A Thermoresponsive injectable drug delivery system of chitosan/ß-glycerophosphate with gellan gum/alginate microparticles.

The development of new Drug Delivery Systems (DDS) by incorporating microparticles within hydrogels can prolong the release rate of drugs and/or other bioactive agents. In this study, we combined gellan gum/alginate microparticles within a thermoresponsive chitosan (Ch) hydrogel with ß-Glycerophosphate (ß-GP), designing the system to be in the sol state at 21 °C and in the gel state at 37 °C to enable the injectability of the system. The system was in the sol state between 10 °C and 21 °C. Higher concentrations of ß-GP (0, 2, 3, 4, 5 w/v%) and microparticles (0, 2 and 5 w/v%) allowed a faster sol-gel transition with higher mechanical strength at 37 °C. However, the sol-gel transition was not instantaneous. The release profile of methylene blue (MB) from the microparticles was significantly affected by their incorporation in Ch/ß-GP hydrogels, only allowing the release of 60-70 % of MB for 6 days, while the microparticles alone released all the MB in 48 h. The proposed system did not present cytotoxicity to VERO cell lines as a preliminary assay, with the Ch/ß-GP/GG:Alg having >90 % of cellular viability. The proposed Ch/ß-GP system proved to have a delaying effect on drug release and biocompatible properties, being a promising future DDS.

Injectable Hydrogels Based on Pluronic/Water Systems Filled with Alginate Microparticles for Biomedical Applications.

A (model) composite system for drug delivery was developed based on a thermoresponsive hydrogel loaded with microparticles. We used Pluronic F127 hydrogel as the continuous phase and alginate microparticles as the dispersed phase of this composite system. It is well known that Pluronic F127 forms a gel when added to water in an appropriate concentration and in a certain temperature range. Pluronic F127 hydrogel may be loaded with drug and injected, in its sol state, to act as a drug delivery system in physiological environment. A rheological characterization allowed the most appropriate concentration of Pluronic F127 (15.5 wt%) and appropriate alginate microparticles contents (5 and 10 wt%) to be determined. Methylene blue (MB) was used as model drug to perform drug release studies in MB loaded Pluronic hydrogel and in MB loaded alginate microparticles/Pluronic hydrogel composite system. The latter showed a significantly slower MB release than the former (10 times), suggesting its potential in the development of dual cargo release systems either for drug delivery or tissue engineering.

Fetal primary hydrothorax with spontaneous resolution.

Fetal primary hydrothorax is a rare congenital anomaly with an estimated incidence of 1:10.000-15.000 pregnancies, with an unpredictable clinical course, ranging from spontaneous resolution to fetal death. We present a case of a unilateral fetal pleural effusion identified at 35th gestational week. A 37 year-old woman (G2P1) presented to our routine term pregnancy evaluation. The pregnancy had been otherwise uneventful. At ecographic evaluation a large anechogenic fluid collection was identified in the right fetal hemithorax, with atelectasis of right lung, displacing the heart and mediastinal structures to the contralateral hemithorax. Hydramnios was also identified. No other structural abnormalities were detected, as no signs of hydrops. Fetal biometry was compatible with gestational age. Fetal ecochardiogram was structurally and functionally normal. Doppler evaluation of the peak systolic velocity in the middle cerebral artery was normal. Screening for congenital infections was negative. Complete blood cell count, blood type and antibody screening rulled-out immune hydrops. Karyotype analysis was not performed as family decision. Serial ecographic re-evaluations showed a progressive volume decrease and at the 38th week there was total resolution of the effusion. A C-section was performed at the 39th week. A live female infant was born weighing 3205 g, with no need of ventilatory support. One year post-partum follow-up evaluation confirmed the child was healthy. Spontaneous regression has been reported to occur in 9-22% of primary fetal hydrothoraxes, but the features predicting a better prognosis remain difficult to define. Unilateral effusion, spontaneous resolution and absence of hydrops at the age of diagnosis seem to be indicators of better outcome.

A novel effective method for the assessment of microvascular function in male patients with coronary artery disease: a pilot study using laser speckle contrast imaging.

Evaluation of microvascular endothelial function is essential for investigating the pathophysiology and treatment of cardiovascular and metabolic diseases. Although laser speckle contrast imaging technology is well accepted as a noninvasive methodology for assessing microvascular endothelial function, it has never been used to compare male patients with coronary artery disease with male age-matched healthy controls. Thus, the aim of this study was to determine whether laser speckle contrast imaging could be used to detect differences in the systemic microvascular functions of patients with established cardiovascular disease (n=61) and healthy age-matched subjects (n=24). Cutaneous blood flow was assessed in the skin of the forearm using laser speckle contrast imaging coupled with the transdermal iontophoretic delivery of acetylcholine and post-occlusive reactive hyperemia. The maximum increase in skin blood flow induced by acetylcholine was significantly reduced in the cardiovascular disease patients compared with the control subjects (74 vs 116%; P<0.01). With regard to post-occlusive reactive hyperemia-induced vasodilation, the patients also presented reduced responses compared to the controls (0.42±0.15 vs 0.50±0.13 APU/mmHg; P=0.04). In conclusion, laser speckle contrast imaging can identify endothelial and microvascular dysfunctions in male individuals with cardiovascular disease. Thus, this technology appears to be an efficient non-invasive technique for evaluating systemic microvascular and endothelial functions, which could be valuable as a peripheral marker of atherothrombotic diseases in men.

Oxygen uptake, respiratory exchange ratio, or total distance: a comparison of methods to equalize exercise volume in Wistar rats.

This study compared strategies to equalize the volume of aerobic exercise performed with different intensities by Wistar rats, based on the distance covered during exercise bouts and energy expenditure (EE, isocaloric sessions) obtained from oxygen uptake (V̇O2) or respiratory exchange ratio (RER). Thirty-three male rats (270.5±12.8 g) underwent maximal exercise tests to determine V̇O2 reserve (V̇O2R), being randomly assigned to three groups: moderate-intensity continuous exercise at speed corresponding to 50% V̇O2R (MIC; n=11); high-intensity continuous exercise at 80% V̇O2R (HIC; n=11); and high-intensity intermittent exercise (HII; n=11) at 60% V̇O2R (3 min) and 80% V̇O2R (4 min). Exercise duration was calculated individually to elicit EE of 5 kcal in each session. No difference between groups was found for total running distance (MIC: 801±46, HIC: 734±42, HII: 885±64 m; P=0.13). Total EE measured by RER was systematically underestimated compared to values obtained from V̇O2 (HII: 4.5% and MIC: 6.2%, P<0.05). Total EE (calculated from V̇O2), and duration of HIC bouts (2.8 kcal and 30.8±2.2 min) were lower (P<0.0001) than in MIC (4.9 kcal and 64.7±1.8 min) and HII (4.7 kcal and 46.9±2.2 min). Predicted and actual values of total V̇O2, total EE, and duration of isocaloric sessions were similar in MIC and HII (P>0.05), which were both higher than in HIC (P<0.0001). In conclusion, the time to achieve a given EE in exercise bouts with different intensities did not correspond to the total distance. Therefore, the volume of aerobic exercise in protocols involving Wistar rats should be equalized using EE rather than total covered distance.

Oxygen uptake, respiratory exchange ratio, or total distance: a comparison of methods to equalize exercise volume in Wistar rats

This study compared strategies to equalize the volume of aerobic exercise performed with different intensities by Wistar rats, based on the distance covered during exercise bouts and energy expenditure (EE, isocaloric sessions) obtained from oxygen uptake (V̇O2) or respiratory exchange ratio (RER). Thirty-three male rats (270.5±12.8 g) underwent maximal exercise tests to determine V̇O2 reserve (V̇O2R), being randomly assigned to three groups: moderate-intensity continuous exercise at speed corresponding to 50% V̇O2R (MIC; n=11); high-intensity continuous exercise at 80% V̇O2R (HIC; n=11); and high-intensity intermittent exercise (HII; n=11) at 60% V̇O2R (3 min) and 80% V̇O2R (4 min). Exercise duration was calculated individually to elicit EE of 5 kcal in each session. No difference between groups was found for total running distance (MIC: 801±46, HIC: 734±42, HII: 885±64 m; P=0.13). Total EE measured by RER was systematically underestimated compared to values obtained from V̇O2 (HII: 4.5% and MIC: 6.2%, P<0.05). Total EE (calculated from V̇O2), and duration of HIC bouts (2.8 kcal and 30.8±2.2 min) were lower (P<0.0001) than in MIC (4.9 kcal and 64.7±1.8 min) and HII (4.7 kcal and 46.9±2.2 min). Predicted and actual values of total V̇O2, total EE, and duration of isocaloric sessions were similar in MIC and HII (P>0.05), which were both higher than in HIC (P<0.0001). In conclusion, the time to achieve a given EE in exercise bouts with different intensities did not correspond to the total distance. Therefore, the volume of aerobic exercise in protocols involving Wistar rats should be equalized using EE rather than total covered distance.

Restrictive guideline reduces platelet count thresholds for transfusions in very low birth weight preterm infants.

BACKGROUND AND OBJECTIVES: Platelet transfusions are performed almost entirely according to expert experience. This study assessed the effectiveness of a restrictive guideline to reduce platelet transfusions in preterm infants. METHODS: A retrospective cohort of preterm infants with a birth weight of <1500 g had been born in 2 periods. In Period 1, a transfusion was indicated for a platelet count of <50,000/ml in clinically stable neonates or <100,000/ml in bleeding or clinically unstable infants. In Period 2, the indications were restricted to <25,000/ml in clinically stable neonates, or <50,000/ml in newborns who were either on mechanical ventilation, subject to imminent invasive procedures, within 72 h following a seizure, or extremely premature and <7 days old. A count of <100,000/ml was indicated for bleeding or major surgery. RESULTS: Periods 1 and 2 comprised 121 and 134 neonates, respectively. The rates of ventricular haemorrhage and intrahospital death were similar in both periods. The percentage of transfused infants, the odds of receiving a platelet transfusion, the mean platelet count before transfusion and the percentage of transfusions with a platelet count >50,000/ml were greater in Period 1. Among thrombocytopenic neonates, the percentage of transfused neonates and the number of transfusions were similar in both groups. CONCLUSION: The restrictive guideline for platelet transfusions reduced the platelet count thresholds for neonatal transfusions without increasing the rate of ventricular haemorrhage.

Doxorubicin vs. ladirubicin: methods for improving osteosarcoma treatment.

Osteosarcoma is the most common primary bone tumor in children and adolescents, with a 5-year disease free survival rate of 70%. Current chemotherapy regimens comprise a group of chemotherapeutic agents in which doxorubicin is included. However, tumor resistance to anthracyclines and cardiotoxicity are limiting factors for its usage. Liposomal formulations of doxorubicin improve its anti-cancer effects but are still insufficient. The research in this area has lead to the production of anthracyclines analogues, such as ladirubicin, the leading compound of alkylcyclines. This new anticancer agent has shown promising results in vivo and in vitro, being effective against osteosarcoma cell lines, including those with a multidrug resistant phenotype. In phase I clinical trials, this molecule caused mild side effects and did not induce significant cardiotoxicity at doses ranging from 1 to 16 mg/m(2), resulting in a peak plasma concentration (C(max)) ranging from 0.5 to 1.5 µM. The recommended doses for phase II studies were 12 and 14 mg/m(2) in heavily and minimally pretreated/non-pretreated patients, respectively. Phase II clinical trials in ovary, breast, colorectal cancer, NSCLC and malignant melanoma are underway. Given the improved molecular targeting efficacy of these new compounds, ongoing approaches have sought to improve drug delivery systems, to improve treatment efficacy while reducing systemic toxicity. The combination of these two approaches may be a good start for the discovery of new treatment for osteosarcoma.

Thin and flexible bio-batteries made of electrospun cellulose-based membranes.

The present work proposes the development of a bio-battery composed by an ultrathin monolithic structure of an electrospun cellulose acetate membrane, over which was deposited metallic thin film electrodes by thermal evaporation on both surfaces. The electrochemical characterization of the bio-batteries was performed under simulated body fluids like sweat and blood plasma [salt solution--0.9% (w/w) NaCl]. Reversible electrochemical reactions were detected through the cellulose acetate structure. Thus, a stable electrochemical behavior was achieved for a bio-battery with silver and aluminum thin films as electrodes. This device exhibits the ability to supply a power density higher than 3 µW cm(-2). Finally, a bio-battery prototype was tested on a sweated skin, demonstrating the potential of applicability of this bio-device as a micropower source.

Effects of a supervised exercise program on the physical fitness and immunological function of HIV-infected patients.

AIM: Exercise effects in subjects with HIV/AIDS are not entirely understood. The study aimed to investigate the effects of a supervised exercise program on the physical fitness and immunological function of HIV-infected subjects. METHODS: Twenty-seven highly active antiretroviral therapy treated HIV-infected patients (age: 45±2 years; CD4-T: 21.3±2.2%) were assigned to a control (CG, n=8) or experimental (EG, n=19) group. The EG participated in a 12-week exercise program, consisting of aerobic training, strength, and flexibility exercises (3 times/wk; aerobic-30min: PWC 150; strength-50min: 3 sets of 12 reps of 5 exercises at 60-80% 12 RM; flexibility-10min: 2 sets of 30 s at maximal range of motion of 8 exercises). RESULTS: Prior to training there was no significant difference in any variable between the EG and the CG. Flexibility (23%, P<0.05), 12 repetition maximum in the leg press and seated bilateral row exercises (54% and 65% respectively, P<0.05) increased, while the heart rate at a given cycle ergometer workload declined (19% for slope and 12% for intercept, P<0.05) in the EG, but not in the CG. No significant differences were found for the relative and absolute CD4 T-cell counts between groups prior to or after training, but there was a slight enhancement trend in the EG (16%, P=0.19). CONCLUSION: Overall training can improve the muscle and aerobic fitness of HIV-infected patients with no negative effect on their immunological function.

A systematic study of solution and processing parameters on nanofiber morphology using a new electrospinning apparatus.

We assembled a new electrospinning apparatus and used poly(ethylene oxide) as a model polymer to perform a systematic study on the influence of solution and processing parameters on the morphology of electrospun nanofibers. Solution parameters studied were polymer concentration and molecular mass. The solvent used, 60 wt% water, 40 wt% ethanol, was the same throughout the study. Processing parameters analyzed were: solution feed rate, needle tip-collector distance and electrostatic potential difference between the needle and collector. Solution viscosity increased both with polymer concentration and molecular mass. Polymer concentration plays a decisive role on the outcome of the electrospinning process: a low concentration led to the formation of beaded fibers; an intermediate concentration yielded good quality fibers; a high concentration resulted in a bimodal size distribution and at even higher concentration a distributed deposition. Fiber diameter increased with polymer molecular mass and higher molecular masses are associated with a higher frequency of splaying events. Fiber diameter increased linearly with solution feed rate. While an increase in needle-collector distance represents a weaker electric field, a greater distance to be covered by the fibers and a longer flight time, presumably favoring the formation of thinner fibers, as solvent evaporation leads to a local increase of concentration and viscosity, viscoelastic forces opposing stretching caused an increase of fiber diameter with needle-collector distance. A higher voltage applied at the needle is associated with a higher charging of the polymer and a higher electrical current through it ultimately leading to incomplete solvent evaporation and merged fibers being produced. Controlling the charging of the polymer independently of the electric field strength was achieved by applying a voltage to the collector while distance and potential difference were kept constant. The increased electrostatic repulsion associated with an increase of the high voltage applied to the needle led to the disappearance of merged fibers.

Complementary regulation of four Eucalyptus CBF genes under various cold conditions.

CBF transcription factors play central roles in the control of freezing tolerance in plants. The isolation of two additional CBF genes, EguCBF1c and EguCBF1d, from E. gunnii, one of the cold-hardiest Eucalyptus species, is described. While the EguCBF1D protein sequence is very similar to the previously characterized EguCBF1A and EguCBF1B sequences, EguCBF1C is more distinctive, in particular in the AP2-DBD (AP2-DNA binding domain). The expression analysis of the four genes by RT-qPCR reveals that none of them is specific to one stress but they are all preferentially induced by cold, except for the EguCBF1c gene which is more responsive to salt. The calculation of the transcript copy number enables the quantification of constitutive CBF gene expression. This basal level, significant for the four genes, greatly influences the final EguCBF1 transcript level in the cold. A cold shock at 4 degrees C, as well as a progressive freezing which mimics a natural frost episode, trigger a fast and strong response of the EguCBF1 genes, while growth at acclimating temperatures results in a lower but more durable induction. The differential expression of the four EguCBF1 genes under these cold regimes suggests that there is a complementary regulation. The high accumulation of the CBF transcript, observed in response to the different types of cold conditions, might be a key for the winter survival of this evergreen broad-leaved tree.

The lipid transfer proteins (LTP) essentially concentrate in the skin of Rosaceae fruits as cell surface exposed allergens.

The localization and distribution of non-specific lipid transfer proteins (nsLTP) allergens in the skin and pulp of Rosaceae fruits (apple, peach, apricot, plum) has been investigated. nsLTP essentially concentrate in the pericarp of the fruits whereas the pulp contains lower amounts of allergens. Immunolocalization showed they are primarily located in the cytosol but are subsequently excreted and finally accumulate at the plasmalemma-cell wall interface and in the cell wall. However, high discrepancies were observed in the content of allergens among, e.g. different cultivars of apple. As a consequence, the consumption of peeled-off fruits is recommended to reduce the risk of severe allergic reactions (anaphylactic shock) in individuals sensitized to Rosaceae fruits.

Estudo morfometrico do musculo soleo denervado de ratos tratados pela associacao de metformina e estimulacao eletrica / Morphometric study os rats denervated soleus muscle treated by association of metformin and electrostimulation

Diversos estudos relatam os efeitos da denervacao sobre a homeostasia energetica do musculo soleo, sendo demonstrado que concomitante ao processo de atrofia ha reducao no metabolismo muscular da glicose e aumento de colageno no endomisio e perimisio, indicando que a atrofia e acompanhada de alteracoes metabolicas e fibrose. O objetivo deste trabalho foi estudar os efeitos da associacao dos tratamentos com metformina(0,1g/kg) e estimulacao eletrica (f=10Hz, fase=3ms, 20 min/dia) sobre a morfologia e reserva de glicogenio do musculo soleo denervado de ratos. Tratamento com PAS (acido periodico de Schift) foi utilizado para evidenciar reservas de glicogenio, e a densidade de areas das fibras foi obtida pela tecnica morfometrica e analisada pela ANOVA com teste F e teste de Tukey para comparacao das medias. Apos 15 dias, a associacao dos tratemntos nao recuperou o peso do musculo soleo (69,33mg), perdido com a denervacao (63,33mg, p>0,05), no entanto, promoveu aumento de granulos de glicogenio, evidenciando melhora nas condicoes metabolicas das fibras