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U n i v e r s i t y of P e r a d e n i y a

The Institutional Repository of the University of Peradeniya is the University's digital gateway to scholarly knowledge and research excellence. Established as the next phase of the Digital Library initiative launched by the University Library in 2011, it preserves, showcases, and provides open access to the intellectual output of the University community.

Through a rich collection of research articles, conference proceedings, theses, dissertations, and other scholarly works, the repository enhances the visibility, accessibility, and long-term preservation of knowledge, extending the global reach and impact of the University of Peradeniya’s academic and research contributions.

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Antioxidant activity of some green tea constituents
(The University of Peradeniya, 2003-10-23) Kumar, N. S.; Rajapaksha, K. T. P. M. P.
Tea is unique in having a high concentration of flavanoids (catechins) that have been associated with the health benefits of tea. Catechins are polyphenolic compounds, and are known to be strong anti-oxidants that may help to protect the body from free radical damage. The results of recent scientific and medical studies suggest that tea drinking helps to reduce the risk of certain types of cancer and cardiovascular diseases. In the present study, the antioxidant activity of crude catechin extracts and green tea constituents obtained after fractionation by High Speed Countercurrent Chromatography (HSCCC) was determined using the β-carotene bleaching method and the DPPH (α,α- diphenyl-β-picrylhydrazyl) radical scavenging method using α-tocopherol (Vitamin E) and BRA (butylated hydroxyanisole) respectively, as reference compounds. Antioxidant activity of tea constituents was determined by a modified version of the β-carotene bleaching method, and was observed to decrease in the order, FLA2 (469.0) > FLAl (431.0) > epigallocatechin gallate EGCG (329.3) > epicatechin gallate ECG (280.0) > epigallocatechin EGC (201.0) > epicatechin gallate EC (151.0) > theobromine TB (74). Both BHA (680.0) and α-tocopherol (551.5) were stronger anti-oxidants than the tea constituents. In this method, the anti-oxidant coefficient of a sample is calculated. The difference in the anti-oxidant coefficients of the catechin samples with respect to a control sample is an indication of the inhibition of the coupled oxidation of linoleic acid and β-carotene by oxygen, and is measured by the absorption due to β-carotene at 470 nm. Antioxidant activity of tea constituents determined using the DPPH radical scavenging method decreased in the order ECG (90.8) > EGCG (90.0) > FLA2 (87.0) > FLAl (76.3) > EGC (58.9) > EC (36.8) > TB (35.3). In this method, the decrease in absorbance of the DPPH radical (DPPHo ) due to its reduction by different antioxidants was measured. According to this method, BRA showed less antioxidant activity than ECG, EGCG and a-tocopherol. Additionally, EGCG and ECG were found to be equally potent in hydrogen donating ability than BHA. Both methods confirm the strong anti-oxidant activity of green tea catechins. The unidentified catechins, FLAl and FLA2, are also potent anti-oxidants. Studies to establish the structures of these two compounds are in progress.
Effect of Oral Habits of Patients on the Overexpression of EGFR Protein in Oral Squamous Cell Carcinomas (OSCCS)
(University of Peradeniya, Sri Lanka, 2005-11-10) Dissanayake, U.; Amaratunga, E. A. P. D.; Dissanayake, D. M.
Over activation of a growth promoting proto-oncogene such as epidermal growth factor receptor (EGFR) plays a major role in the development of epithelial malignancies. It has been shown that alteration in the gene due to long term exposure to various carcinogenic agents is the reason for this. Betel chewing, smoking and consumption of alcohol are recognized risk factors for development of OSCCs. Both epidemiological and laboratory studies have revealed that the long-term exposure to such ingredients' which carry different carcinogenic agents results in malignant transformation, The aim of the present study was to observe the relationship between the frequency of different habits in patients with OSCCs and immuno-expression ofEGFR protein in their carcinomas. The sample consisted of 60 primary OSCC patients (males). Information on oral habits was recorded. Patients were stratified according to the severity of smoking, frequency of betel chewing and amount of alcohol consumption (mild = 1, moderate = 2, heavy = 3, habit free = 0). Over-expression of EGFR was assessed by immunohistochemistry using monoclonal antibody EGFR 113 (dil, 1:20, Novocastra). The percentage of positive cells, and the intensity (+, ++, +++) of expression were recorded. Analysis was done using chi square test. In the sample 86.6 % of the patients were betel chewers. Out of sixty, 62 % were smokers and 60 % consumed alcohol. EGFR positivity was 56 %. Over 50 % of the cancer cells were EGFR positive in 10/34 positive tumours. No significant difference was found in the over-expression of EGFR in 0SCCs, either between smokers I and non-smokers or between betel chewers and non-betel chewers. Intensity of EGFR expression in OSCCs was not significant both between smokers and non-smokers or chewers and non-chewers. There was a significant difference in the percentage of EGFR positive cells between heavy consumers of alcohol and mild to moderate consumers of alcohol «X2 = 19.4, P = 0.004). Intensity of EGFR protein expression also significantly differed between heavy consumers of alcohol and mild to moderate consumers of alcohol (X2 = 12.5, P = 0.05). No association was found between smoking, betel chewing and EGFR immunoreactivity in the present sample. However, exposure to alcohol showed a significant increase in the protein expression. Further studies are needed to confirm the over-expression of EGFR in oral squamous cell carcinomas induced by alcohol.
Oral-health-related knowledge, attitudes and oral-care practices of nursing undergraduates of Faculty of Allied Health Sciences, University of Peradeniya, Sri Lanka
(University of Peradeniya, Sri Lanka, 2021-11-11) Bandara, D. L.; Weerasinghe, G.K.; Pushpakumara, P.H.G.J.
As primary caregivers, it is important to establish adequate knowledge and a better attitude towards oral care in nursing officers. This study aimed to assess the oral health knowledge, attitude and oral-care practices among nursing undergraduates of the Faculty of Allied Health Sciences, University of Peradeniya, Sri Lanka. A cross-sectional analytical study was carried out in March 2019.Self-reported knowledge, attitude and oral-care practices of all students were assessed using a pre-tested self-administered questionnaire. Oral-health-related knowledge was evaluated under six sub scales. The majority of the participants were females, 109/148(73.65%). The highest mean score for knowledge was on dental plaque 7.16 (SD 4.5) while the lowest was on oral cancers, 3.89 (SD 3.13). However, nearly one-third of the undergraduates (37.84%) were not aware of the main purpose of tooth brushing. A positive attitude towards oral health was reported by 45 (30.41%, 95% CI 22.3-38.5%) undergraduates. Nevertheless, the distribution of the scores for the knowledge and attitude was not statistically different between gender and among different academic year of study.80% (n=118) of undergraduates brushed twice a day and 72% (n=107) used fluoridated toothpastes. Slightly more than half of the undergraduates (53.4%, 95% CI 44.6-62.2%) had snacks in between main meals while 41.9% (95% CI 33.3-50.6%) had maintained regular dental visits. Although a majority showed good oral practices, a significant percentage was not aware of the main purpose of tooth brushing. Similarly, the knowledge on oral cancer, which is a highly prevalent condition in Sri Lanka, was not satisfactory. No difference was found in scores of knowledge and attitude on oral health between genders or among academic year of study. Thus, suggest further studies and incorporation of properly designed oral health education programmes for the nursing undergraduates.
Evaluation of demographic and clinical characteristics of oral submucous fibrosis in a group of Sri Lankan patients – a retrospective cohort study
(University of Peradeniya, Sri Lanka, 2021-11-11) Hettiarachchi, P.V.K.S.; Anupama, S.; Jayasinghe, R.D.
Oral submucous fibrosis (OSF) is a well-established oral potentially malignant disorder (OPMD) that affects the South Asian countries including Sri Lanka where the traditional habit of areca nut chewing prevails. The aim of this study was to evaluate the demographic and clinical characteristics of OSF among patients presented to the Faculty of Dental Sciences, University of Peradeniya. A retrospective cohort of 503 patients, diagnosed with OSF, followed up in the Oral Medicine clinic, for the past 22 years were included in the study. Patients‘ age ranging from 3 - 81 years (394 males (78.3%) and 109 females (21.6%); mean age, 43.38 years) with the diagnosis of OSF presented to Oral Medicine clinic. The main complaint of the patients presented was burning sensation (45.1). Fifty six patients complained either of an ulcer or a white/red patch. Majority, 69.8% had the habit of betel chewing only, while 14 had chewing areca nut alone as their risk factor and 18.1% had the synergistic habit of betel chewing and smoking. 65.4 % had the involvement of the buccal mucosa with the presence of fibrous bands on the initial visit with 28.4% demonstrating restricted tongue movements. The commonest abnormality observed on the tongue was depapillation (55.7%) and de- pigmentation, an early feature noted in 27.2%. A total of 463 patients had undergone a histopathological investigation and almost 50% of those were devoid of any dysplastic lesions. According to the grading system by Kerr et al. (2011), 39% of cases were at Grade 4B, that is OSF with any grade of dysplasia in the biopsy at the initial presentation and only 16% presented with mild disease (Grade 1). The clinical characteristics of OSF patients may differ due to variations in risk habits practiced.
Gender classification and prediction using eruption status of permanent teeth in Sri Lankan children
(University of Peradeniya, Sri Lanka, 2021-11-11) De Silva, B.D.H.H.; Nawarathna, L.S.; Vithanaarachchi, V.S.N.
Gender prediction is a dominant component in forensic identification procedures. Teeth are better preserved than other parts of the human body, resistant to high temperature and any mass disaster, thereby providing the best records for forensic investigations. Moreover, tooth eruption is a process that teeth enter the mouth and become visible and eruption status is a measure that can be taken at low cost and efficiency. Hence, this study was undertaken to predict the gender using the eruption status of permanent teeth. Although many studies have been done based on different measures of teeth, this is a novel study for Sri Lankan children using eruption status of permanent teeth. This cross- sectional study was carried out on 3321 children with 1681 males and 1640 females from 7 provinces and 20 schools. A tooth was considered erupted, if more than 1/3ʳᵈ of the crown is visible and recorded as status 1. Gender is a binary variable and all 28 predictor variables (permanent teeth) are also binary variables with status 1 or 0.Therefore a classification based approach was used to predict the gender of a child using machine learning classifiers, namely Classification and Regression Tree (CART), Random Forest and Extreme Gradient Boosting (XG Boost) which are non-parametric and based on decision trees. The fitted models were validated using 10-fold cross-validation technique and the model performance was measured using accuracy, F1 score, sensitivity and specificity. The Extreme Gradient Boosting classifier was selected as the best performance model compared to the other fitted models which are performed with the highest accuracy 62.80% and 0.6340 F1 score. Hence, the gender of a child can be predicted using the best-fitted model in situations as forensic investigations. Furthermore, gathering data covering all the districts in Sri Lanka would enhance the performance of the proposed classifier for gender prediction.