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71.
T M Chang F C MacIntosh S G Mason 《Canadian journal of physiology and pharmacology》1966,44(1):115-128
72.
73.
74.
75.
76.
R W Mason I R Edwards L C Fisher 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1989,93(2):407-411
1. The teratogenicity of sodium dichromate (2 mg Cr/kg), sodium arsenate (5 mg As/kg) and copper sulphate (2 mg Cu/kg) in female Wistar rats was studied following the administration of the test compounds separately and in their various combinations on gestation day 8. 2. The test compounds administered separately and the combination of dichromate plus Cu2+ were non-fetotoxic and either non- or weakly teratogenic, whereas arsenate/Cu2+ was both weakly fetotoxic and teratogenic. 3. Dichromate/arsenate and dichromate/arsenate/Cu2+ caused a marked decrease in mean fetal weight and an increased incidence of fetal resorption and abnormality formation. 相似文献
77.
Immunocytochemical analysis of cytocentrifuged fine needle aspirates. A study based on lung tumors aspirated in vitro 总被引:2,自引:0,他引:2
D C Brown K C Gatter M S Dunnill D Y Mason 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1989,11(2):140-145
The value of Cytospin preparations of fine needle aspiration (FNA) biopsy material for immunocytochemical analysis was investigated using aspirates obtained from 23 resected human lung tumors. The results were compared with those on cryostat sections from the same tumors. The Cytospin preparations of the FNA biopsies gave the best immunostaining reactions and enabled a comprehensive range of monoclonal antibodies (MAbs) to be utilized. The quality of the Cytospin immunostaining compared favorably with that on cryostat sections of the same tumors and generally yielded a similar immunophenotype. However, the Cytospin preparations were not suitable for staining with MAb Ki67, which detects an antigen associated with cellular proliferation. With Ki67, conventionally prepared smears were much superior and enabled an assessment of tumor growth fraction that concurred with the growth fraction calculated from cryostat sections in most cases. 相似文献
78.
A J Mason L M Berkemeier C H Schmelzer R H Schwall 《Molecular endocrinology (Baltimore, Md.)》1989,3(9):1352-1358
We report here the complete amino acid sequence of the human inhibin beta B-subunit as deduced from the sequence of cDNA and genomic clones. The primary translation product of the beta B mRNA predicts a protein of 407 amino acids, containing a prepro region of 292 amino acids separated by basic amino acids from the mature C-terminal 115 amino acids. Mammalian tissue culture cells transfected with a beta B-subunit expression plasmid secreted an activin B homodimer of approximately 22K mol wt. Coexpression of the beta A- and beta B-subunit mRNAs resulted in the secretion of the three forms of activin, A, AB, and B. Purified activin B was shown to elicit FSH release in an in vitro pituitary assay and trigger the accumulation of hemoglobin in K562 cells. The potency of activin B in both of these assays (ED50 approximately 2 ng/ml) was indistinguishable from that observed for activin A. 相似文献
79.
The induction of 1-hydroxylase in alveolar macrophages by tumor necrosis factor-alpha (TNF) was examined in view of recent evidence suggesting that local production of 1,25-(OH)2D3 may play a role in the regulation of immune functions. Incubation of pulmonary alveolar macrophages from normal human subjects with recombinant TNF caused a 2- to 10-fold increase in 25-hydroxyvitamin D3-1-hydroxylase activity. The dose-response curve was linear over the range 0.05-5.0 IU/ml, and no further increase was seen at higher concentrations. The increase in 1-hydroxylase activity was present after 12 h and reached a maximum after 3 days. The effect of TNF was inhibited in a dose-dependent manner by the presence of 1,25(OH)2D3 (10(-10)-10(-8) M) in the incubation media for 5 days but was unaffected by 10(-9) M 1,25(OH)2D3 after 12 h. The enhancement of macrophage 1-hydroxylase activity by TNF was comparable to that induced by gamma interferon (IFN) but the effects of maximal doses of both agents were not additive. The presence of antibody to TNF resulted in a 76% inhibition of TNF-induced 1-hydroxylase but had no significant effect on IFN-induced 1-hydroxylase activity. 相似文献
80.
Effect of cytoplasmic acidification on the membrane potential of T-lymphocytes: Role of trace metals
Summary The effect of lowering intracellular pH on the membrane potential (E
m
) of rat thymic lymphocytes was studied using the potential-sensitive dyebis-oxonol. Cells were acid loaded by addition of the electroneutral K+/H+ exchanging ionophore nigericin. Acidification to pH 6.3 in Na+-free solution resulted in a biphasic change inE
m
: an early transient hyperpolarization followed by a sustained depolarization. These changes were associated with a rise in cytosolic free Ca2+ ([Ca2+]
i
). The hyperpolarization was eliminated when the change in [Ca2+]
i
was prevented using BAPTA, an intracellular Ca2+ chelator. Moreover, a similar hyperpolarization was elicited by elevation of [Ca2+]
i
at physiological pH
i
using ionomycin, suggesting involvement of Ca2+-activated K+ channels. In contrast, the depolarization phase could not be mimicked by raising [Ca2+]
i
with ionomycin. However, intracellular BAPTA effectively inhibited the acidificationinduced depolarization. Inhibition was also obtained by extracellular addition of EGTA or dithiothreitol, even when the external free Ca2+ concentration remained unaltered. These observations suggested a possible role of contaminating trace metals. Cytosolic acidification is envisaged to induce intracellular accumulation of one or more trace metals, which induces the observed changes inE
m
. Accordingly, similar changes inE
m
can be induced without acidification by the addition of small amounts of Cu2+ to the medium. The ionic basis of theE
m
changes induced by acidification and the significance of these observations are discussed. 相似文献