Biotransfer of persistent organic pollutants from a large site in China used for the disassembly of electronic and electrical waste

Samples of groundwater, river water, river sediment, paddy soil, rice seeds, hen eggs, fish, umbilical cord blood, and newborn meconium were collected from October 2002 to October 2003 near a large site in China used for the disassembly of obsolete transformers and other electronic or electrical waste. Six indicator PCB congeners, three non-ortho dioxin-like PCB congeners, and six organochlorine pesticides were determined in the samples by GC with electron capture detector. The results demonstrated that the local environment and edible foods had been seriously polluted by toxic PCBs and organochlorine pesticides. The actual daily intakes (ADIs) of these pollutants were estimated for local residents living in the area. The intake data showed that the contents of PCBs in these local residents were substantial, as the ADI estimates greatly exceed the reference doses set by the World Health Organization and the United States Agency for Toxic Substances and Disease Registry. The presence of the indicator PCB congeners in the cord blood and the meconium samples, as well as significant correlations (r(2) > 0.80, p < 0.05) between these levels, suggests a potential biotransfer of these indicators from mothers to their newborns. This preliminary study showed that obsolete transformers and other electronic or electrical waste can be an important source for the emission of persistent organic pollutants into the local environment, such as through leakage, evaporation, runoff, and leaching. Contamination from this source appears to have reached the level considered to be a serious threat to environmental and human health around the disassembly site.

Characterization of acid-sensing ion channels in dorsal horn neurons of rat spinal cord

Acid-sensing ion channels (ASICs) are ligand-gated cation channels activated by extracellular protons. In periphery, they contribute to sensory transmission, including that of nociception and pain. Here we characterized ASIC-like currents in dorsal horn neurons of the rat spinal cord and their functional modulation in pathological conditions. Reverse transcriptase-nested PCR and Western blotting showed that three ASIC isoforms, ASIC1a, ASIC2a, and ASIC2b, are expressed at a high level in dorsal horn neurons. Electrophysiological and pharmacological properties of the proton-gated currents suggest that homomeric ASIC1a and/or heteromeric ASIC1a + 2b channels are responsible for the proton-induced currents in the majority of dorsal horn neurons. Acidification-induced action potentials in these neurons were compatible in a pH-dependent manner with the pH dependence of ASIC-like current. Furthermore, peripheral complete Freund's adjuvant-induced inflammation resulted in increased expression of both ASIC1a and ASIC2a in dorsal horn. These results support the idea that the ASICs of dorsal horn neurons participate in central sensory transmission/modulation under physiological conditions and may play important roles in inflammation-related persistent pain.

Prenatal exposures to persistent organic pollutants as measured in cord blood and meconium from three localities of Zhejiang, China

Prenatal exposures to persistent organic pollutants were assessed using the levels of PCBs and organochlorine pesticides (OCPs) measured in cord blood and meconium samples from Luqiao and two other localities of the Zhejiang province in China. Luqiao is a town with the largest site for disassembly of PCB-containing obsolete transformers and electrical waste in China. The other two localities Pingqiao (100 km NW of Luqiao) and Lin'an (500 km NW of Luqiao) are towns without known electronic or electrical waste sites. A total of 23 PCB congeners (including 12 dioxin-like) and 6 OCPs were measured using the traditional GC-mu ECD technique. Micro-EROD bioassay was additionally used to measure TCDD-based TEQ levels of the 12 dioxin-like PCBs. Significant correlations were found between the TEQs measured by the two methods, supporting the application of micro-EROD as a practical toot for complementing the chemical analysis. The data showed that beta-HCH, p,p'-DDE, and 6 PCB congeners (101, 138 153, 180, 183, and 187) were the predominant pollutants, with PCB 138 being the best indicator (predictor) for total PCB levels. Cord blood and meconium from Luqiao have higher levels of PCBs than those from the other two localities, suggesting that a disassembly site for electronic and electric waste would provide an environment for greater exposure to these chemicals. The cord blood or meconium levels of beta-HCH, though likewise considerably high, were comparable in the three localities. Similar findings were observed for p,p'-DDE. Pollution by these OCPs might have come from past use of agricultural pesticides in the three localities. (c) 2007 Published by Elsevier B.V.

A Proteomic Study on Cell Cycle Progression of Endothelium Exposed to Tumor Conditioned Medium and the Possible Role of Cyclin D-1/E

This study was designed to comprehensively analyze the differential expression of proteins from human umbilical vein endothelial cells (HUVECs) exposed to tumor conditioned medium (TCM) and to identify the key regulator in the cell cycle progression. The HUVECs were exposed to TCM from breast carcinoma cell line MDA-MB-231, then their cell cycle distribution was measured by flow cytometer (FCM). The role of protein in cell cycle progression was detected via two-dimensional polyacrylamide gel electrophoresis (2-DE) and western blotting. Following the stimulation of TCM, HUVECs showed a more cells in the S phase than did the negative control group (ECGF-free medium with 20% FBS), but the HUVECs' level was similar to the positive control group (medium with 25 mug/ml ECGF and 20% FBS). Increased expression of cyclin D-1/E and some changes in other related proteins occurred after incubation with TCM. From our results, we can conclude that breast carcinoma cell line MDA-MB-231 may secrete soluble pro-angiogenic factors that induce the HUVEC angiogenic switch, during which the expression of cell cycle regulator cyclin D-1/E increases and related proteins play an important role in this process.

The Mitogenic and Anti-Apoptotic Activity of Tumor Conditioned Medium on Endothelium

This study was designed to observe the effect of tumor conditioned medium (TCM) on the proliferation and apoptosis of human umbilical vein endothelial cells (HUVECs). HUVECs were exposed to TCM from breast carcinoma cell line MDA-MB-231, then we measured their proliferation, apoptosis and cell cycle distribution by MTT and flow cytometery (FCM). Following the stimulation of TCM, HUVECs showed higher pro-mitogenic and anti-apoptotic ability than did the negative control group (ECGF-free medium with 20% FBS), but a similar ability to the positive control group (medium with ECGF and 20% FBS). From these results, we can conclude that breast carcinoma cell line MDA-MB-231 could secret soluble pro-angiogenic factors that induce HUVEC angiogenic switching, including cell cycle progression, proliferation and growth. The role and character of these factors remain to be further studied.

Differential expression of the Brunol/CELF family genes during Xenopus laevis early development

The BRUNOL/CELF family of RNA-binding proteins plays important roles in post-transcriptional regulation and has been implicated in several developmental processes. In this study, we describe the cloning and expression patterns of five Brunol genes in Xenopus laevis. Among them, only Brunol2 is maternally expressed and the zygotic expression of the other four Brunol genes starts at different developmental stages. During Xenopus development, Brunol1, 4-5 are exclusively expressed in the nervous system including domains in the brain, spinal cord, optic and otic vesicles. Brunol2 and 3 are expressed in both the somatic mesoderm and the nervous system. Brunol2 is also extensively expressed in the lens. In transfected Hela cells, BRUNOL1, 2 and 3 proteins are localized in both the cytoplasm and the nucleus, while BRUNOL4 and 5 are only present in the cytoplasm, indicating their different functions.

Lentivirus介导神经营养因子- 3促进脊髓损伤大鼠功能恢复

　目的　探讨Lentivirus介导分泌神经营养因子- 3 (NT - 3)直接体内转基因治疗大鼠脊髓损伤作用和机制。　方法　将28只Wistar大鼠在T10水平制成半横断损伤模型,随机分为体内转基因治疗组和损伤对照组,每组14只;用携带NT - 3和绿色荧光蛋白(GFP)的Lentivirus对大鼠行直接体内转基因治疗;荧光显微镜观察体内转基因表达,后肢运动功能评分法(BBB评分) 检测大鼠后肢功能恢复情况。　结果　用荧光显微镜检测到损伤脊髓内有较多的持续表达转基因的细胞; BBB评分结果显示,从伤后第4周开始,实验组大鼠后肢功能较对照组明显恢复( P < 0. 01) ,至第10周时,实验组和对照组BBB分差增大,达3. 3分。　结论　Lentivirus是一种有效的转基因载体,由Lentivirus介导分泌NT - 3的直接体内转基因治疗能够明显促进损伤脊髓的功能恢复。

人胚神经干细胞移植治疗大鼠脊髓损伤

　目的　探讨人胚神经干细胞( hNSC) 移植治疗脊髓损伤(SCI) 的可行性。方法　分 离、培养和鉴定hNSC;用5 溴22 脱氧尿苷嘧啶(BrdU) 标记hNSC ,并将其移植到14 只T10 半横断 的Wistar 大鼠损伤脊髓内(另外14 只T10 半横断损伤的大鼠作为对照组,仅损伤脊髓内注射 DMEM/ F12 培养液) ,用BrdU 的FITC 免疫荧光染色检测移植细胞的存活和迁徙,用NF2200 、 GFAP 免疫组织化学鉴定移植细胞的分化,BBB 评分评定大鼠功能恢复情况。结果　(1) 获得了大 量的hNSC; (2) 用免疫组织化学可以检测到移植的hNSC 能在体内长时间存活(达2 个月) 并向远 处迁徙,并分化为神经元和胶质细胞; (3) 检测到实验组大鼠BBB 得分明显高于对照组大鼠( P < 0. 01) ,在SCI 后第10 周时实验组和对照组BBB 得分最大差距达到2. 1分。结论　hNSC 移植能促 进SCI 大鼠后肢功能恢复,它是SCI 移植治疗较有价值的细胞资源。

Mechanisms of H+ modulation of glycinergic response in rat sacral dorsal commissural neurons

Many ionotropic receptors are modulated by extracellular H+. So far, few studies have directly addressed the role of such modulation at synapses. In the present study, we investigated the effects of changes in extracellular pH on glycinergic miniature inhibitory postsynaptic currents (mIPSCs) as well as glycine-evoked currents (I-Gly) in mechanically dissociated spinal neurons with native synaptic boutons preserved. H+ modulated both the mIPSCs and I-Gly, biphasically, although it activated an amiloride-sensitive inward current by itself. Decreasing extracellular pH reversibly inhibited the amplitude of the mIPSCs and I-Gly, while increasing external pH reversibly potentiated these parameters. Blockade of acid-sensing ion channels (ASICs) with amiloride, the selective antagonist of ASICs, or decreasing intracellular pH did not alter the modulatory effect of H+ on either mIPSCs or I-Gly, H+ shifted the EC50 of the glycine concentration-response curve from 49.3 +/- 5.7 muM at external pH 7.4 to 131.5 +/- 8.1 muM at pH 5.5, without altering the Cl- selectivity of the glycine receptor (GlyR), the Hill coefficient and the maximal I-Gly, suggesting a competitive inhibition of I-Gly by H+. Both Zn2+ and H+ inhibited I-Gly. However, H+ induced no further inhibition of I-Gly in the presence of a saturating concentration of Zn2+. In addition, H+ significantly affected the kinetics of glycinergic mIPSCs and I-Gly. It is proposed that H+ and/or Zn2+ compete with glycine binding and inhibit the amplitude of glycinergic mIPSCs and I-Gly. Moreover, binding of H+ induces a global conformational change in GlyR, which closes the GlyR Cl- channel and results in the acceleration of the seeming desensitization of IGly as well as speeding up the decay time constant of glycinergic mIPSCs. However, the deprotonation rate is faster than the unbinding rate of glycine from the GlyR, leading to reactivation of the undesensitized GlyR after washout of agonist and the appearance of a rebound I-Gly. H+ also modulated the glycine cotransmitter, GABA-activated current (I-GABA). Taken together, the results support a 'conformational coupling' model for H+ modulation of the GlyR and suggest that W may act as a novel modulator for inhibitory neurotransmission in the mammalian spinal cord.

Murine MyaK, a member of a family of yeast YAK1-related genes, is highly expressed in hormonally modulated epithelia in the reproductive system and in the embryonic central nervous system

We have cloned a mouse homologue (designated Myak) of the yeast protein kinase YAK1. The 1210 aa open reading frame contains a putative protein kinase domain, nuclear localization sequences and PEST sequences. Myak appears to be a member of a growing family of YAK1-related genes that include Drosophila and human Minibrain as well as a recently identified rat gene ANPK that encode a steroid hormone receptor interacting protein. RNA blot analysis revealed that Myak is expressed at low levels ubiquitously but at high levels in reproductive tissues, including testis, epididymis, ovary, uterus, and mammary gland, as well as in brain and kidney. In situ hybridization analysis on selected tissues revealed that Myak is particularly abundant in the hormonally modulated epithelia of the epididymis, mammary gland, and uterus, in round spermatids in the testis, and in the corpora lutea in the ovary, Myak is also highly expressed in the aqueduct of the adult brain and in the brain and spinal cord of day 12.5 embryos, Mol. Reprod. Dev. 55:372-378, 2000. (C) 2000 Wiley-Liss, Inc.

Developmental expression of CagMdkb during gibel carp embryogenesis

Midkine (Mdk) genes have been revealed to have different expression patterns in vertebrates and therefore, additional studies on Mdk expression patterns are required in more species. In this study, CagMdkb has been cloned and characterized from a SMART cDNA library of 10-somite stage embryos of Carassius auratus gibelio. Its full length cDNA is 1091 bp and encodes a sequence of 147 amino acids, which shows 97.3% identity to zebrafish Mdkb on the amino acid level. RT-PCR analysis reveals that CagMdkb is first transcribed in gastrula embryos and maintains a relatively stable expression level during subsequent embryogenesis. Western blot analysis reveals a 19 kDa maternal CagMdkb protein band and the zygotic CagMdkb protein is expressed from gastrula stage. At around 10 somite stage, the 19 kDa CagMdkb is processed to another protein band of about 17 kDa, which might be the secreted form with the 21-residue signal peptide removed. With immunofluorescence analysis, maternal CagMdkb protein was found to be localized in each blastamere cell of early embryos. The zygotic CagMdkb positive fluorescence signal was detected from a pair of large neurons at 18-somite stage. At the later stages, CagMdkb protein was also extended to numerous small neurons in the forebrain, midbrain and hindbrain, as well as to nerve fibers in the spinal cord. Co-localization with 3A10 antibody revealed CagMdkb immunoreactivity on developing Mauthner neurons, a member of reticulospinal neurons. In addition, ectopic expression of CagMdkb in early embryos of gibel carp and zebrafish suppressed head formation and CagMdkb function was found to depend on secretory activity. All these findings indicate that CagMdkb plays an important role in neural development during gibel carp embryogenesis and there is functional conservation of Mdkb in fish head formation.

Biphasic regulation of H2O2 on angiogenesis implicated NADPH oxidase

ROS (reactive oxygen species) take an important signalling role in angiogenesis. Although there are several ways to produce ROS in cells, multicomponent non-phagocytic NADPH oxidase is an important source of ROS that contribute to angiogenesis. In the present work, we examined the effects of H2O2 on angiogenesis including proliferation and migration in HUVECs (human umbilical vein endothelial cells), new vessel formation in chicken embryo CAM (chorioallantoic membrane) and endothelial cell apoptosis, which is closely related to anti-angiogenesis. Our results showed that H2O2 dose-dependently increased the generation of O-2(-) (superoxide anion) in HUVECs, which was suppressed by DPI (diphenylene iodonium) and APO (apocynin), two inhibitors of NADPH oxidase. H2O2 at low concentrations (10 mu M) stimulated cell proliferation and migration, but at higher concentrations, inhibited both. Similarly, H2O2 at 4 nmol/cm(2) strongly induced new vessel formation in CAM, while it suppressed at high concentrations (higher than 4 nmol/cm(2)). Also, H2O2 (200 similar to 500 mu M) could stimulate apoptosis in HUVECs. All the effects of H2O2 on angiogenesis could be suppressed by NADPH oxidase inhibitors, which suggests that NADPH oxidase acts downstream of H2O2 to produce O-2(-) and then to regulate angiogenesis. In summary, our results suggest that H2O2 as well as O-2(-) mediated by NADPH oxidase have biphasic effects on angiogenesis in vitro and in vivo.

Amphi-Eomes/Tbr1: An amphioxus cognate of vertebrate Eomesodermin and T-Brain1 genes whose expression reveals evolutionarily distinct domain in amphioxus development

A cDNA for a novel T-box containing gene was isolated from the amphioxus Branchiostoma belcheri. A molecular phylogenetic tree constructed from the deduced amino acid sequence of the isolated cDNA indicates that this gene belongs to the T-Brain subfamily. In situ hybridization reveals that the expression is first detected in the invaginating archenteron at the early gastrula stage and this expression is down-regulated at the neurula stage. In early larvae, the expression appears again and transcripts are detected exclusively in the pre-oral pit (wheel organ-Hatschek's pit of the adult). In contrast to the vertebrate counterparts, no transcripts are detected in the brain vesicle or nerve cord throughout the development. These results are interpreted to mean that a role of T-Brain products in vertebrate forebrain development was acquired after the amphioxus was split from the lineage leading to the vertebrates. On the other hand, comparison of the tissue-specific expression domain of T-Brain genes and other genes between amphioxus and vertebrates revealed that the pre-oral pit of amphioxus has several molecular features which are comparable to those of the vertebrate olfactory and hypophyseal placode. (C) 2002 Wiley-Liss, Inc.