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The eye is a complex organ with highly specialized constituent tissues derived from different primordial cell lineages. The retina, for example, develops from neuroectoderm via the optic vesicle, the corneal epithelium is descended from surface ectoderm, while the iris and collagen-rich stroma of the cornea have a neural crest origin. Recent work with pluripotent stem cells in culture has revealed a previously under-appreciated level of intrinsic cellular self-organization, with a focus on the retina and retinal cells. Moreover, we and others have demonstrated the in vitro induction of a corneal epithelial cell phenotype from pluripotent stem cells. These studies, however, have a single, tissue-specific focus and fail to reflect the complexity of whole eye development. Here we demonstrate the generation from human induced pluripotent stem cells of a self-formed ectodermal autonomous multi-zone (SEAM) of ocular cells. In some respects the concentric SEAM mimics whole-eye development because cell location within different zones is indicative of lineage, spanning the ocular surface ectoderm, lens, neuro-retina, and retinal pigment epithelium. It thus represents a promising resource for new and ongoing studies of ocular morphogenesis. The approach also has translational potential and to illustrate this we show that cells isolated from the ocular surface ectodermal zone of the SEAM can be sorted and expanded ex vivo to form a corneal epithelium that recovers function in an experimentally induced animal model of corneal blindness.

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(-)-Epigallocatechin gallate (EGCg) is the major component of green tea and is known to show strong biological activity, although it can be easily oxidized under physiological conditions. In this study, we indicate that EGCg is stable in human serum and that human serum albumin (HSA) stabilizes EGCg under aerobic condition. Although EGCg is usually decomposed within 1 h in aqueous solution at neutral pH, EGCg in serum and phosphate buffer (pH 7.4) containing HSA was stable over 1 h, even at neutral and slightly alkaline pH. Under these conditions, EGCg binds to HSA non-covalently. The sulfhydryl group acts as an antioxidant for EGCg oxidation. Incubation of EGCg with HSA is accompanied by the oxidation of a free sulfhydryl group in HSA. These results suggest that the antioxidant property and the binding capacity of HSA contribute to the stabilization of EGCg in human serum.

The present study was conducted to assess the role of transforming growth factor ␤ (TGF-␤) and activin(s) in the regulation of the mass of the liver. To this end, we eliminated TGF-␤ or activin signaling in intact rat liver by adenovirus-mediated transfer of the gene encoding truncated type II TGF-␤ receptor (AdextTR) or truncated type II activin receptor (AdextAR). In intact rat liver that received a single application of either AdextTR or AdextAR via the portal vein, DNA synthesis as assessed by bromodeoxy uridine (BrdU) labeling was induced. In AdextTR-or AdextARtreated rats, nuclear labeling was significantly higher than that in AdexLacZ, adenovirus vector encoding Escherichia coli ␤-galactosidase gene, or saline-treated rats at 3, 5, 7, and 9 days of infusion. The peak of the BrdU labeling was observed after 7 days of infusion and the labeling decreased The ratio of liver mass and body weight is kept within a narrow range under normal conditions, and it is generally thought that all cells except a tiny fraction (0.01% to 0.05%) are essentially in a state of growth arrest or G 0 phase in normal liver. Hepatocytes are induced to enter the cell cycle by cell loss or functional inadequacy, such as partial hepatectomy, infection, toxic injury and metabolic imbalances. 1 When the liver mass is reduced, for example, by partial hepatectomy, DNA synthesis begins and continues until the original liver mass is restored within a week. The liver mass reaches the optimal body size level, and liver regeneration stops. 2 This implies the existence of a regulatory mechanism for the maintenance of constant liver mass.Members of the transforming growth factor ␤ (TGF-␤) superfamily, such as TGF-␤ and activin, elicit diverse effects on cellular growth and differentiation and modulate various cellular functions. 3,4 Activin A is an autocrine inhibitor of the initiation of cell growth in parenchymal cells of the liver, 5 and blockade of the activin action by administration of follistatin, an activin antagonist, accelerates liver regeneration after partial hepatectomy. 6 Furthermore, a recent study in our laboratory showed that infusion of follistatin into the portal vein induced DNA synthesis even in intact rat liver. 2 Assuming that follistatin exerted its action solely by blocking the effect of activin, these results raise an interesting possibility that activin A maintains constant liver mass by tonically blocking cell growth in intact liver. Interestingly, after follistatin increased liver mass, apoptosis took place and the liver mass returned to the normal value thereafter. 2 This reduction of the liver mass was associated with a marked increase in the expression of TGF-␤. 2 It is likely that TGF-␤ may have induced apoptosis, and thereby reduced the liver mass. Collectively, these results suggest that TGF-␤, which inhibits proliferation of hepatocytes as an autocrine as well as a paracrine factor, 7-9 acts as a compensatory mechanism to maintain constant liver mass. However, whether TGF-␤ is crucially important in the regula...

The structure of the thermotropic cubic phases of 4 ¾ -n -alkoxy-3 ¾ -nitrobiphenyl-4-carboxylic acids (ANBC-n , where n indicates the number of carbon atoms in the alkoxy group) was studied by X-ray di V raction. For the homologues with n= 15, 16, 17, and 18, the cubic phase was of an Ia 3 d type, whereas the homologues with n = 19, 20, and 21 exhibited an Im 3 m cubic structure; for these seven homologues the same type of cubic structure was observed both on heating and cooling. Further lengthening of the alkoxy chain to n= 22 and 26, however, gave two types of cubic structure in the cubic phase region on heating, one with Im 3 m symmetry in the low temperature region and the other with Ia 3 d symmetry in the high temperature region. On cooling, the two homologues exhibited the Ia 3 d cubic structure only. This is the rst example in the cubic phase region of a series of homologues containing two types of structure, dependent on temperature and n . Such a complicated phase diagram in the cubic region is clearly understood qualitatively in terms of Gibbs free energy-temperature diagrams. The dependence of structural parameters such as the cubic lattice constant on the alkoxy chain length n are also presented and discussed.

Protein tyrosine phosphatases (PTPs), together with protein tyrosine kinases (PTKs), are involved in the regulation of cell activation, growth, and differentiation. To further elucidate the fine tuning of cell growth and differentiation through tyrosine phosphorylation, we tried to isolate mouse receptor-type PTP (RPTP) cDNA clones by screening mouse brain cDNA libraries with mouse CD45 PTP domain probes under reduced-stringency conditions. Characterization of isolated cDNA clones for RPTP showed that the cytoplasmic region contains two tandem repeats of PTP domain of about 230 amino acids with intrinsic phosphatase activity. The extracellular region was composed of immunoglobulin (Ig)-like domains and fibronectin type III (FN-III)-like domains. The gene was highly homologous to human PTP delta (HPTP delta) and thus was named MPTP delta (murine counterpart of HPTP delta). The MPTP delta gene appeared to generate at least three species of mRNA, which differ in the composition of the extracellular domain: type A, one Ig-like and four FN-III-like domains; type B, one Ig-like and eight FN-III-like domains; and type C, three Ig-like and eight FN-III-like domains. Interestingly, the 5' untranslated region and the leader peptide of types A and B were completely different from those of type C. Northern (RNA) blot analysis demonstrated that brain, kidney, and heart cells express three mRNA species of about 7 kb. Antibody directed against part of the extracellular domain of type A MPTP delta recognized a 210-kDa protein in brain and kidney lysates. In situ hybridization of brain samples revealed that MPTP delta mRNA is present in the hippocampus, thalamic reticular nucleus, and piriform cortex, where some Src family PTKs have been also demonstrated to exist. Although MPTP delta mRNA was not detected in lymphoid tissues, all of the pre-B-cell lines tested and one of three B-cell lines tested expressed MPTP delta mRNA, whereas antibody-producing B-cell hybridomas and T-cell and macrophage lines did not. Finally, the MPTP delta locus was tightly linked to the brown (b) locus on mouse chromosome 4.

The cholinergic structures in the forebrain of the rat were studied immunohistochemically with a monoclonal antibody to choline acetyltransferase (ChAT) which has proven to be particularly suited to reveal the trajectory of ChAT-positive fibers and their terminations. The habenulo-interpeduncular tract contained the most distinctly ChAT- positive fibers. Here, ChAT-positivity was demonstrated in the perikarya, fibers and terminal field. From the basal forebrain, ChAT- positive fiber bundles could be followed rostrally to the olfactory bulb, dorsomedially to the neocortex and hippocampus, and dorsocaudally to the hippocampus. Terminations of ChAT-positive fibers in these regions were either boutons terminaux (in the interpeduncular nucleus), finely granular (in the hippocampus) or a network of varicose fibers (in the olfactory bulb and neocortex). Cholinergic terminal fields were also demonstrated in the following regions: the nucleus of the lateral olfactory tract, the olfactory tubercle, the pyriform cortex, the lateral nucleus and part of the basal nucleus of the amygdala, the caudate-putamen, the nucleus accumbens, some thalamic nuclei, and the suprachiasmatic nucleus of the hypothalamus. In most of these regions, ChAT-positivity appeared as either fine granules or a meshwork of varicose fibers.