Transition between internal transport barriers with different temperature-profile curvatures in JT-60U Tokamak plasmas

A spontaneous transition phenomena between two states of a plasma with an internal transport barrier (ITB) is observed in the steady-state phase of the magnetic shear in the negative magnetic shear plasma in the JT-60U tokamak. These two ITB states are characterized by different profiles of the second radial derivative of the ion temperature inside the ITB region (one has a weak concave shape and the other has a strong convex shape) and by different degrees of sharpness of the interfaces between the L mode and the ITB region, which is determined by the turbulence penetration into the ITB region.

Exfoliation of gastric pit-parietal cells into the gastric lumen associated with a stimulation of isolated rat gastric mucosa in vitro: a morphological study by the application of cryotechniques

It is clinicopathologically important to elucidate the cell kinetics for the maintenance of normal gastric epithelium. In a rat gastric mucosa isolated after stimulation, a number of cells were exfoliated into the gastric lumen of the pit region. The present study was undertaken to clarify the origin of exfoliated cells and their histochemical profiles by taking the advantages of cryotechniques. As results, most of the exfoliated cells were identified as pit-parietal cells labeled with both peanut-lectin and anti-H+/K+-ATPase antibody. Quantitative analysis verified a time-dependent increase in the number of exfoliated cells in the gastric mucosa isolated after stimulation. The exfoliated cells exhibited a diffuse intracellular staining for E-cadherin, suggesting a dissociation of the adhesion molecule prior to the cell exfoliation. It should be noted that most of the exfoliated cells were negative to the apoptotic markers (TUNEL staining and caspase-3). Ultrastructurally, autophagosome-like structures consisting of H+/K+-ATPase positive membranes were frequently seen in the exfoliated pit-parietal cells. In addition, the pit-parietal cell exfoliation was accompanied by sealing of their basal portion with the cytoplasmic processes of adjacent surface mucous cells. The present morphological findings provide a new insight into the cell kinetics in the gastric epithelium in vitro.

Depression among caregivers of the frail elderly in Japan before and after the introduction of the Public Long-Term Care Insurance System

Cross sectional studies were conducted in five towns in Japan before and after the introduction of the Long-term Care Insurance System (LTCIS), in order to evaluate the factors relating to depression among family caregivers for the frail elderly. Depressive caregivers were more likely to consult with their doctors, to be in poor health, to care for demented elderly with behavioral disturbances than the non-depressive caregivers both before and after the LTCIS. Before LTCIS, depressive caregivers were more likely to attend to the elderly for more than 16 hours per day than their counterparts. After the LTCIS, depressive caregivers were more likely to be a spouse, to care for a frail elderly male, and less likely to be able to go out without accompanying the elderly than their counterparts. Even after the introduction of LTCIS, half of the caregivers were depressive. It is suggested that a government agency should be created to support not only the frail elderly but also their caregivers.

Mucosubstance histochemistry and pathogenesis of acquired cholesteatoma

Mucosubstance histochemical study of 33 cholesteatoma tissues was performed to clarify the distribution and character of mucin in the perimatrix. Mean density of glandular cysts was 0.18 per mm(2). Mean frequency of ruptured cysts was 0.16 per cyst. Glandular cysts as well as hollow spaces in the perimatrix were filled with sulfomucin and sialomucin. Fragments of mucin were found in some macrophages and multinucleated giant cells. Since phagocytosis is host defenses attempt, the process indicates that mucin in the perimatrix is a cause of inflammation. Sialomucin infiltrated in the subepidermis where the epidermis formed papillary proliferation without an apparent sign of inflammation. Six glandular cysts were found in the matrix and the debris. They may have been eliminated from the perimatrix as a sequel to cholesteatoma growth. These findings suggest that embedded mucosa in the perimatrix may play a crucial role in pathogenesis of acquired cholesteatoma.

Linkage disequilibrium and association with methamphetamine dependence/psychosis of mu-opioid receptor gene polymorphisms

Several studies indicate that the mu-opioid receptor plays a role in addiction not only to opiate drugs but also to alcohol and non-opiate addictive drugs. Our studies aim to reveal the associations between gene polymorphisms and methamphetamine (MAP) dependence/psychosis. We newly identified several polymorphisms and four substantial linkage disequilibrium (LD) blocks in the mu-opioid receptor (OPRM1) gene. We found significant differences in both genotype and allele frequencies of the single-nucleotide polymorphism (SNP) IVS2+G691C between control (n=232) and MAP-dependent/psychotic patients (n=128). There was also a significant association between IVS2+G691C and patients with transient psychosis. These results suggest that the OPRM1 gene variations may be a factor in development and prognosis of MAP psychosis.

Ultrastructural transformation of gastric parietal cells reverting from the active to the resting state of acid secretion revealed in isolated rat gastric mucosa model processed by high-pressure freezing

To elucidate a functional transformation of gastric parietal cells, we have newly developed an isolated rat gastric mucosa model whose parietal cells exhibited a reverting process from the active to the resting state of acid secretion. Briefly, the parietal cells were treated with cimetidine following prior stimulation of acid secretion in the model, and cryofixed by plunge freezing for light microscopy or high-pressure freezing for electron microscopy. As a result, immunohistochemistry of H(+)/K(+)-ATPase demonstrated a progressive translocation of H(+)/K(+)-ATPase from the apical to the cytoplasmic region. The ultrastructure of parietal cells at 5 min in the reverting phase was quite similar to that of maximally stimulated one. However, the apical microvilli of intracellular canaliculi (IC) changed bulbous by degrees, resulted in complete occlusion of IC at 60 min in the reverting phase. The apical membranes were subsequently internalized into the cytoplasm forming unique penta-laminar membranes. Interestingly, at 90 min in the reverting phase, the penta-laminar membranes formed a number of multilamellar autophagosomes that were intensely labeled for H(+)/K(+)-ATPase. Then, the parietal cells exhibited well-developed Golgi apparatus and lysosomal compartments involving the multilamellar membranes at 105 min, and mostly reverted to their resting conformation at 120 min in the reverting phase. Corresponding to the ultrastructural changes of microvilli, the immunohistochemistry of ezrin showed a dissociation of ezrin from the apical region at 30 min in the reverting phase. The present findings provide new insights into the functional transformation in gastric parietal cells reverting to their resting conformation.

Three-dimensional regular arrangement of the annular ligament of the rat stapediovestibular joint

The stapes footplate articulates with the vestibular window through the annular ligament. This articulation is known as the stapediovestibular joint (SVJ). We investigated the ultrastructure of adult rat SVJ and report here on the characteristic ultrastructure of the corresponding annular ligament. Transmission electron microscopy showed that this annular ligament comprises thick ligament fibers consisting of a peripheral mantle of microfibrils and an electron-lucent central amorphous substance that is regularly arranged in a linear fashion, forming laminated structures parallel to the horizontal plane of the SVJ. Scanning electron microscopy revealed that transverse microfibrils cross the thick ligament fibers, showing a lattice-like structure. The annular ligament was vividly stained with elastica van Gieson's stain and the Verhoeff's iron hematoxylin method. Staining of the electron-lucent central amorphous substance of the thick ligament fibers by the tannate-metal salt method revealed an intense electron density. These results indicate that the annular ligament of the SVJ is mainly composed of mature elastic fibers.

The cryofixation of isolated rat gastric mucosa provides new insights into the functional transformation of gastric parietal cells: an in vitro experimental model study

Cryofixation is currently accepted as the best initial fixation step to preserve not only the fine structure but also the antigenicity of biological samples. To elucidate the functional transformation of gastric parietal cells, we have newly developed an in vitro experimental model, named the isolated gastric mucosa. In this study, acid secretion of the parietal cell was stimulated with histamine or inhibited with cimetidine, and the samples were cryofixed by plunge freezing for light microscopy or high-pressure freezing for electron microscopy. As a result, the organization of glandular cells was well-preserved and quite similar to freshly excised rat gastric mucosa for at least 2 h after isolation. Immunohistochemistry of H+/K+-ATPase demonstrated a translocation of H+/K+-ATPase from the cytoplasm to the apical membrane associated with histamine-stimulation. In cimetidine-treated mucosa, most of the parietal cells were morphologically in the resting state, showing numerous tubulovesicles in their cytoplasm. In contrast, histamine-stimulated parietal cells exhibited well-developed intracellular canaliculi lined with long microvilli. To the best of our knowledge, the present study is first to demonstrate an electron micrograph that strongly suggests a membrane fusion between the tubulovescile and the apical membrane. Moreover, a stimulation-associated translocation of ezrin was clearly shown from the cytoplasm to the apical region, corresponding to apical microvilli development in the isolated gastric mucosa model. We here describe the preparation of the isolated rat gastric mucosa model, which provides new insights into the functional transformation of parietal cells by the application of cryotechniques.

Confirmation of mucin in lymphatic vessels of acquired cholesteatoma

Abundant inflammatory cells infiltrate in the advancing front of the cholesteatoma perimatrix towards the middle ear mucosa. However, the cause of inflammation is not yet clear. The middle ear mucosa is often embedded in the cholesteatoma perimatrix. We hypothesized that the embedded mucosa is the cause of inflammation. Surgical specimens obtained from 20 cases of acquired cholesteatoma were used for the study. Lymphatic vessels were stained by the immunohistochemical method using the antibody against podoplanin. Mucin was simultaneously stained by alcian blue. The results of our examination were the following: (1) the presence of infiltrating mucin in the perimatrix; (2) the degeneration and reduction of lymphatic vessels; (3) the accumulation of inflammatory cells around morbid lymphatic vessels. Based on our findings, cholesteatoma can be defined as an inflammation affected by infiltrating mucin that escaped from embedded mucosa in the perimatrix.

Current clamp at zero level in JT-60U current hole plasmas

It is found that no current is driven in a central region of a tokamak plasma once the central current density becomes nearly zero ("current hole"), in spite of high electric conductivity, at the current drive by a toroidal electric field and a radio-frequency wave in experiments on the JT-60U tokamak. This is a new, stiff, self-organized structure of a magnetic field in an axisymmetric toroidal plasma.

Application of 10-μm thin stainless foil to a new assembly of the specimen carrier in high-pressure freezing

High-pressure freezing (HPF) has been accepted generally as the most reliable method for cryoimmobilization of biological samples. However, the depth of vitreous freezing in biological samples was less than expected, probably because of the poor thermal conductivity with high water contents. In this study, we introduce a new assembly of the specimen carrier using a 10-microm thin stainless foil for the specimen chamber cover in the HPF technique and describe the fine structure of rat gastric glands processed with the assembly. A low-magnification view of the gastric surface region showed a well-preserved morphology in which the vitreous freezing reached deeper than 100-microm from the freezing face. The present results prove that the 10-microm thin stainless foil is useful in HPF, providing deep vitrification in biological samples.

Measurement of turbulence decorrelation during transport barrier evolution in a high-temperature fusion plasma

A low power polychromatic beam of microwaves is used to diagnose the behavior of turbulent fluctuations in the core of the JT-60U tokamak during the evolution of the internal transport barrier. A continuous reduction in the size of turbulent structures is observed concomitant with the reduction of the density scale length during the evolution of the internal transport barrier. The density correlation length decreases to the order of the ion gyroradius, in contrast with the much longer scale lengths observed earlier in the discharge, while the density fluctuation level remain similar to the level before transport barrier formation.

Changes in Expression of the Mouse Homologues of KIAA Genes after Subchronic Methamphetamine Treatment

Amphetamine abuse may be associated with adaptive changes in gene expression in the brain. In the present study, a newly developed cDNA array system comprising mouse KIAA (mKIAA) cDNA clones was used to examine the gene expression affected by chronic methamphetamine treatment. Approximately 800 mKIAA clones were blotted onto a nylon membrane and hybridized with 33P-labeled cDNA derived from mRNAs isolated from the whole brains of mice that had been treated daily with saline or methamphetamine (2 mg/kg, i.p.) for 2 weeks. The arrays displayed robust hybridization for almost all transcripts. The results obtained from five experiments were averaged, each performed with triplicate samples. Several clones were chosen as positive candidates for methamphetamine-induced changes; however, only Per2 and mKIAA0099 genes showed a significantly increased expression (P < .05). Subsequently, with the focus on the period-related proteins, the expression of these proteins in various parts of the rat brain were assessed by immunoblot analysis. Chronic administration of methamphetamine (8 mg/kg, i.p., for 10 days) caused increased Per2 protein expression in the hippocampus. Interestingly, chronic methamphetamine treatment at a lower dose (4 mg/kg, i.p., for 10 days) induced an increase in SCN circadian oscillatory protein (SCOP) expression, also in the hippocampus. These data suggest that long-lasting alterations of the period-related gene expressions in the hippocampus might play an important role in methamphetamine addiction.

Formation of advanced tokamak plasmas without the use of an ohmic-heating solenoid

A new operational scenario of advanced tokamak formation was demonstrated in the JT-60U tokamak. This was accomplished by electron cyclotron and lower hybrid waves, neutral beam injection, and the loop voltage supplied by the vertical field and shaping coils. The Ohmic heating (OH) solenoid was not used but a small inboard coil (part of the shaping coil), providing less than 20% of total poloidal flux, was used. The plasma thus obtained had both internal and edge transport barriers, with an energy confinement time of 1.6 times H-mode scaling, a poloidal beta of 3.6, and a normalized beta of 1.6, and a large bootstrap current fraction (>90%). This result opens up a possibility to reduce, and eventually eliminate, the OH solenoid from a tokamak reactor, which will greatly improve its economic competitiveness.