Milk and dairy products in cancer prevention: focus on bovine lactoferrin

Milk and dairy products constitute an important part of the western style diet. A large number of epidemiological studies have been conducted to determine effects of consumption on cancer development but the data are largely equivocal, presumably reflecting the different included components. It has been proposed that whereas fats in general could promote tumor development, individual milk fats like conjugated linoleic acid could exert inhibitory effects. There is also considerable evidence that calcium in milk products protects against colon cancer, while promoting in the prostate through suppression of circulating levels of 1,25-dihydroxyvitamin D3. Whey protein may also be beneficial, as shown by both animal and human studies, and experimental data have demonstrated that the major component bovine lactoferrin (bLF), inhibits colon carcinogenesis in the post-initiation stage in male F344 rats treated with azoxymethane (AOM) without any overt toxicity. The incidence of adenocarcinomas in the groups receiving 2% and 0.2% bLF were thus 15% and 25%, respectively, in contrast to the 57.5% control value (P<0.01 and P<0.05, respectively). Results in other animal models have provided further indications that bLF might find application as a natural ingredient of milk with potential for chemoprevention of colon and other cancers.     

Molecular cloning and characterization of the promoter region of the inducible nitric oxide synthase gene of the rat

To investigate the mechanism by which inducible nitric oxide synthase (iNOS) within vascular smooth muscle cells (VSMC) is expressed following exposure to proinflammatory cytokines, we cloned the promoter region of the rat iNOS gene by a single specific primer PCR cloning strategy. The 5;-flanking region of the rat iNOS gene contains interferon-gamma (IFN-gamma)- and tumor necrosis factor-alpha (TNF-alpha)-responsive elements and an NF-kappaB-binding consensus sequences. The position and alignment of these consensus sequences are distinct from those in the mouse iNOS and human iNOS genes. It was shown that some nuclear factor(s) which bound specifically to the fragment of the rat iNOS gene containing several consensus sequences were produced after VSMC were treated with interleukin 1 (IL-1) and IFN-gamma.     

High endemicity of Metagonimus yokogawai infection among residents of Samchok-shi, Kangwon-do

A small-scale epidemiological survey was undertaken during 1997-1998 on the residents along the Osib-chon (Stream), Samchok-shi (City), Kangwon-do (Province), to evaluate the status of Metagonimus yokogawai infection. A total of 165 fecal samples was collected and examined by cellophane thick smear and formalin-ether sedimentation techniques. The egg positive rate of M. yokogawai was 29.7%, showing a remarkable difference between males (46.6%) and females (16.3%). To obtain the adult flukes of M. yokogawai, 11 egg positive persons were treated with praziquantel and purged with magnesium sulfate. A total of 242,119 adult flukes (average 22,010 per person, 367-119,650 in range) was collected from diarrheic stools, all of which were identified as M. yokogawai. The results show that M. yokogawai is still highly endemic in this area.     

Transesterification of phosphatidylcholine with eicosapentaenoic acid ethyl ester using phospholipase A2 in organic solvent

Phospholipase A₂-catalysed transesterification of phosphatidylcholine (PC, 99%) with eicosapentaenoic acid ethyl ester (EPAEE, 95%) was carried out in organic solvent. The maximum yield was 14.3% (w/w). The optimum reaction condition was 50°C, 48 h, initial water activity 0.25 and molar ratio of PC to EPAEE 1:10 in 5 ml toluene.     

The Superoxide Synthases of Rose Cells : Comparison of Assays

In an effort to identify the enzymatic mechanism responsible for the synthesis of reactive oxygen species produced during the hypersensitive response, preparations of rose (Rosa damascena) cell plasma membranes, partially solubilized plasma membrane protein, and cytosol were assayed for the NADH- and NADPH-dependent synthesis of superoxide using assays for the reduction of cytochrome c (Cyt c), assays for the reduction of nitroblue tetrazolium, and assays for the chemiluminescence of N,N′-dimethyl-9,9′-biacridium dinitrate (lucigenin). Each assay ascribed the highest activity to a different preparation: the Cyt c assay to cytosol, the nitroblue tetrazolium assay to plasma membrane, and the lucigenin assay to the partially solubilized plasma membrane protein (with NADH). This suggests that no two assays measure the same set of enzymes and that none of the assays is suitable for comparisons of superoxide synthesis among different cell fractions. With the plasma membrane preparation, the presence of large amounts of superoxide-dismutase-insensitive Cyt c reductase confounded attempts to use Cyt c to measure superoxide synthesis. With the partially solubilized membrane protein, direct reduction of lucigenin probably contributed to the chemiluminescence. Superoxide synthesis detected with lucigenin should be confirmed by superoxide-dismutase-sensitive Cyt c reduction.     

A molecular systematic study ofCathaya, a relic genus of thePinaceae in China

The systematic position ofCathaya, a relic genus of thePinaceae, was discussed based on therbcL gene sequence. The sequence data were analysed with PAUP and MEGA programs. The great genetic distance value betweenCathaya and any other genus of thePinaceae showed thatCathaya was a distinct and isolated genus. The most parsimonious Fitch tree and neighbor-joining tree showed thatCathaya was distantly related to the clade comprisingAbies, Keteleeria, Pseudolarix andTsuga, and a sister group relationship betweenCathaya andPinus was weakly supported.Pseudotsuga is closely related toLarix. In theAbies-Keteleeria-Pseudolarix-Tsuga clade,Abies has a close relationship toKeteleeria whilePseudolarix is relatively closely related toTsuga.     

芥蓝下胚轴离体培养及高频率植株的再生

三个芥蓝品种下胚轴离体植株再生的条件的研究结果表明：下胚轴切口处可直接诱导出芽,诱导“早花尖叶芥蓝”、“中花尖叶芥蓝”和“迟花尖叶芥蓝”直接出芽的最佳激素组合分别为2．0mgL-1BA,0．3mgL-1NAA＋2．0mgL-1BA,0．5mgL-1NAA＋2．0mgL-1BA,其相应的芽发生频率分别为84．6％,86．7％,93．3％。诱导芽发生的最适蔗糖浓度是1％。培养基中加入4．0mgL-1AgNO3和500mgL-1MES可显著提高芽再生频率。再生芽在MS附加0．1mgL-1NAA的培养基上诱导生根形成完整植株。离体再生苗与种子萌发实生苗田间生长外形差别不大,但长势稍慢。     

冻干腮腺炎活疫苗细胞培养生产工艺研究

报告了冻干腮腺炎活疫苗细胞培养生产工艺研究结果,通过对鸡胚疫苗株的适应培养及对细胞培养生产工艺的试验优化,建立了连续细胞培养多次收获疫苗生产工艺并制备出了冻干细胞培养腮腺炎活疫苗制剂。本生产工艺切实可行,生产成本低、投入产出率高,所用原材料规范、质量易于控制,具有明显的技术优势。生产的冻干疫苗制剂质量稳定可靠,符合中国生物制品规程要求,有利于预防腮腺炎的规模化推广使用     

On-line sample preparation of paraquat in human serum samples using high-performance liquid chromatography with column switching

A new ion-pair high-performance liquid chromatographic method with column-switching has been developed for the determination of paraquat in human serum samples. The diluted serum sample was injected onto a precolumn packed with LiChroprep RP-8 (25-40 μm) and polar serum components were washed out by 3% acetonitrile in 0.05 M phosphate buffer (pH 2.0) containing 5 mM sodium octanesulfonate. After valve switching to inject position, concentrated compounds were eluted in the back-flush mode and separated on an Inertsil ODS-2 column with 17% acetonitrile in 0.05 M phosphate buffer (pH 2.0) containing 10 mM sodium octanesulfonate. The total analysis time per sample was about 30 min and mean recovery was 98.5±2.8% with a linear range of 0.1–100 μg/ml. This method has been successfully applied to serum samples from incidents by paraquat poisoning.