Immune Regulatory Properties of Allogeneic Adipose-Derived Mesenchymal Stem Cells in the Treatment of Experimental Autoimmune Diabetes

Adipose-derived mesenchymal stem cells (ADMSCs) display immunosuppressive properties, suggesting a promising therapeutic application in several autoimmune diseases, but their role in type 1 diabetes (T1D) remains largely unexplored. The aim of this study was to investigate the immune regulatory properties of allogeneic ADMSC therapy in T cell-mediated autoimmune diabetes in NOD mice. ADMSC treatment reversed the hyperglycemia of early-onset diabetes in 78% of diabetic NOD mice, and this effect was associated with higher serum insulin, amylin, and glucagon-like peptide 1 levels compared with untreated controls. This improved outcome was associated with downregulation of the CD4(+) Th1-biased immune response and expansion of regulatory T cells (Tregs) in the pancreatic lymph nodes. Within the pancreas, inflammatory cell infiltration and interferon-gamma levels were reduced, while insulin, pancreatic duodenal homeobox-1, and active transforming growth factor-beta 1 expression were increased. In vitro, ADMSCs induced the expansion/proliferation of Tregs in a cell contact-dependent manner mediated by programmed death ligand 1. In summary, ADMSC therapy efficiently ameliorates autoimmune diabetes pathogenesis in diabetic NOD mice by attenuating the Th1 immune response concomitant with the expansion/proliferation of Tregs, thereby contributing to the maintenance of functional beta-cells. Thus, this study may provide a new perspective for the development of ADMSC-based cellular therapies for T1D. Diabetes 61:2534-2545, 2012

Parametric Analysis of Effective Material Properties of Thickness-Shear Piezoelectric Macro-Fibre Composites

A previous study on the characterization of effective material properties of a d(15) thickness-shear piezoelectric Macro-Fibre Composite (MFC) made of seven layers (Kapton, Acrylic, Electrode, Piezoceramic Fibre and Epoxy Composite, Electrode, Acrylic, Kapton) using a finite element homogenization method has shown that the packaging reduces significantly the shear stiffness of the piezoceramic material and, thus, leads to significantly smaller effective electromechanical coupling coefficient k(15) and piezoelectric stress constant e(15) when compared to the piezoceramic fibre properties. Therefore, the main objective of this work is to perform a parametric analysis in which the effect of the variations of fibre volume fraction, Epoxy elastic modulus, electrode thickness and active layer thickness on the MFC effective material properties is evaluated. Results indicate that an effective d(15) MFC should use relatively thick fibres having relatively high shear modulus and relatively stiff epoxy filler. On the other hand, the electrode thickness does not affect significantly the MFC performance.

Pilot survey of expressed sequence tags (ESTs) from the asexual blood stages of Plasmodium vivax in human patients

Abstract Background Plasmodium vivax is the most widely distributed human malaria, responsible for 70–80 million clinical cases each year and large socio-economical burdens for countries such as Brazil where it is the most prevalent species. Unfortunately, due to the impossibility of growing this parasite in continuous in vitro culture, research on P. vivax remains largely neglected. Methods A pilot survey of expressed sequence tags (ESTs) from the asexual blood stages of P. vivax was performed. To do so, 1,184 clones from a cDNA library constructed with parasites obtained from 10 different human patients in the Brazilian Amazon were sequenced. Sequences were automatedly processed to remove contaminants and low quality reads. A total of 806 sequences with an average length of 586 bp met such criteria and their clustering revealed 666 distinct events. The consensus sequence of each cluster and the unique sequences of the singlets were used in similarity searches against different databases that included P. vivax, Plasmodium falciparum, Plasmodium yoelii, Plasmodium knowlesi, Apicomplexa and the GenBank non-redundant database. An E-value of <10-30 was used to define a significant database match. ESTs were manually assigned a gene ontology (GO) terminology Results A total of 769 ESTs could be assigned a putative identity based upon sequence similarity to known proteins in GenBank. Moreover, 292 ESTs were annotated and a GO terminology was assigned to 164 of them. Conclusion These are the first ESTs reported for P. vivax and, as such, they represent a valuable resource to assist in the annotation of the P. vivax genome currently being sequenced. Moreover, since the GC-content of the P. vivax genome is strikingly different from that of P. falciparum, these ESTs will help in the validation of gene predictions for P. vivax and to create a gene index of this malaria parasite.

Mechanisms underlying skeletal muscle insulin resistance induced by fatty acids: importance of the mitochondrial function

Insulin resistance condition is associated to the development of several syndromes, such as obesity, type 2 diabetes mellitus and metabolic syndrome. Although the factors linking insulin resistance to these syndromes are not precisely defined yet, evidence suggests that the elevated plasma free fatty acid (FFA) level plays an important role in the development of skeletal muscle insulin resistance. Accordantly, in vivo and in vitro exposure of skeletal muscle and myocytes to physiological concentrations of saturated fatty acids is associated with insulin resistance condition. Several mechanisms have been postulated to account for fatty acids-induced muscle insulin resistance, including Randle cycle, oxidative stress, inflammation and mitochondrial dysfunction. Here we reviewed experimental evidence supporting the involvement of each of these propositions in the development of skeletal muscle insulin resistance induced by saturated fatty acids and propose an integrative model placing mitochondrial dysfunction as an important and common factor to the other mechanisms.

Biphasic positive airway pressure minimizes biological impact on lung tissue in mild acute lung injury independent of etiology

Abstract Introduction Biphasic positive airway pressure (BIVENT) is a partial support mode that employs pressure-controlled, time-cycled ventilation set at two levels of continuous positive airway pressure with unrestricted spontaneous breathing. BIVENT can modulate inspiratory effort by modifying the frequency of controlled breaths. Nevertheless, the optimal amount of inspiratory effort to improve respiratory function while minimizing ventilator-associated lung injury during partial ventilatory assistance has not been determined. Furthermore, it is unclear whether the effects of partial ventilatory support depend on acute lung injury (ALI) etiology. This study aimed to investigate the impact of spontaneous and time-cycled control breaths during BIVENT on the lung and diaphragm in experimental pulmonary (p) and extrapulmonary (exp) ALI. Methods This was a prospective, randomized, controlled experimental study of 60 adult male Wistar rats. Mild ALI was induced by Escherichia coli lipopolysaccharide either intratracheally (ALIp) or intraperitoneally (ALIexp). After 24 hours, animals were anesthetized and further randomized as follows: (1) pressure-controlled ventilation (PCV) with tidal volume (Vt) = 6 ml/kg, respiratory rate = 100 breaths/min, PEEP = 5 cmH2O, and inspiratory-to-expiratory ratio (I:E) = 1:2; or (2) BIVENT with three spontaneous and time-cycled control breath modes (100, 75, and 50 breaths/min). BIVENT was set with two levels of CPAP (Phigh = 10 cmH2O and Plow = 5 cmH2O). Inspiratory time was kept constant (Thigh = 0.3 s). Results BIVENT was associated with reduced markers of inflammation, apoptosis, fibrogenesis, and epithelial and endothelial cell damage in lung tissue in both ALI models when compared to PCV. The inspiratory effort during spontaneous breaths increased during BIVENT-50 in both ALI models. In ALIp, alveolar collapse was higher in BIVENT-100 than PCV, but decreased during BIVENT-50, and diaphragmatic injury was lower during BIVENT-50 compared to PCV and BIVENT-100. In ALIexp, alveolar collapse during BIVENT-100 and BIVENT-75 was comparable to PCV, while decreasing with BIVENT-50, and diaphragmatic injury increased during BIVENT-50. Conclusions In mild ALI, BIVENT had a lower biological impact on lung tissue compared to PCV. In contrast, the response of atelectasis and diaphragmatic injury to BIVENT differed according to the rate of spontaneous/controlled breaths and ALI etiology.

The effect of bone allografts combined with bone marrow stromal cells on the healing of segmental bone defects in a sheep model

Background: The repair of large bone defects is a major orthopedic challenge because autologous bone grafts are not available in large amounts and because harvesting is often associated with donor-site morbidity. Considering that bone marrow stromal cells (BMSC) are responsible for the maintenance of bone turnover throughout life, we investigated bone repair at a site of a critically sized segmental defect in sheep tibia treated with BMSCs loaded onto allografts. The defect was created in the mid-portion of the tibial diaphysis of eight adult sheep, and the sheep were treated with ex-vivo expanded autologous BMSCs isolated from marrow aspirates and loaded onto cortical allografts (n = 4). The treated sheep were compared with control sheep that had been treated with cell-free allografts (n = 4) obtained from donors of the same breed as the receptor sheep. Results: The healing response was monitored by radiographs monthly and by computed tomography and histology at six, ten, fourteen, and eighteen weeks after surgery. For the cell-loaded allografts, union was established more rapidly at the interface between the host bone and the allograft, and the healing process was more conspicuous. Remodeling of the allograft was complete at 18 weeks in the cell-treated animals. Histologically, the marrow cavity was reestablished, with intertrabecular spaces being filled with adipose marrow and with evidence of focal hematopoiesis. Conclusions: Allografts cellularized with AOCs (allografts of osteoprogenitor cells) can generate great clinical outcomes to noncellularized allografts to consolidate, reshape, structurally and morphologically reconstruct bone and bone marrow in a relatively short period of time. These features make this strategy very attractive for clinical use in orthopedic bioengineering

Molecular origin of charge traps in polyfluorene-based semiconductors

The comprehensive control of morphology and structure is of extreme importance in semiconducting polymers when used as active layers in optoelectronic devices. In the work reported here, a systematic investigation of the structural and dynamical properties of poly(9,9-di-n-octyl-fluorene-alt-benzothiadiazole), known as F8BT, and their correlation with electrical properties is presented when the material is used as an active layer in optoelectronic devices. By means of X-ray diffraction, one observes that in thick layer films (thickness of about 4 μm) grown by drop-cast deposition, a solvent induced crystalline phase exists which evolves to a stable phase as the temperature is raised. This was not observed in thin films (thickness of about 250 nm) prepared by spin-coating within the investigated temperature range. By modeling the current-voltages characteristics of both thick and thin film devices, important information on the influence of crystallization on the trapping states could be drawn. Furthermore, the temperature dependence of the charge carrier mobility was found to be closely related to that of the molecular relaxation processes. The understanding of the nature of such molecular relaxations, measured by solid-state nuclear magnetic resonance methods, allows one to understand the importance of molecular relaxations and microstructure changes on the trap states of the system.

Somatic Mosaic Activating Mutations in PIK3CA Cause CLOVES Syndrome

Congenital lipomatous overgrowth with vascular, epidermal, and skeletal anomalies (CLOVES) is a sporadically occurring, nonhereditary disorder characterized by asymmetric somatic hypertrophy and anomalies in multiple organs. We hypothesized that CLOVES syndrome would be caused by a somatic mutation arising during early embryonic development. Therefore, we employed massively parallel sequencing to search for somatic mosaic mutations in fresh, frozen, or fixed archival tissue from six affected individuals. We identified mutations in PIK3CA in all six individuals, and mutant allele frequencies ranged from 3% to 30% in affected tissue from multiple embryonic lineages. Interestingly, these same mutations have been identified in cancer cells, in which they increase phosphoinositide-3-kinase activity. We conclude that CLOVES is caused by postzygotic activating mutations in PIK3CA. The application of similar sequencing strategies will probably identify additional genetic causes for sporadically occurring, nonheritable malformations.

Li-Fraumeni-like syndrome associated with a large BRCA1 intragenic deletion

Background: Li-Fraumeni (LFS) and Li-Fraumeni-like (LFL) syndromes are associated to germline TP53 mutations, and are characterized by the development of central nervous system tumors, sarcomas, adrenocortical carcinomas, and other early-onset tumors. Due to the high frequency of breast cancer in LFS/LFL families, these syndromes clinically overlap with hereditary breast cancer (HBC). Germline point mutations in BRCA1, BRCA2, and TP53 genes are associated with high risk of breast cancer. Large rearrangements involving these genes are also implicated in the HBC phenotype. Methods: We have screened DNA copy number changes by MLPA on BRCA1, BRCA2, and TP53 genes in 23 breast cancer patients with a clinical diagnosis consistent with LFS/LFL; most of these families also met the clinical criteria for other HBC syndromes. Results: We found no DNA copy number alterations in the BRCA2 and TP53 genes, but we detected in one patient a 36.4 Kb BRCA1 microdeletion, confirmed and further mapped by array-CGH, encompassing exons 9-19. Breakpoints sequencing analysis suggests that this rearrangement was mediated by flanking Alu sequences. Conclusion: This is the first description of a germline intragenic BRCA1 deletion in a breast cancer patient with a family history consistent with both LFL and HBC syndromes. Our results show that large rearrangements in these known cancer predisposition genes occur, but are not a frequent cause of cancer susceptibility.

Three Postpartum Antiretroviral Regimens to Prevent Intrapartum HIV Infection

BACKGROUND The safety and efficacy of adding antiretroviral drugs to standard zidovudine prophylaxis in infants of mothers with human immunodeficiency virus (HIV) infection who did not receive antenatal antiretroviral therapy (ART) because of late identification are unclear. We evaluated three ART regimens in such infants. METHODS Within 48 hours after their birth, we randomly assigned formula-fed infants born to women with a peripartum diagnosis of HIV type 1 (HIV-1) infection to one of three regimens: zidovudine for 6 weeks (zidovudine-alone group), zidovudine for 6 weeks plus three doses of nevirapine during the first 8 days of life (two-drug group), or zidovudine for 6 weeks plus nelfinavir and lamivudine for 2 weeks (three-drug group). The primary outcome was HIV-1 infection at 3 months in infants uninfected at birth. RESULTS A total of 1684 infants were enrolled in the Americas and South Africa (566 in the zidovudine-alone group, 562 in the two-drug group, and 556 in the three-drug group). The overall rate of in utero transmission of HIV-1 on the basis of Kaplan-Meier estimates was 5.7% (93 infants), with no significant differences among the groups. Intrapartum transmission occurred in 24 infants in the zidovudine-alone group (4.8%; 95% confidence interval [CI], 3.2 to 7.1), as compared with 11 infants in the two-drug group (2.2%; 95% CI, 1.2 to 3.9; P=0.046) and 12 in the three-drug group (2.4%; 95% CI, 1.4 to 4.3; P=0.046). The overall transmission rate was 8.5% (140 infants), with an increased rate in the zidovudine-alone group (P=0.03 for the comparisons with the two-and three-drug groups). On multivariate analysis, zidovudine monotherapy, a higher maternal viral load, and maternal use of illegal substances were significantly associated with transmission. The rate of neutropenia was significantly increased in the three-drug group (P < 0.001 for both comparisons with the other groups). CONCLUSIONS In neonates whose mothers did not receive ART during pregnancy, prophylaxis with a two-or three-drug ART regimen is superior to zidovudine alone for the prevention of intrapartum HIV transmission; the two-drug regimen has less toxicity than the three-drug regimen. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development [NICHD] and others; ClinicalTrials.gov number, NCT00099359.)

Rapid sample preparation procedure for As speciation in food samples by LC-ICP-MS

This paper describes a rapid method for arsenic (As) speciation by LC-ICP-MS in several types of food samples. Prior to analysis, samples were milled and the As species extracted from biological tissues by sonication in only 2 min with a solution containing MeOH (10%, v/v) plus HNO3 (2%, v/v). As species were separated by LC using an anion exchange column. Method detection limits for AsB, As3+,DMA, MMA and As5+ were 1.3, 0.9, 0.6, 0.7 and 0.8 ng g(-1), respectively. Method accuracy and precision were traceable to Certified Reference Materials SRM1577 bovine liver from the National Institute of Standards and Technology, CE278 mussel tissue from the Institute of Reference Materials and Measurements and DOLT-3 dogfish liver tissue and DORM-3 fish protein from the National Research Council of Canada. Finally, the method was applied to speciate As in food samples (egg, fish muscle, beef and chicken) purchased in Brazilian markets.

Subcritical fatigue in fuse networks

We obtain the Paris law of fatigue crack propagation in a fuse network model where the accumulated damage in each resistor increases with time as a power law of the local current amplitude. When a resistor reaches its fatigue threshold, it burns irreversibly. Over time, this drives cracks to grow until the system is fractured into two parts. We study the relation between the macroscopic exponent of the crack-growth rate -entering the phenomenological Paris law-and the microscopic damage accumulation exponent, gamma, under the influence of disorder. The way the jumps of the growing crack, Delta a, and the waiting time between successive breaks, Delta t, depend on the type of material, via gamma, are also investigated. We find that the averages of these quantities, <Delta a > and <Delta t >/< t(r)>, scale as power laws of the crack length a, <Delta a > proportional to a(alpha) and <Delta t >/< t(r)> proportional to a(-beta), where < t(r)> is the average rupture time. Strikingly, our results show, for small values of gamma, a decrease in the exponent of the Paris law in comparison with the homogeneous case, leading to an increase in the lifetime of breaking materials. For the particular case of gamma = 0, when fatigue is exclusively ruled by disorder, an analytical treatment confirms the results obtained by simulation. Copyright (C) EPLA, 2012

STOCHASTIC MODEL FOR SIMULATING MAIZE YIELD

Maize is one of the most important crops in the world. The products generated from this crop are largely used in the starch industry, the animal and human nutrition sector, and biomass energy production and refineries. For these reasons, there is much interest in figuring the potential grain yield of maize genotypes in relation to the environment in which they will be grown, as the productivity directly affects agribusiness or farm profitability. Questions like these can be investigated with ecophysiological crop models, which can be organized according to different philosophies and structures. The main objective of this work is to conceptualize a stochastic model for predicting maize grain yield and productivity under different conditions of water supply while considering the uncertainties of daily climate data. Therefore, one focus is to explain the model construction in detail, and the other is to present some results in light of the philosophy adopted. A deterministic model was built as the basis for the stochastic model. The former performed well in terms of the curve shape of the above-ground dry matter over time as well as the grain yield under full and moderate water deficit conditions. Through the use of a triangular distribution for the harvest index and a bivariate normal distribution of the averaged daily solar radiation and air temperature, the stochastic model satisfactorily simulated grain productivity, i.e., it was found that 10,604 kg ha(-1) is the most likely grain productivity, very similar to the productivity simulated by the deterministic model and for the real conditions based on a field experiment.

Neutrophil Paralysis in Plasmodium vivax Malaria

Background: The activation of innate immune responses by Plasmodium vivax results in activation of effector cells and an excessive production of pro-inflammatory cytokines that may culminate in deleterious effects. Here, we examined the activation and function of neutrophils during acute episodes of malaria. Materials and Methods: Blood samples were collected from P. vivax-infected patients at admission (day 0) and 30-45 days after treatment with chloroquine and primaquine. Expression of activation markers and cytokine levels produced by highly purified monocytes and neutrophils were measured by the Cytometric Bead Assay. Phagocytic activity, superoxide production, chemotaxis and the presence of G protein-coupled receptor (GRK2) were also evaluated in neutrophils from malaria patients. Principal Findings: Both monocytes and neutrophils from P. vivax-infected patients were highly activated. While monocytes were found to be the main source of cytokines in response to TLR ligands, neutrophils showed enhanced phagocytic activity and superoxide production. Interestingly, neutrophils from the malaria patients expressed high levels of GRK2, low levels of CXCR2, and displayed impaired chemotaxis towards IL-8 (CXCL8). Conclusion: Activated neutrophils from malaria patients are a poor source of pro-inflammatory cytokines and display reduced chemotactic activity, suggesting a possible mechanism for an enhanced susceptibility to secondary bacterial infection during malaria.

Targeting the non-structural protein 1 from dengue virus to a dendritic cell population confers protective immunity to lethal virus challenge

Dengue is the most prevalent arboviral infection, affecting millions of people every year. Attempts to control such infection are being made, and the development of a vaccine is a World Health Organization priority. Among the proteins being tested as vaccine candidates in preclinical settings is the non-structural protein 1 (NS1). In the present study, we tested the immune responses generated by targeting the NS1 protein to two different dendritic cell populations. Dendritic cells (DCs) are important antigen presenting cells, and targeting proteins to maturing DCs has proved to be an efficient means of immunization. Antigen targeting is accomplished by the use of a monoclonal antibody (mAb) directed against a DC cell surface receptor fused to the protein of interest. We used two mAbs (αDEC205 and αDCIR2) to target two distinct DC populations, expressing either DEC205 or DCIR2 endocytic receptors, respectively, in mice. The fusion mAbs were successfully produced, bound to their respective receptors, and were used to immunize BALB/c mice in the presence of polyriboinosinic: polyribocytidylic acid (poly (I:C)), as a DC maturation stimulus. We observed induction of strong anti-NS1 antibody responses and similar antigen binding affinity irrespectively of the DC population targeted. Nevertheless, the IgG1/IgG2a ratios were different between mouse groups immunized with αDEC-NS1 and αDCIR2-NS1 mAbs. When we tested the induction of cellular immune responses, the number of IFN-γ producing cells was higher in αDEC-NS1 immunized animals. In addition, mice immunized with the αDEC-NS1 mAb were significantly protected from a lethal intracranial challenge with the DENV2 NGC strain when compared to mice immunized with αDCIR2-NS1 mAb. Protection was partially mediated by CD4(+) and CD8(+) T cells as depletion of these populations reduced both survival and morbidity signs. We conclude that targeting the NS1 protein to the DEC205(+) DC population with poly (I:C) opens perspectives for dengue vaccine development.