273 research outputs found
Genetic Background Can Result in a Marked or Minimal Effect of Gene Knockout (GPR55 and CB2 Receptor) in Experimental Autoimmune Encephalomyelitis Models of Multiple Sclerosis
PMCID: PMC379391
Hemoptysis, a developing world perspective
BACKGROUND: Hemoptysis is a significant clinical presentation in respiratory medicine. Often a life threatening emergency, it mandates prompt assessment and intervention. Various investigations and management protocols are proposed globally, to advocate a standardized approach towards patients presenting with hemoptysis. It is the etiology, however, that has been known to influence clinical outcome and prognosis. With marked contrast in geographical patterns of pulmonary pathologies, etiological agents for hemoptysis vary over the world. Studies in West, usually demonstrate neoplastic and non-granulomatous causes to be the leading agents for hemoptysis. The diagnostic accuracy of various investigations and efficacy of management alternatives has been established there. Developing nations differ in their burden of diseases of lung. Lack of health resources and initiative often prevent quality research in critical areas. DESIGN: This is a retrospective observational study with a cross-sectional design in which charts of all patients admitted with the presentation of haemoptysis in the past ten years will be reviewed, at Aga Khan University Hospital, Karachi, Pakistan. A series of variables, based on previous literature on haemoptysis related to the objectives of present study, will be determined in the study. Demographics, co-morbids and etiology will be determined. Findings of various investigation modalities and their accuracy in localizing the bleeding site will be determined. Efficacy of different management strategies will also be observed. Also observed will be any complications and follow-up. DISCUSSION: Pakistan is a third world nation of over 150 million, established as highly endemic for pulmonary tuberculosis. To date no study has been generated to look into hemoptysis patterns, in this nation. Lack of evidence based medicine poses a major hindrance towards confident decision-making in the approach towards a patient presenting with hemoptysis in this country. This study is devised to obtain the first insight in this direction, from this part of the world. The etiologies, accuracy of various investigations and efficacy of treatment options will be investigated. The results and conclusions will prove to be of value not just for health administrators in this country, but many other regions that share similarities in patterns of pulmonary pathologies
AKAP12 regulates vascular integrity in zebrafish
The integrity of blood vessels controls vascular permeability and extravasation of blood cells, across the endothelium. Thus, the impairment of endothelial integrity leads to hemorrhage, edema, and inflammatory infiltration. However, the molecular mechanism underlying vascular integrity has not been fully understood. Here, we demonstrate an essential role for A-kinase anchoring protein 12 (AKAP12) in the maintenance of endothelial integrity during vascular development. Zebrafish embryos depleted of akap12 (akap12 morphants) exhibited severe hemorrhages. In vivo time-lapse analyses suggested that disorganized interendothelial cell-cell adhesions in akap12 morphants might be the cause of hemorrhage. To clarify the molecular mechanism by which the cell-cell adhesions are impaired, we examined the cell-cell adhesion molecules and their regulators using cultured endothelial cells. The expression of PAK2, an actin cytoskeletal regulator, and AF6, a connector of intercellular adhesion molecules and actin cytoskeleton, was reduced in AKAP12-depleted cells. Depletion of either PAK2 or AF6 phenocopied AKAP12-depleted cells, suggesting the reduction of PAK2 and AF6 results in the loosening of intercellular junctions. Consistent with this, overexpression of PAK2 and AF6 rescued the abnormal hemorrhage in akap12 morphants. We conclude that AKAP12 is essential for integrity of endothelium by maintaining the expression of PAK2 and AF6 during vascular development
Antimicrobial agents – optimising the ecological balance
10.1186/s12916-016-0661-zBMC Medicine14111
Treating cofactors can reverse the expansion of a primary disease epidemic
<p>Abstract</p> <p>Background</p> <p>Cofactors, "nuisance" conditions or pathogens that affect the spread of a primary disease, are likely to be the norm rather than the exception in disease dynamics. Here we present a "simplest possible" demographic model that incorporates two distinct effects of cofactors: that on the transmission of the primary disease from an infected host bearing the cofactor, and that on the acquisition of the primary disease by an individual that is not infected with the primary disease but carries the cofactor.</p> <p>Methods</p> <p>We constructed and analyzed a four-patch compartment model that accommodates a cofactor. We applied the model to HIV spread in the presence of the causal agent of genital schistosomiasis, <it>Schistosoma hematobium</it>, a pathogen commonly co-occurring with HIV in sub-Saharan Africa.</p> <p>Results</p> <p>We found that cofactors can have a range of effects on primary disease dynamics, including shifting the primary disease from non-endemic to endemic, increasing the prevalence of the primary disease, and reversing demographic growth when the host population bears only the primary disease to demographic decline. We show that under parameter values based on the biology of the HIV/<it>S. haematobium </it>system, reduction of the schistosome-bearing subpopulations (e.g. through periodic use of antihelminths) can slow and even reverse the spread of HIV through the host population.</p> <p>Conclusions</p> <p>Typical single-disease models provide estimates of future conditions and guidance for direct intervention efforts relating only to the modeled primary disease. Our results suggest that, in circumstances under which a cofactor affects the disease dynamics, the most effective intervention effort might not be one focused on direct treatment of the primary disease alone. The cofactor model presented here can be used to estimate the impact of the cofactor in a particular disease/cofactor system without requiring the development of a more complicated model which incorporates many other specific aspects of the chosen disease/cofactor pair. Simulation results for the HIV/<it>S. haematobium </it>system have profound implications for disease management in developing areas, in that they provide evidence that in some cases treating cofactors may be the most successful and cost-effective way to slow the spread of primary diseases.</p
Differential Requirement for Utrophin in the Induced Pluripotent Stem Cell Correction of Muscle versus Fat in Muscular Dystrophy Mice
Duchenne muscular dystrophy (DMD) is an incurable degenerative muscle disorder. We injected WT mouse induced pluripotent stem cells (iPSCs) into mdx and mdx∶utrophin mutant blastocysts, which are predisposed to develop DMD with an increasing degree of severity (mdx <<< mdx∶utrophin). In mdx chimeras, iPSC-dystrophin was supplied to the muscle sarcolemma to effect corrections at morphological and functional levels. Dystrobrevin was observed in dystrophin-positive and, at a lesser extent, utrophin-positive areas. In the mdx∶utrophin mutant chimeras, although iPSC-dystrophin was also supplied to the muscle sarcolemma, mice still displayed poor skeletal muscle histopathology, and negligible levels of dystrobrevin in dystrophin- and utrophin-negative areas. Not only dystrophin-expressing tissues are affected by iPSCs. Mdx and mdx∶utrophin mice have reduced fat/body weight ratio, but iPSC injection normalized this parameter in both mdx and mdx∶utrophin chimeras, despite the fact that utrophin was compromised in the mdx∶utrophin chimeric fat. The results suggest that the presence of utrophin is required for the iPSC-corrections in skeletal muscle. Furthermore, the results highlight a potential (utrophin-independent) non-cell autonomous role for iPSC-dystrophin in the corrections of non-muscle tissue like fat, which is intimately related to the muscle
Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre
The cores of most galaxies are thought to harbour supermassive black holes,
which power galactic nuclei by converting the gravitational energy of accreting
matter into radiation (ref 1). Sagittarius A*, the compact source of radio,
infrared and X-ray emission at the centre of the Milky Way, is the closest
example of this phenomenon, with an estimated black hole mass that is 4 million
times that of the Sun (refs. 2,3). A long-standing astronomical goal is to
resolve structures in the innermost accretion flow surrounding Sgr A* where
strong gravitational fields will distort the appearance of radiation emitted
near the black hole. Radio observations at wavelengths of 3.5 mm and 7 mm have
detected intrinsic structure in Sgr A*, but the spatial resolution of
observations at these wavelengths is limited by interstellar scattering (refs.
4-7). Here we report observations at a wavelength of 1.3 mm that set a size of
37 (+16, -10; 3-sigma) microarcseconds on the intrinsic diameter of Sgr A*.
This is less than the expected apparent size of the event horizon of the
presumed black hole, suggesting that the bulk of SgrA* emission may not be not
centred on the black hole, but arises in the surrounding accretion flow.Comment: 12 pages including 2 figure
Seroprevalence and factors associated with herpes simplex virus type 2 among HIV-negative high-risk men who have sex with men from Rio de Janeiro, Brazil: a cross-sectional study
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Previous issue date: 2009Fundação Oswaldo Cruz. Instituto de Pesquisa Clínica Evandro Chagas. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto de Pesquisa Clínica Evandro Chagas. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto de Comunicação e Informação Científica e Tecnológica em Saúde. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto de Pesquisa Clínica Evandro Chagas. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto de Pesquisa Clínica Evandro Chagas. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto de Pesquisa Clínica Evandro Chagas. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto de Pesquisa Clínica Evandro Chagas. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto de Pesquisa Clínica Evandro Chagas. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto de Pesquisa Clínica Evandro Chagas. Rio de Janeiro, RJ, Brasil.Background: Herpes simplex virus type 2 (HSV-2) is the leading cause of genital ulcer disease in
developing countries, including Brazil, and is especially prevalent among men who have sex with
men (MSM). HSV-2 infection represents a risk factor for the acquisition and transmission of other
sexually transmitted diseases. The goal of the present cross-sectional study was to estimate HSV-
2 seroprevalence and to determine the factors associated with HSV-2 seropositivity in HIVnegative
high-risk MSM from Rio de Janeiro, Brazil.
Methods: Stored sera were tested to estimate HSV-2 seroprevalence, while socio-demographic
and sexual behavior data were used to measure associations between risk factors and HSV-2
seropositivity. Using the Poisson regression model with robust variance, prevalence ratios (PR)
were used to estimate de degree of association between risk factors and HSV-2 seropositivity in
bivariate and multivariate analyses.
Results: Seroprevalence of HSV-2 was of 45.7% (184 out of 403). Factors independently associated
with HSV-2 seroprevalence in the multivariate model were: older age (≥ 26 years, PR: 1.41 95%
Confidence Interval: 1.11–1.78), non-white race (PR: 1.32 95%CI: 1.06–1.64), positive serology for
syphilis (PR: 1.65 95%CI: 1.33–2.05), positive serology for hepatitis B (PR: 1.25 95%CI: 0.99–1.57),
stable male partner in the past 6 months (PR: 1.42 95%CI: 1.12–1.79), and unprotected anal sex
with a stable female partner (PR: 1.46 95%CI: 1.05–2.04) in the 6 months preceding the crosssectional
assessment.
Conclusion: The present study made evident a high prevalence of HSV-2 infection in a sample of
HIV-negative high-risk MSM from Rio de Janeiro. This finding indicates the need and urgency for
implementing integrated programs for the prevention of HSV-2 and other sexually transmitted
diseases, and, in particular, programs targeting high-risk MSM
Properly Folded Bacterially Expressed H1N1 Hemagglutinin Globular Head and Ectodomain Vaccines Protect Ferrets against H1N1 Pandemic Influenza Virus
Background: In the face of impending influenza pandemic, a rapid vaccine production and mass vaccination is the most effective approach to prevent the large scale mortality and morbidity that was associated with the 1918 "Spanish Flu". The traditional process of influenza vaccine production in eggs is time consuming and may not meet the demands of rapid global vaccination required to curtail influenza pandemic. Methodology/Principal Findings: Recombinant technology can be used to express the hemagglutinin (HA) of the emerging new influenza strain in a variety of systems including mammalian, insect, and bacterial cells. In this study, two forms of HA proteins derived from the currently circulating novel H1N1 A/California/07/2009 virus, HA1 (1-330) and HA (1- 480), were expressed and purified from E. coli under controlled redox refolding conditions that favoured proper protein folding. However, only the recombinant HA1 (1-330) protein formed oligomers, including functional trimers that bound receptor and caused agglutination of human red blood cells. These proteins were used to vaccinate ferrets prior to challenge with the A/California/07/2009 virus. Both proteins induced neutralizing antibodies, and reduced viral loads in nasal washes. However, the HA1 (1-330) protein that had higher content of multimeric forms provided better protection from fever and weight loss at a lower vaccine dose compared with HA (1-480). Protein yield for the HA1 (1-330) ranged around 40 mg/Liter, while the HA (1-480) yield was 0.4-0.8 mg/Liter. Conclusions/Significance: This is the first study that describes production in bacterial system of properly folded functional globular HA1 domain trimers, lacking the HA2 transmembrane protein, that elicit potent neutralizing antibody responses following vaccination and protect ferrets from in vivo challenge. The combination of bacterial expression system with established quality control methods could provide a mechanism for rapid large scale production of influenza vaccines in the face of influenza pandemic threat
Altered monocyte and fibrocyte phenotype and function in scleroderma interstitial lung disease: reversal by caveolin-1 scaffolding domain peptide
Interstitial lung disease (ILD) is a major cause of morbidity and mortality in scleroderma (systemic sclerosis, or SSc). Fibrocytes are a monocyte-derived cell population implicated in the pathogenesis of fibrosing disorders. Given the recently recognized importance of caveolin-1 in regulating function and signaling in SSc monocytes, in the present study we examined the role of caveolin-1 in the migration and/or trafficking and phenotype of monocytes and fibrocytes in fibrotic lung disease in human patients and an animal model. These studies fill a gap in our understanding of how monocytes and fibrocytes contribute to SSc-ILD pathology. We found that C-X-C chemokine receptor type 4-positive (CXCR4+)/collagen I-positive (ColI+), CD34+/ColI+ and CD45+/ColI+ cells are present in SSc-ILD lungs, but not in control lungs, with CXCR4+ cells being most prevalent. Expression of CXCR4 and its ligand, stromal cell-derived factor 1 (CXCL12), are also highly upregulated in SSc-ILD lung tissue. SSc monocytes, which lack caveolin-1 and therefore overexpress CXCR4, exhibit almost sevenfold increased migration toward CXCL12 compared to control monocytes. Restoration of caveolin-1 function by administering the caveolin scaffolding domain (CSD) peptide reverses this hypermigration. Similarly, transforming growth factor β-treated normal monocytes lose caveolin-1, overexpress CXCR4 and exhibit 15-fold increased monocyte migration that is CSD peptide-sensitive. SSc monocytes exhibit a different phenotype than normal monocytes, expressing high levels of ColI, CD14 and CD34. Because ColI+/CD14+ cells are prevalent in SSc blood, we looked for such cells in lung tissue and confirmed their presence in SSc-ILD lungs but not in normal lungs. Finally, in the bleomycin model of lung fibrosis, we show that CSD peptide diminishes fibrocyte accumulation in the lungs. Our results suggest that low caveolin-1 in SSc monocytes contributes to ILD via effects on cell migration and phenotype and that the hyperaccumulation of fibrocytes in SSc-ILD may result from the altered phenotype and migratory activity of their monocyte precursors
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