Development of a prototype Open-close positron emission tomography system.

We developed a prototype positron emission tomography (PET) system based on a new concept called Open-close PET, which has two modes: open and close-modes. In the open-mode, the detector ring is separated into two halved rings and subject is imaged with the open space and projection image is formed. In the close-mode, the detector ring is closed to be a regular circular ring, and the subject can be imaged without an open space, and so reconstructed images can be made without artifacts.

Auditory resting-state functional connectivity in tinnitus and modulation with transcranial direct current stimulation.

Conclusions: The functional connectivity (FC) between the right and left auditory cortex is weak in tinnitus patients. Transcranial direct current stimulation (tDCS) over the auditory cortex has potential as a tool to modulate auditory-based FC.

Objective: This study investigated the effects of applying tDCS in tinnitus patients, and searched for modulation of brain networks in resting-state functional magnetic resonance imaging (rs-fMRI) through an analysis of FC with the stimulated brain region.

Myocardial energy provision is preserved by increased utilization of glucose and ketone bodies in CD36 knockout mice.

Aims: CD36 is an important transporter of long-chain fatty acids (LCFAs) in the myocardium. As we have reported previously, CD36-deficient patients demonstrate a marked reduction in myocardial uptake of (123)I-15-(p-iodophenyl)-(R, S)-methyl pentadecanoic acid (BMIPP), which is an analog of LCFAs, while myocardial (18)F-fluorodeoxy-glucose (FDG) uptake is increased. However, it has not been clarified whether energy provision is preserved in patients with CD36 deficiency.

Use of a Latent Topic Model for Characteristic Extraction from Health Checkup Questionnaire Data.

Objectives: When patients complete questionnaires during health checkups, many of their responses are subjective, making topic extraction difficult. Therefore, the purpose of this study was to develop a model capable of extracting appropriate topics from subjective data in questionnaires conducted during health checkups.

Methods: We employed a latent topic model to group the lifestyle habits of the study participants and represented their responses to items on health checkup questionnaires as a probability model.

Distributions of Pu isotopes in seawater and bottom sediments in the coast of the Japanese archipelago before and soon after the Fukushima Dai-ichi Nuclear Power Station accident.

A radioactivity measurement survey was carried out from 24 April 2008 to 3 June 2011 to determine the levels of plutonium isotopes and (240)Pu/(239)Pu atom ratios in the marine environments off the sites of commercial nuclear power stations around the Japanese islands; the sampling period extended to two months after the Fukushima Dai-ichi Nuclear Power Station accident. In our previous study (Oikawa et al., 2015), data on Pu isotopes and (241)Am in sediments have already been reported.

FBPA PET in boron neutron capture therapy for cancer: prediction of (10)B concentration in the tumor and normal tissue in a rat xenograft model.

Background: Boron neutron capture therapy (BNCT) is a molecular radiation treatment based on the (10)B (n, α) (7)Li nuclear reaction in cancer cells, in which delivery of (10)B by 4-borono-phenylalanine conjugated with fructose (BPA-fr) to the cancer cells is of critical importance. The PET tracer 4-borono-2-(18) F-fluoro-phenylalanine (FBPA) has been used to predict the accumulation of BPA-fr before BNCT. However, because of the difference in chemical structure between BPA-fr and FBPA and the difference in the dose administered between BPA-fr (therapeutic dose) and FBPA (tracer dose), the predictive value of FBPA PET for BPA-fr accumulation in the tumor and normal tissues is not yet clearly proven.

Feasibility studies towards future self-sufficient supply of the (99)Mo-(99m)Tc isotopes with Japanese accelerators.

In order to establish a self-sufficient supply of (99m)Tc, we studied feasibilities to produce its parent nucleus, (99)Mo, using Japanese accelerators. The daughter nucleus, (99m)Tc, is indispensable for medical diagnosis. (99)Mo has so far been imported from abroad, which is separated from fission products generated in nuclear reactors using enriched (235)U fuel.

Surgical treatment of patients with unruptured intracranial aneurysms.

We present our experience with elective microsurgical clipping of unruptured intracranial aneurysms (UIA) and analyze this management. A total of 150 patients with UIA were reviewed and data were collected with regard to age, sex, presence of symptoms, location and size of the aneurysms, surgical complications and postoperative 1 year outcomes. Aneurysm size was assessed either by three-dimensional CT angiography or digital subtraction angiogram.

Cell-sheet therapy with omentopexy promotes arteriogenesis and improves coronary circulation physiology in failing heart.

Cell-sheet transplantation induces angiogenesis for chronic myocardial infarction (MI), though insufficient capillary maturation and paucity of arteriogenesis may limit its therapeutic effects. Omentum has been used clinically to promote revascularization and healing of ischemic tissues. We hypothesized that cell-sheet transplantation covered with an omentum-flap would effectively establish mature blood vessels and improve coronary microcirculation physiology, enhancing the therapeutic effects of cell-sheet therapy.

Pacing and sensing interference by air bubble surrounding the non-extended helix of intact active fixation lead.

Background: Active fixation pacing leads with silicon cylinder tips have been used for their safety and flexibility. Measurement of baseline sensing/pacing characteristics before fixation of helix helps to identify the optimal pacing site, but we encountered difficulties in making these measurements despite multiple attempts with the model LPA 1200M lead. To identify the cause and overcome this complication, we compared 4 different retractable active fixation lead models, which enabled baseline sensing/pacing measurements before extension of helix.

Distribution of intravenously administered acetylcholinesterase inhibitor and acetylcholinesterase activity in the adrenal gland: 11C-donepezil PET study in the normal rat.

Purpose: Acetylcholinesterase (AChE) inhibitors have been used for patients with Alzheimer's disease. However, its pharmacokinetics in non-target organs other than the brain has not been clarified yet. The purpose of this study was to evaluate the relationship between the whole-body distribution of intravenously administered (11)C-Donepezil (DNP) and the AChE activity in the normal rat, with special focus on the adrenal glands.

Development of a PET/Cerenkov-light hybrid imaging system.

Purpose: Cerenkov-light imaging is a new molecular imaging technology that detects visible photons from high-speed electrons using a high sensitivity optical camera. However, the merit of Cerenkov-light imaging remains unclear. If a PET/Cerenkov-light hybrid imaging system were developed, the merit of Cerenkov-light imaging would be clarified by directly comparing these two imaging modalities.

Ultrahigh-resolution Cerenkov-light imaging system for positron radionuclides: potential applications and limitations.

Objective: Cerenkov-light imaging provides inherently high resolution because the light is emitted near the positron radionuclide. However, the magnitude for the high spatial resolution of Cerenkov-light imaging is unclear. Its potential molecular imaging applications also remain unclear.

Paradoxical reduction of cerebral blood flow after acetazolamide loading: a hemodynamic and metabolic study with (15)O PET.

Paradoxical reduction of cerebral blood flow (CBF) after administration of the vasodilator acetazolamide is the most severe stage of cerebrovascular reactivity failure and is often associated with an increased oxygen extraction fraction (OEF). In this study, we aimed to reveal the mechanism underlying this phenomenon by focusing on the ratio of CBF to cerebral blood volume (CBV) as a marker of regional cerebral perfusion pressure (CPP). In 37 patients with unilateral internal carotid or middle cerebral arterial (MCA) steno-occlusive disease and 8 normal controls, the baseline CBF (CBF(b)), CBV, OEF, cerebral oxygen metabolic rate (CMRO2), and CBF after acetazolamide loading in the anterior and posterior MCA territories were measured by (15)O positron emission tomography.

CBF/CBV maps in normal volunteers studied with (15)O PET: a possible index of cerebral perfusion pressure.

Local cerebral perfusion pressure (CPP) is a primary factor controlling cerebral circulation and previous studies have indicated that the ratio of cerebral blood flow (CBF) to cerebral blood volume (CBV) can be used as an index of the local CPP. In this study, we investigated whether the CBF/CBV ratio differs among different brain structures under physiological conditions, by means of (15)O positron emission tomography. Nine healthy volunteers (5 men and 4 women; mean age, 47.

Prediction model for glucose metabolism based on lipid metabolism.

Objectives: We developed a robust, long-term clinical prediction model to predict conditions leading to early diabetes using laboratory values other than blood glucose and insulin levels. Our model protects against missing data and noise that occur during long-term analysis.

Methods: RESULTS of a 75-g oral glucose tolerance test (OGTT) were divided into three groups: diabetes, impaired glucose tolerance (IGT), and normal (n = 114, 235, and 325, respectively).

Expression of platelet-derived growth factor receptor β is maintained by Prox1 in lymphatic endothelial cells and is required for tumor lymphangiogenesis.

The lymphatic system plays important roles not only in the physiological processes, such as maintenance of tissue fluid homeostasis, but also in pathological processes including the lymph node metastasis of tumor cells. Therefore, understanding of the molecular mechanisms underlying lymphatic vessel formation is crucial. Previous studies have shown that proliferation and migration of lymphatic endothelial cells (LECs) are activated by multiple types of signals mediated by tyrosine kinase receptors such as vascular endothelial growth factor receptor (VEGFR) 3.

Atrial pacing site and atrioventricular conduction in patients paced for sinus node disease.

Background: Unnecessary ventricular pacing in sinus node disease (SND) must be avoided. To test the hypothesis that in SND, with or without 1st degree atrioventricular (AV) block, cumulative percent ventricular pacing (cum%VP) can be limited by low right atrial septal (LRAS) instead of right atrial appendage (RAA) pacing.

Methods: We studied 102 dual-chamber pacemaker recipients with SND.

Roles of TGF-β family signals in the fate determination of pluripotent stem cells.

Members of the transforming growth factor-β (TGF-β) family have been implicated in embryogenesis as well as in the determination of the cell fates of mouse and human embryonic stem (ES) cells, which are characterized by their self-renewal and pluripotency. The cellular responses to TGF-β family signals are divergent depending on the cellular context and local environment. TGF-β family signals play critical roles both in the maintenance of the pluripotent state of ES cells by inducing the expression of Nanog, Oct4, and Sox2, and in their differentiation into various cell types by regulating the expression of master regulatory genes.

A hierarchical Bayesian framework to infer the progression level to diabetes based on deficient clinical data.

The increase in lifestyle-related diseases such as heart disease, diabetes, and high blood pressure is a challenging problem that should be resolved. The physiological mechanisms of the human body have long been studied using mathematical models. In particular, to study glucose metabolism, several models that infer insulin sensitivity and β-cell function have been developed.

Sodium channelopathy underlying familial sick sinus syndrome with early onset and predominantly male characteristics.

Background: Sick sinus syndrome (SSS) is a common arrhythmia often associated with aging or organic heart diseases but may also occur in a familial form with a variable mode of inheritance. Despite the identification of causative genes, including cardiac Na channel (SCN5A), the pathogenesis and molecular epidemiology of familial SSS remain undetermined primarily because of its rarity.

Methods And Results: We genetically screened 48 members of 15 SSS families for mutations in several candidate genes and determined the functional properties of mutant Na channels using whole-cell patch clamping.

[Long-term effects of tinnitus retraining therapy involving monaural noise generators].

We have previously reported on the effects of tinnitus retraining therapy (TRT) involving monaural noise generators (NGs) up to 24 months after the start of treatment (Eur Arch Otorhinolaryngol. 2013 Feb; 270(2) : 443-8.) but very few reports exist about the long-term effects of TRT for periods of over 2 years.

Myosin light chain kinase expression induced via tumor necrosis factor receptor 2 signaling in the epithelial cells regulates the development of colitis-associated carcinogenesis.

It has been suggested that prolonged inflammatory bowel diseases (IBD) may lead to colitis-associated carcinogenesis (CAC). We previously observed that the NF-κB activation in colonic epithelial cells is associated with increased tumor necrosis factor receptor 2 (TNFR2) expression in CAC development. However, the mechanism by which epithelial NF-κB activation leading to CAC is still unclear.

Transvenous embolization for carotid-cavernous fistula in a patient with vascular type of Ehlers-Danlos syndrome--direct superior ophthalmic vein approach: case report.

The vascular type of Ehlers-Danlos syndrome (vEDS) is an autosomal dominant hereditary disease characterized by connective tissue fragility throughout the body, including the arteries, viscera, and gastrointestinal tract. We report a case in which we performed transvenous embolization (TVE) via direct superior ophthalmic vein (SOV) approach to treat a direct carotid-cavernous fistula (CCF) in a patient with Ehlers-Danlos syndrome (EDS). The patient was a 37-year-old woman who developed tinnitus in her left ear and a headache during examination in the outpatient clinic of another hospital in order to make a definitive diagnosis of vEDS, and she was referred to our hospital and examined.