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Biomedical subjects

T Miyazawa

Publications and source records attributed to T Miyazawa.

At least 199 records · Page 11Linked to original sources
PubMed1997

Absorption and distribution of tea catechin, (-)-epigallocatechin-3-gallate, in the rat.

To investigate the absorption and metabolism of an anticarcinogenic tea catechin, (-)-epigallocatechin-3-gallate (EGCg), in rats, a newly developed chemiluminescence-detection high-performance liquid chromatography (CL-HPLC) method was employed and the EGCg concentrations in blood plasma, liver, brain, small intestinal mucosa and colon mucosa were determined before and after EGCg administration. The recovery of EGCg, extracted consecutively with ethyl acetate and methanol, was 86.1% from plasma and 64.5-74.2% from the tissue samples. The EGCg concentrations of plasma and tissue samples from the control rat (before EGCg administration) were all below the detection limit (< 0.002 nmol/mL, 0.002 nmol/g), but 60 min after a single oral administration of EGCg (500 mg/kg body weight), the levels increased, reaching 12.3 nmol/mL in plasma, 48.4 nmol/g in liver, 0.5 nmol/g in brain, 565 nmol/g in small intestinal mucosa and 68.6 nmol/g in colon mucosa. The EGCg levels found in the tissues corresponded to 0.0003-0.45% of ingested EGCg. The results indicate that tea catechin, EGCg, is absorbed from the digestive tract, with the intestinal mucosa the most enriched of the organelles. This may explain the potent antioxidant function of EGCg in inhibiting colon mucosal phospholipid hydroperoxidation in the prevention of rat colonic carcinogenesis.

Animals↗
PubMed1997

[Cell surface antigens on inflammatory cells in the paranasal mucosa of patients after macrolide therapy].

Low-dose and long-term administration of 14-lactone-ring macrolides (macrolide therapy) has been reported to be very effective in the treatment of chronic sinusitis, including the sinobronchial syndrome. However, the mechanism whereby the chronic inflammation is down-regulated is unknown. The present study was carried out to immunohistochemically identify the antigens expressed on the surfaces of inflammatory cells in the paranasal mucosa and nasal polyps of patients who responded well to macrolide therapy and in control patients. HLA-DR (a class-II antigen) was detected on relatively large, irregularly shaped cells and on small, round cells in the submucosa. The former cells were considered to be macrophages because they were CD68-positive. Thus, in the paranasal mucosa macrophages act antigen-presenting cells. The numbers of HLA-DR-positive cell and CD68-positive cells varied among the patients and did not differ significantly between the patients who had under gone macrolide therapy and those who had not. There were significantly fewer CD4-positive T lymphocytes in the submucosa of patients who had under gone macrolide therapy than in the control patients, but the number of CD8-positive T lymphocytes did not differ significantly between the two groups of patients. The mean ratio of the number of CD4-positive to the number of CD8-positive T lymphocytes (CD4/CD8) in the submucosa of the patients who had under gone macrolide therapy, 0.77, was significantly lower than in the control patients, 1.92 (< 0.01). HLA-DR expression induces differentiation of and cytokine production by CD4-positive T lymphocytes in the presence of co-stimulators. The present results suggest that macrolides may affect the manner of interaction between antigen-presenting cells such as macrophages and CD4-positive T lymphocytes.

Anti-Bacterial Agents↗
PubMed1997

[A case of jugular foramen neurinoma originating from glossopharyngeal nerve].

A 39-year-old man was admitted with right hearing loss, tinnitus and vertigo. Neurological examination on admission revealed right facial palsy, right acoustic nerve disturbance and cerebellar ataxia. CT scan demonstrated a mass with intra-and extracranial extension in the pyramid bone concomitant with enlarged jugular foramen. MRI showed a ring-like enhanced, extra-axial mass in the right CP angle. Cerebral angiography showed no tumor stain. Venous phase of VAG revealed lateral displacement of the right sigmoidal sinus and obstruction of the internal jugular vein. Three dimensional CT was very useful to reveal enlarged jugular foramen. The tumor was resected totally and was approached through a right suboccipital craniectomy and mastoidectomy on July, 1994. Surgery confirmed that the tumor was a neurinoma originating from the glossopharyngeal nerve. After the operation, right facial palsy developed and transient fugitive CSF leakage was observed, but the patient is doing well. There was no amelioration of right hearing loss. JFN originating from the glossopharyngeal nerve is rare. Twenty-five cases of glossopharyngeal neurinoma are reviewed.

Adult↗
PubMed1997

Phylogenetic analysis of feline immunodeficiency virus isolated from cats in Taiwan.

Feline immunodeficiency virus was isolated from four cats in Taiwan. The isolates were designated TI-1, TI-2, TI-3 and TI-4. Each was isolated from PBMCs following co-cultivation of PBMCs with a feline T-lymphoblastoid cell line (MYA-1 cells). However, the Taiwanese isolates did not grow in a feline kidney cell line (CRFK cells). The nucleotide sequences of the V3-V5 region of the envelope gene of the Taiwanese isolates were determined and compared with those of previously described isolates. Phylogenetic analysis of this region indicates that Taiwanese isolates belong to subtype C.

Amino Acid Sequence↗
PubMed1997

[Dynamic MR hepatocholangiography with the SIP Fast GRE (saturation inversion projection fast gradient echo) method].

The purpose of this study was to assess the utility of dynamic MR hepatocholangiography with the Gd-EOB-DTPA enhanced SIP Fast GRE sequence in the hepatobiliary system. The SIP Fast GRE sequence was used for sequential imaging of the hepatobiliary system with a frame rate of 3 sec in a 256 x 192 matrix. Dynamic sequential acquisition was performed for 51 min before and after the injection of 30 mu mol/kg of Gd-EOB-DTPA in a rabbit. Dynamic images of the hepatobiliary system were obtained in the rabbit study. Dynamic MR hepatocholangiography provides better functional information than conventional MR cholangiography.

Animals↗
PubMed1996

Repeated hyperbaric oxygen induces ischemic tolerance in gerbil hippocampus.

Hyperbaric oxygen (HBO; 100% oxygen at 2 atmospheres absolute) was administered for 1 h to male Mongolian gerbils either for a single session or every other day for five sessions. Two days after HBO pretreatment, the gerbils were subjected to 5 min of forebrain ischemia by occlusion of both common carotid arteries under anesthesia. Seven days after recirculation, neuronal density per 1-mm length of the CA1 sector in the hippocampus was significantly better preserved in the five-session HBO pretreatment group (n = 10: 175.7 (47.8/mm, 54.9% of normal) than in the ischemic control group (n = 10: 26.2 (11.6/mm, 8.0% of normal) and in the single-session HBO pretreatment group (n = 7: 37.3 (21.7/mm, 11.4% of normal). Immunohistochemical staining for the 72-kDa heat-shock protein (HSP-72) in the CA1 sector performed 2 days following pretreatment revealed that the five-session HBO pretreatment increased the amount of HSP-72 present compared with that in the ischemic control group and in the single HBO pretreatment group. These results suggest that tolerance against ischemic neuronal damage was induced by repeated HBO pretreatment, which is thought to occur through the induction of HSP-72 synthesis.

Animals↗
PubMed1996

Inhibition of mucosal lipid hyperoxidation by green tea extract in 1,2-dimethylhydrazine-induced rat colonic carcinogenesis.

Phosphatidylcholine hydroperoxide (PCOOH) measured using a chemiluminescence detector to examine colonic mucosal lipid hyperoxidation increased after injection of 1,2-dimethylhydrazine and green tea extract (GTE), which we previously showed inhibited carcinogenesis and oxidative DNA damage in the gastrointestinal tract. Therefore, the hyperoxidation of membrane phospholipids reflected well the degree of DNA damage and carcinogenic alteration, and may be a useful intermediate biomarker for initiation of carcinogenesis.

1,2-Dimethylhydrazine↗
PubMed1996

Fluorescence polarization study on the dynamics and location of peroxidized fluorescent phospholipids in liposomes.

Motional properties of fluorescent substances produced by lipid peroxidation by a time-resolved fluorescence polarization technique were studied. When liposomes containing phosphatidylethanolamine (PE) and linoleic hydrocarbon chain were incubated at 37 degrees C, fluorophores absorbing maximally at 360 nm and emitting near 430 nm were produced. Their fluorescence anisotropy decay measured at 23 degrees C was fitted well with a sum of a fast relaxation and a time-independent residual term. With the increase of oxidation degree, the time constant of the relaxation term increased. This may be explained by alteration in the membrane structure or by modification of the fluorescent products themselves. Information on the location of the fluorescent products was obtained when their motional property was compared with those of various extrinsic probes that were incorporated at different positions of the lipid bilayer. It was found that the motional property of the fluorescent oxidation products is similar to that of 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene, a rod-shaped hydrophobic probe with a charged terminal. Other probes sensing the polar region or the hydrophobic region of the membrane were characterized by a lower order parameter. It is suggested that the fluorescent oxidation products have a polar moiety located at the membrane surface and attached to the amino group of PE while the tail part being buried in the hydrophobic region of the membrane. This picture is supported by fluorescence quenching experiments with the aqueous quencher Co2+. On the other hand, fluorophores produced by the reaction of malondialdehyde and PE suggested to have a chemical structure in which the angle between the absorption and emission dipole moments is very large. On the basis of these observations, the production pathway of fluorophores in oxidized membranes is discussed.

Fluorescence Polarization↗
PubMed1996

Age-related change of phosphatidylcholine hydroperoxide and phosphatidylethanolamine hydroperoxide levels in normal human red blood cells.

The age-related occurrence of phosphatidylcholine hydroperoxide (PCOOH) and phosphatidylethanolamine hydroperoxide (PEOOH) in normal human red blood cells (RBC) was confirmed by using chemiluminescence detection-high performances liquid chromatography (CL-HPLC). The concentration (mean +/- S.D.) for the healthy young adult (22-27 of age, n = 20) was 93 +/- 17 pmol PCOOH and 121 +/- 20 pmol PEOOH/ml packed RBC, while for the aged adult (56-92 of age, n = 20) the peroxide content was significantly higher, 162 +/- 52 pmol PCOOH and 186 +/- 40 pmol PEOOH/ml packed RBC. These results indicate that oxidative stress occurs constantly on RBC, even in normal humans, and that the susceptivity significantly increases with age.

Adult↗
PubMed1996

beta-carotene as a high-potency antioxidant to prevent the formation of phospholipid hydroperoxides in red blood cells of mice.

In order to investigate the antioxidant effect of beta-carotene in vivo, phospholipid hydroperoxides and beta-carotene isomers in red blood cells (RBC), plasma and tissue organelles were quantitatively measured after the oral administration of beta-carotene (94.8% all-trans-beta-carotene) to mice. Three groups of 24 mice each were fed for 1 week on a semisynthetic diet supplemented with either 0.6% or 3.0% beta-carotene/diet or maintained on a control (beta-carotene-unsupplemented) diet. The RBC phospholipid hydroperoxides showed a significant decrease followed by an increase of beta-carotene intakes; i.e., 201, 16 and 4 pmol of phosphatidylcholine hydroperoxide/ml packed RBC, and 108, 22 and 8 pmol of phosphatidylethanolamine hydroperoxide/ml packed RBC, in the mice given the control diet, 0.6% carotene diet and 3.0% carotene diet, respectively. The RBC beta-carotene increased from 14 to 43 pmol/ml packed RBC as followed by the increase of beta-carotene intakes. Such a potent antioxidant effect of beta-carotene as observed in RBC was not confirmed in the plasma, liver or lungs, although their beta-carotene contents increased. The beta-carotene ingestion increased the all-trans-beta-carotene and retinol contents in RBC, plasma, liver and lungs, but the alpha-tocopherol content decreased. In the beta-carotene-supplemented (6 g and 30 g/kg diet) mice, cis-beta-carotene content was relatively higher in the RBC (25-35% of total beta-carotene) than that in the plasma, liver and lungs. The present findings indicate that not only does beta-carotene act as a potent antioxidant in vivo but also its antioxidant effect is very specific in the RBC phospholipid bilayers rather than in the plasma and other tissue organelles.

Animals↗
PubMed1996

Stapes fixation associated with symphalangia.

We describe a 10-year-old boy and his 9-year-old sister, both of whom had bilateral hearing loss associated with ankylosis of the proximal interphalangeal joints (symphalangia). They had no other abnormal findings except hearing loss and ankylosis of the joints of some fingers and toes on systemic examination. The cause of conductive hearing loss in both cases was bony fusion between the stapes and the bone of the oval window niche. There were no other anatomical abnormalities in the middle or the external ear. The patients' hearing improved markedly after stapes surgery. Histopathologic examination of the stapes revealed an abnormal zone of ossification near the anterior annular ligament and calcification in the annular ligament, which seemed to be the cause of the stapes fixation.

Child↗
PubMed1996

HLA associations in otosclerosis in Japanese patients.

Otosclerosis is a disease of the otic capsule that is caused by abnormal resorption and redeposition of bony tissue. Sixty-two unrelated Japanese patients exhibiting clinical otosclerosis were typed for HLA-A, -B, -C antigens. Twenty-one of the patients were also typed for DR antigens. The frequency of HLA-Aw33 was significantly higher in otosclerosis patients than in the control group (24.2% vs 9.5%). This finding suggests that the presence of HLA-Aw33 antigens may be related to an increased susceptibility to otosclerosis or to its clinical outcome.

Adolescent↗
PubMed1996

Regulatory properties of the integrated long terminal repeat of the feline immunodeficiency virus.

To examine the regulatory properties of feline immunodeficiency virus (FIV) long terminal repeat (LTR) integrated into host chromatin, Crandell feline kidney cells were stably transfected with the FIV LTR that directs the bacterial chloramphenicol acetyltransferase (CAT) gene. Using these cells, we examined the effects of treatment with several chemical agents, infection with feline viruses, or transfection with effector plasmids expressing FIV gene products on FIV LTR-directed gene expression. Among them, treatment with the phorbol ester (a strong activator of protein kinase C), forskolin (an inducer of cyclic-AMP), 5-azacytidine (a DNA methylation antagonist), or infection with feline herpesvirus type 1 (FHV-1), resulted in induction of CAT activity in the cells. These results suggest that the integrated FIV LTR is stimulated by cellular transcriptional factors induced by phorbol ester, forskolin and FHV-1, and is also inactivated by DNA methylation. Furthermore, this permanent cell line can be used as a screening system of activators of the FIV LTR.

Animals↗
PubMed1996

Neurotoxicity of gadolinium contrast agents for magnetic resonance imaging in rats with osmotically disrupted blood-brain barrier.

The neurotoxicity of intravenously injected Gadolinium (Gd) complexes to rats with disrupted blood-brain barrier (BBB) was evaluated. After disruption of the BBB by infusion of mannitol solution, one of several contrast agents tested was injected intravenously at a dose of 1 or 3 mmol Gd/kg, and neurological symptoms were graded. The concentrations of Gd in brain and plasma were also measured. Injection of Gd-DTPA at a dose of 3 mmol Gd/kg did not change behavior. On the other hand, Gd-DTPA-BMA, Gd-DO3A-butrol, and Gd-DO3A-HP each induced behavioral impairments, and some animals died within 1 h after injection. Gd-DO3A-HP showed lethal effect even at a dose of 1 mmol/kg. The concentration of Gd in the brain of the animals injected with Gd-DO3A-HP at 3 mmol Gd/kg was essentially the same as that of animals injected with Gd-DTPA at the same dose. The neurotoxicity of the contrast agents tested was graded as follows: Gd-DTPA < or = Gd-DTPA-BMA = Gd-DO3A-butrol < Gd-DO3A-HP.

Animals↗
PubMed1996

Pontine glioma with osteoblastic skeletal metastases in a child.

BACKGROUND: The development of systemic metastases from primary intracranial gliomas is rare. We report here a rare case of pontine glioma with osteoblastic skeletal metastases. CASE: This 12-year-old boy presented with a 4-month history of hoarseness, dysphagia, and a progressively ataxic gait. Cranial computed tomography (CT) and magnetic resonance imaging (MRI) revealed a brain stem tumor that was diagnosed as a low grade glioma by stereotactic biopsy. Twelve months later following chemotherapy and radiotherapy, neurologic examination and neuroradiologic studies disclosed a recurrence of the pontine glioma. Skeletal roentgenograms revealed widespread osteoblastic metastases in the skull, vertebral bodies, pelvis, and long bones. A specimen from the iliac bone demonstrated cells that were immunoreactive glial fibrillary acidic protein (GFAP). DISCUSSION: The mechanism of how glioma cells determine their biologic behavior at bony metastatic sites is not known. Infratentorial gliomas, which occur frequently in young patients and demonstrate active bony metabolism, may stimulate osteoblastic cells, and induce osteoblastic changes.

Bone Neoplasms↗