4种药物干预治疗骨质疏松模型大鼠骨三点弯曲力学特性的对比分析

背景：力学性能指标是评价药物治疗骨质疏松动物模型效果的重要方法,以3点弯曲力学性能指标评价多种药物治疗老龄雌性骨质疏松模型动物的效果鲜有报道。 目的：以大鼠骨3点弯曲力学性能指标评价骨质疏松模型大鼠经丹杞颗粒、结合性雌激素、依普拉芬及αD3干预的效果。 方法：Wistar雌性大鼠48只分为6组,除正常组外,采用以去双侧卵巢的方法复制老龄骨质疏松大鼠模型。丹杞颗粒干预组每日给服丹杞颗粒0.9 g/kg,普拉芬干预组每日给服依普拉芬1 mg/kg,αD3干预组每日给服αD3 0.1 mg/kg,结合型雌激素干预组每日给服结合型雌激素0.3 mg/kg。以电子万能实验机对各组大鼠左、右侧胫骨进行3点弯曲力学性能测试。 结果与结论：丹杞颗粒、依普拉芬、结合型雌激素干预组胫骨最大载荷、最大应力、最大弯矩、最大应力及弹性模量大于模型组(P < 0.05);αD3干预组最大载荷、最大应力、最大应变、弹性模量与模型组差异无显著性意义(P > 0.05);丹杞颗粒干预组胫骨最大载荷、最大应力、最大应变与正常对照组比较差异无显著性意义(P > 0.05)。丹杞颗粒干预组、结合型雌激素干预组、依普拉芬干预组弯曲力学性能恢复较好,以丹杞颗粒干预组效果最好,αD3干预治疗组弯曲力学性能指标无明显恢复。结果说明以丹杞颗粒干预骨质疏松模型大鼠胫骨3点弯曲力学性能恢复效果最好。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

几种药物干预骨质疏松动物模型骨剪切力学特性的对比分析

对正常对照组、骨质疏松模型组,以丹杞颗粒、依普拉芬、结合型雌激素、倍美力、阿法D3治疗组大鼠胫骨进行剪切力学特性测试,确定各种药物治疗骨质疏松的效果。以去卵巢法复制老龄骨质疏松动物模型,以丹杞颗粒、依普拉芬、结合性雌激素（倍美力）、αD3进行治疗,饲养15周后取大鼠左、右侧胫骨进行剪切实验。结果表明,骨质疏松动物模型组股骨最大载荷、最大剪切应力,显著低于正常对照组和各治疗组（P＜0．05）,最大应变与αD3组差异不显著（P＞0．05）。以丹杞颗粒治疗组大鼠胫骨最大载荷、最大剪切应力、最大剪切应变与正常的对照组大鼠胫骨最大载荷、最大剪切应力、最大剪切应变差异不显著（P＞0．05）。模型组大鼠由于骨质疏松导致胫骨剪切力学特性发生改变。以丹杞颗粒、依普拉芬、结合型雌激素（倍美力）治疗组剪切力学特性均有一定提高,丹杞颗粒效果最好,αD3组剪切力学性能提高不显著。     

骨质疏松动物模型骨的拉伸、压缩、扭转实验研究

研究了正常大鼠和去势所致大鼠骨质疏松以电针、灸法、电针加雌激素、灸法加雌激素治疗组大鼠骨的拉伸、压缩、扭转力学性质。选用36只280～320g，4～5月龄Wistar雌性大鼠，随机分为正常对照组6只，模型组6只，电针治疗组6只，灸法治疗组6只，电针加雌激素治疗组6只，灸法加雌激素治疗组6只，对模型组大鼠于0周摘除其卵巢。对正常对照组和模型组大鼠饲养13周后，以腹主动脉放血法处死大鼠，取大鼠肱骨进行拉伸实验，取大鼠股骨进行扭转实验，取大鼠胫骨进行压缩实验。得出了各组大鼠骨的拉伸、压缩应力、应变、弹性模量、扭转剪应力、扭转角等指标。结果表明：模型组拉伸、扭转、压缩力学性能指标均小于正常组．     

几种药物干预骨质疏松模型大鼠股骨的剪切力学特性

背景：剪切力学性能指标是对药物治疗后骨质疏松质量评价的一种可靠方法。 目的：建立骨质疏松动物模型,比较不同药物干预骨质疏松模型大鼠后的剪切力学性能变化。 方法：将60只大鼠分别设为正常对照组 10只,其余50只去除双侧卵巢法复制骨质疏松动物模型,再随机分为5组：模型组不用药,复方中药组大鼠每日给服中药0.9 g/kg、阿仑膦酸钠组大鼠每日给服阿仑膦酸钠1 mg/kg、维生素K组大鼠每日给服维生素K 0.1 mg/kg、钙剂组大鼠每日给服逸得乐2 mg/kg。各组大鼠股骨在电子万能试验机上进行剪切力实验。 结果与结论：正常对照组、复方中药组、阿仑膦酸钠组、维生素K组大鼠股骨最大剪切力、最大剪应力均显著高于模型组(P < 0.05)。钙剂组大鼠最大剪切力、最大剪应力与模型组比较差异无显著性意义。复方中药组大鼠最大剪切力、最大剪应力与正常对照组比较,差异无显著性意义。提示：中药、西药、维生素K治疗动物骨质疏松模型大鼠均有一定疗效,钙剂效果不明显,中药的效果最好。     

药物治疗骨质疏松肱骨拉伸力学特性的对比

背景：力学性能指标是评价药物治疗骨质疏松动物模型效果的重要方法,以拉伸力学性能指标评价多种药物治疗老龄雌性骨质疏松模型大鼠的效果评价罕见报道。 目的：评定中药骨疏康胶囊、西药阿仑膦酸钠、维生素K、钙剂逸得乐对骨质疏松模型大鼠肱骨拉伸力学的影响。 方法：四五个月龄雌性Wistar大鼠180只分为6组,每组30只。除正常对照组外对所有大鼠于0周摘除双侧卵巢制备骨质疏松动物模型。骨疏康胶囊组动物每日给服骨疏康胶囊0.9 g/kg、阿仑膦酸钠治疗组动物每日给服阿仑膦酸钠1 mg/kg、维生素K组动物每日给服维生素K 0.1 mg/kg、钙剂组动物每日给服钙剂逸得乐2 mg/kg。15周后取大鼠左、右侧肱骨在电子万能试验机上以5 mm/min的实验速度进行拉伸实验,试样破坏后观察试样的断口形貌。 结果与结论：骨质疏松动物模型组大鼠肱骨拉伸实验最大载荷、最大应变显著小于正常对照组和骨疏康胶囊组、阿仑膦酸钠组、维生素K组(P < 0.05);钙剂组最大载荷,最大应力,最大应变和模型组差异不显著(P > 0.05)。结果说明,中药、西药、维生素K治疗骨质疏松模型大鼠拉伸力学性能均有一定提高,中药骨疏康胶囊治疗骨质疏松模型大鼠拉伸力学性能明显提高。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

模拟雄性大鼠老龄骨质疏松力学性质实验研究

研究了正常与老龄骨质疏松(雄性)大鼠骨的力学性质.选用280～360g、5～6个月龄Wistar雄性大鼠40只,随机分为正常对照组20只,骨质疏松模型组20只.对模型组大鼠于0周摘除睾丸,对照组与模型组大鼠饲养14周后,以腹主动脉放血法处死大鼠.取大鼠肱骨进行拉伸、压缩实验,取大鼠股骨进行弯曲、剪切实验,取大鼠胫骨进行扭转、冲击实验.大鼠肱骨拉伸、压缩最大载荷、最大应力、最大位移、最大应变及弹性模量,得出了正常对照组和模型组大鼠股骨三点弯曲最大载荷、最大弯矩、最大应力、弹性模量及剪切最大载荷、最大应力,得出了正常对照组和模型组大鼠胫骨扭转最大扭矩、扭转角、扭转剪应力、最大冲击功、冲击韧性指标,并对实验结果进行分析讨论.     

去势大鼠骨形态计量学、生物性能变化

目的 通过观察大鼠血清学、骨形态计量学测定、骨生物性能等方法研究去卵巢大鼠骨变化.方法 采用7-12月龄SD雌性大鼠30只,随机分为对照组、模型组和尼尔雌醇组.模型组和尼尔雌醇组大鼠切除双侧卵巢进行造模.尼尔雌醇组大鼠造模后45天开始灌服尼尔雌醇,连续90天;对照组和模型组大鼠手术后第45天开始灌服去离子水,连续90天.所有大鼠给药第80、87天时两次ip四环素20mg/kg进行骨荧光标记.实验结束时,取出大鼠股骨及第四腰椎骨进行股骨形态计量学测定、股骨骨密度测量、股骨三点弯曲实验及椎骨压缩实验,同时测定血清碱性磷酸酶(ALP)、抗酒石酸酸性磷酸酶(StrACP)水平.结果 大鼠去双侧卵巢后,股骨骨密度、骨最大载荷、最大应力、弹性模量、刚度水平和骨小梁体积显著性提高;椎体压缩性能、股骨形态计量学、股骨弯曲性能有明显改变;而雌激素对以上变化有不同程度改善作用.结论 骨组织形态、骨生物性能是评价骨质疏松模型或药物疗效的重要指标;发生骨质疏松时,骨组织形态学变化先于骨生物性能变化.     

骨质疏松大鼠股骨骨折骨痂及腰椎的生物力学研究

目的 :探讨骨质疏松大鼠股骨骨折骨痂及腰椎的生物力学。方法 :8月龄雌性Wistar大鼠摘除卵巢 ,3个月后制作左股骨中段骨折克氏针内固定的模型。术后鲑鱼降钙素 (密盖息 )组每天皮下注射密盖息 2IU / 。雌激素组每隔 2d皮下注射苯甲酸雌二醇 0 .1mg/ 。另设假手术组和骨质疏松组对照。8周后处死大鼠 ,左股骨行扭转实验 ;第 4腰椎行凹入实验。结果 :降钙素组 ,雌激素组股骨的最大扭矩 ,扭转刚度和腰椎的最大载荷 ,松质骨刚度都明显高于骨质疏松组 (P <0 .0 5 ) ,与假手术组相似 (P >0 .0 5 )。结论 :鲑鱼降钙素和雌激素能改善骨质疏松大鼠股骨骨痂及腰椎的生物力学性能 ,提高骨质量 ,增强抗骨折能力。     

去势大鼠所致骨质疏松对骨的黏弹性力学性质影响

目的 研究了正常大鼠和去势所致大鼠骨质疏松大鼠骨的应力松弛、蠕变力学性质,为临床提供生物力学参数.方法 选用280～320g,4～5月龄Wistar雌性大鼠50只,随机分为正常对照组25只,模型组25只.对模型组大鼠于0周摘除其卵巢.对正常对照组和模型组大鼠饲养14周后,以腹主动脉放血法处死大鼠,取大鼠股骨进行压缩试验,取大鼠胫骨进行冲击试验,还取大鼠股骨进行压缩应力松弛、蠕变实验.结果 得出了大鼠股骨压缩力学性能指标和大鼠胫骨冲击力学性能指标,得出了正常组和模型组大鼠股骨应力松弛、蠕变实验数据和曲线,对应力松弛、蠕变实验数据进行归一化处理,得出了归一化应力松弛函数,归一化蠕变函数及曲线.对实验数据进行同归分析,得出了同归系数和G(t)、J(t)表达式.结论 模型组压缩和冲击力学性能指标和7200s应力松弛量、蠕变量均小于正常组.     

骨质疏松对骨生物力学性质影响实验研究

研究了正常大鼠股骨和维甲酸所致大鼠骨质疏松股骨的生物力学性质。选用了 175 g～ 2 4 5 g ,3月龄～ 4月龄Wistar大鼠 6 0只 ,随机分为正常对照组 30只 ,模型组 30只。对模型组大鼠灌服维甲酸 (70mg·kg-1·d-1) 2周 ,实验第 12周末处死大鼠 ,测定股骨骨密度。取胫骨制作脱钙切片 ,进行骨组织形态观察。取股骨进行拉伸、冲击实验和应力松弛、蠕变实验。测定股骨生物力学性能指标 ,得出了正常对照组和模型组股骨的拉伸应力、应变数据等。还得出冲击功、冲击韧性、应力松弛 ,蠕变数据和曲线。对应力松弛蠕变实验数据进行归一化处理 ,得出归一化应力松弛函数、蠕变函数及曲线。实验结果表明模型组的各项力学性能指标显著低于正常对照组 (P <0 .0 5 )。对骨质疏松对力学性能指标的影响进行分析讨论。     

Association of parental consanguinity with decreased birth weight and increased rate of early death and congenital malformations

Data on parental consanguinity have been recorded for all births in Norway since 1967. Pregnancy outcome for offspring of 848 women mated to their first cousins were compared with offspring of 1,696 control women. The stillbirth rate was 23.6 per thousand for cases and 13.4 for controls. The neonatal death rate was 34.9 per thousand for cases and 14.3 for controls. The recurrence risk for sibs for early death was 9.4% for cases and 4.2% for controls. The mean offspring birth weight was significantly lower (3377 g vs. 3491 g), and the variance in birth weight was slightly larger for cases than controls. The percentage of children with malformations detected shortly after birth was 4.6% for cases and 2.2% for controls. The differences may be attributed to the increased homozygosity in offspring of first cousins. The results have relevance for genetic counselling to consanguineous couples, as well as for the understanding of the etiology of adverse pregnancy outcome and for elucidating the causes of variation in birth weight.     

Immunohistochemical marker panels for distinguishing between epithelioid mesothelioma and lung adenocarcinoma

The distinction between epithelioid mesothelioma and lung adenocarcinoma remains an important diagnostic challenge for surgical pathologists. The aim of the present study was to select a limited and appropriate panel of antibodies that can differentiate between epithelioid mesothelioma and lung adenocarcinoma. Specimens of 90 epithelioid mesotheliomas and 51 lung adenocarcinomas obtained from Japanese cases were examined using calretinin, WT1, AE1/AE3, CAM5.2, cytokeratin (CK) 5/6, vimentin, epithelial membrane antigen (EMA), thrombomodulin, CEA, CA19-9, and CA125. Ninety-six percent of epithelioid mesotheliomas were positive for calretinin; 99% for WT1; 100% for AE1/AE; 97% for CAM5.2; 70% for CK 5/6; 91% for vimentin; 96% for EMA; 71% for thrombomodulin; 77% for mesothelin; 7% for CEA; 17% for CA19-9; and 85% for CA125. In contrast, 33% of lung adenocarcinomas were positive for calretinin; 16% for WT1; 100% for AE1/AE3, CAM5.2, and EMA; 41% for CK 5/6; 47% for vimentin; 20% for thrombomodulin; 69% for mesothelin; 98% for CEA; 73% for CA19-9; and 80% for CA125. For distinguishing between epithelioid mesothelioma and lung adenocarcinoma, the combination of CEA, calretinin and each WT1 or thrombomodulin was suggested to be the best panel of immunohistochemical markers.     

Immunocytochemical characterization of neuroendocrine tumours of the larynx

Twenty-two neuroendocrine tumours of the larynx were investigated using a panel of immunocytochemical markers. Three were small cell carcinomas, eight were large cell neuroendocrine carcinomas and 11 were paragangliomas. Twenty were positive for protein gene product 9.5, 19 for neuron-specific enolase, 15 for chromogranin A, nine for bombesin, eight for substance P, eight for neuropeptide Y, eight for metenkephalin, seven for somatostatin, five for calcitonin, eight for calcitonin gene-related peptide and one for vasoactive intestinal polypeptide. Bombesin immunoreactivity was largely restricted to the small cell carcinomas and large cell neuroendocrine carcinomas and neuropeptide Y, metenkephalin and substance P to the parangangliomas. This comprehensive immunocytochemical analysis of neuroendocrine tumours of the larynx demonstrates that these tumours represent special entities but have similar patterns of immunostaining to those of neuroendocrine tumours in other sites.     

1307例育龄妇女血清TORCH抗体定量检测结果分析

目的 了解昆明地区育龄妇女弓形虫（TOX）、风疹病毒（RV）、巨细胞病毒（CMV）、单纯疱疹病毒（ HSV）,总称为TORCH的感染状况,为预防妊娠TORCH感染、降低新生儿出生缺陷发生率提供参考资料。方法 采用德国virion/serion酶联免疫吸附试验（ELISA）定量试剂,对1307例育龄妇女血清TORCH感染特异性IgM及IgG抗体进行检测,并对其结果进行分析。结果 1307例育龄妇女TORCH感染特异性IgM抗体总阳性率为1.45％,其中TOX：2.83％;RV：2.37％;CMV：0.46％;HSV：2.45％。特异性IgG抗体总阳性率为63.60％,其中TOX：3.98％;RV：72.30％;CMV：97.78％;HSV：80.34％。不同孕期妇女TORCH感染特异性抗体检出率差异无统计学意义。结论 本次调查中,1307例育龄妇女存在一定比例的TORCH现症感染,建议妊娠妇女尽可能进行TORCH筛查,以便尽早采取相应措施,避免由TORCH感染导致出生缺陷发生。     

100例颅骨视神经管及其周围关系的观察与测量

采用100个颅底(水平锯开颅顶),对视神经管进行测量,全长均值男11.0mm,女10.46mm;眶口的直径均值男4.48mm,女4.92mm;眶口横径均值男4.13mm,女3.38mm.视神经管口前缘点至眼眶前缘上、下、内、外四壁各点的距离均值分别为:男8.87、6.50、8.89、8.82mm;女8.72、6.00、8.22、7.35mm.视神经管眶口内侧缘中点至筛前孔、筛后孔、内眦部眶缘的距离均值分别为男34.4、20.7、43.96mm;女31.42、19.94、42.97mm.颅正中矢状轴与视神经管中轴的夹角均值男37.42度,女36.44度.两侧视神经管眶口均值男29.45mm,女27.51mm.并对眶口和颅口的形态进行了观察和测量.     

韩国人CYP450 1A1、CYP450 2E1和GSTM1、GSTT1、GSTP1基因座遗传多态性分析

目的 调查代谢相关的CYP4501A1、CYP4502E1和GSTM1、GSIT1、GSTP1基因座在韩国人群中的遗传多态性分布状况。方法 采用多重聚合酶链式反应、聚合酶链式反应-限制性片段长度多态性技术，分析300名韩国健康大学生的CYP1A1基因3′端限制性内切酶Msp Ⅰ位点、CYP2E1基因5′端转录调节区Pst Ⅰ位点和GSTM1、GSTT1缺失与存在、GSTP1基因第5外显子BsmA Ⅰ位点的基因型，计算基因型和基因频率。结果 CYP1A1基因型频率为ml／ml型39．7％、ml／m2型49．7％、m2／m2型10．7％，基因频率为ml 0．645、m2 0．355。CYP2E1基因型频率为cl／cl型66．7％、cl／c2型30％、c2／c2型3．3％，基因频率为C1 0．818、C2 0．182。GSTM1基因缺失型频率为53．3％。GSTT1基因缺失型频率为54．7％。GSTP1基因型频率为Ile／Ile型62％、Ile／Val型34．3％、VaL／Val型3．7％，基因频率为Ile 0．792、Val 0．208。基因分布符合Hardy-Weirtberg平衡定律。结论 韩国人CYP1A1、CYP2E1、GSTM1、GSTT1基因分布与我国人群较为相近，半数以上人缺乏GSTM1和GSTT1基因，纯合缺失型频率超过印度人的3倍。     

Of human bondage: food craving,obsession, compulsion,and addiction

Is it more than a linguistic accident that the same term, craving, is used to describe intense desires for both foods and for a variety of drugs of abuse? There is strong evidence for common pathways that are affected by most addictive drugs. As the other contributors to this volume will indicate, a strong case can also be made for some shared substrates for food and drug rewards in animals. There has been less explicit work on this topic in humans but many lines of evidence support the common mechanism view: Opioid peptides seem to influence food palatability for humans. There is mounting evidence for comorbidity between drug/alcohol abuse and excessive craving or liking for sweets. Anecdotally, elderly individuals tend to 'age-out' of drug abuse, and the elderly also experience markedly fewer food cravings with age. If we focus on the compulsive aspects of food and drug cravings, there is also evidence for overlap: for example, activity in the orbitofrontal cortex is associated with cocaine and alcohol craving. This area is also implicated in the pathology of obsessive-compulsive disorder. Although there is no direct evidence of orbitofrontal involvement in food cravings, there is indirect evidence such as higher than expected co-occurrence of obsessive-compulsive behavior and eating disorders. As a result of bringing together evidence for common substrates for food and for drug rewards, we hope to be able to advance fundamental knowledge of motivational processes and to promote the development of better treatments for drug addiction and for eating disorders.     

Loss of E-cadherin and cytoplasmic-nuclear expression of beta-catenin are the most useful immunoprofiles in the diagnosis of solid-pseudopapillary neoplasm of the pancreas

Solid-pseudopapillary neoplasm of the pancreas occurs preferentially in young women and has a favorable prognosis. Differentiation of solid-pseudopapillary neoplasm from pancreatic endocrine neoplasm or adenocarcinoma can be difficult in the small biopsy specimen because they share common morphological features and immunoprofiles. Alterations of adenomatous polyposis coli (APC)/beta-catenin pathway have been identified as a genetic event contributing to the development of solid-pseudopapillary neoplasm. In the present study, to establish the diagnostic utility of beta-catenin and E-cadherin as markers for solid-pseudopapillary neoplasm, we performed immunohistochemical staining in 4 core biopsy specimens diagnosed as solid-pseudopapillary neoplasm and in tissue microarray blocks that contained histologically confirmed samples of 302 cases of adenocarcinoma, 56 cases of pancreatic endocrine neoplasm, and 50 cases of solid-pseudopapillary neoplasm. We compared the immunohistochemical results for beta-catenin and E-cadherin with those for known markers. Of the solid-pseudopapillary neoplasm cases, 51 (94.4%) were positive for nuclear beta-catenin, 45 (83.3%) were positive for CD10, 30 (55.5%) were positive for CD56, 15 (27.8%) were positive for synaptophysin, 3 (5.6%) were positive for cytokeratin (CK), and none was positive for E-cadherin and chromogranin. Of the adenocarcinoma cases, all were positive for CK, 300 (99.3%) were positive for E-cadherin, 30 (9.9%) were positive for CD10, 2 (0.7%) were positive for synaptophysin, 1 (0.3%) was positive for CD56, and none was positive for chromogranin and nuclear expression of beta-catenin. Of the pancreatic endocrine neoplasm cases, 54 (96.4%) were positive for synaptophysin and E-cadherin, 50 (89.3%) were positive for chromogranin, 26 (46.4%) were positive for CK, 15 (26.8%) were positive for CD56, 6 (10.7%) were positive for CD10, and none was positive for nuclear expression of beta-catenin. In conclusion, nuclear expression of beta-catenin and loss of E-cadherin can be used in the definite diagnosis of solid-pseudopapillary neoplasm on small biopsy specimens. CD10 immunopositivity should be carefully interpreted in the diagnosis of solid-pseudopapillary neoplasm because pancreatic adenocarcinoma or pancreatic endocrine neoplasm can also stain for CD10.     

颈椎脊神经沟内口和颈神经的观测

目的　探讨颈椎脊神经沟内口与颈神经受嵌压的关系。方法　取 2 0具成人尸体的颈椎标本 ,选用完整的成人颈椎 4 4套 ,测量颈椎脊神经沟内口的宽度和颈神经穿过脊神经沟内口时的横径 ,并统计两者之间的比值。结果　颈神经穿过脊神经沟内口处的横径为 :C3 为 2 .7± 0 .7mm ,C42 .7± 0 .7mm ,C5为 2 .8± 0 .8mm ,C64.8± 0 .9mm ,C75 .3± 1.1mm。脊神经沟内口的宽度分别为 :C3 为 5 .8± 1.0mm ,C45 .5± 0 .9mm ,C55 .6± 1.0mm ,C65 .5± 1.1mm ,C76 .2± 1.0mm ;颈神经穿过脊神经沟内口时的横径与脊神经沟内口宽度的比值 :C3 为 1∶2 .15 ,C41∶2 .0 5 ,C51∶1.98,C61∶1.14 ,C71∶1.18。结论　脊神经沟内口与穿过内口的颈神经受累关系密切 ,下颈段 (C6、C7)颈神经受累的机率大于上颈段 (C3 、C4)。     

Assessment of chronic toxicity and carcinogenicity in an accelerated cancer bioassay in rats of moxifloxacin, a quinolone antibiotic

The chronic toxicity and carcinogenicity of Moxifloxacin (MOX), a bacterial gyrase-inhibiting fluoroquinolone antibiotic, were studied in male and female Wistar rats in an accelerated cancer bioassay (ACB). The ACB is a mechanistic initiation/promotion chronic toxicity and carcinogenicity study designed to assess potential carcinogenic activity of a test substance in critical organs in which human carcinogens are active. The organs studied were liver, lungs, urinary bladder, mammary gland, bone marrow, thymus, spleen and stomach. MOX was given daily by intragastric instillation at 500 mg/kg bw/day for the first 13 weeks to produce potential initiation, followed by promoters (PROs) for 24 weeks, or for the last 24 weeks after 13 weeks of exposure to initiators (INs). The INs, administered during the first 13 weeks, were diethylnitrosamine for the liver, N-n-butyl-N-(4-hydroxybutyl)nitrosamine for the urinary bladder, ethylnitrosourea for the hematolymphoreticular system, N-nitrosodimethylamine for lungs, methylnitrosourea for the stomach and 7,12-dimethylbenz(a)-anthracene for the mammary gland. The PROs, administered during the last 24 weeks after MOX, were phenobarbital for the liver, nitrilotriacetic acid for the urinary bladder, azathioprine for the bone marrow, butylated hydroxytoluene for the lung, butylated hydroxyanisole for the forestomach, and diethylstilbestrol for the mammary gland. The INs produced preneoplastic and neoplastic lesions which were not enhanced by MOX, and MOX plus PROs elicited no neoplastic effects, documenting that MOX did not produce either initiation or promotion of neoplasia in any of the target sites, or in any of the other twenty tissues examined.