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111.
112.
113.
Brushing cytology in biliary tract obstruction 总被引:1,自引:0,他引:1
During a period of eight years (1980 to 1987), cytologic samples were obtained by brushing and reverse screw devices from 54 patients undergoing transhepatic cholangiography for evaluation of obstructive jaundice. Eight patients were excluded from this study, seven for inadequate follow-up and one because of unsatisfactory cytologic material. Of the remaining cases, 32 were cytologically diagnosed as adenocarcinomas; all but one patient proved to have malignant disease by histologic examination and/or through clinical follow-up. These included 21 pancreatic carcinomas, 6 bile duct carcinomas, 1 ampullary carcinoma, 1 gallbladder carcinoma and 2 metastatic carcinomas. In one case, the diagnosis of malignancy was found to be in error upon review of the cytologic smears. Of 14 patients with negative cytologic diagnoses, 7 were found to have malignant neoplasms and 7 had benign diseases. These findings indicate that, while a positive cytologic diagnosis is a reliable indicator of a malignant biliary obstruction, a negative result does not exclude malignancy. 相似文献
114.
115.
In a carrot (Daucus carota L.) cell line lacking the ability to undergo somatic embryogenasis, and in carrot and anise (Pimpinella anisum L.) cell lines in which embryogenesis could be regulated by presence or absence of 2,4-dichlorophen-oxyacetic acid (2,4-D), in the medium (+2,4-D=no embryogenesis,-2,4-D=embryo differentiation and development), the levels of endogenous gibberellin(s) (GA) were determined by the dwarfrice bioassay, and the metabolism of [3H]GA1 was followed. Embryos harvested after 14 d of subculture in-2,4-D had low levels (0.2–0.3 g g-1 dry weight) of polar GA (e.g. GA1-like), but much (3–22 times) higher levels of less-polar GA (GA4/7-like); GA1, GA4 and GA7 are native to these cultures. Conversely, the undifferentiated cells in a non-embryogenic strain, and proembryos of an embryogenic strain (+2,4-D) showed very high levels of polar GA (2.9–4.4 g g-1), and somewhat reduced levels of less-polar GA. Cultures of anise undergoing somatic embryo development (-2,4-D) metabolized [3H]GA1 very quickly, whereas proembryo cultures of anise (+2,4-D) metabolized [3H]GA1 slowly. The major metabolites of [3H]GA1 in anise were tentatively identified as GA8-glucoside (24%), GA8 (15%), GA1-glucoside (8%) and the 1(10)GA1-counterpart (2%). Thus, high levels of a GA1-like substance and a reduced ability to metabolize GA1 are correlated with the absence of embryo development, while lowered levels of GA1-like substance and a rapid metabolism of GA1 into GA8 and GA-conjugates are correlated with continued embryo development. Exogenous application of GA3 is known to reduce somatic embryogenesis in carrot cultures; GA4 was found to have the same effect in anise cultures. Thus, a role (albeit negative) in somatic embryogenesis for a polar, biologically active GA is implied.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- GA
gibberellin(s) or gibberellin-like substances
- GC-RC
gas chromatography-radiochromatogram counting
- HPLC
high-presare liquid chromatography
- Rt
retention time
- TLC
thinlaver chromatography 相似文献
116.
Summary Regulation of passive potassium ion transport by the external calcium concentration and temperature was studied on cell cultures of 3T3 mouse cells and their DNA-virus transformed derivatives. Upon lowering of external calcium concentration, passive potassium efflux generally exhibits a sharp increase at about 0.1mm. The fraction of calcium-regulated potassium efflux is largely independent of temperature in the cases of the transformed cells, but shows a sharp increase for 3T3 cells upon increasing temperature above 32°C. In the same range of temperature, the 3T3 cells exhibit the phenomenon of high-temperature inactivation of the residual potassium efflux at 1mm external calcium. At comparable cellular growth densities, the transformed cell lines do not show high-temperature inactivation of residual potassium efflux. These results are consistent with the notion of a decisive role of the internal K+ concentration in the cell-density dependent regulation of cell proliferation. In particular, the growth-inhibiting effect of lowering the external Ca2+ concentrations is considered as largely due to a rise of passive K+ efflux and a subsequent decrease of internal K+ concentration. The experimental data on the Ca2+ dependence of passive K+ flux are quantitatively described by a theoretical model based on the constant field relations including negative surface charges on the external face of the membrane, which cooperatively bind Ca2+ ions and may concomitantly undergo a lateral redistribution. The present evidence is consistent with acidic phospholipids as representing these negative surface charges.This work is dedicated to the memory of Max Delbrück (deceased March 10, 1981), in whose laboratory in 1966 the earlier version of the present theoretical model was developed by one of the authors. 相似文献
117.
Ernst Weber Evangelos Papamokos Wolfram Bode Robert Huber Ikunoshin Kato Michael Laskowski 《Journal of molecular biology》1981,149(1):109-123
The third domain of Japanese quail ovomucoid, a Kazal type inhibitor, has been crystallized and its crystal structure determined at 2.5 Å resolution using multiple isomorphous replacement techniques. The asymmetric unit contains four molecules. In the crystal the molecules are arranged in two slightly different octamers with approximate D4 symmetry. The molecules are held together mainly by interactions of the N-terminal residues, which form a novel secondary structural element, a β-channel.The molecule is globular with approximate dimensions 35 Å × 27 Å × 19 Å. The secondary structural elements are a double-stranded anti-parallel β-sheet of residues Pro22 to Gly32 and an α-helix from Asn33 to Ser44. The reactive site Lys18-Asp19 is located in an exposed loop. It is close to Asn33 at the N terminus of the helical segment. The polypeptide chain folding of ovomucoid bears some resemblance to other inhibitors in the existence of an anti-parallel double strand following the reactive site loop. 相似文献
118.
Danny M. Gee Gary M. Hathaway Richard H. Palmieri Ernst A. Noltmann 《Journal of molecular biology》1980,142(1):29-42
As a corollary to X-ray crystallographic work performed by H. Muirhead, detailed studies on crystalline pig muscle phosphoglucose isomerase have been conducted to establish its basic physical and chemical properties. The enzyme species being investigated by X-ray diffraction has been determined to be isoenzyme III. Its molecular weight in the native state was found to be 132,000, its s020,w value to be 7·25 S. The enzyme is composed of two subunits of equal molecular weight (66,000). Its amino acid composition is largely similar to that of rabbit muscle phosphoglucose isomerase, with the significant exception that the pig muscle isomerase contains only three sulfhydryl groups per polypeptide chain (two of them accessible to titration with p-mercuribenzoate) as compared with twice that number for the rabbit muscle enzyme. This low number of sulfhydryl groups is interpreted as being responsible for the ease with which heavy-atom, isomorphous derivatives could be prepared for the pig muscle enzyme by Shaw & Muirhead (1977). 相似文献
119.
Edward Ernst 《BMJ (Clinical research ed.)》1980,281(6250):1280-1281
120.
Anders
lund Hans Kindahl Ernst Oliw ke Lindgren Jan Bertil Larsson 《Prostaglandins & other lipid mediators》1980,19(5):791-803
Abortion or delivery were induced by extra-amniotic instillation of Rivanol during the second trimester in twelve patients and during the third trimester in two patients with fetal death and one patient with fetal acrania. Serial sampling of amniotic fluid was performed through a transabdominal catheter and the levels of free arachidonic acid (AA), prostaglandin F2α (PGF2α), prostaglandin E2 (PGE2), 6-keto-prostaglandin F1α (6-keto-PGF1α) and thromboxane B2 (TXB2) were determined. The levels of AA, PGF2α, PGE2, 6-keto-PGF1α and TXB2 in amniotic fluid increased significantly during induction with the exception of AA in fetal death which was high and remained constant during induction. Furthermore, PGF2α, 6-keto-PGF1α and TXB2 were all significantly correlated to AA.These observations suggested that free AA is released during Rivanol-induction of abortion and labour giving an increased synthesis of PGF2α, PGE2 prostacyclin and thromboxane A2 in the fetal membranes and the decidua but not in the fetus. This increase might be relevant for the initiation and progress of abortion and labour in these patients. 相似文献