Preparation and in vitro evaluation of xanthan gum facilitated superabsorbent polymeric microspheres

Interpenetrating polymer network (IPN) hydrogel microspheres of xanthan gum (XG) based superabsorbent polymer (SAP) and poly(vinyl alcohol) (PVA) were prepared by water-in-oil (w/o) emulsion crosslinking method for sustained release of ciprofloxacin hydrochloride (CIPRO). The microspheres were prepared with various ratios of hydrolyzed SAP to PVA and extent of crosslinking density. The prepared microspheres with loose and rigid surfaces were evidenced by scanning electron microscope (SEM). Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis confirmed the IPN formation. Differential scanning calorimetry (DSC) study was performed to understand the dispersion nature of drug after encapsulation. The in vitro drug release study was extensively evaluated depending on the process variables in both acidic and alkaline media. All the formulations exhibited satisfactory physicochemical and in vitro release characteristics. Release data indicated a non-Fickian trend of drug release from the formulations. Based on the results, this study suggest that CIPRO loaded IPN microspheres were suitable for sustained release application.     

Ionic Currents of Human Trabecular Meshwork Cells from Control and Glaucoma Subjects

Increasing evidence suggests that trabecular meshwork (TM) cells participate in the regulation of intraocular pressure by controlling the rate of filtration of the aqueous humor. Ionic conductances that regulate cell volume and shape have been suggested to play an important role in TM cell volume regulation. Here, we compared ionic currents from TM cells derived from a normal subject (CTM) and from an individual affected by glaucoma (GTM). We found that while the ionic current types were similar, the current amplitudes and percentage of cells endowed with specific current at baseline were different in the two cell lines. Thus, we found that the majority of CTM cells were endowed with a swelling-activated Cl^? current at baseline, whereas in the majority of GTM cells this current was not active at baseline and became activated only after perfusion with a hypotonic solution. An inward rectifier K⁺ current was also more prevalent in CTM than in GTM cells. Our work suggests that disregulation of one or more of these ionic currents may be at the basis of TM cell participation in the development of glaucoma.     

A Pivotal Role for Tryptophan 447 in Enzymatic Coupling of Human Endothelial Nitric Oxide Synthase (eNOS): EFFECTS ON TETRAHYDROBIOPTERIN-DEPENDENT CATALYSIS AND eNOS DIMERIZATION*

Tetrahydrobiopterin (BH4) is a required cofactor for the synthesis of NO by NOS. Bioavailability of BH4 is a critical factor in regulating the balance between NO and superoxide production by endothelial NOS (eNOS coupling). Crystal structures of the mouse inducible NOS oxygenase domain reveal a homologous BH4-binding site located in the dimer interface and a conserved tryptophan residue that engages in hydrogen bonding or aromatic stacking interactions with the BH4 ring. The role of this residue in eNOS coupling remains unexplored. We overexpressed human eNOS W447A and W447F mutants in novel cell lines with tetracycline-regulated expression of human GTP cyclohydrolase I, the rate-limiting enzyme in BH4 synthesis, to determine the importance of BH4 and Trp-447 in eNOS uncoupling. NO production was abolished in eNOS-W447A cells and diminished in cells expressing W447F, despite high BH4 levels. eNOS-derived superoxide production was significantly elevated in W447A and W447F versus wild-type eNOS, and this was sufficient to oxidize BH4 to 7,8-dihydrobiopterin. In uncoupled, BH4-deficient cells, the deleterious effects of W447A mutation were greatly exacerbated, resulting in further attenuation of NO and greatly increased superoxide production. eNOS dimerization was attenuated in W447A eNOS cells and further reduced in BH4-deficient cells, as demonstrated using a novel split Renilla luciferase biosensor. Reduction of cellular BH4 levels resulted in a switch from an eNOS dimer to an eNOS monomer. These data reveal a key role for Trp-447 in determining NO versus superoxide production by eNOS, by effects on BH4-dependent catalysis, and by modulating eNOS dimer formation.     

Identification and characterization of autotransporter proteins of Yersinia pestis KIM

Yersinia pestis is a Gram-negative bacterium that causes plague. Currently, plague is considered a re-emerging infectious disease and Y. pestis a potential bioterrorism agent. Autotransporters (ATs) are virulence proteins translocated by a variety of pathogenic Gram-negative bacteria across the cell envelope to the cell surface or extracellular environment. In this study, we screened the genome of Yersinia pestis KIM for AT genes whose expression might be relevant for the pathogenicity of this plague-causing organism. By in silico analyses, we identified ten putative AT genes in the genomic sequence of Y. pestis KIM; two of these genes are located within known pathogenicity islands. The expression of all ten putative AT genes in Y. pestis KIM was confirmed by RT-PCR. Five genes, designated yapA, yapC, yapG, yapK and yapN, were subsequently cloned and expressed in Escherichia coli K12 for protein secretion studies. Two forms of the YapA protein (130 kDa and 115 kDa) were found secreted into the culture medium. Protease cleavage at the C terminus of YapA released the protein from the cell surface. Outer membrane localization of YapC (65 kDa), YapG (100 kDa), YapK (130 kDa), and YapN (60 kDa) was established by cell fractionation, and cell surface localization of YapC and YapN was demonstrated by protease accessibility experiments. In functional studies, YapN and YapK showed hemagglutination activity and YapC exhibited autoagglutination activity. Data reported here represent the first study on Y. pestis ATs.     

A multifaceted strategy using mobile technology to assist rural primary healthcare doctors and frontline health workers in cardiovascular disease risk management: protocol for the SMARTHealth India cluster randomised controlled trial

Background

Blood Pressure related disease affected 118 million people in India in the year 2000; this figure will double by 2025. Around one in four adults in rural India have hypertension, and of those, only a minority are accessing appropriate care. Health systems in India face substantial challenges to meet these gaps in care, and innovative solutions are needed.

Methods

We hypothesise that a multifaceted intervention involving capacity strengthening of primary healthcare doctors and non-physician healthcare workers through use of a mobile device-based clinical decision support system will result in improved blood pressure control for individuals at high risk of a cardiovascular disease event when compared with usual healthcare. This intervention will be implemented as a stepped wedge, cluster randomised controlled trial in 18 primary health centres and 54 villages in rural Andhra Pradesh involving adults aged ≥40 years at high cardiovascular disease event risk (approximately 15,000 people). Cardiovascular disease event risk will be calculated based on World Health Organisation/International Society of Hypertension’s region-specific risk charts. Cluster randomisation will occur at the level of the primary health centres. Outcome analyses will be conducted blinded to intervention allocation.

Expected outcomes

The primary study outcome is the difference in the proportion of people meeting guideline-recommended blood pressure targets in the intervention period vs. the control period. Secondary outcomes include mean reduction in blood pressure levels; change in other cardiovascular disease risk factors, including body mass index, current smoking, reported healthy eating habits, and reported physical activity levels; self-reported use of blood pressure and other cardiovascular medicines; quality of life (using the EQ-5D); and cardiovascular disease events (using hospitalisation data). Trial outcomes will be accompanied by detailed process and economic evaluations.

Significance

The findings are likely to inform policy on a scalable strategy to overcome entrenched inequities in access to effective healthcare for under-served populations in low and middle income country settings.

Trial registration

Clinical Trial Registry India CTRI/2013/06/003753.

     

Navigating abstract virtual environment: an eeg study

Perceptions of different environments are different for different people. An abstract designed environment, with a degree of freedom from any visual reference in the physical world requests a completely different perception than a fully or semi-designed environment that has some correlation with the physical world. Maximal evidence on the manner in which the human brain is involved/operates in dealing with such novel perception comes from neuropsychology. Harnessing the tools and techniques involved in the domain of neuropsychology, the paper presents nee evidence on the role of pre-central gyrus in the perception of abstract spatial environments. In order to do so, the research team developed three different categories of designed environment with different characteristics: (1) Abstract environment, (2) Semi-designed environment, (3) Fully designed environment, as experimental sample environments. Perception of Fully-designed and semi-designed environments is almost the same, [maybe] since the brain can find a correlation between designed environments and already experienced physical world. In addition to this, the response to questionnaires accompanied with a list of buzzwords that have been provided after the experiments, also describe the characteristics of the chosen sample environments. Additionally, these results confirm the suitability of continuous electroencephalography (EEG) for studying Perception from the perspective of architectural environments.     

Potential for Controlling Cholera Using a Ring Vaccination Strategy: Re-analysis of Data from a Cluster-Randomized Clinical Trial

IntroductionVaccinating a buffer of individuals around a case (ring vaccination) has the potential to target those who are at highest risk of infection, reducing the number of doses needed to control a disease. We explored the potential vaccine effectiveness (VE) of oral cholera vaccines (OCVs) for such a strategy.ConclusionsThese findings suggest that high-level protection can be achieved if individuals living close to cholera cases are living in a high coverage ring. Since this was an observational study including participants who had received two doses of vaccine (or placebo) in the clinical trial, further studies are needed to determine whether a ring vaccination strategy, in which vaccine is given quickly to those living close to a case, is feasible and effective.

Trial registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00289224","term_id":"NCT00289224"}}NCT00289224     

Induction of IL-10 and TGFβ from CD4+CD25+FoxP3+ T Cells Correlates with Parasite Load in Indian Kala-azar Patients Infected with Leishmania donovani

Background

Visceral leishmaniasis (VL) is distinguished by a complex interplay of immune response and parasite multiplication inside host cells. However, the direct association between different immunological correlates and parasite numbers remains largely unknown.

Methodology/Principal Findings

We examined the plasma levels of different disease promoting/protective as well as Th17 cytokines and found IL-10, TGFβ and IL-17 to be significantly correlated with parasite load in VL patients (r = 0.52, 0.53 and 0.51 for IL-10, TGFβ and IL-17, respectively). We then extended our investigation to a more antigen-specific response and found leishmanial antigen stimulated levels of both IL-10 and TGFβ to be significantly associated with parasite load (r = 0.71 and 0.72 for IL-10 and TGFβ respectively). In addition to cytokines we also looked for different cellular subtypes that could contribute to cytokine secretion and parasite persistence. Our observations manifested an association between different Treg cell markers and disease progression as absolute numbers of CD4⁺CD25⁺ (r = 0.55), CD4⁺CD25^hi (r = 0.61) as well as percentages of CD4⁺CD25⁺FoxP3⁺ T cells (r = 0.68) all correlated with parasite load. Encouraged by these results, we investigated a link between these immunological components and interestingly found both CD4⁺CD25⁺ and CD4⁺CD25⁺FoxP3⁺ Treg cells to secrete significantly (p<0.05) higher amounts of not only IL-10 but also TGFβ in comparison to corresponding CD25^- T cells.

Conclusions/Significance

Our findings shed some light on source(s) of TGFβ and suggest an association between these disease promoting cytokines and Treg cells with parasite load during active disease. Moreover, the direct evidence of CD4⁺CD25⁺FoxP3⁺ Treg cells as a source of IL-10 and TGFβ during active VL could open new avenues for immunotherapy towards cure of this potentially fatal disease.