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771.
Binh-An Truong Quang Madhav Mani Olga Markova Thomas Lecuit Pierre-François Lenne 《Current biology : CB》2013,23(22):2197-2207
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772.
Andrew N. Luu Lorenzo Anez-Bustillos Shima Aran Francisco J. Araiza Arroyo Vahid Entezari Claudio Rosso Brian D. Snyder Ara Nazarian 《PloS one》2013,8(12)
Background
High resolution μCT, and combined μPET/CT have emerged as non-invasive techniques to enhance or even replace dual energy X-ray absorptiometry (DXA) as the current preferred approach for fragility fracture risk assessment. The aim of this study was to assess the ability of µPET/CT imaging to differentiate changes in rat bone tissue density and microstructure induced by metabolic bone diseases more accurately than current available methods.Methods
Thirty three rats were divided into three groups of control, ovariectomy and vitamin-D deficiency. At the conclusion of the study, animals were subjected to glucose (18FDG) and sodium fluoride (Na18F) PET/CT scanning. Then, specimens were subjected to µCT imaging and tensile mechanical testing.Results
Compared to control, those allocated to ovariectomy and vitamin D deficiency groups showed 4% and 22% (significant) increase in 18FDG uptake values, respectively. DXA-based bone mineral density was higher in the vitamin D deficiency group when compared to the other groups (cortical bone), yet μCT-based apparent and mineral density results were not different between groups. DXA-based bone mineral density was lower in the ovariectomy group when compared to the other groups (cancellous bone); yet μCT-based mineral density results were not different between groups, and the μCT-based apparent density results were lower in the ovariectomy group compared to the other groups.Conclusion
PET and micro-CT provide an accurate three-dimensional measurement of the changes in bone tissue mineral density, as well as microstructure for cortical and cancellous bone and metabolic activity. As osteomalacia is characterized by impaired bone mineralization, the use of densitometric analyses may lead to misinterpretation of the condition as osteoporosis. In contrast, µCT alone and in combination with the PET component certainly provides an accurate three-dimensional measurement of the changes in both bone tissue mineral density, as well as microstructure for cortical and cancellous bone and metabolic activity. 相似文献773.
Nga?Luu Luan?Wen Liezhen?Fu Kenta?Fujimoto Yun-Bo?ShiEmail author Guihong?SunEmail author 《Cell & Bioscience》2013,3(1):43
Background
Organ-specific, adult stem cells are essential for organ-homeostasis and tissue repair and regeneration. The formation of such stem cells during vertebrate development remains to be investigated. Frog metamorphosis offers an excellent opportunity to study the formation of adult stem cells as this process involves essentially the transformations of all larval tissues/organs into the adult form. Of particular interest is the remodeling of the intestine. Early studies in Xenopus laevis have shown that this process involves complete degeneration of the larval epithelium and de novo formation of adult stem cells through dedifferentiation of some larval epithelial cells. A major advantage of this metamorphosis model is its total dependence on thyroid hormone (T3). In an effort to identify genes that are important for stem cell development, we have previously carried out tissue-specific microarray analysis of intestinal gene expression during Xenopus laevis metamorphosis.Results
We report the detailed characterization of one of the genes thus identified, the histidine ammonia-lyase (HAL) gene, which encodes an enzyme known as histidase or histidinase. We show that there are two duplicated HAL genes, HAL1 and HAL2, in both Xenopus laevis and Xenopus tropicalis, a highly related but diploid species. Interestingly, only HAL2 is highly upregulated by T3 and appears to be specifically expressed in the adult intestinal progenitor/stem cells while HAL1 is not expressed in the intestine during metamorphosis. Furthermore, when analyzed in whole animals, HAL1 appears to be expressed only during embryogenesis but not metamorphosis while the opposite appears to be true for HAL2.Conclusions
Our results suggest that the duplicated HAL genes have distinct functions with HAL2 likely involved in the formation and/or proliferation of the adult stem cells during metamorphosis.774.
Dang Thach Tran Huong Doan Thi Mai Van Cuong Pham Van Hung Nguyen Marc Litaudon Françoise Guéritte Quoc Vuong Nguyen Tuan Anh Tran Van Minh Chau 《Phytochemistry letters》2013,6(1):79-83
Three new compounds, goniotamirine (1), goniotamiric acid (2), and 3,5-demethoxypiperolide (3) were isolated from the leaves of Goniothalamus tamirensis (Annonaceae), together with sixteen known compounds, (?)-N-nornuciferine (4), (?)-norisocorydine (5), (?)-isocorydine (6), (?)-3-hydroxynornuceferine (7), (?)-O-methylisopiline (8), (?)-anonaine (9), (?)-roemerine (10), (?)-roemeroline (11), (?)-boldine (12), glaunine (13), liriodenine (14), 9-deoxygoniopypyrone (15), 8-epi-9-deoxygoniopypyrone (16), 8-epi-9-deoxygoniopypyrone acetate (17), goniodiol (18) and goniothalamin (19). The structures were established from spectral analysis, including mass spectrometry and 2D-NMR. The absolute configuration of 1 was determined from analysis of its MTPA amide derivatives. The cytotoxicity of all isolates was evaluated against KB cells. Only compound 4 (N-nornuciferine) showed a moderate activity with an IC50 value of 12 μg/mL. 相似文献
775.
Nguyen Thi Le Hang Shinji Maeda Luu Thi Lien Pham Huu Thuong Nguyen Van Hung Tran Bich Thuy Akiko Nanri Tetsuya Mizoue Nguyen Phuong Hoang Vu Cao Cuong Khieu Thi Thuy Ngoc Shinsaku Sakurada Hiroyoshi Endo Naoto Keicho 《PloS one》2013,8(8)
Introduction
Resistance of Mycobacterium tuberculosis (MTB) to anti-tuberculosis (TB) drugs presents a serious challenge to TB control worldwide. We investigated the status of drug resistance, including multidrug-resistant (MDR) TB, and possible risk factors among newly diagnosed TB patients in Hanoi, the capital of Viet Nam.Methods
Clinical and epidemiological information was collected from 506 newly diagnosed patients with sputum smear- and culture-positive TB, and 489 (96.6%) MTB isolates were subjected to conventional drug susceptibility testing, spoligotyping, and 15-locus variable numbers of tandem repeats typing. Adjusted odds ratios (aORs) were calculated to analyze the risk factors for primary drug resistance.Results
Of 489 isolates, 298 (60.9%) were sensitive to all drugs tested. Resistance to isoniazid, rifampicin, streptomycin, ethambutol, and MDR accounted for 28.2%, 4.9%, 28.2%, 2.9%, and 4.5%, respectively. Of 24 isolates with rifampicin resistance, 22 (91.7%) were MDR and also resistant to streptomycin, except one case. Factors associated with isoniazid resistance included living in old urban areas, presence of the Beijing genotype, and clustered strains [aOR = 2.23, 95% confidence interval (CI) 1.15–4.35; 1.91, 1.18–3.10; and 1.69, 1.06–2.69, respectively). The Beijing genotype was also associated with streptomycin resistance (aOR = 2.10, 95% CI 1.29–3.40). Human immunodeficiency virus (HIV) coinfection was associated with rifampicin resistance and MDR (aOR = 5.42, 95% CI 2.07–14.14; 6.23, 2.34–16.58, respectively).Conclusion
Isoniazid and streptomycin resistance was observed in more than a quarter of TB patients without treatment history in Hanoi. Transmission of isoniazid-resistant TB among younger people should be carefully monitored in urban areas, where Beijing strains and HIV coinfection are prevalent. Choosing an optimal treatment regimen on the basis of the results of drug susceptibility tests and monitoring of treatment adherence would minimize further development of drug resistance strains. 相似文献776.
777.
778.
779.
Landgraf P Rusu M Sheridan R Sewer A Iovino N Aravin A Pfeffer S Rice A Kamphorst AO Landthaler M Lin C Socci ND Hermida L Fulci V Chiaretti S Foà R Schliwka J Fuchs U Novosel A Müller RU Schermer B Bissels U Inman J Phan Q Chien M Weir DB Choksi R De Vita G Frezzetti D Trompeter HI Hornung V Teng G Hartmann G Palkovits M Di Lauro R Wernet P Macino G Rogler CE Nagle JW Ju J Papavasiliou FN Benzing T Lichter P Tam W Brownstein MJ Bosio A Borkhardt A Russo JJ Sander C Zavolan M Tuschl T 《Cell》2007,129(7):1401-1414
780.
Tran Thanh Thu Eric Dewaele Le Quang Trung Martine Claeys Michel Jacobs Geert Angenon 《Plant Cell, Tissue and Organ Culture》2007,91(2):135-143
In higher plants the essential amino acids lysine, threonine, methionine and isoleucine are synthesised through a branched
pathway starting from aspartate. The key enzyme of lysine biosynthesis in this pathway—dihydrodipicolinate synthase (DHDPS)—is
feedback-inhibited by lysine. The dhdps-r1 gene from a mutant Nicotiana sylvestris, which encodes a DHDPS enzyme insensitive to feedback inhibition, was used to improve the lysine content in pigeonpea seeds.
The dhdps-r1 coding region driven by a phaseolin or an Arabidopsis 2S2 promoter was successfully overexpressed in the seeds of pigeonpea
by using Agrobacterium transformation and particle bombardment. In 11 lines analysed, a 2- to 6-fold enhanced DHDPS activity in immature seeds at
a late stage of maturation was found in comparison to wild type. The overexpression of dhdps-r1 led to an enhanced content of free lysine in the seeds of pigeonpea from 1.6 to 8.5 times compared with wild type. However,
this was not reflected in an increase in total seed lysine content. This might be explained by a temporal discrepancy between
maximal expression of dhdps-r1 and the rate of amino acid incorporation into storage proteins. Assays of the lysine degradative enzyme lysine-ketoglutarate
reductase in these seeds showed no co-ordinated regulation of lysine biosynthesis and catabolism during seed maturation. All
transgenic plants were fertile and produced morphologically normal seeds. 相似文献