4-羟基壬烯醛在糖尿病大鼠白内障中的代谢及发病中的作用

目的 研究脂质过氧化代谢产物4-羟基壬烯醛(HNE)在糖尿病性白内障中的代谢过程以及发病中的作用.方法 实验研究.采用两因素析因设计:处理因素为两水平(正常对照组和糖尿病组),时间因素为三水平(30、45、70 d).对于不同时期的正常与糖尿病大鼠晶状体采用下列方法进行处理:(1)使用一定晕的带有放射活性的HNE与这些晶状体一起培养,测定HNE在晶状体的代谢;(2)分光光度计法测定醛脱氢酶(ALDH)活性;(3)免疫印迹法检测ALDH和HNE-蛋白质加合物的表达.采用两因素析因设计定量资料方差分析对资料进行统计学处理.结果 HNE在正常对照组的晶状体的代谢主要是与谷胱甘肽(GSH)结合形成GS-HNE(约45%),其次为经ALDH氧化成HNA(约9.1%);但糖尿病组晶状体的HNE与GSH结合径路受到抑制,GS-HNE形成减少,与正常组相比30 d时减少约64%(F=49.59,P＜0.001);而糖尿病组晶状体的ALDH氧化径路代偿增强,HNA形成增多,70 d比30 d增多约1.7倍(F=11.51,P=0.0442).糖尿病组的晶状体ALDH活性增高,免疫印迹法显示ALDH较正常对照组增多,HNE-蛋白质加合物较对照组减少.结论糖尿病性白内障中HNE与GSH的结合径路受到抑制,而氧化径路代偿性增强,揭示了结合径路的损伤可能与白内障发生有密切关系,氧化径路的代偿增强可能对防止糖尿病性白内障的发生有一定的意义.(中华眼科杂志,2009,45:248-253)     

Impact of target point deviations on control and complication probabilities in stereotactic radiosurgery of AVMs and metastases.

OBJECTIVE: Determination of the impact of inaccuracies in the determination and setup of the target point in stereotactic radiosurgery (SRS) on the expectable complication and control probabilities. METHODS: Two randomized samples of patients with arteriovenous malformation (AVM) (n=20) and with brain metastases (n=20) treated with SRS were formed, and the probability for complete obliteration (COP) or complete remission (CRP), the size of the 10 Gy-volume in the brain tissue (VOI10), and the probability for radiation necrosis (NTCP) were calculated. The dose-effect relations for COP and CRP were fitted to clinical data. Target point deviations were simulated through random vectors and the resulting probabilities and volumes were calculated and compared with the values of the treatment plan. RESULTS: The decrease of the relative value of the control probabilities at 1mm target point deviation was up to 4% for AVMs and up to 10% for metastases. At 2 mm the median decrease was 5% for AVMs and 9% for metastases. The value for the target point deviation, at which COP and CRP decreased about 0.05 in 90% of the cases, was 1.3 mm. The increase of NTCP was maximally 0.0025 per mm target point deviation for AVMs and 0.0035/mm for metastases. The maximal increase of VOI10 was 0.7 cm(3)/mm target point deviation in both patient groups. CONCLUSIONS: The upper limit for tolerable target point deviations is at 1.3mm. If this value cannot be achieved during the system test, a supplementary safety margin should be applied for the definition of the target volume. A better accuracy level is desirable, in order to ensure optimal chances for the success of the treatment. The target point precision is less important for the minimization of the probability of radiation necroses.     

Pandora's box: ethics of PGD for inherited risk of late-onset disorders

Until recently, the primary use of preimplantation genetic diagnosis (PGD) has been the selection of embryos to avoid lethal or debilitating gene mutations or abnormal chromosome complement. PGD can be used to reduce the risk of transferring to the uterus an embryo with Down syndrome, and parents who are carriers of severe genetic diseases may choose to avoid having children with these debilitating genetic conditions. The use of PGD is now being extended to include gene mutations that increase the risk of late-onset disorders such as breast and ovarian cancer. This paper argues for caution in advocating reproductive methods that are costly, have a limited chance of success, and for which the long-term outcome is unknown. Counselling should allow women a true choice of declining the option of PGD without recrimination, feelings of guilt or social pressure. There is concern that the Human Fertilisation and Embryology Authority has approved extension of PGD to late-onset multifactorial diseases without clear guidelines for its use. Guidelines for embryo selection should be revised to deal with potential conflict between reproductive success and genetic screening for disorders that do not profoundly affect the embryo or the children.     

Efficacy of selected natural products as therapeutic agents against cancer

With emerging sophistication in the exploration of ocean environment, a number of marine bioactive products have been identified with promising anticancer activity. Many of these are in active phase I or phase II clinical trials or have been terminated because of adverse side effects, mainly hematological in nature. Nonetheless, the information derived has aided enormously in providing leads for laboratory synthesis with modifications in the parent structure affecting compound solubility, absorption, and toxicity, resulting in less severe toxicity while achieving maximum efficacy in smaller doses. We describe herein, a few of the compounds obtained from marine and terrestrial sources [bryostatin 1 ( 1), dolastatin 10 ( 2), auristatin PE ( 3), and combretastatin A4 ( 4)] that have been extensively investigated in our laboratory and continue to be investigated for their sensitization effects with other cytotoxic agents in several different site-specific tumors employing murine models or human subjects.     

Immobilization effect of Ruta graveolens L. on human sperm: a new hope for male contraception

AIM OF THE STUDY: Contraceptive plants which were introduced by folk in traditional remedies are investigated worldwide. In this study, the contraceptive effects of Ruta graveolens L., which has been mentioned for male contraceptive in Iranian traditional folk medicine, was experimented on human sperm. MATERIALS AND METHODS: Different doses of lyophilized aqueous extract of Ruta graveolens L. were added to an amount of fresh semen, containing 10(6) cells in a 1:1 volumic ratio. Motility and viability of cells, DNA status, mitochondrial activity and sperm revival tests were carried out. RESULTS: The sperm immobilization effects of the extract appeared immediately in a does-dependent manner and 100% of the sperms became immotile at a concentration of 100mg/ml but other parameters were intact. After washing the sperms, motility was returned in 30.8+/-3.2% of the sperms, besides coiled tails in 38.6+/-5.5% of the treated cells, in comparison to 12.5+/-2.0% of the control group (p=0.001). The part of the extract, responsible for immobilization of the sperms was stable upon boiling. CONCLUSIONS: As the cells were alive and immotile, probably some ionic currents are blocked by a thermostable component of the plant which can be promising as a new male channel blocker contraceptive.     

Impact of methylenetetrahydrofolate reductase (<Emphasis Type="Italic">MTHFR</Emphasis>) codon (677) and methionine synthase (<Emphasis Type="Italic">MS</Emphasis>) codon (2756) on risk of cervical carcinogenesis in North Indian population

Cervical cancer continues to be the most common cause of death among women in developing countries. Methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MS) are critical enzymes of folate metabolic pathways. In this work, we have conducted a case–control study to assess the role of these two polymorphisms in cervical cancer development. We obtained blood samples from 200 women with cervical cancer and from equal matched controls and analysed using PCR-RFLP method. We found that the methylenetetrahydrofolate reductase variant CT and CT + TT genotypes decreased cervix cancer risk, statistically significant (OR:0.30, 95% CI: 0.18–0.51, P < 0.001 for CT and OR:0.29, 95% CI: 0.18–0.49, P = 0.0000006 for CT + TT). Similarly in those patients who used oral contraceptive with variant CT genotype, there was statistically highly significant reduced risk of cervix cancer (OR:0.25, 95% CI: –0.12–0.49, P < 0.001) of methylenetetrahydrofolate reductase gene. For the methionine synthase, 2756 variant AG and AG + GG genotypes were similarly associated with highly significant reduced risk of cervix cancer (OR: 0.13, 95% CI: 0.07–0.26, P < 0.001 for AG, and OR: 0.15, 95% CI: 0.08–0.27, P < 0.001 for AG + GG) genotypes. In conclusion, our study suggested that methylenetetrahydrofolate reductase and methionine synthase polymorphisms might have protective effect on the risk of cervical cancer in the North Indian women.     

Deaths among young, single women in 2000-2001 in the West Bank, Palestinian Occupied Territories

A study in 2000-2001 of causes of death of women of reproductive age (15-49) in the West Bank, Palestinian Occupied Territories, found that 154 of the 411 deceased women aged 15-49 with known marital status were single. Death notification forms for reported deaths were analysed and verbal autopsies carried out, where possible, with relatives of the deceased women. We found important differences in the age at death and causes of death among the single and married women, which can be attributed to the disadvantaged social status of single women in Palestinian society, exacerbated by the current unstable political situation. 41% of the deceased single women were under 25 years of age at death compared to 8% of the married women. The proportion of violent deaths and suicides among the single women was almost twice as high as among the married women, mainly in those below age 25. The single women were also more likely to die from medical conditions which indicated that they faced barriers to accessing health care. The fieldwork was conducted at the height of the Intifada and the Israeli military response, with heavy restrictions on mobility, limiting the possibility of probing deeper into the circumstances surrounding sensitive deaths. More research into the socio-cultural context of single women in Palestine society is needed as a basis for intervention.