小鼠早期胚胎几种不同培养方法的比较

目的探讨小鼠胚胎体外发育中的最佳培养方案。方法将从超排的ICR雌鼠输卵管内收集的1-细胞放入无糖CZB中培养,分别于2-细胞、4-细胞、桑椹胚阶段更换入含3.0 mmol/L葡萄糖(最适浓度)的CZB中,以及胚胎培养全程均在含糖CZB中更换1次培养液、胚胎培养全程均在含糖CZB中不更换培养液,对照组胚胎培养全程均在无糖CZB中,观察记录胚胎的发育情况。结果2-细胞、4-细胞阶段换入含糖CZB中的序贯培养及培养全程在含糖CZB中单一培养,囊胚率均高于对照组(P<0.05);桑椹胚阶段换入含糖CZB中的序贯培养,囊胚率与对照组差异无统计学意义(P>0.05);2-细胞、4-细胞阶段换入含糖CZB中的序贯培养与全程在含糖CZB中的两步法单一培养及一步法单一培养,囊胚率分别为46.5%、38.4%、41.7%、56.6%,其差异无统计学意义(P>0.05)。结论在小鼠早期胚胎体外发育中,2-细胞至桑椹胚前对葡萄糖存在依赖性;尽管序贯培养是有效的,但并不一定优于一步单一培养。

培基介导的辐射旁效应及机理初探

采用ICR小鼠,转移受照射细胞的条件培养液来培养未受照射细胞,检测YAC?I(小鼠T淋巴瘤)细胞对小鼠自然杀伤(NK)细胞的敏感性变化,测定小鼠脾细胞增殖能力,观察自由基清除剂二甲基亚砜(Dimethylsulfoxide,DMSO)照射前处理细胞的影响。初步研究了电离辐射旁效应(Bystandereffect,BE)及其可能的机理。结果显示,条件培养液培养的Yac?I细胞对NK细胞的敏感性明显升高。用条件培养液培养的小鼠脾细胞的增殖能力也明显受到抑制,提示辐射旁效应的存在,观察到DMSO对旁效应有一定的抑制作用,说明活性氧(Reactiveoxygenspecies,ROS)等自由基对旁效应有一定贡献。然而在淋巴细胞增殖实验ICM+1%DMSO组的数据显示DMSO对旁效应的抑制作用非常有限,表明除自由基外必定存在其他因素介导旁效应的发生。

用培养基介导法研究辐射旁效应及其机理

目的通过受照射的细胞培养液培养靶细胞,并用二甲基亚砜(DMSO)对靶细胞预处理,检测其对自然杀伤(NK)细胞活性的影响,研究旁效应是否存在及其产生机理。方法以健康雄性ICR小鼠脾NK细胞活性检测经过不同剂量照射的细胞培养液对小鼠淋巴瘤YacⅠ细胞的损伤程度,同时观察DMSO对该细胞的保护作用,即对旁效应的抑制作用。结果应用不同剂量60Coγ射线照射的细胞培养液来培养YacⅠ细胞,引发该细胞不同程度的损伤,表现在YacⅠ细胞对小鼠脾NK细胞的敏感性增强(P<0.01);DMSO预处理细胞对旁效应有一定的抑制作用,特别在0.25和0.5Gy组,对细胞的保护作用明显。结论60Coγ射线照射能诱发YacⅠ细胞的培养液介导的旁效应。活性氧(ROS)是诱发辐射旁效应的因素之一,清除ROS可部分抑制辐射旁效应。

辐射诱发肿瘤细胞旁效应的免疫学实验研究

目的　研究用自然杀伤 (NK)细胞活性的变化检测肿瘤细胞Yac Ⅰ在6 0 Coγ射线照射后是否存在旁观者效应 (旁效应 ) ,以及其旁效应剂量学和时间效应特征。方法　以健康ICR小鼠脾NK细胞活性为生物终点 ,检测NK细胞对不同条件培养肿瘤细胞Yac Ⅰ的活性 ,用培养基介导法观察旁效应 ,同时 ,培养不同时间观察其时间规律。结果　每个剂量组NK细胞活性的均值与对照细胞NK细胞活性均值差异有显著性 (P <0 0 5 )。照射后分别培养 0和 2 4h ,各剂量组间的NK细胞活性均值差异无显著性。结论　6 0 Coγ射线照射能诱发肿瘤细胞Yac Ⅰ的旁效应。旁效应在低剂量时较为明显。

An introduction to the trapping of clusters with ion traps and electrostatic storage devices

This paper presents an introduction to the application of ion traps and storage devices for cluster physics. Some experiments involving cluster ions in trapping devices such as Penning traps, Paul traps, quadrupole or multipole linear traps are briefly discussed. Electrostatic ion storage rings and traps which allow for the storage of fast ion beams without mass limitation are presented as well. We also report on the recently developed mini-ring, a compact electrostatic ion storage ring for cluster, molecular and biomolecular ion studies.

Structural characterization and identification of dibenzocyclooctadiene lignans in Fructus Schisandrae using electrospray ionization ion trap multiple-stage tandem mass spectrometry and electrospray ionization Fourier transform ion cyclotron resonance multiple-stage tandem mass spectrometry

The electrospray ionization ion trap multiple-stage tandem mass spectrometry (ESI-MSn) and electrospray ionization Fourier transform ion cyclotron resonance multiple-stage tandem mass spectrometry (ESI-FT-ICR-MSn) have been applied successfully to the direct investigation of a number of dibenzocyclooctadiene lignan constituents from the methanol extracts of the Fructus Schisandrae in the positive ion mode. The detailed structural characterization of the same skeleton and different peripheral substituents had been studied and the precise elemental compositions of ions at high mass resolution had been obtained. So the fragmentation mechanisms could be clarified.

山楂叶总黄酮中α-葡萄糖苷酶抑制剂的超滤质谱筛选研究

In vitro α-glycosidase inhibition assays and Ultrafiltration LC-DAD-ESI-MSn were combined to screening α-glucosidase inhibitors from hawthorn leaves flavonoids extract. As a result, hawthorn leaves flavonoids extract showed strong α-glucosidase inhibitory activity, four compounds presented α-glucosidase inhibitory effects were observed and identified by LC-DAD-MSn, and further confirmed by high resolution SORI-CID FT ICR MS data.

High resolution mass spectrometric alveolar proteomics: Identification of surfactant protein SP-A and SP-D modifications in proteinosis and cystic fibrosis patients

In the present study, one- and two-dimensional gel electrophoresis combined with high resolution Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) have been applied as powerful approaches for the proteome analysis of surfactant proteins SP-A and SP-D, including identification of structurally modified and truncation forms, in bronchoalveolar lavage fluid from patients with cystic fibrosis, chronic bronchitis and pulmonary alveolar proteinosis. Highly sensitive micro preparation techniques were developed for matrix-assisted laser desorption/ionization (MALDI) FT-ICR MS analysis which provided the identification of surfactant proteins at very low levels. Owing to the high resolution, FT-ICR MS was found to provide substantial advantages for the structural identification of surfactant proteins from complex biological matrices with high mass determination accuracy. Several protein bands corresponding to SP-A and SP-D were identified by MALDI-FT-ICR MS after electrophoretic separation by one- and two-dimensional gel electrophoresis, and provided the identification of structural modifications (hydroxy-proline) and degradation products.

Analysis of strychnos alkaloids using electrospray ionization Fourier transform ion cyclotron resonance multi-stage tandem mass spectrometry

The fragmentations of four strychnos alkaloids have been investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) in the positive ion mode. Experiments using multi-stage tandem mass spectrometry (ESI-FT-ICR-MSn) allowed us to obtain precise elemental compositions of product ions at high mass resolution. The experimental data demonstrated that the nitrogen bridge and the coordinated oxygen atom on the nitrogen bridge in the alkaloid compounds were the active sites in the MS2 fragmentations. The loss of CH3 or the OCH3 group in those alkaloids, which have an OCH3 substituent, was the dominant fragmentation mode in the MS3 fragmentations. Logical fragmentation schemes for strychnos alkaloids have been proposed and these should be useful for the identification of these compounds.

Polysaccharides from Ulva pertusa (Chlorophyta) and preliminary studies on their antihyperlipidemia activity

Polysaccharides from Ulva pertusa were isolated and prepared by extraction in hot water and precipitation by ethanol. The water-soluble polysaccharides were chemically well defined, containing 47.0% total carbohydrate, 23.2% uronic acids, 17.1% sulfate groups, 1.0% N and 29.9% ash. Gas chromatography analysis demonstrated that the neutral sugars were mainly composed of rhamnose, xylose and glucose and smaller amounts of mannose, galactose and arabinose. The FTIR and C-13-NMR spectra indicated that basic repeating units of the polysaccharides were (beta-D-GlcpA-(1->4)-alpha-L-Rhap 3S) and (alpha-L-IdopA-(1->4)-alpha-L-Rhap 3S). Fifty ICR mice were used to study the effect of water-soluble polysaccharides from Ulva pertusa on the level of plasma lipids, with inositol niacinate as positive control. The results indicated that the polysaccharides significantly lowered the contents of plasma total cholesterol, low-density lipoprotein cholesterol, triglyceride and markedly increased the contents of serum high-density lipoprotein cholesterol, compared with the hyperlipidemia control group (p<0.01). Moreover, administration of polysaccharides significantly decreased the atherogenic index. The present results suggest that the polysaccharides from Ulva pertusa have great potential for preventing ischemic cardiovascular and cerebrovascular diseases.

Chemical compositions of four B-type supergiants in the SMC wing

High-resolution UCLES/AAT spectra of four B-type supergiants in the SMC South East Wing have been analysed using non-LTE model atmosphere techniques to determine their atmospheric parameters and chemical compositions. The principle aim of this analysis was to determine whether the very low metal abundances (-1.1 dex compared with Galactic value) previously found in the Magellanic Inter Cloud region (ICR) were also present in the SMC Wing. The chemical compositions of the four targets are similar to those found in other SMC objects and appear to be incompatible with those deduced previously for the ICR. Given the close proximity of the Wing to the ICR, this is difficult to understand and some possible explanations are briefly discussed.

Participation of adult mouse bone marrow cells in reconstitution of skin

Results of recent studies have indicated that bone marrow cells can differentiate into various cells of ectodermal, mesodermal, and endodermal origins when transplanted into the body. However, the problems associated with those experiments such as the long latent period, rareness of the event, and difficulty in controlling the processes have hampered detailed mechanistic studies. In the present study, we examined the potency of mouse bone marrow cells to differentiate into cells comprising skin tissues using a skin reconstitution assay. Bone marrow cells from adult green fluorescent protein (GFP)-transgenic mice were transplanted in a mixture of embryonic mouse skin cells (17.5 days post-coitus) onto skin defects made on the backs of nude mice. Within 3 weeks, fully differentiated skin with hair was reconstituted. GFP-positive cells were found in the epidermis, hair follicles, sebaceous glands, and dermis. The localization and morphology of the cells, results of immunohistochemistry, and results of specific staining confirmed that the bone marrow cells had differentiated into epidermal keratinocytes, sebaceous gland cells, follicular epithelial cells, dendritic cells, and endothelial cells under the present conditions. These results indicate that this system is suitable for molecular and cellular mechanistic studies on differentiation of stem cells to various epidermal and dermal cells.

Forebrain ependymal cells are Notch-dependent and generate neuroblasts and astrocytes after stroke

Neurons are continuously generated from stem cells in discrete regions in the adult mammalian brain. We found that ependymal cells lining the lateral ventricles were quiescent and did not contribute to adult neurogenesis under normal conditions in mice but instead gave rise to neuroblasts and astrocytes in response to stroke. Ependymal cell quiescence was actively maintained by canonical Notch signaling. Inhibition of this pathway in uninjured animals allowed ependymal cells to enter the cell cycle and produce olfactory bulb neurons, whereas forced Notch signaling was sufficient to block the ependymal cell response to stroke. Ependymal cells were depleted by stroke and failed to self-renew sufficiently to maintain their own population. Thus, although ependymal cells act as primary cells in the neural lineage to produce neurons and glial cells after stroke, they do not fulfill defining criteria for stem cells under these conditions and instead serve as a reservoir that is recruited by injury.

Avaliação do efeito de metais pesados na fertilidade do ratinho

A infertilidade é um problema actual que afecta cerca de 8 a 12% dos casais em idade fértil, sendo 50% dos casos atribuídos ao factor masculino. A exposição ocupacional e/ou ambiental a metais pesados representa uma das suas principais causas. O chumbo, o cádmio e o crómio são metais com elevada utilização industrial e muito persistentes no ambiente, sendo motivo de grande preocupação devido aos seus efeitos na saúde reprodutiva dos trabalhadores e da população em geral. Neste trabalho estudaram-se os efeitos do cloreto de chumbo (PbCl2), cloreto de cádmio (CdCl2) e cromato de potássio (K2CrO4) na fertilidade, usando como modelo ratinhos machos ICR-CD1. Os ratinhos foram injectados subcutaneamente com 74 e 100 mg de PbCl2/kg pc ou com 5 e 10 mg de K2CrO4/kg pc, respectivamente, durante 4 dias consecutivos ou com 1, 2 e 3 mg de CdCl2/kg pc numa única injecção. Nos ensaios com PbCl2 e K2CrO4 os animais foram sacrificados 5 e 35 dias após o início da exposição, enquanto que nos ensaios com CdCl2 os animais foram sacrificados após 24 horas e 35 dias. O cloreto de chumbo não alterou a histologia do testículo nem do epidídimo, mas induziu um aumento da percentagem de células em fase S no testículo. O cloreto de chumbo alterou também alguns parâmetros dos espermatozóides, tais como a motilidade, morfologia e integridade do acrossoma. Contudo, não foram observados efeitos na integridade do DNA ou na estrutura da cromatina. O cloreto de cádmio induziu lesões severas e não reversíveis nos testículos que, após 35 dias, reverteram em necrose testicular. O cloreto de cádmio alterou ainda as subpopulações de células testiculares após 24 horas e induziu IMS no testículo após 35 dias. Em consequência das lesões no testículo, a densidade espermática foi severamente afectada após 35 dias. A exposição ao cloreto de cádmio afectou também a morfologia, a motilidade e a integridade acrossómica nos espermatozóides. O cloreto de cádmio induziu ainda fragmentação do DNA nestas células após 35 dias. O cromato de potássio alterou a morfologia dos espermatozóides e a integridade do acrossoma, sobretudo nos animais sacrificados após 35 dias. Verificou-se ainda uma redução da motilidade dos espermatozóides. Não foram detectados efeitos genotóxicos nos espermatozóides, devido à acção do K2CrO4 nas doses testadas. Dos parâmetros avaliados neste trabalho, destacam-se duas novas abordagens, nomeadamente o programa informático Snakes e a análise do conteúdo em DNA de células de testículo, a partir de material incluído em parafina. O Snakes permitiu fazer medições rigorosas do diâmetro dos tubos seminíferos, enquanto que a fixação de amostras de testículo de ratinhos em formol tamponado e inclusão em parafina resultou numa boa preservação do DNA, possibilitando assim a quantificação das subpopulações de células testiculares por citometria de fluxo. Os resultados obtidos para os diferentes parâmetros testados indicam que a motilidade dos espermatozóides e a integridade do acrossoma sejam parâmetros sensíveis à toxicidade de metais. O acrossoma aparenta ser um dos principais alvos da toxicidade dos metais e cuja reacção acrossómica prematura pode reduzir a capacidade do espermatozóide para fertilizar o oócito. Assim, este trabalho representa uma contribuição para uma melhor compreensão dos efeitos do chumbo, cádmio e crómio na fertilidade masculina.

Identification of Streptococcus gallolyticus subsp. macedonicus as the etiological agent in a case of culture-negative multivalve infective endocarditis by 16S rDNA PCR analysis of resected valvular tissue

Today, PCR using broad-range primers is being used increasingly to detect pathogens from resected heart valves. Herein is described the first case of multivalve infective endocarditis where 16S rDNA PCR was used to detect a single pathogen from two affected valves in a 61-year-old man. Triple heart valve replacement was required despite six weeks of appropriate antimicrobial therapy. The organism was confirmed as Streptococcus gallolyticus subsp. macedonicus, a member of the 'S. equinus/S. bovis' complex. To date, only one report has been made of human infection due to this organism. This may be due to the limited resolution of the routine diagnostic methods used and/or as a consequence of the complex nomenclature associated with this group of organisms.