Striatal and extrastriatal dopamine D2/3 receptors studied with [11C]raclopride and high-resolution PET

The human striatum is a heterogeneous structure representing a major part of the dopamine (DA) system’s basal ganglia input and output. Positron emission tomography (PET) is a powerful tool for imaging DA neurotransmission. However, PET measurements suffer from bias caused by the low spatial resolution, especially when imaging small, D2/3 -rich structures such as the ventral striatum (VST). The brain dedicated high-resolution PET scanner, ECAT HRRT (Siemens Medical Solutions, Knoxville, TN, USA) has superior resolution capabilities than its predecessors. In the quantification of striatal D2/3 binding, the in vivo highly selective D2/3 antagonist [11C] raclopride is recognized as a well-validated tracer. The aim of this thesis was to use a traditional test-retest setting to evaluate the feasibility of utilizing the HRRT scanner for exploring not only small brain regions such as the VST but also low density D2/3 areas such as cortex. It was demonstrated that the measurement of striatal D2/3 binding was very reliable, even when studying small brain structures or prolonging the scanning interval. Furthermore, the cortical test-retest parameters displayed good to moderate reproducibility. For the first time in vivo, it was revealed that there are significant divergent rostrocaudal gradients of [11C]raclopride binding in striatal subregions. These results indicate that high-resolution [11C]raclopride PET is very reliable and its improved sensitivity means that it should be possible to detect the often very subtle changes occurring in DA transmission. Another major advantage is the possibility to measure simultaneously striatal and cortical areas. The divergent gradients of D2/3 binding may have functional significance and the average distribution binding could serve as the basis for a future database. Key words: dopamine, PET, HRRT, [11C]raclopride, striatum, VST, gradients, test-retest.

Quality of 'Delta Valencia' orange grown in semiarid climate and stored under refrigeration after coating with wax

The effects of carnauba-based wax on the quality of 'Delta Valencia' orange produced in Ceará state, Brazil, were studied. The fruits were coated with carnauba-based wax and refrigerated (7 ± 2 ºC and 85 ± 2% R.H.) for 28 days. The quality attribute parameters assessed were weight loss, peel color (brightness, hue angle, and chromaticity), peel moisture, pH, soluble solids (SS), titratable acidity (TA), SS/TA ratio, ascorbic acid, total soluble sugars, reducing sugars, yellow flavonoids, and polyphenols. The results showed that 'Delta Valencia' oranges grown in the dry climate of Ceará state has excellent quality. The coated fruits lost mass at a lower rate than the the control fruits. No significant loss of soluble solids, titratable acidity, pH, and SS/TA ratio was observed, while ascorbic acid, soluble sugars, reducing sugars, yellow flavonoids, and polyphenols increased during storage in both the coated and control fruits. Carnauba-based wax coated fruits showed no signal of dehydration keeping their shiny green peel up to the end of the storage. The use of coating was crucial for the maintenance of visual quality by reducing mass loss, as well as keeping peel moisture.

Cat Scratch Disease in kidney transplant receptors: is it a rare or underdiagnosed pathology?

Cat Scratch Disease (CSD) is an infectious disorder which appears after cat scratching particularly in children and adolescents. Bartonella henselae is the etiologic agent more frequently involved. There are only a few recent reports demonstrating the disease after transplantation, although the illness is not infrequent in immunologically competent people. Indeed CSD in transplant receptors has only been recently emphasized in the literature and it was concluded that fever and lymphadenopathy in patients who had been exposed to cats should prompt clinicians to maintain a suspicion for the infection. In this report CSD infecting a renal transplanted adolescent complaining of headache, blurred vision and fever, presenting a cat scratching lesion in the right arm, with a bilateral painful cervical lymphadenopathy was related. He also presented indirect immunofluorescency identifying that the two subtype's titles of Bartonella-henselae and quintana- were elevated. Treatment with doxicicline e rifampicin was introduced and the patient became asymptomatic in about 3 weeks.

Pulsed laser deposition of YBa2Cu3O7-[delta]/PrBa2Cu3O7-[delta] /

The process of depositing thin films by the use of pulsed laser deposition (PLD) has become a more widely used technique for the growth of substances in a thin film form. Pulsed laser deposition allows for the stoichiometric film growth of the target which is of great significance in the deposition of High Temperature Superconducting materials. We will describe a system designed using an excimer laser and vaccum chamber in which thin films and superlattices of YBa2Cuj07_i, PrBa2Cu307_i, and YBajCujOr-j/ PrBajCusOr-^ were deposited on SrTiOs. Results of resistivity measurements using the four probe technique will be shown.

Expression and function of endothelin and its receptors in vascular adventitial fibroblasts

Objective: The adventitia has been recognized to play important roles in vascular oxidative stress, remodelling and contraction. We recently demonstrated that adventitial fibroblasts are able to express endothelin-1 (ET-1) in response to angiotensin II (ANG II). However, the mechanisms by which ANG II induces ET-1 expression are unknown. It is also unclear whether the ET-1 receptors are expressed in the adventitia. We therefore examined the role of oxidative stress in the regulation of ET-1. We also investigated the expression of both the ETA and ETB receptors and the roles of these two types of receptors in collagen synthesis and ET-1 clearance in adventitial fibroblasts. Methods and Results: Adventitial fibroblasts were isolated and cultured from the thoracic mouse aorta. Cells were treated with ANG II (lOOnM), ET-1 (lOpM), NADPH oxidase inhibitor apocynin (lOOfiM), the superoxide anion scavenger tempol (lOOfiM), the ANG II receptor antagonists (100[aM), losartan (AT| receptor) and PD 1233 19 (AT2 receptor), the ET-1 receptor antagonists (lOOuM), BQ123 (ETA receptor) and BQ788 (ETB receptor), and the ETB receptor agonist (lOOnM) Sarafotoxin 6C. ET-1 peptide levels were determined by ELISA, while ETA ,ETB and collagen levels were determined by Western blot. ANG II increased ET-1 peptide levels in a time-dependent manner reaching significance when incubated for 24 hours. NAD(P)H oxidase inhibitor, apocynin, as well as the superoxide scanverger, tempol, significantly reduced ANG Il-induced ET-1 peptide levels while over-expression of SOD1 (endogenous antioxidant enzyme) significantly decreased ANG Il-induced collagen I expression, therefore implicating reactive oxygen species in the mediation of ET-1. ANG II increased ETA receptor protein as well as collagen in a similar fashion, reaching significance after 4, 6, and 24 hours treatment. ANG II induced collagen was reduced while in the presence of the ETA receptor antagonist suggesting the role of the ETa receptor in the regulation of the extracellular matrix. ANG II treatment also increased ETB receptor protein levels in a time-dependent manner. ANG II treatment in the presence of the ETB receptor antagonist significantly increased ET-1 peptide levels. On another hand, the ETB receptor agonist, Sarafotoxin 6C, significantly decreased ET-1 peptide levels. These data implicate the role of the ETb receptor in the clearance of the ET-1 peptide. Conclusion: ANG II-induced increases of ET-1 peptide appears to be mediated by reactive oxygen species derived from NAD(P)H oxidase. Both the ETA and ETB receptors are expressed in adventitial fibroblasts. The ETA receptor subtype mediates collagen I expression, while the ETB receptor may play a protective role through increasing the clearance of the ET- 1 peptide.

Opioid poisoning and availability of specialized medical care in Ontario, 2002-2006

The prescription of opioid analgesics has risen sharply in North America over the past two decades. This increase has been accompanied by a rise in overdoses. The present study draws on administrative data collected from emergency department contacts to describe the epidemiology of opioid overdose in Ontario b~tween 2002 and 2006 and to examine the role of regional variation in availability of specialist care. The number of poisonings increased from 1250 (10.9 per 100,000) in FY2002 to 1816 (15.2 per 100,000) in FY2005. Local concentration of specialist physicians was significantly associated with the incidence of opioid overdose, inversely at most levels of availability, but positively at very high levels. Regional variation in incidence was also associated with demographics, median family income, and the rate of other drug poisonings. Policy options for limiting opioid-related harms are limited, but improvements in monitoring and clinical management may prove valuable.

Identification of novel retinoid receptors and their roles in vertebrate and invertebrate nervous systems

In vertebrates, signaling by retinoic acid (RA) is known to play an important role in embryonic development, as well as organ homeostasis in the adult. In organisms such as adult axolotls and newts, RA is also important for regeneration of the CNS, limb, tail, and many other organ systems. RA mediates many of its effects in development and regeneration through nuclear receptors, known as retinoic acid receptors (RARs) and retinoid X receptors (RXRs). This study provides evidence for an important role of the RA receptor, RAR~2, in ,( '. regeneration ofthe spinal cord and tail of the adult newt. It has previously been proposed that the ability of the nervous system to regenerate might depend on the presence or absence of this RAR~2 isoform. Here, I show for the very first time, that the regenerating spinal cord of the adult newt expresses this ~2 receptor isoform, and inhibition of retinoid signaling through this specific receptor with a selective antagonist inhibits tail and spinal cord regeneration. This provides the first evidence for a role of this receptor in this process. Another species capable of CNS ~~generation in the adult is the invertebrate, " Lymnaea stagnalis. Although RA has been detected in a small number of invertebrates (including Lymnaea), the existence and functional roles of the retinoid receptors in most invertebrate non-chordates, have not been previously studied. It has been widely believed, however, that invertebrate non-chordates only possess the RXR class of retinoid receptors, but not the RARs. In this study, a full-length RXR cDNA has been cloned, which was the first retinoid receptor to be discovered in Lymnaea. I then went on to clone the very first full-length RAR eDNA from any non-chordate, invertebrate species. The functional role of these receptors was examined, and it was shown that normal molluscan development was altered, to varying degrees, by the presence of various RXR and RAR agonists or antagonists. The resulting disruptions in embryogenesis ranged from eye and shell defects, to complete lysis of the early embryo. These studies strongly suggest an important role for both the RXR and RAR in non-chordate development. The molluscan RXR and RAR were also shown to be expressed in the adult, nonregenerating eNS, as well as in individual motor neurons regenerating in culture. More specifically, their expression displayed a non-nuclear distfibution, suggesting a possible non-genomic role for these 'nuclear' receptors. It was shown that immunoreactivity for the RXR was present in almost all regenerating growth cones, and (together with N. Farrar) it was shown that this RXR played a novel, non-genomic role in mediating growth cone turning toward retinoic acid. Immunoreactivity for the novel invertebrate RAR was also found in the regenerating growth cones, but future work will be required to determine its functional role in nerve cell regeneration. Taken together, these data provide evidence for the importance of these novel '. retinoid receptors in development and regeneration, particularly in the adult nervous system, and the conservation of their effects in mediating RA signaling from invertebrates to vertebrates.

Uso del programa Delta para el estudio de los hongos Aphyllophoralesno poroides de México

Tesis (Maestría en Ciencias Forestales) UANL

Evaluación de nuevos opioides agonistas no peptidicos del tipo delta y mu sobre las funciones inmunológicas de macrofagos y linfocitos de humano y rata, y sus efectos antitumorales en contra de líneas mieloides y linfoides

Tesis (Maestría en Ciencias con Especialidad en Inmunología) UANL

La delta endotoxina de Bacillus thuringiensis GM-2

Tesis (Maestría en Ciencias, con especialidad en Microbio logía). U.A.N.L. Facultad de Ciencias Biológicas

Desarrollo de un medio de cultivo a base de subproductos agroindustriales para la producción de delta-endotoxina de B. thuringiensis VAR. israelensis H-14 [por] Ma. Guadalupe Maldonado Blanco

Tesis (Maestría en Ciencias con Especialidad en Microbiología) U.A.N.L. Facultad de Ciencias Biológicas

Modulation of Oxytocin Receptors in Right Ventricular Hypertrophy

L’hypertension pulmonaire (HP) est une maladie dont l’étiologie est inconnue et qui entraîne ultimement une défaillance du ventricule droit (VD) et le décès. L’HP peut être induite chez le rat par la la monocrotaline (MCT), un alcaloïde pyrrolizidique extrait de la plante Crotalaria Spectabilis, causant des lésions à l’endothélium des artères pulmonaires, menant à un épaississement de ces dernières et à une augmentation de la résistance vasculaire. Ceci à pour conséquence de causer une hypertrophie du VD, de l’inflammation, une dysfonction endothéliale NO-dépendante des artères coronariennes et une augmentation des peptides natriurétiques circulants. Objectif: Nous avons testé l’hypothèse selon laquelle l’étiopathologie de l’HP impliquerait le récepteur à ocytocine (OTR) dû à son implication fonctionnelle avec les cytokines inflammatoires et la libération du peptide natriurétique atrial (ANP) et du NO. Méthodes: Des rats mâles Sprague-Dawley pesant 220-250g reçurent une seule injection sous-cutanée de MCT (60 mg/kg). 6 à 7 semaines (46±1 jours) suivant l’injection, les rats furent sacrifiés et l’expression génique et protéique fut déterminée par PCR en temps réel et par western blot, respectivement, dans le VD et le ventricule gauche (VG) Résultats: Les rats traités au MCT démontrèrent une augmentation significative du VD. Une hypertrophie du VD était évidente puisque le ratio du VD sur le VG ainsi que le poids du septum étaient près de 77% plus élevés chez les rats traités au MCT que chez les rats contrôles. Le traitement au MCT augmenta l’expression génique d’ANP (3.7-fois dans le VG et 8-fois dans le VD) ainisi que le NP du cerveau (2.7-fois dans le VG et 10-fois dans le VD). Les transcrits de trois récepteurs de NP augmentèrent significativement (0.3-2 fois) seulement dans le VD. L’expression protéique de la NO synthase (iNOS) fut également augmentée de façon sélective dans le VD. Par contre, les transcripts de NOS endothéliale et de NOS neuronale étaient plus élevés (0.5-2 fold) dans le VG. L’ARNm et l’expression protéique d’OTR furent diminués de 50% dans le VD, tandis qu’une augmentation de l’expression des cytokines IL-1β and IL-6 fut observée. L’ARNm de Nab1, un marqueur d’hypertrophie pathologique, fut augmentée de deux-fois dans le VD. Conclusion: L’augmentation d’expression génique de NP dans le VD des rats traités au MCT est associée à une augmentation des transcripts du récepteur NP, suggérant une action locale de NP dans le VD durant l’HP. L’expression d’OTR est atténuée dans le VD, possiblement par des cytokines inflammatoires puisque le promoteur du gène de l’OTR contient de multiples éléments de réponse aux interleukines. Diminuer l’expression d’OTR dans le VD durant l’hypertension pulmonaire pourrait influencer de manière positive la fonction cardiaque car l’OTR régule la contractilité et le rythme cardiaque. Mots clés: hypertension pulmonaire, hypertrophie du ventricule droit monocrotaline, récepteur à ocytocine, inflammation, peptides natriurétiques.

Étiopathogenèse de la scoliose idiopathique de l'adolescent : implication de la mélatonine et de l'ostéopontine

La scoliose idiopathique de l’adolescent (SIA) est une maladie dont la cause est encore inconnue, et qui génère des déformations complexes du rachis, du thorax et du bassin. La prévalence est de 4% dans la population adolescente au Québec. Cette pathologie affecte surtout les filles durant leur poussée de croissance pubertaire. Parmi plusieurs hypothèses émises, l’hypothèse neuroendocrinienne, impliquant une déficience en mélatonine comme agent étiologique de la SIA a suscité beaucoup d’intérêt. Cette hypothèse découle du fait que l’ablation de la glande pinéale chez le poulet produit une scoliose ressemblant sous plusieurs aspects à la pathologie humaine. La pertinence biologique de la mélatonine dans la scoliose est controversée, étant donné que la majorité des études chez l’homme n’ont pu mettre en évidence une diminution significative des niveaux de mélatonine circulante chez les patients scoliotiques. Nous avons démontré un dysfonctionnement dans la signalisation de la mélatonine au niveau des tissus musculo-squelettiques chez une série de patients atteints de SIA (Moreau & coll. 2004). Nous avons confirmé ce défaut chez un plus grand nombre de patients ainsi qu’en utilisant une nouvelle technologie (spectroscopie cellulaire diélectrique) n’ayant pas recours à un prétraitement des cellules donnant ainsi des résultats plus précis. Cette technique a montré la présence des mêmes groupes fonctionnels identifiés auparavant par la technique d’AMPc. Le dysfonctionnement de la signalisation de la mélatonine est dû à une phosphorylation accrue des protéines G inhibitrices. Ce défaut pourrait être causé par un déséquilibre de l’activité des kinases et phosphatases capables de réguler la phosphorylation des protéines Gi. Parmi ces kinases, PKCd a suscité initialement notre intérêt vu qu’elle peut phosphoryler les protéines Gi. Nous avons démontré que cette kinase interagit avec le récepteur de la mélatonine MT2 et que cette interaction varie selon le groupe fonctionnel auquel un patient SIA appartient. Par la suite nos travaux se sont dirigés vers la découverte d’effecteurs cellulaires régulés par la mélatonine et plus spécifiquement l’ostéopontine (OPN), compte tenu de son rôle présumé comme mécanorécepteur et dans certaines structures jouant un rôle dans la proprioception, le contrôle postural et la fonction vestibulaire. L’OPN a été identifiée initialement par sa surexpression au niveau protéique et de l’ARNm dans la musculature paraspinale uniquement chez les poulets scoliotiques. Nous avons également utilisé un autre modèle animal, la souris C57Bl/6 naturellement déficiente en mélatonine. Nous avons généré des souris bipèdes en amputant les membres antérieurs de souris OPN KO, des souris CD44 KO ainsi que des souris contrôles C57Bl/6. Nos résultats ont montré qu’aucune souris OPN KO (n=50) ou CD44 KO (n=60) ne développe la maladie, contrairement aux souris contrôles C57Bl/6 (n=50) dont 45% deviennent scoliotiques. Ces résultats nous ont poussés à investiguer le rôle de cette protéine dans l’étiopathogenèse de la maladie chez l’humain. Nos résultats ont montré une augmentation des niveaux circulants d’OPN chez les patients atteints de la SIA et que l’élevation en OPN corrélait avec la sévérité de la maladie. Nos études chez les enfants asymptomatiques nés de parents scoliotiques et qui sont plus à risque de développer la maladie ont aussi démontré des différences significatives au niveau des concentrations en OPN en comparaison avec les sujets sains. En effet, plusieurs enfants à risque présentaient des niveaux d’OPN supérieurs à 800ng/ml suggérant un plus grand risque de développer une scoliose indiquant aussi que l’augmentation des niveaux en OPN précède le début de la maladie.