Brain mural cell loss in the parietal cortex in Alzheimer's disease correlates with cognitive decline and TDP-43 pathology

AIMS

Brain mural cells (BMC), smooth muscle cells and pericytes, interact closely with endothelial cells and modulate numerous cerebrovascular functions. A loss of BMC function is suspected to play a role in the pathophysiology of Alzheimer's Disease (AD).

METHODS

BMC markers, namely smooth muscle alpha actin (α-SMA) for smooth muscle cells, as well as platelet-derived growth factor receptor β (PDGFRβ) and aminopeptidase N (ANPEP or CD13) for pericytes, were assessed by Western immunoblotting in microvessel extracts from the parietal cortex of 60 participants of the Religious Orders study, with ages at death ranging from 75 to 98 years old.

RESULTS

Participants clinically diagnosed with AD had lower vascular levels of α-SMA, PDGFRβ and CD13. These reductions were correlated with lower cognitive scores for global cognition, episodic and semantic memory, perceptual speed and visuospatial ability. In addition, α-SMA, PDGFRβ and CD13 were negatively correlated with vascular Aβ40 concentrations. Vascular levels of BMC markers were also inversely correlated with insoluble cleaved phosphorylated transactive response DNA binding protein 43 (TDP-43) (25 kDa) and positively correlated with soluble cleaved phosphorylated TDP-43 (35 kDa) in cortical homogenates, suggesting strong association between BMC loss and cleaved phosphorylated TDP-43 aggregation.

CONCLUSIONS

The results of this study highlight a loss of BMC in AD. The associations between α-SMA, PDGFRβ and CD13 vascular levels with cognitive scores, TDP-43 aggregation and cerebrovascular accumulation of Aβ in the parietal cortex suggest that BMC loss contributes to both AD symptoms and pathology, further strengthening the link between cerebrovascular defects and dementia.

Trends in the use of laboratory tests for the diagnosis of Clostridium difficile infection and association with incidence rates in Quebec, Canada, 2010-2014

BACKGROUND

Several Clostridium difficile infection (CDI) surveillance programs do not specify laboratory strategies to use. We investigated the evolution in testing strategies used across Quebec, Canada, and its association with incidence rates.

METHODS

Cross-sectional study of 95 hospitals by surveys conducted in 2010 and in 2013-2014. The association between testing strategies and institutional CDI incidence rates was analyzed via multivariate Poisson regressions.

RESULTS

The most common assays in 2014 were toxin A/B enzyme immunoassays (EIAs) (61 institutions, 64%), glutamate dehydrogenase (GDH) EIAs (51 institutions, 53.7%), and nucleic acid amplification tests (NAATs) (34 institutions, 35.8%). The most frequent algorithm was a single-step NAAT (20 institutions, 21%). Between 2010 and 2014, 35 institutions (37%) modified their algorithm. Institutions detecting toxigenic C difficile instead of C difficile toxin increased from 14 to 37 (P < .001). Institutions detecting toxigenic C difficile had higher CDI rates (7.9 vs 6.6 per 10,000 patient days; P = .01). Institutions using single-step NAATs, GDH plus toxigenic cultures, and GDH plus cytotoxicity assays had higher CDI rates than those using an EIA-based algorithm (P < .05).

CONCLUSIONS

Laboratory detection of CDI has changed since 2010. There is an association between diagnostic algorithms and CDI incidence. Mitigation strategies are warranted.

Expression of E- and P-selectin in Tumor Necrosis Factor—induced Dermatitis in Dogs

Adhesion molecules on endothelial cells play an important role in leukocyte recruitment in several inflammatory processes. Vascular selectins mediate the initial adhesion of leukocytes to the blood vessel wall during their extravasation into inflamed tissues, and in vitro studies in dogs have shown that selectin expression can be induced by cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1). The objective of this study was to determine whether vascular selectins are induced by cytokines in vivo in a cutaneous model of inflammation in dogs. Skin biopsies were collected from nine dogs at various time points after an intradermal injection of TNF-α (10 ng/site) or phosphate-buffered saline containing 0.1% bovine serum albumin, and immunohistochemistry was performed using anti-P-selectin (MD3) and anti-E-selectin (CL37) monoclonal antibodies. In all animals, TNF-α induced an inflammatory reaction that was maximal at 12 hours and then decreased by 24 and 48 hours. Control skin displayed no expression of E- and P-selectin, whereas TNF-α induced the expression of P-selectin and E-selectin on dermal vessels that was highest at 12 hours and 3 hours, respectively ( P < 0.05). Numerous platelet aggregates recognized by the anti-P-selectin antibody were present in the lumina of vessels and in perivascular tissues. These results demonstrate that TNF-α can induce the expression of P- and E-selectin in vivo in dog skin and suggest that these selectins are involved in leukocyte recruitment in canine dermatitis.

Tobacco Use Among Adolescents Entering Quebec Youth Protection Centers

BACKGROUND: Every year between 4,000 and 5,000 adolescents reside in Quebec Youth Protection Centers (YPCs). Many of these adolescents use tobacco products and other psychotropic substances that impact their present and future well-being.

OBJECTIVES: Document the prevalence of tobacco use among youth residing in YPCs and identify associated factors. Describe the measures taken to implement policies for smoke-free environments in YPCs and promote smoking cessation counseling for youth in care.

DESIGN/METHODS: Between July 2008 and May 2009, adolescents aged 14-17 living in six YPCs across Quebec were recruited on a volunteer basis to participate in a surveillance study on health risk behaviors. Data on socio-demographics, lifetime substance use and sexual risk behaviors, as well as certain health consequences related to these behaviors were obtained during structured, face-to-face interviews. An analysis of factors associated with daily tobacco use was carried out.

RESULTS: Data regarding behaviors reported during the year prior to admission were collected among 499 participants (boys: 59%; median age: boys: 16; girls: 15). Lifetime tobacco use was reported by 93% of girls and 91% of boys (median age at first cigarette was 12 years). During the year prior to admission, 15% of youth reported no tobacco use, and 20% smoked occasionally. Two thirds (65%) reported daily tobacco use, with 36% of girls and 43% of boys smoking 10 or more cigarettes a day. In univariate analysis, factors significantly (p&lt;0.05) associated with daily smoking were: school failure or dropping out; family history of problematic alcohol or drug use; precocious initiation of alcohol use before age 13; history of regular use of alcohol or cannabis; problematic drug use (measured by DEP-ADO scale); having 6 or more lifetime sexual partners. Following dissemination of these results, measures were taken to develop a smoke-free policy and implementation plan for YPCs. Health professionals were trained to do brief interventions with all youth smokers entering care. In 2015 the YPC presented a brief to the provincial parlimentary committee on the Tobacco Act to support adoption of smoke-free policies for all health establishments in Québec.

CONCLUSION: Daily tobacco use is very prevalent among adolescents entering YPCs and the majority report problematic use of other psychoac-tive substances. Youth entering care merit screening for tobacco and drug use so that appropriate counseling can be initiated. Promoting policies that encourage smoke-free environments in child protection centers for both youth and the professionals working with them may greatly improve the chances for youth to live tobacco-free.

Phenotypical and functional profiles of natural killer cells exhibiting matrix metalloproteinase-mediated CD16 cleavage after anti-HIV antibody-dependent activation

Natural killer (NK) cell-mediated antibody-dependent cellular cytotoxicity (ADCC) has been linked to protection from HIV infection and slower progression towards AIDS. However, antibody-dependent activation of NK cells results in phenotypical alterations similar to those observed on NK cells from individuals with progressive HIV infection. Activation of NK cells induces matrix metalloproteinase (MMP)-mediated cleavage of cell surface CD16. In the present study we assessed the phenotype and functional profile of NK cells exhibiting post-activation MMP-mediated CD16 cleavage. We found that NK cells achieving the highest levels of activation during stimulation exhibit the most profound decreases in CD16 expression. Further, we observed that educated KIR3DL1(+) NK cells from human leucocyte antigen (HLA)-Bw4-carrying donors exhibit larger decreases in CD16 expression post-activation than the KIR3DL1(-) NK cell subset containing cells educated via other inhibitory receptor/ligand combinations and non-educated NK cells. Lastly, we assessed the ex-vivo expression of CD16 on educated KIR3DL1(+) NK cells and the KIR3DL1(-) NK cell subset from HLA-Bw4-carrying HIV-uninfected and HIV-infected donors. Suggestive of in-vivo activation of KIR3DL1(+) NK cells during HIV infection, CD16 expression was higher on KIR3DL1(+) than KIR3DL1(-) NK cells in uninfected donors but similar on both subsets in HIV-infected donors. These results are discussed in the context of how they may assist with understanding HIV disease progression and the design of immunotherapies that utilize antibody-dependent NK cell responses.

Healthcare-Associated Bloodstream Infections Secondary to a Urinary Focus The Québec Provincial Surveillance Results

Objective.

Urinary tract infections (UTIs) are an important source of secondary healthcare-associated bloodstream infections (BSIs), where a potential for prevention exists. This study describes the epidemiology of BSIs secondary to a urinary source (U-BSIs) in the province of Québec and predictors of mortality.

Design.

Dynamic cohort of 9,377,830 patient-days followed through a provincial voluntary surveillance program targeting all episodes of healthcare-associated BSIs occurring in acute care hospitals.

Setting.

Sixty-one hospitals in Québec, followed between April 1, 2007, and March 31, 2010.

Participants.

Patients admitted to participating hospitals for 48 hours or longer.

Methods.

Descriptive statistics were used to summarize characteristics of U-BSIs and microorganisms involved. Wilcoxon and X2 tests were used to compare U-BSI episodes with other BSIs. Negative binomial regression was used to identify hospital characteristics associated with higher rates. We explored determinants of mortality using logistic regression.

Results.

Of the 7,217 reported BSIs, 1,510 were U-BSIs (21%), with an annual rate of 1.4 U-BSIs per 10,000 patient-days. A urinary device was used in 71% of U-BSI episodes. Identified institutional risk factors were average length of stay, teaching status, and hospital size. Increasing hospital size was influential only in nonteaching hospitals. Age, nonhematogenous neoplasia, Staphylococcus aureus, and Foley catheters were associated with mortality at 30 days.

Conclusion.

U-BSI characteristics suggest that urinary catheters may remain in patients for ease of care or because practitioners forget to remove them. Ongoing surveillance will enable hospitals to monitor trends in U-BSIs and impacts of process surveillance that will be implemented shortly.

Soluble CD40-ligand (sCD40L, sCD154) plays an immunosuppressive role via regulatory T cell expansion in HIV infection

CD40/CD40-ligand (CD40L) signalling is a key stimulatory pathway which triggers the tryptophan (Trp) catabolizing enzyme IDO in dendritic cells and is immunosuppressive in cancer. We reported IDO-induced Trp catabolism results in a T helper type 17 (Th17)/regulatory T cell (Treg ) imbalance, and favours microbial translocation in HIV chronic infection. Here we assessed the link between sCD40L, Tregs and IDO activity in HIV-infected patients with different clinical outcomes. Plasmatic sCD40L and inflammatory cytokines were assessed in anti-retroviral therapy (ART)-naive, ART-successfully treated (ST), elite controllers (EC) and healthy subjects (HS). Plasma levels of Trp and its metabolite Kynurenine (Kyn) were measured by isotope dilution tandem mass spectrometry and sCD14 was assessed by enzyme-linked immunosorbent assay (ELISA). IDO-mRNA expression was quantified by reverse transcription-polymerase chain reaction (RT-PCR). The in-vitro functional assay of sCD40L on Treg induction and T cell activation were assessed on peripheral blood mononuclear cells (PBMCs) from HS. sCD40L levels in ART-naive subjects were significantly higher compared to ST and HS, whereas EC showed only a minor increase. In ART-naive alone, sCD40L was correlated with T cell activation, IDO-mRNA expression and CD4 T cell depletion but not with viral load. sCD40L was correlated positively with IDO enzymatic activity (Kyn/Trp ratio), Treg frequency, plasma sCD14 and inflammatory soluble factors in all HIV-infected patients. In-vitro functional sCD40L stimulation induced Treg expansion and favoured Treg differentiation by reducing central memory and increasing terminal effector Treg proportion. sCD40L also increased T cell activation measured by co-expression of CD38/human leucocyte antigen D-related (HLA-DR). These results indicate that elevated sCD40L induces immunosuppression in HIV infection by mediating IDO-induced Trp catabolism and Treg expansion.

Survey of infection control practices in hemodialysis units: preventing vascular access-associated bloodstream infections

OBJECTIVE

Despite surveillance, the Quebec Healthcare-Associated Infections Surveillance Program saw no improvement in vascular access-associated bloodstream infections in hemodialysis (HD). We aimed to determine the infection control measures recommended and implemented in Quebec's HD units, compliance of local protocols to infection control practice guidelines, and reasons behind the low prevalence of arteriovenous fistulas.

METHODS

An online survey was elaborated on the basis of the Centers for Disease Control and Prevention (CDC) and National Kidney Foundation Kidney Disease Outcomes Quality Initiative guidelines. The questionnaire was validated (construct, content, face validity, and reliability) and sent to all HD units in Quebec (n = 40). Results were analyzed using descriptive statistics, linear regression, and Poisson regression.

RESULTS

Thirty-seven (93%) of 40 HD units participated. Thirty (94%) of the 32 centers where central catheters are inserted have written insertion protocols. Compliance with practice guidelines is good, except for full-body draping during catheter insertion (79%) and ointment use at insertion site (3%). Prevention measures for catheter maintenance are in accordance with guidelines, except for skin disinfection with at least 0.5% chlorhexidine and 70% alcohol (67% compliance) and regular antiseptic ointment use at the insertion site (3%). Before fistula cannulation, skin preparation is suboptimal; forearm hygiene is performed in only 61% of cases. Several factors explain the low rate of fistulas, including patient preference (69%) and lack of surgical resources (39%; P = .01).

CONCLUSIONS

Improvement in standardization of care according to practice guidelines is necessary. Fistula rate could be increased by improving access to surgical resources and patient education. Strategies are now being elaborated to address these findings.

Accuracy of physician reporting in routine public health surveillance for hepatitis C virus infection

OBJECTIVE

From January 2007 to December 2008, the Montréal Public Health Department sent postal questionnaires to physicians and conducted patient interviews for all those newly diagnosed with hepatitis C virus (HCV) infection. We evaluated physician responses to risk factor questions for non-acute HCV cases.

METHODS

We compared physician and patient responses with each of nine risk factor questions, determined the sensitivity and specificity of physician responses compared with patient responses, and evaluated agreement using Gwet's agreement coefficient (AC1). We ranked risk factors and compared the distributions by principal exposure category according to physician reporting vs. patient interview using the Chi-square test.

RESULTS

The completeness of physicians' responses (yes, no, or unknown) varied by risk factor question from 90.8% to 96.7%. For risk factors present among more than 5% of cases, sensitivity of physician responses ranged from 26.9% to 87.7% and specificity ranged from 93.0% to 98.6%. The AC1 coefficients for agreement between physician and patient responses to lifetime risk factors considered most important in HCV acquisition were 0.80 for injection drug use, 0.95 for blood transfusion before 1990, and 0.86 for birth in a country with high HCV prevalence. Risk distributions by principal exposure category according to physician reporting vs. patient interview were not statistically different (χ(2)[4] = 2.17, p=0.704).

CONCLUSION

Postal questionnaires completed by physicians appear valid for determining the principal exposure category among non-acute HCV cases. Physician reporting can be a useful and low-cost component of routine HCV surveillance.

A survey of preventive measures used and their impact on central line-associated bloodstream infections (CLABSI) in intensive care units (SPIN-BACC)

BACKGROUND

The Quebec central line-associated bloodstream infections (CLABSI) in intensive care units (ICUs) Surveillance Program saw a decrease in CLABSI rates in most ICUs. Given the surveillance trends observed in recent years, we aimed to determine what preventive measures have been implemented, if compliance to measures was monitored and its impact on CLABSI incidence rates.

METHODS

All hospitals participating in the Quebec healthcare-associated infections surveillance program (SPIN-BACC - n = 48) received a 77-question survey about preventive measures implemented and monitored in their ICU. The questionnaire was validated for construct, content, face validity, and reliability. We used Poisson regression to measure the association between compliance monitoring to preventive measures and CLABSI rates.

RESULTS

Forty-two (88%) eligible hospitals completed the survey. Two components from the maximum barrier precautions were used less optimally: cap (88%) and full sterile body drape (71%). Preventive measures reported included daily review of catheter need (79%) and evaluation of insertion site for the presence of inflammation (90%). Two hospitals rewired lines even if an infection was suspected or documented.In adult ICUs, there was a statistically significant greater decrease in CLABSI rates in ICUs that monitored compliance to preventive insertion measures, after adjusting for teaching status and the number of hospital beds (p = 0.036).

CONCLUSIONS

Hospitals participating to the SPIN-BACC program follow recommendations for CLABSI prevention, but only a minority locally monitor their application. Compliance monitoring of preventive measures for catheter insertion was associated with a decrease in CLABSI incidence rates.

Central line-associated bloodstream infection in neonatal intensive care units

OBJECTIVE

Describe the epidemiology of central line-associated bloodstream infections (CLABSIs) in neonatal intensive care units (NICUs) participating in a standardized and mandatory CLABSI surveillance program.

DESIGN

Retrospective cohort. Setting. We included patients admitted (April 2007-March 2011) to 7 level II/III NICUs who developed a CLABSI (as defined by the National Healthcare Safety Network).

METHODS

CLABSIs/1,000 central line-days and device utilization ratio were calculated; χ(2) test, Student t test, Kruskal-Wallis, and Poisson regression were used.

RESULTS

Overall, 191 patients had 202 CLABSI episodes for a pooled mean rate of 4.0 CLABSIs/1,000 central line-days and a device utilization ratio of 0.20. Annual pooled mean CLABSI rates increased from 3.6 in 2007-2008 to 5.1 CLABSIs/1,000 central line-days in 2010-2011 (P - .01). The all-cause 30-day case fatality proportion was 8.9% (n = 17) and occurred a median of 8 days after CLABSI. Coagulase-negative Staphylococcus was identified in 112 (50.5%) cases. Staphylococcus aureus was identified in 22 cases, and 3 (13.6%) were resistant to methicillin. An underlying intra-abdominal pathology was found in 20% (40/202) of CLABSI cases, 50% of which were reported in the last year of study. When adjusted for mean birth weight, annual CLABSI incidence rates were independently associated with the proportion of intra-abdominal pathology (P = .007) and the proportion of pulmonary pathology (P = .016) reported.

CONCLUSION

The increase in CLABSI rates in Quebec NICUs seems to be associated with an increased proportion of cases with underlying intra-abdominal and pulmonary pathologies, which needs further investigation.

Sexual health of adolescents in Quebec residential Youth Protection Centres

OBJECTIVES

To document risk behaviours and prevalence of chlamydia and gonorrhoea infections among adolescents aged 14 to 17 years entering care in Quebec Youth Protection Centres (YPC).

METHODS

From July 2008 to May 2009, adolescents residing in six YPCs completed a questionnaire during a face-to-face interview. Questions covered sexual and substance use behaviours prior to admission, as well as other health issues affecting respondents' mental and physical health. Urine samples were tested for Chlamydia trachomatis genital infection (CTGI) and Neisseria gonorrhoea genital infection (NGGI).

RESULTS

Among 578 participants aged 14 to 17 years, 89% had had consensual sexual relations. Sexual risk behaviours included early sexual initiation (66% at <14 years); multiple partners (median lifetime number: girls 5, boys 8); 50% or more of sexual relations under the influence of drugs or alcohol (girls 43%, boys 48%); group sex (girls 38%, boys 43%); and sex in exchange for money or other goods (girls 27%, boys 8%). Only a quarter of boys and girls used double protection (condom and a contraceptive method) during the most recent vaginal relation. A history of pregnancy was reported by 28% of girls. Prevalence of CTGI was 9.3% (CI: 5.5-14.5) among girls and 1.9% (CI: 0.6-4.4) among boys. Prevalence of NGGI gonorrhoea was 1.7% (CI: 0.3-4.8) among girls and 0% (CI: 0.0-1.4) among boys.In multivariate analyses, factors significantly associated with chlamydia infection among sexually active girls were: hospitalization for alcohol intoxication; and a history of suicidal ideation with plan.

CONCLUSION

Sexual risk behaviours are common among adolescents entering YPCs, resulting in high levels of chlamydia infection. Mental health issues such as substance misuse and serious depressive symptoms are associated with these high rates. A youth's stay in these facilities is an opportune time to screen not only for sexual risk behaviours but also for mental health problems; appropriate risk reduction education and referrals can then be provided as needed.

Meeting report: Spontaneous lesions and diseases in wild, captive-bred, and zoo-housed nonhuman primates and in nonhuman primate species used in drug safety studies

The combination of loss of habitat, human population encroachment, and increased demand of select nonhuman primates for biomedical research has significantly affected populations. There remains a need for knowledge and expertise in understanding background findings as related to the age, source, strain, and disease status of nonhuman primates. In particular, for safety/biomedical studies, a broader understanding and documentation of lesions would help clarify background from drug-related findings. A workshop and a minisymposium on spontaneous lesions and diseases in nonhuman primates were sponsored by the concurrent Annual Meetings of the American College of Veterinary Pathologists and the American Society for Veterinary Clinical Pathology held December 3-4, 2011, in Nashville, Tennessee. The first session had presentations from Drs Lowenstine and Montali, pathologists with extensive experience in wild and zoo populations of nonhuman primates, which was followed by presentations of 20 unique case reports of rare or newly observed spontaneous lesions in nonhuman primates (see online files for access to digital whole-slide images corresponding to each case report at http://www.scanscope.com/ACVP%20Slide%20Seminars/2011/Primate%20Pathology/view.apml). The minisymposium was composed of 5 nonhuman-primate researchers (Drs Bradley, Cline, Sasseville, Miller, Hutto) who concentrated on background and spontaneous lesions in nonhuman primates used in drug safety studies. Cynomolgus and rhesus macaques were emphasized, with some material presented on common marmosets. Congenital, acquired, inflammatory, and neoplastic changes were highlighed with a focus on clinical, macroscopic, and histopathologic findings that could confound the interpretation of drug safety studies.

Knowledge, attitudes and behaviours associated with the provision of hepatitis C care by Canadian family physicians

The role of primary care physicians in providing care for hepatitis C virus (HCV) infection is increasingly emphasized, but many gaps and challenges remain. This study explores family physicians' knowledge, attitudes and practices associated with providing care for HCV infection. Seven hundred and forty-nine members of the College of Family Physicians of Canada (CFPC) completed a self-administered survey examining knowledge, attitudes and behaviours regarding HCV infection screening and care. Multivariate analyses were performed using the outcome, HCV care provision, and variables based on a conceptual model of practice guideline adherence. Family physicians providing basic-advanced HCV care were more likely to be older, practice in a rural setting, have injection drug users (IDU) in their practice and have higher levels of knowledge about the initial assessment (OR = 1.77; 95% CI = 1.23-2.54) and treatment of HCV (OR = 1.74; 95% CI = 1.24-2.43). They were also less likely to believe that family physicians do not have a role in HCV care (OR = 0.41; 95% CI = 0.30-0.58). Educational programmes should target physicians less likely to provide HCV care, namely family physicians practicing in urban areas and those who do not care for any IDU patients. Training and continuing medical education programmes that aim to shift family physicians' attitudes about the provision of HCV care by promoting their roles as integral to HCV care could contribute to easing the burden on consultant physicians and lead to improved access to treatment for HCV infection.

Correlates of unprotected anal sex at last sexual episode: analysis from a surveillance study of men who have sex with men in Montreal

Recent increases in rates of unprotected anal sex (UAS) among men who have sex with men (MSM) signal the need to continually refine our understanding of factors associated with risky sexual behavior. Data were collected using a questionnaire eliciting information about the last sexual episode (LSE) with another man in the past 6 months. Logistic regression was used to identify both event-level and background correlates of UAS at LSE. 965 participants who reported having sex with a partner with whom they were not in a couple relationship at LSE were studied. Several event-level variables were significantly associated with UAS after adjusting for background factors, including finding the partner at LSE sexually attractive and using alcohol or cocaine at LSE. Our findings parallel the results of other HIV prevention studies which have highlighted the importance of interpersonal factors that influence risk-taking at the moment of a sexual act among MSM.

Effect of antiretroviral therapy on HIV-1 genetic evolution during acute infection

The rapid evolution of HIV-1 is a major obstacle to viral eradication. Early antiretroviral therapy (ART) during primary HIV-1 infection could limit viral diversity. Eighteen patients recently infected with HIV-1 were selected. Nine initiated ART soon after enrolment and nine remained untreated. Replication-competent (RC) viruses were quantified at baseline and after one year of follow-up. Viral diversity in the C2V5 envelope region was evaluated from plasma, peripheral blood mononuclear cells (PBMCs), and cell culture at both time points. The amount of RC virus in the treated group declined (median −5.42 infectious units per million [IUPM]) while it remained stable or increased in the untreated group (median +0.87 IUPM). At one year post infection, we observed a significant increase in diversity for the C2V5 (+0.150%) region, specifically in the hypervariable loops V4 (+0.73%) and V5 (+0.77%), in the untreated group. More importantly, viral diversity did not significantly increase in treated individuals during the first year post infection. Genetic diversity during primary infection remains low through the first year of infection. Early treatment could contribute to a decrease in RC viruses from PBMCs and to limitation of viral diversification in the viral reservoir. These findings may have relevance for the rational design of specific immunotherapeutic strategies.

Diabetes and the severity of pandemic influenza A (H1N1) infection

OBJECTIVE

To confirm the existence of an increased risk of complications from influenza A (H1N1)p among patients with diabetes.

RESEARCH DESIGN AND METHODS

Using data from an enhanced influenza surveillance project in Montreal, Canada, and age/sex-specific population estimates of diabetes prevalence, we estimated the risk of hospitalization among persons with diabetes. Comparing hospitalized patients admitted or not to an intensive care unit (ICU), we estimated the risk of ICU admission associated with diabetes, controlling for other patient characteristics.

RESULTS

Among 239 hospitalized patients with PCR-confirmed influenza A (H1N1)p, 162 (68%) were interviewed, of whom 22 had diabetes, when 7.1 were expected (prevalence ratio 3.10 [95% CI 2.04-4.71]). The odds ratio for ICU admission was 4.29 (95% CI 1.29-14.3) among hospitalized patients with diabetes compared to those without.

CONCLUSIONS

Diabetes triples the risk of hospitalization after influenza A (H1N1)p and quadruples the risk of ICU admission once hospitalized.

Behavioural risks for HIV infection among Quebec residents of Haitian origin

Quebecers of Haitian origin (QHO) have the highest HIV prevalence of all immigrant groups in the province. We conducted a study among QHO to document the behavioural risk factors for HIV transmission. Male respondents were significantly more likely than female respondents to have at least one casual heterosexual partner in the past 12 months (39.7 vs. 18.8%, p < 0.001). Males were more likely to have used a condom at last sexual intercourse with a casual partner (78.9 vs. 53.7%; p = 0.002). However, among men who never, casually, or rarely used condoms with their regular female partner, 27.3% did not use a condom at last sexual intercourse with a casual partner. In the multivariable logistic regression analysis, having at least one casual heterosexual partner in the past 12 months was associated with being younger than 29 years, being male, being single, and being a second-generation QHO. This study allows us to identify subgroups whose behaviours can result in greater vulnerability to HIV infection and other STIs.

High level of primary drug resistance in Mali

BACKGROUND

As access to antiretroviral drugs increases in developing countries, it will become increasingly important to monitor the emergence of resistance and to define the molecular pathways involved to identify optimal therapeutic regimens.

METHODS

We performed genotypic resistance testing on plasma obtained from 101 HIV-infected treatment-naïve individuals from Mali. Genotyping was carried out using the Virco protocols and HXB2 was used as the reference strain.

RESULTS

CRF02_AG was the most common subtype, present in 71.3% of our patient population. Other subtypes included B, C, G, CRF06_CPX, CRF09_CPX, CRF01_AE, A2/CRF16_A2D, A1 and CRF13_CPX. A total of 9.9% [95% confidence interval (CI) 6.9-12.9%] of patients had at least one resistance mutation. The prevalences of mutations conferring resistance to nucleoside reverse transcriptase inhibitors (NRTIs), nonnucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs) were 5% (95% CI 0.7-9.2%), 6% (95% CI 1.3-10.6%) and 0%, respectively. The most frequent mutations were T215A/Y for NRTIs and K103N/T for NNRTIs. One patient harboured three NRTI resistance mutations and one NNRTI mutation. This is the first reported case of multi-drug-resistant viral transmission in Mali. Polymorphisms at protease codons 10I/V and 33F potentially associated with resistance were observed in 18.8% and 1% of patients, respectively. Several polymorphisms in the C-terminal domain of reverse transcriptase were observed: A371V (in 63.4% of patients), G335D (76.2%), E399D (10.9%) and G333E (1%).

CONCLUSION

Primary resistance was seen in 9.9% of subjects, which is higher than previously reported in Mali. Taking into consideration other polymorphisms in protease such as L10I/V and 33F, primary resistance could reach 28.7% (95% CI 19.9-37.5%). Our study reflects the need to monitor the evolution of resistance on a regular basis and trends of transmitted resistance.

Assessment of exposure to pyrethroids and pyrethrins in a rural population of the Montérégie area, Quebec, Canada

Pesticide use remains a preoccupation of the population and public health authorities given its possible impact on health. Pyrethroids can be listed among the widely used pesticides. The general population is potentially chronically exposed to pyrethroids mainly through food intake, but acute or sporadic exposures can also occur by other routes. Although pyrethroids are considered among the least toxic pesticides, their neurotoxic properties can affect humans, but current exposure levels in the population of Quebec are not known. The study thus aimed at assessing pyrethroid exposure in a rural, agricultural population during summer through measurements of urinary biomarkers. A total of 163 volunteers, 49 children and 114 adults, living in the Montérégie area of Quebec, participated in the study, which took place from June to August 2006, the period of intensive application of pesticides. Participants were asked to collect all their micturitions from 6 p.m. until the next morning, including first morning void, and to fill out a questionnaire to document factors that could potentially contribute to exposure. A gas-chromatography mass-spectrometry method was used to quantify six urinary metabolites resulting from pyrethroid biotransformation: cis- and trans-2,2-(dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (cDCCA and tDCCA), 3-phenoxybenzoic acid (PBA), chrysanthemum dicarboxylic acid (CDCA), cis-2,2-(dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid (DBCA) and 4-fluoro-3-phenoxybenzoic acid (FPBA). Distributions of amounts of the six metabolites excreted per unit of body weight, during a standardized 12-hr period, followed the same decreasing pattern in adults and in children: tDCCA > PBA > cDCCA > CDCA > DBCA > FPBA. No statistically significant difference was observed between the two groups, but amounts of metabolites varied greatly among individuals, suggesting important interindividual variations in the absorbed doses of these compounds. No consistent associations were observed between the excretion of correlated metabolites and the various factors documented by questionnaire (personal factors, life habits, sources of exposure). Comparison of the current data with those observed in an urban population of the same province during the summer of 2005 suggests a greater summertime exposure to some pyrethroids in the rural population.

Repeated measures of validated and novel biomarkers of exposure to polycyclic aromatic hydrocarbons in individuals living near an aluminum plant in Quebec, Canada

A longitudinal biomonitoring study was conducted to assess exposure to polycyclic aromatic hydrocarbons (PAH) in non-occupationally exposed nonsmoking adults living in the vicinity of an aluminum plant. Metabolites of several PAH (pyrene, naphthalene, chrysene, fluoranthene, benz[a]anthracene) were measured in the urine of the participants, including 1-hydroxypyrene (1-OHP) as a validated biomarker and pyrene diones as novel biomarkers. In total, 73 individuals living about 1 km away from the plant (taken as the exposed group) were compared repeatedly with 71 individuals living at least 11 km from the smelter (used as the control group). Complete first morning voids were collected twice, at a 2-wk interval, in the fall of 2005 and twice weekly for 2 consecutive weeks in the spring of 2006. Urinary biomarker concentrations were then measured by an ultra-performance liquid chromatography (UPLC) method with time-of-flight mass spectrometry detection (MS-TOF) (UPLC-MS-TOF). For most sampling days, individuals living near the plant showed significantly higher excretion values of both 1-OHP and pyrene diones (mean ratio up to 2- and 2.4-fold, respectively) than individuals living further from the plant. In the group living near the plant, geometric mean concentrations of 1-OHP varied from 0.047 to 0.058 micromol/mol creatinine, depending on the sampling day, as compared to 0.025 to 0.04 micromol/mol creatinine in the reference group. Corresponding mean values for pyrene diones were 0.017-0.056 micromol/mol creatinine and 0.014-0.039 micromol/mol creatinine, respectively. Urinary 1- and 2-naphthols were also measured as a reference and showed no significant differences between the two groups for most sampling days; metabolite concentrations of the other monitored PAH (chrysene, fluoranthene, benz[a]anthracene) were mostly below the analytical limit of detection of 0.005 to 0.01 microg/L, depending on the metabolite, with a detection rate varying from 0 to at most 21%. Individuals living near the aluminum plant thus appeared to be repeatedly exposed to higher pyrene levels than the control group, on the basis of both 1-OHP and pyrene dione excretions. However, 1-OHP concentrations observed in this first group were similar to those of other reference populations of nonsmokers studied in the past. Uptake of the other PAH associated with plant emissions was too small to significantly increase the excretion of their metabolites.

Access to sterile injecting equipment is more important than awareness of HCV status for injection risk behaviors among drug users

Awareness of hepatitis C virus (HCV) infection status is expected to influence risk behaviors. In 2004-2005, injection drug users (IDUs) recruited from syringe exchange programs (SEPs) and methadone clinics in Montreal, Canada, were interviewed on drug use behaviors (past 6 months) and HCV testing. Subjects (n = 230) were classified as low/intermediate risk (20.4% borrowed drug preparation equipment only) and high risk (19.6% borrowed syringes), and 54.5% reported being HCV positive. Logistic regression modeling showed that compared to no risk (60% borrowed nothing), low/intermediate risk was associated with fewer noninjecting social network members, poor physical health, and problems obtaining sterile injecting equipment. High risk was associated with all of these factors except social networks. HCV status was not associated with any level of risk. Improved access to sterile injecting equipment may be more important than knowledge of HCV status in reducing injection risks among this IDU population. The study limitations are noted and recommendations discussed.

High dietary consumption of trans fatty acids decreases brain docosahexaenoic acid but does not alter amyloid-beta and tau pathologies in the 3xTg-AD model of Alzheimer's disease

Dietary consumption of trans fatty acids (TFA) has increased during the 20th century and is a suspected risk factor for cardiovascular diseases. More recently, high TFA intake has been associated with a higher risk of developing Alzheimer's disease (AD). To investigate the impact of TFA on an animal model genetically programmed to express amyloid-beta (Abeta) and tau pathological markers of AD, we have fed 3xTg-AD mice with either control (0% TFA/total fatty acid), high TFA (16% TFA) or very high TFA (43% TFA) isocaloric diets from 2 to 16 months of age. Effects of TFA on plasma hepatic enzymes, glucose and lipid profile were minimal but very high TFA intake decreased visceral fat of non-transgenic mice. Importantly, dietary TFA increased brain TFA concentrations in a dose-related manner. Very high TFA consumption substantially modified the brain fatty acid profile by increasing mono-unsaturated fatty acids and decreasing polyunsaturated fatty acids (PUFA). Very high TFA intake induced a shift from docosahexaenoic acid (DHA, 22:6n-3) toward n-6 docosapentaenoic acid (DPA, 22:5n-6) without altering the n-3:n-6 PUFA ratio in the cortex of both control and 3xTg-AD mice. Changes in levels of Abeta(40), Abeta(42), tau protein, phosphorylated tau protein and synaptic markers were not statistically significant in the three groups of 3xTg-AD mice, despite a trend toward decreased insoluble tau in very high TFA-fed 3xTg-AD animals. In summary, TFA intake modulated brain fatty acid profiles but had no significant effect on major brain neuropathological hallmarks of AD in an animal model.

Persistent human immunodeficiency virus-1 antigenaemia affects the expression of interleukin-7Ralpha on central and effector memory CD4+ and CD8+ T cell subsets

Interleukin (IL)-7 and its receptor (IL-7Ralpha) play important roles in regulating lymphopoiesis. Previous studies have reported that human immunodeficiency virus-1 (HIV-1) viraemia affects the expression of IL-7Ralpha, but its effects on CD4+ and CD8+ T cell memory subsets have not been studied. Using eight-colour flow cytometry, we compared the immunophenotypic patterns of CD4+ and CD8+ T cell subsets expressing IL-7Ralpha and activation markers, as well as circulating IL-7 levels, in three well-defined groups of HIV-1-infected subjects: successfully treated, viraemic and long-term non-progressor (LTNP). Compared with successfully treated and LTNP subjects, viraemic patients had reduced expression of IL-7Ralpha on both CD4+ and CD8+ T cells, particularly on central and effector memory T cell compartments, and substantially elevated expression of activation markers on CD8+ T cell subsets. Circulating IL-7 levels were correlated negatively with the number of CD4+ and CD8+ T cell subsets expressing IL-7Ralpha; these associations were stronger with CD4+ T cell subsets and mainly with central and effector memory cells. The expression of activation markers on CD4+ and CD8+ cell T subsets was not related to circulating IL-7 levels. A strong negative correlation was observed between central memory CD4+ or CD8+ T cells expressing IL-7Ralpha and those expressing activation markers, independently of IL-7 levels. Collectively, these results provide further insight on the role of unsuppressed viral load in disrupting the IL-7/IL-7Ralpha system and contributing to HIV-1 disease progression.