974 resultados para Sexual maturation
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Obesity has a complex, multi-factorial etiology. Infectious agents have recently emerged as a possible contributor to the current obesity epidemic. Seven viruses have demonstrated an association with obesity in animals; however, Adenovirus-36 (Ad-36) is the only known virus associated with obesity in humans. The primary aim of this research was to determine the association between Ad-36 infection and the expression of obesity related hormones in children. Additionally, this study proposed to compare the mean three year change in the level of obesity related hormones between Ad-36 positive and negative children. This study utilized pilot data collected from 98 children at baseline and year three of the Project Heartbeat! cohort. Fasting serum samples were analyzed for the concentration of adiponectin, insulin and leptin. The crude analysis uncovered Ad-36 positive children had significantly lower mean concentrations of insulin (p=0.039) and leptin (p=0.038) at baseline compared to Ad-36 negative children. The results of the adjusted analysis indicated the leptin association with Ad-36 infection at baseline was statistically significant even after controlling for age, sex, ethnicity, and BMI percentile. The longitudinal evaluation revealed individuals with a history of Ad-36 infection experienced a larger mean decrease in adiponectin, a larger mean increase in leptin, and a smaller mean increase in insulin levels over a three year period compared to individuals without a history of infection. These results suggest Ad-36 infection may produce changes in hormone expression. The only statistically significant findings in the crude and adjusted longitudinal analysis occurred at baseline when the children were younger, suggesting physical changes that occur during sexual maturation may mask or enhance Ad-36 induced changes in hormone expression. Furthermore, the longitudinal analysis revealed the duration and course of Ad-36 infection may influence changes in the expression of obesity-related hormones. Taken together, the results of this pilot study are suggestive of an association between Ad-36 infection and the expression of obesity-related hormones.^
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Among fruit-fly species of the genus Drosophila there is remarkable variation in sperm length, with some species producing gigantic sperm (e.g., > 10 times total male body length). These flies are also unusual in that males of some species exhibit a prolonged adult nonreproductive phase. We document sperm length, body size, and sex-specific ages of reproductive maturity for 42 species of Drosophila and, after controlling for phylogeny, test hypotheses to explain the variation in rates of sexual maturation. Results suggest that delayed male maturity is a cost of producing long sperm. A possible physiological mechanism to explain the observed relationship is discussed.
Parent Loss in Adolescence and its Impact on Sense of Self: When an Adolescent Boy Loses His Mother.
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Adolescence is a developmental phase that involves physical, emotional, and cognitive changes. Often this period is one of transition that requires significant adjustment both with the individual and the family. It is considered to start with puberty, sometime between the ages of 10 and 13, and end with the transition into adulthood (Kruse & Walper, 2008). Puberty is a term that is used to describe the physical changes that generally occur during adolescence. It is an aspect of the changes that occur during the overarching phase of development. Within adolescence, individuals are confronted with many developmental tasks such as establishing an individual identity, making decisions about the future, and moving from dependence on families to independence (Austrian, 2008).There are many changes that occur during adolescence, including sexual maturation and functioning, endocrine developments, and skeletal and muscular changes. Boys will see a growth of body, pubic, and facial hair, their voice will deepen, and they will begin having erections and wet dreams (Kruse & Walper, 2008). The accelerated transformation of this phase generally has an emotional impact and individuals may feel concerned or self-conscious about their appearance. Ausubel, Montemayor, and Svajian (1977) suggest that adolescents may be more sensitive during this period of development. This sensitivity may be in part due to the rapid growth resulting in a sense of awkwardness in appearance and physical coordination.
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Carotenoids, particularly astaxanthin, are the primary pigment in crustacean shell colour. Sub-adults of the western rock lobster, Panulirus cygnus, moult from a deep red colour (termed the red phase) to a much paler colour (the white phase) at sexual maturation. We observe a 2.4-fold difference in the amount of total carotenoid present in the shell extracts of reds compared to whites, as might be expected. However, analysis of the underlying epithelium shows that there is no correlation with shell colour and the amount of free (unesterified) astaxanthin-the level of free astaxanthin in reds and whites is not significantly different. Instead, we observe a correlated two-fold difference in the amount of esterified astaxanthin present in the epithelium of red versus white individuals. These data suggest a role for esterified astaxanthin in regulating shell colour formation and suggest that esterification may promote secretion and eventual incorporation of unesterified astaxanthin into the exoskeleton. (c) 2005 Elsevier Inc. All rights reserved.
Resumo:
At present, little is known about signal transduction mechanisms in schistosomes, which cause the disease of schistosomiasis. The mitogen-activated protein kinase (MAPK) signaling pathways, which are evolutionarily conserved from yeast to Homo sapiens, play key roles in multiple cellular processes. Here, we reconstructed the hypothetical MAPK signaling pathways in Schistosoma japonicum and compared the schistosome pathways with those of model eukaryote species. We identified 60 homologous components in the S. japoncium MAPK signaling pathways. Among these, 27 were predicted to be full-length sequences. Phylogenetic analysis of these proteins confirmed the evolutionary conservation of the MAPK signaling pathways. Remarkably, we identified S. japonicum homologues of GTP-binding protein beta and alpha-I subunits in the yeast mating pathway, which might be involved in the regulation of different life stages and female sexual maturation processes as well in schistosomes. In addition, several pathway member genes, including ERK, JNK, Sja-DSP, MRAS and RAS, were determined through quantitative PCR analysis to be expressed in a stage-specific manner, with ERK, JNK and their inhibitor Sja-DSP markedly upregulated in adult female schistosomes. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
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Executive functions are determinant cognitive processes for student success, since they execute and control complex cognitive activities such as reasoning, planning and solving problems. The development of the executive functions performances begin early at childhood going through the adolescence until adulthood, concomitant with the neuroanatomical, functional and blood perfusion changes over the brain. In this scenario, exercise has been considered an important environmental factor for neurodevelopment, as well as for the promotion of cognitive and brain health. However, there are no large scientific studies investigating the effects of a single vigorous aerobic exercise session on executive functions in adolescents. Objective: To verify the acute effect of vigorous aerobic exercise on executive functions in adolescents. Methods: A randomized controlled trial (RCT) with crossover design was used. 20 pubescent from both sexes/gender with age between 10 and 16 years were submitted to two sessions of 30min each: 1) The aerobic exercise session intensity was between 65 and 75% of heart rate reserve, in which 5min for warm-up, 20min at the target intensity and 5min of cool down; and 2) control session watching cartoons. The computerized Stroop test – Testinpacs and trail making test were used to evaluate the inhibitory control and cognitive flexibility assessment respectively, before and after both experimental and control sessions. The reaction time (RT) and number of errors (n) of Stroop test were recorded. The total time (TT) and the number of errors (n) of the trail making test were also recorded. Results: The control session’s RT did not present significant differences in the Stroop test. On the other hand, the exercise session’s RT decreased significantly (p<0.01) after the session. The number of errors made at the Stroop test had no significant differences in control and exercise sessions. The ΔTT of trail making test of exercise session was significantly (p<0.001) lower than the control session’s. Errors made in trail making test did not show significant differences between control and exercise sessions. Additionally, there was significant and positive association among the Stroop test ΔRT of exercise session with xiii chronological age (r= 0.635, p=0.001; r 2 = 0.404, p=0.003) and sexual maturation (rs= 0.580, p=0.007; r 2 = 0.408, p=0.002). Differently, there was no association among the control session ΔRT and chronological age (r= – 0.144, p=0.273; r 2 = 0.021, p=0.545) or sexual maturation (rs= –0.155, p=0.513; r 2 = 0.015, p=0.610). Conclusion: Vigorous aerobic exercise seems to improve acutely executive functions in adolescents. The effect of exercise on inhibitory control performance was associated to pubertal stage and chronological age. In other words, the benefits of exercise were more evident in early adolescence (↑ ΔRT) and its magnitude decreases along the growing up process.
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To further investigate the importance of insulin signaling in the growth, development, sexual maturation and egg production of adult schistosomes, we have focused attention on the insulin receptors (SjIRs) of Schistosoma japonicum, which we have previously cloned and partially characterised. We now show, by Biolayer Interferometry, that human insulin can bind the L1 subdomain (insulin binding domain) of recombinant (r)SjIR1 and rSjIR2 (designated SjLD1 and SjLD2) produced using the Drosophila S2 protein expression system. We have then used RNA interference (RNAi) to knock down the expression of the SjIRs in adult S. japonicum in vitro and show that, in addition to their reduced transcription, the transcript levels of other important downstream genes within the insulin pathway, associated with glucose metabolism and schistosome fecundity, were also impacted substantially. Further, a significant decrease in glucose uptake was observed in the SjIR-knockdown worms compared with luciferase controls. In vaccine/challenge experiments, we found that rSjLD1 and rSjLD2 depressed female growth, intestinal granuloma density and faecal egg production in S. japonicum in mice presented with a low dose challenge infection. These data re-emphasize the potential of the SjIRs as veterinary transmission blocking vaccine candidates against zoonotic schistosomiasis japonica in China and the Philippines.
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Shell growth of the whelk Nassarius (¼Hinia) reticulatus was studied in the Ria de Aveiro (north-west Portugal) between 1995 and 1998. Temporal analysis of shell height frequency distributions demonstrated that growth occurs during the ¢rst ¢ve years of life, whelks attaining a size of 6.7^7.8 mm in the 1st year, 12.1^14.5 mm in the 2nd year, 18^19.5 mm in the 3rd year, 22.7^23.6 mm in the 4th year and by the 5th year males have achieved an average size of 25 mm whilst females have reached 27 mm. Age estimates from internal microscopic annual growth lines present in the shell lip suggest that large whelks may achieve a longevity of at least 11 years. External annual rings become less discernible as the whelks increase in size and estimates of their age based solely on ring counts can underestimate their age. In males sexual maturation is reached between the 3rd and 4th years whilst in females it is attained between the 4th and 5th years. Imposex was visible in 2 year old females and attained maximum development by the 5th year.
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The Caatinga biome is rich in endemic fish species fauna. The present study the results of fish faunal surveys conducted in the hydrographic basin of Piranhas-Assu of the Brazilian Caatinga biome. The fish samples collected were distributed in four orders (Characiformes, Perciformes, Siluriformes and Synbranchiformes), 11 families (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae) and 22 species, of which 17 are endemic and five have been introduced from other basins. The order Characiformes was the most representative in number of species (46,35% ) followed by Perciformes (35,38%), Siluriformes (17,44%) and Synbranchiformes (0,5%). The Nile tilapia, Oreochomis niloticus, the only exotic species, was most expressive in number of individuals (24.92%) followed by the native species piau preto, Leporinus piau (18,77 %). Considering the relative frequency of occurrence of the 22 species, 13 were constant, five were accessory and four were occasional. This study investigated the reproductive ecology of an endemic fish black piau, Leporinus piau from the Marechal Dutra reservoir, Acari, Rio Grande do Norte. Samplings were done on a monthly basis from January to December 2009, and a total of 211 specimens were captured. The environmental parameters such as rainfall, temperature, pH, electrical conductivity and dissolved oxygen of water were recorded. The sampled population showed a slight predominance of males (55%), however females were larger and heavier. Both sexes of L. piau showed positive allometric growth, indicating a higher increase of weight than length. The first sexual maturation of males occurred at smaller size, with 16.5 cm in total length than females (20.5 cm). During the reproductive period, the condition factor and gonadosomatic index (GSI) of L. piau were negatively correlated. This species has large oocytes with a high mean fecundity of 54.966 with synchronous oocyte development and total spawning
Resumo:
The Caatinga biome is rich in endemic fish species fauna. The present study the results of fish faunal surveys conducted in the hydrographic basin of Piranhas-Assu of the Brazilian Caatinga biome. The fish samples collected were distributed in four orders (Characiformes, Perciformes, Siluriformes and Synbranchiformes), 11 families (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae) and 22 species, of which 17 are endemic and five have been introduced from other basins. The order Characiformes was the most representative in number of species (46,35% ) followed by Perciformes (35,38%), Siluriformes (17,44%) and Synbranchiformes (0,5%). The Nile tilapia, Oreochomis niloticus, the only exotic species, was most expressive in number of individuals (24.92%) followed by the native species piau preto, Leporinus piau (18,77 %). Considering the relative frequency of occurrence of the 22 species, 13 were constant, five were accessory and four were occasional. This study investigated the reproductive ecology of an endemic fish black piau, Leporinus piau from the Marechal Dutra reservoir, Acari, Rio Grande do Norte. Samplings were done on a monthly basis from January to December 2009, and a total of 211 specimens were captured. The environmental parameters such as rainfall, temperature, pH, electrical conductivity and dissolved oxygen of water were recorded. The sampled population showed a slight predominance of males (55%), however females were larger and heavier. Both sexes of L. piau showed positive allometric growth, indicating a higher increase of weight than length. The first sexual maturation of males occurred at smaller size, with 16.5 cm in total length than females (20.5 cm). During the reproductive period, the condition factor and gonadosomatic index (GSI) of L. piau were negatively correlated. This species has large oocytes with a high mean fecundity of 54.966 with synchronous oocyte development and total spawning
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Objetivo: Describir la relación de las etapas de cambio conductual frente al consumo de frutas y verduras con el estado nutricional en un grupo de escolares de Bogotá, Colombia, pertenecientes al estudio FUPRECOL. Métodos: Estudio de corte transversal en 1.922 niños y adolescentes entre 9 y 17 años, pertenecientes a nueve instituciones educativas oficiales de Bogotá. Se aplicó de manera auto-diligenciada el cuestionario de cambio de comportamiento (CCC-Fuprecol) validado en el “estudio FUPRECOL” y se calculó el Índice de Masa Corporal (IMC) como marcador del estado nutricional. Se calcularon prevalencias y se establecieron asociaciones mediante modelos de regresión logística binaria. Resultados: La muestra estuvo conformada por 1.045 niños-niñas y adolescentes vs hombres (45.6%) y mujeres (54.3%) y 877. La mayor proporción de consumo de frutas en el subgrupo de hombres (niños entre 9 y 12 años vs. adolescentes entre 13 y 17 años) se observó en la etapa de mantenimiento, (53.3 % vs. 38.8 %, X2 p<0.001), seguido de preparación/acción (25.0 % vs. 32.4 %, X2 p<0.001). En mujeres entre 9 y 12 años, la mayor proporción se ubicó en la etapa de mantenimiento (54.4 %), a diferencia de las adolescentes entre 13 y 17 años que acusaron mayor frecuencia la etapa de preparación/acción (42.0 %). Se observó que pertenecer al grupo de mujeres, se asociaba como variable para el cumplimiento de la recomendación mínima de frutas y verduras con valores de OR 1.54 (IC95% 1.22-1.93) y OR 1.48 (IC95% 1.19-1.84), respectivamente. Conclusiones: Aproximadamente, 66 % de los participantes tienen la intención o la voluntad de cumplir las recomendaciones de consumo de frutas y verduras. La identificación temprana de niños y adolescentes con bajo consumo de alimentos vegetales, permitirá implementar intervenciones para promover comportamientos saludables a fin de prevenir el riesgo cardiometabólico en la edad adulta.
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In contrast to the definition of metabolic syndrome (MetS) in adults, there is no standard definition of MetS in pediatric populations. We aimed to assess the differences in the prevalence of MetS in children and adolescents aged 9–17 years in the city of Bogota (Colombia) using four different operational definitions for these age groups and to examine the associated variables. A total of 673 children and 1,247 adolescents attending public schools in Bogota (54.4% girls; age range 9–17.9 years) were included. The prevalence of MetS was determined by the definitions provided by the International Diabetes Federation (IDF) and three published studies by Cook et al., de Ferranti et al., and Ford et al. The prevalence of MetS was 0.3%, 6.3%, 7.8%, and 11.0% according to the IDF, Cook et al., Ford et al., and de Ferranti et al. definitions, respectively. The most prevalent components were low high-density lipoprotein cholesterol and high triglyceride levels, whereas the least prevalent components were abdominal obesity and hyperglycemia. Overall, the prevalence of MetS was higher in obese than in non-obese schoolchildren. In conclusion, MetS diagnoses in schoolchildren strongly depend on the definition chosen. These findings may be relevant to health promotion efforts for Colombian youth to develop prospective studies and to define which cut-offs are the best indicators of future morbidity.
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Objetivo: Este estudio describe los percentiles de la prueba de carrera de ida y vuelta 4 x 10 m en escolares de 9 a 17 años, de Bogotá, Colombia, pertenecientes al estudio Asociación de la fuerza prensil con manifestaciones tempranas de riesgo cardiovascular en niños colombianos. “FUPRECOL” Métodos: Estudio descriptivo transversal, en 2502 varones (42.7%) y 3349 mujeres (57,2%), de edades entre 9 y 17 años, pertenecientes a 24 instituciones educativas del sector oficial, en Bogotá, Colombia. La velocidad/agilidad se evaluó con la prueba de carrera de ida y vuelta 4 x 10 m (componente motor de la batería Fuprecol). Se calcularon los percentiles (P3, P10, P25, P50, P75, P90 y P97) y curvas centiles por el método LMS, según el sexo y la edad; y se realizó una comparación entre los valores de la velocidad-agilidad observados con estudios internacionales. Resultados: La edad promedio de los participantes fue 12,7 (DE 2,4) años. Al comparar por sexos, los varones presentan un mejor rendimiento en la prueba de carrera 4 x 10 m que las mujeres. En varones, el P50 osciló entre 11,9 segundos y 13,1 segundos, mientras que en mujeres el P50 osciló entre 14,3 segundos y 15,0 segundos. Al comparar los resultados de este estudio por grupos de edades y sexos, con trabajos internacionales, el P50 fue mayor al reportado en los trabajos de España, Portugal y el estudio HELENA realizado en 9 países europeos. Esta misma tendencia fue observada al comparar la media y la desviación estándar con escolares de Argentina, Francia y el mismo estudio HELENA. Conclusiones: Se registran percentiles de la prueba de carrera de ida y vuelta 4 x 10 m en función de las edades y el sexo. Estos valores pueden ser utilizados tanto para evaluar los niveles de aptitud de los estudiantes como para detectar a estudiantes cuyos niveles de condición física están por debajo de un mínimo saludable.
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The International FItness Scale (IFIS) is a self-reported measure of physical fitness that could easily. This scale has been validated in children, adolescents, and young adults; however, it is unknown whether the IFIS represents a valid and reliable estimate of physical fitness in Latino-American youth population. In the present study we aimed to examine the validity and reliability of the IFIS on a population-based sample of schoolchildren in Bogota, Colombia. Participants were 1,875 Colombian youth (56.2% girls) aged 9 to 17.9 years old. We measured adiposity markers (body fat, waist-to-height ratio, skinfold thicknesses and BMI), blood pressure, lipids profile, fasting glucose, and physical fitness level (self reported and measured). Also, a validated cardiometabolic risk index was used. An age- and sex-matched sample of 229 Schoolchildren originally not included in the study sample fulfilled IFIS twice for reliability purposes. Our data suggest that both measured and self-reported overall fitness were associated inversely with adiposity indicators and a cardiometabolic risk score. Overall, schoolchildren who self-reported “good” and “very good” fitness had better measured fitness than those who reported “very poor” and “poor” fitness (all p<0.001). Test–retest reliability of IFIS items was also good, with an average weighted Kappa of 0.811. Therefore, our findings suggest that self-reported fitness, as assessed by IFIS, is a valid, reliable, and health-related measure, and it can be a good alternative for future use in large studies with Latin-schoolchildren from Colombia.
Resumo:
Introducción y objetivo: La escala de auto-reporte de la condición física (IFIS) “The International FItness Scale”, fue creada como parte del proyecto financiado por la unión europea HELENA Study “Healthy Lifestyle in Europe by Nutrition in Adolescence”. A la fecha, no se conoce ningún estudio que haya examinado el auto-reporte de la condición física en un contexto distinto al Europeo. Este trabajo evalúa por auto-reporte la condición física relacionada con la salud (CFRS) en una muestra de niños y adolescentes del distrito de Bogotá pertenecientes al grupo FUPRECOL. Materiales y Método: Estudio transversal en 1.922 escolares (54.3% mujeres). Se aplicó de manera auto-administrada la escala “IFIS”. Se midió el peso, talla, circunferencia de cintura y se calculó el índice de masa corporal (IMC) en kg/m2. La capacidad aeróbica, el índice general de fuerza (z-score fuerza prensil + z-score salto de longitud), la velocidad/agilidad y la flexibilidad fueron como indicadores objetivos de la CFRS objetiva y directa. Resultados: La muestra estuvo conformada por 1.922 escolares, de los cuales 1.045 fueron mujeres (54.3%) y 877 hombres (45.6%). El análisis ANOVA mostró que los varones tenían mayores valores de peso (p<0.003), estatura (p<0.001), CC (p<0.001), capacidad aeróbica (p<0.001), velocidad/agilidad (p<0.001) e índice general de fuerza (p<0.001), mientras que las mujeres presentaron exceso de peso por IMC (sobrepeso y obesidad). En el componente de condición física general, las puntuaciones más altas en la escala “IFIS” se encontraron en la categoría buena (40%), seguido de aceptable (34%), mientras que la puntuación más baja se encontró en la categoría muy mala/mala (6%). En población general, relaciones lineales fueron observadas entre el auto-reporte de la CFRS por la escala “IFIS” y la mayoría de los indicadores del fitness evaluado objetivamente. El análisis post-hoc ajustado por sexo, edad y etapa de maduración reveló que los escolares que acusaron mejores valores en la auto-percepción de los dominios del “IFIS”, presentaron mejor desempeño en los indicadores de CFRS objetivos. Conclusión: Este trabajo describe por primera vez en población Latina, que el auto-reporte con la escala “IFIS”, es un instrumento válido para evaluar la CFRS, y además posee una adecuada capacidad para clasificar la aptitud física en población escolar de Bogotá, Colombia. Esta escala se encuentra disponible para otros investigadores interesados en evaluar la condición física muscular en América Latina.