PURSE 2000

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Evaluation of Salmonella test method of Sri Lanka Standard Institute
(University of Peradeniya, 2000-12-16) Chandrasekara, R. A. N.; Jayasinghe, S.; Silva, I.
This study was conducted to evaluate the microbiological test method of Sri Lanka Standards Institution to detect Salmonella in foods. The SLS method was compared with the method published by Food and Agriculture Organization for detection of Salmonella by applying it to several food items. Black pepper. cinnamon, cardamom, cloves, and milk powder were artificially contaminated with Salmonella serotype H culture and uninoculated eggs were used for the study. A control test was carried out without adding the inoculum. Method of preparation of the food samples for isolation of Salmonella and the pre-enrichment media used. are specific for each food to be tested in the FAO method. However. SLS method employs the same preparatory procedure and the pre-enrichment media for almost all foods. Both methods gave positive reactions for artificially inoculated black pepper. cardamom. and milk powder. In the tests carried out for cloves and cinnamon by SLS method no positive reactions were observed whereas FAD method was able to identity the serotype H in these two spices. The anti-microbial substances in cloves and cinnamon appear to inhibit the growth of Salmonella by SLS method. In the fresh egg sample that was tested by the SLS method colonies were observed only in XLD agar. but not in Brilliant Green agar. These discrepancies observed for the test results for Salmonella leave room to suspect the applicability of the SLS method to foods.
Assessment of contamination of milk at diffrent stages of collection
(University of Peradeniya, 2000-12-16) Hathurusinghe, M. H.; Horadagoda, A.
Good quality milk in relation to composition and hygiene is a basic requirement to process the 'ready to drink' milk which is presently in great demand. Inevitably this market trend has stimulated milk-procuring agencies to examine milk for both composition and quality of milk at the various stages in the collection chain. A very large proportion of milk in Sri Lanka is produced by small holder dairy farmers where clean milk drawn directly from the udder is likely to be contaminated before it reaches a processing plant. Polluted water. unclean receptacles. long transit time with increased environmental temperatures. are some of the potential causes for increased bacterial counts in milk which reflect contamination. The purpose of this study was to identify the amount of contamination of milk at the different stages of collection and the influence of preservatives in reducing such contantination. The study was conducted among .to dairy farmers in three villages around Kandy. The fanners were visited three times during a period of six months. In the first visit. a sample of milk was collected to determine the degree of contarrtination. At the second visit a sample was collected for the California mastitis test (CMT) and the third visit was made to create an awareness of the importance of clean milk production. Ten per cent of sample drawn from the udder was positive for Methylene-Blue dye Reduction test (MBRT) after one hour. In contrast. 15% of milk samples collected from the bucket and 50% of the samples collected at the Milk Collecting Centers were found to be positive for MBRT after one hour. and by the end of the third hour all the collecting center samples were found to be positive. It was observed that polluted water and general unhygienic conditions were the main contributors to contamination of milk. Among the samples collected from the three villages, the management practices in one village was very poor. In this village even the samples collected directly from the udder were found to be heavily contaminated and 77% of them gave a positive reaction to the CMT. The addition of hydrogen peroxide was found to reduce the bacterial counts indicating that it is a useful preservative. The third visit helped to educate fanners on cleaner milk production resulting in a better price for their milk.
Investigating the possibilities
(University of Peradeniya, 2000-12-16) Padmasiri, S. I.
Prawn-shell derivatives extracted in the laboratory in two different methods were tested for their turbidity removal efficiency and pH dependency and the results were compared with those of alum and commercially available chitosan. One method gave a product which behaved similar to commercial chitosan in turbidity removal efficiency. It was discovered that the diluted supernatant also showed very high turbidity removal capabilities.
Bone formation and remodeling pattern in the mandible
(University of Peradeniya, Peradeniya, 2000-12-16) Arambaawtta, A. K. S.; Peiris, H. R. D.; Nanayakkara, D.
The development of the mandible occurs mainly by intramembranous ossification. However, its subsequent growth is brought about by the secondary cartilages that appear in the heads of the condyles. The present study was carried out to identify the bone formation and remodeling pattern in the mandible, and to establish the rate of bone formation at different sites in the mandible. Five male and five female Sprague Dawley rats receiving a normal diet were mated. From the day of mating, a bone marker, Calcein (flurescein methylene iminodiacetic acid- 30mglkg body weight), was injected intraperitoneally to the female rats at weekly intervals. This was continued on the new born rats up to seven weeks and the rats were sacrificed. Ground sections were prepared from the condyle and the base of the mandible. The observations under fluorescent microscopy revealed that the pattern of bone formation differed in the condyle and the base of the mandible. Clear fluorescent lines arranged in an organized manner were seen in the base. This arrangement was absent in the condyle and the fluorescent material was deposited in a random manner. In the growth cartilage of the condyle the proliferating cartilage cells are not arranged in columns as in the growth cartilage of a long bone. Therefore, the growth at the condylar head is multidirectional and fluorescent lines are not seen. The distance between fluorescent lines were measured using a calibrated ocular grid at the buccal alveolar bone, lingual alveolar bone, and the basal bone of the mandible. The mean values of bone formation obtained for these sites were 10.00 ± 9.16 11m, 42.8S± 00 11mand 2186± 10.39 11mrespectively. 195
Interactions among bees, wasps and some agricultural crop adjacent to the secondary forest at Gannoruwa
(University of Peradeniya, 2000-12-16) Karunaratne, W. A. I. P.; Gunatilleke, C. V. S.; Gunatilake, I. A. U. N.
Bees and wasps are economicaly imporatant insects as pollinators and predators. Decline of these insects is of global concern because of its impact on agricultural productivity, biological control of pests, and genetic diversity. This decline has been attributed to reduction in their natural habitats and the heavy use of insecticides. In this study the diversity of bees, their nesting sites, and activities on 37 agricultural crop species cultivated in the research fields at Gannoruwa, were examined in order to identify the specific pollinators of the crop species. Weed species and plant species found in the adjacent secondary forests were surveyed to acess its role in maintaing the populations of beneficial insects. Pollen found in the scopa (pollen carrying hairs) of bees were examined to recognize their true foraging plants. Xylocopa colonies were found nesting in wooden logs close to the cultivated lands while Ceratina sp. nested in rose stems. Colonies of social bees were not in the vicinity. Sweep netting off the vegetation caught 21 species of bees belonging to 11 (':') genera and four families of which Apis cerana. A ..florea and Trigona iridipennis were the most frequent visitors. Of the agricultural crop species surveyed Ipomoea batatas, So/anum melongena, Cucumis sativus, Persea americana and Luffa sp. were mostly foraged by bees for collecting pollen and/or nectarHedyotis and Tagetes were among the non-agricultural species frequently foraged by the bees.A number of polinators appear to be generalists visiting both agricultural and non-agricultural plant species suggesting the importance of the latter in maintaining the populations of pollinators especially during the lean periods resulting from the harvesting of annual crops at the end of their growing season.
An experimental cryptosporidium infection in mice and goat kids
(University of Peradeniya, 2000-12-16) Noordeen, F.; Horadagoda, N. U.; Faizal, A. C. M.
Cryptosporidiuni parvum, a zoonotic protozoan parasite of mammals. occurs throughout the world. Following infection, it multiplies within the microvilli of the enterocytes and produces pathological changes associated with clinical signs in susceptible hosts. Studies on experimental Cryptosporidium infections in various species reveal that the infectivity varies with the host species and the strain of the parasite. This paper describes the infectivity. pattern of oocyst shedding. and the morphological changes in the intestine following an experimental Cryptosporidium infection in goat kids. Crvptosporidiuni oocysts, isolated from adult asymptomatic goats. were identified as C parvuni by Polymerase Chain Reaction. Two. -l-day-old goat kids were infected orally' with C pan'IIJII oocysts (l05 oocysts in 10 ml phosphate buffered salinelkid) and an age-matched goat kid given an equal volume of phosphate buffered saline (PBS) by the same route served as a control. In addition, eight I-week-old mice were infected orally (103 oocysts/mouse) for comparative purposes. Crvptosporidium oocysts were detected in the feces of one infected kid on 3 days post inoculation (dpi) whereas in the other 6 dpi, The faecal oocyst counts gradually increased and the peak counts in both kids were 2 x 10° g'' (on 12 dpi) and 3.2 x 106 s" (on l-l dpi). The increase in faecal oocyst output coincided with diarrhoea in an infected kid from 10 to 17 dpi. Although. the oocyst excretion declined gradually after the peak. both infected kids excreted oocysts until euthanized on 20 and 22 dpi, Light and scanning electron microscopic investigations of the ileum revealed the developmental stages of the parasite within the brush border of the enterocytes, infiltration of neutrophils and mononuclear cells into the lamina propria, and atrophy. stunting and fusion of villi, All experimental mice excreted oocysts from 3 dpi, and -l infected mice continued to excrete oocysts until -l2 dpi. Thus, the experimental infection in goat kids resembled the natural disease in terms of oocyst excretion, clinical signs. and intestinal pathology. The ability of oocysts excreted by asymptomatic goats to infect goat kids and mice is likely to have a major impact on the epidemiology of cryptosporidiosis in livestock and man
Lymphoid leukosis in chicken : a case report
(University of Peradeniya, 2000-12-16) Ekanayake, S.; Horadagoda, N.U.; Fernando, G.K.C.N.; Mutucumarana, R.K.; Menike, K.A.G.B.
Lymphoid Leukosis (LL) is a lymphoproliferative disease resulting in visceral lymphomas in chicken caused by the Avian Leukosis Virus (AL V), and is transmitted vertically through the egg and horizontally by saliva and faeces. Lymphoid Leukosis is not clinically manifested in most flocks but varying non-specific symptoms like diminished appetite, severe emaciation, decrease or cessation of egg production, greenish diarrhoea, pale and shrunken comb, and sporadic death patterns have been observed. Generally, the birds older than 16 weeks are affected, and in most cases, the disease occurs following the onset of sexual maturity, causing heavy losses to the farmer. Lymphomas develops mostly in the liver and bursa of Fabricius, and to a lesser extent in the kidneys, spleen, ovaries, and bone marrow. In addition, ALV causes immunosuppression and also exposes the birds to other secondary infections like Chronic Respiratory Disease and Colibacillosis. A bird from a 26 week-old commercial layer flock was presented for diagnosis. A history of diminished appetite, stunted growth, severe emaciation, drop in egg production, sudden onset of paralysis, greenish diarrhoea, and sporadic death patterns were observed in the farm. Post mortem examination revealed the presence of several smooth yellowish- white neoplastic growths ranging from 0.2 - 2.5 ern in diameter and distinct borders in the liver, and also with enlarged bursa of Fabricius This extensive growth also resulted in compression and displacement of the normal tissues of the liver and the bursa of Fabricius. On a cut surface, the tumours appeared round with clear demarcation from normal tissues. Histologically, the tumours showed sheets of large immature lymphoblasts with little or no pleomorphism. Based on history, clinical picture, post mortem findings, and histopathology, the case was diagnosed as a diffused type of Lymphoid Leukosis. The farmer was advised to cull the entire flock and re-populate the farm with chicks obtained from ALV free flocks.
A study of the musical poetical forms and their contribution to the emotional expressions in the sokari drama
(University of Peradeniya, 2000-12-16) Seneheweera, L
Kolam, Nadagam. and the Sokari have been established as the folk drama in Sri Lanka. Kolam is a kind of a dramatic pcrfonnance. which survives today chiefly in coastal townships in South in Sri Lanka. particularly in Ambalangoda and Bentara. Nadagamas have been popular mostly in villages and townships along the western coast. from Chilaw in the north right down to places like Tangalle in the South. The Sokari is a folk ritual drama with much dramatic entertainment. confined to the Uda Rata and the Vanniya. Presently it is performed in the villages around Kandy. Traditions of Sokari performed at Uda Dumbara. Matale. Konakallagala. Vehigala arc well known, This ritual play in many of its tradition is performed to get the blessings of the goddess Paththini, However. in some tradition Kataragama with that part is emphasized: the story enumerates how Guruhamy and Sokari after their marriage came to Sri Lanka from South India to visit the famous devale of Kataragarna in order to get the blessings of that god to beget a child. The story is dramatically presented by players who resort to mime. dance and stylized movements as a backup for the normal prose and verse dialogue. In addition. there is much variation in poetical forms. although it may seem monotonous for a non-initiate. The play is lyrical and consists of a large number of verses. These could be divided into two categories of metrical and non-metrical composition, both of which could again be subdivided into measured and unmeasured forms: a large number of meters including Samudurugos. yagi. so on. Furthermore. it uses a large number of poetical forms such as sivupada. gi. sahali. as well as musical forms of rhythm. melody. and tempo. One could sum up that Sokan play is based on the genuine folk. poetical. and musical traditions of the upcountry tradition of Sri Lanka. The aim of the present research is to highlight this basic musical tradition,
Study of callus formation and regeneration of selected rice varieties and transfer of sytheticcry1 Gene rice callus
(University of Peradeniya, 2000-12-16) Wickramaratne, N. A. A. D.; Bandara, J. M. R. S.
Rice (Oryza sativa. L) is one of the most important food crop of the world serving as a major staple food crop for about 3 billion people In developing countries, 35%.55% of the potential yield of rice is lost mainly due to pest and diseases. In South and Southeast Asia, the average yield lost due to insect pest is 18.5%. Mordern methods of important include gene transfer to obtain pest resistant varieties. Tissue culture is a principal tool in gene transformation. In this study callus formation and regeneration of selected rice varieties Bg300, Bg304. Bg380. Bg352, Bg350 & IR8 were examined. Seeds were cultured on R2 medium with two 2. 4-D levels (I mg/l and 2 mg/l). Callus formation percentage was observed after 2 weeks of culturing. calli colour was observed at first subculturing and size was also measured prior to transfer to the regeneration medium Rice calli (Bg352) were co-cultivated with Agerobateriurn.' . bi C\\rBI\ !1()! ith heti I strain C58 carrying recom mant vector p .. . . Wit synt etrc cry gene. Transformation efficiency was checked by the GUS assay. Bg352 was the best in callus formation with favourable colour and favourable size. It is also the quickest to respond bv becoming green when transferred to regeneration medium, , f l 'I'd II' GL'S" T DN'A f 'h C.\.\fB1.\ Fifty three percent 0 t ie co-cu tivate ca I were I positive - 1 part 0 t e p 1.101has integrated successfullv with a genome of Bg352.
The resident birds of the Peradeniya University Campus, Sri Lanka
(University of Peradeniya, 2000-12-16) Wijesundara, W. M. C. S.; Santiapillai, C.
The campus of the University of Peradeniya, situated in the hill country of Sri Lanka, is one of the areas of high avifaunal diversity in the island. Of the 231 species of resident birds that have been recorded from the island, more than 80 have been observed in the Campus. In the present study that was conducted from April to October 1999, it was found that at least 67 species were present, excluding the nocturnal species. This amounts to 29% of the total number of residents in Sri Lanka. Weekly roadside counts of birds along a fixed route transect passing through the main habitat types in the campus (e.g. woodland, grassland, home garden, and pine forest) indicate that the commonest birds in the campus are the Common Mynah (Acridotheres tristisi, Black Crow (Corvus macrorhynchosi, Common Babbler (Turdotdes affinis), White-rumped Swift (Apus cffinisi, and the Spotted Dove iStreptopelia chinensisy. It is interesting to note that despite the common perception that the Black Crow is the commonest bird in the campus, it is in fact second to the Common Mynah The presence of the Red-wattled Lapwing iVanellus indicuss and the Indian Roller (Coracias benghalensisi in the campus is significant. These two species, which were typical of the Low Country Dry Zone of Sri Lanka only a few decades ago, have now established in the lower hills of the island, including the University Campus. Birds of prey are good indicators of ecological richness and species richness of an area. Their occurrence carries the implications of a larger ecological community. They are at the top of the food chains, and are vulnerable to the fluctuations of their prey species. The study shows that the campus is well represented by both nocturnal as well as diurnal species of predatory birds. The most commonly observed species are the Crested Serpent Eagle (Spilomis cheela) and the Shikra (Accipiter badiusi. The Collared Scops Owl tOtns bakkamoenai, though not often seen in the daytime given its nocturnal habits, is nevertheless common. The campus also supports a number of species that are endemic to Sri Lanka, of which the two most common species are the Sri Lanka Lorikeet iLoriculus beryllinus) and the Yellow-fronted Barbet (Megalaima flavifronsv. The species richness and species evenness indices (Shannon Index and Shannon Evenness Index) indicate that the woodlands have the highest number of avian species (54 species, with a Shannon Index of3.24), while grasslands though slightly low in avian species richness (52), are more diverse (with a Shannon Index of 3.26). The dominance indices (Berger-Parker Index and its reciprocal form) show that grasslands have the lowest dominance (0 II) and hence the highest evenness (886) (and so more diverse) According to the similarity indices (Sorenson Quantitative), the woodland and grassland habitats are the most similar (0.99) in terms of avian species richness. The study shows those natural forests, or forests with indigenous plant species, are the habitats with very high bird diversity, whereas plantations of exotics such as Pine (Pill us caribaeai are extremely poor habitats for birds. This study underlines the importance of maintaining natural vegetation in the conservation of birds and other species of wildlife.
The incidence of hypothyroidism following radio-active iodine therapy for hyperthyroidism
(University of Peradeniya, 2000-12-16) Hettiarachchi, H. K.; Gunawardhana, S.; Gunaweera, P.
A retrospective study was conducted with the objective of finding out the incidence of hypothyroidism following 1311 treatment for hyperthyroid patients. All hyperthyroid patients treated with 1311 at the Nuclear Medicine Unit, Faculty of Medicine, University of Peradeniya during the period of 01.01.1997 to 28.02.1999 were selected from records at the unit. Data from 60 patients who were given radioactive iodine (with either T4 > 20 ug Idl or TSH < 0.3 mull) were analysed. Patients who developed blood concentrations of TSH > 20 mull were selected as being hypothyroid. Eighteen patients out of 60 (30%) had developed hypothyroidism during the selected period which is more than double the value shown among the western countries (6-15%)
Managing shoot borers by using acacia auriculiformis as a nurse crop for establishing mahogany seedlings
(University of Peradeniya, 2000-12-16) Mahroof, R. M.; Edirisinghe, J. P.; Hauxwell, C
TIle main factor. which has limited cultivation of mahogany. Swietenia macrophylla, King (Meliaceae: Swietenoideae) is damage by shoot borers (Hypsipvlo spp.). Attack results in destruction of the apical shoot, causing branching of the tree. and significantly reducing the economic value of the timber. Although shoot borers have been intensively investigated no consistently effective control methods currently exist. However, some observations suggested that overhead shade provided by a nurse crop during early growing phase of mahogany seedlings might reduce the attack. Yet much of the information available is anecdotal. Although shade reduces attack by shoot borer. mahogany being a light demander. shade also may reduce the growth of seedlings. Hence a study was designed to assess the effect of different light availability on survival, growth and attack by shoot borers under different light conditions. This study was done from 1997-99 at three sites. two from Rambukkana and one from Mirigama under a nurse crop .-Icacia auriculiformis A. Cunn. Ex Benth. (Miruosaceae). Each site composed of three plots with different canopy openings of high. medium and low shade obtained by pruning of Acacia trees. Within pruned area (5 m x 5 m), 18 mahogany seedlings of similar origin. age and height were planted. TIle Photosynthetically Active Radiation (PAR) reaching each plot was measured using a data logger with a PAR sensor. Pattern of flushing and growth of mahogany seedlings were recorded monthly. Number of shoot borer attacks per plant was recorded l~ months after planting. Relative PAR values in the three sites varied from 21.6 ± U % in the higher shade gap to 93.1 ± 3.3 % in tlle lower shade gap. Seedling survival a year after planting did not show significant differences between light regimes. Under low shade. seedling height was 57.~ % greater than under high shade. and was highly significant in ANOYA (d.f.=2. P=0.00(1). TIle root collar diameter under low shade was U ± 0.09 em, while that under high shade was 0.8 ± 0.04 cm (d.f=2, P=O.OOUI).Seasonal variation in shoot phenology showed a similar trend in all shade regimes. with increased flushing observed during the rainy period, but shoot remained dormant during the dry spell. Number of attacks per plant in low shade plot was 112 times higher than under high shade (d.f=2. P=O.OOOI).Observations of this study show that high shade (20-30 % PAR) reduces growth of mahogany even though it might reduce attack by shoot borer and the best rapprochement to manage shoot borer problem while achieving reasonably good growth would be medium shade conditions (~5-50 % PAR).
Qualitative effect of the swine industry on the environment in the Mahara- Kadawatha veterinary range
(University of Peradeniya, 2000-12-16) Nissanka, R. G. C.
In Sri Lanka, the present pig population is approximately 80,300. Pig farming is beginning to make an important contribution to the livestock sector. Among the Agricultural Livestock enterprises, swine management requires a great deal of attention as the pig industry can adversely affect the environment. The main objective of this project was to identify the gross/qualitative effects caused by the pig industry on the environment in the Mahara-Kadawatha Veterinary Range. The study was based primarily on the data collected during the period, November 1999 to May 2000, using a questionnaire given to 27 piggery owners selected randomly from the Mahara-Kadawatha Veterinary Range. A second questionnaire was given to at least one neighbour of each farm, and the observations made on each of these farms and its surroundings were noted at each visit. The data were analyzed manually to determine the percentage occurrence of the specified conditions and the results are presented in the form of bar and pie charts. The major environmental problem caused was the unpleasant odour generated from pig excreta, swill, and wastewater. Although all the farmers used swill as a feed, it was not disposed properly and this was found to be a major contributory factor in environment pollution. All the farmers around the Muthurajawela swamp were found to dump their piggery waste into the swamp. From the survey done, it was clearly shown that there was considerable amount of environmental pollution taking place due to the pig industry in the Mahara-Kadawatha Veterinary Range. Farmers should always maintain the standard buffer zone. Swill should not be given in excess amounts and should not be retained for more than 24 hours. The buildings should be : eaned at least twice a day and there should be a proper waste disposal system. The farmers ould be educated about the conservation of their living environment and there should be an ive authority to check and regulate the necessary standards.
An anlysis of legislation for protection of the environment and its impact on health
(University of Peradeniya, 2000-12-16) Gooneratne, I.; Gooneratne, N.
Health services in Sri Lanka are provided mainly through the Ministry of Health, local authorities, and private sector, but at present it is the government that is responsible to render public health! community health services. It is a known fact that the environment has an impact on health. For many years environmental health has been a legal responsibility of national and provincial health authorities, but the control of environmental factors affecting health has long been shared by other ministries, agencies and agents. The purpose of this study was to analyze the legislation for protection of the environment and its impact on health. Among the laws that have been enacted to protect the environment, quarantine and prevention of diseases ordinance, housing and town improvement ordinance, town and country planning ordinance, food act, cosmetic and drugs act, control of pesticides act, national environmental act, medical ordinance, urban development authority act, the nuisance act. central environmental authority law, and constitution of Sri Lanka and its amendments were shown to have an impact on health
Monocolonal antibody based flow cytometric method for the detection of enterotoxigenic clostridium perfringens
(University of Peradeniya, 2000-12-16) Piyankarage, R. H.; Uemura, T.
An assay combining flow cytometry (FCM) and C. perfringens enterotoxin (CPE) specific monoclonal antibody ( MAb ) was developed for the detection of enterotoxigenic Clostridium perfringens. Biotin conjugated anti-CPE MAb and fluorescent avidin was used to study the sporangia I cells of C. perfringens, which were collected from 6-8 hour sporulation cultures. Using this assay. eight strains of C. perfringens which possessed the enterotoxin gene and belonged to distinct Hobb s types were analyzed. FCM profiles of C. perfringens sporangia harvested from 6-8 hr sporulation cultures in Duncan and Strong (OS) medium revealed positive reaction for CPE. whereas vegetative cells and heat-treated sporangia of the same strain produced a negative reaction. Among eight different strains. high CPE producing strains showed high peak channel number and poor CPE producers demonstrated low peak channel numbers under FCM analysis. The flow cytometric method was found to be rapid, specific. accurate and reproducible. and can be used effectively in the detection of enterotoxigenic C. perfringens. Furthermore it might be of immense use in the diagnosis of food poisoning outbreaks.
Effect of dexamethasone on the metabolism of testosterone in human gingival fibroblasts
(University of Peradeniya, 2000-12-16) Tilakaratne, A.; Soory, M.
Dexamethasone has been known to have synergistic interactions with growth factors to induce proliferation of human diploid periodontal ligament and gingival fibroblasts. It can also stimulate the formation of new cementum and alveolar bone. The anabolic effects of androgens especially 5a-dihydrotestosterone (DHT) are well established. The aim of this investigation was to study the effects of dexamethasone (Dex) on the metabolism of testosterone in human gingival fibroblasts (HGF). Confluent monolayer cultures of HGF of 5th_9'h passage derived from chronically inflamed gingival tissues were established in Eagle's Minimum Essential medium. Duplicate incubations were performed with 14C-testosterone (l4C-T) as substrate and serial concentrations of Dex ranging from 0.5-50 ug/ml for 24 hours. At the end of the incubation period. the steroid metabolites were ana lysed and quantified using a radioisotope scanner. Most of the lower concentrations of Dex showed a stimulatory effect on DHT synthesis from 14C-T. with a maximum increase of 44% at 1.0 ug/ml, decreasing to 14% at 10 ug/ml and reaching control values at higher concentrations. The increases in DHT in response to the lower concentrations of Dex (ranging from 0.5-8.0 ug/ml) were statistically significant (n=6: p<0.05: ANOYA). Synthesis of the other major metabolite. -l-andrcstenedione from 14C-T showed 20- 36% increases in response to the range of 0.5-5.0 ug/ml of De x (n=6: p<0.05: ANOYA). Dexamethasone at lower concentrations could induce the metabolism of testosterone in cultured human gingival fibroblasts resulting in the formation of anabolic metabolites. This could enhance connective tissue and bone matrix synthesis and play an important role in tissue regeneration in inflammatory periodontal lesions.
Development of "EdRex" a computer pakage for the automation of examination procedures in the Faculty of Agriculture
(University of Peradeniya, 2000-12-16) Wickramasuriya, H. V. A.; Basnayake, M.; Angammana, A.
The efficient functioning of the Examination Unit is essential for the smooth administration of a university faculty. Therefore. the objective was to develop a software package for the Examination Unit. It was an in-house development through End User Computing at negligible financial cost. The package was developed as an application of Access' with Visual Basic'. Product development took two years during which time a Beta version and two other versions were rigorously tested. At present the product enables instantaneous registration of a full batch. of compulsory courses, and easy registration of optional courses. the generation of class lists. class attendance sheets. admission cards, examination attendance sheets. mark sheets. results sheets. and transcripts. Response time for each process is less than 2 seconds. enabling a very significant increase in the efficiency of the Unit. Some security features were provided. User support and training "ere provided. This package is currently being used in the Faculty and the response received has been extremely positive.
Low-cost laborartory scale laterite-based filter for removal of industrially used colouring substances
(University of Peradeniya, 2000-12-16) Perera, S.; Priyantha, N.
Water soluble dyes, such as azo dyes, anthraquinone, formazan, and pthalocyanine are extensively used in textile, paper, and ceramic industries. Physico-chemical methods, such as adsorption, coagulation and precipitation, filtration, and oxidation have been used for the treatment of such co loured effluents. Nevertheless, surface water may become coloured when highly colored industrial effluents are discharged without proper treatment. Laterite, among many natural substances such as termite mount-clay, saw-dust, kaolinite, and dolomite, offers a significant ability for removal of co loured substances, in particular, industrial dyes used in textile and synthetic fibre industries. The efficiency of the removal process strongly depends on conditions such as solution pH, amount of adsorbent, and size of laterite particles. Treatment of 100 cnr' of co loured dye solutions within the concentration range of 0.1 rng/drrr' to 10 mg/drrr' with wet laterite, under optimized conditions, results in the maximum removal efficiency of about 90-92%. Adsorption isotherm and recovery studies suggest that the removal occurs through ion exchange in conjunction with surface adsorption. More importantly, laterite-packed columns are able to decrease the Chemical Oxygen Demand (COD) by 60%. Although the percent removal is higher for the laboratory prepared solutions, it is little less for industrial effluents due to interferent effects. A filter based on laterite, developed by extending the above stated methodology, also shows excellent results. As such filters simulate real situation, the proposed methodology would open an alternative avenue, which is environmentally friendly and cost-effective, for the treatment of coloured industrial effluents.
Udas: an inquiry into the South Asian state of mind
(University of Peradeniya, 2000-12-16) Goonasekera, S.
A state of the mind known as udas is widespread in Rajasthan, India. Although accurate statistical infonnation regarding its distribution is hard to obtain. linguistic data indicate its prevalence throughout the South Asian cultural area from ancient times. In Rajasthan, in tile central regions around Jaipur, Bikaner and Jodhpur, in tile region known as Marwar where I conducted my field research. This is a well-known phenomenon. Adults of every age seem to experience this condition of being. Field data show and lexicographic research confirms that there is a common definition for this state of mind. According to the common definition, udas refers to a heart heavy with sadness. dissatisfaction one feels about one' s lot in life and disquiet about tile nature of the world and how people live in it. What are the characteristics of individuals who experience udas? How do the Jains identify, classify, and evaluate them? What methods are available in tile local culture to deal with this condition? What methodological and philosophical issues render the Jain cultural constructions about this mental state incommensurable with the psychiatric constructions about it? I address these issues in my essay.
Insecticide resistance and the vectorial capacity of culex quinquefasciatus, the vector of filariasis
(University of Peradeniya, 2000-12-16) Karunaratne, S. H. P. P.; Hemingway, J.
Filariasis. caused by the nematode parasite Wuchereria bancrofti is endemic in Sri Lanka. The mosquito Culex quinquefasciatus is the vector of filariasis in Sri Lanka and other tropical countries. Control of this mosquito is mainly by organophosphorus insecticides. Resistance mechanism of Culex mosquitoes to organophosphorous insecticides is the elevation (increased quantities) of mosquito carboxylesterases and occurs in more than 80% of resistant Culex worldwide. Biochemical characterisation of these carboxylesterases. purified from C. quinquefasciatus from Colombo. Sri Lanka. revealed that they bind and inactivate organophosphorous insecticides very fast. Antiserum was raised against these esterases and respective genes were isolated. It was found that gene amplification was responsible for the increased production and the resistant insects have upto 80 copies of the gene. Electron- microscopic studies. using mosquito tissues and the antiserum. revealed that the enzymes in resistant insects are expressed at very high levels in the mosquito gut and sub-cuticular layer. As the parasites must pass through some of these tissues to complete their development. parasite survival and hence vectorial capacity can be affected by the insecticide resistance status of the insect. However, insecticide resistance is assumed to increase the likelihood of disease transmission by increasing the population size and allowing the mosquitoes to he longer in the presence of insecticides. This hypothesis was tested for the first time. Blood fed female C quinquefasciatus were collected from seven filariasis endemic areas in Sri Lanka. Mosquitoes were individually analysed for parasite loads by quantitative PCR and insecticide resistance by biochemical assay with para-nitrophenyl acetate (pNP A). Almost 80% of the mosquitoes were infected with W bancrofti. However. there was a strong negative correlation between esterase activity levels with pNP A and parasite RNA levels in all seven localities. Membrane feeding of the insecticide resistant and susceptible mosquito colonies with If'. bancrofti infected blood produced infective parasite larvae after twelve days in 76% of the susceptible. and none of the resistant females. Results suggest that elevated esterase activity affects the development of W bancrofti larvae which may be arrested in the gut cells of insecticide resistant. but not susceptible mosquitoes. Filarial worm infection of mosquitoes cause significant damage to the mosquito host. and high microfilaria infections result in insect mortality. The predominance of the elevated esterase-based resistance mechanism in field populations of r. quinquefasciatus may therefore be influenced by the dual roles of insecticide detoxication and reduction of microfilarial burdens.

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