Thallium sulphate inhibited microbial growth, with Bacillus megaterium KM more sensitive to the metal than Saccharomyces cerevisiae and Escherichia coli. Inhibition of B. megaterium KM and S. cerevisiae, but not of E. coli, was alleviated by increasing the potassium concentration of the medium; inhibition of respiration of S. cerevisiae, but not of E. coli, was similarly alleviated. Thallium was rapidly bound, presumably to cell surfaces, by S. cerevisiae and E. coli, and was progressively accumulated by energy-dependent transport systems (probably concerned primarily with potassium uptake) with both organisms. Thallium uptake kinetics suggested more than one transport system operated in yeast, possibly reflecting a multiplicity of potassium transport systems. Apparent Km and Ki values for competitive inhibition of thallium uptake by potassium indicated S. cerevisiae to have a higher affinity for thallium uptake than for potassium, while E. coli had a transport system with a higher affinity for potassium than for thallium. The likely systems for thallium transport are discussed. A mutant of E. coli with tenfold decreased sensitivity to thallium was isolated and apparently effected surface binding of thallium in amounts equivalent to the wild type organism, but showed no subsequent uptake and accumulation of the metal from buffer, even though it was able to accumulate potassium to normal intracellular concentrations during growth.

The influence of intraoperative lavage with various solutions was tested on the healing of experimental colonic anastomoses performed in the presence of obstruction. After 24 h of ligature obstruction to the pelvic colon, male Wistar rats (n = 108) underwent colonic resection and primary anastomosis, using lavage with one of four different fluids: saline, povidone-iodine, 10 per cent hypertonic glucose and short-chain fatty acids (SCFA). Controls had no lavage. The anastomotic segment was excised and studied after 3 or 6 days. At day 3, mean(s.d.) bursting pressure was significantly greater in animals receiving SCFA compared with controls (81.2(23.0) mmHg versus 34.8(34.0) mmHg). Mean(s.d.) bowel wall tension was higher in rats with SCFA (30.6(8.1) N/m x 10(-4) or hypertonic glucose (29.5(10.1) N/m x 10(-4) compared with controls (12.2(12.1) N/m x 10(-4). By day 6, the anastomosis was more resistant to intraluminal pressure in each lavage group; mean(s.d.) hydroxyproline concentration at the anastomosis was greater in rats with SCFA (12.4(1.5) micrograms/mg) or hypertonic glucose (11.6(2.9) micrograms/mg) than in controls (8.9(1.5) micrograms/mg). Anastomotic healing is improved by all types of intraoperative colonic lavage, particularly with SCFA and hypertonic glucose solutions.

SUMMARY The role of histamine in acid secretion is controversial. Improvements in the techniques of histamine assay allow a better assessment of the relationship of histamine to acid secretion. Patients with duodenal ulcers were studied to determine the mucosal histamine responses to pentagastrin stimulation to relate the appearance of histamine in the gastric juice to acid production during stimulation, and to detect changes in the plasma histamine concentration during pentagastrin stimulation. There was a mean 27% fall (range 0-60%) in mucosal histamine concentration after

Of the three main races of Singapore, Malays and Indians are less susceptible to gastric and colorectal carcinoma and peptic ulcer when compared with Chinese. Racial differences in dietary habits include a smaller amount of chilli consumed by the Chinese when compared with the other two races. Chilli may be expected to accelerate gastrointestinal transit and hence to inhibit colonic carcinogenesis, while its active ingredient capsaicin protects against experimental gastric mucosal injury. The effect of chilli consumption was studied in relation to: (i) gastrointestinal crypt cell production rate and nucleic acid content as indices of mucosal proliferation, which is related to the risk of development of gastrointestinal cancer and peptic ulcer; and (ii) azoxymethane-induced intestinal cancer. Sprague-Dawley rats (n = 102) received either standard powdered chow or chow supplemented with 100 or 200 mg of chilli powder daily for 1, 18 or 24 weeks. Gastric, small-bowel and colonic crypt cell production rates were studied at all three time periods, while mucosal DNA, RNA and protein contents were measured at 1 and 24 weeks. While crypt cell production rates were unaffected by chilli ingestion, mucosal contents of nucleic acid and protein were mostly increased in chilli-fed animals compared to controls, especially in the colon at 24 weeks. A further 99 rats received subcutaneous injections of either azoxymethane 15 mg/kg/week x 6 or sterile water and were randomized to the same three dietary groups for 26 weeks. The number, size and location of benign and malignant duodenal and colonic tumours were unaffected by chilli intake.(ABSTRACT TRUNCATED AT 250 WORDS)