Spectral study of metabolism-based autofluorescence and white-light reflectance for endoscopic tumor imaging.

Metabolism-based autofluorescence redox imaging is one of the promising options for non-invasive screening of digestive tumors. In this paper, autofluorescence from fluorescent coenzymes such as NADH and FAD related to cellular metabolism as well as total hemoglobin and oxygen saturation are analyzed based on a point spectrum. As a redox index based on the metabolism, the ratio of the 450nm-490nm fluorescence intensities for 365nm and 405nm excitation wavelengths (F365/F405) is used. Although F365/F405 is a good index in many samples, inversion and weakened contrast are observed. A Simplified models with and without collagen based on Lambert-Beer law are built to explain how F365/F405 depicts the tumor region.

Dual-band multi-aperture enhanced redox imaging of colonic adenomas for endoscopes with a high-performance CMOS imager.

Dual-band multi-aperture imaging of colonic adenomas based on the redox condition of mucosal cells for next-generation endoscopes is proposed. A low-noise and high-dynamic-range CMOS imager with the folding integration and the cyclic ADC is utilized in the single-imager multi-aperture camera system with 475-nm and 530-nm band-pass filters. A redox image is calculated from four kinds of images, 475-nm and 530-nm fluorescence images for 365-nm and 405-nm excitation lights. Dark current and random noise are reduced with a selective averaging method. The contrast of the redox image has been successfully enhanced.

Interface pressure and stiffness in different combinations of compression material.

OBJECTIVES: To compare the interface pressure and stiffness between various combinations of compression material. METHODS: Using a stiffness-determining device, the interface pressure and stiffness were determined in several combinations of five elastic stockings and two elastic bandages. RESULTS: In the double stockings system, the interface pressure increased significantly and the highest stiffness was observed in double short-stretch stockings. When short-stretch bandages were applied over either short- or long-stretch stockings, a significant increase in stiffness was observed at any initial pressure compared with the single use of short-stretch stockings. In double bandage systems, when short-stretch bandages were applied over either short- or long-stretch bandages, the stiffness increased significantly. When long-stretch bandages were used over short-stretch bandages, the stiffness decreased significantly. CONCLUSIONS: The stiffness is changeable according to the combinations of material, such as double stockings, double bandages and the wearing of bandages over stockings. The use of short-stretch bandages as the outside layer produces the highest stiffness at a high initial pressure.

Development of a device to determine the stiffness of elastic garments and bandages.

OBJECTIVE: To evaluate the reliability of a newly developed stiffness-determining device, composed of a leg mannequin and air-pack type analyser, for measuring the interface pressure. METHOD: The correlation of stiffness values obtained employing the Hohenstein method and this new method was investigated using 17 different brands of medical elastic compression stocking. RESULTS: A significant correlation in stiffness values using the two methods was obtained (P < 0.01). When this new method was applied to the bandages, the stiffness was significantly correlated with the initial pressure when assessing both short-stretch and long-stretch bandages. On the comparison of stiffness values between elastic stockings and bandages with the same initial pressure, the short-stretch bandages showed a predominantly higher value than long-stretch bandages and stockings (P < 0.01). CONCLUSION: The reliability of this new method, which can be easily applied to not only elastic stockings but also elastic bandages, was verified. In clinical practice, the compression pressure should be selected in consideration of the prospective stiffness.

Acquisition of a gastric or duodenal phenotype on heterotropic transplantation of esophagus and bladder tissues in F344 rats.

Cell differentiation is very important but not well understood. In the present study the ability of various tissues to newly-differentiate when transplanted into the fundus or the duodenum in rats was tested. Pieces of esophagus, bladder, diaphragm and trachea from 8-week-old male F344 rats were transplanted into the gastric fundus or duodenum of females and examined after 3 or 6 months. While the diaphragm was not recognizable as a muscle layer in either the stomach or the duodenum, the esophagus and trachea persisted, the latter with the presence of cartilage. Esophagus grafts transplanted into the glandular stomach and duodenum, newly-differentiated into gastric and duodenal mucosa, respectively. Goblet cells with alcian-blue positive mucin appeared in bladder tissue implanted into the duodenum. Six months after the operation, their numbers had increased and cytoplasm alkaline phosphatase (ALP) positivity was noted. Gastrointestinal and also bladder stem cells may thus have multipotential ability for differentiation and may be able to newly-differentiate when transplanted into different environments in the gastrointestinal tract.