The pseudokinase TRIB3 controls adipocyte lipid homeostasis and proliferation in vitro and in vivo

OBJECTIVE

In vivo studies in humans and mice have implicated the pseudokinase Tribbles 3 (TRIB3) in various aspects of energy metabolism. Whilst cell-based studies indicate a role for TRIB3 in adipocyte differentiation and function, it is unclear if and how these cellular functions may contribute to overall metabolic health.

METHODS

We investigated the metabolic phenotype of whole-body Trib3 knockout (Trib3KO) mice, focusing on adipocyte and adipose tissue functions. In addition, we combined lipidomics, transcriptomics, interactomics and phosphoproteomics analyses to elucidate cell-intrinsic functions of TRIB3 in pre- and mature adipocytes.

RESULTS

Trib3KO mice display increased adiposity, but their insulin sensitivity remains unaltered. Trib3KO adipocytes are smaller and display higher Proliferating Cell Nuclear Antigen (PCNA) levels, indicating potential alterations in either i) proliferation-differentiation balance, ii) impaired expansion after cell division, or iii) an altered balance between lipid storage and release, or a combination thereof. Lipidome analyses suggest TRIB3 involvement in the latter two processes, as triglyceride storage is reduced and membrane composition, which can restrain cellular expansion, is altered. Integrated interactome, phosphoproteome and transcriptome analyses support a role for TRIB3 in all three cellular processes through multiple cellular pathways, including Mitogen Activated Protein Kinase- (MAPK/ERK), Protein Kinase A (PKA)-mediated signaling and Transcription Factor 7 like 2 (TCF7L2) and Beta Catenin-mediated gene expression.

CONCLUSIONS

Our findings support TRIB3 playing multiple distinct regulatory roles in the cytoplasm, nucleus and mitochondria, ultimately controlling adipose tissue homeostasis, rather than affecting a single cellular pathway.

147 ESTABLISHING A PERI-OPERATIVE MEDICAL SERVICE (POMS) FOR OLDER PEOPLE IN UROLOGY

Background

Older adults account for approximately 65% of patients undergoing urological procedures therefore as the population ages the demand is anticipated to rise. The benefits of Comprehensive Geriatric Assessment (CGA) have been proven in ortho-geriatrics and a number of surgical specialties but evidence in urology is lacking. The aim of this study was to assess the impact of a Peri-Operative Medical Service for older people (POMS) on patient outcomes in a urology inpatient population.

Methods

This was a single-centre retrospective study of patients ≥50 years with length of stay (LOS) >1 day admitted over two four month periods in 2018 (Pre-intervention) and 2019 (Intervention). Group differences in LOS and complications were examined using univariate regressions and then adjusted for sex, emergency admission, severity of procedure and Charlson Co-morbidity Index which also accounts for age. Secondary outcomes were to record undiagnosed medical conditions identified and the interventions made by the POMS.

Results

There were a total of 218 admissions from 211 patients with equal numbers of admissions in both the pre-intervention and intervention groups. No significant differences were detected for LOS (median 3 vs 4 days, p=0.11) or complications (32(29%) vs 40(37%), p=0.23) between pre-intervention and intervention groups. A new medical diagnosis was made in 13 (12%) of the pre-intervention v 43(39%) of the intervention group (p<0.001). The POMS recommended a change to management in 102 admissions (94%). The most common intervention was medication review: 64(59%) v 19(17%) (p<0.001).

Conclusion

The Peri-Operative Medical Service for older people can improve patient management by identifying and managing medical issues, complications and geriatric syndromes that may otherwise have been missed.

Effect of Probiotics on Incident Ventilator-Associated Pneumonia in Critically Ill Patients: A Randomized Clinical Trial

IMPORTANCE

Growing interest in microbial dysbiosis during critical illness has raised questions about the therapeutic potential of microbiome modification with probiotics. Prior randomized trials in this population suggest that probiotics reduce infection, particularly ventilator-associated pneumonia (VAP), although probiotic-associated infections have also been reported.

OBJECTIVE

To evaluate the effect of Lactobacillus rhamnosus GG on preventing VAP, additional infections, and other clinically important outcomes in the intensive care unit (ICU).

DESIGN, SETTING, AND PARTICIPANTS

Randomized placebo-controlled trial in 44 ICUs in Canada, the United States, and Saudi Arabia enrolling adults predicted to require mechanical ventilation for at least 72 hours. A total of 2653 patients were enrolled from October 2013 to March 2019 (final follow-up, October 2020).

INTERVENTIONS

Enteral L rhamnosus GG (1 × 1010 colony-forming units) (n = 1321) or placebo (n = 1332) twice daily in the ICU.

MAIN OUTCOMES AND MEASURES

The primary outcome was VAP determined by duplicate blinded central adjudication. Secondary outcomes were other ICU-acquired infections including Clostridioides difficile infection, diarrhea, antimicrobial use, ICU and hospital length of stay, and mortality.

RESULTS

Among 2653 randomized patients (mean age, 59.8 years [SD], 16.5 years), 2650 (99.9%) completed the trial (mean age, 59.8 years [SD], 16.5 years; 1063 women [40.1%.] with a mean Acute Physiology and Chronic Health Evaluation II score of 22.0 (SD, 7.8) and received the study product for a median of 9 days (IQR, 5-15 days). VAP developed among 289 of 1318 patients (21.9%) receiving probiotics vs 284 of 1332 controls (21.3%; hazard ratio [HR], 1.03 (95% CI, 0.87-1.22; P = .73, absolute difference, 0.6%, 95% CI, -2.5% to 3.7%). None of the 20 prespecified secondary outcomes, including other ICU-acquired infections, diarrhea, antimicrobial use, mortality, or length of stay showed a significant difference. Fifteen patients (1.1%) receiving probiotics vs 1 (0.1%) in the control group experienced the adverse event of L rhamnosus in a sterile site or the sole or predominant organism in a nonsterile site (odds ratio, 14.02; 95% CI, 1.79-109.58; P < .001).

CONCLUSIONS AND RELEVANCE

Among critically ill patients requiring mechanical ventilation, administration of the probiotic L rhamnosus GG compared with placebo, resulted in no significant difference in the development of ventilator-associated pneumonia. These findings do not support the use of L rhamnosus GG in critically ill patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02462590.

Cardiopulmonary Exercise Testing in Oesophagogastric Surgery: a Systematic Review

BACKGROUND

Cardiopulmonary exercise testing (CPX) can objectively measure fitness and oxygen uptake at anaerobic threshold. The relationship between fitness and postoperative outcomes after upper gastro-intestinal surgery is unclear. The aim of the present review is to assess the prognostic ability of CPX in predicting postoperative outcome associated with oesophagogastric surgery.

METHODS

Relevant studies were identified through a systematic search of EMBASE, Medline, CINAHL, Cochrane Library, and Web of Science to July 2019. The eligibility criteria for studies included prognostic studies of upper gastro-intestinal surgery among adult populations using a preoperative CPX and measurement of postoperative outcome (mortality or morbidity or length of stay). Risk of bias was assessed using the QUIPS Quality in Prognostic Studies validated tool.

RESULTS

Thirteen papers with a total of 1735 participants were included in data extraction. A total of 7 studies examined the association between CPX variables and postoperative mortality. Patients undergoing gastro-intestinal surgery with lower anaerobic threshold values were found to have an increased risk of postoperative mortality. Similarly, a lower rate of oxygen consumption was found to be associated with higher mortality. There was conflicting evidence regarding the association between CPX variables and postoperative morbidity. The evidence did not demonstrate any association between preoperative CPX variables and hospital length of stay.

CONCLUSION

Studies report an association between CPX variables and postoperative mortality; however, there is conflicting evidence regarding the association between CPX variables and postoperative morbidity.

Probing human sperm metabolism using 13C-magnetic resonance spectroscopy

STUDY QUESTION

Can 13C-Magnetic Resonance Spectroscopy (MRS) of selected metabolites provide useful information about human sperm metabolism and how glycolysis or oxidative phosphorylation are used by different sperm populations?

SUMMARY ANSWER

Sperm populations, prepared by density gradient centrifugation (DGC) and incubated with either 13Cu-glucose, 13Cu-fructose or 13C1-pyruvate, showed consistent evidence of metabolism generating principally lactate and more intermittently bicarbonate, and significantly more lactate was produced from 13Cu-glucose by vital or motile sperm recovered from the 40/80% interface compared to those from the pellet, which could not be accounted for by differences in the non-sperm cells present.

WHAT IS KNOWN ALREADY

Previous studies have focused on CO2 or other specific metabolite production by human sperm and there remains considerable debate about whether glycolysis and/or oxidative phosphorylation is the more important pathway for ATP production in sperm.

STUDY DESIGN, SIZE, DURATION

Sperm populations were prepared by DGC and subjected to 13C-MRS to answer the following questions. (i) Is it possible to detect human sperm metabolism of 13C substrates implicated in energy generation? (ii) What are the kinetics of such reactions? (iii) Do different sperm populations (e.g. '80%' pellet sperm and '40%' interface sperm) utilise substrates in the same way? Semen samples from 97 men were used in these experiments; 52 were used in parallel for aims (i) and (ii) and 45 were used for aim (iii).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Sperm populations were prepared from ejaculates of healthy men using a Percoll/Phosphate Buffered Saline (PBS) DGC and then incubated with a range of 13C-labelled substrates (13Cu-glucose, 13Cu-fructose, 13C1-pyruvate, 13C1-butyrate, 13C3-lactate, 13C2,4-D-3-hydroxybutyrate, 13C5-l-glutamate, 13C1,2-glycine or 13Cu-galactose) along with penicillin/streptomycin antibiotic at 37°C for 4 h, 24 h or over 48 h for an estimated rate constant. Sperm concentration, vitality and motility were measured and, for a subset of experiments, non-sperm cell concentration was determined. A 9.4 T magnetic resonance spectrometer was used to acquire 1D 13C, inverse gated 1H decoupled, MRS spectra. Spectrum processing was carried out using spectrometer software and Matlab scripts to determine peak integrals for each spectrum.

MAIN RESULTS AND THE ROLE OF CHANCE

13Cu-glucose, 13Cu-fructose and 13C1-pyruvate were consistently converted into lactate and, to a lesser extent, bicarbonate. There was a significant correlation between sperm concentration and lactate peak size for 13Cu-glucose and 13Cu-fructose, which was not observed for 13C1-pyruvate. The lactate peak did not correlate with the non-sperm cell concentration up to 6.9 × 106/ml. The concentration of 13Cu-glucose, 13Cu-fructose or 13C1-pyruvate (1.8, 3.6, 7.2 or 14.4 mM) had no influence on the size of the observed lactate peak over a 4 h incubation. The rate of conversion of 13C1-pyruvate to lactate was approximately three times faster than for 13Cu-glucose or 13Cu-fructose which were not significantly different from each other. After incubating for 4 h, the utilisation of 13Cu-glucose, 13Cu-fructose or 13C1-pyruvate by sperm from the '40%' interface of the DGC was no different from those from the pellet when normalised to total sperm concentration. However, after normalising by either the vital or motile sperm concentration, there was a significant increase in conversion of 13Cu-glucose to lactate by '40%' interface sperm compared to pellet sperm (Vital = 3.3 ± 0.30 × 106 vs 2.0 ± 0.21 × 106; P = 0.0049; Motile = 7.0 ± 0.75 × 106 vs 4.8 ± 0.13 × 106; P = 0.0032. Mann-Whitney test P < 0.0055 taken as statistically significant). No significant differences were observed for 13Cu-fructose or 13C1-pyruvate.

LARGE SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

Only 13C labelled metabolites that accumulate to a sufficiently high concentration can be observed by 13C MRS. For this reason, intermediary molecules in the metabolic chain are difficult to observe without trapping the molecule at a particular step using inhibitors. Non-sperm cell concentration was typical of the general population and no link was found between these cells and the magnitude of the 13C-lactate peak. However, it is possible that higher concentrations than the maximum observed (6.9 × 106/ml) may contribute to exogenous substrate metabolism in other experiments.

WIDER IMPLICATIONS OF THE FINDINGS

13C-MRS can provide information on the underlying metabolism of multiple pathways in live sperm. Dysfunction in sperm metabolism, as a result of either impaired enzymes of lack of metabolisable substrate, could be detected in sperm by a non-destructive assay, potentially offering new treatment options to improve overall sperm quality and outcomes for reproduction.

STUDY FUNDING AND COMPETING INTERESTS

This work was supported by the Medical Research Council Grant MR/M010473/1. The authors declare no conflicts of interest.

Convection Oven Determination of Loss of Mass on Drying of Quick Frozen French Fried Potatoes: Collaborative Study

A collaborative study was carried out on one of the methods submitted to the Joint Economic Commission for Europe (ECE)/Codex Alimentarius Commission Group of Experts on the Standardization of Quick Frozen Foods for the determination of moisture in quick frozen french (fried potatoes. The method was based on the determination of loss of mass of the sample on drying in a convection oven 16 h at 103±2°C. Two samples of uncooked quick frozen french fried potatoes and 2 samples of oven quick frozen french fried potatoes were analyzed by 14 and 13 laboratories, respectively. The method is simple and was found to be analytically satisfactory with repeatability and reproducibility values of 0.21 and 2.00 g/100 g french fried potatoes, and 0.29 and 3.00 g/100 g oven french fried potatoes, respectively. The method was adopted by the Group of Experts in preference to other proposed procedures for this determination. The method has been adopted official first action by AOAC.

Migrant status and identification as ultra-high risk for psychosis and transitioning to a psychotic disorder

BACKGROUND

Certain migrant groups are more likely to develop a psychotic disorder compared to the native-born populations, and a younger age at migration is associated with greater risk. However, it is not known at which stage migration has an effect on the development of psychotic disorders. We examined whether migrants were more likely to be identified as ultra-high risk for psychosis (UHR) compared to native-born young people and whether migrant status was associated with the risk of transition to a full-threshold psychotic disorder.

METHODS

The cohort included all young people aged 15-24 who were identified as UHR at a specialist clinic over a five-year period (2012-16). Australian census data were used to obtain the at-risk population. Poisson regression was used to calculate rate ratios and Cox regression analysis determined hazard ratios.

RESULTS

467 young people were identified as UHR, of which 13.5% (n = 63) were born overseas. First-generation migrants were 2.6-fold less likely to be identified as UHR compared to Australian-born young people (IRR = 0.39, 95% CI [0.30, 0.51], P < 0.001). There was no difference between migrant and native-born young people in their risk of transitioning to a psychotic disorder (HR = 0.90, 95% CI [0.39, 2.08], P = 0.81).

CONCLUSIONS

UHR first-generation migrants may be under-accessing mental health services.

1H Magnetic Resonance Spectroscopy of live human sperm

STUDY QUESTION

Can ¹H Magnetic Resonance Spectroscopy (MRS) be used to obtain information about the molecules and metabolites in live human spermatozoa?

SUMMARY ANSWER

Percoll-based density gradient centrifugation (DGC) followed by a further two washing steps, yielded enough sperm with minimal contamination (<0.01%) from seminal fluid to permit effective MRS which detected significant differences (P < 0.05) in the choline/glycerophosphocholine (GPC), lipid and lactate regions of the ¹H MRS spectrum between sperm in the pellet and those from the 40%/80% interface.

WHAT IS KNOWN ALREADY

Current methods to examine sperm are either limited in their value (e.g. semen analysis) or are destructive (e.g. immunohistochemistry, sperm DNA testing). A few studies have previously used MRS to examine sperm, but these have either looked at seminal plasma from men with different ejaculate qualities or at the molecules present in pooled samples of lyophilized sperm.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

Sperm suspended in phosphate buffered saline (PBS) at 37°C were examined by ¹H MRS scanning using a ¹H excitation-sculpting solvent suppression sequence after recovery from fresh ejaculates by one of three different methods: (i) simple centrifugation; (ii) DGC with one wash; or (iii) DGC with two washes. In the case of DGC, sperm were collected both from the pellet (‘80%’ sperm) and the 40/80 interface (‘40%’ sperm). Spectrum processing was carried out using custom Matlab scripts to determine; the degree of seminal plasma/Percoll contamination, the minimum sperm concentration for ¹H MRS detection and differences between the ¹H MRS spectra of ‘40%’ and ‘80%’ sperm.

MAIN RESULTS AND THE ROLE OF CHANCE

DGC with two washes minimized the ¹H MRS peak intensity for both seminal plasma and Percoll/PBS solution contamination while retaining sperm specific peaks. For the MRS scanner used in this study, the minimum sperm concentration required to produce a choline/GPC ¹H MRS peak greater than 3:1 signal to noise ratio (SNR) was estimated at ~3 × 10⁶/ml. The choline/GPC and lactate/lipid regions of the ¹H spectrum were significantly different by two-way ANOVA analysis (P < 0.0001; n = 20). ROC curve analysis of these region showed significant ability to distinguish between the two sperm populations: choline/GPC ROC AUC = 0.65–0.67, lactate/lipid ROC AUC = 0.86–0.87.

LIMITATIONS, REASONS FOR CAUTION

Only 3–4 semen samples were used to assess the efficacy of each sperm washing protocol that were examined. The estimated minimum sperm concentration required for MRS is specific to the hardware used in our study and may be different in other spectrometers. Spectrum binning is a low resolution analysis method that sums MRS peaks within a chemical shift range. This can obscure the identity of which metabolite(s) are responsible for differences between sperm populations. Further work is required to determine the relative contribution of somatic cells to the MRS spectrum from the ‘40%’ and ‘80%’ sperm.

WIDER IMPLICATIONS OF THE FINDINGS

¹H MRS can provide information about the molecules present in live human sperm and may therefore permit the study of the underlying functional biology or metabolomics of live sperm. Given the relatively low concentration of sperm required to obtain a suitable MRS signal (~3 × 10⁶/ml), this could be carried out on sperm from men with oligo-, astheno- or teratozoospermia. This may lead to the development of new diagnostic tests or ultimately novel treatments for male factor infertility.

STUDY FUNDING AND COMPETING INTEREST(S)

This work was supported by the Medical Research Council Grant MR/M010473/1. The authors declare no conflicts of interest.

An approach for the identification of exemplar sites for scaling up targeted field observations of benthic biogeochemistry in heterogeneous environments

Continental shelf sediments are globally important for biogeochemical activity. Quantification of shelf-scale stocks and fluxes of carbon and nutrients requires the extrapolation of observations made at limited points in space and time. The procedure for selecting exemplar sites to form the basis of this up-scaling is discussed in relation to a UK-funded research programme investigating biogeochemistry in shelf seas. A three-step selection process is proposed in which (1) a target area representative of UK shelf sediment heterogeneity is selected, (2) the target area is assessed for spatial heterogeneity in sediment and habitat type, bed and water column structure and hydrodynamic forcing, and (3) study sites are selected within this target area encompassing the range of spatial heterogeneity required to address key scientific questions regarding shelf scale biogeochemistry, and minimise confounding variables. This led to the selection of four sites within the Celtic Sea that are significantly different in terms of their sediment, bed structure, and macrofaunal, meiofaunal and microbial community structures and diversity, but have minimal variations in water depth, tidal and wave magnitudes and directions, temperature and salinity. They form the basis of a research cruise programme of observation, sampling and experimentation encompassing the spring bloom cycle. Typical variation in key biogeochemical, sediment, biological and hydrodynamic parameters over a pre to post bloom period are presented, with a discussion of anthropogenic influences in the region. This methodology ensures the best likelihood of site-specific work being useful for up-scaling activities, increasing our understanding of benthic biogeochemistry at the UK-shelf scale.

Association between optic nerve sheath diameter and mortality in patients with severe traumatic brain injury

PURPOSE

Increased intracranial pressure (ICP) is associated with worse outcomes following traumatic brain injury (TBI). Studies have confirmed that ICP is correlated with optic nerve sheath diameter (ONSD) on ultrasound. The aim of our study was to assess the independent relationship between ONSD measured using CT and mortality in a population of patients admitted with severe TBI.

METHODS

We conducted a retrospective cohort study of patients with a TBI requiring ICP monitoring admitted to the ICU between April 2006 and May 2012 to two neurotrauma centers. ONSD was independently measured by two physicians blinded to patient outcomes. Multivariable logistic regression modeling was used to assess an association between ONSD and hospital mortality.

RESULTS

A total of 220 patients were included in the analysis. Overall, the cohort had a mean age of 35 (SD 17) years and 171 of 220 (79 %) were male. The median admission GCS was 6 (IQR 3-8). Intra-class correlation coefficient between raters for ONSD measurements was 0.92 (95 % CI 0.90-0.94, P < 0.0001). On multivariable analysis, each 1 mm increase in ONSD was associated with a twofold increase in hospital mortality (OR 2.0, 95 % CI 1.2-3.2, P = 0.007). Using linear regression, ONSD was independently associated with increased ICP in the first 48 h after admission (β = 4.4, 95 % CI 2.5-6.3, P < 0.0001).

CONCLUSIONS

In patients with TBI, ONSD measured on CT scanning was independently associated with ICP and mortality.

Thiopurine withdrawal during sustained clinical remission in inflammatory bowel disease: relapse and recapture rates, with predictive factors in 237 patients

BACKGROUND

Thiopurines (azathioprine and mercaptopurine) remain integral to most medical strategies for maintaining remission in Crohn's disease (CD) and ulcerative colitis (UC). Indefinite use of these drugs is tempered by long-term risks. While clinical relapse is noted frequently following drug withdrawal, there are few published data on predictive factors.

AIM

To investigate the success of planned thiopurine withdrawal in patients in sustained clinical remission to identify rates and predictors of relapse.

METHODS

This was a multicentre retrospective cohort study from 11 centres across the UK. Patients included had a definitive diagnosis of IBD, continuous thiopurine use ≥3 years and withdrawal when in sustained clinical remission. All patients had a minimum of 12 months follow-up post drug withdrawal. Primary and secondary end points were relapse at 12 and 24 months respectively.

RESULTS

237 patients were included in the study (129 CD; 108 UC). Median duration of thiopurine use prior to withdrawal was 6.0 years (interquartile range 4.4-8.4). At follow-up, moderate/severe relapse was observed in 23% CD and 12% UC patients at 12 months, 39% CD and 26% UC at 24 months. Relapse rate at 12 months was significantly higher in CD than UC (P = 0.035). Elevated CRP at withdrawal was associated with higher relapse rates at 12 months for CD (P = 0.005), while an elevated white cell count was predictive at 12 months for UC (P = 0.007).

CONCLUSION

Thiopurine withdrawal in the context of sustained remission is associated with a 1-year moderate-to-severe relapse rate of 23% in Crohn's disease and 12% in ulcerative colitis.

Kinetic modeling of hyperpolarized (13)C pyruvate metabolism in tumors using a measured arterial input function

Mathematical models are required to estimate kinetic parameters of [1-(13)C] pyruvate-lactate interconversion from magnetic resonance spectroscopy data. One- or two-way exchange models utilizing a hypothetical approximation to the true arterial input function (AIF), (e.g. an ideal 'box-car' function) have been used previously. We present a method for direct measurement of the AIF in the rat. The hyperpolarized [1-(13)C] pyruvate signal was measured in arterial blood as it was continuously withdrawn through a small chamber. The measured signal was corrected for T1 relaxation of pyruvate, RF pulses and dispersion of blood in the chamber to allow for the estimation of the direct AIF. Using direct AIF, rather than the commonly used box-car AIF, provided realistic estimates of the rate constant of conversion of pyruvate to lactate, kpl, the rate constant of conversion of lactate to pyruvate klp, the clearance rate constant of pyruvate from blood to tissue, Kip, and the relaxation rate of lactate T1la. Since no lactate signal was present in blood, it was possible to use a simple precursor-product relationship, with the tumor tissue pyruvate time-course as the input for the lactate time-course. This provided a robust estimate of kpl, similar to that obtained using a directly measured AIF.

Interpretation of Transient Photocurrents in Coplanar and Sandwich PIN Microcrystalline Silicon Structures

We report on the use of coplanar transient photoconductivity and post-transit time-of-flight spectroscopy techniques in the study of carrier transport in microcrystalline silicon films prepared over a range of crystallinities. Coplanar samples are susceptible to post-deposition oxidation and reversible adsorption of atmospheric gases, which may alter the apparent density of states. Coplanar measurements suggest lower deep defect densities in more highly crystalline films, but this is due at least in part to an increased occupancy of these states. A comparison of results obtained using both techniques suggests anisotropic transport, with reduced band tailing (greater structural order) along the direction of film growth, a larger defect concentration around the column boundaries, and a higher defect density within the amorphous tissue than in optimised single-component amorphous silicon films.

Extension of the Constant Photocurrent Method to Determine Densities of Occupied and Unoccupied Localised States

This paper examines the use of Constant Photocurrent (CPM) measurements on thin film semiconductors, employing steady (DC) and modulated (AC) sub-gap illumination, to determine the density of localised states (DOS) in the bandgap. AC and DC measurements often result in different apparent absorption spectra. It is demonstrated that it is possible not only to extract information from the respective 'absorption' spectra, on the DOS below the Fermi level - i.e. occupied states, but also on the density of unoccupied states above the Fermi level. The ability to discriminate between these two groups of states by using DC and AC modulated sub-gap light arises from the frequency dependence of the different excitation pathways by which free electrons can be produced. AC modulated excitation will reveal absorption associated with transitions from occupied states into the conduction band, while DC excitation will include transitions from the valence band into unoccupied defect states, followed by slow thermal emission to the conduction band. We examine the temperature dependence of the CPM spectra and present a simple analysis of the DC and AC absorption spectra which allows the two regions of the DOS, above and below the Fermi level, to be determined.

Setting up a store‐and‐forward telemedicine service for acute trauma in a hospital trust

Telemedicine is a valuable, but as yet underused, resource for the delivery of health-care to patients. This paper describes the development of a new store-and-forward telemedicine service at the Queen Victoria Hospital, which is a tertiary referral centre for plastic surgery in the United Kingdom. The practical requirements of such a system, and the technical and legal difficulties experienced during the initial stages, are also discussed.

Community-associated CMRSA-10 (USA-300) is the predominant strain among methicillin-resistant Staphylococcus aureus strains causing skin and soft tissue infections in patients presenting to the emergency department of a Canadian tertiary care hospital

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging pathogen first described among individuals with no contact with health care facilities. The purpose of this study was to determine the proportion of CA-MRSA, defined by pulsed field gel electrophoresis (PFGE), in MRSA skin and soft tissue infections presenting to the Emergency Department (ED). We also aimed to describe the laboratory and clinical characteristics of CA-MRSA infections. From June 1, 2001 to May 30, 2005, MRSA isolates from skin and soft tissue infections presenting to the ED were reviewed. They were characterized by antibiotic susceptibilities and PFGE, and the presence of staphylococcal cassette chromosome (SCC) mec type IVa and Panton-Valentine leukocidin (PVL) genes was assessed on representative isolates. The medical records were reviewed to define risk factors. There were 95 isolates available for analysis, of which 58 (61%) were CMRSA-10 (USA-300), the predominant clone from 2003 onward. All representative isolates (24%) tested in this group had PVL genes and SCCmec type IVa. Their antibiogram showed 100% susceptibility to trimethoprim-sulfamethoxazole, rifampin, and fusidic acid, and 79% to clindamycin. Clinical comparison of CMRSA-10 vs. hospital PFGE type strains showed 22% vs. 60%, respectively, for recent antibiotic use (p < 0.0001), 26% vs. 6%, respectively, for intravenous drug use (p < 0.05), and 57% vs. 6%, respectively, for soft tissue abscess (p < 0.001). CMRSA-10 is a major pathogen in skin and soft tissue abscesses in our ED. It has a characteristic susceptibility, and was associated with intravenous drug use, but not with recent antibiotic usage.

Social domain dysfunction and disorganization in borderline personality disorder

BACKGROUND

Social dysfunction in personality disorder is commonly ascribed to abnormal temperamental traits but may also reflect deficits in social processing. In this study, we examined whether borderline and avoidant personality disorders (BPD, APD) may be differentiated by deficits in different social domains and whether disorganization of social domain functioning uniquely characterizes BPD.

METHOD

Patients were recruited from psychiatric clinics in Pittsburgh, USA, to provide a sample with BPD, APD and a no-personality disorder (no-PD) comparison group. Standardized assessments of Axis I and Axis II disorders and social domain dysfunction were conducted, including a new scale of 'domain disorganization' (DD).

RESULTS

Pervasive social dysfunction was associated with a 16-fold increase in the odds of an Axis II disorder. Both APD and BPD were associated with elevated social dysfunction. Romantic relationship dysfunction was associated specifically with BPD symptoms and diagnosis. DD was associated specifically with a categorical BPD diagnosis and with a dimensional BPD symptom count.

CONCLUSIONS

A focus on the inherently interpersonal properties of personality disorders suggests specific mechanisms (within and across interpersonal domains) that may help to account for the origins and maintenance of some disorders. In particular, BPD reflects disturbances in romantic relationships, consistent with a role for attachment processes, and in the organization of functioning across social domains.