Publications by authors named "Halvorsen S"
Article Synopsis
- Exposure to cadmium, mercury, and rotenone leads to mitochondrial dysfunction that inhibits Jak/STAT signaling in human BE(2)-C neuroblastoma cells, causing reduced cellular response to growth factors and cytokines.
- In contrast, similar exposure does not affect Jak/STAT signaling in HepG2 hepatoma cells, suggesting a protective mechanism against oxidative stress in non-neuronal cells.
- The study indicates that mitochondrial dysfunction increases reactive oxygen species production, which directly inhibits Jak tyrosine kinase activity in neurons, while antioxidant treatments can reverse these effects.
Objectives: Women with acute myocardial infarction (AMI) previously received less invasive evaluation and experienced higher mortality than men. After improvements in AMI care it is unclear whether gender differences still exist in management and outcome of AMI.
Methods: All patients admitted to Ullevål University Hospital for AMI during 2006 and 2007 were included in this cohort study.
Article Synopsis
- The study examined the role of cardiac troponin T (cTnT) levels measured on the third morning after a ST-segment elevation myocardial infarction (STEMI) in predicting the size of the heart attack and left ventricular function.
- Linear regression analysis indicated a strong correlation between cTnT levels and infarct size, while a weaker, inverse relationship existed between cTnT levels and left ventricular ejection fraction (LVEF).
- The findings suggest that cTnT measurements may help assess the extent of heart damage and could be useful in identifying patients at risk for decreased heart function.
In coronary artery bypass grafting there is a risk of graft occlusion which may result in myocardial infarction. A three-axis acceleration sensor may give additional information about heart function during surgery and the first postoperative days. This paper describes the assembly and packaging of a three-axis micro acceleration sensor for use in clinical trials.
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- The NORDISTEMI trial investigates treatment strategies for STEMI patients in rural areas where timely PCI isn't feasible, comparing immediate transfer for coronary angiography versus conservative management after thrombolysis.
- The study involves 266 patients who receive thrombolysis, with the primary endpoint being the incidence of major complications like death or reinfarction after one year.
- As of April 2006, 109 patients were randomized, with 52% receiving thrombolysis pre-hospital, and results are anticipated in 2008.
We have used acceleration sensors to monitor the heart motion during surgery. A three-axis accelerometer was made from two commercially available two-axis sensors, and was used to measure the heart motion in anesthetized pigs. The heart moves due to both respiration and heart beating.
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- Mercury is a powerful neurotoxin that can disrupt neurological development in newborns and might contribute to neurodegenerative diseases by affecting neuronal signaling pathways.
- Research showed that divalent mercury (HgCl(2)) decreases activation of important signaling pathways (Jak/STAT) needed for neuron survival, while not affecting similar pathways in non-neuronal cells.
- Oxidative stress caused by mercury treatment was similar to that caused by hydrogen peroxide, but antioxidant agents helped protect neurons from this oxidative damage, highlighting a potential mechanism for mercury's neurotoxic effects.
Cadmium blocks receptor-mediated Jak/STAT signaling in neurons by oxidative stress.
Free Radic Biol Med
August 2006
Cadmium is an environmental contaminant producing numerous pathological effects including neurological disorders. The mechanisms through which cadmium produces neurotoxicities are not completely known. We found that divalent cadmium (CdCl2) inhibited ciliary neurotrophic factor (CNTF)-mediated Jak1 and Jak2 tyrosine kinase signaling in human BE(2)-C neuroblastoma cells.
View Article and Find Full Text PDFObjectives: To study myocardial perfusion in ST-elevation myocardial infarction (STEMI) treated successfully with primary angioplasty. Additionally, to evaluate the predictive value of perfusion on subsequent infarct size.
Design: Fifty patients with acute STEMI and restoration of normal epicardial flow after primary angioplasty were included in the study.
Background: Risk assessment is integral to patient selection and counseling before coronary artery revascularization. We studied the predictive ability of cerebral magnetic resonance imaging of preoperative and postoperative cerebral ischemic injury on self-reported physical and mental health at 3 months after coronary artery bypass surgery with or without use of cardiopulmonary bypass.
Methods: In a prospective clinical trial comparing on-pump and off-pump surgery, 120 patients responded to a questionnaire for self-report of angina (Canadian Cardiovascular Society scale) and physical and mental health status (Short Form 36) at baseline before preoperative cerebral magnetic resonance imaging.
Objective: The use of aortic connector systems for proximal vein grafts in off-pump coronary artery bypass grafting might minimize aortic manipulation by eliminating the need for partial aortic clamping. The objective of this study was to asses whether use of a Symmetry connector (St Jude Medical, Inc, St Paul, Minn) reduced intraoperative cerebral embolization.
Methods: Thirty-two consecutive patients underwent off-pump coronary artery bypass grafting.
Objectives: We sought to determine the long-term cost-effectiveness of two reperfusion modalities in patients with acute ST-segment elevation myocardial infarction: primary percutaneous coronary intervention (PCI) versus thrombolytic therapy.
Design: A state-transition model that follows patients from when they develop STEMI until they die was developed. The model encompassed events and health states.
Perioperative mortality in coronary artery bypass grafting is usually caused by reduced left ventricular function due to regional myocardial ischemia or infarction. Post-operative graft occlusion is a well-known problem in coronary surgery. A sensitive tool to detect graft occlusion and monitor myocardial function may give the opportunity to revise malfunctioning grafts before departure from the hospital.
View Article and Find Full Text PDFGeneration of reactive oxygen species (ROS) with the accumulation of oxidative damage has been implicated in neurodegenerative disease and in the degradation of nervous system function with age. Here we report that ROS inhibit the activity of ciliary neurotrophic factor (CNTF) in nerve cells. Treatment with hydrogen peroxide (H(2)O(2)) as a generator of ROS inhibited CNTF-mediated Jak/STAT signaling in all cultured nerve cells tested, including chick ciliary ganglion neurons, chick neural retina, HMN-1 motor neuron hybrid cells, and SH-SY5Y and BE(2)-C human neuroblastoma cells.
View Article and Find Full Text PDFObjective: The objective of this study was to investigate the patency in saphenous vein coronary bypass grafts in which the proximal anastomoses were performed with automatic connector devices or with a traditional suture technique.
Methods: Forty-six patients underwent coronary artery bypass grafting without cardiopulmonary bypass by using one thoracic graft and one or more saphenous vein grafts. Grafts were attached to the aorta with a Symmetry connector (St Jude Medical, Inc, St Paul, Minn) in 23 patients, and partial occlusion of the aorta and sutured anastomoses were used in 23 other patients.
Article Synopsis
- A new fiber optic biosensor method is introduced for detecting signaling molecules activated by trophic factors in cells, specifically focusing on phosphorylated STAT3 in neuroblastoma cells.
- The technique utilizes a single fiber-optic probe and a 405 nm diode laser to excite the analyte, combined with a charged coupled device (CCD) spectrometer to capture the fluorescence signal.
- This new method is significantly more sensitive, offering detection capabilities that are 100 times better than traditional Western blotting techniques.
Background: Achieving reperfusion as soon as possible is essential in order to reduce myocardial infarction size and thus improve prognosis. An increasing number of patients with myocardial infarction are treated with primary percutaneous coronary intervention (PCI). Technetium 99m-tetrofosmin myocardial perfusion tomography (SPECT) is a valid test for assessing myocardium at risk and final infarct size expressed by a hypoperfusion index (HPI) of the left ventricular mass.
View Article and Find Full Text PDFIntroduction: Fibrinogen is a major determinant of plasma viscosity. The increased risk of atherothrombotic disease associated with a high fibrinogen concentration may partly be attributed to its effect on viscosity. Since the ratio between the three main fibrinogen subfractions high molecular weight (HMW)-, low molecular weight (LMW)-, and very low molecular weight (LMW')-fibrinogen is altered during acute phase conditions, and an increased HMW/LMW-fibrinogen ratio is associated with increased thromboembolic risk, we have examined how these subfractions affect viscosity.
View Article and Find Full Text PDF[Acute myocardial infarction in a young man who had been using androgenic anabolic steroids].
Tidsskr Nor Laegeforen
January 2004
Background: A few case reports suggest that the use of androgenic anabolic steroids may be associated with myocardial infarction.
Material And Methods: Case report.
Results: We report the case of a 27-year-old male body builder with acute myocardial infarction due to occlusion of the proximal left anterior descending coronary artery.
Article Synopsis
- Many cytokines use the Jak/STAT signaling pathway, allowing for interaction between different cytokine families, particularly gp130-related cytokines and IFN-gamma in the nervous system during trauma.
- IFN-gamma primarily activates STAT1 in nerve cells, but can enhance STAT3 activation when cells are pre-treated with specific factors like CNTF or interleukin-6.
- The enhanced STAT3 response is linked to ongoing protein synthesis and is influenced by inhibiting certain pathways, suggesting a complex relationship between gp130 and IFN-gamma cytokines that affects cellular responses.
Article Synopsis
- Cytokines like interferon-gamma and CNTF utilize Jak/STAT signaling pathways in nerve cells, but this activation can be quickly stopped by tyrosine phosphatase inhibitors.
- In neuroblastoma cells, using these inhibitors before cytokine exposure prevents activation of key proteins (Jak1, STAT1, STAT3), while using them afterwards disrupts normal signal decrease and keeps active proteins out of the nucleus.
- Overall, the study indicates that tyrosine phosphatases are crucial for starting Jak/STAT signaling, as their inhibition affects signaling across various cell types.