Browsing by Author "Amaratunga, C."

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Comparison of gastric emptying of a solid meal with a semi-solid meal using real-time ultrasonography in a cohort of healthy individuals
(Faculty of Graduate Studies, University of Kelaniya, 2015) Amarasiri1, D.L.; Devanarayana, N.M.; de Silva, M.; Amaratunga, C.; Madushanka, K.B.G.; de Silva, H.J.
Aims Routine performance of solid gastric emptying (GE) to assess gastroparesis is not feasible due to prolonged test duration and cumbersome preparation of test meals. Substitution of a commercially prepared semisolid meal could increase feasibility. This study compared GE of a solid and semi-solid meal. Methods and materials used Thirty (30) healthy volunteers underwent gastric emptying by real-time ultrasonography after partaking a solid meal (Mung kiribath) and semi-solid meal (‗Nestum mung‘) on two separate days. The calorie content of each meal was 350 Kcal and consisted of approximately 60% carbohydrates, 30% fat and 10% proteins. The pyloric antral area, amplitude and frequency of contractions were measured at 5, 15, 30, 45, 60, 90, 120, 150, 180, 210 and 240 minutes after ingestion. GE parameters were compared and correlated by using Wilcoxon Signed Ranks test and Spearman Rank Correlation. A P<0.05 was considered as statistically significant. Results The subjects were 17 males (mean (SD) age 29.4 (6.0) years, BMI 23.4 (2.94)) and 13 females (mean (SD) age 37.2 3 (11.9) years, BMI 22.9 (4.34)). Mean (SE) fasting antral area, antral areas, gastric emptying rates (GER) and gastric residual ratios at each time point did not differ significantly between the meals. At the end of 4 hours, the mean emptied percentage of the semisolid meal and solid meal was 81.1% and 70.6% respectively. GER of semisolid meal at 90min significantly correlated with GER at 240min. There was no correlation of the solid meal with the 90min and 240min GER. Conclusions A semisolid meal could be substituted in place of a solid test meal. A gastric emptying test can be performed in 90min when utilizing a semisolid meal as opposed to 4 hours when utilizing a solid meal. Ease in preparation of the semisolid meal and reduction in test time increases test feasibility.
Protection against malaria in toque mokeys immunized with p.cynomolgi MSP1inv in alum
(Sri Lanka Association for the Advancement of Science, 2000) Amaratunga, C.; Nandasiri, K.; Weerasinghe, S.; Manamperi, A.; Holm, I.; Longacre, S.; Handunnetti, S.
Immunization of toque monkeys with baculovirus-expressed, His-tagged recombinant plasmodium cynomoigi ceylonensis (Pcc) C-terminal 19 kDa proteins of the major merozoite surface protein 1 (MSP1inv) with Freunds adjuvant, mediates long-term protection against homologous and heterologous p. cynomolgi blood-stage challenge infection. However, Freunds adjuvant is unsuitable for use in humans, which necessitates the testing of alternative adjuvants. Antigen-alum formulation and binding was optimized for the new preparation of matalloaffinity-purified MSP1inv antigen, under conditions acceptable for human trails, including 800ug aluminium per dose, in accordance with the permitted FDA maximum. This formulation was used in an immunization trial using the p. cynomolgi-toque monkeys system, which is analogous to the p.vivax-human system. Group 1 comprising 4 animals were immunized with alum+MSP1inv , and group 2 comprising 3 monkeys received alum alone. Four doses of immunization were given intramuscularly at 0,1,3 and 4 month intervals. After immunization, the anti-MSP1inv antibody titres of immunized animals reached 2.8x104 . all animals were given a homologous Pcc challenge infection one month after the last dose of immunization. One of the four immunized animals was completely protected while the other 3 animals showed low patent parasitaemia, resulting In an overall partially protective effect (p=0.02). immunization with alum did not result in sterile immunity, as seen with Freunds, where antibody titres range from 106 - 107 . Following treatment, the animals were given a second heterologous, blood-stage challenge infection of p.cynomolgi Gombak, (PcG) four months after the first challenge infection. Sequence analysis of PcG DNA reveald a single amino acid differing from that of Pcc. The substitution which occurs at the nt 207 position in the C-terminal 19-kDa sequence changes the amino acid glutamate into lysine. Statistically significant partial protection was observed in the immunized animals (p=0.04), despite having a lower titre of antibodies (3.3x103) at the time of re-challenge. Together with sequence data, this documents the ability of recombinant MSG1inv to protect against a heterologous infection.
Protection against malaria in toque monkeys immunized with P. cynomolgi MSPI-19 in alum
(The royal society of tropical medicine and hygiene, British society for parasitology, The American society of tropical medicine and hygiene, 2000) Amaratunga, C.; Nandasiri, K.; Weerasinghe, S.; Manamperi, A.; Longacre, S.; Holm, I.; Handunnetti, S.
In a pre-clinical trail of a vaccine against P.vivax malaria, toque monkeys were immunized with matalloaffinity-purified baculovirus-expressed. His-tagged recombinant Plasmodium cynomolgy ceylonensis (Pcc) C-terminal 19 kDa protiens of the major merozoite surface protein 1 (MSP1p19) with alum, under conditions acceptable for clinical trials. The P. cynomolgi-toque monkey system is highly analogous to P.vivax in humans. Eight animals were immunized with alum+MSP1p19 and 3 monkeys received alum alone. After four doses, the anti-MSP1p19 antibody titres of immunized animals reached 2.8x104. all animals were challenged with Pcc asexual blood stage parasites. The immunized animals showed significant, partial protection (p=0.0024). Four of these animals were given a second heterologous challenge infection of p.cynomolgi Gombak, (PcG) four months after the first challenge infection. Sequence analysis of PcG DNA revealed a single amino acid challenge differing from that of Pcc. The substitution which occurs at the nt 207 position in the C-terminal 19-kDa sequence changes the amino acid glutamate into lysine. Statistically significant protection was observed in the immunized animals (p=0.04), despite having a lower titre of antibodies at the time of re-challenge. This documents the ability of recombinant MSP1p19 with alum to protect against Pcc and PcG infections.