Factors associated with hepatitis C and HIV testing uptake among men who inject image and performance enhancing drugs

INTRODUCTION AND AIMS

Historically, people who inject image and performance enhancing drugs (IPED) were not perceived as being at high risk of HIV or hepatitis C virus (HCV) infection. However, recent studies indicate HCV and HIV prevalences are elevated, with many HCV infections undiagnosed.

DESIGN AND METHODS

Men who inject IPEDs recruited from community settings and specialist services, including needle-syringe programs, across UK during 2016 self-completed a questionnaire. Multivariate analyses examined factors associated with HCV/HIV testing.

RESULTS

The participants' (n=562; 24% service recruited) median age was 31 years, 4% identified as gay or bisexual, 18% had ever been imprisoned and 6% had ever injected a psychoactive drug. Those community recruited more often reported sharing drugs vials (16% vs. 8%, P=0.021) and, among those with 2+ sexual partners, poor condom use (50% vs. 36%, P=0.063), than those service recruited. Overall, one-third had ever been tested for HCV (31%) and/or HIV (34%). Testing uptake was associated with other risk factors for HCV/HIV, being recruited through services and having received metabolic tests. Participants' motivations for using IPEDs were associated with recruitment setting and HIV/HCV testing uptake.

DISCUSSION AND CONCLUSIONS

The majority were untested for HCV/HIV. HCV/HIV testing and risks were associated with recruitment through services. Previous needle and syringe program-based studies have potentially overestimated testing uptake and underestimated risk. Targeted interventions are needed, particularly for those not accessing services. The association between HCV/HIV testing uptake and receipt of metabolic tests suggests that developing a combined offer of these tests as part of health monitoring could improve uptake.

The cost-effectiveness of an HCV outreach intervention for at-risk populations in London, UK

Background

HCV disproportionately affects marginalized communities such as homeless populations and people who inject drugs (PWID), posing a challenge to traditional health services. The HepFriend initiative in London is a model of care utilizing HCV outreach screening and peer support to link vulnerable individuals to HCV treatment in secondary care.

Objectives

To assess the cost-effectiveness of the HepFriend initiative from a healthcare provider perspective, compared with standard-of-care pathways (consisting of testing in primary care and other static locations, including drug treatment centres, and linkage to secondary care).

Methods

Cost-effectiveness analysis using a dynamic HCV transmission and disease progression model among PWID and those who have ceased injecting, including housing status and drug treatment service contact. The model was parameterized using London-specific surveillance and survey data, and primary intervention cost and effectiveness data (September 2015 to June 2018). Out of 461 individuals screened, 197 were identified as HCV RNA positive, 180 attended secondary care and 89 have commenced treatment to date. The incremental cost-effectiveness ratio (ICER) was determined using a 50 year time horizon.

Results

For a willingness-to-pay threshold of £20000 per QALY gained, the HepFriend initiative is cost-effective, with a mean ICER of £9408/QALY, and would become cost saving at 27% (£10525 per treatment) of the current drug list price. Results are robust to variations in intervention costs and model assumptions, and if treatment rates are doubled the intervention becomes more cost-effective (£8853/QALY).

Conclusions

New models of care that undertake active case-finding with enhanced peer support to improve testing and treatment uptake amongst marginalized and vulnerable groups could be highly cost-effective and possibly cost saving.

Evaluating the population impact of hepatitis C direct acting antiviral treatment as prevention for people who inject drugs (EPIToPe) - a natural experiment (protocol)

INTRODUCTION

Hepatitis C virus (HCV) is the second largest contributor to liver disease in the UK, with injecting drug use as the main risk factor among the estimated 200 000 people currently infected. Despite effective prevention interventions, chronic HCV prevalence remains around 40% among people who inject drugs (PWID). New direct-acting antiviral (DAA) HCV therapies combine high cure rates (>90%) and short treatment duration (8 to 12 weeks). Theoretical mathematical modelling evidence suggests HCV treatment scale-up can prevent transmission and substantially reduce HCV prevalence/incidence among PWID. Our primary aim is to generate empirical evidence on the effectiveness of HCV 'Treatment as Prevention' (TasP) in PWID.

METHODS AND ANALYSIS

We plan to establish a natural experiment with Tayside, Scotland, as a single intervention site where HCV care pathways are being expanded (including specialist drug treatment clinics, needle and syringe programmes (NSPs), pharmacies and prison) and HCV treatment for PWID is being rapidly scaled-up. Other sites in Scotland and England will act as potential controls. Over 2 years from 2017/2018, at least 500 PWID will be treated in Tayside, which simulation studies project will reduce chronic HCV prevalence among PWID by 62% (from 26% to 10%) and HCV incidence will fall by approximately 2/3 (from 4.2 per 100 person-years (p100py) to 1.4 p100py). Treatment response and re-infection rates will be monitored. We will conduct focus groups and interviews with service providers and patients that accept and decline treatment to identify barriers and facilitators in implementing TasP. We will conduct longitudinal interviews with up to 40 PWID to assess whether successful HCV treatment alters their perspectives on and engagement with drug treatment and recovery. Trained peer researchers will be involved in data collection and dissemination. The primary outcome - chronic HCV prevalence in PWID - is measured using information from the Needle Exchange Surveillance Initiative survey in Scotland and the Unlinked Anonymous Monitoring Programme in England, conducted at least four times before and three times during and after the intervention. We will adapt Bayesian synthetic control methods (specifically the Causal Impact Method) to generate the cumulative impact of the intervention on chronic HCV prevalence and incidence. We will use a dynamic HCV transmission and economic model to evaluate the cost-effectiveness of the HCV TasP intervention, and to estimate the contribution of the scale-up in HCV treatment to observe changes in HCV prevalence. Through the qualitative data we will systematically explore key mechanisms of TasP real world implementation from provider and patient perspectives to develop a manual for scaling up HCV treatment in other settings. We will compare qualitative accounts of drug treatment and recovery with a 'virtual cohort' of PWID linking information on HCV treatment with Scottish Drug treatment databases to test whether DAA treatment improves drug treatment outcomes.

ETHICS AND DISSEMINATION

Extending HCV community care pathways is covered by ethics (ERADICATE C, ISRCTN27564683, Super DOT C Trial clinicaltrials.gov: NCT02706223). Ethical approval for extra data collection from patients including health utilities and qualitative interviews has been granted (REC ref: 18/ES/0128) and ISCRCTN registration has been completed (ISRCTN72038467). Our findings will have direct National Health Service and patient relevance; informing prioritisation given to early HCV treatment for PWID. We will present findings to practitioners and policymakers, and support design of an evaluation of HCV TasP in England.

Secondary distribution of injecting equipment obtained from needle and syringe programmes by people injecting image and performance enhancing drugs: England and Wales, 2012-15

BACKGROUND

People who inject image and performance enhancing drugs (IPEDs) are often the largest group using needle and syringe programmes (NSPs) in the UK. NSP providers report these clients repeatedly collecting large amounts of equipment for others. The extent of secondary distribution of injecting equipment is unknown.

METHODS

Data from national surveillance of people injecting IPEDs were used. Participants completed a questionnaire and provided a dried-blood spot sample. Data from two biennial surveys was combined; repeat participants were excluded. Self-reported data was used to explore the extent of secondary distribution.

RESULTS

Of the participants, 87% (467) reported NSP use; median age was 31 years; 98% were male. A third (34%, 157) reported collecting equipment for others. Of those collecting for others, 154 reported how many people they had collected for: 55% had collected for one person, 27% for 2-9 people, 5% for 10-19 and 13% for 20 or more (no difference by psychoactive drug use). Those vaccinated for hepatitis B were more likely (22% [15/68] vs 6% [5/86], p = 0.003), and those reporting redness/swelling at an injection site were less likely to collect equipment for at least 20 others (8% [8/106] vs 25% [12/48], p = 0.003). Overall, 154 people collected equipment for 639-1569 people injecting IPEDs.

CONCLUSIONS

Secondary distribution of injecting equipment is common among those injecting IPEDs and using NSPs. Whilst not allowing for rotational collection within groups, our analysis suggests that many of those injecting IPEDs are not in direct contact with NSPs. Innovation approaches for harm reduction interventions are needed.

Sexualised drug use in the United Kingdom (UK): A review of the literature

BACKGROUND

Sexualised drug use (SDU) refers to the use of drugs in a sexual context. This includes 'Chemsex'- the use of drugs (specifically crystal methamphetamine, GHB/GBL and mephedrone) before or during planned sexual activity to sustain, enhance, disinhibit or facilitate the experience. Here we aimed to synthesise available UK prevalence data for Chemsex, SDU and the use of Chemsex drugs in an undefined context (CDU) in men who have sex with men (MSM).

METHODS

Papers published between January 2007 and August 2017 reporting Chemsex, SDU and/or Chemsex drug use (CDU) prevalence in MSM were identified through PubMed. Citations were searched for further eligible publications. We also conducted a review of national surveillance data, extracting prevalence data for Chemsex, SDU or CDU. Synthesized data were then assessed to determine the time at which these drugs were taken, in this case just prior to or during sexual activity (event-level).

RESULTS

Our search identified 136 publications, of which 28 were included in the final data synthesis. Three of the four surveillance systems assessed provided SDU or CDU data in MSM. Few publications included event-level data for Chemsex (n = 4), with prevalence estimates ranging from 17% among MSM attending sexual health clinics (SHC) to 31% in HIV-positive MSM inpatients. Prevalence estimates for SDU (n = 7 publications) also varied considerably between 4% in MSM receiving HIV care to 41% among MSM attending SHC for HIV post-exposure prophylaxis (PEP). Eighteen publications provided data for CDU.

CONCLUSION

Prevalence estimates varied considerably due to differences in the definition used and population assessed. Standardised definitions and studies with representative national samples of MSM are required to improve our understanding of the extent of Chemsex and its associated risks. Longitudinal event-level data for SDU and Chemsex are needed to monitor impact of interventions.

Low levels of hepatitis C diagnosis and testing uptake among people who inject image and performance enhancing drugs in England and Wales, 2012-15

INTRODUCTION

People injecting image and performance enhancing drugs (IPEDs) have traditionally not been perceived as being at high risk of hepatitis C virus (HCV) infection. However, recent studies indicate the HCV antibody (anti-HCV) prevalence in this group is 10-times that in the general population. HCV testing uptake and undiagnosed infections are examined using data from a voluntary unlinked-anonymous survey.

METHOD

People injecting IPEDs across England and Wales completed a short bio-behavioural survey (2012-15). Anti-HCV status and self-reports of HCV testing were used in the analysis.

RESULTS

The participants median age was 31 years, 98% were men, 14% had also injected psychoactive drugs and the anti-HCV prevalence was 4.8% (N=564). Among those who had never injected psychoactive drugs the anti-HCV prevalence was 1.4%; among those who had recently injected psychoactive drugs (preceding 12 months) prevalence was 39% and among those who had done this previously 14% (p<0.001). Overall, 37% had been tested for HCV: among those who had recently injected psychoactive drugs 78% had been tested, as had 56% of those who had injected psychoactive drugs previously; 33% of those never injecting psychoactive drugs were tested (p<0.001). Overall, 44% of those with anti-HCV were aware of this; however, only 14% of those who had never injected psychoactive drugs were aware.

CONCLUSIONS

One-in-twenty people who inject IPEDs have anti-HCV. HCV infections among those who had never injected psychoactive drugs were mostly undiagnosed, though this group had a lower prevalence. Targeted HCV testing interventions are also needed for those injecting IPEDs.

Ongoing outbreak of invasive and non-invasive disease due to group A Streptococcus (GAS) type emm66 among homeless and people who inject drugs in England and Wales, January to December 2016

We report an outbreak of invasive and non-invasive disease due to an unusual type of Streptococcus pyogenes(group A Streptococcus, emm66) among a vulnerable, largely homeless population in southern England and Wales, detected in September 2016. Twenty-seven confirmed cases were subsequently identified between 5 January and 29 December 2016; 20 injected drugs and six reported problematic alcohol use. To date, we have ruled out drug-related vehicles of infection and identified few common risk factors.

Perceptions of pesticides exposure risks by operators, workers, residents and bystanders in Greece, Italy and the UK

The EU Directive on the sustainable use of pesticides (EU128/2009/EC) requires European Member States to develop training activities targeting occupational exposure to pesticides, and communication material aimed at residents and bystanders. Risk perceptions, knowledge and attitudes associated with passive and occupational exposure to pesticide potentially influence the extent to which different stakeholders adopt self-protective behaviour. A methodology for assessing the link between attitudes, adoption of self-protective behaviours and exposure was developed and tested. A survey was implemented in the Greece, Italy and the UK, and targeted stakeholders associated with pesticide exposure linked to orchards, greenhouse crops and arable crops respectively. The results indicated that the adoption of protective measures is low for residents and bystanders, with the exception of residents in Greece, when compared to operators and workers, who tend to follow recommended safety practices. A regression analysis was used to examine the factors affecting the probability of adopting protective measures as well the as the level of exposure in the case of operators and workers where data are available. The results indicate that the likelihood of engaging in self-protective behaviour is not significantly affected by perceptions of own health being affected by pesticides for residents and bystanders. However, operators who perceive that their heath has been negatively affected by the use of pesticides are found to be more likely to adopt self-protective behaviours. Gender and country differences, in perceptions, attitudes and self-protection are also observed. Recommendations for improved communication, in particular for vulnerable groups, are provided.

Biliary boulders

OBJECTIVE

To examine the outcome of endoscopic retrograde cholangiopancreatography (ERCP) in the management of common bile duct (CBD) stones.

DESIGN

A retrospective review of 100 consecutive ERCPs performed for CBD stones.

RESULTS

100 ERCPs were performed on 84 patients with a median cohort age of 77. Completion in this cohort, as defined by duct clearance, was achieved in 65% of cases. Completion rates fell rapidly after two ERCPs. 33% of the cohort had small stones <10 mm, and 67% had stones >10 mm. Size, but not number of stones, affected the completion rate and frequency of complications (16%). Presence of periampullary diverticulum did not affect completion or complication rates. MR cholangiopancreatography (MRCP) had a 90% sensitivity for detecting CBD stones compared with 56% for CT.

DISCUSSION AND CONCLUSIONS

ERCP remains a high-risk procedure with a significant complication rate when performed to deal with CBD stones. MRCP should be the second choice of investigation for CBD stones. This cohort had an unusually high number of larger stones at ERCP of 67% compared with other published UK cohorts of 8%, and this was reflected in the completion and complication rate.

Minocycline reduces glioma expansion and invasion by attenuating microglial MT1-MMP expression

Glioma cells release soluble factors, which induce the expression of membrane type 1 matrix metalloprotease (MT1-MMP) in tumor associated microglia and then exploit MT1-MMP mediated matrix degradation for invasion. Here, we show that minocycline blocked the increase in MT1-MMP expression and activity in cultivated microglia stimulated with glioma conditioned medium. Glioma growth within an organotypic brain slice preparation was reduced by minocycline and this reduction depended on the presence of microglia. Glioma growth in an experimental mouse model was strongly reduced by the addition of minocycline to drinking water, compared to untreated controls. Coherently, we observed in our orthotopic glioma implantation model, that MT1-MMP was abundantly expressed in glioma associated microglia in controls, but was strongly attenuated in tumors of minocycline treated animals. Overall, our study indicates that the clinically approved antibiotic minocycline is a promising new candidate for adjuvant therapy against malignant gliomas.

Ultrastructural identification of P2Y2 receptor mRNA in the rat thymus

In situ hybridisation to identify P2Y(2) receptor mRNA was performed for the first time at the ultrastructural level on the thymus of adult male rats. These studies revealed transcripts for P2Y(2) receptors in cortical T cells and endothelial cells of thymic blood vessels. These transcripts are likely to be linked with the production of functional P2Y(2) receptors in these cells. In the T cells, transcripts for the P2Y(2 )receptor were localised in the cytoplasm as well as on the smooth endoplasmic reticulum and cell membrane. Dividing T cells also expressed P2Y(2 )receptor mRNA, mostly in the cytoplasm around chromosomal material. Endothelial cells displaying labels for P2Y(2 )receptor transcripts were of cortical arteries/arterioles and capillaries and of postcapillary venules in the corticomedullary junction. P2Y(2) mRNA transcripts were localised in the cytoplasm of endothelial cells, although they did not appear to be specifically associated with subcellular organelles or structures. In postcapillary venules, T cells displaying labelling for the P2Y(2) receptor were seen migrating across the P2Y(2) receptor mRNA-positive endothelium. Our findings are discussed in terms of the relationship between thymic immune cells and the endothelium. This includes the issue of immune cell trafficking into the circulation, and the ATP-related regulatory role and involvement of P2Y(2) receptors in the rat thymus.

P2 receptors in the murine gastrointestinal tract

The actions of adenosine, adenosine 5'-triphosphate (ATP), 2-methylthio adenosine diphosphate ADP (2-MeSADP), 2-methylthio ATP (2-MeSATP), alpha,beta-methylene ATP (alpha,beta-meATP) and uridine triphosphate (UTP) on isolated segments of mouse stomach (fundus), duodenum, ileum and colon were investigated. The localization of P2Y(1), P2Y(2), P2Y(4), P2X(1) and P2X(2) receptors and neuronal nitric oxide synthase (NOS) were examined immunohistochemically, and P2Y(1) mRNA was examined with in situ hybridization. The order of potency for relaxation of longitudinal muscle of all regions was: 2-MeSADP>/=2-MeSATP>alpha,beta-meATP>ATP=UTP=adenosine. This is suggestive of P2Y(1)-mediated relaxation and perhaps a further P2Y receptor subtype sensitive to alpha,beta-meATP. As ATP and UTP are equipotent, the presence of a P2Y(2) receptor is indicated. ATP responses were inhibited by the P2Y(1)-selective antagonist MRS 2179, and suramin. P2Y(1) receptors were visualized immunohistochemically in the smooth muscle of the ileum and in a subpopulation for myenteric neurones, which also stained for NOS. P2Y(1) mRNA was localized in neurones in both myenteric and submucosal ganglia in the ileum. Taken together, these results suggest that ATP was acting on non-adrenergic, non-cholinergic inhibitory neurons, which release both nitric oxide (NO) and ATP. Reduced relaxations to 2-MeSADP by tetrodotoxin and N(omega)-nitro-L-arginine methyl ester, are consistent with this possibility. Adenosine acts via P1 receptors to relax smooth muscle of the mouse gut. Segments of mouse colon (in contrast to the stomach and small intestine) were contracted by nucleotides with the potency order: 2-MeSATP>alpha,betameATP>ATP; the contractions showed no desensitization and were antagonized by suramin and PPADS, consistent with responses mediated by P2X(2) receptors. Immunoreactivity to P2X(2) receptors was demonstrated on both longitudinal and circular muscle of the colon, but not in the other regions of the gut, except for a small subpopulation of myenteric neurones. In summary, neuronal P2Y(1) receptors appear to mediate relaxation, largely through NO in all regions of the mouse gut, and to a lesser extent by P2Y(1), P2Y(2) and a novel P2Y receptor subtype responsive to alpha,beta-meATP in smooth muscle, while P2X(2) receptors mediate contraction of colonic smooth muscle.

P2X4 and P2X6 receptors associate with VE-cadherin in human endothelial cells

We investigated the expression of P2X4 and P2X6 receptors on human umbilical vein endothelial cells (HUVECs) and found that both P2X receptor subtypes on plasma membranes are largely restricted to areas of cell-cell contact. Co-labelling experiments at the confocal and electron microscopy levels revealed that P2X4 and P2X6 receptors are strongly co-localised with the cell adhesion molecule VE-cadherin. The P2X4 and P2X6 receptors on plasma membranes at cellular junctions are rapidly (within 5 min) internalised specifically after decreasing extracellular [Ca2+]. Disruption of microfilaments, microtubules and integrin-mediated adhesion or stimulation of P2 receptors with ATP did not alter P2X4 and P2X6 receptor expression on HUVEC plasma membranes. Membraneous P2X4 and P2X6 receptors resisted extraction with Triton-X 100, whereas cytoplasmic P2X receptors were Triton-X 100 soluble. P2X4 receptors, but not P2X6 receptors, could be co-immunoprecipitated with VE-cadherin and vice versa. We conclude that P2X4 and P2X6 receptors are associated with VE-cadherin at HUVEC adherens junctions.

Expression of nucleotide P2X receptor subtypes during spermatogenesis in the adult rat testis

The expression of ATP-gated ion channels (P2X receptors) was investigated in testes of adult rats by immunohistochemistry and Western blotting with antibodies against all seven P2X receptor subtypes. Immunoreactive cells were identified and monitored during germ cell maturation. Results of immunohistochemical and Western blotting experiments showed the expression of P2X(1), P2X(2), P2X(3), P2X(5) and P2X(7) receptors, while P2X(4) and P2X(6) receptors were absent from the testis. Blood vessels displayed immunostaining for P2X(1) and P2X(2) receptors; the P2X(1) receptors were present exclusively in blood vessels. P2X(2), P2X(3) and P2X(5) receptors were found to be expressed differentially in the various germ cell types throughout the different stages of the cycle of the seminiferous epithelium; P2X(2) and P2X(3) receptors were always observed together in the same cell types and at the same stages. Sertoli cells also showed differential staining for P2X(2) and P2X(3) receptors during the cycle of the seminiferous epithelium, whereas P2X(7) receptor expression was present throughout all stages. No immunostaining for P2X receptors was detected on Leydig cells. The possible roles of purinergic signalling in the control of germ cell maturation are discussed. In particular, it is suggested that purinergic signalling may play a role in controlling the maturation of germ cell subsets of different developmental ages that exist alongside each other in the adult testis.

Characterization of house dust mite and scabies mite allergens by use of canine serum antibodies

OBJECTIVE

To identify the major allergenic proteins from the 3 main species of dust mites to which dogs react (Dermatophagoides farinae, D. pteronyssinus, and Euroglyphus maynei) and evaluate the potential cross-reactivity of dust mite allergens with antigens from the ectoparasitic mite Sarcoptes scabiei var canis.

SAMPLE POPULATION

Sera from 83 dogs with atopic dermatitis.

PROCEDURE

Sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunoblotting using serum from atopic dogs was used to identify IgE-binding proteins in extracts of the 4 mite species.

RESULTS

Sera of atopic dogs contained IgE against 23, 17, 25, and 17 allergens from D. farinae, D. pteronyssinus, E. maynei, and S. scabiei, respectively. Unlike the situation for humans, the major allergens for dogs are mostly proteins that are larger than 90 kd molecular weight. Dermatophagoides farinae and E. maynei appear to be more allergenic for dogs than is D. pteronyssinus. Some dogs with serum IgE against dust mites also had IgE against antigens of S. scabiei var canis.

CONCLUSIONS AND CLINICAL RELEVANCE

Multiple dust mite allergens induce an IgE response in dogs. These allergens are mostly greater than 90 kd molecular weight.

Development of fiber optic and electrochemical pH sensors to monitor brain tissue

This article describes fiber optic and electrochemical pH sensors that could become part of a therapeutic arsenal to quickly and aggressively treat stroke victims as well as people who have suffered brain trauma. The fiber optic sensor design was based on the immobilization of a pH-sensitive dye, seminaphthorhodamine-1 carboxylate (SNARF-1C), onto the end of a 125-microm-diameter silica optical fiber using the sol-gel method. A miniature bench-top fluorimeter system was developed for use with the optical fiber to obtain pH measurements. The electrochemical sensor was based on sputter-coated iridium oxide thin films. Linear and reproducible responses for both sensors were obtained in human blood with pH varying between 6.8 ato 8.0, which encompasses the clinically relevant range. In vivo studies were also performed and results indicated that both types of sensors tracked pH with very little drift.

Where children sit in cars: the impact of Rhode Island's new legislation

OBJECTIVES

This study evaluated the impact of Rhode Island's legislation requiring children younger than 6 years to sit in the rear of motor vehicles.

METHODS

Roadside observations were conducted in Rhode Island and Massachusetts in 1997 and 1998. Multivariate regression was used to evaluate the proportion of vehicles carrying a child in the front seat.

RESULTS

Data were collected on 3226 vehicles carrying at least 1 child. In 1998, Rhode Island vehicles were less likely to have a child in the front seat than in 1997 (odds ratio = 0.6; 95% confidence interval = 0.5, 0.7), whereas no significant changes in child passenger seating behavior occurred in Massachusetts during that period.

CONCLUSIONS

Rhode Island's legislation seems to have promoted safer child passenger seating behavior.

Rhesus rotavirus-based quadrivalent vaccine is efficacious despite age, socioeconomic conditions and seasonality in Venezuela

This report describes the results of additional analyses of the trial carried out with the rhesus rotavirus-based quadrivalent vaccine in Venezuela. In the present study, we re-examined the data from this previous rotavirus vaccine trial to assess the statistical interaction between vaccine efficacy and (i) the duration of efficacy into the second year of life, (ii) socioeconomic conditions, and (iii) rotavirus seasonality. We found that among Venezuelan children, the rotavirus vaccine confers protection against severe diarrhea during the first 2 years of life independently of socioeconomic conditions and seasonality.

Expression of P2 receptors in bone and cultured bone cells

Extracellular nucleotides acting through P2 receptors elicit a wide range of responses in many cell types. There is increasing evidence that adenosine triphosphate (ATP) may function as an important local messenger in bone and cartilage. In this study, we used immunocytochemistry, employing novel polyclonal antibodies against P2X(1-7) receptors, and in situ hybridization, using oligonucleotide probes corresponding to P2X(2,4) and P2Y(2,4) messenger RNAs (mRNAs), to localize P2 receptors on undecalcified bone sections and on cultured osteoblasts and osteoclasts. We provide the first direct evidence that the P2X(2) receptor subtype is expressed on osteoclasts, osteoblasts, and chondrocytes. We also obtained evidence for the expression of P2X(5) and P2Y(2) receptors on osteoblasts and chondrocytes, and for P2X(4) and P2X(7) receptors on osteoclasts. Our results confirm earlier reports of P2Y(2) and P2X(4) expression in human osteoclastoma and rabbit osteoclasts, respectively, and are consistent with ATP responses observed on bone cells using electrophysiological techniques. Our novel finding that P2X(2) is expressed by osteoclasts is of particular interest. P2X(2) is the only P2 receptor subtype that requires extracellular acidification to show its full sensitivity to ATP, and our recent functional studies have shown that the stimulatory action of ATP on resorption pit formation by mature osteoclasts is amplified greatly at low pH. These findings point to fundamental new mechanisms for the local modulation of bone resorption.

Lactulose-mannitol intestinal permeability test in children with diarrhea caused by rotavirus and cryptosporidium. Diarrhea Working Group, Peru

BACKGROUND

The relationship between intestinal permeability and acute secretory diarrheal syndromes caused by rotavirus and Cryptosporidium parvum in infants less than 36 months of age was studied using the lactulose-mannitol excretion assay.

METHODS

An oral solution containing 0.4 g/kg lactulose and 0.1 g/kg mannitol was administered to 15 infants with rotavirus, 7 with Cryptosporidium infection and a control group of 7 with secretory diarrhea admitted to the Oral Rehydration Unit of the National Children's Hospital in Lima, Peru. Urinary sugar excretion was measured using an enzymatic spectrophotometric method. The ratio of urinary excretion of lactulose to mannitol was used to measure intestinal mucosal permeability, with higher ratios indicative of increased intestinal permeability. Infants in all three groups were retested 20 days after the initial test.

RESULTS

The (mean +/- SE) lactulose:mannitol (L:M) excretion ratios during the acute phase (day 1) of diarrhea in infants with rotavirus or Cryptosporidium and control infants were 0.67 +/- 0.1, 0.76 +/- 0.16, and 0.26 +/- 0.04, respectively. In the convalescent phase (day 20) the ratios were 0.19 +/- 0.02, 0.28 +/- 0.05, and 0.29 +/- 0.07, respectively. Significant reductions in L:M ratios were noted in rotavirus patients between days 1 and 20 (paired t-test; P < 0.01), Cryptosporidium patients between days 1 and 20 (paired t-test; P < 0.05), and between control subjects on day 1 and rotavirus patients on day 1 and Cryptosporidium patients on day 1 (unpaired t-tests; P < 0.05 for both). There were no significant differences in control subjects between days 1 and 20, control subjects and rotavirus patients on day 20, or control subjects and Cryptosporidium patients on day 20.

CONCLUSIONS

The results indicate that increased intestinal permeability caused by rotavirus or cryptosporidium infections in Peruvian infants less than 36 months of age is a significant but reversible phenomenon. The temporal relationship observed in the current study and the contribution of such alterations in intestinal mucosal integrity to the burden of diarrheal disease and the development of malnutrition in developing countries is discussed.

P2 receptors in the thymus: expression of P2X and P2Y receptors in adult rats, an immunohistochemical and in situ hybridisation study

The expression of the seven P2X receptor subtypes and of two P2Y receptors was examined immunohistochemically and by in situ hybridisation in thymi of adult male rats. P2X4, P2Y2 and 4 receptor mRNA colocalisation studies combining in situ hybridisation and immunohistochemistry were also carried out. P2X and P2Y receptors were found on thymocytes. P2X receptors were also abundant in cells of the thymic microenvironment, involved in control of T-cell maturation in vivo. We are the first to describe the expression of P2X4 receptors on thymocytes and confirm the finding of P2X1 and P2Y2 receptors on subpopulations of lymphocytes. P2X1,2,3,4 and 5 receptors were present in blood vessels of the thymus. P2X1,2 and 4 receptors were detected in vascular smooth muscle, while P2X3 receptors appeared to be associated with endothelial cells; some small arteries were positive for P2X5, possibly labelling vascular smooth muscle or fibroblasts in the adventitia. P2X2,3,6 and 7 receptors were found on thymic epithelial cells. P2X2 and 3 receptors were abundant on medullary epithelial cells, whilst P2X6 receptors were prominent in Hassall's corpuscles. P2X2 receptors were found on subcapsular and perivascular epithelial cells. P2X2,6 and 7 receptors were detected in epithelial cells along the thymic septa. Expression of P2X receptors was also investigated by Western blotting of crude thymic tissue extracts under reducing conditions. All seven P2X receptor subtypes were found to be dimers of approximately 70 kDa and 140 kDa molecular weight. ATP-mediated apoptosis and cell proliferation of thymocytes are discussed.

Structure of branched DNA molecules: gel retardation and atomic force microscopy studies

DNA heteroduplexes as models for slipped strand DNA have been analyzed by polyacrylamide gel migration and atomic force microscopy (AFM). All heteroduplexes containing one hairpin or loop have reduced electrophoretic mobilities compared with that expected for their molecular weights. The retarded gel mobility correlates with the formation of a sharp kink detected by AFM. Increasing the hairpin length from 7 bp to 50 bp results in a monotonous decrease in gel mobility of heteroduplexes. This secondary retardation effect appears to depend only on the hairpin size since the AFM data show no dependence of the kink angle on the hairpin length. Heteroduplex isomers with a loop or hairpin in opposite strands migrate with distinct mobilities. Analysis of gel migration of heteroduplexes with altered hairpin orientations as well as of truncated heteroduplexes indicates that the difference in mobility is due to an inherent curvature in one of the long arms. This is confirmed by the end-to-end distance measurements from AFM images. In addition, significant variation of the end-to-end distances is consistent with a dynamic structure of heteroduplexes at the three-way junction. Double heteroduplexes containing one hairpin in each of the complementary strands also separate in a gel as two isomers. Their appearance in AFM showed a complicated pattern of flat representations of the three-dimensional structure and may indicate a certain degree of interaction between complementary parts of the hairpins that are several helical turns apart.

Social capital and self-rated health: a contextual analysis

OBJECTIVES

Social capital consists of features of social organization--such as trust between citizens, norms of reciprocity, and group membership--that facilitate collective action. This article reports a contextual analysis of social capital and individual self-rated health, with adjustment for individual household income, health behaviors, and other covariates.

METHODS

Self-rated health ("Is your overall health excellent, very good, good, fair, or poor?") was assessed among 167,259 individuals residing in 39 US states, sampled by the Behavioral Risk Factor Surveillance System. Social capital indicators, aggregated to the state level, were obtained from the General Social Surveys.

RESULTS

Individual-level factors (e.g., low income, low education, smoking) were strongly associated with self-rated poor health. However, even after adjustment for these proximal variables, a contextual effect of low social capital on risk of self-rated poor health was found. For example, the odds ratio for fair or poor health associated with living in areas with the lowest levels of social trust was 1.41 (95% confidence interval = 1.33, 1.50) compared with living in high-trust states.

CONCLUSIONS

These results extend previous findings on the health advantages stemming from social capital.