with organisms resistant to griseofulvin in vitro, showed impressive clinical improvement. The four patients without nail involvement became mycologically negative earlier than those with onychomycosis. The latter group showed progressive clearing of the nails, but only three were mycologically clear after 18 weeks. Adverse reactions to ketoconazole were negligible, and no patients required discontinuance of the drug. Ketoconazole appears to be a safe, effective drug for oral therapy of dermatophytoses in humans.

Two cases of perinatal listeriosis.

Two cases of neonatal listeriosis are described. The incidence in the UK is given and the treatment of the pregnant woman is briefly discussed.

A search for faecal viruses in new-born and other infants.

Faecal specimens were collected at weekly intervals over the winter months from 141 new-born infants without diarrhoea. Contrary to the findings in other studies, no viruses were detected by electron micriscopy or culture in any of these specimens. Over the same period faecal specimens were collected from 84 infants up to four years of age admitted to hospital. Rotaviruses or adenoviruses were found in 48% of infants with gastroenteritis. Enteroviruses and other small round virus-like particles were found in infants both with and without gastroenteritis. No viruses or pathogenic bacteria could be found in 34% of specimens from infants with gastroenteritis.

Listeriosis.

The incidence, clinical picture, natural history, epidemiology and sequelae of perinatal listeriosis are discussed along with treatment and diagnosis.

The provision of bacteriologically safe infant feeds in hospitals.

Infant feeds, to be safe, must be free from potentially pathogenic organisms but not necessarily sterile. In-bottle terminal heating is the preferred means of producing such feeds and the advantages and disadvantages of high and low pressure heating methods, including the effect upon the food value of the feeds, are discussed. The safety of a low pressure method in use in Princess Alexandra Hospital, Harlow is described. The choice of method of provision of safe feeds; terminal heating in a central milk kitchen or obtaining a commercial supply should be decided on economic grounds. Hospitals using such commercial supplies, however, should make provision for training mothers in the hypochlorite method of disinfection of bottles and teats and also ensure that their trainee nurses and midwives still receive adequate instruction in the hygiene of feed preparation.

Tetracycline-resistant beta-haemolytic streptococci in South-west Essex: decline and fall.

The prevalence of tetracycline-resistant beta-haemolytic streptococci in South-west Essex has been recorded over the past 10 years. It has fallen from a peak of 35% in 1965 to a level of 9.2% in 1972. Ear infections no longer provide the highest incidence of these organisms; vaginal, perineal, and skin infections now seem to be of greater relative importance but throat swabs still provide the greatest actual number of isolations. Erythromycin-resistant strains are still rare.