Prepubertal indicators of potential sperm-producing capacity in the beef bull

Study 1. An experiment was carried out to determine whether peripheral hormone concentrations quantified between 2 and 12 months (mo) were meaningfully correlated with testis size and number of Sertoli and germ cells in the yearling beef bull. Twenty four Angus bulls were treated monthly with GnRH (0.05 μg per Kg of body weight) and bled 1.5 and 3 hours (h) later. On the day before the GnRH challenge, three blood samples were taken at 1.5-h intervals to establish basal hormone concentrations. At 12 mo, all bulls were surgically castrated. Concentrations of FSH, LH, testosterone (T), androstenedione (δ4A) and 17β-estradiol (E2) were quantified by RIA and number of Sertoli cells per testis and quantitative aspects of spermatogenesis were determined. Analysis of regression and Pearson\u27s partial correlation were used to estimate the degree of association between hormone and testis data. Histology analysis revealed that 3 bulls had no spermatids and, therefore, were infertile. Yearling testis weight (TW) was related to GnRH-stimulated T at 3 mo (r = 0.48, p \u3c 0.05) and E2 and 2 and 4 mo (r = 0.40 and 0.45, p \u3c 0.10). Basal and GnRH-stimulated FSH quantified between 2 and 12 mo were correlated with TW (r = - 0.37, p \u3c 0.10 to - 0.71, p \u3c 0.01), number of Sertoli cells (r = nonsignificant, p \u3e 0.10 to r = -0.59, p \u3c 0.05) and number of round spermatids per testis (r = nonsignificant, p \u3e 0.10 to - 0.69, p \u3c 0.01). Also, FSH between 2 and 12 mo correlated with number of round spermatids per A1 spermatogonia (r = nonsignificant, p \u3e 0.10 to r = - 0.61, p \u3c 0.01), number of round spermatids per Sertoli cell (r=nonsignificant, p \u3e 0.10 to - 0.64, p \u3c 0.01) and percent of seminiferous tubules with round spermatids (r = nonsignificant, p \u3e 0.10 to r = - 0.63, p \u3c 0.01) in the 12-mo old testis. Regression analysis showed that FSH and E2 at 2 mo accounted for 45% of the variation in TW. Furthermore, significant variation in TW was accounted by FSFI and testis diameter at 6 mo (R2 = 0.57), FSH and testis diameter at 9 mo (R2 = 0.67) and FSH and body weight at 12 mo (R2 = 0.63). Thus, it appears that prepubertal testis size and FSH could be used as indicators of testicular development of yearling beef bulls. However, the inclusion of data from infertile bulls in the correlation and regression analysis may have generated biased results. Three cases of spermatogenic arrest were described in this study. Bull #250 had seminiferous tubules lined by Sertoli cells only and bull #345 had no germ cells that advanced beyond the A1 spermatogonia stage. Testes of these two bulls weighed 60% less than those of normal bulls (p \u3c 0.01). Concentrations of T and LH in bulls #250 and #345 were reduced at some ages (p \u3c 0.10). Spermatogenic arrest at the level of pachytene spermatocyte was detected in bull #389. Basal FSH and LH were higher in bull #389 than in normal bulls (p \u3c 0.05). Testes of this bull weighed 13% of those of normal bulls and secreted less T throughout the year (p \u3c 0.05). However, as in the cases of bulls #250 and #345, the decrease in T observed in bull#389 did not appear to be sufficient to interrupt germ cell development. Chromosomal abnormalities and/or deficiency in intratesticular factors may be the causes of infertility in these bulls. Study 2. The objective of this study was to determine whether concentrations of gonadotropins and steroids in 2- and 6-month old beef bulls were significantly correlated with testicular development and number of Sertoli cells at the age of 6 months (mo). At 2 mo, 15 crossbred bulls were treated with GnRH (5 μg) and bled 1.5, 3 and 4.5 hours (h) later. One day before the GnRH challenge, three basal samples were taken at 1.5-h intervals. At 6 mo, bulls received 1 mg of estradiol benzoate (E) and were treated with GnRH (10 pg) 12 h later. After 5 days, bulls received GnRH only (10 pg). In both cases, blood samples were taken 1.5, 3 and 4.5 h after GnRH and two basal samples were taken 1 h before the GnRH treatment. Bulls were castrated at 6 mo. Concentrations of FSH, LH, testosterone (T), androstenedione (δ4A) and 17β-estradiol (E2) were quantified by RIA. Number of Sertoli cells and A1 spermatogonia per testis and quantitative aspects of spermatogenesis were also estimated. Analysis of regression and Pearson\u27s partial correlation were used to estimate the degree of association between hormone and testis data. Results showed that testis weight at 6 mo (TW) was related to FSH at 2 mo (r = - 0,48 to - 0.62, p = 0.08 to 0.02). Also, concentrations of FSH at 2 mo was correlated with number of Sertoli cells (SC; r = - 0.50 to - 0.65, p = 0.07 to 0.01), A1 spermatogonia (Al; r = - 0.45 to - 0.58, p = 0.09 to 0.03) and number of seminiferous tubules with round spermatids (r = - 0.49 to - 0.60, p = 0.08 to 0.02). Regression analysis showed that FSH and body weight at 2 mo accounted for 30% and 72% of the variation in SC and TW in the 6-mo old bull. Concentrations of estradiol at 6 mo were related to SC (r = 0.62, p = 0.02). At 6 mo, GnRH-stimulated FSH and LH were respectively 2.5- and 3-fold higher when GnRH was given in combination with E than when GnRH was given alone. Correlation between FSH and SC was more pronounced after GnRH+E (r = -0.68, p = 0.008) than after GnRH only (r = - 0.63, p = 0.015). Regression modeling showed that FSH and body weight at 6 mo accounted for 48% of the variation in the population of Sertoli cells. Thus, concentrations of FSH at 2 and 6 mo of age appears to be reliable indicators of number of Sertoli cells and testicular development in the 6-mo beef bull. Study 3. This study was carried out to determine whether testis size, histology and hormone secretion at the developmental state at which concentrations of testosterone reached 1 ng/ml of serum were related to size of the testis and quantitative aspects of spermatogenesis in the yearling bull testis. Three basal blood samples (at 1.5-hour intervals) were taken from 28 Angus calves since the age of 15 weeks (wk). When concentrations of testosterone (T) reached 1 ng/ml, bulls were unilaterally castrated. On a monthly base, bulls received 0.05 pg of GnRH per Kg of body weight and were bled 1.5 and 3 hours later. At 54 wk, the second testis was excised. RJA\u27s were used to quantify FSH, LH, T, androstenedione (δ4A) and 17β-estradiol (E2) in blood samples. Number of Sertoli cells and quantitative aspects of spermatogenesis were estimated in both testes. Analysis of regression and Pearson\u27s partial correlation were used to estimate the degree of association between hormone and testicular development. Results showed that testis weight when T = 1 ng/ml (TWl) was correlated with testis weight (TW2; r = 0.58, p \u3c 0.01), and number of Sertoli cells and round spermatids per testis at 54 wk (r = 0.58, p \u3c 0.01). Also, TWl was related to number of spermatids per Sertoli cell (r = 0.41, p \u3c 0.05), and number of seminiferous tubules with elongate (STE) and mature (STM) spermatids (r = 0.47 and 0.52, respectively; p \u3c 0.05) in the second testis. However, neither STE nor STM were correlated with number of tubule sections with germ cells in the first testis (STGl). Testis diameter averaged between the ages of 30 and 44 wk (AVTD) and TW2 were correlated with AGEl (r = - 0.58 and - 0.42, p \u3c 0.01), TWl (r = 0.65 and 0.58, p \u3c 0.01) and STGl (r = 0.43 and 0.41, p \u3c 0.10). Regression analysis showed that AGEl and body weight when T = 1 ng/ml accounted for 41% of the variation in testis diameter between 30 and 44 wk. GnRH-stimulated FSH at 11 wk was related to STGl, TWl, TW2 and AVTD (r = - 0.42 to - 0.53, p \u3c 0.05). GnRH-stimulated T at 15 wk was related to TWl (r = 0.55, p \u3c 0.01) and AVTD (r = 0.48, p \u3c 0.05). Also, bulls that secreted more E2 after a GnRH treatment at 15 wk had larger AVTD (r = 0.62, p \u3c 0.62, p \u3c 0.01) and TW2 (r = 0.45, p \u3c 0.10). Thus, differences between slow and fast growing bulls are affected by the ability of the testis to secrete testosterone early in life. Also, the existence of correlations between FSH, steroids and characteristics of the testis at AGEl and prepuberty points toward a role played by these hormones at distinct phases of germ cell development. Study 4. A study was conducted to identify the cell types that express retinol-binding protein (RBP) in the bovine testis and to evaluate the profiles of RBP mRNA levels as related to testicular development. Furthermore, the hypothesis that RBP could serve as a marker of state of development of the seminiferous epithelium was evaluated. At the ages of 10 (n=3), 20 (n=8) and 34 (n=7) weeks, Angus bulls were bled three times and surgically castrated afterwards. Blood samples were assayed for LH and testosterone (T) and the degree of seminiferous tubule development was evaluated in tissue samples stained with hematoxylin and eosin. Immunolocalization of RBP was detected according to the biotin-strepavidinhorseadish peroxidase method (samples from 10-wk old testes could not be analyzed). Nylon membranes containing isolated total RNA were hybridized with a bovine cDNA (bcRBP-700) and a β-actin probe and slot blots were carried out to determine the abundance of RBP and β-actin transcripts. Age-related changes in testis weight, hormone concentrations and relative quantity of RBP transcripts were determine by analysis of variance. Results showed that testis weight and levels of LH and T increased with age (p \u3c 0.05). Also, seminiferous tubules at 10 wk had immature Sertoli cells and gonocytes but, at 20 wk, spermatogonia and few spermatocytes were detected. At 34 wk, Sertoli cells appeared differentiated and spermatids were observed. As never shown before in the bovine species, RBP was detected in Sertoli, Leydig and peritubular cells at the ages of 20 and 34 wk, but no immunoreactivity was present in the germ cells. Furthermore, no difference in staining between Sertoli cells from tubules with or without germ cells was detected. Thus, as determined by immunohistochemistry, RBP does not appear to be a distinct marker of Leydig and Sertoli cell differentiation. Northern hybridization of testicular RNA revealed the presence of a mlUSfA of 1.1 Kb, which was similar to previous RBP transcripts found in bovine conceptuses and extraembryonic membranes. Densitometric scanning of slot blots indicated that the fraction of total RNA coding for RBP was 50 % higher at 10 wk than at 20 and 34 wk. Thus, it is possible that testicular RBP mRNA is down-regulated by testosterone and/or LH, but further studies are needed to verify this hypothesis

Evaluation of thermal comfort in surgical environments using Fanger's method and equivalent temperatures

Em ambientes cirúrgicos as condições de conforto térmico precisam ser as melhores possíveis para que o cirurgião e a equipe médica trabalhem em ambientes cirúrgicos as condições de conforto térmico precisam ser as melhores possíveis para que o cirurgião e a equipe médica trabalhem em condições favoráveis para o sucesso do procedimento cirúrgico. Neste trabalho são avaliadas condições de conforto térmico em salas cirúrgicas utilizando o método de Fanger e temperaturas equivalentes. Foram realizadas medições de variáveis ambientais e avaliações subjetivas baseadas em questionários. A aplicação do método de Fanger mostrou-se adequada na avaliação de condições de conforto térmico em salas cirúrgicas, embora seja necessário cuidado especial em sua utilização e na análise dos resultados. Paralelamente, resultados de estudo comparativo com trabalhos de outros autores mostraram valores praticamente iguais de temperaturas equivalentes de conforto térmico, em torno de 22 oC, para todos os membros da equipe cirúrgica. Esse resultado é particularmente útil para avaliar diferentes condições ambientais e pessoais em propiciar condições adequadas de conforto térmico aos diferentes membros da equipe cirúrgica.In surgical environments thermal comfort conditions need to be the best possible to allow surgeons and the medical team to work in favourable conditions for the success of procedures. In this study, thermal comfort conditions in surgery rooms were analyzed using Fanger's method and equivalent temperatures. Measurements of environmental variables and subjective evaluations based on questionnaires were undertaken. The application of Fanger's method was proven to be appropriate for the evaluation of thermal comfort conditions in surgical rooms, although special care is necessary on its use and in the analysis of the results. Moreover, results of a comparative study with other authors' works showed practically the same values of thermal comfort equivalent temperatures, which were around 22 oC for all members of the surgical team. That result is particularly useful to evaluate different environmental and personal conditions in order to provide suitable thermal comfort conditions for different members of the surgical team

Avaliação de conforto térmico em ambientes cirúrgicos utilizando método de Fanger e temperaturas equivalentes

Em ambientes cirúrgicos as condições de conforto térmico precisam ser as melhores possíveis para que o cirurgião e a equipe médica trabalhem em condições favoráveis para o sucesso do procedimento cirúrgico. Neste trabalho são avaliadas condições de conforto térmico em salas cirúrgicas utilizando o método de Fanger e temperaturas equivalentes. Foram realizadas medições de variáveis ambientais e avaliações subjetivas baseadas em questionários. A aplicação do método de Fanger mostrou-se adequada na avaliação de condições de conforto térmico em salas cirúrgicas, embora seja necessário cuidado especial em sua utilização e na análise dos resultados. Paralelamente, resultados de estudo comparativo com trabalhos de outros autores mostraram valores praticamente iguais de temperaturas equivalentes de conforto térmico, em torno de 22 oC, para todos os membros da equipe cirúrgica. Esse resultado é particularmente útil para avaliar diferentes condições ambientais e pessoais em propiciar condições adequadas de conforto térmico aos diferentes membros da equipe cirúrgica

Analisys of local thermal discomfort in surgical environments with the use of mannequins, measurement of environmental variables and subjective evaluation

Na avaliação de conforto térmico em ambientes interiores não basta analisar as condições de conforto para o corpo como um todo, pois há a necessidade de se analisar também as condições de desconforto térmico local. Em ambientes complexos, tais como os ambientes cirúrgicos, onde os membros da equipe cirúrgica ocupam diferentes posições no ambiente e desempenham atividades distintas, a análise de condições de desconforto térmico local torna-se ainda mais premente. No presente trabalho foram analisadas condições de desconforto térmico local devido a assimetrias da temperatura radiante, diferença vertical de temperatura do ar e risco de correntes de ar utilizando manequim, medição de variáveis ambientais e avaliação subjetiva. Resultados da avaliação subjetiva mostraram níveis de insatisfação de até 35 % dos anestesistas e enfermeiros com correntes de ar e de até 85% dos cirurgiões com o calor do foco cirúrgico. Resultados similares foram obtidos a partir da medição de variáveis ambientais e com o uso de manequim. Estes resultados ressaltam ainda mais a grande dificuldade de se prover condições de conforto térmico neste tipo de ambiente. Entretanto, a utilização de diferentes ferramentas de análise pode auxiliar na busca de se prover condições de conforto térmico as melhores possíveis para todos os membros da equipe cirúrgica

Hypochlorous Acid-Induced Heme Degradation from Lactoperoxidase as a Novel Mechanism of Free Iron Release and Tissue Injury in Inflammatory Diseases

Lactoperoxidase (LPO) is the major consumer of hydrogen peroxide (H2O2) in the airways through its ability to oxidize thiocyanate (SCN−) to produce hypothiocyanous acid, an antimicrobial agent. In nasal inflammatory diseases, such as cystic fibrosis, both LPO and myeloperoxidase (MPO), another mammalian peroxidase secreted by neutrophils, are known to co-localize. The aim of this study was to assess the interaction of LPO and hypochlorous acid (HOCl), the final product of MPO. Our rapid kinetic measurements revealed that HOCl binds rapidly and reversibly to LPO-Fe(III) to form the LPO-Fe(III)-OCl complex, which in turn decayed irreversibly to LPO Compound II through the formation of Compound I. The decay rate constant of Compound II decreased with increasing HOCl concentration with an inflection point at 100 µM HOCl, after which the decay rate increased. This point of inflection is the critical concentration of HOCl beyond which HOCl switches its role, from mediating destabilization of LPO Compound II to LPO heme destruction. Lactoperoxidase heme destruction was associated with protein aggregation, free iron release, and formation of a number of fluorescent heme degradation products. Similar results were obtained when LPO-Fe(II)-O2, Compound III, was exposed to HOCl. Heme destruction can be partially or completely prevented in the presence of SCN−. On the basis of the present results we concluded that a complex bi-directional relationship exists between LPO activity and HOCl levels at sites of inflammation; LPO serve as a catalytic sink for HOCl, while HOCl serves to modulate LPO catalytic activity, bioavailability, and function

Percepções do preceptor sobre o processo ensino-aprendizagem e práticas colaborativas na atenção primária à saúde

Objetivo: Analisar as percepções dos preceptores acerca do processo ensino-aprendizagem, bem como as fortalezas e as fragilidades para implementar as práticas colaborativas na Atenção Primária à Saúde.Método: Pesquisa qualitativa, desenvolvida entre outubro e dezembro de 2019 com 96 preceptores (cirurgiões-dentistas, enfermeiros e médicos) da Estratégia de Saúde da Família. Os dados foram obtidos através de questionário e submetidos a Análise de Conteúdo, utilizando o software Maxqda-2020.Resultados: Foram evidenciadas três categorias: 1. Um novo saber-fazer precisa ser ensinado a quem ensina, 2. o ensinar e o assistir no processo da preceptoria e 3. abordagem centrada na pessoa: paradigma para o trabalho colaborativo revelam dificuldades e tensões no trabalho do preceptor e de práticas colaborativas.Conclusão: O estudo identificou a necessidade de qualificar os preceptores com novas abordagens para o desenvolvimento do processo ensino-aprendizagem, para o trabalho em equipe e práticas interprofissionais colaborativas no contexto da Atenção Primária à Saúde. Palavras-chave: Atenção primária à saúde. Preceptoria. Ensino. Aprendizagem. Relações interprofissionais

Feeding effects of cottonseed and its co-products on the meat proteome from ram lambs

Gossypol easily pairs with lysine side chains and enzymes involved in the cellular growth process. The effect of gossypol (a compound present in cotton co-products) in ruminant metabolism and meat quality is not yet clear. This study was undertaken in order to evaluate the effects of cotton co-products in lamb muscle proteome. Twenty-four Santa Inês ram lambs, 5-months old (20.6 ± 1.9 kg), were randomly assigned to four treatments: control (without cottonseed), whole cottonseed, cottonseed meal and high oil cottonseed meal. At 95 days into the experiment, lambs were slaughtered and samples from Longissimus dorsi were collected. Proteins were extracted and analyzed by 2-D electrophoresis. Spots showing a significant effect from the treatment (the “treatment effect”) and present in more than 90 % of the samples were identified using mass spectrometry. Cotton co-products decreased the abundance of aldehyde and malate dehydrogenases, creatine kinase M-type and Adenosine triphosphate (ATP) synthase. They also increased four proteins related to muscle contraction. Thus, feeding cotton co-products to lambs changed the abundance of important muscle proteins. A cotton co-product diet induced a negative impact on the energy supply of muscle cells and, consequently, the abundance of ATP dependent proteins (contractile apparatus) increased, probably in order to offset and maintain muscle function. These proteomic changes can promote our understanding of alterations in the sensorial properties of meat due to cotton co-product diets in further investigations

TRABALHO COLABORATIVO NO USO DE SOFTWARE DE GEOMETRIA DINÂMICA

The school, as the teacher, does not live isolated, but inserted in a context that should be used in favor of its development, and the professional development of its teachers. Thus, this study sought to examine the importance of interactions between teachers, promoting a collaborative professional culture sharing doubts and uncertainties to achieve a common goal, promote effective learning of geometry through technologies. For this study a mining project that had the partnership between school and university the important structure for debate and discussion on the use of new technologies for math teaching aid / geometry. This text reflects a qualitative research, which a weekly monitoring in the empirical field represented by the school's computer lab, where took place the majority of the proposed activities.La escuela y el maestro no vive aislado, sino que se inserta en un contexto que se debe utilizar en favor de su desarrollo, y el desarrollo profesional de sus profesores. Por lo tanto, este estudio trató de examinar la importancia de las interacciones entre los maestros, la promoción de un profesional de colaboración de intercambio de la cultura dudas e incertidumbres para lograr un objetivo común, promover el aprendizaje efectivo de la geometría a través de las tecnologías. Para este estudio un proyecto minero que tuvo la colaboración entre la escuela y la universidad de la estructura importante para el debate y la discusión sobre el uso de las nuevas tecnologías para la enseñanza de matemáticas ayuda / geometría. Este texto refleja una investigación cualitativa, que se utilizó dun seguimiento semanal en el campo empírico representada por el laboratorio de computación de la escuela, donde tuvo lugar la mayor parte de las actividades propuestas.A escola, assim como todos que a compõem, não vive isolada, mas inserida num contexto que deve ser usado a favor de seu desenvolvimento, e para o desenvolvimento profissional de seus docentes. Nesse sentido, este trabalho buscou examinar a importância das interações entre professores, promovendo uma cultura profissional colaborativa que partilhe dúvidas e incertezas, para alcançar um objetivo em comum, e promover um aprendizado eficaz da geometria, por meio da interação com as tecnologias, tão presentes fora dos muros da escola. Assim, analisamos um projeto mineiro que apresentou, na parceria entre escola e universidade, a estrutura de debate e discussão sobre o uso das novas tecnologias para o auxílio de ensino de matemática/geometria. Este texto apresenta uma pesquisa qualitativa, com acompanhamento semanal no campo empírico representado pelo laboratório de informática da escola, onde aconteceram a maioria das atividades propostas

FORMAÇÃO DE PROFESSORES NO BRASIL: HISTÓRIA, PERSPECTIVAS E DILEMAS

This article deals with the theme of teacher education, covering historical aspects, perspectives and dilemmas. As the main objective to be achieved, it will be presented a historical clipping and the trajectory of teacher training in Brazil in schools where the Constitution of Basic Education is applied in a democratic and reflective way. Hence the importance of reflecting on the development provided by teachers, identifying the ways in which students themselves become agents of the learning process, changes in critical thinking, modifications and decisions about the ideal learning environment with the school group. To this end, a qualitative and descriptive bibliographic research was carried out. The importance of having school supervisors acting as mediators of emotional events within the school is summarized to ensure the quality of the formal educational process in Brazil.  Este artigo trata do tema da formação de professores, abrangendo aspectos históricos, perspectivas e dilemas. Como principal objetivo a ser alcançado, apresentar-se-á um recorte histórico e a trajetória da formação de professores no Brasil nas escolas onde a Constituição da Educação Básica é aplicada de forma democrática e reflexiva. Daí a importância de refletir sobre o desenvolvimento proporcionado pelos professores, identificando as formas como os próprios alunos se tornam agentes do processo de aprendizagem, mudanças de pensamento crítico, modificações e decisões sobre o ambiente ideal de aprendizagem com o grupo escolar. Para tanto, realizou-se pesquisa bibliográfica qualitativa e descritiva. A importância de ter supervisores escolares atuando como mediadores dos acontecimentos emocionais dentro da escola se resume para garantir a qualidade do processo educacional formal no Brasil.  Este artigo trata do tema da formação de professores, abrangendo aspectos históricos, perspectivas e dilemas. Como principal objetivo a ser alcançado, apresentar-se-á um recorte histórico e a trajetória da formação de professores no Brasil nas escolas onde a Constituição da Educação Básica é aplicada de forma democrática e reflexiva. Daí a importância de refletir sobre o desenvolvimento proporcionado pelos professores, identificando as formas como os próprios alunos se tornam agentes do processo de aprendizagem, mudanças de pensamento crítico, modificações e decisões sobre o ambiente ideal de aprendizagem com o grupo escolar. Para tanto, realizou-se pesquisa bibliográfica qualitativa e descritiva. A importância de ter supervisores escolares atuando como mediadores dos acontecimentos emocionais dentro da escola se resume para garantir a qualidade do processo educacional formal no Brasil.  Este artigo trata do tema da formação de professores, abrangendo aspectos históricos, perspectivas e dilemas. Como principal objetivo a ser alcançado, apresentar-se-á um recorte histórico e a trajetória da formação de professores no Brasil nas escolas onde a Constituição da Educação Básica é aplicada de forma democrática e reflexiva. Daí a importância de refletir sobre o desenvolvimento proporcionado pelos professores, identificando as formas como os próprios alunos se tornam agentes do processo de aprendizagem, mudanças de pensamento crítico, modificações e decisões sobre o ambiente ideal de aprendizagem com o grupo escolar. Para tanto, realizou-se pesquisa bibliográfica qualitativa e descritiva. A importância de ter supervisores escolares atuando como mediadores dos acontecimentos emocionais dentro da escola se resume para garantir a qualidade do processo educacional formal no Brasil.