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排序方式: 共有9059条查询结果,搜索用时 656 毫秒
51.
Wilson Watanabe Tomoyuki Kurumada Takayuki Shirai Yutaka Tsutsumi 《Pathology international》1995,45(11):895-900
A rare insulin-immunoreactive neuroendocrine tumor of the duodenum in a 54 year old male is reported. The incidentally identified tumor was located on the anterior free wall of the duodenal bulb and measured approximately 6 mm in diameter. Uncomplicated endoscopic resection of the tumor was carried out. The lesion exhibited classic histologic features of insulinoma of the β-islet cell type with stromal amyloid deposition. In addition to positive reactivities of chromogranin A, neuron-specific enolase, synaptophysin, Leu 7 (CD57), cystatin C, CA15–3 and cytokeratin, the non-argyrophilic tumor cells were strongly immunoreactive for insulin and C-peptide. The stromal amyloid was clearly labeled for amylin. A few cells were stained for somato-statin, whereas other hormones were negative. Interestingly, a few isolated insulin-positive cells were identiii in the non-neoplastic duodenal mucosa in the proximity of the tumor. lmmunoelectron microscopy using paraffin sections disclosed insulin-immunoreactive secretory granules in the cytoplasm. The patient exhibited no signs or symptoms of hypoglycemia. Serum insulin levels were not measured prior to resection. No tumors were demonstrated in the pancreas. Magnetic resonance imaging revealed a 1 cm asymptomatic pituitary mass, in association with moderately elevated serum prolactin levels. The patient is currently being followed up in the outpatient clinic. 相似文献
52.
53.
Kozue Kaibara Takashi Akasu Takayuki Tokimasa Kyozo Koketsu 《Pflügers Archiv : European journal of physiology》1985,405(1):24-28
Adrenaline markedly increased the ouabain-sensitive 22Na+-efflux by stimulating the Na+-K+ pump in frog skeletal muscle. The facilitatory effects of adrenaline had the following properties. The effects of adrenaline on the ouabain-sensitive Na+-efflux were observed at concentrations greater than 0.1 microM and the magnitude increased with concentration up to 10 microM. At a concentration of 30 microM, adrenaline markedly augmented the ouabain-sensitive Na+-efflux, but other biogenic amines were less effective (noradrenaline and dopamine) or ineffective (histamine and serotonin). The increase of Na+-efflux induced by 1 microM adrenaline was blocked by 3 microM propranolol, but not by 3 microM phenoxybenzamine. The properties of the facilitatory action of adrenaline on the ouabain-sensitive Na+-efflux suggest that beta-adrenoceptors have an important role in modulating the Na+-K+ pump activity in the skeletal muscle membrane. The protein complex localized in excitable membranes, namely the Na+-K+ ATPase-beta-adrenoceptor complex, may be the functional unit which operates the membrane machinery driving the Na+-K+ pump. 相似文献
54.
Fibrinogen stabilizes placental-maternal attachment during embryonic development in the mouse 总被引:9,自引:0,他引:9
Iwaki T Sandoval-Cooper MJ Paiva M Kobayashi T Ploplis VA Castellino FJ 《The American journal of pathology》2002,160(3):1021-1034
In humans, maternal fibrinogen (Fg) is required to support pregnancies by maintaining hemostatic balance and stabilizing uteroplacental attachment at the fibrinoid layer found at the fetal-maternal junction. To examine relationships between low Fg levels and early fetal loss, a genetic model of afibrinogenemia was developed. Pregnant mice homozygous for a deletion of the Fg-gamma chain, which results in a total Fg deficiency state (FG(-/-)), aborted the fetuses at the equivalent gestational stage seen in humans. Results obtained from timed matings of FG(-/-) mice showed that vaginal bleeding was initiated as early as embryonic day (E)6 to 7, a critical stage for maternal-fetal vascular development. The condition of afibrinogenemia retarded embryo-placental development, and consistently led to abortion and maternal death at E9.75. Lack of Fg did not alter the extent or distribution pattern of other putative factors of embryo-placental attachment, including laminin, fibronectin, and Factor XIII, indicating that the presence of fibrin(ogen) is required to confer sufficient stability at the placental-decidual interface. The results of these studies demonstrate that maternal Fg plays a critical role in maintenance of pregnancy in mice, both by supporting proper development of fetal-maternal vascular communication and stabilization of embryo implantation. 相似文献
55.
Masuda S Sakagami T Hirota S 《Shinrigaku kenkyu : The Japanese journal of psychology》2002,73(1):34-41
Ellsberg's two-color problem, known as an example of ambiguity aversion, has generated a great deal of interest among many researchers. However, an unsettled question remains regarding the conditions that lead to heightened or diminished ambiguity aversion. We conducted a series of experiments, which required participants to choose between a clear and vague bet. Results showed that participants did not always prefer the clear bet, and the ratios of those who indicated ambiguity aversion varied depending on the types of ambiguity. Furthermore, ambiguity aversion consistently decreased when participants were allowed to choose the ambiguity task they would perform. These results were interpreted in terms of the pattern of second order probability distributions and illusion of control. 相似文献
56.
Nobuyuki Mochizuki Norio TakagiKoji Kurokawa Takayuki KawaiShintaro Besshoh Kouichi TanonakaSatoshi Takeo 《Neuroscience letters》2007
The N-methyl-D-aspartate (NMDA) receptor, a subtype of ionotropic glutamate receptors, plays an important role in the regulation of neuronal development, learning and memory, and neurodegenerative diseases. NMDA receptor blockade enhances neurogenesis in the hippocampal dentate gyrus in vivo. The effect of NMDA receptor antagonist on proliferation of neural progenitor cells, however, remains to be determined. We investigated changes in the diameter and number of neurospheres derived from the embryonic rat brain after NMDA receptor blockade. Cortical progenitor cells were isolated from gestational day 18 fetal rats according to the Percoll density gradient method. Cultured spheres expressed neural progenitor markers, musashi-1 and nestin. Immunohistochemical analysis demonstrated that cells in Dulbecco's modified Eagle medium/F12 containing 1% fetal bovine serum on day 8 differentiated to MAP-2-positive neurons and GFAP-positive astrocytes. The expression of NR1 and NR2B subunits of the NMDA receptor in neurospheres was detected. Neither brief nor sustained exposure to NMDA altered the diameter and number of neurospheres. Brief exposure to 30 μM MK-801, an NMDA receptor antagonist, decreased the diameter of neurospheres. Sustained exposure to 30 μM MK-801 decreased the diameter and number of neurospheres. Our results provide evidence that MK-801 directly decreased proliferation of neural progenitor cells. 相似文献
57.
Jyoti V. Chauthaiwale Takayuki Sakai Samuel E. Taylor Indu S. Ambudkar 《Pflügers Archiv : European journal of physiology》1996,432(1):105-111
The molecular mechanism(s) involved in mediating Ca2+ entry into rat parotid acinar and other non-excitable cells is not known. In this study we have examined the kinetics of
Ca2+ entry in fura-2-loaded parotid acinar cells, which were treated with thapsigargin to deplete internal Ca2+ pools (Ca2+-pool-depleted cells). The rate of Ca2+ entry was determined by measuring the initial increase in free cytosolic [Ca2+] ([Ca2+]i) in Ca2+-pool-depleted, and control (untreated), cells upon addition of various [Ca2+] to the medium. In untreated cells, a low-affinity component was detected with K
Ca = 3.4 ± 0.7 mM (where K
Ca denotes affinity for Ca2+) and V
max = 9.8 ± 0.4 nM [Ca2+]i /s. In thapsigargin-treated cells, two Ca2+ influx components were detected with K
Ca values of 152 ± 79 μM (V
max = 5.1 ± 1.9 nM [Ca2+]i/s) and 2.4 ± 0.9 mM (V
max = 37.6 ± 13.6 nM [Ca2+]i/s), respectively. We have also examined the effect of Ca2+ and depolarization on these two putative Ca2+ influx components. When cells were treated with thapsigargin in a Ca2+-free medium, Ca2+ influx was higher than into cells treated in a Ca2+-containing medium and, while there was a 46% increase in the V
max of the low-affinity component (no change in K
Ca), the high-affinity component was not clearly detected. In depolarized Ca2+-pool-depleted cells (with 50 mM KCl in the medium) the high-affinity component was considerably decreased while there was
an apparent increase in the K
Ca of the low-affinity component, without any change in the V
max. These results demonstrate that Ca2+ influx into parotid acinar cells (1) is increased (four- to five-fold) upon internal Ca2+ pool depletion, and (2) is mediated via at least two components, with low and high affinities for Ca2+.
Received: 30 October 1995/Received after revisionand accepted: 13 December 1995 相似文献
58.
Fukao T Yamada T Tanabe M Terauchi Y Ota T Takayama T Asano T Takeuchi T Kadowaki T Hata Ji J Koyasu S 《Nature immunology》2002,3(3):295-304
Mice that lack the p85alpha regulatory subunit of phosphatidylinositol-3 kinase (PI3K) are deficient in gastrointestinal and peritoneal mast cells but have dermal mast cells. Accordingly, these mice show impaired bacterial clearance in response to acute septic peritonitis and are highly susceptible to infection by the intestinal nematode Strongyloides venezuelensis. Systemic anaphylactic shock responses, however, are intact. We found that although reconstitution of PI3Kminus sign/minus sign mice with bone marrow--derived mast cells (BMMCs) restored anti-bacterial immunity, only T helper type 2 (TH2)-conditioned BMMCs, not "standard" BMMCs, were able to restore anti-nematode immunity. This finding highlights the importance of the TH2 response in the control of nematode infection. Thus, PI3K likely plays an essential role in host immune responses by regulating both the development and induction of mast cells. 相似文献
59.
Role of ubiquitin carboxy terminal hydrolase-L1 in neural cell apoptosis induced by ischemic retinal injury in vivo 总被引:7,自引:0,他引:7 下载免费PDF全文
Harada T Harada C Wang YL Osaka H Amanai K Tanaka K Takizawa S Setsuie R Sakurai M Sato Y Noda M Wada K 《The American journal of pathology》2004,164(1):59-64
Ubiquitin is thought to be a stress protein that plays an important role in protecting cells under stress conditions; however, its precise role is unclear. Ubiquitin expression level is controlled by the balance of ubiquitinating and deubiquitinating enzymes. To investigate the function of deubiquitinating enzymes on ischemia-induced neural cell apoptosis in vivo, we analyzed gracile axonal dystrophy (gad) mice with an exon deletion for ubiquitin carboxy terminal hydrolase-L1 (UCH-L1), a neuron-specific deubiquitinating enzyme. In wild-type mouse retina, light stimuli and ischemic retinal injury induced strong ubiquitin expression in the inner retina, and its expression pattern was similar to that of UCH-L1. On the other hand, gad mice showed reduced ubiquitin induction after light stimuli and ischemia, whereas expression levels of antiapoptotic (Bcl-2 and XIAP) and prosurvival (brain-derived neurotrophic factor) proteins that are normally degraded by an ubiquitin-proteasome pathway were significantly higher. Consistently, ischemia-induced caspase activity and neural cell apoptosis were suppressed approximately 70% in gad mice. These results demonstrate that UCH-L1 is involved in ubiquitin expression after stress stimuli, but excessive ubiquitin induction following ischemic injury may rather lead to neural cell apoptosis in vivo. 相似文献
60.
The development and distribution of lymphocyte subsets in bovine gut-associated lymphoid tissues (ileal and jejunal Peyer's patches (PP)) were examined. Before birth, the composition of lymphocyte subsets in both PP follicles did not differ except for the dimensions of the interfollicular area and the dome region. Many IgM+ cells were observed in these follicles, but very few CD3+, IgG+, and IgA+ cells could be found. At neonatal period, the IgG+ cells, which did not produce IgG mRNA, were dominant within both PP follicles. From 1 month after birth, many CD3+ cells, IgG mRNA expression, and IgA mRNA expression were detected within the jejunal PP follicles, but very few were in the ileal PP follicles. These data suggest that the characteristics of the jejunal PP follicles metamorphose into secondary lymphoid tissue such as germinal centers at around 1 month after birth, whereas the characteristics of ileal PP follicles were distinct from those of germinal centers. 相似文献