Browsing by Author "de Silva, R."

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Apoferritin and Dps as drug delivery vehicles: Some selected examples in oncology
(Elsevier Ltd, 2022) Kuruppu, A.I.; Turyanska, L.; Bradshaw, T.D.; Manickam, S.; Galhena, B.P.; Paranagama, P.; de Silva, R.
Background: The ideal nanoparticle should be able to encapsulate either pharmaceutical agents or imaging probes so that it could treat or image clinical tumours by targeting the cancer site efficiently. Further, it would be an added advantage if it demonstrates: small size, built in targeting, biocompatibility and biodegradability. Ferritin, which is an endogenous self-assembling protein, stores iron and plays a role in iron homeostasis. When iron atoms are removed apoferritin (AFt) is formed which consists of a hollow shell where it can be used to load guest molecules. Due to its unique architecture, AFt has been investigated as a versatile carrier for tumour theranostic applications. DNA-binding protein from starved cells (Dps), which also belongs to the ferritin family, is a protein found only in prokaryotes. It is used to store iron and protect chromosomes from oxidative damage; because of its architecture, Dps could also be used as a delivery vehicle. Conclusions: Both these nano particles are promising in the field of oncology, especially due to their stability, solubility and biocompatibility features. Further their exterior surface can be modified for better tumour-targeting ability. More studies, are warranted to determine the immunogenicity, biodistribution, and clearance from the body. General perspective: This review discusses a few selected examples of the remarkable in vitro and in vivo studies that have been carried out in the recent past with the use of AFt and Dps in targeting and delivery of various pharmaceutical agents, natural products and imaging probes in the field of oncology.
Cross-cultural adaptation and validation of the Leibowitz Social Anxiety Scale (LSAS-SR) sinhala version
(Sri Lanka Medical Association, 2020) Hapangama, A.; Kuruppuarachchi, L. A.; de Silva, R.; Wickremasinghe, A.R.; Ravindran, A.; Williams, S. S.
No abstract available
Diagnosis of Vespa affinis venom allergy:use of immunochemical methods and a passive basophil activation test
(Allergy, Asthma & Clinical Immunology, 2019) Gunasekara, P.; Handunnetti, S.M.; Premawansa, S.; Kaluarachchi, P.; Karunatilake, C.; Ratnayake, I.P.; Dias, R. K. S.; Premakumara, G. A. S.; Dasanayake, W. M. D. K.; Seneviratne, S.L.; de Silva, R.
Background: Allergy to Vespa affinis venom is common in the Asia Pacific region. Venom preparations for diagnosis are not commercially available for this species. Methods: The prominent allergens in V. affinis venom were identifiedusing immunochemical methods. Use of ImmunoCAP of Vespula vulgaris crude venom/its components and a passive basophil activation test (BAT) in the diagnosis of patients who had anaphylaxis to V. affinis venom (n = 30) were also accessed. The IgE double-positivity rates (positive to both hornet and honeybee) in ImmunoCAP and the passive BAT were determined. Results: High IgE reactivity was seen with the five allergens in V. affinis venom; 96% (29/30) for 34 and 24 kDa, 93% (28/30) for 45 kDa and 90% (27/30) reactivity for the 100 and 80 kDa respectively. IgE cross-reactivity was low with ImmunoCAP using V. vulgaris venom (43%; 13/30) and Ves v1 (3%; 1/30), but relatively high with Ves v5 (73%; 22/30). All patients (100%) were positive to V. affinis venom in passive BAT. In ImmunoCAP, a high double-positivity rate (76%; 23/30) was detected while no double-positivity was detected in passive BAT. Conclusions: High IgE reactivity for five allergens of V. affinis points to the potential of using these allergens in component resolved diagnosis (CRD). The passive BAT has shown its importance as a promising diagnostic tool with high accuracy. It would be particularly useful in cases with doubtful double-positive results of other diagnostic tests.
Effect of antimicrobial agents on inflammatory cytokines in acute Leptospirosis
(American Society for Microbiology, 2018) Fernando, N.; de Silva, R.; Hadunnetti, S.M.; Karunanayake, L.; de Silva, N.L.; de Silva, H.J.; Rajapakse, S.; Premawansa, S.
The aim of this study was to assess the inflammatory cytokine response and possible association with antimicrobial treatment with penicillin, ceftriaxone, and doxycycline in acute leptospirosis. In the early acute stage, interleukin-10 (IL-10) levels were higher in mild cases than in severe cases (P = 0.01). IL-6 and IL-8 levels were low in patients who received >5 antimicrobial doses (P < 0.01). IL-8 levels were negatively correlated with the number of ceftriaxone doses administered (r = -0.315; P = 0.031). Further studies are needed to evaluate the possible downregulation of proinflammatory cytokines by ceftriaxone in leptospirosis.
Gender recognition of Luffa flowers using machine learning
(International Research Conference on Smart Computing and Systems Engineering - SCSE 2018, 2018) Gunasinghe, H.N.; de Silva, R.
Automatic flower gender identification could be introduced to large farmlands to help artificial pollination of imperfect flowers. Incomplete flowers contain either male or female organs but not both. In this paper, we present a computer aided system based on image processing and machine learning to identify the gender of a Luffa flower automatically. A pre-trained machine learning model is used for gender segmentation of flowers. The system is developed using Tensorflow Machine Learning Tool, which is an open-source software library for Machine Intelligence. The network was selected as the Google’s Inception model and a dataset was prepared after capturing flower images from a Sri Lankan Luffa farm. The system was tested using two datasets. The first contained the captured original images and the second was prepared by cropping each image to extract male and female floral organs, stamen and pistil respectively. The prototype system classified the flowers as either male or female at 95% accuracy level. The experimental results indicate that the proposed approach can significantly support an accurate identification of the gender of a Luffa flower with some computational effort.
Identification of water stressed leaves using Artificial Intelligence: The case of eggplant
(International Research Conference on Smart Computing and Systems Engineering - SCSE 2018, 2018) Senanayake, P.A.; de Silva, R.
Identification of water stress of leaves from the photos taken has a long history. Researchers have defined a parameter called Leaf Water Content (LWC) to quantify the dryness of leaves. However, in the case of automatic watering of plants, such high accuracy of LWC is not needed as a decision to water or not alone is sufficient. Furthermore, the agricultural industry cannot use methods of remote sensing that are required to find LWC as they are complex and costly. In the current practice, farmers use their knowledge and experience together with the appearance of plants to estimate the water stress and watering time point of plants. The approach presented in this paper is easily implemented and requires only a series of photos taken by a smartphone or a camera and a software app. In this paper, a method s introduced using Artificial Intelligence (AI) where the images of leaves are directly used to determine whether the leaves are water stressed. We could identify the water stressed leaves accurately using this method. Once an app based on our method is developed, it could easily be used by farmers to automatically identify whether the eggplants are water stressed and need watering.
Knowledge and practices regarding COVID-19 preventive measures among the patients admitted to a general medical ward
(Faculty of Medicine, University of Kelaniya, Sri Lanka, 2021) de Silva, R.; Wanigasuriya, R.; Marasinghe, C.
Introduction: COVID 19 has developed into a global pandemic. Sri Lanka experiencing a major outbreak claiming many lives. Ministry of Health with other collaborators introduced precautions to be followed by the public. These included the proper wearing of masks, good hand hygiene, and social distancing. Objectives: To assess the knowledge and practices regarding COVID-19 preventive measures among patients admitted to a general medical ward. Methods: A descriptive cross-sectional study was done at the University Medical Unit of Colombo South Teaching Hospital from May - July 2021. An interviewer-administered questionnaire was used to collect data. Results: The study sample was 70 (55.7% males), with a mean age of 52.81 years (SD - 17.22). Of them, 47.1% were educated up to O/L and 44.3% up to A/L. More than half (57.1%) were employed and 78.6% had received at least one COVID 19 vaccine. Out of the seven questions on knowledge about covid-19, 77.1% scored 7/7, 20% scored 6/7, and the rest scored 5/6. Majority (98.6%) wore masks in public places and 25.7% experienced breathing difficulties. Out of the 12 steps of proper wearing masks, 4.3% followed all, 37.1% followed 9-11 and 52.9% followed 6-8 steps. For hand hygiene, 94.3% used soap and water and 40% used alcohol rub. Social distancing was maintained by 80.3%. Conclusion: Patients admitted to the general medical ward had good knowledge about COVID 19. Although most patients wear masks, proper technique is not followed by the majority. People attempt to keep good hand hygiene but social distancing is sub-optimal.
Pluriactivity and Socio-economic Success of Rural Households
(University of Kelaniya, 2005) de Silva, R.; Kodithuwakku, S.S.
Despite the efforts made to alleviate poverty, it is further escalating. The past few decades have seen a transformation in Sri Lanka from a traditional agricultural based rural economy to a more diversified economy trying to move away from total dependence on agriculture. The policy focus has also been changed towards improving household income with the realization of higher success among pluriactive households, but whether pluriactivity alone will pave the path for success remain unanswered in the Sri Lankan context. Therefore, the objective of this research is to look into the differences between better off and worse off pluriactive households in terms of entrepreneurial skills and type of income generation activities carried out. Research was done in line with entrepreneurial theory and multiple embedded case study approach was adopted as it facilitates exploring meanings attached to particular behavious and how these are linked and accommodate usage of multiple research methods. The behaviour patterns of households shaped by the limited resource environment in which they operate, thus everybody was pluriactive due to unprofitability and uncertainty in crop cultivation. Better-off households were different from worse-off households in terms of other income generation activities adopted and dependency on crop cultivation as a source of income. Worse-off households had not at least utilized their own resources optimally and in contrast better-off households had utilized resources, which were not under their control, through pluriactivity, social network and creativity by exhibiting entrepreneurial qualities. The research further illustrates that worse-off households had benefited from better-off households thus contributing to economic wealth and rural development. The research findings illustrate the importance of shifting the policy focus from macro level to micro level by being sensitive to heterogeneity observed among rural households.
Randomized controlled trial evaluating the effectiveness of cognitive behaviour group therapy (CBGT) compared to a waitlist control in the treatment of university students with social anxiety disorder
(Postgraduate Institute of Medicine University of Colombo, 2021) Hapangama, A.; de Silva, R.; Williams, S.S.; de Zoysa, P.T.; Wickremasinghe, R.R.; Kuruppuarachchi, K.A.L.A.; Ravindran, A.
BACKGROUND: Social anxiety disorder (SAD) is a common mental illness that causes significant functional impairment. Individually delivered cognitive behavioural therapy (CBT) is an effective but costly intervention with limited access, and is poorly scalable to meet the need in the population. In this context, cognitive behavioural group therapy (CBGT) is a more viable option. OBJECTIVE: To determine the effectiveness of CBGT as compared to a waitlist control for university students with SAD. METHODS: A single-blind randomized controlled trial consisting of an 8-week treatment of CBGT (N=15) versus a waitlist control (N=15) was conducted in university students meeting Diagnostic and Statistical Manual 5 criteria for SAD. The Liebowitz Social Anxiety Scale –Self Rated Sinhala version (LSAS-SR) was administered at screening, baseline, four weeks and eight weeks of the trial. Manualized and Culturally adopted CBGT was delivered in Sinhala language, to the intervention group by a licensed clinical psychologist. RESULTS: The mean age of the study population was 22 (SD=1.345) and baseline mean LSAS-SR score was 72.33 in the experimental arm and 69.03 in the wait list control. Repeated measures analysis revealed that the mean total score of the LSAS-SR in the CBGT arm was significantly lower (13.262; p<0.001) post-intervention compared to the waitlist group after controlling for age and gender. CONCLUSION: Culturally adapted CBGT in Sinhala for SAD is effective in ameliorating social anxiety symptoms among university students. KEYWORDS: social phobia, social anxiety disorder, cognitive behaviour group therapy, sri Lanka