University of Peradeniya

About: University of Peradeniya is a education organization based out in Kandy, Sri Lanka. It is known for research contribution in the topics: Population & Poison control. The organization has 5970 authors who have published 7388 publications receiving 197002 citations.

The effect of tobacco smoking and of betel chewing with tobacco on the buccal mucosa: a cytomorphometric analysis.

Abstract: The effect of tobacco use on the buccal mucosa has been assessed by cytomorphometry. Cell and nuclear diameters (CD, ND) of exfoliated oral squames were measured in tobacco smokers (S), betel chewers with tobacco (C) and those with a combined habit (S+C). Non-users (NU) served as controls. The mean CD values in S, C, S+C and NU were: 50.8 (+/-0.47), 49.39 (+/-0.48), 49.12 (+/-0.47) and 51.87 (+/-0.76) microm, and the mean ND values were: 8.83 (+/-0.07), 8.61 (+/-0.08), 8.72 (+/-0.10) and 8.33 (-/+ 0.09) microm, respectively. The least significant difference procedure (LSD at P=0.05) showed a significant reduction for CD in C and S+C and an increase for ND in all three habit groups, compared to the controls. This study shows that the use of tobacco influences the cytomorphology of the normal buccal mucosa. Betel chewing with tobacco influences the ND and CD, while smoking influences only the ND.

Role of verocytotoxigenic Escherichia coli in cattle and buffalo calf diarrhoea

Abstract: 273 Strains of Escherichia coli isolated from diarrhoeic and healthy control cattle and buffalo calves in Sri Lanka, were tested for Verocytotoxin (VT) and for heat-stable (ST) and heat-labile (LT) enterotoxins. VT and ST toxigenic E. coli were significantly associated with diarrhoea, accounting for 28% and 18% of diarrhoeic episodes, respectively. LT toxigenic E. coli were not significantly associated with diarrhoea.

The cowpea aphid, Aphis craccivora, host plant odours and pheromones

Abstract: Olfactometer experiments were conducted with apterae and alatae of the cowpea aphid, Aphis craccivora, Koch (Hom.:Aphidoidea). The occurrence of density dependent related pheromones and odour response to their host plant Vigna unguiculata was studied. Apterae responded with positive anemotaxis to air passed over both small groups of apterae and alatae (≤10 individuals) but negatively to air that passed over a bigger group (≥20 individuals). Alatae responded in the same way to groups of apterae but were repelled by alatae independent of the size of the group applied as odour source in the olfactometer, except when exposed to air passing ten alatae feeding on cowpea leaves. This may be due to interaction between aphid pheromones and host plant odour. Both apterae and alatae showed a general attraction to green plants and were also able to distinguish between other host plants and cowpea, which was the original host of the aphid clone used in the experiments. When attacked by aphids, the cowpea plant responded with a temporal increase in attractivity that reached a maximum after 48 h and had disappeared after one week.