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排序方式: 共有270条查询结果,搜索用时 546 毫秒
261.
Mathieu C Morissette Brian N Jobse Danya Thayaparan Jake K Nikota Pamela Shen Nancy Renée Labiris Roland Kolbeck Parameswaran Nair Alison A Humbles Martin R St?mpfli 《Respiratory research》2014,15(1):49
Formation of pulmonary tertiary immune structures is a characteristic feature of advanced COPD. In the current study, we investigated the mechanisms of tertiary lymphoid tissue (TLT) formation in the lungs of cigarette smoke-exposed mice. We found that cigarette smoke exposure led to TLT formation that persisted following smoking cessation. TLTs consisted predominantly of IgM positive B cells, while plasma cells in close proximity to TLTs expressed IgM, IgG, and IgA. The presence of TLT formation was associated with anti-nuclear autoantibody (ANA) production that also persisted following smoking cessation. ANAs were observed in the lungs, but not the circulation of cigarette smoke-exposed mice. Similarly, we observed ANA in the sputum of COPD patients where levels correlated with disease severity and were refractory to steroid treatment. Both ANA production and TLT formation were dependent on interleukin-1 receptor 1 (IL-1R1) expression. Contrary to TLT and ANA, lung neutrophilia resolved following smoking cessation. These data suggest a differential regulation of innate and B cell-related immune inflammatory processes associated with cigarette smoke exposure. Moreover, our study further emphasizes the importance of interleukin-1 (IL-1) signaling pathways in cigarette smoke-related pulmonary pathogenesis. 相似文献
262.
263.
Sai Cayalvizhi B. Chidambaranathan Parameswaran Samantaray Sangamitra 《Molecular biology reports》2022,49(3):2169-2183
Molecular Biology Reports - The potential of paddy breeding has reached its pinnacle, and hybrids have been the principal research outcome. Hence, our hypothesis was based on improvising the callus... 相似文献
264.
N. Parameswaran 《Plant biology (Stuttgart, Germany)》1968,81(6):199-202
In den aus parenchymatischen Zellen hervorgehenden Skiereiden des sekundären Phloems wurden einige besondere Strukturen beobachtet. Bei Dialyanthera otoba und Myristica fragrans kommen in diesen Zellen zungenförmige Einstülpungen der Zellwand vor, die in das Lumen hineinreichen. In den Skiereiden des Phelloderms bei Salmalia malabarica sind Trabekelnähnliche intrazelluläre Stabbildungen vorhanden. Die tangential gestreckten und skierotisierten Zellen des Dilatationsgewebes bei Balanocarpus brevipetiolaris, Hopea pierrei, Shorea multiflora, Vatica papuana, V. wallichii u. a. besitzen ein radial verlaufendes membranartiges Septum, das im Gegensatz zur Zellwand cellulosehaltig ist. 相似文献
265.
L Lorand K N Parameswaran P Stenberg Y S Tong P T Velasco N A J?nsson L Mikiver P Moses 《Biochemistry》1979,18(9):1756-1765
The amine specificity of guinea pig liver transglutaminase, a model enzyme for endo-gamma-glutamine:epsilon-lysin transferases, was explored with the aid of synthetic substrates of high apparent affinities. As exemplified by dansyl- (5-dimethylamino-1-naphthalenesulfonyl), (2,4-dinitrobenzenesulfonyl)-, and (2,4,6-triisopropylbenzenesulfonyl)-cadaverines--each of which showed affinities of approximately 4 x 10(7) M-1--the best amine substrates carried a large hydrophobic substituent attached to an alkylamine side chain of about 7.2 A in length. Altogether, our results point to the importance of a hydrophobic binding region in the enzyme from where the alkyl side chain reaches into a narrow crevice toward the active center and positions the primary amine of the substrate for attacking the carbonyl group of the acyl enzyme intermediate. 相似文献
266.
Journal of Plant Research - Yellow mosaic disease (YMD) of pulses caused by mungbean yellow mosaic virus is a major threat to crop production. An infection that is compatible with regulating and... 相似文献
267.
Narayan Parameswaran 《Protoplasma》1976,87(4):447-451
Summary The presence and structure of intercellular strands between sclerotic phelloids in the lenticel tissue of spruce bark have been described and their probable origin discussed. 相似文献
268.
Yingying Hu Liang Shi Dongxing Du Siva Parameswaran 《Computer methods in biomechanics and biomedical engineering》2013,16(1):66-72
A numerical method of the left ventricle (LV) deformation, an elongation model, was put forth for the study of LV fluid mechanics in diastole. The LV elongated only along the apical axis, and the motion was controlled by the intraventricular flow rate. Two other LV models, a fixed control volume model and a dilation model, were also used for model comparison and the study of LV fluid mechanics. For clinical sphere indices (SIs, between 1.0 and 2.0), the three models showed little difference in pressure and velocity distributions along the apical axis at E-peak. The energy dissipation was lower at a larger SI in that the jet and vortex development was less limited by the LV cavity in the apical direction. LV deformation of apical elongation may represent the primary feature of LV deformation in comparison with the secondary radial expansion. The elongation model of the LV deformation with an appropriate SI is a reasonable, simple method to study LV fluid mechanics in diastole. 相似文献
269.
270.
AG Delgado P Parameswaran D Fajardo-Williams RU Halden R Krajmalnik-Brown 《Microbial cell factories》2012,11(1):128
ABSTRACT: BACKGROUND: Buffering to achieve pH control is crucial for successful trichloroethene (TCE) anaerobic bioremediation. Bicarbonate (HCO3-) is the natural buffer in groundwater and the buffer of choice in the laboratory and at contaminated sites undergoing biological treatment with organohalide respiring microorganisms. However, HCO3- also serves as the electron acceptor for hydrogenotrophic methanogens and hydrogenotrophic homoacetogens, two microbial groups competing with organohalide respirers for hydrogen (H2). We studied the effect of HCO3- as a buffering agent and the effect of HCO3--consuming reactions in a range of concentrations (2.5-30 mM) with an initial pH of 7.5 in H2-fed TCE reductively dechlorinating communities containing Dehalococcoides, hydrogenotrophic methanogens, and hydrogenotrophic homoacetogens. RESULTS: Rate differences in TCE dechlorination were observed as a result of added varying HCO3- concentrations due to H2-fed electrons channeled towards methanogenesis and homoacetogenesis and pH increases (up to 8.7) from biological HCO3- consumption. Significantly faster dechlorination rates were noted at all HCO3- concentrations tested when the pH buffering was improved by providing 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) as an additional buffer. Electron balances and quantitative PCR revealed that methanogenesis was the main electron sink when the initial HCO3- concentrations were 2.5 and 5 mM, while homoacetogenesis was the dominant process and sink when 10 and 30 mM HCO3- were provided initially. CONCLUSIONS: Our study reveals that HCO3- is an important variable for bioremediation of chloroethenes as it has a prominent role as an electron acceptor for methanogenesis and homoacetogenesis. It also illustrates the changes in rates and extent of reductive dechlorination resulting from the combined effect of electron donor competition stimulated by HCO3- and the changes in pH exerted by methanogens and homoacetogens. 相似文献