Aging affects the response of female rats to a hypercaloric diet.

Metabolic syndrome is a major risk factor for the development of cardiovascular diseases and diabetes, among other conditions. Studies have shown that aging and metabolic syndrome share several metabolic alterations, and that aged individuals, in particular females, are at an increased risk of developing metabolic disorders. Although several studies have investigated the effects of hypercaloric diets in the development of obesity and metabolic syndrome in young animals, few studies have investigated these parameters in aged animals, especially in females. Therefore, the aim of this study was to investigate the effects of a hypercaloric diet in metabolic parameters of young and aged female rats, including its effects on lipid and glycemic profile and on liver lipid content. When compared to young animals, the aged rats presented increased serum levels of triglycerides and decreased serum levels of HDL cholesterol and glycemia, as well as increased hepatic levels of triglycerides and total cholesterol. The hypercaloric diet increased food intake, body weight gain and adiposity index, leading both young and aged animals to a dyslipidemia, represented by increased serum levels of triglycerides. The hypercaloric diet increased the glycemia and the HOMA index only in the young animals. On the other hand, the diet increased the frequency of hepatocellular microvacuolar degeneration only in the aged animals. In summary, it was observed that the females from different ages respond differently to hypercaloric diet intake: while the aged animals were more resistant to the changes in the glycemic profile, they were more susceptible to the hepatic damage caused by this diet.

Coherent electronic and nuclear dynamics in a rhodamine heterodimer-DNA supramolecular complex.

Elucidating the role of quantum coherences in energy migration within biological and artificial multichromophoric antenna systems is the subject of an intense debate. It is also a practical matter because of the decisive implications for understanding the biological processes and engineering artificial materials for solar energy harvesting. A supramolecular rhodamine heterodimer on a DNA scaffold was suitably engineered to mimic the basic donor-acceptor unit of light-harvesting antennas. Ultrafast 2D electronic spectroscopic measurements allowed identifying clear features attributable to a coherent superposition of dimer electronic and vibrational states contributing to the coherent electronic charge beating between the donor and the acceptor. The frequency of electronic charge beating is found to be 970 cm-1 (34 fs) and can be observed for 150 fs. Through the support of high level ab initio TD-DFT computations of the entire dimer, we established that the vibrational modes preferentially optically accessed do not drive subsequent coupling between the electronic states on the 600 fs of the experiment. It was thereby possible to characterize the time scales of the early time femtosecond dynamics of the electronic coherence built by the optical excitation in a large rigid supramolecular system at a room temperature in solution.

Diet-induced obesity alters memory consolidation in female rats.

Obesity is a multifactorial disease characterized by the abnormal or excessive fat accumulation, which is caused by an energy imbalance between consumed and expended calories. Obesity leads to an inflammatory response that may result in peripheral and central metabolic changes, including insulin and leptin resistance. Insulin and leptin resistance have been associated with metabolic and cognitive dysfunctions. Obesity and some neurodegenerative diseases that lead to dementia affect mainly women. However, the effects of diet-induced obesity on memory consolidation in female rats are poorly understood. Therefore, the aim of this study was to evaluate the effect of a hypercaloric diet on the object recognition memory of female rats and on possible related metabolic changes. The animals submitted to the hypercaloric diet presented a higher food intake in grams and in calories, resulting in increased weight gain and liposomatic index in comparison with the animals exposed to the control diet. These animals presented a memory deficit in the object recognition test and increased serum levels of glucose and leptin. However, no significant differences were found in the serum levels of insulin, TNF-α and IL-1ß, in the index of insulin resistance (HOMA), in the hippocampal levels of insulin, TNF-α and IL-1ß, as well as on Akt expression or activation in the hippocampus. Our findings indicate that adult female rats submitted to a hypercaloric diet present memory consolidation impairment, which could be associated with diet-induced weight gain and leptin resistance, even without the development of insulin resistance.

Electrostatically stabilized hybrids of carbon and maghemite nanoparticles: electrochemical study and application.

Binary hybrids have been investigated for the past few decades due to the emerging properties of nanoparticle composites. Electrostatically stabilized core-shell nanostructures composed of surface active magnetic nanoparticles (SAMNs) and differently charged carbon nanomaterials display specific electrochemical properties. In this work, a set of binary hybrids that include a new class of magnetic nanoparticles is presented and the electrochemical features of the hybrids are reported. Gallic acid derived carbon dots (GA-CDs), PEG derived graphene dots (PEG-GDs), and quaternized carbon dots (Q-CDs) characterized by different charged groups were used for the preparation of different complexes with SAMNs. Thus, a set of six binary nanomaterials was obtained, and characterized by electrochemical impedance spectroscopy, cyclic voltammetry and chronoamperometry, demonstrating significant differences in the charge transfer resistance, capacitive current, electrochemical performance, and reversibility with respect to the isolated subunits. Among them, the combination of Q-CDs with an excess of SAMNs led to a Q-CD@SAMN hybrid, which displayed peculiar electrocatalytic properties attributable to the influence of the strong electrostatic interactions exerted by Q-CDs on the SAMN surface. Notwithstanding their small fraction (around 1% w/w), Q-CDs oriented the electrocatalysis of SAMNs toward the selective electro-oxidation of polyphenols at low applied potentials (+0.1 V vs. SCE). Finally, the Q-CD@SAMN hybrid was used for the development of a coulometric sensor for polyphenols, composed of a simple carbon paste electrode in a small volume electrochemical flow cell (1 µL), and used for the complete direct electro-oxidation of polyphenols from plant extracts.

Neonatal handling and the expression of immunoreactivity to tyrosine hydroxylase in the hypothalamus of adult male rats

Neonatal handling has long-lasting effects on behavior and stress reactivity. The purpose of the present study was to investigate the effect of neonatal handling on the number of dopaminergic neurons in the hypothalamic nuclei of adult male rats as part of a series of studies that could explain the long-lasting effects of neonatal stimulation. Two groups of Wistar rats were studied: nonhandled (pups were left undisturbed, control) and handled (pups were handled for 1 min once a day during the first 10 days of life). At 75-80 days, the males were anesthetized and the brains were processed for immunohistochemistry. An anti-tyrosine hydroxylase antibody and the avidin-biotin-peroxidase method were used. Tyrosine hydroxylase-immunoreactive (TH-IR) neurons were counted bilaterally in the arcuate, paraventricular and periventricular nuclei of the hypothalamus in 30-æm sections at 120-æm intervals. Neonatal handling did not change the number of TH-IR neurons in the arcuate (1021 + or - 206, N = 6; 1020 + or - 150, N = 6; nonhandled and handled, respectively), paraventricular (584 + or - 85, N = 8; 682 + or - 62, N = 9) or periventricular (743 + or - 118, N = 7; 990 + or - 158, N = 7) nuclei of the hypothalamus. The absence of an effect on the number of dopaminergic cells in the hypothalamus indicates that the reduction in the amount of neurons induced by neonatal handling, as shown by other studies, is not a general phenomenon in the brain

Neonatal handling and the expression of immunoreactivity to tyrosine hydroxylase in the hypothalamus of adult male rats.

Neonatal handling has long-lasting effects on behavior and stress reactivity. The purpose of the present study was to investigate the effect of neonatal handling on the number of dopaminergic neurons in the hypothalamic nuclei of adult male rats as part of a series of studies that could explain the long-lasting effects of neonatal stimulation. Two groups of Wistar rats were studied: nonhandled (pups were left undisturbed, control) and handled (pups were handled for 1 min once a day during the first 10 days of life). At 75-80 days, the males were anesthetized and the brains were processed for immunohistochemistry. An anti-tyrosine hydroxylase antibody and the avidin-biotin-peroxidase method were used. Tyrosine hydroxylase-immunoreactive (TH-IR) neurons were counted bilaterally in the arcuate, paraventricular and periventricular nuclei of the hypothalamus in 30-microm sections at 120-microm intervals. Neonatal handling did not change the number of TH-IR neurons in the arcuate (1021 +/- 206, N = 6; 1020 +/- 150, N = 6; nonhandled and handled, respectively), paraventricular (584 +/- 85, N = 8; 682 +/- 62, N = 9) or periventricular (743 +/- 118, N = 7; 990 +/- 158, N = 7) nuclei of the hypothalamus. The absence of an effect on the number of dopaminergic cells in the hypothalamus indicates that the reduction in the amount of neurons induced by neonatal handling, as shown by other studies, is not a general phenomenon in the brain.

Effects of xenoestrogen bisphenol A on uterine and pituitary weight, serum prolactin levels and immunoreactive prolactin cells in ovariectomized Wistar rats.

Considerable attention has currently been focused on bisphenol A (BPA), an environmental endocrine disrupting chemical that has oestrogenic activity. In vitro and in vivo short-term assays have shown that BPA is weakly estrogenic. In addition, the issue of species- and strain-differences in susceptibility to BPA was raised. The treatment of ovariectomized (OVX) Wistar rats with BPA at doses of 11-250 mg/kg per day, s.c., for 7 days, resulted in significant dose-dependent regrowth of uterus in uterotrophic assay. Additionally, the stimulation of anterior pituitary gland growth and induction of hyperprolactinaemia, as determined by wet organ weight and radioimmunoassay (RIA), respectively, were also dose-dependent (at 128 and 250 mg/kg per day, P < 0.05). Prolactin immunostaining of anterior pituitary glands revealed that BPA at a dose of 250 mg/kg per day increased the number of prolactin-immunopositive cells by 63% compared to OVX rats. These results demonstrate that the reproductive tract and neuroendocrine axis of Wistar rats are able to respond to BPA. Furthermore, the pituitary gland hypertrophy and hyperprolactinaemia can be mediated, at least partly, by increase in number of prolactin-immunoreactive cells. The long-term consequences of this proliferation are yet unknown but neoplasm formation is an obvious possibility.