Compton spectroscopy for rotation-mode computed tomography.

In computed tomography (CT) systems, it is desirable to know the X-ray energy spectra for various applications, including medical CT imaging, and diagnostic field and heavy ion therapy. However, because of the restricted space, the only practical solution is to use Compton spectroscopy, where the incident spectrum is inferred from the scattered spectrum. The geometry of the scatterer and its position within the CT can affect the spectrum of the secondary beam, making it difficult to determine the primary spectrum during operation of the CT system. A modified Compton spectrometer is described that allows measurement of the X-ray energy spectra during operation, and most importantly, in rotation mode. The geometry of the scatterer was optimized to reduce the energy broadening of the secondary beam. The performance of the system was evaluated by comparing the reconstructed exposure to that measured directly using an ion chamber.

Atelocollagen-mediated local and systemic applications of myostatin-targeting siRNA increase skeletal muscle mass.

RNA interference (RNAi) offers a novel therapeutic strategy based on the highly specific and efficient silencing of a target gene. Since it relies on small interfering RNAs (siRNAs), a major issue is the delivery of therapeutically active siRNAs into the target tissue/target cells in vivo. For safety reasons, strategies based on vector delivery may be of only limited clinical use. The more desirable approach is to directly apply active siRNAs in vivo. Here, we report the effectiveness of in vivo siRNA delivery into skeletal muscles of normal or diseased mice through nanoparticle formation of chemically unmodified siRNAs with atelocollagen (ATCOL). ATCOL-mediated local application of siRNA targeting myostatin, a negative regulator of skeletal muscle growth, in mouse skeletal muscles or intravenously, caused a marked increase in the muscle mass within a few weeks after application. These results imply that ATCOL-mediated application of siRNAs is a powerful tool for future therapeutic use for diseases including muscular atrophy.

Dissecting insect leg regeneration through RNA interference.

Nymphs of hemimetabolous insects such as cockroaches and crickets exhibit a remarkable capacity for regenerating complex structures from damaged legs. Until recent years, however, approaches to elucidate the molecular mechanisms underlying the leg regeneration process have been lacking. Taking the cricket Gryllus bimaculatus as a model, we found that a phenotype related to regeneration frequently appears during leg regeneration, even though no phenotype is induced by RNA interference (RNAi) in the cricket nymph, designated as regeneration-dependent RNAi. Since then, we have investigated the functions of various genes encoding signaling factors and cellular adhesion proteins like Fat and Dachsous during leg regeneration. In this review, we summarize the classical knowledge about insect leg regeneration and introduce recent advances concerning the signaling cascades required for regenerating a leg. Our results provide clues to the mechanisms of regeneration which are relevant to vertebrate systems.

[Aortic root remodeling and coronary artery bypass grafting for acute type A aortic dissection involving the left main coronary artery; report of a case].

A 56-year-old male was admitted for sudden chest pain followed by loss of consciousness and paraplegia. The electrocardiogram (ECG) revealed ST-elevation in leads II, III, and aVF and ST-depression in leads V3 to V6. The ultrasonic cardiography (UCG) demonstrated an intimal flap in the ascending aorta, grade III aortic regurgitation (AR), and akinesis of the posterior wall of the left ventricle. Transesophageal echocardiography directly showed dissection of the left main coronary artery. Emergency coronary artery bypass grafting (CABG) to the left anterior descending artery (LAD), obtuse marginal artery (OM) and posterolateral artery (PL) was performed using the saphenous vein. In addition, valve-sparing aortic root remodeling was performed in conjunction with replacement of the ascending aorta. The left coronary orifice was repaired and reattached to the prosthetic graft. The patient was weaned from cardiopulmonary bypass without catecholamine support. He was discharged from the hospital on foot after rehabilitation of the paraplegia. AR remains mild by UCG 3 years after surgery.

Preliminary study of using imaging plates to map skin dose of patients in interventional radiology procedures.

A method using europium-doped BaFBr imaging plates (IPs) has been studied for mapping entrance skin doses during interventional radiology (IR); the mapping is useful for detecting overlap between irradiation fields and determining the most exposed skin areas. IPs, which are two-dimensional radiation sensors made of photostimulated luminescence materials, have a linear dose response up to approximately 100 Gy, can accurately measure doses from 1 microGy to 10 Gy and can be used repeatedly. Because the energy dependence of IPs is rather high, the IPs were characterised in this study and a sensitivity variation of approximately 13% was observed for effective energies of 32.7 to 44.7 keV, which are used in IR procedures. Simulation of actual interventional cardiology procedures showed that the variation of sensitivity was within 5%, meaning that IPs are practical for measuring skin doses during IR. Moreover, the patient data can be stored online and easily called up when IR procedures must be repeated, helping to prevent radiation injuries.

The proposal of noninvasive quantitative diagnostic method of the atherosclerosis and the clarification of organ correlation of atherosclerosis and oxygen metabolism.

The proposal of noninvasive diagnostic method of mechanical degradation of vascular wall is clinically useful and it will be correlated with noninvasive diagnostic method of atherosclerosis. Supersonic Doppler effect sensor has been used to measure blood flow velocity as a noninvasive measuring method. However, it is remain problem whether the output from the Doppler effect sensor really detects the pure blood flow velocity. Theoretically, when the Doppler effect sensor is set perpendicular to the blood flow direction, that is, perpendicular to the blood vessel, the output will correspond to the expansion velocity of blood vessel wall, because it detect the frequency of Doppler shifted supersonic scattered from vascular wall. Previously, on the basis of this concept, using Doppler effect sensor, we showed this method can really detect the deformation velocity of blood vessel wall and it correlates the degradation of elastic property of blood vessel. Furthermore, using this proposed measuring method, atherosclerosis is found to progress correspondingly with the visco-elastic degradation of vascular wall. In this paper, on the basis of our proposed method, the quantitative noninvasive estimation method of the degradation of vascular wall and the progressive degree of atherosclerosis by unique parameter has been proposed. Using this method, the degradation of vascular wall is correlated to the oxygen metabolic function of blood vessel corresponding to the function of oxygen transportation and progression of atherosclerosis. Furthermore, the organ correlation on the atherosclerosis between lower limb and carotid is investigated by this proposed method.

Restrictive ventilatory impairment and arterial oxygenation characterize rest and exercise ventilation in patients after fontan operation.

The objective of this study was evaluate the relationships between abnormal pulmonary circulation, lung function, and respiratory response during exercise in Fontan patients. Pulmonary function and cardiopulmonary exercise tests were performed in 101 Fontan patients and 122 controls. A small vital capacity (VC) with a high residual volume-to-total lung capacity ratio and a slight but significant low arterial saturation with hypocapnia were observed in Fontan patients. The number of surgical procedures determined VC. Total cavopulmonary connection, fenestration, higher pulmonary arterial wedge pressure, and smaller VC were independent determinants of low arterial saturation, which was the only determinant of hypocapnia. Arterial saturation decreased during exercise and resting arterial saturation correlated with that at peak exercise. Improvement in dead space ventilation was less in Fontan patients and was independently determined by resting arterial saturation. A steeper minute ventilation-carbon dioxide production slope was determined by resting arterial saturation, arterial carbon dioxide tension, and peak oxygen uptake. In Fontan patients, in addition to dead space ventilation, surgery-related reduced VC, the type of repair, and high pulmonary arterial wedge pressure cause arterial desaturation with subsequent hypocapnia, resulting in accelerated inefficient ventilation at rest and during exercise.

[Resection of freely mobile atheroma in the ascending aorta under circulatory arrest during coronary artery bypass grafting surgery].

A 52-year-old male with a 13 years history of hemodialysis developed unstable angina. Preoperative examination revealed critical stenoses in 3 coronary arteries and extensive calcification in the ascending aorta. During urgent coronary artery bypass surgery, epiaortic ultrasonography demonstrated a large and markedly mobile atheroma in the ascending aorta. Therefore, he underwent resection of this atheroma using cardiopulmonary bypass and circulatory arrest. His postoperative course was fine. This aggressive strategy for a diseased aorta can be a viable option in selected cases. Epiaortic ultrasonography appeared to be indispensable during surgery for patients like a present one.

[Stent-graft implantation for the patient with ruptured acute aortic syndrome: report of a case].

We report a ruptured case of acute aortic syndrome and a successful treatment with transcatheter placed stent-graft. A 67-year-old man underwent a stent-graft implantation for the patient with ruptured acute aortic syndrome. The patient admitted in our institute for a diagnosis of ruptured acute aortic dissection. We planned to operate a graft replacement for distal arch aorta. But he was complicated with right-side monoplesia before the operation. Then we performed a stent-graft implantation in order to avoid the usage of extra-corporeal circulation. The implantation of the stent-graft was successful and shrinkage of the hematoma around the ruptured aorta was documented on the computed tomography of 7 post-operative day.

[Coronary artery aneurysm developed acute myocardial infarction: report of a case].

A 68-year-old woman without angina developed acute antero-septal myocardial infarction. Coronary angiogram revealed saccular coronary artery aneurysm at the origin of the diagonal branch and relatively mild coronary artery stenosis. Emboli from the coronary aneurysm was strongly suggested. We placed coronary bypass grafts onto left anterior descending, diagonal and obtuse marginal branches, and excluded the coronary aneurysm by ligating both its inflow and outflow. The postoperative course was uneventful. There are several treatments of choice for patients with coronary aneurysm. We believe that surgery is mandatory and that exclusion of the coronary aneurysm should be considered in every possible case.

Development of a new passive integral dosemeter for gamma ray monitoring using an imaging plate.

A new passive integral dosemeter for gamma ray monitoring is being developed using an imaging plate (IP). In the application of IPs to dosimetry, a fading effect causes serious problems. The fading is considered to be caused by the recombination or holes and charges trapped shallowly in the F centres, which have several activation energies. Appropriate annealing procedures allow elimination of trapped charges with low activation energies, and quantitative estimation of the radiation dose is possible. The optimum condition for minimising the effect of fading on dose estimation was obtained by post-irradiation annealing of BAS-MS (BAS-MS2025, fabricated by Fuji Film Co. Ltd) IPs at 80 degrees C for 24 h. This was confirmed by calculation. Under this condition, the detection limit was calculated to be 3.15 microSv when 10% error is allowed. A 1-month integral dose was measured by the IP. The results were compared with those obtained using a commercially available fluoro-glass dosemeter.

Severely impaired cardiac autonomic nervous activity after the Fontan operation.

BACKGROUND: Elevated neurohumoral activity and an abnormal cardiopulmonary response to exercise are well-established characteristics in patients after the Fontan operation. However, there have been few studies addressing cardiac autonomic nervous activity (CANA) in these patients. METHODS AND RESULTS: We evaluated CANA in 63 post-Fontan patients and 44 controls. Cardiac parasympathetic nervous activity (PSNA) was estimated by heart rate (HR) changes after cholinergic blockade, HR variability, and arterial baroreflex sensitivity. Cardiac sympathetic nervous activity was estimated by the heart to mediastinum [(123)I]metaiodobenzylguanidine activity ratio (H/M) and the HR increase (DeltaHR) after isoproterenol infusion (beta). DeltaHR and peak oxygen uptake (VO(2)) were measured by exercise test. There was no difference in beta between the Fontan group and controls. PSNA and H/M were markedly lower than in controls (P<0.001). PSNA and beta were related to DeltaHR (P<0.05); however, peak VO(2) was not correlated with DeltaHR. Neither PSNA nor H/M was associated with clinical features, including hemodynamics, type of repair, number of surgical procedures, age at Fontan operation, or follow-up period, and administration of an angiotensin-converting enzyme inhibitor did not improve the impaired CANA in these patients. CONCLUSIONS: After the Fontan procedure, postsynaptic beta-sensitivity is maintained and is important in DeltaHR during exercise as is PSNA, although DeltaHR does not determine exercise capacity. The lack of a relationship between CANA and clinical features implies that, in addition to surgical damage, the Fontan circulation per se may impair CANA. Angiotensin-converting enzyme inhibitor administration does not change this abnormality.

[Diagnosis of prostate capsular invasion by pelvic magnetic resonance imaging and serum level of prostate specific antigen].

Transrectal ultrasonography (TRUS), computed tomography (CT), and magnetic resonance imaging (MRI) are employed to diagnose the clinical stage of prostate cancer. However, several cases are diagnosed as pathological stage pT3 after total prostatectomy. We investigated the accuracy of the evaluation of pathologic capsular penetration by preoperative pelvic MRI and preoperative serum PSA level and capsular penetration. The diagnostic accuracy of capsular penetration by MRI was 63.3%. On the other hand, the diagnostic accuracy of capsular penetration by preoperative PSA was 89.7% when its cut off value was 17 ng/ml. We conclude that preoperative serum PSA level could be more useful to diagnose accurately stage of prostate cancer than pelvic MRI.

[High pressure occlusion of leukocyte depletion arterial line filter in patients with cardio-pulmonary bypass surgery].

Cardio-pulmonary bypass (CPB) leads the activation of neutrophil, which may cause reperfusion organ dysfunction. Utility of using the leukocyte depletion arterial filter to pretend postoperative complications has been reported. The other side, the risk of the leukocyte depletion filter occlusion with high-pressures of CPB arterial line (high-pressure occlusion) has been noted. We used the leukocyte deletion filter (LG-6, Pall), and experienced two cases of high-pressure occlusion in 421 CPB surgery with LG-6 (0.48%). No high-pressure occlusion was occurred with 1,508 patients used the standard arterial line filter in it period (0%, p = 0.007). In the both cases of high-pressure occlusion, monitored arterial line pressure increased to over 340 mmHg within 10 minutes after CPB installation. The filters were changed to standard type, then no more filter trouble was occurred. In the second case, we inspected the occluded LG-6. Light microscopic survey showed eosin stained small spherical cells (HE) and negative for fibrin (PTAH). Electromicroscopy revealed that spherical cells (1-2 microns) adherated to structure of the filter. No fibrin was detected with Gel electrophoresis. Because of the pathologic analysis, the cells, which might cause the filter occlusion, were platelet. In addition, no fibrin exist suggests that the coagulation system did not relate to the high-pressure occlusion. In conclusion, we experienced two high-pressure occlusion cases of the leukocyte depletion arterial filter with CPB surgery (0.48%); the filter occlusion may be caused by the initial thrombus formation by platelet.

Influence of ventricular morphology on aerobic exercise capacity in patients after the Fontan operation.

OBJECTIVES: This study investigated the influences of ventricular morphology, hemodynamics and clinical findings on exercise capacity in patients after the Fontan operation. BACKGROUND: Determinants of exercise capacity after the Fontan operation remain unclear. METHODS: Peak oxygen uptake (PVo2) was determined in 105 patients by exercise test and compared to hemodynamics and clinical findings. Patients were divided into three groups based on ventricular morphology: those with a right ventricle (group RV), a biventricle (group BV) and a left ventricle (group LV). RESULTS: Ten patients with atrioventricular valve regurgitation (AVVR) or hypoxia exhibited a low PVo2. After excluding these patients, although PVo2 did not correlate with hemodynamics, except ventricular ejection fraction (p < 0.02), it correlated with age at the Fontan operation and exercise test (p < 0.002). The PVo2 was higher in group LV (63+/-9%) than in groups RV (55+/-9%) and BV (55+/-12%) (p < 0.01), while an inverse correlation between PVo2 and age at operation was demonstrated only in group RV (p < 0.05). Groups RV or BV and age at exercise test were associated with a lower PVo2, whereas group LV was an independent predictor of a higher PVo2 (p < 0.01). During 4.2 years of follow-up, a decrease in peak heart rate was related to a decrease in PVo2 (p < 0.05). The PVo2 decreased in group RV (p < 0.01). CONCLUSIONS: In addition to AVVR, hypoxia, and heart rate response, ventricular morphology is related to exercise capacity. Early Fontan operation may be beneficial in terms of exercise capacity, especially in the group RV patients.

Sonic hedgehog facilitates dopamine differentiation in the presence of a mesencephalic glial cell line.

The aim of this study was to establish a cellular system to investigate the requirement for cell surface and diffusible molecules in the differentiation of fetal mesencephalic cells toward the dopamine lineage. Toward this end, we immortalized rat embryonic day 14 (E14) mesencephalon with a regulatable retroviral vector encoding v-myc. The stably transduced cells were pooled and designated as VME14 cells. VME14 cells proliferated rapidly, stopped proliferating, extended processes, and expressed GFAP after suppression of the v-myc expression with tetracycline, suggesting that VME14 cells differentiated into glial cells. Dissociated cells derived from the E11 rat mesencephalon gave rise to only a small number of tyrosine hydroxylase (TH)-positive neurons. However, when grown on a monolayer of the differentiated VME14 cells, a significantly higher number of cells differentiated into TH-positive neurons. VME14 cells were transduced with the secreted N-terminal cleavage product of the Sonic hedgehog gene (SHH-N), an inducer of mesencephalic dopaminergic neurons. This monoclonal, SHH-N-overexpressing cell line further enhanced dopaminergic differentiation of E11 rat mesencephalon cells. Thus, SHH-N and signals derived from fetal mesencephalic glia act cooperatively to facilitate dopaminergic differentiation. These fetal mesencephalon-derived cell lines will provide tools for the study of signals involved in dopaminergic differentiation.

[Study of neoadjuvant chemotherapy for invasive bladder cancer with MEC (methotrexate, epirubicin, cisplatin) therapy].

Eighteen patients with locally invasive bladder cancer were treated with 1 or 2 cycles of neoadjuvant chemotherapy consisting of methotrexate, epirubicin and cisplatin (MEC). All patients underwent radical cystectomy and pelvic lymph node dissection. Down-staging was observed in twelve (complete pathological response in 3 and partial pathological response in 9) patients (response rate were 67%). Four of the 18 patients died of disease and all of them had not achieved down-staging. Multivariate analysis revealed nodal status to be the only independent predictor. With regard to side effects, gastrointestinal symptoms and myelo-suppression were observed in almost all patients. Thrombocytopenia was observed in 13 patients (72%) including 7 patients who showed symptoms over grade 3. Gastro-intestinal symptoms and leukocytopenia disappeared with granisetron and granulocyte colony stimulating factor. There were no treatment-related deaths in this study. These results indicate that MEC therapy was safely performed and showed a high response rate in patients with locally invasive bladder cancer.

[Clinical outcome and analysis of radical prostatectomy in clinical stage B and C prostate cancer].

Between 1989 and 1999, 40 patients treated with radical prostatectomy for clinical stage B and C prostate cancer were analyzed. Prostate-specific antigen (PSA) failure after radical prostatectomy occurred in four patients, and one of them died of clinical recurrence of prostate cancer. Cause-specific survival at 5 years was 91.7% and PSA failure-free rate at 5 years was 76.8%. Staging accuracy of CT and MRI image was not satisfactory. In 41.7% patients, extracapsular extension can not be determined. Preoperative serum PSA levels of pathologically organ-confined disease (OCD) patients were significantly lower than those of pathologically non-OCD patients. Further analysis indicated that preoperative serum PSA levels of greater than 20.1 ng/ml are useful predictors for pathologically non-OCD.