细胞技术

The ability to fractionate nucleic acids and to determine which of them has sequences complementary to an array of DNA or RNA molecules is one of the most powerful tools of molecular biology. The Southern blot, named for its inventor, is a method for transferring size-fractionated DNA from a gel matrix ...

A number of cellular processes, including cell proliferation and differentiation, appear to be regulated by the phosphorylation of proteins on tyrosine residues (1,2). The level of tyrosine phosphorylation of intracellular protein substrates is determined by the balance of phos ...

Membrane-constituting phospholipids include glycerol phospholipids such as phos- phatidylcholine and phosphatidylinositol (PI) and sphingolipids. Recently, signal transduction starting from hydrolysis of these phospholipids have attracted attention as regu ...

Intracellular free Ca2+concentration (i) plays a critical role in regulating many diverse cellular functions including cell proliferation and programmed cell death (apoptosis) (1). An elevation in i activates enzymes (phospholipase A2, phospho- lipase D and some isoforms of prot ...

Protein kinases and phosphatases play an important role in a variety of cellular functions such as cell growth, development, and gene expression (1). It is estimated that one-third of the proteins in a typical mammalian cell are phosphorylated and about 200 protein kinases and 100 protein phos ...

Protein kinase C (PKC), a family of phospholipid-dependent serine/threonine kinases, plays a cardinal role in malignancy (1-5). PKC isozymes can be categorized into three groups: Group A or conventional (c) PKC: α, βI, βII, and γ; Group B or novel (n) PKC: δ, ε, η, θ, and �, and Group C or atypical (a) PKC: ζ and λ (ι) (1,3,4). Wher ...

Identification of individual cyclic AMP binding proteins in tumor cytosolic extracts is possibly owing to the ability of 32P-labeled 8-azido cyclic AMP to act as an effective analog of cAMP, to bind specifically to its protein effector sites, and on photo activation to incorporate covalent ...

The techniques presented in this chapter describe the experimental procedure for the identification of the nonrandom DNA fragmentation associated with apoptosis. The major benefits of this method are its ability to detect a low level of DNA fragmentation and its ability to detect large D ...

Physiological or programmed cell death plays an important role during a variety of physiological and pathological processes (1). It is an active form of cell death under tight regulation. Physiological cell death in mammals occurs during embryonic development of organs and tissues; for e ...

The ability of a cell to undergo apoptosis is crucial during development, tissue homeostasis, and in the pathogenesis and treatment of disease (1). To study apoptosis, it is important to be able to detect apoptotic cells reliably. Here we describe a method to detect apoptosis in vitro and in vivo on basis ...

Apoptotic cells were originally recognized by their characteristic morphology. Since then, a series of biochemical changes have been described. However, it has yet to be established whether any of these changes unequivocally identify an apoptotic cell. In any study of apoptosis, it is imp ...

The diphenylamine assay is a very useful tool in measuring apoptosis by determining the percentage of fragmentation of known amounts of DNA into oligosomal-sized fragments. Another advantage of the diphenylamine assay is that apoptotic DNA fragmentation can be analyzed in both adher ...

As a genetically controlled program, apoptosis has important roles in a variety of biological processes. The realization that chemotherapy can also induce apoptosis in some cancer cells both in vitro and in vivo indicates apoptosis may play a very important role in cancer and cancer therapy ( ...

The deregulation of the balance between proliferation and programmed cell death is considered one of the most important features of malignant tumors. The search for new markers, which may reflect the tumor progress and response to various therapy regimens, has recently focused on altera ...

Programmed cell death or apoptosis can be induced by a variety of mechanisms including genotoxic stress (1-3). The initiation of apoptosis involves the activation of a proteolytic cascade reminiscent of the blood-clotting pathway or activation of pancreatic proteases (4). It has been su ...

Cellular heterogeneity of malignant tissues is a well-known phenomenon (1). Intralineal/intraclonal diversity may be explained in part by proposing the concept of a hierarchically ordered, differentiating and self-renewing stem cell system for transformed cell populations ...

Human tumor cell lines have provided valuable model systems to study a wide variety of tumor characteristics including the cell biology, genetics, and chemosensitivity profiles of disease. A large number of ovarian cancer cell lines have now been established and are in widespread use Table 1) ...

Perhaps the most fundamental question that faces the laboratory scientist is, “Which model system should I use to investigate the problem?” Failure to adequately address this issue can compromise even the most meticulous and inspired research program. If this is such a thorny issue, why use mo ...

Since ancient times, cancer has been known to humankind. The ancient Greeks and Romans have left us with writings in which various treatment options are discussed (1). Disease processes and causes were not well understood, however; the humoral pathology established by the ancient Greeks of the ...

Human chorionic gonadotropin (hCG), a glycoprotein hormone composed of two nonidentical α- and β-subunits, is normally produced by trophoblasts. Serum and urine from some patients with nontrophoblastic tumors are found to contain similar immunoactivity to the β-subunit of hCG and th ...