Abstract During treatment of leukemia, side effects create a great burden for patients. Therefore, new therapies to replace conventional chemotherapy and hematopoietic stem cell transplantation are ...highly desirable. In a previous study, I found that ultraviolet irradiation at 365 nm induced apoptosis in 98% of leukemia (Jurkat T) cells. To determine the most suitable wavelength for such treatments, it is necessary measure UV light absorption of cancer cells. In this study, a biochip was fabricated and evaluated for this purpose. Three types of leukemic cells (human acute myelogenous leukemia cells, human acute lymphoblastic leukemia cells, and human chronic myelogenous leukemia cells) were injected into the biochip and light absorption was measured, revealing that individual leukemic cells have different light absorption characteristics. This variation is important in order to develop an implant care device to treat leukemia more effectively.
Podoplanin is distinctively overexpressed in oral squamous cell carcinoma than oral benign neoplasms and plays a crucial role in the pathogenesis and metastasis of oral squamous cell carcinoma but ...its diagnostic application is quite limited. Here, we report a new near-infrared fluorescence imaging method using an indocyanine green (ICG)–labeled anti-podoplanin antibody and a desktop/a handheld ICG detection device for the visualization of oral squamous cell carcinoma–xenografted tumors in nude mice. Both near-infrared imaging methods using a desktop (in vivo imaging system: IVIS) and a handheld device (photodynamic eye: PDE) successfully detected oral squamous cell carcinoma tumors in nude mice in a podoplanin expression–dependent manner with comparable sensitivity. Of these 2 devices, only near-infrared imaging methods using a handheld device visualized oral squamous cell carcinoma xenografts in mice in real time. Furthermore, near-infrared imaging methods using the handheld device (PDE) could detect smaller podoplanin-positive oral squamous cell carcinoma tumors than a non-near-infrared, autofluorescence-based imaging method. Based on these results, a near-infrared imaging method using an ICG-labeled anti-podoplanin antibody and a handheld detection device (PDE) allows the sensitive, semiquantitative, and real-time imaging of oral squamous cell carcinoma tumors and therefore represents a useful tool for the detection and subsequent monitoring of malignant oral neoplasms in both preclinical and some clinical settings.
Laparoscopic surgery is now a standard treatment for gastric cancer. Currently, the location of the gastric cancer is identified during laparoscopic surgery via the preoperative endoscopic injection ...of charcoal ink around the primary tumor; however, the wide spread of injected charcoal ink can make it difficult to accurately visualize the specific site of the tumor. To precisely identify the locations of gastric tumors, we developed a fluorescent detection system comprising clips with glass phosphor (Yb
, Nd
doped to Bi₂O₃-B₂O₃-based glasses, size: 2 mm × 1 mm × 3 mm) fixed in the stomach and a laparoscopic fluorescent detection system for clip-derived near-infrared (NIR) light (976 nm). We conducted two ex vivo experiments to evaluate the performance of this fluorescent detection system in an extirpated pig stomach and a freshly resected human stomach and were able to successfully detect NIR fluorescence emitted from the clip in the stomach through the stomach wall by the irradiation of excitation light (λ: 808 nm). These results suggest that the proposed combined NIR light-emitting clip and laparoscopic fluorescent detection system could be very useful in clinical practice for accurately identifying the location of a primary gastric tumor during laparoscopic surgery.
Cell counters, which are dedicated cell analyzers, can be used to analyze cellular status. Cell counters are smaller and less expensive (about $13,000) than other cell analysis devices such as flow ...cytometers (FACS), real-time PCR, and sequencers, and can discriminate between life and death of fluorescently stained cells. Cell death can be roughly divided into two types: apoptosis and necrosis, but Cell counters cannot distinguish between apoptosis and necrosis in cells. This study developed a biochip system for inexpensive, simple, and capable of distinguishing between live, apoptotic, and necrotic cells. This biochip system (70 x 150 x 80 mm) comprises a slide into which fluorescently stained cells are injected, an LED light source, and a camera system. When cells stained with a fluorescent reagent are irradiated at the excitation wavelength, they fluoresce. By changing the combination of fluorescent reagent and excitation wavelength, live, apoptotic, and necrotic cells can be photographed. Then they are processed by a cell counting program using existing methods to determine numbers of live, dead, and necrotic cells. To demonstrate the effectiveness of this system, we conducted live cell, apoptosis, and necrosis detection experiments using colon cancer cells. Results of each experiment using the biochip system were compared with visual cell counts made by an operator. The novel biochip system successfully distinguishes between live, apoptotic and necrotic cells. Detection time was <1 s, and the detection error was 9%, compared to visual inspection.
In conventional method, to identify location of the tumor intraperitoneally for extirpation of the gastric cancer, charcoal ink is injected around the primary tumor. However, in the time of ...laparoscopic operation, it is difficult to estimate specific site of primary tumor. In this study we developed a glass phosphors was realized with Yb3+, Nd3+ doped to Bi2O3-B2O3 based glasses, which have central emission wavelength of 1020 nm and 100 nm of FWHM. Using this glass phosphor, we developed a fluorescent clip and the laparoscopic fluorescent detection system for clip-derived near-infrared light. To evaluated clinical performance of a fluorescent clip and the laparoscopic detection system, we used resected stomach from the patients. Fluorescent clip was fixed on the gastric mucosa, and an excitation light (wavelength: 808nm) was irradiated from outside of stomach for detection of fluorescent through stomach wall. As a result, fluorescent emission from the clip was successfully detected. These results indicate that the glass fluorescent clip in combination with laparoscopic detection system is a very useful method to identify the exact location of the primary gastric cancer.
We fabricated blue (${\sim}450$ nm), blue-green (${\sim}500$ nm), and green (${\sim}525$ nm) light-emitting diodes (LEDs) of different dislocation densities (DD) and characterized their internal ...quantum efficiency (IQE). The IQE of the blue LEDs fabricated using GaN substrate exceeded 90% (DD: ${\sim}10^{6}$ cm -2 ), however, when we used a GaN-on-sapphire substrate (DD: ${\sim}10^{8}$ cm -2 ), IQE was limited to ${\sim}60$%. Droop was reduced by use of the GaN substrate. The junction temperature of the GaN-on-sapphire substrate was found to be ${\sim}200$ °C although the junction temperature of the GaN substrate was ${\sim}50$ °C when a forward current of 100 A/cm 2 was driven. A lowering of IQE in green LEDs to ${\sim}60$% was observed, even though we used a low-dislocation-density substrate DD: $(1{\mbox{--}}2)\times 10^{7}$ cm -2 . The junction temperature of blue-green and green LEDs was about 100 °C when a forward current of 177 A/cm 2 was driven, which indicated that junction temperature is not a major factor for IQE suppression in green LEDs.
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