PURPOSE: Medium vessel occlusions (MeVOs) can be challenging to detect on imaging. Multiphase computed tomography angiography (mCTA) has been shown to improve large vessel occlusion (LVO) detection and endovascular treatment (EVT) selection. The aims of this study were to determine if mCTA-derived tissue maps can (1) accurately detect MeVOs and (2) predict infarction on 24-h follow-up imaging with comparable accuracy to CT perfusion (CTP). METHODS: Two readers assessed mCTA tissue maps of 116 ischemic stroke patients (58 MeVOs, 58 non-MeVOs) and determined by consensus: (1) MeVO (yes/no) and (2) occlusion site, blinded to clinical or imaging data. Sensitivity, specificity, and area under the curve (AUC) for MeVO detection were estimated in comparison to reference standards of (1) expert readings of baseline mCTA and (2) CTP maps. Volumetric and spatial agreement between mCTA- and CTP-predicted infarcts was assessed using concordance/intraclass correlation and Dice coefficients. Interrater agreement for MeVO detection on mCTA tissue maps was estimated with Cohen's kappa. RESULTS: MeVO detection from mCTA-derived tissue maps had a sensitivity of 91% (95% CI: 80-97), specificity of 82% (95% CI: 70-90), and AUC of 0.87 (95% CI: 0.80-0.93) compared to expert reads of baseline mCTA. Interrater reliability was good (0.72, 95% CI: 0.60-0.85). Compared to CTP maps, sensitivity was 87% (95% CI: 75-95), specificity was 78% (95%CI: 65-88), and AUC was 0.83 (95% CI: 0.76-0.90). The mean difference between mCTA- and CTP-predicted final infarct volume was 4.8 mL (limits of agreement: - 58.5 to 68.1) with a Dice coefficient of 33.5%. CONCLUSION: mCTA tissue maps can be used to reliably detect MeVO stroke and predict tissue fate.
- MeSH
- Stroke * diagnostic imaging therapy MeSH
- Computed Tomography Angiography methods MeSH
- Cytidine Triphosphate MeSH
- Brain Ischemia * therapy MeSH
- Humans MeSH
- Cerebral Angiography methods MeSH
- Tomography, X-Ray Computed methods MeSH
- Reproducibility of Results MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Computed tomography perfusion (CTP) is a functional examination of brain tissue that characterises the state of cerebral perfusion and provides information about the current status of the circulation. CTP can improve diagnostic accuracy of ischemic stroke. Published studies showed that perfusion imaging improves the prognosis of patients with acute ischemic stroke in anterior circulation and allows patients to be referred for treatment outside the time window for administration of intravenous thrombolysis (IVT) or mechanical thrombectomy (MT). In this review we discuss technical aspects of CTP, clinical significance of CTP in anterior circulation stroke (ACS) and its role in diagnostics of stroke mimics.
- MeSH
- Cytidine Triphosphate MeSH
- Ischemic Stroke * diagnostic imaging therapy MeSH
- Brain Ischemia * diagnostic imaging therapy MeSH
- Humans MeSH
- Perfusion MeSH
- Tomography, X-Ray Computed methods MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
We synthesized a small library of eighteen 5-substituted pyrimidine or 7-substituted 7-deazapurine nucleoside triphosphates bearing methyl, ethynyl, phenyl, benzofuryl or dibenzofuryl groups through cross-coupling reactions of nucleosides followed by triphosphorylation or through direct cross-coupling reactions of halogenated nucleoside triphosphates. We systematically studied the influence of the modification on the efficiency of T7 RNA polymerase catalyzed synthesis of modified RNA and found that modified ATP, UTP and CTP analogues bearing smaller modifications were good substrates and building blocks for the RNA synthesis even in difficult sequences incorporating multiple modified nucleotides. Bulky dibenzofuryl derivatives of ATP and GTP were not substrates for the RNA polymerase. In the case of modified GTP analogues, a modified procedure using a special promoter and GMP as initiator needed to be used to obtain efficient RNA synthesis. The T7 RNA polymerase synthesis of modified RNA can be very efficiently used for synthesis of modified RNA but the method has constraints in the sequence of the first three nucleotides of the transcript, which must contain a non-modified G in the +1 position.
- MeSH
- Adenosine Triphosphate analogs & derivatives metabolism MeSH
- Bacteriophage T7 enzymology MeSH
- Cytidine Triphosphate analogs & derivatives metabolism MeSH
- DNA-Directed RNA Polymerases metabolism MeSH
- Purine Nucleosides chemistry metabolism MeSH
- Purines chemistry metabolism MeSH
- Pyrimidine Nucleosides chemistry metabolism MeSH
- RNA chemistry metabolism MeSH
- Substrate Specificity MeSH
- Uridine Triphosphate analogs & derivatives metabolism MeSH
- Viral Proteins metabolism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Comparative Study MeSH
Human papillomavirus (HPV) is responsible for cervical cancer, and its role in head and neck carcinoma has been reported. No drug is approved for the treatment of HPV-related diseases but cidofovir (CDV) exhibits selective antiproliferative activity. In this study, we analyzed the effects of CDV-resistance (CDVR) in two HPV(+) (SiHaCDV and HeLaCDV) and one HPV(-) (HaCaTCDV) tumor cell lines. Quantification of CDV metabolites and analysis of the sensitivity profile to chemotherapeutics was performed. Transporters expression related to multidrug-resistance (MRP2, P-gp, BCRP) was also investigated. Alterations of CDV metabolism in SiHaCDV and HeLaCDV, but not in HaCaTCDV, emerged via impairment of UMP/CMPK1 activity. Mutations (P64T and R134M) as well as down-regulation of UMP/CMPK1 expression were observed in SiHaCDV and HeLaCDV, respectively. Altered transporters expression in SiHaCDV and/or HeLaCDV, but not in HaCaTCDV, was also noted. Taken together, these results indicate that CDVR in HPV(+) tumor cells is a multifactorial process.
- MeSH
- ATP-Binding Cassette Transporters biosynthesis MeSH
- Drug Resistance, Neoplasm genetics MeSH
- Cytidine Triphosphate biosynthesis MeSH
- Cytosine analogs & derivatives pharmacology MeSH
- Phosphorylation MeSH
- HeLa Cells MeSH
- Papillomavirus Infections drug therapy MeSH
- Humans MeSH
- Microbial Sensitivity Tests MeSH
- Cell Line, Tumor MeSH
- Uterine Cervical Neoplasms drug therapy pathology virology MeSH
- Nucleoside-Phosphate Kinase biosynthesis metabolism MeSH
- Organophosphonates pharmacology MeSH
- Papillomaviridae MeSH
- Solute Carrier Proteins biosynthesis MeSH
- Uridine Triphosphate biosynthesis MeSH
- Check Tag
- Humans MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
A new CZE method was developed for the determination of 12 purine and pyrimidine nucleotides, two adenine coenzymes and their reduced forms, and acetyl coenzyme A in various cell extracts. As the concentration levels of these metabolites in living cells are low; CZE was combined with field-enhanced sample stacking. As a result, the separation conditions were optimised to achieve a suitable resolution at the relatively high sample volume provided by this on-line pre-concentration technique. The optimum BGE was 150 mM glycine buffer (pH 9.5). Samples were introduced hydrodynamically using a pressure of 35 mbar (3.5 kPa) for 25 s, and data were collected at a detection wavelength of 260 nm. An applied voltage of 30 kV (positive polarity) and capillary temperature of 25°C gave the best separation of these compounds. The optimised method was validated by determining the linearity, sensitivity and repeatability and it was successfully applied for the analysis of extracts from Paracoccus denitrificans bacteria and from stem cells.
- MeSH
- Acetyl Coenzyme A analysis MeSH
- Adenosine Triphosphate analysis MeSH
- Chemistry Techniques, Analytical methods standards MeSH
- Cytidine Triphosphate analysis MeSH
- Embryonic Stem Cells chemistry MeSH
- Guanosine Triphosphate analysis MeSH
- Humans MeSH
- Limit of Detection MeSH
- Paracoccus denitrificans chemistry MeSH
- Reproducibility of Results MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Molecular dynamics simulations of complexes between Norwalk virus RNA dependent RNA polymerase and its natural CTP and 2dCTP (both containing the O5'-C5'-C4'-O4' sequence of atoms bridging the triphosphate and sugar moiety) or modified coCTP (C5'-O5'-C4'-O4'), cocCTP (C5'-O5'-C4'-C4'') substrates were produced by means of CUDA programmable graphical processing units and the ACEMD software package. It enabled us to gain microsecond MD trajectories clearly showing that similar nucleoside triphosphates can bind surprisingly differently into the active site of the Norwalk virus RNA dependent RNA polymerase. It corresponds to their different modes of action (CTP-substrate, 2dCTP-poor substrate, coCTP-chain terminator, cocCTP-inhibitor). Moreover, extremely rare events-as repetitive pervasion of Arg182 into a potentially reaction promoting arrangement-were captured.
- MeSH
- Cytidine Triphosphate analogs & derivatives metabolism MeSH
- Caliciviridae Infections virology MeSH
- Humans MeSH
- Norovirus enzymology metabolism MeSH
- RNA-Dependent RNA Polymerase metabolism MeSH
- Molecular Dynamics Simulation MeSH
- Molecular Docking Simulation MeSH
- Substrate Specificity MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- MeSH
- Adenosine Triphosphate analogs & derivatives analysis chemistry MeSH
- Cytidine Triphosphate analogs & derivatives analysis chemistry MeSH
- DNA-Directed DNA Polymerase chemistry MeSH
- Electrochemistry MeSH
- Financing, Organized MeSH
- Boronic Acids chemistry MeSH
- Molecular Structure MeSH
- Oligonucleotides chemical synthesis chemistry MeSH
- Uridine Triphosphate analogs & derivatives analysis chemistry MeSH
