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排序方式: 共有125条查询结果,搜索用时 15 毫秒
91.
Prenatal compensatory renal growth: documentation with US 总被引:3,自引:0,他引:3
92.
在妊娠的不同时期,胎盘中黄体生成素释放激素(LHRH)的含量不同。离体培养的绒毛组织实验也发现,相同剂量的外源性LHRH对妊娠中期和终末期胎盘绒毛组织分泌hCG和孕酮作用强度也不同。本实验室曾发现,LHRH类似物(LHRH-A)对体外培养孕早期(10~12周)和孕终末期(38~40周)绒毛组织分泌hCG均有兴奋作用,但对分泌孕酮的作用不同,即LHRH-A对早孕绒毛分泌孕酮有抑制作用,而对终末期分泌孕酮 相似文献
93.
Bilateral activation of fronto-parietal networks by incrementing demand in a working memory task 总被引:7,自引:3,他引:4
Working memory (WM) is known to activate the prefrontal cortex. In the
present study we hypothesized that when additional contingencies are added
to the instruction of a WM task, this would increase the WM load and result
in the activation of additional prefrontal areas. With positron emission
tomography we measured regional cerebral blood flow in nine subjects
performing a control task and two delayed matching to sample tasks, in
which the subjects were matching colours and patterns to a reference
picture. The second of the two delayed matching tasks had a more complex
instruction than the first, with additional contingencies of how to
alternate between the matching of colours and patterns. This task thus
required the subjects not only to remember a stimulus to match but also to
perform this matching according to a specified plan. Both delayed matching
tasks activated cortical fields in the middle frontal gyrus, the frontal
operculum, upper cingulate gyrus, inferior parietal cortex and cortex
lining the intraparietal sulcus, all in the left hemisphere. When
alternated delayed matching was compared to simple delayed matching,
increases were located in the right superior and middle frontal gyrus and
the right anterior inferior parietal cortex. The increased demand during
alternated matching thus resulted in bilateral activation of both
dorsolateral prefrontal and inferior parietal cortex. The area in the
inferior parietal cortex has previously been coactivated with the
dorsolateral prefrontal cortex in several WM tasks, irrespective of the
sensory modality of the stimuli, and during tasks involving planning.
相似文献
94.
AJ McNeish BT Roux S-B Aylett AM Van Den Brink GS Cottrell 《British journal of pharmacology》2012,167(8):1679-1690
Background and Purpose
Calcitonin gene-related peptide (CGRP) is a potent vasodilator, implicated in the pathogenesis of migraine. CGRP activates a receptor complex comprising, calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 1 (RAMP1). In vitro studies indicate recycling of CLR•RAMP1 is regulated by degradation of CGRP in early endosomes by endothelin-converting enzyme-1 (ECE-1). However, it is not known if ECE-1 regulates the resensitization of CGRP-induced responses in functional arterial tissue.Experimental Approach
CLR, ECE-1a-d and RAMP1 expression in rat mesenteric artery smooth muscle cells (RMA-SMCs) and mesenteric arteries was analysed by RT-PCR and by immunofluorescence and confocal microscopy. CGRP-induced signalling in cells was examined by measuring cAMP production and ERK activation. CGRP-induced relaxation of arteries was measured by isometric wire myography. ECE-1 was inhibited using the specific inhibitor, SM-19712.Key Results
RMA-SMCs and arteries contained mRNA for CLR, ECE-1a-d and RAMP1. ECE-1 was present in early endosomes of RMA-SMCs and in the smooth muscle layer of arteries. CGRP induced endothelium-independent relaxation of arteries. ECE-1 inhibition had no effect on initial CGRP-induced responses but reduced cAMP generation in RMA-SMCs and vasodilation in mesenteric arteries responses to subsequent CGRP challenges.Conclusions And Implications
ECE-1 regulated the resensitization of responses to CGRP in RMA-SMCs and mesenteric arteries. CGRP-induced relaxation did not involve endothelium-derived pathways. This is the first report of ECE-1 regulating CGRP responses in SMCs and arteries. ECE-1 inhibitors may attenuate an important vasodilatory pathway, implicated in primary headaches and may represent a new therapeutic approach for the treatment of migraine. 相似文献95.
96.
97.
Superior vena cava syndrome associated with massive thrombosis: treatment with expandable wire stents 总被引:3,自引:0,他引:3
Two patients with superior vena cava syndrome (SVCS) associated with massive thrombosis were treated by means of local thrombolytic therapy and placement of modified Gianturco expandable wire stents. Treatment resulted in complete resolution of the SVCS symptoms. The combination of local thrombolytic therapy and stent placement allows a more aggressive approach to treatment of SVCS and provides longer-term palliation of symptoms even for patients with later stages of the disease. 相似文献
98.
Noncoronary angioplasty 总被引:9,自引:0,他引:9
99.
Measurement of benzene oxide in the blood of rats following administration of benzene 总被引:2,自引:1,他引:2
Lindstrom AB; Yeowell-O'Connell K; Waidyanatha S; Golding BT; Tornero-Velez R; Rappaport SM 《Carcinogenesis》1997,18(8):1637-1641
Although it is generally assumed that metabolism of benzene proceeds
through an initial step involving oxidation to benzene oxide (BO) by CYP450
in the liver, the production of BO has never been unambiguously confirmed
in animals dosed with benzene. Furthermore, prevailing hypotheses of the
mechanism by which benzene causes cancer have ignored the possibility that
BO might play a direct role, despite the fact that BO is electrophilic,
binds covalently to cell macromolecules and is presumably genotoxic. A
likely reason for this lack of attention to the role of BO in the
carcinogenesis of benzene is the presumption that this epoxide is too
reactive to escape the hepatocyte after it is formed. We employed gas
chromatography-mass spectrometry to measure BO in the blood of F344 rats,
both in vitro and up to 24 h following oral administration of benzene.
Surprisingly, BO was relatively stable in rat blood at 37 degrees C
(estimated half-life = 7.9 min) and, after administering a single dosage of
400 mg benzene/kg body wt, a blood concentration of 90 nM BO (8.5 ng/ml)
was measured for approximately 9 h. Using a published PBPK model we
estimate that approximately 4.3% of the metabolized dose of benzene was
released as BO from the liver into blood. This confirms that BO is, indeed,
formed from metabolism of benzene and is sufficiently stable to be
distributed throughout the body at levels which are likely to be greater
than those of the other electrophilic benzene metabolites.
相似文献
100.
Studies of percutaneous epididymal sperm aspiration (PESA) and intracytoplasmic sperm injection 总被引:3,自引:0,他引:3
Meniru GI; Gorgy A; Batha S; Clarke RJ; Podsiadly BT; Craft IL 《Human reproduction update》1998,4(1):57-71
Four distinct studies were carried out using two data sets ofpercutaneous epididymal sperm aspiration (PESA) and intracytoplasmicsperm injection (ICSI) procedures performed from March 1993to January 1997. In study A, an analysis of 181 ICSI treatmentcycles following PESA revealed a successful epididymal spermretrieval rate of 83%. It confirmed that PESA is an effectivesperm retrieval method and the associated ICSI pregnancy rate(35% per embryo transfer) compared favourably with that of othersperm retrieval methods. In study B, the relevance of a priordiagnostic PESA procedure was ascertained by comparing the spermretrieval rates in two groups of patients having their firstICSI treatment cycle with spermatozoa retrieved through PESA.Group B1 (n=50) had diagnostic PESA prior to the ICSI treatmentcycle PESA procedure, unlike patients in group B2 (n=64) whodid not. The sperm retrieval rate in the treatment cycle procedurewas not different at 90 and 82.8% for groups B1 and B2 respectively.However, the discontinuation of diagnostic PESA is fraught withproblems including liability to medico-legal sanctions. In studyC, analysis of 177 treatment cycles involving PESA and ICSIrevealed a successful sperm retrieval rate by PESA of 82% inthe first cycle, 93% in the second, 96% in the third and 100%in the fourth cycle. The same trend was evident when sperm retrievalwas examined in relation to each of the epididymides. Retrievedspermatozoa were found to be motile in 67-100% of cases andthe frequency of samples containing motile spermatozoa did notdecrease with increase in the number of PESA attempts. Theseresults show that PESA does not jeopardize future epididymalsperm retrieval. In study D, the outcome of treatment with ICSIusing ejaculated spermatozoa (305 cycles) (group D1) was comparedwith that of ICSI using spermatozoa obtained through PESA (54cycles) (group D2). The median age of women in the two groupsof couples was similar (34 years). In group D1, 70% of metaphaseII oocytes were fertilized compared with 61% in group D2 (P<0.01).The cleavage rate and the median numbers of transferred andcryopreserved embryos were similar in both groups. There wasno significant difference between the clinical pregnancy rates(33 and 42% in groups D1 and D2 respectively). Our results showthat the outcome of PESA-ICSI treatment compared favourablywith that of ICSI using ejaculated spermatozoa. 相似文献