Implementing community-based Dried Blood Spot (DBS) testing for HIV and hepatitis C: a qualitative analysis of key facilitators and ongoing challenges

Background

In 2018, the Community-Based Research Centre (CBRC) invited gay, bisexual, trans, queer men and Two-Spirit and non-binary people (GBT2Q) at Pride Festivals across Canada to complete in-person Sex Now surveys and provide optional dried blood spot (DBS) samples screening for human immunodeficiency virus (HIV) and hepatitis C virus (HCV). As there is a lack of research evaluating the implementation of DBS sampling for GBT2Q in community settings, we aimed to evaluate this intervention, identifying key facilitators and ongoing challenges to implementing community-based DBS screening for HIV/HCV among GBT2Q.

Methods

We conducted sixteen one-on-one interviews with individuals involved with the community-based DBS collection protocol, including research staff, site coordinators, and volunteer DBS collectors. Most individuals involved with DBS collection were “peers” (GBT2Q-identified). The Consolidated Framework for Implementation Research (CFIR) guided our data collection and analysis.

Results

Interviewees felt that DBS collection was a low-barrier, cost-effective, and simple way for peers to quickly screen a large number of Sex Now respondents. Interviewees also noted that the community and peer-based aspects of the research helped drive recruitment of Sex Now respondents. Most interviewees felt that the provision of results took too long, and that some Sex Now respondents would have preferred to receive their test results immediately (e.g., rapid or point-of-care testing).

Conclusion

Peer-based DBS sampling can be an effective and relatively simple way to screen GBT2Q at Pride Festivals for more than one sexually transmitted and blood borne infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13525-x.

Estimating nutritional needs in paediatric heart failure: beyond the equations

BACKGROUND

Nutrition optimisation is imperative in paediatric patients with heart failure. Energy needs can be assessed using indirect calorimetry.

METHODS

Presented are two cases of children with clinical heart failure who benefited from indirect calorimetry.

RESULTS

Using indirect calorimetry, it was determined both cases were hypermetabolic.

CONCLUSION

These cases demonstrate the impact of heart failure on metabolic rate and growth. Energy requirements were up to two times higher than estimations from predictive equations.

Growth Faltering and Developmental Delay in HIV-Exposed Uninfected Ugandan Infants: A Prospective Cohort Study

BACKGROUND

HIV-exposed but uninfected (HEU) infants are at increased risk of impaired early linear growth and cognitive development. We examined associations between prenatal and postnatal growth and subsequent neurodevelopment in Ugandan HEU infants, hypothesizing that early insults may explain alterations in both somatic growth and brain development.

METHODS

We prospectively followed a cohort of HEU infants from birth to 18 months of age, and measured length/height, weight, head, and arm circumference longitudinally. The Malawi Development Assessment Tool (MDAT, 12 and 18 months) and the Color Object Association Test (18 months) were used for developmental assessments.

RESULTS

Among 170 HEU infants, the prevalence of low-birth weight and failure to thrive was 7.6% and 37%, respectively. HEU infants had MDAT scores that were similar to the reference population. The mean (SD) score on the Color Object Association Test was 5.5 (3.1) compared with 6.9 (5.3) in developmentally normal children. Developmental ability at age 18 months showed strong cross-sectional correlation with weight-for-age (ρ = 0.36, P < 0.0001), length/height-for-age (ρ = 0.41, P < 0.0001), head circumference-for-age (ρ = 0.26, P = 0.0011), and mid-upper arm circumference-for-age (ρ = 0.34, P = 0.0014). There was a statistically significant correlation between birth weight and MDAT z-score at 18 months (ρ = 0.20, P = 0.010). Failure to thrive was associated with lower MDAT z-score [median -0.13 (IQR -0.75 to +0.14) versus +0.14 (IQR -0.44 to +0.63), P = 0.042].

CONCLUSION

Growth faltering in HEU infants was associated with lower attainment of developmental milestones at age 18 months. Our findings point to a simple screening method for identifying HEU infants at risk for developmental intervention.

Clinical Correlates of Human Immunodeficiency Virus-1 (HIV-1) DNA and Inducible HIV-1 RNA Reservoirs in Peripheral Blood in Children With Perinatally Acquired HIV-1 Infection With Sustained Virologic Suppression for at Least 5 Years

BACKGROUND

The Early Pediatric Initiation Canada Child Cure Cohort (EPIC4) study is a prospective, multicenter, Canadian cohort study investigating human immunodeficiency virus-1 (HIV-1) reservoirs, chronic inflammation, and immune responses in children with perinatally acquired HIV-1 infection. The focus of this report is HIV-1 reservoirs and correlates in the peripheral blood of children who achieved sustained virologic suppression (SVS) for ≥5 years.

METHODS

HIV-1 reservoirs were determined by measuring HIV-1 DNA in peripheral blood mononuclear cells and inducible cell-free HIV-1 RNA in CD4+ T-cells by a prostratin analogue stimulation assay. HIV serology was quantified by signal-to-cutoff ratio (S/CO).

RESULTS

Of 228 enrolled participants, 69 achieved SVS for ≥5 years. HIV-1 DNA, inducible cell-free HIV-1 RNA, and S/COs correlated directly with the age of effective combination antiretroviral therapy (cART) initiation (P < .001, P = .036, and P < .001, respectively) and age when SVS was achieved (P = .002, P = .038, and P < .001, respectively) and inversely with the proportion of life spent on effective cART (P < .001, P = .01, and P < .001, respectively) and proportion of life spent with SVS (P < .001, P = .079, and P < .001, respectively). Inducible cell-free HIV-1 RNA correlated with HIV-1 DNA, most particularly in children with SVS, without virologic blips, that was achieved with the first cART regimen initiated prior to 6 months of age (rho = 0.74; P = .037) or later (rho = 0.87; P < .001). S/COs correlated with HIV-1 DNA (P = .003), but less so with inducible cell-free HIV-1 RNA (P = .09).

CONCLUSIONS

The prostratin analogue stimulation assay, with its lower blood volume requirement, could be a valuable method for evaluating inducible HIV-1 reservoirs in children. Standard commercial HIV serology may be a practical initial indirect measure of reservoir size in the peripheral blood of children with perinatally acquired HIV-1 infection.

Distress related to attenuated psychotic symptoms: Static and dynamic association with transition to psychosis, non-remission and transdiagnostic symptomatology in clinical high-risk patients in an international intervention trial

This study examined whether distress in relation to attenuated psychotic symptoms (DAPS) is associated with clinical outcomes in an ultra-high-risk (UHR) for psychosis sample. We also investigated whether DAPS is associated with cognitive style (attributional style and cognitive biases) and whether amount of psychosocial treatment provided is associated with reduction in DAPS. The study was a secondary analysis of the ‘Neurapro’ clinical trial of omega-3 fatty acids. 304 UHR patients were recruited across ten early intervention services. Data from baseline assessment, regular assessments over 12 months and medium term follow up (mean=3.4 years) were used for analysis. Findings indicated: a positive association between DAPS assessed over time and transition to psychosis; a significant positive association between baseline and longitudinal DAPS and transdiagnostic clinical and functional outcomes; a significant positive association between baseline and longitudinal DAPS and non-remission of UHR status. There was no relationship between severity of DAPS and cognitive style. A greater amount of psychosocial treatment (cognitive-behavioural case management) was associated with an increase in DAPS scores. The study indicates that UHR patients who are more distressed by their attenuated psychotic symptoms are more likely to have a poorer clinical trajectory transdiagnostically. Assessment of DAPS may therefore function as a useful marker of risk for a range of poor outcomes. The findings underline the value of repeated assessment of variables and incorporation of dynamic change into predictive modelling. More research is required into mechanisms driving distress associated with symptoms and the possible bidirectional relationship between symptom severity and associated distress.

Peritonitis in Continuous Ambulatory Peritoneal Dialysis {CAPD): A Multi-Centre Randomized Clinical Trial Comparing the Y Connector Disinfectant System to Standard Systems

sixty-one new continuous ambulatory peritoneal dialysis (CAPD) patients were allocated to a Y connector disinfectant (Amuchina, Italy) and 63 to standard systems (Baxter Systems II & III) in a randomized clinical trial addressing peritonitis rates in 8 CAPD programs in 6 Canadian cities. In the Y connector-disinfectant group, 15 patients experienced 21 episodes of peritonitis in 452 patient-months or 1 per 21.53 patient-months. In the standard systems group, 30 patients experienced 47 episodes of peritonitis in 467 patient-months or 1 per 9.93 patient-months ( p = 0.009). The peritonitis risk reduction was 61% (95% confidence limits 27–79%). Exit-site infections occurred in 36% of each group.

Prior to the development of exit -site infection, the monthly risk for peritonitis was 3.12% for the Y connector disinfectant system and 7.37% for the standard system. After an exit -site infection, these probabilities increased to 6.15% and 15.47%, respectively. Skin organisms were responsible for peritonitis in 8/21 (38%) in the Y connector-disinfectant group and 30/47 (64%) in the standard group. There were 75 days hospitalized for peritonitis in the Y connector-disinfectant group compared to 257 days for the standard group. The Y connector disinfectant system decreases the peritonitis rate through its effect on skin organisms. Exit -site infections are a major source of organisms responsible for peritonitis.

Basic symptoms in young people at ultra-high risk of psychosis: Association with clinical characteristics and outcomes

There has been limited research into the predictive value of basic symptoms and their relationship with other psychopathology in patients identified using the 'ultra high risk' (UHR) for psychosis approach. The current study investigated whether basic symptoms, specifically cognitive disturbances (COGDIS), were associated with a greater risk of transition to psychotic disorder and persistent attenuated psychotic symptoms (APS) at medium term follow-up (mean = 3.4 years) in UHR patients, as well as with general psychopathology at baseline. The sample included 304 UHR participants (mean age = 19.12 years) involved in an international multicenter trial of omega-3 fatty acids. UHR individuals who also met the COGDIS criteria (basic symptoms risk criteria) did not have a greater risk of transition than those who met the UHR criteria alone. However, meeting COGDIS risk criteria was associated with a greater likelihood of meeting the UHR attenuated psychotic symptoms risk group (i.e., having persistent attenuated psychotic symptoms) at 12-month follow-up (odds ratio = 1.85; 95% CI = 1.03, 3.32). Greater severity of cognitive basic symptoms was also independently associated with more severe general psychopathology at study entry. The findings do not support the notion that combined risk identification approaches (UHR and basic symptoms) aid in the identification of individuals at greatest risk of psychosis, although this interpretation is limited by the modest transition to psychosis rate (13%) and the time of follow up. However, the findings indicate that basic symptoms may be a clinically useful marker of more severe general psychopathology in UHR groups and risk for persistent attenuated psychotic symptoms.

Dynamic prediction of transition to psychosis using joint modelling

Considerable research has been conducted seeking risk factors and constructing prediction models for transition to psychosis in individuals at ultra-high risk (UHR). Nearly all such research has only employed baseline predictors, i.e. data collected at the baseline time point, even though longitudinal data on relevant measures such as psychopathology have often been collected at various time points. Dynamic prediction, which is the updating of prediction at a post-baseline assessment using baseline and longitudinal data accumulated up to that assessment, has not been utilized in the UHR context. This study explored the use of dynamic prediction and determined if it could enhance the prediction of frank psychosis onset in UHR individuals. An emerging statistical methodology called joint modelling was used to implement the dynamic prediction. Data from the NEURAPRO study (n = 304 UHR individuals), an intervention study with transition to psychosis study as the primary outcome, were used to investigate dynamic predictors. Compared with the conventional approach of using only baseline predictors, dynamic prediction using joint modelling showed significantly better sensitivity, specificity and likelihood ratios. As dynamic prediction can provide an up-to-date prediction for each individual at each new assessment post entry, it can be a useful tool to help clinicians adjust their prognostic judgements based on the unfolding clinical symptomatology of the patients. This study has shown that a dynamic approach to psychosis prediction using joint modelling has the potential to aid clinicians in making decisions about the provision of timely and personalized treatment to patients concerned.

Disturbed glutathione antioxidative defense is associated with structural brain changes in neuroleptic-naïve first-episode psychosis patients

BACKGROUND

Oxidative stress and impaired antioxidant defense are reported in schizophrenia and are thought to be associated with disturbed neurodevelopment, brain structural alterations, glutamatergic imbalance, negative symptomatology, and cognitive impairment. To test some of these assumptions we investigated the glutathione (GSH) antioxidant defense system (AODS) and brain structural abnormalities in drug-naïve individuals with first acute episode of psychosis (FEP).

METHOD

The study involved 27 drug-naïve FEP patients and 31 healthy controls (HC). GSH AODS markers and TBARS (thiobarbituric acid reactive substances) were measured in blood plasma and erythrocytes. High-resolution T₁-weighted 3T MRI were acquired from all subjects. To investigate brain structural abnormalities and effects of illness on interactions between GSH metabolites or enzyme activities and local grey matter density, voxel-based morphometry (VBM) with the computational anatomy toolbox (CAT12) was used. Symptomatology was assessed using the Positive and Negative Syndrome Scale (PANSS) and the Symptom Checklist 1990 revised (SCL-90-R).

RESULTS

(i) In FEP patients, glutathione reductase activity (GSR) was lower than in the HC group. GSR activity in plasma was inversely correlated with SCL-90-R scores of depression and PANSS scores of the negative symptom subscale. (ii) A reduction of GM was observed in left inferior frontal, bilateral temporal, as well as parietal cortices of FEP patients. (iii) Interaction analyses revealed an influence of illness on GSR/GM associations in the left orbitofrontal cortex (BA 47).

CONCLUSION

Our findings support the notion of altered GSH antioxidative defense in untreated acute psychosis as a potential pathomechanism for localized brain structural abnormalities. This pathology relates to a key brain region of social cognition, affective motivation control and decision making, and is clinically accompanied by depressive and negative symptoms.

NEURAPRO: a multi-centre RCT of omega-3 polyunsaturated fatty acids versus placebo in young people at ultra-high risk of psychotic disorders-medium-term follow-up and clinical course

This study reports a medium-term follow-up of a randomised, double-blind, placebo-controlled trial of omega-3 polyunsaturated fatty acids (PUFA) in ultra-high risk for psychosis (UHR) patients. Primary outcomes of interest were transition to psychosis and symptomatic and functional outcome. A secondary aim was to investigate clinical predictors of medium-term outcome. Three hundred four UHR participants were recruited across 10 specialised early psychosis services in Australia, Asia, and Europe. The intervention consisted of 1.4 g/daily of omega-3 PUFA or placebo, plus up to 20 sessions of cognitive-behavioural case management (CBCM), over the 6-month study period, with participants receiving further CBCM sessions on basis of need between months 6-12. Mean time to follow-up was 3.4 (median = 3.3; SD = 0.9) years. There was a modest increase in transitions between 12-month and medium-term follow-up (11-13%) and substantial improvement in symptoms and functioning between baseline and follow-up, with no differences between the treatment groups. Most improvement had been achieved by end of the intervention. 55% of the sample received mental health treatment between end of intervention and follow-up. Omega-3 PUFA did not provide additional benefits to good quality psychosocial intervention over the medium term. Although most improvement had been achieved by end of intervention the substantial rates of post-intervention mental health service use indicate longer-term clinical need in UHR patients. The post-intervention phase treatment or the longer-term effect of CBCM, or a combination of the two, may have contributed to maintaining the gains achieved during the intervention phase and prevented significant deterioration after this time.

Heterophilic interference in specimens yielding false-reactive results on the Abbott 4th generation ARCHITECT HIV Ag/Ab Combo assay

BACKGROUND

False-reactivity in HIV-negative specimens has been detected in HIV fourth-generation antigen/antibody or 'combo' assays which are able to detect both anti-HIV-1/HIV-2 antibodies and HIV-1 antigen.

OBJECTIVES

We sought to characterize these specimens and determine the effect of heterophilic interference.

STUDY DESIGN

Specimens previously testing as false-reactive on the Abbott ARCHITECT HIV Ag/Ab combo assay and re-tested on a different (Siemens ADVIA Centaur HIV Ag/Ab) assay. A subset of these specimens were also pre-treated with heterophilic blocking agents and re-tested on the Abbott assay.

RESULTS

Here we report that 95% (252/264) of clinical specimens that were repeatedly reactive on the Abbott ARCHITECT HIV Ag/Ab combo assay (S/Co range, 0.94-678) were negative when re-tested on a different fourth generation HIV combo assay (Siemens ADVIA Centaur HIV Ag/Ab). All 264 samples were subsequently confirmed to be HIV negative. On a small subset (57) of specimens with available volume, pre-treatment with two different reagents (HBT; Heterophilic Blocking Tube, NABT; Non-Specific Blocking Tube) designed to block heterophilic antibody interference either eliminated (HBT) or reduced (NABT) the false reactivity when re-tested on the ARCHITECT HIV Ag/Ab combo assay.

CONCLUSIONS

Our results suggest that the Abbott ARCHITECT HIV Ag/Ab combo assay can be prone to heterophilic antibody interference.

HIV misdiagnosis: A root cause analysis leading to improvements in HIV diagnosis and patient care

BACKGROUND

Standard diagnostic testing for HIV infection has traditionally relied on a high sensitivity HIV antibody screening test using an enzyme-linked immunosorbent assay (ELISA) followed by a high specificity antibody confirmatory test such as a Western Blot. Recently several of the screening assays have been enhanced with an ability to identify p24 antigen thereby narrowing the diagnostic window.

OBJECTIVES

To explore the implications of enhanced HIV screening methods that may be leading to HIV misdiagnoses.

STUDY DESIGN

A patient deemed to be an HIV infected 'elite controller' was found to be misdiagnosed when undergoing detailed investigations prior to initiating antiretroviral therapy. A root cause analysis was performed to identify the causative factors of this misdiagnosis. A retrospective review of all "elite controllers" in Alberta, Canada revealed challenges of current HIV testing algorithms.

RESULTS

Technical and human factors were identified as being causative in this HIV misdiagnosis including (i) high rates of false reactive results on the Abbott ARCHITECT HIV-1&2 COMBO EIA, (ii) human error in reading the initial Western blot, (iii) HIV algorithmic directives in which confirmatory (Western blot) testing was not performed on a repeatedly reactive screen test. The outcome of this analysis identified opportunities for improvement, including implementation of a newly approved (automated) confirmatory assay and improved communication between the clinician and laboratory.

CONCLUSIONS

HIV testing remains problematic despite significant advances in HIV test performance and algorithm development, presenting new and unexpected issues. Ensuring a high-quality management system including implementation of the latest HIV technologies and algorithms along with human resources and policies are required to minimize the impact of false positive diagnoses, especially in the era of universal screening and 'test and treat' recommendations.

Prediction of transition from ultra-high risk to first-episode psychosis using a probabilistic model combining history, clinical assessment and fatty-acid biomarkers

Current criteria identifying patients with ultra-high risk of psychosis (UHR) have low specificity, and less than one-third of UHR cases experience transition to psychosis within 3 years of initial assessment. We explored whether a Bayesian probabilistic multimodal model, combining baseline historical and clinical risk factors with biomarkers (oxidative stress, cell membrane fatty acids, resting quantitative electroencephalography (qEEG)), could improve this specificity. We analyzed data of a UHR cohort (n=40) with a 1-year transition rate of 28%. Positive and negative likelihood ratios were calculated for predictor variables with statistically significant receiver operating characteristic curves (ROCs), which excluded oxidative stress markers and qEEG parameters as significant predictors of transition. We clustered significant variables into historical (history of drug use), clinical (Positive and Negative Symptoms Scale positive, negative and general scores and Global Assessment of Function) and biomarker (total omega-3, nervonic acid) groups, and calculated the post-test probability of transition for each group and for group combinations using the odds ratio form of Bayes' rule. Combination of the three variable groups vastly improved the specificity of prediction (area under ROC=0.919, sensitivity=72.73%, specificity=96.43%). In this sample, our model identified over 70% of UHR patients who transitioned within 1 year, compared with 28% identified by standard UHR criteria. The model classified 77% of cases as very high or low risk (P>0.9, <0.1) based on history and clinical assessment, suggesting that a staged approach could be most efficient, reserving fatty-acid markers for 23% of cases remaining at intermediate probability following bedside interview.

Early Initiation Rather Than Prolonged Duration of Antiretroviral Therapy in HIV Infection Contributes to the Normalization of CD8 T-Cell Counts

BACKGROUND

CD8 T-cell counts remain elevated in human immunodeficiency virus (HIV) infection even after long-term antiretroviral therapy (ART), which is associated with an increased risk of non-AIDS-related events. We assessed the impact of ART initiation in early versus chronic HIV infection on trajectories of CD8 cell counts over time.

METHODS

Of 280 individuals enrolled during primary HIV infection (PHI), 251 were followed up for 24 months; 84 started ART before 6 months of infection (eART), 49 started between 6 and 24 months, and 118 remained untreated. Plasma HIV viral load (VL), CD4 and CD8 cell counts were assessed at each study visit. CD8 counts were also examined in 182 age-matched HIV-infected individuals who started ART during chronic infection and maintained undetectable plasma VL for ≥5 years.

RESULTS

At PHI baseline, higher CD8 cell counts were associated with more recent infection (P = .02), higher CD4 cell counts (P < .001), and higher VL (P < .001). The CD8 count in the eART group decreased from 797 to 588 cells/µL over 24 months (P < .001), to a level lower than that in untreated PHI (834 cells/µL; P = .004) or in long-term-treated patients with chronic HIV infection (743 cells/µL; P = .047). More prominent CD4 T-cell recovery was observed in the eART group than in the delayed ART group.

CONCLUSIONS

ART initiated in early HIV infection is associated with improved resolution of CD8 T-cell elevation compared with long-term ART initiated in chronic infection. Early ART may help reduce the risk of non-AIDS-related events by alleviating this elevation.

What are the neurocognitive correlates of basic self-disturbance in schizophrenia?: Integrating phenomenology and neurocognition. Part 1 (Source monitoring deficits)

Phenomenological research indicates that disturbance of the basic sense of self may be a core phenotypic marker of schizophrenia spectrum disorders. Basic self-disturbance refers to disruption of the sense of ownership of experience and agency of action and is associated with a variety of anomalous subjective experiences. Little is known about the neurocognitive underpinnings of basic self-disturbance. In these two theoretical papers (of which this is Part 1), we review some recent phenomenological and neurocognitive research and point to a convergence of these approaches around the concept of self-disturbance. Specifically, we propose that subjective anomalies associated with basic self-disturbance may be associated with: 1. source monitoring deficits, which may contribute particularly to disturbances of "ownership" and "mineness" (the phenomenological notion of presence or self-affection) and 2. aberrant salience, and associated disturbances of memory, prediction and attention processes, which may contribute to hyper-reflexivity, disturbed "grip" or "hold" on the perceptual and conceptual field, and disturbances of intuitive social understanding ("common sense"). In this paper (Part 1) we focus on source monitoring deficits. Part 2 (this issue) addresses aberrant salience. Empirical studies are required in a variety of populations in order to test these proposed associations between phenomenological and neurocognitive aspects of self-disturbance in schizophrenia. An integration of findings across the phenomenological and neurocognitive "levels" would represent a significant advance in the understanding of schizophrenia and possibly enhance early identification and intervention strategies.

Would CLSI M53-A have helped in the diagnosis of HIV in Canada? Results of the performance of Canadian laboratories participating in a recent NLHRS proficiency testing panel containing HIV-1 antigen positive (antibody negative) and HIV-2 samples

INTRODUCTION

The Clinical and Laboratory Standards Institute recently published M53-A, Criteria for Laboratory Testing and Diagnosis of Human Immunodeficiency Virus (HIV) Infection; Approved Guideline (2011), which includes a state of the art algorithm for identifying HIV-1 acute and HIV-2 infections. To assess the ability of Canadian laboratories to detect these sample types and the impact of M53-A, the National Laboratory for HIV Reference Services distributed a special proficiency testing panel.

METHODS

HIVS425-2012Nov22 was sent to 42 laboratories across Canada. It contained one HIV negative sample (B), two HIV-1 positive samples (A and E), one HIV-2 positive sample (C) and one HIV-1/2 antibody negative-HIV-1 antigen positive sample (D). Data was collected and analyzed using DigitalPT; a standardized on-line tool.

RESULTS

Forty-one laboratories returned results. Sample B (HIV negative) was identified by 95% of laboratories (39/41) and samples A and E (HIV-1 positive) by 98% (40/41). No laboratory identified sample C as HIV-2 positive, although 85% (35/41) detected reactivity prompting a referral for further testing. The remaining laboratories identified sample C as HIV-1 positive (4), indeterminate (1) or gave no final status (1). Sample D (HIV antibody negative-antigen positive) was correctly identified by two laboratories as HIV-1 antigen positive while 78% (32/41) detected reactivity, recommending further testing. One laboratory did not provide a final status. Alarmingly, six laboratories called this sample HIV negative.

CONCLUSION

Although there is a high quality of HIV testing across Canada, introduction of the M53-A guideline would further improve the ability of laboratories to diagnose HIV-1 acute and HIV-2 infection.

Use of the embedded peritoneal dialysis catheter: Experience and results from a North American Center

Since 2000, the Ottawa Hospital Home Dialysis Program has used a variation on the embedded peritoneal dialysis catheter technique described by Moncrief et al. In this paper, we describe our approach to placement of peritoneal access and report our experience with 304 embedded catheters placed between January 2000 and December 2003. We review the advantages and disadvantages of this technique and describe factors that have been important to the success of our program.

Adsorption States and Modifier−Substrate Interactions on Pt(111) Relevant to the Enantioselective Hydrogenation of Alkyl Pyruvates in the Orito Reaction

Reflectance FTIR spectroscopy (RAIRS) was used to study the chemisorption and intermolecular interactions of methyl pyruvate and (+/-)-1-(1-naphthyl)ethylamine (NEA) on Pt(111). NEA serves, in this study, as a tractable model of a chiral modifier in the asymmetric hydrogenation of alpha-dicarbonyls on alkaloid-modified platinum surfaces-the Orito reaction. The results show the presence of a majority enediolate state on the clean surface. A perpendicularly adsorbed trans conformation state is populated at close to full-monolayer coverage on the clean surface. The latter state desorbs at 185 K. The enediolate undergoes dissociation at 230 K. NEA displays hydrogen-bond association at high coverages. Coadsorption studies show that NEA inhibits the formation of the enediolate state. Multilayer methyl pyruvate shows a clear hydrogen-bond interaction with chemisorbed NEA, leading to a reorientation of the ethylamine group. The high-coverage trans-chemisorbed methyl pyruvate state also hydrogen-bonds to chemisorbed NEA. The latter interaction renders the trans state stable to above 300 K. A new schematic mechanism for the Orito reaction is proposed on the basis of these data.

School absenteeism, parental work loss, and acceptance of childhood influenza vaccination

BACKGROUND

Influenza causes school absenteeism and may cause parents to miss work to care for sick children. However, it is not known whether these factors influence parental acceptance of childhood vaccination.

METHODS

A survey was mailed to parents of 1,805 children attending 3 elementary schools. It included questions about school absenteeism and employment status for adults who stayed home to care for an ill child. Parents were asked if they would consider vaccinating their child against a common wintertime respiratory virus.

RESULTS

Of the 972 surveys returned (54% return rate), 954 could be analyzed. Only 13% of respondents stated that they would not consider vaccination for their child. Sixty-nine percent of children had been absent from school because of a nonasthma respiratory illness, with an average of 2.54 days missed per child. Among respondents whose child had missed any school, 33% would definitely consider vaccination compared with 24% of respondents whose child had not missed school (P < 0.01). As children missed more school days, vaccine acceptance increased. In 53% of families, an adult had to miss work to care for the ill child. Vaccine acceptance was higher if an adult caretaker had to lose time from work because of a child's illness (35% versus 25% for non-working caretakers, P < 0.01).

CONCLUSION

Vaccine acceptance was closely linked with the amount of absenteeism caused by respiratory illness in the previous year. Parents who had to miss work to care for an ill child were more accepting of the vaccine than were other parents.

A hyperphosphorylated form of RNA polymerase II is the major interphase antigen of the phosphoprotein antibody MPM-2 and interacts with the peptidyl-prolyl isomerase Pin1

The monoclonal antibody MPM-2 recognizes a subset of M phase phosphoproteins in a phosphorylation-dependent manner. It is believed that phosphorylation at MPM-2 antigenic sites could regulate mitotic events since most of the MPM-2 antigens identified to date have M phase functions. In addition, many of these proteins are substrates of the mitotic regulator Pin1, a peptidyl-prolyl isomerase which is present throughout the cell cycle and which is thought to alter its mitotic targets by changing their conformation. In interphase cells, most MPM-2 reactivity is confined to nuclear speckles. We report here that a hyperphosphorylated form of the RNA polymerase II largest subunit is the major MPM-2 interphase antigen. These findings were made possible by the availability of another monoclonal antibody, CC-3, that was previously used to identify a 255 kDa nuclear matrix protein associated with spliceosomal components as a hyperphosphorylated form of the RNA polymerase II largest subunit. MPM-2 recognizes a phosphoepitope of the large subunit that becomes hyperphosphorylated upon heat shock in contrast to the phosphoepitope defined by CC-3, whose reactivity is diminished by the heat treatment. Therefore, these two antibodies may discriminate between distinct functional forms of RNA polymerase II. We also show that RNA polymerase II large subunit interacts with Pin1 in HeLa cells. Pin1 may thus regulate transcriptional and post-transcriptional events by catalyzing phosphorylation-dependent conformational changes of the large RNA polymerase II subunit.

Potential cost savings attributable to influenza vaccination of school-aged children

OBJECTIVE

To analyze the costs and benefits of influenza vaccination of healthy school-aged children.

DESIGN

The analysis was based on data from the literature. Total costs included direct medical costs for vaccination, physician visits, and treatment as well as indirect costs. Indirect costs were in the form of lost productivity when working parents stayed home to care for ill children or to take children to an office for vaccination. The total costs of vaccination strategies were compared with the total cost of not vaccinating. For the base case, the vaccine was assumed to have no effect on rates of otitis media.

SETTING

Two hypothetical scenarios were investigated 1) individual-initiated vaccination and 2) vaccination in a group-based setting. The former scenario required the child to be accompanied to a clinic by a parent during usual work hours.

RESULTS

Vaccination resulted in a net savings per child vaccinated of $4 for individual-initiated vaccination and of $35 for group-based vaccination. The savings were caused primarily by averted indirect costs. Moderate increases in the cost of vaccination or reductions in the rate of influenza would eliminate the savings for individual-initiated vaccination but not for group-based vaccination. Alternatively, if influenza vaccination was effective in reducing rates of otitis media, the net savings from vaccination would be substantially higher than the base case.

CONCLUSION

Vaccination of school-aged children against influenza could have substantial financial benefits to society, especially if performed in a group-based setting. influenza, cost-effectiveness, vaccination, children, cost.

Interfacing the radiology information system to the modality: an integrated approach

The radiology information system (RIS) provides patient and examination information that is used in setting up and performing a radiologic procedure. In a digital imaging environment, information from the RIS can also be used to populate fields in the Digital Imaging and Communications in Medicine (DICOM) image header. Ideally, information from the RIS should be available at the modality at the time of the examination, and automatically be attached to the image in the appropriate DICOM fields before storage in the picture archiving and communications system (PACS). We have designed a highly integrated RIS interface for a digital radiography (DR) system. This interface employs browser technology to make RIS information conveniently available at the modality, and DICOM modality performed procedure step (MPPS) for RIS/DR information exchange. A novel feature of our approach is that a single display screen at the modality is used to alternatively display either the modality control window or the RIS window. Full access to RIS capabilities is available at the modality, including worklists and prior reports.

Effects of red nucleus microstimulation on the locomotor pattern and timing in the intact cat: a comparison with the motor cortex

Effects of red nucleus microstimulation on the locomotor pattern and timing in the intact cat: a comparison with the motor cortex. To determine the extent to which the rubrospinal tract is capable of modifying locomotion in the intact cat, we applied microstimulation (cathodal current, 330 Hz; pulse duration 0.2 ms; maximal current, 25 microA) to the red nucleus during locomotion. The stimuli were applied either as short trains (33 ms) of impulses to determine the capacity of the rubrospinal tract to modify the level of electromyographic (EMG) activity in different flexors and extensors at different phases of the step cycle or as long trains (200 ms) of pulses to determine the effect of the red nucleus on cycle timing. Stimuli were also applied with the cat at rest (33-ms train). This latter stimulation evoked short-latency (average = 11.8-19.0 ms) facilitatory responses in all of the physiological flexor muscles of the forelimb that were recorded; facilitatory responses were also common in the elbow extensor, lateral head of triceps but were rare in the physiological wrist and digit extensor, palmaris longus. Responses were still evoked in most muscles when the current was decreased to near threshold (3-10 microA). Stimulation during locomotion with the short trains of stimuli evoked shorter-latency (average = 6.0-12.5 ms) facilitatory responses in flexor muscles during the swing phase of locomotion and, except in the case of the extensor digitorum communis, evoked substantially smaller responses in stance. The same stimuli also evoked facilitatory responses in the extensor muscles during swing and produced more complex effects involving both facilitation and suppression in stance. Increasing the duration of the train to 200 ms modified the amplitude and duration of the EMG activity of both flexors and extensors but had little significant effect on the cycle duration. In contrast, whereas stimulation of the motor cortex with short trains of stimuli during locomotion had very similar effects to that of the red nucleus, increasing the train duration to 200 ms frequently produced a marked reset of the step cycle by curtailing stance and initiating a new period of swing. The results suggest that whereas both the motor cortex and the red nucleus have access to the interneuronal circuits responsible for controlling the structure of the EMG activity in the step cycle, only the motor cortex has access to the circuits responsible for controlling cycle timing.

Kinetic and energetic patterns for hindlimb obstacle avoidance during cat locomotion

The safe control of walking over different terrains requires appropriate adaptations in the dynamic and kinematic limb patterns. To date, the study of locomotor dynamics in the cat has been confined to level, unobstructed walking. The present study extends the work of Lavoie et al. by applying linked segment analyses to estimate muscle contributions to torque and mechanical power at the hindlimb joints of two female cats during both unobstructed walking and obstacle avoidance. Data during obstacle avoidance were analyzed both when the hindlimb led in clearance and was farthest from the obstacle, and when it trailed in clearance and was closest or near to the obstacle. It was found that, in both the Far and Near obstructed conditions, the cats cleared the obstacles primarily by increasing the knee flexor torque already used during unobstructed gait. Contributions from the hip and ankle muscle groups were more variable. There was more emphasis on the hip extensors in mid to late stance, and the hip flexors generated a small amount of energy at paw-lift in the Far condition. In the Near condition, the hip extensors were employed to control hip flexion. We suggest that hip flexor generation power in mid-swing contributes to the clearance of the upcoming obstacle in the Far condition while, in the Near condition, hip flexion advances the already extended limb ahead of the obstacle. The ankle was actively dorsiflexed in the Near condition but was maintained in extension in the Far condition. The emphasis on active knee flexor control by the cat to avoid obstacles, as well as the dependence of ankle control on obstacle proximity, is similar to strategies seen for humans. However, the knee flexor strategy is innate to the cat's normal level walking control, whereas in humans active knee flexion at toe-off requires a reorganization from level, non-obstructed gait.

The nuclear matrix protein p255 is a highly phosphorylated form of RNA polymerase II largest subunit which associates with spliceosomes

The monoclonal antibody CC-3 recognizes a phosphodependent epitope on a 255 kDa nuclear matrix protein (p255) recently shown to associate with splicing complexes as part of the [U4/U6.U5] tri-snRNP particle [Chabot et al. (1995) Nucleic Acids Res. 23, 3206-3213]. In mouse and Drosophila cultured cells the electrophoretic mobility of p255, faster in the latter species, was identical to that of the hyperphosphorylated form of RNA polymerase II largest subunit (IIo). The CC-3 immunoreactivity of p255 was abolished by 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole, which is known to cause the dephosphorylation of the C-terminal domain of subunit IIo by inhibiting the TFIIH-associated kinase. The identity of p255 was confirmed by showing that CC-3-immunoprecipitated p255 was recognized by POL3/3 and 8WG16, two antibodies specific to RNA polymerase II largest subunit. Lastly, the recovery of RNA polymerase II largest subunit from HeLa splicing mixtures was compromised by EDTA, which prevents the interaction of p255 with splicing complexes and inhibits splicing. Our results indicate that p255 represents a highly phosphorylated form of RNA polymerase II largest subunit physically associated with spliceosomes and possibly involved in coupling transcription to RNA processing.

Role of the motor cortex in the control of visually triggered gait modifications

One important aspect of locomotor control is the ability of an animal to make anticipatory gait modifications to avoid obstacles, by stepping either around them or over them. This paper reviews some of the evidence that suggests that the motor cortex is one of the principal structures involved in the control of such anticipatory gait modifications in cats, in particular when they are triggered by a visual signal. Evidence for this statement is provided both from experiments in which the motor cortex has been lesioned or inactivated and from studies in which the activity of motor cortical neurones has been recorded during locomotor tasks in which visual information is required to ensure the correct positioning of the paw or an appropriate modification of the limb trajectory. Inactivation of small regions of the motor cortex with the GABA agonist muscimol results in changes in the limb trajectory so that cats hit an obstacle instead of stepping over it as they do normally. A similar disruption of the hindlimb trajectory is seen following lesions of the spinal cord at T13 that interrupt the corticospinal tract. The results from cell recording studies are complementary in that they show that the activity of many identified pyramidal tract neurones increases when the cat is required to modify the forelimb or hindlimb trajectory to step over obstacles. We suggest that the major function of this increased discharge frequency is to regulate the amplitude, duration, and temporal pattern of muscle activity during the gait modification to ensure an appropriate modification of limb trajectory. We further suggest that different groups of pyramidal tract neurones are involved in regulating the activity of groups of synergistic muscles active at different times in the gait modification. For example, some groups of pyramidal tract neurones would be involved in ensuring the appropriate and sequential activation of the muscle groups involved in the initial flexion of the elbow, while others would be active prior to the repositioning of the paw on the support surface. We discuss the possibility that the motor cortical activity seen during locomotion is the sum result of a feedforward signal, which provides visuospatial information about the environment, and feedback activity, which signals, in part, the state of the interneuronal pattern generating networks in the spinal cord. The way in which the resulting descending command may interact with the basic locomotor rhythm to produce the gait modifications is discussed.

A kinematic and kinetic analysis of locomotion during voluntary gait modification in the cat

As part of a study to characterize the postural reactions that occur during voluntary gait modification, we examined the kinematic, electromyographic (EMG), and kinetic responses that occurred when cats stepped over an obstacle placed in their path. Analyses of the kinematics as each of the forelimbs stepped over the obstacle showed that changes in joint angles were most pronounced at the elbow of the first (lead) limb, and at the shoulder of the second (trailing) limb. In the hindlimbs, there was a pronounced change in the knee joint angle in both the leading and trailing limbs. Examination of the horizontal and vertical velocities of the tip of the forepaw suggests that the movements can be divided into two phases: one in which the limb is rapidly lifted above and over the obstacle, and a slower one during which the limb is carefully repositioned on the floor. On the basis of the velocity profiles, we suggest that the repositioning of the paw on the support surface is more critically controlled for the forelimb than for the hindlimb. Analysis of the changes in the ground reaction forces in the supporting limbs during these gait modifications showed that there were two major increases in vertical reaction force. One of these occurred as the two forelimbs were straddling the obstacle, the other when the two hindlimbs were straddling it. There was also a net increase in the anteroposterior force that resulted in a small increase in propulsion as the cat stepped over the obstacle. Each change in the vertical ground reaction force was paralleled by a similar change in the amplitude of the EMG recorded from the respective extensor muscles. An analysis of the vertical displacement of the scapula and of the pelvis showed that there was a slight increase in the height of the scapula in the support limb just prior to and during the swing phase of the trailing forelimb, and a more pronounced and progressive change in the height of the pelvis prior to and during the passage of both hindlimbs over the obstacle. We suggest that the increases in vertical ground reaction force raise the height of the body sufficiently to allow, respectively, passage of the trail forelimb and each of the hindlimbs over the obstacle. The results are discussed with respect to both the biomechanical changes underlying these gait modifications and the neuronal mechanisms implicated in their control.

A controlled trial of cyclosporine in patients with progressive membranous nephropathy. Canadian Glomerulonephritis Study Group

A controlled trial of cyclosporine in patients diagnosed with progressive membranous nephropathy (MGN) was carried out to determine whether cyclosporine (D) would be more effective than placebo (P) in reducing the rate of deterioration in renal function. Patients (N = 64) with MGN were placed on a restricted protein diet (< or = 0.9 g/kg) and followed closely for 12 months (Part 1). Patients at high risk of progression based on an absolute loss in creatinine clearance (CCr) of > or = 8 ml/min and persistent nephrotic range proteinuria (Pr) were selected and randomly assigned to either (D) (N = 9) or (P) (N = 8) for 12 months (Part 2). No differences in the two groups were noted at entry. After 12 months, the improvement in CCr slope in ml/min/month was significantly greater in the D patients (D + 2.1 vs. P + 0.5, mean difference 1.6; 95% CI 0.3 to 3.0, P < 0.02). This improvement was maintained in six of eight D (75%) over a mean follow-up period of 21 months. Daily Pr also improved with D (by month 3, D - 4.5 g/day vs. P + 0.7 g/day, P = 0.02) and was sustained in six of eight (75%) D patients. When Pr was expressed as a function of their concurrent CCr, the D versus P patients' time to halving was faster (P = 0.02) and absolute number higher (4/9 D vs 0/8 P). In the D group a trend towards worse hypertension and an increase in the number of transient rises in serum creatinine were noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Flucytosine dosing in an obese patient with extrameningeal cryptococcal infection

A 31-year-old, obese woman with extrameningeal cryptococcal disease was admitted to the Medical College of Virginia for antifungal therapy. Various physiologic variables influence flucytosine pharmacokinetics, and there are no guidelines for dosing the agent in obese patients. This patient received a dosage based on her ideal body weight, and serum drug concentrations were monitored. She recovered without sequelae.

Inferior constrictor myotomy in oculopharyngeal muscular dystrophy: clinical and manometric evaluation

Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant transmitted condition seen mainly in the French Canadian population. Twenty-one patients with an established diagnosis of this rare disease underwent inferior constrictor myotomy. All patients were evaluated clinically and 12 of them underwent pharyngoesophageal manometric evaluation both preoperatively and postoperatively. All patients presented with severe oropharyngeal dysphagia and frequent aspiration together with pharyngooral and pharyngonasal regurgitation. Our results showed that all symptoms were significantly improved after inferior constrictor myotomy. Manometric assessment showed significant differences in pressure, duration and frequency of pharyngeal contraction when compared with a control group. After surgery pharyngeal contraction frequency was significantly lowered toward the normal level but other parameters of pharyngeal function remained unchanged. At the level of the upper esophageal sphincter, resting and closing pressure, relaxation time, relaxation and coordination were studied. There was no significant difference between control subjects and OPMD patients for these variables. Surgery significantly lowered the resting and closing pressure of the sphincter but did not modify significantly the other parameters.

Radionuclide esophageal transit in progressive systemic sclerosis

Twenty-three patients with progressive systemic sclerosis (PSS) were studied by radionuclide esophageal transit (RT) and esophageal manometry. Twenty-two patients had abnormal manometry ranging from lower esophageal sphincter incompetence to aperistaltism. Of these 22 patients, twenty (91%) had abnormal RT with prolongation of transit time. A characteristic RT pattern showing stagnation of the radionuclide in the distal and middle segments of the esophagus was demonstrated in 82% of the patients with advanced sclerodermatous involvement of the esophagus. Fifteen of the 19 controls (79%) studied had a normal RT. Four showed prolongation of transit time without stagnation. We conclude that RT is a safe, noninvasive, highly sensitive method which might be used as an alternative to esophageal manometry. However, it may lack specificity.

Regulatory proteins for the activated third and fourth components of complement (C3b and C4b) in mice. II. Identification and properties of complement receptor type 1 (CR1)

We identified on the membrane of mouse spleen cells a polypeptide of Mr 190,000 (S190), with binding affinity for the mouse third component of the complement system (C3). S190, purified by affinity chromatography on C3-Sepharose, has properties resembling those of the human C3 receptor type 1 (CR1). Thus, S190, like CR1, served as a cofactor for the C3b inactivator (I)-mediated cleavage of fluid-phase C3b into iC3b, and had cofactor activity comparable to that of serum factor H (H). S190 also acted as a cofactor for the cleavages of membrane-bound C3b or membrane-bound iC3b into C3c (Mr 140,000) and C3dg (Mr 40,000) by serum factor I. As is the case with CR1, the specific activity of S190 for the cleavages leading to C3c-C3dg formation was approximately 100-fold greater than that of H. We therefore conclude that S190 and CR1 are analogous proteins.

Regulatory proteins for the activated third and fourth components of complement (C3b and C4b) in mice. II. Identification and properties of complement receptor type 1 (CR1)

We identified on the membrane of mouse spleen cells a polypeptide of Mr 190,000 (S190), with binding affinity for the mouse third component of the complement system (C3). S190, purified by affinity chromatography on C3-Sepharose, has properties resembling those of the human C3 receptor type 1 (CR1). Thus, S190, like CR1, served as a cofactor for the C3b inactivator (I)-mediated cleavage of fluid-phase C3b into iC3b, and had cofactor activity comparable to that of serum factor H (H). S190 also acted as a cofactor for the cleavages of membrane-bound C3b or membrane-bound iC3b into C3c (Mr 140,000) and C3dg (Mr 40,000) by serum factor I. As is the case with CR1, the specific activity of S190 for the cleavages leading to C3c-C3dg formation was approximately 100-fold greater than that of H. We therefore conclude that S190 and CR1 are analogous proteins.