Conformational control of Cas9 by CRISPR hybrid RNA-DNA guides mitigates off-target activity in T cells.

The off-target activity of the CRISPR-associated nuclease Cas9 is a potential concern for therapeutic genome editing applications. Although high-fidelity Cas9 variants have been engineered, they exhibit varying efficiencies and have residual off-target effects, limiting their applicability. Here, we show that CRISPR hybrid RNA-DNA (chRDNA) guides provide an effective approach to increase Cas9 specificity while preserving on-target editing activity. Across multiple genomic targets in primary human T cells, we show that 2'-deoxynucleotide (dnt) positioning affects guide activity and specificity in a target-dependent manner and that this can be used to engineer chRDNA guides with substantially reduced off-target effects. Crystal structures of DNA-bound Cas9-chRDNA complexes reveal distorted guide-target duplex geometry and allosteric modulation of Cas9 conformation. These structural effects increase specificity by perturbing DNA hybridization and modulating Cas9 activation kinetics to disfavor binding and cleavage of off-target substrates. Overall, these results pave the way for utilizing customized chRDNAs in clinical applications.

Allogeneic chimeric antigen receptor-T cells with CRISPR-disrupted programmed death-1 checkpoint exhibit enhanced functional fitness.

BACKGROUND AIMS: Therapeutic disruption of immune checkpoints has significantly advanced the armamentarium of approaches for treating cancer. The prominent role of the programmed death-1 (PD-1)/programmed death ligand-1 axis for downregulating T cell function offers a tractable strategy for enhancing the disease-modifying impact of CAR-T cell therapy. METHODS: To address checkpoint interference, primary human T cells were genome edited with a next-generation CRISPR-based platform (Cas9 chRDNA) by knockout of the PDCD1 gene encoding the PD-1 receptor. Site-specific insertion of a chimeric antigen receptor specific for CD19 into the T cell receptor alpha constant locus was implemented to drive cytotoxic activity. RESULTS: These allogeneic CAR-T cells (CB-010) promoted longer survival of mice in a well-established orthotopic tumor xenograft model of a B cell malignancy compared with identically engineered CAR-T cells without a PDCD1 knockout. The persistence kinetics of CB-010 cells in hematologic tissues versus CAR-T cells without PDCD1 disruption were similar, suggesting the robust initial debulking of established tumor xenografts was due to enhanced functional fitness. By single-cell RNA-Seq analyses, CB-010 cells, when compared with identically engineered CAR-T cells without a PDCD1 knockout, exhibited fewer Treg cells, lower exhaustion phenotypes and reduced dysfunction signatures and had higher activation, glycolytic and oxidative phosphorylation signatures. Further, an enhancement of mitochondrial metabolic fitness was observed, including increased respiratory capacity, a hallmark of less differentiated T cells. CONCLUSIONS: Genomic PD-1 checkpoint disruption in the context of allogeneic CAR-T cell therapy may provide a compelling option for treating B lymphoid malignancies.

Mapping the genomic landscape of CRISPR-Cas9 cleavage.

RNA-guided CRISPR-Cas9 endonucleases are widely used for genome engineering, but our understanding of Cas9 specificity remains incomplete. Here, we developed a biochemical method (SITE-Seq), using Cas9 programmed with single-guide RNAs (sgRNAs), to identify the sequence of cut sites within genomic DNA. Cells edited with the same Cas9-sgRNA complexes are then assayed for mutations at each cut site using amplicon sequencing. We used SITE-Seq to examine Cas9 specificity with sgRNAs targeting the human genome. The number of sites identified depended on sgRNA sequence and nuclease concentration. Sites identified at lower concentrations showed a higher propensity for off-target mutations in cells. The list of off-target sites showing activity in cells was influenced by sgRNP delivery, cell type and duration of exposure to the nuclease. Collectively, our results underscore the utility of combining comprehensive biochemical identification of off-target sites with independent cell-based measurements of activity at those sites when assessing nuclease activity and specificity.

Evaluation of the influence exerted by different dental specialty backgrounds and measuring instrument reproducibility on esthetic aspects of maxillary implant-supported single crown.

OBJECTIVE: To evaluate the influence exerted by different dental specialty backgrounds as well as the validity and reproducibility of the Pink Esthetic Score/White Esthetic Score (PES/WES) and the modified Implant Crown Aesthetic Index (mod-ICAI) on the assessment of esthetic aspects of maxillary implants supported single-tooth prosthesis. MATERIAL AND METHODS: A total of fourteen examiners (Two orthodontists, two prosthodontists, two oral surgeons, two periodontists, two dental technicians, two dental assistants, and two postgraduate students in Implant Dentistry evaluated 20 photographs of single-implant-supported crowns and five photographs of unrestored teeth of esthetic zone in a two part study. The examiners assessed the photographs with each index (Pink Esthetic Score/White Esthetic Score and modified Implant Crown Aesthetic Index), twice with a week's interval. Orders of photographs were rearranged in the second assessment. RESULTS: Kruskal-Wallis test results showed significant differences among all the six specialties (P ≤ 0.001). DAs and periodontists had significantly better ratings than other specialties with both indices. Prosthodontists had the lowest mean rank scores regardless of the index. Interobserver agreement was also lowest between the two prosthodontists (4-28%), rest of the groups had low-to-moderate agreement (20-80%) when limited allowance was accepted. With mod-ICAI, more interobserver agreement was noted within the specialty group than with PES/WES. CONCLUSIONS: The PES/WES and the modified ICAI can be reliable estimates of esthetic outcomes. The assessor degree of specialization affected the esthetic evaluation with both the PES/WES and the modified ICAI. DAs and periodontists were identified to provide more favorable ratings than other specialties while prosthodontists were most critical in this study. With modified ICAI, more interobserver agreement within specialty resulted. The interexaminer agreement may be increased if more tolerance of 1-2 points is considered.

Feasibility, tolerability, and first experience of intracystic treatment with peginterferon alfa-2a in patients with cystic craniopharyngioma.

Background: Children with craniopharyngiomas (CPs) typically suffer from a life-long chronic disease. The younger the child, the more vulnerable the maturing brain is to invasive therapies such as surgery or radiotherapy. Therefore, treatment modalities facilitating avoidance or delay of invasive therapies are beneficial for these patients. In the last decade, intracystic injection of interferon alfa-2a or alfa-2b evolved as a treatment of choice based on efficacy and minor toxicity. However, the drug is no longer available internationally. After an extensive pharmacological review, peginterferon alfa-2a was identified as the agent with closest similarity. Methods: A retrospective case series is described, including five patients treated with intracystic peginterferon alfa-2a for cystic CP according to an innovative care protocol. After initial CP cyst aspiration, peginterferon alfa-2a was injected once per week via an Ommaya reservoir for 6 weeks followed by response assessment with MRI. Results: Patients' age ranged from 4 to 54 years (four patients <12 years, one adult patient). Intracystic therapy with peginterferon alfa-2a was tolerated well by all five individuals without any major toxicities and resulted in cyst shrinkage in all of the five patients. The importance of a permeability study prior to commencing intracystic therapy became apparent in one patient who suffered from cyst leakage. Conclusions: Intracystic treatment with peginterferon alfa-2a was found to be a tolerable and efficacious treatment modality in patients with cystic CP. This experience warrants further research with a larger number of patients with measurement of long-term efficacy and safety outcomes.

Differentiation of opioid drug effects by hierarchical multi-site phosphorylation.

Differences in the ability of opioid drugs to promote regulated endocytosis of µ-opioid receptors are related to their tendency to produce drug tolerance and dependence. Here we show that drug-specific differences in receptor internalization are determined by a conserved, 10-residue sequence in the receptor's carboxyl-terminal cytoplasmic tail. Diverse opioids induce receptor phosphorylation at serine (S)375, present in the middle of this sequence, but opioids differ markedly in their ability to drive higher-order phosphorylation on flanking residues [threonine (T)370, T376, and T379]. Multi-phosphorylation is required for the endocytosis-promoting activity of this sequence and occurs both sequentially and hierarchically, with S375 representing the initiating site. Higher-order phosphorylation involving T370, T376, and T379 specifically requires GRK2/3 isoforms, and the same sequence controls opioid receptor internalization in neurons. These results reveal a biochemical mechanism differentiating the endocytic activity of opioid drugs.

Methylnaltrexone for opioid-induced constipation in pediatric oncology patients.

BACKGROUND: Pediatric oncology patients can experience opioid-induced constipation, which may not respond to laxative treatment. Methylnaltrexone is an opioid receptor antagonist that can reverse opioid-induced constipation without affecting analgesia. Published literature on the use of methylnaltrexone in children is very limited. This retrospective review describes the effectiveness and safety of methylnaltrexone for opioid-induced constipation in pediatric oncology patients. PROCEDURE: A retrospective review of health records was conducted for pediatric oncology in-patients who were prescribed methylnaltrexone between May 2008 and September 2012 at The Hospital for Sick Children. Demographic, clinical, efficacy, and safety data were collected, including; opioid, laxative, and methylnatrexone dosing and frequency. RESULTS: Fifteen patients (median age: 14 years, range: 4-17 years) received methylnaltrexone; 12 received a single dose while three received multiple doses. At the time of methylnaltrexone administration, patients were receiving a median oral morphine dose equivalent of 5.7 mg/kg/day (range: 1.5-29.2 mg/kg/day) and had not had any bowel movements for several days despite treatment with multiple laxatives. Methylnaltrexone was given at a mean dose of 0.15 ± 0.02 mg/kg/dose (range: 3-12 mg/dose) as a subcutaneous injection. After 14 of 19 doses administered, patients had a bowel movement within 4 hours. Three patients had documented mild gastrointestinal upset following methylnaltrexone administration. None reported a reduction of pain control or opioid withdrawal symptoms. CONCLUSION: This case series suggests that methylnaltrexone is safe and may be effective when given subcutaneously as a 0.15 mg/kg single dose to pediatric oncology patients with opioid-induced constipation.

Point prevalence survey of antimicrobial utilization in the cardiac and pediatric critical care unit.

OBJECTIVES: To determine the rate of documented infections and prevalence of antimicrobial use among pediatric patients admitted to the PICU. To assess the appropriateness of antimicrobial prescribing according to clinical and microbiological findings, Infectious Disease Consult recommendations, and formulary guidelines. DESIGN: Prospective point prevalence study. SETTING: Cardiac and medical-surgical critical care units (CCCU-PICU) in a tertiary care pediatric teaching hospital in Toronto, Canada. PATIENTS: All patients admitted to the CCCU-PICU during the week of October 27, 2008 (period A) and February 9, 2009 (period B) were followed until completion of their antimicrobial course(s). Data were collected on infection types and indications, frequency, and types of antimicrobials used. Appropriateness of antimicrobial prescribing was assessed according to predefined criteria by four blinded clinician assessors. MEASUREMENT AND MAIN RESULTS: Forty-two of 60 patients (70%) received antimicrobials in period A and 42 of 53 patients (79%) received antimicrobials in period B. Of the patients on antimicrobials, 45% in period A and 52% in period B had a definitive diagnosis of infection. Pneumonia and sepsis were the most common infections in period A, whereas pneumonia and other respiratory tract infections were the most common in period B. Antimicrobials were commonly prescribed for documented infection (38%) during period A and empiric therapy (47%) during period B. Cefazolin, cefuroxime, vancomycin, and gentamicin were the commonly used antimicrobials during both periods. Inappropriate antimicrobial use ranged from 16.7% to 61.9%, depending on assessors and surveillance period. The most common reasons for inappropriate use were overly broad spectrum, wrong dosage, and unwarranted overlap of spectrum. CONCLUSIONS: There was a high prevalence of antimicrobial use in CCCU-PICU patients. Because a significant proportion of antimicrobial use was deemed inappropriate, interventions are required to optimize antimicrobial use in critically ill children.

Recovery from mu-opioid receptor desensitization after chronic treatment with morphine and methadone.

Chronic treatment with morphine results in a decrease in µ-opioid receptor sensitivity, an increase in acute desensitization, and a reduction in the recovery from acute desensitization in locus ceruleus neurons. With acute administration, morphine is unlike many other opioid agonists in that it does not mediate robust acute desensitization or induce receptor trafficking. This study compares µ-opioid receptor desensitization and trafficking in brain slices taken from rats treated for 6-7 d with a range of doses of morphine (60, 30, and 15 mg · kg(-1) · d(-1)) and methadone (60, 30, and 5 mg · kg(-1) · d(-1)) applied by subcutaneous implantation of osmotic minipumps. Mice were treated with 45 mg · kg(-1) · d(-1). In morphine-treated animals, recovery from acute [Met](5)enkephalin-induced desensitization and receptor recycling was diminished. In contrast, recovery and recycling were unchanged in slices from methadone-treated animals. Remarkably the reduced recovery from desensitization and receptor recycling found in slices from morphine-treated animals were not observed in animals lacking ß-arrestin-2. Furthermore, pharmacological inhibition of G-protein receptor kinase 2 (GRK2), although not affecting the ability of [Met](5)enkephalin to induce desensitization, acutely reversed the delay in recovery from desensitization produced by chronic morphine treatment. These results characterize a previously unidentified function of the GRK/arrestin system in mediating opioid regulation in response to chronic morphine administration. They also suggest that the GRK/arrestin system, rather than serving as a primary mediator of acute desensitization, controls recovery from desensitization by regulating receptor reinsertion to the plasma membrane after chronic treatment with morphine. The sustained GRK/arrestin-dependent desensitization is another way in which morphine and methadone are distinguished.

Desensitization and trafficking of µ-opioid receptors in locus ceruleus neurons: modulation by kinases.

The phosphorylation of µ-opioid receptors (MOPRs) by G protein-coupled receptor kinases (GRKs), followed by arrestin binding, is thought to be a key pathway leading to desensitization and internalization. The present study used the combination of intracellular and whole-cell recordings from rats and mice, as well as live cell imaging of Flag-tagged MOPRs from mouse locus ceruleus neurons, to examine the role of protein kinases in acute desensitization and receptor trafficking. Inhibition of GRKs by using heparin or GRK2-mutant mice did not block desensitization or alter the rate of recovery from desensitization. The nonselective kinase inhibitor staurosporine did not reduce the extent of [Met(5)]enkephalin (ME)-induced desensitization but increased the rate of recovery from desensitization. In the presence of staurosporine, ME-activated FlagMOPRs were internalized but did not traffic away from the plasma membrane. The increased rate of recovery from desensitization correlated with the enhancement in the recycling of receptors to the plasma membrane. ME-induced MOPR desensitization persisted and the trafficking of receptors was modified after inhibition of protein kinases. The results suggest that desensitization of MOPRs may be an early step after agonist binding that is modulated by but is not dependent on kinase activity.

Pain management in children: Part 1 - Pain assessment tools and a brief review of nonpharmacological and pharmacological treatment options.

If pain is not treated quickly and effectively in children, it can cause long-term physical and psychological sequelae. Therefore, it is important for all health care providers to understand the importance of effective pain control in children. This article is divided into 2 parts: Part 1 reviews the pharmacotherapy of pain management in children and Part 2 will review the problems relating to the use of codeine in children, and the rationale for recommending morphine as the opioid of choice in the treatment of moderate to severe pain. There has been growing concern about codeine's lack of efficacy and increased safety concerns in its use in children. Due to the variability of codeine metabolism and unpredictable effects on efficacy and safety, The Hospital for Sick Children in Toronto, Ontario, no longer includes codeine or codeine-containing products on the regular hospital formulary and now recommends oral morphine as the agent of choice for the treatment of moderate to severe pain in children. A knowledge translation (KT) strategy was developed and implemented by the hospital's Pain Task Force to support this practice change.

Is Routine Therapeutic Drug Monitoring of Anti-Retroviral Agents Warranted in Children Living with HIV?

OBJECTIVE: The utility of routine therapeutic drug monitoring (TDM) in children living with HIV has not been extensively studied. The purpose of this study was to assess this strategy. METHODS: This was a single-center, prospective observational study of routine TDM for protease inhibitors (PIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), and integrase strand transfer inhibitors (INSTIs) in children living with HIV who were receiving antiretroviral therapy (ART) between February and December 2014. Outcome measures included the proportion of serum antiretroviral (ARV) medication concentrations in the therapeutic range (target values extrapolated from adult data) and the effect of serum concentrations on virologic control, medication adherence, and toxicity. RESULTS: Forty-eight children with a median age of 13 years (interquartile range, 3-18) were included. Median viral load (VL) and CD4% were <40 copies/mL (range, <40-124) and 37.4% (range, 8.4-47.9), respectively. Adherence was considered excellent in 95.8% of patients. Of the 50 serum trough concentrations (PI n = 19 [38%]; NNRTI n = 27 [54%]; INSTI n = 4 [8%]), 66% (n = 33) were in the therapeutic range, 12% (n = 6) were subtherapeutic, and 22% (n = 11) were supratherapeutic. There was no statistically significant correlation between serum ARV concentrations and patient demographics, VL, CD4%, or adherence. No clinically significant adverse events were noted. One dose adjustment was made for a subtherapeutic serum raltegravir concentration, likely attributable to interaction with ritonavir. CONCLUSIONS: This study does not support routine TDM in healthy children living with HIV who are well controlled on antiretroviral medication regimens. A more targeted strategy, such as when adherence is questioned or when there are suspected drug interactions, may be more appropriate.

Patients' adherence to osteoporosis therapy: exploring the perceptions of postmenopausal women.

OBJECTIVE: To explore the experiences and perceptions of postmenopausal women regarding strategies to improve adherence to osteoporosis therapy. DESIGN: Qualitative, mixed phenomenologic study using focus groups. SETTING: Family physicians' and specialists' practices and community pharmacies in Hamilton, Ont. PARTICIPANTS: A total of 37 postmenopausal women currently taking at least 1 prescription or over-the-counter medication for osteoporosis. METHOD: Focus groups were conducted using a semistructured interview guide consisting of 10 open-ended questions about patients' perceptions of their osteoporosis medications, their reasons for adherence and non-adherence to therapy, and the effectiveness of strategies they had tried to improve adherence. At least 2 research team members analyzed the data to find primary themes. MAIN FINDINGS: Analysis of data from the 7 focus groups found 6 main factors that influenced adherence to medications: belief in the importance of taking medications for osteoporosis, medication-specific factors, beliefs regarding medications and health, relationships with health care providers, information exchange, and strategies to improve adherence. Strategies that facilitated adherence to medications included having a system for taking medications, using cues or reminders, being well informed about the reasons for taking medications, and having regular follow-up by health care providers for support and monitoring after having been prescribed medications. CONCLUSION: Results of this study provide a better understanding of how patients' perceptions and experiences affect their adherence to osteoporosis medications. Because each patient's reasons for non-adherence might be different, depending on individual beliefs or circumstances, strategies to improve adherence to medications should be individualized accordingly.

Patient adherence to osteoporosis medications: problems, consequences and management strategies.

Adherence to osteoporosis medications is relatively poor. Approximately 20-30% of patients taking daily or weekly treatments may suspend their treatment within 6 to 12 months of initiating therapy. Patients with poor adherence increase their risk of osteoporotic fractures and hospitalisation. The majority of patients who discontinue therapy appear to do so because of drug-induced adverse effects. Fear of adverse effects or other health risks is another commonly cited reason for discontinuing therapy. Factors associated with medication adherence include fractures, regular exercise, female sex, fewer non-osteoporosis medications and co-morbidities, early menopause, willingness to take medications, awareness of osteoporosis status based on a diagnostic test, anti-inflammatory therapy and corticosteroid therapy. Factors associated with non-adherence include adverse effects, pain and being unsure about bone mineral density (BMD) test results. Bisphosphonates, a common class of drugs for treating osteoporosis, have specific administration requirements (e.g. fasting, remaining upright and not ingesting other medications concomitantly). Patient surveys indicate that 12-18% of patients report non-compliance with at least one administration rule. Strategies to increase adherence include reducing administration frequency to weekly or monthly, monitoring patients with bone markers and BMD testing, providing adequate instructions, practitioner feedback and support, and educational materials and sessions. Future studies are needed regarding strategies to increase adherence to osteoporosis medications.

Nevirapine Pharmacokinetics and Safety in Neonates Receiving Combination Antiretroviral Therapy for Prevention of Vertical HIV Transmission.

BACKGROUND: Nevirapine (NVP)-based combination antiretroviral therapy is routinely prescribed to infants deemed at high risk of vertical HIV infection in our centers. We evaluated NVP pharmacokinetics and safety of this regimen. METHODS: Neonates were recruited prospectively between September 2012 and April 2015 or enrolled retrospectively if treated similarly before prospective study initiation. NVP was dosed at 150 mg/m daily for 14 days, then twice daily for 14 days. NVP levels were drawn at weeks 1, 2, and 4 [target trough (NVP-T): 3-8 mg/L]. RESULTS: Thirty-three neonates were included (23 prospectively). Median gestational age (GA) and birth weight were 38 weeks (32-41 weeks) and 2.9 kg (1.5-4.2 kg), respectively. Median NVP-Ts were 8.2 mg/L (1.6-25.1 mg/L), 3.5 mg/L (1.6-6.8 mg/L), and 4.3 mg/L (0.1-19.9 mg/L) at weeks 1, 2, and 4, respectively. The proportions with therapeutic NVP-T were 42%, 61%, and 73% at these same timepoints. Median apparent oral clearance (CL/F) increased from 0.05 L·kg·h (0.01-0.50 L·kg·h) at week 2 to 0.18 L·kg·h (0.01-0.78 L·kg·h) at week 4. Increased drug exposure [area under the curve (AUCτ)] correlated with younger GA (r = 0.459, P = 0.032) and lower birth weight (r = 0.542, P = 0.009). The most common adverse events potentially attributable to combination antiretroviral therapy were transient asymptomatic hyperlactatemia (26%), anemia (24.7%), and neutropenia (22.1%). CONCLUSIONS: Treatment dose NVP was generally well-tolerated and associated with normalization of trough levels over time in most cases without dose adjustment. Lower empiric dosing is recommended for infants <34 weeks of GA. Routine therapeutic drug monitoring may not be required for infants ≥34 weeks of GA.

Domperidone-Associated QT Interval Prolongation in Non-oncologic Pediatric Patients: A Review of the Literature.

BACKGROUND: Domperidone is a prokinetic agent used to treat pediatric gastroesophageal reflux disease. Health Canada has issued warnings about an increased risk of domperidone-associated ventricular arrhythmias and sudden cardiac death. However, the supporting data referred only to adult patients; therefore, extrapolating the safety risks to pediatric patients is difficult. OBJECTIVE: To summarize and evaluate the evidence for domperidone-associated QT interval prolongation, ventricular arrhythmias, and sudden cardiac death to determine the safety of this drug for pediatric patients. DATA SOURCES: Two databases (MEDLINE [1946 to August 2015] and Embase [1980 to August 2015]) were searched with the following Medical Subject Headings and keywords: "domperidone", "arrhythmias, cardiac", "death, sudden, cardiac", "electrocardiography", "heart diseases", "long QT syndrome", "tachycardia, ventricular", "torsades de pointes", and "ventricular fibrillation". The search was limited to studies conducted in humans under 18 years of age and published in English. STUDY SELECTION AND DATA EXTRACTION: Original research included in this review reported on the cardiac-related safety of domperidone in nononcologic patients under 18 years of age. DATA SYNTHESIS: Of the 5 studies meeting the inclusion criteria (n = 137 patients), one reported a statistically significant change in the corrected QT (QTc) interval, but the clinical significance was unclear. Most of the studies reported rare occurrences of pathological QTc intervals in a limited number of patients. However, confounding factors (e.g., abnormal electrolyte level or concurrent medications) were not consistently considered. Potential bias might have been alleviated by blinding of electrocardiogram (ECG) assessors; however, this was not consistently implemented. The designs of the included studies did not allow assessment of causality. The results should be interpreted with caution. CONCLUSIONS: Although the available evidence is limited, pathological QTc intervals were noted among a small number of infants, which supports the possibility of domperidone-associated risk of prolonged QTc interval. Because of the potential severity of QT interval prolongation, individual assessment and routine ECG monitoring should be implemented for patients receiving domperidone.

CONTEXTE: La dompéridone est un agent gastroprocinétique utilisé pour traiter le reflux gastro-œsophagien chez l'enfant. Santé Canada a publié des mises en garde à propos d'un risque accru d'arythmies ventriculaires et de mort subite cardiaque associées à la dompéridone. Or, comme les données probantes ne concernent que l'adulte, il est difficile de généraliser les risques pour la santé à l'enfant. OBJECTIF: Résumer et analyser les données probantes portant sur l'allongement de l'intervalle QT, les arythmies ventriculaires et la mort subite cardiaque associés à la dompéridone afin de déterminer le degré d'innocuité du médicament chez l'enfant. SOURCES DES DONNÉES: Deux bases de données (MEDLINE [1946 à août 2015] et EMBASE [1980 à août 2015]) ont été interrogées en utilisant les mots clés et les Medical Subject Headings (MeSH) suivants : « domperidone ¼ (dompéridone), « arrhythmias, cardiac ¼ (arythmies cardiaques), « death, sudden, cardiac ¼ (mort, subite, cardiaque), « electrocardiography ¼ (électrocardiographie), « heart diseases ¼ (cardiopathies), « long QT syndrome ¼ (syndrome du QT long), « tachycardia, ventricular ¼ (tachycardie, ventriculaire), « torsades de pointes ¼ (torsades de pointes) et « ventricular fibrillation ¼ (fibrillation ventriculaire). La recherche se limitait aux études publiées en anglais et effectuées chez l'humain de moins de 18 ans. SÉLECTION DES ÉTUDES ET EXTRACTION DES DONNÉES: Les études retenues dans la présente revue abordaient l'innocuité cardiaque de la dompéridone chez les patients de moins de 18 ans qui ne sont pas atteints d'un cancer. SYNTHÈSE DES DONNÉES: Parmi les cinq études qui répondaient aux critères d'inclusion (n = 137 patients), une indiquait un changement statistiquement significatif dans l'intervalle QT corrigé (QTc), mais la signification clinique demeurait floue. La plupart des études signalaient de rares cas d'intervalles QTc pathologiques chez un nombre limité de patients. Cependant, des facteurs de confusion (déséquilibre électrolytique ou emploi concomitant de médicaments, par exemple) n'étaient pas systématiquement pris en compte. Il aurait été possible d'éviter de potentiels biais en tenant les lecteurs d'électrocardiogramme (ECG) dans l'ignorance du traitement, mais cette mesure n'était pas toujours mise en œuvre. Les plans des études retenues ne permettaient pas d'évaluer la causalité. Il faut donc interpréter les résultats avec prudence. CONCLUSIONS: Bien qu'il n'y ait que peu de données probantes, des cas d'intervalles QTc pathologiques ont été relevés chez un petit nombre de nourrissons, ce qui vient appuyer le risque possible d'allongement de l'intervalle QTc associé à la dompéridone. À cause de la potentielle gravité de l'allongement de l'intervalle QT, une évaluation individuelle et une surveillance ECG systématique doit être mise en place pour les patients qui reçoivent de la dompéridone.

Chemokine-receptor interactions: GPCRs, glycosaminoglycans and viral chemokine binding proteins.

A key feature of the immune system is the migration of leukocytes throughout the organism in an effort to patrol for infectious pathogens, tissue damage, and other physiological insults. This remarkable surveillance system is controlled by a family of proteins called chemokines (chemoattractant cytokines), and their respective receptors. Originally discovered because of their role in cell recruitment during inflammation, it is now well recognized that chemokines are also involved in other diverse processes including lymphocyte development and homing, organogenesis, and neuronal communication. While chemokines have evolved largely for host protection, their ability to induce cell damage and inappropriate cell recruitment, can lead to disease. Thus, there is considerable interest in developing antagonists. In this review we emphasize what is known about the structural biology of chemokines, chemokine receptors, and interactions with cell surface glycosaminoglycans. We also briefly describe their role in certain diseases and strategies for interfering with chemokine function that have emerged from mechanistic and structural understanding of their function. Finally we discuss viral mechanisms for sabotaging or manipulating the chemokine system, in part to illustrate the level of molecular mimicry that viruses have achieved and the evolutionary pressure imposed on the immune system by these pathogens.

Stroke prophylaxis in institutionalized elderly patients with atrial fibrillation.

OBJECTIVES: To identify patterns and predictors of antithrombotic use and to evaluate the appropriateness of antithrombotic therapy for stroke prophylaxis in institutionalized elderly patients with atrial fibrillation. DESIGN: Retrospective study. SETTING: Seventeen long-term care institutions in Edmonton, Alberta. SUBJECTS: Two hundred sixty-five long-term care residents, aged 65 and older, with atrial fibrillation. MEASUREMENTS: The proportion of patients who were prescribed warfarin, acetylsalicylic acid (ASA), both, or neither was determined. Odds ratios were calculated to identify risk factors for stroke and bleeding that are predictive of the receipt of anticoagulant therapy. Appropriateness of therapy was evaluated based on whether patients were prescribed antithrombotic therapy in accordance with their risk factors for stroke and bleeding. RESULTS: Warfarin was prescribed for 49% of patients, ASA for 22%, both for 8%, and neither for 20%. Nearly all patients (97%) were considered to be at high risk for stroke, with age being the predominant risk factor (88%>75), whereas about half were considered to be at low risk for bleeding. Multivariate analyses did not find any associations between individual risk factors for bleeding and anticoagulant treatment, with the exception of recent surgery (odds ratio=0.59, 95% confidence interval=0.37-0.94). Overall, 54.8% of patients received appropriate antithrombotic therapy. Of patients who were optimal candidates for anticoagulation, 60% received appropriate therapy (warfarin with or without ASA). CONCLUSION: Although warfarin was the most appropriate treatment in nearly all of this population at high risk for stroke, it was prescribed in fewer than two-thirds of patients. Antithrombotic therapy was not always prescribed in accordance with patients' risk factors for stroke and bleeding. There is a need for systematic identification of appropriate candidates for anticoagulation in the long-term care setting.