1,720,991 research outputs found
Estrogen induces nitric oxide production via nitric oxide synthase activation in endothelial cells.
No full textINTRODUCTION
17β-estradiol (E2) has been found to induce vasodilation in the cardiovascular system and at physiological levels, resulting in prevention of cerebral vasospasm following subarachnoid hemorrhage (SAH) in animal models. The goal of this study was to analyze the cellular mechanism of nitric oxide (NO) production and its relation to E2, in vitro in brain and peripheral endothelial cells.
METHODS
Human umbilical endothelial cells (HUVEC) and brain endothelial cells (bEnd.3) were treated with estradiol (E2, 0.1, 10, 100, and 1,000 nM), and supernatant was collected at 0, 5, 15, 30, 60, and 120 min for nitric oxide metabolome (nitrite, NO₂) measurements. Cells were also treated with E2 in the presence of 1400W, a potent eNOS inhibitor, and ICI, an antagonist of estradiol receptors (ERs). Effects of E2 on eNOS protein expression were assessed with Western blot analysis.
RESULTS
E2 significantly increased NO2 levels irrespective of its concentration in both cell lines by 35 % and 42 % (p 0.05). The combination of E2 (10 nM) and a NOS inhibitor (1400W, 5 μM) inhibited NO2 increases in addition (4 %, p > 0.05). E2 induced increases in eNOS protein levels and phosphorylated eNOS (eNOS(p)).
CONCLUSIONS
This study indicates that E2 induces NO level increases in cerebral and peripheral endothelial cells in vitro via eNOS activation and through E2 receptor-mediated mechanisms. Further in vivo studies are warranted to evaluate the therapeutic value of estrogen for the treatment of SAH-induced vasospasm
Blood Clot Placement Model of Subarachnoid Hemorrhage in Non-human Primates
No full textDespite ongoing extensive and promising research to prevent and treat cerebrovascular vasospasm and delayed ischemic neurological deficits (DIND) after aneurysmal subarachnoid hemorrhage (aSAH), clinical outcomes remain unsatisfying. Neuroprotective strategies developed in basic science research laboratories need to be translated from bench-to-bedside using appropriate animal models. While a primate model is widely accepted as the best animal model mimicking development of delayed cerebral vasospasm after aSAH, its worldwide usage has dramatically decreased because of ethical and financial limitations. However, the use of primate models of subarachnoid hemorrhage (SAH) remains a recommended bridge for translation of early preclinical studies in rodents to human clinical trials. This paper discusses the technical aspects as well as advantages and disadvantages of a blood clot placement model of subarachnoid hemorrhage in non-human primates.
Keyword
Cost-effective patient-specific intraoperative molded cranioplasty
No full textIntraoperative molding of polymethyl-methacrylate into complex three-dimensional shapes with correct thickness is often a time-consuming process and may lead to unsatisfying cosmetical results. This article describes an intraoperative technique to assemble a polymethyl-methacrylate implant as a replica of the patient's bone flap. This approach provides a fast and inexpensive alternative technique with good cosmetic outcome. The technique is feasible and can be applied in early and delayed cranioplasty procedures. In selected patients, immediate single-stage reconstruction avoids a second operation
Mouse Model of Subarachnoid Hemorrhage: Technical Note on the Filament Perforation Model
No full textExperiments using genetically engineered mice are regarded as indispensable to gaining a better understanding of the molecular pathophysiology in neuronal injury after subarachnoid hemorrhage (SAH). Therefore, mouse SAH models are becoming increasingly important. The circle of Willis perforation (cWp) model is the most frequently used mouse SAH model. We report and discuss the technical surgical approach, results, and difficulties associated with the cWp model, with reference to the existing literature. Our results largely confirmed previously published results. This model may be the first choice at present, because important pathologies can be reproduced in this model and most findings in the literature are based on it
Primary reconstruction of open depressed skull fractures with titanium mesh
No full textOpen skull fractures have been traditionally managed in 2 stages: urgent craniotomy and elevation of the fracture with removal of contaminated bone, debridement, and delayed cranioplasty. Primary, single-stage repair of these injures has been said to entail risks such as infections. Recent experience, however, disproved these concerns.We used a primary single-stage reconstruction for patients presenting with open depressed skull fractures. All patients received antibiotic prophylaxis. The patients underwent elevation of the compound fracture and craniotomy if necessary. Debridement was performed, followed by skull reconstruction using a 0.6-mm titanium mesh.We present 5 consecutive male patients (age, 32.2 +/- 15.6 years) who underwent primary reconstruction of open depressed skull fractures. Clinical and radiologic follow-up was performed 2 months after surgery. The duration of the surgery was 2 +/- 1.6 hours. The size of the implanted mesh was 13 +/- 13.1 cm. No infection was detected in our series, with a follow-up period of 22 +/- 6.5 months (range, 16-29 months). The cosmetic result was defined in 4 patients as "excellent" and in 1 patient as "good."Primary reconstruction of open skull fractures with titanium mesh is feasible, safe, and cosmetically preferable than the conventional staged approach. The introduction into clinical practice can be warranted
Intracranial Aneurysm Rupture Is Predicted by Measures of Solar Activity.
No full textOBJECTIVE
The cause precipitating intracranial aneurysm rupture remains unknown in many cases. It has been observed that aneurysm ruptures are clustered in time, but the trigger mechanism remains obscure. Because solar activity has been associated with cardiovascular mortality and morbidity, we decided to study its association to aneurysm rupture in the Swiss population.
METHODS
Patient data were extracted from the Swiss SOS database, at time of analysis covering 918 consecutive patients with angiography-proven aneurysmal subarachnoid hemorrhage treated at 7 Swiss neurovascular centers between January 1, 2009, and December 31, 2011. The daily rupture frequency (RF) was correlated to the absolute amount and the change in various parameters of interest representing continuous measurements of solar activity (radioflux [F10.7 index], solar proton flux, solar flare occurrence, planetary K-index/planetary A-index, Space Environment Services Center [SESC] sunspot number and sunspot area) using Poisson regression analysis.
RESULTS
During the period of interest, there were 517 days without recorded aneurysm rupture. There were 398, 139, 27, 12, 1, and 1 days with 1, 2, 3, 4, 5, and 6 ruptures per day. Poisson regression analysis demonstrated a significant correlation of F10.7 index and RF (incidence rate ratio [IRR] = 1.006303; standard error (SE) 0.0013201; 95% confidence interval (CI) 1.003719-1.008894; P < 0.001), according to which every 1-unit increase of the F10.7 index increased the count for an aneurysm to rupture by 0.63%. A likewise statistically significant relationship of both the SESC sunspot number (IRR 1.003413; SE 0.0007913; 95% CI 1.001864-1.004965; P < 0.001) and the sunspot area (IRR 1.000419; SE 0.0000866; 95% CI 1.000249-1.000589; P < 0.001) emerged. All other variables analyzed showed no significant correlation with RF.
CONCLUSIONS
We found greater radioflux, SESC sunspot number, and sunspot area to be associated with an increased count of aneurysm rupture. The clinical meaningfulness of this statistical association must be interpreted carefully and future studies are warranted to rule out a type-1 error
Intraoperative Patient-Specific Reconstruction of Partial Bone Flap Defects After Convexity Meningioma Resection
No full textOBJECTIVE: To evaluate implant accuracy and cosmetic outcome of a new intraoperative patient-specific cranioplasty method after convexity meningioma resection. METHODS: The patient's own bone flap served as a template to mold a negative form with the use of polymethyl methacrylate (PMMA). The area of bone invasion was determined and broadly excised under white light illumination with a safety margin of at least 1 cm. The definitive replica was cast within the remaining bone flap frame and the imprint. Clinical and radiologic follow-up examinations were performed 3 months after surgery. RESULTS: Four women and two men (mean age 51.4 years ± 12.8) underwent reconstruction of bone flap defects after meningioma resection. Mean duration of intraoperative reconstruction of the partial bone flap defects was 19 minutes ± 4 (range 14-24 minutes). Implant sizes ranged from 17-35 cm(2) (mean size 22 cm(2) ± 8). Radiologic and clinical follow-up examinations revealed excellent implant alignment and favorable cosmesis (visual analogue scale for cosmesis [VASC] = 97 ± 5) in all patients. CONCLUSIONS: Patient-specific reconstruction of partial bone flap defects after convexity meningioma resection using the presented intraoperative PMMA cast method resulted in excellent bony alignment and a favorable cosmetic outcome. Relatively low costs and minimized operation time for adjustment and insertion of the cranioplasty implant justify use of this method in small bony defects as well
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