Effect of Stool Sampling on a Routine Clinical Method for the Quantification of Six Short Chain Fatty Acids in Stool Using Gas Chromatography-Mass Spectrometry.

Short chain fatty acids (SCFAs) are primarily produced in the caecum and proximal colon via the bacterial fermentation of undigested carbohydrates that have avoided digestion in the small intestine. Increasing evidence supports the critical role that SCFAs play in health and homeostasis. Microbial SCFAs, namely butyric acid, serve as a principal energy source for colonocytes, and their production is essential for gut integrity. A direct link between SCFAs and some human pathological conditions, such as inflammatory bowel disease, irritable bowel syndrome, diarrhea, and cancer, has been proposed. The direct measurement of SCFAs in feces provides a non-invasive approach to demonstrating connections between SCFAs, microbiota, and metabolic diseases to estimate their potential applicability as meaningful biomarkers of intestinal health. This study aimed to adapt a robust analytical method (liquid-liquid extraction, followed by isobutyl chloroformate derivatization and GC-MS analysis), with comparable performances to methods from the literature, and to use this tool to tackle the question of pre-analytical conditions, namely stool processing. We focused on the methodology of managing stool samples before the analysis (fresh stool or dilution in either ethanol/methanol, lyophilized stool, or RNAlater®), as this is a significant issue to consider for standardizing results between clinical laboratories. The objective was to standardize methods for future applications as diagnostic tools. In this paper, we propose a validated GC-MS method for SCFA quantification in stool samples, including pre- and post-analytical comparison studies that could be easily used for clinical laboratory purposes. Our results show that using lyophilization as a stool-processing method would be the best method to achieve this goal.

High performance liquid chromatography-tandem mass spectrometry quantification of tryptophan metabolites in human serum and stool - Application to clinical cohorts in Inflammatory Bowel Diseases.

Tryptophan, an essential amino acid, and its metabolites are involved in many physiological processes including neuronal functions, immune system, and gut homeostasis. Alterations to tryptophan metabolism are associated with various pathologies such as neurologic, psychiatric disorders, inflammatory bowel diseases (IBD), metabolic disorders, and cancer. It is consequently critical to develop a reliable, quantitative method for the analysis of tryptophan and its downstream metabolites from the kynurenine, serotonin, and indoles pathways. An LC-MS/MS method was designed for the analysis of tryptophan and 20 of its metabolites, without derivatization and performed in a single run. This method was validated for both serum and stool. The comparisons between serum and plasma, collected with several differing anticoagulants, showed significant differences only for serotonin. References values were established in sera and stools from healthy donors. For stool samples, as a proof of concept, the developed method was applied to a healthy control group and an IBD patient group. Results showed significant differences in the concentrations of tryptophan, xanthurenic acid, kynurenic acid, indole-3-lactic acid, and picolinic acid. This method allowed an extensive analysis of the three tryptophan metabolic pathways in two compartments. Beyond the application to IBD patients, the clinical use of this method is wide-ranging and may be applied to other pathological conditions involving tryptophan metabolism, such as neurological, psychiatric, or auto-inflammatory pathologies.

Diaphragmatic Hernia with Gastric Volvulus and Complete Gastric Outlet Obstruction.

A combination of Cytoreductive surgery (CRS) along with hyperthermic intraperitoneal chemotherapy (HIPEC) considers a crucial approach in treating designated patients with alimentary and gynecological malignancies with the involvement of the peritoneal cavity. The foremost frequent surgical complications are leakage, digestive perforations, fistulas, intestinal obstruction, abscess, and peripancreatitis. This report presents a case of a patient with a late acquired herniation of guts through the diaphragm after CRS and HIPEC that were already done 6 months back. A 26 -yearold male previously treated with CRS and HIPEC for testicular mesothelioma with peritoneal involvement, was admitted to our unit with the diagnosis of gastric outlet obstruction. His CT scan illustrated a left diaphragmatic hernia involving the stomach and splenocolic flexure. Each denudation of the diaphragmatic serosa throughout CRS which typically occurs during the surgical operation in a combination of the HIPEC heat can explain such complication. The herniation is extremely uncommonly diagnosed after CRS and HIPEC. Surgical techniques for hernia repair can be done by direct suturing of the defect or closure with artificial or biological tissue, each technique is a potential surgical technique for repair with reliable long-run results.