High-Speed Photoacoustic Microscopy In Vivo

The overarching goal of this research is to develop a novel photoacoustic microscopy: PAM) technology capable of high-speed, high-resolution 3D imaging in vivo. PAM combines the advantages of optical absorption contrast and ultrasonic resolution for deep imaging beyond the quasi-ballistic regime. Its high sensitivity to optical absorption enables the imaging of important physiological parameters, such as hemoglobin concentration and oxygen saturation, which closely correlate with angiogenesis and hypermetabolism--two hallmarks of cancer. To translate PAM to the clinic, both high imaging speed and high spatial resolution are desired. With high spatial resolution, PAM can detect small structural and functional changes early; whereas, high-speed image acquisition helps reduce motion artifacts, patient discomfort, cost, and potentially the risks associated with minimally invasive procedures such as endoscopy and intravascular imaging. To achieve high imaging speed, we have constructed a PAM system using a linear ultrasound array and a kHz-repetition-rate tunable laser. The system has achieved a 249-Hz B-scan rate and a 0.5-Hz 3D imaging rate: over ~6 mm × 10 mm × 3 mm), over 200 times faster than existing mechanical scanning PAM using a single ultrasonic transducer. In addition, high-speed optical-resolution photoacoustic microscopy: OR-PAM) technology has been developed, in which the spatial resolution in one or two dimension(s) is defined by the diffraction-limited optical focus. Using section illumination, the elevational resolution of the system has been improved from ~300 micron to ~28 micron, resulting in a significant improvement in the 3D image quality. Furthermore, multiple optical foci with a microlens array have been used to provide finer than 10-micron lateral resolution--enabling the system to image capillary-level microvessels in vivo--while offering a speed potentially 20 times faster than previously existing single-focus OR-PAM. Finally, potential biomedical applications of the developed technology have been demonstrated through in vivo imaging of murine sentinel lymph nodes, microcirculation dynamics, and human pulsatile dynamics. In the future, this high-speed PAM technology may be adapted for clinical imaging of diabetes-induced vascular complications or tumor angiogenesis, or miniaturized for gastrointestinal or intravascular applications

Imaging Sensors and Applications

In past decades, various sensor technologies have been used in all areas of our lives, thus improving our quality of life. In particular, imaging sensors have been widely applied in the development of various imaging approaches such as optical imaging, ultrasound imaging, X-ray imaging, and nuclear imaging, and contributed to achieve high sensitivity, miniaturization, and real-time imaging. These advanced image sensing technologies play an important role not only in the medical field but also in the industrial field. This Special Issue covers broad topics on imaging sensors and applications. The scope range of imaging sensors can be extended to novel imaging sensors and diverse imaging systems, including hardware and software advancements. Additionally, biomedical and nondestructive sensing applications are welcome

Imaging in Women\u27s Health

Women’s health is a large area of the medical field that is continuing to see growth and technological advancement. Gynecological, obstetric, and breast health are fields that are always in demand, and imaging plays a large role in caring for patients in these fields. This paper will discuss different areas of women’s health and explain how imaging can be used to assist in diagnosis and treatment. Imaging can include MRI, 2D ultrasound, 3D ultrasound, and x-ray. This paper will discuss basic gynecological health, complications that can arise in gynecological health, women’s health in college, preconception care, obstetrics, obstetric complications, breast health, post menopausal health, and other women’s health issues. Some topics discussed will be endometriosis, adenomyosis, breast cancer screening and treatment, endometrial cancer, pregnancy, pelvic floor health, and ovarian masses. It will also discuss the future of women’s health. From basic gynecological health through pregnancy, breast health and menopause, imaging is a vital tool used to help medical professionals diagnose, monitor and treat women through many stages of life

Goggle Augmented Imaging and Navigation System for Fluorescence-Guided Surgery

Surgery remains the only curative option for most solid tumors. The standard-of-care usually involves tumor resection and sentinel lymph node biopsy for cancer staging. Surgeons rely on their vision and touch to distinguish healthy from cancer tissue during surgery, often leading to incomplete tumor resection that necessitates repeat surgery. Sentinel lymph node biopsy by conventional radioactive tracking exposes patients and caregivers to ionizing radiation, while blue dye tracking stains the tissue highlighting only superficial lymph nodes. Improper identification of sentinel lymph nodes may misdiagnose the stage of the cancer. Therefore there is a clinical need for accurate intraoperative tumor and sentinel lymph node visualization. Conventional imaging modalities such as x-ray computed tomography, positron emission tomography, magnetic resonance imaging, and ultrasound are excellent for preoperative cancer diagnosis and surgical planning. However, they are not suitable for intraoperative use, due to bulky complicated hardware, high cost, non-real-time imaging, severe restrictions to the surgical workflow and lack of sufficient resolution for tumor boundary assessment. This has propelled interest in fluorescence-guided surgery, due to availability of simple hardware that can achieve real-time, high resolution and sensitive imaging. Near-infrared fluorescence imaging is of particular interest due to low background absorbance by photoactive biomolecules, enabling thick tissue assessment. As a result several near-infrared fluorescence-guided surgery systems have been developed. However, they are limited by bulky hardware, disruptive information display and non-matched field of view to the user. To address these limitations we have developed a compact, light-weight and wearable goggle augmented imaging and navigation system (GAINS). It detects the near-infrared fluorescence from a tumor accumulated contrast agent, along with the normal color view and displays accurately aligned, color-fluorescence images via a head-mounted display worn by the surgeon, in real-time. GAINS is a platform technology and capable of very sensitive fluorescence detection. Image display options include both video see-through and optical see-through head-mounted displays for high-contrast image guidance as well as direct visual access to the surgical bed. Image capture options from large field of view camera as well high magnification handheld microscope, ensures macroscopic as well as microscopic assessment of the tumor bed. Aided by tumor targeted near-infrared contrast agents, GAINS guided complete tumor resection in subcutaneous, metastatic and spontaneous mouse models of cancer with high sensitivity and specificity, in real-time. Using a clinically-approved near-infrared contrast agent, GAINS provided real-time image guidance for accurate visualization of lymph nodes in a porcine model and sentinel lymph nodes in human breast cancer and melanoma patients with high sensitivity. This work has addressed issues that have limited clinical adoption of fluorescence-guided surgery and paved the way for research into developing this approach towards standard-of-care practice that can potentially improve surgical outcomes in cancer

Research Topics in Medicines and How Our Board Members Are Engaged in Them

With the development of analytical instruments, the academic system has become more complicated, producing new journals one after another. Therefore, it became much important to clarify what is original of “Medicines”. As the name Medicines indicates, it includes science and practice of caring for a patient and managing the diagnosis, prognosis, prevention, treatment or palliation of their injury or disease. Therefore, Medicines differs from other journals with similar title in that it covers a wide range of fields, from traditional medicine to rapidly developing molecular-targeted drugs, focusing on their pharmacological effects, structure–activity relationships, metabolic pathways, gene expression, using cultured cells, animals, and clinical trials. Most parts of this Special Issue were written by our editorial board members, who described the research topics and how they are engaged in their field of research. All of these articles are their life-long story. We collected a total number of 22 original works by basic researchers and clinical doctors. We hope that readers can get a chance to know the current status of diverse fields of medicines, and what your most important research themes are after reading these articles

Voltage-gated potassium channel dependent mechanisms of cardiovascular adaptation to chronic exercise.

Exercise increases cardiac workload, escalating the demand for oxygen. The myocardial vasculature responds to the greater demand for oxygen by increasing blood flow to match the needs of the heart during augmented work. Increasing blood flow requires the coronary arteries dilate (a.k.a. vasodilation); this is mediated predominantly by vascular smooth muscle cell relaxation. Vasodilation is driven through inhibition of calcium influx into vascular smooth muscle cells. The prevention of calcium influx is largely mediated by efflux of potassium via potassium channels causing membrane hyperpolarization, which in turn closes voltage-dependent (or gated) calcium channels (VDCC). Changes in vascular smooth muscle cell membrane potential are influenced by the movement of potassium ions through K+ channels such as the voltage gated potassium (Kv) channels. Kv channels form heteromeric octomeric complexes consisting of four membrane bound α-subunits that comprise the voltage-sensitive pore complex, and associate with four intracellular auxiliary β-subunits (Κvβ). The auxiliary β-subunits are members of the aldo-keto reductase (AKR) super family, enzymes that catalytically react with carbonyl substrates. These β-subunits sense changes in oxygen availability, metabolic signal transducer ratios (e.g., NADH:NAD+) and metabolites (e.g., H2O2). In this study I investigated the role of Kv channels and their auxiliary Kvβ2 subunits in vasodilation response to conditions of altered metabolism, physiological cardiac adaptation, and myocardial blood flow in response to 4 weeks of exercise. I found that Kvβ2 is necessary to induce Kv driven vasodilation under hypoxic conditions. Loss of Kvβ2 significantly impaired exercise capacity in both naïve and 4-week exercised (exe) mice, relative to sedentary and wildtype controls. Chronic exercise also enhanced myocardial perfusion in WT mice but not Kvβ2-/- male mice. Additionally, 4-weeks of exercise significantly increased Kv1 associated Kvβ2, in proximity ligation assay experiments. In isolated arteries from SM22α-rtTA single transgenic mice, the perfusion of external 10 mM L-lactate in the presence of 10-5 M H2O2 induced significantly greater vasodilation. Interestingly, this effect was not seen in arteries from SM22α-rtTA:TRE β1 double transgenic mice. Administration of NADH and H2O2 induced significant increases in Kv channel open probability (nPo). Additionally, in vascular smooth muscle cells, isolated from SM22α-rtTA mice, externally perfused with 1 mM NADH plus of 10-5 M H2O2 we observed a significant increase in Kv nPo. Hence, we conclude that loss of Kvβ2 impairs vasodilatory capacity in response to conditions that reflect increased work. Also, exercise capacity and myocardial perfusion are impaired in the absence of Kvβ2. Additionally, the increased presence of Kvβ1 relative to Kvβ2 in the Kv channel complex opposes the vasodilatory response to metabolites and signal transducers of increased work (e.g., NADH and H2O2). In conclusion, the presence of the Kvβ2 protein in arterial myocytes is crucial for adaptation following chronic exercise training

Volume 36, issue 5

The mission of CJS is to contribute to the effective continuing medical education of Canadian surgical specialists, using innovative techniques when feasible, and to provide surgeons with an effective vehicle for the dissemination of observations in the areas of clinical and basic science research. Visit the journal website at http://canjsurg.ca/ for more.https://ir.lib.uwo.ca/cjs/1261/thumbnail.jp