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A large number of hydrophilic sponges were prepared by polymerisation of 2‐hydroxyethyl methacrylate in variable concentrations of water (60‐90% wt) in the initial monomer mixture. Concentration and type of crosslinking agents (ethylene dimethacrylate (EDMA) and hexamethylene dimethacrylate (HDMA)) and concentration of redox initiators were also changed. All sponges were examined in cross‐section by conventional and environmental scanning electron microscopy. Micrographs indicated that, in order to obtain sponges with characteristics appropriate for biomedical use (e.g. pores larger than 10 μm), the minimum water concentration was 75% wt with EDMA as a crosslinking agent, or 70% wt with HDMA, for contents of crosslinking agents and initiator less than 1% wt. Micrographs also showed that higher contents of crosslinking agents or initiator led to larger pores. In high concentrations of water, this effect was less evident. Microscopic details confirmed the crucial role of the phase separation during polymerisation.

BACKGROUND Vascular endothelial growth factor (VEGF) and its kinase insert domain receptor (KDR) play an important role in angiogenesis, and their gene expression patterns also suggest a close relationship with early pregnancy. However, limited information is available regarding the role of the VEGF system, especially its KDR receptor, in recurrent pregnancy loss (RPL). This study was conducted to investigate a genetic association between VEGF and its receptor gene (KDR) with idiopathic RPL. METHODS In this case-control study, 115 women who had experienced at least two consecutive spontaneous miscarriages (n= 62 women with two miscarriages, n= 53 with three or more) and 170 controls were included. A total of 14 tag single-nucleotide polymorphisms (SNPs) of VEGF and KDR were selected from the HapMap Web site and three functional SNPs [rs1570360 (-1154G/A) of VEGF; rs2305948 (V297I) and rs1870377 (Q472H) of the KDR gene] were genotyped using primer extension analysis. We further used multifactor dimensionality reduction analysis to evaluate gene-gene interactions. RESULTS One tag SNP (rs6838752) and the functional SNP (Q472H) of the KDR gene were in complete linkage and showed significant differences between patients and controls (P< 0.05). The frequencies of haplotypes of VEGF (A-T-G haplotype) and KDR (A-C-A-T-G haplotype) showed significant differences in patients versus controls (P< 0.05). All comparisons with controls remained significant when the subgroup of women with three or more miscarriages was analyzed. CONCLUSIONS VEGF and its receptor gene (KDR) are associated with idiopathic RPL. The VEGF/KDR system jointly contributes to recurrent miscarriage in Taiwanese Han women.

The combination at the interface between two chemically identical polymers was investigated by light and electron (scanning, transmission) microscopy. The polymers constitute elements of a new type of artificial cornea in which the peripheral skirt is made from spongy poly(2-hydroxyethyl methacrylate) (PHEMA) and the central optical zone from homogeneous, transparent PHEMA. Their two-phase combination along the boundary fulfill formally the requirements for an interpenetrating polymer network (IPN). The procedure for the manufacture of prosthesis was described in detail. Thin and ultrathin sections excised from the interface region were investigated using microscopic techniques. Light microscopy allowed the measurement of the diffusion path length of transparent PHEMA into sponge, which was approximately 0.5 mm. Transmission electron microscopy revealed a cellular-like morphology as well as larger segregated zones, which indicated network interpenetration on a molecular level and also a relatively poor miscibility of the two polymers despite their identical chemical structure. The latter was interpreted as a result of the submicroscopic restraints imposed by polymer I (sponge) upon polymer II. This study provides evidence that the interface combination of the prosthetic elements should be regarded as a gradient homo-IPN. This system offers a union between elements much stronger than those previously reported in artificial corneas.

The extracellular nuclease of Serratia marcescens is regulated in a complex fashion. Unlike most catabolic enzymes, it appears not to be substrate regulated. However we have shown it to be regulated by an SOS-like system in S. marcescens. Additionally nuclease expression is regulated in a growth-phase-dependent manner. In this work we demonstrate that growth-phase-dependent regulation is at the transcriptional level. The putative LexA-binding site which mediates SOS regulation is shown to act as an operator site in vivo. The boundaries of a minimal promoter, still regulated by growth phase and SOS regulation, are defined along with the transcriptional start site. However, a region upstream of the nuclease promoter is shown to enhance significantly the expression of nuclease.