Search

This study depicts the 'click' construction of a water-soluble galactosyl rhodamine that can selectively probe mercury ions internalized by hepatoma cells over other cancer cells. [ABSTRACT FROM AUTHOR]

BACKGROUND In the present study, we describe a procedure to cryopreserve the postnatal members of the Leydig cell lineage, including progenitor (PLC), immature (ILC) and adult (ALC) Leydig cells from, respectively 21-, 35- and 90-day-old rats. METHODS The cells were resuspended in a culture medium supplemented with 1% bovine serum albumin (Dulbeccos Modified Eagles Medium [DMEM]/F12) to a final concentration of 2 × 106cells/ml and the effects of varying concentrations of dimethylsulfoxide (DMSO) (5, 10, 15 or 20%) were assessed after freezing at −70°C and then storing in liquid nitrogen. After 12 months of frozen storage, these cells were thawed rapidly at 37°C and Trypan Blue exclusion staining and attachment to culture dishes were assessed as measures of viability. RESULTS The trypan blue exclusion and attachment rates for Leydig cell stages were around 85% in the presence of 15% DMSO. After frozen storage, Leydig cell steroidogenic capacity in response to a range of LH doses, (0.01–100 ng/ml) was unchanged compared with freshly isolated control cells. Furthermore, the steady-state mRNA levels for Leydig cell specific transcripts were maintained. CONCLUSIONS This study demonstrates that purified rat Leydig cells at a range of developmental stages can be frozen and that the cryopreserved cells retain normal function. [ABSTRACT FROM AUTHOR]

Fluorogenic supramolecular complexes formed between tubular-shaped pyrenyl-β-cyclodextrins and glyco-rhodamine are determined to respond to a selective lectin with 'turn-on' fluorescence with excellent selectivity over a range of competing species. [ABSTRACT FROM AUTHOR]

Diabetic nephropathy (DN) is characterized by unclear pathogenesis. Recent medical data shows that the incidence of DN rises year by year. Rhein is the main compositions of rhubarb, a traditional Chinese medicinal plant, which plays an active role in kidney protection. The prophylaxis and phytotherapeutic effects of rhein are due to its anti-inflammatory and antifibrosis properties. Here, we shed light on the renal protective role of rhein in diabetes mellitus (DM) with a particular focus on the molecular basis of this effect. [ABSTRACT FROM AUTHOR]

The synthesis of diversely functionalized carbohydrate building blocks is of great interest towards the generation of new carbohydrate mimetics. Glycoaminoxy acids are recently developed glycoamino acid analogues with both an aminoxy and a carboxyl group connected to the sugar scaffold. These molecules could be readily used for the synthesis of various glycoconjugates through N-oxy amide or oxime bond, thus providing a potent tool for the design of novel functional carbohydrate mimetics. Here, the efficient synthesis of 2,6-functionalized pyranoid glycoaminoxy acid from commercially available methyl glucopyranoside is reported. The subsequent assembly of this glycoaminoxy acid building unit via N-acylation led successfully to the novel 2,6-linked oligosaccharide mimetics. [ABSTRACT FROM AUTHOR]

Exposures to di-(2-ethylhexyl) phthalate (DEHP) have been shown to be associated with decreased adult testosterone (T) levels and increased Leydig cell numbers. As yet, little is known about DEHP effects in utero on fetal Leydig cells (FLC). The present study investigated effects of DEHP on FLC function. Pregnant Long-Evans female rats received vehicle (corn oil) or DEHP at 10, 100, or 750 mg/kg by oral gavage from gestational day (GD)2-20. At GD21, T production, FLC numbers and distribution, and testicular gene expression were examined. The percentage of FLC clusters containing 6-30 cells increased in all treatment groups, with 29 ± 2% in control vs. 37 ± 3, 35 ± 3, and 56 ± 4% in rats receiving 10, 100, and 750 mg/kg DEHP, respectively. In contrast, FLC numbers were 33% and 39% lower than control after exposures to 100 and 750 mg/kg DEHP, respectively. At these doses, mRNA levels of leukemia inhibitory factor (LIF) increased. LIF was found to -induce cell aggregation in FLCs in vitro, consistent with the hypothesis that DEHP induced FLC aggregation. Testicular T levels were doubled by the 10 mg/kg dose and halved at 750 mg/kg. The mRNA levels of IGF-1 and c-Kit ligand (KITL) were induced by 10mg/kg DEHP. These results, taken together, indicate that fetal exposures to DEHP have effects on FIC number, distribution, and most importantly, steroidogenic capacity and suggest that abnormal expressions of IGF1, KITL, and LIF genes may contribute to the reproductive toxicity of phthalates. [ABSTRACT FROM AUTHOR]

A tetrameric N-acetyl galactosaminyl (GalNAc) peptidomimetic was constructed by N-acetylation of repeating proline-based hydroxamic acid units, followed by a convergent 'click chemistry' coupling. This novel glycopeptidomimetic was determined to effectively antagonize the interaction between a transmembrane hepatic lectin and GalNAc on the cellular level. [ABSTRACT FROM AUTHOR]

Here, we describe a novel "switch-on" biosensor based on quinonyl glycosides functionalized quantum dots (QDs) for the specific targeting and imaging of transmembrane glycoprotein receptors on the surface of cancer cells. The design of the quinonyl glycosides lies in that the quinone moiety serves as a quencher of QDs and the glycoside moiety as a biospecific ligand for targeting a receptor. We observed that the quenched photoluminescence of the quinone glycosides functionalized QDs could be significantly recovered by a specific lectin that selectively binds to the glycosides clustering the QDs but was not affected by a panel of nonspecific lectins. Moreover, we determined that quinonyl galactoside functionalized QDs could optically image the asialoglycoprotein receptors of a hepatoma cell line in a target-specific manner. This system might provide new insights into the fabrication of photoluminogenic biosensors for the analysis of the universal ligand-receptor recognitions in nature. [ABSTRACT FROM AUTHOR]

Transition metal-free cascade reactions of alkynols with imines have been achieved using potassium tert-butoxide as catalyst Switching the reaction solvent gives two kinds of products in good yield: isoquinolin-1(2H)-one derivatives and dihydroisobenzofuran derivatives. This approach was used to generate the natural product 8-oxypseudopalrnatine in a two-step procedure from commercially available starting materials. Additionally, multicomponent reactions of alkynols, aldehydes, and amines were also successfully achieved to afford isoquinolin-1(2H)-one derivatives. [ABSTRACT FROM AUTHOR]

Development of sugar-based fluorescence (FL) chemo-probes is of much interest since sugars are biocompatible, water-soluble and structurally rigid natural starting materials. We report here that fluorescent glycoligands with two triazolyl coumarin moieties installed onto the different positions of an identical glucosyl nucleus exert completely reversed optical response to a metal ion. C3,4-, C2,3- and C4,6-di-substituted coumarin glucosides synthesized by a click reaction similarly showed a selective FL variation in the presence of silver (I) among a range of metal cations in an aqueous solution. However, the variation was determined to be converse: the FL of the C3,4-ligand was quenched whereas that of the C2,3/ C4,6-ligand tangibly enhanced. FL andNMRtitrations suggested that this divergence was due to the distinct complexation modes of the conformationally constrained ligands with the ion. The optimal motifs of the ligand-ion complexation were predicted by a computational simulation. Finally, the C2,3-ligand was determined to be of low cytotoxicity and applicable in the FL imaging of silver ions internalized by live cells. [ABSTRACT FROM AUTHOR]

Intercellular ligand-receptor recognitions are crucial natural interactions that initiate a number of biological and pathological events. We present here the simple construction of a unique class of biomimetic interfaces based on a graphene-mediated self-assembly of glycosyl anthraquinones to a screen-printed electrode for the detection of transmembrane glycoprotein receptors expressed on a hepatoma cell line. We show that an electroactive interface confined with densely clustered galactosyl ligands is able to ingeniously recognize the asialoglycoprotein receptors on live Hep-G2 cells employing simple electrochemical techniques. The only facility used is a personal laptop in connection with a cheap and portable electrochemical workstation. [ABSTRACT FROM AUTHOR]

Background: Pregnant women and infants have significant exposures to the most commonly used plasticizer di-(2-ethylhexyl) phthalate (DEHP). Objectives: This study was designed to evaluate the effects of DEHP exposure on growth and lung maturation in rats and determine if DEHP regulation of 11β-hydroxysteroid dehydrogenase type 1 gene ( Hsd11b1) expression in the lung tissue plays a role in its effects on lung maturation. Method: Pregnant Sprague-Dawley rats were treated from gestational day 12 to postnatal day (PND) 21 with DEHP orally at dosages of 0, 10, 100 or 750 mg/kg/day, respectively (n=8 for each group). Two rat pups (one male and one female) from each litter were sacrificed at PND 1 and 21. Body weight was measured and the lung was processed for histology and calculation of lung interstitial tissue proportion as well as real-time PCR determination of the expressions of Hsd11b1, surfactant associated protein-A1 gene ( Sftpa1) and B gene ( Sftpb). Results: The perinatal DEHP exposure led to a dose dependent intrauterine and postnatal growth restriction (P<0.001). High dose DEHP (750 mg/kg/day) exposure led to decreased gas-exchange space as evidenced by increased lung interstitial tissue proportion (P<0.001), but did not cause significant changes in Hsd11b1, Sftpa1 or Sftpb gene expression in the rat lung at PND 1. The DEHP-induced change in lung histology remained significant at PND 21 with improvement despite continual exposure to DEHP. Conclusion: Perinatal DEHP exposure leads to growth restriction and delayed lung maturation in newborn rats. [ABSTRACT FROM AUTHOR]

Background: Lymphangiogenesis has become a new research frontier in tumor metastasis since the discovery of reliable lymphatic markers that have allowed observation and isolation of lymphatic endothelium. Cyclooxygenase-2 (COX-2) has been reported to be involved in the critical steps in carcinogenesis. However, possible role of COX-2 in lymphangiogenesis and lymphatic metastasis is still poorly understood. In present study, we aimed to investigate the relationship between vascular endothelial growth factor-C (VEGF-C) and COX-2 in human breast cancer, and correlations with lymphangiogenesis and prognosis. Methods: Tissue samples of primary tumors from 70 patients undergoing intentionally curative surgical resections for breast cancer were immunohistochemically examined for VEGF-C, COX-2, and D2-40 expressions. The association between COX-2 and VEGF-C expressions and clinicopathological parameters as well as prognosis were analysised. To demonstrate the presence of proliferating lymphatic endothelial cells, 10 random cases with high LVD counts were selected for D2-40/Ki-67 double immunostaining. Results: A significant correlation was found between the expression of VEGF-C and COX-2 (r = 0.529, P < 0.001), and both elevated VEGF-C expression and elevated COX-2 expression were associated with higher lymph vessel density (LVD), lymph node metastasis and D2-40 positive lymphatic invasion (LVI) as well as worse disease free survival (DFS) and overall survival (OS) in a univariate analysis. In the double immunostain for the lymph vessel marker D2-40 and the proliferation marker Ki-67, the results confirmed Ki-67-positive nuclei in a proportion of lymph vessel endothelial cells. Conclusion: There is indeed lymphangiogenesis in breast cancer, the most compelling evidence being the presence of proliferating lymphatic endothelial cells. VEGF-C and COX-2 are coexpressed and significantly associated with lymphangiogenesis and prognosis in invasive breast cancer. Suggesting COX-2 may up-regulate VEGF-C expression and thus promote lymph node metastasis via lymphangiogenesis pathway in human breast cancer. [ABSTRACT FROM AUTHOR]