Synthesis and structure-activity relationship of novel RXR antagonists: orally active anti-diabetic and anti-obesity agents

A series of diazepinylbenzoic acid derivatives were synthesized and tested in the inhibition assay of the transactivation of RXR. Oral treatment of cyano derivatives (16f) was found to show anti-diabetic and anti-obesity effects in KK-A(y) mice.     

Synthesis and structure-activity relationship of RXR antagonists based on the diazepinylbenzoic acid structure

Synthesis and structure-activity relationship of RXR antagonists employing a diazepinylbenzoic acid scaffold are described. Of those antagonists, sulfonamide derivatives (6v and 6w) reveal a high antagonistic activity and good pharmacokinetic properties.     

Plural light chains in a single plasma cell of a monoclonal gammopathy undetermined significance case: An ultrastructural study

A 44-year-old man was found to have M-proteins of IgG consisting of kappa- and lambda-chains in serum without lymphadenopathy or splenomegaly. The serum concentrations of IgG, IgA and IgM were within normal limits. Bone marrow examination showed normal cellular marrow containing 6.3% of plasma cells with no abnormal features. No chromosomal abnormality was observed at all. The patient was diagnosed as having monoclonal gammopathy of undetermined significance. The bone marrow plasma cells possessed free kappa- and lambda-chains in Golgi apparatus, rough endoplasmic reticula and cytoplasmic matrices. Plural light chains were simultaneously produced with the same heavy chain in a plasma cell by immunoelectron microscopy. This is the first report in the world of a monoclonal gammopathy of undetermined significance producing plural light chains with the same heavy chain.     

Characterization of yeastolate fractions that promote insect cell growth and recombinant protein production

Yeastolate is effective in promoting growth of insect cell and enhancing production of recombinant protein, thus it is a key component in formulating serum-free medium for insect cell culture. However, yeastolate is a complex mixture and identification of the constituents responsible for cell growth promotion has not yet been achieved. This study used sequential ethanol precipitation to fractionate yeastolate ultrafiltrate (YUF) into six fractions (F1–F6). Fractions were characterized and evaluated for their growth promoting activities. Fraction F1 was obtained by 65% ethanol precipitation. When supplemented to IPL-41 medium at a concentration of 1 g L⁻¹, fraction F1 showed 71% Sf-9 cell growth improvement and 22% β-galactosidase production enhancement over YUF (at 1 g L⁻¹ in IPL-41 medium). However, the superiority of F1 over YUF on promoting cell growth gradually diminished as its concentration in IPL-41 medium increased. At 4 g L⁻¹, the relative activity of F1 was 93% whereas YUF was 100% at the same concentration. At 1 g L⁻¹, four other fractions (F2–F5) precipitated with higher ethanol concentrations and F6, the final supernatant, showed growth promoting activities ranging from 32 to 80% as compared to YUF (100%). Interestingly, a synergistic effect on promoting cell growth was observed when F6 was supplemented in IPL-41 medium in presence of high concentrations of F1 (>3 g L⁻¹). The results suggest that ethanol precipitation was a practical method to fractionate growth-promoting components from YUF, but more than one components contributed to the optimum growth of Sf-9 cells. Further fractionation, isolation and identification of individual active components would be needed to better understand the role of these components on the cell metabolism.     

Comparative analysis of methods to determine DNA methylation levels of a tumor-related microRNA gene

Quantifying levels of DNA methylation in tumors is a useful approach for the identification of potential tumor suppressors and to find biomarkers that can be used as prognostic or therapeutic indicators. In the current study, we compared three methods commonly used for quantifying DNA methylation—bisulfite pyrosequencing, quantitative methylation-specific PCR (Q-MSP), and MethyLight—by focusing on the CpG island of the gene encoding the microRNA-34b and microRNA-34c (miR-34b/c); aberrant regulation of this miR is associated with various human malignancies, including gastric cancer. Standard curve analysis using control DNA samples demonstrated the highest quantitative accuracy in Q-MSP analysis. We also carried out methylation analysis using gastric mucosa specimens obtained from gastric cancer patients. We found a high correlation between methylation levels determined by Q-MSP and those determined by MethyLight (R² = 0.952), whereas the results of bisulfite pyrosequencing and the other two methods were less well correlated (R² = 0.864 and R² = 0.804 for Q-MSP and MethyLight, respectively). This may reflect possible PCR bias in the pyrosequencing technique, which we show can be corrected for by applying a cubic approximate equation to the original data. Thus, although results obtained by the different DNA methylation analysis techniques are largely comparable, an appropriate correction may be necessary for stringent comparison.     

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.     

Iron isotope fractionation during microbial dissimilatory iron oxide reduction in simulated Archaean seawater

The largest Fe isotope excursion yet measured in marine sedimentary rocks occurs in shales, carbonates, and banded iron formations of Neoarchaean and Paleoproterozoic age. The results of field and laboratory studies suggest a potential role for microbial dissimilatory iron reduction (DIR) in producing this excursion. However, most experimental studies of Fe isotope fractionation during DIR have been conducted in simple geochemical systems, using pure Fe(III) oxide substrates that are not direct analogues to phases likely to have been present in Precambrian marine environments. In this study, Fe isotope fractionation was investigated during microbial reduction of an amorphous Fe(III) oxide-silica coprecipitate in anoxic, high-silica, low-sulphate artificial Archaean seawater at 30 °C to determine if such conditions alter the extent of reduction or isotopic fractionations relative to those observed in simple systems. The Fe(III)-Si coprecipitate was highly reducible (c. 80% reduction) in the presence of excess acetate. The coprecipitate did not undergo phase conversion (e.g. to green rust, magnetite or siderite) during reduction. Iron isotope fractionations suggest that rapid and near-complete isotope exchange took place among all Fe(II) and Fe(III) components, in contrast to previous work on goethite and hematite, where exchange was limited to the outer few atom layers of the substrate. Large quantities of low-δ(56)Fe Fe(II) (aqueous and solid phase) were produced during reduction of the Fe(III)-Si coprecipitate. These findings shed new light on DIR as a mechanism for producing Fe isotope variations observed in Neoarchaean and Paleoproterozoic marine sedimentary rocks.     

A transmembrane glycoprotein, gp38, is a novel marker for immature hepatic progenitor cells in fetal mouse livers

Previously, we clarified the surface antigen profiles of hepatic progenitor cells (HPCs) in fetal liver tissue as the CD49f(+)CD45(-)Thy1(-) cell fraction. However, these cells were a heterogeneous cell population containing various stages of differentiation. This study aimed to detect more immature HPCs, using a novel surface antigen, gp38. After the collagenase digestion of fetal livers harvested from E13.5 to E18.5 fetal mice, HPCs were obtained and divided into two subpopulations using flow cytometry: gp38-positive HPCs, and gp38-negative HPCs. Both types of HPCs were characterized by immunocytochemistry and RT-PCR. The proliferative activity was compared by BrdU incorporation and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTS) assay. Furthermore, the comprehensive gene expression was investigated by DNA microarray. Both types of HPCs expressed alpha-fetoprotein. However, the gp38-positive HPCs derived from E13.5 fetal livers did not express albumin or cytokeratin 19, while the gp38-negative HPCs did. DNA microarray revealed that some genes related to the Wnt signal pathway were up-regulated in the gp38-positive HPCs. Furthermore, Wnt3a had a proliferative effect on the gp38-positive HPCs. In conclusion, the gp38-positive HPCs derived from fetal liver tissue until E13.5 could therefore be candidates for hepatic stem cells in the fetal liver.     

Photochemical stability of lipoic acid and its impact on skin ageing

It is well known that α-lipoic acid (LA) functions as an essential co-factor of the mitochondrial multi-enzyme complex and thus plays an important role in energy metabolism. Currently, it is attracting attention as a nutritional supplement because of its unique antioxidant properties and broad spectra of cellular functions. Skin protection from photodamage and ageing is one of the functional applications of LA. Medical and cosmetic application has been widely realized in the world. However, LA has a unique structure bearing a distorted five membered 1, 2-dithiolane ring, making it quite vulnerable to UV radiation. The present article briefly reviews skin ageing from the viewpoint of oxidative stress and sun exposure and analyses the photochemical properties of LA. It also discusses the effect of LA to cellular signalling and its adequate applications to treat skin ageing caused by oxidation. Data presented in this review suggest that LA is a powerful anti-ageing agent under the appropriate usage.