首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   90篇
  免费   8篇
  2022年   1篇
  2021年   1篇
  2020年   1篇
  2018年   2篇
  2017年   4篇
  2016年   1篇
  2015年   5篇
  2014年   3篇
  2013年   5篇
  2012年   7篇
  2011年   6篇
  2010年   1篇
  2009年   2篇
  2008年   6篇
  2007年   4篇
  2006年   4篇
  2005年   3篇
  2004年   8篇
  2003年   9篇
  2002年   2篇
  2000年   1篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1994年   3篇
  1988年   1篇
  1986年   1篇
  1985年   2篇
  1983年   1篇
  1979年   1篇
  1978年   1篇
  1974年   3篇
  1973年   2篇
  1969年   2篇
  1967年   2篇
排序方式: 共有98条查询结果,搜索用时 31 毫秒
1.
Phencyclidine (PCP) receptors were successfully solubilized from rat forebrain membranes with 1% sodium cholate. Approximately 58% of the initial protein and 20-30% of the high-affinity PCP binding sites were solubilized. The high affinity toward PCP-like drugs, the stereo-selectivity of the sites, and the sensitivity to N-methyl-D-aspartate (NMDA) receptor ligands were preserved. Binding of the potent PCP receptor ligand N-[3H][1-(2-thienyl)cyclohexyl] piperidine ([3H]TCP) to the soluble receptors was saturable (KD = 35 nM), and PCP-like drugs inhibited [3H]TCP binding in a rank order of potency close to that observed for the membrane-bound receptors; the most potent inhibitors were TCP (Ki = 31 nM) and the anticonvulsant MK-801 (Ki = 50 nM). The NMDA receptor antagonist 2-amino-5-phosphonovaleric acid inhibited binding of [3H]TCP to the soluble receptors; glutamate or NMDA diminished this inhibition in a dose-dependent manner. Taken together, the results indicate that the soluble PCP receptor preparation contains the glutamate recognition sites and may represent a single receptor complex for PCP and NMDA, as suggested by electrophysiological data. The successful solubilization of the PCP receptors in an active binding form should now facilitate their purification.  相似文献   
2.
3.
OBJECTIVE--To evaluate the effectiveness and safety of endometrial laser ablation and transcervical resection of the endometrium compared with hysterectomy in the surgical treatment of women with dysfunctional uterine bleeding. DESIGN--Prospective randomised controlled trial. SETTING--Gynaecology department of a large teaching hospital. SUBJECTS--204 women who would otherwise have been undergoing hysterectomy for menorrhagia were recruited between August 1990 and March 1992 and randomly allocated to hysterectomy (n = 99) or conservative (hysteroscopic) surgery (transcervical resection (n = 52) and laser ablation (n = 53)). MAIN OUTCOME MEASURES--Operative complications, postoperative recovery, relief of menstrual and other symptoms, patient satisfaction with treatment after six and 12 months. RESULTS--Women treated by hysteroscopic surgery had less early morbidity and a significantly shorter recovery period than those treated by hysterectomy (median time to full recovery 2-4 weeks v 2-3 months, P < 0.001). Twelve months later 17 women in the hysteroscopy group had had a hysterectomy, 11 for continuing symptoms; 11 women had had a repeat hysteroscopic procedure; 45 were amenorrhoeic or had only a brown discharge; and 35 had light periods. Dysmenorrhoea and premenstrual symptoms improved in most women in both groups. After 12 months 89% (79/89) in the hysterectomy group and 78% (75/96) in the hysteroscopy group were very satisfied with the effect of surgery (P < 0.05); 95% (85/89) and 90% (86/96) thought that there had been an acceptable improvement in symptoms, and 72% (64/89) and 71% (68/96) would recommend the same operation to others. CONCLUSIONS--Hysteroscopic endometrial ablation was superior to hysterectomy in terms of operative complications and postoperative recovery. Satisfaction after hysterectomy was significantly higher, but between 70% and 90% of the women were satisfied with the outcome of hysteroscopic surgery. Hysteroscopic surgery can be recommended as an alternative to hysterectomy for dysfunctional uterine bleeding.  相似文献   
4.
OBJECTIVE: To compare in psychiatric and psychosocial terms the outcome of hysterectomy and endometrial ablation for the treatment of dysfunctional uterine bleeding. DESIGN: Prospective randomised controlled trial. SETTING--Obstetrics and gynaecology department of a large teaching hospital. SUBJECTS: 204 women with dysfunctional bleeding for whom hysterectomy would have been the preferred treatment were recruited over 24 months and randomly allocated to hysterectomy (99 women) or to hysteroscopic surgery (transcervical resection (52 women) or laser ablation (53 women). MAIN OUTCOME MEASURES: Mental state, martial relationship, psychosocial and sexual adjustment in assessments conducted before the operation and one month, six months, and 12 months later. RESULTS: Both treatments significantly reduced the anxiety and depression present before the operation, and there were no differences in mental health between the groups at 12 months. Hysterectomy did not lead to postoperative psychiatric illness. Sexual interest after the operation did not vary with treatment. Overall, 46 out of 185 (25%) women reported a loss sexual interest and 50 out of 185 (27%) reported increased sexual interest. Marital relationships were unaffected by surgery. Personality and duration of dysfunctional uterine bleeding played no significant part in determining outcome. CONCLUSIONS: Hysteroscopic surgery and hysterectomy have a similar effect on psychiatric and psychosocial outcomes. There is no evidence that hysterectomy leads to postoperative psychiatric illness.  相似文献   
5.
6.
NUP98-Hox fusion genes are newly identified oncogenes isolated in myeloid leukemias. Intriguingly, only Abd-B Hox genes have been reported as fusion partners, indicating that they may have unique overlapping leukemogenic properties. To address this hypothesis, we engineered novel NUP98 fusions with Hox genes not previously identified as fusion partners: the Abd-B-like gene HOXA10 and two Antennepedia-like genes, HOXB3 and HOXB4. Notably, NUP98-HOXA10 and NUP98-HOXB3 but not NUP98-HOXB4 induced leukemia in a murine transplant model, which is consistent with the reported leukemogenic potential ability of HOXA10 and HOXB3 but not HOXB4. Thus, the ability of Hox genes to induce leukemia as NUP98 fusion partners, although apparently redundant for Abd-B-like activity, is not restricted to this group, but rather is determined by the intrinsic leukemogenic potential of the Hox partner. We also show that the potent leukemogenic activity of Abd-B-like Hox genes is correlated with their strong ability to block hematopoietic differentiation. Conversely, coexpression of the Hox cofactor Meis1 alleviated the requirement of a strong intrinsic Hox-transforming potential to induce leukemia. Our results support a model in which many if not all Hox genes can be leukemogenic and point to striking functional overlap not previously appreciated, presumably reflecting common regulated pathways.  相似文献   
7.
OBJECTIVE: To evaluate the significance of histiocytes on normal cervical smears from postmenopausal women and correlate them with endometrial pathology. STUDY DESIGN: Histiocytes were classified into three types. The clinical history was obtained from cytologic and surgical reports. RESULTS: Among 108 cervical smears, 13 had large, foamy histiocytes (type A), 88 had histiocytes resembling superficial endometrial stromal cells (type B), and 7 had variably sized histiocytes alone or in association with inflammatory or multinucleated cells (type C). Endometrial pathology was identified in 13 patients (12.0%): 4/13 with type A histiocytes (2 endometrial adenocarcinomas, 2 endometrial polyps), 8/88 with type B histiocytes (8 endometrial polyps) and 1/7 with type C histiocytes (endometrial polyp). Among 70 patients with no clinical indications for endometrial sampling except for the presence of histiocytes, 4 demonstrated endometrial pathology (all endometrial polyps). In contrast, endometrial pathology was identified in 9/38 with clinical indications for endometrial sampling. Among the 13 patients with endometrial pathology, 9 had a significant clinical history (sensitivity of 69.2%), and 4 had histiocytes as the only indication for endometrial biopsy (sensitivity of 30.8%). CONCLUSION: A significant clinical history is more predictive of endometrial pathology and outweighs the significance of histiocytes as an indication for endometrial biopsy.  相似文献   
8.
Peroxidase activity in human saliva is composed of salivary peroxidase (80%), of salivary glandular origin, and myeloperoxidase (20%), of leukocyte origin. The term oral peroxidase (OPO) is used here to denote the total activity of both peroxidase species. Using the 2-nitrobenzoic acid-thiocyanate assay, OPO activity was measured in the saliva of nonsmokers after exposure to gas-phase cigarette smoke (CS) in an in vitro system using three puffs of CS in 1 h. A marked decrease of 76% of activity was observed following three puffs of CS. In order to elucidate the mechanism by which CS caused loss of OPO activity, several oxidants and antioxidants were applied to saliva in vitro in the presence and absence of CS. No protection for CS-induced loss of OPO activity occurred in the presence of glutathione, N-acetylcysteine, ascorbic acid, or Desferal. Exposure of saliva to purified aldehydes present in CS did not significantly affect OPO loss of activity. Similarly, ascorbic acid in the presence of FeCl(3) and nicotine also had no effect on OPO activity. Exposure of OPO to cyanate at levels present in CS caused a 65-70% loss of OPO activity, which was reversible after 24 h of dialysis. Moreover, hydroxocobalamin, a known cyanate chelator, could prevent CS- and potassium cyanide-induced inactivation of OPO by 70-90%. The results show that hydrogen cyanide, known to be present in microgram amounts per cigarette, is likely to be the species in CS responsible for loss of salivary OPO activity. The finding of reduced salivary OPO levels after CS exposure may represent a contributory mechanism for CS-related compromises in antimicrobial defenses in the aerodigestive tract.  相似文献   
9.
Accumulation of misfolded proteins as insoluble aggregates occurs in several neurodegenerative diseases. In Parkinson's disease (PD) and dementia with Lewy bodies (DLB), alpha-synuclein (alpha S) accumulates in insoluble inclusions. To identify soluble alpha S oligomers that precede insoluble aggregates, we probed the cytosols of mesencephalic neuronal (MES) cells, normal and alpha S-transgenic mouse brains, and normal, PD, and DLB human brains. All contained highly soluble oligomers of alpha S whose detection was enhanced by delipidation. Exposure of living MES neurons to polyunsaturated fatty acids (PUFAs) increased alpha S oligomer levels, whereas saturated FAs decreased them. PUFAs directly promoted oligomerization of recombinant alphaS. Transgenic mice accumulated soluble oligomers with age. PD and DLB brains had elevated amounts of the soluble, lipid-dependent oligomers. We conclude that alpha S interacts with PUFAs in vivo to promote the formation of highly soluble oligomers that precede the insoluble alpha S aggregates associated with neurodegeneration.  相似文献   
10.
The 3’end genomic region encodes a wide range of regulatory process including mRNA stability, 3’ end processing and translation. Here, we systematically investigate the sequence determinants of 3’ end mediated expression control by measuring the effect of 13,000 designed 3’ end sequence variants on constitutive expression levels in yeast. By including a high resolution scanning mutagenesis of more than 200 native 3’ end sequences in this designed set, we found that most mutations had only a mild effect on expression, and that the vast majority (~90%) of strongly effecting mutations localized to a single positive TA-rich element, similar to a previously described 3’ end processing efficiency element, and resulted in up to ten-fold decrease in expression. Measurements of 3’ UTR lengths revealed that these mutations result in mRNAs with aberrantly long 3’UTRs, confirming the role for this element in 3’ end processing. Interestingly, we found that other sequence elements that were previously described in the literature to be part of the polyadenylation signal had a minor effect on expression. We further characterize the sequence specificities of the TA-rich element using additional synthetic 3’ end sequences and show that its activity is sensitive to single base pair mutations and strongly depends on the A/T content of the surrounding sequences. Finally, using a computational model, we show that the strength of this element in native 3’ end sequences can explain some of their measured expression variability (R = 0.41). Together, our results emphasize the importance of efficient 3’ end processing for endogenous protein levels and contribute to an improved understanding of the sequence elements involved in this process.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号