Search results for "aldehyde dehydrogenase"

Two-carbon metabolites, polyphenols and vitamins influence yeast chronological life span in winemaking conditions

2012

Abstract Background Viability in a non dividing state is referred to as chronological life span (CLS). Most grape juice fermentation happens when Saccharomyces cerevisiae yeast cells have stopped dividing; therefore, CLS is an important factor toward winemaking success. Results We have studied both the physical and chemical determinants influencing yeast CLS. Low pH and heat shorten the maximum wine yeast life span, while hyperosmotic shock extends it. Ethanol plays an important negative role in aging under winemaking conditions, but additional metabolites produced by fermentative metabolism, such as acetaldehyde and acetate, have also a strong impact on longevity. Grape polyphenols quercet…

Tumorigenic and metastatic activity of human thyroid cancer stem cells

2010

Abstract Thyroid carcinoma is the most common endocrine malignancy and the first cause of death among endocrine cancers. We show that the tumorigenic capacity in thyroid cancer is confined in a small subpopulation of stem-like cells with high aldehyde dehydrogenase (ALDHhigh) activity and unlimited replication potential. ALDHhigh cells can be expanded indefinitely in vitro as tumor spheres, which retain the tumorigenic potential upon delivery in immunocompromised mice. Orthotopic injection of minute numbers of thyroid cancer stem cells recapitulates the behavior of the parental tumor, including the aggressive metastatic features of undifferentiated thyroid carcinomas, which are sustained by…

Overexpression of ALDH1 and EMT marker profile are linked with unfavorable outcome in head and neck cancer

2020

Background The aim of this research was to assess the expression of aldehyde dehydrogenase 1 (ALDH1) and epithelial-mesenchymal transition (EMT) markers in head and neck squamous cell carcinoma (HNSCC), and to correlate them with the clinical and histopathological parameters of a patient cohort with follow-up over an 8-year period. Material and Methods For this, seventeen HNSCC and non-neoplastic adjacent epithelium (AE) samples were subjected to laser microdissection and real-time PCR to evaluate the mRNA expression of ALDH1, E-cadherin (E-CAD), N-cadherin (N-CAD), and vimentin (VIM). Also, immunohistochemistry was performed for ALDH1, E-CAD, N-CAD, and VIM in the tumor center (TC), invasi…

Number of nitrate groups determines reactivity and potency of organic nitrates: a proof of concept study in ALDH-2−/− mice

2007

Background and purpose: Mitochondrial aldehyde dehydrogenase (ALDH-2) has been shown to provide a pathway for bioactivation of organic nitrates and to be prone to desensitization in response to highly potent, but not to less potent, nitrates. We therefore sought to support the hypothesis that bioactivation by ALDH-2 critically depends on the number of nitrate groups within the nitrovasodilator. Experimental approach: Nitrates with one (PEMN), two (PEDN; GDN), three (PETriN; glyceryl trinitrate, GTN) and four (pentaerithrityl tetranitrate, PETN) nitrate groups were investigated. Vasodilatory potency was measured in isometric tension studies using isolated aortic segments of wild type (WT) an…

the role of mitochondrial aldehyde dehydrognase (ALDH-2) for bioactivation of organic nitrates: “Proof of concept” through investigations in ALDH-2 k…

2006

Explaining the phenomenon of nitrate tolerance.

2005

During the last century, nitroglycerin has been the most commonly used antiischemic and antianginal agent. Unfortunately, after continuous application, its therapeutic efficacy rapidly vanishes. Neurohormonal activation of vasoconstrictor signals and intravascular volume expansion constitute early counter-regulatory responses (pseudotolerance), whereas long-term treatment induces intrinsic vascular changes, eg, a loss of nitrovasodilator-responsiveness (vascular tolerance). This is caused by increased vascular superoxide production and a supersensitivity to vasoconstrictors secondary to a tonic activation of protein kinase C. NADPH oxidase(s) and uncoupled endothelial nitric oxide synthase …

Understanding the release and metabolism of aroma compounds using micro-volume saliva samples by ex vivo approaches

2018

International audience; This study investigated the behaviour of key aroma compounds in the presence of human saliva (200 mu L) from different individuals (n = 3) submitted or not to centrifugation (whole vs clarified saliva). HS-GC results showed that human saliva strongly decreased the release of carbonyl compounds (aldehydes and ketones). This effect was dependent on i) the structure of the aroma compounds and ii) the saliva composition. Whole saliva exerted a higher effect than clarified saliva on aroma compounds. Moreover, this effect was individual-dependent and related to the total protein content and the total antioxidant capacity of saliva. HS-SPME and LLE-GC/MS analyses revealed t…

THERAPEUTIC EFFICACY OF MAGNESIUM VALPROATE IN SUCCINIC SEMIALDEHYDE DEHYDROGENASE DEFICIENCY

2012

Succinic semialdehyde dehydrogenase deficiency (SSADHD or gammahydroxybutyric aciduria), a disorder of γ-aminobutyric acid (GABA) metabolism, manifests as a slowly progressive or static encephalopathy. The latter encompasses prominent cognitive dysfunction, neuropsychiatric morbidity and epilepsy.We report safe and effective treatment with MgVPA in an adolescent female with SSADHD and seizures refractory to a broad spectrum of antiepileptics. MgVPA therapy (20 mg/Kg/day) was introduced at 7 years based upon behavioural difficulties and EEG alterations without adverse effects. Therapy was halted at age 13 years, and reintroduced at 14 years, due to new onset complex partial seizures. EEG dem…

Regulation of Human Mitochondrial Aldehyde Dehydrogenase (ALDH-2) Activity by Electrophiles in Vitro

2011

Recently, mitochondrial aldehyde dehydrogenase (ALDH-2) was reported to reduce ischemic damage in an experimental myocardial infarction model. ALDH-2 activity is redox-sensitive. Therefore, we here compared effects of various electrophiles (organic nitrates, reactive fatty acid metabolites, or oxidants) on the activity of ALDH-2 with special emphasis on organic nitrate-induced inactivation of the enzyme, the biochemical correlate of nitrate tolerance. Recombinant human ALDH-2 was overexpressed in Escherichia coli; activity was determined with an HPLC-based assay, and reactive oxygen and nitrogen species formation was determined by chemiluminescence, fluorescence, protein tyrosine nitration,…

Role of Reduced Lipoic Acid in the Redox Regulation of Mitochondrial Aldehyde Dehydrogenase (ALDH-2) Activity

2007

Chronic therapy with nitroglycerin results in a rapid development of nitrate tolerance, which is associated with an increased production of reactive oxygen species. We have recently shown that mitochondria are an important source of nitroglycerin-induced oxidants and that the nitroglycerin-bioactivating mitochondrial aldehyde dehydrogenase is oxidatively inactivated in the setting of tolerance. Here we investigated the effect of various oxidants on aldehyde dehydrogenase activity and its restoration by dihydrolipoic acid. In vivo tolerance in Wistar rats was induced by infusion of nitroglycerin (6.6 microg/kg/min, 4 days). Vascular reactivity was measured by isometric tension studies of iso…