PLS—紫外分光光度法同时测定复方阿斯匹林片中三组分含量

本文研究了复方阿斯匹林片中阿斯匹林、非那西丁和咖啡因含量同时测定的紫外分光光度法的最佳实验条件,并简述偏最小二乘法(PLS)在多组分同时测定中的基本原理和应用。三组分模拟试样回收率平均值的置信区间分别为100.1±0.23%,100.0±0.25%和100.1±0.33%(置信度95%)。PLS法是一种理想的多组分测定方法,计算速度较快,结果更准确可靠,尤其适用于成批试样的分析,为微机控制的紫外可见分光光度计提供了一种新方法。     

Gene therapy for diabetic peripheral neuropathy: A randomized,placebo‐controlled phase III study of VM202, a plasmid DNA encoding human hepatocyte growth factor

AbstractVM202 is a plasmid DNA encoding two isoforms of hepatocyte growth factor (HGF). A previous phase II study in subjects with painful diabetic peripheral neuropathy (DPN) showed significant reductions in pain. A phase III study was conducted to evaluate the safety and efficacy of VM202 in DPN. The trial was conducted in two parts, one for 9 months (DPN 3‐1) with 500 subjects (VM202: 336 subjects; and placebo: 164) and a preplanned subset of 101 subjects (VM202: 65 subjects; and placebo: 36) with a noninterventional extension to 12 months (DPN 3‐1b). VM202 or placebo was administered to calf muscles on days 0 and 14, and on days 90 and 104. The primary end point in DPN 3‐1 was change from baseline in the mean 24‐h Numerical Rating Scale (NRS) pain score. In DPN 3‐1b, the primary end point was safety, whereas the secondary efficacy end point was change in the mean pain score. VM202 was well‐tolerated in both studies without significant adverse events. VM202 failed to meet its efficacy end points in DPN 3‐1. In DPN 3‐1b, however, VM202 showed significant and clinically meaningful pain reduction versus placebo. Pain reduction in DPN 3‐1b was even greater in subjects not receiving gabapentin or pregabalin, confirming an observation noted in the phase II study. In DPN 3‐1b, symptomatic relief was maintained for 8 months after the last injection suggesting that VM202 treatment might change disease progression. Despite the perplexing discrepancy between the two studies, the safety and long‐lasting pain‐relieving effects of VM202 observed in DPN 3‐1b warrant another rigorous phase III study. Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Current therapies for painful diabetic peripheral neuropathy (DPN) are palliative and do not target the underlying mechanisms. Moreover, symptomatic relief is often limited with existing neuropathic pain drugs. Thus, there is a great medical need for safer and effective treatments for DPN.

• WHAT QUESTION DID THIS STUDY ADDRESS?

Can nonviral gene delivery of hepatocyte growth factor reduce pain in patients with DPN and potentially modify progression of the disorder?

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Nonviral gene therapy can be used safely and practically to treat DPN.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

As the first gene medicine to enter advanced clinical trials for the treatment of DPN, this study provides the proof of concept of an entirely new potential approach to the disorder.     

转染癌基因的骨髓基质干细胞体外分化特征

目的:观察转染癌基因的骨髓基质干细胞在体外分化情况,为肝细胞癌的细胞源研究提供实验依据。方法:实验于2003-05/2004-06在南方医科大学药理教研室实验室完成。①两步法获取大鼠肝细胞,梯度离心法分离大鼠骨髓基质干细胞。②单基因转染是单独将c-myc或K-ras癌基因瞬时转染大鼠骨髓基质干细胞,6孔培养板中培养,24h后荧光显微镜下观察骨髓基质干细胞转染结果。双基因转染步骤相同,只是将c-myc和K-ras癌基因同时转染大鼠骨髓基质干细胞。③c-myc癌基因转染组、K-ras癌基因转染组、双癌基因转染组常规培养,加入含体积分数为0.1胎牛血清的DMEM培养基,于37℃、体积分数为0.05的CO2孵箱培养,每24h半量更换培养液。④c-myc癌基因转染 肝细胞组、K-ras癌基因转染 肝细胞组、双癌基因转染 肝细胞组将已转染癌基因的骨髓基质干细胞,置于叠加的培养板半透膜的上方(细胞密度均为1×105个/cm2),再将肝细胞置于半透膜的下方(每孔细胞密度为3×105/cm2)进行共培养,其余步骤同常规培养。⑤通过反转录聚合酶式反应和细胞免疫组化检测骨髓基质干细胞分化情况。结果:①癌基因转染24h骨髓基质干细胞检测结果:单独转染c-myc或K-ras癌基因的细胞,其绿色荧光蛋白呈均匀一致分布;双基因转染的细胞,绿色荧光蛋白呈点片状分布。②各组骨髓基质干细胞向肿瘤细胞分化检测结果:c-myc癌基因转染组、K-ras癌基因转染组、双癌基因转染组的骨髓基质干细胞,均未向肿瘤细胞分化;c-myc癌基因转染 肝细胞组、K-ras癌基因转染 肝细胞组、双癌基因转染 肝细胞组的骨髓基质干细胞,均向肝细胞癌发展;空白对照组骨髓基质干细胞细胞均为阴性。此外,双癌基因转染 肝细胞组的骨髓基质干细胞分化增殖迅速,反转录聚合酶式反应和免疫组化检测发现,培养第7天出现甲胎蛋白表达,并迅速增加,而第7天出现的白蛋白和细胞角蛋白18表达迅速减弱,第14天消失。结论:转染癌基因的骨髓基质干细胞,在向肝细胞诱导的条件下,部分癌基因可以使干细胞分化为肝癌细胞;多癌基因转染时,更易于使干细胞分化为肝癌细胞。     

Annexin V for flow cytometric detection of phosphatidylserine expression on B cells undergoing apoptosis

Apoptosis, or programmed cell death, is a general mechanism for removal of unwanted cells from the immune system. It is characterized by chromatin condensation, a reduction in cell volume, and endonuclease cleavage of DNA into oligonucleosomal length fragments. Apoptosis is also accompanied by a loss of membrane phospholipid asymmetry, resulting in the exposure of phosphatidylserine at the surface of the cell. Expression of phosphatidylserine at the cell surface plays an important role in the recognition and removal of apoptotic cells by macrophages. Here we describe a new method for the detection of apoptotic cells by flow cytometry, using the binding of fluorescein isothiocyanate-labeled annexin V to phosphatidylserine. When Burkitt lymphoma cell lines and freshly isolated germinal center B cells are cultured under apoptosis inducing conditions, all cells showing chromatin condensation strongly stain with annexin V, whereas normal cells are annexin V negative. Moreover, DNA fragmentation is only found in the annexin V-positive cells. The nonvital dye ethidium bromide was found to stain a subpopulation of the annexin V-positive apoptotic cells, increasing with time. Our results indicate that the phase in apoptosis that is characterized by chromatin condensation coincides with phosphatidylserine exposure. Importantly, it precedes membrane damage that might lead to release from the cells of enzymes that are harmful to the surrounding tissues. Annexin V may prove important in further unravelling the regulation of apoptosis.     

Serologic test for syphilis as a surrogate marker for human immunodeficiency virus infection among United States blood donors

BACKGROUND: This study evaluated the usefulness of the serologic test for syphilis (STS) in preventing the transmission of human immunodeficiency virus (HIV), hepatitis B and C viruses, and human T- lymphotropic virus via the transfusion of seronegative, infectious window-period blood. STUDY DESIGN AND METHODS: Demographic and laboratory information on blood donations made between January 1992 and June 1994 in 18 American Red Cross regions was analyzed. It was assumed that the same proportion of HIV-positive and HIV-infectious window- period donations reacted on STS and were negative on other screening tests (hepatitis B and C viruses and human T-lymphotropic virus). This proportion multiplied by the estimated number of HIV-infectious window- period donations is the number of post-screening HIV-infectious donations removed by STS. RESULTS: Of 4,468,570 donations, 12,145 (0.27%) were STS positive and 377 (0.008%) were HIV positive. Among donations that were negative on other screening tests, STS-reactive donations were 12 times more likely to be HIV positive (odds ratio = 11.9; 95% CI = 5,26). However, of an estimated 13 infectious window- period donations, 0.2 would have been removed because of a reactive STS, at a cost of over $16 million. CONCLUSION: STS is a poor marker and a costly strategy for preventing post-screening HIV infections and other blood-borne diseases.     

Polycystic Kidney Disease Re-evaluated: A Population-based Study

A genetic register of all known cases of autosomal dominantpolycystic kidney disease occurring in South and Mid-Wales hasbeen established. In a population of 2.1 million, 209 familieswith affected members were identified, 303 of whom are currentlyalive, 70 on renal replacement therapy. An additional 551 caseswould be predicted amongst family members at 50 per cent and25 per cent risk, giving an apparent prevalence of 1:2459 inthe general population. Five possible new mutations were seenwhere adults with phenotypic autosomal dominant polycystic kidneydisease had both parents alive, age > 55 years with no cystsvisible on ultrasound. The take-on rate for renal replacementtherapy increased during 1970–79 but has apparently reacheda plateau of 4.8 cases per million population per year overthe last 8 years, despite a rapidly increasing acceptance ofuraemic patients as a whole (72/10⁶/year in 1988–89).Considerably more patients with autosomal dominant polycystickidney disease aged over 50 years were started on treatmentin 1980–89 than in 1970–79, but the survival overallimproved with time. All cases of autosomal dominant polycystickidney disease reaching end-stage renal disease are now beingtreated, but the apparent clinical prevalence of this conditionin our region is less than half the supposed gene frequency,suggesting that undiagnosed cases have a benign prognosis.