TP在子宫内膜癌中的表达及其临床意义

目的检测子宫内膜癌中胸苷磷酸化酶(TP)的表达情况,探讨它与子宫内膜癌预后的相关性及临床意义。方法采用免疫组化SP法检测15例正常内膜,10例不典型增生内膜,48例子宫内膜癌石蜡标本中的TP蛋白表达情况。结果子宫内膜癌TP表达显著高于正常内膜(PTP=0.029)。TP表达与肿瘤分化程度、浸润深度、淋巴结转移及临床病理分期无相关性(P>0.05)。结论 TP的过度表达可能与子宫内膜癌的预后有关。     

Fetal diabetes in rats and its effect on placental glycogen

Summary The role of fetal insulin in placental glycogen accumulation, which occurs despite insulin deficiency in maternal diabetes, was studied in rats. Streptozotocin was injected into fetuses of non-diabetic and streptozotocin-diabetic mothers on days 19.5 and 20.5 of gestation, causing fetal hypoinsulinaemia and pancreatic insulin depletion. Placental glycogen content of either 1.6 mg/g in non-diabetic rats or 6.5 mg/g in diabetic rats was not affected by fetal streptozotocin treatment. Glycogen distribution was also measured in the placenta to assess the effect of fetal hypoinsulinaemia on glycogen content in its fetal segment. The glycogen concentration ratio between the fetal and maternal segments in diabetic rats was 0.3 and increased to 0.5 in diabetic rats, without being affected by fetal hypoinsulinaemia. There was no significant effect of fetal hypoinsulinaemia on the activities of placental glycogen synthase or glycogen phosphorylase, both in nondiabetic and diabetic rats. Fetal hypoinsulinaemia was associated, however, with a marked decrease in fetal liver glycogen together with a decrease in fetal liver weight, which was more pronounced than the decrease in fetal body weight. Administration of insulin to the streptozotocin-treated fetuses restored the impaired glycogen synthesis (measured by incorporation of U-[¹⁴C]-glucose and ³H₂O in the fetal liver) without affecting glycogen synthesis in the placenta. These results demonstrate: (1) placental glycogen metabolism in contrast to fetal liver glycogen metabolism, is not regulated by fetal insulin; (2) the reduced fetal liver weight and its glycogen content, rather than hyperglycaemia, are the salient features of fetal insulin deficiency; and (3) placental glycogen accumulation in diabetes is related to the hyperglycaemia of maternal origin and not to the changes in maternal or fetal insulin availability.     

干扰素-α诱导肾癌细胞胸苷磷酸化酶表达对5-FU化疗敏感性的影响

目的 探讨干扰素-α诱导肾癌细胞胸苷磷酸化酶（thymidine phosphorylase，TP）表达对5-氟尿嘧啶（5-FU）化疗敏感性的影响。方法采用不同浓度的干扰素-α2b处理肾癌细胞株786—0，应用RT—PCR和免疫印迹方法分别检测TP mRNA和TP蛋白水平变化。MTT法检测不同处理组786—0细胞中5-FU的半数抑制浓度（IC50）。建立肾透明细胞癌移植瘤动物模型，观察干扰素-α2b联合5-FU化疗对移植瘤生长的影响，免疫组化检测移植瘤中TP的表达，TUNEL检测肿瘤细胞的凋亡。结果 干扰素-α2b3000和6000IU／ml处理组，TP mRNA表达量（灰度峰值）分别为0．5733±0．0231和0．8233±0．0404，TP蛋白表达量分别为0．6347±0．0719和0．8735±0．0640。干扰素-α对TP的表达有剂量依赖性增强作用（P〈0．01）。在干扰素-α2b作用下，5-FU对786—0半数抑制浓度由（13．9467±3．7140）μmol／L下降至（5．3200±0．1039）μmol／L，化疗敏感性增加（P〈0．01）。联合用药组移植瘤体积为（0．0940±0．0492）cm^3，小于单纯5-FU组的（0．5424±0．1591）cm^3（P〈0．05）。单纯5-FU组和联合用药组移植瘤中肿瘤细胞凋亡指数差异无统计学意义（P〉0．05）。结论 干扰素-α2b诱导的TP增强表达参与了干扰素-α联合5-FU化疗增效作用，TP是干扰素-α2b的靶基因之。     

红细胞嘌呤核苷磷酸化酶与网织红细胞的辐射效应

通过比较不同条件下大鼠红细胞螵呤核苷磷酸化酶(PNP)活力和网织红细胞数的变化,探讨红细胞PNP在辐射损伤中的意义.实验用正常大鼠血经离心、去除血浆及白细胞层后:上层和底层血网织红细胞和PNP活力分别为(2.5±0.47)%,45.3±10.5单位;(0.88±0.29)%,18.6±6.5单位.两者呈高度正相关.皮下注射笨肼后,网织红细胞显著增多,红细跑PNP活力亦相应升高,呈高度正相关.大鼠经2、4、6Gyγ射线照射后,红细胞PNP活力降至照前的31.9%～24.8%,网织红细胞数降至0.76%～0.02%,两者最低值均与剂量生高度负相关.恢复时问与剂量呈线性关系.受熙后红细胞PNP活力与网络红细胞计数的变化量正相关.     

6‐[(2‐Iminopyrrolidinyl)methyl]‐5‐[125I]iodouracil as a potential thymidine phosphorylase‐targeted radiopharmaceutical: synthesis and preliminary biological evaluation

Thymidine phosphorylase (TP) is expressed at higher levels in many types of malignant tumors than in adjacent nonneoplastic tissues. The aim of this study was to develop a radiolabeled TP inhibitor, 6‐[(2‐iminopyrrolidinyl)methyl]‐5‐[¹²⁵I]iodouracil ([¹²⁵I]1) as a TP‐targeted radiopharmaceutical. No‐carrier‐added [¹²⁵I]1 was synthesized by halogen exchange of the corresponding bromide (2). After purification by reverse‐phase HPLC, [¹²⁵I]1 showed a radiochemical purity of over 97%. When administered to normal mice, [¹²⁵I]1 showed a rapid clearance from the blood and a low accumulation in the thyroid and stomach, indicating good in vivo stability against deiodination. By coinjection of unlabeled 1, the uptakes in the TP‐expressing normal tissues, small intestine and liver were significantly reduced, suggesting TP‐specific modes of accumulation of [¹²⁵I]1. These findings suggest that [¹²⁵I]1 possesses the required properties for in vivo imaging of TP activity. Copyright © 2009 John Wiley & Sons, Ltd.     

Organization of the mouse cerebral cortex: A histochemical study using glycogen phosphorylase

The postmortem phosphorylase a activity in cryostal sections taken from the brains of mice killed without any prior period of maintained anaesthesia (‘unanesthetized’ mice) was compared histochemically with the activity in sections taken from mice anaesthetized with pentobarbitone prior to decapitation (‘anaesthetized’ mice). This study provides evidence for the existence of two separate overlapping modular subdivisions of the somatosensory cortex. The modules observed in the ‘unanaesthetized’ mice were restricted to layer IV and corresponded to the hollows of the whisker barrels where the thalamic afferents terminate. In contrast, the modules observed in the ‘anaesthetized’ mice extended from layer I to layer V, and formed a mosaic of cylinders that was out of register with the whisker barrels. These cylinders may correspond to the terminal fields of corticocortical afferents.In a few of the ‘unanaesthetized’ mice bands of high phosphorylase a activity are evident in the visual areas 17 and 18. This suggests that in the mouse, as in higher mammals, the thalamic input to the visual cortex gives rise to a columnar organization. In the ‘anaesthetized’ mice the mosaic of modules observed in the somatosesory cortex is also present in the auditory and motor areas. The modules in both groups of mice have similar diameters of between 200 and 350 μm.     

大肠杆菌多核苷酸磷酸化酶的快速高效纯化

利用快速蛋白质液相层析仪从大肠杆菌纯化到2500倍的多核苷酸磷酸化酶,回收率45.5％,SDS-聚丙烯酰胺凝胶电泳结果显示为单一组分,经测定未检出RNA酶、磷酸单酯酶和5’-核苷酸酶活性。     

Synergistic inhibition of human leukemia cell growth by deoxyguanosine and 1-beta-D-arabinofuranosylcytosine

We studied the ability of 2'-deoxyguanosine (dGuo) to influence 1-beta-D-arabinofuranosylcytosine (ara-C) inhibition of soft agar cloning of the cultured human leukemia cell line K562. Ara-C alone inhibited cloning in concentrations of greater than 10 nM, with a steep drop in colony formation observed between 10 and 100 nM. dGuo and ara-C synergistically inhibited cloning; the combination of ineffective concentrations of dGuo (10-50 microM) and ara-C (less than or equal to nM) inhibited cloning by 40-70%. In K562 cells, dGuo is metabolized by both nucleoside kinase and purine nucleoside phosphorylase (PNP), resulting in augmentation of both the GTP pool (to more than 200% of control after a 3 hr incubation with 500 microM dGuo) and the dGTP pool (to more than 2700% of control after 3 hr with 500 microM dGuo). dGuo (50-500 microM) caused a decrease in the dCTP and dTTP pools and an increase in the dATP pool. Synergistic concentrations of dGuo plus 10 nM ara-C augmented the ara-CTP pool up to 800% of control after 3 hr to levels equivalent to those observed after incubation with 500 nM ara-C alone. Incorporation of 10 nM ara-CTP into DNA also increased in the presence of dGuo (up to a maximum of 300% of control), but only to a level that approximated the value observed with nM ara-C alone. The disparity between enlargement of the ara-CTP pool and augmentation of ara-C incorporation into DNA is consistent with the observation of Steinberg et al. [Cancer Res. 39, 4330 (1979)] that high concentrations of dGTP may inhibit DNA polymerase activity. Thus, synergy between dGuo and ara-C is multifactorial, possibly involving inhibition of DNA polymerase by elevated dGTP and ara-CTP pools and augmented incorporation of ara-C into DNA.