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排序方式: 共有222条查询结果,搜索用时 15 毫秒
111.
Lova P Paganini S Sinigaglia F Balduini C Torti M 《The Journal of biological chemistry》2002,277(14):12009-12015
Stimulation of human platelets by cross-linking of the low affinity receptor for immunoglobulin, FcgammaRIIA, caused the rapid activation of the small GTPase Rap1B, as monitored by accumulation of the GTP-bound form of the protein. This process was totally dependent on the action of secreted ADP since it was completely prevented in the presence of either apyrase or creatine phosphate and creatine phosphokinase. Dose-dependent experiments revealed that the inhibitory effect of ADP scavengers was not related to the reduced increase of cytosolic Ca(2+) concentration in stimulated platelets. Activation of Rap1B induced by clustering of FcgammaRIIA was totally suppressed by AR-C69931MX, a specific antagonist of the G(i)-coupled ADP receptor P2Y12, but was not affected by blockade of the G(q)-coupled receptor, P2Y1. Similarly, direct stimulation of platelets with ADP induced the rapid activation of Rap1B. Pharmacological blockade of the P2Y1 receptor totally prevented ADP-induced Ca(2+) mobilization but did not affect activation of Rap1B. By contrast, prevention of ADP binding to the P2Y12 receptor totally suppressed activation of Rap1B without affecting Ca(2+) signaling. In platelets stimulated by cross-linking of FcgammaRIIA, inhibition of Rap1B activation by ADP scavengers could be overcome by the simultaneous recruitment of the G(i)-coupled alpha(2A)-adrenergic receptor by epinephrine. By contrast, serotonin, which binds to a G(q)-coupled receptor, could not restore activation of Rap1B. When tested alone, epinephrine was found to be able to induce GTP binding to Rap1B, whereas serotonin produced only a slight effect. Finally, activation of Rap1B induced by stimulation of the G(q)-coupled thromboxane A(2) receptor by was completely inhibited by ADP scavengers under conditions in which intracellular Ca(2+) mobilization was unaffected. Inhibition of -induced Rap1B activation was also observed upon blockade of the P2Y12 but not of the P2Y1 receptor for ADP. These results demonstrate that stimulation of a G(i)-dependent signaling pathway by either ADP of epinephrine is necessary and sufficient to activate the small GTPase Rap1B. 相似文献
112.
McNally JJ Youngman MA Lovenberg TW Nepomuceno D Wilson S Dax SL 《Bioorganic & medicinal chemistry letters》2000,10(15):1641-1643
Alpha-(3-Pyridylmethyl)-beta-aminotetralins were acylated with amino-piperidinyl and-pyrrolidinyl acetic acids, and with (aminomethyl)cyclohexanecarboxylic acid. Reaction with acyl chlorides, chloroformates, and isocyanates gave amides 8e, carbamates 9, and ureas 10, which bound to the Y5 receptor with nanomolar affinity. Congeners 11a and 11d containing a terminal benzimidazolone group were shown to be functional Y5 antagonists. 相似文献
113.
Randrianarison Rose Marie Lutz Meredith Torti Valeria Tan Chia Bonadonna Giovanna Randrianambinina Blanchard Rasoloharijaona Solofonirina Rabarison Harison Miaretsoa Longondraza Rarojoson Nianja Jemisa De Gregorio Chiara Valente Daria Gamba Marco Ratsimbazafy Jonah Giacoma Cristina 《International journal of primatology》2022,43(5):987-987
International Journal of Primatology - 相似文献
114.
Miaretsoa Longondraza Cascella Andrea Vadàla Luigi Valente Daria De Gregorio Chiara Torti Valeria Norscia Ivan Ratsimbazafy Jonah Friard Olivier Giacoma Cristina Gamba Marco 《International journal of primatology》2022,43(4):611-635
International Journal of Primatology - In mammals, olfactory communication plays an essential role in territorial and mating dynamics. Scent depositions in various species, including lemurs, can be... 相似文献
115.
Giuseppe Lapadula Liliane Chatenoud Andrea Gori Francesco Castelli Simona Di Giambenedetto Massimiliano Fabbiani Franco Maggiolo Emanuele Focà Nicoletta Ladisa Laura Sighinolfi Massimo Di Pietro Angelo Pan Carlo Torti Italian MASTER Cohort 《PloS one》2015,10(5)
BackgroundImmunological non-response (INR) despite virological suppression is associated with AIDS-defining events/death (ADE). Little is known about its association with serious non-AIDS-defining events (nADE).MethodsPatients highly-active antiretroviral therapy (HAART) with <200 CD4+/μl and achieving HIV-RNA <50 copies/ml within 12 (±3) months were categorized as INR if CD4+ T-cell count at year 1 was <200/μl. Predictors of nADE (malignancies, severe infections, renal failure—ie, estimated glomerular filtration rate <30 ml/min, cardiovascular events and liver decompensation) were assessed using multivariable Cox models. Follow-up was right-censored in case of HAART discontinuation or confirmed HIV-RNA>50.Results1221 patients were observed for a median of 3 (IQR: 1.3-6.1) years. Pre-HAART CD4+ were 77/μl (IQR: 28-142) and 56% of patients had experienced an ADE. After 1 year, CD4+ increased to 286 (IQR: 197-387), but 26.1% of patients were INR. Thereafter, 86 nADE (30.2% malignancies, 27.9% infectious, 17.4% renal, 17.4% cardiovascular, 7% hepatic) were observed, accounting for an incidence of 1.83 events (95%CI: 1.73-2.61) per 100 PYFU. After adjusting for measurable confounders, INR had a significantly greater risk of nADE (HR 1.65; 95%CI: 1.06-2.56). Older age (per year, HR 1.03; 95%CI: 1.01-1.05), hepatitis C co-infection (HR 2.09; 95%CI: 1.19-3.7), a history of previous nADE (HR 2.16; 95%CI: 1.06-4.4) and the occurrence of ADE during the follow-up (HR 2.2; 95%CI: 1.15-4.21) were other independent predictors of newly diagnosed nADE.ConclusionsPatients failing to restore CD4+ to >200 cells/μl run a greater risk of serious nADE, which is intertwined or predicted by AIDS progression. Improved management of this fragile population and innovative therapy able to induce immune-reconstitution are urgently needed. Also, our results strengthen the importance of earlier diagnosis and HAART introduction. 相似文献
116.
Torti SV Byrne F Whelan O Levi N Ucer B Schmid M Torti FM Akman S Liu J Ajayan PM Nalamasu O Carroll DL 《International journal of nanomedicine》2007,2(4):707-714
We demonstrate that nitrogen doped, multi-walled carbon nanotubes (CN(x)-MWNT) result in photo-ablative destruction of kidney cancer cells when excited by near infrared (NIR) irradiation. Further, we show that effective heat transduction and cellular cytotoxicity depends on nanotube length: effective NIR coupling occurs at nanotube lengths that exceed half the wavelength of the stimulating radiation, as predicted in classical antenna theory. We also demonstrate that this radiation heats the nanotubes through induction processes, resulting in significant heat transfer to surrounding media and cell killing at extraordinarily small radiation doses. This cell death was attributed directly to photothermal effect generated within the culture, since neither the infrared irradiation itself nor the CN(x)-MWNT were toxic to the cells. 相似文献
117.
Chiara De Gregorio Filippo Carugati Vittoria Estienne Daria Valente Teresa Raimondi Valeria Torti Longondraza Miaretsoa Jonah Ratsimbazafy Marco Gamba Cristina Giacoma 《动物学报(英文版)》2021,67(6):597
In animal vocal communication, the development of adult-like vocalization is fundamental to interact appropriately with conspecifics. However, the factors that guide ontogenetic changes in the acoustic features remain poorly understood. In contrast with a historical view of nonhuman primate vocal production as substantially innate, recent research suggests that inheritance and physiological modification can only explain some of the developmental changes in call structure during growth. A particular case of acoustic communication is the indris’ singing behavior, a peculiar case among Strepsirrhine primates. Thanks to a decade of intense data collection, this work provides the first long-term quantitative analysis on song development in a singing primate. To understand the ontogeny of such a complex vocal output, we investigated juvenile and sub-adult indris’ vocal behavior, and we found that young individuals started participating in the chorus years earlier than previously reported. Our results indicated that spectro-temporal song parameters underwent essential changes during growth. In particular, the age and sex of the emitter influenced the indris’ vocal activity. We found that frequency parameters showed consistent changes across the sexes, but the temporal features showed different developmental trajectories for males and females. Given the low level of morphological sexual dimorphism and the marked differences in vocal behavior, we hypothesize that factors like social influences and auditory feedback may affect songs’ features, resulting in high vocal flexibility in juvenile indris. This trait may be pivotal in a species that engages in choruses with rapid vocal turn-taking. 相似文献
118.
Doxorubicin Overproduction in Streptomyces peucetius: Cloning and Characterization of the dnrU Ketoreductase and dnrV Genes and the doxA Cytochrome P-450 Hydroxylase Gene 总被引:7,自引:0,他引:7
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Natalie Lomovskaya Sharee L. Otten Yukiko Doi-Katayama Leonid Fonstein Xiao-Chun Liu Toshio Takatsu Augusto Inventi-Solari Silvia Filippini Francesca Torti Anna Luisa Colombo C. Richard Hutchinson 《Journal of bacteriology》1999,181(1):305-318
Doxorubicin-overproducing strains of Streptomyces peucetius ATCC 29050 can be obtained through manipulation of the genes in the region of the doxorubicin (DXR) gene cluster that contains dpsH, the dpsG polyketide synthase gene, the putative dnrU ketoreductase gene, dnrV, and the doxA cytochrome P-450 gene. These five genes were characterized by sequence analysis, and the effects of replacing dnrU, dnrV, doxA, or dpsH with mutant alleles and of doxA overexpression on the production of the principal anthracycline metabolites of S. peucetius were studied. The exact roles of dpsH and dnrV could not be established, although dnrV is implicated in the enzymatic reactions catalyzed by DoxA, but dnrU appears to encode a ketoreductase specific for the C-13 carbonyl of daunorubicin (DNR) and DXR or their biosynthetic precursors. The highest DXR titers were obtained in a dnrX dnrU (N. Lomovskaya, Y. Doi-Katayama, S. Filippini, C. Nastro, L. Fonstein, M. Gallo, A. L. Colombo, and C. R. Hutchinson, J. Bacteriol. 180:2379–2386, 1998) double mutant and a dnrX dnrU dnrH (C. Scotti and C. R. Hutchinson, J. Bacteriol. 178:7316–7321, 1996) triple mutant. Overexpression of doxA in a doxA::aphII mutant resulted in the accumulation of DXR precursors instead of in a notable increase in DXR production. In contrast, overexpression of dnrV and doxA jointly in the dnrX dnrU double mutant or the dnrX dnrU dnrH triple mutant increased the DXR titer 36 to 86%. 相似文献
119.
TA1 cells, like 3T3-L1 cells, undergo a differentiation process in vitro from a fibroblast to an adipocyte phenotype. The TA1 pre-adipocytes were found to have low numbers of insulin receptors but high numbers of receptors for insulin-like growth factors (IGF) I and II. Also, the pre-adipocytes were more responsive to IGF than insulin as measured by either stimulation of glucose or amino acid uptake. After differentiation, the adipocytes had higher numbers of insulin receptors and a better responsitivity to insulin than to IGF-I. These results indicate that insulin-like growth factors are the primary regulators of the pre-adipocytes whereas insulin regulates the adipocytes. 相似文献
120.
Modulation of adipocyte differentiation by tumor necrosis factor and transforming growth factor beta 总被引:4,自引:0,他引:4
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![点击此处可从《The Journal of cell biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Cultured TA1 adipocytes treated with tumor necrosis factor alpha (TNF) lose intracytoplasmic lipid and, over a period of days, come to resemble their predifferentiated progenitors (preadipocytes). To examine the extent to which this phenotypic reversion represents a return to a less differentiated cell, we examined three major characteristics that distinguish preadipocytes from adipocytes: (a) pattern of gene expression; (b) hormonal requirement for accelerated adipogenesis; and (c) pattern of protein synthesis. We found that within hours of TNF addition to adipocytes, mRNAs for genes whose expression is augmented during adipogenesis decreased to predifferentiated levels; in addition, like preadipocytes, TNF-treated adipocytes required exposure to hormones to accelerate adipogenesis. Further, the pattern of protein synthesis seen on polyacrylamide gels reverted to that seen before differentiation. Transforming growth factor-beta (TGF-beta) also caused a rapid decrease in expression of adipose genes when added to fully differentiated cells, an effect that was achieved by treatment with either TGF-beta 1 or TGF-beta 2. These effects were seen in the absence of a demonstrable proliferative response to either TNF or TGF-beta. Thus characteristics that define the "terminally" differentiated state in adipocytes are subject to modulation by environmental influences. 相似文献