Search results for "Mechanism"

Myogenic effects enhance norepinephrine constriction: Inhibition by nitric oxide and felodipine

1998

Myogenic effects enhance norepinephrine constriction: Inhibition by nitric oxide and felodipine. Myogenic, pressure-induced vasoconstriction may amplify the effects of circulating vasoconstrictors. Through intravital microscopy in cremaster arterioles (31 to 115 μm diameter), the relative contribution of myogenic responses (MR) to norepinephrine (NE)-induced constriction and the inhibitor potency of nitric oxide (NO) or a Ca2+ entry blocker (CEB), felodipine (F), were examined. In 24 anesthetized hamsters, a vessel occluder was placed around the aorta to control cremaster vessel inflow pressure (IP). NE infusion increased blood pressure (by 50 ± 2mm Hg) and induced significant constriction …

Tutorial in oral antithrombotic therapy: biology and dental implications.

2013

Objectives: Recent developments of new direct oral anticoagulants that target specific clotting factors necessitate understanding of coagulation biology. The objective of this tutorial is to offer dental professionals a review of coagulation mechanisms and the pharmacodynamics of the conventional and new oral anticoagulants. Also, we summarized the dental implications of the conventional and new anticoagulants. Method: We searched Medline using search terms “antithrombotic”, “antihemostasis” or “anticoagulation” and combined them with the search results of “dental”, “oral surgery” or “periodontal”. We restricted the results to “human” and “English”. Results: The early coagulation cascade, t…

Measurement of coagulation factors during rivaroxaban and apixaban treatment: Results from two crossover trials

2018

Abstract Background Prediction models for venous thromboembolism recurrence will likely be improved by adding levels of coagulation factors. Risk assessment is ideally performed during anticoagulant treatment, however, the influence of direct oral anticoagulants on coagulation factors is uncertain. Objective To assess the influence of rivaroxaban and apixaban on several coagulation factor levels. Methods In two crossover trials we assessed the influence of rivaroxaban and apixaban intake on factor (F)VIII, FXI and FXII‐activity and fibrinogen, von Willebrand factor (VWF:Ag), and d‐dimer levels. At three sessions with a washout period in between, blood was taken from 12 healthy male individu…

Cigarette smoke-induced pulmonary endothelial dysfunction is partially suppressed by sildenafil.

2009

Abstract Cigarette smoke mediated oxidative stress and endothelial dysfunction are important processes in the pathogenesis of several lung disorders. In this study we evaluated the effect of PDE5 inhibition on pulmonary artery endothelial dysfunction induced by cigarette smoke in vitro . Human pulmonary artery endothelial cells (HPAEC) were incubated in the absence or presence of PDE5 inhibitor sildenafil (10 nM–1 μM), PKG agonist 8-Br-cGMP (1 mM), or the antioxidants dyphenyleneiodonium (DPI 1 μM) and N -acetylcysteine (NAC 1 mM) for 30 min. Then, cigarette smoke extract (CSE) was added for 24 h. CSE (2.5–10%)-induced ROS generation was suppressed by DPI, and partially reversed by sildenaf…

2020

Background. Anticoagulant therapy, the cornerstone treatment in acute venous thromboembolism (VTE), strongly impacts thrombin generation (TG). Until now, the appearance of the TG curve in platelet rich plasma (PRP) from patients with acute VTE has not been investigated. Methods. We analyzed the shape of TG curves measured in PARP of 180 acute VTE patients. Results. Normal shape of TG curves was observed in 110 patients, 50 patients showed no TG and 20 patients showed biphasic TG curve. The linear regression analysis, adjusted for age, sex, VTE clinical phenotypes and therapy showed that the appearance of biphasic curves is significantly associated with female sex, presence of cancer and the…

The Potential Use of Resveratrol for Cancer Prevention.

2019

In addition to the traditional treatments of cancer and cancer prevention, the use of natural compounds, especially those found in food, should be considered. To clarify if resveratrol has the potential for cancer prevention and the possibility of use in therapy, the following must be taken into account: data from epidemiology, clinical protocol (case and control), preclinical studies (lab animals), use of established cell lines as models of cancer cells, test tube assays (enzymes activities), and requirements of nanotechnologies in order to discover new drugs to fight cancer. From this perspective and future expected advances, more information is needed such as improved efficacy, methods o…

Nitric oxide and sensory afferent neurones modulate the protective effects of low-dose endotoxin on rat gastric mucosal damage

1995

Pretreatment (1 h) with low doses (5-40 micrograms/kg i.p.) of Escherichia coli endotoxin dose dependently reduced the gastric mucosal damage induced by a 10 min challenge with 1 ml ethanol (50% and 100%) in conscious rats. Treatment with the nitric oxide synthesis inhibitor, NG-nitro-L-arginine methyl ester (L-NAME, 5 and 10 mg/kg i.p.), significantly inhibited the protective effects of endotoxin (40 micrograms/kg i.p.). The actions of L-NAME were reversed by the prior administration of L-arginine (100 mg/kg i.p.). The protective effects of endotoxin were not influenced by pretreatment with dexamethasone (5 mg/kg s.c. twice) or indomethacin (5 mg/kg s.c.). However, ablation of sensory affe…

A pyrroloquinazoline derivative with anti-inflammatory and analgesic activity by dual inhibition of cyclo-oxygenase-2 and 5-lipoxygenase

2002

Abstract In a previous study, we reported a new pyrroloquinazoline derivative, 3-(4′-acetoxy-3′,5′-dimethoxy)benzylidene-1,2-dihydropyrrolo[2,1- b ]quinazoline-9-one (PQ), which inhibited human purified 5-lipoxygenase activity and prostaglandin E 2 release in lipopolysaccharide-stimulated RAW 264.7 cells. In the present work, we show that PQ inhibits cyclo-oxygenase-2 activity in intact cell assays (human monocytes) and purified enzyme preparations (ovine isoenzymes) without affecting cyclo-oxygenase-1 activity. This behaviour was confirmed in vivo by using the zymosan-injected mouse air pouch model, where PQ caused a marked reduction in cell migration and leukotriene B 4 levels at 4 h, as …

Neural Mechanisms of Acceptance and Commitment Therapy for Chronic Pain: A Network-Based fMRI Approach

2021

AbstractOver 100 million Americans suffer from chronic pain (CP), which causes more disability than any other medical condition in the U.S. at a cost of $560-$635 billion per year (IOM, 2011). Opioid analgesics are frequently used to treat CP. However, long term use of opioids can cause brain changes such as opioid-induced hyperalgesia that, over time, increase pain sensation. Also, opioids fail to treat complex psychological factors that worsen pain-related disability, including beliefs about and emotional responses to pain. Cognitive behavioral therapy (CBT) can be efficacious for CP. However, CBT generally does not focus on important factors needed for long-term functional improvement, i…

Impairment in Theory of Mind in Parkinson's Disease Is Explained by Deficits in Inhibition

2019

Objective: Several studies have reported that people with Parkinson's disease (PD) perform poorly on tests of Theory of Mind' (ToM), suggesting impairment in the ability to understand and infer other people's thoughts and feelings. However, few studies have sought to separate the processes involved in social reasoning from those involved in managing the inhibitory demands on these tests. In this study, we investigated the contribution of inhibition to ToM performance in PD. Methods. 18 PD patients and 22 age-matched healthy controls performed a ToM test that separates the ability to infer someone else's perspective from the ability to inhibit one's own. Participants also completed a battery…