Publications by authors named "Maria Valdivia-Garcia"

Background: We conducted a single-arm interventional study, to explore mucosal changes associated with clinical remission under oral vancomycin (OV) treatment, in primary sclerosing cholangitis associated inflammatory bowel disease (PSC-IBD); NCT05376228.

Method: Fifteen patients with PSC and active colitis (median faecal calprotectin 459µg/g; median total Mayo score 5) were treated with OV (125mg QID) for 4 weeks and followed-up for a further 4 weeks of treatment withdrawal (8 weeks, end-of-study). Colonic biopsies were obtained at baseline and week 4.

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Trimethylamine (TMA) and trimethylamine-N-oxide (TMAO) play a crucial role in many biochemical processes within diverse organisms including animals, plants, fungi and bacteria. Studies have linked these metabolites with cardiovascular and kidney diseases; however, emerging evidence demonstrates their protective properties. Owing to these controversies and co-existence of these metabolites in biological samples, it is crucial to accurately quantify these metabolites to associate their concentrations with various physiological and pathophysiological conditions to elucidate their potential roles.

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  • The human ileum has a lot of L-cells that produce hormones like GLP-1 and PYY, which help suppress appetite when we eat.
  • A study explored how different diets (high-fiber vs. low-fiber) affect the release of these hormones and their connection to food structure and ileal metabolites.
  • Results showed that high-fiber diets significantly boosted PYY release compared to low-fiber, and the study found changes in the ileum's molecular environment after eating, linking it to appetite regulation.
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  • High-fibre diets improve health by promoting the production of short-chain fatty acids (SCFAs) through gut microbiota fermentation, but the mechanisms behind certain high-fibre foods like mycoprotein (Quorn) remain unclear.
  • An investigation using fresh stool samples found that pre-digested mycoprotein didn't significantly alter gut microbiota diversity, pH, or SCFA levels compared to other foods like soy and chicken.
  • Chicken supplementation resulted in a notable increase in total SCFAs, particularly propionate, demonstrating that mycoprotein was not effectively fermented by the gut microbiota in this experiment.
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  • Rectal swabs are commonly used in clinical practice to analyze gut microbiota, but their reliability compared to stool samples has been unclear.
  • A study comparing paired stool and rectal swab samples from healthy individuals found no significant differences in microbial diversity and composition.
  • Additionally, there was a strong correlation in inferred gut functionality and metabolite levels between the two sample types, suggesting rectal swabs can effectively replace stool samples for microbiota analysis.
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Short-chain carboxylic acids (SCCAs) produced by gut microbial fermentation may reflect gastrointestinal health. Their concentrations in serum and urine are indicative of specific metabolic pathway activity; therefore, accurate quantitation of SCCAs in different biofluids is desirable. However, it is often challenging to quantitate SCCAs since matrix effects, induced by the presence of a vast variety of other compounds other than SCCAs in complex biofluids, can suppress or enhance signals.

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Summary: We present LipidFinder 2.0, incorporating four new modules that apply artefact filters, remove lipid and contaminant stacks, in-source fragments and salt clusters, and a new isotope deletion method which is significantly more sensitive than available open-access alternatives. We also incorporate a novel false discovery rate method, utilizing a target-decoy strategy, which allows users to assess data quality.

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Quantitative predictions of impacts on public water supplies are essential for planning climate change adaptations. Monitoring data from five full-scale Scottish drinking water treatment plants (DWTPs) showed that significant correlations exist between conditionally carcinogenic trihalomethanes (THMs) levels, water temperature (r = 0.812, p = 0.

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Purpose: Adherence to disease-modifying treatments is essential in order to maximize the beneficial effects of treatment for multiple sclerosis (MS). There are numerous treatments that have been approved. Treatment selection is essential in patient adherence.

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Trihalomethanes (THMs) are conditionally carcinogenic compounds formed during chlorine disinfection in water treatment processes around the world. THMs occur especially when source waters are subject to marine influences, high and-or regular precipitation, and elevated levels of organic matter. THMs formation is then rooted in geographic, operational and climatic factors, the relative importance of which can only be derived from large datasets and may change in the future.

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S-adenosylmethionine (SAM) is synthesized from methionine, which is abundant in animal-derived protein, in an energy-consuming reaction. SAM and S-adenosylhomocysteine (SAH) correlate with body mass index (BMI). Plasma total concentration of the SAM-associated product cysteine (tCys) correlates with fat mass in humans and cysteine promotes adiposity in animals.

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Objectives: Methionine-restricted (MR) rats, which are lean and insulin sensitive, have low serum total cysteine (tCys) and taurine and decreased hepatic expression and activity indices of stearoyl-coenzyme A desaturase-1 (SCD1). These effects are partly or completely reversed by cysteine supplementation. We investigated whether reversal of MR phenotypes can be achieved by other sulfur compounds, namely taurine or N-acetylcysteine (NAC).

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Context: Plasma total cysteine (tCys) independently relates to fat mass in adults. Dietary cyst(e)ine promotes adiposity and decreases glucose tolerance in some rodent models, but alleviates insulin resistance in others.

Objective: To investigate whether the association of tCys with body fat extends to children at particular risk of obesity, and whether tCys is associated with insulin resistance and obesity-associated inflammation.

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Plasma total cysteine (tCys) concentrations are associated with BMI. To study the relationship between tCys and BMI, we monitored the changes in serum concentrations of tCys and metabolically related compounds in sixty obese patients (BMI 50-60 kg/m(2)) from before to 1 year after either gastric bypass surgery (mean 30 % weight loss) or duodenal switch surgery (mean 41 % weight loss). A total of fifty-eight healthy persons (BMI 17-31 kg/m(2)) served as controls.

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Plasma total cysteine (tCys) is strongly and independently associated with obesity in large human cohorts, but whether the association is causal is unknown. Dietary cyst(e)ine increases weight gain in some rodent models. We investigated the body composition, metabolic rate and metabolic phenotype of mature C3H/HeH mice assigned to low-cystine (LC) or high-cystine (HC) diets for 12 weeks.

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Stearoyl-CoA desaturase-1 (SCD1) is a key enzyme in fatty acid and energy metabolism, but little is known about its nutritional regulation. Dietary methionine restriction in rats decreases hepatic Scd1 mRNA and protein, increases energy expenditure, and decreases fat-pad mass/body-weight% (FM/BW%). In humans, plasma concentrations of the methionine product, cysteine, are associated with obesity.

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Objective: Dietary methionine restriction in Fischer-344 rats favorably influences visceral fat mass, insulin sensitivity, metabolic parameters, and longevity. However, little is known about the effects of methionine restriction on serum methionine and its downstream sulfur amino acids. We investigated the serum sulfur amino acid profile of male Fischer-344 rats fed a methionine-restricted diet for 3 mo.

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