Development of Activity Assays for High-Volume Evaluation of Human Immunodeficiency Virus (HIV) Protease Inhibitors in Rat Serum: Results with Ditekiren

We showed previously that a commercially available synthetic tetradecapeptide, Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Leu-Val-Tyr-Ser, produces authentic angiotensin I (Ang I) upon incubation with the HIV-1 protease (S. K. Sharma et al., Anal. Biochem. 198:363, 1991). Therefore, we developed an Ang-I based activity assay for HIV protease inhibitors based on the technology developed earlier (M. J. Ruwart et al., Pharm. Res. 7:407, 1990; S. K. Sharma et al., Anal. Biochem. 186:24, 1990) for tracking renin inhibitors in rat sera. Ditekiren was either extracted from sera with ethyl acetate or assayed after the interfering substances in sera were precipitated with acetonitrile. Purified recombinant HIV-1 protease was added to extracted rat serum and the enzymatic reaction was initiated in the presence of the tetradecapeptide substrate. The inhibition of Ang I production was measured by a commercially available RIA kit. The cleanup methodology also enabled a commercially available Proteinase Scintillation Proximity Assay (SPA, Amersham) to quantify ditekiren in rat serum through the addition of recombinant HIV-1 protease and cleavage of substrate from SPA beads. Results were confirmed by HPLC or by the renin assay for ditekiren, which inhibits both aspartyl proteases. These technologies should prove useful for assessing serum levels of HIV protease inhibitors in rat.     

NGF prevents the changes induced by monocular deprivation during the critical period in rats

Photic evoked responses were recorded from the striate cortex of Long-Evans hooded intact, monocular visual deprivation (MD) and MD treated with NGF rats. The averaged visual evoked responses (AVER) were obtained from both hemispheres and provided comparison after binocular photic stimuli between the contralateral and the ipsilateral striate cortex with relation to the MD eye. One month of monocular visual deprivation at the critical period of development resulted in marked reduction of the amplitudes of AVER components as compared to the control recordings (P < 0.001). These changes of the AVER could be prevented by NGF infusion to lateral ventricle at the dosage of 2.0–2.4 μg/day for four weeks during the monocular deprivation. In conclusion, the change of AVER amplitudes induced by monocular visual deprivation during the critical period of development can be prevented by NGF infusion to lateral ventricle.     

The possible role of stromal cell stimulation in worsening the prognosis of a subset of patients with breast cancer

This review examines the evidence that a subset of patients with breast cancer have tumors that are stimulated to grow by host cells in the tumor stroma. The search for such a minority group was prompted by the following observations. Adjuvant chemotherapy which is immunosuppressive improves disease-free interval and survival, whereas non-specific immunostimulation worsens the prognosis. Intrinsic immune reactivity is associated with a poor prognosis. A subset of tumors with a bad prognosis has anaplastic cells, dermal lymphatic invasion and a moderate to intense lymphoplasmacytic stromal infiltrate. Evidence is reviewed that adjuvant chemotherapy may be beneficial by virtue of its immunosuppressive effects in addition to tumor kill of minimal residual disease.     

Granulocyte-macrophage colony stimulating factor inhibits class II major histocompatibility complex expression and antigen presentation by microglia

Granulocyte-macrophage colony stimulating factor (GM-CSF) modulates various functions of monocytes/ macrophages including antigen-presenting capacity. Recently it was found that astrocytes produce GM-CSF in the central nervous system (CNS) and that GM-CSF can induce proliferation and morphological changes of microglia. Here we show that GM-CSF can down regulate the interferon-γ-mediated induction of major histocompatibility complex (MHC) class II antigens in microglia, but not in astrocytes. GM-CSF pretreatment completely prevents myelin basic protein-specific T cell proliferation induced by microglia but not astrocytes. GM-CSF did not affect the cell surface expression on microglia of either MHC class I or cell adhesion molecules. The inhibition of microglial MHC class II expression and antigen-presenting function is specific for GM-CSF, as treatment with a different CSF (interleukin-3) did not modulate microglial phenotype or functional capacity. These data suggest that GM-CSF might be involved in the regulation of immune responses within the central nervous system.     

高浓度氨基酸对肿瘤细胞体外增殖的影响

本研究首先采用Hanks溶液作为介质,观察了不同氨基酸浓度(1～5mmol/L)对艾氏腹水癌细胞、瓦克癌肉瘤256细胞体外增殖的影响,然后以含有平衡氨基酸组成的Eagle最低必需培养基作为介质进一步观察了不同氨基酸浓度的增加对艾氏腹水癌细胞及人肝癌细胞(PLC/PRF/5)、肺癌细胞(AGTJ-a)体外增殖的影响,同时采用小鼠骨髓细胞观察了高浓度氨基酸对正常组织细胞可能产生的毒性作用。结果表明,尽管一些氨基酸浓度的增加有显著作用,但是不同肿瘤细胞对不同氨基酸浓度增加的反应不尽一致,而且一些氨基酸的作用受培养介质的明显影响;高浓度色氨酸对小鼠骨髓细胞的体外增殖有显著抑制作用。     

内皮超极化因子的研究进展

内皮超极化因子（EDHF）是由内皮释放的NO和PGI_2以外的另一种舒张因子,它通过使平滑肌细胞膜超极化而舒张血管,是内皮依赖性血管松驰的第3种重要机制。EDHF可能是花生四烯酸的细胞色素P450代谢产物EET-s,乙酰胆碱、缓激肽等激动剂作用于内皮细胞,使细胞内游离钙浓度升高,合成和（或）释放EDHF,作用于平滑肌细胞膜,激活钙依赖性钾通道,使细胞膜超极化,抑制电压依赖性钙通道的开放,引起血管松弛。在大血管中NO-cGMP松弛机制可能占主导地位,并且抑制EDHF生成;而在阻力小血管,EDHF则可能是引起血管松弛的主要因素。     

人乳头瘤病毒感染的局部免疫反应

本文应用ABC法对30例尖锐湿疣(CA)和30例宫颈癌(CCU)进行原位观察,分析对比两者浸润单一核细胞(MNC)的亚群组成、分布及活化状态。结果提示,两者局部免疫均受抑制,而以宫颈癌为甚。依此本文对不同类型HPV相关疾病的局部免疫反应状态及宿主对不同型别HPV感染的免疫反应进行探讨。     

rhGM-CSF基因真核表达载体的构建及其在COS-7细胞和小鼠体内的表达

将ｈＧＭＣＳＦ基因克隆至真核表达质粒ｐＣＤＳ中，构建成重组质粒ｐＣＧ１。用电穿孔法将质粒ｐＣＧ１导入ＣＯＳ７细胞和直接注射小鼠骨骼肌内，ＥＬＩＳＡ检测显示质粒ｐＣＧ１转染ＣＯＳ７细胞后４８、７２、９６ｈ和肌注质粒ｐＣＧ１后ｄ１０、ｄ１５、ｄ２０、ｄ２５小鼠体内均有ｈＧＭＣＳＦ的表达。生物学活性检测显示含肌注ｐＣＧ１的小鼠血液有维持ＴＦ１细胞生长的作用，表明重组质粒ｐＣＧ１表达分泌的ｈＧＭＣＳＦ具有生物学活性     

浅低温对犬全脑缺血再灌注后脑组织形态及脑功能的影响

研究浅低温对犬心脏停跳复苏后脑组织形态学及脑功能的影响。缺血时间１８ｍｉｎ，再灌注８ｈ，观察神经机能及脑顶叶皮质形态学改变，并对顶叶皮层神经细胞及毛细血管进行体视学分析。结果表明，浅低温综合治疗可明显减轻神经细胞及毛细血管的损害，促进脑功能的恢复。