Enhanced arsenic removal from aqueous medium by arsenic tolerant groundwater fungi

Aim: Arsenic concentration in groundwater above the acceptable level is of global concern due to its serious human health effects. Application of certain fungi, due to their amazing skill to remove arsenic from arsenic contaminated water has received attention in recent years. The main aim of this study was to isolate arsenic tolerant fungi from arsenic-contaminated groundwater and assess their ability for arsenic removal from the aquatic system in-vitro.Methodology: Fungi were isolated from arsenic-contaminated groundwater (44.9–161.1 mg l-1). An experiment on bioremediation/ removal of arsenic by selected highly arsenic tolerant fungi was conducted by culturing them in arsenic supplemented medium and measuring the arsenic contents in initial and after incubation with fungi using Hydride Generation Atomic Absorption Spectroscopy (HG-AAS) to find out the arsenic removal percentage. Results: In all, ten out of forty-five fungi obtained from highly arsenic-contaminated groundwater (44.9–161.1 mg l-1) were able to remove high arsenic contents (>80%) from liquid medium with >85% arsenite (by 6 fungal isolates) and >85% of arsenate (by 9 fungal isolates). In arsenic tolerance assay, all 10 test fungi grew readily in liquid medium enriched with either arsenate (10 and 20 g l-1) or arsenite (2 g l-1) under laboratory conditions (27±2°C). These fungi showed log phase between 5 to 10 days with stationary phase of 11-15 days. High arsenite concentration (4 g l-1) however, completely inhibited the growth of 50% of these fungal isolates. Five of these isolates showed high tolerance index pattern (0.97- 0.91) as compared to others (0.22–0.13). These fungi greatly altered the pH of arsenic supplemented liquid medium (10 mg l-1) as compared to the control when they were individually cultured. These arsenic tolerant fungal isolates may effectively be used for the bioremediation of arsenic from groundwater. Interpretation: The study suggested that 10 fungal isolates were able to tolerate high arsenic concentrations (20 g l-1 of arsenate and 2 g l-1 of arsenite) and were able to enhance arsenic removal (more than 80%) in liquid medium at neutral pH (7.0) and 27°C temperature.

Single dose intravenous regional antibiotic in clean orthopaedic procedures.

Patients undergoing clean orthopaedic operations with tourniquet in Orthopaedic Department of a tertiary level hospital in Dhaka during August 1999 to March 2002 were consecutively enrolled in a prospective clinical study to explore the efficacy and safety of regional prophylaxis with single dose antibiotic. Eighty two patients with 83 operations received 750-mg cefuroxime in 40 & 20 ml of distilled water, into a dorsal vein of the foot or hand respectively to be operated on immediately after the tourniquet was inflated. Patients with bilateral operation, regional administration of cefuroxime were also repeated for the operation on the other extremity. Follow up ranged from 3 weeks to 2 years & 7 months. None of the patients experienced local or systemic adverse effects following regional administration of cefuroxime. Also none developed early infection (superficial or deep) during the follow-up period. Infective complications at distant sites like UTI were observed in one case with bilateral corrective osteotomy for knocked knee deformity. It was probably due to catheterization in the immediate post-operative period, which was rapidly cured following antibiotic treatment and removal of catheter. Regional administration of single dose antibiotic appears to be a safe and effective prophylaxis for the control of early infection in clean orthopaedic procedures. Late infection is blood borne and that can not be controlled by prophylactic use of antibiotic.

Lateral femoral cutaneous nerve block for split skin grafting.

Wound with loss of skin needs grafting for early healing and to prevent deformity and disability. For skin grafting lateral femoral cutaneous nerve block can be used as regional anesthesia. The efficacy of 55 lateral femoral cutaneous nerve block was assessed in 52 patients of 10 to 70 years of age. The nerve block was found effective in all cases. 90.91% showed excellent results. The procedure seemed to be easy, safe and less costly for the purpose of skin grafting.