Diagnosis of Leishmania infantum infection by Polymerase Chain Reaction in wild mammals

Visceral leishmaniasis is a chronic infectious disease caused by Leishmania infantum (synonym: Leishmania chagasi) and transmitted by the sandfly Lutzomyia longipalpis in Brazil. It is an endemic zoonosis in several regions of the country, including Belo Horizonte (State of Minas Gerais). In urban areas, the domestic dog is susceptible and considered the most important animal reservoir. However, L. infantum has been previously diagnosed in other species, including captive primates and canids. This study aimed to evaluate the presence of the agent DNA in captive animals as well as some free ranging animals from the Zoo-Botanical Foundation of Belo Horizonte by Polymerase Chain Reaction. Eighty one blood samples from primates, carnivores, ruminants, edentates, marsupial, and a monogastric herbivore were analyzed. Three primates Alouatta guariba (brown howler monkey), and two canids Speothos venaticus (bush dog) were positive, demonstrating the importance of leishmaniasis control in endemic areas for preservation of wildlife species in captivity.

Detection of Illicit Drugs and Drug Precursors with Cantilever-Enhanced Photoacoustic Spectroscopy

In this study, cantilever-enhanced photoacoustic spectroscopy (CEPAS) was applied in different drug detection schemes. The study was divided into two different applications: trace detection of vaporized drugs and drug precursors in the gas-phase, and detection of cocaine abuse in hair. The main focus, however, was the study of hair samples. In the gas-phase, methyl benzoate, a hydrolysis product of cocaine hydrochloride, and benzyl methyl ketone (BMK), a precursor of amphetamine and methamphetamine were investigated. In the solid-phase, hair samples from cocaine overdose patients were measured and compared to a drug-free reference group. As hair consists mostly of long fibrous proteins generally called keratin, proteins from fingernails and saliva were also studied for comparison. Different measurement setups were applied in this study. Gas measurements were carried out using quantum cascade lasers (QLC) as a source in the photoacoustic detection. Also, an external cavity (EC) design was used for a broader tuning range. Detection limits of 3.4 particles per billion (ppb) for methyl benzoate and 26 ppb for BMK in 0.9 s were achieved with the EC-QCL PAS setup. The achieved detection limits are sufficient for realistic drug detection applications. The measurements from drug overdose patients were carried out using Fourier transform infrared (FTIR) PAS. The drug-containing hair samples and drug-free samples were both measured with the FTIR-PAS setup, and the measured spectra were analyzed statistically with principal component analysis (PCA). The two groups were separated by their spectra with PCA and proper spectral pre-processing. To improve the method, ECQCL measurements of the hair samples, and studies using photoacoustic microsampling techniques, were performed. High quality, high-resolution spectra with a broad tuning range were recorded from a single hair fiber. This broad tuning range of an EC-QCL has not previously been used in the photoacoustic spectroscopy of solids. However, no drug detection studies were performed with the EC-QCL solid-phase setup.

The relationship between salivary cortisol concentrations and anxiety in adolescent and non-adolescent pregnant women

The main purpose of the present study was to determine the relationship between salivary cortisol concentrations and self-report anxiety in 50 adolescent and 178 non-adolescent women during the last month of pregnancy. The subjects were randomly selected from a previous study involving women who attended antenatal care from September 1997 to August 2000 at 17 health services in Southeast Brazil. Salivary cortisol was measured with an enzyme immunoassay kit, and anxiety was assessed by the State-Trait Anxiety Inventories (STAI) of Spielberger. After saliva collection, the participants completed the STAI. Mean concentrations of cortisol for both pregnant adolescents (14.17 ± 6.78 nmol/l) and non-adolescents (13.81 ± 8.51 nmol/l) were similar (P = 0.89). Forty-three percent of the pregnant adolescents and 30.5% of the non-adolescents felt anxious at the time of being questioned (State Anxiety Inventory (SAI) scores >40; P = 0.06). Cortisol concentrations in adolescents were negatively related to the SAI scores (r = -0.39; P = 0.01) which assess a temporary condition of anxiety. There was a statistically significant difference in mean cortisol concentrations between adolescents with low (<=40) and high (>40) SAI scores (P = 0.03, t-test), but no differences for non-adolescents. The negative relationship between salivary cortisol concentrations and anxiety scores in adolescents may be due to puberty-related hormone differences during this period of life. Pregnant adolescents may possess unique biological or psychological characteristics compared to adults and non-pregnant adolescents. Thus, we need to know more about the hypothalamic-pituitary-adrenocortical axis of pregnant adolescents.

Relationship between Daily Habits, Oral Microbiota and Caries with Special Reference to Xylitol

Caries is a plaque-associated multifactorial chronic disease. Oral hygiene habits, sugar, and oral micobiota interactions are important for caries to occur. Xylitol has been shown to reduce caries mainly due to its effects on mutans streptococci (MS). The purpose of this study was to evaluate the relationship of daily oral health habits and bacterial level on the caries occurrence and to study the effect of xylitol on the composition of oral microflora. A total of 192, 10-12 years old, male school children had been screened for salivary MS. Healthy subjects with high MS counts participated in two parallel double-blinded, randomised, controlled trials. In the first 5-week trial, subjects were assigned into xylitol (n=35) and sorbitol gum (n=38) groups. At baseline, children were examined using International Caries Detection and Assessment System (ICDAS) criteria and interviewed for oral health habits. In the second 4-week trial, subjects were assigned into xylitol (n=25) and saccharine mouthrinse (n=25) groups. In the end of both interventions, saliva samples were collected. The samples were analysed for changes in MS counts and changes in the composition of the oral microbiota assessed by the Human Oral Microbe Identification Microarray (HOMIM). Relationships between daily habits, bacterial levels and caries were evaluated. Daily use of sweets and soft drinks were the habits significantly associated with caries severity measured by ICDAS Caries Index (CI), while toothbrushing was the only habit associated with the low caries severity. Abiotrophia defectiva and Actinomyces meyeri/ A. odontolyticus were significantly higher in caries-affected children while Shuttleworthia satelles was significantly higher in caries-free children. Xylitol showed significant reduction in salivary levels of MS in both trials. No significant effects on other members of the microbiota were found when evaluated by HOMIM. In conclusion, other members of oral microbiota than MS may be associated with caries occurrence or absence. The use of xylitol had significant effect on MS with no effects on the other members of the salivary microbiota.

Do whole-body vibration exercise and resistance exercise modify concentrations of salivary cortisol and immunoglobulin A?

A single bout of resistance exercise (RE) induces hormonal and immune responses, playing an important role in a long-term adaptive process. Whole-body vibration (WBV) has also been shown to affect hormonal responses. Evidence suggests that combining WBV with RE may amplify hormonal and immune responses due to the increased neuromuscular load. Therefore, the aim of this study was to evaluate salivary cortisol (Scortisol) and salivary IgA (SIgA) concentrations following a RE session combined or not with WBV. Nine university students (22.9 ± 5.1 years, 175.8 ± 5.2 cm, and 69.2 ± 7.3 kg) performed five sets of squat exercise (70% one-repetition-maximum) combined (R+V30) or not (R) with WBV at 30 Hz. Saliva samples were obtained before and after exercise. Subjects also rated their effort according to the Borg CR-10 scale (RPE). Data were analyzed by a mixed model. RPE was higher after R+V30 (8.3 ± 0.7) compared to R (6.2 ± 0.7). However, Scortisol (pre: 10.6 ± 7.6 and 11.7 ± 7.6, post: 8.3 ± 6.3 and 10.2 ± 7.2 ng/mL for R and R+V30, respectively) and SIgA concentrations (pre: 98.3 ± 22.6 and 116.1 ± 51.2, post: 116.6 ± 64.7 and 143.6 ± 80.5 µg/mL for R and R+V30, respectively) were unaffected. No significant correlations were observed between Scortisol and RPE (r = 0.45, P = 0.22; r = 0.30, P = 0.42, for R and R+V30, respectively). On the basis of these data, neither protocol modified salivary cortisol or IgA, although RPE was higher after R+V30 than R.

Salivary testosterone and immunoglobulin A were increased by resistance training in adults with Down syndrome

This study was designed to assess the influence of resistance training on salivary immunoglobulin A (IgA) levels and hormone profile in sedentary adults with Down syndrome (DS). A total of 40 male adults with DS were recruited for the trial through different community support groups for people with intellectual disabilities. All participants had medical approval for participation in physical activity. Twenty-four adults were randomly assigned to perform resistance training in a circuit with six stations, 3 days per week for 12 weeks. Training intensity was based on functioning in the eight-repetition maximum (8RM) test for each exercise. The control group included 16 age-, gender-, and BMI-matched adults with DS. Salivary IgA, testosterone, and cortisol levels were measured by ELISA. Work task performance was assessed using the repetitive weighted-box-stacking test. Resistance training significantly increased salivary IgA concentration (P=0.0120; d=0.94) and testosterone levels (P=0.0088; d=1.57) in the exercising group. Furthermore, it also improved work task performance. No changes were seen in the controls who had not exercised. In conclusion, a short-term resistance training protocol improved mucosal immunity response as well as salivary testosterone levels in sedentary adults with DS.

Psoriasis severity and hypothalamic-pituitary-adrenal axis function: results from the CALIPSO study

Psoriasis is a chronic inflammatory disease that significantly impacts life quality, being associated with stress and mental disorders. We investigated whether the activity of the hypothalamic-pituitary-adrenal (HPA) axis was associated with psoriasis severity, daily life stress and anxiety, and depressive symptoms. In this ancillary study, which was part of the CALIPSO (coronary artery calcium in psoriasis) study, saliva was collected from 102 patients with psoriasis immediately upon awakening, 30, and 60 min after awakening, at 2:00 pm and at bedtime (five time points) to determine salivary cortisol levels. We used Pearson's correlation coefficient to evaluate the association of clinical and psychopathological variables with HPA activity. We found a direct correlation between bedtime cortisol and psoriasis severity evaluated by the psoriasis area severity index (PASI; r=0.39, P<0.001). No correlations between other clinical and psychopathological variables or with other cortisol assessments were observed. The findings indicated that HPA dysfunction may be present in psoriasis, as bedtime cortisol was correlated with psoriasis severity. Our study is limited by the lack of a control group; therefore, we were not able to explore whether these cortisol values were different compared with a concurrent, healthy sample.

Probiotics and oral health: In vitro and clinical studies

Aino Toiviainen Probiotics and oral health: in vitro and clinical studies University of Turku, Faculty of Medicine, Institute of Dentistry, Periodontology, Finnish Doctoral Program in Oral Sciences (FINDOS-Turku), Turku, Finland Annales Universitatis Turkuensis, Sarja – Ser. D, Medica-Odontologica. Painosalama Oy, Turku, Finland, 2015 Probiotics are used, for example, to prevent and treat diarrhea, allergies and respiratory infections, and there is an increasing interest to use probiotics also for oral health purposes. The most commonly used probiotic bacteria are lactobacilli and bifidobacteria, which are acidogenic and aciduric. From the oral point of view, use of these probiotics may, at least in theory, mean an increased risk of caries. In this thesis, the effects of probiotics on oral microbial composition, acid production of dental plaque and gingival health were studied through in vitro studies and two clinical studies. In a randomized, double-blind and crossover study, 13 healthy adults were allocated into two groups. Half of the subjects first consumed Lactobacillus rhamnosus GG tablets twice a day for two weeks, and after the washout period, L. reuteri tablets twice a day for two weeks. The other half of the subjects used the tablets in reverse order. In another controlled, randomized and double-blind study, 62 healthy adults were allocated into two groups. One group used the test tablets containing L. rhamnosus GG and B. lactis BB-12 and the other group used control tablets without probiotics. The recommendation for the use of the tablets was 4 per day for 4 weeks. Probiotic lactobacilli interfered with S. mutans biofilm formation and the adhesion of S. mutans to saliva-coated hydroxyapatite in vitro. No effect was found in S. mutans levels in the three-species biofilms. In clinical studies, the studied probiotics had no effect on the acid production of plaque. The counts of mutans streptococci and the oral microbial composition remained the same. Tablets containing L. rhamnosus GG and Bifidobacterium animalis subsp. lactis BB-12 did decrease the amount of plaque and gingival bleeding. According to our results, it seems that probiotics have beneficial effects on gingival health. The present results confirmed that probiotics are safe and have beneficial effects on oral health. Since the consumption of probiotics by the general population is steadily increasing, an understanding of the functions of probiotics in the oral cavity has become more important. Keywords: lactobacilli, bifidobacteria, caries, periodontal disease, mutans streptococci, probiotics

Secretory immunity in overweight and obese versus normal-weight early-and late-pubertal females

Obesity is a condition associated with a wide variety of health problems including hypertension, dyslipidemia, diabetes mellitus, certain forms of cancer, cardiovascular disease, and gallstones (157). TTiere is growing evidence that obesity may also be related to compromised immune function due to altered metabolic, psychological, and physical attributes (93). The aim of this study was to compare: a) immunity-related variables such as frequency of upper respiratory tract infections (URTI) and salivary secretory immunoglobulin A (sIgA) levels between overweight/obese (OB) and normal weight (NW) early-pubertal and late-pubertal girls, and b) stress-related variables such as Cortisol, melatonin, the melatonin/cortisol ratio, testosterone and the testosterone/cortisol ratio. Physical activity levels, stress indicators, and fatigue were used to explain potential differences in the dependent variables. It was hypothesized that the OB females would have lower melatonin (M) and higher Cortisol (C) and testosterone (T) levels compared with NW girls, regardless of maturity status. The altered levels of melatonin, Cortisol, and testosterone, would result in decreased M/C and T/C ratios, despite the increase in testosterone in OB females. It was hypothesized that this altered hormonal status results in a compromised immunity marked by higher frequency of upper respiratory tract infections (URTI) and decreased levels of secretory immunoglobulin A (sIgA). It was also hypothesized that OB girls would participate in less hours of physical activity than their NW counterparts and that this would relate to their stress and immunity levels. Forty (16 early- and 24 late-pubertal) overweight and obese females were compared to fifty-three (27 eariy- and 26 late-pubertal) age-matched normal-weight control subjects. Participants were categorized as early-pubertal (EP) or late-pubertal (LP) using Tanner self-staging of secondary sex characteristics. Subjects were classified into the two adiposity groups according to relative body fat (%BF), where normal weight (NW) subjects had a %BF less than 25%, and overweight and obese (OB) subjects had a %BF greater than 27.5%. Participants completed a number of questionnaires and information was collected on menstrual history, smoking history, alcohol and caffeine consumption, and medical history. Following the determination of maturity status, a complete anthropometric assessment was made including height, body mass, and body composition. All questionnaires and measurements were completed during a one-hour visit between 1 500 and 1900 hours Relative body fat was assessed using bioelectrical impedance analysis. Resting saliva samples were obtained and assayed (ELISA) for testosterone, Cortisol, melatonin and secretory immunoglobulin A. Physical activity was self-reported using the Godin- Shephard Leisure time questionnaire, and quantified using Actigraph GTIM accelerometers, which participants wore for seven consecutive days from the time they woke up in the morning, until the time they went to bed. Late-pubertal girls also completed questionnaires on their perceived stress and fatigue. Finally, all participants also filled out a one-month health log to record frequency of symptoms of upper respiratory tract infections (URTI). Significant age effects were found for testosterone, Cortisol, incidence of sickness, and sIgA when controlling for physical activity, however there were no significant effects of adiposity on any of the variables. There was a trend which neared-significance for an effect of adiposity on sIgA (p=0.01). There were no significant differences between the groups on the total selfreported leisure-time physical activity in METs per week, however EP girls recorded significantly greater levels of moderate, hard, and very hard physical activity from accelerometers. Results of the perceived stress and fatigue questionnaires in late-pubertal girls demonstrated that contrary to what was hypothesized, NW girls reported more stress and more fatigue than OB girls. Results of the present study suggest that excess adiposity in early- and latepubescent girls may not have a negative impact on immunity as hypothesized.

Social neuroendocrinology of competition

The relationship between testosterone concentrations and aggressive behaviour in studies of people has produced very inconsistent findings. However, one consistent fmding that has emerged is that competitive and aggressive interactions potentiate testosterone release in both human and non-human species. It has been argued that socially-induced alterations in testosterone concentrations may function to influence ongoing and/or future social behaviour. Nonetheless, few studies have empirically tested this hypothesis. The current series of experiments was designed to address the extent to which competitioninduced fluctuations in testosterone concentrations were associated with ongoing and/or subsequent social behaviour. In Study 1, men (n = 38) provided saliva samples prior to, and at the conclusion of, the Point Subtraction Aggression Paradigm (PSAP). Although baseline testosterone concentrations were not related to aggressive behaviour, there was a positive correlation between change in testosterone and aggressive behaviour such that men who were most aggressive on the PSAP demonstrated the largest increase in testosterone concentrations. Furthermore, a rise in testosterone during the PSAP predicted willingness to choose a subsequent competitive task. In Study 2, men and women provided saliva samples prior to and after competing against a same-sex opponent on the Number Tracing Task (NTT). The outcome of the competition was rigged such that half of the individuals won most of the races, while the other half lost most of the races, thus experimentally creating a winner and loser in the laboratory. Following the competitive interaction, men and women played the PSAP with their same-sex partner. Results indicated that men selected the aggressive response (but not reward or protection responses), more frequently than women. For men assigned to the loss condition, an increase in testosterone concentrations in response to the NTT predicted subsequent aggressive behaviour. For men assigned to the win condition, an increase in testosterone concentrations in response to the NTT predicted subsequent aggressive behaviour, but only among those men who scored high on trait dominance. Change in testosterone and trait dominance did not predict aggressive behaviour in women. In Study 3, men provided saliva samples prior to, during, and at the end of the PSAP. They were randomly assigned to one of four experimental conditions that differed in the extent to which they were provoked and whether they received reward for behaving aggressively (i.e., stealing points). Results indicated that baseline testosterone concentrations did not correlate with aggression in any of the experimental conditions. Consistent with Study 1, there was a positive correlation between change in testosterone and aggressive behaviour among men who were provoked, but did not receive reward for aggression (i.e., reactive condition). Men who were provoked but did not receive reward for aggression enjoyed the task the most and were more likely to choose the competitive versus non-competitive task relative to men assigned to the other experimental conditions. Also, individual differences in aggressive behaviour among these men were positively correlated with the extent to which they enjoyed the task. Together, these studies indicate that testosterone dynamics within the context of competition influence subsequent competitive and aggressive behaviours in humans and that testosterone may be a marker of the intrinsically rewarding nature of costly aggressive behaviour.

The Effects of a Social-Evaluative Body Image Threat on Shame, Social Physique Anxiety, Body Dissatisfaction and Cortisol Responses in University Men

Men struggle with body image concerns particularly related to the desire to be muscular. In women, social-evaluative body image threats have been linked to increased shame and cortisol responses, consistent with social self-preservation theory (SSPT), but no research has investigated these responses in men. Men (n = 66) were randomly assigned to either a social-evaluative threat (SET) or non-social-evaluative threat (N-SET) condition. Participants provided saliva samples and completed body shame, body dissatisfaction and social physique anxiety measures prior to and following their condition, during which anthropometric and strength measures were assessed. Results indicated men in the SET condition had higher body shame, social physique anxiety, and body dissatisfaction and had higher levels of cortisol than men in the N-SET condition post-social-evaluative threat. These findings, consistent with SSPT, suggest that social-evaluative body image threats may lead to increased body shame and social physique anxiety, greater body dissatisfaction and higher cortisol levels.

Acute endocrine responses to plyometrics versus resistance exercise in children

The purpose of this study was to examine the acute hormonal responses to a bout of resistance versus plyometric exercise in young male athletes. Specifically, changes in salivary cortisol, testosterone and testosterone-to-cortisol ratio from pre- to post-exercise between the two different exercise protocols were examined. Twenty-six peri-pubertal active boys participated in this cross-over study, completing two exercise sessions. During each session, participants first completed a 30 min control period, which did not include any exercise, and then was randomly assigned to perform a 45 min of either a resistance exercise or a plyometric exercise protocol. All participants crossed over to perform the other exercise protocol during their second exercise session, a week later. Four saliva samples during each protocol were taken at: baseline, pre-exercise, 5 min post-exercise and 30 min post-exercise. Significant increases in testosterone values were reported 5 min post-exercise following the resistance protocol, but not the plyometric protocol. Both exercise protocols resulted in significant cortisol decreases overtime, as well as significant testosterone-to-cortisol ratio increases. The post-exercise increases in salivary testosterone and testosterone-to-cortisol ratio followed the typical exercise induced anabolic response seen in adults. However, the post-exercise decrease in salivary cortisol was different than the typical adult response indicating an insufficient stimulus for this age group maybe due to their stage of the biological development. Thus, in the adolescent boys, exercise appears to change the anabolic to catabolic balance in favor of anabolism.

Influence d’un rince-bouche fluoré sur la corrosion galvanique entre un fil NiTi ou un fil CuNiTi et différents boîtiers orthodontiques : incidence sur les propriétés mécaniques des fils

Objectif : il a été rapporté que l’utilisation d’agents prophylactiques fluorés pouvait favoriser la corrosion galvanique au sein des alliages de titane. L’objectif de la présente étude était d’évaluer l’effet d’un rince-bouche fluoré sur les propriétés mécaniques de fils en nickel-titane (NiTi) et de fils en cuivre-nickel-titane (CuNiTi) lorsque ces derniers sont couplés à des boîtiers de compositions différentes (boîtiers de marques Smartclip, Clarity, et Sprint). Matériels et Méthodes : 90 segments de fils en NiTi et 90 segments de fils en CuNiTi ont été chacun couplés à 2 boîtiers de chaque marque. Chaque assemblage fil-boîtiers a été par la suite incubé pendant 3 heures à 37°C, soit dans une solution de fluore neutre (Fluorinse™ 0,05% NaF), soit dans une solution de salive artificielle (solution contrôle). Suite à l’incubation, les échantillons étaient nettoyés avec de l’eau déshydrogénée, les fils séparés des boîtiers et montés sur un support pour subir un test de pliage en trois points en milieu humide (salive artificielle) à 37°C. Les modules d’élasticité ainsi que les limites conventionnelles d’élasticité en activation et en désactivation ont été mesurés et comparés. Des analyses de Variance (ANOVA) et des comparaisons post-hoc avec la correction de Bonferronni ont été utilisées pour comparer les groupes entre eux (α = 0,05). Résultats : L’utilisation d’un rince-bouche fluoré a produit une réduction du module d’élasticité et de la limite conventionnelle d’élasticité en activation et en désactivation pour les fils en NiTi ; cependant, cet effet a été modulé par le type de boîtier auquel le fil a été couplé. Les propriétés mécaniques de fils en CuNiTi n’ont pas été affectées par le fluor, ou par le type de boîtier utilisé. Conclusions : L’utilisation d’un rince-bouche fluoré modifie les propriétés mécaniques des fils en NiTi seulement. Cet effet est modulé par le boîtier auquel le fil en NiTi est couplé. A la différence des autres études publiées dans la littérature, nos résultats ne nous permettent pas de conclure que la modification des propriétés mécaniques des fils en NiTi entrainerait obligatoirement un allongement de la durée du traitement orthodontique. Mots clés : Fluor, fils nickel-titane, boîtiers orthodontiques, corrosion galvanique, propriétés mécaniques.

Investigating the role of potential genetic markers that can predict risk for steroid refractory inflammatory bowel disease

Contexte - La variation interindividuelle de la réponse aux corticostéroïdes (CS) est un problème important chez les patients atteints de maladies inflammatoires d’intestin. Ce problème est bien plus accentué chez les enfants avec la prévalence de la corticodépendance extrêmement (~40 %) élevée. La maladie réfractaire au CS a des répercussions sur le développement et le bien-être physique et psychologique des patients et impose des coûts médicaux élevés, particulièrement avec la maladie active comparativement à la maladie en rémission, le coût étant 2-3 fois plus élevé en ambulatoire et 20 fois plus élevé en hôpital. Il est ainsi primordial de déterminer les marqueurs prédictifs de la réponse aux CS. Les efforts précédents de découvrir les marqueurs cliniques et démographiques ont été équivoques, ce qui souligne davantage le besoin de marqueurs moléculaires. L'action des CS se base sur des processus complexes déterminés génétiquement. Deux gènes, le ABCB1, appartenant à la famille des transporteurs transmembraneaux, et le NR3C1, encodant le récepteur glucocorticoïde, sont des éléments importants des voies métaboliques. Nous avons postulé que les variations dans ces gènes ont un rôle dans la variabilité observée de la réponse aux CS et pourraient servir en tant que les marqueurs prédictifs. Objectifs - Nous avons visé à: (1) examiner le fardeau de la maladie réfractaire aux CS chez les enfants avec la maladie de Crohn (MC) et le rôle des caractéristiques cliniques et démographiques potentiellement liés à la réponse; (2) étudier l'association entre les variantes d'ADN de gène ABCB1 et la réponse aux CS; (3) étudier les associations entre les variantes d'ADN de gène NR3C1 et la réponse aux CS. Méthodes - Afin d’atteindre ces objectifs, nous avons mené une étude de cohorte des patients recrutés dans deux cliniques pédiatriques tertiaires de gastroentérologie à l’Ottawa (CHEO) et à Montréal (HSJ). Les patients avec la MC ont été diagnostiqués avant l'âge de 18 ans selon les critères standard radiologiques, endoscopiques et histopathologiques. La corticorésistance et la corticodépendance ont été définies en adaptant les critères reconnus. L’ADN, acquise soit du sang ou de la salive, était génotypée pour des variations à travers de gènes ABCB1 et NR3C1 sélectionnées à l’aide de la méthodologie de tag-SNP. La fréquence de la corticorésistance et la corticodépendance a été estimée assumant une distribution binomiale. Les associations entre les variables cliniques/démographiques et la réponse aux CS ont été examinées en utilisant la régression logistique en ajustant pour des variables potentielles de confusion. Les associations entre variantes génétiques de ABCB1 et NR3C1 et la réponse aux CS ont été examinées en utilisant la régression logistique assumant différents modèles de la transmission. Les associations multimarqueurs ont été examinées en utilisant l'analyse de haplotypes. Les variantes nongénotypées ont été imputées en utilisant les données de HAPMAP et les associations avec SNPs imputés ont été examinées en utilisant des méthodes standard. Résultats - Parmi 645 patients avec la MC, 364 (56.2%) ont reçu CS. La majorité de patients étaient des hommes (54.9 %); présentaient la maladie de l’iléocôlon (51.7%) ou la maladie inflammatoire (84.6%) au diagnostic et étaient les Caucasiens (95.6 %). Huit pourcents de patients étaient corticorésistants et 40.9% - corticodépendants. Le plus bas âge au diagnostic (OR=1.34, 95% CI: 1.03-3.01, p=0.040), la maladie cœxistante de la région digestive supérieure (OR=1.35, 95% CI: 95% CI: 1.06-3.07, p=0.031) et l’usage simultané des immunomodulateurs (OR=0.35, 95% CI: 0.16-0.75, p=0.007) ont été associés avec la corticodépendance. Un total de 27 marqueurs génotypés à travers de ABCB1 (n=14) et NR3C1 (n=13) ont été en l'Équilibre de Hardy-Weinberg, à l’exception d’un dans le gène NR3C1 (rs258751, exclu). Dans ABCB1, l'allèle rare de rs2032583 (OR=0.56, 95% CI: 0.34-0.95, p=0.029) et génotype hétérozygote (OR=0.52, 95% CI: 0.28-0.95 p=0.035) ont été négativement associes avec la dépendance de CS. Un haplotype à 3 marqueurs, comprenant le SNP fonctionnel rs1045642 a été associé avec la dépendance de CS (p empirique=0.004). 24 SNPs imputés introniques et six haplotypes ont été significativement associés avec la dépendance de CS. Aucune de ces associations n'a cependant maintenu la signification après des corrections pour des comparaisons multiples. Dans NR3C1, trois SNPs: rs10482682 (OR=1.43, 95% CI: 0.99-2.08, p=0.047), rs6196 (OR=0.55, 95% CI: 0.31-0.95, p=0.024), et rs2963155 (OR=0.64, 95% CI: 0.42-0.98, p=0.039), ont été associés sous un modèle additif, tandis que rs4912911 (OR=0.37, 95% CI: 0.13-1.00, p=0.03) et rs2963156 (OR=0.32, 95% CI: 0.07-1.12, p=0.047) - sous un modèle récessif. Deux haplotypes incluant ces 5 SNPs (AAACA et GGGCG) ont été significativement (p=0.006 et 0.01 empiriques) associés avec la corticodépendance. 19 SNPs imputés ont été associés avec la dépendance de CS. Deux haplotypes multimarqueurs (p=0.001), incluant les SNPs génotypés et imputés, ont été associés avec la dépendance de CS. Conclusion - Nos études suggèrent que le fardeau de la corticodépendance est élevé parmi les enfants avec le CD. Les enfants plus jeunes au diagnostic et ceux avec la maladie coexistante de la région supérieure ainsi que ceux avec des variations dans les gènes ABCB1 et NR3C1 étaient plus susceptibles de devenir corticodépendants.

Stabilité de l’acide ribonucléique pour la datation des fluides corporels en biologie judiciaire

Projet de recherche réalisé en collaboration avec la section Biologie/ADN du Laboratoire de sciences judiciaires et de médecine légale (LSJML) de Montréal.