有助改善人体健康的纳米生物科技

纳米技术是20世纪80年代末期兴起的新技术。此种新技术是指在1-100nm这一尺度范围内对原子和分子运动规律和特性进行研究和应用。通过直接操纵和安排原子、分子将物质转变成具有特殊性能的新材料的科学技术。纳米技术研究的最终目标是直接以原子和分子为起点，从纳米材料出发或采用纳米加工技术，制造出具有特殊功能的产品，从而改变人类的生产和生活模式。纳米科技保健产品对促进人类健康有积极作用。     

VACUOLE SIGN AND SMALL NODE SIGN IN EARLY PERIPHERAL LUNG CANCER PATHOLOGIC BASIS AND DIAGNOSTIC VALUE

Radiologic and pathologic mani;estations of 30 peripheral pulmonary masses around l.5-3 cm in dia- meter were compared to the pathologic basis of va- cuole sign and small node sign on tomogram. Stati stics of 100 conventional X-ray tomograms of peri- pheral pulmonary masses about l-3 cm in diameter suggested that the vacuole sign and small node sign, more common in early peripheral lung cancer than in tuberculoma, are valuable for differentiating early peripheral lung cancer from tuberculoma.     

宫颈粘液过氧化物酶在月经周期中的变化规律

本文对29例月经周期正常妇女的宫颈粘液过氧化物酶进行了30个周期的研究。在月经周期不同时间测定宫颈粘液过氧化物酶(CMPx)活性及血清促黄体生成素(LH)、雌二醇(E_2)和孕酮(P)。结果表明:在排卵前三天酶活性明显下降,至排卵后一天开始上升。卵泡期,酶活性与E_2呈负相关(r=-0.67);黄体期,酶活性与P呈正相关(r=0.79)。本研究提示:1.CMPx在排卵周期具有特定的变化规律,其变化受体内激素水平影响,可作为预告排卵的指标。2.如简化测定方法,可为自然避孕提供新途径。     

Preparation and characterization of porous beta-tricalcium phosphate/collagen composites with an integrated structure

Porous beta-tricalcium phosphate (TCP)/collagen composites with different beta-TCP/collagen weight ratio were prepared. The influences of the preparation conditions on the microstructure of porous composite and the joint status of beta-TCP particles with collagen fibrils were characterized by X-ray diffractometer, scanning electron microscopy and transmission electron microscopy. The results showed: (1) an acid treatment could effectively disassemble collagen fibrils; (2) in the resulting porous composites, beta-TCP particles homogenously existed on the skeleton of the collagen fibril network and bonded tightly to both the fibrils and themselves. The tight bonding formation could be due to the reaction between Ca ions in the particles and carboxyl groups in collagen polypeptide chains and due to the reprecipitation of partially dissolved beta-TCP during synthesis. The tight bonding between beta-TCP particles and collagen fibrils in the composites demonstrated an integrated structure, which was reproducible when beta-TCP/collagen ratio ranged from 2 to 4. Such integrated structure would make significant contributions in reliably tailoring properties of the porous composites by varying beta-TCP content. In addition, the porous composites had large porosity (approximately 95%) and appropriate pore size (approximately 100 microm), showed no negative impact in cytotoxicity assay and complete bone tissue regeneration after 12 weeks in animal test.     

Expression of geminin as a marker of cell proliferation in normal tissues and malignancies

Geminin interacts with a DNA replication initiation factor, Cdt1p, to suppress initiation of DNA replication in a Xenopus egg extract based cell-free system, leading to the expectation that the protein acts as an inhibitor of cell proliferation. Immunohistochemistry and immunoblotting for geminin, however, reveals that the protein is expressed specifically in proliferating lymphocytes and epithelial cells. This pattern is in contrast to the expression of a bona fide cell cycle inhibitor like p21/WAF1 that is specifically expressed in quiescent cells. Geminin is widely expressed in several malignancies and the number of geminin-expressing cells is directly proportional to the cell proliferation index as measured by Ki-67 expression. Therefore, instead of being a suppressor of cell proliferation, geminin expression is positively correlated with cell proliferation. Consistent with this observation, transient overexpression of wild-type geminin in cancer cells in culture did not produce a cell cycle block. A point mutation in the destruction box of geminin, however, results in a protein that is stabilized in G(1) and capable of arresting cells at the G(1)-S transition.     

Interaction of hepatitis B surface antigen (Australia antigen) with membrane vesicles of Pseudomonas aeruginosa.

A lysogenic strain of Pseudomonas aeruginosa was cultured from the dialysis fluid of a patient on chronic hemodialysis treatment whose blood contained hepatitis B surface antigen (HB8Ag). When this bacterium was incubated for 4 to 7 days with serum containing HB8Ag or with purified HB8Ag, a loss of the HB8Ag-specific immunological reactivity was observed. Bacteriophages can be induced from the isolated P. aeruginosa with mitomycin C; the phages, after purification on CsCl gradients, also lyse P. aeruginosa strain 25102 (ATCC). Subsequent to gradient centrifugation of the lysate, a fraction was found with a density around 1.40 g/ml that inactivated HB8Ag after a 4-h incubation at 37 C as determined by counterelectrophoresis and hemagglutination inhibition. The activity was not found in appreciable amounts in other gradient fractions. The electron microscope shows that the active fraction contains envelope vesicles of 45 to 60 nm in diameter. In spite of their loss in HB8Ag activity, the HB8Ag particles (22nm) appeared morphologically intact. These findings suggest that an enzyme(s) is present in the vesicle fraction which inactivates antigenic determinants on HB8Ag particles. Thus, the presence of these bacteria in environments such as feces, dialysis tanks, and contaminated drinking water may prevent the detection of HB8Ag.