A tubular microdialysis probe is made from polysulfone hollow fibre for human haemodialysis, which has an inner diameter of 200 μm and a thickness of 20 μm. Milk is deposited to the outer surface of the hollow fibre and allowed to dry to form a dry sample. The tubular probe is then connected to the syringe pump and microdialysis of the dry sample into 0.5 mol/L HCl as acceptor is performed. 2.5 μL of microdialysate is obtained and analyzed for inorganic cations by capillary electrophoresis with contactless conductivity detection. Baseline separation of NH4+, K+, Ca2+, Na+, Mg2+, Li+ is achieved in 5.5 mol/L acetic acid as background electrolyte using a fused silica capillary with inner diameter of 25 μm and length of 31.5 cm. The reproducibility of dry sample microdialysis including CE analysis for peak area ranges from 2.4 to 3.9 % after normalization to Li+ as internal standard.
- MeSH
- Electrophoresis, Capillary * instrumentation methods MeSH
- Cations * analysis MeSH
- Microdialysis * instrumentation methods MeSH
- Milk * chemistry MeSH
- Cattle MeSH
- Animals MeSH
- Check Tag
- Cattle MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Evaluation Study MeSH
Developing bioinspired materials to convert sunlight into electricity efficiently is paramount for sustainable energy production. Fluorescent proteins are promising candidates as photoactive materials due to their high fluorescence quantum yield and absorption extinction coefficients in aqueous media. However, developing artificial bioinspired photosynthetic systems requires a detailed understanding of molecular interactions and energy transfer mechanisms in the required operating conditions. Here, the supramolecular self-assembly and photophysical properties of fluorescent proteins complexed with organic dyes are investigated in aqueous media. Supercharged mGreenLantern protein, mutated to have a charge of +22, is complexed together with anionic zinc phthalocyanines having 4 or 16 carboxylate groups. The structural characterization reveals a strong electrostatic interaction between the moieties, accompanied by partial conformational distortion of the protein structure, yet without compromising the mGreenLantern chromophore integrity as suggested by the lack of emission features related to the neutral form of the chromophore. The self-assembled biohybrid shows a total quenching of protein fluorescence, in favor of an energy transfer process from the protein to the phthalocyanine, as demonstrated by fluorescence lifetime and ultrafast transient absorption measurements. These results provide insight into the rich photophysics of fluorescent protein-dye complexes, anticipating their applicability as water-based photoactive materials.
- MeSH
- Anions chemistry MeSH
- Fluorescent Dyes chemistry MeSH
- Spectrometry, Fluorescence MeSH
- Indoles * chemistry metabolism MeSH
- Isoindoles MeSH
- Luminescent Proteins * chemistry metabolism MeSH
- Organometallic Compounds * chemistry metabolism MeSH
- Energy Transfer MeSH
- Zinc Compounds MeSH
- Publication type
- Journal Article MeSH
OBJECTIVES: Differentiating true progression or recurrence (TP/TR) from therapy-related changes (TRC) is complex in brain tumours. Amide proton transfer-weighted (APT) imaging is a chemical exchange saturation transfer (CEST) MRI technique that may improve diagnostic accuracy during radiological follow-up. This systematic review and meta-analysis elucidated the level of evidence and details of state-of-the-art imaging for APT-CEST in glioma and brain metastasis surveillance. METHODS: PubMed, EMBASE, Web of Science, and Cochrane Library were systematically searched for original articles about glioma and metastasis patients who received APT-CEST imaging for suspected TP/TR within 2 years after (chemo)radiotherapy completion. Modified Quality Assessment of Diagnostic Accuracy Studies-2 criteria were applied. A meta-analysis was performed to pool results and to compare subgroups. RESULTS: Fifteen studies were included for a narrative synthesis, twelve of which (500 patients) were deemed sufficiently homogeneous for a meta-analysis. Magnetisation transfer ratio asymmetry performed well in gliomas (sensitivity 0.88 [0.82-0.92], specificity 0.84 [0.72-0.91]) but not in metastases (sensitivity 0.64 [0.38-0.84], specificity 0.56 [0.33-0.77]). APT-CEST combined with conventional/advanced MRI rendered 0.92 [0.86-0.96] and 0.88 [0.72-0.95] in gliomas. Tumour type, TR prevalence, sex, and acquisition protocol were sources of significant inter-study heterogeneity in sensitivity (I2 = 62.25%; p < 0.01) and specificity (I2 = 66.31%; p < 0.001). CONCLUSION: A growing body of literature suggests that APT-CEST is a promising technique for improving the discrimination of TP/TR from TRC in gliomas, with limited data on metastases. CLINICAL RELEVANCE STATEMENT: This meta-analysis identified a utility for APT-CEST imaging regarding the non-invasive discrimination of brain tumour progression from therapy-related changes, providing a critical evaluation of sequence parameters and cut-off values, which can be used to improve response assessment and patient outcome. KEY POINTS: Therapy-related changes mimicking progression complicate brain tumour treatment. Amide proton imaging improves the non-invasive discrimination of glioma progression from therapy-related changes. Magnetisation transfer ratio asymmetry measurement seems not to have added value in brain metastases.
- MeSH
- Amides * MeSH
- Diagnosis, Differential MeSH
- Glioma * diagnostic imaging pathology MeSH
- Humans MeSH
- Neoplasm Recurrence, Local diagnostic imaging MeSH
- Magnetic Resonance Imaging * methods MeSH
- Brain Neoplasms * diagnostic imaging secondary MeSH
- Disease Progression * MeSH
- Protons MeSH
- Sensitivity and Specificity MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Meta-Analysis MeSH
- Systematic Review MeSH
In this study, simple oil-in-water emulsions (O/W) and multiple O/W/O emulsions were employed as carriers for a curcumin delivery system. The stability of emulsions was evaluated using DSC (differential scanning calorimetry), accompanied by particle size measurement by DLS (dynamic light scattering) and rheological analysis. The amount of freezable water (Wfs) in O/W emulsion was determined to be 80.4%, while that in O/W/O emulsion was 23.7%. Multiple emulsions had a more complex structure than simple emulsions, being characterized by higher stability with predominant loss modulus over storage modulus (G" > G'). The mean surface diameter for O/W emulsion was 198.7 ± 9.8 nm, being approximately two times lower than that for multiple emulsions. Curcumin in vitro digestibility was observed for both emulsions and, additionally, the digestibility of fresh and dried curcuma root powders was investigated. Multiple emulsions were found to be a superior matrix for curcumin delivery, with higher stability and emulsion digestibility of 50.6% for the stomach and small intestine. In vitro digestion of dried curcuma powders and curcuma root samples was monitored by HPLC (high-performance liquid chromatography). The DMD (dry matter digestibility) for dried curcuma powders ranged between 52.9% to 78.8%, and for fresh curcuma (KF) was 95.5%.
OBJECTIVES: This study aimed to investigate the impact of bleaching agents based on carbamide or hydrogen peroxide on dental ceramics in vitro, utilizing scanning electron microscopy (SEM) and elemental analysis via inductively coupled plasma optical emission spectroscopy (ICP-OES). METHODS: CAD/CAM ceramics (IPS e.max®CAD, IPS Empress®CAD, Vitablocs® Mark II, Celtra Duo, and inCoris TZI) were treated with bleaching agents using either 10%, 20%, 30% carbamide peroxide or with 35%, and 40% hydrogen peroxide. RESULTS: Surface elemental release was not significantly affected by the type or concentration of bleaching agent (p>0.05). Ion release in feldspathic ceramics was significantly higher than in other ceramic materials (p⟨0.0001). Microstructural surface changes were observed in all materials except for lithium disilicate and zirconia-reinforced lithium silicate ceramics. CONCLUSIONS: All bleaching agents tested in this study showed a similar impact within each material type tested regarding total mass loss, elemental composition, or surface structure. CLINICAL RELEVANCE: Lithium disilicate and zirconia-reinforced lithium silicate ceramics were the most resistant to bleaching agents. In contrast, feldspathic ceramic showed the highest ion release and surface deterioration when exposed to all bleaching agents tested.
- MeSH
- Computer-Aided Design * MeSH
- Carbamide Peroxide * chemistry MeSH
- Ceramics * chemistry MeSH
- Tooth Bleaching Agents * chemistry MeSH
- Microscopy, Electron, Scanning MeSH
- Hydrogen Peroxide * chemistry MeSH
- Surface Properties MeSH
- Materials Testing MeSH
- Zirconium chemistry MeSH
- Dental Porcelain * chemistry MeSH
- Publication type
- Journal Article MeSH
145 stran : ilustrace ; 30 cm
Směrnice, které se zaměřují na proces sterilizace zdravotnických prostředků pomocí páry a tepla. Určeno odborné veřejnosti.
- MeSH
- Steam MeSH
- Reproducibility of Results MeSH
- Quality Control MeSH
- Health Care Sector MeSH
- Sterilization MeSH
- Hot Temperature MeSH
- Equipment and Supplies MeSH
- Publication type
- Guideline MeSH
- Geographicals
- Czech Republic MeSH
- Europe MeSH
- Conspectus
- Metrologie. Standardizace
- NML Fields
- technika lékařská, zdravotnický materiál a protetika
Thyroid hormones (TH) are essential for vertebrate development, growth, and metabolism. The increasing prevalence of anthropogenic chemicals with TH-disrupting potential highlights the urgent need for advanced methods to assess their impact on TH homeostasis. Inhibition of the sodium-iodide symporter (NIS) has been identified as a key molecular initiating event disrupting the TH system across species, with significant relevance for diagnostic and therapeutic applications in various carcinomas. This study presents in vitro bioassays for evaluating the effects of compounds on iodide uptake into cells, a critical step in TH production mediated by NIS. Two novel stably transfected human cell lines overexpressing human NIS were employed along with a rat thyroid cell model FRTL-5, using colorimetric Sandell-Kolthoff (SK) reaction for iodide detection. The results from 23 model compounds demonstrate comparability across various in vitro models and radioactivity-based assays. To enhance physiological relevance, an external biotransformation system (BTS) was integrated and optimized for live-cell compatibility without inducing cytotoxicity or interfering with the assay. Compounds identified as NIS inhibitors were evaluated using the BTS-augmented assay, which revealed that metabolic activity mitigated the inhibitory effects of some chemicals. The augmented assay exhibited strong concordance with in vivo and in silico biotransformation data. Protein sequence alignment confirmed high conservation of NIS functional domains across vertebrates, reinforcing the cross-species applicability of the findings. The SK-based NIS assay, with optional BTS integration, represents a sensitive, robust, and high-throughput amendable alternative to radioactivity-based methods, for characterizing the impacts of individual compounds and complex environmental mixtures on TH homeostasis.
- MeSH
- Biological Assay methods MeSH
- Biotransformation MeSH
- Cell Line MeSH
- Endocrine Disruptors * toxicity MeSH
- Thyroid Hormones metabolism MeSH
- Iodides * metabolism MeSH
- Rats MeSH
- Humans MeSH
- Thyroid Gland metabolism drug effects cytology MeSH
- Symporters * antagonists & inhibitors metabolism genetics MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
This study aimed to determine the paraoxonase activity and prooxidant-antioxidant balance in the brain tissue of Wistar rats following subacute treatment with selected K-oximes. Each K-oxime was administered intramuscularly (0.1 LD50/kg) twice per week for four weeks, and 7 days after the last treatment, the paraoxonase activity (PON1), the prooxidant-antioxidant balance (PAB), the levels of superoxide anion radical (O2•-), the concentration of nitrite (NO2-) and the content of free protein thiol groups in the brain homogenates were evaluated. The PON1 and PAB activity were significantly reduced in almost all oxime-treated groups (p < 0.01 and p < 0.001, respectively). The concentrations of O2•- were significantly increased in the obidoxime-, K048-, K074- and K075-treated groups (p < 0.001), while the levels of NO2- was significantly decreased in asoxime-, obidoxime-, K074 and K075-treated rats (p < 0.01, p < 0.001, respectively). The content of Thiol groups was significantly elevated in all oxime-treated groups (p < 0.001). Continuing our previously published data, these results confirmed that applied K-oximes improved the oxidative status and further harmful systemic effects of rats after subacute administration.
- MeSH
- Antioxidants * metabolism MeSH
- Aryldialkylphosphatase * metabolism MeSH
- Nitrites metabolism MeSH
- Rats MeSH
- Brain * drug effects metabolism enzymology MeSH
- Oximes * pharmacology administration & dosage MeSH
- Rats, Wistar MeSH
- Sulfhydryl Compounds metabolism MeSH
- Superoxides metabolism MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Bacterial proton pumps, proteorhodopsins (PRs), are a major group of light-driven membrane proteins found in marine bacteria. They are functionally and structurally distinct from archaeal and eukaryotic proton pumps. To elucidate the proton transfer mechanism by PRs and understand the differences to nonbacterial pumps on a molecular level, high-resolution structures of PRs' functional states are needed. In this work, we have determined atomic-resolution structures of MAR, a PR from marine actinobacteria, in various functional states, notably the challenging late O intermediate state. These data and information from recent atomic-resolution structures on an archaeal outward proton pump bacteriorhodopsin and bacterial inward proton pump xenorhodopsin allow for deducing key universal elements for light-driven proton pumping. First, long hydrogen-bonded chains characterize proton pathways. Second, short hydrogen bonds allow proton storage and inhibit their backflow. Last, the retinal Schiff base is the active proton donor and acceptor to and from hydrogen-bonded chains.
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
