Physiological noise in human cerebellar fMRI.

OBJECTIVES: To compare physiological noise contributions in cerebellar and cerebral regions of interest in high-resolution functional magnetic resonance imaging (fMRI) data acquired at 7T, to estimate the need for physiological noise removal in cerebellar fMRI. MATERIALS AND METHODS: Signal fluctuations in high resolution (1 mm isotropic) 7T fMRI data were attributed to one of the following categories: task-induced BOLD changes, slow drift, signal changes correlated with the cardiac and respiratory cycles, signal changes related to the cardiac rate and respiratory volume per unit of time or other. [Formula: see text] values for all categories were compared across regions of interest. RESULTS: In this high-resolution data, signal fluctuations related to the phase of the cardiac cycle and cardiac rate were shown to be significant, but comparable between cerebellar and cerebral regions of interest. However, respiratory related signal fluctuations were increased in the cerebellar regions, with explained variances that were up to 80 % higher than for the primary motor cortex region. CONCLUSION: Even at a millimetre spatial resolution, significant correlations with both cardiac and respiratory RETROICOR components were found in all healthy volunteer data. Therefore, physiological noise correction is highly likely to improve the temporal signal-to-noise ratio (SNR) for cerebellar fMRI at 7T, even at high spatial resolution.

Imagerie par DXA: le couteau suisse multifonction [DXA imaging: the multifunction Swiss army knife?].

Les importants progrès dans la qualité et la résolution des images obtenues par «absorptiométrie biphotonique à rayons X» ou DXA ont amélioré certaines modalités existantes et favorisé le développement de nouvelles fonctions permettant d'affiner de manière significative la prise en charge de nos patients dans diverses pathologies. On peut par exemple améliorer la prédiction du risque fracturaire par l'analyse indirecte de la micro et de la macroarchitecture osseuse, rechercher les marqueurs de pathologies associées (recherche de fractures vertébrales ou de fractures fémorales atypiques), ou évaluer le statut métabolique par la mesure de la composition corporelle. Avec les appareils DXA les plus performants, on pourra bientôt déterminer l'âge osseux, estimer le risque cardiovasculaire (par la mesure de la calcification de l'aorte abdominale), ou prédire la progression de l'arthrose articulaire et son évolution après la prise en charge chirurgicale dans la routine clinique. The significant progress on the quality and resolution of the images obtained by "Dual X-ray Absorptiometry" or DXA has permitted on one hand to improve some existing features and on the other to develop new ones, significantly refining the care of our patients in various pathologies. For example, by improving the prediction of fracture risk by indirect analysis of micro- and macro-architecture of the bone, by looking for markers of associated bone diseases (research vertebral fractures or atypical femoral fractures), or by assessing the metabolic status by the measurement of body composition. With the best performing DXA devices we will soon be able, in clinical routine, to determine bone age, to estimate cardiovascular risk (by measuring the calcification of the abdominal aorta) or to predict the progression of joint osteoarthritis and its evolution after surgical management.

Functional magnetic resonance imaging in oncology: state of the art

In the investigation of tumors with conventional magnetic resonance imaging, both quantitative characteristics, such as size, edema, necrosis, and presence of metastases, and qualitative characteristics, such as contrast enhancement degree, are taken into consideration. However, changes in cell metabolism and tissue physiology which precede morphological changes cannot be detected by the conventional technique. The development of new magnetic resonance imaging techniques has enabled the functional assessment of the structures in order to obtain information on the different physiological processes of the tumor microenvironment, such as oxygenation levels, cellularity and vascularity. The detailed morphological study in association with the new functional imaging techniques allows for an appropriate approach to cancer patients, including the phases of diagnosis, staging, response evaluation and follow-up, with a positive impact on their quality of life and survival rate.

Uma visão da química bioinorgânica medicinal

Metals play a vital role in human and plant physiology and important research is directed towards exploring the interrelated mechanisms that govern their interactions with biomolecules. Bioinorganic medicinal chemistry studies the functions, processing, storage and applications of metal ions and their complexes in biological systems. This paper presents a brief discussion about on interactions of metals with biomolecules that determine their intracellular accumulation, where metal ions may fulfill essential functions in cellular metabolism or, in certain cases, exert toxic effects towards cells.

Reencontro de Balanoglossus gigas Fr. Muller no litoral brasileiro

Re-finding of Balanoglossus gigas FR. MUULLER on the brasilian sea shore. Balanoglossus gigas, the giant Enteropneusta, has been described for the first time by Fritz Muller in his notes collected and published by Dr. HERMANN VON IHERING (1898, pg. 35). FR. MULLER found the Balanoglossus on the coats of the State of Santa Catarina in 1884. Once again in 1885 several specimens of that animal were captured by FR. MULLER in the same place. Since that time up to now no references on the occurrence of this animal have been found in the zoological bibliography. During the spring of 1948 Prof. W. BESNARD, Director of he Instituto Paulista de Oceanografia saw some signals indicating the existence of Balanoglossus at the beach of São Sebastião, State of São Paulo. From 1948 to now several attempts have been made to catch the animal alive and complete. On the last September during a shorts visit to the beach of São Sebastião one Balanoglossus was captured and brought to the Department of General and Animal Physiology in good conditions. The animal measured 1.80 m in length. It seems to be the largest Balanoglossus known. According to the descriptions of SPENGEL (1893, pg. 158), and VAN DER HORST (1939) pg. 717) it was possible to identify this Enteropneusta as Balanoglossus gigas FR. MULLER, refound at the Brazilian coast sixty six years after its discovery by FR. MÜLLER.

Refluxo gastroesofágico no paciente encefalopata

We intend to discuss the main controversies involved in the diagnosis of gastroesophageal reflux and the necessity of a special method to feed severe neurologically impaired children, considering the implications of those circumstances in Brazilian families. Modern literature was reviewed, relating to diagnostic methodologies and their limitations, surgical methods, complications and resolution of the symptoms. There are controversies not yet solved about alimentary problems in the neurologically impaired children, specially concerning the presence of gastroesophageal reflux and respiratory disease. Familiar and social consequences of both primary neurological and secondary respiratory and nutricional disease are essential to consider. The incidence of gastroesophageal disease is extremely high in neurologically impaired children, with a high morbimortality and frequent respiratory manifestations. Surgical treatment offers high risks in case of associated complex congenital cardiac malformations. Alimentary gastrostomy and fundoplication offer good results concerning the incidence of respiratory problems and less hospitalizations for those patients.

Lactated Ringer's solution or 0.9% sodium chloride as fluid therapy in pigeons (Columba livia) submitted to humerus osteosynthesis

The study aimed to compare the effects of intraosseous infusion of lactated Ringer's and 0.9% sodium chloride solutions on the electrolytes and acid-base balance in pigeons submitted to humerus osteosynthesis. Eighteen pigeons were undergoing to isoflurane anesthesia by an avalvular circuit system. They were randomly assigned into two groups (n=9) receiving lactated Ringer's solution (LR) or 0.9% sodium chloride (SC), in a continuous infusion rate of 20mL/kg/h, by using an intraosseous catheter into the tibiotarsus during 60-minute anesthetic procedure. Heart rate (HR), and respiratory rate (RR) were measured every 10 min. Venous blood samples were collected at 0, 30 and 60 minutes to analyze blood pH, PvCO2, HCO3 -, Na+ and K+. Blood gases and electrolytes showed respiratory acidosis in both groups during induction, under physical restraint. This acidosis was evidenced by a decrease of pH since 0 min, associated with a compensatory response, observed by increasing of HCO3 - concentration, at 30 and 60 min. It was not observed any changes on Na+ and K+ serum concentrations. According to the results, there is no reason for choosing one of the two solutions, and it could be concluded that both fluid therapy solutions do not promote any impact on acid-base balance and electrolyte concentrations in pigeons submitted to humerus osteosynthesis.

Systemic acanthamoebiasis associated with canine distemper in dogs in the semiarid region of Paraíba, Brazil

Infections by free-living amoebae can cause systemic disease in animals and humans. We describe the epidemiological, clinical and pathological aspects of disseminated acanthamoebiasis associated with canine distemper in three dogs of the semiarid region of Paraíba, Northeastern Brazil. Affected dogs developed progressive neurological and respiratory signs that progressed to death within in two to 20 days. Gross lesions were irregular and with yellow-reddish nodules randomly distributed in the lungs, heart, kidneys, spleen, lymph nodes, adrenals, and intestine. One dog had foci of malacia in the parietal cortex and another one in nucleus of brain basis. Histologically, pyogranulomas with areas of necrosis and hemorrhage in all organs affected were observed, associated with myriads of intralesional amoebic trophozoites. All three cases were concomitant canine distemper, that possibly triggered immunosuppression in the dogs. The diagnosis was performed through microscopic findings of infection by free-living amoebae and confirmed Acanthamoeba sp. by immunohistochemistry

Computerized invasive measurement of time-dependent intraocular pressure

Several methods have been described to measure intraocular pressure (IOP) in clinical and research situations. However, the measurement of time varying IOP with high accuracy, mainly in situations that alter corneal properties, has not been reported until now. The present report describes a computerized system capable of recording the transitory variability of IOP, which is sufficiently sensitive to reliably measure ocular pulse peak-to-peak values. We also describe its characteristics and discuss its applicability to research and clinical studies. The device consists of a pressure transducer, a signal conditioning unit and an analog-to-digital converter coupled to a video acquisition board. A modified Cairns trabeculectomy was performed in 9 Oryctolagus cuniculus rabbits to obtain changes in IOP decay parameters and to evaluate the utility and sensitivity of the recording system. The device was effective for the study of kinetic parameters of IOP, such as decay pattern and ocular pulse waves due to cardiac and respiratory cycle rhythm. In addition, there was a significant increase of IOP versus time curve derivative when pre- and post-trabeculectomy recordings were compared. The present procedure excludes corneal thickness and error related to individual operator ability. Clinical complications due to saline infusion and pressure overload were not observed during biomicroscopic evaluation. Among the disadvantages of the procedure are the requirement of anesthesia and the use in acute recordings rather than chronic protocols. Finally, the method described may provide a reliable alternative for the study of ocular pressure dynamic alterations in man and may facilitate the investigation of the pathogenesis of glaucoma.

Molecular analysis of the bovine coronavirus S1 gene by direct sequencing of diarrheic fecal specimens

Bovine coronavirus (BCoV) causes severe diarrhea in newborn calves, is associated with winter dysentery in adult cattle and respiratory infections in calves and feedlot cattle. The BCoV S protein plays a fundamental role in viral attachment and entry into the host cell, and is cleaved into two subunits termed S1 (amino terminal) and S2 (carboxy terminal). The present study describes a strategy for the sequencing of the BCoV S1 gene directly from fecal diarrheic specimens that were previously identified as BCoV positive by RT-PCR assay for N gene detection. A consensus sequence of 2681 nucleotides was obtained through direct sequencing of seven overlapping PCR fragments of the S gene. The samples did not undergo cell culture passage prior to PCR amplification and sequencing. The structural analysis was based on the genomic differences between Brazilian strains and other known BCoV from different geographical regions. The phylogenetic analysis of the entire S1 gene showed that the BCoV Brazilian strains were more distant from the Mebus strain (97.8% identity for nucleotides and 96.8% identity for amino acids) and more similar to the BCoV-ENT strain (98.7% for nucleotides and 98.7% for amino acids). Based on the phylogenetic analysis of the hypervariable region of the S1 subunit, these strains clustered with the American (BCoV-ENT, 182NS) and Canadian (BCQ20, BCQ2070, BCQ9, BCQ571, BCQ1523) calf diarrhea and the Canadian winter dysentery (BCQ7373, BCQ2590) strains, but clustered on a separate branch of the Korean and respiratory BCoV strains. The BCoV strains of the present study were not clustered in the same branch of previously published Brazilian strains (AY606193, AY606194). These data agree with the genealogical construction and suggest that at least two different BCoV strains are circulating in Brazil.

Effects of acute administration of selective serotonin reuptake inhibitors on sympathetic nerve activity

Serotonergic mechanisms have an important function in the central control of circulation. Here, the acute effects of three selective serotonin (5-HT) reuptake inhibitors (SSRIs) on autonomic and cardiorespiratory variables were measured in rats. Although SSRIs require 2-3 weeks to achieve their full antidepressant effects, it has been shown that they cause an immediate inhibition of 5-HT reuptake. Seventy male Wistar rats were anesthetized with urethane and instrumented to record blood pressure, heart rate, renal sympathetic nerve activity (RSNA), and respiratory frequency. At lower doses, the acute cardiovascular effects of fluoxetine, paroxetine and sertraline administered intravenously were insignificant and variable. At middle and higher doses, a general pattern was observed, with significant reductions in sympathetic nerve activity. At 10 min, fluoxetine (3 and 10 mg/kg) reduced RSNA by -33±4.7 and -31±5.4%, respectively, without changes in blood pressure; 3 and 10 mg/kg paroxetine reduced RSNA by -35±5.4 and -31±5.5%, respectively, with an increase in blood pressure +26.3±2.5; 3 mg/kg sertraline reduced RSNA by -59.4±8.6%, without changes in blood pressure. Sympathoinhibition began 5 min after injection and lasted approximately 30 min. For fluoxetine and sertraline, but not paroxetine, there was a reduction in heart rate that was nearly parallel to the sympathoinhibition. The effect of these drugs on the other variables was insignificant. In conclusion, acute peripheral administration of SSRIs caused early autonomic cardiovascular effects, particularly sympathoinhibition, as measured by RSNA. Although a peripheral action cannot be ruled out, such effects are presumably mostly central.

Factors affecting DNA uptake by mammalian cells

The ability to introduce DNA and express custom DNA sequences in bacteria opened the door for improvements in a large number of fields including agriculture, pharmacology, medicine, nutrition, etc. The ability to introduce foreign DNA sequences into mammalian cells in an efficient manner would have a large impact on therapeutic applications especially gene therapy. The methods in use today suffer from low efficiencies and sometimes toxicity. In this work a number of factors were evaluated for their effect onONA uptake efficiency. The factors studied included exposure to sublethal concentration of hydrogen peroxide which have been show to lead to destabilisation ofthe lysosomes. These exposures have proven to be very toxic to cells when combined with either the calcium phosphate or the lipofectAMINE® transfection methods. Another factor evaluated was exposure to Electro-Magnetic Fields (EMF). This was fuelled by the fact that EMF have been shown to mediate a number of effects on cell structure and/or physiology. EMF exposure by itself was not sufficient to induce the cells to pick up the DNA, therefore its effect on calcium phosphate and lipofectAMINE® was tested. Although some positive results were obtained, the variability of these results exceeded by far any observed enhancements which discouraged any further work on EMF. Also tested was the possible effect the presence of the cytomegalovirus (CMV) sequence might have on DNA uptake (based on previous results in this lab). It was found that the presence ofCMV in the DNA sequence does not enhance uptake or slow down degradation of the internalised DNA. The final factor tested was the effect of basic amino acids on transfection efficiency. It was found that arginine can enhance DNA uptake by about 170% v/ith calcium phosphate and about 200% with LipofectAMINE®. A model was proposed to explain the effect of arginine as well as the lack of effect from other amino acids.

Étude de la diversité génétique d’isolats québécois de Mycoplasma hyopneumoniae provenant d’infections simples ou mixtes et caractérisation de leur sensibilité aux antimicrobiens

Mycoplasma hyopneumoniae est l’agent causal de la pneumonie enzootique. On le retrouve dans plusieurs élevages de porcs à travers le monde. Même si ce micro-organisme est présent dans plusieurs troupeaux canadiens, peu d’informations sont présentement disponibles sur les isolats québécois. Un total de 160 poumons de porcs possédant des lésions de pneumonie ont été récupérés à l’abattoir, mis en culture et testés par PCR pour M. hyopneumoniae et Mycoplasma hyorhinis. D’autres pathogènes bactériens communs du porc et les virus du syndrome reproducteur et respiratoire porcin (VSRRP), de l’influenza et le circovirus porcin de type 2 (CVP2) ont été également testés. Quatre-vingt-dix pourcent des échantillons étaient positifs pour M. hyopneumoniae et 5.6% l’étaient seulement pour M. hyorhinis. Dans ces échantillons positifs pour M. hyopneumoniae, la concentration de ce mycoplasme variait de 1.17 x 105 à 3.37 x 109 génomes/mL. Vingt-cinq poumons positifs en culture ou par PCR en temps réel pour M. hyopneumoniae ont été sélectionnés, parmi ceux-ci 10 étaient en coinfection avec Pasteurella multocida, 12 avec Streptococcus suis, 9 avec CVP2 et 2 avec le VSRRP. Les analyses des nombres variables de répétitions en tandem à de multiples loci (MLVA) et PCR-polymorphisme de longueur de fragments de restriction (PCR-RFLP) de M. hyopneumoniae ont démontré une forte diversité des isolats de terrain. Par contre, il semble y avoir plus d’homogénéité à l’intérieur d’un même élevage. L’analyse MLVA a également démontré que près de la moitié des isolats possédaient moins de 55% d’homologie avec les souches vaccinales et de référence utilisées dans la présente étude. L’absence d’amplification du locus 1 de M. hyopneumoniae en MLVA a été significativement associée à une baisse de la concentration de bactérie et de la sévérité des lésions. Pour tous les isolats de M. hyopneumoniae, des concentrations minimales inhibitrices (CMI) de faibles à intermédiaires ont été obtenues envers tous les antimicrobiens testés. Les isolats possédant des CMI intermédiaires envers les tétracyclines, les macrolides et les lincosamides ont été testés pour la présence des gènes de résistance tetM, ermB et pour des mutations ponctuelles dans les gènes des protéines L4, L22 et de l’ARNr 23S. Aucun de ces gènes n’a été détecté mais la mutation ponctuelle G2057A a été identifiée. Cette mutation est responsable de la résistance intrinsèque de M. hyopneumoniae face aux macrolides à 14 carbones. Ces résultats indiquent qu’il ne semble pas y avoir de résistance acquise aux antimicrobiens parmi ces isolats. En conclusion, cette recherche a permis d’obtenir de nouvelles données scientifiques sur les isolats québécois de M. hyopneumoniae.

Sleep bruxism is associated with a rise in blood pressure

Objectifs : Le bruxisme survenant au cours du sommeil est un trouble du mouvement caractérisé par du grincement de dents et l’activité rythmique des muscles masticateurs (ARMM). Le bruxisme/ARMM est souvent associé à des mouvements du corps et des à éveils corticaux. Une séquence d’activation précède le ARMM/bruxisme. Ces événements incluent une augmentation des variables suivants : l’activité sympathique (-4 minutes), les activités encéphalographique (-4 second), le fréquence cardiaque, l’amplitude de la respiration (-1 second) et l’activité des muscle suprahyoïdiens (-0.8 second). La présente étude a examiné l’association entre le bruxisme et les changements de la pression artérielle. Méthodes: Dix sujets avec le bruxisme (5 hommes, 5 femmes, âge moyen = 26 ± 1,8) ont complétés 3 nuits de polysomnographie qui comprenait l'enregistrement non invasive de la pression artérielle. La première nuit a servi de dépistage et d’habituation au laboratoire. L'analyse a été réalisée sur les deuxièmes et troisièmes nuits enregistrements. Seuls les épisodes de bruxisme isolés survenant au cours du stade 2 du sommeil ont été utilisés pour l’analyse, pour un total de 65 épisodes. Les mesures des pressions systolique et diastolique ont été prises 20 battements avant et 23 battements après l'apparition de chaque épisode bruxisme lors du sommeil. Les épisodes de bruxisme ont été classés comme suit: 1) bruxisme avec éveil cortical; 2) bruxisme avec mouvement du corps (MC), 3) bruxisme avec éveil cortical et MC. Une quatrième catégorie, bruxisme seul, a également été analysée, mais utilisée comme donnée préliminaire puisque la catégorie se composait de seulement 4 épisodes de bruxisme. Résultats: Les deux pressions systolique et diastolique ont augmenté avec les épisodes de bruxisme. Cette augmentation a été statistiquement significative pour la pression systolique et diastolique pour les épisodes de bruxisme avec éveil cortical et/ou MC (p ≤ 0,05). L’augmentation moyenne de la pression (systolique / diastolique ± SE) a été : 28,4 ± 2,4/13,2 ± 1,5 mm Hg pour le bruxisme avec éveil cortical; 30,7 ± 1,6/19.4 ± 2.3 mm Hg pour bruxisme avec MC; 26.4 ± 2,8 / 14,6 ± 2.0mm Hg pour bruxisme avec éveil cortical et MC; 22,9 ± 5,2/12,4 ± 3,3mm Hg pour les épisodes de bruxisme seuls. Conclusion: Le bruxisme du sommeil est associé à des hausses de la pression artérielle pendant le sommeil. Cette hausse est supérieure dans les épisodes de bruxisme associés à un éveil cortical et / ou MC, qui sont souvent associés avec les événements bruxisme. Ces résultats sont en accord avec nos observations antérieures, où le bruxisme est précédé par une augmentation de l'activité sympathique et de la tachycardie sinusale.