砷还原菌群对砷的还原作用及菌群的多样性分析

从砷污染土壤中富集砷抗性细菌,在厌氧环境中进行培养,观察其对砷的还原能力。结果表明：在21 h之内,As(V)就被完全还原为As(Ⅲ);培养72 h后,培养基中出现黄色沉淀,采用X射线衍射分析(XRD)和扫描电镜-能谱分析(SEM-EDS)技术对沉淀进行分析表明,沉淀主要是以3种晶型存在的硫化砷(AsS);培养150 h后,大约有65%的As以上述沉淀的方式从溶液中移除。此外,本文还采用了构建16S rDNA文库的方式对该体系中的微生物种群进行分析,利用RFLP技术对16S rDNA片段进行分型,共得到72个操作单元类型(OTU),其中6个OTU占了库容的51%,从这6个OTU中各选取1个克隆进行测序,结果表明,富集到的砷还原细菌属于喜热菌属(Caloramator)、梭菌属(Clostridium)和杆菌属(Bacillus)。     

实验猴直肠脱的防治

目的探索实验猴直肠脱的理想治疗方案。方法根据本中心治疗成功的经验对实验猴直肠脱的治疗方案、术后护理及预防措施进行了详细论述。结果经临床实践,本防治方案对实验猴直肠脱的治愈率可达90%以上。结论本方案可以在生产中推广应用。     

地衣芽胞杆菌活菌制剂联合庆大霉素预防伊立替康所致腹泻

目的观察地衣芽胞杆菌活菌制剂（整肠生胶囊）联合庆大霉素预防伊立替康（irinoteean,CPT-11）所致腹泻的疗效。方法31例接受含伊立替康方案化疗的晚期癌症患者,采用自身随机交叉对照的方法,分别于2个治疗周期接受化疗（对照组）、化疗＋整肠生胶囊＋庆大霉素（预防组）,比较腹泻及其他不良反应的差异。结果31例患者在2个治疗周期中,预防组较对照组腹泻发生率有显著降低（腹泻发生率分别为48．4％VS61．3％,P〈0．05;3／4级腹泻发生率分别为9．7％vs16．1％,P〈0．05）,且减少合并用药;同时骨髓抑制、食欲减退、恶心呕吐的发生率也有所降低（P〈0．05）,而2组便秘、肝肾功能异常差异无显著性。结论地衣芽胞杆菌活菌制剂联合庆大霉素能有效预防伊立替康所致腹泻。     

Rapid chemical reaction techniques developed for use in investigations of membrane-bound proteins (neurotransmitter receptors)

New techniques for investigating chemical reactions on cell surfaces in the microsecond-to-millisecond time region are described. Reactions mediated by membrane-bound neurotransmitter receptors that control signal transmission between 10¹² cells of the nervous system are taken as an example. Cells with receptors on their plasma membrane are equilibrated with photolabile, biologically inactive precursors of the neurotransmitters. Photolysis of these compounds releases free neurotransmitter that interacts with the receptors, leading to the transient opening of transmembrane receptor-formed channels that are permeant to small inorganic ions. The current thus induced can be measured. The technique can be used to measure the elementary steps of the receptor-mediated reactions. To illustrate the approach it was shown that an understanding of the mechanism of inhibition of the nicotinic acetylcholine receptor by the drug cocaine was obtained and led to the first proof that compounds exist that alleviate the inhibition.     

Breast cancer prevention--clinical trials strategies involving aromatase inhibitors

Estrogens and their metabolites have been implicated in both the initiation and the prevention of breast cancer. The reduction in breast cancer incidence seen in the tamoxifen arms of the four prospective trials to date has established the proof of principle that antagonizing estrogen is a potential means of reducing breast cancer risk. However, the areas to improve on these results include: (a) enhanced efficacy, (b) reduction in the incidence of receptor-negative tumors, (c) improved overall and endocrinological side effects, and (d) improved function on end-organs other than the breast. The aromatase inhibitors offer the potential to achieve these goals in part in the following ways: (a) greater reduction in risk of disease as evidenced by superior efficacy in advanced breast cancer and by inhibition of both initiation and promotion of breast cancer, (b) reduction in receptor-negative tumors by synergy with COX-2 inhibitors resulting in growth factor inhibition, anti-angiogenesis and inhibition of tumor-associated aromatase expression, (c) fewer vasomotor and urogenital abnormalities, and (d) reduced thromboembolism and cardiovascular complications and satisfactory effects on bone metabolism. Important differences may exist between non-steroidal reversible inhibitors and steroidal irreversible inactivators in particular related to the androgenic/anabolic effects of the steroidal inactivators. Pilot studies of aromatase inhibitors described elsewhere in this session have begun in healthy women with dense mammography, or a high-risk genetic and/or histocytopathologic profile, to determine potential efficacy, as well as effects on end-organ function. A number of phase three trials with aromatase inhibitors are also underway or in planning. Among these are the BRCA 1 and 2 study of exemestane versus placebo in unaffected postmenopausal carriers, the International Breast Intervention Study 2 (IBIS 2) of anastrozole versus placebo in women with a high-risk profile, and the National Cancer Institute of Canada’s Clinical Trial Group (NCIC CTG) study of exemestane with or without celecoxib versus placebo in women at risk of the disease. For premenopausal women, combination strategies of gonadotrophin agonists and aromatase inhibitors are being investigated. The potential of using low doses of aromatase inhibitors to lower “in breast” estrogen levels without unduly perturbing plasma concentrations is also being explored. The potential of the aromatase gene functioning as an oncogene within the breast may be tied to breast density which in turn may represent both a selection tool for elevated risk and an intermediate marker of prevention. The strong link between postmenopausal estrogen levels and breast cancer risk suggests the possibility that plasma estrogen levels may be a useful intermediate marker of prevention. The aromatase inhibitors offer us the first ever tool to render women virtually free of estrogen and are potentially an exciting tool for the prevention of breast cancer.     

纳米抗体在传染病的预防、诊断和治疗中的应用 *

传染病是一种由致病性微生物引起,能够影响人类身体健康甚至引发严重社会危机的传播性疾病。近年来,新冠、埃博拉等传染病的恶性暴发促使人们寻找更为高效便捷的防治手段以遏制疾病的进程。抗体在传染病防治中的应用引起了广泛关注,palivizumab是目前唯一被批准应用于呼吸道合胞病毒在免疫力低下人群的预防的单克隆抗体。纳米抗体(nano-antibody, Nb)是目前已知的能与抗原稳定结合的最小功能性单域抗体,具有稳定性高、亲水性强、易于表达和改造等优势。独特的分子特性使其在病毒、细菌、寄生虫等引发的传染病的预防、诊断和治疗中展现出良好的应用前景,相关研究显示纳米抗体对艾滋、流感、新型冠状病毒等都有很好的治疗效果。重点叙述纳米抗体的结构特点及其在传染性疾病中的研究进展。     

3',5'-Cyclic diguanylic acid (c-di-GMP) inhibits basal and growth factor-stimulated human colon cancer cell proliferation

The novel cyclic dinucleotide, 3',5'-cyclic diguanylic acid, cGpGp (c-di-GMP), is a naturally occurring small molecule that regulates important signaling mechanisms in prokaryotes. Recently, we showed that c-di-GMP has "drug-like" properties and that c-di-GMP treatment might be a useful antimicrobial approach to attenuate the virulence and pathogenesis of Staphylococcus aureus and prevent or treat infection. In the present communication, we report that c-di-GMP (50 microM) has striking properties regarding inhibition of cancer cell proliferation in vitro. c-di-GMP inhibits both basal and growth factor (acetylcholine and epidermal growth factor)-induced cell proliferation of human colon cancer (H508) cells. Toxicity studies revealed that exposure of normal rat kidney cells and human neuroblastoma cells to c-di-GMP at biologically relevant doses showed no lethal cytotoxicity. Cyclic dinucleotides, such as c-di-GMP, represent an attractive and novel "drug-platform technology" that can be used not only to develop new antimicrobial agents, but also to develop novel therapeutic agents to prevent or treat cancer.     

Alzheimer's disease and estrogen

The preventive effect of estrogen on Alzheimer's disease (AD) has become clear with epidemiological data. Therapeutic effects of estrogen have not yet been established. In this presentation, we report our new basic and clinical data. The estrogen receptor, (ER), and ERβ mRNA were investigated in rat brain. Estradiol-17β (E₂) treatment following OVX reduced the levels of ER mRNA in the hypothalamus. In the substantia innominata (SI), the number of choline acetyltransferase immunoreacive cells increased significantly in the estrogen treatment rat. The neurons in SI projecting to the forebrain cortex contained ER. Increasing amounts of intracellular calcium, peroxidation, and apoptosis with amyloid β were suppressed in neuronal cells from rat pheochromocytoma (PC12) cells with E₂. ER cDNA transfected PC 12 cells elaborated more neurite-like processes with E₂. In clinics, we are currently preparing vaginal progesterone tablets, which essentially may concentrate in the endometrium to prevent endometrial cancer, with few general circulation of progesterone inviting less depression. The therapeutic effects of cyclic estrogen, such as its preventive effect, are suggested in these studies, at least on mild AD.