Double cell

Interferons [alFN, piFN and ylFN]. Interferons are a family of glycosylated proteins and are cytokines which are produced a few hours after cells have been infected with a virus. Interferons protect cells from viral infections and have antiviral activities at very low concentrations ( 3 x 10 M, less than 50 molecules are apparently sufficient to protect a single cell). Double stranded RNA are very efficient inducers of IFNs. There are three main types of IFNs. The aIFNs are synthesised in lymphocytes and the piFNs are formed in infected fibroblasts. The a and P families are fairly similar consisting of ca 166 to 169 amino acids. Although ylFNs are also small glycosylated proteins (ca 146 amino acids), they are different because they are not synthesised after viral infections but are produced by lymphocytes when stimulated by mitogens (agents that induced cell division). 

Tumor Type Percent of Tumors Approximate Cell Doubling Time Sensitivity to Chemotherapy and Radiotherapy Relative Risk of Metastasis... 

The cell doubling times go from less than 8 h to more than 18 h. Cells are also accumulating in G2. This is coincident with the gradual transition of String from a ubiquitously expressed product to a periodically expressed product. This transition can be largely attributed to regulation of String. 

Edgar We have done this experiment, overexpressing Myc or Ras co-expressed with String. This decreases the cell doubling time and reduces the cell size, but the... 

Derenzini M, Sirri V, Trere D, Ochs RL (1995) The quantity of nucleolar proteins nucleolin and protein B23 is related to cell doubling time in human cancer cells. Lab Invest 73 497—502 Derenzini M, Trere D, Pession A, Govoni M, Sirri V, Chieco P (2000) Nucleolar size indicates the rapidity of cell proliferation in cancer tissues. J Pathol 191 181—186 Derenzini M, Trere D, Pession A, Montanaro L, Sirri V, Ochs RL (1998) Nucleolar function and size in cancer cells. Am J Pathol 152 1291-1297... 

In practice, double-beam instruments are used where the absorption of a reference cell, containing only solvent, is subtracted from the absorption of the sample cell. Double beam instruments also cancel out absorption due to the atmosphere in the optical path as well as the solvent. 

This cultivation method is defined by a limited number of passages or population doublings which must not be exceeded during production. The maximum number of cell doublings, or passage levels, during which the manufacturing process routinely meets the criteria described below, must be stated. 

The earliest detectable human cancers usually have a volume of at least 1 cc and contain 10 (1 billion) cells. This number reflects the result of at least 30 cycles of cell division, or cell doublings, and represents a kineti-cally advanced stage in the tumor s growth. Most patients actually have tumor burdens that are greater than 10 . Since the major limiting factor in chemotherapy is cytotoxicity to normal tissues, only a limited log cell kill can be expected with each individual treatment. 

An overview of commercial ICP mass spectrometers from different companies (quadrupole based ICP-MS with and without collision/reaction cell, double-focusing sector field instrumentation with single and multiple ion collectors, time-of-flight (ToF), ICP-ion trap-MS and non-commercial ICP-Fourier transform ion cyclotron resonance (FTICR) mass spectrometers is given in Figure 5.2. By using ion traps and FTICR mass spectrometers in ICP-MS isobaric interferences of atomic ions... 

Figure 11.4 Elimination of plasmid DNA from the cytoplasm of microinjected cells. Double stranded fluorescein labeled pGL2 plasmid (0.1 pg/ml) was co-injected with TRITC-dextran into the cytosol of HeLa cells and incubated under tissue culture conditions for the indicated time. Cells were fixed and fluorescence micrographs were taken to visualize the distribution of TRITC-dextran (right column) and fluorescein-labeled pGL2 (left column) of the same field, (see Color Plate 11)...

Fig. 12A-E Double-staining for BrdU and neuronal progenitor markers in SGZ. A An example of a BrdU/TUC4 double-stained cell (arrows) (day 9) adjacent to a BrdU+/TUC4 cell. B A BrdU+/Hu+ cell (day 23) with serial scanning at various depths to confirm the colocalization of the two channels. C A cell double-stained for Doublecortin (DCX) and BrdU (day 15) shown with channel separation. D A cell double-stained for /fill-tubulin and BrdU (day 9) extending processes parallel to DGL (arrowheads) is shown with channel separation. E A cell double-stained for PSA-NCAM and BrdU (day 44), extending processes parallel to DGL, is shown with channel separation. Scale bar= 10 pm...

Fig. 14A-E Double-staining for BrdU and mature neuronal markers in DGL. A In control monkey DGL BrdU+ cells (arrows) were distinct from NeuN+ cells. B On day 9 after ischemia BrdU+/NeuN+ cells (arrows) were observed in the innermost layers of granule cells. C BrdU+/NeuN+ cells were seen up to day 79 (arrows). D The cell framed in C is shown in serial sectioning at various depths to confirm the colocalization of the two signals. E An example of cell double-stained for BrdU/GAD (arrows) on day 79. Scale bar = 10 pm...

Stage in the growth cycle when the mass of microbial cells doubles over each of the successive and equal time intervals. The doubling time and, therefore, the growth rate during the entire log phase is thus constant. Volume 1(6). 

Such distribution of the exchange interactions corresponds to a magnetic cell doubled along c axis. The calculations show that the exchange value for the second coordination sphere is rather significant and equals to Jc =0.23 = 0.3 Jc [14], It experimentally revealed that the translation symmetry of the magnetic ground states can be described by two wave vectors either kAF =(o,2/ + 1,1/2) for U-AFM state or kSP=( 2,0,1/2) for SP-state [9]. 

ATP EDTA DMSO BHK CHO HEPES mAbs B Brnax MTT PEG RNA t td WHO X adenosine triphosphate ethylenediaminetetraacetic acid Dim ethylsulf oxide baby hamster kidney cell line Chinese hamster ovary cell line N-(2-hydroxyethyl)piperazine-N -(2-ethanesulphonic acid) monoclonal antibodies specific cell growth rate maximum specific cell growth rate (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide) polyethylene glycol ribonucleic acid cell culture time cell doubling time World Health Organization cell concentration... 

Nucleosome assembly differs from DNA replication. Histone content of a cell doubles during cell doubling, just as the DNA content does. On the leading strand, the pre-existing histone octamers briefly dissociate from the template and then re-bind to the double helix. Newly made nucleosome core particles associate with DNA on either strand. Thus, the overall process of histone doubling is conservative (the histones stay together during replication), in contrast to DNA synthesis, which is semiconservative. 

If the cells do not all have the same generation time then the time taken to double the number of cells (TD the cell doubling time) will be slightly shorter than the generation time (7 ). Alternatively, if not all the cells in the population are growing i.e. the growth fraction is less than 1 (see below) then Tu will be longer than T. 

The time taken for the total number of cells to double (cell doubling time) is therefore not equal to the cell cycle or cell generation time. It is important, therefore, when doing cell cycle analyses to carefully distinguish between T and TD and preferably maintain the growth fraction as high as possible. 

The x-ray diffraction data used by Watson and Crick was obtained from fibers of DNA that were prepared under conditions of high humidity. At lower humidities (<75 percent), a fiber of DNA will shorten. This is a result of a change to the A form, in which the base pairs are not perpendicular to the helix axis they are tilted about 20°, and the pitch is reduced to 2.8 nm with 11 base pairs per turn. While the B-form of the helix is the predominant form in cells, double-stranded RNA and DNA/RNA hybrid molecules generate the A form of the helix. 

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