Effects of Optically Imposed Astigmatism on Early Eye Growth in Chicks

PurposeTo determine the effects of optically imposed astigmatism on early eye growth in chicks.Methods5-day-old (P5) White Leghorn chicks were randomly assigned to either wear, monocularly, a “high magnitude” (H: +4.00DS/-8.00DC) crossed-cylindrical lens oriented at one of four axes (45, 90, 135, and 180; n = 20 in each group), or were left untreated (controls; n = 8). Two additional groups wore a “low magnitude” (L: +2.00DS/−4.00DC) cylindrical lens orientated at either axis 90 or 180 (n = 20 and n = 18, respectively). Refractions were measured at P5 and after 7 days of treatment for all chicks (P12), whereas videokeratography and ex-vivo eyeshape analysis were performed at P12 for a subset of chicks in each group (n = 8).ResultsCompared to controls, chicks in the treatment groups developed significant amounts of refractive astigmatism (controls: 0.03±0.22DC; treatment groups: 1.34±0.22DC to 5.51±0.26DC, one-way ANOVAs, p≤0.05) with axes compensatory to those imposed by the cylindrical lenses. H cylindrical lenses induced more refractive astigmatism than L lenses (H90 vs. L90: 5.51±0.26D vs. 4.10±0.16D; H180 vs. L180: 2.84±0.44D vs. 1.34±0.22D, unpaired two-sample t-tests, both p≤0.01); and imposing with-the-rule (H90 and L90) and against-the-rule astigmatisms (H180 and L180) resulted in, respectively, steeper and flatter corneal shape. Both corneal and internal astigmatisms were moderately to strongly correlated with refractive astigmatisms (Pearson’s r: +0.61 to +0.94, all p≤0.001). In addition, the characteristics of astigmatism were significantly correlated with multiple eyeshape parameters at the posterior segments (Pearson’s r: -0.27 to +0.45, all p≤0.05).ConclusionsChicks showed compensatory ocular changes in response to the astigmatic magnitudes imposed in this study. The correlations of changes in refractive, corneal, and posterior eyeshape indicate the involvement of anterior and posterior ocular segments during the development of astigmatism.     

Dynamic expression of a LEF‐EGFP Wnt reporter in mouse development and cancer

We have characterized a transgenic mouse line in which enhanced green fluorescent protein (EGFP) is expressed under the control of multimerized LEF‐1 responsive elements. In embryos, EGFP was detected in known sites of Wnt activation, including the primitive streak, mesoderm, neural tube, somites, heart, limb buds, mammary placodes, and whisker follicles. In vitro cultured transgenic embryonic fibroblasts upregulated EGFP expression in response to activation of Wnt signaling by GSK3β inhibition. Mammary tumor cell lines derived from female LEF‐EGFP transgenic mice treated with the carcinogen 7, 12‐dimethylbenz[a]anthracene (DMBA) also express EGFP. Thus, this transgenic line is useful for ex vivo and in vitro studies of Wnt signaling in development and cancer. genesis 48:183–194, 2010. © 2010 Wiley‐Liss, Inc.     

Formulation and Evaluation of Buccal Patches for Delivery of Atenolol

Buccal patches for the delivery of atenolol using sodium alginate with various hydrophilic polymers like carbopol 934 P, sodium carboxymethyl cellulose, and hydroxypropyl methylcellulose in various proportions and combinations were fabricated by solvent casting technique. Various physicomechanical parameters like weight variation, thickness, folding endurance, drug content, moisture content, moisture absorption, and various ex vivo mucoadhesion parameters like mucoadhesive strength, force of adhesion, and bond strength were evaluated. An in vitro drug release study was designed, and it was carried out using commercial semipermeable membrane. All these fabricated patches were sustained for 24 h and obeyed first-order release kinetics. Ex vivo drug permeation study was also performed using porcine buccal mucosa, and various drug permeation parameters like flux and lag time were determined.     

Lactobacilli secreting a tumor antigen and IL15 activates neutrophils and dendritic cells and generates cytotoxic T lymphocytes against cancer cells

Lactobacillus rhamnosus GG (LGG) has been used to successfully induce tumor regression in an orthotopic model of bladder cancer. Increased infiltration of neutrophils and macrophages into the tumor mass was observed after therapy. This study evaluates the potential of LGG to induce a directed anti-tumor response. Lactobacilli were modified to secrete the prostate specific antigen (PSA) or IL15 and PSA (IL-15-PSA). Neutrophils and DC were exposed to LGG for 2 h as in clinical therapy for bladder cancer. Recombinant LGG activated neutrophils (elevated MHC class I expression) induced DC maturation (increased expression of CD86, CD80, CD40, MHC II and CD83), T cell proliferation and PSA specific cytotoxic T lymphocytes (CTL) activity. IL15 enhanced direct DC activation of CTL. Thus LGG secreting tumor antigens may activate antigen specific immune responses when instilled intravesically and IL15 could enhance this response.     

Unique Hepatic Cytosolic Arginase Evolved Independently in Ureogenic Freshwater Air-Breathing Teleost,Heteropneustes fossilis

Hepatic cytosolic arginase (ARG I), an enzyme of the urea cycle operating in the liver of ureotelic animals, is reported to be present in an ammoniotelic freshwater air-breathing teleost, Heteropneustes fossilis which has ureogenic potential. Antibodies available against mammalian ARG I showed no cross reactivity with the H. fossilis ARG I. We purified unique ARG I from H. fossilis liver. Purified ARG I is a homotrimer with molecular mass 75 kDa and subunit molecular mass of 24 kDa. The pI value of the enzyme was 8.5. It showed maximum activity at pH 10.5 and 55°C. The Km of purified enzyme for L-arginine was 2.65±0.39 mM. L-ornithine and N^ω-hydroxy-L-arginine showed inhibition of the ARG I activity, with Ki values 0.52±0.02mM and 0.08±0.006mM, respectively. Antibody raised against the purified fish liver ARG I showed exclusive specificity, and has no cross reactivity against fish liver ARG II and mammalian liver ARG I and ARG II. We found another isoform of arginase bound to the outer membrane of the mitochondria which was released by 150–200 mM KCl in the extraction medium. This isoform was immunologically different from the soluble cytosolic and mitochondrial arginase. The results of present study support that hepatic cytosolic arginase evolved in this ureogenic freshwater teleost, H. fossilis. Phylogenetic analysis confirms an independent evolution event that occurred much after the evolution of the cytosolic arginase of ureotelic vertebrates.     

How accurate and statistically robust are catalytic site predictions based on closeness centrality?

Background  

We examine the accuracy of enzyme catalytic residue predictions from a network representation of protein structure. In this model, amino acid α-carbons specify vertices within a graph and edges connect vertices that are proximal in structure. Closeness centrality, which has shown promise in previous investigations, is used to identify important positions within the network. Closeness centrality, a global measure of network centrality, is calculated as the reciprocal of the average distance between vertex i and all other vertices.     

Entomological outcomes of cluster-randomised,community-driven dengue vector-suppression interventions in Kampong Cham province,Cambodia

Cambodia has one of the highest dengue infection rates in Southeast Asia. Here we report quantitative entomological results of a large-scale cluster-randomised trial assessing the impact on vector populations of a package of vector control interventions including larvivorous guppy fish in household water containers, mosquito trapping with gravid-ovitraps, solid waste management, breeding-container coverage through community education and engagement for behavioural change, particularly through the participation of school children. These activities resulted in major reductions in Container Index, House Index, Breteau Index, Pupal Index and Adult Index (all p-values 0.002 or lower) in the Intervention Arm compared with the Control Arm in a series of household surveys conducted over a follow-up period of more than one year, although the project was not able to measure the longer-term sustainability of the interventions. Despite comparative reductions in Adult Index between the study arms, the Adult Index was higher in the Intervention Arm in the final household survey than in the first household survey. This package of biophysical and community engagement interventions was highly effective in reducing entomological indices for dengue compared with the control group, but caution is required in extrapolating the reduction in household Adult Index to a reduction in the overall population of adult Aedes mosquitoes, and in interpreting the relationship between a reduction in entomological indices and a reduction in the number of dengue cases. The package of interventions should be trialled in other locations.     

Heme models of peroxidase enzymes: deuteroferriheme-catalyzed chlorination of monochlorodimedone by sodium chlorite

The iron(III) complex of deuteroporphyrin(IX), deuteroferriheme, catalyzes the chlorination, by sodium chlorite, of the active methylene compound monochlorodimedone (MCD) to dichlorodimedone. Rate studies, carried out on a stopped-flow spectrophotometric time scale, show the chlorination to be zero-order in MCD, first-order in ClO2- and to display a complex dependence on heme. The active chlorinating agent is believed to be hypochlorite, OCl-, formed as a result of the initial two-electron oxidation of heme to peroxidatic intermediate by chlorite ion. This scheme is supported by the fact that the normal (4:1) heme:ClO2- molar stoichiometry is reduced in the presence of MCD to values approaching 2:1. This suggests that MCD is an effective scavenger of OCl-, which, in the absence of active methylene compound, serves as a two-electron oxidant of heme. The zero-order dependence of rate on MCD is attributed to the slow formation of OCl-, consequent to a mechanism in which the rate-limiting step is viewed to be the regeneration of free heme from peroxidatic intermediate, probably via a catalatic pathway. Support for such a mechanism is provided by the fact that addition of ascorbate greatly enhances the rate of MCD chlorination, presumably by accelerating the rate of heme regeneration via perioxidation reduction of the heme intermediate.     

Phospholipid composition and metabolism in mouse muscular dystrophy

1. The uptake of monosaccharides and polyols in the obligatory aerobic yeast Rhodotorula gracilis (glutinis) was accompanied by proton uptake. 2. The half-saturation constant of transport, KT, depended on pH, changing from about 2mM at pH 4.5 to 80mM at pH8.5 for D-xylose; this change of the effective carrier affinity was reversible. 3. The apparent dissociation constant of the monosaccharide carrier was estimated at pKa 6.75. 4. At pH8.5, when the pH gradient across the cell membrane vanished, no sugar accumulation was demonstrable. 5. The half-saturation constants of sugar uptake and H+ co-transport were very similar to each other, the latter obviously being controlled by the former. 6. The H+/sugar stoicheiometry remained constant under various physiological conditions; it amounted to one H+ ion per sugar molecule taken up. 7. The data are interpreted as a strong piece of evidence in favour of the active monosaccharide transport in R. gracilis (glutinis) being an H+-symport energized by the electrochemical gradient of H+ across the plasma membrane of the yeast.