Synthesis and evaluation of bibenzyl glycosides as potent tyrosinase inhibitors

Bibenzyl glycosides 1-6 were synthesized from 2,4-dihydoxybenzaldehyde and xylose, glucose, cellobiose or maltose. The key steps in the synthesis were the Wittig reaction and trichloroacetimidate glycosylation. Tests for tyrosinase inhibitory activity showed that all were significantly active, indicating that they are unique hydrophilic tyrosinase inhibitors. Bibenzyl xyloside 2 is a particularly potent inhibitor (IC(50) = 0.43 μM, 17 times higher than that of kojic acid). These results suggest that the hydrophilic cavity of tyrosinase might accommodate the bulky carbohydrate on the bibenzyl scaffold.

Measurement of health-related quality of life in patients with chronic kidney disease in Japan with EuroQol (EQ-5D)

BACKGROUND

Chronic kidney disease (CKD) is a health-related quality-of-life (HRQOL) deteriorating disease which is not only a public health but also a socioeconomic problem. Interest in developing cost-effective interventions to control CKD has increased. The aim of this study was to measure HRQOL in terms of quality-adjustment weights for cost-effectiveness analysis using EQ-5D in patients with CKD. The relationships between the measured HRQOL and clinical indices/complications were also analyzed.

METHODS

EQ-5D, a generic preference-based instrument, was administered to 569 CKD outpatients at Tsukuba University Hospital between November and December 2008. The response rate was 94.4% (537/569). Data on sex, age, creatinine, hemoglobin, serum albumin and eGFR were obtained from the patients' records. Data on the presence of complications such as hypertension, diabetes, and history of cardiovascular disease (CVD) were also retrieved.

RESULTS

Measured quality-adjustment weights by the CKD stage were 0.940 (95% CI 0.915-0.965), 0.918 (0.896-0.940), 0.883 (0.857-0.909), 0.839 (0.794-0.884), and 0.798 (0.757-0.839) for stages 1-5, respectively. The decrease in weight was significant by ANOVA (P < 0.0001), and the weight for all stages was 0.885 (0.871-0.898). There was a positive relationship between hemoglobin/serum albumin and the weight. The presence of hypertension lowered the weight from 0.910 (0.885-0.936) to 0.874 (0.858-0.891), diabetes from 0.901 (0.886-0.917) to 0.840 (0.811-0.869), and CVD from 0.892 (0.878-0.906) to 0.783 (0.718-0.848).

CONCLUSIONS

HRQOL decreases with progression of CKD stage and/or presence of anemia, undernutrition, hypertension, diabetes, or history of CVD.

Molecular design of potent tyrosinase inhibitors having the bibenzyl skeleton

In order to develop water soluble tyrosinase inhibitors, bibenzyl xyloside 1 isolated from Chlorophytum arundinaceum (liliaceae), and its derivatives 2 and 3 were synthesized by using Wittig reaction and trichloroimidate glycosylation procedure as key steps. Xylosides 1-3 showed potent tyrosinase inhibitory activity with IC(50)s of 1.6, 0.43, and 0.73 microM, respectively, although each NMR data of synthetic bibenzyls was not identical to that of naturally occurring xyloside 1.

In Situ Generation of Oxo−sulfidobis(dithiolene)tungsten(VI) Complexes: Active-Site Models for the Aldehyde Ferredoxin Oxidoreductase Family of Tungsten Enzymes

Oxo-sulfidobis(dithiolene)tungsten(VI) complexes were prepared in situ by the reaction of oxobis(dithiolene)tungsten(V) precursors with hydrosulfide (SH-). The complexes, characterized by UV-vis, electrospray ionization mass spectrometry, IR, and resonance Raman spectroscopies, model the proposed coordination environment and observed hydrolytic reactions of members of the aldehyde ferredoxin oxidoreductase family of tungsten enzymes.

Hypoxic enhancement of type IV collagen secretion accelerates adipose conversion of 3T3-L1 fibroblasts

Hypoxic modulation of collagen metabolism appears to be related to pathogenesis of many diseases such as fibrosis of connective tissue after injury and scleroderma. Since most of our understanding of how procollagen assembles within the cell has come from studies on cells cultured under normoxia, it may not be helpful for the etiology of the diseases observed in peripheral tissues under hypoxic conditions. As an experimental model for the hypoxic modulation of collagen metabolism, we cultured 3T3-L1 fibroblasts under low partial oxygen pressure and found that hypoxia enhances secretion of type IV collagen 10-fold and accelerates adipose conversion of the cells. The enhanced secretion of type IV collagen was not accompanied by an appreciable increase of alpha1(IV) and alpha2(IV) mRNAs. Prolyl 4-hydroxylase alpha increased only 3-fold under hypoxia. We suggest that hypoxia creates an environment of prolyl 4-hydroxylase alpha(2)beta(2) tetramers favorable for the folding of type IV procollagen which has many interruptions of the Gly-Xaa-Yaa repeat.

Trafficking of human ADAM 12-L: retention in the trans-Golgi network

We have investigated the trafficking of the membrane-anchored form of human ADAM 12 (ADAM 12-L) fused to a green fluorescence protein tag. Subcellular localization of the protein in transiently transfected cells was determined by fluorescence microscopy and trypsin sensitivity. Full-length ADAM 12-L was retained in a perinuclear compartment, which was shown to be the trans-Golgi network. In contrast, ADAM 12-L lacking the cytoplasmic domain reached the cell surface. Based on analysis of deletions and mutations of the cytoplasmic tail of ADAM 12-L, the retention signal is comprised of both the cytoplasmic and transmembrane domains, but not the Src homology 3 domain (SH3) binding sites. These results raise the possibility that a trafficking checkpoint in the trans-Golgi network is one of the cellular mechanisms for regulation of ADAM 12-L function, by allowing a rapid release of ADAM 12-L to the cell surface under specific stimuli.