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Biomedical subjects

M Itoh

Publications and source records attributed to M Itoh.

At least 253 records · Page 14Linked to original sources
PubMed2000

Lipid peroxidation levels in rat cardiac muscle are affected by age and thyroid status.

Free radicals, hydroxyperoxides and H(2)O(2) are all known to damage cell components. This study was designed to compare the concentrations of hydroxyperoxide and free radical scavengers in the cardiac muscles of old rats in the hyper- or hypothyroid condition, to determine whether rates of peroxidation would differ with age, thyroid status, or both. Rats were rendered hyper- or hypothyroid by administration of l-thyroxine or methimazole for 4 weeks. Among the old rats, the lipid peroxide (LPO) concentrations, measured as thiobarbituric acid (TBA) reactants, were significantly greater in the hyperthyroid than in the euthyroid state and the LPO concentrations measured as TBA+Fe(3+) reactants, which may be precursors of LPO, were significantly greater in the hyperthyroid state, whereas in young rats, the LPO concentrations measured by TBA or TBA+Fe(3+) methods did not differ significantly in the hyperthyroid state. In the euthyroid state, the concentration of LPO measured as TBA+Fe(3+) reactants was significantly reduced with age. Xanthine oxidase (XOD) activity also was markedly increased with age, being more pronounced in the hyperthyroid than in the euthyroid state. The Mn and Cu/Zn superoxide dismutase activities were greater in the hyperthyroid than in the euthyroid state. Glutathione peroxidase activity decreased with age in the euthyroid and, particularly, in the hyperthyroid state. Catalase activity was not affected in the old rats. Concentrations of alpha-tocopherol in the old rats were high in the hyperthyroid state and low in the hypothyroid state, whereas the levels of beta- and gamma-tocopherols in these rats were unchanged in both conditions as compared with the euthyroid state findings. Data suggest that the site of free radical generation differs in older rats, with additional shifts in the location of intracellular lipid peroxidation being noted during hyperthyroidism. Thus, as rats age, the reduction of the free radical scavenger system and the increase in LPO and XOD activities might induce myocardial dysfunction.

Aging↗
PubMed2000

Cell size and oxidative enzyme activity of different types of fibers in different regions of the rat plantaris and tibialis anterior muscles.

The cross-sectional areas and succinate dehydrogenase activities of different types of fibers in different regions of the plantaris and tibialis anterior muscles in 10-week-old male rats were determined using quantitative histochemistry. The muscle fibers were classified as type I, type IIA, or type IIB according to their adenosine triphosphatase activities. There were no regional differences in either the mean cross-sectional area or the mean succinate dehydrogenase activity of type IIA fibers in both muscles. In contrast, type IIB fibers in the deep region of both muscles had smaller cross-sectional areas and higher succinate dehydrogenase activities than those in the superficial and middle regions. These data suggest the presence of regional differences in the cross-sectional area and succinate dehydrogenase activity of type IIB fibers in the muscle.

Adenosine Triphosphatases↗
PubMed2000

Effect of hypobaric hypoxia on rat soleus muscle fibers and their innervating motoneurons: a review.

Mammalian skeletal muscle fibers are classified into three basic types based on their enzyme histochemical profiles: fast-twitch glycolytic (FG), fast-twitch oxidative glycolytic (FOG), and slow-twitch oxidative (SO) types. The type-shift of fibers from FOG to SO in the slow soleus muscle of rats occurs during postnatal growth. Our previous studies have demonstrated that hypoxic exposure inhibits a growth-related type-shift of fibers from FOG to SO in the rat soleus muscle, irrespective of the duration and age at which the animals are exposed to hypoxia. Our previous studies have also revealed that a high percentage of FOG fibers in the soleus muscle of the hypoxia-adapted rats is found only under hypoxic conditions. Furthermore, we have found that these adaptations in fibers of the rat soleus muscle correspond well with those in motoneurons at the ventral horn of the spinal cord that innervate the muscle fibers.

Adaptation, Physiological↗
PubMed2000

Sympathetic fibers innervating the extraocular muscles: cells of origin in the cat superior cervical ganglion.

Cells of origin of sympathetic fibers innervating the extraocular muscles were demonstrated in the cat superior cervical ganglion (SCG) using the horseradish peroxidase (HRP) technique. Each injection of HRP into the muscles was confirmed by labeling in the oculomotor, trochlear and abducens nuclei. In all cases retrogradely labeled neurons were found to be distributed widely to the ipsilateral SCG. Labeled neurons were round or oval in shape and majority of these were medium in size. There were some large-sized neurons which frequently showed to have long dendrites expanding rostrocaudally. The labeling was characterized by localization in the rostral two-thirds of the SCG after HRP injections into the medial, lateral and inferior and superior oblique muscles. However, the labeling was found in the whole of the SCG after HRP injections into the superior rectus and inferior oblique muscles. Compared with our previous studies demonstrating cells of origin of the sympathetic fibers in the facial and hypoglossal nerves, the present experiments showed quite different pattern of distribution of labeled neurons in the SCG.

Adrenergic Fibers↗
PubMed2000

[Mood-congruent effect in self-relevant information processing: a study using an autobiographical memory recall task].

The pattern of the mood-congruent effect in an autobiographical memory recall task was investigated. Each subject was randomly assigned to one of three experimental conditions: positive mood, negative mood (induced with music), and control groups (no specific mood). Subjects were then presented with a word at a time from a list of trait words, which were pleasant or unpleasant. They decided whether they could recall any of their autobiographical memories related to the word, and responded with "yes" or "no" buttons as rapidly and accurately as possible. After the task, they were given five minutes for an incidental free recall test. Results indicated that the mood-congruent effect was found regardless of whether there was an autobiographical memory related to the word or not in both positive and negative mood states. The effect of moods on self-relevant information processing was discussed.

Adult↗
PubMed2000

[Investigation of the resolution and count recovery coefficients of a whole-body PET scanner (Shimadzu SET-2400W) in 2D and 3D mode image].

UNLABELLED: We measured the resolution and count recovery coefficients (RC) of the SET-2400W whole-body PET scanner (Shimadzu Co., Japan) in the 2D and 3D clinical modes. METHOD: The 3D images were reconstructed by using the full 3D image reconstruction method (3-D reprojection algorithm: 3DRP) and the Fourier rebinning method (FORE). The 2D images were reconstructed with conventional filtered back-projection method (FBP). The measurements of resolution and recovery coefficient were according to JRIA (Japan Radioisotope Association) protocols. RESULTS: The transaxial resolutions of all methods were better than 7 mm FWHM at a radius of 10 cm with 1.25 cm-1 cutoff frequency. The average slice width of 2D FBP, 3DRP and FORE are 5.8 mm, 8.0 mm and 6.8 mm respectively at the center of transaxial field of view. The RC values were measured in a range from 10 mm to 27 mm at 6 cm from the center with the cylindrical and spherical hot area phantoms. In all methods, RC values at 27 mm diameter were nearly 1.0 in both type of hot area. RC values at 10 mm diameter in 2D FBP, 3DRP and FORE of cylindrical hot area were 0.69, 0.72, 0.73 and those of spherical hot area were 0.52, 0.51, 0.53 respectively. CONCLUSION: At the SET-2400W, resolution and recovery coefficient of 3D mode image under the clinical mode showed the value which did not differ from the 2D mode image.

Image Processing, Computer-Assisted↗
PubMed2000

Immunohistochemical study on acetaldehyde adducts in alcohol-fed mice.

BACKGROUND: Acetaldehyde binds to some proteins, which results in Schiff base formation. It is assumed that acetaldehyde binds to the proteins after the consumption of ethanol, to form an adduct. Such acetaldehyde adducts are related to organ disease. METHODS: We examined 8-week-old male BALB/c mice, which were given a liquid diet for 7 days. The diet consisted of vitamins, minerals, amino acids, and a 5% (v/v) ethanol solution. After the 7 days, we took tissue samples from the brain, liver, and adrenal cortex to investigate the distribution of acetaldehyde adducts. We performed immunohistochemical staining of the cerebral cortex, liver, and adrenal cortex from the mice by using antibodies against acetaldehyde adducts. RESULTS: Our study showed that acetaldehyde adducts formed in the cerebral cortex in the early phase in alcohol-fed mice. CONCLUSIONS: Because acetaldehyde in the liver has been shown to cause liver damage, our study suggests a relationship between acetaldehyde adducts in the brain and brain damage.

Acetaldehyde↗
PubMed2000

[Intramasseter hemangiomas: a case report].

Intramuscular hemangiomas are uncommon tumours in the head and neck region, especially in the masseter muscle. This article presents a case of a 10-year-old male treated by surgical excision. The authors review the literature to discuss the clinical characteristics, sex, age, differential diagnosis, surgical approaches, and histology.

Child↗
PubMed2000

[Ulegyria].

Explore the source record for details and available documents.

Brain↗
PubMed2000

Nephrotic syndrome due to focal glomerulosclerosis and undifferentiated carcinoma.

In neoplastic disorder-related nephrotic syndrome, focal glomerulosclerosis (FGS) has been reported mainly in hematological disorders like minimal change nephrotic syndrome (MCNS) in association with presumed T lymphocyte dysfunction. The association of FGS with cancer or solid tumor is rare. We report a case of nephrotic syndrome due to FGS in a patient with undifferentiated adenocarcinoma of the cystic duct. Although the underlying mechanism is unclear, the development of FGS seemed to be related to the poor histological differentiation of the cancer in the possibility of production of an active peptide.

Adenocarcinoma↗
PubMed2000

[Ruptured aneurysm of sinus of Valsalva into the right atrium with aortic valve perforation].

A 58-year-old female was admitted to our hospital because of sudden dyspnea and general malaise. A continuous murmur was heard along the left sternal border. A chest X-ray showed cardiomegaly and pulmonary vascular marking. Doppler echocardiography confirmed the presence of an aneurysmatic mass, originating from the non-coronary sinus of Valsalva and extending to the right atrium, with a turbulent flow into the right atrium, aortic regurgitation (II/IV) and tricuspid regurgitation (III/IV). Ascending aortography demonstrated a communication between the aortic sinus and the right atrium. The pulmonary-to-systemic flow ratio was calculated to be 2.04. Oblique aortotomy and right atriotomy were performed. The aneurysm was resected and its origin was directly closed with horizontal mattress sutures through the aortic side and right atrial side. Perforation of a non-coronary cusp that caused aortic regurgitation was found following aortotomy and it was closed with an autologous pericardial patch. Tricuspid annuloplasty was performed using DeVega's technique. The postoperative course was uneventful, and she was discharged on the 10th postoperative day.

Aortic Rupture↗
PubMed2000

[Clinical symptoms and characteristic MR spectroscopic findings in Pelizaeus-Merzbacher disease].

Clinical symptoms and MR spectroscopic findings were studied on 4 cases of Pelizaeus-Merzbacher disease including 1 autopsy case. Common symptoms were severe mental retardation and spastic tetraplegia. These cases had nystagmus, and one had involuntary athetotic movement. Genetical diagnosis revealed in 2 cases, duplication of proteolipid protein (PLP) and deletion in 1, whereas one case had no abnormality of PLP gene. MRI indicated the reversal of signal intensities on T1- and T2-weighed images, a characteristic finding of PMD MR spectroscopy demonstrated a pattern of NAA in 3 cases. This was specific to PMD because other white matter diseases show a decrease in NAA. In conclusion, MRS was useful to differentiate PMD from other white matter diseases.

Adult↗
PubMed1999

Suppression of experimental autoimmune encephalomyelitis by dermatan sulfate.

The effect of dermatan sulfate (DS) on the treatment of Lewis rats with experimental autoimmune encephalomyelitis (EAE) was examined. DS, a sulfated glycosaminoglycan, has been reported to exhibit anticoagulant and fibrinolytic activities. DS treatment (50 mg/kg/day) facilitates recovery from the clinical manifestations of EAE. In this study, the fibrinolytic activity was higher in DS-treated rats than in saline-treated rats. Although the degree of perivascular mononuclear cell infiltration in the spinal cord was not suppressed in DS-treated rats compared to that in saline-treated rats, perivascular fibrin deposition was markedly suppressed in DS-treated rats. These findings suggest that DS would act as an effective therapeutic agent for EAE by preventing fibrin deposition.

Animals↗
PubMed1999

Direct binding of three tight junction-associated MAGUKs, ZO-1, ZO-2, and ZO-3, with the COOH termini of claudins.

ZO-1, ZO-2, and ZO-3, which contain three PDZ domains (PDZ1 to -3), are concentrated at tight junctions (TJs) in epithelial cells. TJ strands are mainly composed of two distinct types of four-transmembrane proteins, occludin, and claudins, between which occludin was reported to directly bind to ZO-1/ZO-2/ZO-3. However, in occludin-deficient intestinal epithelial cells, ZO-1/ZO-2/ZO-3 were still recruited to TJs. We then examined the possible interactions between ZO-1/ZO-2/ZO-3 and claudins. ZO-1, ZO-2, and ZO-3 bound to the COOH-terminal YV sequence of claudin-1 to -8 through their PDZ1 domains in vitro. Then, claudin-1 or -2 was transfected into L fibroblasts, which express ZO-1 but not ZO-2 or ZO-3. Claudin-1 and -2 were concentrated at cell-cell borders in an elaborate network pattern, to which endogenous ZO-1 was recruited. When ZO-2 or ZO-3 were further transfected, both were recruited to the claudin-based networks together with endogenous ZO-1. Detailed analyses showed that ZO-2 and ZO-3 are recruited to the claudin-based networks through PDZ2 (ZO-2 or ZO-3)/PDZ2 (endogenous ZO-1) and PDZ1 (ZO-2 or ZO-3)/COOH-terminal YV (claudins) interactions. In good agreement, PDZ1 and PDZ2 domains of ZO-1/ZO-2/ZO-3 were also recruited to claudin-based TJs, when introduced into cultured epithelial cells. The possible molecular architecture of TJ plaque structures is discussed.

Amino Acid Motifs↗
PubMed1999

Effect of short-term ethanol exposure on the suprachiasmatic nucleus of hypothalamus: immunohystochemical study in mice.

Morphological changes of the suprachiasmatic nucleus (SCN) of the hypothalamus were investigated in mice exhibiting intoxication signs of stages 2 or 3 after a short application term of 6% ethanol. Alterations in glial cells and neurons were examined using anti-glial fibrillary acidic protein (GFAP) and anti-calbindin D28k monoclonal antibody, respectively. The results revealed that short-term ethanol exposure led to strong expression of GFAP-immunoreactivity (GFAP-IR) in the dorsomedial part of the SCN. Furthermore, GFAP-IR astrocytes showed an increase in number and hypertrophy with longer processes. However, calbindin D28k-IR neurons were apparently little changed in the SCN. It is concluded that neuroadaptive response of astrocytes could occur before the neurotoxic effects emerge on neurons on the SCN.

Animals↗
PubMed1999

Proteasome participates in the pathogenesis of ischemic acute renal failure in rats.

Acute renal failure was induced by occlusion of the left renal artery and vein for 45 min followed by reperfusion, 2 weeks after contralateral nephrectomy. Renal function parameters such as blood urea nitrogen, plasma creatinine, creatinine clearance, urine flow and urinary osmolality were measured to test the effectiveness of drugs. Renal function in untreated acute renal failure rats markedly decreased at 24 h after reperfusion. The administration of PSI, N-benzyloxycarbonyl-Ile-Glu(O-t-Bu)-Ala-leucinal, a proteasome inhibitor, at a dose of 1 mg/kg before the occlusion abolished the decreases in the renal function of acute renal failure rats. Calpeptin (1 mg/kg), a calpain inhibitor, attenuated the deterioration of renal function to the same extent as 0.1 mg/kg PSI, but no significant difference was observed between the untreated and calpeptin-treated acute renal failure groups. Histopathological examination of the kidney of untreated acute renal failure rats revealed severe lesions, such as tubular necrosis, proteinaceous casts in tubuli and medullary congestion, all of which were significantly suppressed by PSI (1 mg/kg) treatment. In contrast, calpeptin, at the same dose, was ineffective against the development of renal lesions. These results suggest that proteasome participates in the pathogenesis of ischemic acute renal failure. Thus, proteasome may be a potential target for the identification of agents that may be useful in the treatment of diseases whose etiology is dependent on ischemia/reperfusion.

Acute Kidney Injury↗