Urinary dengue NS1 detection on Au-decorated ZnO nanowire platform

Biodetection for non-invasive diagnostics of fluids, especially urine, remains a challenge to scientists due to low target concentrations. And biological complexes of the detection target may contain contaminants that also interfere with any assay. Dengue non-structural 1 protein (Dengue NS1) is an important biomarker for dengue hemorrhagic fever and dengue shock syndrome. Here, we developed an Au-decorated nanowire platform and applied it with a sandwich fluorophore-linked immunosorbent well plate assay (FLISA) to detect Dengue NS1 in urine. For the platform, we fabricated zinc oxide (ZnO) nanowires to provide a high surface area and then coated them with gold nanoparticles (ZnO/Au nanowires) to simply modify the Dengue NS1 antibody and enhance the fluorescence intensity. Our platform employs a sandwich FLISA that exhibits high sensitivity, specifically detecting Dengue NS1 with a limit of detection (LOD) of 1.35 pg/mL. This LOD was 4500-fold lower than the LOD of a commercially available kit for Dengue NS1 enzyme-linked immunosorbent assay. We believe that our ZnO/Au nanowire platform has the potential to revolutionize the field of non-invasive diagnostics for dengue.

Resistive Pulse Sensing on a Capillary-Assisted Microfluidic Platform for On-Site Single-Particle Analyses

Capillary-assisted flow is valuable for utilizing microfluidics-based electrical sensing platforms at on-site locations by simplifying microfluidic operations and system construction; however, incorporating capillary-assisted flow in platforms requires easy microfluidic modification and stability over time for capillary-assisted flow generation and sensing performance. Herein, we report a capillary-assisted microfluidics-based electrical sensing platform using a one-step modification of polydimethylsiloxane (PDMS) with polyethylene glycol (PEG). As a model of electrical sensing platforms, this work focused on resistive pulse sensing (RPS) using a micropore in a microfluidic chip for label-free electrical detection of single analytes, and filling the micropore with an electrolyte is the first step to perform this RPS. The PEG-PDMS surfaces remained hydrophilic after ambient storage for 30 d and assisted in generating an electrolyte flow for filling the micropore with the electrolyte. We demonstrated the successful detection and size analysis of micrometer particles and bacterial cells based on RPS using the microfluidic chip stored in a dry state for 30 d. Combining this capillary-assisted microfluidic platform with a portable RPS system makes on-site detection and analysis of single pathogens possible.

Spatial exosome analysis using cellulose nanofiber sheets reveals the location heterogeneity of extracellular vesicles

Extracellular vesicles (EVs), including exosomes, are recognized as promising functional targets involved in disease mechanisms. However, the intravital heterogeneity of EVs remains unclear, and the general limitation for analyzing EVs is the need for a certain volume of biofluids. Here, we present cellulose nanofiber (CNF) sheets to resolve these issues. We show that CNF sheets capture and preserve EVs from ~10 μL of biofluid and enable the analysis of bioactive molecules inside EVs. By attaching CNF sheets to moistened organs, we collect EVs in trace amounts of ascites, which is sufficient to perform small RNA sequence analyses. In an ovarian cancer mouse model, we demonstrate that CNF sheets enable the detection of cancer-associated miRNAs from the very early phase when mice did not have apparent ascites, and that EVs from different locations have unique miRNA profiles. By performing CNF sheet analyses in patients, we identify further location-based differences in EV miRNA profiles, with profiles reflecting disease conditions. We conduct spatial exosome analyses using CNF sheets to reveal that ascites EVs from cancer patients exhibit location-dependent heterogeneity. This technique could provide insights into EV biology and suggests a clinical strategy contributing to cancer diagnosis, staging evaluation, and therapy planning.

Metal Oxide Nanostructures Enhanced Microfluidic Platform for Efficient and Sensitive Immunofluorescence Detection of Dengue Virus

Rapid and sensitive detection of Dengue virus remains a critical challenge in global public health. This study presents the development and evaluation of a Zinc Oxide nanorod (ZnO NR)-surface-integrated microfluidic platform for the early detection of Dengue virus. Utilizing a seed-assisted hydrothermal synthesis method, high-purity ZnO NRs were synthesized, characterized by their hexagonal wurtzite structure and a high surface-to-volume ratio, offering abundant binding sites for bioconjugation. Further, a comparative analysis demonstrated that the ZnO NR substrate outperformed traditional bare glass substrates in functionalization efficiency with 4G2 monoclonal antibody (mAb). Subsequent optimization of the functionalization process identified 4% (3-Glycidyloxypropyl)trimethoxysilane (GPTMS) as the most effective surface modifier. The integration of this substrate within a herringbone-structured microfluidic platform resulted in a robust device for immunofluorescence detection of DENV-3. The limit of detection (LOD) for DENV-3 was observed to be as low as 3.1 × 10-4 ng/mL, highlighting the remarkable sensitivity of the ZnO NR-integrated microfluidic device. This study emphasizes the potential of ZnO NRs and the developed microfluidic platform for the early detection of DENV-3, with possible expansion to other biological targets, hence paving the way for enhanced public health responses and improved disease management strategies.

Impact of menopausal symptoms on presenteeism in Japanese women

BACKGROUND

Menopausal symptoms are common among middle-aged women. Working women with severe menopausal symptoms are more likely to experience presenteeism-a condition where employees continue to work despite feeling unwell. However, it remains unclear as to which specific symptoms women experience during the menopausal transition and postmenopausal periods that primarily contribute to presenteeism.

AIMS

To evaluate the associations between types of menopausal symptoms and presenteeism among Japanese women.

METHODS

A cross-sectional study of 4000 women aged 40-59 years who were currently working was conducted in Japan in September 2022. We used an online self-administered questionnaire that included items on demographic characteristics, the Menopause Rating Scale for measuring menopausal symptoms and the Work Functioning Impairment Scale for measuring presenteeism. Logistic regression analysis was performed.

RESULTS

Women with severe overall menopausal symptoms had 12.18-fold (95% confidence interval [CI] 9.09-16.33, P < 0.001) increased odds of presenteeism compared with those without symptoms. Participants with psychological symptoms also had significantly higher presenteeism (severe: odds ratio: 9.18, 95% CI 6.60-12.78, P < 0.001). However, after controlling for psychological symptoms, there were no significant associations between somatic and urogenital symptoms and presenteeism.

CONCLUSIONS

The results indicate that menopausal symptoms, especially psychological symptoms, have a significant impact on presenteeism among Japanese women. Organizations need to address menopausal symptoms in the workplace, with an emphasis on reducing work-related stress for women with menopausal symptoms.

Effects of Radiation Doses on Clinical Recurrence in Patients with Biochemically Recurrent Prostate Cancer after Prostatectomy

PURPOSE/OBJECTIVE(S)

Salvage radiotherapy (SRT) to the prostate bed is the only curative treatment for patients with biochemical recurrence (BCR) after radical prostatectomy (RP). Although several systematic reviews indicated that a dose escalation in the range of 60-70 Gy improved biochemical control, the effects of radiation doses on clinical relapse after SRT remain unclear. Our aim was to investigate the relationship between radiation doses and clinical relapse-free survival (cRFS) after SRT.

MATERIALS/METHODS

We identified 295 eligible patients receiving SRT for biochemically recurrent prostate cancer after RP between 2005 and 2018 at 15 institutions. Sixteen patients (5%) received short-term (< 6 months) androgen deprivation therapy (ADT) following RP and/or concurrently with SRT. SRT was delivered to the prostate and seminal vesicle bed using photon beams at a median (range) dose of 66 Gy (61-85) in 1.8-3.0 Gy fractions. The primary outcome was cRFS. Clinical relapse was identified on radiological imaging and/or biopsy and included local recurrence, lymph node metastasis, and distant metastasis. In all analyses, doses were recalculated as an equivalent dose in 2-Gy fractions (EQD2) with α/β = 1.5 Gy. Clinical RFS between the EQD2 ≥ 66 Gy (n = 229) and EQD2 < 66 Gy (n = 66) groups were compared using the Log-rank test, followed by univariate and multivariate Cox regression analyses and a subgroup analysis.

RESULTS

The median follow-up duration was 73 months. Among patients with BCR (n = 119), 79 of 96 (82%) in the EQD2 ≥ 66 Gy group and 21 of 23 (91%) in the EQD2 < 66 Gy group received second salvage ADT (p = 0.36). Among all patients (n = 295), clinical relapse was identified in 22 (7%) patients after SRT. Six-year biochemical relapse-free survival (bRFS), cRFS, cancer-specific survival (CSS), and overall survival (OS) rates were 58%, 93%, 98%, and 94%, respectively. Six-year cRFS rates were 94% (95% confidence interval [CI], 90-97) in the EQD2 ≥ 66 Gy group and 87% (95% CI, 75-93) in the EQD2 < 66 Gy group (p = 0.020). The multivariate analysis revealed that EQD2 < 66 Gy, Gleason score ≥ 8, seminal vesicle involvement, and PSA at BCR ≥ 0.5 ng/ml correlated with clinical relapse (p = 0.0016, 0.014, 0.011, and 0.027, respectively). The subgroup analysis showed the consistent benefit of EQD2 ≥ 66 Gy in patients across most subgroups including PSA at BCR after RP, extracapsular extension, and age at SRT.

CONCLUSION

This large multi-institutional observational study demonstrated that a higher SRT dose (EQD2 ≥ 66 Gy) resulted in superior cRFS. The present result supports the dose recommendations in the 2023 National Comprehensive Cancer Network guidelines (64-72 Gy) even in terms of clinical relapse. Prospective trial is warranted to investigate an upper threshold for optimal SRT dose.

Engineering Interface Defects and Interdiffusion at the Degenerate Conductive In2O3/Al2O3 Interface for Stable Electrodes in a Saline Solution

A low-temperature Al₂O₃ deposition process provides a simplified method to form a conductive two-dimensional electron gas (2DEG) at the metal oxide/Al₂O₃ heterointerface. However, the impact of key factors of the interface defects and cation interdiffusion on the interface is still not well understood. Furthermore, there is still a blank space in terms of applications that go beyond the understanding of the interface's electrical conductivity. In this work, we carried out a systematic experimental study by oxygen plasma pretreatment and thermal annealing post-treatment to study the impact of interface defects and cation interdiffusion at the In₂O₃/Al₂O₃ interface on the electrical conductance, respectively. Combining the trends in electrical conductance with the structural characteristics, we found that building a sharp interface with a high concentration of interface defects provides a reliable approach to producing such a conductive interface. After applying this conductive interface as electrodes for fabricating a field-effect transistor (FET) device, we found that this interface electrode exhibited ultrastability in phosphate-buffered saline (PBS), a commonly used biological saline solution. This study provides new insights into the formation of conductive 2DEGs at metal oxide/Al₂O₃ interfaces and lays the foundation for further applications as electrodes in bioelectronic devices.

Identifying high-grade serous ovarian carcinoma-specific extracellular vesicles by polyketone-coated nanowires

Cancer cell-derived extracellular vesicles (EVs) have unique protein profiles, making them promising targets as disease biomarkers. High-grade serous ovarian carcinoma (HGSOC) is the deadly subtype of epithelial ovarian cancer, and we aimed to identify HGSOC-specific membrane proteins. Small EVs (sEVs) and medium/large EVs (m/lEVs) from cell lines or patient serum and ascites were analyzed by LC-MS/MS, revealing that both EV subtypes had unique proteomic characteristics. Multivalidation steps identified FRα, Claudin-3, and TACSTD2 as HGSOC-specific sEV proteins, but m/lEV-associated candidates were not identified. In addition, for using a simple-to-use microfluidic device for EV isolation, polyketone-coated nanowires (pNWs) were developed, which efficiently purify sEVs from biofluids. Multiplexed array assays of sEVs isolated by pNW showed specific detectability in cancer patients and predicted clinical status. In summary, the HGSOC-specific marker detection by pNW are a promising platform as clinical biomarkers, and these insights provide detailed proteomic aspects of diverse EVs in HGSOC patients.

Mutation detection of urinary cell-free DNA via catch-and-release isolation on nanowires for liquid biopsy

Cell-free DNA (cfDNA) and extracellular vesicles (EVs) are molecular biomarkers in liquid biopsies that can be applied for cancer detection, which are known to carry information on the necessary conditions for oncogenesis and cancer cell-specific activities after oncogenesis, respectively. Analyses for both cfDNA and EVs from the same body fluid can provide insights into screening and identifying the molecular subtypes of cancer; however, a major bottleneck is the lack of efficient and standardized techniques for the isolation of cfDNA and EVs from clinical specimens. Here, we achieved catch-and-release isolation by hydrogen bond-mediated binding of cfDNA in urine to zinc oxide (ZnO) nanowires, which also capture EVs by surface charge, and subsequently we identified genetic mutations in urinary cfDNA. The binding strength of hydrogen bonds between single-crystal ZnO nanowires and DNA was found to be equal to or larger than that of conventional hydrophobic interactions, suggesting the possibility of isolating trace amounts of cfDNA. Our results demonstrated that nanowire-based cancer screening assay can screen cancer and can identify the molecular subtypes of cancer in urine from brain tumor patients through EV analysis and cfDNA mutation analysis. We anticipate our method to be a starting point for more sophisticated diagnostic models of cancer screening and identification.

All-in-One Nanowire Assay System for Capture and Analysis of Extracellular Vesicles from an ex Vivo Brain Tumor Model

Extracellular vesicles (EVs) have promising potential as biomarkers for early cancer diagnosis. The EVs have been widely studied as biological cargo containing essential biological information not only from inside vesicles such as nucleic acids and proteins but also from outside vesicles such as membrane proteins and glycolipids. Although various methods have been developed to isolate EVs with high yields such as captures based on density, size, and immunoaffinity, different measurement systems are needed to analyze EVs after isolation, and a platform that enables all-in-one analysis of EVs from capture to detection in multiple samples is desired. Since a nanowire-based approach has shown an effective capability for capturing EVs via surface charge interaction compared to other conventional methods, here, we upgraded the conventional well plate assay to an all-in-one nanowire-integrated well plate assay system (i.e., a nanowire assay system) that enables charge-based EV capture and EV analysis of membrane proteins. We applied the nanowire assay system to analyze EVs from brain tumor organoids in which tumor environments, including vascular formations, were reconstructed, and we found that the membrane protein expression ratio of CD31/CD63 was 1.42-fold higher in the tumor organoid-derived EVs with a p-value less than 0.05. Furthermore, this ratio for urine samples from glioblastoma patients was 2.25-fold higher than that from noncancer subjects with a p-value less than 0.05 as well. Our results demonstrated that the conventional well plate method integrated with the nanowire-based EV capture approach allows users not only to capture EVs effectively but also to analyze them in one assay system. We anticipate that the all-in-one nanowire assay system will be a powerful tool for elucidating EV-mediated tumor-microenvironment crosstalk.

Non-competitive fluorescence polarization immunosensing for CD9 detection using a peptide as a tracer

This paper is the first report of a non-competitive fluorescence polarization immunoassay (NC-FPIA) using a peptide as a tracer. The NC-FPIA can easily and quickly quantify the target after simply mixing them together. This feature is desirable for point-of-need applications such as clinical diagnostics, infectious disease screening, on-site analysis for food safety, etc. In this study, the NC-FPIA was applied to detect CD9, which is one of the exosome markers. We succeeded in detecting not only CD9 but also CD9 expressing exosomes derived from HeLa cells. This method can be applied to various targets if a tracer for the target can be prepared, and expectations are high for its future uses.

Correction: Breath odor-based individual authentication by an artificial olfactory sensor system and machine learning

Correction for 'Breath odor-based individual authentication by an artificial olfactory sensor system and machine learning' by Chaiyanut Jirayupat et al., Chem. Commun., 2022, DOI: https://doi.org/10.1039/D1CC06384G.

Tailoring ZnO nanowire crystallinity and morphology for label-free capturing of extracellular vesicles

Zinc oxide (ZnO) nanowires have shown their potential in isolation of cancer-related biomolecules such as extracellular vesicles (EVs), RNAs, and DNAs for early diagnosis and therapeutic development of diseases. Since the function of inorganic nanowires changes depending on their morphology, previous studies have established strategies to control the morphology and have demonstrated attainment of improved properties for gas and organic compound detection, and for dye-sensitized solar cells and photoelectric conversion performance. Nevertheless, crystallinity and morphology of ZnO nanowires for capturing EVs, an important biomarker of cancer, have not yet been discussed. Here, we fabricated ZnO nanowires with different crystallinities and morphologies using an ammonia-assisted hydrothermal method, and we comprehensively analyzed the crystalline nature and oriented growth of the synthesized nanowires by X-ray diffraction and selected area electron diffraction using high resolution transmission electron microscopy. In evaluating the performance of label-free EV capture in a microfluidic device platform, we found both the crystallinity and morphology of ZnO nanowires affected EV capture efficiency. In particular, the zinc blende phase was identified as important for crystallinity, while increasing the nanowire density in the array was important for morphology to improve EV capture performance. These results highlighted that the key physicochemical properties of the ZnO nanowires were related to the EV capture performance.

Water-Selective Nanostructured Dehumidifiers for Molecular Sensing Spaces

Humidity and moisture effects, frequently called water poisoning, in surroundings are inevitable for various molecular sensing devices, strongly affecting their sensing characteristics. Here, we demonstrate a water-selective nanostructured dehumidifier composed of ZnO/TiO₂/CaCl₂ core-shell heterostructured nanowires for molecular sensing spaces. The fabricated nanostructured dehumidifier is highly water-selective without detrimental adsorptions of various volatile organic compound molecules and can be repeatedly operated. The thermally controllable and reversible dehydration process of CaCl₂·nH₂O thin nanolayers on hydrophilic ZnO/TiO₂ nanowire surfaces plays a vital role in such water-selective and repeatable dehumidifying operations. Furthermore, the limitation of detection for sensing acetone and nonanal molecules in the presence of moisture (relative humidity ∼ 90%) was improved more than 20 times using nanocomposite sensors by operating the developed nanostructured dehumidifier. Thus, the proposed water-selective nanostructured dehumidifier offers a rational strategy and platform to overcome water poisoning issues for various molecular and gas sensors.

Breath odor-based individual authentication by an artificial olfactory sensor system and machine learning

The potential feasibility of breath odor sensing-based individual authentication was demonstrated by a 16-channel chemiresistive sensor array and machine learning.

Oxide nanowire microfluidics addressing previously-unattainable analytical methods for biomolecules towards liquid biopsy

Nanowire microfluidics using a combination of self-assembly and nanofabrication technologies is expected to be applied to various fields due to its unique properties. We have been working on the fabrication of nanowire microfluidic devices and the development of analytical methods for biomolecules using the unique phenomena generated by the devices. The results of our research are not just limited to the development of nanospace control with "targeted dimensions" in "targeted arrangements" with "targeted materials/surfaces" in "targeted spatial locations/structures" in microfluidic channels, but also cover a wide range of analytical methods for biomolecules (extraction, separation/isolation, and detection) that are impossible to achieve with conventional technologies. Specifically, we are working on the extraction technology "the cancer-related microRNA extraction method in urine," the separation technology "the ultrafast and non-equilibrium separation method for biomolecules," and the detection technology "the highly sensitive electrical measurement method." These research studies are not just limited to the development of biomolecule analysis technology using nanotechnology, but are also opening up a new academic field in analytical chemistry that may lead to the discovery of new pretreatment, separation, and detection principles.

Abstract 2604: Urinary microRNAs as biomarkers for early detection of urothelial cancer

microRNAs modulate gene expression in various cancer types, and their profiles differ in healthy and cancer groups of people and they represent a warning sign for various cancer scenarios. Identification of tumor-specific microRNAs presents a powerful opportunity to potentially reduce cancer mortality through early detection. In order to achieve early detection through population screening, noninvasive approaches are needed to complement and improve upon current strategies for urothelial cancer (UC) screening. Since all microRNAs in the blood cannot be transferred from donor to recipient cells during single blood circulation, kidney filtration could pass some untransferred microRNAs from blood to urine, therefore urinary microRNAs might be used as biomarkers for the diagnosis of cancer. We investigated whether urine levels of microRNA can differentiate patients with UC from healthy individuals. Here, we successfully identified UC-related microRNA ensembles in urine through a combination of microfluidic microRNA extraction device and machine learning-based analysis.

We analyzed 93 urine samples from 27 UC patients and 66 healthy individuals (controls). An initial set of 74 microRNAs was selected by microarray microRNA profiling assay as biomarker candidates. Quantitative reverse-transcription PCR was used for further analysis to validate the expression of microRNAs.

We selected a group of 6 microRNAs for validation; (miR-6089, miR-4488, miR-4784, miR-26a-5p, miR-148a-3p, and miR-143-3p) were confirmed to be significantly different in UC and controls. We adopted a logistic regression model and successfully developed a classifier based on these 6 microRNAs, which showed remarkably high sensitivity (94%) and specificity (85%).

In summary, patients with UC have significantly different patterns of microRNA expression from healthy individuals. We identified a signature of 6 microRNAs as predictors that can differentiate patients with UC from those who are healthy. These microRNAs could be potentially developed as biomarkers for UC.

Citation Format: Kazuya Takayama, Kohei Yamazaki, Hiroki Yamaguchi, Keishu Tsuda, Takao Yasui, Yuki Ichikawa. Urinary microRNAs as biomarkers for early detection of urothelial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2604.

Rapid Discrimination of Extracellular Vesicles by Shape Distribution Analysis

A rapid and simple cancer detection method independent of cancer type is an important technology for cancer diagnosis. Although the expression profiles of biological molecules contained in cancer cell-derived extracellular vesicles (EVs) are considered candidates for discrimination indexes to identify any cancerous cells in the body, it takes a certain amount of time to examine these expression profiles. Here, we report the shape distributions of EVs suspended in a solution and the potential of these distributions as a discrimination index to discriminate cancer cells. Distribution analysis is achieved by low-aspect-ratio nanopore devices that enable us to rapidly analyze EV shapes individually in solution, and the present results reveal a dependence of EV shape distribution on the type of cells (cultured liver, breast, and colorectal cancer cells and cultured normal breast cells) secreting EVs. The findings in this study provide realizability and experimental basis for a simple method to discriminate several types of cancerous cells based on rapid analyses of EV shape distributions.

Urinary MicroRNA-Based Diagnostic Model for Central Nervous System Tumors Using Nanowire Scaffolds

There are no accurate mass screening methods for early detection of central nervous system (CNS) tumors. Recently, liquid biopsy has received a lot of attention for less-invasive cancer screening. Unlike other cancers, CNS tumors require efforts to find biomarkers due to the blood-brain barrier, which restricts molecular exchange between the parenchyma and blood. Additionally, because a satisfactory way to collect urinary biomarkers is lacking, urine-based liquid biopsy has not been fully investigated despite the fact that it has some advantages compared to blood or cerebrospinal fluid-based biopsy. Here, we have developed a mass-producible and sterilizable nanowire-based device that can extract urinary microRNAs efficiently. Urinary microRNAs from patients with CNS tumors (n = 119) and noncancer individuals (n = 100) were analyzed using a microarray to yield comprehensive microRNA expression profiles. To clarify the origin of urinary microRNAs of patients with CNS tumors, glioblastoma organoids were generated. Glioblastoma organoid-derived differentially expressed microRNAs (DEMs) included 73.4% of the DEMs in urine of patients with parental tumors but included only 3.9% of those in urine of noncancer individuals, which suggested that many CNS tumor-derived microRNAs could be identified in urine directly. We constructed the diagnostic model based on the expression of the selected microRNAs and found that it was able to differentiate patients and noncancer individuals at a sensitivity and specificity of 100 and 97%, respectively, in an independent dataset. Our findings demonstrate that urinary microRNAs extracted with the nanowire device offer a well-fitted strategy for mass screening of CNS tumors.

Rational Strategy for Space-Confined Seeded Growth of ZnO Nanowires in Meter-Long Microtubes

Seeded crystal growths of nanostructures within confined spaces offer an interesting approach to design chemical reaction spaces with tailored inner surface properties. However, such crystal growth within confined spaces tends to be inherently difficult as the length increases as a result of confinement effects. Here, we demonstrate a space-confined seeded growth of ZnO nanowires within meter-long microtubes of 100 μm inner diameter with the aspect ratio of up to 10 000, which had been unattainable to previous methods of seeded crystal growths. ZnO nanowires could be grown via seeded hydrothermal crystal growth for relatively short microtubes below the length of 40 mm, while any ZnO nanostructures were not observable at all for longer microtubes above 60 mm with the aspect ratio of 600. Microstructural and mass spectrometric analysis revealed that a conventional seed layer formation using zinc acetate is unfeasible within the confined space of long microtubes as a result of the formation of detrimental residual Zn complex compounds. To overcome this space-confined issue, a flow-assisted seed layer formation is proposed. This flow-assisted method enables growth of spatially uniform ZnO nanowires via removing residual compounds even for 1 m long microtubes with the aspect ratio of up to 10 000. Finally, the applicably of ZnO-nanowire-decorated long microtubes for liquid-phase separations was demonstrated.

Microheater-integrated zinc oxide nanowire microfluidic device for hybridization-based detection of target single-stranded DNA

Detection of cell-free DNA (cfDNA) has an impact on DNA analysis in liquid biopsies. However, current strategies to detect cfDNA have limitations that should be overcome, such as having low sensitivity and requiring much time and a specialized instrument. Thus, non-invasive and rapid detection tools are needed for disease prevention and early-stage treatment. Here we developed a device having a microheater integrated with zinc oxide nanowires (microheater-ZnO-NWs) to detect target single-stranded DNAs (ssDNAs) based on DNA probe hybridization. We confirmed experimentally that our device realizedin-situannealed DNA probes by which we subsequently detected target ssDNAs. We envision that this device can be utilized for fundamental studies related to nanobiodevice-based DNA detection.

The impact of surface Cu2+ of ZnO/(Cu1-x Zn x )O heterostructured nanowires on the adsorption and chemical transformation of carbonyl compounds

The surface cation composition of nanoscale metal oxides critically determines the properties of various functional chemical processes including inhomogeneous catalysts and molecular sensors. Here we employ a gradual modulation of cation composition on a ZnO/(Cu1-x Zn x )O heterostructured nanowire surface to study the effect of surface cation composition (Cu/Zn) on the adsorption and chemical transformation behaviors of volatile carbonyl compounds (nonanal: biomarker). Controlling cation diffusion at the ZnO(core)/CuO(shell) nanowire interface allows us to continuously manipulate the surface Cu/Zn ratio of ZnO/(Cu1-x Zn x )O heterostructured nanowires, while keeping the nanowire morphology. We found that surface exposed copper significantly suppresses the adsorption of nonanal, which is not consistent with our initial expectation since the Lewis acidity of Cu2+ is strong enough and comparable to that of Zn2+. In addition, an increase of the Cu/Zn ratio on the nanowire surface suppresses the aldol condensation reaction of nonanal. Surface spectroscopic analysis and theoretical simulations reveal that the nonanal molecules adsorbed at surface Cu2+ sites are not activated, and a coordination-saturated in-plane square geometry of surface Cu2+ is responsible for the observed weak molecular adsorption behaviors. This inactive surface Cu2+ well explains the mechanism of suppressed surface aldol condensation reactions by preventing the neighboring of activated nonanal molecules. We apply this tailored cation composition surface for electrical molecular sensing of nonanal and successfully demonstrate the improvements of durability and recovery time as a consequence of controlled surface molecular behaviors.

Microfluidic-based capture and release of cancer-derived exosomes via peptide-nanowire hybrid interface

Cancer-derived circulating exosomes or nanoscale extracellular vesicles are emerging biomarkers for disease detection and treatment because of their cell-specific constituents and unique intercellular pathways. For efficient exosome isolation from bio-fluids, the design of high-affinity nanointerfaces is of great importance in the development of miniaturized systems for the collection of exosomes. Herein, we report peptide-functionalized nanowires as a biorecognition interface for the capture and release of cancer-derived exosomes within a microfluidic channel. Based on the amino-acid sequence of EWI-2 protein, a partial peptide that bound to the CD9 exosome marker and thus targeted cancer exosomes was screened. Linkage of the exosome-targeting peptide with a ZnO-binding sequence allowed one-step and reagent-free peptide modification of the ZnO nanowire array. As a result of peptide functionalization, the exosome-capturing ability of ZnO nanowires was significantly improved. Furthermore, the captured exosomes could be subsequently released from the nanowires under a neutral salt condition for downstream applications. This engineered surface that enhances the nanowires' efficiency in selective and controllable collection of cancer-derived exosomes provides an alternative foundation for developing microfluidic platforms for exosome-based diagnostics and therapeutics.

ZnO/SiO2 core/shell nanowires for capturing CpG rich single-stranded DNAs

Atomic layer deposition (ALD) is capable of providing an ultrathin layer on high-aspect ratio structures with good conformality and tunable film properties. In this research, we modified the surface of ZnO nanowires through ALD for the fabrication of a ZnO/SiO2 (core/shell) nanowire microfluidic device which we utilized for the capture of CpG-rich single-stranded DNAs (ssDNA). Structural changes of the nanowires while varying the number of ALD cycles were evaluated by statistical analysis and their relationship with the capture efficiency was investigated. We hypothesized that finding the optimum number of ALD cycles would be crucial to ensure adequate coating for successful tuning to the desired surface properties, besides promoting a sufficient trapping region with optimal spacing size for capturing the ssDNAs as the biomolecules traverse through the dispersed nanowires. Using the optimal condition, we achieved high capture efficiency of ssDNAs (86.7%) which showed good potential to be further extended for the analysis of CpG sites in cancer-related genes. This finding is beneficial to the future design of core/shell nanowires for capturing ssDNAs in biomedical applications.

Oxide Nanowire Microfluidic Devices for Capturing Single-stranded DNAs

Since DNA analysis is the fundamental process for most applications in biomedical fields, capturing DNAs with high efficiency is important. Here, we used several oxide nanowire microfluidic devices to capture CpG-rich single-stranded DNAs (ssDNAs) in different pH solutions. All the oxide nanowires exhibited the highest capture efficiency around pH 7 with good capture efficiency shown by each metal oxide; ZnO/ZnO core/shell NWs (71.6%), ZnO/Al₂O₃ core/shell NWs (86.3%) and ZnO/SiO₂ core/shell NWs (86.7%). ZnO/Al₂O₃ core/shell NWs showed the best performance for capturing ssDNAs under varying pH, which suggests its suitability for application in diverse biological fluids. The capturing efficiencies were attributed to the interactions from phosphate backbones and nucleobases of ssDNAs to each nanowire surface. This finding provides a useful platform for highly efficient capture of the target ssDNAs, and these results can be extended for future studies of cancer-related genes in complex biological fluids.

Full-field fluorescence lifetime dual-comb microscopy using spectral mapping and frequency multiplexing of dual-comb optical beats

Fluorescence lifetime imaging microscopy (FLIM) is a powerful tool for quantitative fluorescence imaging because fluorescence lifetime is independent of concentration of fluorescent molecules or excitation/detection efficiency and is robust to photobleaching. However, since most FLIMs are based on point-to-point measurements, mechanical scanning of a focal spot is needed for forming an image, which hampers rapid imaging. Here, we demonstrate scan-less full-field FLIM based on a one-to-one correspondence between two-dimensional (2D) image pixels and frequency-multiplexed radio frequency (RF) signals. A vast number of dual-comb optical beats between dual optical frequency combs are effectively adopted for 2D spectral mapping and high-density frequency multiplexing in the RF region. Bimodal images of fluorescence amplitude and lifetime are obtained with high quantitativeness from amplitude and phase spectra of fluorescence RF comb modes without the need for mechanical scanning. The parallelized FLIM will be useful for rapid quantitative fluorescence imaging in life science.

Pathological assessment of osimertinib-associated cardiotoxicity in EGFR-mutated non-small cell lung cancer patients

Background

Osimertinib, a third-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI), inhibits both EGFR-TKI sensitizing mutations and resistant T790M mutations detected in non-small cell lung cancer (NSCLC) patients. Cardiac adverse events (AEs) induced by osimertinib are infrequent; however, cases of severe associated cardiac dysfunction have been reported and remain poorly understood.

Purpose

To assess pathogenesis of osimertinib-associated cardiac AEs, we analyzed myocardial specimens of three NSCLC cases with osimertinib-associated cardiac dysfunction.

Results

Analysis of LVEF prior to and after osimertinb administration in 36 NSCLC patients showed significant decrease of LVEF from 69% to 63%. Within this cohort, right ventricular (RV) biopsy was performed in 2 cases to further understand the pathophysiology of cardiac dysfunction. Case 1 was 78-year-old female with advanced NSCLC harboring an EGFR L858R mutation was treated with osimertinib as second line therapy. After 3 moths of osimetinib treatment, she presented with dyspnea, high NT-proBNP and troponin I, and significantly decreased left ventricular ejection fraction (LVEF) at 28%. RV biopsy showed moderate cardiomyocyte hypertrophy without inflammatory cell infiltration. Case 2 was 52-year-old female with advanced NSCLC harboring L858R mutation. She was treated with osimertinib as first line therapy. After 2 weeks of osimertinib, screening echocardiography revealed a reduction of LVEF from 63% to 41% without cardiac symptom. RV biopsy showed mild cardiomyocyte hypertrophy with infiltration of a few inflammatory cells in interstinum. We further analyzed death case of NSCLC. Case 3 was 63-year-old female with advanced NSCLC harboring EGFR ex. 19 del. and T790M mutations. After 6 months of osimertinib, she suffered from severe respiratory failure and severely reduced LVEF at 27%. She died on the 44th day after admission. Pathological autopsy revealed mild to moderate cardiomyocyte hypertrophy without inflammatory cell infiltration in both ventricles. These pathological findings may indicate neither myocyte injury nor myocarditis was induced by osimertinib in myocardium.

Conclusion

Although additional data collection of advanced NSCLC patients will be important in understanding the pathophysiology of cardiac AEs with osimertinib, osimertinib-associated cardiotoxicity may result from functional inhibition of myocyte contractility by osimertinib without induction of cell death or inflammation.

Funding Acknowledgement

Type of funding source: None

Photolithographically Constructed Single ZnO Nanowire Device and Its Ultraviolet Photoresponse

A sparse ZnO nanowire array with aspect ratio of ca. 120 and growth rate of 1 μm/h was synthesized by controlling the density of seeds at the initial stage of nanowire growth. The spatially-separated nanowires were cut off from the growth substrate without breaking, and thus were useful in the construction of a single-nanowire device by photolithography. The device exhibited a linear current-voltage characteristic associated with ohmic contact between ZnO nanowire and electrodes. The device further demonstrated a reliable photoresponse with an IUV/Idark of ∼100 to ultraviolet light irradiation.

Mechanical Rupture-Based Antibacterial and Cell-Compatible ZnO/SiO2 Nanowire Structures Formed by Bottom-Up Approaches

There are growing interests in mechanical rupture-based antibacterial surfaces with nanostructures that have little toxicity to cells around the surfaces; however, current surfaces are fabricated via top-down nanotechnologies, which presents difficulties to apply for bio-surfaces with hierarchal three-dimensional structures. Herein, we developed ZnO/SiO2 nanowire structures by using bottom-up approaches and demonstrated to show mechanical rupture-based antibacterial activity and compatibility with human cells. When Escherichia coli were cultured on the surface for 24 h, over 99% of the bacteria were inactivated, while more than 80% of HeLa cells that were cultured on the surface for 24 h were still alive. This is the first demonstration of mechanical rupture-based bacterial rupture via the hydrothermally synthesized nanowire structures with antibacterial activity and cell compatibility.

Monovalent sulfur oxoanions enable millimeter-long single-crystalline h-WO3 nanowire synthesis

Here, we discuss a misunderstanding regarding chemical capping, which has intrinsically hindered the extension of the length of hexagonal (h)-WO₃ nanowires in previous studies. Although divalent sulfate ions (SO₄^2-) have been strongly believed to be efficient capping ions for directing anisotropic h-WO₃ nanowire growth, we have found that the presence of SO₄^2- is highly detrimental to the anisotropic crystal growth of the h-WO₃ nanowires, and a monovalent sulfur oxoanion (HSO₄^-) rather than SO₄^2- only substantially promotes the anisotropic h-WO₃ nanowire growth. Ab initio electronic structure simulations revealed that the monovalent sulfur oxoanions were preferentially able to cap the sidewall plane (100) of the h-WO₃ nanowires due to the lower hydration energy when compared with SO₄^2-. Based on this capping strategy, using the monovalent sulfur oxoanion (CH₃SO₃^-), which cannot generate divalent sulfur oxoanions, we have successfully fabricated ultra-long h-WO₃ nanowires up to the millimeter range (1.2 mm) for a wider range of precursor concentrations. We have demonstrated the feasibility of these millimeter-long h-WO₃ nanowires for the electrical sensing of molecules (lung cancer biomarker: nonanal) on flexible substrates, which can be operated at room temperature with mechanical flexibility with bending cycles up to 10⁴ times due to the enhanced textile effect.

Developing spray-freeze-dried particles containing a hyaluronic acid-coated liposome-protamine-DNA complex for pulmonary inhalation

The liposome-protamine-DNA complex (LPD) is an effective cationic carrier of various nucleic acid constructs such as plasmid DNA and small interfering RNA (siRNA). Hyaluronic acid coated on LPD (LPDH) reduces cytotoxicity and maintains the silencing effect of LPD-encapsulated siRNA. Herein, we aim to develop LPD- or LPDH-containing spray-freeze-dried particles (SFDPs) for therapeutic delivery of siRNA to the lungs. LPD- or LPDH-containing SFDPs (LPD- or LPDH-SFDPs) were synthesized and their structure and function as gene carriers were evaluated using physical and biological methods. The particle size of LPDH, but not of LPD, was constant after re-dispersal from the SFDPs and the amount of siRNA encapsulated in LPDH was larger than that in LPD after re-dispersal from the SFDPs. The in vitro pulmonary inhalation properties of LPDH-SFDPs and LPD-SFDPs were almost the same. The cytotoxicity of LPDH-SFDPs in human umbilical vein endothelial cells (HUVEC) was greatly decreased compared with that of LPD-SFDPs. In addition, Bcl-2 siRNA in LPDH-SFDPs had a significant gene silencing effect in human lung cancer cells (A549), whereas Bcl-2 siRNA in LPD-SFDPs had little effect. These results indicate that compared with LPD, LPDH is more useful for developing SFDPs for siRNA pulmonary inhalation.

A Method to Analyze Urinary Extracellular Vesicles

Extracellular vesicles (EVs) play an important role in cell-to-cell communication by carrying molecular messages that reflect physiological and pathological conditions of the parent cells. EVs have been identified in all body fluids; and among them, urine stands out as a sample that is easy and inexpensive to obtain and can be collected over time to monitor changes. Various protocols have been established to study urinary extracellular vesicles (UEVs) and they have shown great potential as a biomarker source for clinical applications, not only for urological, but also non-urological diseases. Due to the high variability and low reproducibility of pre-analytical and analytical methods for UEVs, establishing a standardized protocol remains a challenge in the field of diagnosis. Here, we review UEV studies and present the techniques that are most commonly used, those that have been applied as new developments, and those that have the most potential for future applications. The workflow procedures from the sampling step to the qualitative and quantitative analysis steps are summarized along with advantages and disadvantages of the methodologies, in order to give consideration for choosing the most promising and suitable method to analyze human UEVs.

Mechanical Low-Pass Filtering of Cells for Detection of Circulating Tumor Cells in Whole Blood

The detection of circulating tumor cells (CTCs) from liquid biopsies using microfluidic devices is attracting a considerable amount of attention as a new, less-invasive cancer diagnostic and prognostic method. One of the drawbacks of the existing antibody-based detection systems is the false negatives for epithelial cell adhesion molecule detection of CTCs. Here we report a mechanical low-pass filtering technique based on a microfluidic constriction and electrical current sensing system for the novel CTC detection in whole blood without any specific antigen-antibody interaction or biochemical modification of the cell surface. The mechanical response of model cells of CTCs, such as HeLa, A549, and MDA-MB-231 cells, clearly demonstrated different behaviors from that of Jurkat cells, a human T-lymphocyte cell line, when they passed through the 6-μm wide constriction channel. A 6-μm wide constriction channel was determined as the optimum size to identify CTCs in whole blood with an accuracy greater than 95% in tens of milliseconds. The mechanical filtering of cells at a single cell level was achieved from whole blood without any pretreatment (e.g., dilution of lysing) and prelabeling (e.g., fluorophores or antibodies).

Synthesis of Monodispersedly Sized ZnO Nanowires from Randomly Sized Seeds

We demonstrate the facile, rational synthesis of monodispersedly sized zinc oxide (ZnO) nanowires from randomly sized seeds by hydrothermal growth. Uniformly shaped nanowire tips constructed in ammonia-dominated alkaline conditions serve as a foundation for the subsequent formation of the monodisperse nanowires. By precisely controlling the sharp tip formation and the nucleation, our method substantially narrows the distribution of ZnO nanowire diameters from σ = 13.5 nm down to σ = 1.3 nm and controls their diameter by a completely bottom-up method, even initiating from randomly sized seeds. The proposed concept of sharp tip based monodisperse nanowires growth can be applied to the growth of diverse metal oxide nanowires and thus paves the way for bottom-up grown metal oxide nanowires-integrated nanodevices with a reliable performance.

PATH-36. MACHINE LEARNING TO DETECT GLIOMAS IN URINE-BASED LIQUID BIOPSY

BACKGROUND

Diffuse gliomas are the most common primary malignant brain tumors, whose overall prognosis is quite dismal. Tumor-cell-secreted extracellular vesicles (EVs) participate in physiological and pathological processes and have potential applications to diagnostics of malignant tumors including diffuse gliomas. Because urine is less invasive to collect, development of early diagnosis based on urine EVs is eagerly awaited. In this study, we captured urine EVs of patients with gliomas efficiently with the nanowire device and compared expression profile of microRNAs (miRNAs) within urine EVs with that of healthy donors to identify diagnostic accuracy by a machine learning algorithm.

METHODS

62 patients with diffuse gliomas, including 27 glioblastoma and 35 lower grade gliomas, and 100 healthy donors were analyzed, along with orthotopic transplant mouse model. Urinary EVs were obtained with the nanowire device which could collect EVs more efficiently than the conventional ultracentrifugation method (Yasui et.al., Science Adv.2017). Machine learning methods were performed to select the miRNAs which could distinguish patients with gliomas from healthy control.

RESULTS

More than 2400 miRNAs were obtained from all urine samples. We identified miRNA panels that provided high diagnostic accuracy of diffuse gliomas (92.5%). There were 440 miRNAs whose expression increased by more than 1.5 fold (p< 0.05) as compared to healthy donor samples (glioma-upregulated miRNAs), whereas the expression of 87 miRNAs decreased to less than 2/3-fold (p< 0.05) (glioma-downregulated miRNAs). Mouse miRNAs which were homologous to glioma-upregulated and -downregulated miRNAs showed significantly high and low level expressions, respectively, in glioma mouse models as compared to normal control mice, confirming the reliability of urine miRNA-based diagnosis. Furthermore, some of these glioma-upregulated miRNAs has been reported to be involved in tumor progression.

CONCLUSIONS

miRNAs obtained from urine could be biomarkers for detection of gliomas by machine learning and some of these could be associated with tumor progression.

P1570Cardiac strain detects subclinical decline of cardiac function after hematopoietic stem cell transplantation in patients with hematologic malignancies

Background

Hematopoietic stem cell transplantation (HSCT) has been established as a treatment of various hematologic malignancies and improved their prognoses. HSCT includes intensive chemotherapy and systemic radiation, which occasionally induces cardiac dysfunction. However, early predictor of cardiac dysfunction associated with HSCT is still elusive. Recently, left ventricular (LV) global longitudinal strain (GLS) has been recognized as an early detector of cardiotoxicity. In this study, we retrospectively analyzed GLS and cardiac parameters in patients with hematologic malignancies before and after HSCT to explore HSCT-induced cardiac dysfunction.

Methods

Thirty-one consecutive patients undergone HSCT were enrolled and reviewed their cardiac comorbidities, medications, chemotherapy, and radiotherapy before HSCT. Transthoracic echocardiographic variables including GLS, cardiac troponin-I, and B-type natriuretic peptide were analyzed prior to and 1 month after HSCT.

Results

The patients were 49.7±13.5 years of age, 61% were male, and 52% had cardiovascular risk factors. Cardiac troponin-I was significantly increased following HSCT from 0.010±0.002 ng/ml to 0.016±0.014 ng/ml (P=0.02), indicating that HSCT should have certain impact on cardiac myocytes. Echocardiographic analyses revealed that LV GLS was significantly decreased after HSCT from −19.4±0.8% to −18.8±0.8% (P<0.001), whereas there was no significant difference in LV ejection fraction between these time points of HSCT (63.6±5.5% vs. 64.7±4.6%; P=0.13). Although there was no correlation between the decline of GLS and the increase of troponin-I in this cohort, these results clearly indicated that GLS, but not LVEF, predicted HSCT-induced early and subclinical cardiac dysfunction at 1 month after the HSCT.

Conclusion

GLS detected early decline of cardiac function after HSCT in the patients with hematologic malignancies. Further follow-up investigations will reveal relationship between GLS, troponin-I and prognosis of cardiac function after HSCT in patients with hematologic malignancies.

Microfluidic Mechanotyping of a Single Cell with Two Consecutive Constrictions of Different Sizes and an Electrical Detection System

The mechanical properties of a cell, which include parameters such as elasticity, inner pressure, and tensile strength, are extremely important because changes in these properties are indicative of diseases ranging from diabetes to malignant transformation. Considering the heterogeneity within a population of cancer cells, a robust measurement system at the single cell level is required for research and in clinical purposes. In this study, a potential microfluidic device for high-throughput and practical mechanotyping were developed to investigate the deformability and sizes of cells through a single run. This mechanotyping device consisted of two different sizes of consecutive constrictions in a microchannel and measured the size of cells and related deformability during transit. Cell deformability was evaluated based on the transit and on the effects of cytoskeleton-affecting drugs, which were detected within 50 ms. The mechanotyping device was able to also measure a cell cycle without the use of fluorescent or protein tags.

Water-Organic Cosolvent Effect on Nucleation of Solution-Synthesized ZnO Nanowires

Here, we show the effect of water-organic (acetone, tert-butyl alcohol, and isopropanol) cosolvents on nucleation and anisotropic crystal growth of solution-synthesized ZnO nanowires. The addition of organic solution does not alter the face-selective crystal growth nature but significantly promotes the crystal growth of both length and diameter of the nanowires. Systematic investigations reveal that a variation of the relative dielectric constant in the cosolvent can rigorously explain the observed effect of the water-organic cosolvent on the ZnO nanowire growth via the degree of supersaturation for the nucleation. The difference between acetone, tert-butyl alcohol, and isopropanol on the cosolvent effect can be interpreted in terms of a local solvent-sorting effect.

Rational Method of Monitoring Molecular Transformations on Metal-Oxide Nanowire Surfaces

Metal-oxide nanowires have demonstrated excellent capability in the electrical detection of various molecules based on their material robustness in liquid and air environments. Although the surface structure of the nanowires essentially determines their interaction with adsorbed molecules, understanding the correlation between an oxide nanowire surface and an adsorbed molecule is still a major challenge. Herein, we propose a rational methodology to obtain this information for low-density molecules adsorbed on metal oxide nanowire surfaces by employing infrared p-polarized multiple-angle incidence resolution spectroscopy and temperature-programmed desorption/gas chromatography-mass spectrometry. As a model system, we studied the surface chemical transformation of an aldehyde (nonanal, a cancer biomarker in breath) on single-crystalline ZnO nanowires. We found that a slight surface reconstruction, induced by the thermal pretreatment, determines the surface chemical reactivity of nonanal. The present results show that the observed surface reaction trend can be interpreted in terms of the density of Zn ions exposed on the nanowire surface and of their corresponding spatial arrangement on the surface, which promotes the reaction between neighboring adsorbed molecules. The proposed methodology will support a better understanding of complex molecular transformations on various nanostructured metal-oxide surfaces.

Appropriate management of high-flow priapism based on color Doppler ultrasonography findings in pediatric patients: four case reports and a review of the literature

INTRODUCTION

High-flow priapism in children is a very rare condition, and there is no clear consensus on its management. High-flow priapism is associated with increased cavernosal blood flow and broadly divided into two groups based on the presence or absence of arteriocavernous fistula in the corpora cavernosa.

OBJECTIVE

This study aimed to determine the appropriate management of high-flow priapism based on the existence of arteriocavernous fistula using penile color Doppler ultrasonography (CDU) findings in the pediatric population.

STUDY DESIGN

The cases of four boys aged between 6 and 11 years with high-flow priapism treated between 2009 and 2017 are reported. Two boys had prior perineal trauma, one boy had blunt penile glans trauma, and one had no obvious cause for the condition. All boys initially underwent penile CDU and were treated conservatively or via selective arterial embolization depending upon the presence or absence of an arteriocavernous fistula.

RESULTS

Penile CDU revealed an arteriocavernous fistula inside the corpus cavernosum penis in two of four boys and increased blood flow inside the corpus spongiosum in the remaining boys. The former two boys underwent selective arterial embolization and one boy underwent repeated embolization because of remaining arteriocavernous fistula feeding from the contralateral cavernosal artery, whereas the boys with no arteriocavernous fistula on CDU were managed conservatively. All boys were successfully treated within 1 month, and they had normal morning erection and no evidence of recurrent priapism at the follow-up.

DISCUSSION

Unlike low-flow priapism, high-flow priapism is not a medical emergency. Therefore, conservative therapy is an appropriate initial treatment, although selective arterial embolization can be effective for high-flow priapism with arteriocavernous fistula, with a success rate of 97% and no reported complications to date. Penile CDU is an imaging technique that can detect focal areas of turbulent flow with sensitivity close to 100%. This study has several limitations including a small number of cases, limited follow-up duration, and possibility of spontaneous arteriocavernous fistula closure in cases treated by arterial embolization.

CONCLUSION

Penile CDU could be a reliable tool to diagnose high-flow priapism and detect the presence or absence of arteriocavernous fistula. Although conservative therapy remains the first choice, selective arterial embolization may be an early treatment option when CDU reveals an arteriocavernous fistula.