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A metabolic cycle‐inspired hydrogel which exhibits the biomacromolecule‐fueled transient volume phase transition is reported. This hydrogel has the affinity and digestive capacity for a fuel α‐poly‐L‐lysine by incorporating acrylic acid and trypsin. The hydrogel captured fuel and transiently shrank owing to the construction of electrostatic cross‐linkages. This process was inherently connected with the digestion of these cross‐linkages and the release of oligo‐lysine as waste, which induced the reswelling of the hydrogel at equilibrium. The transient volume change of the hydrogel realized the fuel‐stimulated transient release of a payload. This study provides a strategy for engineering materials with biomacromolecule‐fueled dynamic functions under the out‐of‐equilibrium condition. [ABSTRACT FROM AUTHOR]

Objectives To assess the feasibility of a novel percutaneous navigation system ( Translucent Medical, Inc., Santa Cruz, CA, USA) that integrates position-tracking technology with a movable tablet display. Materials and Methods A total of 18 fiducial markers, which served as the target centres for the virtual tumours (target fiducials), were implanted in the prostate and kidney of a fresh cadaver, and preoperative computed tomography ( CT) was performed to allow three-dimensional model reconstruction of the surgical regions, which were registered on the body intra-operatively. The position of the movable tablet's display could be selected to obtain the best recognition of the interior anatomy. The system was used to navigate the puncture needle (with position-tracking sensor attached) using a colour-coded, predictive puncture-line. When the operator punctured the target fiducial, another fiducial, serving as the centre of the ablative treatment (treatment fiducial), was placed. Postoperative CT was performed to assess the digitized distance (representing the real distance) between the target and treatment fiducials to evaluate the accuracy of the procedure. Results The movable tablet display, with position-tracking sensor attached, enabled the surgeon to visualize the three-dimensional anatomy of the internal organs with the help of an overlaid puncture line for the puncture needle, which also had a position-tracking sensor attached. The mean (virtual) distance from the needle tip to the target (calculated using the computer workstation), was 2.5 mm. In an analysis of each digitalized axial component, the errors were significantly greater along the z-axis ( P < 0.01), suggesting that the errors were caused by organ shift or deformation. Conclusion This virtual navigation system, integrating a position-tracking sensor with a movable tablet display, is a promising advancement for facilitating percutaneous interventions. The movable display over the patient shows a preoperative three-dimensional image that is aligned to the patient. Moving the display moves the image, creating the feeling of looking through a window into the patient, resulting in instant perception and a direct, intuitive connection between the physician and the anatomy. [ABSTRACT FROM AUTHOR]

Avascular areas on contrast-enhanced magnetic resonance imaging have been considered to be areas of localized prostate cancer successfully treated by high-intensity focused ultrasound. However, the optimal timing of magnetic resonance imaging has not been discussed. The thermal effect of high-intensity focused ultrasound is degraded by regional prostatic blood flow. Conversely, the mechanical effect of high-intensity focused ultrasound (cavitation) is not affected by blood flow, and can induce vessel damage. In this series, the longitudinal change of blood flow on contrast-enhanced magnetic resonance imaging was observed from postoperative day 1 to postoperative day 14 in 10 patients treated with high-intensity focused ultrasound. The median rates of increase in the non-enhanced volume of the whole gland, transition zone and peripheral zone from postoperative day 1 to postoperative day 14 were 36%, 39%, and 34%, respectively. In another pathological analysis of the prostate tissue of 17 patients immediately after high-intensity focused ultrasound without neoadjuvant hormonal therapy, we observed diffuse coagulative degeneration and partial non-coagulative prostate tissue around arteries with vascular endothelial cell detachment. These observations on contrast-enhanced magnetic resonance imaging support a time-dependent change of the blood flow in the prostate treated with high-intensity focused ultrasound. Additionally, our pathological findings support the longitudinal changes of these magnetic resonance imaging findings. Further large-scale studies will investigate the most appropriate timing of contrast-enhanced magnetic resonance imaging for evaluation of the effectiveness of high-intensity focused ultrasound for localized prostate cancer. [ABSTRACT FROM AUTHOR]

What's known on the subject? and What does the study add? We have previously shown that percutaneous radiofrequency ablation guided by image-fusion technology allows for precise needle placement with real time ultrasound superimposed with pre-loaded imaging, removing the need for real-time CT or MR guidance. Emerging technology also allows real-time tracking of a treatment needle within an organ in a virtually created 3D format. To our knowledge, this is the first study utilising a sophisticated ultrasound-based navigation system that uses both image-fusion and real-time probe-tracking technologies for in-vivo renal ablative intervention. OBJECTIVES To evaluate the feasibility, accuracy and efficacy of ultrasonography (US)-guided percutaneous radiofrequency ablation (RFA) in the canine kidney model using novel Global Positioning System-like probe tracking technology. [ABSTRACT FROM AUTHOR]

To create a textured virtual model of a real object, the 3D geometric model that is generally measured by a laser scanner must be aligned with the 2D image that is obtained from image sensors excluding some sensors for which geometric and photometric information are obtained at the same time. One conventional registration method that has been proposed compares the contour lines of the silhouette image of the 3D geometric model and of the 2D image and estimates the relative positions of both according to iterative calculations. However, a method that uses point correspondences of contour points in the 2D image and contour points of the silhouette image must find the nearest neighboring points for each iterative calculation, and the computational cost is high. Therefore, in this paper, the authors propose a new registration algorithm of grayscale images and 3D geometric models by using 2D distance maps that are constructed by using the Fast Marching Method from the boundary of an object on the grayscale image. They also show the effectiveness of the proposed method by performing simulation experiments and experiments using actual images. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(14): 52–62, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20634 [ABSTRACT FROM AUTHOR]

In surgical navigation systems, system error analysis is performed because of the need for correct superposition of three-dimensional data obtained with three-dimensional position sensors and different coordinate systems for the images. Lea and colleagues proposed a registration graph for providing a systematic description with a graph of the geometrical position of the system and performing error analysis. However, the registration graph requires the explicit input of errors for each 3D data item. The authors expanded this system to automatically calculate individually occurring errors from system design information through a simulation, and to perform direct error analysis from the system design information. As a result, a user without specialized knowledge of error analysis can automatically perform error analysis by virtually designing a 3D data integration system on a computer. In this paper, the authors constructed a system simulator for modeling point-to-point registration and 3D position sensors, performing automatic error calculation with the simulation based thereon, and designing a system easily using a GUI. Furthermore, as a demonstration of the simulator, the simulator was applied to error analysis for a system including point-to-point registration and 3D position sensors, and its effectiveness and reliability were confirmed. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(8): 45–59, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20377 [ABSTRACT FROM AUTHOR]

Aim/Methods: Diabetic nodular glomerulosclerosis is considered to be the specific renal lesion of diabetes mellitus (DM). However, some cases, in which nodular glomerulosclerosis was found without any manifestation of DM, have also occasionally been reported. We clinicopathologically examined seven cases without a prior history of DM. They consisted of six men and one woman with a mean age of 57 years, and included three cases with family history of DM and six cases with hypertension. Results: Mean body mass index was 26.2 ± 5.9 (means ± SD) kg/m2 and haemoglobin A1c 5.3 ± 1.1% or haemoglobin A1 7.0 ± 0.6%. Mean plasma glucose levels were 5.3 ± 0.7 mmol/L at fasting and 10.1 ± 1.9 mmol/L at 2 h of 75 g OGTT (normal: 1 patient; impaired glucose tolerance: 4 patients; DM: 2 patients). None of them showed diabetic retinopathy in fundoscopic ophthalmoscopy. Mean serum creatinine was 268 ± 215 μmol/L, urinary protein 5.2 ± 4.0 g/day, and three patients had mild haematuria. Renal biopsy revealed typical nodular glomerulosclerosis, a negative deposition based on an immunofluorescence study, and neither any significant electron dense deposits nor fibrils on electron microscopy. Conclusion: These patients at presentation had no overt clinical manifestations of glucose intolerance. Diabetic nodular glomerulosclerosis can occur in patients without overt DM, suggesting the role of factors additional to prolonged hyperglycaemia in the pathogenesis of this disorder. [ABSTRACT FROM AUTHOR]

This paper proposes a camera projection model for an oblique-viewing endoscope, intended for application to an extended virtual reality system. The oblique-viewing endoscope differs from the forward-viewing endoscope by the fact that the view field can be shifted by rotating the scope cylinder. The projection model proposed in this study describes the systematic relation between the rotation angle of the scope cylinder and the external parameters of the camera model. A calibration method is also proposed for estimating the parameters of the projection model, and its accuracy is investigated. The oblique-viewing projection model is derived as an extension of the general pinhole camera model by adding two axes of rotation as parameters and using the angle of rotation of the scope cylinder as the input. In the experiment, an abdominal endoscope is used as the real equipment. A rotary encoder with an angular resolution of 0.25° is used to input the rotation angle of the scope cylinder. The accuracy is examined by the above condition for a scope cylinder rotation angle of 0 to 132°. The average projection error in the proposed model is 2.4 pixels. When the parameters needed in the model are not estimated, the error is increased to 5 to 8 pixels compared to the case in which they are estimated. It is thus shown that the parameters of the proposed model are indispensable in the description of the actual oblique-viewing endoscope. Even if the number of data points for each angle is 2, an accuracy such that the average error is less than 2.8 pixels is obtained. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 88(2): 19–31, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20145 [ABSTRACT FROM AUTHOR]

SUMMARY:To investigate the outcome of aneurysmal subarachnoid haemorrhage (SAH) in patients on maintenance haemodialysis (HD), eight patients on maintenance HD and 245 patients not on HD who suffered from SAH, all of whom were surgically treated at our institution between 1993 and 1997, were reviewed. The clinical features and 3-month outcome of SAH were analysed in the eight HD patients (three males, five females) and compared with those in the 245 non-HD patients (77 males, 168 females). Although there were no significant differences in the patient’s age, gender and pre-operative grading of SAH with the Hunt and Hess grading scale, the mortality rate in HD patients was significantly higher than that in non-HD patients (50% [4/8] vs 13% [32/245]; P < 0.01). It was concluded that the outcome of aneurysmal SAH in HD patients was extremely poor. The explanation for the worse prognosis in HD patients seems not to lie in systemic heparization but in a vulnerability to SAH, because SAH in all HD patients occurred after anticoagulant activity from the previous dialysis had already disappeared. [ABSTRACT FROM AUTHOR]

Objectives To evaluate the effects of transrectal compression of the prostate for intra-operative prostatic swelling and intraprostatic point shift during high-intensity focused ultrasound treatment of localized prostate cancer. Methods Patients treated with whole-gland high-intensity focused ultrasound as primary monotherapy for localized prostate cancer were enrolled in the study. Using the standard and compression method, the volumes of degassed water in the balloon covering the high-intensity focused ultrasound probe were 50 mL and 80-160 mL, respectively. To identify prostatic swelling and shift during high-intensity focused ultrasound and the volume occupied by the non-enhanced area, three-dimensional prostate models were reconstructed using ultrasound and contrast-enhanced magnetic resonance imaging. Results In comparison with the standard ( n = 40) and compression ( n = 48) methods, intraoperative increase in the prostate volume (21% vs 5.3%; P = 0.044), intraprostatic point shift (4 mm vs 2 mm, P = 0.040 in the transition zone; 3 mm vs 0 mm; P = 0.001 in the peripheral zone) and the volume occupied by the non-enhanced area (89% vs 96%; P = 0.001) were significantly suppressed. The biochemical disease-free survival rate in patients treated using the compression method was significantly improved relative to the standard method (92.6% vs 76.5%; P = 0.038). Regarding complications, there was no significant difference in the rate of urethral stricture ( P = 0.9), urinary tract infection ( P = 0.9), incontinence ( P = 0.3), erectile dysfunction ( P = 0.9) or recto-urethral fistula between the patients treated using the standard and compression methods. Conclusions Intraoperative transrectal compression suppresses intraoperative increase in the prostate volume and intraprostatic point shift during high-intensity focused ultrasound, having the potential to achieve precise whole-gland and lesion-targeted focal therapy. [ABSTRACT FROM AUTHOR]