ARF-OCE for mapping mechanical properties of ocular and vascular tissues

Elastography is an imaging modality for clinical diagnosis based on the tissue stiffness. Benefiting from the high resolution, three-dimensional, and noninvasive nature of optical coherence tomography (OCT), optical coherence elastography (OCE) has the ability to determine elastic properties with a resolution of ~10 μm in 3D. Typical OCE imaging includes excitation for inducing mechanical vibrations, measurement of the sample response using OCT, and estimation of elastic parameters. Acoustic radiation force (ARF) generated by an ultrasonic transducer can noninvasively excite internal tissues without contact; thus, ARF-OCE is suitable for measuring the mechanical properties in deeper tissues. For assessment of the elastic properties of tissues using ARF-OCE, the shear wave velocity, resonant frequency, and vibrational displacement can be measured. Shear wave velocity measurements can be conveniently used for quantitative calculation of the elastic modulus.1-3 The resonant frequency of a tissue has a squared relationship with the Young\u27s modulus, and thus can quantify the elasticity.4 Vibrational displacement can be compared directly when the same pressure is applied to different samples.5 Several diseases are accompanied by and result in the changes in composition and local geometry of tissues. Keratoconus, which causes vision distortions and blurriness, will change the geometry of the cornea. The development of presbyopia is generally caused by the loss of elasticity in the lens. The composition and biomechanical properties of vessels will usually be altered when atherosclerosis occurs. The ARF-OCE technology provides a new opportunity for the early diagnosis of ocular and vascular diseases. Based on the shear wave measurements, our system can be used to quantify the elastic modulus of the cornea and the crystalline lens. By comparing the vibrational displacement, we have detected the differences between normal and cross-linked cornea.6 Recently we developed a miniature probe for mapping the mechanical properties of vascular lesions using ARF-OCE. It has the ability to detect the a vulnerable plaque due to its higher stiffness.7 Because of the noninvasive nature, ARF-OCE has the potential to perform in vivo imaging of deep tissues for the early diagnosis of ocular and vascular diseases. 1. Zhu, J., Qu, Y., Ma, T., Li, R., Du, Y., Huang, S., Shung, K.K., Zhou, Q. and Chen, Z., 2015. Imaging and characterizing shear wave and shear modulus under orthogonal acoustic radiation force excitation using OCT Doppler variance method. Optics letters, 40(9): 2099-2102. 2. Zhu, J., Qi, L., Miao, Y., Ma, T., Dai, C., Qu, Y., He, Y., Gao, Y., Zhou, Q. and Chen, Z., 2016. 3D mapping of elastic modulus using shear wave optical micro-elastography. Scientific reports, 6: 35499. 3. Xu, X., Zhu, J. and Chen, Z., 2016. Dynamic and quantitative assessment of blood coagulation using optical coherence elastography. Scientific reports, 6: 24294. 4. Qi, W., Li, R., Ma, T., Li, J., Kirk Shung, K., Zhou, Q. and Chen, Z., 2013. Resonant acoustic radiation force optical coherence elastography. Applied physics letters, 103(10): 103704. 5. Qi, W., Li, R., Ma, T., Kirk Shung, K., Zhou, Q. and Chen, Z., 2014. Confocal acoustic radiation force optical coherence elastography using a ring ultrasonic transducer. Applied physics letters, 104(12): 123702. 6. Qu, Y., Ma, T., He, Y., Zhu, J., Dai, C., Yu, M., Huang, S., Lu, F., Shung, K.K., Zhou, Q. and Chen, Z., 2016. Acoustic radiation force optical coherence elastography of corneal tissue. IEEE Journal of Selected Topics in Quantum Electronics, 22(3): 288-294. Qu, Y., Ma, T., He, Y., Yu, M., Zhu, J., Miao, Y., Dai, C., Patel, P., Shung, K.K., Zhou, Q. and Chen, Z., 2017. Miniature probe for mapping mechanical properties of vascular lesions using acoustic radiation force optical coherence elastography. Scientific Reports, 7: 473

Study on Adaptability of Nitrogen Foam to Control Profile in Offshore Oilfield

Water breakthrough is usually occurred during water flooding process as the high porosity and permeability features of offshore oilfield. The adaptability of nitrogen foam improve profile are evaluated based on laboratory experiment and numerical simulation. The effects of formation rhythmicity, permeability ratio, formation dip, layer thickness and crude oil viscosity on profile control by nitrogen foam are investigated. Study results indicated that nitrogen foam is an efficiency approach to enhance the oil recovery of heterogeneity reservoir by block the water channel and improve the profile. Meanwhile, the application field and appropriate conditions of nitrogen foam are summarized which can be used in the optimization of nitrogen foam in offshore oilfield. Key words: Nitrogen foam; Resistance factor; Numerical simulation; Formation rhythmicity; Permeability rati

Using patient-collected clinical samples and sera to detect and quantify the severe acute respiratory syndrome coronavirus (SARS-CoV)

BACKGROUND: Severe acute respiratory syndrome (SARS) caused a large outbreak of pneumonia in Beijing, China, in 2003. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect and quantify SARS-CoV in 934 sera and self-collected throat washes and fecal samples from 271 patients with laboratory-confirmed SARS managed at a single institution. RESULTS: SARS-CoV detection rates in sera were highest in the first 9 days of illness, whereas detection was highest in throat washes 5–14 days after onset of symptoms. The highest SARS-CoV RT-PCR rates (70.4–86.3%) and viral loads (log(10 )4.5–6.1) were seen in fecal samples collected 2–4 weeks after the onset of clinical illness. Fecal samples were frequently SARS-CoV RT-PCR positive beyond 40 days, and occasional sera still had SARS-CoV detected after 3 weeks of illness. CONCLUSION: In the context of an extensive outbreak with major pressure on hospital resources, patient self-collected samples are an alternative to nasopharyngeal aspirates for laboratory confirmation of SARS-CoV infection

Complement and the Alternative Pathway Play an Important Role in LPS/D-GalN-Induced Fulminant Hepatic Failure

Fulminant hepatic failure (FHF) is a clinically severe type of liver injury with an extremely high mortality rate. Although the pathological mechanisms of FHF are not well understood, evidence suggests that the complement system is involved in the pathogenesis of a variety of liver disorders. In the present study, to investigate the role of complement in FHF, we examined groups of mice following intraperitoneal injection of LPS/D-GalN: wild-type C57BL/6 mice, wild-type mice treated with a C3aR antagonist, C5aR monoclonal antibody (C5aRmAb) or CR2-Factor H (CR2-fH, an inhibitor of the alternative pathway), and C3 deficient mice (C3−/− mice). The animals were euthanized and samples analyzed at specific times after LPS/D-GalN injection. The results show that intraperitoneal administration of LPS/D-GalN activated the complement pathway, as evidenced by the hepatic deposition of C3 and C5b-9 and elevated serum levels of the complement activation product C3a, the level of which was associated with the severity of the liver damage. C3a receptor (C3aR) and C5a receptor (C5aR) expression was also upregulated. Compared with wild-type mice, C3−/− mice survived significantly longer and displayed reduced liver inflammation and attenuated pathological damage following LPS/D-GalN injection. Similar levels of protection were seen in mice treated with C3aR antagonist,C5aRmAb or CR2-fH. These data indicate an important role for the C3a and C5a generated by the alternative pathway in LPS/D-GalN-induced FHF. The data further suggest that complement inhibition may be an effective strategy for the adjunctive treatment of fulminant hepatic failure

Lignosulfonic Acid Exhibits Broadly Anti-HIV-1 Activity – Potential as a Microbicide Candidate for the Prevention of HIV-1 Sexual Transmission

Some secondary metabolites from plants show to have potent inhibitory activities against microbial pathogens, such as human immunodeficiency virus (HIV), herpes simplex virus (HSV), Treponema pallidum, Neisseria gonorrhoeae, etc. Here we report that lignosulfonic acid (LSA), a polymeric lignin derivative, exhibits potent and broad activity against HIV-1 isolates of diverse subtypes including two North America strains and a number of Chinese clinical isolates values ranging from 21.4 to 633 nM. Distinct from other polyanions, LSA functions as an entry inhibitor with multiple targets on viral gp120 as well as on host receptor CD4 and co-receptors CCR5/CXCR4. LSA blocks viral entry as determined by time-of-drug addiction and cell-cell fusion assays. Moreover, LSA inhibits CD4-gp120 interaction by blocking the binding of antibodies specific for CD4-binding sites (CD4bs) and for the V3 loop of gp120. Similarly, LSA interacts with CCR5 and CXCR4 via its inhibition of specific anti-CCR5 and anti-CXCR4 antibodies, respectively. Interestingly, the combination of LSA with AZT and Nevirapine exhibits synergism in viral inhibition. For the purpose of microbicide development, LSA displays low in vitro cytotoxicity to human genital tract epithelial cells, does not stimulate NF-κB activation and has no significant up-regulation of IL-1α/β and IL-8 as compared with N-9. Lastly, LSA shows no adverse effect on the epithelial integrity and the junctional protein expression. Taken together, our findings suggest that LSA can be a potential candidate for tropical microbicide

A Biological Global Positioning System: Considerations for Tracking Stem Cell Behaviors in the Whole Body

Many recent research studies have proposed stem cell therapy as a treatment for cancer, spinal cord injuries, brain damage, cardiovascular disease, and other conditions. Some of these experimental therapies have been tested in small animals and, in rare cases, in humans. Medical researchers anticipate extensive clinical applications of stem cell therapy in the future. The lack of basic knowledge concerning basic stem cell biology-survival, migration, differentiation, integration in a real time manner when transplanted into damaged CNS remains an absolute bottleneck for attempt to design stem cell therapies for CNS diseases. A major challenge to the development of clinical applied stem cell therapy in medical practice remains the lack of efficient stem cell tracking methods. As a result, the fate of the vast majority of stem cells transplanted in the human central nervous system (CNS), particularly in the detrimental effects, remains unknown. The paucity of knowledge concerning basic stem cell biology—survival, migration, differentiation, integration in real-time when transplanted into damaged CNS remains a bottleneck in the attempt to design stem cell therapies for CNS diseases. Even though excellent histological techniques remain as the gold standard, no good in vivo techniques are currently available to assess the transplanted graft for migration, differentiation, or survival. To address these issues, herein we propose strategies to investigate the lineage fate determination of derived human embryonic stem cells (hESC) transplanted in vivo into the CNS. Here, we describe a comprehensive biological Global Positioning System (bGPS) to track transplanted stem cells. But, first, we review, four currently used standard methods for tracking stem cells in vivo: magnetic resonance imaging (MRI), bioluminescence imaging (BLI), positron emission tomography (PET) imaging and fluorescence imaging (FLI) with quantum dots. We summarize these modalities and propose criteria that can be employed to rank the practical usefulness for specific applications. Based on the results of this review, we argue that additional qualities are still needed to advance these modalities toward clinical applications. We then discuss an ideal procedure for labeling and tracking stem cells in vivo, finally, we present a novel imaging system based on our experiments

Acoustic radiation force optical coherence elastography for elasticity assessment of soft tissues

Biomechanical properties of soft tissues are important indicators of tissue functions which can be used for clinical diagnosis and disease monitoring. Elastography, incorporating the principles of elasticity measurements into imaging modalities, provides quantitative assessment of elastic properties of biological tissues. Benefiting from high-resolution, noninvasive and three-dimensional optical coherence tomography (OCT), optical coherence elastography (OCE) is an emerging optical imaging modality to characterize and map biomechanical properties of soft tissues. Recently, acoustic radiation force (ARF) OCE has been developed for elasticity measurements of ocular tissues, detection of vascular lesions and monitoring of blood coagulation based on remote and noninvasive ARF excitation to both internal and superficial tissues. Here, we describe the advantages of the ARF-OCE technique, the measurement methods in ARF-OCE, the applications in biomedical detection, current challenges and advances. ARF-OCE technology has the potential to become a powerful tool for in vivo elasticity assessment of biological samples in a non-contact, non-invasive and high-resolution nature