It has been demonstrated that freezing-induced acidity changes have an impact on the structural integrity, degree of aggregation, and chemical stability of frozen food and pharmaceutical products. The stability of the compounds in solutions is maintained by the presence of buffers. However, many buffers are unsuitable for applications involving freezing as this process substantially alters the acidity. In this study, we determine the effect of initial pH, concentration, and cooling rate on the freezing-induced change in acidity of phosphate buffered saline (PBS) in the frozen state via UV-VIS spectroscopy. Furthermore, we examine the impact of individual salts present in PBS and discuss the mechanisms affecting the resulting acidity that we approximate via Hammett acidity function (H2-).

• MeSH
• Phosphates * chemistry   MeSH
• Hydrogen-Ion Concentration MeSH
• Buffers MeSH
• Saline Solution * chemistry   MeSH
• Freezing MeSH
• Publication type
• Journal Article MeSH

OBJECTIVES: To evaluate the base excess response during acute in vivo carbon dioxide changes. DESIGN: Secondary analysis of individual participant data from experimental studies. SETTING: Three experimental studies investigating the effect of acute in vivo respiratory derangements on acid-base variables. SUBJECTS: Eighty-nine (canine and human) carbon dioxide exposures. INTERVENTIONS: Arterial carbon dioxide titration through environmental chambers or mechanical ventilation. MEASUREMENTS AND MAIN RESULTS: For each subject, base excess was calculated using bicarbonate and pH using a fixed buffer power of 16.2. Analyses were performed using linear regression with arterial dioxide (predictor), base excess (outcome), and studies (interaction term). All studies show different baselines and slopes for base excess across carbon dioxide titrations methods. Individual subjects show substantial, and potentially clinically relevant, variations in base excess response across the hypercapnic range. Using a mathematical simulation of 10,000 buffer power coefficients we determined that a coefficient of 12.1 (95% CI, 9.1-15.1) instead of 16.2 facilitates a more conceptually appropriate in vivo base excess equation for general clinical application. CONCLUSIONS: In vivo changes in carbon dioxide leads to changes in base excess that may be clinically relevant for individual patients. A buffer power coefficient of 16.2 may not be appropriate in vivo and needs external validation in a range of clinical settings.

• MeSH
• Acid-Base Equilibrium * physiology   MeSH
• Adult MeSH
• Hypercapnia physiopathology   metabolism   MeSH
• Hydrogen-Ion Concentration MeSH
• Humans MeSH
• Carbon Dioxide * metabolism   MeSH
• Acid-Base Imbalance physiopathology   metabolism   MeSH
• Dogs MeSH
• Respiration, Artificial MeSH
• Animals MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Male MeSH
• Dogs MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

Distance-based detection (DbD) on paper-based microfluidic analytical devices (μPADs) has emerged as a promising, cost-effective, simple, and instrumentation-free assay method. Broadening the applicability of a new way of immobilization of reagent for DbD on μPADs (DμPADs) is presented, employing an ion exchange (IE) interaction of an anionic metallochromic reagent, 2-(5-bromo-2-pyridylazo)-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol (5-Br-PAPS), on the anion-exchange filter paper. The IE DμPADs demonstrate superiority over standard cellulose filter paper in terms of the degree of reagent immobilization, detection sensitivity, and clear detection endpoints due to the strong retention of 5-Br-PAPS. The study investigated various parameters influencing DbD, including 5-Br-PAPS concentrations (0.25-1 mM), buffer types (acetic acid-Tris, MES), buffer concentrations (20-500 mM), and auxiliary complexing agents (acetic, formic, and glycolic acids). Subsequently, the performance of 17 metals (Ag+, Cd2+, Co2+, Cr3+, Cu2+, Fe2+, Hg2+, La2+, Mn2+, Ni2+, Pb2+, Ti2+, Zn2+, Al3+, As3+, Fe3+, and V4+) was evaluated, with color formation observed for 12 metals. Additionally, the paper surface was examined using SEM and SEM-EDX to verify the suitability of certain areas in the detection channel for reagent immobilization and metal binding. This method demonstrates quantitation limits of metals in the low μg mL-1 range, showing great potential for the rapid screening of toxic metals commonly found in herbal supplements and cosmetics regulated by the Food and Drug Administration (FDA). Thus, it holds promise for enhancing safety and regulatory compliance in product quality assessment. Furthermore, this method offers a cost-effective, environmentally sustainable, and user-friendly approach for the rapid visual quantification of heavy metals for in-field analysis, eliminating the need for complex instrumentation.

• Publication type
• Journal Article MeSH

• MeSH
• Biochemistry MeSH
• Metabolic Diseases MeSH
• Pathology MeSH

• Conspectus
• Patologie. Klinická medicína
• Učební osnovy. Vyučovací předměty. Učebnice
• NML Fields
• biochemie
• patologie
• NML Publication type
• učebnice vysokých škol

Alginate lyases have countless potential for application in industries and medicine particularly as an appealing biocatalyst for the production of biofuels and bioactive oligosaccharides. Solid-state fermentation (SSF) allows improved production of enzymes and consumes less energy compared to submerged fermentation. Seaweeds can serve as the most promising biomass for the production of biochemicals. Alginate present in the seaweed can be used by alginate lyase-producing bacteria to support growth and can secrete alginate lyase. In this perspective, the current study was directed on the bioprocessing of brown seaweeds for the production of alginate lyase using marine bacterial isolate. A novel alginate-degrading marine bacterium Enterobacter tabaci RAU2C which was previously isolated in the laboratory was used for the production of alginate lyase using Sargassum swartzii as a low-cost solid substrate. Process parameters such as inoculum incubation period and moisture content were optimized for alginate lyase production. SSF resulted in 33.56 U/mL of alginate lyase under the static condition maintained with 75% moisture after 4 days. Further, the effect of different buffers, pH, and temperature on alginate lyase activity was also analyzed. An increase in alginate lyase activity was observed with an increase in moisture content from 60 to 75%. Maximum enzyme activity was perceived with phosphate buffer at pH 7 and 37 °C. Further, the residual biomass after SSF could be employed as biofertilizer for plant growth promotion based on the preliminary analysis. To our knowledge, this is the first report stating the usage of seaweed biomass as a substrate for the production of alginate lyase using solid-state fermentation.

• MeSH
• Alginates * metabolism   MeSH
• Biomass MeSH
• Enterobacter * metabolism   enzymology   isolation & purification   growth & development   MeSH
• Fermentation * MeSH
• Hydrogen-Ion Concentration MeSH
• Glucuronic Acid metabolism   MeSH
• Seaweed * microbiology   MeSH
• Phaeophyceae microbiology   MeSH
• Polysaccharide-Lyases * metabolism   MeSH
• Sargassum * microbiology   metabolism   MeSH
• Temperature MeSH
• Publication type
• Journal Article MeSH

This double-blind placebo-controlled cross-over study utilized comprehensive monitoring of blood bicarbonate (HCO3 ̄) kinetics and evaluation of gastrointestinal (GI) upset to determine their impact on an ergogenic potential of sodium bicarbonate (SB) co-ingested with carbohydrate (CHO). Nineteen CrossFit athletes performed 6 bouts of 15 s Wingate Anaerobic Test (WAnT) 90 min post-ingestion of 0.4 g·kg-1 body mass (BM) of SB (SB + CHO treatment) or PLA (PLA + CHO treatment) with 15 g CHO. Blood HCO3 ̄ concentration was evaluated at baseline, 30-, 60-, 75- and 90 min post-ingestion, in between WAnT bouts, and 3 and 45 min post-exercise, while GI upset at 120 min after protocol started. Control (no supplementation; CTRL) procedures were also performed. An effective elevation of extra-cellular buffering capacity was observed 60-90 min post-ingestion of SB + CHO. At mean peak blood HCO3 ̄, or at start of exercise an increase > 6 mmol·L-1 in HCO3 ̄ was noted in 84% and 52.6% participants, respectively. SB + CHO did not prevent performance decrements in WAnT bouts. There were no significant relationships between changes in blood HCO3 ̄ and WAnTs' performance. Total GI was significantly higher in SB + CHO compared to CTRL, and stomach problems in SB + CHO compared to CTRL and PLA + CHO. There were inverse associations between peak- (p = 0.031; r = - 0.495), average- (p = 0.002; r = - 0.674) and minimum power (p = 0.008; r = - 0.585) and total GI upset, as well as average power and severe GI distress (p = 0.042; r = - 0.471) at SB + CHO. The implemented dose of SB + CHO was effective in improving buffering capacity, but did not prevent decrements in WAnTs' performance. GI side effects were crucial in affecting the ergogenic potential of SB and thus must be insightfully monitored in future studies.

• MeSH
• Double-Blind Method MeSH
• Gastrointestinal Diseases * chemically induced   MeSH
• Sodium Bicarbonate adverse effects   MeSH
• Bicarbonates MeSH
• Cross-Over Studies MeSH
• Humans MeSH
• Polyesters MeSH
• Athletic Performance * MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Randomized Controlled Trial MeSH

Cíl studie: V pilotním experimentu analyzovat metalothioneinu (MT) ve vzorcích moči pacientů se zhoubným nádorem prostaty (CaP). Metody: Vzorky byly analyzovány elektrochemicky metodou diferenční pulzní voltametrie (DPV) vBrdičkově základním elektrolytu. Získaná data byla vyhodnocena jako plochy pod křivkou (AUC). Koncentrace MT bylyvyhodnoceny metodou kalibrační křivky. Výsledky: Metallothioneiny jsou proteiny o molekulové hmotnosti kolem 10kDa. Jejich biologická role je především v udržování homeostázy iontů kovů v organismech. Analytické stanovení je komplikované. Mezi nejvhodnější metody patří elektrochemie. Uvedené metodické přístupy jsme aplikovali nasledování změn obsahu MT u pacientů s CaP a zbytnělou prostatou. V pilotním experimentu jsme zjistili, že průměrnáhladina MTu: a) kontrolní skupiny (n = 13) byla 2,9 ± 1,2 μg/mmol kreatininu; b) benigní hyperplazie prostaty 4,7 ± 1,7 μg/mmol kreatininu; c) CaP skupina (n = 9) 6,7 ± 1,5 μg/mmol kreatininu. Rozdíl mezi kontrolní skupinou a skupinouCaP byl statisticky průkazný (p = 0,0099). Mezi benigní hyperplazií prostaty a CaP byl také prokázán rozdíl (p =0,0928). Signály u pacientů s benigní hyperplazií prostaty (BHP) nevykazují statisticky významný rozdíl proti kontrolnískupině (p = 0,7869). Závěr: Získané prvotní výsledky naznačují, že hladiny MT lze v moči stanovit elektrochemicky. Mezi testovanými skupinami se podařilo prokázat rozdíly. Hladiny MT u pacientů s CaP byly zvýšené, ale musejí být dále detailněji studovány.

Aim: To analyse concentrations of metallothionein (MT) in urine samples of patients diagnosed with prostate cancer (CaP). Methods: Samples were electrochemically analysed by difference pulse voltametry (DPV) method in Brdička’s buffer. Acquired data were then evaluated as an area under the curve (AUC). Concentrations of MT were determinedby calibration curve method. Results: Metallothioneins are proteins with molecular weight about 10 kDa. Theirbiological significance lies in maintaining homeostasis of metal ions. Their analytical determination is complicated. One of the most effective determination methods is by electrochemistry. Previously mentioned methods were used tostudy the changes of MT concentrations of patients with CaP, and with benign prostate hyperplazia (BHP). Our pilotexperiment determined concentrations of MT in a) healthy controls (n = 13) was 2.9 ± 1.2 μg/mmol of creatinine, b) BHP was 4.7 ± 1.7 μg/mmol of creatinine, c) CaP group (n = 9) was 6.7 ± 1.5 μg/mmolof creatinine. Difference between healthy controls and CaP group was statistically significant (p = 0.0099). Differencebetween BHP and CaP group was also determined (p = 0.0928). Difference between BHP and healthy controls is notvery statistically significant (p = 0.7869). Conclusion: We were able to demonstrate differences between healthycontrols, BHP patients and CaP patients.Concentrations of MT in CaP patients were elevated, but they need to be studied in more detail.

• MeSH
• Adult MeSH
• Electrochemical Techniques MeSH
• Middle Aged MeSH
• Humans MeSH
• Metallothionein * urine   MeSH
• Adolescent MeSH
• Prostatic Neoplasms * urine   MeSH
• Pilot Projects MeSH
• Aged MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Male MeSH
• Aged MeSH

The use of knowledge from technetium radiochemistry (even from nuclear medicine applications) allows us to select an sorbent for 99mTc radionuclide sorption, which is hydroxyapatite. Using radioisotope indication, the 99mTcO4- sorption process on synthetic hydroxyapatite was studied by the batch method in the presence of SnCl2 and FeSO4 reducing agents. The complexing organic ligands' effect on the 99mTcO4- sorption under reducing conditions was investigated. In the presence of Sn2+ ions without the addition of organic ligand, the sorption percentage reached above 90% independently of the environment. In the presence of Fe2+ ions without the addition of organic ligand, the sorption of 99mTcO4- was significantly lower and was at approximately 6%, depending on the concentration of Fe2+ ions in solution. The effect of complexing organic ligands on the 99mTcO4- sorption on hydroxyapatite from the aqueous solution, acetate buffer and phosphate buffer decreases in the following order for Sn2+: oxalic acid > ethylenediaminetetraacetic acid > ascorbic acid. In the presence of Fe2+ ions without organic ligands, the sorption reached up to 15% depending on the composition of the solution. The addition of oxalic acid and ascorbic acid increased the sorption up to 80%. The ethylenediaminetetraacetic acid had no significant effect on the sorption of technetium on hydroxyapatite.

• MeSH
• Sodium Pertechnetate Tc 99m * MeSH
• Adsorption MeSH
• Edetic Acid MeSH
• Durapatite chemistry   MeSH
• Indicators and Reagents MeSH
• Oxalic Acid MeSH
• Ligands MeSH
• Technetium * analysis   MeSH
• Water MeSH
• Publication type
• Journal Article MeSH

The proper course and reproducibility of diagnostic techniques depend on narrowly defined reaction conditions, including the reaction pH. Nevertheless, numerous assays are affected by an inaccurately defined reaction pH. Buffers are sometimes suggested for use outside their useful pH ranges, which complicates the reproducibility of results because the buffering capacity is insufficient to retain the disclosed pH. Here, we focus on the comet assay lysis buffer. Comet assay is broadly used for quantifying DNA breaks in eukaryotic cells. The most widespread comet assay protocols employ lysis of the cells before electrophoresis in a buffer containing Triton X-100, a high concentration of NaCl, sodium sarcosinate, EDTA, and Tris, with some modifications. However, nearly all researchers report that they use Tris buffer at pH 10, and some report the pH of the Tris additive alone. Alternatively, others report the pH of the final lysis buffer. However, the lysis solution used in the comet assay is buffered at a pH outside the useful range of Tris. Tris-based buffers have a useful pH range of 7.0 - 9.0. The buffer composed of 10 mM Tris has pKa 8.10 at 25°C and 8.69 at 4°C. The cell lysis conditions used in nearly all modifications of comet assay protocols remain imprecise and uncritically employed. Despite the pH of the lysis buffer likely has negligible effect on the detection of DNA breaks, precise lysis conditions are highly important for the use of comet assay in the detection of base modifications, which are often unstable and sensitive to pH.

• MeSH
• DNA * MeSH
• Comet Assay methods   MeSH
• Hydrogen-Ion Concentration MeSH
• Humans MeSH
• DNA Damage * MeSH
• Reproducibility of Results MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

The development of singlet oxygen photosensitizers, which target specific cellular organelles, constitutes a pertinent endeavor to optimize the efficiency of photodynamic therapy. Targeting of the cell membrane eliminates the need for endocytosis of drugs that can lead to toxicity, intracellular degradation, or drug resistance. In this context, we utilized copper-free click chemistry to prepare a singlet oxygen photosensitizing complex, made of a molybdenum-iodine nanocluster stabilized by triazolate apical ligands. In phosphate-buffered saline, the complex formed nanoaggregates with a positive surface charge due to the protonatable amine function of the apical ligands. These nanoaggregates targeted cell membranes and caused an eminent blue-light phototoxic effect against HeLa cells at nanomolar concentrations, inducing apoptotic cell death, while having no dark toxicity at physiologically relevant concentrations. The properties of this complex were compared to those of a negatively charged parent complex to highlight the dominant effect of the nature of apical ligands on biological properties of the nanocluster. These two complexes also exerted (photo)antibacterial effects on several pathogenic strains in the form of planktonic cultures and biofilms. Overall, we demonstrated that the rational design of apical ligands toward cell membrane targeting leads to enhanced photodynamic efficiency.

• MeSH
• Cell Membrane MeSH
• HeLa Cells MeSH
• Iodine * pharmacology   MeSH
• Humans MeSH
• Ligands MeSH
• Molybdenum * pharmacology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH