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311.
Determination of the doubling time for a population of cells can involve tedious calculations. We have developed computer software for MS-DOS microcomputers to expedite the analysis of tumor cell growth in vitro and in vivo. This program, DOUBLE-TIME, assists in the collection of cell numbers into a database and calculates the doubling time for a population of cells from the plot of cell growth over time. For experiments where tumor mass is measured in vivo, the software collects measurements of tumor size, calculates tumor volume (mass), generates growth curves for tumor volume change over time, and determines the doubling time of the tumor and the mean for multiple tumors. DOUBLE-TIME plots both total and viable cell numbers over time, calculates standard error of the doubling time, and the doubling time for a selected portion of a growth curve. This software also automates the cell counting process with a software-generated cell counter that allows cell counts to be tallied directly into the computer via a mouse. 相似文献
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EA Kubareva NL Vasilenko OV Vorobjeva EM Volkov TS Oretskaya GA Korshunova GA Nevinsky 《Canadian Metallurgical Quarterly》1998,46(3):597-606
Interaction of different oligodeoxyribonucleotides (oligos), their analogs and oligonucleopeptide with uracil-DNA glycosylase (UDG) from human placenta was investigated. It is shown that there is no considerable contribution of heterocyclic bases of DNA to UDG-substrate binding but the UDG interaction with some DNA phosphate groups is necessary for enzyme-substrate recognition. However the phosphate group adjacent to single dU from the 3'-end in oligo is not involved into the electrostatic contact with UDG. It is found that UDG has the high affinity to its reaction product. An oligonucleotide containing a single 2'-deoxy-2'-aminouridine is a non-hydrolyzable substrate analog for UDG. 相似文献
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EG Pedachenko MV Khizhniak TI Makeeva AF Tanase?chum OV Tolstikhin 《Canadian Metallurgical Quarterly》1998,97(6):14-16
How many times have you been asked to participate in a meeting, forum, or task force to address a community health issue in the last few years? Opportunities seem to crop up almost weekly as non-profit organizations acclimate to meet changing needs and health systems continue to adapt to market forces. But participating in ongoing community projects, or even attending periodic meetings, draws time away from practice and professional obligations and limits an already modest supply of personal time. Is involvement in a community collaborative effort worth the time? And, if so, what are the benefits and challenges to physicians, health systems, and communities from this type of investment? 相似文献
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VA Bobrov VK Tashchuk AS Gavrish OV Sergienko IE Malinovskaia VA Shumakov LV Shkliar KB Monastyrskaia LN Likhtarovich 《Canadian Metallurgical Quarterly》1998,94(5):77-79
With the purpose of assessing the influence that platelet morphofunctional state may have on the degree of destabilization in patients with different forms of unstable angina we examined 198 patients using stress tests, Holter ECG monitoring, studying activation of thrombocytes with the aid of a luminescent-microscopy technique, and performing an analysis of aggregation. Important differences have been revealed in the studied parameters in those patients presenting with freshly detected and progressive stenocardia and with a developing, despite of the treatments administered, myocardial infarction, that might be caused by abnormal shifts in the thrombocyte intact/activated forms ratio. 相似文献
315.
T Joneson JA Fulton DJ Volle OV Chaika D Bar-Sagi RE Lewis 《Canadian Metallurgical Quarterly》1998,273(13):7743-7748
Kinase suppressor of Ras (KSR) is a loss-of-function allele that suppresses the rough eye phenotype of activated Ras in Drosophila and the multivulval phenotype of activated Ras in Caenorhabditis elegans. Genetic and biochemical studies suggest that KSR is a positive regulator of Ras signaling that functions between Ras and Raf or in a pathway parallel to Raf. We examined the effect of mammalian KSR expression on the activation of extracellular ligand-regulated (ERK) mitogen-activated protein (MAP) kinase in fibroblasts. Ectopic expression of KSR inhibited the activation of ERK MAP kinase by insulin, phorbol ester, or activated alleles of Ras, Raf, and mitogen and extracellular-regulated kinase. Expression of deletion mutants of KSR demonstrated that the KSR kinase domain was necessary and sufficient for the inhibitory effect of KSR on ERK MAP kinase activity. KSR inhibited cell transformation by activated RasVal-12 but had no effect on the ability of RasVal-12 to induce membrane ruffling. These data indicate that KSR is a potent modulator of a signaling pathway essential to normal and oncogenic cell growth and development. 相似文献
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During blood coagulation, soluble fibrinogen is converted to fibrin monomers that polymerize to form an insoluble clot. Polymerization has been described as a two-step process: the formation of double-stranded protofibrils and the subsequent lateral aggregation of protofibrils into fibers. Previous studies have shown that gamma chain residues Tyr-363 and Asp-364 have a significant role in polymerization, most likely in protofibril formation. To better define the role of these residues, we synthesized three fibrinogens with single substitutions at these two positions: Tyr-363 --> Ala, Asp-364 --> Ala, and Asp-364 --> His. We found that the release of fibrinopeptides A and B was the same for these variants and normal recombinant fibrinogen, showing that all variants had normal fibrin formation. In contrast, we found that polymerization was significantly delayed for both Ala variants and was almost nonexistent for the His variant. Clottability for the Ala variants was only slightly reduced, and fibrin gels were formed. Surprisingly, clottability of the His variant was substantially reduced, and fibrin gels were not formed. Our data suggest that both protofibril formation and lateral aggregation were altered by these substitutions, indicating that the C-terminal domain of the gamma chain has a role in both polymerization steps. 相似文献
319.
OV Kaliuzhin 《Canadian Metallurgical Quarterly》1998,253(1):104-108
Acute generalized sarcocystosis was diagnosed in a capercaillie (Tetrao urogallus) from Finland. Microscopic lesions were seen in the heart, lungs, spleen, liver, and brain. Protozoa were found in all organs, especially in the lungs and spleen. Only asexual stages were observed. The parasite divided by endopolygeny. Schizonts were usually 10 microm wide and up to 55 microm long. Merozoites are 3-4 microm long and 1.5-2.0 microm wide. Sarcocysts and sexual stages are unknown. The parasite was considered to be a species of Sarcocystis with an unknown life cycle. This is the first report of acute sarcocystosis in capercaillie from Finland. 相似文献
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