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Alfonso Gonzalez Terry D. Oberley Janice L. Schultz Jennifer Ostrom Jonathan J. Li 《In vitro cellular & developmental biology. Animal》1993,29(7):562-573
Summary Primary diethylstilbestrol-induced kidney tumors from Syrian hamsters were grown in vitro and maintained in culture for 6
mo. Combined immunohistochemical studies using antibodies to intermediate filaments and ultrastructural studies of tumor cells
in culture exhibited characteristics similar to tumor cells in vivo. Furthermore, the cells manifested transformed properties
in culture; they grew both as multilayered colonies attached to the tissue culture substrate and as floating multicellular
colonies (spheroids). When cultured cells were injected into diethylstilbestrol-treated recipient hamsters, tumors developed
at the injection sites. In contrast, renal tubules or whole kidney cortex from control hamsters cultured in the same medium
underwent only short-term growth, with senescence developing after approximately 1 mo. However, cell cultures of kidney cortex
from animals treated in vivo for 5 mo. with diethylstilbestrol formed a cell line. This diethylstilbestrol-induced cell line
has been maintained in culture for 1.5 yr and has the following characteristics: a) it is anchorage-dependent, b) it is negative
in in vivo tumorigenicity tests, and c) cultured cells are histochemically and ultrastructurally similar to cultured tumor
cells. This culture system should prove to be of use in studying hormonal carcinogenesis in vitro.
This study was supported by the Medical Research Service, Department of Veterans Affairs, Washington, DC, and by grant CA-22008
from the National Cancer Institute, NIH, DHHS, Bethesda, MD. 相似文献
75.
ELENA RAEVSKAYA MARCO VECOLI WIESAW BEDNARCZYK MARCO TONGIORGI 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2004,37(1):97-111
Billingen (Lower Arenig/Lower Ordovician) sediments of the St. Petersburg region, northwest Russia and the Leba area, northern Poland of the East European Craton yield acritarch assemblages, which are largely homogenous though displaying minor compositional differences that probably reflect a gradient from inner to outer shelf environments. Comparison with coeval acritarch microflora from the Yangtze Platform, South China, shows an overall similarity between Baltoscandian and South Chinese phytoplankton. The widespread uniformity in the fossil microphytoplankton may be related to the extensive global 'evae' sea-level transgression, which characterized the Billingen time. This suggests that during the Tremadoc through early Arenig times, acritarch assemblages displayed essentially an undifferentiated cold-water and oceanic character along the whole margin of Perigondwana in the South, as well as on the South Chinese and Baltic platforms, at middle latitudes (Mediterranean oceanic Realm). Despite this overall similarity, however, some typical taxa of the high-latitude Mediterranean Province (Arbusculidium, Coryphidium and Striatotheca) occur in South China, but are absent in Baltica. This discrepancy is explained as caused by differences in climatic and physiographic conditions that prevailed at the two palaeocontinents at this time. The inferred pattern of oceanic circulation during the Lower Ordovician is consistent with the palynological evidence of a prevailing warmer climate in Baltica than in South China, although the two palaeocontinents occupied the same palaeolatitudinal position. 相似文献
76.
The Metabolism of Quinate in Pea Roots (Purification and Partial Characterization of a Quinate Hydrolyase) 总被引:2,自引:0,他引:2
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A quinate (QA) hydrolyase was isolated from pea (Pisum sativum L.) roots. The enzyme converts QA into shikimate by elimination of water. The enzymatic reaction is independent of cofactors and divalent cations. The QA hydrolyase was purified about 1,600-fold to apparent electrophoretic homogeneity in three steps, including bovine serum albumin-affinity chromatography. The enzyme forms oligomers and/or complexes with bovine serum albumin and ovalbumin. The monomer molecular weight of the enzyme is about 15,000. The hydrolyase shows regular Michaelis-Menten kinetics with a Km, of 2.0 mM for QA. Compartmentation studies reveal that the QA hydrolyase is localized in plastids. The QA hydrolyase may function in channeling imported QA into the shikimate pathway to support aromatic amino acid biosynthesis in plastids. 相似文献
77.
Mammalian DNA ligase III: molecular cloning, chromosomal localization, and expression in spermatocytes undergoing meiotic recombination. 总被引:14,自引:4,他引:10
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78.
Expression of TRPC3 in Chinese Hamster Ovary Cells Results in Calcium-activated Cation Currents Not Related to Store Depletion 总被引:16,自引:0,他引:16
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Christof Zitt Alexander G. Obukhov Carsten Strübing Andrea Zobel Frank Kalkbrenner Andreas Lückhoff Günter Schultz 《The Journal of cell biology》1997,138(6):1333-1341
TRPC3 (or Htrp3) is a human member of the trp family of Ca2+-permeable cation channels. Since expression of TRPC3 cDNA results in markedly enhanced Ca2+ influx in response to stimulation of membrane receptors linked to phospholipase C (Zhu, X., J. Meisheng, M. Peyton, G. Bouley, R. Hurst, E. Stefani, and L. Birnbaumer. 1996. Cell. 85:661–671), we tested whether TRPC3 might represent a Ca2+ entry pathway activated as a consequence of depletion of intracellular calcium stores. CHO cells expressing TRPC3 after intranuclear injection of cDNA coding for TRPC3 were identified by fluorescence from green fluorescent protein. Expression of TRPC3 produced cation currents with little selectivity for Ca2+ over Na+. These currents were constitutively active, not enhanced by depletion of calcium stores with inositol-1,4,5-trisphosphate or thapsigargin, and attenuated by strong intracellular Ca2+ buffering. Ionomycin led to profound increases of currents, but this effect was strictly dependent on the presence of extracellular Ca2+. Likewise, infusion of Ca2+ into cell through the patch pipette increased TRPC3 currents. Therefore, TRPC3 is stimulated by a Ca2+-dependent mechanism. Studies on TRPC3 in inside-out patches showed cation-selective channels with 60-pS conductance and short (<2 ms) mean open times. Application of ionomycin to cells increased channel activity in cell-attached patches. Increasing the Ca2+ concentration on the cytosolic side of inside-out patches (from 0 to 1 and 30 μM), however, failed to stimulate channel activity, even in the presence of calmodulin (0.2 μM). We conclude that TRPC3 codes for a Ca2+-permeable channel that supports Ca2+-induced Ca2+-entry but should not be considered store operated. 相似文献
79.
Identification of two homologs of the Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) in retroperitoneal fibromatosis of different macaque species. 总被引:10,自引:4,他引:6
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T M Rose K B Strand E R Schultz G Schaefer G W Rankin Jr M E Thouless C C Tsai M L Bosch 《Journal of virology》1997,71(5):4138-4144
Simian retroperitoneal fibromatosis (RF) is a vascular fibroproliferative neoplasm which has many morphological and histological similarities to human Kaposi's sarcoma (KS). Like epidemic KS in AIDS patients, RF is highly associated with an immunodeficiency syndrome (simian acquired immunodeficiency syndrome [SAIDS]) caused by a retrovirus infection. Recently, a new gammaherpesvirus, called Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8), has been identified in KS tumors, suggesting that KS has a viral etiology. Our previous experimental transmission studies and epidemiological data suggest that RF also has an infectious etiology. In order to determine whether a similar virus is also associated with RF, we have assayed for the presence of an unknown herpesvirus using degenerate PCR primers targeting the highly conserved DNA polymerase genes of the herpesvirus family. Here we provide DNA sequence evidence for two new herpesviruses closely related to KSHV from RF tissues of two macaque species, Macaca nemestrina and Macaca mulatta. Our data suggest that KSHV and the putative macaque herpesviruses define a new group within the subfamily Gammaherpesvirinae whose members are implicated in the pathogenesis of KS and KS-like neoplasms in different primate species. 相似文献
80.
Toews, M. L., E. E. Ustinova, and H. D. Schultz.Lysophosphatidic acid enhances contractility of isolated airwaysmooth muscle. J. Appl. Physiol.83(4): 1216-1222, 1997.The effects of the simple phospholipidmediator lysophosphatidic acid (LPA) on the contractile responsivenessof isolated tracheal rings from rabbits and cats were assessed. In bothspecies, LPA increased the contractile response to the muscarinicagonist methacholine, but LPA did not induce contraction on its own.Conversely, LPA decreased the relaxation response to the-adrenergic-agonist isoproterenol in both species. Concentrations ofLPA as low as 108 M wereeffective, and the effects of LPA were rapidly reversed on washing.Phosphatidic acid was much less effective, requiring higherconcentrations and producing only a minimal effect. Contractions induced by serotonin and by substance P also were enhanced by LPA, butKCl-induced contractions were unaffected. LPA inhibited theisoproterenol-induced relaxation of KCl-precontracted rings, similar toits effects on methacholine-precontracted rings, and relaxation inducedby the direct adenylyl cyclase activator forskolin was inhibited in amanner similar to that induced by isoproterenol. Epithelium removal didnot alter the contraction-enhancing effect of LPA. The ability of LPAto both enhance contraction and inhibit relaxation of airway smoothmuscle suggests that LPA could contribute to airway hypercontractilityin asthma, airway inflammation, or other types of lung injury. 相似文献