University of Colombo
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Item The effects of ischaemia on periphral myelinated nerve(University of Colombo: UC(MED)., 1974) WEERASURIYA, AItem Lankawe balapacharin vashayen thindu karana lada aya ema thathwayata pathweema udesa balapana lada hethu pilibanda wimarashanayak(University of Colombo: UC(CEN.)., 1979) PERERA, GPItem Analysis for lead in study materials of primary school children such as water colours, clays and crayons.(University of Colombo: UC(SCI)., 1979) DE MEL, LSKThe estimation of Lead in the samples of water colours, clays and crayons has been carried out using the Dithizone Proce Dure (5) the method adapted by the Sri Lanka standared committee for lead in water colours. The Sri Lanka standard specifies not more than 250 mg/kg of lead for the water colours and mo standared are prescribed for clays and crayona Total of forty one (41) samples of the three materials under study were analysed for their lead concentration and most of the samples had the lead contant within the standard specified for water couloursThe yellow colours of all the materials analysed excepting two makes of water colours, had lead concentration over the standard limit. One of the makes had all the colours with lead concentration lead than10mg/kg.Item Gatalu hasireem dakvana shisayan (Balapacharin) pilibandava colamba distrikaye balapachari sahathika pasalak asurin adhayanayak(University of Colombo: UC(CEN.)., 1979) SAMARASINGHE, SSItem The Search for the `adaptive enzymes' sucrose phosphorylase in sucrose utilizing bacteria(University of Colombo: UC(MED)., 1980) KANNANGARA, PNLeuconostoc species from coconut toddy and from cabbage and a Klebsiella species were grown in sucrose-phosphate medium. Klebsiella species had the fastest growth rate and reached the late log phase in 9 - 10 hours while the Leuconostoc sp. from cabbage took 12 - 14 hours and that from toddy 2 and half - 3 days. They all used sucrose as the sole carbon source with the help of the enzyme invertase and not sucrose phosphorylase. The invertase from all three species were found in the 13,000g supernatant and they were not membrane bound. The activity of invertase in the Leuconostoc species (toddy) Klebsiella sp. and Leuconostoc sp. (cabbage) were 8.06, 45.0 and 77.7 units per mg protein respectively. The invertase activity was lost when the crude enzyme preparation was stored at 00C in half saturated neutral ammonium sulphate solution for 2 to 3 days. The invertase appears to be a metallo anzyme and it is 85 percent inhibited by 5 X 10 -2 M EDTA in Klebsiella and 67 percent inhibited in the sp. of Leuconostoc from cabbage. The presence of sucrose phosphorylase could not be demonstrated in all three species of bacteria by any one of the standard assay methods used. Removal of invertase by ammonium sulphate precipitation or the inhibition of invertases and phosphatases (both acid and alkaline) by the addition of sodium fluoride, tartarate, formaldehyde and EDTA also indicated the absence of sucrose phosphorylase in these bacterial species.Item Purification and study of the kinetic of alpha galacto idase from coconut kernel(University of Colombo: UC(MED)., 1980) MATHEW, CPDWTwo Alpha Galactosidase isoenzymes have been isolated from coconut kernel and characterized using sephadex column chromotography. The elution had been done using Mcilvaine buffer (pH 5.5) containing KC1 (Balasubramanium et al 1974). The purity of these enzymes have not been tested. In this study Alpha Galactosidase was eluted from the sephadex column using Mcllvaine bufer (pH 5.5) without KC1. All the enzyme was eluted in the low molecular isoenzyme form. Recovery from the coloumn was 23.6 percent of the original extract, the purity of the enzyme increasing 171 fold. The enzyme thus obtained was further purified by concentration using ultrfiltration and ultracentrifugation. At this stage 11.5 percent of the original extract was recovered while the purity increased up to 512 fold. This enzyme preparation when tested by polyacrylamide gel electrophoresis showed a single protein band which corresponded to the fluorecent band obtained by the action of Alpha Galactosidase on umbelliferyl Alpha D galactopyranoside. On cellulose acetate paper electrophoresis a single enzyme activity band was obtained. As the protein concentration was too low, the corresponding protein band could not be detected. Molecular weight of the purified enzyme was 18330. The enzyme was inhibited by a substrate concentration of para nitrophenyl Alpha D galactopyranoside of 6 X 10-4M. For the above substrate Km was 2.5 X 10-4M and Vmax was 25 uMol/min/mg. of protein. The enzyme is stable upto 450C. Activation energy was 6.83 Kcal per mole. Enzyme activity showed a broad pH optimum from 2.5 to 6 with a peak at pH 5.5. Enzyme was noncompetitively inhibited by mercuric ions and was competitively inhibited by D galactose.Item Antibiotic principles from Sri Lankan marine algae and chemical investigation of Caulerpa racemosa(University of Colombo: UC(CEN.)., 1980) THARMATHEVA, SJItem Environmental evaluation of lead, sulphur dioxide and levels at selected sites in Colombo.(University of Colombo: UC(SCI)., 1981) GODAVITARANE, APSItem Environmental and biological lead absorption.(University of Colombo: UC(SCI)., 1981) NAGARAJAH, SItem A Brief survey of the extent of the use of permitted synthetic colouring matter in sweets sold in the Colombo Area(University of Colombo: UC(SCI)., 1981) SINNATAMBY, RItem Studies on Some medicinal plants(University of Colombo: UC., 1981) DE SILVA, ULLItem Effect of noise in hearing in powerloom factories(University of Colombo: UC(SCI)., 1981) SUNTHARALINGAM, DItem Buddhi sanwardanaya pilibanda Piyaje ge niyaya lankawe lamun sambandhayen kotharam durata anukulathavayak dakvaida?(University of Colombo: UC(ML)., 1981) ELISEBETH, JMDMEItem Sri Lankawe vishva vidyala shishayan thula pawathna kansavan pilibanda adhayanayak ha upadeshaka sevaya saha marggopadeshaya sandha in lada haki prayojana(University of Colombo: UC(CEN.)., 1981) RANAWAKA, DSItem Effect of noise on hearing levels of secondary school students(University of Colombo: UC(SCI)., 1982) SUBASINGHE, SItem Some observations on the oral hypoglycaemic activity of aegle marmelos(University of Colombo: UC(MED)., 1982) SINNADORAI, GThe oral hypoglycaemic activity of aqueous extract of the root bark of Aegle Marmelos (Family Rutaceae) was investigated using Sprague-Dawley rats. The parameters used as indices of oral phpoglycaemic activity were (a) its effect on fasting blood glucose concentration and (b) glucose tolerance curve. The extract showed a significant reduction (approximately 48 nper cent) of fasting blood sugar concentration when compared to control animals. The maximum hypoglycaemic activity was observed 3 hours after administration of the extract and the effect seems to last for more than five hours. The extract also showed significant enhancement of the ability to tolerate an external glucose load. The peak level of blood glucose concentration following the administration of the drug was decreased by 50 percet. Dose response studies carried out indicated that maximum hypoglycaemic response was associated with a dose of 1 ml/100 gms body weight. The minimum hypoglycaemic response was observed with a dosage of 0,25 ml/100 gms body weight. The investigation of the effect of storage (at room temperature) of the extract on biological activity revealed a gradual decline of the hypoglycaemic activity with storage. This gradual loss of bilogical activity may be due to bacterial action or some other mechanism. Preliminary experiments condicted to evaluate any beneficiary effects of the extract on streptozotocin-induced experimental diabetes, revealed no difference between the drug treated diabetic animals and untreated diabetic animals. However, these studies are not sufficient to arrive at any definite conclusion. The effect of the drug on liver insulinase activity was also studied. Here too the experiments carried out were not sufficient to gain any insight on the effect of the drug on insulinase activity.Item Isolation and purification of sucrose phosphorylase from acetobactor xylinum and synthesis of sucrose by sucrose phosphorylase(University of Colombo: UC(MED)., 1982) KANDIAH, PAcetobactor xylinum was grown in a sucrose phosphate medium. The time taken to reach the late log phase depends on the age of the inoculum. When grown in a medium containing surfactant the amount of protein too increased other than the wet weight. Storage temperatures of Acetobactor xylinum extracts affects the activity of sucrose phosphorylase. Synthesis of scucrose using sucrose phosphorylase from preparations of Acetobactor xylinum was measured by the decrease in concentration of fructose Phosphatses and Invertase were found to deorease the synthesis of sucrose.Item A Study of the effect of tea on the metabolism of caffeine(University of Colombo: UC(MED)., 1982) JAYAWARDENA, SSSBDPTissue distribution studies of (1-methyl - C14) caffeine showed that caffeine was readily absorbed from the gastrointestinal tract. The peak blood level of radioactivity was observed 3 hours after oral administration. The blood level then rapidly declined. When caffeine was administrated with tea infusion, the peak radioactivity in blood was reached after 6 hours. The blood level remained high over long period. Liver, kidney, testes and heart muscles showed high level of radioactivity. When caffeine was administrated with tea, the tissue distribution profile showed a biphasic pattern. Highest content of radioactivity was associated with the testes. Following oral administration of (1- methyl - C14) caffeine to rats, the drug or its metabolites were excreted in urine. Approximately 62 percent of the administrated radioactivity was excreted by male rats. While females excreted approximately 67 percent. The greater part of urinary excretion in both sexes occurred during 12 - 24 hours. Small amounts (6 - 10 percent) of radioactivity were detected in faeces. Administration of caffeine with tea infusion resulted in an increase in urinary excretion in both sexes. The overall results tissue distribution, excretion and metabolism studies of pure caffeine and caffeine with tea, suggested a possible reduction in the bioavailability of caffeine by other component(s) in tea.Item A Investigation of faceal pollution in water used for domestic purposes in two highly congested areas in and around the municipal limits of Colombo.(University of Colombo: UC(SCI)., 1982) FERNANDO, RVAn Investigation of faecal poiiution of water used for domestic purposes,in two highly congested areas, was carried at Kelaniya and Mattakuliya. The Henamulla Camp at Thotalanga (below the old Kelaniya bridge) is a highly condested tenement area. The Camp is of two settlements one being situated in close Proxmity to a very extensive Land reclamation site,which is filled with decomposing "Rubbish" There is also a large sewage drain believed to have been built more than forty years age. This drain carries inadequately treated domestic sewage from a very poorly functioning sevage treatment plant. which is about half a mile away from this area. The second settlement is more congested, and is clearly demarcated from the first, by a bund that runs acrose the marshy land that lies between the two schemes. "Kakkaduwa" (Crow Island) is a highty inhabited area in Mattakkuliya, situated behind the Mattakuliya Bus depot, and stretching towards the mounh of the Kelani River. This area provides a fair portion of habitable land for many fisher folk.Item Sucrose phosphorylase catalyzed synthesis of sucrose and its isolation from Pseudomonas saccharophila(University of Colombo: UC(MED)., 1982) WIJERATNA, SPseudomonas saccharophila was grown in sucrose phosphate medium. When the age of the inoculum was increased from 10 hrs to 100 hrs, the time taken to reach late log phase decreased, attained a minimal value and again increased. The minimal value of late log phase was 20 hrs when the inoculum was 30 hrs old. Tween 20 and tween 80 were tested for any stimulatory effect on growth and enzyme activity. Tween 20 reduced the time taken to reach late log phase ie, half that of normal, while tween 80 was without effect. As regards sucrose phosphorylase activity, the results indicate both tween 20 and tween 80 had no inductive effect. Using ammonium sulphate fractionation the precipitate obtained between 50 - 60 percent saturation shown the highest specific activity (30.4 units/mg) and percentage recovery was 41. The purification achieved was 61 fold. Further purification was done by hydrophobic interaction chromatography where sucrose phosphorylase was eluted with O.1M, C104 ions. The percebtage recovery after hydrophobic chromatography was 34 and enzyme was 103 folds pure. The specific activity was 48.4 units/mg. At this stage of purity, sucrose phosphorylase had no invertase activity. The sucrose phophorylase obtained by 50-60 percent (NH4)2SO4 saturation was tested for stability at -2 c, 4 C and 29 C over a month. The enzyme was not affected at 4 C while at 29 C and -2 C the loss of activity were 28 percent and 99 percent respectively after 15 days. The optium temperature for sucrose phosphorylase activity was found to be 30 C. The (NH4)2SO4 fractionated sucrose phosphorylase was used in sucrose synthesis, production of sucrose was confirmed by paper chromatography. When the equilibrium was not disturbed the sucrose synthesis acheived was 55 percent of the imitial glucose concentration present in glucose-l-phosphate. When the equilibrium was disturbed the sucrose synthesized increased to 98 percent. There was a significant increase in the synthesis of sucrose in the presence of phosphatase inhibitors.