Protein deficiency attenuates the effects of alloxan on insulin secretion and glucose homeostasis in rats.

We have investigated the effect of alloxan on insulin secretion and glucose homeostasis in rats maintained on a 17% protein (normal protein, NP) or 6% protein (low protein, LP) diet from weaning (21 days old) to adulthood (90 days old). The incidence of alloxan diabetes was higher in the NP (3.5 times) than in the LP group. During an oral glucose tolerance test, the area under serum glucose curve was lower in LP (57%) than in NP rats while there were no differences between the two groups in the area under serum insulin curve. The serum glucose disappearance rate (Kitt) after exogenous insulin administration was higher in LP (50%) than in NP rats. In pancreatic islets isolated from rats not injected with alloxan, acute exposure to alloxan (0.05 mmol/L) reduced the glucose- or arginine-stimulated insulin secretion of NP islets by 78% and 56%, respectively, whereas for islets from LP rats, the reduction was 47% and 17% in the presence of glucose and arginine, respectively. Alloxan treatment reduced the glucose oxidation in islets from LP rats to a lesser extent than in NP islets (23% vs. 56%). In conclusion, alloxan was less effective in producing hyperglycemia in rats fed a low protein diet than in normal diet rats. This effect is attributable to an increased peripheral sensivity to insulin in addition to a better preservation of glucose oxidation and insulin secretion in islets from rats fed a low protein diet.     

Jarid2 regulates mouse epidermal stem cell activation and differentiation

Jarid2 is required for the genomic recruitment of the polycomb repressive complex-2 (PRC2) in embryonic stem cells. However, its specific role during late development and adult tissues remains largely uncharacterized. Here, we show that deletion of Jarid2 in mouse epidermis reduces the proliferation and potentiates the differentiation of postnatal epidermal progenitors, without affecting epidermal development. In neonatal epidermis, Jarid2 deficiency reduces H3K27 trimethylation, a chromatin repressive mark, in epidermal differentiation genes previously shown to be targets of the PRC2. However, in adult epidermis Jarid2 depletion does not affect interfollicular epidermal differentiation but results in delayed hair follicle (HF) cycling as a consequence of decreased proliferation of HF stem cells and their progeny. We conclude that Jarid2 is required for the scheduled proliferation of epidermal stem and progenitor cells necessary to maintain epidermal homeostasis.     

Antigen-based therapies using ignored determinants of beta cell antigens can more effectively inhibit late-stage autoimmune disease in diabetes-prone mice

As organ-specific autoimmune diseases do not become manifest until well-advanced, interventive therapies must inhibit late-stage disease processes. Using a panel of immunogenic peptides from various beta cell Ags, we evaluated the factors influencing the efficacy of Ag-based therapies in diabetes-prone NOD mice with advanced disease. The ability of the major beta cell autoantigen target determinants (TDs) to prime Th2 responses declined sharply between 6 and 12 wk of age, whereas the ability of immunogenic ignored determinants (IDs) of beta cell Ags to prime Th2 responses was unaffected by the disease process. The different patterns of TD and ID immunogenicity (even from the same beta cell Ag) may be due to the exhaustion of uncommitted TD-reactive, but not ID-reactive, T cell pools by recruitment into the autoimmune cascade. Therapeutic efficacy was associated with a peptide's immunogenicity and ability to promote Th2 spreading late in the disease process but not its affinity for I-Ag7 or its expression pattern (beta cell specific/nonspecific or rare/abundant). Characterization of some IDs revealed them to be "absolute" cryptic determinants. Such determinants have little impact on T cell selection, leaving large precursor T cell pools available for priming by synthetic peptides. Traditional Ag-based therapeutics using whole autoantigens or their TDs cannot prime responses to such determinants. These findings suggest a new strategy for designing more efficacious Ag-based therapeutics for late-stage autoimmune diseases.     

Neurotrophic Factors,Clinical Features and Gender Differences in Depression

Recent studies have evaluated the role of brain-derived neurotrophic factor (BDNF) in mood disorders; however, little is known about alterations in nerve growth factor (NGF) and glial cell line-derived neurotrophic factor (GDNF). The aim of this study was to evaluate differences among serum neurotrophic factors (BDNF, NGF and GDNF) in depressed patients and healthy controls and to verify the association between serum neurotrophic levels and clinical characteristics in a young, depressed population stratified by gender. This is a cross-sectional study with depressed patients and population controls 18–29 years of age. The concentrations of neurotrophic factors were determined by the ELISA method. The diagnosis of depression and the duration of the disease were assessed by the Structured Clinical Interview according to the diagnostic and statistical manual of mental disorders. Depression severity was measured with the 17-item Hamilton Rating Scale for Depression, and the severity of anxiety symptoms was measured using the Hamilton Anxiety Rating Scale. Serum BDNF and GDNF were lower in major depressive disorder (MDD) patients compared to controls (p ≤ 0.001). Serum NGF levels were higher in MDD patients versus controls (p ≤ 0.001). BDNF was associated with the duration of disease only in women (p = 0.005). GDNF was not associated with clinical characteristics in either gender. In women, NGF was associated with the severity of depressive symptoms (p = 0.009), anxiety (p = 0.011) and disease duration (p = 0.005). NGF was associated with disease duration in men (p = 0.026). Our results demonstrated that significant neurochemical differences in NGF and BDNF, but not in GDNF, were associated with the clinical features of MDD when patients were stratified by gender.     

Histochemistry and electron microscopy of cold microtome (cryostat) sections of cellular fractions

Summary Cold microtome (cryostat) sections of cellular fractions prepared from a rat kidney homogenate were used for the histochemical demonstration of alkaline and acid phosphatases and of succinic dehydrogenase activities; then they were studied by light microscope. Some untreated sections and some of the acid phosphatase preparations were also examined by the electron microscope. The results are in agreement with the previous studies. The suggested method make it possible morphological and histochemical studies of an organ and of its fractions both by light and by electron microscope.With 5 Figures in the Text     

From Lab to Field: The Influence of Urban Landscapes on the Invasive Potential of Wolbachia in Brazilian Aedes aegypti Mosquitoes

Background

The symbiotic bacterium Wolbachia is currently being trialled as a biocontrol agent in several countries to reduce dengue transmission. Wolbachia can invade and spread to infect all individuals within wild mosquito populations, but requires a high rate of maternal transmission, strong cytoplasmic incompatibility and low fitness costs in the host in order to do so. Additionally, extensive differences in climate, field-release protocols, urbanization level and human density amongst the sites where this bacterium has been deployed have limited comparison and analysis of Wolbachia’s invasive potential.

Methodology/Principal Findings

We examined key phenotypic effects of the wMel Wolbachia strain in laboratory Aedes aegypti mosquitoes with a Brazilian genetic background to characterize its invasive potential. We show that the wMel strain causes strong cytoplasmic incompatibility, a high rate of maternal transmission and has no evident detrimental effect on host fecundity or fertility. Next, to understand the effects of different urban landscapes on the likelihood of mosquito survival, we performed mark-release-recapture experiments using Wolbachia-uninfected Brazilian mosquitoes in two areas of Rio de Janeiro where Wolbachia will be deployed in the future. We characterized the mosquito populations in relation to the socio-demographic conditions at these sites, and at three other future release areas. We then constructed mathematical models using both the laboratory and field data, and used these to describe the influence of urban environmental conditions on the likelihood that the Wolbachia infection frequency could reach 100% following mosquito release. We predict successful invasion at all five field sites, however the conditions by which this occurs vary greatly between sites, and are strongly influenced by the size of the local mosquito population.

Conclusions/Significance

Through analysis of laboratory, field and mathematical data, we show that the wMel strain of Wolbachia possesses the characteristics required to spread effectively in different urban socio-demographic environments in Rio de Janeiro, including those where mosquito releases from the Eliminate Dengue Program will take place.     

System Dynamics Modeling in the Evaluation of Delays of Care in ST-Segment Elevation Myocardial Infarction Patients within a Tiered Health System

Background

Mortality rates amongst ST segment elevation myocardial infarction (STEMI) patients remain high, especially in developing countries. The aim of this study was to evaluate the factors related with delays in the treatment of STEMI patients to support a strategic plan toward structural and personnel modifications in a primary hospital aligning its process with international guidelines.

Methods and Findings

The study was conducted in a primary hospital localized in Foz do Iguaçu, Brazil. We utilized a qualitative and quantitative integrated analysis including on-site observations, interviews, medical records analysis, Qualitative Comparative Analysis (QCA) and System Dynamics Modeling (SD). Main cause of delays were categorized into three themes: a) professional, b) equipment and c) transportation logistics. QCA analysis confirmed four main stages of delay to STEMI patient’s care in relation to the ‘Door-in-Door-out’ time at the primary hospital. These stages and their average delays in minutes were: a) First Medical Contact (From Door-In to the first contact with the nurse and/or physician): 7 minutes; b) Electrocardiogram acquisition and review by a physician: 28 minutes; c) ECG transmission and Percutaneous Coronary Intervention Center team feedback time: 76 minutes; and d) Patient’s Transfer Waiting Time: 78 minutes. SD baseline model confirmed the system’s behavior with all occurring delays and the need of improvements. Moreover, after model validation and sensitivity analysis, results suggested that an overall improvement of 40% to 50% in each of these identified stages would reduce the delay.

Conclusions

This evaluation suggests that investment in health personnel training, diminution of bureaucracy, and management of guidelines might lead to important improvements decreasing the delay of STEMI patients’ care. In addition, this work provides evidence that SD modeling may highlight areas where health system managers can implement and evaluate the necessary changes in order to improve the process of care.     

Survey of Surface Proteins from the Pathogenic Mycoplasma hyopneumoniae Strain 7448 Using a Biotin Cell Surface Labeling Approach

The characterization of the repertoire of proteins exposed on the cell surface by Mycoplasma hyopneumoniae (M. hyopneumoniae), the etiological agent of enzootic pneumonia in pigs, is critical to understand physiological processes associated with bacterial infection capacity, survival and pathogenesis. Previous in silico studies predicted that about a third of the genes in the M. hyopneumoniae genome code for surface proteins, but so far, just a few of them have experimental confirmation of their expression and surface localization. In this work, M. hyopneumoniae surface proteins were labeled in intact cells with biotin, and affinity-captured biotin-labeled proteins were identified by a gel-based liquid chromatography-tandem mass spectrometry approach. A total of 20 gel slices were separately analyzed by mass spectrometry, resulting in 165 protein identifications corresponding to 59 different protein species. The identified surface exposed proteins better defined the set of M. hyopneumoniae proteins exposed to the host and added confidence to in silico predictions. Several proteins potentially related to pathogenesis, were identified, including known adhesins and also hypothetical proteins with adhesin-like topologies, consisting of a transmembrane helix and a large tail exposed at the cell surface. The results provided a better picture of the M. hyopneumoniae cell surface that will help in the understanding of processes important for bacterial pathogenesis. Considering the experimental demonstration of surface exposure, adhesion-like topology predictions and absence of orthologs in the closely related, non-pathogenic species Mycoplasma flocculare, several proteins could be proposed as potential targets for the development of drugs, vaccines and/or immunodiagnostic tests for enzootic pneumonia.     

Ultrastructural Characterization of Oil Bodies in Different Coffea Species

In the coffee seed, the lipid component known as coffee oil is stored in the endosperm tissue as an energy reserve for germination and post-germination growth. This coffee constituent is present in the form of subcellular spherical oil bodies (“oleosomes”) in a typical size range of 0.2–2.5 μm. These particles are filled with an osmiophilic matrix of triglycerides, delimited by a single protein membrane, typical of oleaginous plant tissues. The object of this study is to characterize the morphology and distribution of oil bodies in different coffee species. In particular, we studied Indian samples of Coffea arabica, C. canephora, C. liberica, C. stenophylla and C. salvatrix. After appropriate fixation and preparation, the samples were examined and oil bodies characterized by optical microscopy and transmission electron microscopy. Oil bodies morphology, tissue distribution and size distribution were determined and several features of these subcellular structures were observed and discussed for the first time in the framework of a coffee inter-species comparative study.