Search results for "time factor"
showing 10 items of 3219 documents
In human endothelial cells rapamycin causes mTORC2 inhibition and impairs cell viability and function.
2008
Aim Drug-eluting stents are widely used to prevent restenosis but are associated with late endothelial damage. To understand the basis for this effect, we have studied the consequences of a prolonged incubation with rapamycin on the viability and functions of endothelial cells. Methods and results Human umbilical vein or aorta endothelial cells were exposed to rapamycin in the absence or in the presence of tumour necrosis factor α (TNFα). After a 24 h-incubation, rapamycin (100 nM) caused a significant cell loss associated with the increase of both apoptosis and necrosis, as quantified by propidium iodide staining, caspase 3 activity, and lactate dehydrogenase release. Rapamycin also impair…
Impact of oral contraceptive use and menstrual phases on patellar tendon morphology, biochemical composition, and biomechanical properties in female …
2013
Sex differences exist with regards to ligament and tendon injuries. Lower collagen synthesis has been observed in exercising women vs. men, and in users of oral contraceptives (OC) vs. nonusers, but it is unknown if OC will influence tendon biomechanics of women undergoing regular training. Thirty female athletes (handball players, 18–30 yr) were recruited: 15 long-term users of OC (7.0 ± 0.6 yr) and 15 nonusers (>5 yr). Synchronized values of patellar tendon elongation (obtained by ultrasonography) and tendon force were sampled during ramped isometric knee extensor maximum voluntary contraction to estimate mechanical tendon properties. Furthermore, tendon cross-sectional area and lengt…
Paclitaxel and beta-lapachone synergistically induce apoptosis in human retinoblastoma Y79 cells by downregulating the levels of phospho-Akt.
2009
Paclitaxel (PTX) and beta-lapachone (LPC) are naturally occurring compounds that have shown a large spectrum of anticancer activity. In this article we show for the first time that PTX/LPC combination induces potent synergistic apoptotic effects in human retinoblastoma Y79 cells. Combination of suboptimal doses of PTX (0.3 nM) and LPC (1.5 microM) caused biochemical and morphological signs of apoptosis at 48 h of treatment. These effects were accompanied by potent lowering in inhibitor of apoptosis proteins and by activation of Bid and caspases 3 and 6 with lamin B and PARP breakdown. PTX/LPC combination acted by favoring p53 stabilization through a lowering in p-Akt levels and in ps166-MDM…
Inhibitory influence of chromogranin A N-terminal fragment (vasostatin-1) on the spontaneous contractions of rat proximal colon
2005
Very little is known about the role played by CGA and its fragments in the gastrointestinal physiology. We have studied the role of CGA N-terminal fragments in the regulation of intestinal smooth muscle contractility by measuring the influence of recombinant CGA 1-78 (VS-1) and synthetic CGA 7-57 peptides on the spontaneous mechanical activity of rat proximal colon in vitro. The mechanical activity was recorded as changes in the intraluminal pressure. VS-1 (0.1-30 nM) and CGA 7-57 (10-300 nM) produced concentration-dependent inhibitory effects, characterized by a progressive decrease in the mean amplitude of circular muscle spontaneous contractions, without affecting the resting tone. The r…
Medullary respiratory-related neurons with axonal connections to rostral pons and their function in termination of inspiration.
1985
In urethane-anaesthetized, paralyzed and artificially ventilated rabbits, medullary respiration-related neurons (RRU) were classified according to the phase relation of their burst discharge to phrenic nerve activity. Phase-bound inspiratory (I) or expiratory (E) neurons were discriminated from phase-spanning expiratory-inspiratory (EI) or inspiratory-expiratory (IE) units. Mechanisms of termination of inspiration by electrical stimulation of rostral pontine nuclei (Nc. parabrachialis medialis; Lc. coeruleus) were examined firstly to demonstrate whether RRU receive descending excitatory and inhibitory afferents as well as ascending efferents and secondly to analyse the time course of the ne…
Cross-circulation and Cell Distribution Kinetics in Parabiotic Mice
2011
Blood-borne nucleated cells participate not only in inflammation, but in tissue repair and regeneration. Because progenitor and stem cell populations have a low concentration in the blood, the circulation kinetics and tissue distribution of these cells is largely unknown. An important approach to tracking cell lineage is the use of fluorescent tracers and parabiotic models of cross-circulation. Here, we investigated the cross-circulation and cell distribution kinetics of C57/B6 GFP(+)/wild-type parabionts. Flow cytometry analysis of the peripheral blood after parabiosis demonstrated no evidence for a "parabiotic barrier" based on cell size or surface characterstics; all peripheral blood cel…
Effect of temperature on the duration of sensitive period and on the number of photoperiodic cycles required for the induction of reproductive diapau…
2013
Abstract Correct timing of the induction of photoperiodic reproductive diapause has been found to play an important role in the life cycle of several northern insect species. However, even when the environmental conditions are favourable for diapause, the switch to diapause can only take place when the females are in a proper developmental and physiological stage, referred to as the sensitive period (SP) for diapause. We have previously shown that in a northern fly species, Drosophila montana, the developmental pathway of the ovaries (direct maturation vs. diapause) is determined by photoperiodic cues that the females receive after eclosion. Here, we have studied the effects of temperature …
Is rootstock-induced dwarfing in olive an effect of reduced plant hydraulic efficiency?
2006
We investigated the hydraulic architecture of young olive trees either self-rooted or grafted on rootstocks with contrasting size-controlling potential. Clones of Olea europea L. (Olive) cv ''Leccino'' inducing vigorous scion growth (Leccino ''Minerva'', LM) or scion dwarfing (Leccino ''Dwarf'', LD) were studied in different scion/rootstock combinations (LD, LM, LD/LD, LM/LM, LD/LM and LM/LD). Shoots growing on LD root systems developed about 50% less leaf surface area than shoots growing on LM root systems. Root systems accounted for 60-70% of plant hydraulic resistance (R), whereas hydraulic resistance of the graft union was negligible. Hydraulic conductance (K = 1/R) of LD root systems w…
Natural selection constrains personality and brain gene expression differences in Atlantic salmon (Salmo salar).
2015
ABSTRACT In stream-spawning salmonid fishes there is a considerable variation in the timing of when fry leave the spawning nests and establish a feeding territory. The timing of emergence from spawning nests appears to be related to behavioural and physiological traits, e.g. early emerging fish are bolder and more aggressive. In the present study, emerging Atlantic salmon (Salmo salar L.) alevins were sorted into three fractions: early, intermediate and late emerging. At the parr stage, behaviour, stress responses, hindbrain monoaminergic activity and forebrain gene expression were explored in fish from the early and late emerging fractions (first and last 25%). The results show that when s…
Use of semipermeable membrane devices for monitoring pesticides in indoor air.
2009
Abstract In this work, 40 pesticides from different categories were analyzed in the air of 20 indoor places that have an intensive use of pesticides. Passive sampling was carried out by using semipermeable membrane devices (SPMDs) deployed for 7 days. SPMDs were analyzed using microwave-assisted extraction and GC/MS. PCB-195 was used as an internal standard. Recoveries ranged between 81 and 108 for many compounds, with RSD values <11. Typical LOD values for 7 days of sampling were from 0.1 to 3.1 ng/m. Propamocarb, propoxur, carbosulfan, pirimicarb, metribuzin, metalaxyl, pendimethalin, oxadiazon, phenothrin, and permethrin were detected in 11 sampling sites, with air concentrations …