Role of miRNA­122 in cancer (Review).

MicroRNAs (miRNAs) are small non­coding RNAs that serve key roles in cell proliferation, migration, invasion and apoptosis by regulating gene expression. In malignant tumors, miRNA­122 serves either as a tumor suppressor or oncogene, influencing tumor progression via downstream gene targeting. However, the precise role of miRNA­122 in cancer remains unclear. miRNA­122 is a potential biomarker and modulator of radiotherapy and chemotherapy. The present review aimed to summarize the roles of miRNA­122 in cancer, its potential as a biomarker for diagnosis and prognosis and its implications in cancer therapy, including radiotherapy and chemotherapy, alongside strategies for systemic delivery.

Pneumonia detection based on RSNA dataset and anchor-free deep learning detector.

Pneumonia is a highly lethal disease, and research on its treatment and early screening tools has received extensive attention from researchers. Due to the maturity and cost reduction of chest X-ray technology, and with the development of artificial intelligence technology, pneumonia identification based on deep learning and chest X-ray has attracted attention from all over the world. Although the feature extraction capability of deep learning is strong, existing deep learning object detection frameworks are based on pre-defined anchors, which require a lot of tuning and experience to guarantee their excellent results in the face of new applications or data. To avoid the influence of anchor settings in pneumonia detection, this paper proposes an anchor-free object detection framework and RSNA dataset based on pneumonia detection. First, a data enhancement scheme is used to preprocess the chest X-ray images; second, an anchor-free object detection framework is used for pneumonia detection, which contains a feature pyramid, two-branch detection head, and focal loss. The average precision of 51.5 obtained by Intersection over Union (IoU) calculation shows that the pneumonia detection results obtained in this paper can surpass the existing classical object detection framework, providing an idea for future research and exploration.

Portable Microwave-Acoustic Coaxial Thermoacoustic Probe With Miniaturized Vivaldi Antennas for Breast Tumor Screening.

Microwave-induced thermoacoustic (TA) imaging (MTAI), which exploits dielectric contrasts to provide images with high contrast and spatial resolution, holds the potential to serve as an additional means of clinical diagnosis and treatment. However, conventional MTAI usually uses large and heavy metal antennas to radiate pulsed microwaves, making it challenging to image different target areas flexibly. In this work, we presented the design and evaluation of a portable microwave-acoustic coaxial TA probe (51 mm × 63 mm × 138 mm) that can flexibly image the region of interest. The TA probe contains two miniaturized symmetrically distributed Vivaldi antennas (7.5 g) and a 128-element linear ultrasonic transducer. By adjusting the geometry of the antennas and the ultrasonic transducer, the TA probe's acoustic field and microwave field can be designed to be coaxial, which helps achieve homogeneous microwave illumination and high-sensitivity ultrasonic detection. The practical feasibility of the proposed probe was tested on an in vitro ewe breast and a healthy volunteer. The results demonstrate that the MTAI system with the proposed TA probe can visualize the anatomical structure of the breast tumor in ewe breast and a healthy volunteer breast with resolutions in hundreds of microns (transverse: 910 µm, axial: 780 µm) and an excellent signal-to-noise ratio can be obtained in deep adipose tissue (10 dB in 6 cm fat). The miniaturized portable TA probe takes a solid step forward in translating MTAI technology to clinical breast tumor diagnosis.

A Handheld Microwave Thermoacoustic Imaging System With an Impedance Matching Microwave-Sono Probe for Breast Tumor Screening.

Microwave-induced thermoacoustic imaging (MTAI) is a promising alternative for breast tumor detection due to its deep imaging depth, high resolution, and minimal biological hazards. However, due to the bulky size and complicated system configuration of conventional benchtop MTAI, it is limited to imaging various anatomical sites and its application in different clinical scenarios. In this study, a handheld MTAI system equipped with a compact impedance matching microwave-sono and an ergonomically designed probe was presented and evaluated. The probe integrates a flexible coaxial cable for microwave delivery, a miniaturized microwave antenna, a linear transducer array, and wedge-shaped polystyrene blocks for efficient acoustic coupling, achieving microwave illumination and ultrasonic detection coaxially, and enabling high signal-to-noise ratio (SNR). Phantom experiments demonstrated that the maximum imaging depth is 5 cm (SNR = 8 dB), and the lateral and axial resolutions are 1.5 mm and 0.9 mm, respectively. Finally, three healthy female volunteers of different ages were subjected to breast thermoacoustic tomography and ultrasound imaging. The results showed that the h-MTAI data are correlated with the data of ultrasound imaging, indicating the safety and effectiveness of the system. Thus, the proposed h-MTAI system might contribute to breast tumor screening.

An Excitation-Reception Collinear Probe for Ultrasonic, Photoacoustic, and Thermoacoustic Tri-Modal Volumetric Imaging.

Imaging systems that integrate multiple modalities can reveal complementary anatomic and functional information as they exploit different contrast mechanisms, which have shown great application potential and advantages in preclinical studies. A portable and easy-to-use imaging probe will be more conducive to transfer to clinical practice. Here, we present a tri-modal ultrasonic (US), photoacoustic (PA), and thermoacoustic (TA) imaging system with an excitation-reception collinear probe. The acoustic field, light field, and electric field of the probe were designed to be coaxial, realizing homogeneous illumination and high-sensitivity detection at the same detection position. US images can provide detailed information about structures, PA images can delineate the morphology of blood vessels in tissues, and TA images can reveal dielectric properties of the tissues. Moreover, phantoms and in vivo human finger experiments were performed by the tri-modal imaging system to demonstrate its performance. The results show that the tri-modal imaging system with the proposed probe has the ability to detect small breast tumors with a radius of only 2.5 mm and visualize the anatomical structure of the finger in three dimensions. Our work confirms that the tri-modal imaging system equipped with a collinear probe can be applied to a variety of different scenarios, which lays a solid foundation for the application of the tri-modality system in clinical trials.

Photoacoustic-immune therapy with a multi-purpose black phosphorus-based nanoparticle.

Effective therapeutic strategies to precisely eradicate primary tumors with minimal side effects on normal tissue, inhibit metastases, and prevent tumor relapses, are the ultimate goals in the battle against cancer. We report a novel therapeutic strategy that combines adjuvant black phosphorus nanoparticle-based photoacoustic (PA) therapy with checkpoint-blockade immunotherapy. With the mitochondria targeting nanoparticle, PA therapy can achieve localized mechanical damage of mitochondria via PA cavitation and thus achieve precise eradication of the primary tumor. More importantly, PA therapy can generate tumor-associated antigens via the presence of the R848-containing nanoparticles as an adjuvant to promote strong antitumor immune responses. When combined with the checkpoint-blockade using anti-cytotoxic T-lymphocyte antigen-4, the generated immunological responses will further promote the infiltrating CD8 and CD4 T-cells to increase the CD8/Foxp3 T-cell ratio to inhibit the growth of distant tumors beyond the direct impact range of the PA therapy. Furthermore, the number of memory T cells detected in the spleen is increased, and these cells inhibit tumor recurrence. This proposed strategy offers precise eradication of the primary tumor and can induce long-term tumor-specific immunity. Electronic Supplementary Material: Supplementary material is available for this article at 10.1007/s12274-020-3028-x and is accessible for authorized users.

A stimulated liquid-gas phase transition nanoprobe dedicated to enhance the microwave thermoacoustic imaging contrast of breast tumors.

Microwave-induced thermoacoustic imaging (MTAI), combining the advantages of the high contrast of microwave imaging and the high resolution of ultrasonic imaging, is a potential candidate for breast tumor detection. MTAI probes have been used to extend thermoacoustic imaging to molecular imaging. However, due to the high content of water molecules in tissues, the thermoelastic expansion-based probes used in conventional MTAI are not capable of adequate enhancement. Herein, an MTAI nanoprobe for amplification of thermoacoustic (TA) signals by the stimulated liquid-gas phase transition mechanism has been developed, providing significantly higher signal amplitude than that from the conventional mechanism of thermoelastic expansion. The nanoprobe consists of liquid perfluorohexane (PFH) and tungsten disulfide (WS2) nanoparticles rich in defect electric dipoles. When irradiated with pulsed microwaves, the defect electric dipoles in WS2 were repeatedly polarized by gigahertz. This results in localized transient heating and an acoustic shockwave, which destroys the van der Waals forces between PFH molecules. Ultimately, liquid PFH droplets undergo a liquid-gas phase transition, generating dramatically enhanced TA signals. The practical feasibility was tested in vitro and in a breast tumor animal model. The results show that the proposed nanoprobe can greatly improve the contrast of tumor imaging. It will be a new generation probe for MTAI.

[Quantitative determination of voglibose contents in its tablets with high-performance liquid chromatography-mass spectrometry].

OBJECTIVE: To develop a method for determination of voglibose contents in its tablets by high-performance liquid chromatography-mass spectrometry (HPLC-MS). METHODS: The measurements were carried out on an Agilent ZORBAX Eclipse Plus C18 column (2.1×150mm 3.2µm) with a temperature of 40 degrees Celsius. A mixture of methanol and water (2:3,v/v) was used as a mobile phase at a flow rate of 0.25 ml/min. Voglibose was detected in an electrospray ionization (ESI) mode with MRM. RESULTS: The calibration curves of voglibose showed good linearity in a range of 1.5804-2.6340 µg/ml (r=0.9990). The average recovery was 100.2% with RSD of 1.37% (n=6) for m/z 268.2/74.2.Linearity was obtained with r=0.9976 and the average recovery was 99.3% with RSD of 1.78% (n=6) for m/z 268.2/92.2. CONCLUSION: HPLC-MS method is accurate,reproducible and can be used for quality control of voglibose tablets.