In patients receiving hemodialysis, it has long been recognized that much more bicarbonate is delivered during treatment than ultimately appears in the blood. To gain insight into this mystery, we developed a model that allows a quantitative analysis of the patient's response to rapid alkalinization during hemodialysis. Our model is unique in that it is based on the distribution of bicarbonate in the extracellular fluid and assesses its removal from this compartment by mobilization of protons (H ) from buffers and other sources. The model was used to analyze the pattern of rise in blood bicarbonate concentration ([HCO ]), calculated from measurements of pH and PCO , in patients receiving standard bicarbonate hemodialysis. Model analysis demonstrated two striking findings: (1) 35% of the bicarbonate added during hemodialysis was due to influx and metabolism of acetate, despite its low concentration in the bath solution, because of the rapidly collapsing gradient for bicarbonate influx. (2) Almost 90% of the bicarbonate delivered to the patients was neutralized by H generation. Virtually all the new H came from intracellular sources and included both buffering and organic acid production. The small amount of added bicarbonate retained in the extracellular fluid increased blood [HCO ], on average, by 6 mEq/L in our patients. Almost all this rise occurred during the first 2 hours. Thereafter, blood [HCO ] changed minimally and always remained less than bath [HCO ]. This lack of equilibrium was due to the continued production of organic acid. Release of H from buffers is a reversible physiological response, restoring body alkali stores. By contrast, organic acid production is an irreversible process during hemodialysis and is metabolically inefficient and potentially catabolic. Our analysis underscores the need to develop new approaches for alkali repletion during hemodialysis that minimize organic acid production.
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http://dx.doi.org/10.1111/sdi.12714 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Memorial University of Newfoundland, Chemistry, Department of Chemistry, 230 Elizabeth avenue, A1B 3X7, St. John's, CANADA.
Developing the mechanism for MOF formation is crucial for the rapid development of new materials. This work demonstrates that Deuterium-NMR spectroscopy is the optimal inter-laboratory methodology for understanding the in-situ kinetics of metal-organic framework (MOF) formation. This method is facile, affordable, and allows for the isolation and monitoring of individual reagents by using one deuterated component while the remaining components are protonated.
View Article and Find Full Text PDFMethods Mol Biol
January 2025
Biomic Auth, Bioanalysis and Omics Laboratory, Center for Interdisciplinary Research and Innovation, Aristotle University, Thessaloniki, Greece.
Metabolomics aims at identification and quantitation of key end point metabolites, basically polar, in order to study changes in biochemical activities in response to pathophysiological stimuli or genetic modifications. Targeted profiling assays enjoying a growing popularity over the last years with LC-MS/MS as a powerful tool for development of such (semi-)quantitative methods for a large number of metabolites. Here we describe a method for absolute quantitation of ca.
View Article and Find Full Text PDFMikrochim Acta
January 2025
Key Laboratory of Organic Integrated Circuit, Ministry of Education & Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University, Tianjin, 300072, China.
A Cr-doped VO nanobelt (Cr/VO) with remarkable peroxidase-like activity was synthesized and coupled with uricase to catalyze the cascade reaction for detection of uric acid. Notably, the affinity of Cr/VO for 3,3',5,5'-tetramethylbenzidine dihydrochloride hydrate (TMB) and hydrogen peroxide (HO) is tenfold and 20-fold higher, respectively, than that of horseradish peroxidase (HRP). The Cr/VO exhibits highly reactive and stable peroxidase activity at temperatures of 20-60 ℃.
View Article and Find Full Text PDFACS Nano
January 2025
Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, Hunan 410013, China.
Atherosclerosis (AS) is a prevalent inflammatory vascular disease characterized by plaque formation, primarily composed of foam cells laden with lipids. Despite lipid-lowering therapies, effective plaque clearance remains challenging due to the overexpression of the CD47 molecule on apoptotic foam cells, inhibiting macrophage-mediated cellular efferocytosis and plaque resolution. Moreover, AS lesions are often associated with severe inflammation and oxidative stress, exacerbating disease progression.
View Article and Find Full Text PDFActa Diabetol
January 2025
Department of Obstetrics, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Objective: The objective is to investigate the differences in urinary organic acid (OA) profiles and metabolism between healthy control (HC) pregnant women and those with gestational diabetes mellitus (GDM) during the second trimester and third trimester of pregnancy.
Methods: A total of 66 HC pregnant women and 32 pregnant women with GDM were assessed for 107 hydrophilic metabolites in urine samples collected during the second and third trimester of pregnancy using tandem mass spectrometry. The urine OA profiles for each group were obtained, and metabolomic analysis and discussion were conducted.
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