Folate intake and bowel cancer risk

Folate is a B vitamin required for one-carbon transfer reactions including methylation of cell macromolecules including DNA and synthesis of the purines adenosine and guanosine and the pyrimidine thymidine. Epidemiological evidence suggests that diets providing higher amounts of folates lower the risk of colo-rectal cancer (CRC) and these observations are supported by plausible biological mechanisms. Inadequate folate supply results in DNA damage through (a) the incorporation of uracil (in place of thymidine) into DNA and subsequent unsuccessful attempts at DNA repair and (b) aberrant patterns of DNA methylation. However, human intervention studies using relatively large doses (500–5,000 μg/day) of folic acid (a synthetic form of folate) have provided no evidence of benefit in terms of adenoma recurrence. Indeed, there is some evidence of potential harm in increased risk of prostate cancer. Possible reasons for the apparent divergence in findings from the observational and intervention studies include the use of (unphysiologically) large doses of folic acid in the intervention studies whereas smaller intakes of food folates appeared to offer “protection” against CRC in case–control and prospective cohort studies. With intakes of folic acid greater than 400 μg/day, unmetabolised folic acid appears in peripheral blood and there are suggestions that this folic acid may have adverse effects e.g. reduced cytotoxicity of Natural Killer cells. Until the benefit-risk relationship associated with mandatory fortification with folic acid has been clarified (and, in particular, the possible risk of inducing extra cases of bowel or other cancer), it would seem wise to delay further mandatory folic acid fortification.     

Early development, pattern, and reorganization of the planula nervous system in Aurelia (Cnidaria, Scyphozoa)

We examined the development of the nervous system in Aurelia (Cnidaria, Scyphozoa) from the early planula to the polyp stage using confocal and transmission electron microscopy. Fluorescently labeled anti-FMRFamide, antitaurine, and antityrosinated tubulin antibodies were used to visualize the nervous system. The first detectable FMRFamide-like immunoreactivity occurs in a narrow circumferential belt toward the anterior/aboral end of the ectoderm in the early planula. As the planula matures, the FMRFamide-immunoreactive cells send horizontal processes (i.e., neurites) basally along the longitudinal axis. Neurites extend both anteriorly/aborally and posteriorly/orally, but the preference is for anterior neurite extension, and neurites converge to form a plexus at the aboral/anterior end at the base of the ectoderm. In the mature planula, a subset of cells in the apical organ at the anterior/aboral pole begins to show FMRFamide-like and taurine-like immunoreactivity, suggesting a sensory function of the apical organ. During metamorphosis, FMRFamide-like immunoreactivity diminishes in the ectoderm but begins to occur in the degenerating primary endoderm, indicating that degenerating FMRFamide-immunoreactive neurons are taken up by the primary endoderm. FMRFamide-like expression reappears in the ectoderm of the oral disc and the tentacle anlagen of the growing polyp, indicating metamorphosis-associated restructuring of the nervous system. These observations are discussed in the context of metazoan nervous system evolution.     

Embryonic development and metamorphosis of the scyphozoan <Emphasis Type="Italic">Aurelia</Emphasis>

We investigated the development of Aurelia (Cnidaria, Scyphozoa) during embryogenesis and metamorphosis into a polyp, using antibody markers combined with confocal and transmission electron microscopy. Early embryos form actively proliferating coeloblastulae. Invagination is observed during gastrulation. In the planula, (1) the ectoderm is pseudostratified with densely packed nuclei arranged in a superficial and a deep stratum, (2) the aboral pole consists of elongated ectodermal cells with basally located nuclei forming an apical organ, which is previously only known from anthozoan planulae, (3) endodermal cells are large and highly vacuolated, and (4) FMRFamide-immunoreactive nerve cells are found exclusively in the ectoderm of the aboral region. During metamorphosis into a polyp, cells in the planula endoderm, but not in the ectoderm, become strongly caspase 3 immunoreactive, suggesting that the planula endoderm, in part or in its entirety, undergoes apoptosis during metamorphosis. The polyp endoderm seems to be derived from the planula ectoderm in Aurelia, implicating the occurrence of “secondary” gastrulation during early metamorphosis.     

Near-infrared autofluorescence spectroscopy for in vivo identification of hyperplastic and adenomatous polyps in the colon

This study reports the implementation of an endoscope-based near-infrared (NIR) autofluorescence (AF) spectroscopy technique for in vivo differentiation of normal, hyperplastic and adenomatous colonic polyps during clinical colonoscopic examination. A total of 198 in vivo NIR AF spectra in the range of 810–1050 nm were acquired from colonic tissues (normal (n = 116); hyperplastic (n = 48); and adenomatous polyps (n = 34)) of 96 patients undergoing colonoscopic screening. Significant differences (p < 0.001, one-way analysis of variance (ANOVA)) in in vivo NIR AF intensity among normal, hyperplastic, and adenomatous polyps are observed. Multivariate statistical techniques, including principal components analysis (PCA) and linear discriminate analysis (LDA) together with the leave-one tissue site-out, cross-validation, were used to develop diagnostic algorithms for distinguishing adenomatous polyps from normal and hyperplastic colonic polyps based on NIR AF spectral features. The PCA–LDA modeling on in vivo colonic NIR AF dataset yields diagnostic sensitivities of 83.6%, 77.1%, and 88.2%; and specificities of 96.3%, 88.0%, and 92.1%, respectively, for classification of normal, hyperplastic and adenomatous colonic polyps. This work suggests that NIR AF spectroscopy associated with PCA–LDA algorithms has potential for in vivo diagnosis and detection of colonic precancer at colonoscopy.     

结直肠疾病临床特点的趋势分析

目的:通过分析患者的临床资料,探讨结直肠疾病的临床特点,为临床诊断和治疗提供参考。方法:回顾性分析我院肠镜室2012年5月-2013年4月(A)及2005年5月-2006年4月(B)两个时间段经电子肠镜检查的人群的性别、年龄及结直肠疾病的检出、息肉及癌的病变部位及病理类型情况。结果:两时间段结直肠器质性疾病发病率均较高,且A时间段比B时间段结直肠器质性疾病发病率升高(57.68%:45.13%),结直肠息肉及炎发病率升高(35.09%:19.76%和21.90%:14.45%),腺瘤性息肉比率升高(76.84%:68.33%),左半结肠息肉及癌的比率降低(60.88%:72.27%和60.00%:77.55%)。结论:结直肠疾病的发病人群分布发生改变,发病率呈逐年升高趋势。结直肠息肉的病理分型、发生部位及结直肠癌的发生部位有显著变化。     

Short term viability of soft tissue detached from the skeleton of reef-building corals

We have induced soft tissue detachment from the skeleton of two colonial hard corals of the Pocilloporid family, both in vivo and in vitro. A parallel was made between polyp “bail-out”, i.e. field and laboratory-observed detachment of tissue fragments alone from the skeleton, and the dissociation method used for initiation of coral primary cell cultures. The in vitro approach provided insights into the active cellular re-arrangement mechanisms underlying coral tissue detachment. Functional polyps were not regenerated. Viability of tissue isolates detached from coral skeleton was probed for their use as a model for short-term biological assays. Cell viability dropped from 70% to 30% within the first week maintenance in vitro. Short-term isolate cultures limited to 3 days are a compromise allowing attachment of coral cells, yet preserving viability at about 70% of the total coral cell population.     

TNF-α在宫颈息肉组织中的表达及意义

目的:检测宫颈息肉组织中肿瘤坏死因子TNF-α的表达,并探讨其在宫颈息肉发病机制中的作用.方法:对150例患者宫颈息肉组织及137例宫颈管内膜组织分别进行TNF-α免疫组织化学染色和免疫印迹检测.结果:免疫组化检查发现TNF-α主要表达在宫颈息肉组织中的浆细胞胞质内,与对照组的表达比较差异有统计学意义(t值分别为2.258,P值均＜0.05).而且免疫印迹检查发现TNF-α蛋白在宫颈息肉组织中特异性表达强度高于对照组.结论:TNF-α在宫颈息肉组织中表达增高,对其发病起着一定的作用.     

The potential importance of podocysts to the formation of scyphozoan blooms: a review

Podocysts are cysts with stored reserves of organic compounds produced beneath the pedal discs of polyps of scyphozoans in the orders Rhizostomae (suborder Dactyliophorae) and Semaeostomae. They excyst small polyps that develop into fully active polyps (scyphistomae) capable of further podocyst production and of medusa production by strobilation. They contribute to increasing the number of polyps and also to survival through seasonal periods of reduced food availability or predation. These attributes may help support scyphozoan blooms, but as yet there are few quantitative data. Guest editors: K. A. Pitt & J. E. Purcell Jellyfish Blooms: Causes, Consequences, and Recent Advances     

子宫内膜息肉研究进展

子宫内膜息肉(endometrial polyps,EMP)由子宫内膜腺体和含有厚壁血管的纤维化内膜间质构成,是局部子宫内膜过度增生形成的有蒂或无蒂的赘生物。子宫内膜息肉是最常见的子宫内膜病变之一,临床表现为子宫不规则出血,或月经量增多、不孕、绝经后出血等,也可无明显临床症状。子宫内膜息肉多数属良性病变,但其可恶变性已经被证实。子宫内膜息肉的发病机制目前尚不明确,传统观点认为其与慢性子宫内膜炎症有关,属慢性炎症范畴,即为生物致炎因子及长期反复机械性刺激所致的反应性增生物;近年来随着分子生物学研究的深入,发现子宫内膜息肉的发生与可能与激素调控下增殖与凋亡失衡相关。近来随着宫腔镜检查技术的推广及激素补充治疗人数的增多,子宫内膜息肉的发病率及检出率逐渐增加,加之经刮宫或电切治疗后复发率非常高,因此,子宫内膜息肉越来越受到临床医生的重视,现将子宫内膜息肉的研究进展作一综述。     

巴布亚硝水母无性生殖过程及形态变化北大核心CSCD

以巴布亚硝水母(Mastigias papua)为研究对象,观察了水螅体无性生殖产生类浮浪幼虫胞芽、类浮浪幼虫胞芽变态发育为水螅体、水螅体横裂产生碟状体以及碟状体发育为水母体的过程和形态变化。25℃时类浮浪幼虫胞芽经过93 h后变态发育为水螅体。换用带有虫黄藻的天然海水并将培养温度从25℃升至27℃后,水螅体开始横裂,萼部触手环下方产生缢痕。水螅体横裂开始47 h后,缢痕更加明显,其上方部分发育为碟状幼体,后期碟状体搏动越来越频繁,最后释放。释放后的碟状体在实验室培养条件下21 d后可发育为水母幼体。巴布亚硝水母虽然只有产生类浮浪幼虫胞芽一种无性生殖方式,但繁殖速度较快,27℃时1个水螅体平均1 d可产生1.7个类浮浪幼虫胞芽,类浮浪幼虫胞芽可在3或4 d的短时间内附着变态。