Browsing by Author "Gunathilaka, H.N."

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Establishment and maintenance of laboratory colonies of Aedes albopictus mosquitoes
(University of Peradeniya, 2015) Wijegunawardana, A.D.; Gunathilaka, H.N.; Dassanayake, R.; Gunawardene, Y.I.N.S.; Abeyewickreme, W.
With a mission of "providing authenticated, high-quality Aedes albopictus mosquito rearing information to the research community" maintenance of a Ae. albopictus mosquito colony was started. All environmental facilities inside the insectary were carefully maintained to better suit the Ae. albopictus mosquito colonization. The mean temperature of 27°C (± 0.5°C) was constantly maintained inside the insectary. Wet towels on adult mosquito cage racks were used for proper maintenance of humidity. Lighting was using fluorescent light and regulated with 16:8 hour continuous dark and light period. Pest insect was controlled to ensure essential absence of ants and cockroaches. This was achieved without any harm to the mosquito colonies either directly or by contamination with toxicants transported by pests. An adult mosquito trap placed inside the insectary was used to monitor released mosquitoes. Consistent effort was also made to improve the level of cleanliness inside the insectary. Written guidelines were given to each person responsible for a task. Insectary operations included egg counting, preparation of hatching bottles with boiled distilled water following cooling to room temperature, egg hatching, larvae rearing with International Atomic Energy Agency (IAEA) recommended diet of tuna meal, bovine liver powder, brewery yeast and vitamin complex in a ratio of 37.5:27:10.5:2 g in 1L up to one week, pupae counting and putting into adult emergency cages, adult male feeding with 10% sugar solution with Vitamin complex, adult female blood feeding from 4th day onwards with bovine blood, placing egg laying cups and collecting egg laying cups, drying egg papers and starting next generation from the dried eggs. Adult mosquito cages were blood fed every 4th day after emergence from pupa and for quality control reasons each adult cage was blood fed only 3 times and there after only 10% sugar solution with vitamin syrup was supplemented until all adult mosquitoes died. Documentation for maintenance and data record was maintained and updated daily. Records included larvae feeding records, larvae tray maintenance and cleaning charts, adult feeding records with both sugar solution and blood, insectary cleaning records with time and dates. Number of eggs and percentage of egg hatching, larvae death, pupation, adult emergence, egg laying and adult mosquito death with respect of the sex and time difference were recorded. For bio-safety reasons all discarded material from larvae trays, egg laying cups and adult cages were boiled thoroughly to facilitate total destruction of the contaminated mosquito eggs. All other infectious material were incinerated. Finally, all above conditions facilitated achievement of 100% egg hatching rate within maximum of 24 hours, 100% survival of larvae to pupa (~ 7 days), 100% survival of pupated larvae to adult emergence (~ 2 days) and 95.5% adult survival up to 12 days. No difference was observed on adult longevity between males and females within first 12 days of adult emergence. However, approximate life span for males (-17 days) was lower than the females (~ 25 days) and the mortality was regular through all generations (Fl to F21).
Evaluation of the spatial and temporal trends of dengue outbreaks in Gampola, Central Province, Sri Lanka
(University of Peradeniya, 2015) Udayanaga, N.W.B.A.L.; Gunathilaka, H.N.; Iqbal, M.C.M.; Abeyewickreme, W.
Dengue is the world's fastest growing vector borne disease, and it has become one of the major health concerns in many countries including Sri Lanka. Despite immense efforts and control strategies it claims 30,000 - 35,000 deaths per year, making dengue a priority heath issue in Sri Lanka. Investigation of the recent trends of dengue outbreaks on both a spatial and temporal scale is of high importance in drafting and implementing effective management/action plans to ensure successful management and control of dengue epidemics on a regional scale. Hence, a statistic and geo informatics based analysis of the recent trends in dengue distribution was carried out to identify spatial and temporal trends in distribution patterns of dengue in the Gampola Medical Officer of Health (MOH) division. Monthly records of reported dengue cases from 2009 to 2013 of the Gampola MOH division were collected. A scatter plot analysis in MINITAB (version 14.12.0) was devised to identify the temporal patterns in the reported dengue cases. Arc GIS (version 10.1) was devised to develop spatial maps (at the GND level) of the recorded dengue case distribution for each month and for the whole study period, for Gampola. Furthermore, spatial (at GND level) and temporal (annual) variations in dengue outbreak distribution within the Gampola MOH were analyzed to recognize the recent trends in dengue distribution. Gampola East, Gampola West, Illawathura, Keerapane, Kahatapitiya, Egodakalugamuwa and Pussellawa localities emerged as high-risk areas, while Polkumbura, Kurukude, Galgediyawa, Amuhena and Hunukotugama emerged as low risk areas for dengue outbreaks. Further localities, namely Godagama, Kalugalhinna, Kekulanda, Millagaspitiya, Sinhapitiya North, Sinhapitiya South, Pussellawagama, Ranawala and Wanahapuwa remained unchallenged by dengue throughout 2009 - 2013. The paired-Chi square test revealed significant spatial and temporal variations in the emergence of dengue outbreaks within the Gampola MOH throughout the study period \>x2 w. 0.95} = 65.156]. Regionalized evaluation of recent trends in temporal and spatial distribution of dengue outbreaks are recommended in the design and implementation of management plans to control the rise of dengue, and also in the evaluation of the effectiveness of already implemented practices taken to reduce and control dengue outbreaks, by the government sector and other relevant entities.
Optimization of the cell culture media to obtain the most effective nutrient concentrations in the medium for the growth and maintenance of the Myeloma cells
(University of Peradeniya, 2015) Munasinghe, M.M.E,; Athapaththu, A.M.M.H.; Gunathilaka, H.N.; Abeyewickreme, W.
Cell culture can be described as the removal of cells, tissues or organs from an animal or a plant and their subsequent placement into an artificial environment. Basically, proper temperature, substrate for cell attachment, appropriate growth medium and correct pH and osmolality in the medium should be properly maintained in order to achieve a better growth in the cells. Typically, a culture medium is composed of a complement of amino acids, vitamins, inorganic salts, glucose, and serum as a source of growth factors, hormones, and attachment factors. The objective of this study is to optimize culture media in order to obtain the most effective nutrient concentrations in the medium for the growth/maintenance of NSO Myeloma cell. Myeloma cells for the monoclonal antibody production were prepared using Dulbecco's Modified Eagle Medium (DMEM) as the growth media for the NSO cell culture. In this study, the culture media was optimized in order to obtain the most effective concentrations in the media. Primarily, in order to culture the cells soon after thawing, 10% growth media was used and then the grown cells were transferred in to a nutrition rich media- Hypoxanthine Thymidine (HT) medium. The growth of the Primary cell culture, soon after thawing, was observed within 2 days of culturing. A 60% of the bottom of the culture flask was covered with the healthy NSO myeloma cells. The transferred cells were also grown to a rate of 60% within 2 days of transferring. The 10% growth media comprises with 422 mL of DMEM with added 4500 mg/L glucose without L-glutamine and sodium pyruvate, 50 mL of Fetal Clone Serum, IZ5 mL of 1M HEPES buffer (4-(2-hydroxyethyl)-l-piperazineethanesulfonic acid), 5 m of 200 mM Glutamin, 5 mL of 100X Non-essential amino acids, 5 mL of 100 mM Sodium pyruvate and 0.5 mL of 55mM jj-mercaptoethanol. The HT medium comprises with 366.5 422 mL of DMEM with added 4500 mg/L glucose without L- glutamine and sodium pyruvate, 100 of mL FetalClone serum, 12.5 mL of 1M HEPES buffer, 5 mL 100X HT supplement, 5 mL of 200 mM Glutamin, 5 mL of 100X Non-essential amino acids, 5 mL of 100 mM Sodium pyruvate, 0.5 mL of 50 mg/mL Genatamicin, 0.5 mL of 55 mM p-mercaptoethanol and 25 uL of Interlukin-6. Since both the culture media showed optimum growth of the Myeloma cells, the above protocol with the provided concentrations of the nutrients could be used to maintain/ grow NSO myeloma cell line in the laboratory.