RESUMO
The aim of the present study was to determine the effects of three weeks of hyperbaric oxygen (HBO2) training on oxidative stress markers and endurance performance in young soccer players. Participants (18.6 ± 1.6 years) were randomized into hyperbaric-hyperoxic (HH) training (n = 6) and normobaric normoxic (NN) training (n = 6) groups. Immediately before and after the 5th, 10th, and 15th training sessions, plasma oxidative stress markers (lipid hydroperoxides and uric acid), plasma antioxidant capacity (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid [TROLOX]), arterial blood gases, acid-base balance, bases excess (BE), and blood lactate analyses were performed. Before and after intervention, maximal oxygen uptake (VO2max) and peak power output (PPO) were determined. Neither HH nor NN experienced significant changes on oxidative stress markers or antioxidant capacity during intervention. VO2max and PPO were improved (moderate effect size) after HH training. The results suggest that HBO2 endurance training does not increase oxidative stress markers and improves endurance performance in young soccer players. Our findings warrant future investigation to corroborate that HBO2 endurance training could be a potential training approach for highly competitive young soccer players.
RESUMO
Adducts of a number of tertiary pnicogen ligands ER(3) (triphenyl-phosphine and -arsine (PPh(3),AsPh(3)), diphenyl,2-pyridylphosphine (PPh(2)py), tris(4-fluorophenyl)phosphine (P(C(6)H(4)-4F)(3)), tris(2-tolyl)phosphine (P(o-tol)(3)), tris(cyclohexyl)phosphine (PCy(3))), with silver(I) thiocyanate, AgSCN are structurally and spectroscopically characterized. The 1:3 AgSCN : ER(3) complexes structurally defined (for PPh(3),AsPh(3) (diversely solvated)) take the form [(R(3)E)(3)AgX], the thiocyanate X = NCS being N-bound, thus [(Ph(3)E)Ag(NCS)]. A 1:2 complex with PPh(2)py, takes the binuclear form [(pyPh(2)P)(2)Ag()Ag(PPh(2)py)(2)] with an eight-membered cyclic core. 1:1 complexes are defined with PPh(2)py, P(o-tol)(3) and PCy(3); binuclear forms [(R(3)P)Ag()Ag(PR(3))] are obtained with P(o-tol)(3) (two polymorphs), while novel isomeric tetranuclear forms, which may be envisaged as dimers of dimers, are obtained with PPh(2)py, and, as further polymorphs, with PCy(3); these latter may be considered as extensions of the 'cubane' and 'step' forms previously described for [(R(3)E)AgX](4) (X = halide) complexes. Solvent-assisted mechanochemical or solvent-assisted solid-state synthesis methods were employed in some cases, where complexes could not be obtained by conventional solution methods, or where such methods yielded a mixture of polymorphs unsuitable for solid-state spectroscopy. The wavenumbers of the ν(CN) bands in the IR spectra are in broad agreement with the empirical rule that distinguishes bridging from terminal bonding, but exceptions occur for compounds that have a double SCN bridged dimeric structure, and replacement of PPh(3) with PPh(2)py apparently causes a significant decrease in ν(CN) to well below the range expected for bridging SCN in these structures. (31)P CP MAS NMR spectra yield additional parameters that allow a correlation between the structures and spectra.
Assuntos
Complexos de Coordenação/química , Fosfinas/química , Prata/química , Tiocianatos/química , Complexos de Coordenação/síntese química , Cristalografia por Raios X , Ligantes , Conformação MolecularRESUMO
Fundamento y Objetivo: Debido a las alteraciones observadas en la condición física de pacientes con insuficiencia renal crónica se ha demostrado la utilidad de someter a estos pacientes a un entrenamiento físico. El cociente respiratorio es utilizado normalmente como un medio no invasivo para estimar el umbral anaeróbico en sujetos sometidos a entrenamiento físico. Este estudio tuvo como objetivo evaluar la utilidad del cociente respiratorio como método indirecto para estimar el umbral anaeróbico y como indicador de detención en una ergometría en pacientes con insuficiencia renal crónica. Pacientes y método: Se realizó una cicloergometría con análisis de gases espirados en un grupo de pacientes con insuficiencia renal crónica (n=17) y en un grupo de sujetos sanos (n=18). Los cocientes respiratorios en reposo y con 30, 60 y 100 W fueron comparados entre ambos grupos. Resultados: No se observaron diferencias entre individuos sanos y pacientes en el cociente respiratorio en reposo; sin embargo, durante la prueba con diferentes intensidades de trabajo se observaron diferencias estadísticamente significativas entre ambos grupos. Conclusiones: En el caso de los nefrópatas, las diferencias observadas en el cociente respiratorio pueden atribuirse a exceso de producción de CO2. Per esta razón, la utilización del cociente respiratorio como un medio no invasivo para estimar el umbral anaeróbico parece ser no recomendable en pacientes con insuficiencia renal crónica.
Background and Objective: Due to changes observed in the physical condition of patients with chronic renal failure it has been demonstrated the usefulness of the physical training on these patients. The respiratory quotient is normally used as a non-invasive method for estimating the anaerobic threshold in subjects undergoing physical training. This study aimed to evaluate the usefulness of the respiratory quotient as an indirect method to estimate the anaerobic threshold and as an indicator to stop the ergometry in patients with chronic renal failure. Patients and Methods: We conducted a cycle-erge metry with expired gas analysis in patients with chronic renal failure (n = 17) and in a group of healthy subjects (n= 18). The respiratory quotients at rest and with 30, 60 and 100 W were compared between groups. Results: No differences in the respiratory quotient were observed between healthy subjects and patients at rest, however, statistically significant differences were found between groups with different intensities of work. Conclusions: Because the observed differences in respiratory quotients could be attributed to an excess on production of CO2 in chronic renal failure patients, the use of respiratory quotient as a non-invasive method for estimating the anaerobic threshold seems to be not recommended in these patients.
Assuntos
Humanos , Masculino , Adulto , Feminino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/fisiopatologia , Teste de Esforço/métodos , Limiar Anaeróbio/fisiologia , Estudos de Casos e Controles , Consumo de Oxigênio/fisiologia , Dióxido de Carbono/metabolismo , Insuficiência Renal Crônica/metabolismo , Troca Gasosa Pulmonar/fisiologia , Capacidade Vital , Ventilação Pulmonar/fisiologiaRESUMO
Prenatal undernutrition induces a variety of cardiovascular alterations in mammals when adults, including hypertension and hypercortisolism, which are thought to be caused by decreased glucocorticoid feedback control of the hypothalamus-pituitary-adrenal (HPA) axis programmed during fetal life. Hypothalamic CRH seems to be involved in blood pressure elevation of spontaneously hypertensive rats and in primary hypertension of humans, but the influence of prenatal undernutrition on CRH expression has deserved little attention. Here, we studied the expression of both CRH mRNA and CRH protein in the hypothalamus of neonatal and juvenile offspring of rats undernourished during fetal life, as well as the plasma levels of CRH and corticosterone. Prenatal undernutrition of pups was induced by submitting pregnant rats to diet restriction (10g daily of 21% protein standard laboratory diet). Pups born from dams with free access to the standard laboratory diet served as controls. At day 2 of postnatal age, undernourished pups showed lower body and brain weights, but higher plasma CRH and corticosterone than normal pups. At day 40 of age, brain weight was significantly decreased in the undernourished rats, while plasma corticosterone, plasma CRH and systolic pressure were significantly increased in these animals. At days 2 and 40 of postnatal age, increased CRH mRNA expression and CRH concentration were found in the hypothalamus of undernourished rats. Results indicate that, in the rat, prenatal undernutrition led to fetal programming of CRH overexpression, a neuropeptide serving as activating signal to the HPA axis and/or to extrahypothalamic brain regions concerned with cardiovascular regulation.
Assuntos
Corticosterona/sangue , Hormônio Liberador da Corticotropina/genética , Hormônio Liberador da Corticotropina/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Hipotálamo/crescimento & desenvolvimento , Hipotálamo/fisiopatologia , Desnutrição/patologia , Fatores Etários , Animais , Animais Recém-Nascidos , Peso Corporal/fisiologia , Modelos Animais de Doenças , Feminino , Masculino , Desnutrição/metabolismo , Desnutrição/fisiopatologia , Gravidez , Ratos , Ratos WistarRESUMO
Prenatal undernutrition is known to disturb the hypothalamo-pituitary-adrenal (HPA) axis, possibly through the programming of decreased expression of hypothalamic and pituitary glucocorticoid receptors. To test this hypothesis, we examined the corticosterone response to moderate subcutaneous (100 microg/kg) and intra-paraventricular (50 pmol, bilaterally) dexamethasone (DEX) challenges in normal eutrophic and prenatally undernourished young rats. Undernutrition was induced during fetal life by restricting the diet of pregnant mothers to 10 g daily, while mothers of eutrophic rats received the same diet ad libitum. At day 40 of postnatal life (i) undernourished rats showed increased plasma corticosterone concentration compared to normals; and (ii) subcutaneous and intra-paraventricular administrations of DEX led to reduced corticosterone levels in normal and undernourished animals, the effect of DEX (administered either peripherally or centrally) being significantly lower in the latter group. Results suggest that the low sensitivity of the HPA axis to DEX as well as the increased plasma corticosterone observed in prenatally undernourished rats could be due to the already reported glucocorticoid receptor underexpression found in the hypothalamus and pituitary of in utero undernourished animals, but alternative explanations involving central noradrenergic adaptive changes could also be possible.
Assuntos
Corticosterona/metabolismo , Doenças do Sistema Endócrino/fisiopatologia , Transtornos da Nutrição Fetal/fisiopatologia , Sistema Hipotálamo-Hipofisário/fisiopatologia , Sistema Hipófise-Suprarrenal/fisiopatologia , Receptores de Glucocorticoides/metabolismo , Envelhecimento/fisiologia , Animais , Animais Recém-Nascidos , Corticosterona/sangue , Dexametasona/farmacologia , Doenças do Sistema Endócrino/etiologia , Feminino , Glucocorticoides/farmacologia , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Sistema Hipotálamo-Hipofisário/metabolismo , Injeções Subcutâneas , Masculino , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Núcleo Hipotalâmico Paraventricular/metabolismo , Núcleo Hipotalâmico Paraventricular/fisiopatologia , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Sistema Hipófise-Suprarrenal/metabolismo , Gravidez , Ratos , Ratos Wistar , Receptores de Glucocorticoides/efeitos dos fármacosRESUMO
The effects of intracoerulear CRH and intraparaventricular prazosin on systolic pressure, diastolic pressure and heart rate were studied in prenatally malnourished hypertensive rats. At day 40 of life, (i) malnourished rats showed enhanced systolic pressure, heart rate, and plasma corticosterone; (ii) intracoerulear CRH increased systolic pressure and heart rate only in controls; (iii) intraparaventricular prazosin decreased systolic pressure and heart rate only in malnourished rats; (iv) in controls, prazosin did not prevent the stimulatory effect of CRH on the cardiovascular parameters; in malnourished rats, prazosin allowed CRH regain its stimulatory effects. Thus, coerulear activation by CRH would be involved in hypertension and tachycardia developed by prenatally malnourished animals.
Assuntos
Hormônio Liberador da Corticotropina/administração & dosagem , Transtornos da Nutrição Fetal/fisiopatologia , Hipertensão/tratamento farmacológico , Locus Cerúleo/fisiologia , Animais , Anti-Hipertensivos/administração & dosagem , Pressão Sanguínea/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Corticosterona/sangue , Modelos Animais de Doenças , Vias de Administração de Medicamentos , Interações Medicamentosas , Feminino , Frequência Cardíaca/efeitos dos fármacos , Locus Cerúleo/efeitos dos fármacos , Masculino , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Núcleo Hipotalâmico Paraventricular/fisiologia , Prazosina/administração & dosagem , Gravidez , Ratos , Ratos WistarRESUMO
This study describes the financial support for resarch in chile in different areas related to the productive sector including biotechology. Four different sosurce swhich help research in the country through competitive resarch grants were analysed. These include: FUNDECYT (National Fund for Resarch and Technology), Fondo de Desarrollo Productivo de CORFO (Fund for Productive Development), Fondo de Investigaciones Agropecuarias (Fund for Research in Agriculture and Livestock) and the IV Program for Technical Cooperation Between the Chilean Government and UNDP. Biotechnology appears as one of the areas related to the productive sector having an important number of projects approved with a substantial financial support. Based in a survey, recomendations are made to improve the relationship between the productive and academic sector in biotecnology and other areas
Assuntos
Biotecnologia , Pesquisa , Apoio à Pesquisa como Assunto , Chile , Projetos de PesquisaRESUMO
El efecto de corticosteroides sobre el movimiento de electrolitos fue estudiado en un modelo de saco evertido del colón distal de rata. La corticosterona tiene un significativo efecto estimulador, dependiente de la dosis, sobre la transferencia de sodio y líquido. Con la baja dosis de 10-9M la corticosterona aumentó la absorción de sodio en 29.4 micronEq g-1 h-1, valor que fue estadisticamente mayor que el efecto de dexametasona 10-9M. Con la alta concentración de 10-7M el efecto de corticosterona sobre el movimiento de sodio fue dos veces el de aldosterona o dexametasona en concentraciones equimolares. En cambio, el efecto de corticosterona sobre el movimiento de potasio fue bifásico: a baja concentración (10-9M) se encontró una significativa secreción neta, mientras que con corticosterona 10-7M se observó absorción de potasio. La dexametasona aumentó significativamente la secreción neta de potasio, mientras que el efecto de aldosterona sobre el movimiento de potasio no fue significativamente diferente de los controles. Estos datos sugieron que el glucocorticoide nativo, corticosterona, ejerce un control regulatorio de la función de los electrolitos y líquidos del colon
Assuntos
Ratos , Animais , Masculino , Colo/metabolismo , Corticosterona/farmacologia , Sódio/metabolismo , Equilíbrio Hidroeletrolítico/efeitos dos fármacos , Aldosterona/farmacologia , Dexametasona/farmacologia , Relação Dose-Resposta a DrogaRESUMO
El efecto de corticosteroides sobre el movimiento de electrolitos fue estudiado en un modelo de saco evertido del colón distal de rata. La corticosterona tiene un significativo efecto estimulador, dependiente de la dosis, sobre la transferencia de sodio y líquido. Con la baja dosis de 10-9M la corticosterona aumentó la absorción de sodio en 29.4 micronEq g-1 h-1, valor que fue estadisticamente mayor que el efecto de dexametasona 10-9M. Con la alta concentración de 10-7M el efecto de corticosterona sobre el movimiento de sodio fue dos veces el de aldosterona o dexametasona en concentraciones equimolares. En cambio, el efecto de corticosterona sobre el movimiento de potasio fue bifásico: a baja concentración (10-9M) se encontró una significativa secreción neta, mientras que con corticosterona 10-7M se observó absorción de potasio. La dexametasona aumentó significativamente la secreción neta de potasio, mientras que el efecto de aldosterona sobre el movimiento de potasio no fue significativamente diferente de los controles. Estos datos sugieron que el glucocorticoide nativo, corticosterona, ejerce un control regulatorio de la función de los electrolitos y líquidos del colon (AU)