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11.
Percutaneous aspiration biopsy of the pancreas using a heparinized 22-gauge fine needle was performed under ultrasonic guidance in five patients with benign pancreatic diseases and in 18 patients with pancreatic cancer. Using a heparinized needle and syringe, it was possible to make good smears containing abundant tumor cells and to obtain small tissue specimens. Using egg albumin as binding material, a new cell-block technic was developed to conveniently obtain histologic specimens. In this way, a correct diagnosis was made cytologically in all 23 patients suspected of having a pancreatic malignancy. Histologic specimens were obtained in 22 (95.6%) our of 23 patients. A correct diagnosis was established histologically in all patients from whom histologic materials were obtained. This procedure thus has proved a very reliable method for diagnosing pancreatic cancer.  相似文献   
12.
Osteoclast-like multinucleated cells were formed from mouse bone marrow mononuclear cells, and their morphology on coverslips and on calcified dentine slices was compared by means of transmission electron microscopy. Addition of 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] to bone marrow cells cultured on coverslips greatly stimulated the formation of multinucleated cells within 8 days. These multinucleated cells had the cytological features of osteoclasts (abundant pleomorphic mitochondria, a large number of vacuoles and lysosomes, many stacks of Golgi membranes, and an extensive canalicular system), but they developed neither ruffled borders nor clear zones. The multinucleated cells appeared to result from direct fusion of mononuclear progenitor cells, whose structural features were similar to those of multinucleated cells. Like isolated osteoclasts, both multinucleated cells and their precursors exhibited an intense reaction for tartrate-resistant acid phosphatase (TRACP) in the cisterns of endoplasmic reticulum and lysosomes. Multinucleated cells formed from alveolar macrophages in the presence of 1α,25(OH)2D3 were totally negative for TRACP reaction. When marrow cells were cultured on dentine slices in the presence of 1α,25(OH)2D3, some of the multinucleated cells were located in the shallow resorption lacunae of dentine surfaces, and they developed the characteristic ruffled borders and clear zones. The narrow extracellular spaces of the ruffled borders, the adjacent pale endocytotic vacuoles, and the dark lysosomes located in the perinuclear cytoplasm of the multinucleated cells contained numerous apatite crystals delete in resorption lacunae. These results indicate that (1) the multinucleated cells formed on coverslips from mouse marrow cells treated with 1α,25(OH)2D3 exhibit non-functional basic features of osteoclast morphology, and (2) differentiation of the multinucleated cells into functional osteoclasts requires some components of calcified dentine.  相似文献   
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The stereochemistry of the copolymerization of optically active phenylepoxyethane ( 5 ) with carbon dioxide using a diethylzinc/water system as catalyst was investigated. The optically active copolymer, poly(oxycarbonyloxy-2-phenylethylene) ( 1 ), was hydrolyzed and the oxy-2-phenylethylene unit was isolated in the form of 1,2-bis(trimethylsilyloxy)-1-phenylethane ( 3 ). The determination of the optical activity of this ether led to the conclusion that the ring opening of 5 takes place predominantly at the methineoxygen linkage accompanying an inversion in the copolymerization. This fact is in sharp contrast with the stereochemistry of the copolymerization of carbon dioxide with 1,2-epoxypropane in which the ring opening takes place at the methylene-oxygen linkage.  相似文献   
15.
Lateral association of sphingolipids and cholesterol is considered to form membrane microdomains such as “lipid rafts” obtainable as a detergent-resistant membrane microdomain (DRM) fraction after solubilization with a non-ionic detergent and density gradient centrifugation. Since not only sphinogolipids and cholesterol, but also functional lipids such as phosphatidylinositol 4,5-bisphosphate (PIP2) are reported to be localized in DRM prepared from several cultured cells, this domain is considered to be a platform mediating lipid-signaling. Although PIP2 is considered to have pivotal roles in the nervous system, little information is available on the localization of PIP2 in the DRM within the synaptic plasma membrane (SPM) obtained from matured rat brains. In this study, in order to know the localization of PIP2 in SPM-derived DRM, we measured the amount of PIP2 in SPM and SPM-derived DRM, by the thin-layer chromatography blotting method, using a GST-fusion protein of the pleckstrin-homology domain of phospholipase Cδ1 as a PIP2 binding probe. About 10% of the PIP2 in SPM was recovered in DRM. In contrast, over 40% recovery was observed for the membrane cholesterol and sphingomyelin, and about 30% recovery was observed for phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine in the DRM were detected using the thin-layer chromatography method. Since the recovery of proteins in DRM was about 10%, the result indicates that there occurs no enrichment of PIP2 in DRM prepared from SPM.  相似文献   
16.
Copolymerization of N-carboxy-γ-benzyl-L -glutamate anhydride and ethylene oxide or DL-propylene oxide was carried out in the presence of triethylaluminum or diethylzine as catalyst with (or without) dioxane as solvent. From the data obtained by nuclear magnetic resonance spectroscopy, optical rotatory dispersion measurements, infrared absorption spectroscopy and turbidimetry, it was concluded that the copolymer obtained by the triethylaluminum catalyst consisted of two parts, peptide-block part and random or alternate part, while diethylzinc catalyst resulted in the formation of a less random copolymer only. In dioxane, formation of peptide-block part by triethylaluminum was suppressed to some extent.  相似文献   
17.
The system diethylzinc/optically active alcohol was examined as catalyst for asymmetric-selective polymerization of propylene oxide. Optically active alcohols with rigid structure are effective for the asymmetric selection. D (–)-1-Methoxypropanol-2 as well as poly(D -propylene oxide) of low molecular weight with hydroxyl end groups select L (–)-propylene oxide. ?Catalyst control”? mechanism of the stereoselection in the polymerization is suggested on this and other bases.  相似文献   
18.
 Recent studies have identified a family of proteins referred to as cyclins, which control the cell cycle. Cyclin B1 activates cdc2, which regulates cell progression through the G2 and M phases. The main aim of this study was to examine the relationships between the cyclin B1 expression in human esophageal squamous cell carcinoma (SCC) and clinicopathological factors and prognosis of the patients. Eighty-seven cases of primary human SCC consecutively obtained at esophagectomy were immunohistochemically studied using an anti-human cyclin B1 protein antibody (2H1-H6). The relationship between cyclin B1 expression and clinicopathological factors, including prognosis, were also statistically assessed. Positive immunostaining of cancer cells, mainly in the cytoplasm, was detected in 72.4% (63/87): heterogeneous pattern in 37.9 % (33/87) and homogeneous pattern in 34.5% (30/87). The prevalence of cyclin B1 expression was significantly higher in cases with invasion deeper than the muscularis propria (P<0.005) and with venous invasion (P<0.01) than in other cases. Patients whose SCCs expressed high levels of cyclin B1 protein had a significantly poorer prognosis than did the other patients (P<0.05). Multivariate analysis demonstrated that cyclin B1 status was an important factor affecting survival (P<0.05). These findings demonstrated that overexpression of cyclin B1 protein is associated with tumor behavior and prognosis for patients with human esophageal SCC. Received: 25 June 1998 / Accepted: 21 October 1998  相似文献   
19.
Novel segmented multiblock copolymers ( 7 ) were synthesized by linking poly(ethylene oxide) (PEO) blocks with poly(β-benzyl L -aspartate)(PBLA) blocks via urethane and urea bonds, which were formed by the reaction of 4,4′-methylenediphenyl isocyanate ( 5 ) with the terminal hydroxyl groups of α-hydro-ω-hydroxypoly(oxyethylene) ( 4 ) and the terminal amino groups of poly(β-benzyl L -aspartate)-block-iminohexamethyleneimino-block-poly(β-benzyl L -aspartate) ( 3 ) [prepared from 1,6-hexanediamine ( 1 ) and β-benzyl L -aspartate N-carboxy anhydride ( 2 )], respectively. Membranes with various water contents were obtained from these copolymers by changing the lengths of the PEO and PBLA segments. The study of the permeation of 1-phenyl-1,2-ethanediol, vitamin B12 and myoglobin through the membranes showed a high dependency of the permeability on the molecular weight of the solutes.  相似文献   
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