Small-scale density variations in the lunar crust revealed by GRAIL.

Data from the Gravity Recovery and Interior Laboratory (GRAIL) mission have revealed that ~98% of the power of the gravity signal of the Moon at high spherical harmonic degrees correlates with the topography. The remaining 2% of the signal, which cannot be explained by topography, contains information about density variations within the crust. These high-degree Bouguer gravity anomalies are likely caused by small-scale (10's of km) shallow density variations. Here we use gravity inversions to model the small-scale three-dimensional variations in the density of the lunar crust. Inversion results from three non-descript areas yield shallow density variations in the range of 100-200 kg/m3. Three end-member scenarios of variations in porosity, intrusions into the crust, and variations in bulk crustal composition were tested as possible sources of the density variations. We find that the density anomalies can be caused entirely by changes in porosity. Characteristics of density anomalies in the South Pole-Aitken basin also support porosity as a primary source of these variations. Mafic intrusions into the crust could explain many, but not all of the anomalies. Additionally, variations in crustal composition revealed by spectral data could only explain a small fraction of the density anomalies. Nevertheless, all three sources of density variations likely contribute. Collectively, results from this study of GRAIL gravity data, combined with other studies of remote sensing data and lunar samples, show that the lunar crust exhibits variations in density by ±10% over scales ranging from centimeters to 100's of kilometers.

Trends in orthopaedic antimicrobial prophylaxis in the UK between 2005 and 2011.

INTRODUCTION: Antimicrobial prophylaxis remains the most powerful tool used to reduce infection rates in orthopaedics but the choice of antibiotic is complex. The aim of this study was to examine trends in antimicrobial prophylaxis in orthopaedic surgery involving the insertion of metalwork between 2005 and 2011. METHODS: Two questionnaires (one in 2008 and one in 2011) were sent to all National Health Service trusts in the UK using the Freedom of Information Act. RESULTS: In total, 87% of trusts that perform orthopaedic surgery responded. The use of cefuroxime more than halved between 2005 and 2011 from 80% to 36% and 78% to 26% in elective surgery and trauma surgery respectively. Combination therapy with flucloxacillin and gentamicin rose from 1% to 32% in elective and 1% to 34% in trauma surgery. Other increasingly popular regimes include teicoplanin and gentamicin (1% to 10% in elective, 1% to 6% in trauma) and co-amoxiclav (3% to 8% in elective, 4% to 14% in trauma). The majority of changes occurred between 2008 and 2010. Over half (56%) of the trusts stated that Clostridium difficile was the main reason for changing regimes. CONCLUSIONS: In 2008 a systematic review involving 11,343 participants failed to show a difference in surgical site infections when comparing different antimicrobial prophylaxis regimes in orthopaedic surgery. Concerns over C difficile and methicillin resistant Staphylococcus aureus have influenced antimicrobial regimes in both trauma and elective surgery. Teicoplanin would be an appropriate choice for antimicrobial prophylaxis in both trauma and elective units but this is not reflected in its current level of popularity.

Activity levels after pulmonary rehabilitation - what really happens?

OBJECTIVES: To assess the changes in physical activity in subjects with chronic obstructive pulmonary disease over 6months after pulmonary rehabilitation. DESIGN: Prospective, observational study. Activity was measured over 2-day periods at the end of rehabilitation, and repeated every 6weeks for 6months using the ActivPAL uni-axial accelerometer. These results were compared with the shuttle walking test (SWT) and the St. George's Respiratory Disease Questionnaire (SGRDQ). SETTING: UK community hospital. PARTICIPANTS: Adults completing a community rehabilitation programme. MAIN OUTCOME MEASURE: Time spent standing and mobilising ('uptime'). RESULTS: Of 34 subjects recruited, 28 completed the 6-month study period (mean age 69years, mean forced expiratory volume in 1second 1.3l). Participants wore the monitor for 13.8 to 14.2hours/day. At baseline (post-rehabilitation), participants spent 1.7 [standard deviation (SD) 1.3]hours/day walking and 3.5 (SD 2.6)hours/day standing. Taking the group as a whole, mean uptime decreased marginally by 13.6minutes after 24weeks compared with baseline, with significant individual variability. In all but one subject who showed decreased activity, this was apparent after 6weeks. There were no significant changes in the mean SWT or SGRDQ. Significant associations between total uptime and the SWT were found, but coefficients were weak. It was not possible to predict individual responses from baseline data. CONCLUSION: The accelerometer provides useful supplementary data in patients completing rehabilitation programmes, and the results reveal wide variation. The weak associations between activity data and the SWT suggest that monitors provide additional information. More work is required to determine the factors associated with early deterioration in activity in order to design appropriate interventions.

Pediatric fractures: temporal trends and cost implications of treatment under general anesthesia.

PURPOSE: Pediatric fractures are common and are often managed by manipulation under general anesthesia (MUA). This study's aim was to assess the changing pattern of pediatric fractures over 6 years and use this data to perform a workload forecast and estimate cost implications of treatment under general anesthesia. METHODS: The Emergency Department (ED), operating theater and ward admissions data of children aged 1-11 years presenting with fractures was analyzed. We calculated caseload trends, delay to operation, various parameters of service provision, and the current cost of treating each fracture. We then performed predictive cost analysis for the next 3 years to estimate potential savings by manipulating fractures in ED under ketamine sedation. RESULTS: The case load has increased >350% in 6 years (total fractures increasing at 23% and MUAs increasing at 17% per year, respectively). The summer months and evenings have been consistently busier. 72% of fractures were managed by pure reduction alone (MUA), 22% by reduction + K-wires, and various other procedures were performed in 1%. The median delays from ED presentation to admission, definitive procedure and discharge were 4, 21 and 33 h, respectively. Each MUA took 52 min and cost the hospital £723. Assuming that the current trends continue, the expenditures would be £101 K, £114 K, and £128 K for 2010, 2011 and 2012, respectively. DISCUSSION: Fracture manipulation in children under general anesthesia often requires an overnight hospital stay, which is not only uncomfortable for the child and inconvenient for the parents but it also increases the burden on the limited National Health Service (NHS) resources. There is a 23% annual increase in fractures and children have to wait for 21 h before the definitive procedure. Using ketamine to manipulate children's fractures in the ED could offer potential service and cost improvements.

Targeted mapping of Cdu1, a major locus regulating grain cadmium concentration in durum wheat (Triticum turgidum L. var durum).

Some durum wheat (Triticum turgidum L. var durum) cultivars have the genetic propensity to accumulate cadmium (Cd) in the grain. A major gene controlling grain Cd concentration designated as Cdu1 has been reported on 5B, but the genetic factor(s) conferring the low Cd phenotype are currently unknown. The objectives of this study were to saturate the chromosomal region harboring Cdu1 with newly developed PCR-based markers and to investigate the colinearity of this wheat chromosomal region with rice (Oryza sativa L.) and Brachypodium distachyon genomes. Genetic mapping of markers linked to Cdu1 in a population of recombinant inbred substitution lines revealed that the gene(s) associated with variation in Cd concentration resides in wheat bin 5BL9 between fraction breakpoints 0.76 and 0.79. Genetic mapping and quantitative trait locus (QTL) analysis of grain Cd concentration was performed in 155 doubled haploid lines from the cross W9262-260D3 (low Cd) by Kofa (high Cd) revealed two expressed sequence tag markers (ESMs) and one sequence tagged site (STS) marker that co-segregated with Cdu1 and explained >80% of the phenotypic variation in grain Cd concentration. A second, minor QTL for grain Cd concentration was also identified on 5B, 67 cM proximal to Cdu1. The Cdu1 interval spans 286 kbp of rice chromosome 3 and 282 kbp of Brachypodium chromosome 1. The markers and rice and Brachypodium colinearity described here represent tools that will assist in the positional cloning of Cdu1 and can be used to select for low Cd accumulation in durum wheat breeding programs targeting this trait. The isolation of Cdu1 will further our knowledge of Cd accumulation in cereals as well as metal accumulation in general.

"It's crucial they're treated as patients": ethical guidance and empirical evidence regarding treating doctor-patients.

Ethical guidance from the British Medical Association (BMA) about treating doctor-patients is compared and contrasted with evidence from a qualitative study of general practitioners (GPs) who have been patients. Semistructured interviews were conducted with 17 GPs who had experienced a significant illness. Their experiences were discussed and issues about both being and treating doctor-patients were revealed. Interpretative phenomenological analysis was used to evaluate the data. In this article data extracts are used to illustrate and discuss three key points that summarise the BMA ethical guidance, in order to develop a picture of how far experiences map onto guidance. The data illustrate and extend the complexities of the issues outlined by the BMA document. In particular, differences between experienced GPs and those who have recently completed their training are identified. This analysis will be useful for medical professionals both when they themselves are unwell and when they treat doctor-patients. It will also inform recommendations for professionals who educate medical students or trainees.

A randomised prospective comparison of Rotecno versus new Gore occlusive surgical gowns using bacterial air counts in ultraclean air.

Ultraclean air (UCA) in operating theatres is defined as <10 colony-forming units (cfu)/m(3). The current European standards for surgical gowns are contained in EN13795 but these do not include containment of bacterial dispersal as a standard test. A trial in 2003 found that there were bacterial air counts of 1 cfu/m(3) with Rotecno gowns and 0.5 cfu/m(3) with body exhaust suits in total knee arthroplasty (TKA). This study compared bacterial air counts using Rotecno gowns with a new type of occlusive gown made from Gore liquid-proof fabric, which were superior to the Rotecno gowns on standard EN13795 laboratory testing. Fifty-six joint replacements were allocated randomly either to Rotecno or to Gore gowns with stratification into TKA, total hip arthroplasty (THA) or revision THA. Airborne bacteria were collected from within 30 cm of the wound for the first 10 min of surgery using a Casella slit sampler. The new gowns were associated with higher air counts (3.7 cfu/m(3)) than the Rotecno gowns (1.2 cfu/m(3)) (P<0.001). Three of the Gore samples exceeded the clean air standard of 10 cfu/m(3). In TKA patients, the existing Rotecno gowns, now many years old, had higher air counts (2.0 cfu/m(3)) than in the 2003 trial (0.8 cfu/m(3)) (P<0.001). The new gowns were superior in standard laboratory tests but not superior at preventing airborne bacterial dispersal. Rotecno gowns, although many years old, were still effective. This study highlights the importance of testing new materials in a clinical environment with UCA; in-vitro testing alone is probably not an adequate assessment.

Automated surgical screwdriver: automated screw placement.

The use of power screwdrivers and drills for tapping and screw insertion in surgery is becoming more common. It has been established from clinical observations that the use of a small air drill for inserting self-tapping screws provides improved coaxial alignment and precision, and that the drill should be stopped before the screw head is completely seated on the plate, presumably to reduce the risk of over-tightening. The risk of overrun and over-tightening during tapping and screw insertion is increased with the use of power tools. Prevention of over-tightening is dependent upon when the surgeon detects the onset of tightening, both visually and from the feel of the rapid increase in torque. If detection is too late, then over-tightening or stripping can occur. This study is concerned with using a mechatronic screwdriver to control the tapping depth and to prevent the over-tightening of screws. The effects of various parameters upon the torque profile during tapping and screw insertion have been investigated in synthetic bone and sheep tibia. An automated system is proposed for preventing over-tightening of pre-tapped and self-tapping screws when attaching a surgical plate to a sheep tibia in vitro. The system was used to attach a plate to a sheep tibia using self-tapping screws. The mean torque of the screws inserted using the automated system was 35 per cent of the stripping torque.

Brief exposure of 0.05% chlorhexidine does not impair non-osteoarthritic human cartilage metabolism.

Jet lavage with chlorhexidine 0.05% is an effective means of wound decontamination with 99% of bacteria removed or killed after 1min. Reports of chondrolysis following exposure to concentrations of >0.05% or prolonged exposure to chlorhexidine have curtailed its use in orthopaedic practice. Using radiolabelled sulphur uptake to measure cartilage metabolism, we quantitatively assessed the in-vitro effect of osteoarthritic and non-osteoarthritic human cartilage exposure to chlorhexidine 0.05% for 1min and 1h. The metabolism of non-osteoarthritic cartilage was not significantly affected by a 1min exposure to chlorhexidine 0.05% whereas that of osteoarthritic cartilage was markedly impaired. Prolonged exposure for 1h markedly affected both types of cartilage. These results are encouraging in that 0.05% chlorhexidine may have a role in the decontamination of contaminated open joint injuries in patients with no signs of osteoarthritis. Until there is further understanding of the mechanism underlying reported incidents of chondrolysis following its use, however, it cannot be recommended for the irrigation of 'clean' articular cartilage.

Managing osteoporosis in patients with fragility fractures: did the British Orthopaedic Association guidelines have any impact?

INTRODUCTION: The incidence of fragility fractures could double in the next 50 years. Effective treatments for osteoporosis exist and the British Orthopaedic Association (BOA) has guidelines governing how to manage underlying osteoporosis in patients with fragility fractures. This study assessed how well two trauma units treat underlying osteoporosis and whether the BOA guidelines made any impact. PATIENTS AND METHODS: Case notes of patients with a fracture of their proximal femur admitted during January and February in 2003, 2004 and 2005 were reviewed. The results were analysed for differences between site and year. RESULTS: A total of 602 case notes were reviewed. There was a significant difference in the number of patients discharged on osteoporosis medication between the two sites (27% at LRI, 8% at KGH; P < 0.001), but not between 2003 and 2005 (22% and 16%; P = 0.16). Of the patients started on treatment, 83% were started on calcium and/or vitamin D(3) supplements. CONCLUSIONS: The number of patients who had their underlying osteoporosis addressed was low and the type of treatment sub-optimal. This suggests the BOA guidelines have not made an impact and further work is required to improve the management of these patients.

X-ray-based machine vision system for distal locking of intramedullary nails.

In surgical procedures for femoral shaft fracture treatment, current techniques for locking the distal end of intramedullary nails, using two screws, rely heavily on the use of two-dimensional X-ray images to guide three-dimensional bone drilling processes. Therefore, a large number of X-ray images are required, as the surgeon uses his/her skills and experience to locate the distal hole axes on the intramedullary nail. The long-term effects of X-ray radiation and their relation to different types of cancer still remain uncertain. Therefore, there is a need to develop a surgical technique that can limit the use of X-rays during the distal locking procedure. A robotic-assisted orthopaedic surgery system has been developed at Loughborough University to assist orthopaedic surgeons by reducing the irradiation involved in such operations. The system simplifies the current approach as it uses only two near-orthogonal X-ray images to determine the drilling trajectory of the distal locking holes, thereby considerably reducing irradiation to both the surgeon and patient. Furthermore, the system uses robust machine vision features to reduce the surgeon's interaction with the system, thus reducing the overall operating time. Laboratory test results have shown that the proposed system is very robust in the presence of variable noise and contrast in the X-ray images.

Displaced intra-articular calcaneal fractures: 15-year follow-up of a randomised controlled trial of conservative versus operative treatment.

AIM: To report the 15-year follow-up of displaced intra-articular calcaneal fractures from a randomised controlled trial of conservative versus operative treatment published in 1993. PATIENTS AND METHODS: Of the initial study, 46 patients (82%) were still alive at a mean of 15 years post injury and 26 patients (57%) agreed to review. The patients had been randomly allocated to either conservative or operative treatment in the original study. Clinical [American orthopaedic foot and ankle society hindfoot scale (AOFAS), foot function index (FFI) and calcaneal fracture score] and radiological (Böhler's angle and calcaneum height) outcome measures were used. The grade of osteoarthritis was also assessed at long-term follow-up. RESULTS: At long-term follow-up, the clinical outcomes were not different between conservative versus operative treatment. AOFAS hindfoot scale: conservative=78.5 and operative=70, p=0.11; FFI: conservative=24.4 and operative=26.9, p=0.66; calcaneal fracture score: conservative=70.1 and operative=63.5, p=0.41. The radiological outcomes were also not different between both groups. Böhler's angle: conservative=10.4 degrees and operative 16.9 degrees , p=0.07; height of calcaneum: conservative=37.2mm and operative=38.2mm, p=0.57; grade of osteoarthritis of the sub-talar joint: p=0.54. There was no correlation between Böhler's angle and the outcome measures in either group. CONCLUSION: The results of this 15-year follow-up of displaced intra-articular calcaneal fracture randomised controlled trial were equivalent between conservative and operative treatment and demonstrate similar findings to those at one year follow-up.

Applications of nanotechnology in orthopaedics.

Nanotechnology is the application of science and engineering at the nanoscale. A diverse range of applications are beginning to emerge in all areas of medicine. We performed a survey from November 2005 to March 2006 using the Internet search engines PubMed, ScienceDirect, ISI Web of Knowledge, and Google Scholar. We report on the role of nanotechnology in orthopaedics, exploring current and potential applications. Nanostructured materials have been proposed as the next generation of orthopaedic implant properties by creating a surface environment more conducive for osteoblast function. Bone substitute materials, whose nanoscale composition emulates the hierarchic organization of natural bone, shows initiation of the desirable formation of an apatite layer. Nanotechnology also has been harnessed to improve the cutting performance and quality of surgical blades. Postoperative infection rates may be reduced by using nanofibrous membrane wound dressings containing antibacterial properties. The most notable application of nanotechnology in orthopaedics may be drug delivery, including nanotherapeutics for treating bone cancer and arthritis. Nanotechnology is being used in orthopaedics, and likely will play a valuable role in future developments.

What do patients really want to know in an informed consent procedure? A questionnaire-based survey of patients in the Bath area, UK.

BACKGROUND: Medical decision making is based on patient autonomy and informed consent, which is an integral part of medical ethics, risk management and clinical governance. Consent to treatment has been extensively discussed, but the viewpoint of patients is not well represented. A new consent form was introduced by the Department of Health in 2001. AIMS: To determine the information most important to patients, to facilitate evidence-based guidelines and to provide a valid and reliable consent-procedure-satisfaction questionnaire. METHODS: An anonymous quantitative survey was carried out, asking 100 patients 15 questions regarding procedures they may need to undergo, using a Visual Analogue Scale to test the importance of each question. RESULTS AND DISCUSSION: In total there were 77 respondents and the mean age was 48.8 (SD 17.63, range 20-82) years. There were 52% women and 48% men. Major complications, such as not undergoing the procedure, future management and long-term effect on work, all scored a median of 95%. Least concerns were related to technical details of the procedure and minor complications (median 64% and 63%, respectively). All other questions were still considered important (median 79-93%). No significant differences were observed between sex, age and professional groups, but a significant difference was observed between the education groups. Qualifications of the doctor did not correlate to any other question. CONCLUSIONS: This questionnaire is proposed as a basis for informed consent guidelines to health workers and for measures of satisfaction with the consent procedure.

Adhesive capsulitis of the shoulder: the rate of manipulation following distension arthrogram.

To determine the rate of manipulation under anaesthesia (MUA) following distension arthrogram for adhesive capsulitis of the shoulder. Thirty-nine patients (42 shoulders) between 1998 and 2004 were treated with distension arthrogram for adhesive capsulitis diagnosed by the clinical picture of progressive pain and stiffness. Capsular disruption into the subscapular bursa was demonstrated in 40 of the 42 shoulders (95%). Thirty-seven of 42 (88%) shoulders were painfree following distension arthrogram. 15 of 42 (36%) shoulders underwent MUA following distension arthrogram for stiffness although 10 of these (67%) were painfree. Prior to distension arthrogram, the range of external rotation (ER) was no different between those that had MUA and those that did not (P = 0.36). The improvement in ER was 33% (P = 0.28) in those that had MUA and 50% (P = 0.001) in those that did not. The only complication was a vasovagal episode during the procedure. Distension arthrogram can be used as a therapeutic procedure for achieving symptomatic pain relief in the majority of adhesive capsulitis and decrease the rate of MUA of the shoulder.

Trauma rapid review process: efficient out-patient fracture management.

INTRODUCTION: Our hospital operates a consultant-led, rapid review process of X-rays and case notes of all musculoskeletal injury patients on a daily basis. This compares with other centres where patients are reviewed in out-patient fracture clinics soon after injury. The aim of this study was to evaluate the effectiveness of this consultant-led, rapid review process compared to standard consultant fracture clinics. PATIENTS AND METHODS: A prospective study of the rapid review process over 4 weeks of all musculoskeletal injury patients was conducted. The total number of patients referred per day, time taken to review these patients X-rays and case notes, number of recalls and reason for recall were documented. This was compared to consultant-led fracture clinics, which included time taken to review patients. RESULTS: A total of 797 patients were processed through the rapid review over 4 weeks: 53 (6%) patients were recalled, 32 (4%) for a change of management and 21 (2.6%) because of lack of information. The mean number of patients referred per day was 28 taking a mean of 28 min; thus the mean time to review one patient was 1.0 min. The mean number of patients recalled per day was two. The mean time taken to review a patient in a standard fracture clinic was 11 min. Therefore, the total time that would have taken to review 28 patients in a standard fracture clinic would be 308 min. CONCLUSIONS: A consultant-led, rapid review process of all patients with musculoskeletal injury is a very efficient process. The rapid review process saves clinic time and resources, minimises delays in clinical decision-making and saves the patient an unnecessary visit to the outpatient department.

The effect of high dose atorvastatin therapy on lipids and lipoprotein subfractions in overweight patients with type 2 diabetes.

Few data are available on the effects of high dose statin therapy on lipoprotein subfractions in type 2 diabetes. In a double blind randomised placebo-controlled trial we have studied the effects of 80 mg atorvastatin over 8 weeks on LDL, VLDL and HDL subfractions in 40 overweight type 2 diabetes patients. VLDL and LDL subfractions were prepared by density gradient ultracentrifugation. Triglycerides, cholesterol, total protein and phospholipids were measured and mass of subfractions calculated. HDL subfractions were prepared by precipitation. Atorvastatin 80 mg produced significant falls in LDL subfractions (LDL(1) 66.2 mg/dl:36.6 mg/dl, LDL(2) 118:56.6 mg/dl, LDL(3) 36.9:19.9 mg/dl all P < 0.01 relative to placebo) and VLDL subfractions (VLDL(1) 55:22.1 mg/dl, VLDL(2) 40.1:19.1 mg/dl, VLDL(3) 52.6:30 mg/dl all P < 0.01 relative to placebo). There was no change in the proportion of LDL present as LDL(3). There was a reduction in the proportion of VLDL as VLDL(1) and a reciprocal increase in the proportion as VLDL(3). Changes in VLDL subfractions were associated with changes in lipid composition, particularly a reduction in cholesterol ester and a reduction in the cholesterol ester/triglyceride ratio. Effects on HDL subfractions were largely neutral. High dose atorvastatin produces favourable effects on lipoprotein subfractions in type 2 diabetes which may enhance antiatherogenic potential.

Reverse genetic analysis of the glutathione metabolic pathway suggests a novel role of PHGPX and URE2 genes in aluminum resistance in Saccharomyces cerevisiae.

We have taken a systematic genetic approach to study the potential role of glutathione metabolism in aluminum (Al) toxicity and resistance, using disruption mutants available in Saccharomyces cerevisiae. Yeast disruption mutants defective in phospholipid hydroperoxide glutathione peroxidases (PHGPX; phgpx1 Delta, phgpx2 Delta, and phgpx3Delta), were tested for their sensitivity to Al. The triple mutant, phgpx1 Delta/2Delta/3Delta, was more sensitive to Al (55% reduction in growth at 300 microM Al) than any single phgpx mutant, indicating that the PHGPX genes may collectively contribute to Al resistance. The hypersensitivity of phgpx3Delta to Al was overcome by complementation with PHGPX3, and all PHGPX genes showed increased expression in response to Al in the wild-type strain (YPH250), with maximum induction of approximately 2.5-fold for PHGPX3. Both phgpx3Delta and phgpx1Delta/2Delta/3Delta mutants were sensitive to oxidative stress (exposure to H(2)O(2) or diamide). Lipid peroxidation was also increased in the phgpx1Delta/2Delta/3Delta mutant compared to the parental strain. Disruption mutants defective in genes for glutathione S-transferases (GSTs) (gtt1Delta and gtt2Delta), glutathione biosynthesis (gsh1Delta and gsh2Delta), glutathione reductase (glr1Delta) and a glutathione transporter (opt1Delta) did not show hypersensitivity to Al relative to the parental strain BY4741. Interestingly, a strain deleted for URE2, a gene which encodes a prion precursor with homology to GSTs, also showed hypersensitivity to Al. The hypersensitivity of the ure2Delta mutant could be overcome by complementation with URE2. Expression of URE2 in the parental strain increased approximately 2-fold in response to exposure to 100 microM Al. Intracellular oxidation levels in the ure2Delta mutant showed a 2-fold (non-stressed) and 3-fold (when exposed-to 2 mM H(2)O(2)) increase compared to BY4741; however, the ure2Delta mutant showed no change in lipid peroxidation compared to the control. The phgpx1Delta/2Delta/3Delta and ure2Delta mutants both showed increased accumulation of Al. These findings suggest the involvement of PHGPX genes and a novel role of URE2 in Al toxicity/resistance in S. cerevisiae.

Body-exhaust suit versus occlusive clothing. A randomised, prospective trial using air and wound bacterial counts.

We randomly allocated 50 total knee replacements to scrub teams wearing body-exhaust suits (BES) or Rotecno occlusive clothing. The effectiveness of the clothing was assessed using air andwound bacterial counts. Bacteria were recovered from 62% of wounds (64% BES, 60% Rotecno). The mean air count was 0.5 CFU/ m3 with BES and 1.0 CFU/m3 with Rotecno (p = 0.014). The mean wound counts were 14 bacteria/wound with BES and eight bacteria/wound with Rotecno (p = 0.171). There was no correlation between the air and wound counts (r = -0.011, Spearman's). The higher air counts suggest that Rotecno occlusive clothing is less effective than BES, but wounds were equally contaminated with both types of clothing suggesting that at very low levels of air contamination the contribution of bacteria to the wound from the air is irrelevant. Even doubling the air counts from 0.5 to 1.0 CFU/m3 had no detectable effect on the wound. This allows a reassessment to be made of other sources of contamination the effect of which would previously have been overwhelmed by contamination from air.