29 results on '"Rajapaksha, R."'
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2. An interpretable time series machine learning method for varying forecast and nowcast lengths in wastewater-based epidemiology.
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Lai M, Wulff SS, Cao Y, Robinson TJ, and Rajapaksha R
- Abstract
Wastewater-based epidemiology has emerged as a viable tool for monitoring disease prevalence in a population. This paper details a time series machine learning (TSML) method for predicting COVID-19 cases from wastewater and environmental variables. The TSML method utilizes a number of techniques to create an interpretable, hypothesis-driven framework for machine learning that can handle different nowcast and forecast lengths. Some of the techniques employed include:•Feature engineering to construct interpretable features, like site-specific lead times, hypothesized to be potential predictors of COVID-19 cases.•Feature selection to identify features with the best predictive performance for the tasks of nowcasting and forecasting.•Prequential evaluation to prevent data leakage while evaluating the performance of the machine learning algorithm., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 Published by Elsevier B.V.)
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- 2023
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3. Characterization of Uromyces appendiculatus First Races in Sri Lanka and Identification of Genes for the Development of Rust-Resistant Snap Beans.
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Kumari HMPS, Pastor Corrales MA, Rajapaksha RGAS, Bandaranayake PCG, and Weebadde C
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- United States, Sri Lanka, Phaseolus genetics, Basidiomycota genetics
- Abstract
Bean rust is a devastating disease of snap beans in Sri Lanka. Our study endeavored to develop snap beans with resistance to Uromyces appendiculatus , the bean rust pathogen reported to have numerous virulent races. Accordingly, we needed a detailed understanding of the virulence of U . appendiculatus and to identify genes conferring effective rust resistance. To investigate the virulence, we collected leaves of snap bean with rust symptoms from four snap bean producing districts of Sri Lanka. From these samples we established 57 single pustule isolates. Each isolate was inoculated on a set of 12 differential cultivars, six from the Andean and six from the Middle American gene pools of common bean. The virulence of the isolates segregated into four distinct groups that comprised the first four reported races of U. appendiculatus in Sri Lanka, 23-5, 31-1, 31-11, and 63-21. All races were significantly more virulent on the Andean than on the Middle American differential cultivars. PI 1819966, a Middle American differential cultivar containing the Ur-11 gene, conferred resistance to all four races. Three other Middle American cultivars were resistant to three races. Conversely, five Andean differential cultivars were susceptible to all four races. PI 160418 was the only Andean differential cultivar with resistance to three races. The results suggested that rust resistance genes from the Middle American differential cultivars could be combined in different ways with the resistance of Andean PI 260418 to develop snap bean varieties with broad resistance to all races of U. appendiculatus in Sri Lanka., Competing Interests: The author(s) declare no conflict of interest.
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- 2023
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4. Empowering Communities During the COVID-19 Pandemic Through Mothers' Support Groups: Evidence From a Community Engagement Initiative in Sri Lanka.
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Wijesinghe M, Gunawardana B, Weerasinghe W, Karunarathne S, Vithana V, Rajapaksha R, Batuwanthudawe R, and Karunapema R
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- Female, Humans, Mothers, Pandemics prevention & control, Emergencies, Sri Lanka epidemiology, Power, Psychological, COVID-19 prevention & control, Zika Virus, Zika Virus Infection
- Abstract
Community empowerment has previously been used to mitigate the effects of health emergencies, such as outbreaks of Ebola virus disease and Zika virus. In Sri Lanka, mothers' support groups (MSGs) aim to promote community health, well-being, and nutrition practices through community engagement. With the emergence of the COVID-19 pandemic, MSGs were mobilized by the Health Promotion Bureau in response to the pandemic. Key activities MSGs engaged in during the COVID-19 response included establishing communication networks, creating a supportive environment for preventive behaviors, organizing vaccination clinics, distributing essential food and medicine, organizing recreational activities, promoting home gardening, and monitoring community activities. We examine how these community-based empowerment initiatives successfully assisted in the pandemic response. Health officials can help to build more resilient communities that are better prepared for future health emergencies by valuing the community-level methods used in overcoming COVID-19 and further strengthening the skills of community group members., (© Wijesinghe et al.)
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- 2023
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5. Health seeking behaviours, dengue prevention behaviours and community capacity for sustainable dengue prevention in a highly dengue endemic area, Sri Lanka.
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Rajapaksha RMNU, Abeysena C, and Balasuriya A
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- Aged, Humans, Middle Aged, Cross-Sectional Studies, Patient Acceptance of Health Care, Sri Lanka epidemiology, Surveys and Questionnaires, Health Behavior, Dengue epidemiology, Dengue prevention & control
- Abstract
Introduction: Dengue has become a major health problem in globally as well as locally. The delay in health-seeking is significantly associated with complications leading to severe dengue and active engagement of communities needs to minimize the delays in management to control epidemics. The aim of the study was to evaluate the relationship between sociodemographic characteristics and householders' Health-Seeking Behaviours (HSB), Dengue-Prevention Behaviours (DPB), and Community Capacities (CC) for sustained dengue prevention in Sri Lanka, a country with a high dengue endemicity., Methods: A cross-sectional analytical study was carried out in a district with the highest dengue endemicity from January to April 2019. Of the householders, 532 were chosen randomly. A pre-tested, validated, and interviewer-administered questionnaire was used to assess HSB and DPB. The HSB was assessed using three aspects, initial response for fever management, the duration of blood testing and initial response if suspected dengue. The DPB assessment was evaluated using 'waste, outdoor water container, indoor water container, roof gutter and water storage management'. 'Dengue Community Capacity Assessment Tool', with 14 key items was used to assess the level of community capacity for dengue prevention. Out of the total, ≥ 50% was considered as an "adequate" HSB, DPB and CC. Multiple logistic regression was performed to control confounding effects. The results were expressed as adjusted Odds-Ratios (aOR) and 95% Confidence Intervals (CI)., Results: The response rate was 93.2% (n = 496). Among them, 44.6% (n = 221) had adequate overall HSB, and 19.2% (n = 95) had adequate DPB. Householders who have ≤ 4 family members are 1.74 times (aOR = 1.74; 95% CI: 1.17 - 2.61) more likely to have adequate HSB and 1.85 times (aOR = 1.85; 95% CI: 1.11 - 3.09) more likely to have adequate DPB. The age group of 46 to 70 years' individuals (aOR = 1.74; 95% CI:1.12 - 2.92), and who engaged in employment (aOR = 1.68; 95% CI: 1.05 - 2.67) were more likely to have adequate DPB than the group of 18 to 45 years and the non-employed individuals respectively. Of them, 24.6% (n = 122) perceived that they have adequate CC. The householders who have per-capita income < USD 50 are 1.95 times (aOR = 1.95; 95%CI:1.11 - 3.40) more likely to have adequate CC., Conclusion: The HSB, DPB and CC need to be improved to change the behaviour for sustainable dengue prevention and community capacity-building programmes need to be conducted in the Kurunegala district, Sri Lanka., (© 2023. The Author(s).)
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- 2023
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6. In vitro and in silico studies of silver nanoparticles (AgNPs) from Allium sativum against diabetes.
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Jini D, Sharmila S, Anitha A, Pandian M, and Rajapaksha RMH
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- Humans, alpha-Glucosidases, Diabetes Mellitus drug therapy, Glucose, Molecular Docking Simulation, Plant Extracts pharmacology, Plant Extracts chemistry, Silver pharmacology, Silver chemistry, Spectroscopy, Fourier Transform Infrared, Garlic chemistry, Hypoglycemic Agents pharmacology, Hypoglycemic Agents chemistry, Insulins, Metal Nanoparticles chemistry
- Abstract
In the present study, the silver nanoparticles (AgNPs) were synthesized from the bulbs of Allium sativum, characterized by UV-visible spectroscopy, FT-IR, SEM, HR-TEM, EDAX analysis and investigated its action on the inhibition of starch digestion. The results proved that the biosynthesized nanoparticles were uniformly dispersed, spherical shaped with the size ranging from 10 to 30 nm. The phytochemical and FT-IR analysis showed the presence of phenols, terpenoids, and amino acids in the synthesized AgNPs. The cytotoxicity analysis revealed that the synthesized AgNPs were non-toxic to the normal cells. The synthesized AgNPs exhibited significant free radical scavenging activity. The in vitro antidiabetic activity showed that the synthesized AgNPs increased glucose utilization, decreased hepatic glucose production, inhibited the activity of starch digestive enzymes such as α-amylase and α-glucosidase, and were not involved in the stimulation of pancreatic cells for the secretion of insulin. The in silico antidiabetic activity analysis (molecular docking) also revealed that the silver atoms of the AgNPs interacted with the amino acid residues of α-amylase, α-glucosidase, and insulin. The present study proved that the AgNPs synthesized from A. sativum have prominent antidiabetic activity in terms of reducing the hyperglycemia through the increased glucose utilization, decreased hepatic glucose production, and the inhibition of α-amylase and α-glucosidase enzymes. So it can be used as a promising nanomedicine for the treatment of diabetes., (© 2022. The Author(s).)
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- 2022
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7. Success and challenges of health systems resilience-enhancing strategies for managing Public Health Emergencies of International Concerns (PHEIC): A systematic review protocol.
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Rajapaksha RMNU, Khatri RB, Abeysena C, Wijesinghe MSD, Endalamaw A, Thomas TK, Perera N, Rambukwella R, De Silva G, Fernando M, and Alemu YA
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- Humans, Government Programs, Systematic Reviews as Topic, Emergencies, Public Health
- Abstract
Introduction: Health systems resilience is the ability to prepare, manage and learn from a sudden and unpredictable extreme change that impacts health systems. Health systems globally have recently been affected by a number of catastrophic events, including natural disasters and infectious disease epidemics. Understanding health systems resilience has never been more essential until emerging global pandemics. Therefore, the application of resilience-enhancing strategies needs to be assessed to identify the management gaps and give valuable recommendations from the lessons learnt from the global pandemic., Methods: The systematic review will be reported using the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA-P) protocols guideline. Reporting data on World Health Organization (WHO) health system building blocks and systematic searches on resilience enhancing strategies for the management of Public Health Emergencies of International Concerns (PHEIC) after the establishment of International Health Regulations (IHR) in 2007 will be included. The search will be conducted in PubMed, Scopus, Web of Science and Google Scholar ETHICS AND DISSEMINATION: Ethics approval and safety considerations are not applicable. Pre-print of the protocol is available online, and the screening of the articles will be done using Rayyan software in a transparent manner. The findings will be presented at conferences and the final review's findings will be published in a peer-reviewed international journal and will be disseminated to global communities for the application of successful management strategies for the management of future pandemics., Prospero Registration Number: CRD42022352612; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022352612., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)
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- 2022
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8. Rhodium-Based Metal-Organic Polyhedra Assemblies for Selective CO 2 Photoreduction.
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Ghosh AC, Legrand A, Rajapaksha R, Craig GA, Sassoye C, Balázs G, Farrusseng D, Furukawa S, Canivet J, and Wisser FM
- Abstract
Heterogenization of molecular catalysts via their immobilization within extended structures often results in a lowering of their catalytic properties due to a change in their coordination sphere. Metal-organic polyhedra (MOP) are an emerging class of well-defined hybrid compounds with a high number of accessible metal sites organized around an inner cavity, making them appealing candidates for catalytic applications. Here, we demonstrate a design strategy that enhances the catalytic properties of dirhodium paddlewheels heterogenized within MOP (Rh-MOP) and their three-dimensional assembled supramolecular structures, which proved to be very efficient catalysts for the selective photochemical reduction of carbon dioxide to formic acid. Surprisingly, the catalytic activity per Rh atom is higher in the supramolecular structures than in its molecular sub-unit Rh-MOP or in the Rh-metal-organic framework (Rh-MOF) and yields turnover frequencies of up to 60 h
-1 and production rates of approx. 76 mmole formic acid per gram of the catalyst per hour, unprecedented in heterogeneous photocatalysis. The enhanced catalytic activity is investigated by X-ray photoelectron spectroscopy and electrochemical characterization, showing that self-assembly into supramolecular polymers increases the electron density on the active site, making the overall reaction thermodynamically more favorable. The catalyst can be recycled without loss of activity and with no change of its molecular structure as shown by pair distribution function analysis. These results demonstrate the high potential of MOP as catalysts for the photoreduction of CO2 and open a new perspective for the electronic design of discrete molecular architectures with accessible metal sites for the production of solar fuels.- Published
- 2022
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9. Role of Religious Leaders in COVID-19 Prevention: A Community-Level Prevention Model in Sri Lanka.
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Wijesinghe MSD, Ariyaratne VS, Gunawardana BMI, Rajapaksha RMNU, Weerasinghe WMPC, Gomez P, Chandraratna S, Suveendran T, and Karunapema RPP
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- Community Participation, Humans, Pandemics, SARS-CoV-2, Sri Lanka, COVID-19
- Abstract
The COVID-19 pandemic has affected all countries irrespective of their state of development. In countries with traditional societies, religious leaders have been acknowledged as key stakeholders in community engagement activities, including disease prevention. A community-level prevention model was established in 2020 by the Health Promotion Bureau (HPB), Sri Lanka, which incorporated mobilisation of the clergy to support the prevention and response schemes to COVID-19 with non-governmental stakeholders. This model was part of a more extensive community engagement network established by the HPB in cooperation with the country offices for WHO and UNICEF. Building trust, empowering behavioural traits applicable to minimise risks from COVID-19, leadership and coordination, message dissemination, addressing stigma and discrimination, supporting testing procedures, contact tracing activities and vaccination, building community resilience, spiritual and psychosocial support, and welfare provision are some of the useful factors that were identified in the model. Furthermore, a much broader and holistic approach is needed to focus on health behaviours and social and cultural aspects in a multi-faceted nature. This paper highlights a novel COVID-19 prevention model with active involvement of religious leaders that can be implemented in low resource settings. Our experience from Sri Lanka demonstrates the feasibility of implementing this model to mitigate the disastrous situation following the COVID-19 outbreak., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
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- 2022
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10. Antiviral Potential of Selected Medicinal Herbs and Their Isolated Natural Products.
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Perera WPRT, Liyanage JA, Dissanayake KGC, Gunathilaka H, Weerakoon WMTDN, Wanigasekara DN, Fernando WSK, Rajapaksha RMH, Liyanage RP, and Perera BT
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- Animals, Humans, Antiviral Agents pharmacology, Biological Products pharmacology, Plants, Medicinal chemistry, Virus Diseases drug therapy, Viruses drug effects
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Viruses are responsible for a variety of human pathogenesis. Owing to the enhancement of the world population, global travel, and rapid urbanization, and infectious outbreaks, a critical threat has been generated to public health, as preventive vaccines and antiviral therapy are not available. Herbal medicines and refined natural products have resources for the development of novel antiviral drugs. These natural agents have shed light on preventive vaccine development and antiviral therapies. This review intends to discuss the antiviral activities of plant extracts and some isolated plant natural products based on mainly preclinical (in vitro and in vivo) studies. Twenty medicinal herbs were selected for the discussion, and those are commonly recognized antiviral medicinal plants in Ayurveda ( Zingiber officinale , Caesalpinia bonducella , Allium sativum , Glycyrrhiza glabra , Ferula assafoetida , Gymnema sylvestre , Gossypium herbaceum , Phyllanthus niruri , Trachyspermum ammi , Withania somnifera , Andrographis paniculata , Centella asiatica , Curcuma longa , Woodfordia fruticose , Phyllanthus emblica , Terminalia chebula , Tamarindus indica , Terminalia arjuna , Azadirachta indica , and Ficus religiosa) . However, many viruses remain without successful immunization and only a few antiviral drugs have been approved for clinical use. Hence, the development of novel antiviral drugs is much significant and natural products are excellent sources for such drug developments. In this review, we summarize the antiviral actions of selected plant extracts and some isolated natural products of the medicinal herbs., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 W. P. R. T. Perera et al.)
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- 2021
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11. Human Otoacariasis in Two Climatically Diverse Districts in Sri Lanka: Seasonality, Risk Factors, and Case Notes.
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Bandaranayaka KO, Kularatne SAM, Rajapakse RPVJ, Abeysundara UB, Rajapaksha RMMA, and Rajakaruna RS
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- Animals, Female, Follow-Up Studies, Humans, Risk Factors, Sri Lanka epidemiology, Rickettsia, Tick Infestations epidemiology, Tick Infestations veterinary
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Purpose: Otoacariasis is a parasitic otopathy reported in many parts of the world. This study presents the seasonal pattern, risk factors, and case notes on human otoacariasis in two climatically different districts: Anuradhapura and Kandy in the Dry and Wet/Intermediate zone of Sri Lanka, respectively., Methods: Ticks removed from the ear canal of patients were collected. Risk factors of otoacarisis were determined by a case/control follow-up study., Results: Nymphal Dermacentor auratus (90.8%) was the main tick species associated otoacariasis. In the Kandy District, infestation was year-round, while in the Anuradhapura District, it was seasonal with a peak in December-February. Children < 10 years were a risk group in both districts. Females were a risk group in the Kandy District. Engagement in outdoor activities was a risk factor in both districts. In addition, the presence of wildlife and domesticated animals were risk factors in the Kandy and Anuradhapura districts, respectively. The treatment protocols in the two hospitals were different. An infant with otoacariasis from the Anuradhapura District developed rickettsia., Conclusions: Although the tick species was the same, seasonality, risk groups, and risk factors in the two districts were different which could be due to the establishment and persistence of tick populations influenced by biotic and abiotic factors., (© 2021. Witold Stefański Institute of Parasitology, Polish Academy of Sciences.)
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- 2021
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12. Influence of Vertebrate Excreta on Attraction, Oviposition and Development of the Asian Tiger Mosquito, Aedes albopictus (Diptera: Culicidae).
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Rajapaksha RDT, Jayatunga DPW, and Ganehiarachchi GASM
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Aedes albopictus is an important vector of dengue worldwide. Eliminating dengue in Sri Lanka depends entirely on controlling the vector and human-vector contact. Thus, studying the bionomics and behavior of Ae. albopictus is paramount. The objective of this study was to evaluate the effect of the excreta of cow, goat and pig on the attraction, oviposition and development of Ae. albopictus . Bioassay chambers determined the mosquito stimulatory response. Ovitraps determined Ae. albopictus oviposition preference to excreta singly, in combination and on fermentation. The excreta effect on larval development was also determined. The results revealed that Ae. albopictus gravid females were significantly attracted to goat excreta but were repelled by pig excreta. The oviposition preference was highest for cow excreta and lowest for pig excreta. For excreta combinations, the Cow+Goat combination increased the oviposition while the Pig+Goat combination reduced the oviposition. The oviposition preference of Ae. albopictus increased with the rate of fermentation. The pig excreta increased the Ae. albopictus larval mortality, larval and pupal duration and reduced adult fecundity, whereas the cow excreta positively affected all these aspects. Our findings additionally suggest that a high abundance of Ae. albopictus in rural areas of Sri Lanka may be due to its oviposition attraction and growth performance for vertebrate excreta.
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- 2021
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13. Hump-nosed pit viper (Hypnale hypnale and Hypnale zara) envenoming in Deniyaya, Sri Lanka: Epidemiological and clinical features from a prospective observational study.
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Witharana EWRA, Gnanathasan A, Dissanayake AS, Wijesinghe SKJ, Kadahetti SCL, and Rajapaksha RMJK
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- Adolescent, Adult, Animals, Crotalid Venoms, Female, Humans, Male, Middle Aged, Sri Lanka epidemiology, Crotalinae, Snake Bites epidemiology
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Hypnale hypnale, Hypnale zara and Hypnale nepa are the three species of Hump nosed pit vipers that are implicated in human bites in Sri Lanka. H. zara and H. nepa are two endemic species to the country. The objective of the study was to characterize epidemiology and clinical features after different Hump nosed pit viper species bites. A prospective observational study was conducted in Base Hospital Deniyaya from 2013 to 2015. Hump nosed pit viper as the offending snake was identified when the victims brought live or dead specimens. Species identification of dead specimen was done by a herpetologist. Clinical details were recorded during the hospital stay. 83 Hump nosed pit viper bite patients (19-81 years) were studied. Fifty two dead specimens were identified as 39 of H. zara and 13 of H. hypnale by the herpetologist. No H. nepa was identified. Thirty one live snakes were identified as Hump nosed pit vipers and released in to the wild. Envenoming was reported throughout the year. Eighty (96.4%) were daytime bites. Hands (43.4%), feet (55.4%) and arms (1.2%) were affected sites. Sixty two (74.7%) were bitten in tea plantations. All had pain over bite site. Overall, sixty nine (83.1%) had local swelling, seven (8.4%) extensive limb swelling, nineteen (22.9%) haemorrhagic blisters, and seven (8.4%) regional lymphadenopathy. Four (4.8%) patients had incoagulable blood by 20WBCT. H. zara bites had 28.2% haemorrhagic blisters, 7.7% extensive limb swelling and 2.6% coagulopathy. H. hypnale bites had 7.7% each extensive limb swelling and coagulopathy and 23.1% haemorrhagic blisters. None developed elevated serum creatinine. Neurotoxicity was not noted. Hump nosed pit viper bites caused substantial morbidity. Risk factors included day time outdoor activities and occupation. Pain, extensive limb swelling, bite site swelling, haemorrhagic blisters, regional lymphadenopathy and coagulopathy were prominent clinical features. Nephrotoxicity and neurotoxicity were notably absent. Clinical features varied depending on the species implicated., (Copyright © 2020 Elsevier Ltd. All rights reserved.)
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- 2021
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14. Comparative Analysis on Dielectric Gold and Aluminium Triangular Junctions: Impact of Ionic Strength and Background Electrolyte by pH Variations.
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Letchumanan I, Md Arshad MK, Gopinath SCB, Rajapaksha RDAA, and Balakrishnan SR
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Field of generating a surface thin film is emerging broadly in sensing applications to obtain the quick and fast results by forming the high-performance sensors. Incorporation of thin film technologies in sensor development for the better sensing could be a promising way to attain the current requirements. This work predominantly delineates the fabrication of the dielectric sensor using two different sensing materials (Gold and Aluminium). Conventional photolithography was carried out using silicon as a base material and the photo mask of the dielectric sensor was designed by AutoCAD software. The physical characterization of the fabricated sensor was done by Scanning Electron Microscope, Atomic Force Microscope, High Power Microscope and 3D-nano profiler. The electrical characterization was performed using Keithley 6487 picoammeter with a linear sweep voltage of 0 to 2 V at 0.01 V step voltage. By pH scouting, I-V measurements on the bare sensor were carried out, whereby the gold electrodes conducts a least current than aluminium dielectrodes. Comparative analysis with pH scouting reveals that gold electrode is suitable under varied ionic strengths and background electrolytes, whereas aluminium electrodes were affected by the extreme acid (pH 1) and alkali (pH 12) solutions.
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- 2020
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15. Sri Lankan green pit viper (Trimeresurus trigonocephalus) bites in Deniyaya: A clinico-epidemiological study.
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Witharana EWRA, Gnanathasan A, Dissanayake AS, Wijesinghe SKJ, Kadahetti SCL, and Rajapaksha RMJK
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- Adolescent, Adult, Aged, Humans, Incidence, Middle Aged, Snake Bites diagnosis, Sri Lanka epidemiology, Crotalid Venoms toxicity, Snake Bites pathology
- Abstract
Green pit viper (Trimeresurus trigonocephalus) is endemic to Sri Lanka and bites are reported from tropical rain forest and plantation areas. As scant data exists on clinico-epidemiological features of Sri Lankan green pit viper bite, objective of this study was to address this knowledge gap. A prospective observational study was conducted in Base Hospital Deniyaya from October 2013 to September 2015. Green pit viper as the offending snake was identified when the victims brought live or dead specimens. When the specimen was not available, green pit viper was identified by the victim pointing to preserved specimens and photographs of green pit viper and different similar appearing snakes. Clinical details were recorded during the hospital stay. Twenty four green pit viper bite patients (17-68 years) were studied. All cases were daytime bites despite green pit viper being a nocturnally active snake. Sixteen patients (67%) were bitten while they were working in tea plantation. Hands (42%), feet, (33%), forearms (8%), legs (8%), thighs (4%) and shoulders (4%) were the sites of bites. Thirteen (54%) had extensive limb swelling. Nine (38%) had local swelling and two had no swelling. Three (12.5%) developed haemorrhagic blisters. Four (17%) had regional lymphadenopathy. Two (8%) developed non clotting blood by the TWBCT. Green pit viper bites caused substantial morbidity. Risk factors included day time outdoor activities in bordering villages of tropical rain forests and occupation. Pain, extensive limb swelling and bite site swelling were prominent clinical features. However haemorrhagic blisters, regional lymphadenopathy and coagulopathy were reported. Nephrotoxicity and neurotoxicity were notably absent., (Copyright © 2019. Published by Elsevier Ltd.)
- Published
- 2019
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16. Voltammetric determination of human papillomavirus 16 DNA by using interdigitated electrodes modified with titanium dioxide nanoparticles.
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Parmin NA, Hashim U, Gopinath SCB, Nadzirah S, Rejali Z, Afzan A, Uda MNA, Hong VC, and Rajapaksha RDAA
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- DNA Probes chemistry, DNA Probes genetics, DNA, Viral genetics, Electrochemical Techniques instrumentation, Electrodes, Female, Humans, Limit of Detection, Nucleic Acid Hybridization, Proof of Concept Study, Reproducibility of Results, Biosensing Techniques methods, DNA, Viral analysis, Electrochemical Techniques methods, Human papillomavirus 16 chemistry, Metal Nanoparticles chemistry, Titanium chemistry
- Abstract
A gene sensor for rapid detection of the Human Papillomavirus 16 (HPV 16) which is associated with the appearance of cervical cancer was developed. The assay is based on voltammetric determination of HPV 16 DNA by using interdigitated electrodes modified with titanium dioxide nanoparticles. Titanium dioxide nanoparticles (NPs) were used to modify a semiconductor-based interdigitated electrode (IDE). The surface of the NPs was then functionalized with a commercial 24-mer oligomer DNA probe for HPV 16 that was modified at the 5' end with a carboxyl group. If the probe interacts with the HPV 16 ssDNA, the current, best measured at a working voltage of 1.0 V, increases. The gene sensor has has a ∼ 0.1 fM limit of detection which is comparable to other sensors. The dielectric voltammetry analysis was carried out from 0 V to 1 V. The electrochemical sensitivity of the IDE is 2.5 × 10
-5 μA·μM-1 ·cm-2 . Graphical abstract Schematic of an interdigitated electrode (IDE) modified with titanium dioxide nanoparticles for voltammetric determination of HPV 16 DNA by using an appropriate DNA probe.- Published
- 2019
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17. Severe Plasmodium vivax malaria, HIV, tuberculosis co-infection in a Sri Lankan traveller: case management and challenges during the prevention of malaria reintroduction phase.
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Ranaweera D, Kanchana Rajapaksha RMJ, Silva P, Hettiarachchi R, Gunasekera WMKTAW, Herath H, and Fernando D
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- Adult, Coinfection diagnosis, Coinfection drug therapy, Communicable Diseases, Imported diagnosis, Communicable Diseases, Imported drug therapy, HIV Infections complications, Humans, Madagascar, Malaria, Vivax complications, Male, Sri Lanka, Travel, Tuberculosis complications, Case Management, HIV Infections diagnosis, HIV Infections drug therapy, Malaria, Vivax diagnosis, Malaria, Vivax drug therapy, Tuberculosis diagnosis, Tuberculosis drug therapy
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Background: The country received malaria-free certification from WHO in September 2016, becoming only the second country in the WHO South East Asia region to be declared malaria-free. Imported malaria cases continue to be reported, with 278 cases reported between 2013 and 2017. The diagnosis of a severe Plasmodium vivax patient co-infected with HIV and tuberculosis is discussed with an overview of the rapid response mounted by the Anti Malaria Campaign (AMC), Sri Lanka., Case Presentation: A Sri Lankan gem miner who returned from Madagascar on the 6th of April 2018 presented to a private hospital for a malaria diagnostic test on the 21st April, 2 days after the onset of fever. He came on his own for this test due to the awareness he had regarding the risk of imported malaria. As the patient was positive for P. vivax malaria, he was admitted to a government hospital for further management. The patient had features of severe malaria upon admission with a systolic BP < 80 mmHg and thrombocytopaenia (38,000 cells/mm
3 ). Treatment with IV artesunate was initiated immediately and management was carried out rapidly and efficiently by the clinicians with guidance from the staff of the AMC headquarters, which resulted in a rapid recovery of the patient. IV artesunate was followed by a course of artemether plus lumefantrine and the blood smear was negative for malaria by the 2nd day. A 14-day course of primaquine was commenced after excluding a G6PD deficiency. Due to an accidental needle stick injury of a health care worker attending on the patient was tested for HIV and subsequently tuberculosis and was found to be positive for both infections. The patient was discharged on the 1st of May with instructions for follow up visits for malaria. Management of the HIV and tuberculosis infections was attended to by the clinicians and staff of the appropriate disease control programmes (i.e. the national STD/AIDS Control Programme in Sri Lanka and the National Programme for tuberculosis control and chest diseases)., Conclusions: It is important to consider comorbid conditions and immunosuppression when a patient with a benign form of malaria presents with severe manifestations. Measures should be strengthened to prevent importation of diseases, such as malaria and AIDS through migrant workers who return from high-risk countries.- Published
- 2018
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18. Biochemical Composition and Expression of Anthocyanin Biosynthetic Genes of a Yellow Peeled and Pinkish Ariled Pomegranate ( Punica granatum L.) Cultivar are Differentially Regulated in Response to Agro-Climatic Conditions.
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Attanayake R, Eeswaran R, Rajapaksha R, Weerakkody P, and Bandaranayake PCG
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- Antioxidants analysis, Antioxidants metabolism, Climate, Fruit genetics, Fruit growth & development, Fruit metabolism, Gene Expression Regulation, Plant, Lythraceae chemistry, Lythraceae growth & development, Lythraceae metabolism, Phenols analysis, Phenols metabolism, Plant Proteins genetics, Plant Proteins metabolism, Anthocyanins biosynthesis, Fruit chemistry, Lythraceae genetics
- Abstract
The accumulation of beneficial biochemical compounds in different parts of pomegranate ( Punica granatum L.) fruit determines fruit quality and highly depends on environmental conditions. We investigated the effects of agro-climatic conditions on major biochemical compounds and on the expression of major anthocyanin biosynthetic genes in the peels and arils of a yellow-peeled and pink-ariled pomegranate cultivar in three agro-climatologically different locations in Sri Lanka. Drier and warmer climates promoted the accumulation of the measured biochemical compounds, i.e. total phenolic content (TPC), antioxidant capacity (AOX), and α, β, and total punicalagin, in both peels and arils compared to wetter and cooler climates. Pomegranate DFR, F3H, and ANS transcripts in both peels and arils showed higher relative expression in hotter and drier regions, compared to those grown in cooler and wetter conditions. Therefore, growing pomegranates in drier and warmer environments maximizes the production of beneficial biochemical compounds and associated gene expression in pomegranate fruit.
- Published
- 2018
- Full Text
- View/download PDF
19. Concurrent methicillin-resistant Staphylococcus aureus septicemia and pyomyositis in a patient with dengue hemorrhagic fever: a case report.
- Author
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Ehelepola NDB, Rajapaksha RKGM, Dhanapala DMUB, Thennekoon TDK, and Ponnamperuma S
- Subjects
- Abscess diagnosis, Abscess microbiology, Adult, Anti-Bacterial Agents therapeutic use, Bacteremia diagnosis, Bacteremia microbiology, Humans, Male, Pyomyositis complications, Pyomyositis microbiology, Sepsis complications, Sepsis microbiology, Severe Dengue complications, Severe Dengue microbiology, Staphylococcal Infections complications, Staphylococcal Infections microbiology, Coinfection diagnosis, Methicillin-Resistant Staphylococcus aureus isolation & purification, Pyomyositis diagnosis, Sepsis diagnosis, Severe Dengue diagnosis, Staphylococcal Infections diagnosis
- Abstract
Background: Concurrent presence of dengue hemorrhagic fever (DHF), tropical pyomyositis and septicemia due to methicillin-resistant Staphylococcus aureus (MRSA) in a previously healthy person has never been reported. These three conditions even individually are potentially fatal. "Here we describe a case of a patient contracting dengue and developing DHF along with concurrent pyomyositis likely to be due to MRSA, leading to MRSA septicemia with abscesses formed by MRSA"., Case Presentation: A 44-year old previously healthy Sinhalese man presented on day 3 of the illness with fever, headache, arthralgia and myalgia and watery loose stools. His pulse rate was 76/min, blood pressure was 110/80 mmHg, while cardiovascular, respiratory and abdomen examination findings were unremarkable. The test for the dengue NS1 antigen was positive on the same day. We have diagnosed dengue and started managing him symptomatically as per the current national guidelines. The patient developed DHF with bilateral pleural effusion and ascitis. On the day 5 he developed severe myalgia, tenderness and non pitting edema of lower limbs especially in the thighs. His creatine kinase levels were high and an ultrasound scan confirmed myositis of both thighs. We suspected myositis due to dengue but investigated for possible simultaneous sepsis as well. On day 9 his blood culture became positive for MRSA. Considering the sensitivity of the bacteria intravenous vancomycin and ciprofloxacin was administered for 21 days. He developed a small abscess at the site of the first intravenous access and a large one above the ankle on the left. On day 12 the latter was drained and the pus culture yielded MRSA sensitive to the same antibiotics. The rapid test for dengue IgM was negative initially but later a positive MAC-ELISA test entrenched dengue infection. After improvement he was sent home on day 33 of the illness. He has developed two other abscesses in the proximity of the drained one and they were drained on day 57. The patient recovered., Conclusions: When dengue patients develop symptoms and signs of myositis, prompt investigations for pyomyositis and the treatment can save lives.
- Published
- 2018
- Full Text
- View/download PDF
20. An in Situ Intracellular Self-Assembly Strategy for Quantitatively and Temporally Monitoring Autophagy.
- Author
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Lin YX, Qiao SL, Wang Y, Zhang RX, An HW, Ma Y, Rajapaksha RP, Qiao ZY, Wang L, and Wang H
- Subjects
- Animals, Cell Line, Tumor, Dose-Response Relationship, Drug, HeLa Cells, Humans, MCF-7 Cells, Oligopeptides chemical synthesis, Oligopeptides chemistry, Temperature, Zebrafish, Autophagy drug effects, Oligopeptides pharmacology
- Abstract
Autophagy plays a crucial role in the metabolic process. So far, conventional methods are incapable of rapid, precise, and real-time monitoring of autophagy in living objects. Herein, we describe an in situ intracellular self-assembly strategy for quantitative and temporal determination of autophagy in living objectives. The intelligent building blocks (DPBP) are composed by a bulky dendrimer as a carrier, a bis(pyrene) derivative (BP) as a signal molecule, and a peptide linker as a responsive unit that can be cleaved by an autophagy-specific enzyme, i.e., ATG4B. DPBP maintains the quenched fluorescence with monomeric BP. However, the responsive peptide is specifically tailored upon activation of autophagy, resulting in self-aggregation of BP residues which emit a 30-fold enhanced fluorescence. By measuring the intensity of fluorescent signal, we are able to quantitatively evaluate the autophagic level. In comparison with traditional techniques, such as TEM, Western blot, and GFP-LC3, the reliability and accuracy of this method are finally validated. We believe this in situ intracellular self-assembly strategy provides a rapid, effective, real-time, and quantitative method for monitoring autophagy in living objects, and it will be a useful tool for autophagy-related fundamental and clinical research.
- Published
- 2017
- Full Text
- View/download PDF
21. Polymeric nanoparticles promote macrophage reversal from M2 to M1 phenotypes in the tumor microenvironment.
- Author
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Wang Y, Lin YX, Qiao SL, An HW, Ma Y, Qiao ZY, Rajapaksha RP, and Wang H
- Subjects
- Animals, Cell Line, Tumor, Cellular Reprogramming drug effects, Cellular Reprogramming immunology, Delayed-Action Preparations administration & dosage, Delayed-Action Preparations chemistry, Female, Interleukin-12 chemistry, Macrophages drug effects, Macrophages pathology, Mice, Mice, Inbred C57BL, Nanocapsules administration & dosage, Nanocapsules ultrastructure, Neoplasms, Experimental pathology, Polymers chemistry, Interleukin-12 administration & dosage, Macrophages immunology, Nanocapsules chemistry, Neoplasms, Experimental drug therapy, Neoplasms, Experimental immunology, Tumor Microenvironment drug effects, Tumor Microenvironment immunology
- Abstract
Immunotherapy has shown promising treatment effects for a variety of cancers. However, the immune treatment efficiency for solid tumors is limited owing to insufficient infiltration of immune cells into solid tumors. The conversion of tumor-supportive macrophages to tumor-suppressive macrophages, inducing the functional reversal of macrophages, is an effective method and contributes to a subsequent antitumor response. The current challenge in the field is the poor distribution and systemic side effects associated with the use of cytokines. As a solution to this issue, we designed and synthesized microenvironment-responsive nanoparticles (P) with IL-12 payload (IL-12⊂P1). These nanoparticles could promote the systemic administration and release of IL-12 in the tumor microenvironment, and the locally responsive property of IL-12⊂P1 could subsequently re-educate tumor-associated macrophages (TAMs). In particular, our results illustrated the great therapeutic effects derived from the functional conversion of macrophages. Our strategy was to design a microenvironment-responsive material for local macrophage modification to overcome the physiological barrier of solid tumors. The shifting of macrophage phenotypes via IL-12⊂P1 achieved immunomodulation in the microenvironment for cancer therapy, with negligible cytotoxicity. We expect that the functional regulation of TAMs by pH-responsive nanomaterials is a promising therapeutic approach for cancer immunotherapy., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2017
- Full Text
- View/download PDF
22. pH-Sensitive Polymeric Nanoparticles Modulate Autophagic Effect via Lysosome Impairment.
- Author
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Lin YX, Wang Y, Qiao SL, An HW, Zhang RX, Qiao ZY, Rajapaksha RP, Wang L, and Wang H
- Subjects
- Cell Survival drug effects, Drug Carriers chemistry, Drug Delivery Systems, Humans, Hydrogen-Ion Concentration, MCF-7 Cells, Autophagy drug effects, Lysosomes chemistry, Nanoparticles chemistry, Polymers chemistry, Polymers pharmacology
- Abstract
In drug delivery systems, pH-sensitive polymers are commonly used as drug carriers, and significant efforts have been devoted to the aspects of controlled delivery and release of drugs. However, few studies address the possible autophagic effects on cells. Here, for the first time, using a fluorescent autophagy-reporting cell line, this study evaluates the autophagy-induced capabilities of four types of pH-sensitive polymeric nanoparticles (NPs) with different physical properties, including size, surface modification, and pH-sensitivity. Based on experimental results, this study concludes that pH-sensitivity is one of the most important factors in autophagy induction. In addition, this study finds that variation of concentration of NPs could cause different autophagic effect, i.e., low concentration of NPs induces autophagy in an mTOR-dependent manner, but high dose of NPs leads to autophagic cell death. Identification of this tunable autophagic effect offers a novel strategy for enhancing therapeutic effect in cancer therapy through modulation of autophagy., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2016
- Full Text
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23. Self-assembled autophagy-inducing polymeric nanoparticles for breast cancer interference in-vivo.
- Author
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Wang Y, Lin YX, Qiao ZY, An HW, Qiao SL, Wang L, Rajapaksha RP, and Wang H
- Subjects
- Acrylates chemistry, Animals, Antineoplastic Agents chemistry, Apoptosis Regulatory Proteins chemistry, Beclin-1, Breast Neoplasms physiopathology, Cell Line, Tumor, Drug Delivery Systems, Humans, Hydrogen-Ion Concentration, Hydrophobic and Hydrophilic Interactions, Lysosomes drug effects, Lysosomes metabolism, Membrane Proteins chemistry, Mice, Nude, Micelles, Nanoparticles chemistry, Neoplasm Transplantation, Polyethylene Glycols chemistry, Polymers chemistry, Protein Stability, Protein Structure, Secondary, Antineoplastic Agents administration & dosage, Apoptosis Regulatory Proteins administration & dosage, Autophagy physiology, Breast Neoplasms drug therapy, Membrane Proteins administration & dosage, Nanoparticles administration & dosage
- Abstract
A peptide-conjugated poly(β-amino ester) that self-assembles into micelle-like nanoparticles is prepared by a convenient and modular supramolecular approach. The polymer-beclin-1 (P-Bec1) nanoparticles display enhanced cytotoxicity to breast cancer cells through induction of autophagy. This approach overcomes two major limitations of the haploinsufficient tumor suppressor Bec1 compared to small-molecule drugs: poor delivery to tumors owing to enzymatic degradation, and unstable, non-specific bio-distribution and targeting in the tumor tissues., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2015
- Full Text
- View/download PDF
24. Clinical study on the effect of decoction of Pavetta indica Linn. in treatment of Purishaja Krimi with special reference to Enterobius vermicularis infestation.
- Author
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Ediriweera ER, Rajapaksha RP, Rathnayaka RL, Premakeerthi WM, and Premathilaka S
- Abstract
Pavetta indica Linn. (Family: Rubiaceae; Sanskrit name: Papata) is 2-5 m tall, shrub or small tree with opposite branches and grows in the Asia - Pacific region including Sri Lanka. Purishaja Krimi is one of the worm infestations described in Ayurveda. Enterobius vermicularis is among the most common of worms affecting children and adults. E. vermicularis is considered as one type of Purishaja Krimi. Sri Lankan traditional and ayurvedic physicians use P. indica to treat different ailments including Purishaja Krimi (E. vermicularis) infestations successfully. Since no scientific studies have been undertaken to study these effects so far, the present clinical study was carried out to evaluate the effect of P. indica in treatment of E. vermicularis infestation. Fifty patients between age of 5 and 12 years (Group A and B) and 50 patients between 13 and 65 years (Group C and D) with symptoms of E. vermicularis infestations such as itching in the anal region, impaired appetite, abdominal pain, eructation, diarrhea or constipation and presence of ova in stools were selected. Two decoction of the trail drug with different concentration was prepared. Group A and Group B were treated with 60 ml of decoction 1 and 60 ml of placebo respectively, twice daily for 14 days. Group C and Group D were treated with 120 ml of decoction 2 and 120 ml of placebo respectively, twice daily for 14 days. Groups A and C showed complete or partial reduction of symptoms, that is; itching in the anal region, impaired appetite, abdominal pain, eructation, diarrhea and also ova of E. vermicularis were absent in stools after treatment with P. indica. Decoction of P. indica can be recommended as an effective treatment for Purishaja Krimi (E. vermicularis infestation).
- Published
- 2013
- Full Text
- View/download PDF
25. Molecular detection and partial characterization of Tomato Yellow Leaf Curl Virus in Sri Lanka.
- Author
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Samarakoon SA, Balasuriya A, Rajapaksha RG, and Wickramarachchi WA
- Subjects
- Base Sequence, Begomovirus classification, DNA Primers, Genes, Viral, Phylogeny, Polymerase Chain Reaction, Sri Lanka, Begomovirus genetics, Solanum lycopersicum virology
- Abstract
Tomato Yellow Leaf Curl Virus (TYLCV) is an important plant virus on one of the economically most important vegetable crops; tomato (Lycopersicon esculentum Mill.). This had not been molecularly detected before, in Sri Lanka. TYLCV-GN-SL was isolated from apparently infected tomato plants using modified Cetyltrimethyl Ammonium Bromide (CTAB) method in Gannoruwa. Associated Begomoviruses were detected using Deng 541/Deng 540 and AV 494/AC 1048 primer pairs. TYLCV was detected for the first time in tomato in Sri Lanka using P1V/P4C, TYLCV specific primer pair. Nucleotide sequence of coat protein of isolated TYLCV-GN-SL proved that the Indian strain of ToLC virus was closely related to Tomato Leaf Curl Sri Lanka Virus (TLCV-SL: 97%) and Tomato leaf curl Geminivirus (TLCGV: 93%) through direct sequencing data. TLCV-SL was confirmed as TYLCV isolate. TYLCV was molecularly detected from major tomato growing districts like Badulla, Nuwara-Eliya, Kandy and Matale in Sri Lanka.
- Published
- 2012
- Full Text
- View/download PDF
26. Sharps injuries among medical students in the Faculty of Medicine, Colombo, Sri Lanka.
- Author
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Liyanage IK, Caldera T, Rwma R, Liyange CK, De Silva P, and Karunathilake IM
- Subjects
- Adult, Female, Humans, Male, Needlestick Injuries etiology, Needlestick Injuries prevention & control, Sri Lanka epidemiology, Surveys and Questionnaires, Needlestick Injuries epidemiology, Occupational Injuries epidemiology, Students, Medical statistics & numerical data
- Abstract
Introduction: Medical students undertake clinical procedures which carry a risk of sharps injuries exposing them to bloodborne infections., Objectives: To study the prevalence and correlates of sharps injuries among 4th-year medical students in the Faculty of Medicine, University of Colombo, Sri Lanka., Materials and Methods: The survey was conducted among 4th-year medical students to find out the incidence of injuries during high-risk procedures, associated factors and practice and perceptions regarding standard precautions. A self-administered questionnaire was administered to a batch of 197 4th-year medical students., Results: A total of 168 medical students responded. One or more injury was experienced by 95% (N = 159) of the students. The majority (89%) occurred during suturing; 23% during venipuncture and 14% while assisting in deliveries. Most of the incidents (49%) occurred during Obstetrics and Gynecology attachments. Recapping needles led to 8.6% of the injuries. Thirty-five percent of students believed they were inadequately protected. In this group, adequate protection was not available in 21% of the incidences and 24% thought protection was not needed. Following the injury, 47% completely ignored the event and only 5.7% followed the accepted post-exposure management. Only 34% of the students knew about post-exposure management at the time of the incident. Only 15% stated that their knowledge regarding prevention and management was adequate. The majority (97%) believed that curriculum should put more emphasis on improving the knowledge and practice regarding sharps injuries., Conclusions: The incidence of sharps injuries was high in this setting. Safer methods of suturing should be taught and practiced. The practice of standard precautions and post-injury management should be taught.
- Published
- 2012
- Full Text
- View/download PDF
27. Nature and bioactivities of endolichenic fungi in Pseudocyphellaria sp., Parmotrema sp. and Usnea sp. at Hakgala montane forest in Sri Lanka.
- Author
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Kannangara BT, Rajapaksha RS, and Paranagama PA
- Subjects
- Antibiosis, Fungi physiology, Sri Lanka, Biodiversity, Fungi isolation & purification, Lichens microbiology, Trees microbiology
- Abstract
Aim: The aim of this study was to investigate the nature and bioactivities of endolichenic fungi in three abundant lichens, Pseudocyphellaria sp., Usnea sp. and Parmotrema sp. in the lower elevation of Hakgala montane forest in Sri Lanka., Methods and Results: Endolichenic fungal strains, fungi that live asymptomatically in the lichen thallus, much the same way as endophytic fungi live within healthy plant tissues, were isolated from three abundant lichen species, Pseudocyphellaria sp., Usnea sp. and Parmotrema sp., at Hakgala montane forest in Sri Lanka, using the surface sterilization method. Nine endolichenic fungal strains were isolated from Parmotrema sp. and Usnea sp. separately, while 11 endolichenic fungi were recovered from the lichen Pseudocyphellaria sp. Isolation of endolichenic fungus Chrysosporium sp. 2 was common to all three lichen species. Substrate utilization patterns and antifungal activities of eight endolichenic fungal species were evaluated and the results revealed that all the test fungi were able to produce at least one enzyme to utilize the test substrates. Nigrospora sp., Chrysosporium sp. 1 and 2 and Cladosporium sp. showed antifungal activities on growth of some selected plant pathogenic fungi., Conclusions: Endolichenic fungal strains (29) were isolated from the lichens Parmotrema sp., Usnea sp. and Pseudocyphellaria sp. in Sri Lanka. Chrysosporium sp. 2 was common in all three lichens. Some of these endolichenic fungal strains showed antifungal activities against common plant pathogenic fungi and they are capable of utilizing the substrates by producing specific enzymes., Significance and Impact of the Study: The diversity and prevalence of the endolichenic fungi have not been studied extensively and this is the first report of isolation and identification of endolichenic fungi in lichens available in Sri Lanka.
- Published
- 2009
- Full Text
- View/download PDF
28. Clear cell odontogenic carcinoma-a case report and review of literature.
- Author
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Siriwardena BS, Tilakaratne WM, and Rajapaksha RM
- Subjects
- Adenocarcinoma, Clear Cell pathology, Cell Nucleus pathology, Cytoplasm pathology, Diagnosis, Differential, Female, Follow-Up Studies, Humans, Keratins analysis, Middle Aged, Mucin-1 analysis, Mandibular Neoplasms pathology, Odontogenic Tumors pathology
- Abstract
The clear cell odontogenic carcinoma (CCOC) is a rare, locally infiltrative neoplasm with a marked tendency for local recurrence and regional lymph node metastasis. The first description in 1985 included three cases of destructive jaw lesions. The entity was described as a clear cell odontogenic tumour in the previous WHO classification due to the fact that rarity of the lesion restricting pathologists to understand the spectrum of the degree of malignancy. These tumours have a peak incidence in the 5th-7th decades. CCOC tends to occur more frequently in the mandible, with a female predilection. The most striking histological feature is of large islands and strands of uniform cells with round or ovoid nuclei and clear cytoplasm. Presently we describe a case of clear cell odontogenic carcinoma in a 52-year-old female who presented with a bony-hard lump in the left body of the mandible. The patient is free of any recurrence after 2 years of follow-up.
- Published
- 2004
- Full Text
- View/download PDF
29. Metal toxicity affects fungal and bacterial activities in soil differently.
- Author
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Rajapaksha RM, Tobor-Kapłon MA, and Bååth E
- Subjects
- Bacteria drug effects, Bacteria growth & development, Biomass, Ecosystem, Fungi drug effects, Fungi growth & development, Hydrogen-Ion Concentration, Soil Pollutants toxicity, Trees, Bacteria metabolism, Copper toxicity, Fungi metabolism, Metals, Heavy toxicity, Soil Microbiology, Zinc toxicity
- Abstract
Although the toxic effect of heavy metals on soil microorganism activity is well known, little is known about the effects on different organism groups. The influence of heavy metal addition on total, bacterial, and fungal activities was therefore studied for up to 60 days in a laboratory experiment using forest soil contaminated with different concentrations of Zn or Cu. The effects of the metals differed between the different activity measurements. During the first week after metal addition, the total activity (respiration rate) decreased by 30% at the highest level of contamination and then remained stable during the 60 days of incubation. The bacterial activity (thymidine incorporation rate) decreased during the first days with the level of metal contamination, resulting in a 90% decrease at the highest level of contamination. Bacterial activity then slowly recovered to values similar to those of the control soil. The recovery was faster when soil pH, which had decreased due to metal addition, was restored to control values by liming. Fungal activity (acetate-in-ergosterol incorporation rate) initially increased with the level of metal contamination, being up to 3 and 7 times higher than that in the control samples during the first week at the highest levels of Zn and Cu addition, respectively. The positive effect of metal addition on fungal activity then decreased, but fungal activity was still higher in contaminated than in control soil after 35 days. This is the first direct evidence that fungal and bacterial activities in soil are differently affected by heavy metals. The different responses of bacteria and fungi to heavy metals were reflected in an increase in the relative fungal/bacterial ratio (estimated using phospholipid fatty acid analysis) with increased metal load.
- Published
- 2004
- Full Text
- View/download PDF
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