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Cell Theory (cell + theory)
Selected AbstractsArchitectural changes in the developing human brain based on the matrix cell theoryCONGENITAL ANOMALIES, Issue 3 2002Yasuhiro Nakamura ABSTRACT, Architectural changes in the developing human brain are discussed based on the matrix cell theory. Neural stem cells/matrix cells with self-renewing ability and multipotency exist in the developing human brain in vivo. The brain development is divided into three stages and the cell differentiation is time regulated. Immunohistochemical distribution of various markers for brain development is summarized and categorized along with differentiation lineages. Particularly, the existence of glial fibrillary acidic protein is re-evaluated in the developing human brain. The commonly used terms and concepts "radial glial fiber" or "subventricular zone" are also re-evaluated. [source] Theoretical study of wetting behavior of nanoparticles at fluid interfacesAICHE JOURNAL, Issue 3 2009Jianguo Mi Abstract In this work, a theoretical model was developed to describe the wetting behavior of nanoparticles at liquid-vapor interface by the integration of the renormalization group transformation, the cell theory, and the modified fundamental measurement theory with the first-order mean spherical approximation method. The results show that the new model can be used to investigate the global behavior and surface tensions of nanoparticle/fluid systems. Particularly, the nanoparticle's wetting behavior inside critical region was discussed systematically. More important, this work proposed a methodology for calculating line tension and contact angle, showing that line tension has considerable influence on wetting properties for small nanoparticles, whereas it is negligible for large nanoparticles. Therefore, this work provides a general method for studying the wetting behavior of nanoparticles that may find wide applications in the field of chemical engineering. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Lung cancer: Progress in diagnosis, staging and therapyRESPIROLOGY, Issue 1 2010Stephen G. SPIRO ABSTRACT Lung cancer remains one of the greatest medical challenges with nearly 1.5 million new cases worldwide each year and a growing tobacco epidemic in the developing world. This review summarizes briefly the current status in growing areas of clinical research. The value of screening for early disease is not yet established and trials to see if mortality can be improved as a result are in progress. Better and more accurate staging will both streamline investigation and prove cost-effective once ultrasound-guided biopsy and aspiration of mediastinal nodes become universally accepted. This, allied to the new staging classification, will improve selection of cases for surgery, intensive multimodality therapy and for adjuvant treatment postoperatively. Much still needs to be done to refine staging as within a particular stage group, the outcome shows great variation. More information is needed on the genetic make-up in some groups of tumours and not just their size; that is, more biological data on tumour growth patterns are likely to be at least as discriminating. The place of the stem cell theory of tumorigenesis is also explored in this paper. Finally, targeted therapy for advanced non-small-cell lung cancer is highlighted as a development with early promise, but still much clarification is required, before it can be considered as a universal approach in late disease. [source] Are cranial germ cell tumours really tumours of germ cells?NEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 6 2006P. J. Scotting Germ cell tumours of the brain and those that occur in the gonads are believed to share a common origin from germ cell progenitors. This ,germ cell theory' rests upon similar histopathology between these tumours in different locations and the belief that endogenous somatic cells of the brain could not give rise to the range of cell types seen in germ cell tumours. An alternative ,embryonic cell theory' has been proposed for some classes of cranial germ cell tumours, but this still relies on the misplacement of cells in the brain (in this case the earliest embryonic stem cells) during early embryonic development. Recent evidence has demonstrated that neural stem cells of the brain can also give rise to many of the cell types seen in germ cell tumours. These data suggest that endogenous progenitor cells of the brain are a plausible alternative origin for these tumours. This idea is of central importance for studies aiming to elucidate the mechanisms of tumour development. The application of modern molecular analyses to reveal how tumour cells have altered with respect to their cell of origin relies on the certain identification of the cell from which the particular tumour arose. If the identity of this cell is mistaken, then studies to elucidate the mechanisms by which the progenitor cell has been subverted from its normal behaviour will not yield useful information. In addition, it will prove impossible to generate an appropriate animal model in which to study the underlying causes of those tumours. This article makes the case that current assumptions of the origins of cranial germ cell tumours are unreliable. It reviews the evidence in favour of the ,germ cell theory' and argues in favour of a ,brain cell theory' in which endogenous neural progenitor cells of the brain are the likely origin for these tumours. Thus, the case is made that cranial germ cell tumours, like other brain tumours, arise by the transformation of progenitor cells normally resident in the brain. [source] | ||||||||||