Search results for "folate"
showing 10 items of 110 documents
Linkage disequilibrium of MTHFR genotypes 677C/T-1298A/C in the German population and association studies in probands with neural tube defects(NTD).
1999
A number of studies have demonstrated that the common polymorphism 677CT in the gene encoding 5, 10-methylenetetrahydrofolate reductase (MTHFR) leads to a thermolabile variant with decreased enzyme activity and to mildly elevated plasma homocysteine. 677TT homozygosity was shown to be more frequent in NTD probands compared with controls in some studies. Recently, another polymorphism, 1298AC, in the MTHFR gene was described and combined heterozygosity 677CT/1298AC was suggested to be an additional risk factor for NTD. The present study examines the genotype and haplotype distribution of the two polymorphisms in the German population and evaluates the impact on NTD individuals and their rela…
Redox Regulation of Dihydrofolate Reductase: Friend or Troublemaker?
2015
Oxidative stress is a hallmark of cardiovascular diseases1 and a major contributor to vascular dysfunction.2 On the basis on recent concepts, vascular oxidative stress is caused mainly by infiltrating inflammatory cells such as monocytes/macrophages or leucocytes,3,4 producing so-called kindling radicals that lead to the activation of secondary, vascular enzymatic sources of reactive oxygen species (mainly superoxide).2,5 A prominent example is the uncoupled nitric oxide (NO) synthase, which means that an NO-producing antiatherosclerotic enzyme is getting switched to a superoxide-producing proatherosclerotic enzyme.2 Molecular mechanisms causing endothelial NO synthase (eNOS) uncoupling or …
Nitroglycerin-induced endothelial dysfunction and tolerance involve adverse phosphorylation and S-glutathionylation of endothelial nitric oxide synth…
2011
Continuous administration of nitroglycerin (GTN) causes tolerance and endothelial dysfunction by inducing reactive oxygen species (ROS) production from various enzymatic sources, such as mitochondria, NADPH oxidase, and an uncoupled endothelial nitric oxide synthase (eNOS). In the present study, we tested the effects of type 1 angiotensin (AT(1))-receptor blockade with telmisartan on GTN-induced endothelial dysfunction in particular on eNOS phosphorylation and S-glutathionylation sites and the eNOS cofactor synthesizing enzyme GTP-cyclohydrolase I.Wistar rats were treated with telmisartan (2.7 or 8 mg/kg per day PO for 10 days) and with GTN (50 mg/kg per day SC for 3 days). Aortic eNOS phos…
Portal Vein Thrombosis in a Preterm Newborn with Mutation of the MTHFR and PAI-1 Genes and Sepsis by Candida parapsilosis
2016
Objective This report discusses the role of both congenital and acquired risk factors in the pathogenesis of portal vein thrombosis (PVT). Study Design We describe the clinical management and treatment of PVT in a preterm newborn with a homozygous mutation of the methylenetetrahydrofolate reductase (MTHFR) and plasminogen activator inhibitor-1 (PAI-1) genes and sepsis by Candida parapsilosis. Results Although literature data suggest a minor role of genetic factors in thrombophilia in the case of only one mutation, we hypothesize that combined thrombophilic genetic defects may have a cumulative effect and significantly increase the thrombotic risk. Conclusion It could be appropriate to incl…
Thymidylate synthases from Hymenolepis diminuta and regenerating rat liver: purification, properties, and inhibition by substrate and cofactor analog…
1995
Comparative studies of thymidylate synthases, isolated from the tapeworm, Hymenolepis diminuta, and regenerating liver of its host, rat, aimed at a possibility of specific inhibition of the helminthic enzyme, are presented. While similar in structure (dimers with monomer molecular masses of 33.7 kDa and 34.9 kDa, respectively) and parameters describing interactions with substrates and products, the tapeworm and rat enzymes differed in the dependences of reaction velocity on temperature (Arrhenius plots biphasic and linear, respectively). The tapeworm, compared with the host, enzyme was less sensitive to the competitive slow-binding inhibition by 5-fluoro-dUMP and its 2-thio congener, but eq…
Homocysteine and MTHFR C677T polymorphism in children and adolescents with psychotic and mood disorders
2013
High level of homocysteine (Hcy) is risk factor of schizophrenia and mood disorders.The aim was to detect a serum level of Hcy, examine the associations between the level of Hcy, methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism and clinical properties for patients with schizophrenia, mood disorders and in a control group.There were 88 patients with schizophrenia, 28 with affective disorders and 94 from the control group. The Hamilton Anxiety Scale (HAM-A) was performed to study anxiety, the Hamilton Depression Scale (HAM-D) to study depression and the Brief Psychiatric Rating Scale (BPRS) to study severity of schizophrenia. The level of Hcy was stated by isocratic high-pe…
MTHFR C677T allelic variant is not associated to plasma and cerebrospinal fluid homocysteine in amyotrophic lateral sclerosis
2014
Amiotrophic lateral sclerosis (ALS) is a neurological disorder with a multifactorial etiopathogenesis including excitotoxicity, intracellular calcium increase and mitochondrial damage together with oxidative stress and apoptosis. Overall, the relationship between homocysteine (Hcy), motoneuron death and ALS appears to be complex and still under investigation. It has been already shown that Hcy is elevated in plasma and cerebrospinal fluid (CSF) of ALS patients, although mechanisms of hyperhomocysteinemia have not been elucidated yet. MTHFR C677T variant is the most common genetic determinant of increased homocysteinemia, but no studies regarding the effect of this polymorphism in ALS patien…
Mechanisms underlying recoupling of eNOS by HMG-CoA reductase inhibition in a rat model of streptozotocin-induced diabetes mellitus
2007
Abstract Objective HMG-CoA reductase inhibitors have been shown to upregulate GTP cyclohydrolase I (GTPCH-I), the key enzyme for tetrahydrobiopterin de novo synthesis and to normalize tetrahydrobiopterin levels in hyperglycemic endothelial cells. We sought to determine whether in vivo treatment with the HMG-CoA reductase inhibitor atorvastatin is able to upregulate the GTPCH-I, to recouple eNOS and to normalize endothelial dysfunction in an experimental model of diabetes mellitus. Methods and results In male Wistar rats, diabetes was induced by streptozotocin (STZ, 60mg/kg). In STZ rats, atorvastatin feeding (20mg/kg/d, 7 weeks), normalized vascular dysfunction as analyzed by isometric tens…
Preparation and Characterization of Inulin Coated Gold Nanoparticles for Selective Delivery of Doxorubicin to Breast Cancer Cells
2016
A novel folate-targeted gold-based nanosystem for achieving selectivity towards folate receptor FR positive cells is proposed, by virtue of the fact that the FR is a molecularly targeted entity overexpressed in a wide spectrum of solid tumors. A new inulin-folate derivative INU-FA has been synthesized to act as coating agent for 40 nm gold nanoparticles. The obtained polymer-coated gold nanoparticles [email protected] were characterized in terms of hydrodynamic radius, shape, zeta potential, and aqueous stability and were loaded with doxorubicin [email protected]/Doxo. Its release capability was tested in different release media. The selectivity of [email protected]/Doxo system towards FRs-…
Impact of hypoxia on chemoresistance of mesothelioma mediated by the proton-coupled folate transporter, and preclinical activity of new anti-LDH-A co…
2020
Abstract Background Expression of proton-coupled folate transporter (PCFT) is associated with survival of mesothelioma patients treated with pemetrexed, and is reduced by hypoxia, prompting studies to elucidate their correlation. Methods Modulation of glycolytic gene expression was evaluated by PCR arrays in tumour cells and primary cultures growing under hypoxia, in spheroids and after PCFT silencing. Inhibitors of lactate dehydrogenase (LDH-A) were tested in vitro and in vivo. LDH-A expression was determined in tissue microarrays of radically resected malignant pleural mesothelioma (MPM, N = 33) and diffuse peritoneal mesothelioma (DMPM, N = 56) patients. Results Overexpression of hypoxia…