MicroRNA-298 determines the radio-resistance of colorectal cancer cells by directly targeting human dual-specificity tyrosine(Y)-regulated kinase 1A.

BACKGROUND: Radiotherapy stands as a promising therapeutic modality for colorectal cancer (CRC); yet, the formidable challenge posed by radio-resistance significantly undermines its efficacy in achieving CRC remission. AIM: To elucidate the role played by microRNA-298 (miR-298) in CRC radio-resistance. METHODS: To establish a radio-resistant CRC cell line, HT-29 cells underwent exposure to 5 gray ionizing radiation that was followed by a 7-d recovery period. The quantification of miR-298 levels within CRC cells was conducted through quantitative RT-PCR, and protein expression determination was realized through Western blotting. Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and proliferation by clonogenic assay. Radio-induced apoptosis was discerned through flow cytometry analysis. RESULTS: We observed a marked upregulation of miR-298 in radio-resistant CRC cells. MiR-298 emerged as a key determinant of cell survival following radiation exposure, as its overexpression led to a notable reduction in radiation-induced apoptosis. Intriguingly, miR-298 expression exhibited a strong correlation with CRC cell viability. Further investigation unveiled human dual-specificity tyrosine(Y)-regulated kinase 1A (DYRK1A) as miR-298's direct target. CONCLUSION: Taken together, our findings underline the role played by miR-298 in bolstering radio-resistance in CRC cells by means of DYRK1A downregulation, thereby positioning miR-298 as a promising candidate for mitigating radio-resistance in CRC.

Endophilin A2 controls touch and mechanical allodynia via kinesin-mediated Piezo2 trafficking.

BACKGROUND: Tactile and mechanical pain are crucial to our interaction with the environment, yet the underpinning molecular mechanism is still elusive. Endophilin A2 (EndoA2) is an evolutionarily conserved protein that is documented in the endocytosis pathway. However, the role of EndoA2 in the regulation of mechanical sensitivity and its underlying mechanisms are currently unclear. METHODS: Male and female C57BL/6 mice (8-12 weeks) and male cynomolgus monkeys (7-10 years old) were used in our experiments. Nerve injury-, inflammatory-, and chemotherapy-induced pathological pain models were established for this study. Behavioral tests of touch, mechanical pain, heat pain, and cold pain were performed in mice and nonhuman primates. Western blotting, immunostaining, co-immunoprecipitation, proximity ligation and patch-clamp recordings were performed to gain insight into the mechanisms. RESULTS: The results showed that EndoA2 was primarily distributed in neurofilament-200-positive (NF200+) medium-to-large diameter dorsal root ganglion (DRG) neurons of mice and humans. Loss of EndoA2 in mouse NF200+ DRG neurons selectively impaired the tactile and mechanical allodynia. Furthermore, EndoA2 interacted with the mechanically sensitive ion channel Piezo2 and promoted the membrane trafficking of Piezo2 in DRG neurons. Moreover, as an adaptor protein, EndoA2 also bound to kinesin family member 5B (KIF5B), which was involved in the EndoA2-mediated membrane trafficking process of Piezo2. Loss of EndoA2 in mouse DRG neurons damaged Piezo2-mediated rapidly adapting mechanically activated currents, and re-expression of EndoA2 rescued the MA currents. In addition, interference with EndoA2 also suppressed touch sensitivity and mechanical hypersensitivity in nonhuman primates. CONCLUSIONS: Our data reveal that the KIF5B/EndoA2/Piezo2 complex is essential for Piezo2 trafficking and for sustaining transmission of touch and mechanical hypersensitivity signals. EndoA2 regulates touch and mechanical allodynia via kinesin-mediated Piezo2 trafficking in sensory neurons. Our findings identify a potential new target for the treatment of mechanical pain.

ATF4 inhibits TRPV4 function and controls itch perception in rodents and nonhuman primates.

ABSTRACT: Acute and chronic itch are prevalent and incapacitating, yet the neural mechanisms underlying both acute and chronic itch are just starting to be unraveled. Activated transcription factor 4 (ATF4) belongs to the ATF/CREB transcription factor family and primarily participates in the regulation of gene transcription. Our previous study has demonstrated that ATF4 is expressed in sensory neurons. Nevertheless, the role of ATF4 in itch sensation remains poorly understood. Here, we demonstrate that ATF4 plays a significant role in regulating itch sensation. The absence of ATF4 in dorsal root ganglion (DRG) neurons enhances the itch sensitivity of mice. Overexpression of ATF4 in sensory neurons significantly alleviates the acute and chronic pruritus in mice. Furthermore, ATF4 interacts with the transient receptor potential cation channel subfamily V member 4 (TRPV4) and inhibits its function without altering the expression or membrane trafficking of TRPV4 in sensory neurons. In addition, interference with ATF4 increases the itch sensitivity in nonhuman primates and enhances TRPV4 currents in nonhuman primates DRG neurons; ATF4 and TRPV4 also co-expresses in human sensory neurons. Our data demonstrate that ATF4 controls pruritus by regulating TRPV4 signaling through a nontranscriptional mechanism and identifies a potential new strategy for the treatment of pathological pruritus.

ANKRD22 aggravates sepsis-induced ARDS and promotes pulmonary M1 macrophage polarization.

Acute respiratory distress syndrome (ARDS) is independently associated with a poor prognosis in patients with sepsis. Macrophage M1 polarization plays an instrumental role in this process. Therefore, the exploration of key molecules affecting acute lung injury and macrophage M1 polarization may provide therapeutic targets for the treatment of septic ARDS. Here, we identified that elevated levels of Ankyrin repeat domain-containing protein 22 (ANKRD22) were associated with poor prognosis and more pronounced M1 macrophage polarization in septic patients by analyzing high-throughput data. ANKRD22 expression was also significantly upregulated in the alveolar lavage fluid, peripheral blood, and lung tissue of septic ARDS model mice. Knockdown of ANKRD22 significantly attenuated acute lung injury in mice with sepsis-induced ARDS and reduced the M1 polarization of lung macrophages. Furthermore, deletion of ANKRD22 in macrophages inhibited M1 macrophage polarization and reduced levels of phosphorylated IRF3 and intracellular interferon regulatory factor 3 (IRF3) expression, while re-expression of ANKRD22 reversed these changes. Further experiments revealed that ANKRD22 promotes IRF3 activation by binding to mitochondrial antiviral-signaling protein (MAVS). In conclusion, these findings suggest that ANKRD22 promotes the M1 polarization of lung macrophages and exacerbates sepsis-induced ARDS.

Porous Tellurium-Doped Ruthenium Dioxide Nanotubes for Enhanced Acidic Water Oxidation.

Electrocatalysts with high activity and durability for acidic oxygen evolution reaction (OER) play a crucial role in achieving cost-effective hydrogen production via proton exchange membrane water electrolysis. A novel electrocatalyst, Te-doped RuO2 (Te-RuO2 ) nanotubes, synthesized using a template-directed process, which significantly enhances the OER performance in acidic media is reported. The Te-RuO2 nanotubes exhibit remarkable OER activity in acidic media, requiring an overpotential of only 171 mV to achieve an anodic current density of 10 mA cm-2 . Furthermore, they maintain stable chronopotentiometric performance under 10 mA cm-2 in acidic media for up to 50 h. Based on the experimental results and density functional calculations, this significant improvement in OER performance to the synergistic effect of large specific surface area and modulated electronic structure resulting from the doping of Te cations is attributed.

Efficient and stable acidic CO2 electrolysis to formic acid by a reservoir structure design.

Electrochemical synthesis of valuable chemicals and feedstocks through carbon dioxide (CO2) reduction in acidic electrolytes can surmount the considerable CO2 loss in alkaline and neutral conditions. However, achieving high productivity, while operating steadily in acidic electrolytes, remains a big challenge owing to the severe competing hydrogen evolution reaction. Here, we show that vertically grown bismuth nanosheets on a gas-diffusion layer can create numerous cavities as electrolyte reservoirs, which confine in situ-generated hydroxide and potassium ions and limit inward proton diffusion, producing locally alkaline environments. Based on this design, we achieve formic acid Faradaic efficiency of 96.3% and partial current density of 471 mA cm-2 at pH 2. When operated in a slim continuous-flow electrolyzer, the system exhibits a full-cell formic acid energy efficiency of 40% and a single pass carbon efficiency of 79% and performs steadily over 50 h. We further demonstrate the production of pure formic acid aqueous solution with a concentration of 4.2 weight %.

Colorectal liver metastases: Correlations of contrast-enhanced ultrasound features with tumor clinicopathological factors and clinical outcomes following conversion therapy.

OBJECTIVE: To explore the prognostic impact of contrast-enhanced ultrasound (CEUS) features for initially unresectable colorectal liver metastases (CLMs) in a clinical setting of conversion therapy. METHODS: Between March 2015 and November 2020, consecutive patients with CLMs who received conversion treatment were prospectively enrolled. All participants underwent liver CEUS at baseline. The primary endpoint was conversion resection rate (R0 and overall resection). Secondary endpoints were objective response rate (ORR), overall survival (OS), and progression-free survival (PFS). RESULTS: 104 participants who completed conversion treatment were included. CEUS enhancement pattern was correlated with index lesion (size and echogenicity), primary (site, differentiation, perineural invasion, and RAS genotype) and serum (CA19-9 level) characteristics (P = <0.001-0.016). CEUS enhancement pattern was significantly associated with R0 resection rate, ORR, PFS, and OS (P = 0.001-0.049), whereas enhancement degree was associated with PFS and OS (P = 0.043 and 0.045). Multivariate analysis showed that heterogeneous enhancement independently predicted R0 and overall resection (P = 0.028 and 0.024) while rim-like enhancement independently predicted ORR and OS (P = 0.009 and 0.026). CONCLUSION: CEUS enhancement pattern was significantly associated with tumor characteristics and clinical outcomes following conversion therapy, and thus might be of prognosis impact for initially unresectable CLMs.

An intramolecular vibrationally excited intermolecular potential energy surface and predicted 2OH overtone spectroscopy of H2O-Kr.

A new five-dimensional potential energy surface (PES) for H2O-Kr which explicitly includes the intramolecular 2OH overtone state of the H2O monomer is presented. The intermolecular potential energies were evaluated using explicitly correlated coupled cluster theory [CCSD(T)-F12] with a large basis set. Four vibrationally averaged analytical intermolecular PESs for H2O-Kr with H2O molecules in its |00+〉, |02+〉, |02-〉, and |11+〉 states are obtained by fitting to the multi-dimensional Morse/Long-Range potential function form. Each vibrationally averaged PES fitted to 578 points has root-mean-square (RMS) deviations smaller than 0.14 cm-1 and requires only 58 parameters. The combined radial discrete variable representation/angular finite basis representation method and the Lanczos algorithm were employed to calculate the rovibrational energy levels for |00+〉, |02+〉, |02-〉, and |11+〉 states of the H2O-Kr complexes. The calculated |02-〉Πf/e(101) ← |00+〉Σe(000) and |02+〉Πf/e(110) ← |00+〉Σe(101) infrared transitions are in excellent agreement with the experimental values with RMS discrepancies being only 0.007 and 0.016 cm-1, respectively. These analytical PESs can be used to provide reliable theoretical guidance for future infrared overtone spectroscopy of H2O-Kr.

Gerhardtite as a Precursor to an Efficient CO-to-Acetate Electroreduction Catalyst.

Carbon-carbon coupling electrochemistry on a conventional copper (Cu) catalyst still undergoes low selectivity among many different multicarbon (C2+) chemicals, posing a grand challenge to achieve a single C2+ product. Here, we demonstrate a laser irradiation synthesis of a gerhardtite mineral, Cu2(OH)3NO3, as a catalyst precursor to make a Cu catalyst with abundant stacking faults under reducing conditions. Such structural perturbation modulates electronic microenvironments of Cu, leading to improved d-electron back-donation to the antibonding orbital of *CO intermediates and thus strengthening *CO adsorption. With increased *CO coverage on the defect-rich Cu, we report an acetate selectivity of 56 ± 2% (compared to 31 ± 1% for conventional Cu) and a partial current density of 222 ± 7 mA per square centimeter in CO electroreduction. When run at 400 mA per square centimeter for 40 h in a flow reactor, this catalyst produces 68.3 mmol of acetate throughout. This work highlights the value of a Cu-containing mineral phase in accessing suitable structures for improved selectivity to a single desired C2+ product.

Vitrectomy for retinal detachment associated with macular hole: Prognostic factor analysis under different axial length conditions.

PURPOSE: To identify prognostic factors for complete anatomical success (CAS) under different axial length (AL) conditions after vitrectomy plus internal limiting membrane (ILM) peeling for retinal detachment associated with macular hole (MHRD). METHODS: This retrospective study included 243 patients (251 eyes) with MHRD who underwent primary vitrectomy plus ILM peeling. Multivariate logistic regression explored prognostic factors for CAS in AL <30 mm and ≥ 30 mm groups. RESULTS: Overall, 113 eyes (45.0% of 251) exhibited complete CAS after initial surgery. Eyes with CAS had greater best-corrected visual acuity improvement than eyes without CAS (p < 0.001). CAS was more common in eyes with AL < 30 mm (50.3% of 155) than in eyes with AL ≥ 30 mm (36.5%, 35/96; p = 0.032). In the AL < 30 mm group, CAS was associated with ILM insertion (odds ratio [OR], 2.824, 95% confidence interval [CI], 1.189-6.710; p = 0.019), silicone oil (SO)/perfluoropropane (C3F8) tamponade (SO: OR, 0.408, 95% CI, 0.191-0.873; C3F8: OR, 2.448, 95% CI, 1.145-5.234; p = 0.021) and staphyloma (OR, 0.318, 95% CI, 0.143-0.707; p = 0.005). In the AL ≥30 mm group, CAS was associated with ILM insertion (OR, 11.621, 95% CI, 2.557-52.813; p = 0.001), SO /C3F8 tamponade (SO: OR, 5.305, 95% CI, 1.206-23.334; C3F8: OR, 0.188, 95% CI, 0.043-0.829; p = 0.027) and age (OR, 0.928, 95% CI, 0.876-0.983; p = 0.011). CONCLUSION: Vitrectomy plus ILM peeling can effectively treat MHRD but has limited efficacy in eyes with AL ≥ 30 mm. ILM insertion was associated with more frequent CAS at any AL. C3F8 tamponade yielded better outcomes with AL < 30 mm; SO tamponade yielded better outcomes with AL ≥ 30 mm.

Epidemiological and Molecular Study on Tick-Borne Pathogens in Argun Port Area Near the Chinese-Russian Border.

Objective: We aim to investigate the species composition of ticks and the pathogen characteristics they carry in the Argun port area of the China-Russia border. Materials and Methods: Ticks were collected in surrounding grassland, mixed forest land, and other different habitats around the Argun port area at the Sino-Russian Border of Inner Mongolia in China in April 2019. The presence of 16 potential pathogens, including Yersinia Pestis, Francisella tularensis, Coxiella burnetii (Cb), Anaplasma sp. (Ap), spotted fever group rickettsiae (SFG Rk), Borrelia sp. (Bl), Leptospira, Bartonella spp., Babesia, Crimean-Congo hemorrhagic fever virus, tick-borne encephalitis virus, Bhanja virus, West Nile Virus, severe fever with thrombocytopenia syndrome bunyavirus, Hantaan virus, and bocavirus (boca) was analyzed by polymerase chain reaction. The DNA and amino acid sequences of tick-borne pathogens were compared for homology, and the phylogenetic trees were constructed by using Mega and Lasergene software. Results: A total of 210 ticks were collected and they belonged to three species: Dermacentor nuttalli, Ixodes persulcatus, and Haemaphysalis verticalis. Among them, 165 (78.57%) ticks tested positive for 5 pathogens, namely Ap, SFG Rk, Cb, Bl, and boca. Fifteen (7.14%) ticks were detected coinfection with two pathogens, and none were coinfected with three or more pathogens. Conclusion: This study shows the prevalence of at least five tick-borne pathogens in Argun, and there is a risk of coinfection by two pathogens in one tick. This study reveals the great importance of controlling tick-borne diseases in this region.

Near-Infrared-Driven Nanorocket for Rapid and Ultrasensitive Detection of MicroRNA.

Herein, by introducing gold nanostars (AuNSs) as fuel core, a near-infrared-driven nanorocket (NIDNR) with pretty fast walking was exploited for ultrasensitive miRNA detection. Compared with traditional nanomaterials-comprised nanomachines (NMs), the NIDNR possesses much better kinetic and thermodynamic performance owing to the extra photothermal driving force from localized surface plasmon (LSP). Impressively, the whole reaction time of NIDNR down to 15 min was realized, which is almost more than 8 times beyond those of conventional DNA-based NMs. This way, the inherent obstacle of traditional NMs, including long reaction time and low efficiency, could be easily addressed. As a proof of concept, the NIDNR was successfully applied to develop an electrochemical biosensing platform for rapid and sensitive detection of miRNA with an LOD down to 2.95 aM and achieved the real-time assay of real biological samples from human hepatocellular carcinoma cells (MHCC97L) and HeLa, thus providing an innovative insight to design more versatile DNA nanomachines for ultimate application in biosensing platform construction and clinical sample detection.

Efficient NH3-Tolerant Nickel-Based Hydrogen Oxidation Catalyst for Anion Exchange Membrane Fuel Cells.

Converting hydrogen chemical energy into electrical energy by fuel cells offers high efficiencies and environmental advantages, but ultrapure hydrogen (over 99.97%) is required; otherwise, the electrode catalysts, typically platinum on carbon (Pt/C), will be poisoned by impurity gases such as ammonia (NH3). Here we demonstrate remarkable NH3 resistivity over a nickel-molybdenum alloy (MoNi4) modulated by chromium (Cr) dopants. The resultant Cr-MoNi4 exhibits high activity toward alkaline hydrogen oxidation and can undergo 10,000 cycles without apparent activity decay in the presence of 2 ppm of NH3. Furthermore, a fuel cell assembled with this catalyst retains 95% of the initial peak power density even when NH3 (10 ppm)/H2 was fed, whereas the power output reduces to 61% of the initial value for the Pt/C catalyst. Experimental and theoretical studies reveal that the Cr modifier not only creates electron-rich states that restrain lone-pair electron donation but also downshifts the d-band center to suppress d-electron back-donation, synergistically weakening NH3 adsorption.

Self-accelerated DNA walker mediated electrochemical biosensor for rapid and ultrasensitive detection of microRNA.

Herein, we developed a novel three-dimensional (3D) self-accelerated DNA walker (SADW) which progressively expedite walking rate by unlocking the more walking arm continuously in walker process to construct electrochemical biosensor for ultrasensitive detection of microRNA. Particularly, we skillfully introduced a target analogue sequence in the double-loop hairpin, which could be released in the walking process of SADW, then rapidly activating more silenced walking strands to achieve the continuous self-acceleration, resulting in the expedited reaction rate. Surprisingly, the average reaction rate of SADW was quite higher than that of traditional 3D self-circulating DNA walkers (DW) under pretty low target miRNA concentration, which is ascribed to the outstanding acceleration process of the SADW, readily conquering the major predicaments of DW in detecting target with traces concentration: slow reaction rate and low sensitivity. This way, the elaborated SADW is favorably applied in the ultrasensitive and rapid detection of miRNA-21 in tumor cancer cell lysates with a detection limit down to 5.81 aM which was far from lower than the detection limit of DW. This approach develops the novel generation of widespread strategy for the applications in clinic diagnose, biosensing assay, and DNA nanobiotechnology.

Efficient acidic hydrogen evolution in proton exchange membrane electrolyzers over a sulfur-doped marcasite-type electrocatalyst.

Large-scale deployment of proton exchange membrane (PEM) water electrolyzers has to overcome a cost barrier resulting from the exclusive adoption of platinum group metal (PGM) catalysts. Ideally, carbon-supported platinum used at cathode should be replaced with PGM-free catalysts, but they often undergo insufficient activity and stability subjecting to corrosive acidic conditions. Inspired by marcasite existed under acidic environments in nature, we report a sulfur doping-driven structural transformation from pyrite-type cobalt diselenide to pure marcasite counterpart. The resultant catalyst drives hydrogen evolution reaction with low overpotential of 67 millivolts at 10 milliamperes per square centimeter and exhibits no degradation after 1000 hours of testing in acid. Moreover, a PEM electrolyzer with this catalyst as cathode runs stably over 410 hours at 1 ampere per square centimeter and 60°C. The marked properties arise from sulfur doping that not only triggers formation of acid-resistant marcasite structure but also tailors electronic states (e.g., work function) for improved hydrogen diffusion and electrocatalysis.

Design Principles for Maximizing Hole Utilization of Semiconductor Quantum Wires toward Efficient Photocatalysis.

Maximizing hole-transfer kinetics-usually a rate-determining step in semiconductor-based artificial photosynthesis-is pivotal for simultaneously enabling high-efficiency solar hydrogen production and hole utilization. However, this remains elusive yet as efforts are largely focused on optimizing the electron-involved half-reactions only by empirically employing sacrificial electron donors (SEDs) to consume the wasted holes. Using high-quality ZnSe quantum wires as models, we show that how hole-transfer processes in different SEDs affect their photocatalytic performances. We found that larger driving forces of SEDs monotonically enhance hole-transfer rates and photocatalytic performances by almost three orders of magnitude, a result conforming well with the Auger-assisted hole-transfer model in quantum-confined systems. Intriguingly, further loading Pt cocatalyts can yield either an Auger-assisted model or a Marcus inverted region for electron transfer, depending on the competing hole-transfer kinetics in SEDs.

Highly Enhanced Chloride Adsorption Mediates Efficient Neutral CO2 Electroreduction over a Dual-Phase Copper Catalyst.

Electrocatalytic carbon dioxide reduction (CO2R) in neutral electrolytes can mitigate the energy and carbon losses caused by carbonate formation but often experiences unsatisfied multicarbon selectivity and reaction rates because of the kinetic limitation to the critical carbon monoxide (CO)-CO coupling step. Here, we describe that a dual-phase copper-based catalyst with abundant Cu(I) sites at the amorphous-nanocrystalline interfaces, which is electrochemically robust in reducing environments, can enhance chloride-specific adsorption and consequently mediate local *CO coverage for improved CO-CO coupling kinetics. Using this catalyst design strategy, we demonstrate efficient multicarbon production from CO2R in a neutral potassium chloride electrolyte (pH ∼6.6) with a high Faradaic efficiency of 81% and a partial current density of 322 milliamperes per square centimeter. This catalyst is stable after 45 h of operation at current densities relevant to commercial CO2 electrolysis (300 mA per square centimeter).

Spatial and temporal variations of extreme climate index in the Songhua River Basin during 1961-2020.

Understanding climate change and extreme climate is of great significance for ensuring food security and socio-economic development of the Songhua River Basin. Based on the daily precipitation, maximum temperature and minimum temperature data during 1961-2020 from 69 meteorological stations in and around the Songhua River Basin, we analyzed the temporal and spatial variations of extreme temperature and precipitation in the Songhua River Basin using 27 extreme climate indices recommended by the World Meteorological Organization, and linear trend method, Mann-Kendall trend test and ordinary Kriging interpolation methodology. The results showed that, from 1961 to 2020, except for cold speel duration, the extreme cold index in the study area showed a downward trend, while the extreme warm index, extreme value index and other temperature indices showed an upward trend. The increasing trend of the minimum temperature was greater than that of the maximum temperature. Icing days, cold speel duration and warm speel duration showed an increasing trend from south to north, while the minimum value of maximum temperature and that of minimum temperature showed opposite spatial characteristics. The high value areas of summer days and tropical nights were mainly distributed in the southwestern region, while there was no obvious spatial variations of cool days, warm nights, and warm days. Overall, except for cold speel duration, other extreme cold indices had a rapid decreasing trend in the north and west of the Songhua River Basin. In the warm index, summer days, warm nights, warm days, and warm speel duration had a rapid upward trend in the north and west, and tropical nights had the fastest rise in the southwest. In the extreme value index, the maximum of temperature rose fastest in the northwest, while the minimum rose fastest in the northeast. Except for consecutive dry days, the rest of precipitation indices showed an increasing trend, and the fastest rising areas were mainly in the north-central part of the Nenjiang River Basin, while some areas in the south of the Nenjiang River Basin became dry. Heavy precipitation days, very heavy precipitation days, heaviest precipitation days, consecutive wet days, very wet day precipitation, extremely wet day precipitation, and annual precipitation showed a gradual decreasing pattern from southeast to northwest. Overall, the Songhua River Basin was warming and wetting, but there were some differences among different regions, especially the northern and southern parts of the Nenjiang River Basin.

Simultaneous Determination of Rifamycin Antibiotics and Their Active Metabolites in Human Plasma Using UHPLC-MS/MS to Evaluate Their Impact on Target Peak Concentrations: A Short Communication.

BACKGROUND: Standard and proper antituberculosis (anti-TB) treatment is essential for patients with TB, and rifamycin antibiotics are key components of anti-TB therapy. Therapeutic drug monitoring (TDM) of rifamycin antibiotics can shorten the time to response and complete treatment of TB. Notably, antimicrobial activities of the major active metabolites of rifamycin are similar to those of their parent compounds. Thus, a rapid and simple assay was developed for simultaneous determination of rifamycin antibiotics and their major active metabolites in plasma to evaluate their impact on target peak concentrations. Here, the authors have developed and validated a method for simultaneous determination of rifamycin antibiotics and their active metabolites in human plasma using ultrahigh-performance liquid chromatography tandem mass spectrometry. METHODS: Analytical validation of the assay was performed in accordance with the bioanalytical method validation guidance for industry described by the US Food and Drug Administration and the guidelines for bioanalytical method validation described by the European Medicines Agency. RESULTS: The drug concentration quantification method for rifamycin antibiotics, including rifampicin, rifabutin, and rifapentine, and their major active metabolites was validated. Significant differences in the proportions of active metabolites in rifamycin antibiotics may affect the redefinition of their effective concentration ranges in the plasma. The method developed herein is expected to redefine the ranges of "true" effective concentrations of rifamycin antibiotics (including parent compounds and their active metabolites). CONCLUSIONS: The validated method can be successfully applied for high-throughput analysis of rifamycin antibiotics and their active metabolites for TDM in patients receiving anti-TB treatment regimens containing these antibiotics. Proportions of active metabolites in rifamycin antibiotics markedly varied among individuals. Depending on the clinical indications of patients, the therapeutic ranges for rifamycin antibiotics may be redefined.