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91.
W. Ken Busfield Ian M. G. Cowie M. A. Sattar Mondal 《Macromolecular chemistry and physics.》1979,180(7):1775-1786
Two series of block copolymers have been synthesized comprising of soft polytrifluoroacetaldehyde (polyacetal) segments and of hard 4,4′-methylenedi(phenyl isocyanate)/cis-cyclohexane-1,4-diol polyurethane segments. The series-A copolymers in which the soft segments were directly bound to the hard segments had significantly lower thermal stability than the series-B copolymers in which the soft segments were linked to the hard segments by sebacic ester units. In both series the thermal stability decreased with increasing soft segment content. The series-A copolymers exhibited two thermal transitions both characteristic of Tg's and separated by about 60 K. In contrast the series-B copolymers exhibited two characteristic Tg's separated by 200–250 K, depending on composition, together with an additional endothermic transition at about ambient temperature. All transitions for both series decreased with increasing soft segment content. The observations have been compared with those of other polyether and polyester based polyurethanes. 相似文献
92.
Ken SAITO Hideo SHIMIZU Takeshi YOKOYAMA Katsuya KAWATA Takanori MATSUMURA Yasuhiko MORIOKA 《Pathology international》1983,33(2):249-256
Four cases of Ischemic enterocolitis without arterio–occlusive lesion were described. Three cases were associated with sigmoid colon carcinomas. Ischemic lesions developed anal to the carcinomas in two cases, and oral to sigmoidostomy to relieve intestinal obstruction by carcinoma in one case. One other case was associated with inguinal hernia. Grossly, ischemic lesions involved relatively short intestinal segments, and the ischemic colonic lesions were not related to teniae coli. Extensive veno–occlusive lesions were discovered in a case of ischemic stricture of the ileum, which had been incarcerated in the right inguinal hernia. Reversible mechanical occlusion of the intestinal vessels caused by transient or recurrent intestinal strangulation is the most probable cause of these ischemic lesions., ACTA PATHOL. JPN. 33: 249–256, 1983. 相似文献
93.
Satoh Y Ishikawa Y Miyoshi T Mukai H Okumura S Nakagawa K 《Virchows Archiv : an international journal of pathology》2003,442(2):173-178
Pulmonary metastasis from low-grade endometrial stromal sarcomas (ESSs) occasionally are found after long, disease-free periods, mostly as incidental histological or radiological discoveries. We describe a case of low-grade ESS presenting as nodular pulmonary metastases finally diagnosed by estrogen-receptor staining, cytogenetic and fluorescence in situ hybridization (FISH) analyses, and perusal of the histology of hysterectomy material. An abnormal nodule in the lung field was discovered by means of chest X-ray of a 47-year-old woman. She had been disease free for 13 years after hysterectomy for an alleged leiomyoma. A computed tomographic scan revealed nodules, with fluctuation in size over the 2-year period, in both lungs. Finally the lesion in the left lung was resected, and pulmonary endometriosis was suspected because of the lack of stromal cell nuclear atypia and positive immunohistochemical reactions for estrogen and progesterone receptors. However, a characteristic karyotype was identified cytogenetically: 46, XX, t(7;17)(p15;q11), the translocation of which, specific to ESS, was confirmed by FISH analysis. A final diagnosis of pulmonary metastases from an ESS could be made by reviewing the histology of the previous uterine tumor. In this case, metastatic lesions from an ESS showed a decrease as well as an increase in size, despite the malignant potential. Immunostaining for estrogen and progesterone receptors and cytogenetic and FISH analyses, together with clinical information on the past gynecological history, are valuable diagnostic keys. 相似文献
94.
Mireille Lahoud David Vremec Richard L. Boyd Ken Shortman 《Clinical & developmental immunology》1993,3(2):103-112
Thymic nurse cells (TNC), multicellular complexes consisting of lymphoid cells
enclosed within cortical epithelial cells, were isolated from mouse thymus by a modified
procedure allowing immunofluorescent labeling and flow cytometric analysis of their
lymphoid contents (TNC-L). Collagenase was the only protease used for tissue
digestion, to ensure that surface antigen markers remained intact. Zonal unit-gravity
elutriation was used to enrich the TNC on the basis of their high sedimentation rate,
followed by immunomagnetic bead depletion to remove residual mononuclear cell
contaminants and a density separation to remove debris. The TNC-L were then released
from inside TNC by a short period of culture. The measured contamination of TNC-L
with exogenous thymocytes was around 0.5%. Three-color immunofluorescent labeling
revealed that TNC-L included, as well as a maiority of immature CD4+8+3low thymocytes,
about 12% of apparently mature CD4+8-3high and CD4-8+3high thymocytes. TNC are
located in the cortex, where mature cells are rare; the occurrence of mature phenotype
cells within these structures suggests that they represent a microenvironment for the
selection and generation of mature T cells. 相似文献
95.
Green Steven; Fishel Simon; Hall Jenny; Hunter Alison; Fleming Steven; Hobson Geoffrey; Roe Heather; Dowell Ken; Thornton Simon; Klentzeris Lucas 《Human reproduction (Oxford, England)》1995,10(6):1430-1434
Utilizing real-time computer image analysis, individual spermatozoawere selected using microaspiration. Selection criteria werebased on potential hyperactivation motility characteristics;the amplitude of lateral head displacement >7.5 µm,curvilinear velocity >70 µm/s and linearity of <30%.For this pilot study, 16 patients (eight in each group) wererecruited. Using subzonal insemination (SUZI), up to five (mean= 4.4 ± 0.3) spermatozoa selected using computer-imagesperm selection (CISS) were microinjected, or up to 15 (mean= 12.8 ± 1.3 SD) unselected spermatozoa. In the groupwhich utilized CISS, 28 out of 49 (57%) oocytes were fertilizedcompared with 13 out of 52 (25%) utilizing conventional SUZI(P < 0.04); polyspermy was 20% (n = 10) and 2% (n = 1) respectively.CISS with SUZI showed increased efficiency in achieving fertilizationand is a novel approach to studying individual sperm functionin a sperm egg bioassay where gamete ratios are close to unity. 相似文献
96.
Kei Matsuzaki Ken Ishihara Yoshinao Shinohara Taiichi Kanai 《Macromolecular chemistry and physics.》1986,187(9):2199-2208
Oligostyryllithium was synthesized by the reaction of sec-butyllithium with styrene in diethyl ether at ?40°C. Dimer model anions (counter cations: Li and K) of the growing chain ends were synthesized by metallation of 1-methoxy-1,3-diphenylpropane. The structures of the lithium compounds were corroborated by 13C NMR spectroscopy and compared with those of the potassium compounds. As for polystyryllithium and its model compounds, the charge density on the α-carbon increased and that on the phenyl ring of the growing end decreased with increasing molecular weight, while, in polystyrylpotassium and its model compounds, the charge density on the α-carbon increased and the one on the phenyl ring did not change with increasing molecular weight. The temperature change of the 1H NMR spectrum of oligostyryllithium in diethyl ether indicated rotation around the C-1? Cα bond at lower temperatures than in tetrahydrofuran, but the activation energy was the same in both solvents. T1 values of the phenyl carbons in model compound 2b were one to two orders of magnitude shorter than those of the protonated compound. 相似文献
97.
Ken Nakazawa 《Pflügers Archiv : European journal of physiology》1994,427(1-2):129-135
Modulation by protein phosphorylation of the relation between acetylcholine (ACh)-activated current (I
ACh) and adenosine triphosphate-(ATP)-activated current (I
ATP) was investigated with the whole-cell voltage-clamp technique in rat sympathetic neurons. During simultaneous activation by 100 M ATP of an inward current, the current evoked by 100 M ACh was reduced to 60–70% of that in the absence of ATP. Effects of compounds that are known to modulate protein phosphorylation were tested by including them in the intracellular solution. The reduction ofI
ACh by ATP was not observed when K252a (1 M), a non-selective protein kinase inhibitor, adenosine 5-O-(3-thiotriphosphate) (ATP[S], 1 mM) or,-methylene ATP (1 mM) were included in the intracellular solution. Activators of protein kinases, adenosine 3,5-cyclic monophosphate (cAMP, 100 M), guanosine 3,5-cyclic monophosphate (cGMP, 100 M), phorbol 12-myristate 13-acetate (PMA, 1 M), also abolished the reduction by ATP ofI
ACh. The effects of okadaic acid, a protein phosphatase inhibitor, were paradoxical: okadaic acid (2 M) itself abolished the reduction by ATP ofI
ACh but it antagonized the abolishment by cAMP or cGMP of the reduction ofI
ACh. Okadaic acid did not affect the disappearance of the reduction ofI
ACh by ATP in the presence of intracellular PMA. The results suggest that the interaction betweenI
ACh andI
ATP is regulated by protein phosphorylation/dephosphorylation. Possible mechanisms underlying the effects of these modulators of protein phosphorylation are discussed. 相似文献
98.
99.
The etiology and pathogenesis of inflammatory bowel disease are up to now still not clear and definite. Establishing the ideal animal model to study its cause and pathogenesis of this disease is very important. The ideal animal model should have the same manifestation with human inflammatory bowel disease on clinical and pathologic feature etc. In this article, the method, the pathologic character isfics and concerning pathogenesis, of a few common useful experiment animal models are discussed. 相似文献
100.
Baldwin T Henri S Curtis J O'Keeffe M Vremec D Shortman K Handman E 《Infection and immunity》2004,72(4):1991-2001
Using a metacyclic promastigote ear infection model of cutaneous leishmaniasis, we examined the phenotype, parasite load, and cytokine production of dendritic cells in the skin and draining lymph nodes of resistant C57BL/6J and susceptible BALB/c mice. Five dendritic cell populations were isolated from the skin and lymph nodes, and the main difference between the groups of mice was an increased number of plasmacytoid dendritic cells in the lymph nodes of the susceptible mice. Although similar cell types were present in the skin emigrants of both strains, there was a 10-fold larger number of cells in BALB/c mouse skin early in infection than in C57BL/6J mouse skin. None of the dendritic cells in the lymph nodes harbored parasites until 3 weeks after infection, with the Langerhans cells having the largest load and the plasmacytoid dendritic cells having the smallest load but the longest lasting infection. Although parasites could be detected in the lymph nodes a few hours after infection, none of the skin emigrants harbored parasites, indicating that they are not the vehicle that ferries the parasites from the skin to the lymph nodes. The presence of larger numbers of plasmacytoid cells in infected BALB/c mice, the more protracted infection of these cells, and their production of alpha interferon point to a complex and important role for the plasmacytoid cells in leishmaniasis. 相似文献