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Prolonged Phase (prolonged + phase)
Selected AbstractsIn vivo observation of the locomotion of microglial cells in the retinaGLIA, Issue 14 2010Michel Paques Abstract Microglial cells (MCs) are active sensors and reactive phagocytes of neural tissues. They are known to migrate and accumulate in areas of neuronal damage. Thus, microglial locomotion is an essential feature of the inflammatory reaction in neural tissue. Yet, to our knowledge there has been no report of direct in vivo observation of the migration of MCs. Here, we show that intravitreally injected cyanine dyes (DiO, DiI, and indocyanine green) are sequestrated in MCs during several months, and subsequently in vivo images of these fluorescent MCs can be obtained by confocal scanning laser ophthalmoscopy. This enabled noninvasive, time-lapse observation of the migrating behavior of MCs, both in the basal state and following laser damage. In the basal state, a slow, intermittent, random-like locomotion was observed. Following focal laser damage, MCs promptly (i.e., within 1 h) initiated centripetal, convergent migration. MCs up to 400 ,m away migrated into the scar at velocities up to 7 ,m/min. This early phase of centripetal migration was followed by a more prolonged phase of nontargeted locomotion around and within injured sites during at least 24 h. Cyanine-positive cells persisted within the scar during several weeks. To our knowledge, this is the first in vivo observation of the locomotion of individual MCs. Our results show that the locomotion of MCs is not limited to translocation to acutely damaged area, but may also be observed in the basal state and after completion of the recruitment of MCs into scars. © 2010 Wiley-Liss, Inc. [source] The effect of elevated CO2 on diel leaf growth cycle, leaf carbohydrate content and canopy growth performance of Populus deltoidesGLOBAL CHANGE BIOLOGY, Issue 8 2005Achim Walter Abstract Image sequence processing methods were applied to study the effect of elevated CO2 on the diel leaf growth cycle for the first time in a dicot plant. Growing leaves of Populus deltoides, in stands maintained under ambient and elevated CO2 for up to 4 years, showed a high degree of heterogeneity and pronounced diel variations of their relative growth rate (RGR) with maxima at dusk. At the beginning of the season, leaf growth did not differ between treatments. At the end of the season, final individual leaf area and total leaf biomass of the canopy was increased in elevated CO2. Increased final leaf area at elevated CO2 was achieved via a prolonged phase of leaf expansion activity and not via larger leaf size upon emergence. The fraction of leaves growing at 30,40% day,1 was increased by a factor of two in the elevated CO2 treatment. A transient minimum of leaf expansion developed during the late afternoon in leaves grown under elevated CO2 as the growing season progressed. During this minimum, leaves grown under elevated CO2 decreased their RGR to 50% of the ambient value. The transient growth minimum in the afternoon was correlated with a transient depletion of glucose (less than 50%) in the growing leaf in elevated CO2, suggesting diversion of glucose to starch or other carbohydrates, making this substrate temporarily unavailable for growth. Increased leaf growth was observed at the end of the night in elevated CO2. Net CO2 exchange and starch concentration of growing leaves was higher in elevated CO2. The extent to which the transient reduction in diel leaf growth might dampen the overall growth response of these trees to elevated CO2 is discussed. [source] Management of lentigo maligna and lentigo maligna melanoma: Seminars in surgical oncology,JOURNAL OF SURGICAL ONCOLOGY, Issue 4 2004FRCPC, John P. Arlette MD Abstract Lentigo maligna (LM) and lentigo maligna melanoma (LMM) represent a character, histogenetic subclass of melanocytic malignancies. They often present with a prolonged phase of slow growth but once invasion has occurred, the prognostic features are identical to all other melanomas. These lesions occur primarily on the head and neck where they evolve from areas of pigmented staining to the more typical features identifiable with malignant melanomas on other skin surfaces. The treatment options and recent advances in management are reviewed. J. Surg. Oncol. 2004;86:179,186. © 2004 Wiley-Liss, Inc. [source] Trilostane treatment in dogs with pituitary-dependent hyperadreno-corticismAUSTRALIAN VETERINARY JOURNAL, Issue 10 2003JA BRADDOCK Objective To evaluate the efficacy of trilostane in treating dogs with pituitary-dependent hyperadrenocorticism. Design Prospective clinical trial using client-owned dogs with pituitary-dependent hyperadrenocorticism treated at University Veterinary Centre, Sydney from September 1999 to July 2001. Procedure Thirty dogs with pituitary-dependent hyperadrenocorticism treated with trilostane, a competitive inhibitor ,-HSD, were monitored at days 10, 30 and 90 then 3-monthly by clinical examination, tetracosactrin stimulation testing, urinary corticoid:creatinine ratio measurement and by client questionnaire. Results Twenty-nine of 30 dogs were successfully treated with trilostane (median dose 16.7 mg/kg; range 5.3 to 50 mg/kg, administered once daily); one responded favourably but died of unrelated disease before full control was achieved. Conclusion Trilostane administration controlled pituitary-dependent hyperadrenocorticism in these dogs. It was safe, effective and free of side-effects at the doses used. Most dogs were initially quite sensitive to the drug for 10 to 30 days, then required higher doses until a prolonged phase of stable dose requirements occurred. Urinary corticoid:creatinine ratio was useful in assessing duration of drug effect. Some dogs treated for more than 2 years required reduction or temporary cessation of drug because of iatrogenic hypoadrenocorticism. [source] Mechanism of prolonged vasorelaxation to ATP in the rat isolated mesenteric arterial bedBRITISH JOURNAL OF PHARMACOLOGY, Issue 3 2001Vera Ralevic This study investigated the mechanism of prolonged relaxation to ATP in the rat isolated perfused mesenteric arterial bed. In methoxamine pre-constricted preparations, ATP elicited dose-dependent, endothelium-dependent, rapid relaxation at 5 pmol , 0.05 ,mol (Rmax 76±5.6%, pD2 9.2±0.2), and contraction, followed by prolonged endothelium-independent vasorelaxation at 0.05, 0.5 and 5 ,mol (56±3.0, 87±2.9 and 85±4.6%). Suramin (100 ,M), attenuated rapid (pD2 7.8±0.1) and prolonged relaxation to ATP. The selective P2 receptor antagonist PPADS (10 ,M) reduced prolonged, but not rapid relaxation. Neither phase of relaxation was affected by 8-sulphophenyltheophylline (1 ,M) or indomethacin (10 ,M). ,,,-methylene ATP (,,,-meATP; 10 ,M) attenuated prolonged relaxation to ATP (relaxations at 0.05 and 0.5 ,mol were 25±8.3 and 48±9.0%, respectively). ,,,-meATP blocked contractions and revealed rapid relaxation to ATP at 0.05 , 5 ,mol. Capsaicin pre-treatment did not affect either phase of vasorelaxation to ATP. ,,,-meATP (10 ,M) had no effect on vasorelaxation mediated by electrical stimulation of capsaicin-sensitive sensory nerves. High K+ (25 mM) attenuated prolonged relaxation to ATP (21±2.6 and 64±5.8%, at 0.05 and 0.5 ,mol, respectively), but had no effect on rapid relaxation. Ouabain (1 mM), an inhibitor of Na+/K+ -ATPase, and glibenclamide (10 ,M), an inhibitor of KATP channels, also attenuated prolonged relaxation to ATP. Charybdotoxin (100 nM), a selective inhibitor of KCa channels, and tetraethylammonium (10 mM) had no effect on rapid or prolonged relaxations. These results show that the prolonged phase of vasorelaxation to ATP in the rat isolated mesenteric arterial bed, which may be mediated by P2Y receptors, is endothelium-independent, involves activation of Na+/K+ -ATPase and KATP channels, and is inhibited by ,,,-meATP. Neither prolonged nor rapid vasorelaxation to ATP involves capsaicin-sensitive sensory nerves, adenosine P1 receptors, prostanoids or KCa channels. British Journal of Pharmacology (2001) 132, 685,692; doi:10.1038/sj.bjp.0703868 [source] |