Sub-organism (acetylcholinesterase activity), population (survival) and chemical concentration responses reinforce mechanisms of antagonism associated with malathion toxicity.

Within human modified ecosystems the effects of individual stressors are difficult to establish amid co-occurring biological processes, environmental gradients and other stressors. Coupled examination of several endpoints across different levels of organisation may help elucidate the individual and combined effects of stressors and interactions. Malathion is a commonly used organophosphate pesticide that contaminates freshwaters and has strong negative effects on aquatic biota. However, both other stressors (e.g. increased sediment) and common ecosystem components (e.g. macrophytes and variable pH) can reduce the aqueous concentrations of malathion, reducing its toxic effects. We conducted a fully orthogonal bioassay to examine how pH (at 7 and 7.8) and sorptive processes (across two levels of kaoline clay 0 and 24 g L-1) affected aqueous malathion concentrations and toxicity in an aquatic invertebrate genus. Survival and acetylcholinesterase activity as a sub-organism response were examined in the mayfly Coloburiscoides spp. (Ephemeroptera; Coluburiscidae). Measured aqueous malathion concentrations decreased with increased pH and in the presence of kaolin clay. Survival declined with increasing malathion concentrations and exposure period. Results further identify that antagonism of malathion toxicity was associated with both pH (alkaline hydrolysis) and effects associated with sediment independent of pH (driven by sorptive processes). However, model predictions varied associated with target and measured concentrations and concentrations examined. Antagonistic effects were most apparent using subset target malathion concentrations because of the dominant effect of malathion at high concentrations. Acetylcholinesterase activity, identified repression occurred across all treatments and did not identify antagonistic interactions, but these results were similar to survival responses at the time points examined (i.e. 120 h). Examination of chemistry, acetylcholinesterase, and survival, affords greater understanding of stressor effects and their interactions. Measured malathion concentrations may underestimate effects on aquatic biota; not because of synergism among stressors, but because of strong effects despite antagonism.

Dehydration and malaria augment the risk of developing chronic kidney disease in Sri Lanka.

Chronic kidney disease (CKD) of unknown etiology (CKDu) is a serious health issue in Sri Lanka. One-to-one age and sex-matched two sample comparative study was carried out in the Medawachchiya divisional secretariat area of the North Central Province (NCP) of Sri Lanka, by randomly selecting 100 CKDu patients and 100 age and sex-matched subjects from non-CKDu affected families from the same area. An interviewer-administered questionnaire was used for the collection of data pertaining to occupation, medical history and lifestyle. Data were analyzed using a conditional linear logistic model. Working for >6 h in the field per day, exposure to sun, drinking water only from well, consumption of <3 L of water per day, and having a history of malaria were found to be having significant (P < 0.05) likelihood toward the development of CKDu. Treatment of water prior to consumption had a significant protective effect against CKDu. Dehydration, history of malaria and drinking untreated well water from are likely contribute to the development of CKD of unknown etiology among the inhabitants of NCP, Sri Lanka.

Effects of bisphenol A and fadrozole exposures on cyp19a1 expression in the Murray rainbowfish, Melanotaenia fluviatilis.

Several endocrine-disrupting chemicals (EDCs) have been attributed to the alteration of reproduction in fish through disrupting endogenous sex steroidogenic pathways including aromatisation of androgens to oestrogen by CYP19 aromatase. Here we investigate this hypothesis in adult male and female Melanotaenia fluviatilis by examining the mRNA expression of cyp19a1 isoforms after exposure for ≤96 h to two EDCs with contrasting modes of action: one a weak oestrogen mimic, bisphenol A [BPA (100 or 500 µg/L)], and the other a nonsteroidal aromatase inhibitor, fadrozole [FAD (10 or 50 µg/L)]. The results suggest that BPA did not affect cyp19a1a expression significantly at both concentrations, whereas 50 µg/L of FAD significantly upregulated its expression in ovary. In contrast, BPA exposures increased expression of cyp19a1b in brain of both males and females, whilst FAD had contrasting effects in brain: It increased in males but decreased in females. Similar contrasting responses of cyp19a1b were induced by BPA in gonads: upregulation in ovary and downregulation in testis. FAD did not have a significant effect on gonadal expression of cyp19a1b. Collectively, the results suggest that BPA and FAD can disrupt cyp19a1b activity more readily than can cyp19a1a, albeit with contrasting effects in either a tissue- or sex-specific context that is conceivably consistent with their (BPA and FAD) opposing modes of action. Enhanced spatial and temporal sensitivity of cyp19a1b compared with cyp19a1a suggests that brain sex of fish is more susceptible to disruption by environmental pollutants such as BPA and FAD. Therefore, we propose that the response of cyp19a1b in brain tissue of M. fluviatilis is a more suitable indicator of oestrogenic pollution in the aquatic environment.

Exposure to estrogenic chemicals induces ectopic expression of vtg in the testis of rainbowfish, Melanotaenia fluviatilis.

Vitellogenin (Vtg) is the major egg-yolk precursor protein in oviparous organisms normally synthesised only in mature females. In males and juveniles, the vtg gene, although present, is silent, but its hepatic expression may be activated by xenoestrogens. Surprisingly, its induction and potential consequences in non-hepatic tissues remain unexplored. Here we test the hepatic and testicular response of vtg expression in adult male rainbowfish Melanotaenia fluviatilis exposed to either 1, 3, 5 µg/L 17ß-estradiol or 100, 500 µg/L 4-n-nonylphenol for 24-96 h. Significant increase in the expression level of vtg mRNA in the liver and testes of exposed males was observed. The early (24 h), sensitive and reliable detection of the vtg induction using qPCR demonstrates the assay's robustness to monitor xenobiotic exposure particularly in smaller fish like rainbowfish, an emerging indicator species. Whilst, the ectopic induction of vtg mRNA in testes suggests a more complex Vtg pathway.

Factor structure and normative data of the Sinhalese version of self reported Strength and Difficulties Questionnaire (SDQ) for adolescents.

OBJECTIVES: To describe the normative data, factor structure and the internal consistency of the Sinhalese, self reported version of SDQ for adolescents. METHODS: The present study was carried out in eight provinces in Sri Lanka. A sample of school going adolescents aged 12-16 years were selected from Sinhalese medium schools using a multi stage cluster sampling technique with probability proportionate to size. The component structure of the SDQ was examined using principal component analysis. Normative banding and the cut off values were determined, based on the distribution of raw data in this non-clinical sample. RESULTS: The study sample consisted of 535 (45.3%) boys and 645 (54.5%) girls. Mean total difficulty score for girls (10.66±5.440) was significantly (p=0.014) higher than that for boys (9.93±4.671). Mean scores for emotional (2.97±2.009), conduct (2.11±1.755) and peer (2.24±1.760) subscales were also significantly higher among girls than that of boys (2.7±1.915, 1.78±1.406 and 2.04±1.383 respectively). In the factor analysis, only factor that was loaded with all five items in the original subscale was "emotional" and the loading values were more than .445 for all five items. None of the other extracted factors contained more than 3 items from one subscale. Internal consistency (Cronbach's alpha) for total difficulties was satisfactory in the total sample as well as in boys and girls separately (>.71). However, in all five subscales, Chrobach's alpha was less than six, showing a low homogeneity. CONCLUSIONS: Factor structure and internal consistency of the current Sinhalese version of the self reported SDQ is not satisfactory. Revalidation of this version of SDQ is recommended to capture the intended objectives of the SDQ.

Effects of exposure to oestrogenic compounds on aromatase gene expression are gender dependent in the rainbowfish, Melanotaenia fluviatilis.

This study investigated the influence of two endocrine disrupting chemicals (EDCs)-an exogenous oestrogen 17ß-estradiol (E2) and the oestrogen mimic 4-n-nonylphenol (NP) on the expression of aromatase transcripts in both sexes of adult Murray river rainbowfish. Reproductively active mature fish were exposed to 1, 3, and 5 µg/L E2 or 100 and 500µg/L NP for 24, 48, 72 and 96 h. The results show a significant reduction in the expression of cyp19a1a isoform in ovarian tissues with complete inhibition at the higher concentrations (3 and 5 µg/L E2; 500µg/L NP between 24 and 72 h) and at all concentrations after 96 h. There was no expression of the cyp19a1a isoform in female brain, male brain or testes in any treatment. E2 significantly increased expression of cyp19a1b in female brain except at 5 µg/L after 24h exposure. In male brain tissue E2 exposure decreased cyp19a1b expression except at 1 and 5 µg/L at 24h. NP significantly upregulated cyp19a1b in the female brain (except with 500 µg/L at 72 h) and in testes tissues. NP downregulated expression of cyp19a1b in the male brain tissue. Collectively, these observations support the hypothesis that the expression of cyp19a1b is regulated via both positive and negative feedback mechanisms, with differential modulation based on the type and concentration of the exposed oestrogens, duration of exposure, fish tissue and gender of the fish. The results also imply that exogenous oestrogens can have a disruptive effect on the steroidogenic pathway and may lead to effects on sex differentiation, sexual behaviour and reproductive cycles in this fish.

Effect of different milling methods on glycaemic response of foods made with finger millet (Eucenea coracana) flour.

OBJECTIVES: Compare glycaemic response of foods prepared with finger millet flour, using traditional stone grinding and industrial milling. DESIGN: Crossover study. PARTICIPANTS: Healthy volunteers (n=11) consisting of five males and six females), aged between 20 and 30 years, with a body mass index of 18.5-23.5 Kgm-2. MAIN OUTCOME MEASURES: Blood glucose concentration was measured at fasting and 30, 45, 60, 90, 120 minutes after ingestion of roti and pittu made with stone ground or industrially milled finger millet flour, containing 50 g of available carbohydrates. Glycaemic Index (GI) values were expressed as the average value of the 11 subjects. RESULTS: Significant differences (p<0.05) in GI between similar food types made of flour milled using different methods were observed. GI for roti made of stone ground flour was 44±5 and that of roti made of industrially milled flour was 59±7. Pittu made of stone ground flour had a GI of 67±5 and GI of pittu made of industrially milled flour was 79±5. Microscopic analysis of flour samples and a sieving process using different sieve sizes showed larger particle size distribution in stone ground flour compared to industrially milled flour. CONCLUSIONS: Larger particle sizes in the stone ground flour compared with industrially milled flour was established as the only factor affecting the difference in GI of same type of food prepared with flour milled using different methods. There were no significant differences (p>0.05) in proximate compositions of the different foods or raw flours. Foods prepared with finger millet (kurakkan) flour with a larger particle size distribution resulted in a lower glycaemic response.

Ontogenic and sexually dimorphic expression of cyp19 isoforms in the rainbowfish, Melanotaenia fluviatilis (Castelnau 1878).

To investigate the role of cytochrome P450 aromatase, we isolated cyp19 isoforms in the Murray River rainbowfish, M. fluviatilis. The cloned cDNA for cyp19a1a and cyp19a1b had an open reading frame (ORF) of 492 and 499 amino acid residues, with shared identity of up to 83% and 87% with the corresponding homologues of other teleosts respectively. In contrast, the cyp19a1a and cyp19a1b of the Murray River rainbowfish had a shared identity of only 61%. Not surprisingly, the phylogenetic analysis clustered the M. fluviatilis cyp19 isoforms with the corresponding isoforms of other teleosts, suggesting a shared evolutionary ancestry of the respective isoforms. We also studied the expression of cyp19 isoforms during ontogeny and in adult fish using quantitative Real-Time PCR (qPCR). Results suggest that uniquely only cyp19a1b transcripts are maternally inherited, suggesting its role in early development and growth in the species. In contrast to reports in many teleosts, the cyp19a1a was exclusively expressed in the ovarian tissue and completely absent in other tissues examined, including testis. The cyp19a1b like in most teleosts was predominantly expressed in the brain of both males and females with low level of expression in other tissues including gonads of both sexes.

The association of iron status with educational performance and intelligence among adolescents.

INTRODUCTION: The aim was to identify the association of iron status with educational performance and intelligence of adolescents. METHOD: This was a cross sectional comparative study among adolescents aged 13-15 years. Each iron deficient student was matched with an iron sufficient student from the same school, class and sex. Iron status was based on haemoglobin and serum ferritin levels. The marks for mathematics, science, Sinhala language and social science were considered to assess educational performance. Intelligence was measured by Raven's Standard progressive matrices. All the possible confounders and effect modifiers were considered. Home visits to a sub-sample checked the quality of data. RESULTS: The final analysis included 188 students (94 matched pairs). Neither educational performance nor intelligence showed significant associations with the iron status. The severity of the iron deficiency did not relate to these cognitive variables either. Twenty-three and 8 co-variables showed statistically significant associations with educational performance and intelligence respectively. Following a multiple regression analysis intelligence, the enthusiasm of the student towards learning, occupational ambition, household possession, problems at home and private tuition for mathematics were key factors predicting educational performance. Stunting and educational level of the mother were important factors influencing intelligence. CONCLUSION: Iron status does not play a major role in educational performance and intelligence of school going adolescents. Several factors affect educational performance and intelligence. This study highlights the difficulty in extrapolating the findings of similar studies to different ecological settings.

Assessing the performance of a bdelloid rotifer Philodina acuticornis odiosa acute toxicity assay.

A bioassay using the bdelloid rotifer, Philodina acuticornis odiosa, was evaluated for use as a standard test method for direct toxicity assessment testing in the Australasian region. Philodina acuticornis odiosa was found to be relatively tolerant to phenol (24 h LC50, 142 mg/L). The mortality endpoint was both reliable and repeatable (the coefficients of variation for mortality at the 24 h LC50 concentration ranged from 11%-24% (n = 8)), sufficiently low to warrant further testing with a range of reference toxicants, so that this organism can be included for use as a regulatory test in Australasia.

Alterations of metabolic enzymes in Australian bass, Macquaria novemaculeata, after exposure to petroleum hydrocarbons.

Australian bass Macquaria novemaculeata were exposed to the water-accommodated fraction of Bass Strait crude oil, dispersed crude oil, or burnt crude oil to assess sublethal effects of oil spill remediation techniques on fish. Fish were exposed to these treatments for 16 days either through the water column or by way of a pre-exposed diet of amphipod Allorchestes compressa. Fish gills, liver, and white muscle were sampled and cytochrome C oxidase (CCO) and lactate dehydrogenase (LDH) activities quantified. In all treatments containing fish exposed by way of the water column, aerobic activity increased in the gills, whereas a decrease of this enzymic activity was observed in the liver and white muscle. Exposures by way of the food pathway indicated similar trends. Anaerobic (LDH) activity increased in the gills, liver, and white muscle after waterborne exposures. Stimulation in anaerobic activity also occurred in the liver and white muscle of fish after exposure to contaminated food. CCO activity in the gills was the most sensitive biomarker when monitoring waterborne exposures to petroleum hydrocarbons. In the gills, the dispersed oil treatment resulted in the most pronounced biological response, suggesting that in the short term the use of dispersants on an oil slick might cause the most perturbations to fish metabolism.

The effect of different oil spill remediation techniques on petroleum hydrocarbon elimination in Australian bass (Macquaria novemaculeata).

Petroleum hydrocarbons were investigated in juvenile Australian bass, Macquaria novemaculeata, following exposure to the water accommodated fraction (WAF) of Bass Strait crude oil, chemically dispersed crude oil, and burnt crude oil. Each treatment was administered for 16 days either through the water column or through the diet (amphipod, Allorchestes compressa). Polycyclic aromatic hydrocarbon (PAH) elimination was determined by measuring biliary benzo(a)pyrene (B(a)P) and naphthalene-type metabolites. Biliary PAH-type metabolite concentrations varied with the type of oil spill remediation technique, route of exposure (food versus water), and exposure concentration. Fish exposed to chemically dispersed crude oil via the water exhibited the highest PAH-type biliary metabolite concentrations, relative to fish exposed to other treatments. In fish exposed via the diet, the highest concentration of both types of biliary metabolites also appeared in the dispersed oil-exposed individuals. The results suggest that chemically dispersing oil may have the greatest effect on bioavailability of hydrocarbons, both through waterborne and food chain exposures.

Metabolic responses of fish following exposure to two different oil spill remediation techniques.

To assess the impacts of two oil spill remediation techniques on fish metabolism, change in aerobic and anaerobic enzyme activities in juvenile Australian Bass, Macquaria novemaculeata, was examined. Changes in cytochrome C oxidase (CCO) and lactate dehydrogenase (LDH) activities were investigated following exposure to the crude oil water accommodated fraction (WAF) and chemically dispersed crude oil WAF. There was a significant stimulation in CCO activity in the gills and livers of fish exposed to the WAF of Bass Strait crude oil and chemically dispersed crude oil, compared to the control treatment. In addition, LDH activity was significantly stimulated in the liver of fish exposed to dispersed crude oil WAF, compared to the crude oil WAF. Fish exposed to the dispersed crude oil WAF treatment had significantly higher oxygen consumption, as measured by oxygen depletion in a sealed chamber, than fish exposed to the crude oil WAF and control treatments.

Toxicity of three oil spill remediation techniques to the Australian bass Macquaria novemaculeata.

Australian bass, Macquaria novemaculeata, were exposed to the water accommodated fraction (WAF) of Bass Strait crude oil, dispersed crude oil, burnt crude oil, and 4-chlorophenol. The WAF of dispersed crude oil was the most toxic treatment with 96-h LC(50) values of 7. 15% (7.94% upper and 6.42% lower 95% CI) and 7.45% (8.26% upper and 6.71% lower 95% CI). The WAF of crude oil was less toxic, with 96-h LC(50) values of 43.72% (49.21% upper and 38.87% lower 95% CI) and 45.87% (51.51% upper and 40.97% lower 95% CI). The WAF of burnt crude oil was the least toxic treatment with 96-h LC(50) values of 49.81% (63.33% upper and 39.44% lower 95% CI) and 47.28% (59.72% upper and 37.62% lower 95% CI). Sublethal toxicity of the crude oil WAF and burnt crude oil WAF was observed at dilutions seven to eight times less than in the dispersed crude oil WAF.

Health and social status of an elderly urban population in Sri Lanka.

Although Sri Lanka has generally a young demographic profile, with decreasing overall mortality and birth rates, its population is aging gradually and will continue to do so in the future. In order to have an idea of the needs of the elderly a survey was conducted in a sample of randomly selected Sinhalese elders living in an urban community. Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL) assessments were done. Ten percent of the respondents had at least one ADL impairment. Another ten percent had only IADL impairment. The commonest ADL to be affected were bathing and feeding. Children and the family provide all care for the impaired elderly. The family support system should be encouraged and assisted to prevent the necessity for more formal and expensive institutional care. A large proportion of the elderly were handicapped with defects in vision and hearing and the absence of teeth. Correction of these defects would improve both quality of life of these subjects and reduce their risk of accidents.