Vitamin E and cancer prevention: Studies with different forms of tocopherols and tocotrienols

α-Tocopherol (α-T) is the major form of vitamin E (VE) in animals and has the highest activity in carrying out the essential antioxidant functions of VE. Because of the involvement of oxidative stress in carcinogenesis, the cancer prevention activity of α-T has been studied extensively. Lower VE intake or nutritional status has been shown to be associated with increased cancer risk, and supplementation of α-T to populations with VE insufficiency has shown beneficial effects in lowering the cancer risk in some intervention studies. However, several large intervention studies with α-T conducted in North America have not demonstrated a cancer prevention effect. More recent studies have centered on the γ- and δ-forms of tocopherols and tocotrienols (T3). In comparison with α-T, these forms have much lower systemic bioavailability but have shown stronger cancer-preventive activities in many studies in animal models and cell lines. γ-T3 and δ-T3 generally have even higher activities than γ-T and δ-T. In this article, we review recent results from human and laboratory studies on the cancer-preventive activities of different forms of tocopherols and tocotrienols, at nutritional and pharmacological levels. We aim to elucidate the possible mechanisms of the preventive actions and discuss the possible application of the available information for human cancer prevention by different VE forms.     

大狼毒三萜类化学成分的研究

自大戟科(Euphorbiaceae)植物大狼毒(Euphorbia nematocypha Hand—Mazz)根的乙醇提取物的苯溶解部分,经20%AgNO₃硅胶层析,分离得到七个三萜类成分。根据光谱(IR,EIMS,¹H—NMR和¹³C—NMR)和化学方法,确定其中一个化合物为新化合物,命名为大狼毒醇(nematocyphol,Ⅳa),其它化合物为已知物:印度荆芥醇乙酸酯(nepehinol acetate Ⅰ),日尔曼醇乙酸酯(germanicol acetate Ⅱ),大戟醇(euphol,Ⅲ),蒲公英醇(taraxasterol,Ⅴa),24-亚甲基环阿尔廷醇(24-methylenecycloartanol,Ⅴa)和印度荆芥醇(nepehinol,Ⅶa)。这些化合物均为首次从大狼毒中得到。     

顺-3-甲基芬太尼的4-N-丙酰基结构类似物的合成与镇痛活性及构效关系的研究

以不同电性的基团取代顺-3-甲基芬太尼中4-N-丙酰基上的乙基,合成某些顺-3-甲基芬太尼的结构类似物。药理试验结果表明,所合成的化合物均有典型的吗啡样作用。化合物3的镇痛活性略强于顺-3-甲基芬太尼。应用半经验的INDO方法对4个代表化合物进行了量子化学计算,讨论了电子结构与镇痛活性间的关系,化合物3由于氯乙烯基的引入具有与顺-3-甲基芬太尼不同的电子结构特征,氯乙烯基可能作为电子接受体参与了与受体的作用。     

顺-3-甲基芬太尼的4-N-丙酰基结构类似物的合成与镇痛活性及构效关系的研究

以不同电性的基团取代顺-3-甲基芬太尼中4-N-丙酰基上的乙基,合成某些顺-3-甲基芬太尼的结构类似物。药理试验结果表明,所合成的化合物均有典型的吗啡样作用。化合物3的镇痛活性略强于顺-3-甲基芬太尼。应用半经验的INDO方法对4个代表化合物进行了量子化学计算,讨论了电子结构与镇痛活性间的关系,化合物3由于氯乙烯基的引入具有与顺-3-甲基芬太尼不同的电子结构特征,氯乙烯基可能作为电子接受体参与了与受体的作用。     

一阶导数光谱法测定盐酸地尔硫缓释片的含量

目的:建立测定盐酸地尔硫艹卓缓释片的含量测定方法。方法:以乙醇为溶剂,以一阶导数光谱的谷-零位值法测定盐酸地尔硫艹卓的含量,测定波长λ谷=2 50±1nm。结果:回收率100.01% ,RSD0.38%～0.47% ,线性范围2.4～16.8μg/ml。结论:方法简便、快速、准确,适合于该制剂的含量测定。     

Dose optimization of fractionated external radiation and high-dose-rate intracavitary brachytherapy for FIGO stage IB uterine cervical carcinoma

: To determine the optimal dose combination scheme of external beam radiotherapy (EBRT) and high-dose-rate (HDR) intracavitary radiation (ICR) for maximizing tumor control while conferring an acceptable late complication rate in the treatment of Stage IB uterine cervical cancer.

: We retrospectively analyzed 162 patients with International Federation of Gynecology and Obstetrics (FIGO) Stage IB squamous cell carcinoma of the uterine cervix who received definitive RT between May 1979 and December 1990. Before HDR-ICR, all patients received EBRT to a total dose of 40–46 Gy (median 45), administered during 4–5 weeks to the whole pelvis. HDR-ICR was given 3 times weeks to a total dose of 24–51 Gy (median 39) at point A, using a dose of 3 Gy/fraction. Central shielding from EBRT was begun after the delivery using 20–45 Gy (median 40) of the external dose. The total dose to point A, calculated by adding the EBRT biologically effective dose (BED) and the ICR BED to point A, was 74.1–118.1 Gy (mean 95.2). The rectal point dose was calculated at the anterior rectal wall at the level of the cervical os. The local control rate, survival rate, and late complication rate were analyzed according to the irradiation dose and BED.

: The initial complete response rate was 99.4%. The overall 5-year survival rate and 5-year disease-free survival rate was 91.1% and 90.9%, respectively. The local failure rate was 4.9%, and the distant failure rate was 4.3%. Late complications were mild and occurred in 23.5% of patients, with 18.5% presenting with rectal complications and 4.9% with bladder complications. The mean rectal BED (the sum of the external midline BED and the ICR rectal point BED) was lower in the patients without rectal complications than in those with rectal complications (125.6 Gy vs. 142.7 Gy, p = 0.3210). The late rectal complication rate increased when the sum of the external midline BED and the rectal BED by ICR was ≥131 Gy (p = 0.1962). However, 5-year survival rates did not increase with the external midline BED (p = 0.4093). The late rectal complication rate also increased, without a change in the survival rate, when the sum of the external midline BED and the ICR point A BED was >90 Gy.

: In treating Stage IB carcinoma of the uterine cervix with HDR-ICR, using fractions of 3 Gy, it is crucial to keep the point A BED at ≤90 Gy to minimize late rectal complications without compromising the survival rate. To achieve this goal, appropriate central shielding from EBRT is needed.     

Establishment and characterisation of six human biliary tract cancer cell lines

Human cell lines established from biliary tract cancers are rare, and only five have been reported previously. We report the characterisation of six new six biliary tract cancer cell lines (designated SNU-245, SNU-308, SNU-478, SNU-869, SNU-1079 and SNU-1196) established from primary tumour samples of Korean patients. The cell lines were isolated from two extrahepatic bile duct cancers (one adenocarcinoma of common bile duct, one hilar bile duct cancer), two adenocarcinomas of ampulla of Vater, one intrahepatic bile duct cancer (cholangiocarcinoma), and one adenocarcinoma of the gall bladder. The cell phenotypes, including the histopathology of the primary tumours and in vitro growth characteristics, were determined. We also performed molecular characterisation, including DNA fingerprinting analysis and abnormalities of K-ras, p15, p16, p53, hMLH1, hMSH2, DPC4, beta-catenin, E-cadherin, hOGG1, STK11, and TGF-betaRII genes by PCR-SSCP and sequencing analysis. In addition, we compared the genetic alterations in tumour cell lines and their corresponding tumour tissues. All lines grew as adherent cells. Population doubling times varied from 48-72 h. The culture success rate was 20% (six out of 30 attempts). All cell lines showed (i) relatively high viability; (ii) absence of mycoplasma or bacteria contamination; and (iii) genetic heterogeneity by DNA fingerprinting analysis. Among the lines, three lines had p53 mutations; and homozygous deletions in both p16 and p15 genes were found three and three lines, respectively; one line had a heterozygous missense mutation in hMLH1; E-cadherin gene was hypermethylated in two lines. Since the establishment of biliary tract cancer cell lines has been rarely reported in the literature, these newly established and well characterised biliary tract cancer cell lines would be very useful for studying the biology of biliary tract cancers, particularly those related to hypermethylation of E-cadherin gene in biliary tract cancer.     

Simultaneous determination of loxoprofen and its diastereomeric alcohol metabolites in human plasma and urine by a simple HPLC-UV detection method

A simple, reliable HPLC-UV detection method was developed for the simultaneous determination of loxoprofen and its metabolites (i.e. trans- and cis-alcohol metabolites), in human plasma and urine samples. The method involves the addition of a ketoprofen (internal standard) solution in methanol, zinc sulfate solution and acetonitrile to plasma and urine samples, followed by centrifugation. An aliquot of the supernatant was evaporated to dryness, and the residue reconstituted in a mobile phase (acetonitrile:water=35:65 v/v, pH 3.0). An aliquot of the solution was then directly injected into the HPLC system. Separations were performed on octadecylsilica column (250x4.5 mm, 5 microm) with a guard column (3.2x1.5 cm, 7 microm) at ambient temperature. Loxoprofen and the metabolites in the eluent were monitored at 220 nm (a.u.f.s. 0.005). Coefficients of variations (CV%) and recoveries for loxoprofen and its metabolites were below 10 and over 96%, respectively, in the 200 approximately 15000 ng ml(-1) range for plasma and 500 approximately 50000 ng ml(-1) range for urine. Calibration curves for all the compounds in the plasma and urine were linear over the above-mentioned concentration ranges with a common correlation coefficient of 0.999. The detection limit of the present method was 100 ng for all the compounds. These results indicate that the present method is very simple and readily applicable to routine bioavailability studies of these compounds with an acceptable sensitivity.     

P53 mediates ceramide-induced apoptosis in SKN-SH cells

Ceramide induces apoptotic cell death in a dose- and time-dependent manner in neuroblastoma SKN-SH cells. Pretreatment with caspase inhibitors blocks cell death, suggesting that a set of caspase activities including caspase 1, as well as caspase 3, are involved in ceramide-induced apoptosis in SKN-SH cells. Treatment with a caspase inhibitor 3 h after ceramide addition did not inhibit cell death, although caspase activity was substantially reduced. Ceramide-induced apoptosis is accompanied by accumulation of p53 followed by an increase of Bax and decrease of Bcl-2 levels. Inhibition of p53 expression with p53 antisense oligonucleotides inhibits apoptosis and prevents the increase in Bax and decrease in Bcl-2. Furthermore, pretreatment with p53 antisense oligonucleotides markedly inhibits the induction of caspase activity. These results suggest that p53 regulates the ratio Bcl-2/Bax and the expression/activation of caspases during ceramide-induced apoptosis in SKN-SH cells. Caspase inhibition did not alter the expression of p53, Bcl-2 and Bax. Thus ceramide-induced reduction in the Bcl-2/Bax ratio, increase in caspase activity, and apoptosis is dependent upon increases in cellular p53 levels which play a critical role in the regulation of apoptotic cell death.     

Prophylactic growth factor-primed donor lymphocyte infusion using cells reserved at the time of transplantation after allogeneic peripheral blood stem cell transplantation in patients with high-risk hematologic malignancies

BACKGROUND: Standard allogeneic bone marrow transplantation (BMT) offers only a small chance of cure for most adult patients with advanced hematologic malignancies. The authors postulated that allogeneic peripheral blood stem cell transplantation (PBSCT) followed by prophylactic growth factor-primed donor lymphocyte infusion (DLI) with cells reserved at harvest would maximize the graft-versus-tumor effects in patients with hematologic malignancies who had a high risk of recurrence. METHODS: Seventeen patients with hematologic malignancies who had a high risk of recurrence were allocated on an intent-to-treat basis to allogeneic PBSCT from human leukocyte antigen-matched sibling donors followed by prophylactic growth factor-primed DLI of cells reserved at harvest for transplantation. RESULTS: The median age was 37 years (range, 19-56 years). All donors underwent two or more apheresis procedures. The median numbers of mononuclear cells (MNCs), CD34 positive (CD34+) cells, and CD3+ cells, respectively, that were collected for 17 donors were 9.0 x 10(8) MNCs/kg (range, 4.9-14.4 x 10(8) MNCs/kg), 13.0 x 10(6) CD34+ cells/kg (range, 2.4-75.2 x 10(6) CD34+ cells/kg), and 5.8 x 10(8) CD3+ cells/kg (range, 3.3-9.9 x 10(8) CD3+ cells/kg) for a mean number of 2.35 apheresis procedures (range, 2.0-4.0 procedures). The median numbers of MNCs and CD3+ cells that were cryopreserved were 2.1 x 10(8) MNCs/kg (range, 0.0-4.4 x 10(8) MNCs/kg) and 1.4 x 10(8) CD3+ cells/kg (range, 0.0-3.5 x 10(8) CD3+ cells/kg). Seven of 17 patients received additional PBSCs, with a median of 5.0 x 10(7) CD3+ cells/kg (range, 3.0-9.9 CD3+ cells/kg) between Day 41 and Day 120. The reasons for inability to administer additional PBSCs in 10 patients included early death (n = 4 patients), severe graft-versus-host disease (GVHD) (n = 3 patients), disease recurrence (n = 2 patients), and harvest failure (n = 1 patient). Of seven patients, two patients died of recurrence, and one died of cytomegalovirus pneumonitis. The surviving four patients were free of disease when last assessed (median follow-up, 597 days) but were suffering from chronic GVHD (one patient had limited GVHD, and three patients had extensive GVHD). CONCLUSIONS: The authors suggest that allogeneic PBSCT with prophylactic growth factor-primed DLI may be a potentially curative strategy for the treatment of hematologic malignancies in patients with a high risk of recurrence. Their approach may offer the additional advantage of collecting enough cells at harvest for the potential use of DLI, which is easy, convenient for donors, and cost effective.