Effect of chronic ethanol exposure on rat ventilatory responses to hypoxia and hypercapnia

OBJECTIVE: The effect of chronic ethanol exposure on chemoreflexes has not been extensively studied in experimental animals. Therefore, this study tested the hypothesis that known ethanol-induced autonomic, neuroendocrine and cardiovascular changes coincide with increased chemoreflex sensitivity, as indicated by increased ventilatory responses to hypoxia and hypercapnia. METHODS: Male Wistar rats were subjected to increasing ethanol concentrations in their drinking water (first week: 5% v/v, second week: 10% v/v, third and fourth weeks: 20% v/v). At the end of each week of ethanol exposure, ventilatory parameters were measured under basal conditions and in response to hypoxia (evaluation of peripheral chemoreflex sensitivity) and hypercapnia (evaluation of central chemoreflex sensitivity). RESULTS: Decreased respiratory frequency was observed in rats exposed to ethanol from the first until the fourth week, whereas minute ventilation remained unchanged. Moreover, we observed an increased tidal volume in the second through the fourth week of exposure. The minute ventilation responses to hypoxia were attenuated in the first through the third week but remained unchanged during the last week. The respiratory frequency responses to hypoxia in ethanol-exposed rats were attenuated in the second through the third week but remained unchanged in the first and fourth weeks. There was no significant change in tidal volume responses to hypoxia. With regard to hypercapnic responses, no significant changes in ventilatory parameters were observed. CONCLUSIONS: Our data are consistent with the notion that chronic ethanol exposure does not increase peripheral or central chemoreflex sensitivity

Relatório de estágio

Relatório de estágio - Mestrado em Ensino da MúsicaRésumé-Section I - En septembre 2012, l’auteur a été engagé comme professeur au Conservatoire à Rayonnement Départemental du Choletais en France et a pris la classe de cor constituée de 25 élèves en charge. Dans un premier temps, l’auteur présente le projet pédagogique établi pour cette classe. Il répond aux exigences liées à son cadre d’emploi et tient compte des con naissances académiques acquises lors de sa formation à l’École Supérieure de Musique de Lisbonne et à l’École Supérieure d’Éducation. Dans un second temps, lors d’une description et d’une analyse de la mise en place de ce projet pédagogique pour l’ensemble de la classe, il aborde les sujets de l’enseignement adapté aux élèves déficients, l’enseignement aux adultes et de la transversalité des enseignements. Finalement est analysé, sur la base de ce projet pédagogique, le cas d'un élève de chaque cycle d'enseignement classique.Résumé-Section II - Depuis l’abaissement de l’âge d’entrée en 1er cycle dans l’enseignement spécialisé de la musique décrété par le ministère de la Culture dans les schémas d’orientation pédagogique des 20 dernières années, les cors standards doubles utilisés jusqu’à présent représentent de par leur poids un obstacle à l’apprentissage. En 1981, suite à une formation de 3 ans comme thérapeute de technique Alexander, le corniste anglais Pip Eastop conçoit un pied-support qui lui permet de jouer du cor tout en respectant "le bon usage de soi". Cette étude se concentre sur ce pied-support et cherche à définir s’il est possible de le considérer comme un outil ergonomiquement valide pour l’acquisition des compétences fondamentales présentées en 1ère section. Sont présentés un historique de l'évolution du poids du cor, les solutions envisageables pour l'enseignement du cor, une étude empirique basée sur des questionnaires effectuée au sein de la classe de cor du Conservatoire à Rayonnement départemental du Choletais et pour conclure est abordée en discussion finale les conséquences de l'ergonomie sur l'enseignement spécialisé de la musique.Abstract-Section I - In September 2012, the author was taken on as a French horn teacher at the "Conservatoire à Rayonnement Départemental du Choletais" in France, taking over the corresponding class of 25 students. Firstly, the author presents the educational project designed specifically for this class. It meets the requirements of his job description, and reflects the academic knowledge acquired during his training at the "Escola Superior de Musica de Lisboa," as well as at the "Escola Superior da Educacao." Secondly, by describing and analysing the implementation of this educational project for the whole class, the author examines issues regarding the education of "special-needs" students, adult education and the transversatily of musical teaching syllabuses. Finally, based on the educational project, the author analyses the individual case of a student from each of the classical cycle.Abstract Section II - Since the lowering of the age of entry to the first cycle in special, musical education in a decree enacted over the past twenty years by the Ministry of Culture, the double- standard French horns used so far have been a barrier to learning, simply through their sheer weight. In 1981, after three years training as a therapist using the "Alexander Method," the English French horn player, Pip Eastop, designed a hornstick which enabled him to play while maintaining "the proper use of the self." This study focuses on the hornstick, and attempts to ascertain whether it is possible for the hornstick to be considered as an ergonomically-valid tool for the acquisition of the basic skills presented in the first section. The author presents the history of the evolution of the weight of the French horn, some possible solutions for teaching the French horn, as well as an empirical study based on questionnaires completed by members of the French horn classes at the "Conservatoire à Rayonnement Département du Choletais," before concluding by examining the ergonomic consequences on teaching methods.N/

Locus coeruleus is a central chemoreceptive site in toads

The locus coeruleus (LC) has been suggested as a CO2 chemoreceptor site in mammals. This nucleus is a mesencephalic structure of the amphibian brain and is probably homologous to the LC in mammals. There are no data available for the role of LC in the central chemoreception of amphibians. Thus the present study was designed to investigate whether LC of toads (Bufo schneideri) is a CO2/H+ chemoreceptor site. Fos immunoreactivity was used to verify whether the nucleus is activated by hypercarbia (5% CO2 in air). In addition, we assessed the role of noradrenergic LC neurons on respiratory and cardiovascular responses to hypercarbia by using 6-hydroxydopamine lesion. To further explore the role of LC in central chemosensitivity, we examined the effects of microinjection of solutions with different pH values (7.2, 7.4, 7.6, 7.8, and 8.0) into the nucleus. Our main findings were that 1) a marked increase in c-fos-positive cells in the LC was induced after 3 h of breathing a hypercarbic gas mixture; 2) chemical lesions in the LC attenuated the increase of the ventilatory response to hypercarbia but did not affect ventilation under resting conditions; and 3) microinjection with acid solutions (pH = 7.2, 7.4, and 7.6) into the LC elicited an increased ventilation, indicating that the LC of toads participates in the central chemoreception

Validity of 5 year old children’s oral hygiene pattern referred by mothers

OBJETIVO: Determinar a validade de perguntas freqüentemente utilizadas em estudos epidemiológicos sobre higiene bucal de crianças e compará-la segundo renda familiar e escolaridade da mãe. MÉTODOS: Foram analisadas 1.122 crianças participantes do sub estudo de saúde bucal de 2009 da Coorte de Nascimentos de Pelotas, RS, 2004. As crianças foram examinadas e suas mães entrevistadas no domicílio. O padrão ouro da condição de higiene bucal foi avaliado por meio do Índice de Higiene Oral Simplificado e a partir do seu escore total o desfecho foi dicotomizado em: placa dental ausente (escore total = 0) e presente (escore total ≥ 1). As perguntas testadas sobre o padrão de higiene bucal das crianças foram formuladas às mães e incluíram: freqüência diária de escovação, escovação antes de dormir e a combinação dessas duas (higiene bucal), com suas opções de resposta dicotomizadas em regular e irregular. A validade foi determinada por meio do cálculo dos valores percentuais e respectivos intervalos de 95% de confiança de sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo. RESULTADOS: A prevalência de placa dental foi 37,0%. Os valores de sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo foram, respectivamente: 29,6%, 82,5%, 49,8% e 66,6%, para freqüência de escovação diária irregular; 41,8%, 64,6%, 40,9% e 65,5%, para escovação antes de dormir irregular; 48,8%, 60,8%, 42,2% e 67,0%, para higiene bucal irregular. A validade do padrão de higiene bucal variou conforme o nível de renda familiar e a escolaridade da mãe, e a sensibilidade e o valor preditivo positivo foram maiores entre os indivíduos com menor renda familiar e com mães menos escolarizadas e o oposto, para a especificidade e o valor preditivo negativo.CONCLUSÕES: Perguntas sobre higiene bucal respondidas pelas mães de crianças não são boas substitutas do padrão real de higiene bucal medido por meio do exame clínico bucal de placa dental

Respiratory Chemoreceptor Function in Vertebrates—Comparative and Evolutionary Aspects

The sensing of blood gas tensions and/or pH is an evolutionarily conserved, homeostatic mechanism, observable in almost all species studied from invertebrates to man. In vertebrates, a shift from the peripheral O2-oriented sensing in fish, to the central CO2/pH sensing in most tetrapods reflects the specific behavioral requirements of these two groups whereby, in teleost fish, a highly O2-oriented control of breathing matches the ever-changing and low oxygen levels in water, whilst the transition to air-breathing increased the importance of acid–base regulation and O2-related drive, although retained, became relatively less important. The South American lungfish and tetrapods are probably sister groups, a conclusion backed up by many similar features of respiratory control. For example, the relative roles of peripheral and central chemoreceptors are present both in the lungfish and in land vertebrates. In both groups, the central CO2/pH receptors dominate the ventilatory response to hypercarbia (60–80%), while the peripheral CO2/pH receptors account for 20–30%. Some basic components of respiratory control have changed little during evolution. This review presents studies that reflect the current trends in the field of chemoreceptor function, and several laboratories are involved. An exhaustive review on the previous literature, however, is beyond the intended scope of the article. Rather, we present examples of current trends in respiratory function in vertebrates, ranging from fish to humans, and focus on both O2 sensing and CO2 sensing. As well, we consider the impact of chronic levels of hypoxia—a physiological condition in fish and in land vertebrates resident at high elevations or suffering from one of the many cardiorespiratory disease states that predispose an animal to impaired ventilation or cardiac output. This provides a basis for a comparative physiology that is informative about the evolution of respiratory functions in vertebrates and about human disease. Currently, most detail is known for mammals, for which molecular biology and respiratory physiology have combined in the discovery of the mechanisms underlying the responses of respiratory chemoreceptors. Our review includes new data on nonmammalian vertebrates, which stresses that some chemoreceptor sites are of ancient origin

Serotonergic neurons in the nucleus raphé obscurus are not involved in the ventilatory and thermoregulatory responses to hypoxia in adult rats

The medullary raphé is an important component of the central respiratory network, playing a key role in CO2 central chemoreception. However, its participation in hypoxic ventilatory responses is less understood. In the present study, we assessed the role of nucleus raphé obscurus (ROb), and specifically 5-HT neurons confined in the ROb, on ventilatory and thermoregulatory responses to hypoxia. Chemical lesions of the ROb were performed using either ibotenic acid (non-specific lesion; control animals received PBS) or anti-SERT-SAP (5-HT specific lesion; control animals received IgG-SAP). Ventilation (VE; whole body plethysmograph) and body temperature (Tb; data loggers) were measured during normoxia (21% O2, N2 balance) and hypoxia exposure (7% O2, N2 balance, 1h) in conscious adult rats. Ibotenic acid or anti-SERT-SAP-induced lesions did not affect baseline values of VE and Tb. Similarly, both lesion procedures did not alter the ventilatory or thermoregulatory responses to hypoxia. Although evidence in the literature suggests a role of the rostral medullary raphé in hypoxic ventilatory responses, under the present experimental conditions our data indicate that caudal medullary raphé (ROb) and its 5-HT neurons neither participate in the tonic maintenance of breathing nor in the ventilatory and thermal responses to hypoxia. © 2013 Elsevier B.V