Effect of surfactants on the functional properties of gelatin-polysaccharide-based films

The aim of this study was to evaluate the effects of the addition of surfactants sodium stearoyl lactate (SSL) and sucrose ester (SE) on the functional properties of films produced with polysaccharides mixtures (methylcellulose/glucomannan/pectin in 1/4/1 ratio, respectively) and gelatin. The films were produced by the casting method and characterized for their water vapor permeability (WVP), mechanical (tensile strength and elongation to break point), morphological and optical properties. Films with low WVP were obtained with surfactants. Addition of SE to the films with polysaccharide/gelatin ratio of 90/10 showed improved mechanical properties. Films presented smooth surfaces with micro voids and lumpiness, depending on the surfactant tested. Surfactants increased the opacity of the films by a factor of 1-3%. All film properties were dependent on the surfactant affinity for the biopolymer matrix. SE presented more affinity for biopolymer matrix containing high polysaccharide proportion, and SSL presented more affinity for polymer matrix containing high gelatin proportion. The addition of surfactants decreased the water vapor permeability of the films, increasing their hydrophobic character.

Effect of orlistat on cardiovascular disease risk in obese adults

Aim: The aim of this study is to compare the effect of orlistat vs. placebo on the predicted 10-year cardiovascular disease (CVD) risk in obese people with one or more cardiovascular risk factors treated for 12 months, in conjunction with a fat-reduced, but otherwise ad libitum, diet.

Methods: A double-blind, randomized, placebo-controlled, parallel study was performed in conjunction with a fat-reduced diet and physical activity advice for 1 year. Participants (n = 339) from eight centres in Australia and New Zealand were randomized to either orlistat (120 mg) three times daily (n = 104 women, 66 men; mean ± s.d. age = 52.0 ± 7.5 years, body mass index (BMI) = 37.6 ± 5.1 kg/m2) or placebo three times daily (n = 89 women, 80 men; age = 52.5 ± 7.4 years, BMI = 38.0 ± 4.9 kg/m2). The primary efficacy criterion was the 10-year risk of developing CVD calculated from the Framingham equation. Secondary efficacy criteria were body weight, waist circumference, blood pressure and serum concentrations of triglycerides, cholesterol (total, LDL and HDL), glucose, insulin and glycated haemoglobin and quality of life.

Results: There was no difference in the change in 10-year CVD risk between orlistat and placebo groups over 1 year. The orlistat group, however, had significant favourable changes in many of the individual CVD risk factors (total cholesterol, LDL-cholesterol, glucose, glycated haemoglobin, insulin, body weight and waist circumference) and one of the domains of quality of life measured by means of the SF-36 questionnaire (vitality), compared to the placebo group. Significant reductions in medication use for hypertension and diabetes were observed in the orlistat group, compared to those in placebo, but there were no significant differences in medication use for blood lipids.

Conclusions: Orlistat may have reduced CVD risk, as judged by the favourable changes in individual risk factors and reductions in medication use, but the method used in order to measure absolute CVD risk in this study (Framingham CVD equation) was not sensitive enough to detect the changes in this relatively low-risk group (approximately 10% of risk of a CVD event over 10 years).

The effect of hydrogenation on the ECAP compaction of Ti–6Al–4V powder and the mechanical properties of compacts

The effect of hydrogen content on the compaction of Ti–6Al–4V powder at low temperatures, namely 500 °C, using equal channel angular pressing (ECAP) with back pressure has been investigated. The properties of the compacts before and after a heat treatment and de-hydrogenation cycle have been determined. Compaction of powder by ECAP (500 °C and 260 MPa) has shown maximum levels of relative density of 99.3% and 99.4% when charged with 0.05–0.1 wt.% and 0.61–0.85 wt.% of hydrogen, respectively. After the de-hydrogenation heat treatment the diffusion bonding between individual powder particles was completed and the microstructure was altered, depending on the level of hydrogen content. Two local maxima of 99.2% and 98.1% were observed in the measured density of consolidated compacts for hydrogen contents between 0.05 wt.% and 0.1 wt.% and between 0.61 wt.% and 0.85 wt.%, respectively. However, the mechanical properties of the compacts within these two ranges of hydrogen content were significantly different due to a difference in the observed microstructure. An exceptionally high ductility of 29%, in combination with a relatively high strength of ~560 MPa, was measured in a shear punch test on specimens which had a prior hydrogen level of 0.05 wt.% before the heat treatment. It was shown that material consolidated from powder hydrogenated to low levels of hydrogen before compaction has the potential to offer substantial improvements in mechanical properties after a suitable heat treatment.

Effect of plasma on the properties of protein fibres

Atmospheric pressure plasma with a relatively short exposure time was sufficient to modify the wool surface. The ageing studies showed the hydrophobic recovery of fibre surface took place at the early stages after plasma treatment. While plasma improved wool shrink-resistance, improvement in dyeability depends on the hydrophilic-hydrophobic nature of dyestuff.

Stability of aqueous films between bubbles. Part 1. The effect of speed on bubble coalescence in purified water and simple electrolyte solutions

Film thinning experiments have been conducted with aqueous films between two air phases in a thin film pressure balance. The films are free of added surfactant but simple NaCl electrolyte is added in some experiments. Initially the experiments begin with a comparatively large volume of water in a cylindrical capillary tube a few millimeters in diameter, and by withdrawing water from the center of the tube the two bounding menisci are drawn together at a prescribed rate. Thismodels two air bubbles approaching at a controlled speed. In pure water, the results show three regimes of behavior depending on the approach speed; at slow speed (<1 μm/s) it is possible to form a flat film of pure water, ∼100 nm thick, that is stabilized indefinitely by disjoining pressure due to repulsive double-layer interactions between naturally charged air/water interfaces. The data are consistent with a surface potential of -57mV on the bubble surfaces. At intermediate approach speed (∼1-150 μm/s), the films are transiently stable due to hydrodynamic drainage effects, and bubble coalescence is delayed by ∼10-100 s. At approach speeds greater than ∼150 μm/s, the hydrodynamic resistance appears to become negligible, and the bubbles coalesce without any measurable delay. Explanations for these observations are presented that take into account Derjaguin-Landau-Verwey-Overbeek and Marangoni effects entering through disjoining pressure, surface mobility, and hydrodynamic flow regimes in thin film drainage. In particular, it is argued that the dramatic reduction in hydrodynamic resistance is a transition from viscosity-controlled drainage to inertia-controlled drainage associated with a change from immobile to mobile air/water interfaces on increasing the speed of approach of two bubbles. A simple model is developed that accounts for the boundaries between different film stability or coalescence regimes. Predictions of the model are consistent with the data, and the effects of adding electrolyte can be explained. In particular, addition of electrolyte at high concentration inhibits the near-instantaneous coalescence phenomenon, thereby contributing to increased foam film stability at high approach speeds, as reported in previous literature. This work highlights the significance of bubble approach speed as well as electrolyte concentration in affecting bubble coalescence.

Dose-dependent effect of Resveratrol on bladder cancer cells: Chemoprevention and oxidative stress

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

Effect of gender on training-induced vascular remodeling in SHR

There is accumulating evidence that physical inactivity, associated with the modern sedentary lifestyle, is a major determinant of hypertension. It represents the most important modifiable risk factor for cardiovascular diseases, which are the leading cause of morbidity and mortality for both men and women. In addition to involving sympathetic overactivity that alters hemodynamic parameters, hypertension is accompanied by several abnormalities in the skeletal muscle circulation including vessel rarefaction and increased arteriole wall-to-lumen ratio, which contribute to increased total peripheral resistance. Low-intensity aerobic training is a promising tool for the prevention, treatment and control of high blood pressure, but its efficacy may differ between men and women and between male and female animals. This review focuses on peripheral training-induced adaptations that contribute to a blood pressure-lowering effect, with special attention to differential responses in male and female spontaneously hypertensive rats (SHR). Heart, diaphragm and skeletal muscle arterioles (but not kidney arterioles) undergo eutrophic outward remodeling in trained male SHR, which contributed to a reduction of peripheral resistance and to a pressure fall. In contrast, trained female SHR showed no change in arteriole wall-to-lumen ratio and no pressure fall. on the other hand, training-induced adaptive changes in capillaries and venules (increased density) were similar in male and female SHR, supporting a similar hyperemic response to exercise.

A study of the effect of hemorrhage on the cardiorespiratory actions of halothane, isoflurane and sevoflurane in the dog

Objective To compare the cardiorespiratory changes induced by equipotent concentrations of halothane (HAL), isoflurane (ISO) and sevollurane (SEVO) before and after hemorrhage.Study design. Prospective, randomized clinical trial.Animals. Twenty-four healthy adult dogs weighing 15.4 +/- 3.4 kg (mean +/- SD).Methods. Animals were randomly allocated to one of three groups (n = 8 per group). In each group, anesthesia was maintained with 1.5 minimum alveolar concentration of HAL (1.3%), ISO (1.9%,) and SEVO (3.5%) in oxygen. Controlled ventilation was performed to maintain eucapnia. Cardiorespiratory variables were evaluated at baseline (between 60 and 90 minutes after induction), immediately after and 30 minutes after the withdrawal of 32 mL kg(-1) of blood (400% of the estimated blood volume) over a 30-minute period.Results. During baseline conditions, ISO and SEVO resulted in higher cardiac index (CI) than HAL. Heart rates were higher with SEVO at baseline. while mean arterial pressure (MAP) and mean pulmonary arterial pressure did not differ between groups. Although heart rate values were higher for ISO and SEVO after hemorrhage, only ISO resulted in a higher CI when compared with HAL. In ISO-anesthetized dogs, MAP was higher immediately after hemorrhage, and this was related to better maintenance of CI and to an increase in systemic vascular resistance index from baseline.Conclusions. Although the hemodynamic responses of ISO and SEVO are similar in normovolaemic dogs, ISO results in better maintenance of circulatory function during the early period following a massive blood loss. Clinical relevance Inhaled anesthetics should be used judiciously in animals presented with blood loss. However, if an inhalational agent is to be used under these circumstances, ISO may provide better hemodynamic stability than SEVO or HAL.

Effect of felodipine on myocardial and renal injury induced by aldosterone-high salt hypertension in uninephrectomized rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of lidocaine on the minimum alveolar concentration of sevoflurane in dogs

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

The effect of temperature on self-etching adhesive penetration.

The purpose of this study was to investigate the penetration of an aggressive self-etching adhesive system at refrigerated and room temperatures into ground and unground enamel surfaces. Thirty extracted human teeth were used to measure adhesive penetration into enamel by light microscopy analysis (x400). The unground enamel surfaces were cleaned with pumice and water using a rotary dental brush. For each specimen, part of the unground enamel was manually ground and part was kept intact. A self-etch adhesive was evaluated for its ability to penetrate ground and unground enamel surfaces at room temperature (25 degrees C), at 30 minutes after removal from the refrigerator, and immediately after removal from the refrigerator (6 degrees C). Data were analyzed using variance and the Tukey test, which revealed significant differences in length of penetration of this material when applied on ground and unground enamel surfaces and between the different temperatures used (P > .05). The self-etching system used in this study had significantly lower penetration into unground enamel and at 6 degrees C (P < .05). No statistical difference was found between the interactions of these factors. It was concluded that the self-etching system produced the best penetration into ground enamel surface at room temperature (25 degrees C) and at 30 minutes after removing the specimens from the refrigerator.

Effect of exercise on the maternal outcome in pregnancy of spontaneously hypertensive rats

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

Dose-dependent effect of Resveratrol on bladder cancer cells: Chemoprevention and oxidative stress

Background: Over 6 million people die annually in the world because of cancer. Several groups are focused on studying cancer chemoprevention approaches. Resveratrol, a polyphenol, at high dosages, has been reported as antitumor and chemopreventive. However, it has a dose-dependent effect on cell death, even on some cancer cells. Objectives: Our aim was to investigate this dose-dependent effect on human bladder carcinoma ECV304 cells during oxidative stress condition. Methods: For this purpose. ECV304 cells incubated with different Resveratrol concentrations were analyzed as for their metabolic rate, membrane permeability, DNA fragmentation, anti/proapoptotic protein levels and phosphatidylserine exposure after oxidative stress. Results: Resveratrol induced cell death at high concentrations (>20 mu M), but not at low ones (0.1-20 mu M). Pretreatment with 2.5 mu M protected the cells from oxidative damage, whereas 50 mu M intensified the cell death and significantly increased Bad/Bcl-2 ratio (proapoptotic/antiapoptotic proteins). Resveratrol was able to modulate NO and PGE(2) secretion and performed an anti-adhesion activity of neutrophils on PMA-activated ECV304 cells. Conclusions: Resveratrol at high doses induces cell death of ECV304 cells whereas low doses induce protection. Modulation of Bcl-2 protein induced by Resveratrol could be mediating this effect. This information about the role of Resveratrol on cancer alerts us about its dose-dependent effects and could lead the design of future chemoprevention strategies. Published by Elsevier Ireland Ltd.

The peripheral L-arginine-nitric oxide-cyclic GMP pathway and ATP-sensitive K+ channels are involved in the antinociceptive effect of crotalphine on neuropathic pain in rats

Crotalphine, a 14 amino acid peptide first isolated from the venom of the South American rattlesnake Crotalus durissus terrificus, induces a peripheral long-lasting and opioid receptor-mediated antinociceptive effect in a rat model of neuropathic pain induced by chronic constriction of the sciatic nerve. In the present study, we further characterized the molecular mechanisms involved in this effect, determining the type of opioid receptor responsible for this effect and the involvement of the nitric oxide-cyclic GMP pathway and of K+ channels. Crotalphine (0.2 or 5 mu g/kg, orally; 0.0006 mu g/paw), administered on day 14 after nerve constriction, inhibited mechanical hyperalgesia and low-threshold mechanical allodynia. The effect of the peptide was antagonized by intraplantar administration of naltrindole, an antagonist of delta-opioid receptors, and partially reversed by norbinaltorphimine, an antagonist of kappa-opioid receptors. The effect of crotalphine was also blocked by 7-nitroindazole, an inhibitor of the neuronal nitric oxide synthase; by 1H-(1,2,4) oxadiazolo[4,3-a]quinoxaline-1-one, an inhibitor of guanylate cyclase activation; and by glibenclamide, an ATP-sensitive K+ channel blocker. The results suggest that peripheral delta-opioid and kappa-opioid receptors, the nitric oxide-cyclic GMP pathway, and ATP-sensitive K+ channels are involved in the antinociceptive effect of crotalphine. The present data point to the therapeutic potential of this peptide for the treatment of chronic neuropathic pain. Behavioural Pharmacology 23:14-24 (C) 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.