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91.
Double-stranded RNA unwinding and modifying activity is detected ubiquitously in primary tissues and cell lines. 总被引:19,自引:4,他引:15
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R W Wagner C Yoo L Wrabetz J Kamholz J Buchhalter N F Hassan K Khalili S U Kim B Perussia F A McMorris et al. 《Molecular and cellular biology》1990,10(10):5586-5590
A double-stranded RNA unwinding and modifying activity was found to be present in a wide range of tissues and cell types. The level of activity did not vary significantly with respect to the state of cell differentiation, cell cycle, or transformation. Thus, the unwinding and modifying activity, localized in the nucleus in somatic cells and capable of converting many adenosine residues to inosine, appears to be one of the housekeeping genes. 相似文献
92.
93.
Hans Jørgen Nielsen Henrik Nielsen Flemming Moesgaard Niels Tvede Kim Klarlund Bendt Mansa Aage Drivsholm 《Cancer immunology, immunotherapy : CII》1990,32(3):201-205
Summary Multiple myeloma is characterized by an increased susceptibility to infections and to other malignancies. In a double-blind, placebo-controlled study the potential impact of immunomodulation by ranitidine was studied in 20 patients with multiple myeloma. Three patients were untreated, while 17 after previous cytotoxic therapy were in a stable phase of their disease. All were without clinical signs of infections and at that time had not been treated with other immunomodulating agents. The patients were randomized to oral ranitidine 300 mg twice a day for 21 days or placebo, and several immunological parameters related to multiple myeloma were studied. The blood monocyte chemotactic response was improved in patients treated with ranitidine, and superoxide anion production increased from 2.02 nmol/min to 3.86 nmol/min (median values), while it was unchanged in patients given placebo (2.19–2.25 nmol/min) (P <0.005 between groups). Among ranitidine-treated patients spontaneous NK cell activity was unchanged, while in vitro interleukin-2- and interferon--stimulated NK cell activity decreased (P <0.03, respectively). As production of oxygen radicals constitutes an important mechanism of monocyte killing activity against microorganisms and probably against malignant cells, it is suggested that ranitidine may be of beneficial impact in the treatment of multiple myeloma. 相似文献
94.
M Bibbo D H Kim C di Loreto H E Dytch H Galera-Davidson D Thompson D L Richards H G Bartels P H Bartels 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1990,12(4):229-236
In research for the development of a computer-aided workstation for the objective grading of prostatic carcinoma, tissue architectural (histometric) features were analyzed in ten cases each of well-differentiated, moderately differentiated and poorly differentiated carcinoma (as subjectively graded by the consensus of a panel of experts). Sections were cut at 4 microns, stained by the Feulgen reaction and digitized by two different video-based photometric systems. Some images were interactively segmented, considering the histometric clues to be studied; others were automatically segmented by an expert system-guided technique. The latter procedure produced good results, with over 90% of the nuclei judged to be correctly segmented in 64% of the fields studied and over 80% in another 24% of the fields. While the number of nuclei per field provided some separation of well-differentiated from other lesions, the number of nuclei per gland distinguished between well-differentiated and moderately differentiated lesions. Simplicial decomposition of the images also provided a measure of the degree of differentiation, as did the "texture" of the nuclear placement, based on two run-length statistics. Combination of the run-length features distinguished the three categories of lesions with statistical significance. The results of this study provided insights into the problems (such as the effect of field boundaries) faced in the design of an computer-aided grading system. They also showed the value of expert system-guided scene segmentation and of such histometric features as the field cellularity and the number of nuclei per gland for the discrimination between lesions of different grades of differentiation. 相似文献
95.
A physical map of the human salivary proline-rich protein gene cluster covers over 700 kbp of DNA 总被引:5,自引:0,他引:5
By using a linking library, we have experimentally linked, ordered, and spaced four of the six loci that constitute the human salivary proline-rich protein (PRP) multigene family. The methods used for mapping these four PRP genes may be useful in other multigene systems in which no probes unique to each member of genes are available, but in which some enzyme site that occurs only once in each member of the family can be found. The remaining two PRP loci have been provisionally mapped and linked within the gene cluster primarily on the basis of the resulting order giving a simple map. The order of the six loci that most simply accounts for our data is PRB2, PRB1, PRB4, PRH2, PRB3, and PRH1. The PRP gene cluster spans at least 700 kbp on chromosome 12 at p13.2. A scheme for the evolution of the cluster that requires an initial gene duplication followed by three unequal but homologous crossovers is given. 相似文献
96.
Masatsugu Hatakeyama Tetsuya Nakamura Kyu Beom Kim Masami Sawa Tikahiko Naito Kugao Oishi 《Development genes and evolution》1990,198(7):389-394
Summary Mature eggs dissected from ovaries of unmated females of Athalia rosae (Hymenoptera: Tenthredinidae), if placed on a filter-paper soaked with distilled water, are activated and develop to haploid males. Occasionally, however, diploid females develop from these artificially activated eggs. Treatment of mature unfertilized eggs dissected from diploid females with ice-cold temperatures immediately before activation and with a high temperature (36° C) upon and immediately after activation resulted in the production of diploid males, diploid females, triploid females and gynandromorphs at high frequency. The same treatment of mature unfertilized eggs dissected from triploid females resulted in the production of only triploid survivors. These results, together with the results on the segregation of a marker mutation, yellow fatbody (yfb), appear to indicate that meiotic divisions were complete in the treated eggs, and that all four nuclei became potentially capable of participating in development with or without automictic fusion.Studies on the sawfly, Athalia rosae (Insecta, Hymenoptera, Tenthredinidae), part V 相似文献
97.
Transforming growth factor-beta: multifunctional regulator of differentiation and development 总被引:8,自引:0,他引:8
A B Roberts K C Flanders U I Heine S Jakowlew P Kondaiah S J Kim M B Sporn 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》1990,327(1239):145-154
Transforming growth factors-beta (TGF-beta) are 25 kilodalton (kDa) homodimeric peptides with multifunctional actions controlling the growth, differentiation and function of a broad range of target cells of both epithelial and mesenchymal derivation. They are expressed early in embryogenesis and their tissue-specific and developmentally dependent expression is strongly suggestive of an essential role in particular morphogenetic and histogenetic events. Five distinct TGF-beta s have been characterized so far, with 65-80% homology to each other. By using both molecular biological and immunohistochemical techniques, we are currently attempting to define specific sites of expression of the different TGF-beta s and to determine whether TGF-beta s 1-5 might have unique functions in development and in the mature organism. Comparative study of the promoter regions for the different TGF-beta s and for any particular TGF-beta in different species is also underway. Mechanistically, TGF-beta s act to control gene expression of their target cells, many of their actions converging on a complex, multifaceted scheme of control of matrix proteins and their interactions with cells; these effects on matrix are thought to mediate many of the effects of TGF-beta on development. 相似文献
98.
Purification of multiple erythroid cell proteins that bind the promoter of the alpha-globin gene. 总被引:9,自引:6,他引:3
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Three erythroid cell factors that bind the murine alpha-globin promoter were enriched more than 1,000-fold by conventional and DNA sequence affinity chromatography. Visualization of enriched polypeptides revealed simple patterns suggesting that each binding activity was purified. Two of the purified proteins, alpha-CP1 and alpha-CP2, have been shown previously to interact with distinct binding sites that overlap in the alpha-globin CCAAT box. Affinity purification of alpha-CP1 revealed seven polypeptides with Mrs raging from 27,000 to 38,000. In contrast, purified alpha-CP2 was made up of a polypeptide doublet with Mrs of 64,000 and 66,000. The third purified binding activity, alpha-IRP, interacted with sequences that formed an inverted repeat (IR) between the alpha-globin CCAAT and TATAA boxes. Affinity-purified alpha-IRP was made up of a single polypeptide with an Mr of 85,000. We confirmed that the purified polypeptides corresponded to alpha-CP1-, alpha-CP2-, and alpha-IRP-binding activities by UV cross-linking experiments (alpha-CP2 and alpha-IRP) or by renaturation of binding activity after elution of polypeptides from sodium dodecyl sulfate-polyacrylamide gels (alpha-CP1 and alpha-CP2). The apparent complexity of the polypeptides accounting for alpha-CP1 binding activity prompted a further physical characterization of this factor. Sedimentation of affinity-purified alpha-CP1 in glycerol gradients containing 100 mM KCl showed that all seven polypeptides migrated as a complex that cosedimented with alpha-CP1-binding activity. In contrast, when sedimented in glycerol gradients containing 500 mM KCl, alpha-CP1 dissociated into at least two components. Under these conditions, alpha-CP1-binding activity was reduced or lost. Activity was reconstituted, however, by combining fractions that were enriched in the two components. These results were confirmed by experiments in which we showed that alpha-CP1-binding activity can be recovered only by combining distinct sets of polypeptides that were isolated and renatured from sodium dodecyl sulfate-polyacrylamide gels. Our results suggest that the seven polypeptides visualized after affinity purification of alpha-CP1 interact to form a heterotypic complex (or set of complexes) required for alpha-CP1-binding activity. 相似文献
99.
Evangelia G. Kranias Ramesh C. Gupta Gyorgyi Jakab Hae Won Kim Nancy A. E. Steenaart Stephen T. Rapundalo 《Molecular and cellular biochemistry》1988,82(1-2):37-44
Summary Canine cardiac sarcoplasmic reticulum is phosphorylated by adenosine 3,5-monophosphate (cAMP)-dependent and by calcium · calmodulin-dependent protein kinases on a 27 000 proteolipid, called phospholamban. Both types of phosphorylation are associated with an increase in the initial rates of Ca2+ transport by SR vesicles which reflects an increased turnover of elementary steps of the calcium ATPase reaction sequence. The stimulatory effects of the protein kinases on the calcium pump may be reversed by an endogenous protein phosphatase, which can dephosphorylate both the CAMP-dependent and the calcium · calmodulin-dependent sites on phospholamban. Thus, the calcium pump in cardiac sarcoplasmic reticulum appears to be under reversible regulation mediated by protein kinases and protein phosphatases. 相似文献
100.
Search for the optimal sequence of the ribosome binding site by random oligonucleotide-directed mutagenesis. 总被引:5,自引:2,他引:3
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Synthetic DNA duplexes corresponding to the ribosome binding site (RBS) were synthesized through the phosphite method on solid support. The synthetic RBS DNA with partial random sequences was inserted into an appropriate site between the lpp-lac promoter and the beta-galactosidase structural gene in plasmid pMKT2. The level of beta-galactosidase expression was correlated with the color intensity of the recombinant colonies on X-gal plates. The bluest colonies were isolated and characterized with respect to beta-galactosidase enzyme activity and RBS sequence. There was good correlation between color intensity and the level of the enzyme activity, and this provided a reliable phenotypic screening method in the search for the optimal regulatory sequences. Novel RBS sequences obtained here show not only the unique nucleotide distribution, but also strong complemetarity to the 3' end region of 16S rRNA, from which could be deduced a generalized RBS sequence, the position of the SD region, and the 16S rRNA position mediated during translation initiation. 相似文献