VULNERABILITY OF LOW-ARSENIC AQUIFERS TO MUNICIPAL PUMPING IN BANGLADESH.

Sandy aquifers deposited >12,000 years ago, some as shallow as 30 m, have provided a reliable supply of low-arsenic (As) drinking water in rural Bangladesh. This study concerns the potential risk of contaminating these aquifers in areas surrounding the city of Dhaka where hydraulic heads in aquifers >150 m deep have dropped by 70 m in a few decades due to municipal pumping. Water levels measured continuously from 2012 to 2014 in 12 deep (>150m), 3 intermediate (90-150 m) and 6 shallow (<90 m) community wells, 1 shallow private well, and 1 river piezometer show that the resulting drawdown cone extends 15-35 km east of Dhaka. Water levels in 4 low-As community wells within the 62-147 m depth range closest to Dhaka were inaccessible by suction for up to a third of the year. Lateral hydraulic gradients in the deep aquifer system ranged from 1.7×10-4 to 3.7×10-4 indicating flow towards Dhaka throughout 2012-2014. Vertical recharge on the edge of the drawdown cone was estimated at 0.21±0.06 m/yr. The data suggest that continued municipal pumping in Dhaka could eventually contaminate some relatively shallow community wells.

Detecting well casing leaks in Bangladesh using a salt spiking method.

We apply fluid-replacement logging in arsenic-contaminated regions of Bangladesh using a low-cost, down-well fluid conductivity logging tool to detect leaks in the cased section of wells. The fluid-conductivity tool is designed for the developing world: it is lightweight and easily transportable, operable by one person, and can be built for minimal cost. The fluid-replacement test identifies leaking casing by comparison of fluid conductivity logs collected before and after spiking the wellbore with a sodium chloride tracer. Here, we present results of fluid-replacement logging tests from both leaking and non-leaking casing from wells in Araihazar and Munshiganj, Bangladesh, and demonstrate that the low-cost tool produces measurements comparable to those obtained with a standard geophysical logging tool. Finally, we suggest well testing procedures and approaches for preventing casing leaks in Bangladesh and other developing countries.

Post-operative telephone review is cost-effective and acceptable to patients.

INTRODUCTION: Patients undergoing selective minor emergency and elective procedures are followed up by a nurse-led structured telephone review six weeks post-operatively in our hospital. Our study objectives were to review patients' satisfaction, assess cost-effectiveness and compare our practice with other surgical units in Northern Ireland (NI). PATIENTS AND METHODS: Completed telephone follow-up forms were reviewed retrospectively for a three-year period and cost savings calculated. Fifty patients were contacted prospectively by telephone using a questionnaire to assess satisfaction of this follow-up. A postal questionnaire was sent to 68 general and vascular surgeons in NI, assessing individual preferences for patient follow-up. RESULTS: A total of 1378 patients received a telephone review from September 2005 to September 2008. One thousand one hundred and seventy-seven (85.4%) were successfully contacted, while 201 (14.6%) did not respond despite multiple attempts. One hundred and forty-seven respondents (10.7%) required further outpatient follow-up, thereby saving 1231 outpatient reviews, equivalent to £41,509 per annum. Thirty-nine (78%) patients expected post-operative follow-up, with 29 (58%) expecting this in the outpatient department. However, all patients were satisfied with the nurse-led telephone review. Fifty-three (78%) consultants responded. Those who always, or occasionally, review patients post-operatively varies according to the operation performed, ranging from 2.2% appendicectomy patients to 40.0% for varicose vein surgery. CONCLUSION: Current practice in NI varies, but a significant proportion of patients are not routinely reviewed. This study confirmed that patients expect post-operative follow-up. A nurse-led telephone review service is acceptable to patients, cost-effective and reduces the number of unnecessary outpatient reviews.

Cross-species amplification of microsatellite loci within the dioecious, polyploid genus Actinidia (Actinidiaceae).

Microsatellite marker transfer across species in the dioecious genus Actinidia (kiwifruit) could offer an efficient and time-effective technique for use during trait transfer for vine and fruit improvement in breeding programmes. We evaluated the cross-species amplification of 20 EST-derived microsatellite markers that were fully informative in an Actinidia chinensis mapping family. We tested all 20 markers on 120 genotypes belonging to 21 species, 5 with varieties and/or chromosome races. These 26 taxa included 16 diploids, 7 tetraploids, 2 hexaploids and 1 octaploid, and represented all four taxonomic sections in the genus. All 20 markers showed some level of cross-species amplification. The most successful marker amplified in all genotypes from all species from all sections of the genus, the least successful amplified fragments only in A. chinensis and A. deliciosa. One species, A. glaucophylla, failed to amplify with all but 2 markers. PIC (Polymorphism information content) values were high, with 14 of 17 markers recording values of 0.90 and above. Sequence data demonstrated the presence of the microsatellite in all the amplified products. Sequence homology was less 5' of the microsatellite and increased toward the start codon of the translated region of the EST from which the marker was derived. The data confirm that EST-derived microsatellite markers from Actinidia species show cross-species amplification with high levels of polymorphism which could make them useful markers in breeding programmes.

EST-derived microsatellites from Actinidia species and their potential for mapping.

To increase the speed and reduce the cost of constructing a genetic map of Actinidia species (kiwifruit), for use in both breeding and functional genomics programmes, we sampled microsatellites from expressed sequence tags (ESTs) to evaluate their frequency of occurrence and level of polymorphism. Perfect dinucleotide repeats were the microsatellites selected, and these were found to be numerous in both the 5' and 3' ends of the genes represented. The microsatellites were of various lengths, the majority being repeats with the pattern (CT)(n)/(GA)(n). One hundred and fifty microsatellites, each with more than 10 dinucleotide repeat units, were chosen as possible markers, and when these were amplified, 93.5% were found to be polymorphic and segregating in a mapping population, with 22.6% amplifying more than one locus. Four marker categories were identified. Fully informative markers made up 27% of the total, 36.2% were female informative, 25.8% were male informative and 10% partly informative. The mapping population was an intraspecific cross in the diploid species Actinidia chinensis, with parents chosen for their diversity in fruit and plant characteristics, and for their geographical separation. Linkage was tested using the software 'Joinmap' and a LOD value of 3. The distribution of the EST-based markers over the linkage groups obtained appeared to be random, taking into consideration the small sample size, that the number of linkage groups (31) exceeded the chromosome number of n=29, and that a number of markers were not assigned to any group. Some microsatellite markers which amplified more than one locus mapped to separate linkage groups. According to our study in A. chinensis, EST-derived microsatellites give large numbers of possible markers very quickly and at reasonable cost. The markers are highly polymorphic, segregate in the mapping population, and increase the value of the genomic map by providing some functional information.

The need for closer control of warfarin therapy.

Warfarin therapy is associated with a variety of haemorrhagic complications. We report a representative series of six cases of warfarin-induced bleeding in non-cerebral sites admitted to one unit. In all of these cases, there was inadequate control of anticoagulation, resulting in major morbidity and one death. In particular, closer attention must be paid to the indications for and duration of warfarin treatment.

Experience in low velocity gunshot injuries: a more conservative approach in selected cases.

Sixty-eight patients with gunshot and blast injuries who had sustained 200 wounds were treated in a single surgical unit over an 18-month period. Many of these were low velocity injuries to the soft tissues of the lower limbs. A change of policy was adopted for this selected group which involved minimum wound debridement under local anaesthesia in association with antibiotics. This policy enables early discharge from hospital and has resulted in a low infection rate with no significant morbidity.

Activity and transport of antithrombin during acute limb ischemia.

Antithrombin (AT III), a major circulating anticoagulant, may be influenced by ischemia-induced changes in microvascular integrity and contribute to localized hypercoagulability. In a nonheparinized intact canine hindlimb model we determined AT III activity by chromogenic substrate assay (S-2238); coagulation changes with fibrinogen, activated partial thromboplastin time (aPTT), and prothrombin time (PT); and transvascular exchange by lymph-to-plasma total protein concentration ratio. Femoral venous plasma and lymph samples were assayed during 1 hour of steady state (C), 6 or 8 hours of aortoiliac occlusion (I), and 1 or 3 hours of reperfusion (R). Four groups were studied: GI, sham operated (n = 5); GII, moderate ischemia (n = 7), arterial pressure 30% to 45% C, GIII, 6 hours of severe ischemia (n = 7), arterial pressure 5% to 20% C; and GIV, 8 hours of severe ischemia (n = 5), arterial pressure 5% to 20% C. All parameters varied near baseline in the control group and the group with moderate ischemia. Fibrinogen decreased after 3 hours of ischemia in GIII from 218 +/- 38 to 175 +/- 46 mg/dl (mean +/- SEM) and in GIV from 254 +/- 39 to 201 +/- 44 mg/dl (p less than 0.005) as aPTT and PT increased. All parameters returned to baseline on R in GIII only. Plasma AT III decreased in GIV from 89% +/- 4.6% to 53.6% +/- 16.2% (p less than 0.005) after 3 hours and remained low during late I and R.(ABSTRACT TRUNCATED AT 250 WORDS)

Activity of primate magnocellular red nucleus related to hand and finger movements.

Single cells were recorded in the magnocellular red nucleus (RNm) of two cynomolgus monkeys using tungsten microelectrodes. The first monkey was trained to press finger switches and to operate a push-pull device. Comparison of responses while operating the two devices demonstrated a strong distal bias. The finger device elicited large modulations in discharge (greater than or equal to 50 impulses/s) in 75% of the sampled neurons. Most cells fired optimally during thumb switch operation, but also fired vigorously in association with other switch operations. The left motor cortex was removed from the second monkey 18 months prior to microelectrode recording. Cells in the cortically denervated RNm discharged vigorously in association with grouped finger movements that opened and closed the affected right hand. These results coupled with our previous findings suggest that the RNm is preferentially linked to distal limb muscles, and the primary role of the forelimb zone may be to control coordinated hand function including grouped movements of the fingers.

An attempt to improve auditory short-term memory in Down's syndrome individuals through reducing distractions.

Down's syndrome (DS) individuals, relative to nonretarded individuals, have greater difficulty remembering brief sequences of verbal information presented auditorily. Previous research suggests at least two possible attentional explanations of their difficulty: They are especially susceptible to both auditory distraction and off-task glancing during laboratory tasks. DS, non-DS mentally retarded and nonretarded persons listened to, looked at, and attempted to remember sequences of digits. Although the three groups did not differ in their recall of visually-presented stimuli, DS subjects showed significantly poorer recall of auditorially-presented stimuli than the other two groups (which did not differ). Furthermore, the poor auditory memory of DS subjects did not improve under testing conditions designed to minimize auditory and visual distractions. It was suggested that poor auditory short-term memory for verbal information is tied more closely to Down's syndrome than to low intelligence and does not seem to be caused by a special susceptibility of Down's syndrome individuals to attentional distractors.

Transvascular protein movement in the intact ischemic hindlimb.

Postischemic limb swelling following reperfusion may be related to microvascular changes associated with ischemia. We used lymph-to-plasma total protein concentration ratios (L/P) and lymph flow (QL) as an index of transvascular exchange in the intact dog hindlimb during steady state (C) (1 hr), ischemia (I) (6 hr), and reperfusion (R) (3 hr). Central pressures, femoral arterial and venous pressures (PA, PV) and QL were recorded every 15 min. Lymph was collected from a femoral lymphatic in the passively flexed leg (50 cycles/min). Three groups of animals were studied: GI, sham-operated (N = 5); GII, moderate ischemia (N = 7, PA = 30-45% C); and GIII, severe ischemia (N = 7, PA = 5-20% C). In GI, QL gradually increased over 10 hr without change in L/P. Moderate ischemia produced a decrease in QL, 3.55 +/- 2.02 mg/hr to 0.92 +/- 0.53 mg/hr (P less than 0.0001), and QL remained below baseline during R with no change in L/P over the 10 hr. Severe ischemia produced a similar decrease in QL, 1.91 +/- 2.05 mg/hr to 0.15 +/- 0.1 mg/hr (P less than 0.01); however, an increase to 2.56 +/- 2.14 mg/hr occurred during R. Severe ischemia increased L/P 0.42 +/- 0.08 to 0.64 +/- 0.23 (P less than 0.001) and remained elevated during R at 0.63 +/- 0.18 (P less than 0.001). An increase in the wet-to-dry weight ratio of ischemic to nonischemic muscle after reperfusion was noted only in GIII, 3.82 +/- 1.17 vs 2.60 +/- 0.45 (P less than 0.04). Severe ischemia produces changes in vascular integrity which augment protein flow. Prevention of these vascular changes may help to minimize the muscle swelling of reperfusion.

Experimental comparison of percutaneous vena caval devices: titanium Greenfield filter versus bird's nest filter.

A venous embolism model with autogenous thrombus was used for comparison of the functional properties of two new vena caval devices: a titanium Greenfield filter and the bird's nest filter. All nine Greenfield filters were correctly placed in the inferior vena cava and produced significant clot lysis of 81.3% +/- 16.3% (p less than 0.001, paired t test). Difficulty was encountered in affixing the hooks of the bird's nest device into the vein wall and resulted in two filters not being inserted and two filters being placed too proximally. One set of hooked wires of another bird's nest device migrated to the right atrium despite correct insertion. Eight bird's nest devices allowed clot lysis of 83.4% +/- 17.7% (p less than 0.001), paired t test) but thrombus size was increased in one case. The Greenfield and bird's nest filters have comparable effects on trapped emboli, but the bird's nest filter may be susceptible to thrombosis and occlusion under certain circumstances. The pre-shaped hooked wires of the bird's nest device may be difficult to insert and may allow proximal migration after a large thrombus was trapped.

Ibuprofen and methylprednisolone in a pig Pseudomonas ARDS model.

The effects of ibuprofen (I) and methylprednisolone (M) were studied in the Pseudomonas porcine model of adult respiratory distress syndrome (ARDS). Four groups of animals were anesthetized and ventilated with 0.5 FIO2, 5 cm PEEP, and 20 cc/kg tidal volume: a control group given saline alone; Pseudomonas infusion alone (P); Pseudomonas with ibuprofen (I), 12.5 mg/kg given at 20 and 120 min; and P with methylprednisolone (M), 30 mg/kg given at 20 and 120 min. We compared the alteration in pulmonary hemodynamics with the alteration in the plasma concentration of thromboxane (TxB2) and 6-keto PGF1 alpha in the treated and untreated groups. Hemodynamic parameters measured included the pulmonary (PAP) and systemic (SAP) arterial pressures, cardiac index (C1), thermal-cardiogreen extravascular lung water (EVLW), and PaO2. Albumin Flux was measured by a gamma scintigraphic method (slope index; SI). P produced a dramatic increase in PAP (P less than 0.05) with a progressive increase in EVLW and SI (P less than 0.05) and fall (P less than 0.05) in PaO2, CI, and SAP. The acute pulmonary hypertension was associated with a significant rise in TxB2 and 6-keto PGF1 alpha in the Pseudomonas group. I effectively blocked the elevation of TxB2 and caused a significant but transient improvement in PAP and rise in PaO2. Albumin flux and water leak as measured by SI and EVLW were not affected by ibuprofen. M reduced the elevation of TxB2 and 6-keto PGF1 alpha but failed to block these prostaglandins significantly.(ABSTRACT TRUNCATED AT 250 WORDS)