PCNA在口腔鳞癌中的表达及其临床意义

目的了解增殖细胞核抗原(PCNA)在评估口腔鳞癌组织学分级、肿瘤浸润及转移等生物学特性中的临床意义。方法采用免疫组化SP法测定14例口腔鳞癌和4例正常口腔黏膜标本中的PCNA。结果正常口腔黏膜中PCNA仅在基底细胞层有少量表达，癌组织中PCNA的表达率为100％，其表达强度与病理分级呈正相关(P=0．006)。结论PCNA的表达可作为临床上评估口腔鳞癌生物学特性和预后的参考指标。     

增殖细胞核抗原(PCNA)在甲状腺癌中的表达及意义

目的研究PCNA在甲状腺癌组织、甲状腺良性肿瘤组织及癌旁组织中的表达,并与甲状腺癌患者的年龄、临床分期及淋巴结转移与否等进行比较,探讨其与甲状腺癌侵袭/转移的关系。方法应用免疫组化的方法检测25例甲状腺癌组织、17例癌旁组织及26例甲状腺良性肿瘤组织中PCNA的表达情况,并对数据进行分析。结果 PCNA蛋白在甲状腺癌组织、癌旁组织及甲状腺良性肿瘤组织中的表达率分别为68.00%、23.53%和19.23%,经统计学分析,PNCA蛋白在甲状腺癌与癌旁组织(P=0.029)、甲状腺癌与甲状腺良性肿瘤组织(P=0.018)之间的表达率差异有显著性差异,而癌旁组织与良性肿瘤组织之间无显著性差异(P>0.05)。PCNA蛋白在Ⅰ期+Ⅱ期、Ⅲ期+Ⅳ期患者中的表达率分别为42.86%、100%,经统计学分析,两组间的表达率有统计学差异(P=0.021)。PCNA蛋白在伴淋巴结转移及无淋巴结转移的甲状腺癌组织中的表达率分别为83.33%及28.57%,两者有显著性差异(P=0.011)。结论 PCNA在甲状腺癌中的表达率明显高于癌旁组织及甲状腺良性肿瘤组织;PCNA的表达与甲状腺癌的临床分期关系密切,临床分期越晚,PCNA的表达率越高。伴淋巴结转移甲状腺癌PCNA表达率高于无淋巴结转移者。     

E-cad和PCNA在膀胱肿瘤中的表达及其意义

目的探讨上皮钙依赖黏附蛋白（E-cad）和增殖细胞核抗原（PCNA）在膀胱肿瘤中的表达及其意义。方法采用免疫组化SP法检测1995～2010年76例膀胱恶性肿瘤和12例良性肿瘤,计算每例切片中癌细胞E-cad的异常表达率及增殖细胞核抗原阳性指数（PLI）。结果 E-cad在76例膀胱恶性肿瘤和12例膀胱良性肿瘤中异常表达率分别为84.2%、16.7%,差异有统计学意义（P〈0.05）。膀胱良、恶性肿瘤中PLI增殖指数分别为（35.85±8.20）%、（80.24±19.52）%,差异有统计学意义（P〈0.05）。两者在膀胱恶性肿瘤中表达呈正相关（P〈0.05）。结论 E-cad与膀胱恶性肿瘤的浸润、转移有关,可作为预测转移潜能的指标,PCNA可作为恶性肿瘤增殖的指标。     

核因子-κB、增殖性细胞核抗原在宫颈癌组织中的表达及意义

目的探讨核因子-κB（NF-κB）、增殖性细胞核抗原（PCNA）在宫颈癌组织中的表达及其意义。方法采用免疫组织化学方法,检测45例宫颈癌组织及30例正常宫颈组织中NF—κBp65、PCNA的表达。结果宫颈癌组织中NF-κBp65、PCNA表达率均明显高于正常组织（P〈0．05）。Ⅰb、Ⅱa期宫颈癌组织NF—κBp65、PCNA表达明显高于Ⅰa期宫颈癌组织（P〈0．05）,低分化者表达明显高于中、高分化者（P〈0．05）,有淋巴结转移者明显高于无淋巴结转移者（P〈0．05）;且NF-κBp65与PCNA的表达呈正相关（r=0．705,P〈0．05）。结论NF-κB、PCNA与宫颈癌的发病、侵袭和转移密切相关。     

人肾透明细胞癌组织中增殖细胞核抗原表达与肾癌的关系

目的 通过检测人肾透明细胞癌组织中增殖细胞核抗原（PCNA）表达的变化,研究其表达与肾癌的关系.方法 标本离体后分成肾透明细胞癌组、癌旁组织组、正常肾组织组,均用10%的甲醛固定48 h,常规石蜡包埋、切片5 μm,同时应用免疫组织化学方法进行观察研究.结果 PCNA免疫组化染色：正常肾组织内的细胞核有弱阳性表达,癌旁阳性表达增加,高于正常肾组织,肾癌组织阳性表达明显增强, 明显高于癌旁组织,两两比较差异均有统计学意义（P＜0.01）.肾癌4个期之间比较差异无统计学意义（P＞0.05）.结论 PCNA在正常组、癌旁组、癌组织组的表达呈明显加强趋势,癌组织细胞增殖旺盛,是肿瘤形成的重要机制.     

肝细胞癌组织中环氧化酶2与增殖性细胞核抗原的表达及相关性

目的 观察环氧化酶2(COX-2)和增殖性细胞核抗原(PCNA)在肝细胞癌组织中的表达及相关性.方法 应用免疫组化法检测肝细胞癌组织COX-2与PCNA蛋白的表达,并对阳性结果进行图像分析.结果 肝癌组织和癌旁组织中COX-2、PCNA阳性表达率及其阳性面积百分比差异均有统计学意义(P＜0.05).COX-2阳性组和COX-2阴性组中PCNA阳性表达率之间差异有统计学意义(P＜0.05).肝癌组织和癌旁组织中COX-2阳性表达面积百分比与PCNA阳性表达面积百分比之间有相关性.结论 肝细胞癌组织存在COX-2过度表达,且与PCNA表达水平有相关性.     

胃癌p53蛋白与PCNA的免疫组织化学研究

目的　探讨p53蛋白及PCNA与胃癌发生、发展的关系。方法　对39例进展期胃癌手术标本的肉眼可见的肿瘤组织、癌旁2cm处及切缘“正常”组织进行p53蛋白及PCNA免疫组化检则。结果　切缘“正常”组织、癌旁及胃癌组织均有不同程度p53蛋白和PCNA的表达,p53阳性率逐渐升高,分别为10.3%(4/39)、28.2%(11/39)及59.0%(23/39),PCNA分级也逐渐升高,与p53呈正相关(P<0.05)。p53蛋白表达与肿瘤的浸润深度、血管和淋巴管浸润及淋巴结转移有关,p53蛋白阳性的胃癌,其细胞增殖活性明显高于阴性者。结论　p53蛋白检测有助于胃粘膜癌变倾向的判断和胃癌的早期诊断,对癌前病变的研究和手术切缘的评估有一定意义。联合检测p53和PCNA对胃癌恶性程度的判断有较高的价值。     

Antigenotoxic effect of Saccharomyces cerevisiae on the damage produced in mice fed with aflatoxin B1 contaminated corn

The potential of Saccharomyces cerevisiae (Sc) was evaluated for reducing the micronucleated normochromatic erythrocytes (MNNE) rate in mice fed AFB₁ contaminated corn. The study included two groups fed AFB₁ contaminated corn (0.4 and 0.8 mg/kg), a control fed uncontaminated corn, another group fed uncontaminated corn and 0.3% of Sc (1 × 10⁸ live cells/g), and two groups fed AFB₁ contaminated corn (0.4 and 0.8 mg/kg) plus 0.3% Sc. Weight and MNNE were determined weekly for six weeks. Subsequently, the same determinations were made for another three-week period, but in mice receiving only a normal diet, without AFB₁ and Sc. Results in the first period revealed the following: control and Sc fed mice had similar constant weight increase, and low MNNE rate; mice fed only AFB₁ showed weight decrease and significant MNNE increase; finally, Sc improved weight gain and reduced MNNE produced by AFB₁. In the second period, results exhibited a tendency similar to that of the previous phase in the control and Sc fed mice; the weight and MNNE values improved in the other groups. We also determined the capacity of Sc for adsorbing and modifying the mycotoxin structure. The mixture was filtered to obtain two phases, and AFB₁ content was measured. Sc revealed a potent adsorbent capacity; however, chromatographic determination suggested no structural modification.     

增殖细胞核抗原、表皮生长因子受体和B淋巴细胞瘤基因在非小细胞肺癌中的表达及临床意义

目的研究增殖细胞核抗原（PCNA）、表皮生长因子受体（EGFR）和B淋巴细胞瘤基因（BCL-2）3种基因蛋白与非小细胞肺癌（NSCLC）临床病理特征的关系。方法应用S-P免疫组化法检测44倒手术切除NSCLC标本中3种基因蛋白的表达。结果44例标本中37例（84．09％）PCNA过度表达，30例（68．18％）EGFR过度表达，19例（43．18％）BCL-2过度表达。PCNA、EGFR及BCL-2阳性表达率在NSCLC淋巴结有元转移患者间均有统计学意义（P〈0．01或P〈0．05）。PCNA和EGFR阳性表达率与患者生存时间长短组间有统计学意义（P〈0．01或P〈0．05）。但是3种蛋白阳性表达率均与肿瘤大小、分化程度无相关性（P〉0．05）。结论PCNA、EGFR和BCL-2基因过度表达可能与NSCLC的转移、预后有关。     

细胞凋亡及增殖细胞核抗原在肝癌组织中的表达及意义

目的探讨经肝动脉化疗栓塞(TACE)后肝癌细胞中增殖细胞核抗原(PCNA)广凋亡细胞比值与肝细胞肝癌分化程度的关系。方法应用原位末端标记法(TUNEL)及免疫组化双染色技术，对60例肝细胞肝癌石蜡包埋组织进行检测。结果不同分化程度癌组织中细胞凋亡和PCNA的阳性率不同。分化程度高，细胞凋亡阳性率高、PCNA阳性率偏低；分化程度低，细胞凋亡阳性率偏低、PCNA阳性率高。随分化程度的降低，PCNA广凋亡细胞的比值显著增加，两者有相关性。结论PCNA/凋亡细胞的比值可作为评估肝细胞肝癌分化程度的指标。     

扁平苔癣皮损区c-myc PCNA VEGF的表达研究

目的探讨原癌基因c-myc、增殖细胞核抗原(PCNA)、血管内皮细胞生长因子(VEGF)在扁平苔癣发病中的作用。方法采用免疫组织化学方法,检测了60例扁平苔癣皮损区及60名健康志愿者的表皮中c-myc、PCNA、VEGF的表达及分布特点。结果扁平苔癣皮损区c-myc、PCNA、VEGF表达均较正常表皮中的表达明显增强,分布于除角质层以外的表皮各层,而正常表皮表达阴性或仅在基底层有弱阳性表达。结论c-myc、PCNA在扁平苔癣皮损中过度表达,提示其与扁平苔癣的表皮细胞过度增殖、分化异常有关;VEGF过度表达,提示VEGF与扁平苔癣的真皮浅层淋巴细胞浸润有关。     

Activity of some respiratory enzymes and cytochrome contents in rat hepatic mitochondria following aflatoxin B1 administration

Effects of aflatoxin B₁ (AFB₁) administration (7 mg/kg body weight i.p.) on rat hepatic mitochondrial respiratory components have been examined. Succinoxidase and cytochrome oxidase activities were decreased in liver mitochondria isolated from rats 12–24 h after AFB₁ treatment. Both enzyme activities returned to normal levels after 48 h. Glutamate dehydrogenase and β-hydroxybutyrate dehydrogenase activities did not show any alterations up to 24 h and thereafter increased at 48–72 h. Succinate dehydrogenase activity was impaired by 41% at 12 h and thereafter was found to be normal. The intramitochondrial cytochrome b content declined at 24–72 h, whereas cytochrome aa₃ content was decreased maximally at 72 h after AFB₁ administration. These observations on mitochondrial enzyme activities and cytochrome contents correlate well with our earlier observations made on hepatic mitochondrial respiratory rates after AFB₁ treatment. The impairment of respiratory functions possibly results from membrane damage and selective modification of gene expression in mitochondria imparted by AFB₁.     

脑膜瘤雄激素受体表达与细胞增殖和临床病理的关系

目的　探讨脑膜瘤雄激素受体 (AR)表达与肿瘤细胞增殖和临床病理的关系。方法　采用SABC免疫组织化学方法检测 5 0例脑膜瘤组织中AR和增殖细胞核抗原 (PCNA)的表达 ,分析其与临床病理的关系。结果　良性、非典型性、恶性脑膜瘤组织中AR阳性表达率分别为 2 9 2 % (8/ 2 4 )、5 6 3% (9/ 16 )、80 0 % (8/ 10 )。恶性脑膜瘤AR阳性表达率显著高于非典型性和良性脑膜瘤 (P <0 0 5 )。AR阳性脑膜瘤PCNA标记指数 (LI)显著高于AR阴性脑膜瘤 (P <0 0 1) ,脑膜瘤AR表达与PCNA表达呈正相关。结论　AR过度表达与脑膜瘤细胞的异常增殖和病理级别有关 ,在脑膜瘤的发生发展过程中起重要作用     

Metabolism of aflatoxin B1 (AFB1), aflatoxin G1 (AFG1) and vitamin C intake by guinea pig liver preparation in vitro

Male and female guinea pigs weighing 150–200 g were divided into three groups, with equal number of males and females in each group. They were fed an experimental diet which varied as follows: group I, 0 mg vitamin C/g of diet; group II, 1.08 mg/g and group III, 5.4 mg/g, for 28 days. Twenty-four hours after the last feeding, liver slices and 9000 g supernatant were prepared from each group, according to sex, and used for enzyme assays. For the demethylation assay, enzyme activity expressed as amount of formaldehyde produced from AFB₁, or AFG₁/hr/g fresh liver was seen to increase with the two levels of ascorbic acid intake in females. Males showed an enhancement of activity only in group II and remained with the same production of formaldehyde as above in group III. Although in each dietary group, the activity was higher in males than in females the variation in the amount of formaldehyde produced from one group to another was higher with females than with male guinea pigs. However with both sexes, the production of formaldehyde from AFG₁, was greater than from AFB₁. For the hydroxylation assay, enzyme activity was expressed as amount of metabolites (a) and (b) produced. Compared to group II, which offered a control level of ascorbic acid, group I fed without vitamin C showed a decreased production of metabolite (a) and (b) with males and females. Moreover, high intake of ascorbic acid in group III decreased the production of metabolite (a) and (b) in males, while in female guinea pigs the reduction was observed only with (b).     

Up-regulation of nucleotide excision repair in mouse lung and liver following chronic exposure to aflatoxin B1 and its dependence on p53 genotype

Aflatoxin B₁ (AFB₁) is biotransformed in vivo into an epoxide metabolite that forms DNA adducts that may induce cancer if not repaired. p53 is a tumor suppressor gene implicated in the regulation of global nucleotide excision repair (NER). Male heterozygous p53 knockout (B6.129-Trp53^tm1BrdN5, Taconic) and wild-type mice were exposed to 0, 0.2 or 1.0 ppm AFB₁ for 26 weeks. NER activity was assessed with an in vitro assay, using AFB₁-epoxide adducted plasmid DNA as a substrate. For wild-type mice, repair of AFB₁–N7-Gua adducts was 124% and 96% greater in lung extracts from mice exposed to 0.2 ppm and 1.0 ppm AFB₁ respectively, and 224% greater in liver extracts from mice exposed to 0.2 ppm AFB₁ (p < 0.05). In heterozygous p53 knockout mice, repair of AFB₁–N7-Gua was only 45% greater in lung extracts from mice exposed to 0.2 ppm AFB₁ (p < 0.05), and no effect was observed in lung extracts from mice treated with 1.0 ppm AFB₁ or in liver extracts from mice treated with either AFB₁ concentration. p53 genotype did not affect basal levels of repair. AFB₁ exposure did not alter repair of AFB₁-derived formamidopyrimidine adducts in lung or liver extracts of either mouse genotype nor did it affect XPA or XPB protein levels. In summary, chronic exposure to AFB₁ increased NER activity in wild-type mice, and this response was diminished in heterozygous p53 knockout mice, indicating that loss of one allele of p53 limits the ability of NER to be up-regulated in response to DNA damage.     

A clonal cell line (BME-UV1) as a possible model to study bovine mammary epithelial metabolism: metabolism and cytotoxicity of aflatoxin B1

Despite the toxicological risks to which humans and animals are exposed due to the transfer of toxic xenobiotic metabolites into milk of domestic animals, studies on the metabolizing mechanisms occurring in ruminant mammary gland are totally lacking. To investigate the possible biotransformation capabilities of a bovine mammary epithelial cell line (BME-UV1), monolayers were exposed to aflatoxin B1 (AFB1 - 1.0-8.0 μM). Starting from 4 h of exposure, the hydroxylate metabolite aflatoxin M1 (AFM1) was detected in media by high performance liquid chromatography. AFM1 concentration increased linearly with time for 36-48 h and the percent biotransformation of AFB1 (2-4 μM) at 48 h was about 12-14%. Parallel cytotoxicity assays (neutral red uptake-NRU and MTT assays) were performed to investigate the possible interference of AFB1 cytotoxicity with cellular metabolism. MTT assay (from 24 h of cell exposure) and NRU assay (from 16 h of cell exposure) showed time-dependent and time/concentration-dependent decrease of cell viability, respectively, and the former assay being more successful at revealing cytotoxic effects (NRU: CC₅₀ at 48 h = 12.00 ± 2.66 μM; MTT: CC₅₀ at 72 h = 20.42 ± 7.30 μM). The results suggest that BME-UV1 cells express metabolizing enzymes having catalytic activity, thus representing a potential in vitro model for studying biotransformation in bovine mammary gland.     

Toxicity,biochemical effects and residue of aflatoxin B1 in marine water-reared sea bass (Dicentrarchus labrax L.)

Aflatoxicosis and resulting epizootic hepatoma have been reported among a wide range of fish where Aspergillus species-contaminated foodstuffs are incorporated into the diet. Aflatoxin B₁ (AFB₁) is among the most potent known hepatotoxins and carcinogens. Therefore, it is an important potential toxicant to the most of the popularly cultured fish species. The present study was undertaken to assess the susceptibility and toxicity of AFB₁ to sea bass (Dicentrarchus labrax L.), by behavioral and biochemical evaluations. The estimated oral acute median lethal concentration (96 h LC₅₀) of AFB₁ for sea bass was 0.18 mg/kg bwt. The abnormal behavioral responses and signs of toxicity were described. The prolonged oral administration of 0.018 mg/kg bwt AFB₁ to sea bass for 42 successive days induced a significant increase in serum transaminases and alkaline phosphatase activities, and significant decrease in plasma proteins. Residual AFB₁ was detected at high levels (≈5 ppb) in fish musculature at the end of the experimental period. We conclude that marine water sea bass is a species highly sensitive to AFB₁. In addition, consumption of sea bass reared on AFB₁-contaminated diet could have a negative health impact on human health.     

Fumonisin B1 and the kidney: Modes of action for renal tumor formation by fumonisin B1 in rodents

The mycotoxin fumonisin B₁ (FB₁) is an important contaminant of maize and maize-based products. In rodent toxicity studies, FB₁ was shown to be hepato- and nephrotoxic, and to induce renal tumors in rats when administered via the diet. Of particular note are the aggressive growth characteristics of FB₁-induced tumors with a high potential to metastasize. While genotoxicity does not appear to contribute to FB₁ carcinogenicity, it is well established that FB₁-mediated disruption of sphingolipid metabolism plays a key role in FB₁ toxicity. This review provides an overview on human dietary exposure to FB₁, FB₁ toxicity and carcinogenicity, and potential mechanisms involved in FB₁-mediated tumor formation, with a particular focus on cellular functions of sphingolipids and biological consequences of FB₁-mediated perturbation of sphingolipid metabolism.     

不同来源甲硫氨酸维B1注射剂体外细胞毒性的比较与分析

目的：比较不同来源甲硫氨酸维B₁注射剂体外细胞毒性的差别并寻找差别形成的主要原因。方法：将不同来源甲硫氨酸维B₁注射剂不同浓度的稀释液与小鼠成纤维细胞L-929接触培养,通过倒置相差显微镜观察细胞形态,采用四甲基偶氮唑盐比色法（MTT法）量化细胞毒性,计算相对增殖率,并进行细胞毒性评价。建立甲硫氨酸维B₁注射剂中枸橼酸含量的高效液相色谱检测方法,考察枸橼酸含量与制剂细胞毒性的相关性。结果：7个生产厂家的甲硫氨酸维B₁注射液细胞毒性无明显差别。12个生产厂家的注射用甲硫氨酸维B₁中有11个厂家的样品不同浓度组对L-929的细胞毒性级别为1级或2级。但J厂家的注射用甲硫氨酸维B₁样品（20 mg·mL^-1和10 mg·mL^-1）对L-929的细胞毒性级别为4级,表现为重度毒性。枸橼酸质量浓度3,1.5,0.75 mg·mL^-1的相对增殖率分别为7%、45%、74%,而对应的含等量枸橼酸的制剂浓度（以甲硫氨酸计）20,10,5 mg·mL^-1的相对增殖率分别为6%、28%、53%,细胞毒性试验结果吻合。结论：不同厂家生产的甲硫氨酸维B₁注射剂由于处方工艺不同等,其细胞毒性存在差别。枸橼酸作为注射剂的常用辅料,在高于0.188 mg·mL^-1的浓度下存在细胞毒性,枸橼酸含量与细胞毒性呈正相关性,J厂家样品的重度细胞毒性可能主要源于过高浓度的辅料枸橼酸。建议生产厂家降低枸橼酸添加量,以减少制剂的细胞毒性,提高药品的安全性。