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.

A Scale to Assess Severity in Organophosphorus Intoxication: POP Scale:

Abstract: We have developed a clinical scale to assess severity or organophosphorus (OP) intoxication. Five common clinical manifestations of OP poisoning have been selected as parameters, each to be assessed on a 3 point scale varying from 0-2. Poisoning can then be graded as mild (score 0-3), moderate (score 4-7) or severe (score 8-11) when the patient first presents. The scale was validated using two consecutive series of 173 patients with OP poisoning. Correlations between the scores obtained on admission and three outcome variables, namely, death, the need for ventilatory support and the dose of atropine required in the first 24 hours after admission were significant. We believe that this scale would assist in grading severity of OP intoxication at first contact and help in predicting possible outcome.

Canopy position affects the relationships between leaf respiration and associated traits in a tropical rainforest in Far North Queensland.

Abstract: We explored the impact of canopy position on leaf respiration (R) and associated traits in tree and shrub species growing in a lowland tropical rainforest in Far North Queensland, Australia. The range of traits quantified included: leaf R in darkness (R-D) and in the light (R-L; estimated using the Kok method); the temperature (T)-sensitivity of R-D; light-saturated photosynthesis (A(sat)); leaf dry mass per unit area (LMA); and concentrations of leaf nitrogen (N), phosphorus (P), soluble sugars and starch. We found that LMA, and area-based N, P, sugars and starch concentrations were all higher in sun-exposed/upper canopy leaves, compared with their shaded/lower canopy and deep-shade/understory counterparts; similarly, area-based rates of R-D, R-L and A(sat) (at 28aEuro...A degrees C) were all higher in the upper canopy leaves, indicating higher metabolic capacity in the upper canopy. The extent to which light inhibited R did not differ significantly between upper and lower canopy leaves, with the overall average inhibition being 32% across both canopy levels. Log-log R-D-A(sat) relationships differed between upper and lower canopy leaves, with upper canopy leaves exhibiting higher rates of R-D for a given A(sat) (both on an area and mass basis), as well as higher mass-based rates of R-D for a given [N] and [P]. Over the 25-45aEuro...A degrees C range, the T-sensitivity of R-D was similar in upper and lower canopy leaves, with both canopy positions exhibiting Q(10) values near 2.0 (i.e., doubling for every 10aEuro...A degrees C rise in T) and T-max values near 60aEuro...A degrees C (i.e., T where R-D reached maximal values). Thus, while rates of R-D at 28aEuro...A degrees C decreased with increasing depth in the canopy, the T-dependence of R-D remained constant; these findings have important implications for vegetation-climate models that seek to predict carbon fluxes between tropical lowland rainforests and the atmosphere.

Multispecies coexistence of trees in tropical forests: spatial signals of topographic niche differentiation increase with environmental heterogeneity

Abstract: Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed. We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatible with neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences. We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity.

Quantitative evaluation of tissue invasion by wild type, hyphal and SAP mutants of Candida albicans, and non-albicans Candida species in reconstituted human oral epithelium.

Abstract: Background: Oral candidiasis is a common problem in compromised patients. Although several non-albicans Candida species have emerged as pathogens the majority of candidal infections are caused by Candida albicans. Morphogenesis from the blastospore to filamentous phase, and production of secretory aspartyl proteinases (SAP) are two major virulence attributes of these opportunistic yeast. Histopathology of oral candidiasis is characterized by fungal invasion of the superficial epithelium although the invasive potentials of different Candida species vary. Computerized image analysis systems (IAS) utilizing immunohistochemistry have been successfully employed for quantification of such histopathological features. The purpose of this study was to evaluate quantitatively the in vitro invasive potential of C. albicans and its hyphal and SAP mutants, and five other non-albicans Candida species using a computerized IAS. Methods: In vitro human oral candidiasis was produced using five wild type and one reference C. albicans isolates, hyphal and SAP mutants of C. albicans SC 5314, and one wild type and one reference isolate each of C. tropicalis, C. dubliniensis, C. glabrata, C. parapsilosis and C. krusei in a reconstituted human oral epithelium (RHOE) model. The infected tissues were examined histologically at 12, 24 and 48 h. Invading fungal elements were visualized by periodic acid-Schiff (PAS) staining and quantitatively evaluated as a percentage of total tissue invasive area, using a computerized IAS. Results: All C. albicans isolates including hyphal mutant cph1/cph1 and SAP mutants; sap 1-3, sap 4-6 produced hyphae and differentially (P < 0.05) invaded the tissue over 48 h. The invasive potential of hyphal mutant cph1/cph1 and SAP mutants (sap 1-3, sap 4-6) were similar to the parent wild-type isolate at 12 h although after 24 h their invasion was dissimilar (P < 0.05). Non-albicans Candida species and hyphal mutants; efg1/efg1, efg1/efg1 cph1/cph1 were all non-invasive. Conclusions: RHOE model in combination with computerized image analysis permits for the first time, the assessment of invasive potential of Candida species in a quantitative manner. The differential tissue invasive patterns of various C. albicans isolates, their mutants and other Candida species are also described.