血管紧张素原基因5’端启动子区A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压的相关性

目的:分析血管紧张素原基因启动子区A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压的相关性。方法:实验于2005-08/2006-01在北京华大实验室完成。选取对象均为生活在内蒙古乌拉特后旗的蒙古族牧民,三代血亲内无其他民族。采用基因测序技术对内蒙古蒙古族人群中107例原发性高血压患者和108例正常对照者进行A-20C和A-6G基因分型,观察高血压组和正常对照组不同基因型的分布和等位基因频率的差异。结果:①两组受试者在性别、年龄及吸烟、饮酒、体质量指数和临床化验检查指标有较好的匹配(P均>0.05)。②两组血管紧张素原基因A-20C位点AA,AC,CC基因型频率比较差异无显著性意义(高血压组分别为0.51,0.29,0.20;正常对照组分别为0.49,0.28,0.23,χ2=0.395,P=0.529)。A,C等位基因频率比较差异无显著性意义(高血压组分别为0.65,0.35;正常对照组分别为0.63,0.37,χ2=0.015,P=0.904)。③两组血管紧张素原基因A-6G位点AA,AG,GG基因型频率比较差异无显著性意义(高血压组分别为0.50,0.33,0.17;正常对照组分别为0.55,0.34,0.11,χ2=1.924,P=0.165)。A,G等位基因频率比较差异无显著性意义(高血压组分别为0.66,0.34;正常对照组分别为0.72,0.28,χ2=1.728,P=0.189)。④高血压组协同存在血管紧张素原基因A-20C基因型CC时,血管紧张素原基因A-6G基因型GG频率稍高于正常对照组,但差异无显著性意义(χ2=2.395,P=0.122,OR=7.52,95%CI0.014～1.250),高血压组G等位基因明显高于正常对照组(分别为0.37,0.22,χ2=4.658,P=0.034),携带该等位基因的蒙古族人群发生原发性高血压的相对危险度升高(OR=2.80,95%CI1.087～7.271)。结论:血管紧张素原基因A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压相关,并可能具有协同作用。     

Clinical correlates of low-risk variants in FGFR2, TNRC9, MAP3K1, LSP1 and 8q24 in a Dutch cohort of incident breast cancer cases

Introduction

Seven SNPs in five genomic loci were recently found to confer a mildly increased risk of breast cancer.

Methods

We have investigated the correlations between disease characteristics and the patient genotypes of these SNPs in an unselected prospective cohort of 1,267 consecutive patients with primary breast cancer.

Results

Heterozygote carriers and minor allele homozygote carriers for SNP rs889312 in the MAP3K1 gene were less likely to be lymph node positive at breast cancer diagnosis (P = 0.044) relative to major allele homozygote carriers. Heterozygote carriers and minor allele homozygote carriers for SNP rs3803662 near the TNCR9 gene were more likely to be diagnosed before the age of 60 years (P = 0.025) relative to major allele homozygote carriers. We also noted a correlation between the number of minor alleles of rs2981582 in FGFR2 and the average number of first-degree and second-degree relatives with breast cancer and/or ovarian cancer (P = 0.05). All other disease characteristics, including tumour size and grade, and oestrogen or progesterone receptor status, were not significantly associated with any of these variants.

Conclusion

Some recently discovered genomic variants associated with a mildly increased risk of breast cancer are also associated with breast cancer characteristics or family history of breast cancer and ovarian cancer. These findings provide interesting new clues for further research on these low-risk susceptibility alleles.     

Prospective development of an individualised predictive model for treatment coverage using offline cone beam computed tomography surrogate measures in post‐prostatectomy radiotherapy

The aim of this study is to prospectively evaluate and model surrogate explanatory variables (SEVs) of target coverage and rectal dose pertaining to soft tissue anatomy visualised on cone beam computed tomography (CBCT) for incorporation into post‐prostatectomy treatment coverage verification protocols. Twenty post‐prostatectomy patients treated with conformal prostate bed radiotherapy (64–74 Gy) underwent CBCT daily at fractions 1 to 5, and then weekly. Treatment coverage was defined on each CBCT using ‘PTV95’, percentage of the CBCT PTV covered by original treatment fields, and ‘RECTD50’, dose delivered to 50% of CBCT rectal volume by original treatment fields. Three candidate SEVs for treatment coverage were defined for each scan: anterior rectal wall movement, change in bladder length and bladder base movement. Both anterior rectal wall movement and increase in bladder length predicted for the decreased PTV95 (P < 0.001 for each). Anterior movement of the anterior rectal wall predicted for increased RECTD50 (P < 0.001). Predictive models for the PTV95 and RECTD50 that accept the significant SEVs as inputs were developed. We developed simple CBCT‐acquired soft tissue anatomic surrogate measures that signal changes in target coverage and rectal dose during post‐prostatectomy radiotherapy. Conventional bony anatomy patient position verification protocols were inadequate in accounting for soft tissue target and organ variation seen with CBCT.     

Identification of women with an increased risk of developing radiation-induced breast cancer: a case only study

Introduction

Medroxyprogesterone acetate (MPA) induces estrogen receptor (ER)-positive and progesterone receptor (PR)-positive ductal invasive mammary carcinomas in BALB/c mice. We sought to reproduce this MPA cancer model in C57BL/6 mice because of their widespread use in genetic engineering. Within this experimental setting, we studied the carcinogenic effects of MPA, the morphologic changes in mammary glands that are induced by MPA and progesterone, and the levels of ER and PR expression in MPA-treated and progesterone-treated mammary glands. Finally, we evaluated whether the differences found between BALB/c and C57BL/6 mouse strains were due to intrinsic differences in epithelial cells.

Methods

The carcinogenic effect of MPA was evaluated in C57BL/6 mice using protocols proven to be carcinogenic in BALB/c mice. In addition, BALB/c and C57BL/6 females were treated with progesterone or MPA for 1 or 2 months, and mammary glands were excised for histologic studies and for immunohistochemical and Western blot evaluation of ER and PR. Hormone levels were determined by radioimmunoassay. Isolated mammary epithelial cells were transplanted into cleared fat pads of 21-day-old female Swiss nu/nu mice or control congenic animals.

Results

MPA failed to induce mammary carcinomas or significant morphologic changes in the mammary glands of C57BL/6 mice. The expression of ER-α and PR isoform A in virgin mice was surprisingly much higher in BALB/c than in C57BL/6 mammary glands, and both receptors were downregulated in progestin-treated BALB/c mice (P < 0.05). PR isoform B levels were low in virgin control mice and increased after progestin treatment in both strains. ER-β expression followed a similar trend. No differences in hormone levels were found between strains. Surprisingly, the transplantation of the epithelial mammary gland cells of both strains into the cleared fat pads of Swiss (nu/nu) mice abolished the mammary gland morphologic differences and the ER and PR differences between strains.

Conclusion

C57BL/6 mammary glands are resistant to MPA-induced carcinogenesis and to hormone action. MPA and progesterone have different effects on mammary glands. Low ER-α and PR-A levels in untreated mammary glands may be associated with a low-risk breast cancer profile. Although we cannot at this time rule out the participation of other, untested factors, our findings implicate the stroma as playing a crucial role in the strain-specific differential hormone receptor expression and hormone responsiveness.     

Pathway analysis of gene signatures predicting metastasis of node-negative primary breast cancer

Background  

Published prognostic gene signatures in breast cancer have few genes in common. Here we provide a rationale for this observation by studying the prognostic power and the underlying biological pathways of different gene signatures.     

Panel expertise for an Angoff standard setting procedure in progress testing: item writers compared to recently graduated students

INTRODUCTION: An earlier study showed that an Angoff procedure with > or = 10 recently graduated students as judges can be used to estimate the passing score of a progress test. As the acceptability and feasibility of this approach are questionable, we conducted an Angoff procedure with test item writers as judges. This paper reports on the reliability and credibility of this procedure and compares the standards set by the two different panels. METHODS: Fourteen item writers judged 146 test items. Recently graduated students had assessed these items in a previous study. Generalizability was investigated as a function of the number of items and judges. Credibility was judged by comparing the pass/fail rates associated with the Angoff standard, a relative standard and a fixed standard. The Angoff standards obtained by item writers and graduates were compared. RESULTS: The variance associated with consistent variability of item writers across items was 1.5% and for graduate students it was 0.4%. An acceptable error score required 39 judges. Item-Angoff estimates of the two panels and item P-values correlated highly. Failure rates of 57%, 55% and 7% were associated with the item writers' standard, the fixed standard and the graduates' standard, respectively. CONCLUSION: The graduates' and the item writers' standards differed substantially, as did the associated failure rates. A panel of 39 item writers is not feasible. The item writers' passing score appears to be less credible. The credibility of the graduates' standard needs further evaluation. The acceptability and feasibility of a panel consisting of both students and item writers may be worth investigating.     

Initiating activity of the anti-estrogen tamoxifen, but not toremifene in rat liver

A striking difference between two structurally related anti-estrogen medicines is that tamoxifen is strongly hepatocarcinogenic in the rat, whereas toremifene lacks such activity. To study the basis for this difference, the initiating potential of tamoxifen and toremifene were studied by measurement of rapid induction of hepatocellular altered foci (HAF) that express placental-type glutathione S-transferase in the livers of female Sprague-Dawley (S-D) rats and female Fischer 344 (F344) rats. Both agents were administered by gavage at equimolar doses up to a dose that produced marked weight gain suppression. In rats given the high dose of 40 mg/kg per day tamoxifen continuously for 36 weeks, 75% of S-D rats developed liver neoplasms, in contrast to only 10% of F344 rats. In the S-D strain, tamoxifen produced a tendency to increased HAF at 2 weeks at the dose of 40 mg/kg per day and by 12 weeks, a dose-related increase was evident. In contrast, toremifene induced no HAF even at the equimolar high dose of 42.4 mg/kg per day for 12 weeks. The induction of HAF by tamoxifen was less in the F344 rats. Neither agent elicited increases in hepatocellular proliferation in S-D or F344 rats. When phenobarbital was administered for 24 weeks as a promoting agent after the anti-estrogens, S-D rats given tamoxifen at 20 mg/kg per day for 12 weeks, developed liver neoplasms, but not F344 rats or rats of either strain given even a higher dose (42.4 mg/kg) of toremifene. Thus, tamoxifen has initiating activity in these rat strains whereas toremifene does not.      

Sarcomatoid renal cell carcinoma: Rapid dissemination detected on FDG PET‐CT

We present the FDG PET‐CT findings in a patient with persistent pain 7 weeks after a nephrectomy and lymph node dissection for a sarcomatoid renal cell carcinoma. Although conventional imaging was unable to detect evidence of metastatic spread outside the para‐aortic nodes, a PET‐CT scan showed unexpected extensive dissemination. Currently, there are no reports in the literature of the PET‐CT findings in sarcomatoid renal cell carcinomas.     

Diet and cancer prevention: the fiber first diet

Diet can play a major role in cancer prevention. The international differences in cancer incidence are largely accounted for by lifestyle practices that include nutrition, exercise, and alcohol and tobacco use. About 50% of cancer incidence and 35% of cancer mortality in the U.S., represented by cancers of the breast, prostate, pancreas, ovary, endometrium, and colon, are associated with Western dietary habits. Cancer of the stomach, currently a major disease in the Far East, relates to distinct, specific nutritional elements such as excessive salt intake. For these cancers, information is available on possible initiating genotoxic factors, promoting elements, and prophylactic agents. In general, the typical diet in the United States contains low levels of the potent carcinogenic agents, heterocyclic amines, formed during the cooking of meats. It provides only about half the potent appropriate fiber intake and is high in calories. About twice as many calories as would be desirable come from fat, certain kinds of which enhance the development of cancers. Other foods with functional properties, such as soy products and tea, can be beneficial. To achieve reduction in risk of certain cancers, diet must be optimized, primarily to reduce caloric intake and the fat component. The latter should be 20% or less of total caloric intake and fiber should be increased to 25- 35 g per day for adults. One approach to achieving these goals is the Fiber First Diet, a diet designed around adequate fiber intake from grains, especially cereals, vegetables, legumes, and fruits, which thereby reduces both calorie and fat intake. Such dietary improvements will not only reduce cancer and other chronic disease risks, but will contribute to a healthy life to an advanced age. A corollary benefit is a lower cost of medical care.      

麦冬类中药组织切片计算机三维重建图鉴

利用计算机技术实现麦冬类中药组织连续切片三维重建与动态显示,为计算机辅助生药学鉴定和教学提供了新的三维图像技术和研究资料。