Ultrastructural immunocytochemical localization of fibronectin deposition during corneal endothelial wound repair. Evidence for cytoskeletal involvement

The distribution of the extracellular matrix (ECM) protein, fibronectin (FN), has been examined ultrastructurally in noninjured and injured rat corneal endothelium in vivo and in vitro by immunoperoxidase cytochemistry. In noninjured endothelia, FN was observed within the rough endoplasmic reticulum (RER) cisternae but not along the cell-Descemet's membrane (DM) interface. Twenty-four and 48 h after a circular freeze injury, immunoperoxidase reaction product was detected at the cell-DM interface as well as within cytoplasmic vesicles and intercellular spaces. By 1 and 2 wk post-injury, a line of reaction product could still be demonstrated at the cell-DM interface and evidence for newly deposited basement membrane material was observed in this region. In order to understand whether fibronectin deposition during wound repair was dependent on cytoskeletal influences, organ culture experiments were performed in which the media was supplemented with either 10(-8) M colchicine or 2.5 X 10(-3) M cytochalasin B. Without inhibitors, injured corneas cultured for 24 h had FN deposition at the cell-DM interface similar to the in vivo results. Corneas cultured in the presence of cytochalasin B also showed FN deposition at the cell-DM interface. However, when injured endothelia were cultured in the presence of colchicine, no reaction product was observed at the cell-DM interface, although it could be detected intracellularly within RER. Incubating the tissues in the presence of puromycin abolished all extracellular and intracellular staining. These results indicate that during wound repair, corneal endothelial cells produce fibronectin and deposit it upon Descemet's membrane by a mechanism that may be mediated by microtubules.     

Biocompatible scaffolds based on collagen and oxidized dextran for endothelial cell survival and function in tissue engineering

Angiogenesis is a vital step in tissue regeneration. Hence, the current study aimed to prepare oxidized dextran (Odex)/collagen (Col)-hydrogels with laminin (LMN), as an angiogenic extracellular matrix (ECM) component, for promoting human umbilical vein endothelial cell (HUVEC) proliferation and function. Odex/Col scaffolds were constructed at various concentrations and temperatures. Using oscillatory rheometry, scanning electron microscopy (SEM), and cell viability testing, the scaffolds were characterized, and then HUVEC proliferation and function was compared with or without LMN. The gelation time could be modified by altering the Odex/Col mass ratio as well as the temperature. SEM showed that Odex/Col hydrogels had a more regular three-dimensional (3D) porous structure than the Col hydrogels. Moreover, HUVECs grew faster in the Col scaffold (12 mg/mL), whereas the Odex (30 mg/mL)/Col (6 mg/mL) scaffold exhibited the lowest apoptosis index. Furthermore, the expression level of vascular endothelial growth factor (VEGF) mRNA in the group without LMN was higher than that with LMN, and the Odex (30 mg/mL)/Col (6 mg/mL) scaffold without LMN had the highest VEGF protein secretion, allowing the cells to survive and function effectively. Odex/Col scaffolds, with or without LMN, are proposed as a tissue engineering construct to improve HUVEC survival and function for angiogenesis.     

Aluminium toxicity during regular haemodialysis.

In the west of Scotland the incidence of dialysis encephalopathy has been confined to three geographical areas where the concentration of aluminium in the water supply is greatly increased owing to the addition of aluminium sulphate. Eight patients with encephalopathy who dialysed at home in these areas had greatly increased serum aluminium concentrations, and a significant correlation was found between serum aluminium concentrations and the concentrations of aluminium in the water supply. This study provides further evidence that the dialysis encephalopathy syndrome is due to aluminium intoxication, the major source of aluminium being the water supply from which dialysis fluid prepared.     

A 3D structural model and dynamics of hepatitis C virus NS3/4A protease (genotype 4a,strain ED43) suggest conformational instability of the catalytic triad: implications in catalysis and drug resistivity

Egypt has the highest prevalence of hepatitis C virus (HCV) infection worldwide with a frequency of 15%. More than 90% of these infections are due to genotype 4, and the subtype 4a (HCV-4a) predominates. Moreover, due to the increased mobility of people, HCV-4a has recently spread to several European countries. The protease domain of the HCV nonstructural protein 3 (NS3) has been targeted for inhibition by several drugs. This approach has had marked success in inhibiting genotype 1 (HCV-1), the predominant genotype in the USA, Europe, and Japan. However, HCV-4a was found to resist inhibition by a number of these drugs, and little progress has been made to understand the structural basis of its drug resistivity. As a step forward, we sequenced the NS3 HCV-4a protease gene (strain ED43) and subsequently built a 3D structural model threaded through a template crystal structure of HCV-1b NS3 protease. The model protease, HCV-4a, shares 83% sequence identity with the template protease, HCV-1b, and has nearly identical rigid structural features. Molecular dynamics simulations predict similar overall dynamics of the two proteases. However, local dynamics and 4D analysis of the interactions between the catalytic triad residues (His57, Asp81, and Ser139) indicate conformational instability of the catalytic site in HCV-4a NS3 protease. These results suggest that the divergent dynamics behavior, more than the rigid structure, could be related to the altered catalytic activity and drug resistivity seen in HCV-4a.     

Paternal B Vitamin Intake Is a Determinant of Growth,Hepatic Lipid Metabolism and Intestinal Tumor Volume in Female Apc1638N Mouse Offspring

Background

The importance of maternal nutrition to offspring health and risk of disease is well established. Emerging evidence suggests paternal diet may affect offspring health as well.

Objective

In the current study we sought to determine whether modulating pre-conception paternal B vitamin intake alters intestinal tumor formation in offspring. Additionally, we sought to identify potential mechanisms for the observed weight differential among offspring by profiling hepatic gene expression and lipid content.

Methods

Male Apc^1638N mice (prone to intestinal tumor formation) were fed diets containing replete (control, CTRL), mildly deficient (DEF), or supplemental (SUPP) quantities of vitamins B₂, B₆, B₁₂, and folate for 8 weeks before mating with control-fed wild type females. Wild type offspring were euthanized at weaning and hepatic gene expression profiled. Apc^1638N offspring were fed a replete diet and euthanized at 28 weeks of age to assess tumor burden.

Results

No differences in intestinal tumor incidence or burden were found between male Apc^1638N offspring of different paternal diet groups. Although in female Apc^1638N offspring there were no differences in tumor incidence or multiplicity, a stepwise increase in tumor volume with increasing paternal B vitamin intake was observed. Interestingly, female offspring of SUPP and DEF fathers had a significantly lower body weight than those of CTRL fed fathers. Moreover, hepatic trigylcerides and cholesterol were elevated 3-fold in adult female offspring of SUPP fathers. Weanling offspring of the same fathers displayed altered expression of several key lipid-metabolism genes. Hundreds of differentially methylated regions were identified in the paternal sperm in response to DEF and SUPP diets. Aside from a few genes including Igf2, there was a striking lack of overlap between these genes differentially methylated in sperm and differentially expressed in offspring.

Conclusions

In this animal model, modulation of paternal B vitamin intake prior to mating alters offspring weight gain, lipid metabolism and tumor growth in a sex-specific fashion. These results highlight the need to better define how paternal nutrition affects the health of offspring.     

Length‐weight relationships for five Clupeiformes species from the Persian Gulf and Oman Sea

Length‐weight relationships (LWRs) were determined for five Clupeiformes species representing three families collected from the Persian Gulf and Oman Sea. These are the first references on length‐weight relationships for two of these species (Ilisha megaloptera and Sardinella sindensis). A new maximum length record was obtained for one species (Ilisha melastoma).     

Length‐weight and length‐length relationships of the genus Alosa (Clupeoidei: Clupeiformes: Clupeidae) along the southern Caspian Sea coast

Length–weight (LWR) and length–length (LLR) relationships were estimated for four shad species of the genus Alosa, reported from along the southern Caspian Sea coast, north of Iran in a study from March 2014. Two of these species are endemic to the Caspian Sea. The length–weight parameter b for these species ranged from 2.99 to 3.24, with regression coefficients (r²) ranging from 0.91 to 0.99. All LLRs were highly significant (r² > 0.96).     

Enhancing Proper Sitting Position Using a New sEMG Protocol, The “Minimax” Procedure, With Boolean Logic

The modification of posture in children using sEMG is a new area that offers much potential to aid disabled children regain function. This article describes a new protocol, the minimax procedure, to aid children regain motor function in sitting. The protocol uses selective reinforcement to encourage recruiting/relaxing target sites (gluteus medius/maximus) in a predetermined way so as to encourage good form in sitting. Children often are unaware how to make changes in posture, and when they do succeed the progress is so slow that sustaining motivation is a challenge. This paper describes a procedure that helps the child recognize when they have achieved the correct posture, immediately rewards them for doing so, and generates data using Boolean operations to numerically substantiate the clinically observed changes in posture.     

Is Sudden Infant Death Syndrome Associated with Helicobacter pylori Infection in Children?

Helicobacter pylori infection has recently been implicated in the pathogenesis of sudden infant death syndrome (SIDS). We investigated this association. Twenty-five pairs of gastric and tracheal tissue specimens obtained from autopsies of 25 children with previous diagnoses of SIDS were available for this study. The presence of H. pylori organisms was evaluated by three different methods: histology (hematoxylin-eosin or Giemsa staining), immunohistochemistry, and nested polymerase chain reaction technique. We were unable to confirm the presence of H. pylori organisms by the first two methods. H. pylori DNA was identified by nested polymerase chain reaction in six different tissue specimens (stomach, 4; trachea, 2). In no case was H. pylori DNA detected in both tissues. We concluded that H. pylori infection is most likely not associated with SIDS.