A method for bronchoscope tracking by combining a position sensor and image registration.

This paper describes a method for tracking a bronchoscope by combining a position sensor and image registration. A bronchoscopy guidance system is a tool for providing real-time navigation information acquired from pre-operative CT images to a physician during a bronchoscopic examination. In this system, one of the fundamental functions is tracking a bronchoscope's camera motion. Recently, a very small electromagnetic position sensor has become available. It is possible to insert this sensor into a bronchoscope's working channel to obtain the bronchoscope's camera motion. However, the accuracy of its output is inadequate for bronchoscope tracking. The proposed combination of the sensor and image registration between real and virtual bronchoscopic images derived from CT images is quite useful for improving tracking accuracy. Furthermore, this combination has enabled us to achieve a real-time bronchoscope guidance system. We performed evaluation experiments for the proposed method using a rubber phantom model. The experimental results showed that the proposed system allowed the bronchoscope's camera motion to be tracked at 2.5 frames per second.     

Rapid scanning protocol for brain (18)F-FDG PET: a validation study.

Although (18)F-FDG PET is an established technique to assess brain glucose use, a shorter imaging time is preferable for patient convenience and increased throughput. The aim of this study was to validate a brain (18)F-FDG PET protocol more rapid than the conventional protocol. METHODS: For comparison of normalized metabolic activities, brain (18)F-FDG PET was performed on 60 healthy subjects and 25 patients with probable Alzheimer's disease (AD), and an additional 20 healthy subjects served as a control group to assess diagnostic performance between the conventional and rapid scanning protocols. Conventional scans were acquired for a total of 20 min (a 10-min emission and a 10-min transmission). Immediately after conventional scanning, rapid scanning was performed for a total of 4 min (a 3-min emission and a 1-min transmission). PET images were anatomically standardized using NEUROSTAT, with pixel values normalized to the individual global value. Two database sets, from the 2 protocols, were compared by regional values and pixel-by-pixel analysis. A receiver-operating-characteristic analysis was performed for comparison of diagnostic accuracy between the 2 protocols. A kinetic simulation study was also performed to examine the possible difference due to the time lag between the protocols. RESULTS: Although small differences in normalized activity were found in several regions in the healthy subjects between the 2 protocols, no significant difference was found in any region in the patient group. The coefficients of variation of the normalized activity were 20%-30% larger in the rapidly scanned images, but the mean z images and their coefficient-of-variation images did not differ. The kinetic simulation study suggested that the differences were caused by the time lag between the 2 protocols. No significant differences were found in area under the receiver-operating-characteristic curves, and the diagnostic accuracies for the detection of AD were virtually equal between the 2 protocols. CONCLUSION: The rapid scanning protocol used in the present study could provide results nearly equivalent to data from the conventional protocol. Thus, it is feasible to use this rapid protocol to detect AD, without losing diagnostic accuracy.     

A computer-assisted videodensitometric method to visualize mineral distributions in in vitro and in vivo formed root caries lesions

A computer-assisted videodensitometry (CAV) method is presented for the microradiographical mineral determination and mineral visualization of in vitro and in vivo formed dentin lesions. The method employs as essential steps (1) image digitizing by a CCD camera, (2) conversion of gray values to equivalent aluminium thicknesses and (3) conversion of aluminium thickness to vol% of mineral. Procedure and accuracy are described. The CAV method is illustrated for dentin lesions formed in vitro as well as for clinical root caries lesions. The CAV method is especially advantageous for clinical lesions because it can be employed for very complex mineral distributions and irregular lesion outlines. In given areas of interest, the mineral distribution (in vol%) can be plotted in 3D form in pseudo-colors. Conventional micro radio graphical profiles can be obtained directly from the CAV images. For in vitro lesions, the mineral distribution parameters, lesion depth, mineral loss, and mineral acquisition values can be generated from CAV images with a reproducibility of better than 7%. The CAV method is a valuable tool in quantitative mineral studies of clinical lesions in extracted teeth as well as in situ lesion investigations.     

Tumor lysis syndrome at the induction therapy of the first remission in two cases of T-ALL

The anti-tumor therapy followed by tumor lysis syndrome may cause the metabolic disorders including hyperkalemia, hyperphosphatemia and hyperuricemia. It should be known that it occurs frequently in lymphoproliferative diseases, especially in Burkitt's lymphoma. Two cases of T-ALL accompanied by this syndrome, from which the patients were recovered, at the induction therapy of the first complete remission are reported here. Case 1. A 28-year-old man received VP therapy under the diagnosis of T-ALL with massive hepatosplenomegaly and bilateral enlarged kidneys. During the therapy, metabolic disorders with both renal failure and ventricular tachycardia happened. They were resolved by certain series of treatments. The patient was brought to a complete remission with normal size of liver, spleen and kidneys. Case 2. A boy aged 15 having received the intrasubarachnoidal infusion of MTX and 1-Ad-VP therapy under the diagnosis of T-ALL accompanied by this syndrome which was improved by an appropriate treatment, and the patient was lead to the remission. The risk factors of this syndrome, such as 1-high drug sensitivity of the tumor; 2-renal dysfunction; 3-rapid cytokinetics of the tumor cell; 4-bigger size of the tumor, as well as the preventive treatment of this syndrome are reviewed.     

Prognostic factors in idiopathic preretinal macular fibrosis

We retrospectively studied 124 eyes with idiopathic preretinal macular fibrosis to assess the value of fluorescein angiography and vitreous examination for predicting the visual prognosis. During a mean follow-up period of 43 months (range, 12–14 months), the visual acuity of 33 eyes (27%) declined two or more lines from the initial value, although the appearance of the fibrosis remained unchanged in 114 cases (92%). At initial examination, 38 eyes (31%) showed fluorescein leakage into the macula; these eyes were more prone to further visual deterioration than were those without leakage (P< 0.05). Of 14 eyes with partial vitreous detachment and vitreous traction to the fibrosis, 6 (43%) had a final visual acuity of 20/200 or worse; this proportion was significantly higher than that found either in eyes with no detachment or in those with complete vitreous detachment (P< 0.05). The presence of fluorescein leakage and/or vitreous traction to the fibrosis may predict worse functional prognosis in eyes with idiopathic preretinal macular fibrosis.J. Akiba and A. Yoshida were on leave from the Department of Ophthalmology, Asahikawa Medical College, Japan     

Autoradiographic and confocal laser microscopic observation show lafutidine binds to CGRP-immunoreactive nerves as well as gastric parietal cells

The present study was undertaken to observe the binding sites of lafutidine, a newly invented H₂ receptor antagonist ((+/-)-2-(furfurylsulfinyl)-N-[4-[4-(piperidinomethyl)-2-pyridyl]oxy-(Z)-2 butenyl] acetamide), in the Mongolian gerbil and human gastric mucosa using unfixed cryostat section or incubation with aqueous solution of tritiated lafutidine, followed by in vitro autoradiography or autoradiography of soluble compounds. The localization of calcitonin gene-related peptide immunoreactivity was compared with the lafutidine binding sites. As a result, lafutidine-specific binding sites in the body of the fundic glands were accumulated on the parietal cells, while in the neck and base of the fundic glands, lafutidine was found to bind to the CGRP immunoreactive nerves. In the human fundic mucosa, the lafutidine bindings were also observed on the enteric nerves as well as the parietal cells. In conclusion, autoradiographic studies have shown that lafutidine effector sites coincided with the CGRP-immunoreactive nerves as well as the parietal cells.     

A case-control interview study of breast cancer among Japanese A-bomb survivors. II. Interactions with radiation dose

Three breast cancer risk factors were evaluated in terms of their interactions with radiation dose in a case-control interview study of Japanese A-bomb survivors. Cases and controls were matched on age at the time of the hombings and radiation dose, and dose-related risk was estimated from cohort rather than case-control data. Each factor—age at first full-term pregnancy, number of deliveries, and cumulative lactation period summed over births—conformed reasonably well to a multiplicative interaction model with radiation dose (the additive interactive model, in which the absolute excess risk associated with a factor is assumed to be independent of radiation dose, was rejected). An important implication of the finding is that early age at first full-term pregnancy, multiple births, and lengthy cumulative lactation are all protective against radiation-related, as well as baseline, breast cancer. Analyses by age at exposure to radiation suggest that, among women exposed to radiation in childhood or adolescence, a first full-term pregnancy at an early agefollowing exposure may be protective against radiation-related risk.The Radiation Effects Research Foundation (formerly the Atomic Bomb Casualty Commission) was established in April 1975 as a private nonprofit Japanese Foundation, supported equally by the Government of Japan through the Ministry of Health and Welfare, and the Government of the United States through the National Academy of Sciences under contract with the Department of Energy. The present work was performed as part of a collaboration between RERF and the US National Cancer Institute.     

Ion permeation and selectivity of squid axon sodium channels modified by tetramethrin

The pyrethroid tetramethrin greatly prolongs the sodium current during step depolarization and the sodium tail current associated with step repolarization of the squid axon membrane. Non-linear current-voltage relationships for the sodium tail current were analyzed to assess the open sodium channel properties which included the permeation of various cations, calcium block and cation selectivity. Tetramethrin had no effect on any of these properties. It was concluded that tetramethrin modifies the sodium channel gating machinery without affecting the pore properties.     

Klotho reduces apoptosis in experimental ischaemic acute renal failure.

BACKGROUND: Klotho is associated with the suppression of several ageing phenotypes. Because high klotho gene expression was detected in the kidney and several studies have found altered expression in animal models, we explored the physiological relevance of klotho expression in the kidney under renal ischemia reperfusion injury (IRI). METHODS: Male Wistar rats were subjected to bilateral renal ischemia or sham operation, followed by reperfusion for 6, 12 or 24 h, or 2 to 10 days. Renal expression of klotho was assessed by real-time PCR or Western blotting. Creatinine levels were determined. Immunohistochemical studies and TUNEL staining were performed. An adenovirus harbouring the mouse klotho gene (ad-kl) was intravenously administered to one group of rats before renal IRI. RESULTS: Renal klotho mRNA and protein expressions were significantly reduced in IRI rats the first day after ischemia. Pre-treatment with ad-kl resulted in a robust induction of klotho mRNA and protein in the liver but not in the kidney. Ad-kl gene transfer improved serum creatinine and the histological changes. Apoptosis induced by IRI was attenuated following ad-kl administration. CONCLUSION: The data suggest klotho to be involved in the pathophysiology of IRI. Downregulation of renal klotho exacerbates ischaemic acute renal failure, and klotho gene induction has therapeutic potential in managing ischaemic renal damage.