Role of p44/p42 MAP kinase in the age-dependent increase in vascular smooth muscle cell proliferation and neointimal formation.
(1/33)
OBJECTIVE: Age-dependent increase in vascular smooth muscle cell (VSMC) proliferation is thought to contribute to the pathology of atherosclerotic diseases. In this study, we investigated the role of mitogen-activated protein kinases (MAPKs) on VSMC proliferation and neointimal formation in the context of aging. METHODS AND RESULTS: VSMCs were isolated from the aorta of young and old rabbits. The proliferative index after serum stimulation was significantly increased in old versus young VSMCs. This was associated with a significant and specific age-dependent increase in p44/p42 MAPK activation. Treatment with MEK inhibitor PD98059 successfully inhibited p44/p42 MAPK activities and VSMC proliferation. These results were confirmed in vivo using a model of balloon injury in rabbit iliac arteries. p44/p42 MAPK activities were rapidly induced by angioplasty in young and old animals. However, the levels of p44/p42 MAPK activities achieved in arteries of old rabbits were significantly higher than those of young rabbits. This was associated with a higher cellular proliferative index and a significant increase in neointimal formation in old animals. Local delivery of PD98059 in old rabbits successfully inhibited p44/p42 MAPK activities after angioplasty, which led to a significant reduction in cellular proliferation and neointimal formation in treated animals. CONCLUSIONS: Our study suggests for the first time that increased p44/p42 MAPK activation contributes to augmented VSMC proliferation and neointimal formation with aging. p44/p42 MAPK inhibition could represent a novel therapeutic avenue against atherosclerotic diseases. (+info)
Selective hippocampal lesions do not increase adrenocortical activity.
(2/33)
It has been proposed that the hippocampus exerts a tonic inhibitory influence on the hypothalamic-pituitary-adrenal (HPA) stress axis. This claim rests, in particular, on the upregulation of corticosterone secretion and other measures of HPA activity after nonselective lesions of the hippocampal formation. We measured plasma corticosterone concentrations after selective neurotoxic damage to the hippocampus and the subiculum in rats. Concentrations were estimated during rest in the rat's home cage and at several time points after varying degrees of stress. Lesions of the hippocampus did not increase the concentration of corticosterone relative to control rats in any condition. Temporary inactivation of the hippocampus or the ventral subiculum by infusion of the GABAA receptor agonist muscimol also failed to induce hypersecretion, although hippocampal infusions did impair spatial memory. These results suggest that the hippocampus is not necessary for tonic inhibition of adrenocortical activity and imply that the HPA axis receives efficient negative feedback inhibition from other brain systems too. (+info)
Trans-Tenon's retrobulbar triamcinolone infusion for the treatment of uveitis.
(3/33)
AIM: To assess efficacy and complications of trans-Tenon's retrobulbar infusion of triamcinolone acetonide for posterior uveitic inflammation. METHODS: Non-randomised, uncontrolled, retrospective study of 51 eyes of 37 patients who underwent triamcinolone infusion for vitritis, cystoid macular oedema (CMO), or posterior retinal vasculitis using a long blunt cannula via an incision made through conjunctiva and Tenon's capsule. RESULTS: Overall clinical efficacy was 86%; 96% for vitritis, 82% for CMO, and 33% for posterior retinal vasculitis. Mean visual acuity improved within 1 month after triamcinolone infusion (p <0.05). Cataract progression and intraocular pressure elevation were observed in 31% and 27% of eyes, respectively. CONCLUSION: Trans-Tenon's retrobulbar triamcinolone infusion may be a safe and effective treatment for posterior uveitic inflammation. (+info)
Pharmacokinetics and efficacy of ropivacaine continuous wound instillation after joint replacement surgery.
(4/33)
BACKGROUND: As continuous wound instillation with local anaesthetic has not been evaluated after hip/knee arthroplasties, our study was designed to determine whether this technique could enhance analgesia and improve patient outcome after joint replacement surgery. METHODS: Thirty-seven patients undergoing elective hip/knee arthroplasties under spinal block were randomly assigned to two analgesia groups. Group M received continuous i.v. infusion of morphine plus ketorolac for 24 h. Then, a multi-hole 16 G catheter was placed subcutaneously and infusion of saline was maintained for 55 h. Group R received i.v. saline. Thereafter the wound was infiltrated with a solution of ropivacaine 0.5% 40 ml, then a multi-hole 16 G catheter was placed subcutaneously and an infusion of ropivacaine 0.2% 5 ml h(-1) was maintained for 55 h. Visual analogue scale scores were assessed at rest and on passive mobilization by nurses blinded to analgesic treatment. Total plasma ropivacaine concentration was measured. RESULTS: Group R showed a significant reduction in postoperative pain at rest and on mobilization, while rescue medication requirements were greater in Group M. Total ropivacaine plasma concentration remained below toxic concentrations and no adverse effects occurred. Length of hospital stay was shorter in Group R. CONCLUSION: Infiltration and wound instillation with ropivacaine 0.2% is more effective in controlling postoperative pain than systemic analgesia after major joint replacement surgery. (+info)
A novel method for viral gene delivery in solid tumors.
(5/33)
Intratumoral infusion is the most commonly used method for viral gene delivery in clinical trials for cancer treatment. However, a potential problem in this approach is that viral vectors may disseminate from tumor to normal tissues during and after the infusion. To reduce the dissemination, we developed a novel method based on a biocompatible polymer, poloxamer 407, which could significantly increase the viscosity of virus suspension when the temperature was changed from 4 degrees C to 37 degrees C. With this method, we could significantly increase transgene expression in solid tumors and reduce virus dissemination by 2 orders of magnitude after intratumoral infusion of adenoviral vectors. The mechanism of reduction was likely to be that the viscous poloxamer solution blocked convection of viral vectors in the interstitial space and the lumen of microvessels in the vicinity of the infusion site. This method has a potential to be used in the clinic for enhancing efficacy and reducing toxicity in viral gene therapy. (+info)
Docosahexaenoic acid-induced amelioration on impairment of memory learning in amyloid beta-infused rats relates to the decreases of amyloid beta and cholesterol levels in detergent-insoluble membrane fractions.
(6/33)
We investigated the effects of dietary administration of docosahexaenoic acid (DHA; C22:6n-3) on the levels of amyloid beta (A beta) peptide (1-40) and cholesterol in the nonionic detergent Triton 100 x-insoluble membrane fractions (DIFs) of the cerebral cortex and, also, on learning-related memory in an animal model of Alzheimer's disease (AD) rats infused with A beta peptide (1-40) into the cerebral ventricle. The infusion increased the levels of A beta peptide and cholesterol in the DIFs concurrently with a significant increase in reference memory errors (measured by eight-arm radial-maze tasks) compared with those of vehicle rats. Conversely, the dietary administration of DHA to AD-model rats decreased the levels of A beta peptide and cholesterol in the DIFs, with the decrease being more prominent in the DHA-administered rats. Regression analysis revealed a significant positive correlation between A beta peptide and each of cholesterol, palmitic acid and stearic acid, and between the number of reference memory errors and each of cholesterol, palmitic, stearic and oleic acid; moreover, a significant negative correlation was observed between the number of reference memory errors and the molar ratio of DHA to palmitic plus stearic acid. These results suggest that DHA-induced protection of memory deficits in AD-model rats is related to the interactions of cholesterol, palmitic acid or stearic acid with A beta peptides in DIFs where DHA ameliorates these interactions. (+info)
A quantitative, randomized study evaluating three methods of mesenchymal stem cell delivery following myocardial infarction.
(7/33)
AIMS: Mesenchymal stem cells (MSCs), rare bone marrow-derived stem cell precursors of non-haematopoietic tissues, have shown promise in potentially repairing infarcted myocardium. These and similar cell types are being tested clinically, but understanding of delivery and subsequent biodistribution is lacking. This study was designed to quantitatively compare MSC engraftment rates after intravenous (IV), intracoronary (IC), or endocardial (EC) delivery in a porcine myocardial infarction (MI) model. METHODS AND RESULTS: Allogeneic, male MSCs were cultured from porcine bone marrow aspirates. Iridium nanoparticles were added during culturing and internalized by the MSCs. An MI was induced in female swine (27-40 kg in size) by prolonged balloon occlusion of the mid-left anterior descending artery. Animals (n = 6 per group) were randomized to one of three delivery methods. Cellular engraftment was determined 14+/-3 days post-delivery by measuring ex-vivo the iridium nanoparticle concentration in the infarct. Confirmation of cellular engraftment utilized both DiI and fluorescence in situ hybridization (FISH) labelling techniques. During MSC infusion, no adverse events were noted. However, following IC infusion, half of the pigs exhibited decreased blood flow distal to the infusion site. At 14 days, the mean number of engrafted cells within the infarct zone was significantly greater (P< or =0.01) following IC infusion than either EC injection or IV infusion and EC engraftment was greater than IV engraftment (P< or =0.01). There was less systemic delivery to the lungs following [EC vs. IV (P = 0.02), EC vs. IC (P = 0.06)]. Both DiI and FISH labelling demonstrated the presence of engrafted male MSCs within the female infarcted tissue. CONCLUSION: IC and EC injection of MSCs post-MI resulted in increased engraftment within infarcted tissue when compared with IV infusion, and IC was more efficient than EC. However, IC delivery was also associated with a higher incidence of decreased coronary blood flow. EC delivery into acutely infarcted myocardial tissue was safe and well tolerated and was associated with decreased remote organ engraftment with compared with IC and IV deliveries. (+info)
Local infusion of norepinephrine reduces blood losses and need of transfusion in total knee arthroplasty.
(8/33)
Blood loss after total knee arthroplasty (TKA) is often associated with cardiovascular complications and a high transfusion rate of allogenic blood. In our study we focused our attention on developing a new intra-surgical procedure that appears safe, easy to perform and effective in the reduction of bleeding in TKA. We evaluated 84 patients who underwent TKA and met our inclusion criteria; they were assigned to two groups: 55 controls in which a saline solution was used to wash the surgical field before tourniquet release, and a second group of 29 patients, in which a saline solution containing a low dose of norepinephrine was locally applied before tourniquet release. The local administration of a low dose of norepinephrine has induced a significant reduction of perioperative blood loss and blood transfusion requirements; in addition, this method was characterised by the absence of complications or adverse effects. In conclusion, our data suggest that intraoperative local administration of a low dose of norepinephrine could represent an effective and safe method of reducing blood loss and preventing blood transfusions in patients with TKA. (+info)