联合应用神经保护剂对大鼠局灶性脑缺血后bcl-2表达的影响

目的：探讨不同类型神经保护剂联合应用是否较单一神经保护剂对局灶性脑缺血有更好的保护作用。方法：采用线栓法制作大鼠大脑中动脉闭塞模型（MCAO）,并分为1,6－二磷酸果糖（FDP）组、MK－801组、N－乙酰半胱氨酸（NAC）组,联合治疗组和对照组,应用western印记技术观察缺血后6和24h抗凋亡蛋白bcl-2表达的变化,结果：缺血后6h和24h,联合治疗组bcl-2表达明显增加,与单一用药各组相比有显性差异。结论：神经保护剂联合应用对大鼠脑组织缺血的保护作用较单一用药各组明显增强。     

Effect of O6-(4-bromothenyl)guanine on different temozolomide schedules in a human melanoma xenograft model

The DNA repair protein O(6)-alkylguanine DNA alkyltransferase (ATase) is a major component of resistance to treatment with methylating agents and nitrosoureas. Inactivation of the protein, via the administration of pseudosubstrates, prior to chemotherapy has been shown to improve the latter's therapeutic index in animal models of human tumours. We have also shown that rational scheduling of temozolomide, so that drug is administered at the ATase nadir after the preceding dose, increases tumour growth delay in these models. We now report the results of combining these two approaches. Nude mice bearing A375M human melanoma xenografts were treated with vehicle or 100 mg/kg temozolomide ip for 5 doses spaced 4, 12 or 24 hr apart. Each dose was preceded by the injection of vehicle or 20 mg/kg 4BTG. All treatments resulted in significant delays in tumour quintupling time compared with controls: by 6.2, 5.9 and 16.8 days, respectively, for 24-, 12- and 4-hourly temozolomide alone and by 22.3, 21.3 and 22.1 days, respectively, in combination with 4BTG. Weight loss due to TMZ was unaffected by the presence of 4BTG. This was of the order of 6.2-10.6% with 24- and 12-hourly administration and 17.4-20.1% (p < 0.0001) with 4-hourly treatment. In our model, combining daily temozolomide with 4-BTG confers increased antitumour activity equivalent to that achieved by compressing the temozolomide schedule but with less toxicity. Using temozolomide schedule compression with 4-BTG does not improve on this result, suggesting that ATase inactivation with pseudosubstrates is a more promising means of enhancing the activity of temozolomide than compressed scheduling.     

Chemoprevention of prostate cancer: current status and future directions

Prostate cancer chemoprevention can be described as the administration of natural products and pharmaceutical agents that inhibit one or more steps in the natural history of prostatic carcinogenesis. The principle components of the chemoprevention strategy are closely connected to this natural history and include: (a) agents and their molecular targets; (b) strategic intermediate endpoint biomarkers (IEBs) and their critical pathways; (c) cohorts identified by genetic and acquired risk factors and (d) efficient designs that combine these elements into a cohesive clinical trial. The primary goal is to find effective noncytotoxic agents that modulate the promotion and progression from normal epithelium to dysplasia to high-grade prostatic intraepithelial neoplasia (HGPIN) to locally invasive cancer and metastatic disease. Another important target for chemoprevention is to modulate progression to clinically aggressive disease and to maintain an androgen-sensitive clinical state and delay the emergence of androgen resistance. There is a rationale for use of antiandrogens as the lead class, e.g., 5 alpha receptor inhibitors (5ARI), for chemoprevention of prostate cancer. Nevertheless, the desire to improve the therapeutic index, achieve synergy (5ARI may have only modest anticancer effects) and prevent the emergence of drug (androgen) resistance provide incentives for developing other effective agents and combinations. The availability of more than a dozen classes of noncytotoxic pharmaceutical and natural products already in clinical development create many opportunities for rational combination therapy. Several agent classes have a pharmacodynamic basis for combination with antiandrogens including antiproliferatives, selective estrogen receptor modulators (SERMs), proapoptotic antioxidant micronutrients and selective cyclo-oxygenase (COX)-2 inhibitors. Many other rational pharmacodynamic combinations without antiandrogens are feasible. It is anticipated that in the future, a selective COX-2 inhibitor may be combined with other agent classes such as proapoptotic antioxidant micronutrients, receptor tyrosine kinase modulators, antiangiogenic modulators, antiproliferative/differentiating agents, NFrkappaB modulators, IGF-1 modulators and other novel proapototic nonsteroidal drugs. A novel target for rational combinations is the hypermethylation of GST-PI leading to functional silencing of this key anticarcinogen defense enzyme in precursors (HGPIN) and prostate cancer. Factorial designs are well suited for evaluating the individual and combined effects of each agent in a single trial design. There are a number of moderate to high-risk cohorts and clinical models of primary and secondary prevention that can be employed in both short-term developmental (translational) trials for proof of biologic activity and in intermediate sized longer-term chemoprevention trials for proof of efficacy against prostate cancer. Strategic IEBs are needed to more efficiently monitor short-term biologic activity and validate efficacy. The emergence of new powerful tools such as gene chip cDNA microarrays for multiplex gene expression profiling and proteomic analysis of tissue based and secreted proteins will accelerate the identification of new molecular targets, strategic endpoints, cohorts at risk and the design of rational combination trials.     

Expression of MDR1/P-glycoprotein,the multidrug resistance protein MRP,and the lung-resistance protein LRP in multiple myeloma

The purpose of this study was to determine the incidence of three genes associated with multidrug resistance (MDR) in multiple myeloma in relation to treatment status. MDR1/Pgp (P-glycoprotein) expression was detected in 41% of 93 myeloma samples. Generally, the incidence of MDR1/Pgp expression was higher in pretreated samples, and treatments with doxorubicin and/or vincristine were more effective in MDR1/Pgp expression than with alkylating agents. A significant association was observed between MDR1/Pgp-positiveness and the ability of verapmil to increase doxorubicin sensitivity, suggesting functional relevance of MDR1/Pgp expression. MRP (multidrug resistance protein) expression was detected in 20.5% of 88 myeloma samples, in 26% at the mRNA level analyzed by quantitative reverse transriptase-polymerase chain reaction, and in only 3 of 79 samples by immunohistochemistry. LRP (lung-resistance protein) protein expression was observed in 12.5% of 72 myeloma samples. MRP and LRP expression was similar in samples with and without prior therapy. Approximately 80% of the myeloma samples with detectable mRNA expression of MDR1 and MRP exhibited low expression levels corresponding to <10% of the Pgp- and MRP-overexpressing multidrug-resistant human myeloma cell lines 8226/Dox6 and 8226/DOXint40c, respectively. Some normal bone marrow samples showed higher levels of MRP mRNA as compared to myeloma specimens, whereas MDR1 mRNA expression in normal bone marrow was much lower (≤ 5%) than that in 8226/Dox6. These findings indicate a requirement to develop single-cell assays for MRP detection in multiple myeloma that are more sensitive than immunohistochemistry and might be useful to evaluate the incidence of genes associated with MDR.     

Iron-oxide-enhanced MR imaging of bone marrow in patients with non-Hodgkin's lymphoma: differentiation between tumor infiltration and hypercellular bone marrow

The aim of this study was to differentiate normal, hypercellular, and neoplastic bone marrow based on its MR enhancement after intravenous administration of superparamagnetic iron oxides in patients with cancer of the hematopoietic system. Eighteen patients with cancer of the hematopoietic system underwent MRI of the spine before and after infusion of ferumoxides ( n=9) and ferumoxtran ( n=9) using T1- and T2-weighted turbo spin-echo (TSE) and short tau inversion recovery sequences (STIR). In all patients diffuse or multifocal bone marrow infiltration was suspected, based on iliac crest biopsy and imaging such as conventional radiographs, MRI, and positron emission tomography. In addition, all patients had a therapy-induced normocellular ( n=7) or hypercellular ( n=11) reconversion of the normal non-neoplastic bone marrow. The MRI data were analyzed by measuring pre- and post-contrast signal intensities (SI) of hematopoietic and neoplastic marrow and by calculating the enhancement as deltaSI(%) data and the tumor-to-bone-marrow contrast as contrast-to-noise ratios (CNR). Changes in bone marrow signal intensity after iron oxide administration were more pronounced on STIR images as compared with T1- and T2-weighted TSE images. The STIR images showed a strong signal decline of normal and hypercellular marrow 45-60 min after iron oxide infusion, but no or only a minor signal decline of neoplastic bone marrow lesions; thus, deltaSI% data were significantly higher in normal and hypercellular reconverted marrow compared with neoplastic bone marrow lesions ( p<0.05). Additionally, the contrast between focal or multifocal neoplastic bone marrow infiltration and normal bone marrow, quantified by CNR data, increased significantly on post-contrast STIR images compared with precontrast images ( p<0.05). Superparamagnetic iron oxides are taken up by normal and hypercellular reconverted bone marrow, but not by neoplastic bone marrow lesions, thereby providing significantly different enhancement patterns on T2-weighted MR images; thus, superparamagnetic iron oxides are useful to differentiate normal and neoplastic bone marrow and to increase the bone marrow-to-tumor contrast.     

The OptiMARK clinical development program: summary of safety data

PURPOSE: To describe and summarize the safety data from the OptiMARK clinical development program. MATERIALS AND METHODS: In the 18 clinical studies comprising the clinical program, doses ranging from 0.1 to 0.7 mmol/kg were administered to healthy adult volunteers, patients with hepatic or renal impairment, and patients with confirmed or highly suspected central nervous system (CNS), liver, breast, vascular, bone, or soft tissue pathologies. A total of 2038 injections of OptiMARK, Magnevist, or placebo were administered to 1684 subjects. Safety assessments were performed at appropriate intervals during all Phase 1, 2, and 3 studies. RESULTS: Of the 1684 subjects exposed to a study drug or placebo in the clinical development program, 646 subjects experienced 1293 adverse events. Thirty-one percent of the OptiMARK injections were associated with an adverse event. In comparison, 35% of Magnevist injections and 48% of placebo injections were associated with at least one adverse event. CONCLUSIONS: OptiMARK was safe and well-tolerated with a safety profile similar to that of Magnevist.     

抗高血压药物对血压正常的冠心病患者心血管事件影响评价

4 背景 血管紧张素转换酶抑制剂和钙拮抗剂对血压相对正常或有临界性高血压的冠心病患者有益，但抗高血压药物对血压正常的冠心病患者心血管事件的影响尚未明确。     

热毒宁注射液治疗急性上呼吸道感染的临床研究

目的:评价热毒宁注射液治疗急性上呼吸道感染外感风热证的疗效和安全性。方法:71例急性上呼吸道感染病人随机分为2组,试验组给予热毒宁注射液治疗,20 ml.次.d-1,静脉滴注;对照组给予清开灵注射液治疗,1次.d-1,每次30 ml,静脉滴注。3 d为一个疗程。结果:治疗d 3试验组总体疗效优于对照组(98.08%,94.13%,P<0.01)。治疗d 3试验组中医证候疗效优于对照组(98.07%,94.11%,P<0.05)。未见明显的毒副作用和不良反应症状。结论:用药3 d后热毒宁注射液治疗急性上呼吸道感染外感风热证的疗效优于清开灵注射液,并且安全性良好。     

革兰阴性杆菌感染现状及应对措施

细菌感染已经成为临床不可忽视的问题。在感染菌谱中,革兰阴性杆菌感染具有明显加剧趋势,且耐药现象日趋严重,严重影响了药物的疗效和疾病的预后。本文就革兰阴性杆菌感染现状、耐药状况、耐药机制以及应对措施进行综述,为临床合理选择抗生素提供依据。