153 resultados para Hypoxia, stemness


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In female rats, a single injection of estradiol valerate (EV) results in effects that are similar to those observed in women with polycystic ovary syndrome (PCOS). We hypothesized that EV-induced PCOS affects breathing control based on evidence showing an influence of sex hormones on ventilation. To test this hypothesis, we studied the effects of EV treatment on the ventilation of female rats in air, in 7% CO2 and in 7% O2, at 30, 45 and 60 days after EV injection. The group examined 30 days after EV treatment showed a 61% reduction in the hypercapnic ventilatory response compared to the control group. Basal ventilation, hypoxic ventilatory response, and body temperature were not affected. These results, suggest that the hormonal changes observed in PCOS may result in a temporary inhibition of the central chemoreflex but do not influence basal ventilation or the hypoxic peripheral chemoreflex.

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Condition of hypoxia caused by hypertrophy of adipose cells in obesity triggers macrophages recruitment and production of cytokines. Additionally, high consumption of saturated fatty acids (SFA) and high glycemic index meals may contribute to oxidative stress and chronic low-grade inflammation by increases NF-kB activation. Thus, the aim of the study was to analyze the contribution of the macronutrients intake in the metabolic and inflammatory profile, by levels of lipoproteins, insulin resistance, anti and pro inflammatory cytokines, in obese adolescents according the gender. sample was composed by 37 adolescents, both genders, identified as obese by body mass index (BMI). Body composition was assessed by Dual-energy X-ray absorptiometry (DEXA) and measures of intra-abdominal adiposity (IAAT) and subcutaneous adiposity tissue (SAT) were done by ultrasound. Biochemical analyses were done and the measurement of cytokines; fatty acids and insulin were performed by the technique of immunoassay ELISA. The estimation of macronutrients consumption was made by 3 day food register regarding food intake. Statistical significance was set at p-value < 5% and the statistical software SPSS version 17.0 (SPSS Inc, Chicago, IL) performed all analyses. BMI (p = 0.316), FM (p = 0.416), IAAT (p = 0.505) and SAT (p = 0.935) presented similarities between genders. Cytokines and metabolic variables values were similar between the groups. Only in the male group, metabolic variables and cytokines were significant correlated with the consumption of total lipids or its fractions. Was observed that insulin concentration had significant interaction with MUFA(g) (= -18.4; p = 0.004) and adiponectin with CHO(g) (= -58.2; p = 0.032) in the group male and female, respectively. macronutrients intake is associated with low-grade inflammation in obesity, by production of inflammatory cytokines and alteration of the lipid profile, especially male obese adolescents which seem to be more responsive of this consumption when compared with female obese adolescents.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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1. Respiratory rates of workers of the leaf cutting ant Atta sexdens rubropilosa were measured at different oxygen pressures, at 25°C. 2. In experiments where different ants were used at each of the oxygen pressures, respiration was regulated down to 70.8 mmHg. 3. When the same ants were submitted in sequence to declining pO2, the 'oxygen dependence indexes' (Tang P.S. (1933) Quart. Rev. Biol. 8, 260-274) also suggested a good regulatory capacity. 4. The results are discussed in terms of the variation of the partial pressures of O2 and CO2 that the ants probably encounter when wandering to and from the nest to forage, and when performing their heavy tasks (leaf transport, offspring and fungus care). 5. CO2 rise and O2 fall, from ants' respiration inside the ant hill, may act as the factors that, in a reflex way, keep the spiracles open and increase ventilation and the frequency of CO2 emission to keep the oxygen supply adequate to face the energetic demand of the routine level of activity of the workers, when passing from normoxia (air) to hypoxia (in nest galleries).

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1. 1. Oxygen consumption and its relationship to declining oxygen tension was examined in the tropical spirotreptid millipede, Plusioporus setiger. 2. 2. At 25°C and normoxia, the allometric equations relating the weight-specific oxygen consumption rates and body weight were V ̇O2 = 2.1266 × W-53 for males, and V ̇O2 = 2.0915 × W-64 for females, but no significant difference was detected from the b-values. 3. 3. Plusioporus setiger regulated respiration down to 35.40 mmHg O2 when suddenly exposed to a lowered oxygen tension, or 17.70 mmHg O2, when examined in a stepwise declining oxygen tension. 4. 4. O2 dependence indices ( K1 K2) were relatively low, also expressing regulation, but no relation to size (weight) was recorded. 5. 5. After exposure to hypoxia, P. setiger showed a typical pattern of under repayment, on the return to normoxia. © 1987.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Aim To analyse the local regulatory mechanisms of osteoclastogenesis and angiogenesis during the progression of periapical lesions in female rats with oestrogen deficiency and treatment with raloxifene (RLX). Methodology Female Wistar rats were distributed into groups: SHAM-veh, subjected to sham surgery and treated with a vehicle; OVX-veh, subjected to ovary removal and treated with a vehicle; and OVX-RLX, subjected to ovary removal and treated with RLX. Vehicle or RLX was administered orally for 90 days. During treatment, the dental pulp of mandibular first molars was exposed to the oral environment for induction of periapical lesions, which were analysed after 7 and 30 days. After the experimental periods, blood samples were collected for measurement of oestradiol, calcium, phosphorus and alkaline phosphatase. The rats were euthanized and the mandibles removed and processed for immunohistochemical detection of receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG), hypoxia-inducible factor-1 alpha (HIF-1α) and bone-specific alkaline phosphatase (BALP). Data were compared using Kruskal–Wallis followed by Dunn test (nonparametric values) and anova followed by the Tukey's test (parametric values). Results The plasma concentration of oestradiol showed hypo-oestrogenism in the rats subjected to ovary removal. On day 7, alkaline phosphatase activity, calcium and phosphorus were higher in the OVX-RLX group than in the OVX-veh group (P < 0.001), but immunolabelling for RANKL and HIF-1α was lower in OVX-RLX group (P < 0.001). On day 30, the OVX-veh group had higher immunolabelling for RANKL than the OVX-RLX group (P < 0.05). There were no significant differences in the immunoreactivity of OPG and BALP between any groups at either time-point (P > 0.05). Conclusion RLX therapy reversed the increased levels of the local regulators of both osteoclastogenesis and angiogenesis induced by oestrogen deficiency.

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Enhanced sympathetic outflow to the heart and resistance vessels greatly contributes to the onset and maintenance of neurogenic hypertension. There is a consensus that the development of hypertension (clinical and experimental) is associated with an impairment of sympathetic reflex control by arterial baroreceptors. More recently, chronic peripheral chemoreflex activation, as observed in obstructive sleep apnea, has been proposed as another important risk factor for hypertension. In this review, we present and discuss recent experimental evidence showing that changes in the respiratory pattern, elicited by chronic intermittent hypoxia, play a key role in increasing sympathetic activity and arterial pressure in rats. This concept parallels results observed in other models of neurogenic hypertension, such as spontaneously hypertensive rats and rats with angiotensin II–salt-induced hypertension, pointing out alterations in the central coupling of respiratory and sympathetic activities as a novel mechanism underlying the development of neurogenic hypertension.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)