Gaussian and Gaussian-pulsed-like Fermi velocity graphene structures.

Gaussian and Gaussian-related structures are quite attractive due to its versatility to modulate the electronic transport, including its possibility as electron filters. Here, we show that these non-conventional profiles are not the exception when dealing with Fermi velocity barriers in monolayer graphene. In particular, we show that Gaussian Fermi velocity graphene barriers (G-FVGBs) and Gaussian-pulsed-like Fermi velocity graphene superlattices (GPL-FVGSLs) can serve as electron band-pass filters and oscillating conductance structures. We reach this conclusion by theoretically studying the transmission and transport properties of the mentioned structures. The study is based on the continuum model, the transfer matrix method and the Landauer-Büttiker formalism. We find nearly flat transmission bands or pass bands for G-FVGBs modulable through the system parameters. The pass bands improve as the maximum ratio of Fermi velocities (ξmax) increases, however its omnidirectional range is reduced. These characteristics result in a decaying conductance (integrated transmission) withξmax. The integrated transmission remains practically unaltered with the size of the system due to the saturation of the electron pass band filtering. In the case of GPL-FVGSLs the GPL profile results in regions of high transmission probability that can merge as flat transmission minibands if the pulse fraction and the superlattice parameters are appropriately tuned. The GPL profile also results in conductance (integrated transmission) oscillations that can be multiplied or reduced in number by adjusting the pulse fraction as well as the superlattice parameters.

Involvement of mast cells, CD68+ and VEGF+ expressions in response to Himatanthus drasticus commercial latex in mice wound healing model / Envolvimento de mastócitos, expressão de CD68+ e VEGF+ em resposta ao látex comercial de Himatanthus drasticus em modelo de cicatrização em camundongos

This study aimed to evaluate Himatanthus drasticus latex in a mice wound healing experimental model. Animals were divided into four groups (n=7) according to the treatments: GI - saline 0.9% (control), GII - mineral oil (vehicle), GIII - H. drasticus commercial latex (HdCL) and GIV - H. drasticus mixed isolated fraction (MIF, 1 mg/mL). The treatments were applied topically once daily, 50 µL for 14 consecutive days. Macroscopic lesions were evaluated, considering parameters such as swelling, redness, granulation tissue and reepithelialization. VEGF+, CD68+ expressions and mast cells (Toluidin blue stain) were evaluated. HdCL induced higher contraction and exuberant granulation tissue (P > 0.05). HdCL showed a mild inflammatory process while MIF induced intense infiltrate inflammatory predominantly by lymphocytes, vascular congestion, bleeding and did not presented full reepithelialization. Reorganization of collagen fibers (red picrosirius stain) was observed. CD68+ expression and mast cells were presented as moderate, intense and mild in GI, GIII and GIV, respectively. Neovascularization occurred in all groups, while VEGF+ expression was intense in MIF in relation to HdCL. We concluded that HdCL presents wound healing potential, through modulation of mast cells, CD68+ and VEGF+ expressions that can be associated to triterpenes presence according MIF isolated from HdCL.(AU)

Objetivou-se avaliar o látex de Himatanthus drasticus em feridas induzidas experimentalmente em camundongos. Os animais foram divididos em quatro grupos (n=7): GI - salina 0,9% (controle), GII - óleo mineral (veículo), GIII - látex comercial de H. drasticus (HdCL) e GIV - fração isolada mista de H. drasticus (MIF, 1mg/mL). Os tratamentos foram aplicados topicamente uma vez ao dia (50µL), durante 14 dias consecutivos. Lesões macroscópicas, as expressões de VEGF+, CD68+ e a participação dos mastócitos (coloração azul de toluidina) foram avaliadas. HdCL induziu maior contração e tecido de granulação exuberante (P >0,05). HdCL induziu leve processo inflamatório enquanto MIF promoveu intenso infiltrado inflamatório predominantemente linfocítico, congestão vascular, hemorragia e reepitelização parcial. Observou-se reorganização das fibras colágenas (coloração picrosírius). A expressão de CD68+ e os mastócitos apresentaram-se moderados, intensos e leves em GI, GIII e GIV, respectivamente. A neovascularização foi observada em todos os grupos, enquanto a expressão de VEGF+ foi mais intensa em MIF em relação a HdCL. Conclui-se que HdCL apresenta potencial de cicatrização por meio da modulação dos mastócitos e das expressões de CD68+ e VEGF+, o que pode estar associado à presença de triterpenos de acordo com MIF isolada de HdCL.(AU)

Cafeteria diet inhibits insulin clearance by reduced insulin-degrading enzyme expression and mRNA splicing.

Insulin clearance plays a major role in glucose homeostasis and insulin sensitivity in physiological and/or pathological conditions, such as obesity-induced type 2 diabetes as well as diet-induced obesity. The aim of the present work was to evaluate cafeteria diet-induced obesity-induced changes in insulin clearance and to explain the mechanisms underlying these possible changes. Female Swiss mice were fed either a standard chow diet (CTL) or a cafeteria diet (CAF) for 8 weeks, after which we performed glucose tolerance tests, insulin tolerance tests, insulin dynamics, and insulin clearance tests. We then isolated pancreatic islets for ex vivo glucose-stimulated insulin secretion as well as liver, gastrocnemius, visceral adipose tissue, and hypothalamus for subsequent protein analysis by western blot and determination of mRNA levels by real-time RT-PCR. The cafeteria diet induced insulin resistance, glucose intolerance, and increased insulin secretion and total insulin content. More importantly, mice that were fed a cafeteria diet demonstrated reduced insulin clearance and decay rate as well as reduced insulin-degrading enzyme (IDE) protein and mRNA levels in liver and skeletal muscle compared with the control animals. Furthermore, the cafeteria diet reduced IDE expression and alternative splicing in the liver and skeletal muscle of mice. In conclusion, a cafeteria diet impairs glucose homeostasis by reducing insulin sensitivity, but it also reduces insulin clearance by reducing IDE expression and alternative splicing in mouse liver; however, whether this mechanism contributes to the glucose intolerance or helps to ameliorate it remains unclear.

Ciliary neurotrophic factor (CNTF) protects non-obese Swiss mice against type 2 diabetes by increasing beta cell mass and reducing insulin clearance.

AIMS/HYPOTHESIS: Ciliary neurotrophic factor (CNTF) improves metabolic variables of obese animals with characteristics of type 2 diabetes, mainly by reducing insulin resistance. We evaluated whether CNTF was able to improve other metabolic variables in mouse models of type 2 diabetes, such as beta cell mass and insulin clearance, and whether CNTF has any effect on non-obese mice with characteristics of type 2 diabetes. METHODS: Neonatal mice were treated with 0.1 mg/kg CNTF or citrate buffer via intraperitoneal injections, before injection of 250 mg/kg alloxan. HEPG2 cells were cultured for 3 days in the presence of citrate buffer, 1 nmol/l CNTF or 50 mmol/l alloxan or a combination of CNTF and alloxan. Twenty-one days after treatment, we determined body weight, epididymal fat weight, blood glucose, plasma insulin, NEFA, glucose tolerance, insulin resistance, insulin clearance and beta cell mass. Finally, we assessed insulin receptor and protein kinase B phosphorylation in peripheral organs, as well as insulin-degrading enzyme (IDE) protein production and alternative splicing in the liver and HEPG2 cells. RESULTS: CNTF improved insulin sensitivity and beta cell mass, while reducing glucose-stimulated insulin secretion and insulin clearance in Swiss mice, improving glucose handling in a non-obese type 2 diabetes model. This effect was associated with lower IDE production and activity in liver cells. All these effects were observed even at 21 days after CNTF treatment. CONCLUSIONS/INTERPRETATION: CNTF protection against type 2 diabetes is partially independent of the anti-obesity actions of CNTF, requiring a reduction in insulin clearance and increased beta cell mass, besides increased insulin sensitivity. Furthermore, knowledge of the long-term effects of CNTF expands its pharmacological relevance.

Antiácido de alta potência versus cimetidina no tratamento da úlcera duodenal: comodidade posológica / High potency antacid versus cometidine in the treatment of duodenal ulcer: commodus psosology

Foram estudados 98 pacientes com úlcera péptica duodenal distribuídos de forma randômica em dois grupos. Um grupo recebeu antiácido liquido de alta potência (282,4mEq/dia) dividido em 4 tomadas durante 4 semanas e outro recebeu cimetidina (800 mg/dia) dividida em 2 tomadas por igual período. A potência antiácida da associaçäo líquida utilizada é de 7,06 mEq/ml. Todos os pacientes foram avaliados clinicamente no pré-tratamento e duas e quatro semanas após, com exames endoscópicos realizados na admissäo e após quatro semanas. A eficácia, considerada como cicatrizaçäo da úlcera duodenal associada a melhora da sintomatologia foi equivalente para ambos os tratamentos, näo havendo diferença estatisticamente significante. A tolerabilidade de ambas as drogas foi considerada boa