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排序方式: 共有242条查询结果,搜索用时 15 毫秒
21.
Christopher Crane Noor Akhter Brandy W Johnson Mary Iruthayanathan Farhan Syed Akihiko Kudo Yi-Hong Zhou Gwen V Childs 《The journal of histochemistry and cytochemistry》2007,55(10):1059-1073
Leptin, a potent anorexigenic hormone, is found in the anterior pituitary (AP). The aim of this study was to determine whether and how pituitary leptin-bearing cells are regulated by nutritional status. Male rats showed 64% reductions in pituitary leptin mRNA 24 hr after fasting, accompanied by significant (30-50%) reductions in growth hormone (GH), prolactin, and luteinizing hormone (LH), and 70-80% reductions in target cells for gonadotropin-releasing hormone or growth hormone-releasing hormone. There was a 2-fold increase in corticotropes. Subsets (22%) of pituitary cells coexpressed leptin and GH, and <5% coexpressed leptin and LH, prolactin, thyroid-stimulating hormone, or adrenocorticotropic hormone. Fasting resulted in significant (55-75%) losses in cells with leptin proteins or mRNA, and GH or LH. To determine whether restoration of serum glucose could rescue leptin, LH, and GH, additional fasted rats were given 10% glucose water for 24 hr. Restoring serum glucose in fasted rats resulted in pituitary cell populations with normal levels of leptin and GH and LH cells. Similarly, LH and GH cells were restored in vitro after populations from fasted rats were treated for as little as 1 hr in 10-100 pg/ml leptin. These correlative changes in pituitary leptin, LH, and GH, coupled with leptin's rapid restoration of GH and LH in vitro, suggest that pituitary leptin may signal nutritional changes. Collectively, the findings suggest that pituitary leptin expression could be coupled to glucose sensors like glucokinase to facilitate rapid responses by the neuroendocrine system to nutritional cues. 相似文献
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23.
Treatment of viral and neoplastic diseases with double-stranded RNA derivatives and other new agents 总被引:1,自引:0,他引:1
Ambrus JL Chadha KC Islam A Akhter S Ambrus JL 《Experimental biology and medicine (Maywood, N.J.)》2006,231(8):1283-1286
Many attempts have been made to inhibit viral and neoplastic diseases by targeting the RNA system. The pathophysiologic significance of the microRNA system and the therapeutic potential of its manipulation are discussed. Studies of double-stranded RNA derivatives are reviewed. The therapeutic potential of one of these compounds, polyI:MPC, is emphasized. Studies of other related antiviral and antineoplastic agents are discussed, including 2'-deoxyoligocytidilates and telomerase inhibitors. 相似文献
24.
Nuruzzaman M Sharoni AM Satoh K Al-Shammari T Shimizu T Sasaya T Omura T Kikuchi S 《Biochemical and biophysical research communications》2012,423(2):417-423
Thioredoxin (TRX) is a multi-functional redox protein. Genome-wide survey and expression profiles of different stresses were observed. Conserved amino acid residues and phylogeny construction using the OsTRX conserved domain sequence suggest that the TRX gene family can be classified broadly into six subfamilies in rice. We compared potential gene birth-and-death events in the OsTRX genes. The Ka/Ks ratio is a measure to explore the mechanism and 3 evolutionary stages of the OsTRX genes divergence after duplication. We used 270 TRX genes from monocots and eudicots for synteny analysis. Furthermore, we investigated expression profiles of this gene family under 5 biotic and 3 abiotic stresses. Several genes were differentially expressed with high levels of expression and exhibited subfunctionalization and neofunctionalization after the duplication event response to different stresses, which provides novel reference for the cloning of the most promising candidate genes from OsTRX gene family for further functional analysis. 相似文献
25.
Shabanpoor F Bathgate RA Belgi A Chan LJ Nair VB Wade JD Hossain MA 《Biochemical and biophysical research communications》2012,420(2):253-256
Diethylenetriamine pentaacetic acid (DTPA) is a popular chelator agent for enabling the labeling of peptides for their use in structure-activity relationship study and biodistribution analysis. Solid phase peptide synthesis was employed to couple this commercially available chelator at the N-terminus of either the A-chain or B-chain of H2 relaxin. The coupling of the DTPA chelator at the N-terminus of the B-chain and subsequent loading of a lanthanide (europium) ion into the chelator led to a labeled peptide (Eu-DTPA-(B)-H2) in low yield and having very poor water solubility. On the other hand, coupling of the DTPA and loading of Eu at the N-terminus of the A-chain led to a water-soluble peptide (Eu-DTPA-(A)-H2) with a significantly improved final yield. The conjugation of the DTPA chelator at the N-terminus of the A-chain did not have any impact on the secondary structure of the peptide determined by circular dichroism spectroscopy (CD). On the other hand, it was not possible to determine the secondary structure of Eu-DTPA-(B)-H2 because of its insolubility in phosphate buffer. The B-chain labeled peptide Eu-DTPA-(B)-H2 required solubilization in DMSO prior to carrying out binding assays, and showed lower affinity for binding to H2 relaxin receptor, RXFP1, compared to the water-soluble A-chain labeled peptide Eu-DTPA-(A)-H2. The mono-Eu-DTPA labeled A-chain peptide, Eu-DTPA-(A)-H2, thus can be used as a valuable probe to study ligand-receptor interactions of therapeutically important H2 relaxin analogs. Our results show that it is critical to choose an approriate site for incorporating chelators such as DTPA. Otherwise, the bulky size of the chelator, depending on the site of incorporation, can affect yield, solubility, structure and pharmacological profile of the peptide. 相似文献
26.
Gavrilin MA Abdelaziz DH Mostafa M Abdulrahman BA Grandhi J Akhter A Abu Khweek A Aubert DF Valvano MA Wewers MD Amer AO 《Journal of immunology (Baltimore, Md. : 1950)》2012,188(7):3469-3477
Burkholderia cenocepacia is an opportunistic pathogen that causes chronic infection and induces progressive respiratory inflammation in cystic fibrosis patients. Recognition of bacteria by mononuclear cells generally results in the activation of caspase-1 and processing of IL-1β, a major proinflammatory cytokine. In this study, we report that human pyrin is required to detect intracellular B. cenocepacia leading to IL-1β processing and release. This inflammatory response involves the host adapter molecule ASC and the bacterial type VI secretion system (T6SS). Human monocytes and THP-1 cells stably expressing either small interfering RNA against pyrin or YFP-pyrin and ASC (YFP-ASC) were infected with B. cenocepacia and analyzed for inflammasome activation. B. cenocepacia efficiently activates the inflammasome and IL-1β release in monocytes and THP-1. Suppression of pyrin levels in monocytes and THP-1 cells reduced caspase-1 activation and IL-1β release in response to B. cenocepacia challenge. In contrast, overexpression of pyrin or ASC induced a robust IL-1β response to B. cenocepacia, which correlated with enhanced host cell death. Inflammasome activation was significantly reduced in cells infected with T6SS-defective mutants of B. cenocepacia, suggesting that the inflammatory reaction is likely induced by an as yet uncharacterized effector(s) of the T6SS. Together, we show for the first time, to our knowledge, that in human mononuclear cells infected with B. cenocepacia, pyrin associates with caspase-1 and ASC forming an inflammasome that upregulates mononuclear cell IL-1β processing and release. 相似文献
27.
One of the most recognised and studied family of peptide hormones is the insulin superfamily. Within this family is the relaxin subfamily which comprises seven members: relaxin-1, -2 and -3 and insulin-like peptides 3, 4, 5 and 6. Besides exhibiting sequence similarities, each member exists as an active A-B heterodimer linked by three disulfide bonds. This mini-review is divided into three broad themes: an overview of all insulin superfamily members (including structural similarities); roles of each superfamily member and finally, a focus on the pleiotropic peptide hormone, human relaxin-2. In addition to promoting vasodilatory effects leading to evaluation in Phase III clinical trials for the treatment of acute heart failure, relaxin has recently been shown to be highly expressed by cancer cells, aiding in their proliferation, invasiveness and metastasis. These contrary effects of relaxin are discussed together with current efforts in the development of relaxin antagonists that may possess future therapeutic potential for the treatment of certain cancers. 相似文献
28.
A new species of cicada, Cicadatra ziaraticasp. n., is described from Pakistan. Male genitalia, timbal and opercula are described and illustrated as important diagnostic characters. Biological notes are also provided. A key to the known Cicadatra of Pakistan is provided. 相似文献
29.