26 results on '"De Silva SS"'
Search Results
2. Epithelial and stromal metabolite changes in the transition from cervical intraepithelial neoplasia to cervical cancer: an in vivo 1H magnetic resonance spectroscopic imaging study with ex vivo correlation.
- Author
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De Silva SS, Payne GS, Morgan VA, Ind TE, Shepherd JH, Barton DP, Desouza NM, De Silva, Sonali S, Payne, Geoffrey S, Morgan, Veronica A, Ind, Thomas E J, Shepherd, John H, Barton, Desmond P J, and deSouza, Nandita M
- Abstract
To investigate epithelial and stromal metabolite changes in cervical intraepithelial neoplasia (CIN) and cervical cancer in vivo and correlate findings with MR spectroscopy of tissue samples. Forty-seven women (19 with CIN, 28 with cervical cancer) underwent endovaginal MR at 1.5 T with T2-W and localised 2D MR spectroscopic imaging (PRESS, TR = 1,500 ms, TE = 135 ms). tCho, 2 ppm and -CH(2) lipid peaks were measured in epithelial (>50% epithelium, no tumour), stromal (>50% stroma, no tumour) and tumour (>30% tumour) voxels. Unsuppressed water signal from the same voxel provided a concentration reference. (1)H HR-MAS MR spectra were acquired from tissue in 37 patients (11.74 T, pulse-acquire and cpmg sequences, with water pre-saturation). Analysable data from 17 CIN and 25 cancer patients showed significant increases in tCho (p = 0.03) and 2 ppm (p = 0.007) in tumour compared with epithelial voxels from CIN patients, but not with epithelial voxels from cancer patients. No significant differences were seen in stroma from cancer compared with CIN patients. Differences in -CH(2) lipids were not significant between groups. There was no significant correlation between in vivo and ex vivo tCho or -CH(2) lipids. Estimated in vivo concentrations of tCho and 2 ppm resonances increase in tumour and adjacent epithelium in progression from CIN to cervical cancer. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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3. Diffusion-weighted imaging in cervical cancer with an endovaginal technique: potential value for improving tumor detection in stage Ia and Ib1 disease.
- Author
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Charles-Edwards EM, Messiou C, Morgan VA, De Silva SS, McWhinney NA, Katesmark M, Attygalle AD, DeSouza NM, Charles-Edwards, Elizabeth M, Messiou, Christina, Morgan, Veronica A, De Silva, Sonali S, McWhinney, Norman A, Katesmark, Mike, Attygalle, Ayoma D, and DeSouza, Nandita M
- Published
- 2008
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4. An evaluation of the method used in digestibility estimations of a dietary ingredient and comparisons on external and internal markers, and time of faeces collection in digestibility studies in the fish Oreochromis aureus (Steindachner)
- Author
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De Silva, SS, primary, Shim, KF, additional, and Khim Ong, A., additional
- Published
- 1990
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5. A GIS based approach to neighbourhood physical environment and walking among adults in Colombo municipal council area, Sri Lanka.
- Author
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Weliange SS, Fernando D, Withanage S, and Gunatilake J
- Subjects
- Adult, Cross-Sectional Studies, Environment Design, Humans, Residence Characteristics, Sri Lanka, Geographic Information Systems, Walking
- Abstract
Background: Physical Activity (PA) promotes health and wellbeing and walking is one of the easiest and commonest way to incorporate activity into everyday life. This study examined the association between the objectively measured neighbourhood physical environment and walking among the adults in Colombo Municipal Council (CMC) area in Sri Lanka., Methods: A cross sectional study was carried out and primary data collection carried out to assess walking, socio-demographic characteristics and geo location of residence. Secondary data was obtained to assess neighbourhood environment from existing spatially referenced data from the survey department of Sri Lanka. Geographic Information Systems (GIS) was used to calculate density measures (residential density, land use, connectivity and access) and distance measures, which were then correlated with walking., Results: A sample consisted of 284 adults aged 29-59 years with a mean age of 40.6 (SD,10.9) years. The total mean minutes walked a week was 175.8 min with a standard deviation of 214.0. The mean and the standard deviations of walking per week for transportation and leisure were 158.4 (SD,196.6) and 17.5 (SD,70.1) respectively. Residential density measures, building foot print area, length of major roads, number of intersections, number of bus stops, and distance to nearest major roads showed significant moderate degree of correlations with total minutes of walked per week, (p < 0.001). These results were similar with walking for transportation., Conclusion: There is indication that neighbourhood features are associated with walking among the adults in the CMC area using secondary data on physical environment. This paves way for further exploration to understand the relationship between neighbourhood physical environment and walking which could be used for effective interventions to promote walking.
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- 2021
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6. Paradigm changes in freshwater aquaculture practices in China: Moving towards achieving environmental integrity and sustainability.
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Wang Q, Li Z, Gui JF, Liu J, Ye S, Yuan J, and De Silva SS
- Subjects
- Animals, China, Fishes, Fresh Water, Aquaculture, Fisheries, Food Supply
- Abstract
Contribution of fisheries and aquaculture to global food security is linked to increased fish consumption. Projections indicate that an additional 30-40 million tonnes of fish will be required by 2030. China leads global aquaculture production accounting for 60% in volume and 45% in value. Many changes in the Chinese aquaculture sector are occurring to strive towards attaining environmental integrity and prudent use of resources. We focus on changes introduced in freshwater aquaculture developments in China, the main source of food fish supplies. We bring forth evidence in support of the contention that Chinese freshwater aquaculture sector has introduced major paradigm changes such as prohibition of fertilisation in large water bodies, introduction of stringent standards on nutrients in effluent and encouragement of practices that strip nutrients among others, which will facilitate long-term sustainability of the sector.
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- 2018
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7. Sustainable farming practices of the Chinese mitten crab (Eriocheir sinensis) around Hongze Lake, lower Yangtze River Basin, China.
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Wang Q, Liu J, Zhang S, Lian Y, Ding H, Du X, Li Z, and De Silva SS
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- Animals, Aquaculture economics, China, Cost-Benefit Analysis, Diet, Lakes, Plants, Water Quality, Water Supply, Aquaculture methods, Brachyura, Conservation of Natural Resources
- Abstract
Results of a survey of 156 Chinese mitten crab (Eriocheir sinensis) grow-out farms around Hongze Lake (118.48-118.72°E; 33.36-33.38°N) are reported. Area farmed has remained relatively unchanged but production (59 932 t in 2012) increased steadily over the last 7 years, indicative of the viability and sustainability of the farming system that has gradually replaced intensive Chinese major carp polyculture around Hongze Lake. Results showed that production range was 135-2400 kg ha(-1) cycle(-1) (mean 1144 ± 34). Crab yields correlated linearly to stocking density and conformed to a normal distribution curve, with 66.7 % of farms yielding 900 kg ha(-1) cycle(-1) or more. Yield was negatively correlated to pond size and capture size (p < 0.01), and farms with macrophyte coverage rate lower than 30 % of water surface were significantly (p < 0.05) lower than those exceeding 30 %.
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- 2016
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8. Exploring the climate change concerns of striped catfish producers in the Mekong Delta, Vietnam.
- Author
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Nguyen AL, Truong MH, Verreth JA, Leemans R, Bosma RH, and De Silva SS
- Abstract
This study investigated the perceptions on and adaptations to climate change impacts of 235 pangasius farmers in the Mekong Delta, Vietnam. Data were collected using semi-structured household surveys in six provinces, from three regions along the Mekong river branches. A Chi-Square test was used to determine the association between variables, and a logit regression model was employed to identify factors correlated with farmer's perception and adaptation. Less than half of respondents were concerned about climate change and sought suitable adaptation measures to alleviate its impacts. Improving information on climate change and introducing early warning systems could improve the adaptive capacity of pangasius farmers, in particularly for those farmers, who were not concerned yet. Farmers relied strongly on technical support from government agencies, but farmers in the coastal provinces did not express the need for training by these institutions. This contrasting result requires further assessment of the effectiveness of adaptation measures such as breeding salinity tolerant pangasius.
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- 2015
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9. Simulated impacts of climate change on current farming locations of striped catfish (Pangasianodon hypophthalmus; Sauvage) in the Mekong Delta, Vietnam.
- Author
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Nguyen AL, Dang VH, Bosma RH, Verreth JA, Leemans R, and De Silva SS
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- Animals, Salinity, Vietnam, Aquaculture, Catfishes, Climate Change
- Abstract
In Vietnam, culturing striped catfish makes an important contribution to the Mekong Delta's economy. Water level rise during rainy season and salt intrusion during dry season affect the water exchange and quality for this culture. Sea level rise as a consequence of climate change will worsen these influences. In this study, water level rise and salt water intrusion for three sea level rise (SLR) scenarios (i.e., +30, +50, and +75 cm) were simulated. The results showed that at SLR +50, the 3-m-flood level would spread downstream and threaten farms located in AnGiang, DongThap and CanTho provinces. Rising salinity levels for SLR +75 would reduce the window appropriate for the culture in SocTrang and BenTre provinces, and in TienGiang's coastal districts. Next to increasing dikes to reduce the impacts, the most tenable and least disruptive option to the farming community would be to shift to a salinity tolerant strain of catfish.
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- 2014
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10. n-3 LC-PUFA deposition efficiency and appetite-regulating hormones are modulated by the dietary lipid source during rainbow trout grow-out and finishing periods.
- Author
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Francis DS, Thanuthong T, Senadheera SP, Paolucci M, Coccia E, De Silva SS, and Turchini GM
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- Animal Feed analysis, Animals, Diet, Fatty Acids chemistry, Fatty Acids metabolism, Fish Oils administration & dosage, Fish Oils pharmacokinetics, Fish Proteins blood, Fisheries, Leptin blood, Plant Oils administration & dosage, Plant Oils pharmacokinetics, Dietary Fats, Unsaturated administration & dosage, Dietary Fats, Unsaturated pharmacokinetics, Fatty Acids, Omega-3 administration & dosage, Fatty Acids, Omega-3 pharmacokinetics, Ghrelin blood, Oncorhynchus mykiss growth & development, Oncorhynchus mykiss physiology
- Abstract
Largely attributable to concerns surrounding sustainability, the utilisation of omega-3 long-chain polyunsaturated fatty acid-rich (n-3 LC-PUFA) fish oils in aquafeeds for farmed fish species is an increasingly concerning issue. Therefore, strategies to maximise the deposition efficiency of these key health beneficial fatty acids are being investigated. The present study examined the effects of four vegetable-based dietary lipid sources (linseed, olive, palm and sunflower oil) on the deposition efficiency of n-3 LC-PUFA and the circulating blood plasma concentrations of the appetite-regulating hormones, leptin and ghrelin, during the grow-out and finishing phases in rainbow trout culture. Minimal detrimental effects were noted in fish performance; however, major modifications were apparent in tissue fatty acid compositions, which generally reflected that of the diet. These modifications diminished somewhat following the fish oil finishing phase, but longer-lasting effects remained evident. The fatty acid composition of the alternative oils was demonstrated to have a modulatory effect on the deposition efficiency of n-3 LC-PUFA and on the key endocrine hormones involved in appetite regulation, growth and feed intake during both the grow-out and finishing phases. In particular, n-6 PUFA (sunflower oil diet) appeared to 'spare' the catabolism of n-3 LC-PUFA and, as such, resulted in the highest retention of these fatty acids, ultimately highlighting new nutritional approaches to maximise the maintenance of the qualitative benefits of fish oils when they are used in feeds for aquaculture species.
- Published
- 2014
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11. Estimation of nitrogen and phosphorus in effluent from the striped catfish farming sector in the Mekong Delta, Vietnam.
- Author
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De Silva SS, Ingram BA, Nguyen PT, Bui TM, Gooley GJ, and Turchini GM
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- Animals, Rivers, Vietnam, Aquaculture, Catfishes, Nitrogen analysis, Phosphorus analysis, Water Pollution analysis
- Abstract
In this study an attempt is made to estimate nitrogen and phosphorus discharged to the environment from the striped catfish (Pangasianodon hypophthalmus) farming sector in the Mekong Delta (8 degrees 33'-10 degrees 55' N, 104 degrees 30'-106 degrees 50' E), South Vietnam. The sector accounted for 687,000 t production in 2007 and 1,094,879 t in 2008, with over 95% of the produce destined for export to over 100 countries. Commercial and farm-made feeds are used in catfish farming, currently the former being more predominant. Nitrogen discharge levels were similar for commercial feeds (median 46.0 kg/t fish) and farm-made feeds (median 46.8 kg/t fish); whilst, phosphorus discharge levels for commercial feeds (median 14.4 kg/t fish) were considerably lower than for farm-made feeds (median 18.4 kg/t fish). Based on the median nutrient discharge levels for commercial feeds, striped catfish production in the Mekong Delta discharged 31,602 t N and 9,893 t P, and 50,364 t N and 15,766 t P in 2007 and 2008, respectively. However, the amount of nutrients returned directly to the Mekong River may be substantially less than this as a significant proportion of the water used for catfish farming as well as the sludge is diverted to other agricultural farming systems. Striped catfish farming in the Mekong Delta compared favourably with other cultured species, irrespective of the type of feed used, when the total amounts of N and P discharged in the production of a tonne of production was estimated.
- Published
- 2010
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12. Detection of cancer in cervical tissue biopsies using mobile lipid resonances measured with diffusion-weighted (1)H magnetic resonance spectroscopy.
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Zietkowski D, Davidson RL, Eykyn TR, De Silva SS, Desouza NM, and Payne GS
- Subjects
- Cervix Uteri chemistry, Female, Humans, ROC Curve, Biopsy, Cervix Uteri pathology, Diffusion Magnetic Resonance Imaging methods, Lipids analysis, Uterine Cervical Neoplasms diagnosis, Uterine Cervical Neoplasms pathology
- Abstract
The purpose of this study was to implement a diffusion-weighted sequence for visualisation of mobile lipid resonances (MLR) using high resolution magic angle spinning (HR-MAS) (1)H MRS and to evaluate its use in establishing differences between tissues from patients with cervical carcinoma that contain cancer from those that do not. A stimulated echo sequence with bipolar gradients was modified to allow T(1) and T(2) measurements and optimised by recording signal loss in HR-MAS spectra as a function of gradient strength in model lipids and tissues. Diffusion coefficients, T(1) and apparent T(2) relaxation times were measured in model lipid systems. MLR profiles were characterised in relation to T(1) and apparent T(2) relaxation in human cervical cancer tissue samples. Diffusion-weighted (DW) spectra of cervical biopsies were quantified and peak areas analysed using linear discriminant analysis (LDA). The optimised sequence reduced spectral overlap by suppressing signals originating from low molecular weight metabolites and non-lipid contributions. Significantly improved MLR visualisation allowed visualisation of peaks at 0.9, 1.3, 1.6, 2.0, 2.3, 2.8, 4.3 and 5.3 ppm. MLR analysis of DW spectra showed at least six peaks arising from saturated and unsaturated lipids and those arising from triglycerides. Significant differences in samples containing histologically confirmed cancer were seen for peaks at 0.9 (p < 0.006), 1.3 (p < 0.04), 2.0 (p < 0.03), 2.8 (p < 0.003) and 4.3 ppm (p < 0.0002). LDA analysis of MLR peaks from DW spectra almost completely separated two clusters of cervical biopsies (cancer, 'no-cancer'), reflecting underlying differences in MLR composition. Generated Receiver Operating Characteristic (ROC) curves and calculated area under the curve (0.962) validated high sensitivity and specificity of the technique. Diffusion-weighting of HR-MAS spectroscopic sequences is a useful method for characterising MLR in cancer tissues and displays an accumulation of lipids arising during tumourigenesis and an increase in the unsaturated lipid and triglyceride peaks with respect to saturated MLR., (Copyright © 2009 John Wiley & Sons, Ltd.)
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- 2010
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13. Diffusion weighted imaging of the uterus: regional ADC variation with oral contraceptive usage and comparison with cervical cancer.
- Author
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Messiou C, Morgan VA, De Silva SS, Ind TE, and deSouza NM
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- Adult, Female, Humans, Prospective Studies, Uterus drug effects, Young Adult, Contraceptives, Oral administration & dosage, Diffusion Magnetic Resonance Imaging methods, Uterine Cervical Neoplasms diagnosis, Uterine Cervical Neoplasms pathology, Uterus pathology
- Abstract
Background: There is growing interest in diffusion weighted magnetic resonance imaging (MRI) of cervical carcinoma but normal uterine appearances and effects of the oral contraceptive pill (OCP) have not been described., Purpose: To establish apparent diffusion coefficient (ADC) values for normal regions of uterus, determine the effect of the OCP on these values, and compare them with ADCs from cervical cancer., Material and Methods: Twenty-seven premenopausal women (19 taking the OCP) with cervical intraepithelial neoplasia (CIN) were studied with T2W and diffusion weighted MRI (DW-MRI). Regions of interest were drawn on ADC maps by visual matching with T2W images on different zones of the uterus and values compared between women not taking and taking the OCP. A further group of 25 women with clinically obvious tumors of the cervix were also studied with T2W and DW-MRI and ADC values of tumor were compared with ADC values of cervical epithelium and stroma., Results: The ADC values of adjacent zones of the uterus and cervix were significantly different from one another (P<0.001). The junctional zone was seen as a band of restricted diffusion between endometrium and outer myometrium. The ADC value of the junctional zone of the uterus was significantly greater (P<0.001) in patients taking the OCP than those patients not taking the OCP. There was no significant affect of the OCP on the ADC values of other uterine zones., Conclusion: The zonal anatomy of the uterus is well demonstrated by DW-MRI with hormonal effects secondary to the OCP affecting junctional zone alone. ADC of cervical tumor is significantly different to cervical epithelium and stroma indicating a role in cervical cancer detection and local staging.
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- 2009
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14. Trace metal concentrations in Nile tilapia (Oreochromis niloticus) in three catchments, Sri Lanka.
- Author
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Allinson G, Salzman SA, Turoczy N, Nishikawa M, Amarasinghe US, Nirbadha KG, and De Silva SS
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- Animals, Liver chemistry, Muscles chemistry, Sensitivity and Specificity, Spectrophotometry, Atomic, Sri Lanka, Metals analysis, Tilapia, Trace Elements analysis
- Abstract
Samples of the muscle and liver of the Nile tilapia (Oreochromis niloticus) were obtained from a single reservoir in each of three Sri Lankan catchments (Kaudulla, Rajanganaya, and Udawalawe reservoirs in the Mahaweli, Kala Oya, and Walawe Ganga river basins, respectively) in 2002. The concentrations of 12 elements were consistently detected in the tilapia muscle and liver (Ca, Cd, Cu, Fe, Hg, K, Mg, Mn, Na, P, Sr and Zn). However, a three factorial principal components analysis suggested that there were no differences in the metal profiles (range of elements and concentration) of the fish obtained from any of the three reservoirs, although the chemistries of each tissue (muscle and liver) were different. Metal concentrations were below WHO and Food Standards Australia and New Zealand guideline values, and substantial quantities of tilapia would need to be consumed each week on a regular basis to exceed intake limits (e.g. more than 1.5 kg to exceed intake lits for Cu), suggesting consumption of tilapia from these reservoirs poses little risk to human health.
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- 2009
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15. Alien species in aquaculture and biodiversity: a paradox in food production.
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De Silva SS, Nguyen TT, Turchini GM, Amarasinghe US, and Abery NW
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- Animals, Asia, Conservation of Natural Resources, Fresh Water, Population Dynamics, Aquaculture methods, Biodiversity, Fishes physiology
- Abstract
Aquaculture is seen as an alternative to meeting the widening gap in global rising demand and decreasing supply for aquatic food products. Asia, the epicenter of the global aquaculture industry, accounts for over 90% of the global aquaculture production quantity and about 80% of the value. Asian aquaculture, as with global aquaculture, is dependent to a significant extent on alien species, as is the case for all the major food crops and husbanded terrestrial animals. However, voluntary and or accidental introduction of exotic aquatic species (alien species) is known to negatively impact local biodiversity. In this relatively young food production industry, mitigating the dependence on alien species, and thereby minimizing potential negative impacts on biodiversity, is an imperative for a sustainable future. In this context an attempt is made in this synthesis to understand such phenomena, especially with reference to Asian inland finfish, the mainstay of global aquaculture production. It is pointed out that there is potential for aquaculture, which is becoming an increasingly important food production process, not to follow the past path of terrestrial food crops and husbanded animals in regard to their negative influences on biodiversity.
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- 2009
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16. Investigation of metabolite changes in the transition from pre-invasive to invasive cervical cancer measured using (1)H and (31)P magic angle spinning MRS of intact tissue.
- Author
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De Silva SS, Payne GS, Thomas V, Carter PG, Ind TE, and deSouza NM
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- Adult, Aged, Female, Humans, Middle Aged, Neoplasm Invasiveness, Phosphorus Isotopes analysis, Spin Labels, Young Adult, Biomarkers, Tumor analysis, Biomarkers, Tumor metabolism, Magnetic Resonance Spectroscopy methods, Uterine Cervical Neoplasms metabolism, Uterine Cervical Neoplasms pathology
- Abstract
The aim of this study was to determine the metabolic changes in the transition from pre-invasive to invasive cervical cancer using high-resolution magic angle spinning (HR-MAS) MRS. Biopsy specimens were obtained from women with histologically normal cervix (n = 5), cervical intraepithelial neoplasia (CIN; mild, n = 5; moderate/severe, n = 40), and invasive cancer (n = 23). (1)H HR-MAS MRS data were acquired using a Bruker Avance 11.74 T spectrometer (Carr-Purcell-Meiboom-Gill sequence; TR = 4.8 s; TE = 135 ms; 512 scans; 41 min acquisition). (31)P HR-MAS spectra were obtained from the normal subjects and cancer patients only (as acetic acid applied before tissue sampling in patients with CIN impaired spectral quality) using a (1)H-decoupled pulse-acquire sequence (TR = 2.82 s; 2048 scans; 96 min acquisition). Peak assignments were based on values reported in the literature. Peak areas were measured using the AMARES algorithm. Estimated metabolite concentrations were compared between patient diagnostic categories and tissue histology using independent samples t tests. Comparisons based on patient category at diagnosis showed significantly higher estimated concentrations of choline (P = 0.0001) and phosphocholine (P = 0.002) in tissue from patients with cancer than from patients with high-grade dyskaryosis, but no differences between non-cancer groups. Division by histology of the sample also showed increases in choline (P = 0.002) and phosphocholine (P = 0.002) in cancer compared with high-grade CIN tissue. Phosphoethanolamine was increased in cancer compared with normal tissue (P = 0.0001). Estimated concentrations of alanine (P = 0.01) and creatine (P = 0.008) were significantly reduced in normal tissue from cancer patients compared with normal tissue from non-cancer patients. The estimated concentration of choline was significantly increased in CIN tissue from cancer patients compared with CIN tissue from non-cancer patients (P = 0.0001). Estimated concentrations of choline-containing metabolites increased from pre-invasive to invasive cervical cancer. Concurrent metabolite depletion occurs in normal tissue adjacent to cancer tissue., (Copyright (c) 2008 John Wiley & Sons, Ltd.)
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- 2009
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17. Effects of starvation and water quality on the purging process of farmed Murray cod (Maccullochella peelii peelii).
- Author
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Palmeri G, Turchini GM, Keast R, Marriott PJ, Morrison P, and De Silva SS
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- Animals, Fatty Acids analysis, Gastrointestinal Tract, Lipids analysis, Meat analysis, Taste, Aquaculture methods, Food Deprivation, Gadiformes growth & development, Water chemistry
- Abstract
The aim of this study was to determine the effects of starvation and water quality during the purging process on the biometric parameters, fatty acids, and flavor volatiles of Murray cod farmed in a recirculation system. Market size Murray cod, at the end of the grow-out stage, were divided into eight treatments. The treatments were either fed/starved (F or S) and kept in clean water (CW: CWF2, CWS2, CWF4, and CWS4) or fed/starved and kept in recycled water (RW: RWF2, RWS2, RWF4, and RWS4) for either 2 or 4 weeks. Fish were sampled at 0, 2, and 4 week intervals. Food deprivation was responsible for a significant (P < 0.05) weight loss compared to that of fed treatments. The same was observed for the condition factor (K), hepatosomatic index (HSI), and dress-out percentage (DP). No significant changes were, however, observed in the visceral fat index (VFI). Saturated fatty acids (SFA) were highest in RWF4 and lowest in CWS4 (P < 0.05), while monounsaturated fatty acids (MUFA) were lowest in CWF4 (P < 0.05). Starvation did not affect the flavor volatile compounds, which were mainly affected by changes in water quality. Specifically, total aldehyde (% w/w) content was significantly (P < 0.05) affected by water quality, but the time of purging was not responsible for any noteworthy differences. This study was able to separate the effects of starvation and water quality, in the purging process, on the final eating quality of farmed market size Murray cod. It is concluded that because of the inevitable weight loss during starvation, Murray cod should be fed during the purging stage but kept in clean water and deprived of food only for the time necessary to empty the gastro-intestinal tract.
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- 2008
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18. A whole body, in vivo, fatty acid balance method to quantify PUFA metabolism (desaturation, elongation and beta-oxidation).
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Turchini GM, Francis DS, and De Silva SS
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- Acetyltransferases metabolism, Animals, Delta-5 Fatty Acid Desaturase, Diet, Fatty Acid Desaturases metabolism, Fatty Acid Elongases, Fatty Acids analysis, Homeostasis, Linoleoyl-CoA Desaturase metabolism, Oxidation-Reduction, Oxidoreductases metabolism, Fatty Acids metabolism, Fatty Acids, Unsaturated metabolism
- Abstract
Currently there are several contrasting methods utilized for estimating elongation and desaturation of fatty acids and their general metabolism. The majority of these methods involve an ex vivo approach, requiring expensive and sophisticated equipment, likely to result in considerable variation in enzyme activity between and within species. In the present paper we introduce a further development of the whole-body fatty acid balance method for the estimation of the elongation and desaturation of fatty acids. This method though receiving considerable attention because of its simplicity and reliability has yet to be presented in detail. Theoretically, the whole-body fatty acid balance method can potentially be applied to any organism and requires little more than a gas chromatography unit for fatty acid analysis and elementary calculations. As such in this paper we attempt to spell out in detail the theoretical basis and the methods of application drawing specific examples. Using the present method it is possible to measure the fate of individual fatty acids towards desaturation, elongation and oxidation and calculate the elongase, Delta-6 desaturase and Delta-5 desaturase activities.
- Published
- 2007
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19. Analog parallel processing of molecular sensory information.
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de Silva AP, de Silva SS, Goonesekera NC, Gunaratne HQ, Lynch PL, Nesbitt KR, Patuwathavithana ST, and Ramyalal NL
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- 2007
- Full Text
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20. Dietary lipid source modulates in vivo fatty acid metabolism in the freshwater fish, Murray cod (Maccullochella peelii peelii).
- Author
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Francis DS, Turchini GM, Jones PL, and De Silva SS
- Subjects
- Acetyltransferases metabolism, Animals, Fatty Acid Elongases, Fatty Acids, Omega-3 administration & dosage, Fatty Acids, Omega-6 administration & dosage, Fish Oils administration & dosage, Linoleoyl-CoA Desaturase metabolism, Plant Oils administration & dosage, Dietary Fats pharmacology, Fatty Acids metabolism, Perciformes metabolism
- Abstract
The aim of the present investigation was to quantify the fate of C18 and long chain polyunsaturated dietary fatty acids in the freshwater fish, Murray cod, using the in vivo, whole-body fatty acid balance method. Juvenile Murray cod were fed one of five iso-nitrogenous, iso-energetic, semipurified experimental diets in which the dietary fish oil (FO) was replaced (0, 25, 50, 75, and 100%) with a blended vegetable oil (VO), specifically formulated to match the major fatty acid classes [saturated fatty acids, monounsaturated fatty acids, n-3 polyunsaturated fatty acids (PUFA), and n-6 PUFA] of cod liver oil (FO). However, the PUFA fraction of the VO was dominated by C18 fatty acids, while C20/22 fatty acids were prevalent in the FO PUFA fraction. Generally, there was a clear reflection of the dietary fatty acid composition across each of the five treatments in the carcass, fillet, and liver. Lipid metabolism was affected by the modification of the dietary lipid source. The desaturation and elongation of C18 PUFAs increased with vegetable oil substitution, supported by the occurrence of longer and higher desaturated homologous fatty acids. However, increased elongase and desaturase activity is unlikely to fulfill the gap observed in fatty acid composition resulting from decreased highly unsaturated fatty acids intake.
- Published
- 2007
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21. The assembly of rotaxane-like dye/cyclodextrin/surface complexes on aluminium trihydroxide or goethite.
- Author
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Cooper RJ, Camp PJ, Gordon RJ, Henderson DK, Henry DC, McNab H, De Silva SS, Tackley D, Tasker PA, and Wight P
- Abstract
Simple azo-dyes carrying phosphonic acid and arsonic acid substituents such as 4-(4-hydroxyphenyl azo)phenylphosphonic acid (5) and 4-(4-hydroxyphenylazo)phenylarsonic acid (6) bind more strongly to high surface area oxides such as aluminium trihydroxide and goethite than their carboxylic and sulfonic acid analogues and the phosphonate-functionalized dyes have been shown to have greater humidity fastness when printed onto commercial alumina-coated papers. Adsorption isotherm measurements provide evidence for the formation of ternary dye/cyclodextrin/surface complexes. Dyes which form such ternary complexes show higher light fastness when printed onto alumina coated papers in an ink formulation containing alpha-cyclodextrin.
- Published
- 2006
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22. Fatty acid metabolism in the freshwater fish Murray cod (Maccullochella peelii peelii) deduced by the whole-body fatty acid balance method.
- Author
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Turchini GM, Francis DS, and De Silva SS
- Subjects
- Animals, Dietary Fats administration & dosage, Energy Metabolism, Fatty Acids, Monounsaturated administration & dosage, Fatty Acids, Unsaturated analysis, Linoleic Acid metabolism, Linoleoyl-CoA Desaturase metabolism, Linseed Oil administration & dosage, Oleic Acid metabolism, Rapeseed Oil, Dietary Fats pharmacology, Fatty Acids metabolism, Fatty Acids, Unsaturated metabolism, Perciformes metabolism
- Abstract
The whole-body fatty acid balance method was used to investigate the fatty acid metabolism in Murray cod (Maccullochella peelii peelii) fed diets containing canola (CO) or linseed oil (LO). Murray cod were able to elongate and desaturate both 18:2n-6 and 18:3n-3. In fish fed the CO diet, 54.4% of the 18:2n-6 consumed was accumulated, 38.5% oxidized and 6.4% elongated and desaturated to higher homologs. Fish fed the LO diet accumulated 52.9%, oxidized 37% and elongated and desaturated 8.6% of the consumed 18:3n-3. The overall roles of n-6 fatty acids appeared more important in Murray cod compared to other freshwater species. Murray cod also showed a preferential order of utilization of C18 fatty acid for energy production (18:3n-3 > 18:2n-6 > 18:1n-9). Moreover, it is demonstrated that an increase in dietary 18:3n-3 is directly responsible of increased desaturase activity and augmented saturated fatty acid accumulation in the fish body. The present study also suggests that, in the context of the possible maximization of the natural ability of fish to produce long chain polyunsaturated fatty acids, the whole-body approach can be considered well suited and informative and Murray cod is a suited candidate to fish oil replacement for its diets.
- Published
- 2006
- Full Text
- View/download PDF
23. Attachment of phosphonate-functionalised azo-dyes to oxide surfaces to give enhanced light and wet fastness.
- Author
-
De Silva SS, Camp PJ, Henderson DK, Henry DC, McNab H, Tasker PA, and Wight P
- Subjects
- Adsorption, Azo Compounds chemical synthesis, Coloring Agents chemical synthesis, Light, Organophosphonates chemical synthesis, Oxides chemical synthesis, Wettability, Azo Compounds pharmacokinetics, Coloring Agents pharmacokinetics, Organophosphonates pharmacokinetics, Oxides pharmacokinetics
- Abstract
Phosphonate-functionalised dyes have been shown to bind strongly to aluminium oxides and to form stable 1:1 complexes with cyclodextrins at the surface.
- Published
- 2003
- Full Text
- View/download PDF
24. Observations on metal concentrations in tilapia (Oreochromis mossambicus) in reservoirs of south Sri Lanka.
- Author
-
Allinson G, Nishikawa M, De Silva SS, Laurenson LJ, and De Silva K
- Subjects
- Animals, Environmental Monitoring, Fresh Water, Liver chemistry, Liver metabolism, Metals analysis, Muscle, Skeletal chemistry, Muscle, Skeletal metabolism, Principal Component Analysis, Sri Lanka, Fisheries, Metals metabolism, Tilapia metabolism
- Abstract
Samples of the muscle and liver of tilapia (Oreochromis mossambicus) obtained from the five reservoirs in four catchments in southern Sri Lanka in 1998 were analyzed for 16 elements: As, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, and Zn by inductively coupled plasma emission spectrophotometry, and Hg by atomic absorption spectrophotometry. The concentrations of Cr, Ni, and Pb were below the detection limits of the instrumental techniques employed in all samples. The elements As, Ca, Co, Cu, Fe, Hg, K, Mg, Mn, Na, Sr, and Zn were detected in the muscle and liver tissue, with Cd detected in some liver samples. There were no statistically significant differences between the individual concentrations of any of the metals and the site from which the tilapia were collected (P>0.05). Furthermore, no statistically significant correlations were found between total length of fish and metal concentration. No elements were found at concentrations of toxicological concern. However, a principal component analysis suggests that the populations of tilapia in the reservoirs may be exposed to different regimes of metals, possibly associated with different catchment land-use patterns., ((c) 2002 Elsevier Science (USA).)
- Published
- 2002
- Full Text
- View/download PDF
25. Girls' relational self in Sri Lanka and the United States.
- Author
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Stiles DA, Gibbons JL, and de Silva SS
- Subjects
- Adolescent, Age Factors, Child, Cross-Cultural Comparison, Culture, Female, Humans, Self-Assessment, Sri Lanka, United States, Self Concept
- Abstract
The self-conceptions of 100 girls (11-17 years old) from Sri Lanka and the United States were studied from the traditional Western perspective of identity development as a process in which adolescents become increasingly independent and autonomous. This perspective is based on male development in Western countries and may not adequately describe the experience of girls of non-Western adolescents, for whom relationships with others may be central to identity formation. The participating girls drew self-portraits and either answered the question "How would you describe yourself to yourself?" or completed the sentence "I am..." 20 times. The results indicate that relationships and independence are important themes for the girls from the United States and from Sri Lanka. Older girls differed from younger girls in that greater maturity was associated with greater interest in interpersonal relationships and future lives.
- Published
- 1996
- Full Text
- View/download PDF
26. [Rise in knowledge and contact with drugs in 1st grade students of public and private schools in Ribeirao Preto].
- Author
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Ferriani M das G, Cano MA, Spagnol CA, Moreira SC, and de Silva SS
- Subjects
- Brazil epidemiology, Child, Health Surveys, Humans, Social Class, Health Knowledge, Attitudes, Practice, Illicit Drugs, Students psychology, Substance-Related Disorders epidemiology
- Abstract
This study was made to determine contact with drugs among first-grade students from public and private schools in the Riberao Preto community. The various social classes were considered. We decided to use the concept of social status for out empiric research, which defines it as a group of persons who have a certain number of characteristics in common which can be measured, that is, common status, and which may be defined by different criteria. Schools were classified according to their pupils, and after this initial classification, they were divided into 4 groups. A school was selected by lots from each group. A questionnaire with open and closed questions was used as instrument for data collection. According to the collected data, it was concluded that all pupils, independently from their social and economic level, had a superficial knowledge on drugs: 48.2% of those surveyed said they knew people in their neighbourhood who used drugs; 8.8% referred that they had been offered drugs. Drugs offered to them included; cocaine, marijuana, hashish, cigarettes and toxic pencils. The other 63% referred that nobody had given them any advice regarding drugs.
- Published
- 1994
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