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   59篇
  免费   2篇
  2013年   4篇
  2012年   1篇
  2011年   3篇
  2009年   1篇
  2008年   1篇
  2006年   2篇
  2005年   1篇
  2004年   4篇
  2003年   7篇
  2002年   4篇
  2000年   1篇
  1998年   1篇
  1997年   2篇
  1996年   3篇
  1995年   4篇
  1994年   3篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1988年   3篇
  1987年   3篇
  1986年   1篇
  1985年   2篇
  1984年   3篇
  1983年   1篇
  1975年   1篇
  1968年   1篇
排序方式: 共有61条查询结果,搜索用时 15 毫秒
31.
Immunohistochemistry has been used to demonstrate tyrosine hydroxylase (TH), dopamine--hydroxylase (DBH), phenylethanolamine N-methyltransferase (PNMT), neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) immunoreactivities, and acetylcholinesterase (AChE) activity was demonstrated in rat adrenal glands. The TH, DBH, NPY and VIP immunoreactivities and AChE activity were observed in both the large ganglion cells and the small chromaffin cells whereas PNMT immunoreactivity was found only in chromaffin cells, and not in ganglion cells. Most intraadrenal ganglion cells showed NPY immunoreactivity and a few were VIP immunoreactive. Numerous NPY-immunoreactive ganglion cells were also immunoreactive for TH and DBH; these cells were localized as single cells or groups of several cells in the adrenal cortex and medulla. Use of serial sections, or double and triple staining techniques, showed that all TH- and DBH-immunoreactive ganglion cells also showed NPY immunoreactivity, whereas some NPY-immunoreactive ganglion cells were TH and DBH immunonegative. NPY-immunoreactive ganglion cells showed no VIP immunoreactivity. AChE activity was seen in VIP-immunopositive and VIP-immunonegative ganglion cells. These results suggest that ganglion cells containing noradrenaline and NPY, or NPY only, or VIP and acetylcholine occur in the rat adrenal gland; they may project within the adrenal gland or to other target organs. TH, DBH, NPY, and VIP were colocalized in numerous immunoreactive nerve fibres, which were distributed in the superficial adrenal cortex, while TH-, DBH- and NPY-immunoreactive ganglion cells and nerve fibres were different from VIP-immunoreactive ganglion cells and nerve fibres in the medulla. This suggests that the immunoreactive nerve fibres in the superficial cortex may be mainly extrinsic in origin and may be different from those in the medulla.  相似文献   
32.
The immunohistochemical study revealed tyrosine hydroxylase (TH), dopamine -hydroxylase (DBH), phenylethanolamine N-methyltransferase (PNMT), serotonin, glutamate decarboxylase (GAD) and -aminobutyric acid (GABA) immunoreactivities in the mouse carotid body. TH and DBH immunoreactivities were found in almost all chief cells and a few ganglion cells, and in relatively numerous varicose nerve fibers of the carotid body. The histofluorescence microscopy showed catecholamine fluorescence in almost all chief cells. However, no PNMT immunoreactivity was observed in the carotid body. Serotonin, GAD and GABA immunoreactivities were also seen in almost all chief cells of the carotid body. From combined immunohistochemistry and fluorescence histochemistry, catecholamine and serotonin or catecholamine and GABA were colocalized in almost all chief cells. Thus, these findings suggest that noradrenaline, serotonin and GABA may be synthesized and co-exist in almost all chief cells of the mouse carotid body and may play roles in chemoreceptive functions.  相似文献   
33.
34.
Human scalp hair and some kinds of vegetable and animal fibers were analyzed by means of the SR excited X-ray fluorescence method (SRXFA) and the neutron activation method (NAA). Human hair samples collected from five males and five females were washed by the IAEA method prior to analysis. In the SRXFA analysis, samples were excited by monochromated X-rays. Fluorescence X-rays were measured by an Si(Li) detector. The elements detected in all hair samples were S, Ca, Cu, Fe, Zn, Br, and Sr. The elements K, Ti, Cr, Mn, Ni, Se, Hg, and Pb were also detected in several samples. After SRXFA analysis these same samples were analyzed by the NAA method. Elements such as Cu, Zn, and Br were detected by both methods, and their relative concentrations show a good agreement of variation between individuals. However, Pb was only detected by SRXFA, and Na, Au, and Sb were only detected by NAA. Therefore, these two methods are complementary to each other for trace element analysis.  相似文献   
35.
Glycoconjugates reacting with eel anti-H agglutinin were purified from extracts of leaves of three species of cruciferous plants (radish, turnip, and rape) by precipitation with ethanol, ion-exchange chromatography, and gel filtration. High voltage paper electrophoresis or ultracentrifugal analysis revealed that the purified specimens were homogeneous. Their apparent molecular weights were estimated to range from 0.5 to 1.5 x 105. They consisted of a novel l-fucose-containing acidic arabinogalactan-protein composed of residues of l-arabinose, d-galactose, l-fucose, 4-O-methyl-d-glucuronic acid, and d-glucuronic acid in similar molar proportions, and containing polypeptide portions with abundant hydroxyproline, serine, threonine, and alanine. All the arabinogalactan-proteins exhibited potent inhibitory activity against the hemagglutination of human O erythrocytes by eel anti-H agglutinin.  相似文献   
36.
Radiation exposure induces acute myeloid leukemia (AML) in humans and mice. Recent studies postulated that AML stem cells of spontaneous human AML arise from hematopoietic stem cells. However, other studies support the possibility that short-lived committed progenitors transform into AML stem cells, accompanied by a particular gene mutation. It remains unclear whether AML stem cells are present in radiation-induced AML, and information regarding AML-initiating cells is lacking. In this study, we identified and analyzed AML stem cells of mice with radiation-induced AML. The AML stem cells were identified by transplanting 100 bone marrow cells from mice with radiation-induced AML. We injected 100 cells of each of seven cell populations corresponding to different stages of hematopoietic cell differentiation and compared the latencies of AMLs induced in recipient mice. The identified radiation-induced AML stem cells frequently displayed similarities in both CD antigen and gene expression profiles with normal common myeloid progenitors. The number of common myeloid progenitor-like AML stem cells was significantly increased in mice with radiation-induced AML, but the progeny of common myeloid progenitors was decreased. In addition, analysis of radiation effects on the hematopoietic system showed that common myeloid progenitor cells were extremely radiosensitive and that their numbers remained at low levels for more than 2?months after radiation exposure. Our results suggest that murine radiation-induced AML stem cells arise from radiosensitive cells at a common myeloid progenitor stage.  相似文献   
37.
The thread cells in the slime gland of Japanese hagfishes, Paramyxine atami and Eptatretus burgeri were studied by light and electron microscopy. The mature thread cells are large elements (180 times 80 mu) filled with an intricately coiled thread, approximately 2 mu in diameter. The protein nature of the thread has been confirmed by histochemical examination. In the initial stage of growth, the thread consists of a bundle of distinctly parallel filaments approximately 90-120 A in diameter and a centrally located tubular component approximately 230-260 A in diameter which occurs singly or occasionally as a double and triple structure. The developing thread displays thin filaments, approximately 30-60 A in diameter. The thin filaments are composed of fine fibrous structures, subfilaments, approximately 10-30 A in diameter. On the outer surface of the thread a coating is apparent, giving it a fluffy appearance. Polysomal clusters consisting of five or six ribosomes are predominant. Fine fibrous structures are also found among the threads; they seem to have a spatial relationship with the polysomes and resemble the subfilament constituents of the thin filaments. From these results, it may be suggested that the fine fibrous structures synthesized by polysomes, twist together and coalesce into a thread. The problem of the polysome size and the molecular weight of the fibrous protein synthesized is discussed.  相似文献   
38.
The primary targets for SARS-CoV infection are the epithelial cells in the respiratory and intestinal tract. The angiotensin-converting enzyme 2 (ACE-2) has been identified as a functional receptor for SARS-CoV. ACE-2 has been shown to be expressed at the apical domain of polarized Calu-3 cells. In this report, interferon alfacon 1 was examined for inhibitory activities against SARS-CoV on human lung carcinoma epithelial Calu-3 cell line and the other three African green monkey kidney epithelial cell lines. Interferon alfacon 1 demonstrated significant antiviral activity in neutral red uptake assay and virus yield reduction assay. The data might provide an important insight into the mechanism of pathogenesis of SARS-CoV allowing further development of antiviral therapies for treating SARS infections.  相似文献   
39.
A simple membrane dialysis bioreactor was developed for a large-scale axenic culture of Symbiobacterium thermophilum, a symbiotic thermophile that requires co-cultivation with an associating thermophilic Bacillus strain S for normal growth. The bioreactor consisted of an outer- and an inner-coaxial cylindrical compartment bordered across a dialyzing membrane, which enabled a 1 l-scale dialysis culture with exchange of low molecular metabolites between the two compartments to be performed. Using the bioreactor, growth characteristics of S. thermophilum and Bacillus strain S were assessed under two medium conditions. The growth of S. thermophilum was measured by quantitative PCR because the bacterium formed no visible colonies and gave abnormally low turbidity. In medium containing 2% tryptone peptone, S. thermophilum proliferated up to 4x10(7) cells/ml, and strict dependence on the co-culture with Bacillus strain S was observed. On the other hand, medium containing 0.5% yeast extract not only facilitated the growth of S. thermophilum in the co-culture (6x10(7) cells/ml), but also allowed limited pure growth independent of Bacillus strain S (1x10(7) cells/ml), implying that some component of yeast extract can partially replace the growth requirement of S. thermophilum supplied by Bacillus strain S. Both the oxidative redox potential values and the cell morphology in the independently growing culture suggested the occurrence of marked unbalanced growth possibly caused by significant metabolic changes. The bioreactor is applicable to the analyses of culturing characteristics in symbiotic systems between free-living microorganisms.  相似文献   
40.
Besides IgE, the Ab isotype that gives rise to sensitization and allergic asthma, the immune response to common inhalant allergens also includes IgG. Increased serum titers of allergen-specific IgG, induced spontaneously or by allergen vaccination, have been implicated in protection against asthma. To verify the interference of topical IgG with the allergen-triggered eosinophilic airway inflammation that underlies asthma, sensitized mice were treated by intranasal instillation of specific IgG, followed by allergen challenge. This treatment strongly reduced eosinophilic inflammation and goblet cell metaplasia, and increased Th1 reactivity and IFN-gamma levels in bronchoalveolar lavage fluid. In contrast, inflammatory responses were unaffected in IFN-gamma-deficient mice or when applying F(ab')(2). Although dependent on specific allergen-IgG interaction, inflammation triggered by bystander allergens was similarly repressed. Perseverance of inflammation repression, apparent after secondary allergen challenge, and increased allergen capture by alveolar macrophages further characterized the consequences of topical IgG application. These results assign a novel protective function to anti-allergen IgG namely at the local level interference with the inflammatory cascade, resulting in repression of allergic inflammation through an FcgammaR- and IFN-gamma-dependent mechanism. Furthermore, these results provide a basis for topical immunotherapy of asthma by direct delivery of anti-allergen IgG to the airways.  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