Environment, dosage, and pathogen isolate moderate virulence in eelgrass wasting disease.

Eelgrass wasting disease, caused by the marine pathogen Labyrinthula zosterae, has the potential to devastate important eelgrass habitats worldwide. Although this host-pathogen interaction may increase under certain environmental conditions, little is known about how disease severity is impacted by multiple components of a changing environment. In this study, we investigated the effects of variation in 3 different L. zosterae isolates, pathogen dosage, temperature, and light on severity of infections. Severity of lesions on eelgrass varied among the 3 different isolates inoculated in laboratory trials. Our methods to control dosage of inoculum showed that disease severity increased with pathogen dosage from 104 to 106 cells ml-1. In a dosage-controlled light and temperature 2-way factorial experiment consisting of 2 light regimes (diel light cycle and complete darkness) and 2 temperatures (11 and 18°C), L. zosterae cell growth rate in vitro was higher at the warmer temperature. In a companion experiment that tested the effects of light and temperature in in vivo inoculations, disease severity was higher in dark treatments and temperature was marginally significant. We suggest that the much greater impact of light in the in vivo inoculation experiment indicates an important role for plant physiology and the need for photosynthesis in slowing severity of infections. Our work with controlled inoculation of distinct L. zosterae isolates shows that pathogen isolate, increasing dosage of inoculum, increasing temperature, and diminishing light increase disease severity, suggesting L. zosterae will cause increased damage to eelgrass beds with changing environmental conditions.

Increased tissue concentrations of histamine in the duodenal mucosa of children with coeliac disease.

Tissue concentrations of histamine have been estimated in peroral duodenal biopsy specimens from five children with coeliac disease while on a gluten-free diet and after a three-month gluten challenge. Histamine concentrations in the patients on a diet did not differ significantly from a group of control children. However after gluten challenge, histological relapse of the duodenal mucosa in each patient was associated with increased tissue concentrations of histamine. The findings suggest that histamine may be involved in the pathogenesis of the small intestinal mucosal changes in children with coeliac disease.

A study of cytoplasmic oestrogen receptors in patients with breast cancer in a district general hospital.

The tumors of 61 patients suffering from primary adenocarcinoma of the breast were assayed for oestrogen receptors (ER), using the dextran-coated charcoal method. A statistically significant relationship (P less than 0.05) was found to exist between ER status and the histological grade of the tumour. No relationship was found between ER status and either tumour size or the pathological state of the axillary lymph nodes. It is concluded that it is a practical proposition to establish an ER assay service in a district general hospital, with subsequent benefits for the individual patient.

Measurement of the 5-hydroxyindoleacetic acid/creatinine ration in the urine of patients with coeliac disease.

Urinary excretion of 5-hydroxyindoleacetic acid and creatinine has been measured in 8-hour collections from adult patients with coeliac disease, and results have been compared with a group of healthy adult controls. Results were expressed as 5-HIAA/creatinine and significantly higher values of this ratio were found in patients with coeliac disease. Measurement of this ratio is a non-invasive technique which is useful in selecting patients with suspected coeliac disease for further investigation.

Increased tissue concentrations of 5-hydroxytryptamine in the duodenal mucosa of patients with coeliac disease.

Tissue concentrations of 5-HT have been measured in the duodenal mucosa of adults and children with coeliac disease and were found to be significantly higher than those from a control group. This finding may be associated with hyperactivity or hyperplasia of enterochromaffin (EC) cells in the duodenum of patients with coeliac disease and could also be directly related to described abnormalities of 5-HT metabolism in this disease.

Mode of action of antirheumatic drugs.

The concentrations of free and protein-bound L-tryptophan were measured in sera from normal subjects, patients with rheumatoid arthritis, pregnant women, and patients with jaundice. In the patients with rheumatoid arthritis receiving treatment with one or more antirheumatic drugs the percentage of the amino-acid bound to the circulating proteins was significantly depressed and in one patient returned to normal when therapy was stopped. Pregnancy and jaundice were also associated with raised free tryptophan and decreased bound tryptophan concentrations and bilirubin displaced the amino-acid from its binding sites on human serum proteins in vitro. It is suggested the behaviour of tryptophan mimics that of certain peptides which protect susceptible tissues against chronic inflammatory insults.