Objectives: No individual homocysteine (Hcy) metabolite has been studied as a risk marker for coronary artery disease (CAD). Our objective was to examine Hcy‐thiolactone, a chemically reactive metabolite generated by methionyl‐tRNA synthetase and cleared by the kidney, as a risk predictor of incident acute myocardial infarction (AMI) in the Western Norway B‐Vitamin Intervention Trial.Design: Single centre, prospective double‐blind clinical intervention study, randomized in a 2 × 2 factorial design.Subjects and methods: Patients with suspected CAD (n = 2049, 69.8% men; 61.2‐year‐old) were randomized to groups receiving daily (i) folic acid (0.8 mg)/vitamin B₁₂ (0.4 mg)/vitamin B₆ (40 mg); (ii) folic acid/vitamin B₁₂; (iii) vitamin B₆ or (iv) placebo. Urinary Hcy‐thiolactone was quantified at baseline, 12 and 38 months.Results: Baseline urinary Hcy‐thiolactone/creatinine was significantly associated with plasma tHcy, ApoA1, glomerular filtration rate, potassium and pyridoxal 5′‐phosphate (positively) and with age, hypertension, smoking, urinary creatinine, plasma bilirubin and kynurenine (negatively). During median 4.7‐years, 183 patients (8.9%) suffered an AMI. In Cox regression analysis, Hcy‐thiolactone/creatinine was associated with AMI risk (hazard ratio = 1.58, 95% confidence interval = 1.10–2.26, P = 0.012 for trend; adjusted for age, gender, tHcy). This association was confined to patients with pyridoxic acid below median (adjusted HR = 2.72, 95% CI = 1.47–5.03, P = 0.0001; P_interaction = 0.020). B‐vitamin/folate treatments did not affect Hcy‐thiolactone/creatinine and its AMI risk association.Conclusions: Hcy‐thiolactone/creatinine ratio is a novel AMI risk predictor in patients with suspected CAD, independent of traditional risk factors and tHcy, but modified by vitamin B₆ catabolism. These findings lend a support to the hypothesis that Hcy‐thiolactone is mechanistically involved in cardiovascular disease.

The natural microbiota of the urinary tract includes Lactobacillus spp., which secrete molecules with antimicrobial properties and have antagonistic activity against many pathogens. This paper focuses on the antibacterial effect of Lactobacillus strains isolated from urine against clinical strains of Proteus mirabilis isolated from kidney stones and from urine with coexisting urolithiasis. The study involved analyzing the main antimicrobial molecules secreted by Lactobacillus. In order to indicate which agent had the strongest antimicrobial effect, the supernatants were made alkaline and treated with catalase and high temperature. Both treated and untreated supernatants were analyzed for their activity. Exposing uropathogens to all untreated cell-free supernatants of Lactobacillus significantly reduced their growth, and it was established that these properties were related to organic acid secretion by these strains. Using LC–MS/MS and spectrophotometric techniques, lactic, citric, and succinic acids were determined qualitatively and quantitatively. The influence of these acids on the P. mirabilis growth and biofilm formation and their influence on membrane permeability were also investigated. The results indicate that organic acids secreted by Lactobacillus strains have a high antibacterial potential and could be used as novel agents in the treatment of urinary tract infections caused by P. mirabilis.

Gas chromatography–mass spectrometry technique (GC-MS) is mainly recognized as a tool of first choice when volatile compounds are determined. Here, we provide the credible evidence that its application in analysis can be extended to non-volatile sulfur-containing compounds, to which methionine (Met), homocysteine (Hcy), homocysteine thiolactone (HTL), and cysteine (Cys) belong. To prove this point, the first method, based on GC-MS, for the identification and quantification of Met-related compounds in human saliva, has been elaborated. The assay involves simultaneous disulfides reduction with tris(2-carboxyethyl)phosphine (TCEP) and acetonitrile (MeCN) deproteinization, followed by preconcentration by drying under vacuum and treatment of the residue with a derivatizing mixture containing anhydrous pyridine, N-trimethylsilyl-N-methyl trifluoroacetamide (MSTFA), and trimethylchlorosilane (TMCS). The validity of the method was demonstrated based upon US FDA recommendations. The assay linearity was observed over the range of 0.5–20 µmol L⁻¹ for Met, Hcy, Cys, and 1–20 µmol L⁻¹ for HTL in saliva. The limit of quantification (LOQ) equals 0.1 µmol L⁻¹ for Met, Hcy, Cys, while its value for HTL was 0.05 µmol L⁻¹. The method was successfully applied to saliva samples donated by apparently healthy volunteers (n = 10).

Context: The main source of bufadienolides is toad venom; however, plants such as members of Kalanchoe Adans. (Crassulaceae) genus may also synthesize these bioactive substances. Objective: This is the first study on antioxidant effects and cytotoxicity of bufadienolide-rich fraction isolated from Kalanchoe daigremontiana Raym.-Hamet & H. Perrier. Materials and methods: The methanolic fraction was extracted from the plant roots and contained 0.48 mg bufadienolides/mg of dry mass (11α,19-dihydroksytelocinobufagin, bersaldegenin-1-acetate, bersaldegenin-1,3,5-orthoacetate, 19-(acetyloxy)-3β,5β,11α,14-tetrahydroxyl-12-oxo-bufa-20,22-dienolide and 19-(acetyloxy)-1β,3β,5β,14-tetrahydroxyl-bufa-20,22-dienolide, mainly). The cytotoxicity of K. daigremontiana fraction was evaluated in an in vitro experimental model of blood platelets. The viability of blood platelets was determined on the basis of a release of lactate dehydrogenase. Results: The fraction scavenged DPPH^• radicals, with EC₅₀ of 21.80 μg/mL. Studies on an experimental model of blood plasma under peroxynitrite-induced oxidative stress revealed that the plant preparation had moderate antioxidant properties. Levels of 3-nitrotyrosine and thiol groups indicated that the protective effect of K. daigremontiana was significant mainly for its concentration of 50 μg/mL. No effect was found in prevention of oxidation of low-molecular plasma thiols (glutathione, cysteine and cysteinylglycine). Simultaneously, measurements of lipid hydroperoxides and thiobarbituric acid-reactive substances (TBARS) indicated that the examined fraction might be effective antioxidant at broader concentration range, that is 1–5 and 25–50 μg/mL for hydroperoxides and TBARS generation, respectively. No cytotoxicity was observed at the concentration range of 1–50 μg/mL. Conclusions: Based on the obtained results, we suggest that antioxidant activity may additionally contribute to beneficial properties of K. daigremontiana-derived extracts.

In this work, the use of square-wave adsorptive stripping voltammetry (SWAdSV) in combination with boron-doped diamond electrode modified with multiwalled carbon nanotubes (MWCNTs-BDDE) and β-cyclodextrin (β-CD, β-CD-MWCNTs-BDDE) for the determination of the fungicide carbendazim (Cbz) is described for the first time. Cbz oxidation response was observed in the Britton-Robinson buffer supporting electrolyte in a pH range from 2.3 to 6.0 in potential range from + 1.0 to + 1.3 V vs SCE. The SWAdSV peak current of Cbz oxidation response on β-CD-MWCNTs-BDDE with peak maxima close to + 1.2 V vs SCE at pH 4.0 was linear over the wide linear dynamic range of 6.72 × 10⁻⁷–1.12 × 10⁻⁵ mol L⁻¹ with a detection limit (LOD) of 1.96 × 10⁻⁷ mol L⁻¹. The obtained results demonstrated the viability of the proposed methodology for determination of Cbz in river water samples containing low concentrations of Cbz. Moreover, the effect of Cbz on the corrosion properties of an AISI type 316 L stainless steel used to fabricate farming equipment and tools was tested by means of the potentiodynamic method. The characterization and evaluation of the corrosion inhibition effect raised from the use of Cbz was performed using optical microscope.