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Aim: Potential microbial isolates for bioremoval of copper were collected from phenolic and heavy metal-contaminated soils and screened in copper-containing medium for determining the maximum tolerance level for copper. Methodology: Bioremoval of copper was assessed using sodium diethyl dithiocarbamate assay. Physical and cultural conditions influencing copper bioremoval such as initial concentration, biomass dosage (inoculum volume), temperature and pH were optimised via one-factor-at-a-time. Results: The highest maximum tolerance level was displayed by Serratia sp. AQ5-03 at 600 mg l-1, while for Alcaligenes sp. AQ5-02 and Pseudomonas sp. AQ5-04 it was 500 mg l-1. The highest bioremoval for Alcaligenes sp. AQ5-02, Serratia sp. AQ5-03 and Pseudomonas sp. AQ5-04 was achieved at 20, 50 and 75 mg l-1, respectively. The optimum biomass dosage (inoculum volume) for both Serratia sp. AQ5-03 and Pseudomonas sp. AQ5-04 were 15%, whereas it was 10% for Alcaligenes sp. AQ5-02. The results also revealed that maximum bioremoval was achieved at pH 6 at an optimum temperature of 20°C for both Alcaligenes sp. AQ5-02 and Pseudomonas sp. AQ5-04, while Serratia sp. AQ5-03 showed optimum removal at pH 7 and at 30°C temperature. The maximum bioremoval efficiency for Alcaligenes sp. AQ5-02, Serratia sp. AQ5-03 and Pseudomonas sp were found to be 62, 57 and 70%, respectively. Interpretation: The results indicate that Alcaligenes sp. AQ5-02, Serratia sp. AQ5-03, Pseudomonas sp. AQ5-04 can be utilised as bioremoval agent since it possessed the highest bioremoval efficiency for copper remediation.
ABSTRACT
Aim: The cholinesterase (ChE) based inhibition and histopathological studies from fish were investigated and represented in this study to develop as one of the great potential biomarkers for heavy metals monitoring. Methodology: In this study, the histopathological study of gills were observed a under microscope. The capability of ChE extracted from the gills of Clarias gariepinus was assessed for declining Cd. ChE was purified through affinity chromatography and continued with the optimisation and inhibition study (IC50) of cholinesterase. Results: Histopathological study of gills was carried out and several changes such as aneurysm, necrosis and lamella fusion were noted. Purification fold obtained from purified enzyme was 1.15 with 30% a yield specific activity 20.726. The optimum temperature for purified AChE was 35°C along with acetylthiocholine iodide (ATC) as a preferable substrate that had the highest Vmax value of 0.5452 U mg-1 and the lowest Km value of 0.0311 mM. The optimum pH was observed to be 10 of Tris-HCl as a medium. Meanwhile, the IC50 of cadmium was 6.808 mg l-1 with R2 value of 0.9532. Interpretation: The result of the study can be used as a tool for further developing a biomarker for the detection of heavy metals in aquatic ecosystems. In addition, the baseline data provided can also be used for designing a kit, which would give rapid and accurate result.
ABSTRACT
Aim: Cholinesterase (ChE) inhibition and histopathological features of brain tissues of Clarias gariepinus were investigated with a purpose to develop biomarkers for monitoring heavy metals. Methodology: The effects of cadmium toxicity on C. gariepinus were assessed by ChE inhibition and characterisation of ChE by affinity chromatography and histological variations in brain tissues were studied by H&E staining under light microscope. Results: The purified enzyme gave 10.58 fold purification with the recovery of 12% with specific activity of 159.729 U mg-1. The Michaelis-Menten constant (Km) and Vmax value obtained was 1.985 mM and 0.4479 µmol min-1 mg-1, respectively. The enzyme showed the ability to hydrolyse acetylthiocholine iodide (ATC) at a faster rate compared to other two synthetic substrates, propionylcholine iodide (PTC) and butyrylthiocholine iodide (BTC). ChE showed highest activity at 35°C in Tris-HCl pH 7.5. The metal inhibition study also found the maximal inhibitory concentration (IC50) value for cadmium to be 0.6517 mg l-1. Histological study revealed decrease in the number of cells, degeneration of Purkinje cells, increased aggregation area and cells necrosis. Interpretation: Inhibition of cholinesterase activity and degeneration of Purkinje cells observed in the present study can be used as a tool for further developing a biomarker for detecting heavy metals in the aquatic ecosystems.
ABSTRACT
Smoking among school children is becoming a serious problem in developing countries, including Bangladesh. The early initiation of smoking needs urgent intervention to protect this vulnerable group and preventing them to be addicted. This study aims to determine the age at initiation of smoking and factors affecting it. A two-stage cluster sampling was used with a selection of schools on probability proportional to enrolment size followed by stratified random sampling of government and private schools and then a random start in classes VIII, IX and X of each school targeting the students aged 13 years and above. Data collected from secondary school students using self-administered structured questionnaire. All analyses were performed with SPSS version 20.0. Missing value was treated by multiple imputations. A total of 6877 data were analysed in which 84.7% were non-smoker, 9.5% were ever smoker and 5.8% were current smokers. Among the ever smoker (n=823), 38% were current smokers, 56.5% former and 5.5% were recent quitters. The mean (SD) age at initiation of smoking was 10.9 (0.2) years. Multinomial regression analysis revealed that class grade, peer pressure and offered free cigarette appeared to be significant predictors of smoking initiation (p0.05). Promotion of smoking resistance skills among children and teens through comprehensive approaches designed to enhance general personal competence by teaching an array of personal and social life skills is recommended.
Subject(s)
Smoking , Schools , Students , Developing CountriesABSTRACT
HCV infection remains a common problem in patients with end stage renal disease [ESRD] undergoing maintenance dialysis especially Haemodialysis [HD]. Inspite that dialysis patients usually are not immunologically competent due to uraemia, hepatitis C virus infection runs usually indolent course. A number of studies support the notion that this dynamics of HCV viral load may be related to lowering of HCV RNA titres during the HD procedure that could be related to the dialyser immaterial used. This work aimed mainly to study the change in HCV RNA titre before and after HD session using low flux dialyser. 18 HCV positive, end stage renal disease [ESRD] patients on regular HD with detectable viral RNA using qualitative polymerase chain reaction [PCR] technique were included. All patients had quantitative PCR just before and at the end of a single 4 hours HD session. Standard low flux [Cuprophan or Polysulphon] dialysis filters 1.2m[2] surface area were used for all patients included. Mean HCV RNA for all patients pre dialysis was 135, 143 +/- 16,993 copies/ml. Mean post dialysis HCV RNA was 78, 786 +/- 48,651 copies/ml. Observed reduction in HCV title post/pre dialysis ratio 13.8%-82.l% with median value of +/- 40%. There was a significant reduction in the level of HCV RNA after dialysis [p<0.001, 95% Confidence Interval 125, 332-144, 954]. Low flux haemodialysis session has a significant effect on hepatitis C viral load with marked reduction in HCV RNA that can have a positive impact on the prognosis of hepatitis C in ESRD on regular HD
Subject(s)
Humans , Male , Female , Hepacivirus , Kidney Failure, Chronic , RNA, Viral , Polymerase Chain Reaction , PrognosisABSTRACT
High risk renal failure patients have increased risk for contrast nephropathy during coronary angiography despite the use of conventional prophylaxis with intravenous hydration and acetylcysteine. The aim of the study was assess the role of haemo filtration versus conventional prophylaxis in preservation of kidney function and prevention of contrast nephropathy in chronic kidney disease patients undergoing cardiac catheterisation. There was a highly significant reduction in BUN, creatinine, serum uric acid [p<0.001] in haemofiltration group in comparison with baseline and control group till day 4 that was not significant after one week. There was a significantly improving rise in pH and serum HCO[3] level in haemofiltration in haemofiltration group till 24 hours post contrast injection [p<0.001]. Haemofiltration can provide adequate pres ervation of kidney function in high risk renal patients under going cardiac catheterisation. It also achieved proper adjustment of acid/base status in such patients