Effects of structurally different noncoplanar and coplanar PCBs on HELF cell proliferation,cell cycle,and potential molecular mechanisms

Polychlorinated biphenyls (PCBs) are a group of chemicals that persist in the environment, indoors, and humans. Lung exposure to airborne and food contaminants, such as PCBs, may cause possible lung disorders, such as cancer. In the present study, we investigated the effects of structurally different lower chlorinated (≤4Cl), noncoplanar PCB40, and coplanar PCB77 on human lung fibroblast cell line (HELF) cell proliferation, cell cycle progression, and possible molecular mechanisms. Noncoplanar PCB40 and coplanar PCB77 exhibited concentration‐ and time‐dependent biphasic dose–response effects on HELF cell proliferation. Noncoplanar PCB40 and coplanar PCB77 induced 23 and 45% cytotoxicity at higher concentrations than the control. The flow cytometry analysis showed that exposure to PCB40 caused a significant increase in time spent in the G1 phase but decreased length of the S phase in a concentration‐ and time‐dependent manner, whereas PCB77 exposure decreased time spent in the G1 and S phases but increased time spent in the G2 phase. Western blot analysis indicated that PCB77 increased the expression of cyclin E, CDK2, p21, and caspase‐9, while PCB40 decreased the expression of these proteins (except CDK2 and p21). An increase in CDK expression after exposure to PCB77 suggests that it may cause carcinogenic effects on HELF cells at higher doses. Our results also demonstrate that the different cytotoxic effects induced by coplanar and nonplanar PCBs were correlated with their structural characteristics; the coplanar congener was more cytotoxic than the nonplanar congener. The study elaborates threshold levels for these chemicals and suggests that the cytotoxicity mechanisms by which PCB congeners act on HELF cells depend on their planarity and chemical structures. Furthermore, the study will be important for developing antidotes to the adverse effects and risk assessment practices for PCBs. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1183–1190, 2017.     

Age-related differences in the sensitivity of the fish immune response to a coplanar PCB

Polychlorinated biphenyls (PCBs) are widespread environmental pollutants. Because of their persistence and bioaccumulation in aquatic organisms (among other factors), the biological impact of PCB exposure on resident fish populations is of particular concern. To assess the effect(s) of an environmentally relevant coplanar PCB congener on the fish immune response, juvenile and aged Japanese medaka (Oryzias latipes) were injected i.p. with either vehicle or PCB 126 (at 0.01 or 1.0 µg/g BW) and examined after 3 and 14 days. CYP1A protein levels, examined as an indicator of PCB exposure, were significantly increased (compared to controls) in all fish treated with the highest PCB dose. Kidney phagocyte superoxide (O₂ ^·–) production was examined to indicate effects upon innate immune function. After 14 days, unstimulated O₂ ^·– production by kidney phagocytes from juvenile and aged medaka treated with the highest PCB dose was significantly increased compared to controls. Stimulated O₂ ^·– production by aged PCB-treated fish was unaffected (compared to controls) at both post-exposure timepoints. However, phagocytes from PCB-treated juvenile medaka demonstrated reduced O₂ ^·– production at 3 days post-exposure and increased levels after 14 days (compared to controls). These results demonstrate the sensitivity of medaka phagocyte function for examining PCB-induced immunotoxicity.     

SYBR-Green实时定量PCR用于Vero宿主细胞DNA残留量的检测

目的:建立基于SYBR-Green荧光染料实时定量PCR检测Vero宿主细胞DNA残留量的方法。方法:提取Vero细胞基因组DNA,设计细胞基因组高度重复顺序AGMr(HindIII)-1基因片段的特异性引物,通过PCR扩增AGMr(HindIII)-1序列中一段特异性cDNA片段,克隆至pGEM-T Vector,重组质粒经酶切及测序鉴定合格后命名为pGEM-T/AGMr(HindIII)-1-S。结果:使用重组质粒和细胞基因组DNA分别作为检测标准品,均取得了良好的结果,其检测灵敏度分别达到了0.03 fg.μL-1和0.03 pg.μL-1。结论:SYBR-Green实时定量PCR可用于Vero宿主细胞DNA残留量的准确定量。     

检测白喉毒素特异性细胞毒性的Vero细胞/MTT法的建立

目的 建立检测白喉毒素（diphtheria toxin,DT）特异性细胞毒性的Vero细胞/MTT法.方法 用MEM培养液对DT进行不同倍数的预稀释,用目测法确定DT的最适预稀释倍数.用建立的方法检测以最适预稀释倍数稀释的DT,以确定该法的灵敏度和细胞病变半数抑制浓度（IC50）,同时绘制剂量-反应曲线以验证该法的重复性.用建立的方法于不同pH、盐浓度或蔗糖浓度条件下检测DT,计算DT回收率以验证该法的耐用性.结果 目测法确定的DT最适预稀释倍数为106倍.建立的方法的平均检测灵敏度为（6.01±1.44）×10^-5 lf/ml DT,细胞病变半数抑制率对数值（log IC50）范围为5.02 ～ 5.82,变异系数为5.82％,该法具有较好的重复性.用建立的方法检测不同条件下的DT显示,DT的平均回收率为93.7％ ～ 110.4％,该法具有较好的耐用性.结论 Vero细胞/MTr法可用于检测DT特异性细胞毒性.     

In vivo and in vitro effects of PCB126 and PCB153 on rat testicular androgenesis

In this study we compared the effects of PCB126 and PCB153 on adult rat testicular androgenesis and the status of antioxidant enzymes in the interstitial cell compartment 96h after local intratesticular application. Obtained results indicated PCB126-induced inhibition of conversion of progesterone (P) and Δ(4)-androstenedione (A(4)) to testosterone (T), and stimulation of conversion of P to T induced by PCB153, while combined application had no effect. Activities of antioxidant enzymes were unchanged, except of decreased activity of SOD in PCB126-treated group. In parallel experiments, adult purified Leydig cells challenged with PCB congeners were incubated for 2h in the presence of corresponding steroid substrates. Results demonstrated that in the presence of subsaturating substrate concentrations PCB126 induced inhibition of conversion of P and A(4) to T at nM to μM doses, while PCB153 caused stimulation at nM concentrations. Further studies should indicate possible mechanism(s) of modulation of androgenesis by tested PCB congeners.     

Perinatal exposure to low doses of PCB 153 and PCB 126 affects maternal and neonatal immunity in goat kids

Pregnant does (10 goats/group) were dosed orally either with polychlorinated biphenyl (PCB) 153 (98 microg/kg body weight/d) or PCB 126 (ng/kg body weight/d) dissolved in corn oil or with corn oil only (control group) from gestation day (GD) 60 until delivery. An additional group (n = 5) of pregnant does received the synthetic estrogen diethylstilbestrol (DES; 0.4 microg/kg body weight/d) by intramuscular injection using the same treatment schedule as for the PCB groups. Blood samples for immune analysis were collected at wk 0, 1, 2, 4, 6, and 8 of age. The effects of perinatal PCB exposure on postnatal humoral immune responses were examined by assessing the levels of total immunoglobulin G (IgG) and immunoglobulins to specific microbes at wk 0, 1, 2, 4, 6, and 8 of age, and immune responses following immunization of kids at 2 wk of age. PCB 153 exposure suppressed maternal and neonatal immunity, as demonstrated by reduced transfer of maternal IgG and specific antibodies to the environmental microbes Arcanobacterium pyogenes, Mannheimia haemolytica, and reovirus (REO-1). Furthermore, PCB 153 reduced the level of maternal antibodies to Mycobacterium avium paratuberculosis and equine influenza virus (EIV-1) in the newborn kids. The antibody response against EIV-1 was significantly higher in PCB 153-exposed kids 2 wk following immunization. PCB 126 exposure reduced the levels of maternal antibodies to REO-1. In contrast, gestational exposure to PCB 126 increased the concentrations of maternal antibodies to tetanus toxoid. No differences from controls in plasma total IgG levels at birth or colostrum IgG concentrations were observed in the PCB 126-treated does. However, a significant reduction in IgG levels from GD 60 until delivery was found in this group. Gestational exposure to DES reduced the concentrations of maternal antibodies against A. pyogenes, M. haemolytica, M. avium Paratuberculosis, and REO-1. These results suggest that perinatal exposure to low doses of PCB 126 and PCB 153 affects the maternal immunity in kids. The difference in responses between PCB 126 and PCB 153 treatment groups may strengthen the hypothesis that PCBs mediate immunotoxic effects through both AhR-dependent and -independent mechanisms. The observation that the effects produced by PCB 153 resembled those produced by DES raises the question of whether this congener may modulate immunity by estrogenic mechanisms.     

Auditory deficits in rats exposed to an environmental PCB mixture during development.

Previous studies have indicated that developmental exposure to polychlorinated biphenyls (PCBs) may result in hearing impairment in rats. The cochlea is the suggested site of action, based upon one study demonstrating a loss of outer hair cells on the basilar membrane, and another demonstrating deficits in distortion product otoacoustic emissions (DPOAEs). The current study was conducted to assess the possible ototoxic effects of a unique PCB mixture formulated to model the congener profile of PCBs found in fish consumed by a human population in northeastern Wisconsin. Female Long-Evans rats were dosed orally with the PCB mixture beginning 28 days prior to breeding and continuing until the pups were weaned. Dams were fed one-half of a cookie onto which was pipetted 0, 1, 3, or 6 mg/kg of the PCB mixture dissolved in a corn oil vehicle. On postnatal day (PND) 21, pups were weaned, and one male and one female from each litter were randomly selected for auditory assessment. DPOAEs were measured to assess cochlear function, and auditory brainstem responses (ABRs) were measured to determine effects on central nervous system auditory pathways. DPOAE amplitudes were decreased, and DPOAE and ABR thresholds were elevated across a range of frequencies in PCB-exposed rats. These results support and extend previous reports of auditory impairment in PCB-exposed rats. Developmental exposure to PCBs may also result in subtle auditory impairments in humans, and if so, this may contribute to some of the cognitive deficits that have been observed in epidemiological studies.     

Effects of perinatal exposure to low doses of PCB 153 and PCB 126 on lymphocyte proliferation and hematology in goat kids

Pregnant does (10 goats/group) were dosed orally with either PCB 153 or PCB 126 dissolved in corn oil or only corn oil (control group) from day 60 of gestation until delivery. Effects on in vitro mitogen-induced lymphocyte proliferation and blood cell counts in their goat kids exposed to low levels of PCB 153 and PCB 126 during gestation and lactation were assessed. The concentrations of PCB 153 and PCB 126 in adipose tissue in the goat kids 9 mo postpartum were 5800 ng/g (fat weight) and 0.49 ng/g (fat weight), respectively. Kids exposed to PCB 153 had a significantly higher number of white blood cells, neutrophils, and lymphocytes at 2 wk of age compared to controls. In the kids exposed to PCB 126 there was a significantly lower concentration of monocytes at 2, 4, and 8 wk of age. The mean lymphocyte response to phytohemagglutinin (PHA) and to concanavalin A (Con A) was significant lower in the PCB 153 compared to the control group at wk 2, 4, and 8 postnatally. The results of the present study support previous reports on immunotoxic effects of PCB exposure in animals. However, this is the first report to demonstrate immunotoxicity in animals by using low doses of PCB 153. The difference in results between PCB 126 and PCB 153 treatment groups may strengthen the hypothesis that PCBs mediate immunotoxic effects through both AhR-dependent and -independent mechanisms.     

Perinatal exposure to PCB 153, but not PCB 126, alters bone tissue composition in female goat offspring

The aim of this study was to investigate if environmentally relevant doses of the putative estrogenic non dioxin-like PCB 153 and the dioxin-like PCB 126 caused changes in bone tissue in female goat offspring following perinatal exposure. Goat dams were orally dosed with PCB 153 in corn oil (98 microg/kg body wt/day) or PCB 126 (49 ng/kg body wt/day) from day 60 of gestation until delivery. The offspring were exposed to PCB in utero and through mother's milk. The suckling period lasted for 6 weeks. Offspring metacarpal bones were analysed using peripheral quantitative computed tomography (pQCT) after euthanisation at 9 months of age. The diaphyseal bone was analysed at a distance of 18% and 50% of the total bone length, and the metaphyseal bone at a distance of 9%. Also, biomechanical three-point bending of the bones was conducted, with the load being applied to the mid-diaphyseal pQCT measure point (50%). PCB 153 exposure significantly decreased the total cross-sectional area (125 mm(2)+/-4) versus non-exposed (142 mm(2)+/-5), decreased the marrow cavity (38 mm(2)+/-4) versus non-exposed (50 mm(2)+/-3) and decreased the moment of resistance (318 mm(3)+/-10) versus non-exposed (371 mm(3)+/-20) at the diaphyseal 18% measure point. At the metaphyseal measure point, the trabecular bone mineral density (121 mg/cm(3)+/-5) was increased versus non-exposed (111 mg/cm(3)+/-3). PCB 126 exposure did not produce any observable changes in bone tissue. The biomechanical testing of the bones did not show any significant changes in bone strength after PCB 153 or PCB 126 exposure. In conclusion, perinatal exposure to PCB 153, but not PCB 126, resulted in altered bone composition in female goat offspring.     

Perinatal co-exposure to methylmercury and PCB153 or PCB126 in rats alters the cerebral cholinergic muscarinic receptors at weaning and puberty

In the last few decades, combined exposure to methylmercury (MeHg) and polychlorinated biphenyls (PCBs) from fish and seafood, and their potentially interactive effects on neurodevelopment, have been giving increasing cause for concern. We examined the combined effects of MeHg and either a non-dioxin PCB (PCB153) or a dioxin-like PCB (PCB126) congener on the developing brain cholinergic muscarinic receptors (MRs). These receptors are known to play a major role in many central functions including higher cognitive processes and the modulation of extrapyramidal motor activity. MRs in pup rat brains diminished following prenatal and lactational exposure, from gestational day [GD]7 to postnatal day [PND]21, to MeHg (0.5mg/kgbodyweight[bw]/day), PCB153 (5mg/kgbw/day), and PCB126 (100ng/kg/day), alone or in combination. Total MR density, as well as M1, M2, and M3 receptor subtypes of the weanling and pubertal rats, were affected in a brain-area-, gender-, time- and compound-dependent fashion. MeHg decreased (by 15-20%) the total MR density in a delayed (PND36) manner in the cerebral cortex of both genders, and early (at weaning) in the cerebellum of both genders, with the effect lasting until puberty (in males only). MeHg decreased the ACh M1- and M3-immunopositive neurons in the cerebral cortex and also increased the M2-immunopositive Bergmann glia in the cerebellum. PCB153 also induced a delayed (PND36) decrease (of 20%) in total MR number in the cerebellum of the male offspring and in the cerebral cortex of both genders. The latter effect was coupled with a decrease in ACh M1- and ACh M3-immunopositive neuron populations. PCB126 decreased (by 30-40%) total MR density in a gender-dependent manner, males being more sensitive than females. The effect was evident early (at PND21) and lasted until puberty in the cerebellum, while it was observed later (at PND36) in the cerebral cortex. The M1 and M3 receptors were similarly affected by PCB126. Co-exposure to MeHg and either PCB153 or PCB126 had the same effect on the cerebral MRs as exposure to each compound alone. The results rule out additive or synergistic interactions between MeHg and PCB153 or PCB126 on MRs in the brain areas examined. Some early-onset changes persisted until puberty, while other modifications became manifest only at the advanced time point (PND36), when the brain levels of total Hg, PCB153, and PCB126 had declined. These data support the ability of MeHg and PCBs to induce delayed neurotoxicity after developmental exposure.     

A physiologically based pharmacokinetic model for lactational transfer of PCB 153 with or without PCB 126 in mice

Chemical exposure via breast milk is one of the great concerns in public health. Previously, we demonstrated that most body burden of PCB 153 can be transferred from the mother to the pups in mice during lactational period. Here we present a physiologically based pharmacokinetic (PBPK) model to describe the lactational transfer of PCB 153 with or without PCB 126 in mice. The model incorporated physiological changes on the volume and the blood flow into mammary tissues, and considered mechanistic information on the movement of PCB 153 from adipose tissue to the mammary gland during lactational period. The mechanistic consideration includes fat volume changes, binding of PCB 153 to very low density lipoprotein (VLDL) and increased uptake of VLDL in mammary tissues. Model parameters depicting physiological changes were obtained from research articles dealing with chemical transfer during lactational period in rodents. Chemical-specific parameters were derived from previous PBPK models focusing on the PCB disposition in rodents. The developed model adequately described the lactational transfer of PCB 153 with or without PCB 126 in mice. Our model will provide a useful mechanistic tool to estimate the disposition of PCBs in diverse experimental designs regarding PCB effects during developmental period and to improve quantitative risk assessment of PCBs in the developing organisms.     

Vero细胞HCP试剂盒在冻干乙型脑炎灭活疫苗生产过程中的应用

目的 通过检测冻干乙型脑炎灭活疫苗（Vero细胞）生产过程各道工序中的细胞残余蛋白,达到控制疫苗中Vero细胞残余蛋白的目的.方法 采用Vero细胞宿主细胞蛋白（host cell protein,HCP）试剂盒,对2009-2012年共65批冻干乙型脑炎灭活疫苗（Vero细胞）在病毒液收获、浓缩、硫酸鱼精蛋白处理、纯化、脱糖和半成品配制阶段中的HCP含量进行检测.结果 2009-2012年,病毒液收获阶段Vero细胞HCP含量无明显差异.2010年工艺优化后,2010-2012年的HCP平均值与2009年相比,在浓缩、硫酸鱼精蛋白处理、纯化、脱糖、半成品配制阶段分别降低了78.83％、83.42％、78.62％、86.88％、86.40％.结论 通过Vero细胞HCP试剂盒的动态监测,可以对生产过程中Vero细胞的残余蛋白含量实施控制.     

Cell death mechanisms in GT1-7 GnRH cells exposed to polychlorinated biphenyls PCB74, PCB118, and PCB153

Exposure to endocrine disrupting chemicals (EDCs) such as polychlorinated biphenyls (PCBs) causes functional deficits in neuroendocrine systems. We used an immortalized hypothalamic GT1-7 cell line, which synthesizes the neuroendocrine peptide gonadotropin-releasing hormone (GnRH), to examine the neurotoxic and endocrine disrupting effects of PCBs and their mechanisms of action. Cells were treated for 1, 4, 8, or 24 h with a range of doses of a representative PCB from each of three classes: coplanar (2,4,4′,5-tetrachlorobiphenyl: PCB74), dioxin-like coplanar (2′,3,4,4′,5′ pentachlorobiphenyl: PCB118), non-coplanar (2,2′,4,4′,5,5′-hexachlorobiphenyl: PCB153), or their combination. GnRH peptide concentrations, cell viability, apoptotic and necrotic cell death, and caspase activation were quantified. In general, GnRH peptide levels were suppressed by high doses and longer durations of PCBs, and elevated at low doses and shorter timepoints. The suppression of GnRH peptide levels was partially reversed in cultures co-treated with the estrogen receptor antagonist ICI 182,780. All PCBs reduced viability and increased both apoptotic and necrotic cell death. Although the effects for the three classes of PCBs were often similar, subtle differences in responses, together with evidence that the combination of PCBs acted slightly different from individual PCBs, suggest that the three tested PCB compounds may act via slightly different or more than one mechanism. These results provide evidence that PCB congeners have endocrine disrupting and/or neurotoxic effects on the hypothalamic GnRH cell line, a finding that has implications for environmental endocrine disruption in animals.     

国产与进口牛血清促进Vero细胞生长的比较

 目的  通过对国产与进口牛血清促进Vero细胞生长的比较,筛选可替代进口血清用于轮状病毒疫苗生产中Vero细胞培养的国产牛血清。方法  以国产的3批胎牛血清和1批新生牛血清为待评血清,以进口胎牛血清为对照血清,制备细胞培养液。在T175细胞培养瓶（T瓶）和2层细胞工厂中连续传代培养Vero细胞各3代,观察每一代次的培养上清液、细胞形态和细胞汇合度,计算细胞收获量和与对照血清相比较的相对增长率。采用单样本t检验对细胞收获量与生产要求的细胞产量（T瓶：>1.50×10⁷ 个/ml;细胞工厂：>3.00×10⁸ 个/ml）进行比较。根据细胞相对增长率判断国产血清与进口对照血清促细胞生长活性的相近程度。结果  国产血清培养的Vero细胞生长状态均良好。T瓶培养时,国产血清组的细胞收获量为（1.56～9.30）×10⁷ 个/ml,与生产要求细胞产量的差异有统计学意义（t=2.44～3.76,P<0.05）,且t值均>0,说明符合生产要求。细胞相对增长率接近或超过100%。细胞工厂培养时,国产血清组的细胞收获量为（1.80～4.92）×10⁸ 个/ml,与生产要求产量的差异无统计学意义（t=－0.23～1.16,P>0.05）,但是只有1批胎牛血清和新生牛血清的细胞收获量均值>3.00×10⁸ 个/ml,且细胞相对增长率>90%。 结论  经与进口牛血清比较,国产的1批胎牛血清和1批新生牛血清可替代进口血清,用于轮状病毒疫苗生产中的Vero细胞培养。     

Hormetic effects of noncoplanar PCB exposed to human lung fibroblast cells (HELF) and possible role of oxidative stress

Hormesis, a biphasic dose–response phenomenon, which is characterized by stimulation of an end point at a low‐dose and inhibition at a high‐dose. In the present study we used human lungs fibroblast (HELF) cells as a test model to evaluate the role of oxidative stress (OS) in hormetic effects of non coplanar PCB 101. Results from 3‐(4,5‐dime‐thylthiazol‐2‐yl)‐2,5‐diphenyltetrazo‐lium bromide (MTT) assay indicated that PCB101 at lower concentrations (10^?5 to 10^?1 μg mL^?1) stimulated HELF cell proliferation and inhibited at high concentrations (1, 5, 10, and 20 μg mL^?1) in a dose‐ and time‐dependent manner. Reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD) (except 48 h) showed a significant increase at higher concentrations of PCB 101 than those at the lower concentrations with the passage of time. Antioxidant enzymes such as glutathione peroxidase (GSH‐Px) exhibited decreasing trends in dose and time dependent manner. Lipid peroxidation assay resulted in a significant increase (P < 0.05) of MDA level in PCB 101‐treated HELF cells compared with controls, suggesting that OS plays a key role in PCB 101‐induced toxicity. Comet assay indicated a significant increase in genotoxicity at higher concentrations of PCB 101 exposure compared to lower concentrations. Overall, we found that HELF cell proliferation was higher at low ROS level and vice versa, which revealed activation of cell signaling‐mediated hormetic mechanisms. The results suggested that PCB 101 has hormetic effects to HELF cells and these were associated with oxidative stress. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1385–1392, 2015.     

Neurobehavioral assessment of rats exposed to low doses of PCB126 and methyl mercury during development

Epidemiological and laboratory studies have suggested that polychlorinated biphenyls (PCBs) and methyl mercury (MeHg) may have additive or synergistic effects on CNS function. Aim of this study was to characterize the effects of exposure to low levels of MeHg (0.5mg/kgday in drinking water) and PCB126 (100ng/kgday in food), alone and in combination, on neurobehavioral development in Wistar rats. Dams were treated from gestational day 7 to post-natal day (PND) 21. Animals were tested for developmental landmarks and reflexes (PND1-21), attention deficits (PND40), locomotor activity (PND30, 110), spatial learning (PND75), coordination and balance (PND90), object discrimination (PND80), anxiety (PND100), and conditioned learning (PND110). Parameters related to pregnancy, sex ratio at birth, and physical development (at weaning) did not differ among groups, though PCB126 decreased number of pups at birth. A slight delay in negative geotaxis was found in female rats in all treatment groups. No significant effects were seen in attention, coordination and balance, object discrimination, and spatial and conditioned learning. Increased motor activity was present in PCB126-treated male and in MeHg+PCB-treated female rats in the elevated plus maze test, and in PCB126-treated male rats in the open field test (PND110). The results do not support the hypothesis that co-exposure to MeHg and PCB126 results in additive or synergistic effects. This finding is in agreement with more recent in vitro and in vivo studies.     

Exposure to mixtures of endosulfan and zineb induces apoptotic and necrotic cell death in SH-SY5Y neuroblastoma cells, in vitro

A number of epidemiological studies have demonstrated a strong association between the incidence of Parkinson's disease and pesticide exposure. Earlier it was demonstrated that exposure to the pesticides endosulfan and zineb, alone and in combination, caused neurodegeneration in vivo. It was hypothesized that these pesticides cause neurotoxicity, in part, by enhancing apoptotic cell death. SH-SY5Y human neuroblastoma cells, which retain a catecholaminergic phenotype, were exposed to endosulfan, zineb or a combination of these chemicals, in vitro. For mixture studies, concentrations of pesticides (100 microM each) were chosen based on LC(25) (lethal concentration) that would result in minimum cell death. Exposure to a mixture of pesticides exhibited significantly (P < or = 0.05) higher toxicity than each one alone. Both pesticides were found to cause apoptotic cell death that was concentration (50-400 microM) dependent. A flow cytometric (7-aminoactinomycin D) assay was used to distinguish live, early apoptotic and late apoptotic/necrotic populations. Exposure to mixtures of the pesticides enhanced both early apoptosis and late apoptosis/necrosis compared with either chemical alone. Visual evaluation using a DNA ladder assay and a fluorescence Annexin V/PI assay confirmed the contribution of both apoptotic and necrotic processes. These findings suggest that the cytotoxicity of endosulfan and zineb, both individually and in mixtures, is associated with the occurrence of early and late apoptotic/necrotic processes in SH-SY5Y human neuroblastoma cells and support the contention that pesticide-induced neuronal cell death leading to neurodegenerative disease may, at least in part, be associated with early and late apoptosis of dopaminergic neurons.     

Effects on bone tissue in ewes (Ovies aries) and their foetuses exposed to PCB 118 and PCB 153

The aim of the present study was to investigate whether low levels of mono-ortho PCB 118 and di-ortho PCB 153, affect bone composition and strength in ewes (Dala breed) and their foetuses following exposure starting at conception and ending a week before expected delivery. In male foetuses, trabecular bone mineral content at the metaphysis was almost 30% lower in the PCB 118 (49 μg/kg body wt/day) group compared to the control group (corn oil) (ANCOVA, P < 0.05). In female foetuses of the PCB 153 (98 μg/kg body wt/day) group trabecular cross-sectional area at the metaphysis was 19% smaller than in the controls (ANCOVA, P<0.05). At the diaphysis a smaller marrow cavity area (up to 24% reduction) was observed in female and male foetuses exposed to PCB 153 compared with controls (ANCOVA, P < 0.05). There were also significant differences at the mid diaphyseal measure point between the PCB 153 and the control group females (ANCOVA, P < 0.05). Cortical and total bone mineral density, cortical thickness were significantly higher, endosteal circumference shorter and marrow cavity significantly smaller in the PCB 153 group (ANCOVA, P < 0.05).     

冻干Vero细胞狂犬病纯化疫苗在120例门诊病人中的临床效果

目的:观察国产冻干非洲绿猴肾传代细胞(Vero细胞)为基质制备的狂犬病纯化疫苗临床应用的免疫效果和安全性。方法:选择门诊部就诊的犬致伤者240例,分为试验组和对照组。试验组接种冻干Vero细胞狂犬病纯化疫苗,对照组接种地鼠肾狂犬病纯化疫苗。2组人群均按照狂犬病疫苗暴露后常规免疫程序进行接种,于全程接种后15d测定中和抗体,并观察不良反应。结果:试验组抗体阳性率为96.7%,明显高于对照组的90.0%,P<0.05;不良反应发生率为10.8%,明显低于对照组的21.7%,P<0.05。结论:Vero细胞纯化疫苗抗体阳转率高、不良反应发生率低,临床应用优于地鼠肾纯化疫苗,适宜推广使用。