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Acute Period (acute + period)
Selected AbstractsDifferential effects of glucose on agonist-induced relaxations in human mesenteric and subcutaneous arteriesBRITISH JOURNAL OF PHARMACOLOGY, Issue 3 2008A MacKenzie Background and purpose: Acute periods of hyperglycaemia are strongly associated with vascular disorder, yet the specific effects of high glucose on human blood vessel function are not fully understood. In this study we (1) characterized the endothelial-dependent relaxation of two similarly sized but anatomically distinct human arteries to two different agonists and (2) determined how these responses are modified by acute exposure to high glucose. Experimental approach: Ring segments of human mesenteric and subcutaneous arteries were mounted in a wire myograph. Relaxations to acetylcholine and bradykinin were determined in a control (5 mM) and high glucose (20 mM) environment over a 2 and 6 h incubation period. Key results: Bradykinin-induced relaxation in both sets of vessels was mediated entirely by EDHF whilst that generated by acetylcholine, though principally generated by EDHF, also had contribution from prostacyclin and possibly nitric oxide in mesenteric and subcutaneous vessels, respectively. A 2-h incubation of high glucose impaired bradykinin-induced relaxation of subcutaneous vessels whilst, in contrast, the relaxation generated by bradykinin in mesenteric vessels was enhanced at the same time point. High glucose significantly augmented the relaxation generated by acetylcholine in mesenteric and subcutaneous vessels at a 2 and 6 h incubation point, respectively. Conclusions and implications: Short periods of high glucose exert a variable influence on endothelial function in human isolated blood vessels that is dependent on factors of time, agonist-used and vessel studied. This has implications for how we view the effects of acute hyperglycaemia found in patients with diabetes mellitus as well as other conditions. British Journal of Pharmacology (2008) 153, 480,487; doi:10.1038/sj.bjp.0707592; published online 26 November 2007 [source] Hippocampal vulnerability following traumatic brain injury: a potential role for neurotrophin-4/5 in pyramidal cell neuroprotectionEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2006N. C. Royo Abstract Traumatic brain injury (TBI) causes selective hippocampal cell death, which is believed to be associated with cognitive impairment observed both in clinical and experimental settings. Although neurotrophin administration has been tested as a strategy to prevent cell death following TBI, the potential neuroprotective role of neurotrophin-4/5 (NT-4/5) in TBI remains unknown. We hypothesized that NT-4/5 would offer neuroprotection for selectively vulnerable hippocampal neurons following TBI. Measurements of NT-4/5 in rats subjected to lateral fluid percussion (LFP) TBI revealed two,threefold increases in the injured cortex and hippocampus in the acute period (1,3 days) following brain injury. Subsequently, the response of NT-4/5 knockout (NT-4/5,/,) mice to controlled-cortical impact TBI was investigated. NT-4/5,/, mice were more susceptible to selective pyramidal cell loss in Ahmon's corn (CA) subfields of the hippocampus following TBI, and showed impaired motor recovery when compared with their brain-injured wild-type controls (NT-4/5wt). Additionally, we show that acute, prolonged administration of recombinant NT-4/5 (5 µg/kg/day) prevented up to 50% of the hippocampal CA pyramidal cell death following LFP TBI in rats. These results suggest that post-traumatic increases in endogenous NT-4/5 may be part of an adaptive neuroprotective response in the injured brain, and that administration of this neurotrophic factor may be useful as a therapeutic strategy following TBI. [source] Long-lasting increased excitability differs in dentate gyrus vs.HIPPOCAMPUS, Issue 3 2002CA1 in freely moving chronic epileptic rats after electrically induced status epilepticus Abstract A paired-pulse (PP) stimulation protocol was used to examine changes in field potentials (fEPSPs), locally evoked in CA1 via Schaffer/commissural fiber stimulation and in the dentate gyrus (DG) through angular bundle stimulation, in freely moving epileptic rats. This epilepsy model is characterized by recurrent spontaneous seizures that occur after a latent period of 1,2 weeks following an electrically induced status epilepticus (SE). In the control period, i.e., before induction of SE, the PP stimulation protocol given at the appropriate intensity evoked fEPSPs with a pronounced paired-pulse depression (PPD). In the acute period, immediately after SE, the fEPSPs in the CA1 and DG areas were generally depressed. During the latent period in the CA1 stratum radiatum, the negative fEPSP was followed by a large positive potential that remained for the rest of the recording period. CA1 PPD, observed during the control period, was changed to paired-pulse facilitation (PPF) that remained for the rest of the recording period. Also during the latent period, a broad late component appeared in DG fEPSPs. The initial decrease in PPD was partly restored in the following weeks. Timm staining at different time points after SE showed an increase of mossy-fiber sprouting in the inner molecular layer within 6 days, which was robust within 6 weeks. We noted Timm granules positioned on parvalbumin immunoreactive neurons in the granule-cell layer of rats that had survived SE, suggesting that restoration of PPD could be partly due to reinnervation of a population of GABAergic neurons. The broad late component of DG fEPSPs, which was sensitive to the NMDA receptor antagonist ketamine, was still present for at least 6 weeks into the chronic epileptic phase, indicating lasting increased excitability. These observed changes indicate a lasting increased excitability in CA1 and DG networks that could play a role in the recurrence of spontaneous seizures. Hippocampus 2002;12:311,324. © 2002 Wiley-Liss, Inc. [source] Long-term study of fluticasone propionate aqueous nasal spray in acute and maintenance therapy of nasal polyposisALLERGY, Issue 6 2009R. Jankowski Background:, Topical steroids are first-line medication to control nasal polyposis (NP), a disease with long-term clinical course. Objective:, The aim of this study was to evaluate the efficacy and safety of fluticasone propionate aqueous nasal spray (FPANS) 200 ,g twice a day (bd) after 1 month of treatment, and to compare FPANS 200 ,g bd and FPANS 200 ,g once a day (od) in maintenance and long-term treatment. Methods:, Double-blind, placebo-controlled, 8-month study with three treatment periods (1-month acute period followed with 1-month maintenance period and 6-month follow-up period) was carried out. Group 1 received FPANS 200 ,g bd, during acute, maintenance and follow-up periods, Group 2 received FPANS 200 ,g bd during acute period and FPANS 200 ,g od during maintenance and follow-up periods, and Group 3 received placebo during acute and maintenance periods and FPANS 200 ,g bd during follow-up period. Endpoints were change from baseline in clinic peak nasal inspiratory flow (PNIF), domiciliary evening PNIF, intensity of symptoms and polyposis grade. Results:, After acute period and maintenance periods, FPANS 200 ,g bd was significantly more effective than placebo on all endpoints and more effective than FPANS 200 ,g od after 1-month maintenance period on clinic PNIF, evening PNIF, obstruction, percentage of days with no sense of smell and percentage of nights with no disturbances. The two doses were similar on other endpoints. After the 6-month follow-up period, there was no difference between the two doses of FPANS at all efficacy endpoints. The safety profile of FPANS did not highlight any new or unanticipated adverse events. Conclusion:, The study demonstrated the efficacy of FPANS 200 ,g bd in acute treatment and FPANS 200 ,g od as a sufficient dose to maintain a long-term efficacy in the treatment for NP. [source] Time-dependent Variations in Ischemia-modified Albumin Levels in Mesenteric IschemiaACADEMIC EMERGENCY MEDICINE, Issue 6 2009Abdulkadir Gunduz MD Abstract Objectives:, The objective was to determine the value of ischemia-modified albumin (IMA) in the diagnosis of mesenteric embolism. The authors investigated whether or not plasma IMA levels rose in the acute period in a rat model of mesenteric ischemia and the related time-dependent changes. Methods:, In this randomized, controlled, nonblinded trial, 36 mature female Wistar rats were divided into six groups: three control (Groups I, III, and V) and three ischemia (Groups II, IV, and VI). In the control groups, blood was sampled at 30 minutes (Group I), 2 hours (Group III), and 6 hours (Group V) following a simple laparotomy. In the ischemia groups, following laparotomy, the superior mesenteric artery (SMA) was clamped using a bulldog clamp, and blood samples were taken at 30 minutes (Group II), 2 hours (Group IV), and 6 hours (Group VI). Results:, Plasma IMA levels in the ischemia groups were significantly higher compared to those of the control groups (p < 0.004). In addition, levels were higher in the 6-hour blood samples of the ischemia group than in the 2-hour and 30-minute samples (p < 0.001). Serum IMA was also higher in the 2-hour blood samples of the ischemia group than in the 30-minute samples (p < 0.001). Conclusions:, These preliminary findings suggest that serum IMA levels may represent a significant parameter in the early diagnosis of acute mesenteric ischemia and that further studies are necessary. [source] | |||||||||||||