首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Currently, the mainly used characteristics to predict outcome or treatment response in patients with breast cancer are tumor size, N-status, histological grade and receptor status (ER/PgR). However, these conventional clinico-pathological characteristics are of limited value. More accurate determinators are needed to select patients who are most likely to benefit from treatment in terms of prognosis as well as treatment response. Proliferation and apoptosis are assumed to play a key role in tumor progression as well as response to treatment. Currently, an increasing number of molecular factors controlling apoptosis as well as proliferation is known. The clinical relevance of apoptotic tumor markers in the treatment strategy of patients with breast cancer is the subject of this review. In addition, potential future developments are discussed.  相似文献   

2.
J.E. Purkyn? was the first to discover, by achromatic microscopy of stained and fixed as well as of fresh material, that animal tissues in general, and those of the central nervous system in particular, are made up of cells, as are those of plants. His discoveries laid the foundations of modern research on the ultrastructure and biophysies of the cerebellar neurons which bear his name, as well as on other types of neurons, in vitro as well as in vivo.  相似文献   

3.
The mode of action of the different thrombolytic substances which are presently available is described. Alterations of the clotting mechanism which are to be expected during thrombolytic therapy as well as possible side effects of the fibrinolytic drugs are listed. Laboratory tests necessary for the control of thrombolytic therapy as well as the different test methods and their normal ranges are mentioned in detail.  相似文献   

4.
Members of the RNaseA family are present in various tissues and secretions but their function is not well understood. Some of the RNases are proposed to participate in host defence. RNase4 and RNase5 are present in cows' milk and have antimicrobial activity. However, their presence in many tissues and secretions has not been characterised. We hypothesised that these two RNases are present in a range of tissues and secretions where they could contribute to host defence. We therefore, determined the relative abundance of RNase4 and RNase5 mRNA as well as protein levels in a range of host defence related and other tissues as well as a range of secretions in cattle, using real time PCR and western blotting. The two RNases were found to be expressed in liver, lung, pancreas, mammary gland, placenta, endometrium, small intestine, seminal vesicle, salivary gland, kidney, spleen, lymph node, skin as well as testes. Corresponding proteins were also detected in many of the above tissues, as well as in seminal fluid, mammary secretions and saliva. This study provides evidence for the presence of RNase4 and RNase5 in a range of tissues and secretions, as well as some major organs in cattle. The data are consistent with the idea that these proteins could contribute to host defence in these locations. This work contributes to growing body of data suggesting that these proteins contribute to the physiology of the organism in a more complex way than acting merely as digestive enzymes.  相似文献   

5.
Optical and spectroscopic methods for biofilmexamination and monitoring are reviewed.Biofilm examination techniques includemicroscopic methods, coupled with imageanalysis and with oligonucleotide ribosomal RNAprobing methods (fluorescence in situhybridization). Microscopic examinationtechniques are especially advantageous inextracting biofilm structural and architecturalparameters, as well as structure-functionrelationships of the biofilm microbialpopulation. Spectroscopic techniques are ableto elicit biofilm chemical and metabolicpatterns, as well as biofilm activity. They areof outstanding importance for on-line,non-invasive biofilm monitoring, especiallywhen coupled with chemometric algorithms forspectra calibration and pattern recognition.The paper emphasises the importance of thecombination of novel and established analyticaltechniques, as well as their integration withpowerful computational methods for theautomation of biofilm monitoring.  相似文献   

6.
Static and dynamic light scattering are discussed as particularly useful tools for studying various aspects of protein crystal growth. Specific applications for prenucleation assays as well as for monitoring postnucleation growth processes are presented. Protein-protein interactions determined by light scattering, which serve as a predictor for favorable crystallization conditions as well as for protein solubility behavior, are detailed. Several precautions regarding the practical aspects of light scattering and interpretation of data are also discussed.  相似文献   

7.
Natural fragmentation of peptide and other chemical structures is well known. They are a significant object of biochemical investigations. In this connection, the bases and determination are given for the notion of the “fragmentome” as a set of all fragments of a single substance, as well as for global fragmentome of all chemical components of living organisms. It is described how protein-peptide fragments are formed in nature, what experimental and theoretical methods are used for their investigation, as well as mathematical characteristics of fragmentomes. Individual fragmentomes of all subunits and of complete casein fragmentome are considered in detail. Structural and functional variety of its possible fragments was revealed by computer analysis. Formation in an organism of an exogenous-endogenous pool of oligopeptides and correlation of these data with concepts of structure-functional continuum of regulatory molecules is shown on an example of food protein fragments. Possible practical importance of the use of natural fragments in dietology, therapy, as well as in sanitary hygiene and cosmetics is noted.  相似文献   

8.
The complete 18S (SSU) rRNA as well partial 28S (LSU) rRNA and partial mitochondrial COI sequences have been used to reconstruct the phylogenetic relationships within Opisthobranchia with special focus on the pelagic orders Thecosomata and Gymnosomata. Maximum parsimony, maximum likelihood, distance as well as Bayesian analysis of a combined dataset of the three genes reveals that Thecosomata and Gymnosomata are sister groups and together are closely related to Anaspidea. Possible sister taxon to Thecosomata, Gymnosomata and Anaspidea is Cephalaspidea s. str . Analysis of a taxon-extended dataset of partial 28S sequences supported a basal position of Limacina within Euthecosomata. Within Cavolinidae, Creseis is basal to the other taxa. Other phylogenetic implications from the present results are also discussed. Investigation of the morphology and histology of Thecosomata and Gymnosomata as well as several other opisthobranch taxa helped to identify autapomorphies for Thecosomata and Gymnosomata as well as apomorphies for the clades including these taxa.  相似文献   

9.
A new synthesis of N-maleoyl-omega-amino acids, their use for the introduction of the maleimido group into peptide factors as well as the stability of this group under standard conditions of conventional peptide synthesis are described. The relatively high stability of N-maleoyl-peptide derivatives in aqueous solutions at neutral or slightly acidic pH values as well as the fast addition of thiol compounds to the maleimido group indicate that these peptide derivatives are well suited for the preparation of tracers of peptide factors and of peptide-protein conjugates.  相似文献   

10.
The flow characteristics of a gravity-driven dense granular flow in a granular bed with a contracted drainage orifice are studied by using discrete element method and quantitative analysis. Three values of discharging rates, ranging from fast to slow dense flows, are investigated. Time variations and derivatives of mean forces and velocities, as well as their respective correlations, are analyzed to quantitatively depict the characteristics of granular flow as well as flow regime categorization. The auto-correlation functions, as well as their Fourier spectrums, are utilized to characterize the differences between the mechanisms of slow and fast granular flows. Finally, it is suggested that the flow regimes of slow and fast flows can be characterized by the kinetic and kinematic flow properties of particles.  相似文献   

11.
Neovascularisation is critical in several malignant and inflammatory conditions, as well as in the course of eye disorders. During new vessel formation, endothelial cell functions, such as proliferation and sprouting are very important and are regulated by a variety of growth factors. The DNA damage response machinery as well as factors regulating histone modifications, such as histone deacetylases, regulate cell fate as well as gene expression. Recent evidence has pointed to potential interactions among BRCA1, H2AX and SIRT1 in these intracellular pathways and neovascularisation, which will be reviewed here.  相似文献   

12.
Structures in focus--filopodia   总被引:4,自引:0,他引:4  
Filopodia are thin cell surface extensions filled with tight parallel bundles of actin filaments. They are highly dynamic structures which rapidly extend and retract as well as sweep up and down and from side to side, and can be found at the leading edge of many types of motile cells such as fibroblasts and keratinocytes, as well as the growth cone tips of migrating axons. Cells appear to use filopodia to explore the extracellular matrix (ECM) and surfaces of other cells, identifying appropriate targets for adhesion or in the case of a migrating growth cone, for sensing guidance cues that enable the axon to navigate to it's appropriate target. As well as this sensory role, filopodia have also recently been shown to play an important mechanical role in epithelial adhesion, and are likely to be key players in developmental processes that require migrating epithelial sheets to zipper and fuse to one another. Their dynamic properties as well as their tendency to be damaged or lost after fixation mean they are best analysed using live imaging techniques. As this field improves, the number of tissues in which filopodia are seen to be playing key roles is fast increasing.  相似文献   

13.
Stevioside   总被引:14,自引:0,他引:14  
Geuns JM 《Phytochemistry》2003,64(5):913-921
Stevioside is a natural sweetener extracted from leaves of Stevia rebaudiana (Bertoni) Bertoni. The literature about Stevia, the occurrence of its sweeteners, their biosynthetic pathway and toxicological aspects are discussed. Injection experiments or perfusion experiments of organs are considered as not relevant for the use of Stevia or stevioside as food, and therefore these studies are not included in this review. The metabolism of stevioside is discussed in relation with the possible formation of steviol. Different mutagenicity studies as well as studies on carcinogenicity are discussed. Acute and subacute toxicity studies revealed a very low toxicity of Stevia and stevioside. Fertility and teratogenicity studies are discussed as well as the effects on the bio-availability of other nutrients in the diet. The conclusion is that Stevia and stevioside are safe when used as a sweetener. It is suited for both diabetics, and PKU patients, as well as for obese persons intending to lose weight by avoiding sugar supplements in the diet. No allergic reactions to it seem to exist.  相似文献   

14.
The paper summarize the main data relevant to the obtention of contraceptive vaccines based on spermatozoa as well as zona pellucida antigens. The development of novel forms of contraception is one way in which this global population problems can be tackled. The sperm as well as the oocyte antigens are studied as possible contraceptive vaccine candidates are the subject of this review.  相似文献   

15.
Cities large and small have a treasure trove of building stones both local as well as imported from various regions of the country as well as foreign sources. Many of them contain fossils which are easily available for teachers to utilize for class field trips. For some areas guidebooks exist which are listed in the attached appendix. Even for localities where no guidebook exists these published guides can be helpful especially if they are illustrated. Field trips are a useful learning tool and teachers are encouraged to create various lesson plans utilizing this generally unrecognized resource.  相似文献   

16.
Copepods are common components of the groundwater fauna, and greatly increase the diversity of groundwater communities. With more than 900 species/subspecies known from continental groundwaters, stygobiont copepods inhabit all kinds of aquifers (karstic, fissured, porous), as well as surface/subsurface ecotones (land/water and water/water). The polyhedral and varied structure of the stygohabitats is reflected in the surprising mixture of functional morphologies and habitat exploitations experienced by groundwater copepods. Morphological adaptations and specializations are discussed, as well as the chronology of their appearance in the evolutionary history of several taxa. Diversity patterns of copepod assemblages in groundwater are examined under both structural and functional profiles, as well as across a range of scales. Structure and function operate in an interactive, sometimes hierarchical ways, as well as scales. On the ecological scale, local heterogeneity and patchiness in geomorphic and hydrologic characteristics, as well as biotic interactions, are to be considered causal factors affecting the diversity patterns over a range of spatial and temporal scales. On the evolutionary scale, it is widely accepted that stygobiont copepods evolved from ancestors living in marine, freshwater and semiterrestrial environments. They gained access to the groundwater through major highways represented by the interstitial and the crevicular/karstic corridors. `Phylogenetic diversity' in groundwater copepod taxocoenoses is viewed as a heterogeneous assemblage of species belonging to different phylogenetic lineages, which entered groundwater at different times and by different ways.  相似文献   

17.
The review highlights the history of genetic toxicology as a distinct research area, as well as the issues of genetic toxicology and development of its methodology. The strategies and testing patterns of genotoxic compounds are discussed with the purpose of identifying potential human carcinogens, as well as compounds capable of inducing heritable mutations in humans. The main achievements of genetic toxicology in the 20th century are summarized and the challenges of the 21st century are discussed.  相似文献   

18.
Living-matter precursors are obtained by the action of the high-frequency electrical discharges on a methane-ammonia-water mixture. Some purine and pyrimidine bases as well as nucleosides are detected and estimated quantitatively by column chromatography, one- and two-dimensional paper chromatography, paper chromatography with standard addition, colour tests as well as by optical density measurement within the UV region.  相似文献   

19.
Living-matter precursors are obtained by the action of the high-frequency electrical discharges on a methane-ammonia-water mixture. Some purine and pyrimidine bases as well as nucleosides are detected and estimated quantitatively by column chromatography, one- and two-dimensional paper chromatography, paper chromatography with standard addition, colour tests as well as by optical density measurement within the UV region.  相似文献   

20.
随着纳米技术的发展,纳米颗粒因具有较高的转染效率、良好的靶向性及有效的基因保护作用而被用作基因载体。简要介绍了磁性纳米颗粒、硅纳米颗粒及阳离子多聚物颗粒等的研究进展。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号