Search results for "Metabolite"
showing 10 items of 551 documents
6-thioguanosine diphosphate and triphosphate levels in red blood cells and response to azathioprine therapy in Crohn's disease.
2005
Background & Aims: Azathioprine is the gold standard for immunosuppressive therapy in Crohn's disease (CD) and its molecular mechanism of action is caused by the metabolite 6-thioguanosine triphosphate (TGTP). In this study we assessed the impact of TGTP levels for monitoring of azathioprine therapy. Methods: A novel, highly sensitive assay was established to measure levels of TGTP and its precursors 6-thioguanosine monophosphates and 6-thioguanosine diphosphates (TGDP) in red blood cells from 50 CD patients. The results were correlated with clinical outcome. Results: TGTP levels could be quantified in 47 patients and a subgroup of these patients showed significantly high levels of TGDP. 6-…
Analysis of serum and endometrial progesterone in determining endometrial receptivity.
2021
Abstract STUDY QUESTION Is there a relationship between serum and endometrial progesterone (P4) levels, including P4 and metabolites (oestrone, oestradiol and 17α-hydroxyprogesterone), and endometrial receptivity? SUMMARY ANSWER Serum P4 levels were not correlated with endometrial P4, nor associated with endometrial receptivity as determined by the ERA® test; however, endometrial P4 and 17α-hydroxyprogesterone levels were positively correlated and related to endometrial receptivity by ERA. WHAT IS KNOWN ALREADY Acquisition of endometrial receptivity is governed by P4, which induces secretory transformation. A close relationship between serum P4 and pregnancy outcome is reported for hormone …
Unruptured tubal pregnancy: local low-dose therapy with methotrexate under transvaginal ultrasonographic guidance.
1996
Thirty patients with unruptured ectopic pregnancy (4-10 weeks' gestation) were treated locally with methotrexate (MTX) under sonographic guidance. The transvaginal puncture was performed under analgesic sedation using an automatic puncturing device. Local MTX therapy was successful in 25 patients (83.3%). Eighteen of these patients had received a single MTX instillation with a total dose of 10 mg, 7 patients had received a second instillation with 10 mg because of plateauing hCG levels after the first instillation. In 5 patients MTX therapy was unsuccessful. Surgical intervention was necessary within 4 h to 15 days after MTX treatment, due to severe tubal bleeding (n = 1) or the development…
Dominant contribution of P450 3A4 to the hepatic carcinogenic activation of aflatoxin B1.
2006
The hepatic carcinogen aflatoxin B1 (AFB1) is metabolized in the liver by at least four different P450s, all of which exhibit large interindividual differences in the expression levels. These differences could affect the individual risk of hepatocellular carcinoma (HCC). We investigated the metabolism of AFB1 in a panel of 13 human liver microsomal preparations using a hepatic abundance model, which takes into account the specific kinetic parameters and the expression levels of these P450s. We found a 12-fold variability in the production rate of the carcinogenic metabolite AFB1-8,9-epoxide (AFBO) and a 22-fold variability in the production of the detoxification product AFQ1. The ratio betw…
Systemic administration of D-penicillamine prevents the locomotor activation after intra-VTA ethanol administration in rats.
2010
Although recently published studies seem to confirm the important role displayed by acetaldehyde (ACH), the main metabolite of ethanol, in the behavioral effects of ethanol, the origin of ACH is still a matter of debate. While some authors confer more importance to the central (brain metabolism) origin of ACH, others indicate that the hepatic origin could be more relevant. In this study we have addressed this topic using an experimental approach that combines local microinjections of ethanol into the ventral tegmental area (VTA) (which guarantees the brain origin of the ACH) to induce motor activation in rats together with systemic administration (i.p.) of several doses (0, 12.5, 25 and 50 …
Propagation of Calendula maritima Guss. (Asteraceae) through Biotechnological Techniques for Possible Usage in Phytotherapy
2022
The genus Calendula (Asteraceae) includes several species that are renowned for their therapeutic properties and/or use as ingredients in the preparation of cosmetics. The rare and critically endangered sea marigold, Calendula maritima Guss., an endemic species from Western Sicily, has also been recognized as a potential “farm plant species” for several important compounds used in cosmetics. However, the few remnant populations of this species are currently threatened with extinction because of several factors, such as hybridization with the congeneric species Calendula suffruticosa subsp. fulgida (Raf.) Guadagno and anthropogenic disturbance of its habitat. Therefore, in order to preserve …
Pitfalls to be considered on the metabolomic analysis of biological samples by HR-MAS
2014
HR-MAS (High-Resolution Magic AngleSpinning) is considered a powerfultechnique for metabolomic studies ofbiological samples that provides “intact”tissue spectra (Cheng et al., 1998; Waterset al., 2000; Sitter et al., 2002; Martinez-Bisbal et al., 2004; Payne et al., 2006;Coen et al., 2007; Bathen et al., 2010).The performance of HR-MAS, fol-lowed by quantitative histopathology hasdemonstrated that, despite some changes,HR-MAS can preserve approximately thetissue histopathologic features producingwell-resolved spectra of cellular metabo-lites (Cheng et al., 2000). Nevertheless,therearesomeaspectsarousedintheliter-ature about the possible biochemical andstructural changes that can occur durin…
Aroma release in the oral cavity after wine intake is influenced by wine matrix composition
2018
The aim of this study has been to investigate if wine matrix composition might influence the interaction between odorants and oral mucosa in the oral cavity during a “wine intake-like” situation. Aroma released after exposing the oral cavity of three individuals to different wines (n = 12) previously spiked with six target aromas was followed by an -in vivo intra-oral SPME approach. Results showed a significant effect of wine matrix composition on the intra-oral aroma release of certain odorants. Among the wine matrix parameters, phenolic compounds showed the largest impact. This effect was dependent on their chemical structure. Some phenolic acids (e.g. hippuric, caffeic) were associated t…
Stereoselective anti aldol reactions of erythrulose derivatives. Functionalized chiral d3 and d4 synthons.
2004
An improved procedure for the synthesis of anti aldols from protected erythrulose derivatives is reported. The preparation of functionalized d3 and d4 synthons with various stereochemical arrays by means of this methodology is described and subsequently applied to a stereoselective formal synthesis of the natural metabolite goniothalesdiol.
Identification of conjugation and cleavage products in the thiolytic metabolism of the anticancer drug 4'-(9-acridinylamino)methanesulfon-m-anisidide.
1981
Conjugation and cleavage products in the thiolytic metabolism of the anticancer drug 4′ -(9-acridinyl amino)methanesulfon-m-anisidide were identified primarily by high-pressure liquid chromatography in combination with field desorption mass spectrometry. The spontaneous metabolic pathway of the drug, as related to its susceptibility to nucleophilic attack by endogenous thiols at the 9-carbon atom of the acridine moiety, has been studied. Among the metabolite fraction of 4′-(9-acridinylamino)methanesulfon-m-anisidide excreted in rat bile after administration of a therapeutic dose, a conjugate was identified as the 9-acridinyl thioether of glutathione. This conjugation product and the corresp…