低剂量双酚A及其与苯并芘联合染毒对人乳腺上皮细胞MDM2基因的影响

目的观察BPA与B[a]P联合作用对3种乳腺上皮细胞MDM2及TP53基因表达的影响。方法采用细胞增殖荧光法检测环境相关剂量BPA对3种乳腺上皮细胞S期细胞比例的影响,采用实时荧光定量PCR和蛋白免疫印迹的方法分别检测环境相关剂量水平(10-9、10-7mol/L)BPA及其与10-6mol/L B[a]P联合作用对3种乳腺上皮细胞中MDM2和TP53基因及其编码的蛋白表达水平的影响。结果环境相关剂量的BPA可以引起MCF-7细胞S期细胞比例增高;环境相关剂量的BPA单独作用对3种类型乳腺上皮细胞MDM2和TP53基因表达水平无显著影响;B[a]P单独作用可以引起MCF-10A细胞中MDM2基因表达水平的轻微增加及MCF-7细胞中MDM2基因表达的显著增加;在MCF-7细胞中BPA与B[a]P联合作用可明显增加B[a]P所引起的MDM2基因表达上调,而在HMEC和MCF-10A细胞未发现该现象,蛋白水平与mRNA水平的改变基本一致,同时p53/mdm2比值降低。结论环境相关剂量的BPA与B[a]P联合作用可以在雌激素受体表达阳性的MCF-7细胞中引起MDM2基因及其蛋白产物表达水平的显著上调,提示环境暴露剂量的BPA可能通过雌激素受体依赖的作用途径增加化学致癌物致乳腺癌发生风险。     

小白菊内酯抑制胎牛血清诱导的大鼠血管平滑肌细胞增殖及信号转导机理

目的　探讨小白菊内酯的抗动脉粥样硬化机理与IκBα ,环氧合酶 2 (COX 2 ) ,p2 1,p2 7蛋白表达的关系。方法　培养大鼠胸主动脉血管平滑肌细胞(VSMC) ,Western印迹杂交法检测IκBα ,COX 2 ,p2 1,p2 7蛋白表达 ,流式细胞仪检测VSMC周期情况 ,[3H ]TdR参入测定VSMC的DNA合成。结果小白菊内酯 (30 μmol·L- 1)以时间依赖关系上调IκBα ,p2 1,p2 7蛋白表达和以时间依赖关系抑制COX 2蛋白表达 ,10～ 30 μmol·L- 1以剂量依赖关系使VSMC周期中的G0 /G1期细胞比例明显增多 ,S期细胞比例显著减少 ,同时抑制VSMC的 [3H]TdR参入。结论　①小白菊内酯可能通过上调IκBα蛋白表达抑制核因子 κB活性 ,从而抑制COX 2蛋白表达 ,通过抑制COX 2蛋白表达来抑制VSMC增殖 ;②小白菊内酯可能通过上调调控G1 S周期转换的p2 1,p2 7蛋白来抑制VSMC增殖。     

慢性苯并[a]芘暴露对P53表达及大鼠神经细胞凋亡的影响

<正>苯并[a]芘(benzo[a]pyrene,B[a]P)作为一种重要的环境和职业性污染物,主要来源于煤和石油等矿物质燃料的不完全燃烧。B[a]P是由一个苯环和一个芘分子结合而成的多环芳烃类化合物,具有脂溶性,它的化学性质决定了B[a]P及其代谢产物可以通过血脑屏障并对脑组织产生损伤[1]。人群流行病学调查和动物实验均提示B[a]P暴露可以导致以学习记忆损伤为主要表现的神经退行性表现,并伴随有DNA     

牛磺酸对苯并[a]芘短期暴露小鼠学习记忆与焦虑样行为的影响

目的观察牛磺酸对苯并[a]芘(B[a]P)短期暴露致小鼠学习记忆与焦虑样行为的影响,探讨牛磺酸改善B[a]P神经毒性的可行性。方法选取12周龄健康雄性昆明小鼠48只,按体重采用随机数字表法分为对照组(橄榄油)、B[a]P染毒组(5 mg/kg·bw)、B[a]P(5 mg/kg·bw)+牛磺酸(150 mg/kg·bw)组及牛磺酸(150 mg/kg·bw)组,每组12只,橄榄油和B[a]P隔日腹腔注射,牛磺酸通过灌胃给药,1次/d,持续30 d。旷场试验观察焦虑样行为,Morris水迷宫测试小鼠学习记忆功能。结果旷场实验结果显示,与对照组比较,B[a]P组小鼠旷场区探索的总运动距离和周边区运动距离明显增加,中央区进入次数、中央区停留时间和直立次数明显减少,上述指标差异均有统计学意义(P0.05);与B[a]P组比较,B[a]P+牛磺酸组小鼠的总运动距离、周边区运动距离明显减少,中央区进入次数、中央区停留时间明显增加,上述指标差异均有统计学意义(P0.05);与对照组比较,牛磺酸组小鼠上述测试结果未出现明显改变,差异无统计学意义(P0.05)。Morris水迷宫实验结果显示,与对照组比较,B[a]P组小鼠在定位航行测试中的登台潜伏期明显延迟,从第2天开始,差异有统计学意义(P0.05),探索测试中的首次登台时间明显延长、穿越平台次数和平台象限停留时间明显减少,上述指标差异均有统计学意义(P0.05);与B[a]P组比较,B[a]P+牛磺酸组小鼠在定位航行测试中的登台潜伏期明显缩短,在探索测试中首次登台时间明显缩短、穿越平台次数和平台象限停留时间明显增加,上述指标差异均有统计学意义(P0.05);与对照组比较,牛磺酸组小鼠上述测试结果未出现明显改变,差异无统计学意义(P0.05)。结论 B[a]P短期暴露可导致小鼠空间学习记忆能力损伤,引起焦虑样行为的改变。牛磺酸对B[a]P短期暴露诱发的小鼠学习记忆损伤和焦虑样行为有改善作用。     

侧脑室注射苯并[a]芘对大鼠脑组织病理学改变和学习记忆的影响

目的研究侧脑室注射苯并(a)芘(B[a]P)对大鼠学习记忆的影响及脑组织病理学的变化。方法分别以0.9%氯化钠注射液、5.0mmol/L B[a]P、10.0mmol/L B[a]P无菌溶液10μL给大鼠侧脑室注射染毒,于染毒结束8d后用Morris水迷宫、跳台和避暗试验等测定大鼠的学习记忆能力。处死后用苏木精-伊红(HE)染色观察大脑皮质和海马CA1区病理组织学的变化。结果染B[a]P组大鼠跳台、避暗实验潜伏期和空间探索试验中目标象限停滞时间较对照组显著缩短(P<0.05),错误次数显著增多(P<0.05),且有剂量反应关系,表明B[a]P可导致大鼠神经行为发生改变,学习记忆障碍。随着染B[a]P剂量增加,大鼠皮质和海马CA1区细胞连接松解,排列逐渐零乱,有环状带出现,细胞数目减少,细胞核、胞体变小。表明随着染B[a]P剂量的增加,大鼠皮质和海马CA1区神经细胞形态结构改变越明显。结论 B[a]P可致大鼠学习记忆发生障碍,且随染B[a]P剂量增加对大鼠造成的损伤越大,可为B[a]P神经毒性的研究提供良好的实验基础。     

反式二氢二醇环氧苯并芘诱发细胞P53基因的变化

目的　观察苯并(a)芘[B(a)P]代谢产物反式二氢二醇环氧苯并芘[anti 7,8, dihydrodiol 9,10 epoxidebenzo(a)pyrene ,BPDE]诱发的恶性转化的人支气管上皮细胞(humanbronchialepithelialcells ,HBE)及其裸鼠成瘤细胞中的p5 3基因突变情况,探讨BPDE诱导细胞癌变的机制。方法　多聚酶链聚合反应 单链构象多态性分析(PCR SSCP)、基因测序。结果　PCR SSCP分析结果提示,反式BPDE诱发的恶性转化细胞及其裸鼠成瘤细胞p5 3基因的Exon 7和Exon 8有突变。基因测序发现裸鼠成瘤细胞(B3 )的p5 3基因Exon 8的第2 82位密码子位置出现了一个G→T点突变,其编码的氨基酸由精氨酸(CGG)→亮氨酸(CTG)。结论　反式BPDE可诱导p5 3基因发生突变,提示p5 3基因突变可能是BPDE诱导细胞癌变的重要机制之一。     

苯并[a]芘通过CXCL12/CXCR4轴影响早孕小鼠子宫内膜炎症反应CSCD

目的探讨CXCL12/CXCR4轴在苯并[a]芘(Benzo[a]pyrene,B[a]P)影响早孕小鼠胚胎着床过程中的作用及其机制。方法将8周龄昆明小鼠每晚按雌雄2∶1比例合笼,次晨将查得阴栓者记为孕第1天(D1),并随机分为对照组和B[a]P组。B[a]P组孕鼠每日晨称重后以0.1 ml/10 g动物体重灌胃给予0.2 mg/(kg·d)B[a]P,对照组则灌胃等体积玉米油。体外分离小鼠原代子宫内膜基质细胞,将其分为对照组、B[a]P组和rhCXCL12+BaP联合处理组。ELISA法检测小鼠血清CXCL12水平;qRT-PCR、Western blot和免疫组化法检测CXCL12、CXCR4的表达;qRT-PCR和Western blot检测炎症因子IL-1β、IL-10、NLRP3和TNF-α的表达;Western blot检测着床相关因子MUC1、MMP9和HOXa10的表达情况。结果与对照组相比,B[a]P暴露明显降低孕早期小鼠血清中CXCL12含量,同时下调小鼠子宫组织及基质细胞内CXCL12和CXCR4的表达,抑制炎症反应的发生,影响着床相关因子表达。上调小鼠原代子宫内膜基质细胞内CXCL12表达,可缓解B[a]P所导致的炎症抑制和着床相关因子表达异常。结论B[a]P可能通过下调CXCL12/CXCR4表达,抑制炎症反应,影响孕早期小鼠胚胎植入过程。     

古交区土法炼焦与肺癌危险的流行病学调查

<正> 土法炼焦操作原始,生产过程中可释放大量有害物质,其中危害最大的是以苯并[a]芘(B[a]P)为代表的致癌性多环芳烃。本次除对受土焦污染程度不同的乡镇分别进行了肺癌危险的流行病学调查外,并对土法炼焦作业现场进行了B[a]P的测定。     

住院精神病患者猝死与抗精神病药物的关系

猝死是指直至死前 2 4小时仍无死亡迹象的非预期突然死亡[1] 。据国内外有关报道 ,精神科住院患者的猝死率明显高于综合医院住院病人的猝死率[2 ] ,住院精神患者猝死发生率约为 7‰[3] 。精神科住院患者猝死情况比较复杂 ,猝死的原因与抗精神病药物及躯体因素等有关[4 ] 。本文仅就住院精神病患者猝死与抗精神病药物的关系作一阐述。1　猝死与抗精神病药物的关系目前猝死与抗精神病药物的关系尚无定论 ,与之有关的猝死发生率亦无报道。有报道表明药源性猝死者占精神科猝死者的 77 96 % [5] 。各类抗精神病药治疗特点不同 ,其不良反应也比较…     

MgCl2和Gpp（NH）p对腺苷A1受体激动剂和拮抗剂结合的作用比较

AIM: To investigate modulation of antagonist and agonist binding to adenosine A1 receptors by MgCI2 and 5'-guanylimidodiphosphate (Gpp(NH)p) using rat brain membranes and the A1 antagonist [^3H]-8-cyclopentyl-1,3-dipropylxanthine ([^3H]DPCPX) and the A1 agonist [^3H]-2-chloro-N^6-cyclopentyladenosine ([^3H]CCPA). METHODS:Parallel saturation and inhibition studies were performed using well-characterised radioligand binding assays and aBrandel Cell Harvester. RESULTS: MgCI2 produced a concentration-dependent decrease (44%), whereasGpp(NH)p increased [^3H]DPCPX binding (19%). In [^3H]DPCPX competition studies, agonist affinity was 1.5-14.6-fold higher and 4.6-10-fold lower in the presence of l0 mmol/L MgCl2 and l0μmol/L Gpp(NH)p respectively;antagonist affinity was unaffected. The decrease in agonist affinity with increasing Gpp(NH)p concentrations was due to a reduction in the proportion of binding to the high affinity receptor state. In contrast to [^3H]DPCPX, MgCl2produced a concentration-dependent increase (72%) and Gpp(NH)p a decrease (85%) in [^3H]CCPA binding.Using [^3H]CCPA, agonist affinities were 5-17-fold higher than those for [^3H]DPCPX, consistent with binding onlyto the high affinity receptor state. Agonist affinity was 1.3-10.5-fold higher and 2.4-4.7-fold lower on addingMgCl2 or Gpp(NH)p respectively; antagonist affinities were as for [^3H]DPCPX. CONCLUSION: The inconsistencies surrounding the effects of MgCl2 and guanine nucleotides on radioligand binding to adenosine A1 receptorswere systematically examined. The effects of MgCl2 and Gpp(NH)p on agonist binding to A1 receptors are consistent with their roles in stimulating GTP-hydrolysis at the G-protein α-subunit and in blocking formation of the highaffinity agonist-receptor-G protein complex.     

Effect of in vitro exposure to benzo[a]pyrene, a component of cigarette smoke, on folliculogenesis, steroidogenesis and oocyte nuclear maturation

We previoulsy quantified the concentration of benzo[a]pyrene (B[a]P) in the follicular fluid of women exposed to mainstream and/or sidestream cigarette smoke. The objective of this study was to quantify the effects of B[a]P-exposure, at concentrations representative of follicluar fluid concentrations, on folliculogenesis, on gonadal steroid and anti-müllerian hormone (AMH) output, oocyte growth, and nuclear maturation. Follicles (100-130 μm) isolated from ovaries of F1 hybrid (C57BL/6j×CBA/Ca) mice were cultured for 13 days in increasing concentrations of B[a]P (0 ng/ml (control) to 45 ng/ml). B[a]P treatment inhibited (p < 0 .05) antral follicle development, decreased estradiol output and follicle survival at the 45.0 ng/ml dose. B[a]P exposure decreased AMH output overall during preantral (p = 0.014) and antral (p = 0.026) follicle development but had no effect on progesterone output or oocyte growth and nuclear maturation in surviving follicles. These data suggest that B[a]P is an important toxic component of cigarette smoke that adversely affects follicular development and survival.     

Quantification of benzo[a]pyrene and other PAHs in the serum and follicular fluid of smokers versus non-smokers

Cigarette smoking is a well-established reproductive hazard that has been linked with decreased fertility in both smokers and those exposed to second hand smoke. The chemical components responsible for the reproductive toxic effects of cigarette smoke are unknown. Moreover, exposure of reproductive tissues to the chemical constituents of cigarette smoke is largely unknown. Therefore, we measured the levels of benzo[a]pyrene (B[a]P), and other polycyclic aromatic hydrocarbons (PAH) present in cigarette smoke, in the serum and follicular fluid of women exposed to mainstream (n=19) and side stream smoke (n=7) compared to non-smokers (n=10). Women exposed to mainstream smoke had significantly higher levels of B[a]P (1.32+/-0.68ng/ml) in their follicular fluid compared to side stream exposed (0.05+/-0.01ng/ml) or their non-smoking (0.03+/-0.01ng/ml) counterparts. More importantly we found significantly higher (p<0.001) levels of B[a]P in the follicular fluid of women who did not conceive (1.79+/-0.03ng/ml) compared to those that achieved a pregnancy (0.08+/-0.03ng/ml). Other PAHs known to be present in cigarette smoke were also detectable in both serum and follicular fluid of study subjects studied but with lower frequency compared to B[a]P and no differences in serum or follicular fluid levels between the groups could be demonstrated. The important finding that B[a]P reaches the follicular fluid and the fact that it is found at much higher levels in women who smoke provides further evidence that of the many toxicants present in cigarette smoke, B[a]P may be a key compound that is central to the documented adverse effects of cigarette smoke on follicular development and subsequent fertility.     

Aldo-keto reductases protect lung adenocarcinoma cells from the acute toxicity of B[a]P-7,8-trans-dihydrodiol

Tobacco smoke exposure stimulates the expression of genes that are likely to be involved in the metabolism of its combustion products such as polycyclic aromatic hydrocarbons (PAH). Four of the smoke induced genes are aldo-keto reductases (AKR), enzymes that metabolically activate PAH to PAH o-quinones. Alternatively, PAHs are metabolized to (±)-anti-diol epoxides, such as (±)-anti-benzo[a]pyrene diol epoxide ((±)-anti-BPDE)), by the combined action of P4501A1/1B1 and epoxide hydrolase. (±)-anti-BPDE forms DNA adducts directly, while PAH o-quinones cause DNA damage by oxidative stress through a futile redox cycle. To address the role of AKRs in PAH cytotoxicity, we compared the cytotoxicity of PAH metabolites and the effects of overexpressing AKR1A1 in lung cells. (±)-anti-BPDE and B[a]P-7,8-trans-dihydrodiol, an intermediate in (±)-anti-BPDE metabolism, are toxic to A549 cells at concentrations with an IC(50) of ～2 μM. In contrast, the PAH o-quinone B[a]P-7,8-dione was about 10-fold less toxic to A549 cells with an IC(50) > 20 μM. Similar differences in cytoxicity were observed with two other PAH o-quinones (benz[a]anthracene-3,4-dione and 7,12-dimethylbenz[a]anthracene-3,4-dione) compared with their respective diol-epoxide counterparts (BA-3,4-diol-1,2-epoxide and DMBA-3,4-diol-1,2-epoxide). In addition, both anti-BPDE and B[a]P-7,8-trans-dihydrodiol induced p53 expression ～6 h post-treatment at concentrations as low as 1 μM consistent with extensive DNA damage. B[a]P-7,8-dione treatment did not induce p53 but generated reactive oxygen species (ROS) in A549 cells and induced the expression of oxidative response genes in H358 cells. We also observed that overexpression of AKR1A1 in H358 cells, which otherwise have low levels of AKR expression, protected cells 2-10-fold from the toxic effects of B[a]P-7,8-trans-dihydrodiol. These data suggest that overexpression of AKRs may protect lung cancer cells from the acute toxic effects of PAH.     

Benzo(a)pyrene induces oxidative stress,pro-inflammatory cytokines,expression of nuclear factor-kappa B and deregulation of wnt/beta-catenin signaling in colons of BALB/c mice

The incidence of colonic toxicity has been epidemiologically linked to the consumption of foods contaminated with benzo(a)pyrene (B[a]P). The present study investigated the effects of B[a]P on biomarkers of oxidative stress, inflammation and wnt-signaling in colon of BALB/c mice following exposure to 62.5, 125 and 250 mg/kg of B[a]P for 7 days by oral gavage. Exposure to B[a]P significantly decreased the colonic antioxidant enzymes activities and glutathione level with concomitant significant increase in myeloperoxidase activity, nitric oxide and lipid peroxidation levels. Colon histopathology results showed treatment-related lesions characterized by atrophy, mucosal ulceration and gland erosion in the B[a]P-treated mice. Immunohistochemistry analysis showed that B[a]P treatment increased the protein expression of nuclear factor kappa B, pro-inflammatory cytokines namely tumor necrosis factor alpha and interleukin-1β, as well as cyclooxygenase-2 and inducible nitric oxide synthase in the mice colon. Altered canonical wnt-signaling was confirmed by strong diaminobenzidine staining for p38 mitogen activated protein kinase, β-catenin expression and absence of adenomatous polyposis coli following B[a]P administration. The present data highlight that exposure to B[a]P induces colon injury via induction of oxidative and nitrosative stress, inflammatory biomarkers and dsyregulation wnt/β-catenin signaling, thus confirming the role of B[a]P in the pathogenesis of colonic toxicity.     

Gaseous nitrogen oxide repressed benzo[a]pyrene-induced human lung fibroblast cell apoptosis via inhibiting JNK1 signals

Benzo[a]pyrene (B[a]P) is present in environmental pollution and cigarette smoke. B[a]P has been shown to induce apoptosis in hepatoma cells, human B cells, human ectocervical cells, macrophages, and rat lungs. Nitrogen oxides (NOx) are the other important indoor and outdoor air pollutants. Many studies have indicated that NO gas causes lung tissue damage both by its oxidative properties and free radicals. In our previous study we demonstrated that NO gas induced proliferation of human lung fibroblast MRC-5 cells. In this study we showed that NO gas inhibits B[a]P-induced MRC-5 cells apoptosis by cell cycle analysis. Western blot data revealed that NO gas increased the expressions of anti-apoptosis proteins (Bcl-2 and Mcl-1) and decreased the expression of apoptosis proteins (Bax, t-Bid, cytochrome c, FasL, and caspases) after B[a]P treatment. We further clarified that B[a]P-induced MRC-5 cell apoptosis via JNK1/FasL and JNK1/p53 signals. In conclusion, NO gas inhibited B[a]P-induced MRC-5 cells apoptosis via inhibition of JNK1 apoptosis pathway and induction of Bcl-2 and Mcl-1 anti-apoptosis pathway.     

Differences in gene expression and benzo[a]pyrene-induced DNA adduct formation in the liver of three strains of female mice with identical AhRb2 genotype treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin and/or benzo[a]pyrene

To search for genes whose products modify aryl hydrocarbon receptor (AhR)-dependent toxicity caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), gene expression profiles in the liver were surveyed using microarrays 24 h after the administration of TCDD to three strains of female mice, BALB/cAnN (BALB), C3H/HeN (C3H) and CBA/JN (CBA) all of identical AhR genotype. The BALB/cAnN strain had a more marked induction of a number of glutathione S-transferase (GST) sub-families, particularly the GSTmicro gene family, compared with the other two strains. To assess the effects of GSTs induction to metabolize carcinogens, TCDD (40 microg kg(-1)) was administered to BALB and CBA strains, followed 24 h later by an i.p. injection of low or high dose of benzo[a]pyrene (B[a]P, 50 or 200 mg kg(-1)). The 32P-postlabelling analysis showed that administration of TCDD alone failed to induce DNA adduct formation in both BALB and CBA strain mouse livers. The low dose of B[a]P alone produced DNA adduct in the liver of both strains to a similar extent. Treatment with TCDD 24 h before the low dose of B[a]P suppressed the formation of B[a]P-induced DNA-adduct more markedly in the BALB strain compared with the CBA strain. Taken together, these findings show that TCDD treatment causes strain-specific alterations in gene expression and B[a]P-induced DNA adduct formation in the liver of female mice of the same AhRb2 genotype. Furthermore, it suggests that TCDD-treated female mice of the BALB strain may have genes whose products modify the toxicity of B[a]P as evidenced by TCDD-induced alterations in B[a]P-DNA adduct formation.     

Feasibility of a simple double-layered coculture system incorporating metabolic processes of the intestine and liver tissue: application to the analysis of benzo[a]pyrene toxicity.

A simple double-layered coculture system using Caco-2 cell and Hep G2 cell, which mimic metabolic processes occurring in humans such as absorption through the intestine and cytochrome P450 1A1/2 involving biotransformation in both the intestine and liver cells, was used to investigate the toxicity of model chemical, benzo[a]pyrene (B[a]P). It was found that both Caco-2 and Hep G2 cells can metabolize B[a]P to toxic metabolites including B[a]P-7,8-hydrodiol (7,8-diol), an immediate precursor to the highly-reactive ultimate toxicant of B[a]P, B[a]P-7,8-hydrodiol-9,10-epoxide (BPDE), possibly mediated by cytochrome P450 1A1/2 activity. However, in a double-layered coculture system, no significant reduction of Hep G2 cell viability was found, although an approximately 50% reduction in viability was observed in pure Hep G2 cells. HPLC analysis showed that Caco-2 cells transfer B[a]P and its toxic metabolites back to the apical side, thus decreasing the concentrations of toxic metabolites including B[a]P-7,8-hydrodiol (7,8-diol) in cocultured Hep G2 cells. These results appear to be correlated with in vivo data on the effects of orally administered B[a]P, that is, low (10%) bioavailability in the rats and almost no acute lethal toxicity in rats or mice. As such, the simple double-layered coculture system can provide more accurate information regarding the toxic actions of the hazardous chemicals in humans than a pure culture system, as it also gives the final toxicity as a result of many complicated phenomena such as selective permeation in the intestine and biotransformation in the intestine and liver.     

Detection of immunotoxicity of benzo[a]pyrene in a subacute toxicity study after oral exposure in rats.

In an extended OECD 407 study protocol, including immune parameters, male Riv:Tox Wistar SPF rats were treated for 35 days with benzo[a]pyrene (B[a]p) (3, 10, 30, or 90 mg/kg body weight) by gavage. Oral administration of B[a]p in rats resulted not only in general toxicity, as indicated by the effects on body weight, but also in immunotoxicity, as indicated by the effects on bone marrow, thymus, spleen, and lymph nodes. Oral B[a]p induced a dose-related decrease in thymus weight (at 10, 30, and 90-mg/kg). Lymph node weights (popliteal, mandibular, and mesenteric) were decreased in the 90-mg/kg rats only. Histologically, indications for cortical atrophy were noted in the thymuses of the 30- and 90-mg/kg dose groups, which was confirmed by morphometric analysis. Nucleated spleen and bone marrow cell counts were decreased in the 90-mg/kg group. Both the absolute number (90 mg/kg) and relative number (10, 30, and 90 mg/kg) of B cells in the spleen were decreased. Red blood cell (RBC) and white blood cell (WBC) counts were significantly decreased; for the WBC at 90 mg/kg, and for the RBC at 10, 30, and 90 mg/kg. The absolute number of lymphocytes and eosinophilic granulocytes was decreased in the 90-mg/kg group, while the absolute number of monocytes was increased in the 10- and 30-mg/kg dose groups. Serum immunoglobulin levels showed a decrease of IgM and IgA after treatment of the animals with 30 and 90 mg/kg, respectively. The highest dose of B[a]p treatment (90 mg/kg) resulted in a significant decrease of natural killer (NK)-cell activity in the spleen. Most toxic effects were only observed in the highest-dose group (90 mg/kg), but compared to the general toxicity, some parameters indicating immunotoxic effects were also affected at lower doses (10 and 30 mg/kg). In conclusion, immunotoxicity of B[a]p can be detected using parameters of the immune system such as described in the recently updated OECD 407 guideline. In the present study thymus weight changed and spleen B-cell populations were affected at a dose of 10 mg/kg, a level where no overt general toxicity was noted.     

Quantification of phencyclidine in mainstream smoke and identification of phenylcyclohex-1-ene as pyrolysis product

Parsley cigarettes containing [3H]phencyclidine were machine smoked, and the mainstream smoke was trapped in glass wool filters. Radioactivity was extracted from these filters with chloroform. The average recoveries of radioactivity were 76, 85, 70, and 69% for cigarettes containing 3, 10, 30, and 50 mg of [3H]phencyclidine hydrochloride, respectively. TLC and GLC-mass spectrometry were employed to identify and quantify compounds in the filter extracts. Approximately one-half of the recovered radioactivity represented a pyrolysis product, phenylcyclohex-1-ene. Formation of this product involved loss of piperidine from phencyclidine. Piperidine, which was not radiolabeled, also may appear in smoke intact. The remainder of the radiolabeled material represented unchanged phencyclidine. Therefore, the percentage of [3H]phencyclidine delivered was approximately 40% of the amount smoked. This result was independent of puff frequency and quantity of phencyclidine hydrochloride smoked over the range tested. The [3H]phencyclidine delivery was compared to the quantities of [3H]-delta 9-tetrahydrocannabinol and [3H]nicotine delivered in mainstream smoke. The recovery of unchanged [3H]-delta 9-tetrahydrocannabinol from placebo marijuana cigarettes injected with a solution containing 3 mg of delta 9-tetrahydrocannabinol was 60%. Tobacco cigarettes injected with [3H]nicotine yielded 70% unchanged nicotine in mainstream smoke.