Spontaneous Reversal of P‐Glycoprotein Expression in Multidrug Resistant Cell Lines*

Abstract: Increased expression of P‐glycoprotein encoded by the mdr‐1 gene is a well‐characterised mechanism for resistance to cancer chemotherapeutic drugs in cell lines. However, the P‐glycoprotein expression after removal of the selection pressure has not fully been elucidated. The stability of P‐glycoprotein expression in the presence (+) and absence (?) of vincristine (30 or 150 nM) was studied in multidrug resistant K562 cell lines (VCR30+, VCR150+, VCR30? and VCR150?) for 11 months. The P‐glycoprotein protein and mdr‐1 mRNA levels were determined at regular intervals using flow cytometry and real‐time PCR, respectively. Chemosensitivity to a panel of antineoplastic drugs was measured using an MTT assay. The presence of vincristine (VCR30+ and VCR150+) resulted in high and stable levels of P‐glycoprotein and mdr‐1 mRNA during the whole period compared to wild type. As for the VCR30? and VCR150? subcultures, the expressions of P‐glycoprotein and mdr‐1 mRNA were stable for five months, and then the levels decreased rapidly. Concomitantly, the sensitivity to drugs known as P‐glycoprotein substrates was restored. In conclusion, resistant cells growing in the presence of the inducing drug have a stable P‐glycoprotein expression and resistance level, but removing the inducing drug may result in a sudden and rapid lowering of P‐glycoprotein and mdr‐1 mRNA levels as long as five months after drug withdrawal.     

葛根素对糖尿病大鼠肾功能及肾组织MMP-2与TIMP-2表达的影响

目的探讨葛根素对糖尿病大鼠肾功能及肾组织基质金属蛋白酶2（MMP-2）及其组织抑制剂2（TIMP-2）表达的影响。方法单侧肾切除大鼠ip链脲佐菌素诱发糖尿病模型。用原位杂交法检测肾小球MMP-2及TIMP-2 mRNA表达，流式细胞术和免疫组织化学检测肾皮质TGFβ1，MMP-2，TIMP-2,IV型胶原及层粘连蛋白表达。结果 糖尿病组较对照组肾小球MMP-2 mRNA及蛋白表达降低而TIMP-2 mRNA及蛋白表达升高，TGFβ1，IV型胶原及层粘连蛋白表达亦增加，肾功能恶化；葛根素用药组较糖尿病组肾小球MMP-2 mRNA及蛋白表达升高，而TGFβ1，TIMP-2，IV型胶原及层粘连蛋白表达减少，肾功能改善。结论葛根素对糖尿病大鼠肾功能具有保护作用，除降低血糖外，调节肾小球MMP-2及TIMP-2表达，从而减轻肾小球细胞外基质沉积也可能是其作用途径之一。     

先天性心脏病患者心功能与肺功能相互关系的临床研究

目的 探讨先天性心脏病患者心功能与肺功能的相互关系。方法 随机选择60例先天性心脏病患者于术前、术后近期、术后远期,拍心脏前后位远达片,进行肺功能检查及运动前后血气检测。对不同时期的心功能级别、心胸比例与肺功能参数,经统计学处理进行比较。结果 资料显示随心功能的降低,心胸比例增大,肺损害加重;术后近期肺功能改善不明显,术后远期随心功能的改善,心胸比的缩小,肺功能明显改善;但小气道阻塞及肺弥散功能、功能残气比改善较慢。结论心功能直接影响肺功能,两者呈正相关关系。     

Synthesis and physico‐chemical properties of peptides in soil humic substances

Abstract: Soil humic substances (HS) are heterologous, polydispersive, and multi‐functional organometallic macromolecules ubiquitous in soils and sediments. They are key players in the maintenance of the belowground ecosystems and in the bioavailability of both organic and inorganic contaminants. It is widely assumed that the peptidic substructures of HS are readily degraded and therefore do not contribute significantly to interactions with contaminants such as toxic metals. To investigate the turnover of humified peptides, laboratory soil aging experiments were conducted with ¹³C‐glucose or ¹⁵N‐nitrate for 8.5 months. Evidence for random‐coil peptidic structures in the labeled HS was obtained from 2‐D nuclear magnetic resonance (NMR), pyrolysis gas chromatography‐mass spectrometry (pyro‐GC‐MS), and circular dichroism data. Interaction of metals with the peptidic carbonyls of labeled HS was rationalized from the solid‐state NMR data. Detailed ¹³C and ¹⁵N labeling patterns of amino acid residues in the acid hydrolysates of HS acquired from NMR and GC‐MS revealed two pools of peptides, i.e. one extant (unlabeled) and the other, newly humified with little isotopic scrambling (fully labeled). The persistence of pre‐existing peptidic structures indicates their resistance to degradation while the presence of fully labeled peptidic amino acids suggests wholesale incorporation of newly synthesized peptides into HS. These findings are contrary to the general notion that humified peptides are readily degraded.     

Pharmacodynamic differences between species exemplified by the novel anticancer agent CHS 828

When a candidate drug enters clinical trials, decisions regarding dosing are mainly based on animal data. Occasionally, toxicity problems are faced in the clinic because of unexpected species differences in pharmacokinetics or pharmacodynamics between humans and preclinical species. Fludarabine and topotecan are examples of such drugs. In the first clinical trials of the new agent CHS 828, the maximum tolerated dose was reached earlier than expected from animal data. This paper discusses the issue of species differences in the development of anticancer drugs, and preclinical models for detection and quantification of such differences. Pharmacokinetic and hematological toxicity data of CHS 828 from studies in rats and humans are presented. In vitro sensitivity to CHS 828 and some established cytotoxic agents was measured in lymphocytes from humans and rats and in a panel of human and rodent cell‐lines. 10–100 times higher CHS 828 exposure was tolerated by rats than by patients. In both in vitro cell systems, CHS 828 showed higher potency in human cells compared to rodent cells. A species difference was evident also for fludarabine, but not for doxorubicin and cisplatin. CHS 828 pharmacokinetics were similar across species. In conclusion, the lower tolerance of CHS 828 in humans than in rats could be detected in vitro in cultures of peripheral lymphocytes. Preclinical studies of species differences could help the interpretation of in vivo effect studies as well as the choice of starting dose for clinical trials. We suggest peripheral lymphocytes from different species as a potential model system for such studies. Drug Dev. Res. 61:218–226, 2004. © 2004 Wiley‐Liss, Inc.     

Inhibition of β‐amyloid toxicity by short peptides containing N‐methyl amino acids

Abstract: Single N‐methyl amino acid‐containing peptides related to the central hydrophobic region β_16–20 (Lys‐Leu‐Val‐Phe‐Phe) of the β‐amyloid protein are able to reduce the cytotoxicity of natural β_1–42 in PC12 cell cultures. N‐methyl phenylalanine analogs yield statistically significant increments in cell viability (Student's t‐test < 0.01%) and are nontoxic in the same assay. These promising results indicate that these peptide molecules could be a starting point for the development of potential therapeutic compounds for the treatment of Alzheimer's disease.     

几种中药的化学振荡指纹图谱

应用振荡技术，采用KBrO3-MnSO4-H2SO4-丙酮振荡器，得到了解表药柴胡、葛根、连翘，祛风湿药木瓜、独活、五加皮和理血药鸡血藤、丹参、虎杖的振荡指纹图谱。结果表明，这些化学振荡指纹图谱可用于辨识中药。     

晚期食管癌联合放化疗与单纯放疗疗效比较及复发情况分析

目的　观察晚期食管癌联合放化疗后的治疗效果及复发和转移时间。方法　 4 0例晚期食管癌患者分为两组 ,联合放化疗组 (综合组 )和单纯放疗组 (单放组 )。用60 CO治疗机照射 2Gy/次 ,总量 5 0～ 6 0Gy/ 5～ 6周 ,综合组在放疗d1、5、8周分别给予DDP、VCR、F -FU化疗 ,并随访 1年。结果　综合组和单放组疗效相仿 ,无显著统计学差异 (P <0 0 5 ) ,随访 6个月～ 12个月 ,单放组患者共 14例发生远处转移 ,2例局部复发 ,综合组仅 1例转移 (P <0 0 1) ,有显著统计学意义 ,毒副反应综合组略高于单放组。结论　联合放化疗是控制晚期食管癌复发和转移的主要治疗方案。     

乳腺肿瘤基质金属蛋白酶2表达与肥大细胞的关系

[目的]探讨乳腺肿瘤中基质金属蛋白酶2(matrix meta]]oproteinase2,MMP-2)表达及其与肥大细胞浸润的关系.[方法]采用甲苯胺蓝染色显示55例良恶性乳腺肿瘤组织的肥大细胞,免疫组化EnVision法检测肿瘤细胞MMP-2以及类胰蛋白酶(tryptase)的表达.[结果]乳腺癌间质成纤维细胞MMP-2的反应程度明显高于癌细胞.浸润性小叶癌和浸润性导管癌MMP-2的阳性率达86.7%,明显高于恶性程度较低的黏液腺癌和髓样癌(20.0%)以及乳腺的良性肿瘤(13.3%).局部有转移的乳腺癌组织中MMP-2的表达程度明显高于无转移组.乳腺肿瘤间质中肥大细胞的数量以及tryptase的表达量与MMP-2相似,但是与MMP-2的表达量并无明显的相关性.[结论]MMP-2的表达是乳腺癌一个预后指标,而肥大细胞的增多可能是肿瘤纤维间质形成的相伴现象.     

Ten-year outcomes in a population-based cohort of node-negative, lymphatic, and vascular invasion-negative early breast cancers without adjuvant systemic therapies.

PURPOSE: To discuss the absolute benefits from adjuvant systemic therapy knowledge of long-term outcomes and baseline risks of relapse and disease-specific survival are required. We assessed the 10-year outcomes in a population-based cohort of node-negative (N-) lymphovascular negative (LV-) early breast cancers diagnosed from 1989 to 1991 who did not receive adjuvant systemic therapy. METHODS: One thousand one hundred eighty-seven cases of pT(1-2)N(0) LV- breast cancers with a median follow-up of 10.4 years were reviewed. Kaplan-Meier survival curves for relapse free survival (RFS), breast cancer-specific survival (BCSS) and overall survival (OS) were compared with log-rank tests with cohorts stratified for tumor size and grade. RESULTS: The median age of this series was 62 years. Four hundred thirty tumors were < or = 1 cm in diameter (cohort 1), 507 were 1.1-2 cm (cohort 2), and 250 were 2.1 to 5 cm in diameter (cohort 3). The 10-year outcomes for cohorts 1, 2, and 3, respectively, were significantly different: RFS, 82%, 75%, and 66%; BCSS, 92%, 90%, and 77%; and OS, 79%, 78%, and 66%. Tumor grade significantly altered outcome within size cohorts, particularly in pT(1)N(0) breast cancers. CONCLUSION: This study provides detailed information on the continued relapse and breast cancer death rate to 10 years of follow-up. Specifically, without adjuvant systemic therapy, patients with LV-, N - breast cancer had a > or = 25% 10-year risk of relapse and a corresponding 10-year breast cancer death rate of > or = 10% if they had either a grade 3 tumor < or = 1 cm, a grade 2 to 3 tumor from 1.1 to 2 cm, or any grade tumor greater than 2 cm.