da Silva M.P.,University of Sao Paulo |
Ventura R.R.,Federal University of Alfenas |
Varanda W.A.,University of Sao Paulo
Neuroscience | Year: 2013
Increases in plasma osmolality enhance nitric oxide (NO) levels in magnocellular neurosecretory cells (MNCs) of the supraoptic nucleus (SON) and modulate the secretion of both vasopressin (VP) and oxytocin (OT). In this paper, we describe the effects of hypertonicity on the electrical properties of MNCs by focusing on the nitrergic modulation of their activity in this condition. Membrane potentials were measured using the patch clamp technique, in the presence of both glutamatergic and GABAergic neurotransmission blockers, in coronal brain slices of male Wistar rats. The recordings were first made under a control condition (295mosm/kg H2O), then in the presence of a hypertonic stimulus (330mosm/kg H2O) and, finally, with a hypertonic stimulus plus 500μM l-Arginine or 100μM N-nitro-l-Arginine methyl ester hydrochloride (l-NAME). Hypertonicity per se increased the firing frequency of the neurons. l-Arginine prevented the increase in fire frequency induced by hypertonic stimulus, and l-NAME (inhibitor of nitric oxide synthase) induced an additional increase in frequency when applied together with the hypertonic solution. Moreover, l-Arginine hyperpolarizes the resting potential and decreases the peak value of the after-hyperpolarization; both effects were blocked by l-NAME and hypertonicity and/or l-NAME reduced the time constant of the rising phase of the after-depolarization. These results demonstrate that an intrinsic nitrergic system is part of the mechanisms controlling the excitability of MNCs of the SON when the internal fluid homeostasis is disturbed. © 2013 IBRO.
De Faria A.J.,Federal University of Alfenas
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2016
The average fidelity of the teleportation of coherent states is calculated for general Gaussian bipartite systems shared by the partners of the protocol, Alice and Bob. It is considered that the shared Gaussian bipartite modes suffer independent attenuations before the processing of Alice and Bob. In addition, the classical communication between the partners can be controlled by a gain not necessarily unitary. Comparing with the classical fidelity threshold of measure-and-prepare methods, we establish several genuinely quantum teleportation conditions which depend on the gain and the local attenuations. If the gain can be tuned to maximize the bipartite state set capable of performing genuinely quantum teleportation, then a condition for teleportation robust against local attenuations is found. This condition is demonstrated to be essentially equivalent to the condition of robust Gaussian bipartite entanglement, obtained in previous articles, showing that the robustness against attenuations is an entanglement property relevant for characterization and application of bipartite systems. For the derivation of the robust teleportation conditions, the Gaussian operations onto the bipartite system are thoroughly studied, so that the transformations that maintain the fidelity invariant are found. Some scenarios for different Gaussian bipartite states are presented and discussed. © 2016 American Physical Society.
Pereira W.,Federal University of Alfenas |
Camps I.,Federal University of Alfenas
Current Pharmaceutical Design | Year: 2016
Background: Chronic myelogenous leukemia is associated with hematopoietic stem cells that are manifested primarily with expansion myelopoiesis. It is the first cancer directly associated with a genetic abnormality. Specifically, it is associated to a particular cytogenetic abnormality, known as Philadelphia chromosome (Ph), which results from a fusion between part of the BCR (“breakpoint cluster region”) gene from chromosome 22 and the Abelson (ABL) gene on chromosome 9 and leads to the formation a new gene leukemia-specific, the BCR-ABL. Since 2011, there are several tyrosine-kinase inhibitors in the market. Due to mutations in the tyrosine-kinase domain, these inhibitors are becoming less effective in the leukemia treatment, and then there is a need for new more effective inhibitors. Methods: The aim of this work is to obtain new tyrosine-kinase inhibitors using in silico tools like de novo drug design, docking and absorption, distribution, metabolism and excretion studies. Results: Using the proposed methodology, an initial library of more than 6000 molecules was obtained. This library was then filtered out using the Tanimoto metric to compute the similarity between the molecules using as parameter the 2D linear hashed fingerprint with a 64-bit address space. The resulting library was then used to run docking studies together with the reference market drugs and their ADME (absorption, distribution, metabolism and excretion) properties were determined. Three compounds with better inhibition capacity and better ADME properties that the commercially available not only for the wild form of enzymes under study but also to its mutated forms were obtained. Conclusion: The fragment based drug design method used in this work turns to be a good alternative to create new drugs that can control this neoplasm. Based on the calculated GScore, the de novo designed molecules have better inhibitor capacity than the tyrosine-kinase inhibitors most used in the market. These molecules shown strong potential to become drugs capable to inhibit all mutations, mainly the T315I mutation, now the leading cause of deaths due to the difficulty of inhibitors to control it. © 2016 Bentham Science Publishers.
Morbec J.M.,Federal University of Alfenas |
Rahman G.,Quaid-i-Azam University
Physical Review B - Condensed Matter and Materials Physics | Year: 2013
Using ab initio calculations based on density functional theory, we investigate the effects of vacancies on the electronic and magnetic properties of zigzag SiC nanoribbons (Z-SiCNR). Single (VC and VSi) and double (VSiVSi and VSiVC) vacancies are observed to induce magnetism in Z-SiCNRs. The presence of a single VSi does not affect the half-metallic behavior of pristine Z-SiCNRs; however, a single VC leads to a transition from half-metallic to metallic behavior in Z-SiCNRs due to the edge Si p orbitals and the atoms surrounding the vacancy. The interactions of vacancies with foreign impurity atoms (B and N) are also investigated, and it is observed that V SiNC not only suppresses the oscillatory type magnetism of VSiVC but also retains the half-metallic character of the pristine Z-SiCNRs. The defect formation energies of vacancies can be reduced by substitutional B and N atoms. We believe that ferromagnetism is expected if Z-SiCNRs are grown under suitable conditions. © 2013 American Physical Society.
Dias K.S.T.,Federal University of Alfenas |
Viegas C.,Federal University of Alfenas
Current Neuropharmacology | Year: 2014
Alzheimer’s disease (AD) is a complex neurodegenerative disorder with a multi-faceted pathogenesis. So far, the therapeutic paradigm “one-compound-one-target” has failed and despite enormous efforts to elucidate the pathophysiology of AD, the disease is still incurable. The multiple factors involved in AD include amyloid aggregation to form insoluble neurotoxic plaques of Aβ, hyperphosphorylation of tau protein, oxidative stress, calcium imbalance, mitochondrial dysfunction and deterioration of synaptic transmission. These factors together, accentuate changes in the CNS homeostasis, starting a complex process of interconnected physiological damage, leading to cognitive and memory impairment and neuronal death. A recent approach for the rational design of new drug candidates, also called multitarget-directed ligand (MTDL) approach, has gained increasing attention by many research groups, which have developed a variety of hybrid compounds acting simultaneously on diverse biological targets. This review aims to show some recent advances and examples of the exploitation of MTDL approach in the rational design of novel drug candidate prototypes for the treatment of AD. © 2014 Bentham Science Publishers.
Vilela F.C.,Federal University of Alfenas |
Giusti-Paiva A.,Federal University of Alfenas
Endocrinology | Year: 2011
The influence of glucocorticoids on the neuroendocrine system and behavior of lactating rats is not well known. To evaluate the effects of glucocorticoids on the neuroendocrine system and maternal and aggressive behavior, lactating female rats were treated with dexamethasone or vehicle for 2 h before experiments. Blood samples were collected 15 min after the beginning of suckling to evaluate hormonal changes. To evaluate the maternal behavior of lactating rats, eight pups were placed in their home cages on the side opposite the location of the previous nest, and the resulting behavior of the lactating rat was filmed for 30 min. Aggressive behavior was evaluated by placing a male rat (intruder) in the home cage. Dexamethasone treatment reduced oxytocin and prolactin secretion during lactation and reduced pup weight gain. Relative to control treatment, dexamethasone treatment also adversely affected a variety of maternal behaviors; it increased the latency to build a new nest, decreased the number of pups gathered to the nest, increased the latency to retrieve the first pup, and decreased the percentage of time spent in the arched-nursing position. Dexamethasone treatment, compared with control, also reduced aggressive behavior, as evidenced by an increase in the latency to the first attack, a reduction in the number of front and side attacks, and a decrease in lateral threat and biting. Taken together, our results suggest dexamethasone treatment in lactating rats disrupts prolactin and oxytocin secretion, and this is followed by an attenuation of maternal and aggressive behavior. Copyright © 2011 by The Endocrine Society.
de Carvalho B.C.,Federal University of Alfenas
The International journal of oral & maxillofacial implants | Year: 2013
This 15-year prospective study evaluated the success rate and preservation of the gingival margin of single implants placed in a flapless procedure loaded immediately after extraction or after a healing period. Immediate flapless implant placement was performed in patients who fulfilled specified inclusion criteria. Implants were either immediately restored with a provisional crown or left unloaded (received healing abutment only). Implant success and gingival margin levels were evaluated after implant placement and after 1 to 15 years. A total of 305 healthy nonsmoking subjects (90 men, 215 women) were treated with 430 immediate implants during a 15-year period (December 1994 to December 2009) and monitored for 1 to 15 years. Two hundred seventy-five implants received an immediate provisional crown, and 155 received a healing abutment. The implant survival rate was 93.03% (± 3.74%). The immediate provisional helped to maintain the original gingival margin, although the implant survival rate was higher for implants that were not immediately restored (96.78%) than for the implants that were immediately restored with a provisional (90.9%). This 15-year prospective study showed a favorable implant success rate related to the flapless immediate implant placement protocol with healing abutment placement or an immediate provisional crown to replace a single missing tooth.
Clerici M.T.P.S.,Federal University of Alfenas |
Carvalho-Silva L.B.,Federal University of Alfenas
Food Research International | Year: 2011
Brazil is one of the three major fruit producers in the world. Native and/or exotic Brazilian fruits have great nutritional and economic potential. Eggfruit, blackberry, Brazilian guava, atemoya, bacuri, sweetsop, starfruit, feijoa, cactus pear, fruit of wolf, breadfruit, jaboticaba, jackfruit, rose apple, lychee, mangaba and marolo are already present in the Brazilian diet, but they are not yet industrialized and are minor agricultural products. These fruits are produced and used in the manufacture of handicraft products such as jellies and sweets that are available in free markets, but production is small-scale and without safe operational procedures. These fruits are seasonal with large postharvest losses. Thus, it is necessary to initiate competitive agribusinesses in the producing regions for these fruits to enhance local economies. This review summarizes the major nutritional and bioactive compounds found in these fruits, the technological aspects of their cultivation, and future prospects for introducing consumption of these fruits and their respective products to Brazilian and/or foreign markets. © 2011 Elsevier Ltd.
Vilela F.C.,Federal University of Alfenas |
Giusti-Paiva A.,Federal University of Alfenas
Behavioural Brain Research | Year: 2014
It has been shown that the endocannabinoid system is involved in the neurohypophyseal hormone secretion produced by exposure to several different stimuli; however, the influence of this system on neuroendocrine responses during lactation is unclear. Therefore, the aim of our study was to investigate the influence of an acute peripheral administration of WIN55,212-2 (cannabinoid receptor agonist) on behavioral and neuroendocrine responses during lactation. On day 6 of lactation, female rats were treated with vehicle or WIN55,212-2 30. min before the start of our experiments. To evaluate maternal behavior, the pups were returned to their home cages to the side of the cage opposite the previous nest, and the resulting behavior of the lactating rats was recorded for the next 30. min. Aggressive behavior was evaluated for 10. min following the placement of an intruder male rat in the home cage. The plasma level of oxytocin and the amount of milk consumption by the pups were evaluated 15. min after the onset of suckling. In addition, double-labelled c-Fos/oxytocin neurons in the medial magnocellular subdivision of the paraventricular nucleus and in the supraoptic nucleus were quantified for each lactating rat. The results show that WIN decreased maternal care, decreased aggressive behaviors, suppressed maternal anxiolysis, decreased plasma oxytocin levels and milk consumption by pups and decreased activation of oxytocinergic neurons in hypothalamic nuclei. Our results indicate that the changes in the behavioral responses of lactating rats treated with WIN maybe can be related to disruption in the neuroendocrine control of oxytocin secretion. © 2014 Elsevier B.V.
Ribeiro-Junior N.V.,Federal University of Alfenas
The International journal of periodontics & restorative dentistry | Year: 2013
Excessive gingival display during smiling ("gummy smile") is an esthetic issue that affects a considerable part of the population. The hyperactivity of the elevator muscle of the upper lip is one of the main causes of a gummy smile, and several techniques have been proposed for its treatment. The aim of this report is to describe a modification of the lip repositioning technique to achieve stable and significant outcomes through a more conservative procedure. Two patients complaining about a gummy smile were treated with the proposed technique and presented, after a 6-month follow-up, significant improvement in the amount of gingival exposure and esthetic satisfaction.