Impact of probe compound in MRP2 vesicular transport assays

MRP2 is an efflux transporter that is expressed mainly in the canalicular membrane of hepatocytes, where it expels polar and ionic compounds into the bile. MRP2 is also present in the apical membrane of enterocytes and epithelial cells of proximal tubules of the kidney. Inhibition of MRP2 transport can lead to the accumulation of metabolites and other MRP2 substrates up to toxic levels in these cells. The transport properties of MRP2 are frequently studied with the vesicular transport assay. The assay identifies compounds that interact with MRP2 by measuring the effect of a compound on the transport of a radioactively labeled or fluorescent probe. We have compared the effect of eight selected test compounds (quercetin, disopyramide, paracetamol, indomethacin, diclofenac, estrone-3-sulfate, budesonide, and thioridazine) on the MRP2-mediated transport of three commonly used probes: 5(6)-carboxy-2,7-dichlorofluorescein, leukotriene C4 and estradiol-17-β-d-glucuronide (E217βG). Five of the test compounds had different probe-dependent effects on the MRP2-mediated transport, suggesting differences in the transport mechanism of the probes. Our results underline the complexity of substrate recognition by these efflux transporters and the difficulties in directly comparing results obtained with different assays, especially when different probes are used.     

The effectiveness of community-based delivery of an evidence-based treatment for adolescent substance use

This study evaluates the effectiveness of motivational enhancement therapy/cognitive behavioral therapy-5 (MET/CBT-5) when delivered in community practice settings relative to standard community-based adolescent treatment. A quasi-experimental strategy was used to adjust for pretreatment differences between the MET/CBT-5 sample (n = 2,293) and those who received standard care (n = 458). Results suggest that youth who received MET/CBT-5 fared better than comparable youth in the control group on five of six 12-month outcomes. A low follow-up rate (54%) in the MET/CBT-5 sample raised concerns about nonresponse bias in the treatment effect estimates. Sensitivity analyses suggest that although modest differences in outcomes between the MET/CBT-5 nonrespondents and respondents would yield no significant differences between the two groups on two of the six outcomes, very large differences in outcomes between responders and nonresponders would be required for youth receiving MET/CBT-5 to have fared better had they received standard outpatient care.     

Inhibition of human recombinant T-type calcium channels by N-arachidonoyl 5-HT

BACKGROUND AND PURPOSE

N-arachidonoyl 5-HT (NA-5HT) has anti-nociceptive effects reported to be mediated by inhibitory actions at the transient receptor potential vanilloid receptor 1 (TRPV1) and fatty acid amide hydrolase (FAAH). Anandamide and N-arachidonoyl dopamine (NA-DA), endocannabinoids that activate TRPV1 or are metabolized by FAAH, also inhibit T-type calcium channels (I_Ca). T-type I_Ca are expressed by many excitable cells, including neurons involved in pain detection and processing. We sought to determine whether NA-5HT also modulates T-type I_Ca.

EXPERIMENTAL APPROACH

Human recombinant T-type I_Ca (Ca_V3 channels) expressed in HEK 293 cells were examined using standard whole-cell voltage-clamp electrophysiology techniques.

KEY RESULTS

NA-5HT completely inhibited Ca_V3 channels with a rank order of potency (pEC₅₀) of Ca_V3.1 (7.4) > Ca_V3.3 (6.8) ≥ Ca_V3.2 (6.6). The effects of NA-5HT were voltage-dependent, and it produced significant hyperpolarizing shifts in Ca_V3 steady-state inactivation relationships. NA-5HT selectively affected Ca_V3.3 channel kinetics.

CONCLUSIONS AND IMPLICATIONS

NA-5HT increases the steady-state inactivation of Ca_V3 channels, reducing the number of channels available to open during depolarization. These effects occur at NA-5HT concentrations at or below those at which NA-5HT affects TRPV1 receptors and FAAH. NA-5HT is one of the most potent inhibitors of T-type I_Ca described to date, and it is likely to exert some of its biological effects, including anti-nociception, via inhibition of these channels.     

Celiac disease in patients with type 1 diabetes: a condition with distinct changes in intestinal immunity?

Two common chronic childhood diseases-celiac disease (CD) and type 1 diabetes (T1D)-result from complex pathological mechanisms where genetic susceptibility, environmental exposure, alterations in intestinal permeability and immune responses play central roles. In this study, we investigated whether these characteristics were universal for CD independently of T1D association. For this purpose, we studied 36 children with normal small-bowel mucosa and 26 children with active CD, including 12 patients with T1D. In samples from the small-bowel mucosa, we detected the lowest expression of tight junction protein 1 (TJP1) mRNA in CD patients with T1D, indicating an increase in intestinal permeability. Furthermore, these samples displayed the highest expression of forkhead box P3 (FoxP3) mRNA, a marker for regulatory T cells, as compared with other patient groups. At the same time, serum levels of IgA antibodies specific for the CD-related antigens deamidated gliadin and tissue transglutaminase (tTG) were the highest in CD patients with T1D. In contrast, no significant differences were found in IgA or IgG antibodies specific for bovine beta-lactoglobulin or Bifidobacterium adolescentis DSM 20083-derived proteins. There were also no differences in the transamidating activity of serum autoantibodies between patients and control individuals. Our results show that patients with T1D and newly detected CD exhibit severely altered intestinal permeability, strong local immune activation and increased immunoregulatory mechanisms in the small bowel. Further study is required to determine whether these extreme changes in this CD subgroup are due to some specific environmental factors (virus infections), unknown genetic effects or autoimmune reactions to antigenic targets in intracellular tight junctions.     

Modulation of circulating purines and pyrimidines by physical exercise in the horse

This study was designed to examine the influence of sub-maximal exercise on purine and pyrimidine catabolism in horses. Ten horses were initially trained for 12 weeks at the end of which they underwent a standardized exercise test (SET); venous blood samples were taken at rest, 5 and 30 min after the SET. Six untrained healthy horses, from which a blood withdrawal was taken at rest, were used as the control group. Samples were analyzed by HPLC for the simultaneous determination of uric acid, uridine, β-pseudouridine and creatinine in plasma. Glucose and lactate were measured in blood. Trained horses had basal uridine levels significantly lower than sedentary horses. The SET caused significant increase in plasma uric acid, uridine, β-pseudouridine and creatinine. Following the SET, a significant negative correlation was found between plasma uridine and glucose, whilst a significant positive correlation was observed between plasma uric acid and creatinine. These results indicate that increase in energy demand during exercise in the horse causes not only the degradation of purine but also of pyrimidine compounds, the latter possibly exerting a control on glucose uptake as also demonstrated in human beings.     

Soins primaires aux adultes ayant une d��ficience d��veloppementale: Lignes directrices consensuelles canadiennes

Objective

To update the 2006 Canadian guidelines for primary care of adults with developmental disabilities (DD) and to make practical recommendations based on current knowledge to address the particular health issues of adults with DD.

Quality of evidence

Knowledgeable health care providers participating in a colloquium and a subsequent working group discussed and agreed on revisions to the 2006 guidelines based on a comprehensive review of publications, feedback gained from users of the guidelines, and personal clinical experiences. Most of the available evidence in this area of care is from expert opinion or published consensus statements (level III).

Main message

Adults with DD have complex health issues, many of them differing from those of the general population. Good primary care identifies the particular health issues faced by adults with DD to improve their quality of life, to improve their access to health care, and to prevent suffering, morbidity, and premature death. These guidelines synthesize general, physical, behavioural, and mental health issues of adults with DD that primary care providers should be aware of, and they present recommendations for screening and management based on current knowledge that practitioners can apply. Because of interacting biologic, psychoaffective, and social factors that contribute to the health and well-being of adults with DD, these guidelines emphasize involving caregivers, adapting procedures when appropriate, and seeking input from a range of health professionals when available. Ethical care is also emphasized. The guidelines are formulated within an ethical framework that pays attention to issues such as informed consent and the assessment of health benefits in relation to risks of harm.

Conclusion

Implementation of the guidelines proposed here would improve the health of adults with DD and would minimize disparities in health and health care between adults with DD and those in the general population.Les expressions déficiences développementales (DD) ou déficiences intellectuelles sont utilisées indifféremment au Canada (équivalent de déficiences d’apprentissage au Royaume-Uni) pour désigner une gamme de problèmes se présentant comme des limites permanentes dans le fonctionnement intellectuel et les aptitudes conceptuelles, sociales et pratiques observées avant l’âge de 18 ans¹. On estime que la prévalence de la DD au Canada varie entre 1 % et 3 % de la population. La plupart de ces personnes résident et reçoivent des soins de santé dans la communauté². Une proportion grandissante d’entre elles vivent plus longtemps que par le passé^2,3. Leurs besoins en matière de santé et leur accès aux soins primaires varient d’une personne à l’autre, en fonction de facteurs comme l’étiologie de leur DD, la coexistence de caractéristiques sur le plan de la santé mentale et physique, la gravité des limites fonctionnelles, la qualité de l’environnement et des soutiens sociaux et l’âge⁴.Les problèmes de santé chez les personnes ayant une DD diffèrent souvent de ceux observés dans la population en général au chapitre de la prévalence, de l’âge de l’apparition, du taux de progression, du degré de gravité et de leurs manifestations. Ces troubles ont tendance à être multiples et plus complexes chez les personnes ayant une DD³. Ils exigent donc l’aide de professionnels de la santé qui sont disposés à les assister, bien renseignés et aptes à relever les défis et les vulnérabilités qui leur sont particuliers dans le maintien de la santé.Diverses études au Canada, aux États-Unis, au Royaume-Uni et en Australie ont démontré que, collectivement, les personnes ayant une DD ne sont pas bien prises en charge par les systèmes de santé⁵. La Convention relative aux droits des personnes handicapées⁶ de l’Organisation des Nations Unies, qu’a ratifiée le Canada, inclut les droits aux soins de santé. Les professionnels des soins primaires représentent le pivot des efforts pour améliorer les soins de santé aux personnes ayant une DD. Ils sont souvent les professionnels de la santé impliqués dans les soins aux personnes ayant une DD qui sont les plus uniformément accessibles et qui interagissent avec les proches aidants habituels. Leur contribution est essentielle pour la prévention des maladies, leur détection précoce et leur prise en charge appropriée. Ils peuvent aider à évaluer la nécessité d’une demande de consultation auprès de services de santé spécialisés et interdisciplinaires lorsqu’ils sont disponibles. Ils assurent également la continuité et la coordination des soins. Des lignes directrices fiables sont toutefois nécessaires pour renseigner les professionnels des soins primaires au sujet des besoins particuliers en matière de santé des personnes ayant une DD et des meilleures approches dans leur prise en charge.Il y a précisément un besoin urgent de disposer de telles directives concernant les adultes ayant une DD. À l’âge adulte, habituellement après 18 ans, les personnes ayant une DD ne sont plus admissibles aux soins pédiatriques ou pour adolescents, quoique l’âge limite varie d’une province à l’autre au Canada. Dans le système de soins canadien, les lacunes dans les services résultant de la transition au système pour les adultes, qui a généralement moins de ressources, est moins spécialisé et plus fragmenté que les systèmes pour enfants et adolescents, présentent des défis énormes aux adultes ayant une DD et à leur aidants. Ces problèmes se compliquent davantage compte tenu de l’espérance de vie plus longue, du vieillissement et de l’intégration dans la communauté des personnes ayant une DD. Par conséquent, si d’une part, les personnes ayant une DD qui passent au système de soins pour les adultes sont plus nombreuses que par le passé, d’autre part, les professionnels des soins primaires renseignés et expérimentés sont en nombre insuffisant pour les soutenir. Pour aggraver la situation, il y a eu bien moins de publications sur le dépistage, l’évaluation et la prise en charge des problèmes de santé et des défis des adultes ayant une DD par rapport à celui des publications portant sur de tels problèmes chez le nourrisson et l’enfant.En 2005, un colloque consensuel, mettant à contribution des cliniciens et des chercheurs renseignés et expérimentés en matière de DD, en provenance de tous les coins du Canada et de l’étranger, a produit des lignes directrices intitulées Consensus Guidelines for Primary Health Care of Adults with Developmental Disabilities (désignées ci-après sous le nom de lignes directrices de 2006)⁷. À la suite de consultations subséquentes auprès des utilisateurs des lignes directrices de 2006 et en raison des progrès dans la recherche et la pratique, on a jugé bon d’élargir et de mettre à jour ces lignes directrices qui sont, à notre connaissance, les seules directives complètes sur les soins primaires aux adultes ayant une DD au Canada. On a aussi ajouté divers outils cliniques susceptibles d’aider dans la mise en œuvre de ces lignes directrices.     

Subjective Sleep Quality During Average Volume Assured Pressure Support (AVAPS) Ventilation in Patients with Hypercapnic COPD: A Physiological Pilot Study

The aim of this short-term, single-blind, randomized, crossover study was to evaluate night-time efficacy of and compliance and physiological responses to Average Volume Assured Pressure Support (AVAPS) versus Pressure Support (PS) ventilation. AVAPS or PS ventilation was delivered to nine stable hypercapnic COPD patients via a mask over two 5-day periods during consecutive weeks. The Synchrony^® ventilator was used to deliver mask ventilation as follows: 8 ml/kg of ideal body weight (as the targeted inspiratory tidal volume) with IPAP ranging from EPAP up to 30 cmH₂O for AVAPS, and the patient’s highest tolerated IPAP level for PS. EPAP was set at the minimum level for both modalities and oxygen was added at a fixed inspiratory fraction to maintain SaO₂ above 90%. Arterial blood gases, comfort (by VAS), and perceived sleep efficiency (SE by questionnaire) were measured at baseline (T0) and after three (T1) and five (T2) nights over the two periods. Compliance to ventilation, as measured by mean usage (hours/night), was also recorded. Measurements were similar between the two treatment periods at baseline. PaCO₂ and comfort VAS similarly improved for both modalities, whereas the SE score significantly improved at T2 with AVAPS (from 5.1 ± 2.0 to 4.1 ± 2.2, P = 0.001) but not with PS (from 5.1 ± 1.7 to 4.7 ± 1.3, P = 0.219). No difference in mean usage was found between the two modalities. Mask AVAPS is as comfortable and effective as PS at reducing respiratory acidosis but produces better perceived sleep efficiency in stable hypercapnic COPD patients.     

Prognostic value of EEG performed at term age in preterm infants

Rationale Electroencephalography (EEG) was performed at term age on 32 infants born prematurely (25–32 weeks). EEG was assessed looking for overall background activity and transients.Methods A quantitative analysis was performed, selecting 5-min epochs of tracé alternant free of artefacts during quiet sleep. EEG findings were compared with cranial ultrasound (US) findings at term age and with neurodevelopmental outcome at 2 years (Students t-test).Results The overall EEG background activity was not always related to the outcome or to the severity of cranial US. Infants with normal US and normal outcome had longer synchrony percentage of bursts, longer maximum duration of bursts and shorter mean of abnormal transients per interbursts than children with major lesions and abnormal outcome. Infants with minor lesions, who all had normal outcome, also had better results than those with major lesions and abnormal outcome, but the range of the EEG findings was more variable.Conclusion Our results suggest that the EEG performed at term age does not provide additional prognostic information compared to cranial US.     

Ectopic parathyroid adenoma with Tc-99m MIBI washout: role of SPECT

The authors present a case of a 71-year-old woman with clinical and biochemical features of primary hyperparathyroidism and a history of right pneumonectomy. An ultrasound scan did not demonstrate any abnormality. A planar Tc-99m methoxyisobutylisonitrile (Tc-99m MIBI) scan showed an area of minimally increased uptake within the right hemithorax. However, unlike most adenomas, this demonstrated washout similar to the thyroid at 90 minutes and 3 hours. Subsequent SPECT imaging clearly showed the lesion in the superior right hemithorax. A CT scan and angiogram confirmed the presence of this mass. After surgery, histology confirmed the diagnosis of a parathyroid adenoma. Postoperatively, the calcium and PTH levels returned to normal.