Differentiation of human male germ cells from Wharton's jelly-derived mesenchymal stem cells

Dissanayake, DMAB,Patel, H,Wijesinghe, PS The Korean Society for Reproductive Medicine 2018 Clinical and Experimental Reproductive Medicine Vol.45 No.2

Objective: Recapitulation of the spermatogenesis process in vitro is a tool for studying the biology of germ cells, and may lead to promising therapeutic strategies in the future. In this study, we attempted to transdifferentiate Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) into male germ cells using all-trans retinoic acid and Sertoli cell-conditioned medium. Methods: Human WJ-MSCs were propagated by the explant culture method, and cells at the second passage were induced with differentiation medium containing all-trans retinoic acid for 2 weeks. Putative germ cells were cultured with Sertoli cell-conditioned medium at $36^{\circ}C$ for 3 more weeks. Results: The gene expression profile was consistent with the stage-specific development of germ cells. The expression of Oct4 and Plzf (early germ cell markers) was diminished, while Stra8 (a premeiotic marker), Scp3 (a meiotic marker), and Acr and Prm1 (postmeiotic markers) were upregulated during the induction period. In morphological studies, approximately 5% of the cells were secondary spermatocytes that had completed two stages of acrosome formation (the Golgi phase and the cap phase). A few spermatid-like cells that had undergone the initial stage of tail formation were also noted. Conclusion: Human WJ-MSCs can be transdifferentiated into more advanced stages of germ cells by a simple two-step induction protocol using retinoic acid and Sertoli cell-conditioned medium.

Evaluation of vitrification for cryopreservation of teeth

Dissanayake, Surangi C.,Che, Zhong-Min,Choi, Seong-Ho,Lee, Seung-Jong,Kim, Jin Korean Academy of Periodontology 2010 Journal of Periodontal & Implant Science Vol.40 No.3

Purpose: The aim of this study was to investigate whether vitrification in the cryopreservation of periodontal ligament (PDL) cells could be useful for tooth banking. Methods: In step 1, primary cultured human PDL cells were cryopreserved in 100% conventional cryopreservation media and 100% vitrification media (ESF40 media) in different temperatures for 2 weeks. In step 2, a series of modified vitrification formulae named T1 (75% vitrification media + 25% F-media), T2 (50% vitrification media + 50% F-media) and T3 (25% vitrification media + 75% F-media) were used to store PDL cells for 2 weeks and 4 weeks in liquid nitrogen. MTT assay was performed to examine the viability of PDL cells. Results: Maximum cell viability was achieved in cells stored in 100% conventional cryopreservation media at $-196^{\circ}C$ (positive control group) in step 1. Compared to the positive control group, viability of the cells stored in 100% vitrification media was very low as 10% in all test conditions. In step 2, as the percentage of vitrification media decreased, the cell viability increased in cells stored for 2 weeks. In 4-week storage of cells in step 2, higher cell viability was observed in the T2 group than the other vitrification formulae while the positive control group had the highest viability. There was no statistically significant difference in the cell viability of 2-week and 4-week stored cells in the T2 group. Conclusions: These observations indicate 100% vitrification media is not successful in PDL cell cryopreservation. Conventional cryopreservation media is currently the most appropriate media type for this purpose while T2 media would be interesting to test for long-term storage of PDL cells.

The effects of green tea (Camellia sinensis) flower extract on melanin synthesis in B16-F10 melanoma cells

Dissanayake, Chanuri-Yashara,Moon, Hae-Hee,Yang, Kyeong-Mi,Lee, Younjae,Han, Chang-Hoon The Korean Society of Veterinary Science 2018 大韓獸醫學會誌 Vol.58 No.2

The present study observed the effects of a green tea (Camellia sinensis) flower extract (GTFE) on melanin synthesis in B16-F10 melanoma cells. GTFE exhibited antioxidant activity on 2,2-diphenyl-1-picrylhydrazyl and inhibited mushroom tyrosinase activity in a dose-dependent manner. Furthermore, GTFE significantly diminished ${\alpha}-melanocyte$ stimulating hormone (${\alpha}-MSH$) stimulated cellular melanin content and tyrosinase activity throughout the concentration range evaluated. Based on RNA sequencing analysis, differential gene expression patterns observed in ${\alpha}-MSH$ stimulated B16-F10 melanoma cells were normalized by the addition of GTFE. In particular, the expression levels of melanoregulin and tyrosinase genes which are key regulating genes in melanin synthesis were up-regulated by 3.5 and 3 fold respectively by ${\alpha}-MSH$, and were normalized to control levels by the addition of GTFE. The results suggest that GTFE inhibits melanin synthesis in ${\alpha}-MSH$ stimulated B16-F10 melanoma cells by normalizing expression of genes that are essential for melanin synthesis. Overall, the results suggest that GTFE could be applied in the development of a whitening agent for the treatment of dermal hyperpigmentation.

In vitro and in vivo anti-inflammatory properties of high molecular weight sulfated polysaccharides isolated from Sargassum horneri

Dissanayake D.S.,K.K.A Sanjeewa,KyungYuk Ko,Jun-Geun Je,You-Jin Jeon 한국수산과학회 양식분과 2023 한국수산과학회 양식분과 학술대회 Vol.2023 No.6

Diversity and distribution of fauna of the Nasese Shore, Suva, Fiji Islands with reference to existing threats to the biota

Dissanayake Mudiyanselage Suratissa,Upaka Sanjeewa Rathnayake 국립중앙과학관 2016 Journal of Asia-Pacific Biodiversity Vol.9 No.1

Faunal diversity and distribution in the Nasese Shore, Suva, Fiji Islands were studied AprileAugust 2014. The belt transect method was employed to study the species richness and abundance of the fauna. Opportunistic observations were performed to supplement the species richness of the selected habitat types: sandy, rocky and muddy (SRM; Habitat 1); mangrove and sandy (MNS; Habitat 2); muddy and sandy (MS; Habitat 3); and rocky and coral (RC; Habitat 4). Sampling was performed during high and low tide. Faunal density was highest in the RC substrate. The density of mud skippers was significantly higher in the MNS habitat than in the other habitats. This findings could well indicate the environmental pollution levels of this habitat. The ShanoneWeiner Index indicated that the RC habitat possesses the highest diversity, whereas the MS habitat possesses the lowest diversity. In addition, major threats to the biota existed.

Change in intestinal alkaline phosphatase activity is a hallmark of antibiotic-induced intestinal dysbiosis

Dissanayake Wijesooriya Mudhiyanselage Nadeema,Chandanee Malavige Romesha,Lee Sang-Myeong,허정민,이영주 아세아·태평양축산학회 2023 Animal Bioscience Vol.36 No.9

Objective: Intestinal alkaline phosphatase (IAP) maintains intestinal homeostasis by detoxifying bacterial endotoxins and regulating gut microbiota, and lipid absorption. Antibiotics administered to animals can cause gut dysbiosis and barrier disruption affecting animal health. Therefore, the present study sought to investigate the role of IAP in the intestinal environment in dysbiosis. Methods: Young male mice aged 9 weeks were administered a high dose of antibiotics to induce dysbiosis. They were then sacrificed after 4 weeks to collect the serum and intestinal organs. The IAP activity in the ileum and the level of cytokines in the serum samples were measured. Quantitative real-time polymerase chain reaction analysis of RNA from the intestinal samples was performed using primers for tight junction proteins (TJPs) and proinflammatory cytokines. The relative intensity of IAP and toll-like receptor 4 (TLR4) in intestinal samples was evaluated by western blotting. Results: The IAP activity was significantly lower in the ileum samples of the dysbiosisinduced group compared to the control. The interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha concentrations were significantly higher in the ileum samples of the dysbiosis-induced group. The RNA expression levels of TJP2, claudin-3, and claudin-11 showed significantly lower values in the intestinal samples from the dysbiosis-induced mice. Results from western blotting revealed that the intensity of IAP expression was significantly lower in the ileum samples of the dysbiosis-induced group, while the intensity of TLR4 expression was significantly higher compared to that of the control group without dysbiosis. Conclusion: The IAP activity and relative mRNA expression of the TJPs decreased, while the levels of proinflammatory cytokines increased, which can affect intestinal integrity and the function of the intestinal epithelial cells. This suggests that IAP is involved in mediating the intestinal environment in dysbiosis induced by antibiotics and is an enzyme that can potentially be used to maintain the intestinal environment in animal health care.

Performance Comparison of HEVC and H.264/AVC Standards in Broadcasting Environments

Dissanayake, Maheshi B.,Abeyrathna, Dilanga L.B. Korea Information Processing Society 2015 Journal of information processing systems Vol.11 No.3

High Efficiency Video Coding (HEVC) is the most recent video codec standard of the ITU-T Video Coding Experts Group and the ISO/IEC Moving Picture Experts Group. The main goal of this newly introduced standard is for catering to high-resolution video in low bandwidth environments with a higher compression ratio. This paper provides a performance comparison between HEVC and H.264/AVC video compression standards in terms of objective quality, delay, and complexity in the broadcasting environment. The experimental investigation was carried out using six test sequences in the random access configuration of the HEVC test model (HM), the HEVC reference software. This was also carried out in similar configuration settings of the Joint Scalable Video Module (JSVM), the official scalable H.264/AVC reference implementation, running on a single layer mode. According to the results obtained, the HM achieves more than double the compression ratio compared to that of JSVM and delivers the same video quality at half the bitrate. Yet, the HM encodes two times slower (at most) than JSVM. Hence, it can be concluded that the application scenarios of HM and JSVM should be judiciously selected considering the availability of system resources. For instance, HM is not suitable for low delay applications, but it can be used effectively in low bandwidth environments.

Retrofitting of damaged bridges – the sustainable solution

Ranjith Dissanayake,Chaminda S. Bandara 서울시립대학교 도시과학연구원 2016 도시과학국제저널 Vol.20 No.2

Rehabilitation of damaged bridges may be more beneficial than building new bridges. However, proper methods are necessary to assess the level of damages and to verify the fitness of such bridges for further use. In the assessment, there are two important criteria to consider. One is the amount of damage due to fatigue caused by usual past vehicle loading and the other is the magnitude of damage caused by the unexpected actions. The present paper is about a wrought iron bridge damaged by floods. In order to do the assessment, a condition survey was first carried out. Then an analysis was done using a finite element model of the bridge. The model was validated using results of a field loading test. Both static and dynamic loading tests were conducted using a locomotive with six numbers of 13.16-ton axles for five different loading cases to measure the displacement, strain and acceleration at predetermined (critical) members of the bridge. Then the damage in the bridge due to past loading histories and the future fatigue life of the bridge were estimated. Furthermore, using the validated model, the ability of the bridge for higher loading situations was confirmed. The future life was found as 30 years with a factor of safety of 3. The cost estimated for retrofitting work and constructing new reinforced concrete abutments was much less than that for constructing a new bridge. Therefore, it was decided that the rehabilitation of the bridge with necessary retrofitting work is more economical and sustainable than demolishing it and constructing a new one. The bridge is now in use after being repaired, retrofitted and placed on new abutments.

Effect of Animal Manure with and without Chemical Fertilizer on Dragon Fruit (hylocereus Undatus(haw.) Britton & Rose) Cultivation in the Low Country Intermediate Zone of Sri Lanka

Priyanga Dissanayake,Hemantha Wijewardena,Ajith Kumarasinghe,Nimal Gunaratne 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Evaluation of vitrification for cryopreservation of teeth

Surangi C. Dissanayake,최정민,최성호,이승종,김진 대한치주과학회 2010 Journal of Periodontal & Implant Science Vol.40 No.3

Purpose: The aim of this study was to investigate whether vitrification in the cryopreservation of periodontal ligament (PDL)cells could be useful for tooth banking. Methods: In step 1, primary cultured human PDL cells were cryopreserved in 100% conventional cryopreservation media and 100% vitrification media (ESF40 media) in different temperatures for 2 weeks. In step 2, a series of modified vitrification formulae named T1 (75% vitrification media + 25% F media), T2 (50% vitrification media + 50% F media) and T3 (25% vitrification media + 75% F media) were used to store PDL cells for 2 weeks and 4 weeks in liquid nitrogen. MTT assay was performed to examine the viability of PDL cells. Results: Maximum cell viability was achieved in cells stored in 100% conventional cryopreservation media at -196°C (positive control group) in step 1. Compared to the positive control group, viability of the cells stored in 100% vitrification media was very low as 10% in all test conditions. In step 2, as the percentage of vitrification media decreased, the cell viability increased in cells stored for 2 weeks. In 4-week storage of cells in step 2, higher cell viability was observed in the T2 group than the other vitrification formulae while the positive control group had the highest viability. There was no statistically significant difference in the cell viability of 2-week and 4-week stored cells in the T2 group. Conclusions: These observations indicate 100% vitrification media is not successful in PDL cell cryopreservation. Conventional cryopreservation media is currently the most appropriate media type for this purpose while T2 media would be interesting to test for long-term storage of PDL cells.