Three-dimensional image analysis of the hepatic restructuring process in chronic active hepatitis

OBJECTIVE: To elucidate the process of hepatic restructuring in the course of chronic hepatitis from a morphologic viewpoint. STUDY DESIGN: The three-dimensional (3-D) liver structure was investigated by computer-aided reconstruction in five cases (one autopsy and four surgical cases) of chronic active hepatitis (type C), including early to late stages of restructuring. RESULTS: Our 3-D reconstruction revealed the following. At an early stage, portal and periportal inflammation and fibrosis widened the portal tracts, giving rise to the formation of portal-to-portal and portal-to-hepatic venous connections, although most central veins were still located at an almost normal site in the hepatic lobules. In a middle stage, bridging fibrosis developed to create a network of interstitium where the central veins were rather decreased in number, with regenerative nodules multiplying in the parenchyma. At the late stage, the lobular structure was destroyed, and the parenchyma consisted uniformly of regenerative nodules, with remaining but rearranged lobules among them. CONCLUSION: The above changes of liver structure suggest that in cirrhogenesis from chronic hepatitis, a combination of nodular regeneration and formation of an interstitial network come to replace the normal lobular structure, hastening the development of liver cirrhosis.     

Microscale synthesis of dextran-based multivalent N-linked oligosaccharide probes

We developed a convenient method for the synthesis of dextran-based multivalent probes containing N-linked oligosaccharides which is efficient even in a small scale. Oligosaccharides were derivatized with succinic dihydrazide and dimethylamine borane under a mild acidic condition. The derivatized oligosaccharides were then conjugated in a good yield to periodate-oxidized dextran (500 kDa). Thus, the conjugates containing 120 to 140 oligosaccharide chains per dextran molecule were successfully synthesized. Their practical advantage was shown by the example that the asialofetuin oligosaccharide-dextran conjugate has much higher affinity to Ricinus communis agglutinin (RCA-I) than asialofetuin oligosaccharide itself or asialofetuin. The conjugates were further labeled with fluorescent reagent or biotinylation reagent containing a hydrazino group by the use of the unreacted aldehyde groups of the oxidized dextran, yielding probes with similar densities of fluorophores or biotin groups. Direct binding of the biotinylated asialofetuin oligosaccharide-dextran probe to RCA-I coated on the titer plate at a concentration of 50 ng/50 microl was easily detected using 50 fmol (as oligosaccharides) of the probe. The method for the synthesis of dextran-based oligosaccharide probes will facilitate the investigation of carbohydrate-mediated molecular interactions based on the native oligosaccharide structures.     

Highly divergent sequences of the pollen self-incompatibility (S) gene in class-I S haplotypes of Brassica campestris (syn. rapa) L

Self-incompatibility (SI) enables flowering plants to discriminate between self- and non-self-pollen. In Brassica, SI is controlled by the highly polymorphic S locus. The recently identified male determinant, termed SP11 or SCR, is thought to be the ligand of S receptor kinase, the female determinant. To examine functional and evolutionary properties of SP11, we cloned 14 alleles from class-I S haplotypes of Brassica campestris and carried out sequence analyses. The sequences of mature SP11 proteins are highly divergent, except for the presence of conserved cysteines. The phylogenetic trees suggest possible co-evolution of the genes encoding the male and female determinants.     

Flavonoid and benzophenone glycosides from Coleogyne ramosissima

A benzophenone glucoside and two flavonol glycosides were isolated together with 27 known polyphenols from the aerial parts of Coleogyne ramosissima, and their structures were elucidated by spectroscopic and chemical methods as iriflophenone 2-O-beta-glucopyranoside, isorhamnetin 3-O-2G-rhamnopyranosylrutinoside-7-O-alpha-rhamnopyranoside and limocitrin 3-O-rutinoside-7-O-beta-glucopyranoside, respectively.     

G-protein-coupled receptors and asthma endophenotypes: the cysteinyl leukotriene system in perspective

Genetic variation in specific G-protein coupled receptors (GPCRs) is associated with a spectrum of respiratory disease predispositions and drug response phenotypes. Although certain GPCR gene variants can be disease-causing through the expression of inactive, overactive, or constitutively active receptor proteins, many more GPCR gene variants confer risk for potentially deleterious endophenotypes. Endophenotypes are traits, such as bronchiole hyperactivity, atopy, and aspirin intolerant asthma, which have a strong genetic component and are risk factors for a variety of more complex outcomes that may include disease states. GPCR genes implicated in asthma endophenotypes include variants of the cysteinyl leukotriene receptors (CYSLTR1 and CYSLTR2), and prostaglandin D2 receptors (PTGDR and CRTH2), thromboxane A2 receptor (TBXA2R), beta2-adrenergic receptor (ADRB2), chemokine receptor 5 (CCR5), and the G protein-coupled receptor associated with asthma (GPRA). This review of the contribution of variability in these genes places the contribution of the cysteinyl leukotriene system to respiratory endophenotypes in perspective. The genetic variant(s) of receptors that are associated with endophenotypes are discussed in the context of the extent to which they contribute to a disease phenotype or altered drug efficacy.     

Acetylated YY1 regulates Otx2 expression in anterior neuroectoderm at two cis-sites 90 kb apart

The mouse homeobox gene Otx2 plays essential roles at each step and in every tissue during head development. We have previously identified a series of enhancers that are responsible for driving the Otx2 expression in these contexts. Among them the AN enhancer, existing 92 kb 5' upstream, directs Otx2 expression in anterior neuroectoderm (AN) at the headfold stage. Analysis of the enhancer mutant Otx2(DeltaAN/-) indicated that Otx2 expression under the control of this enhancer is essential to the development of AN. This study demonstrates that the AN enhancer is promoter-dependent and regulated by acetylated YY1. YY1 binds to both the AN enhancer and promoter region. YY1 is acetylated in the anterior head, and only acetylated YY1 can bind to the sequence in the enhancer. Moreover, YY1 binding to both of these two sites is essential to Otx2 expression in AN. These YY1 binding sites are highly conserved in AN enhancers in tetrapods, coelacanth and skate, suggesting that establishment of the YY1 regulation coincides with that of OTX2 function in AN development in an ancestral gnathostome.     

Studies on Isomerization of Sugars by Bacteria

An enzyme, which catalyzes the isomerization of d-glucose to d-fructose, has been found in a newly isolated bacterium which tentatively identified as Pacacolobacterum aerogenoides. The enzyme converts not only d-glucose but also d-mannose to d-fructose, and NAD and Mg⁺⁺ are required as cofactor for this isomerization. The properties of this enzyme were summarized as follows: (1) As a cofactor for the isomerization by this enzyme, NAD was absolutely necessary, whereas NADP, FMN and FAD were not. (2) The optimum pH was found to be at 7.5 and optinum temperature was at about 40°C. (3) The enzyme activity was markedly reduced by EDTA treatment and the reduced activity by EDTA was restored by the addition of Mg⁺⁺, Mn⁺⁺ or Co⁺⁺. (4) The enzyme activity was strongly inhibited by monoiodoacetate, p-chloromercuribenzoate, and Cu⁺⁺, however, the activity was recovered by adding cysteine or glutathione.     

Effect of environmental conditions on the α-glucosidase inhibitory activity of mulberry leaves

Mulberry leaves have been used as the sole food for silkworms in sericulture, and also as a traditional medicine for diabetes prevention. Mulberry leaf components, for example 1-deoxynojirimycin (1-DNJ), inhibit the activity of α-glucosidase and prevent increased blood glucose levels, and they are highly toxic to caterpillars other than silkworms. The α-glucosidase inhibitory activity of mulberry leaves changes with the season, but it is unknown which environmental conditions influence the α-glucosidase inhibitory activity. We investigated in this study the relationship between the α-glucosidase inhibitory activity and environmental conditions of temperature and photoperiod. The results demonstrate that low temperatures induced decreasing α-glucosidase inhibitory activity, while the induction of newly grown shoots by the scission of branches induced increasing α-glucosidase inhibitory activity. These results suggest that the α-glucosidase inhibitory activity was related to the defense mechanism of mulberry plants against insect herbivores.     

The effect of C3 transferase on human adipose-derived stem cells

Human adipose-derived stem cells (ASCs) are adult pluripotent stem cells, which have the ability to differentiate into fat, cartilage, bone, or nerves that can be applied in tissue engineering. On the other hand, the exoenzyme C3 transferase (C3) is a Rho inhibitor. Once in the cytosol, the cell-penetrating moiety is released, thereby allowing C3 transferase to freely diffuse intracellularly and inactivate RhoA, RhoB, and RhoC, but not related GTPases such as Cdc42 or Rac1. In this study, we investigated ASC cytoskeletal changes induced by the addition of C3 employing immunofluorescence staining, changes in alpha-smooth muscle actin (a-SMA) gene expression employing real-time RT-PCR, and the Rho-inhibitory effect employing the pull-down assay. C3 significantly reduced stress fiber disruption and a-SMA expression 24 h after its addition at a concentration of 1 μg/ml, and it also reduced the Rho activity level. While the correlation of the occurrence can be assumed, it requires further examination to verify it. C3 may be an effective inhibitor of intracellular signal transmission in ASC cytoskeletal control involving Rho.