Content-based image retrieval for the diagnosis of myocardial perfusion imaging using a deep convolutional autoencoder

BACKGROUND

Single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) plays a crucial role in the optimal treatment strategy for patients with coronary heart disease. We tested the feasibility of feature extraction from MPI using a deep convolutional autoencoder (CAE) model.

METHODS

Eight hundred and forty-three pairs of stress and rest myocardial perfusion images were collected from consecutive patients who underwent cardiac scintigraphy in our hospital between December 2019 and February 2022. We trained a CAE model to reproduce the input paired image data, so as the encoder to output a 256-dimensional feature vector. The extracted feature vectors were further dimensionally reduced via principal component analysis (PCA) for data visualization. Content-based image retrieval (CBIR) was performed based on the cosine similarity of the feature vectors between the query and reference images. The agreement of the radiologist's finding between the query and retrieved MPI was evaluated using binary accuracy, precision, recall, and F1-score.

RESULTS

A three-dimensional scatter plot with PCA revealed that feature vectors retained clinical information such as percent summed difference score, presence of ischemia, and the location of scar reported by radiologists. When CBIR was used as a similarity-based diagnostic tool, the binary accuracy was 81.0%.

CONCLUSION

The results indicated the utility of unsupervised feature learning for CBIR in MPI.

Bepridil monotherapy failed to prevent coronary vasospasm in a Brugada syndrome patient

Coronary vasospasm sometimes coexists with Brugada syndrome (BrS) and is reportedly associated with poor prognosis. Although calcium channel blockers are considered first-line drugs to prevent coronary vasospasm, they also have the potential to induce ST elevation and ventricular fibrillation (VF) in BrS. Therefore, the optimal medication for such a complicated case is still underdetermined. We report a male patient who presented with VF due to BrS, which was later found to have coexisted with coronary vasospasm. He was treated with low-dose bepridil expecting both its anti-arrhythmic and vasodilatory effects, but a later acetylcholine provocation test showed no suppression of vasospasm. Based on these results, we decided to add nitrates to the medication. This case report illustrates that drug selection needs caution in BrS when complicated with vasospastic angina and that bepridil monotherapy may not be sufficient to suppress coronary vasospasm in such cases.

Three-Dimensional Reconstruction of Pacemaker Lead Trajectory From Orthogonal Chest X-Rays: A Proof of Concept

Understanding the lead trajectory is important in preventing complications after cardiac rhythm device implantation. In this report, we sought to reconstruct the three-dimensional (3D) shape of a pacing lead from radiographs taken at 90-degree angles. All image data were obtained from a 65-year-old male patient, who underwent pacemaker implantation at our hospital due to third-degree atrioventricular block in 2016. Both frontal and lateral chest X-rays were taken just after the device implantation (supine position) and on the post-procedural day 1 (upright position), respectively. Fluorine-18-fluorodeoxyglucose positron emission tomography/CT was performed 75 days after the pacemaker implantation for the diagnosis of cardiac sarcoidosis. Contours of the ventricular leads were manually traced in each X-ray image and saved as Scalable Vector Format (SVG) files using the GNU Image Manipulation Program (GIMP). The 3D reconstruction was performed on Blender 2.93, which is an open-source computer graphics software. The lead trajectory could be reconstructed from bidirectional radiographs, which may allow for further investigation of the 3D shape change of the pacemaker leads.

Image similarity-based cardiac rhythm device identification from X-rays using feature point matching

AIMS

Identifying the manufacturer and the type of cardiac implantable electronic devices (CIEDs) is important in emergent clinical settings. Recent studies have illustrated that artificial neural network models can successfully recognize CIEDs from chest X-ray images. However, all existing methods require a vast amount of medical data to train the classification model. Here, we have proposed a novel method to retrieve an identical CIED image from an image database by employing the feature point matching algorithm.

METHODS AND RESULTS

A total of 653 unique X-ray images from 456 patients who visited our pacemaker clinic between April 2012 and August 2020 were collected. The device images were manually square-shaped, and was thereafter resized to 224 × 224 pixels. A scale-invariant feature transform (SIFT) algorithm was used to extract the keypoints from the query image and reference images. Paired feature points were selected via brute-force matching, and the average Euclidean distance was calculated. The image with the shortest average distance was defined as the most similar image. The classification performance was indicated by accuracy, precision, recall, and F1-score for detecting the manufacturers and model groups, respectively. The average accuracy, precision, recall, and F-1 score for the manufacturer classification were 97.0%, 0.97, 0.96, and 0.96, respectively. For the model classification task, the average accuracy, precision, recall, and F-1 score were 93.2%, 0.94, 0.92, and 0.93, respectively, all of which were higher than those of the previously reported machine learning models.

CONCLUSION

Feature point matching is useful for identifying CIEDs from X-ray images.

P251 Right ventricular free wall dissection clearly detected and recorded by echocardiography: a fatal complication after inferior myocardial infarction

An 81-year-old man was transferred to our institution by ambulance because of poor feeding, general fatigue and slight disorientation lasting for a week. On arrival, he was awake and able to speak, however, his blood pressure was low at 61/43 mmHg in spite of his medical history of hypertension. His ECG showed abnormal Q waves and ST elevation in II, III, aVF leads. The echo exam detected severe hypokinesis in the left ventricular inferior wall and reduced ejection fraction at 30%. Pericardial effusion was not observed in the first echo exam. The patient was diagnosed as cardiogenic shock due to recent inferior myocardial infarction. Coronary angiography was performed, which detected total occlusion of mid right coronary artery, followed by a successful percutaneous coronary intervention (PCI) with a drug-eluting stent under the support of intra-aortic balloon pumping. Nevertheless, his blood pressure remained low and intravenous adrenaline administration was necessary during and even after PCI. To detect the cause of prolonged low blood pressure, echo was performed again immediately after PCI. The echo exam detected new findings: right ventricular posterior free wall was dissected and abnormal shunt flows were obviously observed from left ventricle to right atrium through the dissection cavity during systole. An urgent surgical repair was considered as the only option for his survival, however, his family did not accept it because the operation itself was too risky. On the next day of his admission, he passed away. Right ventricular free wall dissection is a very rare but fatal complication after inferior myocardial infarction, nevertheless, we could detect it by echocardiography with clearly recorded images.

Abstract P251 Figure.

P1386 A change in left ventricular global longitudinal strain is a prognostic indicator in congestive heart failure patients with preserved ejection fraction

Purposes

We examined how changes in left ventricular (LV) global longitudinal strain (GLS) were associated with prognosis in patients with preserved LV ejection fraction (LVEF) after congestive heart failure (HF) admission.

Methods

We studied 123 consecutive patients (age 70 ± 15 years, 55% male) who had been hospitalized due to congestive HF with preserved LVEF (> 50%). The exclusion criteria were atrial fibrillation and inadequate echo image quality for strain analyses. The patients underwent speckle-tracking echocardiography and measurement of plasma NT-ProBNP levels on the same day at the time of hospital admission as well as in the stable condition after discharge. Differences in GLS, LVEF and NT-ProBNP (delta GLS, LVEF and NT-ProBNP ; 2nd – 1st measurements) were calculated. The study end points were all-cause mortality and cardiac events.

Results

Mean periods of echo performance after hospitalization were 2 ±１days (1st echo) and 240 ± 289 days (2nd echo), respectively. During the follow-up (974 ± 626 days), 12 patients died and 25 patients were hospitalized because of HF worsening. In multivariate analysis, delta GLS and follow-up GLS were prognostic factors, whereas baseline and follow-up LVEF, NT-ProBNP, changes in LVEF and NT-ProBNP could not predict cardiac events. Delta GLS (p = 0.002) turned out to be the best independent prognosticator. Receiver operating characteristics analysis revealed that -0.6% of delta GLS was the optimal cut-off value to predict cardiac events and mortality (sensitivity 76%, specificity 67%, AUC 0.75). Kaplan-Meier analysis showed that patients with delta GLS more than -0.6% experienced significantly less cardiac events during the follow-up period (p < 0.0001, log-rank).

Conclusion

A change in LV GLS after congestive HF admission was a predictor of the prognosis in patients with preserved LVEF. It would be useful to check the changes in GLS in those with preserved LVEF after discharge.

P6005Incidence and clinical characteristics of coronary artery spasm in patients with out-of-hospital cardiac arrest

Background

Substantial cases of out-of-hospital cardiac arrest (OHCA) due to acute coronary syndrome have been recognized thus far, but there have been few reports about the aetiology of patients with OHCA without the organic heart disease. Especially, coronary artery spasm would be one of the causes of OHCA.

Purpose

This study aimed to investigate causes of OHCA without the organic heart disease and to investigate the characteristics and angiographic findings of OHCA patients with vasospastic angina (VSA).

Methods

Between January 2010 and April 2018, 920 patients with OHCA caused by probable or definite cardiovascular disease were transferred to our hospital. Return of spontaneous contraction was successfully achieved in 151 patients, among whom diagnosis was made in 130 patients. First, we analysed the causes of OHCA in these patients. Second, we compared clinical and angiographic characteristics between the VSA group with OHCA (OHCA-VSA) and the VSA group without OHCA (stable VSA; n=72) from our database.

Results

Among the 130 patients, 95 (73%) had the organic heart disease; 72, acute coronary syndrome; 19, myocardial disease; 2, valvular heart disease; and 1, congenital heart disease. There were 35 patients (27%) without the organic heart disease. Nineteen patients had primary (i.e., Brugada syndrome, QT prolongation) or secondary arrhythmia (i.e. drug adverse effect). Electrocardiogram, coronary angiogram, and LV structure and function were normal in 35 patients. However, there were 16 patients (11%) with VSA defined by Japanese guideline. The OHCA-VSA group was significantly younger (50±14) than the stable VSA group (64±11, P=0.003). The incidence of diffuse-type spasm in the OHCA-VSA group (100%) was significantly higher than that in the stable VSA group (100% vs. 69%, P<0.05). In addition, the incidence of triple-vessel coronary spasm in the OHCA-VSA group was significantly higher than that in the stable VSA group (86% vs. 25%, P=0.003).

Conclusion

OHCA patients without the organic heart disease had considerable cases of VSA, in addition to primary or secondary arrhythmia. Furthermore, the severity of spasm in the OHCA-VSA group was more serious and extensive than in comparison with the stable VSA group.

P986Future risk of bradyarrhythmias in patients with hypertrophic cardiomyopathy and implantable cardioverter defibrillator indication

Background

Subcutaneous-implantable cardioverter defibrillator (S-ICD) has been shown to be effective for prevention of sudden cardiac death. Patients with hypertrophic cardiomyopathy (HCM) having ICD indication are considered to introduce either S-ICD or transvenous-ICD, however it is uncertain which is better since S-ICD is not suitable for patients who need pacing and data on the necessity for pacing in HCM patients are limited.

Purpose

The purpose of this study was to investigate the risk factors associated with the future risk of bradyarrhythmias needed to be paced in patients with HCM and ICD indication.

Methods

This is a retrospective, single-center cohort study. Of 169 HCM patients diagnosed in our institution, 80 with ICD indication in accordance with the Japanese guideline in 2011 were enrolled as study subjects (31 females, mean age 63±15 years). They were divided into two groups – patients who progressed to bradyarrhythmias which needed pacing during the follow-up period (Brady group) and those who not (Non-brady group). Baseline characteristics at the time of diagnosis of HCM including demographic information, the results of clinical examination such as blood test, echocardiography and electrocardiography (ECG) were compared between the Brady and Non-brady group.

Results

During a mean follow-up period of 6.8±5.4 years, 9 patients (11%) progressed bradyarrhtyhmias which needed pacing. Symptomatic sick sinus syndrome (SSS) was the primary cause (7 SSS, 1 atrial fibrillation [AF] with bradycardia, 1 after atrioventricular nodal ablation). Comparing between the Brady and Non-brady group, there was no significant difference in clinical variables such as age, heart rate, PR interval and QRS duration in ECG, EF levels, BNP levels, beta-blocker usage rate, prevalence of hypertension or diabetes mellitus. On the other hand, women were more in Brady group than in Non-brady group (7/9, 78% vs. 24/71, 34%; p=0.01). Furthermore, more patients in Brady group had documented AF at the beginning and during follow-up period (7/9, 78% vs. 25/71, 36%; p=0.02) and took anti-arrhythmic drugs (AAD) (8/9, 89% vs. 19/71, 27%; p<0.001) including amiodarone than those in Non-brady group.

Conclusion

In HCM patients with ICD indication, around 10% of patients have a potential risk of bradyarrhythmias needed to be paced, especially in female, those with AF and/or AAD usage.

Clinical Assay of Serum SCC-Ag in Urothelial Cancers

Serum squamous cell carcinoma related antigen (SCC-Ag) values were determined in 86 patients with urothelial cancers. Mean + standard deviation for serum SCC-Ag. was 3.4 ± 0.98 ng/ml and positive values (> 2.0 ng/ml) were found in 27%. Neither pathological stage nor cell grade of the urothelial cancer showed any relation to serum SCC-Ag. Serum SCC-Ag. changed parallel to the clinical course. These results suggest that, as there is no specific tumor marker in urothelial cancer, serum SCC-Ag. may be a useful aid in diagnosing cancer and monitoring these patients. Used together with another non-specific marker, an increase in the accuracy of diagnosis of these malignancies can be expected.

Isolated Left Atrial Infective Mural Endocarditis

A 52-year-old man presented with a fever and malaise. Transthoracic echocardiogram was performed because of a holosystolic murmur, which showed mitral valve prolapse and a regurgitation jet toward the posterior wall of the left atrium. There was no apparent vegetation at any valves. Blood cultures were positive for Streptococcus mitis/oralis. Transesophageal echocardiogram revealed vegetation only at the posterior wall of the left atrium exposed to the mitral regurgitant jet. We diagnosed this condition as infective mural endocarditis. This case highlighted the need for a detailed observation of the valves and the atrial wall when infective endocarditis is suspected.

Beneficial effects of adaptive servo-ventilation therapy on readmission and medical costs in patients with chronic heart failure

Adaptive servo-ventilation (ASV) therapy is a novel modality of noninvasive positive pressure ventilation and is now widely utilized to treat patients with chronic heart failure (CHF). However, there has been no clinical study of the effect of ASV therapy on readmission and cost-effectiveness for the treatment of CHF. The present study was conducted to evaluate the clinical efficacy and cost-effectiveness of home ASV therapy in 45 patients with a history of two or more admissions a year for worsening CHF. Seven patients refused to undergo chronic ASV therapy and three died. Thus, 35 patients were eventually enrolled in the present study. New York Heart Association class (2.8 ± 0.4 versus 2.3 ± 0.5, p < 0.001), log plasma B-type natriuretic peptide level (2.53 ± 0.44 versus 2.29 ± 0.40 pg/mL, p < 0.0001), left atrial dimension (47.5 ± 7.0 versus 44.9 ± 7.6 mm, p = 0.014), and mitral regurgitation area ratio (20.3 ± 12.1 versus 16.9 ± 8.9%, p = 0.007) decreased significantly after 12 months of ASV therapy. The frequency of hospitalization after ASV was significantly lower than before ASV (1.0 ± 1.0 versus 2.3 ± 0.5 times/year/patient, p < 0.0001). ASV also decreased the duration of hospitalization from 64.4 ± 46.5 to 22.8 ± 27.5 days/year/patient (p < 0.0001). Consequently, the total medical costs were reduced by 37% after ASV (1.95 ± 1.37 versus 3.11 ± 1.75 million yen/patient, p = 0.003). ASV therapy reduced readmissions and medical costs in patients with CHF.

Favorable effects of early tolvaptan administration in very elderly patients after repeat hospitalizations for acute decompensated heart failure

Tolvaptan (TLV) is an oral selective vasopressin 2 receptor antagonist that acts on the distal nephrons, causing a loss of electrolyte-free water. To date, its early administration in very elderly patients after repeat hospitalizations for acute decompensated heart failure (ADHF) despite receiving optimal medical therapy has not been evaluated. Fifty-six ADHF patients who were >80 years old and had been repeatedly hospitalized were retrospectively enrolled in this study. Twenty-five patients (14 men; mean age 86.7 ± 5.3 years; control group) received standard therapy and 31 patients (15 men; mean age 85.5 ± 4.5 years; TLV group) received oral TLV within 24 h of admission. The rate of worsening renal function was significantly lower in the TLV group than in the control group (13 vs. 40%, P < 0.05). The duration of the return to body weight at a steady state was significantly shorter in the TLV group (5.3 ± 2.8 days) than in the control group (13.9 ± 9.2 days, P < 0.01). Consequently, the hospitalization period in the TLV group (13.5 ± 5.9 days) was significantly shorter than that in the control group (24.7 ± 12.3 days, P < 0.01). In conclusion, the early administration of TLV to very elderly patients who underwent repeat hospitalizations for ADHF resulted in immediate decongestion and thus reduced the hospitalization period with a lower incidence of worsening renal function.

Gamma geometry dependency of efficiency functions in the 4πβ-γ coincidence measurements of complex decaying nuclides

In order to clarify the γ-efficiency dependency of 4πβ-γ efficiency functions, a series of 4πβ-γ efficiency extrapolation measurements of a (134)Cs source were carried out for a wide variety of γ-geometries using a 4πβ(PS)-4πγ detector configuration. As the source is situated in the plastic scintillator (PS) β-detector, the γ-efficiency of the system can be readily changed by extracting the β-detector from the well-hole in a series of stages. For data acquisition and analyses, a list-mode two-parameter data acquisition system was employed. The forms of the extrapolation curves were monitored with decreasing γ-geometry, eventually exhibiting a similar behavior to those obtained in a usual 4πβ-γ coincidence counting system. The experimental results and considerations suggested that the γ-geometry dependency of the efficiency functions were due to summing effects in the γ-channel, and some qualitative remarks on the form of the extrapolation functions are given.

Response of Ge photon detectors to beta-rays and possible reduction of photopeak areas due to beta-gamma coincidence summing effects

In the use of photon detectors having sensitivity to β-rays or internal conversion electrons (CEs), β-γ and/or X-CE coincidence summing may arise. In particular, an n-type germanium detector has a thin dead layer and window, causing considerably higher sensitivity to β-rays and/or CEs especially when sources are located at a small source-to-detector distance. In the present research, reduction of the photopeak area due to β-γ or X-CE coincidence summing has been studied for three germanium detectors.

Absorption and backscatter of internal conversion electrons in the measurements of surface contamination of ¹³⁷Cs

We measured 4π and 2π counting efficiencies for internal conversion electrons (ICEs), gross β-particles and also β-rays alone with various source conditions regarding absorber and backing foil thickness using e-X coincidence technique. Dominant differences regarding the penetration, attenuation and backscattering properties among ICEs and β-rays were revealed. Although the abundance of internal conversion electrons of (137)Cs-(137)Ba is only 9.35%, 60% of gross counts may be attributed to ICEs in worse source conditions. This information will be useful for radionuclide metrology and for surface contamination monitoring.

Ras-related C3 botulinum toxin substrate 1 (RAC1) regulates glucose-stimulated insulin secretion via modulation of F-actin

AIMS/HYPOTHESIS

The small G-protein ras-related C3 botulinum toxin substrate 1 (RAC1) plays various roles in mammalian cells, such as in the regulation of cytoskeletal organisation, cell adhesion, migration and morphological changes. The present study examines the effects of RAC1 ablation on pancreatic beta cell function.

METHODS

Isolated islets from pancreatic beta cell-specific Rac1-knockout (betaRac1(-/-)) mice and RAC1 knockdown INS-1 insulinoma cells treated with small interfering RNA were used to investigate insulin secretion and cytoskeletal organisation in pancreatic beta cells.

RESULTS

BetaRac1(-/-) mice showed decreased glucose-stimulated insulin secretion, while there were no apparent differences in islet morphology. Isolated islets from the mice had blunted insulin secretion in response to high glucose levels. In RAC1 knockdown INS-1 cells, insulin secretion was also decreased in response to high glucose levels, consistent with the phenotype of betaRac1(-/-) mice. Even under high glucose levels, RAC1 knockdown INS-1 cells remained intact with F-actin, which inhibits the recruitment of the insulin granules, resulting in an inhibition of insulin secretion.

CONCLUSIONS/INTERPRETATION

In RAC1-deficient pancreatic beta cells, F-actin acts as a barrier for insulin granules and reduces glucose-stimulated insulin secretion.

N = 16 spherical shell closure in 24O

The unbound excited states of the neutron drip-line isotope 24O have been investigated via the 24O(p,p')23O + n reaction in inverse kinematics at a beam energy of 62  MeV/nucleon. The decay energy spectrum of 24O* was reconstructed from the momenta of 23O and the neutron. The spin parity of the first excited state, observed at E(x) = 4.65±0.14  MeV, was determined to be J(π) = 2+ from the angular distribution of the cross section. Higher-lying states were also observed. The quadrupole transition parameter β2 of the 2(1)+ state was deduced, for the first time, to be 0.15±0.04. The relatively high excitation energy and small β2 value are indicative of the N = 16 shell closure in 24O.

Long-Term (>10 Years) clinical outcomes of first-in-human biodegradable poly-l-lactic acid coronary stents: Igaki-Tamai stents

BACKGROUND

The purpose of this study was to evaluate the long-term safety of the Igaki-Tamai stent, the first-in-human fully biodegradable coronary stent made of poly-l-lactic acid.

METHODS AND RESULTS

Between September 1998 and April 2000, 50 patients with 63 lesions were treated electively with 84 Igaki-Tamai stents. Overall clinical follow-up (>10 years) of major adverse cardiac events and rates of scaffold thrombosis was analyzed together with the results of angiography and intravascular ultrasound. Major adverse cardiac events included all-cause death, nonfatal myocardial infarction, and target lesion revascularization/target vessel revascularization. During the overall clinical follow-up period (121 ± 17 months), 2 patients were lost to follow-up. There were 1 cardiac death, 6 noncardiac deaths, and 4 myocardial infarctions. Survival rates free of all-cause death, cardiac death, and major adverse cardiac events at 10 years were 87%, 98%, and 50%, respectively. The cumulative rates of target lesion revascularization (target vessel revascularization) were 16% (16%) at 1 year, 18% (22%) at 5 years, and 28% (38%) at 10 years. Two definite scaffold thromboses (1 subacute, 1 very late) were recorded. The latter case was related to a sirolimus-eluting stent, which was implanted for a lesion proximal to an Igaki-Tamai stent. From the analysis of intravascular ultrasound data, the stent struts mostly disappeared within 3 years. The external elastic membrane area and stent area did not change.

CONCLUSION

Acceptable major adverse cardiac events and scaffold thrombosis rates without stent recoil and vessel remodeling suggested the long-term safety of the Igaki-Tamai stent.

A simple and versatile data acquisition system for software coincidence and pulse-height discrimination in 4πβ-γ coincidence experiments

A simple but versatile data acquisition system for software coincidence experiments is described, in which any time stamping and live time controller are not provided. Signals from β- and γ-channels are fed to separately two fast ADCs (16 bits, 25 MHz clock maximum) via variable delay circuits and pulse-height stretchers, and also to pulse-height discriminators. The discriminating level was set to just above the electronic noise. Two ADCs were controlled with a common clock signal, and triggered simultaneously by the logic OR pulses from both discriminators. Paired digital signals for each sampling were sent to buffer memories connected to main PC with a FIFO (First-In, First-Out) pipe via USB. After data acquisition in list mode, various processing including pulse-height analyses was performed using MS-Excel (version 2007 and later). The usefulness of this system was demonstrated for 4πβ(PS)-4πγ coincidence measurements of (60)Co, (134)Cs and (152)Eu. Possibilities of other extended applications will be touched upon.

Structural evolution in the neutron-rich nuclei ¹⁰⁶Zr and ¹⁰⁸Zr

The low-lying states in ¹⁰⁶Zr and ¹⁰⁸Zr have been investigated by means of β-γ and isomer spectroscopy at the radioactive isotope beam factory (RIBF), respectively. A new isomer with a half-life of 620 ± 150 ns has been identified in ¹⁰⁸Zr. For the sequence of even-even Zr isotopes, the excitation energies of the first 2⁺ states reach a minimum at N = 64 and gradually increase as the neutron number increases up to N = 68, suggesting a deformed subshell closure at N = 64. The deformed ground state of ¹⁰⁸Zr indicates that a spherical subshell gap predicted at N = 70 is not large enough to change the ground state of ¹⁰⁸Zr to the spherical shape. The possibility of a tetrahedral shape isomer in ¹⁰⁸Zr is also discussed.

β-decay half-lives of very neutron-rich Kr to Tc isotopes on the boundary of the r-process path: an indication of fast r-matter flow

The β-decay half-lives of 38 neutron-rich isotopes from (36)Kr to (43)Tc have been measured; the half-lives of (100)Kr, (103-105)Sr, (106-108)Y, (108-110)Zr, (111,112)Nb, (112-115)Mo, and (116,117)Tc are reported here. The results when compared with previous standard models indicate an overestimation in the predicted half-lives by a factor of 2 or more in the A≈110 region. A revised model based on the second generation gross theory of β decay better predicts the measured half-lives and suggests a more rapid flow of the rapid neutron-capture process (r-matter flow) through this region than previously predicted.

A multichannel time-of-flight system for observation of energetic ions of multispecies generated from relativistic laser plasma

A multichannel time-of-flight (TOF) system was constructed to observe the ions generated from relativistic laser plasma, where the ions have polychromatic energies and multiple species. The TOF system is composed of a ten-channel scintillation detector array and an electromagnet that generates a magnetic field of 0-1.24 T. The magnet field enables us to analyze protons, deuterons, and full-stripped carbon ions to 50, 25, and 150 MeV, respectively. The system experimentally identified protons of 0.27-1.6 MeV energy and ions of a half specific charge (deuterons of 0.3-0.8 MeV and full-stripped carbons of 1.8-4.8 MeV). The measured TOF values agree well with the calculated values within the designed accuracy; +/-2.5 ns for protons and +/-5 ns for the others (d or C(6+)) on each detector channel. Comparison of ion numbers detected by a track detector (CR-39) and the TOF system enabled us to obtain the number of ions detected on each scintillation counter with less than 16% error.

Halo structure of the island of inversion nucleus 31Ne

The cross sections for single-neutron removal from the very neutron-rich nucleus 31Ne on Pb and C targets have been measured at 230 MeV/nucleon using the RIBF facility at RIKEN. The deduced large Coulomb breakup cross section of 540(70) mb is indicative of a soft E1 excitation. Comparison with direct-breakup model calculations suggests that the valence neutron of 31Ne occupies a low-l orbital (most probably 2p(3/2)) with a small separation energy (S(n) approximately < 0.8 MeV), instead of being predominantly in the 1f(7/2) orbital as expected from the conventional shell ordering. These findings suggest that 31Ne is the heaviest halo system known.

[Pulseless arrest in an elderly patient treated with intravenous tissue plasminogen activator for cardioembolic ischemic stroke]

A 77-year-old woman, who had a history of rheumatic mitral stenosis with atrial fibrillation (AF), was referred and admitted to our hospital because of a transient ischemic attack at 4: 55 p.m.. She had taken warfarin for over 10 years, but her condition was not well controlled on admission. At 8: 30 p.m., she had acute ischemic stroke with right facial palsy, right hemiparesis and slurred speech. At 10: 35 p.m., she was treated with intravenous tissue plasminogen activator (t-PA) and her neurological deficits almost fully recovered by 0: 05 a.m. (90 min after t-PA started). At 0: 08 a.m., she collapsed due to sudden pulseless arrest. Using advanced life support, she soon recovered with no complications. After mitral valve replacement and left atrial appendectomy, she was discharged with a modified Rankin scale 0 at day 40. To the best of our knowledge, this is the first case report showing pulseless arrest immediately after treatment with t-PA in an elderly patient with ischemic stroke. Left insular injury seemed to be a crucial mechanism of pulseless arrest in this case.

Spectroscopy of 32Ne and the "Island of Inversion"

We report on the first spectroscopic study of the N=22 nucleus 32Ne at the newly completed RIKEN Radioactive Ion Beam Factory. A single gamma-ray line with an energy of 722(9) keV was observed in both inelastic scattering of a 226 MeV/u 32Ne beam on a carbon target and proton removal from 33Na at 245 MeV/u. This transition is assigned to the deexcitation of the first Jpi=2+ state in 32Ne to the 0+ ground state. Interpreted through comparison with state-of-the-art shell-model calculations, the low excitation energy demonstrates that the "island of inversion" extends to at least N=22 for the Ne isotopes.

Citicoline enhances frontal lobe bioenergetics as measured by phosphorus magnetic resonance spectroscopy

Citicoline supplementation has been used to ameliorate memory disturbances in older people and those with Alzheimer's disease. This study used MRS to characterize the effects of citicoline on high-energy phosphate metabolites and constituents of membrane synthesis in the frontal lobe. Phosphorus ((31)P) metabolite data were acquired using a three-dimensional chemical-shift imaging protocol at 4 T from 16 healthy men and women (mean +/- SD age 47.3 +/- 5.4 years) who orally self-administered 500 mg or 2000 mg Cognizin Citicoline (Kyowa Hakko Kogyo Co., Ltd, Ibaraki, Japan) for 6 weeks. Individual (31)P metabolites were quantified in the frontal lobe (anterior cingulate cortex) and a comparison region (parieto-occipital cortex). Significant increases in phosphocreatine (+7%), beta-nucleoside triphosphates (largely ATP in brain, +14%) and the ratio of phosphocreatine to inorganic phosphate (+32%), as well as significant changes in membrane phospholipids, were observed in the anterior cingulate cortex after 6 weeks of citicoline treatment. These treatment-related alterations in phosphorus metabolites were not only regionally specific, but tended to be of greater magnitude in subjects who received the lower dose. These data show that citicoline improves frontal lobe bioenergetics and alters phospholipid membrane turnover. Citicoline supplementation may therefore help to mitigate cognitive declines associated with aging by increasing energy reserves and utilization, as well as increasing the amount of essential phospholipid membrane components needed to synthesize and maintain cell membranes.

[Long term outcome of arterial switch surgery for transposition of the great arteries: evaluation of the reconstruction of the pulmonary artery]

We assessed the effect of reconstructing the pulmonary artery during arterial switch surgery for transposition of the great arteries on late pulmonary stenosis. Sixty-five patients who underwent Lecompte procedure between September 1991 and December 2006 were divided, by the procedure used chronologically to reconstruct the pulmonary artery, into group XP (single pantaloon patch with equine pericardium, n = 11), group P (direct reconstruction, n = 47), and group AP (single pantaloon patch with fresh autopericardium, n = 7). Outcome and pulmonary stenosis on the most recent ultrasound cardiography (UCG) were compared in the 3 groups. The median follow-up was 13, 7.5, and 1.3 years, respectively. Both early and late mortalities were 1.5% (1/65). Although percutaneous trans-pulmonary angioplasty was necessary in 1, 13, and 3 patients, there was 1, 1, and 0 reoperation for pulmonary stenosis in the 3 groups, respectively. Pulmonary stenosis (pulmonary arterial maximum flow velocity > 3 m/sec on UCG) was present in 4 (40%). 14 (30%). and 3 patients (43%). Although there was no significant difference among the 3 procedures in preventing pulmonary stenosis 10 years after arterial switch surgery, direct reconstruction of the pulmonary artery may show a superior outcome, in particular, over 10 years after arterial switch surgery.

Aberrations of the p14(ARF) and p16(INK4a) genes in renal cell carcinomas

The INK4a / ARF locus on chromosome 9p21, which encodes two distinct genes, p14(ARF) and p16(INK4a), is frequently altered in human neoplasms. To investigate the potential roles of p14(ARF) and p16(INK4a) genes in human renal cell carcinomas (RCCs), we analyzed 6 human RCC cell lines and 91 primary RCCs for homozygous deletion, promoter hypermethylation and expression of the p14(ARF) and p16(INK4a) gene products using differential PCR, methylation-specific PCR, and immunohistochemistry, respectively. Five cell lines showed homozygous co-deletion of both genes and one demonstrated promoter hypermethylation of the p16(INK4a) gene only. Eight of 91 RCCs showed aberrations of p14(ARF) or p16(INK4a) status and six of these featured gross extension into the renal vein. The results suggest that p14(ARF) and p16(INK4a) aberrations may play roles in the relatively late stage of renal tumorigenesis associated with tumor progression.

Hypomethylation of the MN/CA9 promoter and upregulated MN/CA9 expression in human renal cell carcinoma

MN/CA9 is a cancer-related gene, frequently activated in human renal cell carcinomas (RCCs). To reveal the activation mechanism, we investigated the relationship between methylation status of the MN/CA9 promoter region and gene expression using 13 human RCCs, and examined the effect of in vitro CpG methylation on the MN/CA9 promoter activity using a human RCC cell line (SK-RC-44), expressing MN/CA9. MN/CA9 expression was evaluated by RT-PCR and observed in 10 of 13 RCCs (77%). A total of 9 out of 10 MN/CA9 -positive RCCs (90%) contained clear cell components. Methylation status of 6 CpGs in the MN/CA9 promoter region was decided by using the bisulfite genomic sequencing protocol. Out of 13 RCCs 9 (69%) showed partial hypomethylation of the CpG at -74 bp, while the other 4 RCCs and 3 normal kidney tissue samples showed complete methylation. Hypomethylation of the CpG at -74 bp was strongly correlated with MN/CA9 expression. Luciferase assay revealed that the MN/CA9 promoter activity was strongly suppressed by methylation of the CpG at -74 bp. These findings suggest that hypomethylation of the CpG at -74 bp in the MN/CA9 promoter region might play an important role in this gene activation of human RCC.