Search PubMed⌕ Search

Biomedical subjects

J Tanaka

Publications and source records attributed to J Tanaka.

At least 109 records · Page 6Linked to original sources
PubMed2001

Effect of melatonin on sleep and rectal temperature of young healthy evening types.

The present study assessed in healthy nocturnal juveniles the presence or absence of the hypnotic action of exogenous melatonin and its effect on core temperature by oral administration of exogenous melatonin at a pharmacologically low dose 15 min before going to bed at the normal time. Both sleep latency and the number of instances of waking up after falling asleep tended to decrease, while the amount of Stage 2 sleep increased significantly. However, no hypothermic action regarding the rectal temperature for changes in the circadian phase were observed. According to those results, it is possible that exogenous melatonin has some direct hypnotic action on habitual night sleep, although the extent of this action is considered to be relatively weak.

Administration, Oral↗
PubMed2001

Establishment and characterization of immortalized Schwann cells from murine model of Niemann-Pick disease type C (spm/spm).

Niemann-Pick disease type C (NPC) is characterized by an accumulation of unesterified cholesterol in the endosomal/lysosomal (E/L) system, resulting in progressive neurodegeneration and death during early childhood. To investigate the cellular pathomechanism of nervous system involvement in NPC, continuous neural cell lines are desirable. In this study, we obtained neuronal and Schwann cell cultures and established spontaneously immortalized Schwann cell lines from dorsal root ganglia and peripheral nerves of NPC model mouse (spm/spm). One of the cell lines, designated SPMS9, had distinct Schwann cell phenotypes and was maintained over 10 months without phenotypic alterations. The level of Npc1 mRNA was markedly decreased, and NPC1 protein was not detectable in SPMS9 cells. These cells contained intracytoplasmic granules positive for filipin cholesterol staining and immunoreactive for GM2 ganglioside. Electron-microscopically, intracytoplasmic polymorphous membranous inclusions and vacuoles were demonstrated in SPMS9 cells. The treatment with an inhibitor of ceramide-specific glucosyltransferase, N-butyldeoxynojirimysin (NB-DNJ) markedly reduced the intracytoplasmic granular immunofluorescence for GM2 ganglioside in SPMS9 cells, whereas the amount of filipin-positive granules remained unchanged. The SPMS9 cells retained vesicular fluorescence of cationic dye acriflavine 16-24 hours after loading, indicating the defect of transmembrane efflux pump activity of NPC1 in the E/L compartment in these cells. These immortalized Schwann cells can be useful in studies on the nervous system lesions in NPC.

Animals↗
PubMed2001

Recruitment of nonexpanded polyglutamine proteins to intranuclear aggregates in neuronal intranuclear hyaline inclusion disease.

Recruitment of polyglutamine-containing proteins into nuclear inclusions (NIs) was investigated in neuronal intranuclear hyaline inclusion disease (NIHID). Some polyglutamine-containing proteins, ataxin-2, ataxin-3, and TATA box binding protein (TBP), as well as unidentified proteins with expanded polyglutamine tracts were recruited into NIs with different frequencies. Ataxin-3 was incorporated into most of the NIs and disappeared from its normal cytoplasmic localization, whereas only a small fraction of NIs contained ataxin-2 and TBP. The consistent presence of ataxin-3 in NIs could reflect a biological feature of wild-type ataxin-3, which is translocated into the nucleus under pathological conditions and participates in the formation of aggregates. Ataxin-2 also accumulated in the nucleus, but was not necessarily incorporated into NIs, suggesting that transport of these cytoplasmic proteins into the nucleus and their recruitment into NIs are not wholly explained by an interaction with a polyglutamine stretch and must be regulated in part by other mechanisms. The prevalence of ubiquitin-immunopositive NIs was inversely correlated to neuronal loss in all cases examined. This correlation could be explained if NI formation is a protective mechanism involving the ubiquitin-proteasome pathway. This hypothesis is supported by the finding that the polyglutamine epitope in the center of NIs was surrounded by ubiquitin.

Adult↗
PubMed2001

Protective effect of a prosaposin-derived, 18-mer peptide on slowly progressive neuronal degeneration after brief ischemia.

SUMMARY: Slowly progressive degeneration of the hippocampal CA1 neurons was induced by 3-minute transient global ischemia in gerbils. Sustained degeneration of hippocampal CA1 neurons was evident 1 month after ischemia. To investigate the effects of an 18-mer peptide comprising the hydrophilic sequence of the rat saposin C domain (18MP) on this sustained neuronal degeneration, an intracerebroventricular 18MP infusion was initiated 3 days after ischemia. Histopathologic and behavior evaluations were conducted 1 week and 1 month after induction of ischemia. When compared with the vehicle infusion, 18MP treatment significantly increased the response latency time in a passive avoidance task. Increased neuronal density was also evident, as was the number of intact synapses in the hippocampal CA1 region at 1 week and 1 month after ischemia. 18MP treatment also significantly decreased the number of TUNEL-positive CA1 neurons 1 week after ischemia. Subsequent in vitro experiments using cultured neurons demonstrated that the 18MP at optimal extracellular concentrations of 1 to 100 fg/mL prevented nitric oxide-induced neuronal damage as expected and significantly up-regulated the expressions of bcl-x(L) mRNA and its translated protein. These results suggest that the gerbil model of 3-minute ischemia is useful in studying the pathogenesis of slowly progressive neuronal degeneration after stroke and in evaluating effects of novel therapeutic agents. It is likely that the 18MP at low extracellular concentrations prevents neuronal apoptosis possibly through up-regulation of the mitochondrial antiapoptotic factor Bcl-x(L).

Amino Acid Sequence↗
PubMed2001

Increased proportion of HLA-class-I-specific natural killer cell receptors (CD94) on peripheral blood mononuclear cells after allogeneic bone marrow transplantation.

In the present study, we investigated the inhibitory natural killer cell receptor (NKR) expression of CD94/NKG2A on PBMC after allogeneic bone marrow transplantation (BMT). The proportion of CD94 expression on PBMC was higher in patients without chronic graft-versus-host disease (cGVHD) and also in cGVHD patients with good response to conventional immunosuppressive therapy than in cGVHD patients with poor response. Also, the proportions of CD94+/CD3+ cells and CD94+/CD8+ cells were higher in cGVHD patients showing good response. In addition, the proportion of NKG2A-expressing cells was higher in patients without cGVHD than in patients with cGVHD. Therefore, chronic allostimulation after allo-BMT may augment the proportion of CD94/NKG2A-positive cells, and these cells may play some role in the regulation of alloresponse in some patients.

Antigens, CD↗
PubMed2001

Mechanism of superoxide generation system in indomethacin-induced gastric mucosal injury in rats.

We studied the mechanism of the superoxide generation system in indomethacin-induced gastric mucosal injury. First, 10 mM indomethacin had no direct effect on xanthine oxidase (XOD) activity. Next, we found that NADPH oxidase activity in polymorphonuclear leukocytes (PMN) of peripheral blood was significantly increased 6 h after administration of indomethacin. This phenomenon was inhibited by the injection of the NADPH oxidase inhibitor, diphenylene iodonium chloride (DIC). Activation of NADPH oxidase caused the component, p47phox to be translocated to the plasma membrane. Since indomethacin did not directly activate NADPH oxidase, we sought another route of activation of PMN. As IL-1 and TNF alpha play in the inflammation, we examined these cytokines in this study. TNF alpha was not detected but IL-1 was increased significantly 30 min after administration of indomethacin.

Animals↗
PubMed2001

Synthesis of (S)-ibuprofen via enantioselective degradation of racemic ibuprofen with an isolated yeast, Trichosporon cutaneum KPY 30802, in an interface bioreactor.

An interface bioreactor was used for the enantioselective degradation of (RS)-ibuprofen (IBU). An isolated yeast, Trichosporon cutaneum KPY 30802, preferentially degraded (R)-IBU to accumulate (S)-isomer. The addition of hydroquinone (10 mM) into a hydrophilic carrier was effective for the elevation of enantiomeric excess and the repression of excess degradation of (S)-IBU (E value, 9.3).

Journal Article↗
PubMed2001

Roles and mechanisms of action of pituitary adenylate cyclase-activating polypeptide (PACAP) in growth hormone and prolactin secretion.

It appears that PACAP has a direct action on somatotrophs to release GH. The intracellular signal transduction mechanisms for PACAP might be similar to but partly distinct from those for GRH. PACAP might play a role in GH secretion induced by serotoninergic mechanisms but not in ultradian rhythm of GH secretion in the rat. PACAP can stimulate PRL release from the pituitary in rats possibly through indirect paracrine effect. In addition, PACAP might participate in regulation of PRL secretion via hypothalamic VIP.

Adenoma↗
PubMed2001

Interstitial pneumonia accompanying ulcerative colitis.

We report a patient with ulcerative colitis complicated with idiopatic interstitial pneumonia, in whom the etiology of interstitial pneumonia was unknown, but immunological disturbance might have been involved. There are many complications with ulcerative colitis, but interstitial pneumonia is quite rare and its prognosis is quite poor. Antibiotic and steroid treatment were given under respiration supported therapy, but no response could be obtained. In the treatment of patients with ulcerative colitis, we must be mindful of interstitial pneumonia because the prognosis is quite poor.

Biopsy↗
PubMed2001

[Allogeneic hematopoietic stem cell transplantation for older adults (mini-transplantation)].

Allogeneic hematopoietic stem cell transplantation after conditioning regimen with high dose cytostatic drugs and total body irradiation may induce severe transplantation related complications especially in older adults. Recently, several reports showed successful engraftment in older patients with hematological and non hematological malignancies after reduced doses of cytostatic drugs. So called mini-transplantation (nonmyeloablative hematopoietic stem cell transplantation) might be able to induce graft-versus-leukemia/tumor effect (GVL/T) without severe transplantation related complications. Older patients and patients with reduced performance status induced by prior infectious and organ complications might benefit from this mini-transplantation strategy.

Aged↗
PubMed2001

Polymer properties on resins composed of UDMA and methacrylates with the carboxyl group.

The properties of dental matrix resins have been improved by synthesis of new monomers. However, except for improvements in water-resistance, monomers with better mechanical properties than Bis-GMA and UDMA could not being synthesized. Changing the point of emphasis, we tried to improve the mechanical properties controlling the matrix resin higher structure using noncovalent bonds. We prepared a matrix resin structured by UDMA, which is a high viscosity base monomer with imino groups, and by a low viscosity acidic monomer with carboxyl groups, which permits noncovalent bonds such as hydrogen bonds or electrostatic interaction with imino groups. The maximal mechanical strength for matrix resins structured by UDMA and an acidic monomer was obtained with a composition of imino groups and carboxyl groups at a ratio of 1:1. This mechanical strength value was higher than those obtained with UDMA resin or with a Bis-GMA/TEGDMA/UDMA resin with typical composition. The improvement in mechanical properties may be due to the complex based on noncovalent bonds, between the imino groups of UDMA and the carboxyl groups of the acidic monomers.

Aminobenzoates↗
PubMed2001

Acid-base status and blood gas arterial values in free-ranging sika deer hinds immobilized with medetomidine and ketamine.

Ten free-ranging female sika deer (Cervus nippon) were captured to obtain the reference values for acid-base status and blood gas when immobilized with the combination of medetomidine and ketamine. The mean +/- SE of PaCO2, PaO2, and HCO3- were 58.1 +/- 6.1 mmHg, 58.8 +/- 6.4 mmHg, and 36.0 +/- 4.4 mmol/l, respectively. Although acidosis and alkalosis occurred in three and two animals, respectively, no serious conditions were observed. The blood values, however, suggest that some degree of hypoxemia and respiratory acidosis with metabolic alkalosis are developed. The trapped deer showed a significantly higher than normal rectal temperature reflective of exertion.

Acid-Base Equilibrium↗
PubMed2001

[A case of combined operation of aortic valve slicing and root remodeling for ascending aortic aneurysm with aortic regurgitation].

A 56-year-old female admitted with severe back pain, and her chest computed tomography demonstrated non-dissecting sclerotic aneurysm of the ascending aorta. Aortography and echocardiography showed marked dilatation of the ascending aorta and the Valsalva sinuses resulting in disappearance of the sinotubular junction. Aortic regurgitation of grade three was, also, recognized. A combined operation of aortic valve slicing of the right and the left coronary cusps and aortic root remodeling (Yacoub's method) was successfully performed. A woven Dacron double-veloured graft (Hemashield) of 22 mm in diameter was used for reconstruction of the ascending aorta and its root. Postoperative aortography figured the new sinotubular junction and the new Valsalva-like sinus composed by the graft, and aortic regurgitation was controlled to grade one.

Aorta↗