Longitudinal predictors of post-exposure prophylaxis awareness among latino sexual minority men in South Florida

Biomedical tools for HIV prevention such as post-exposure prophylaxis (PEP) continue to be underutilized by subgroups experiencing significant HIV inequities. Specifically, factors associated with both PEP awareness and uptake both cross-sectionally and longitudinally are under-researched, despite PEP being a part of the United States' Plan for Ending the HIV Epidemic. The current study examined longitudinal predictors of PEP awareness among Latino sexual minority men (LSMM) living in South Florida. This current study (N = 290) employed hierarchal linear modeling across three timepoints (baseline, 4-months, 8-months) to assess within-person and between-person effects over time for several psychosocial and structural factors. Most participants (67.5%) reported little to no awareness of PEP at baseline with general PEP awareness growing slightly across the study (60.5% reporting little to no awareness of PEP at 8 months). Results of the final conditional model suggest significant within-person effects of PrEP knowledge (p = 0.02) and PrEP self-efficacy (p < 0.001), as well as a significant positive between-person effect of PrEP knowledge (p < 0.01) on PEP awareness. Between-person HIV knowledge was also a significant predictor in this model (p = 0.01). This longitudinal analysis of LSMM's PEP awareness indicates that more must be done to increase PEP awareness among this subgroup. Future studies should explore how to build on existing interventions focused on HIV and PrEP knowledge and PrEP self-efficacy to incorporate information about PEP to increase the reach of this effective biomedical HIV prevention tool.

Factors Associated with Antiretroviral Therapy Adherence Among a Community-Based Sample of Sexual Minority Older Adults with HIV

Older sexual minorities (e.g., gay, bisexual) living with HIV are at risk for poor HIV outcomes due to their frequent experience with both psychosocial challenges and structural barriers to care. This study utilized a stochastic search variable selection (SVSS) approach to explore potential psychosocial and structural factors associated with HIV-related health outcomes among a community-based sample of older sexual minorities (N = 150) in South Florida, an U.S. HIV-epidemic epicenter. After SVSS, a forward entry regression approach suggested unstable housing, illicit substance use, current nicotine use, and depression were all associated with poorer ART adherence among older sexual minority adults living with HIV. No associations between potential correlates and biological measures of HIV disease severity were observed. Findings highlight a need to focus on multiple levels of intervention that target a combination of psychosocial and structural factors to improve HIV-care outcomes among older sexual minorities and achieve Ending the HIV Epidemic goals.

Factors Associated with Post-Exposure Prophylaxis Awareness Among Latino Sexual Minority Men in South Florida

Despite their efficacy, biomedical HIV prevention tools such as post-exposure prophylaxis (PEP) and pre-exposure prophylaxis (PrEP) have been insufficiently scaled up and disseminated, especially among marginalized subgroups that face substantial HIV disparities. Given the minimal literature available on PEP among Latino sexual minority men (LSMM), this cross-sectional secondary analysis explored factors associated with PEP awareness among a group of LSMM living in South Florida, a US HIV epicenter. The parent study examined patterns of engagement in PrEP and behavioral health treatment services among LSMM (N = 290). The current secondary analysis (N = 243) identified factors associated with PEP awareness using three methods: stochastic search variable selection, participatory data science, and literature review-before being modeled using linear regression. Most participants (67.5%) reported having little to no awareness about PEP before initiating our study. Simple linear regression models suggested that higher PrEP knowledge (B = 0.17, SE = 0.02, p < 0.001), HIV knowledge (B = 0.15, SE = 0.04, p < 0.001), PrEP self-efficacy (B = 0.37, SE = 0.13, p < 0.05), and high perceived community norms for HIV testing (B = 0.29, SE = 0.14, p < 0.05) were each associated with LSMM's greater PEP awareness, while identity affirmation was associated with less PEP awareness (B = -0.13, SE = 0.05, p < 0.01). Results suggest the utility of our three-pronged variable selection approach and address gaps in PEP awareness and use among LSMM living in a US HIV epicenter to support Ending the HIV Epidemic goals.

Dancing in the rain: how do abiotic conditions influence sexually selected behaviors in the White-ruffed Manakin?

Tropical animals respond to rainfall in population-specific ways. In extremely wet regions, endotherms experience heavy rains as stressors with consequences for behavior and demography. Ultimately, such stressors can affect the relative strength of abiotic selection, reducing the scope for sexual selection and other biotic sources of selection. We studied population-level differences in the response to rainfall in White-ruffed Manakins (Corapipo altera) on the Caribbean slope of Costa Rica, a species having a lek mating system subject to strong sexual selection. Between 2008 and 2013, we studied reproductive behavior in a population inhabiting an extremely wet site; estimates of apparent survival were low, and the turnover of display courts and dominant males was high. Males also engaged in coordinated display, and sub-adult males practiced in the presence of adults. Over three breeding seasons (2017-2019), we studied a population of the same species at a site only 110 km away, but in a location receiving roughly half as much rain. We tested behavioral predictions of three alternative mechanisms-indirect abiotic effects, direct mortality effects, and direct behavioral effects-linking rainfall to sexual selection in these two populations. Data derived from over 4300 hr of observations at 105 display sites revealed high interannual variation in nearly all response variables, including turnover of display sites, retention of alpha status, male display behavior, and time females spent assessing male display. Additionally, we detected spatial differences in drivers of display site turnover. Notably, age distribution of males was skewed toward older individuals at the drier location. Based on these findings we infer that indirect abiotic effects on forest structure leading to display site transience and direct effects of mortality increasing turnover in the male population likely underlie links between rain and the spatial and temporal differences we documented. Our results are consistent with rain constituting an important source of abiotic selection for tropical endotherms and modulating the scope for sexual selection near the extremes of a species' hygric niche.

Value of Xenografts in the Investigation of Prostatic Function: Preliminary Communication

Two of 33 prostatic tumour xenografts were established and passaged. Testosterone supplementation did not improve tumour take rates. The histological grade of the parent tumour was the principal factor affecting xenograft survival. Preliminary studies on established tumour xenografts suggest that their value lies in the study of tumour biology, and that they have no direct therapeutic application at present.

Protective effect of hormone therapy among women with hysterectomy/oophorectomy

Study question

Does exposure to menopausal hormone therapy (MHT) in mid-aged women alter their risk of cardiovascular disease (CVD) mortality and all-cause mortality?

Summary answer

MHT soon after menopause is unlikely to increase the risk of CVD mortality or all-cause mortality and may have a protective effect for women with hysterectomy/oophorectomy.

What is known already

The balance of benefits and risks of MHT are currently unclear and may differ according to when treatment starts and whether women have an intact uterus.

Study design size, duration

A total of 13 715 participants from the mid-aged population-based cohort (born 1946-1951) of the Australian Longitudinal Study on Women's Health (ALSWH) were followed from 1998 to 2013.

Participants/materials setting methods

The measures included cardiovascular and all-cause mortality, exposure to MHT and menopausal status (based on 3-yearly self-reports). Electronic prescriptions data on MHT were also available from mid-2002 onwards. At each follow-up survey wave, participants were classified as: an existing user of MHT, an initiator of MHT or a non-initiator of MHT.

Main results and the role of chance

After adjusting for confounding variables, existing users of MHT had a reduced risk (hazard ratio 0.63; 95% CI, 0.43-0.92) of CVD mortality compared with non-initiators. Insufficient evidence of an association was identified for initiators of MHT (0.66; 0.35-1.24). For all-cause mortality, risks were reduced for both initiators (0.69; 0.55-0.87) and existing users (0.80; 0.70-0.91). In a subgroup analysis, women with hysterectomy/oophorectomy had lower risks of CVD mortality for both initiators (0.14; 0.02-0.98) and existing users (0.55; 0.34-0.90), but no evidence of an association was found for women whose MHT commenced during or after menopause. Similarly for all-cause mortality, only the women with hysterectomy/oophorectomy had lower risks for both initiators (0.47; 0.31-0.70) and existing users (0.69; 0.58-0.82).

Limitations, reasons for caution

Limitations include the observational nature of the study, the small number of deaths, MHT use being self-reported and the classification of menopausal status also being based on self-reported information.

Wider implications of the findings

Women considering MHT soon after menopause can be reassured that the treatment is unlikely to increase their risk of CVD mortality or all-cause mortality.

Study funding/competing interest(s)

The Australian Longitudinal Study on Women's Health is funded by the Australian Department of Health. G.D.M. is funded by the Australian Research Council Future Fellowship. L.C. was funded by a China scholarship council (CSC) graduate scholarship. All authors report no conflict of interest.

Trial registration number

N/A.

Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

The genomic architecture of resistance to Campylobacter jejuni intestinal colonisation in chickens

BACKGROUND

Campylobacter is the leading cause of foodborne diarrhoeal illness in humans and is mostly acquired from consumption or handling of contaminated poultry meat. In the absence of effective licensed vaccines and inhibitors, selection for chickens with increased resistance to Campylobacter could potentially reduce its subsequent entry into the food chain. Campylobacter intestinal colonisation levels are influenced by the host genetics of the chicken. In the present study, two chicken populations were used to investigate the genetic architecture of avian resistance to colonisation: (i) a back-cross of two White Leghorn derived inbred lines [(61 x N) x N] known to differ in resistance to Campylobacter colonisation and (ii) a 9(th) generation advanced intercross (61 x N) line.

RESULTS

The level of colonisation with Campylobacter jejuni following experimental infection was found to be a quantitative trait. A back-cross experiment using 1,243 fully informative single nucleotide polymorphism (SNP) markers revealed quantitative trait loci (QTL) on chromosomes 7, 11 and 14. In the advanced intercross line study, the location of the QTL on chromosome 14 was confirmed and refined and two new QTLs were identified located on chromosomes 4 and 16. Pathway and re-sequencing data analysis of the genes located in the QTL candidate regions identified potential pathways, networks and candidate resistance genes. Finally, gene expression analyses were performed for some of the candidate resistance genes to support the results.

CONCLUSION

Campylobacter resistance in chickens is a complex trait, possibly involving the Major Histocompatibility Complex, innate and adaptive immune responses, cadherins and other factors. Two of the QTLs for Campylobacter resistance are co-located with Salmonella resistance loci, indicating that it may be possible to breed simultaneously for enhanced resistance to both zoonoses.

Genome-wide SNP analysis identifies major QTL for Salmonella colonization in the chicken

Salmonella-infected poultry products are a major source of human Salmonella infection. The prophylactic use of antimicrobials in poultry production was recently banned in the EU, increasing the need for alternative methods to control Salmonella infections in poultry flocks. Genetic selection of chickens more resistant to Salmonella colonization provides an attractive means of sustainably controlling the pathogen in commercial poultry flocks and its subsequent entry into the food chain. Analysis of different inbred chickens has shown that individual lines are consistently either susceptible or resistant to the many serovars of Salmonella that have been tested. In this study, two inbred chicken lines with differential susceptibility to Salmonella colonization (61 ((R)) and N((S)) ) were used in a backcross experimental design. Unlike previous studies that used a candidate gene approach or low-density genome-wide screens, we have exploited a high-density marker set of 1255 SNPs covering the whole genome to identify quantitative trait loci (QTL). Analysis of log-transformed caecal bacterial levels between the parental lines revealed a significant difference at 1, 2, 3 and 4 days post-infection (P < 0.05). Analysis of the genotypes of the backcross (F1  × N) population (n = 288) revealed four QTL on chromosomes 2, 3, 12 and 25 for the two traits examined in this study: log-transformed bacterial counts in the caeca and presence of a hardened caseous caecal core. These included one genome-wide significant QTL on chromosome 2 at 20 Mb and three additional QTL, on chromosomes 3, 12 and 25 at 96, 15 and 1 Mb, respectively, which were significant at the chromosome-wide level (P < 0.05). The results generated in this study will inform future breeding strategies to control these pathogens in commercial poultry flocks.

Campylobacter jejuni gene cj0511 encodes a serine peptidase essential for colonisation

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A novel peptidase Cj0511 in an important human bacterial pathogen Campylobacter jejuni has been characterized.

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Proteolytic properties of Cj0511 protein were detected in whole cell lysates using zymography.

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Enzymatic studies conducted with a purified protein confirmed the prediction of a serine peptidase.

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The cj0511 mutant was severely attenuated in a chicken colonisation model, suggesting a role in infection.

According to MEROPS peptidase database, Campylobacter species encode 64 predicted peptidases. However, proteolytic properties of only a few of these proteins have been confirmed experimentally. In this study we identified and characterised a Campylobacter jejuni gene cj0511 encoding a novel peptidase. The proteolytic activity associated with this enzyme was demonstrated in cell lysates. Moreover, enzymatic studies conducted with a purified protein confirmed a prediction of it being a serine peptidase. Furthermore, cj0511 mutant was found to be severely attenuated in chicken colonisation model, suggesting a role of the Cj0511 protein in infection.

Early immune dynamics following infection with Salmonella enterica serovars Enteritidis, Infantis, Pullorum and Gallinarum: cytokine and chemokine gene expression profile and cellular changes of chicken cecal tonsils

Salmonella enterica subspecies enterica infection remains a serious problem in a wide range of animals and in man. Poultry-derived food is the main source of human infection with the non-host-adapted serovars while fowl typhoid and pullorum disease are important diseases of poultry. We have assessed cecal colonization and immune responses of newly hatched and older chickens to Salmonella serotypes Enteritidis, Infantis, Gallinarum and Pullorum. S. Enteritidis and S. Infantis colonized the ceca more efficiently than S. Gallinarum and S. Pullorum. Salmonella infection was also associated with increased staining for B-lymphocytes and macrophages in the cecal tonsils of infected birds. S. Enteritidis infection in newly hatched birds stimulated the expression of CXCLi1 and CXCLi2 chemokines in the cecal tonsils, while S. Gallinarum up-regulated the expression of LITAF. In older chickens, S. Enteritidis infection resulted in a significantly higher expression of CXCLi2, iNOS, LITAF and IL-10 while S. Pullorum appeared to down-regulate CXCLi1 expression in the cecal tonsils. Data from spleens showed either no expression or down-regulation of the tested genes.

Failures of the Dual Articular knee prosthesis due to fracture of the polyethylene post

The Dual Articular (DA) total knee replacement was designed for revision and complex primary knee arthroplasty. A number of these knees failed due to fracture of the polyethylene post. We aimed to identify the proportion of DA prostheses that failed in this manner in our hospital. The hospital database was interrogated to identify all patients undergoing revision total knee replacement under the care of one surgeon from 1995 to 2007. Case notes were then reviewed to collect information about the history surrounding the knee surgery, and determine the patient's weight at the time of surgery. Telephone follow-up was carried out to obtain complete contemporary data. Forty-eight prostheses were implanted into 39 patients (21 male, 18 female). Thirty-two of the prostheses were DA and of these, 7 underwent arthroscopy or arthrotomy to reveal a fracture of the polyethylene post (22%). T-tests showed no statistical difference in age (p=0.73) or weight (p=0.79) between the group of DA patients with fractured posts and those without. Six of the 7 fractures were in male patients (Chi-squared; p=0.01). Patients complained of pain, clicking and instability at a mean of 7 years post-surgery. Sixteen DA2000 prostheses were implanted, but none of these had failed due to a fractured polyethylene post. A high proportion of DA prostheses failed due to post fracture. We recommend that patients with DA prostheses be kept under review to detect failures early. Pain, clicking and instability should be investigated with arthroscopy and the tibial insert exchanged as appropriate.

Does the use of a "track and trigger" warning system reduce mortality in trauma patients?

INTRODUCTION

Despite the lack of robust evidence, numerous different "track and trigger" warning systems have been implemented. These have only been validated in an emergency medical admissions setting. The Modified Early Warning Score (MEWS) is the chosen track and trigger system used in the University Hospitals of Leicester trauma unit, but has not been validated in trauma patients. A considerable proportion of all trauma admissions are elderly patients with proximal femoral fractures and significant co-morbidities. Early recognition of physiological deterioration and prompt action could therefore be lifesaving in this patient group.

AIM

To identify whether the implementation of the MEWS system coupled with a critical care outreach service resulted in a reduction in mortality in a busy trauma unit.

METHOD

A retrospective study. The MEWS system was implemented in all trauma and orthopaedic wards at the Leicester Royal Infirmary in the summer of 2005. The numbers of emergency trauma inpatient admissions and deaths from January 2002 to December 2009 were obtained. The diagnosis, primary procedures and cause of death, if known, were noted. Comparisons were made pre- and post-MEWS. Student's t-test was used for statistical analysis.

RESULTS

32,149 patients were admitted (55% male; 45% female). Overall there were 889 deaths (77% female; 33% male, P<0.0001). The in-hospital mortality rate for orthopaedic trauma patients was 2.8% throughout the 7-year study period. 61% of those who died were admitted with proximal femoral fractures. The modal age group with the highest mortality was 81-90 years. Overall, females had a considerably greater mortality rate than males. The mortality rate was lower post-MEWS in males (1.82-1.418%; P=0.214), females (4.871-3.364%; P=0.108) and all patients (3.215-2.294%; P=0.092), but this was not statistically significant.

CONCLUSION

The use of a track and trigger warning system has not led to a statistically significant reduction in mortality in trauma patients. In view of the apparent lack of clinical effectiveness of the MEWS/outreach partnership, the cost effectiveness of this initiative needs to be questioned. Possible reasons for these findings include: failure of the MEWS to be correctly applied, inadequate action once the threshold is triggered, or unsuitability of this tool for this patient population. A better system for identifying and treating elderly, medically unwell trauma patients with co-morbidities needs to be developed.

GSTM1 null and NAT2 slow acetylation genotypes, smoking intensity and bladder cancer risk: results from the New England bladder cancer study and NAT2 meta-analysis

Associations between bladder cancer risk and NAT2 and GSTM1 polymorphisms have emerged as some of the most consistent findings in the genetic epidemiology of common metabolic polymorphisms and cancer, but their interaction with tobacco use, intensity and duration remain unclear. In a New England population-based case-control study of urothelial carcinoma, we collected mouthwash samples from 1088 of 1171 cases (92.9%) and 1282 of 1418 controls (91.2%) for genotype analysis of GSTM1, GSTT1 and NAT2 polymorphisms. Odds ratios and 95% confidence intervals of bladder cancer among New England Bladder Cancer Study subjects with one or two inactive GSTM1 alleles (i.e. the 'null' genotype) were 1.26 (0.85-1.88) and 1.54 (1.05-2.25), respectively (P-trend = 0.008), compared with those with two active copies. GSTT1 inactive alleles were not associated with risk. NAT2 slow acetylation status was not associated with risk among never (1.04; 0.71-1.51), former (0.95; 0.75-1.20) or current smokers (1.33; 0.91-1.95); however, a relationship emerged when smoking intensity was evaluated. Among slow acetylators who ever smoked at least 40 cigarettes/day, risk was elevated among ever (1.82; 1.14-2.91, P-interaction = 0.07) and current heavy smokers (3.16; 1.22-8.19, P-interaction = 0.03) compared with rapid acetylators in each category; but was not observed at lower intensities. In contrast, the effect of GSTM1-null genotype was not greater among smokers, regardless of intensity. Meta-analysis of the NAT2 associations with bladder cancer showed a highly significant relationship. Findings from this large USA population-based study provided evidence that the NAT2 slow acetylation genotype interacts with tobacco smoking as a function of exposure intensity.

Improved hospital-level risk adjustment for surveillance of healthcare-associated bloodstream infections: a retrospective cohort study

BACKGROUND

To allow direct comparison of bloodstream infection (BSI) rates between hospitals for performance measurement, observed rates need to be risk adjusted according to the types of patients cared for by the hospital. However, attribute data on all individual patients are often unavailable and hospital-level risk adjustment needs to be done using indirect indicator variables of patient case mix, such as hospital level. We aimed to identify medical services associated with high or low BSI rates, and to evaluate the services provided by the hospital as indicators that can be used for more objective hospital-level risk adjustment.

METHODS

From February 2001-December 2007, 1719 monthly BSI counts were available from 18 hospitals in Queensland, Australia. BSI outcomes were stratified into four groups: overall BSI (OBSI), Staphylococcus aureus BSI (STAPH), intravascular device-related S. aureus BSI (IVD-STAPH) and methicillin-resistant S. aureus BSI (MRSA). Twelve services were considered as candidate risk-adjustment variables. For OBSI, STAPH and IVD-STAPH, we developed generalized estimating equation Poisson regression models that accounted for autocorrelation in longitudinal counts. Due to a lack of autocorrelation, a standard logistic regression model was specified for MRSA.

RESULTS

Four risk services were identified for OBSI: AIDS (IRR 2.14, 95% CI 1.20 to 3.82), infectious diseases (IRR 2.72, 95% CI 1.97 to 3.76), oncology (IRR 1.60, 95% CI 1.29 to 1.98) and bone marrow transplants (IRR 1.52, 95% CI 1.14 to 2.03). Four protective services were also found. A similar but smaller group of risk and protective services were found for the other outcomes. Acceptable agreement between observed and fitted values was found for the OBSI and STAPH models but not for the IVD-STAPH and MRSA models. However, the IVD-STAPH and MRSA models successfully discriminated between hospitals with higher and lower BSI rates.

CONCLUSION

The high model goodness-of-fit and the higher frequency of OBSI and STAPH outcomes indicated that hospital-specific risk adjustment based on medical services provided would be useful for these outcomes in Queensland. The low frequency of IVD-STAPH and MRSA outcomes indicated that development of a hospital-level risk score was a more valid method of risk adjustment for these outcomes.

Acid-base effects of a bicarbonate-balanced priming fluid during cardiopulmonary bypass: comparison with Plasma-Lyte 148. A randomised single-blinded study

Fluid-induced metabolic acidosis can be harmful and can complicate cardiopulmonary bypass. In an attempt to prevent this disturbance, we designed a bicarbonate-based crystalloid circuit prime balanced on physico-chemical principles with a strong ion difference of 24 mEq/l and compared its acid-base effects with those of Plasma-Lyte 148, a multiple electrolyte replacement solution containing acetate plus gluconate totalling 50 mEq/l. Twenty patients with normal acid-base status undergoing elective cardiac surgery were randomised 1:1 to a 2 litre prime of either bicarbonate-balanced fluid or Plasma-Lyte 148. With the trial fluid, metabolic acid-base status was normal following bypass initiation (standard base excess 0.1 (1.3) mEq/l, mean, SD), whereas Plasma-Lyte 148 produced a slight metabolic acidosis (standard base excess -2.2 (2.1) mEq/l). Estimated group difference after baseline adjustment was 3.6 mEq/l (95% confidence interval 2.1 to 5.1 mEq/l, P=0.0001). By late bypass, mean standard base excess in both groups was normal (0.8 (2.2) mEq/l vs. -0.8 (1.3) mEq/l, P=0.5). Strong ion gap values were unaltered with the trial fluid, but with Plasma-Lyte 148 increased significantly on bypass initiation (15.2 (2.5) mEq/l vs. 2.5 (1.5) mEq/l, P < 0.0001), remaining elevated in late bypass (8.4 (3.4) mEq/l vs. 5.8 (2.4) mEq/l, P < 0.05). We conclude that a bicarbonate-based crystalloid with a strong ion difference of 24 mEq/l is balanced for cardiopulmonary bypass in patients with normal acid-base status, whereas Plasma-Lyte 148 triggers a surge of unmeasured anions, persisting throughout bypass. These are likely to be gluconate and/or acetate. Whether surges of exogenous anions during bypass can be harmful requires further study.

Effect of an acute necrotic bacterial gill infection and feed deprivation on the metabolic rate of Atlantic salmon Salmo salar

In this study, experiments were conducted to examine the effect of an acute necrotic bacterial gill infection on the metabolic rate (M(O2)) of Atlantic salmon Salmo salar. Fed and unfed Atlantic salmon smolts were exposed to a high concentration (5 x 10(12) CFU ml(-1)) of the bacteria Tenacibaculum maritimum, their routine and maximum metabolic rates (M(O2rout) and M(O2max), respectively) were measured, and relative metabolic scope determined. A significant decrease in metabolic scope was found for both fed and unfed infected groups. Fed infected fish had a mean +/- standard error of the mean (SEM) decrease of 2.21 +/- 0.97 microM O2 g(-1) h(-1), whilst unfed fish a mean +/- SEM decrease of 3.16 +/- 1.29 microM O2 g(-1) h(-1). The decrease in metabolic scope was a result of significantly increased M(O2rout) of both fed and unfed infected salmon. Fed infected fish had a mean +/- SEM increase in M(O2rout) of 1.86 +/- 0.66 microM O2 g(-1) h(-1), whilst unfed infected fish had a mean +/- SEM increase of 2.16 +/- 0.72 microM O2 g(-1) h(-1). Interestingly, all groups maintained M(O2max) regardless of infection status. Increases in M(O2rout) corresponded to a significant increase in blood plasma osmolality. A decrease in metabolic scope has implications for how individuals allocate energy; fish with smaller metabolic scope will have less energy to allocate to functions such as growth, reproduction and immune response, which may adversely affect the efficiency of fish growth.

Recurrent non-specific low-back pain in adolescents: the role of exercise

This study evaluated the efficacy of an exercise programme as an intervention for recurrent non-specific low-back pain (NLSBP) in adolescents. A randomized controlled trial was conducted with an experimental group (n = 27, age 14.6 years) who participated in an 8-week exercise programme and a matched control group (n = 27, age 14.6 years) who continued normal daily activities. All participants suffered from recurrent NSLBP. Pre and post intervention measures of NSLBP status (pain severity and consequences) and daily inactivity (time spent sitting, PC time, TV time) were reported in one week diaries. Two-way mixed ANOVA (independent variables: pre/post and experimental/control) was conducted for each dependent variable, significance was set at P < 0.05. Significant interaction effects were identified for the severity of pain, number of occasions missing sport due to NSLBP and amount of sport participated in. In each case the experimental group benefited from the exercise programme. In contrast, no significant interaction effects were observed for physical inactivity, both groups spent a similar amount of time sitting, watching TV and using a PC pre- and post- intervention. It was concluded that an exercise programme acted as an effective short-term treatment strategy for NSLBP in adolescents. Further evaluation is required to assess the long-term effectiveness.

The effect of caffeine ingestion on 8 km run performance in a field setting

The aim of this study was to assess the effect of caffeine ingestion on 8 km run performance using an ecologically valid test protocol. A randomized double-blind crossover study was conducted involving eight male distance runners. The participants ran an 8 km race 1 h after ingesting a placebo capsule, a caffeine capsule (3 mg x kg(-1) body mass) or no supplement. Heart rate was recorded at 5 s intervals throughout the race. Blood lactate concentration and ratings of perceived exertion were recorded after exercise. A repeated-measures analysis of variance (ANOVA) identified a significant treatment effect for 8 km performance time (P < 0.05); caffeine resulted in a mean improvement of 23.8 s (95% confidence interval [CI] = 13.1 to 34.5 s) in 8 km performance time (1.2% improvement, 95% CI = 0.7 to 1.8%). In addition, a two-way (time x condition) repeated-measures ANOVA identified a significantly higher blood lactate concentration 3 min after exercise during the caffeine trial (P < 0.05). We conclude that ingestion of 3 mg . kg(-1) body mass of caffeine can improve absolute 8 km run performance in an ecologically valid race setting.

Removal of catheter at midnight versus early morning: the patients' perspective

BACKGROUND

With an increasing role of the patient as a partner in making a combined decision in care plan goals, it is important to identify the patient's perspective of the experience of removal of catheter (ROC).

METHODS

A non-consecutive prospective randomized study was performed in 84 patients who underwent a transurethral resection of the prostate to determine the impact of midnight versus early-morning ROC on sleep deprivation, over all discomfort to the patient.

RESULTS

There was no difference in the patient experience in both groups. We found a reduced frequency during the first 6 h of ROC at midnight. However, there was an increased incidence of sleep disturbances in this group. This may in part be due to an anxiety of urge incontinence and may be allayed by appropriate counselling. There was no delay in discharge of the patients in both groups.

CONCLUSION

The patients must, therefore, be given the choice of ROC either at midnight or early morning, as the advantages of a reduced frequency must be correlated with an increased incidence of sleep disturbances.

Histological evidence for the role of mechanical stress in modulating thermal denaturation of collagen

The hyperthermia and thermal denaturation literatures reveal a time-temperature equivalency when heating cells or connective tissues: thermal damage increases with increasing temperature (for the same duration) and increases with increasing duration (for the same temperature). Recent findings conversely suggest that increasing the mechanical loading on a tissue during heating decreases the thermal damage (for a given temperature and duration of heating). Surprisingly, however, there are few histological correlates of such damage. In this paper, we show that progressive light microscopic changes - swelling of collagen bands, thickening of collagen-rich layers, hyalinization, and loss of birefringence approximately - correlate very well with both increased heating times and decreased mechanical loading. Increased mechanical stress is thus thermally protective and should be considered in the design of clinical procedures that use heating to treat diseases or injuries.

Campylobacter jejuni gene expression in the chick cecum: evidence for adaptation to a low-oxygen environment

Transcriptional profiling of Campylobacter jejuni during colonization of the chick cecum identified 59 genes that were differentially expressed in vivo compared with the genes in vitro. The data suggest that C. jejuni regulates electron transport and central metabolic pathways to alter its physiological state during establishment in the chick cecum.

A school-based survey of recurrent non-specific low-back pain prevalence and consequences in children

The aim of this investigation was to provide evidence of the prevalence and consequences of recurrent low-back pain in children from Northwest England. A cross-sectional survey was conducted involving a standardized questionnaire with established reliability and validity. A cross-sectional sample of 500 boys (n = 249) and girls (n = 251) aged between 10 and 16 years participated in the study. Average lifetime prevalence of low-back pain was 40.2% [95% confidence interval (CI) = 38.7-41.6]. Most cases of low-back pain were acute episodes that did not lead to disabling consequences. In contrast, 13.1% (95% CI = 12.5-13.7) experienced recurrent low-back pain that led to disabling consequences; 23.1% visited a medical practitioner, 30.8% experienced loss of physical activity/sports and 26.2% had been absent from school because of low-back pain. Recurrent low-back pain was particularly evident during late adolescence where one in five children were cases. The health education implications of low-back pain in children are discussed. It was concluded that low-back pain is a common complaint during childhood, although most cases are acute episodes that represent little health consequence. In contrast, some children experience recurrent low-back pain that can lead to disabling consequences. Future research should focus on recurrent low-back pain cases since they often led to disabling consequences.

AVM modelling by multi-branching tube flow: large flow rates and dual solutions

Cerebral arteriovenous malformations (AVMs) present a common yet complex clinical challenge, through 'steal' phenomena, haemorrhage risks and epilepsy effects, aspects which are little understood even for individual lesions. The main difficulty lies in understanding the detailed haemodynamics of AVMs and especially the enhanced through-flow associated with steal. Mathematically, as a basic step, the paper investigates a nonlinear inviscid model for the planar incompressible flow of fluid through a branched geometry consisting of a single feeding mother tube which splits into two or more non-aligned daughter tubes. Recurrence relations between the unknown flow profiles in the daughter tubes and the incoming rotational flow profile in the mother tube are derived, analysed, and solved in detail in order to find the total flow rate. The results show greatly enhanced through-flow arising, for a fixed value of the total downstream flow area, either from non-unique solutions to the problem or more particularly from an increase in the number of daughter tubes, or from both, depending on the distribution of pressure differences applied across the branching region and the total downstream flow area. Extensions of the basic flow model are noted, along with comparisons with recent direct numerical simulations and discussion of possible repercussions in the context of treatment and clinical observations of enhanced through-flows in AVMs.

Specific evaluation of the function of force couples relevant for stabilization of the glenohumeral joint

Two clinical evaluation procedures for assessment of dynamic stability of the glenohumeral joint are presented in this paper, together with the biomedical evidence on which they are based. They are the Dynamic Rotary Stability Test (DRST) and the Dynamic Relocation Test (DRT). The purpose of the tests is presented and the technique required to perform the tests are described in detail.

Dynamic evaluation and early management of altered motor control around the shoulder complex

Altered dynamic control appears to be a significant contributing factor to shoulder dysfunction. The shoulder relies primarily on the rotator cuff for dynamic stability through mid-range. Hence, any impairment in the dynamic stabilizing system is likely to have profound effects on the shoulder complex. The rotator cuff appears to function as a deep stabilizer, similar to the transversus abdominus and vastus medialis obliquus, with some evidence of disruption to its stabilizing function in the presence of pain. Similarly, serratus anterior appears to function as a dynamic stabilizer, also demonstrating altered function in painful shoulders. Examination of dynamic control begins with a detailed examination of posture, evaluation of natural movement patterns and functional movements and assessment of the specific force couples relevant to shoulder function. One useful strategy in management of altered motor control related to these force couples is that of training isolated contraction of the rotator cuff prior to introduction of loaded activity, together with facilitation and training of appropriate scapular muscle force couples--serratus anterior and trapezius, in relation to arm elevation.

Contribution of proton-translocating proteins to the virulence of Salmonella enterica serovars Typhimurium, Gallinarum, and Dublin in chickens and mice

We investigated the attenuating effects of a range of respiratory chain mutations in three Salmonella serovars which might be used in the development of live vaccines. We tested mutations in nuoG, cydA, cyoA, atpB, and atpH in three serovars of Salmonella enterica: Typhimurium, Dublin, and Gallinarum. All three serovars were assessed for attenuation in their relevant virulence assays of typhoid-like infections. Serovar Typhimurium was assessed in 1-day-old chickens and the mouse. Serovar Gallinarum 9 was assessed in 3-week-old chickens, and serovar Dublin was assessed in 6-week-old mice. Our data show variation in attenuation for the nuoG, cydA, and cyoA mutations within the different serovar-host combinations. However, mutations in atpB and atpH were highly attenuating for all three serovars in the various virulence assays. Further investigation of the mutations in the atp operon showed that the bacteria were less invasive in vivo, showing reduced in vitro survival within phagocytic cells and reduced acid tolerance. We present data showing that this reduced acid tolerance is due to an inability to adapt to conditions rather than a general sensitivity to reduced pH. The data support the targeting of respiratory components for the production of live vaccines and suggest that mutations in the atp operon provide suitable candidates for broad-spectrum attenuation of a range of Salmonella serovars.

Measurement error associated with spinal mobility measures in children with and without low-back pain

AIM

Evidence of the reliability of measurements in children is scarce, particularly in children with low-back pain. The aim of this investigation was to evaluate the measurement error associated with repeated measures of spinal mobility measures in children with and without low-back pain by establishing 95% limits of agreement.

METHODS

A repeated measures study was performed involving 119 children aged 11-16 y. Of this sample 30 subjects reported recurrent low-back pain and were classified as symptomatic, the remaining 89 subjects were asymptomatic. Standardized measures were taken, including the sit-and-reach test, hip range of motion (Leighton flexometer), lumbar flexibility (modified Schöber test) and lateral flexion of the spine. The same experimenter performed all testing, with 1 wk between the repeated measures.

RESULTS

Correlation coefficients suggested that all measures exhibited good reliability in both the symptomatic (r = 0.80-0.95) and asymptomatic groups (r = 0.88-0.99). In contrast, the limits of agreement showed that all measures exhibited random error. The magnitude of random error was typically greater in the symptomatic subjects, suggesting that low-back pain may influence the reliability of typical measures used in this population.

CONCLUSION

The magnitude of error must be interpreted in relation to analytical goals and the expected magnitude of change. In the authors' opinion the error presented appears acceptable for the serial monitoring of patients, although this will depend on the differences in mobility typically found.

An overview of the biology of the wharf borer beetle (Nacerdes melanura L., Oedemeridae) a pest of wood in marine structures

The UK distribution of N. melanura is reported, based on records from museum collections, government laboratories and a field survey of wooden marine structures and driftwood along the English and Welsh coastlines. The global distribution is also reported, based on a questionnaire survey. The life cycle of the wharf borer under different environmental conditions is described and the environmental conditions over the adult emergence period presented. The cellulase complex, xylanase and a range of dissacharases were present in the larval digestive tract when tunnelling archaeological oak.

Comparison of two assay methods for activities of uroporphyrinogen decarboxylase and coproporphyrinogen oxidase

Uroporphyrinogen decarboxylase (UROD) and coproporphyrinogen oxidase (copro'gen oxidase) are two of the least well understood enzymes in the heme biosynthetic pathway. In the fifth step of the pathway, UROD converts uroporphyrinogen III to coproporphyrinogen III by the decarboxylation of the four acetic acid side chains. Copro'gen oxidase then converts coproporphyrinogen III to protoporphyrinogen IX via two sequential oxidative decarboxylations. Studies of these two enzymes are important to increase our understanding of their mechanisms. Assay comparisons of UROD and copro'gen oxidase from chicken blood hemolysates (CBH), using a newly developed micro-assay, showed that the specific activity of both enzymes is increased in the micro-assay relative to the large-scale assay. The micro-assay has distinct advantages in terms of cost, labor intensity, amount of enzyme required, and sensitivity.

Juvenile hyperthyroidism in a cat

An 8-month-old, male domestic shorthaired cat presented for chronic weight loss, intermittent dyspnea, chronic diarrhea, hyperactivity, and weakness. The cat had a palpable thyroid nodule and increased serum total thyroxine and 3,5,3' triiodothyronine levels. The cat was diagnosed with hyperthyroidism, and a unilateral thyroidectomy was performed followed by radioactive iodine at a later date. The clinical signs resolved following radioactive iodine, and the cat subsequently developed clinical hypothyroidism.

Kinetic studies of novel di- and tri-propionate substrates for the chicken red blood cell enzyme coproporphyrinogen oxidase

Coproporphyrinogen oxidase is an important enzyme in heme biosynthesis and catalyses the sequential oxidative decarboxylation of propionates on the A and B rings of the porphyrinogen ring. The effects of substituents on the C and D rings have not been systematically evaluated for their effects on the kinetic constants, K(m) and V(max). A series of synthetic porphyrinogens have been tested for their ability to affect these kinetic constants for the chicken enzyme. The enzyme exhibited the largest V(max) when incubated with the authentic substrate and was clearly able to distinguish between various substituents on the C and D rings of the macrocycle. When co-incubated with substrate, the authentic product, protoporphyrinogen-IX, appears to inhibit coproporphyrinogen oxidase and this may have an important role in the regulation of this enzyme. Thus the model for the active site of this enzyme should be modified to take these factors into account.

Engineering of complex polyketide biosynthesis--insights from sequencing of the monensin biosynthetic gene cluster

The biosynthesis of complex reduced polyketides is catalysed in actinomycetes by large multifunctional enzymes, the modular Type I polyketide synthases (PKSs). Most of our current knowledge of such systems stems from the study of a restricted number of macrolide-synthesising enzymes. The sequencing of the genes for the biosynthesis of monensin A, a typical polyether ionophore polyketide, provided the first genetic evidence for the mechanism of oxidative cyclisation through which polyethers such as monensin are formed from the uncyclised products of the PKS. Two intriguing genes associated with the monensin PKS cluster code for proteins, which show strong homology with enzymes that trigger double bond migrations in steroid biosynthesis by generation of an extended enolate of an unsaturated ketone residue. A similar mechanism operating at the stage of an enoyl ester intermediate during chain extension on a PKS could allow isomerisation of an E double bond to the Z isomer. This process, together with epoxidations and cyclisations, form the basis of a revised proposal for monensin formation. The monensin PKS has also provided fresh insight into general features of catalysis by modular PKSs, in particular into the mechanism of chain initiation.

Neurofibromatosis involving the urinary bladder

We present two interesting cases of a 24-year-old man and a 14-year-old boy, uncle and nephew, with lower urinary tract symptoms, café au lait patches and subcutaneous nodules. Ultrasonography and computed tomography scans showed a large, irregular lobulated soft tissue mass between the bladder and sacrum. Cystoscopy, laparotomy and biopsies revealed neurofibromatosis involving the urinary bladder. No enlargement of the tumor or upper urinary tract obstruction has occurred during the long-term follow up. We recommend meticulous follow up of patients with giant intrapelvic neurofibromatosis.

Indicators nurses employ in deciding to test for hyperbilirubinemia

OBJECTIVE

To identify the indicators nurses employ in deciding to test healthy full-term newborns for total serum bilirubin in the absence of a written protocol.

DESIGN

Secondary analysis of data available on 130 mother-newborn pairs and informal interviews of 30 postpartum unit nurses.

SETTING

Two university teaching hospitals.

PARTICIPANTS

All tested newborns and a 33% random sample of remaining newborns from a control group data set created during a previous study and a convenience sample of postpartum nurses from all shifts.

MEASUREMENT

Outcome data were obtained from a review of records. Background data were obtained from a review of records and questionnaires. Nurse data were obtained through a modified form of participant observation.

RESULTS

Ninety-one percent of newborns tested for bilirubin were tested unnecessarily. In logistic regression analyses, variables predictive of nurse-driven total serum bilirubin testing were presence of jaundice, odds ratio (OR) = 31.95 (95% confidence interval, 6.71, 152.03), and feeding frequency, OR = 0.28 (0.11, 0.72). Identifying both presence and location of jaundice simultaneously did not significantly predict testing, OR = 1.82 (0.66, 5.04). Fifty-three percent of nurses who were interviewed identified both the presence of jaundice and feeding as indicators to consider for testing.

CONCLUSION

Newborns are overtested for bilirubin. Indicators used by nurses in deciding to test a healthy newborn for total serum bilirubin are the presence of jaundice and feeding frequency. Nurses who assess feeding frequency are less likely to order bilirubin testing.

Quality of life assessment in patients undergoing endovascular or conventional AAA repair

PURPOSE

To compare health-related quality of life outcomes in a cohort of abdominal aortic aneurysm (AAA) patients treated concurrently with either a conventional or endoluminal intervention.

METHODS

Between December 1997 and April 1999, 51 AAA patients treated by either open or endovascular techniques were enrolled in this prospective study. Conventional therapy was performed in 26 patients (19 men; mean age 70.4 +/- 6.0 years) with anatomical features unsuitable for the endovascular approach. Twenty-five patients (23 men; mean age 70.7 +/- 7.2 years) underwent endoluminal AAA exclusion using either the Ancure or bifurcated Enduring stent-grafts. The Medical Outcomes Study Short-Form 36-item health survey was administered preoperatively and at 1, 4, 8, and > or = 52 weeks after discharge.

RESULTS

At 1 week, both groups showed significant reductions (p < 0.001) in mean scores compared to baseline in 4 dimensions (physical function, social function, role-physical, and vitality), but the decline was more pronounced in patients having open repair. Endoluminal patients returned to their baseline scores by the 4th postoperative week, whereas complete recovery to baseline in the conventional patients was delayed to the 8th week.

CONCLUSIONS

Patients treated endoluminally exhibit better physical and functional scores as early as 1 week after discharge; they also return to baseline status significantly earlier than the conventional group. These findings document the perceived advantage of endovascular therapy over conventional AAA treatment.

Salmonella enterica serovar Gallinarum requires the Salmonella pathogenicity island 2 type III secretion system but not the Salmonella pathogenicity island 1 type III secretion system for virulence in chickens

Salmonella enterica serovar Gallinarum is a host-specific serotype that causes the severe systemic disease fowl typhoid in domestic poultry and a narrow range of other avian species but rarely causes disease in mammalian hosts. Specificity of the disease is primarily at the level of the reticuloendothelial system, but few virulence factors have been described other than the requirement for an 85-kb virulence plasmid. In this work, by making functional mutations in the type III secretion systems (TTSS) encoded by Salmonella pathogenicity island 1 (SPI-1) and SPI-2, we investigated the role of these pathogenicity islands in interactions between Salmonella serovar Gallinarum and avian cells in vitro and the role of these pathogenicity islands in virulence in chickens. The SPI-1 mutant showed decreased invasiveness into avian cells in vitro but was unaffected in its ability to persist within chicken macrophages. In contrast the SPI-2 mutant was fully invasive in nonphagocytic cells but failed to persist in macrophages. In chicken infections the SPI-2 mutant was attenuated while the SPI-1 mutant showed full virulence. In oral infections the SPI-2 mutant was not observed in the spleen or liver, and following intravenous inoculation it was cleared rapidly from these sites. SPI-2 function is required by Salmonella serovar Gallinarum for virulence, primarily through promoting survival within macrophages allowing multiplication within the reticuloendothelial system, but this does not preclude the involvement of SPI-2 in uptake from the gut to the spleen and liver. SPI-1 appears to have little effect on virulence and survival of Salmonella serovar Gallinarum in the host.

Normal and Abnormal Heme Biosynthesis. 3.1Synthesis and Metabolism of Tripropionate Analogues of Coproporphyrinogen-III: Novel Probes for the Active Site of Coproporphyrinogen Oxidase

Coproporphyrinogen oxidase (copro'gen oxidase) catalyses the oxidative decarboxylation of two propionate side chains on coproporphyrinogen-III to produce protoporphyrinogen-IX. This process is very poorly understood at a molecular level, and copro'gen oxidase remains one of the least well-characterized enzymes in the heme biosynthetic pathway. To provide a rigorous test for a proposed model for substrate recognition and binding by this enzyme, two tripropionate analogues of copro'gen-III were prepared where an ethyl group replaced one of the usual propionate residues on positions 13 or 17. Although the required substrate probes are porphyrinogens (hexahydroporphyrins), the corresponding porphyrin methyl esters were initially synthesized via tripyrrene and a,c-biladiene intermediates. These were hydrolyzed and reduced with 3% sodium-amalgam to give the unstable porphyrinogens needed for the biochemical investigations. The modified structure with a 13-ethyl moiety was metabolized by avian preparations of copro'gen oxidase to give a monovinylic product, but the isomeric 17-ethylporphyrinogen afforded a divinylic product, albeit with poorer overall conversion. These results strongly support the proposed model for substrate binding at the active site of copro'gen oxidase.

Solute-binding protein-dependent ABC transporters are responsible for solute efflux in addition to solute uptake

The ATP-binding cassette (ABC) transporter superfamily is one of the most widespread of all gene families and currently has in excess of 1100 members in organisms ranging from the Archaea to manQ1. The movement of the diverse solutes of ABC transporters has been accepted as being strictly unidirectional, with recent models indicating that they are irreversible. However, contrary to this paradigm, we show that three solute-binding protein-dependent (SBP) ABC transporters of amino acids, i.e. the general amino acid permease (Aap) and the branched-chain amino acid permease (Bra) of Rhizobium leguminosarum and the histidine permease (His) of Salmonella typhimurium, are bidirectional, being responsible for efflux in addition to the uptake of solutes. The net solute movement measured for an ABC transporter depends on the rates of uptake and efflux, which are independent; a plateau is reached when both are saturated. SBP ABC transporters promote active uptake because, although the Vmax values for uptake and efflux are not significantly different, there is a 103-104 higher affinity for uptake of solute compared with efflux. Therefore, the SBP ABC transporters are able to support a substantial concentration gradient and provide a net uptake of solutes into bacterial cells.

Variation in shoulder position sense at mid and extreme range of motion

OBJECTIVE

To determine the effect of different joint positions on position sense of asymptomatic shoulders.

DESIGN

Repeated-measures design.

SETTING

Laboratory in an educational institution.

PARTICIPANTS

Thirty-four asymptomatic, right-handed men.

INTERVENTIONS

The ability of subjects to replicate 3 criterion positions was examined on subjects' right shoulders by using an isokinetic dynamometer. Three criterion positions were the 50th, 75th, and 90th percentiles of each individual's total passive shoulder rotation range measured from the full internal rotation position.

MAIN OUTCOME MEASURE

Repositioning accuracy, indicating the difference in degrees between the criterion and matching positions.

RESULTS

All subjects were able to reproduce the criterion position near the end of external rotation range more accurately and consistently than in the middle range of motion (ROM).

CONCLUSIONS

Position sense acuity at the shoulder complex varied across the ROM and may be enhanced near the end of rotation range where there is more tension on the restraints to movement. Therefore, an individual's ROM should be factored into any attempt to assess or rehabilitate shoulder proprioception.

Mortality in rheumatoid arthritis: relationship to single and composite measures of disease activity

BACKGROUND

Rheumatoid arthritis (RA) is a heterogeneous disease characterized by a variable course of remissions and relapses. Single measures of disease activity at only one point in time may not reflect the overall control of disease activity.

OBJECTIVE

The aim was to determine (i) the predictive value of 20 baseline demographic and disease variables on mortality, and (ii) the relationship between serial measures of the Stoke index (SI; a validated index of disease activity in RA) and mortality in RA.

METHODS

Mortality in 309 RA patients followed up for a median of 14 yr was analysed retrospectively. The standardized mortality ratio (SMR) was calculated for all causes of death. The predictive values of baseline and time-integrated variables were assessed using multivariate Cox proportional hazards regression analysis.

RESULTS

The SMR was 1.65. At baseline, only nodules, erosions, RA latex titre, white cell count and globulin level were predictive of mortality after correction for age, sex and disease duration. Using a stepwise Cox proportional hazards regression model, the most powerful predictors of mortality were age, nodules and RA latex titre. Individual measures of disease activity and the SI at baseline were not predictive of mortality. However, the mean level of the SI over 12 months was related to mortality (P=0.039).

CONCLUSIONS

At baseline, the demographic and disease variables most significantly related to mortality in RA are age, nodules and RA latex titre. Individual measures of disease activity at a single point in time are poor predictors of mortality in RA. However, measurement of the mean level of disease activity over time using the composite SI has a significant relationship with mortality. A high level of sustained inflammation appears to be an important predictor of premature death.

Vaginal metastases from renal cell carcinoma: report of four cases and review of the literature

Between 1987 and 1997, four patients presented with gynecologic symptoms that on evaluation revealed vaginal metastases from renal cell carcinoma. Two patients had isolated metastases and were treated with nephrectomy, local excision of the vaginal lesion and post-operative radiotherapy. Both are alive without evidence of disease at 24 and 30 months, respectively. The other two patients had widespread disease and died within a year of diagnosis. Seventy-one cases of vaginal metastases from renal cell carcinoma have been reported in the literature.

Improved survival after endoluminal repair with second-generation prostheses compared with open repair in the treatment of abdominal aortic aneurysms: a 5-year concurrent comparison using life table method

PURPOSE

The aim of this study was to compare the outcome of consecutive patients with abdominal aortic aneurysm (AAA) treated concurrently by means of open repair (OR) and endoluminal repair (ER) with second-generation prostheses by the same surgeons during a defined interval.

METHODS

Between May 1995 and December 1998 second-generation (low profile, fully supported, modular) endoprostheses were implanted in 148 patients. These patients, together with 135 patients treated concurrently with OR during the same period, comprised the study group of 283 patients. Patient selection was based on aneurysm morphology. Those patients who were anatomically suitable for ER were treated with this method. The ER and OR groups were similar with regard to age, sex, and size of AAA. The ER group contained high-risk patients considered unfit for OR (n = 46), and the OR group contained high-risk patients who were anatomically unsuitable for ER (n = 19). Outcome criteria in both groups were survival and successful aneurysm repair. Success in the ER group was defined as exclusion of the aneurysm sac and stability or reduction in AAA maximum transverse diameter. Persistent endoleaks were classified as failures, regardless of whether they were subsequently corrected with secondary endovascular intervention. Data were analyzed with the life table method. The minimum period of follow-up for all patients was 18 months.

RESULTS

The perioperative mortality rate was 5.9% in the OR group and 2.7% in the ER group (not significant). There was a statistically significant difference between the survival curves of the two groups in favor of the ER group when analyzed with the log-rank test (P =.004). The Kaplan-Meier curve for graft failure for the ER group revealed a 3-year graft success probability of 82%. Survival probability with successful repair in the OR group at 3 years was 85%.

CONCLUSIONS

A concurrent comparison of ER with second-generation prostheses versus OR demonstrated a significant difference in survival in favor of the ER group. The probability of survival with successful repair at 3 years was similar in both groups.

Nitric oxide is a downstream mediator of agrin-induced acetylcholine receptor aggregation

The synaptic basal lamina protein, agrin, is required for the formation of the neuromuscular junction. Agrin signals through a muscle-specific receptor tyrosine kinase (MuSK) initiating a cascade of events that lead to the aggregation of acetylcholine receptors (AChR) at the postsynaptic site. Another important synaptic signalling molecule is nitric oxide (NO), which is produced by the enzyme, nitric oxide synthase (NOS). We investigated the interaction between the agrin signalling cascade and the NO signalling cascade by treating cultured myotubes with agrin, NOS inhibitors, and NO donors. NOS inhibitors prevented agrin induced AChR aggregation and phosphorylation of the AChR beta subunit. Furthermore, NO donors induced AChR aggregation in the absence of agrin, as well as phosphorylation of the AChR beta subunit. These results demonstrate a role for NO as a downstream mediator of agrin induced AChR aggregation and AChR beta subunit phosphorylation at the neuromuscular junction.