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Biomedical subjects

M Itoh

Publications and source records attributed to M Itoh.

At least 199 records · Page 11Linked to original sources
PubMed2000

Development of full-length Trk B-immunoreactive structures in the prefrontal and visual cortices of the macaque monkey.

Distribution and morphological changes of cells containing the signal transducing neurotrophin receptor, full-length Trk B (fl-Trk B), were investigated in the prefrontal cortex (area FD) and the primary visual cortex (area OC) of the macaque monkey between embryonic day 140 and the adult stage. In area FD at the adult stage, fl-Trk B immunoreactivity was mainly observed in the pyramidal cells in layers II/III, V and VI. Small numbers of granule cells in layer IV were immunopositive. Bipolar and multipolar cells in layer II were rarely immunoreactive. At embryonic day 140, the number of fl-Trk B immunoreactive pyramidal cell was high, and gradually decreased until the adult stage. In layer IV, the number of fl-Trk B-ir cells was also high at embryonic day 140, and decreased remarkably from postnatal day 7 to the adult stage. On the other hand, in area OC at the adult stage, cells in layers II/III, IV, V and VI were fl-Trk B immunopositive. From embryonic day 140 until adulthood, the cells in layer IVc were fl-Trk B immunoreactive. The strongest fl-Trk B immunoreactivity in areas FD and OC occurred at postnatal month 6, coinciding with the time of the synapse overproduction. These findings suggest that ligands of fl-Trk B, such as BDNF and NT4/5 may be involved in the development and maintenance of the monkey cerebral cortices.

Animals↗
PubMed2000

Popliteal amyloidoma presenting with leg ischemia in a chronic dialysis patient.

The authors report a case of bilateral popliteal amyloidoma causing stenosis of the popliteal artery and vein. This patient had been treated with hemodialysis for 26 years. The diagnosis was made with MR angiography. A popliteal tumor of the right knee was resected surgically and the histologic examination showed deposition of amyloid. After resecting the popliteal tumor, the severe leg pain and intermittent claudication improved. This report suggests that popliteal amyloid tumors should be considered in a patient undergoing long-term hemodialysis who complains of leg pain and intermittent claudication.

Adult↗
PubMed2000

Association of osteopontin with ischemic axonal death in periventricular leukomalacia.

Osteopontin (OPN) is a bone matrix protein expressed my macrophages and related to the process of tissue calcification, and is also known to protect ischemic cells. To understand how OPN is involved in the process of ischemic axonal death in periventricular leukomalacia (PVL), we examined the immunoreactivity of OPN and ionized calcium binding adaptor molecule 1 (Iba1; microglia/macrophage marker) at various stages of PVL. OPN immunoreactivity paralleled the number of Iba1-positive foam cells; a finding which suggests the production of OPN protein by foam cells. OPN immunoreactivity was not found in either normal white matter or acute PVL lesions, but was detected at the subacute and chronic stages in swollen and calcified axons bordering the ischemic zone. These findings suggest that OPN is closely associated with death of swollen axons at the periphery of the ischemic zone, regulating the presence or absence of calcification.

Axons↗
PubMed2000

A novel migration-related gene product, doublecortin, in neuronal migration disorder of fetuses and infants with Zellweger syndrome.

Immunohistochemical expression of doublecortin (DCX), KIAA0369 (KIA) and LIS1 proteins as well as nestin and vimentin in the cerebral cortices of six patients with Zellweger syndrome (ZS), aged 19 gestational weeks (GW) to 8 months, was compared with that in nine controls, aged 12 GW to 8 months. DCX immunoreactivity was apparently reduced in ZS, particularly in the cortical plate of fetuses, and in the subependymal foci of heterotopic neurons of the infants. Reduced expression of DCX in ZS was confirmed by Western blot analysis. On the other hand, neuronal expression of nestin was high in the cortical plate, migrating cells of the white matter and germinal cells in the ventricular zone in fetuses with ZS. Immunoreactivities for KIA, LIS1 and vimentin in ZS were comparable to those of controls. Reduced expression of DCX may be responsible for the neuronal migration disorder, and increased expression of nestin may be another evidence for delayed neuronal maturation in ZS.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2000

Glucose uptake by individual skeletal muscles during running using whole-body positron emission tomography.

The purpose of this study was to examine, by positron emission tomography (PET), the distribution of [18F]fluoro-deoxy-glucose ([18F]FDG) uptake by human muscles during 35 min of running. Thirteen healthy male subjects were studied, seven of whom participated in the exercise study. Running intensity was kept constant such that the subjects' heart rates were maintained at between 140 and 150 beats per minute. [18F]FDG [62.9 (14.8) MBq, mean (SD)] was injected after 15 min of running. PET imaging was started immediately after the running ended. The ratio of [18F]FDG uptake by muscles in runners to that in control subjects (r-c ratio) varied from three to six for the muscles of the foot and leg below the knee joint. The r-c ratio of the medial head of the gastrocnemius (MG) was higher than that of its lateral head (LG). The r-c ratio of the rectus femoris (RF) was lower than that of the other three muscles of the quadriceps femoris (QF). The r-c ratio of inactive muscles located above the waist was approximately 0.7. These results suggest that, during the moderate running of this study: (1) glucose uptake by muscles of the foot and leg below the knee joint clearly increases, (2) the r-c ratio differs significantly among the skeletal muscles, which act synergistically, and (3) glucose uptake by inactive skeletal muscles decreases.

Fluorodeoxyglucose F18↗
PubMed2000

Total arch replacement with an aortic arch aneurysm due to chronic interstitial pneumonia: report of a case.

The case of a 66-year-old man who had rheumatoid arthritis, chronic interstitial pneumonia (IP) with honeycomb lung, and an aortic arch aneurysm is described. He complained of left chest pain in April 1998 and chest computed tomography revealed an enlargement of a thoracic aneurysm whose maximum diameter reached 7 cm. He was urgently transferred to our institution to undergo immediate surgery for an impending rupture of the aneurysm. His PaO2 with 80 Torr with oxygen therapy. The operation included a median sternotomy, extracorporeal circulation with selective cerebral perfusion, the use of cold blood cardioplegic solution, and open distal anastomosis. Although an acute exacerbation of IP occurred 2 months after the surgery, he successfully received intensive care including high-dose steroid therapy and artificial ventilation. He was successfully weaned from the ventilator and is now being followed up with medical treatment.

Aged↗
PubMed2000

Scavenging effect of nicorandil on free radicals and lipid peroxide in streptozotocin-induced diabetic rats.

Free radicals and lipid peroxide (LPO), easily formed in the diabetic state, play an important role in the development of diabetic complications. Potentially, nicorandil may reduce the production of free radicals and LPO in various organs. In fact, increased LPO levels in the serum, kidney, and cardiac muscle of diabetic (DM) rats were reduced by nicorandil treatment (N treatment). Xanthine oxidase (XOD), which produces free radicals, was decreased in the liver and increased in the kidney of DM rats compared with control rats, and these changes were prevented by N treatment. The concentration of Cu, Zn-superoxide dismutase (SOD) decreased in the cardiac muscle and increased in the kidney of DM rats, and these changes returned to normal after N treatment. The decreased concentration of Mn-SOD in the liver, kidney, and cardiac muscle from DM rats was also reversed by N treatment. The changes in catalase and glutathione peroxidase (GSH-PX) activities in DM rats were not improved effectively by N treatment. Another K-adenosine triphosphate (K-ATP) channel opener, tilisolol hydrochloride, had an effect similar to that of nicorandil. The effects of nicorandil and tilisolol were studied only in DM rats. These data imply that N treatment, as an antioxidative therapy, may be beneficial in preventing diabetic complications due to lipoperoxidation and free radicals in DM rats.

Animals↗
PubMed2000

Sesquiterpenoids from Ferula kuhistanica.

Methanol extracts of the air-dried roots and stems of Ferula kuhistanica afforded seven daucane-type sesquiterpenes, called kuhistanicaol A-G, together with 13 known daucane esters. Their structures were established on the basis of spectroscopic evidence and the results of chemical reactions.

Apiaceae↗
PubMed2000

Coumarins and bicoumarin from Ferula sumbul: anti-HIV activity and inhibition of cytokine release.

The methanol extract of the dried roots of Ferula sumbul afforded two furanocoumarin esters, fesumtuorin A, B, one bicoumarin, fesumtuorin C, five spirobicoumarins, fesumtuorin D, E, F, G and H, along with nineteen known coumarins. Their structures were established on the basis of spectroscopic studies. Some of the isolated compounds showed anti-HIV activity and very weak inhibition of cytokine release.

Anti-HIV Agents↗
PubMed2000

Histamine H(1) receptors in patients with Alzheimer's disease assessed by positron emission tomography.

Cerebral histamine H(1) receptor binding was measured in vivo in 11 normal subjects (six young and five old) and 10 patients with Alzheimer's disease by positron emission tomography and [11C]doxepin, a radioligand for H(1) receptors. The parametric images describing the tracer kinetics were generated by either compartmental or graphical analysis, and were examined statistically on region-of-interest and voxel-by-voxel bases. The binding potential of H(1) receptors showed a significant decrease particularly in the frontal and temporal areas of the Alzheimer's disease brain compared to the old, normal subjects. In addition, the receptor binding correlated closely to the severity of Alzheimer's disease assessed by the Mini-Mental State Examination score within several brain areas. The ratio of K1 values between the brain areas and the cerebellum was used as a relative measure of regional cerebral blood flow which decreased in the frontal and temporal areas of the Alzheimer's disease brain. However, the difference in the binding potential (total concentration of receptor/equilibrium dissociation constant) between the Alzheimer's disease patients and the old, normal subjects was greater than that in the cerebral blood flow, and the rate of decrease in the binding potential with the progression of Alzheimer's disease was greater than the rate of decrease in the cerebral blood flow. This study reveals the predominant disruption of the histaminergic neurotransmission in the neurodegenerative processes of Alzheimer's disease. This study suggests that the decline of the histamine receptor binding might play a substantial role in the cognitive deficits of Alzheimer's disease patients.

Adult↗
PubMed2000

Glutamate transporters in neonatal cerebellar subarachnoid hemorrhage.

We have previously described the immunoreactivities of glutamate transporters, EAAT4 and GLAST, in the developing human cerebellum. In the present report, we demonstrate the different expression of EAAT4 and GLAST in the pathologic condition, neonatal subarachnoid hemorrhage. EAAT4 and GLAST were characteristically disturbed in the cerebellar cortices beneath the subarachnoid hemorrhage. In preterm infants with subarachnoid hemorrhage the decrease in EAAT4 immunoreactivity was more prominent than in term infants, and GLAST immunoreactivity in the inner granular cell layer decreased and reappeared later than in term infants with subarachnoid hemorrhage. Although Bergmann's glia removes glutamate from the extracellular space surrounding Purkinje cells in the early stage of hypoxic-ischemic brain damage, the reaction of EAAT4 and GLAST in the cerebellar cortex under the subarachnoid hemorrhage was decreased, and immature glia had a delayed reaction. These characteristics of glutamate transporters in immature cells may lead to cell death and olivocerebellar degeneration.

ATP-Binding Cassette Transporters↗
PubMed2000

Dopamine transporter and nitric oxide synthase in hypoxic-ischemic brain.

Changes in dopamine transporter and neuronal nitric oxide synthase (nNOS) were investigated by immunohistochemistry in 18 cases of hypoxic-ischemic basal ganglia necrosis. Neuropil dopamine transporter immunostaining in the striatum was increased in seven cases, with relatively mild basal ganglia necrosis, and decreased in four cases, with marked basal ganglia necrosis, compared with age-matched control subjects. Correspondingly, some striatal neurons had increased immunoreactivity to dopamine transporter in the cases of increased immunostaining in the neuropil. nNOS-positive neurons did not obviously change in cases of basal ganglia necrosis within 2 days after birth and then decreased or were not detectable in cases of basal ganglia necrosis at more than 3 days after birth. The results suggest that the synthesis of dopamine transporter is up-regulated in relatively mild basal ganglia necrosis to compensate for the uptake of increased dopamine, that this compensative ability is lost in marked basal ganglia necrosis, and that nNOS-containing neurons in the striatum are relatively resistant to hypoxic ischemia. We speculate that glutamate excitotoxicity mediated by glutamate receptors 1, 2/3, and 4 and excessive dopaminergic excitatory activity may play important roles in hypoxic-ischemic basal ganglia necrosis and that nNOS does not contribute to that condition.

Basal Ganglia Diseases↗
PubMed2000

Correlation between cerebrovascular maturity and periventricular leukomalacia.

This study disclosed the close correlation between the characteristic developmental change of human cerebral vessels and the occurrence of periventricular leukomalacia (PVL), as judged by anticollagen type 6 immunohistochemical analysis. The earlier appearance of collagen type 6-positive vessels in the deep white matter supports the concept that the medullary vein, a terminal branch of the internal cerebral vein, develops earlier than the cortical and subcortical veins and the perforating artery because the latter was not stained in early gestation. In cases with an old lesion of PVL the distribution of the lesions with abnormal vessels differed with gestation age. These results suggest that its distribution correlates with the development of perforating medullary arteries. Thus a discrepancy between the arteries, revealing slow maturation, and veins, revealing early maturation, in the deep white matter may be an important predisposing factor for PVL. Furthermore, the widespread lesions of PVL may be closely related to the involvement of transcortical tract damage, in terms of specific motor or intellectual disabilities.

Brain↗
PubMed2000

Dissection of signaling cascades through gp130 in vivo: reciprocal roles for STAT3- and SHP2-mediated signals in immune responses.

We generated a series of knockin mouse lines, in which the cytokine receptor gp130-dependent STAT3 and/or SHP2 signals were disrupted, by replacing the mouse gp130 gene with human gp130 mutant cDNAs. The SHP2 signal-deficient mice (gp130F759/F759 were born normal but displayed splenomegaly and lymphadenopathy and an enhanced acute phase reaction. In contrast, the STAT3 signal-deficient mice (gp130FXQ/FXXQ) died perinatally, like the gp130-deficient mice (gp130D/D). The gp130F759/F759 mice showed prolonged gp130-induced STAT3 activation, indicating a negative regulatory role for SHP2. Th1-type cytokine production and IgG2a and IgG2b production were increased in the gp130F759/F759 mice, while they were decreased in the gp130FXXQ/FXXQ immune system. These results indicate that the balance of positive and negative signals generated through gp130 regulates the immune responses.

Acute-Phase Reaction↗
PubMed2000

Cleavage of Bax-alpha and Bcl-x(L) during carboplatin-mediated apoptosis in squamous cell carcinoma cell line.

Although carboplatin (CBDCA) has been used for the treatment of several types of tumors, the complete response rate has been limited, probably because of inherent or CBDCA-induced resistance. As a first step to overcome these problems, we tried to elucidate the mechanisms of CBDCA-mediated cytotoxicity in the squamous cell carcinoma cell line MIT7. The treatment of cells with CBDCA resulted in apoptosis in a dose-dependent manner, as assessed by the propidium iodide staining method and DNA degradation in a nucleosomal pattern. The induction of apoptosis was accompanied by the decline of mitochondrial membrane potential (Deltapsi(m) ) at 12 h following CBDCA stimulation. Variant forms of p18 Bax-alpha and p16 Bcl-x(L) were generated with the down-regulation of both Bax-alpha (p21) and Bcl-x(L) (p31) at 36 and 48 h following CBDCA stimulation, suggesting that the modulation of Bcl-2 family proteins Bax-alpha and Bcl-x(L) play some role in CBDCA-mediated apoptosis. The activation of caspase-3 and -8 occurred at 12 and 24 h following the stimulation, respectively. The pretreatment of cells with pan-caspase inhibitor Z-VAD-fmk markedly prevented CBDCA-mediated cytotoxicity/apoptosis and the modulation of Bcl-2 family proteins (generation of p18 Bax-alpha and p16 Bcl-x(L) ) with only slight prevention of decline of Deltapsi(m). Taken together, these results may suggest that activation of several caspases, including caspase-3 and -8, plays some role in CBDCA-mediated apoptosis, probably through the modification of Bcl-2 family proteins, Bax-alpha and Bcl-x(L). Moreover, caspase activation may occur downstream of membrane depolarization.

Antineoplastic Agents↗
PubMed2000

Sesquiterpene coumarins and related derivatives from Ferula pallida.

Six new compounds-two sesquiterpene coumarins, pallidones A and B (1, 2), and four related derivatives, pallidones C-F (3-6), as well as two known sesquiterpene coumarins, feselol (7) and conferol (8), have been isolated from the EtOAc extracts of the roots of Ferula pallida. All structures of these compounds were determined on the basis of spectral evidence, especially 2D NMR ((1)H-(1)H COSY, HSQC, HMBC, and NOESY) and HRMS. The possible biosynthetic pathway of pallidones C-F (3-6) is discussed.

Coumarins↗
PubMed2000

Prenylated benzoic acid derivatives from Ferula kuhistanica.

Four new prenylated benzoic acid derivatives, kuhistanols A-D (1-4), along with one known compound, 3-farnesyl-p-hydroxybenzoic acid (5), have been isolated from the roots of the Uzbekistan medicinal plant, Ferula kuhistanica. Their structures were established on the basis of chemical and spectral evidence. Compound 4 showed a significant inhibitory effect on cytokine production in lipopolysaccharide-stimulated human peripheral mononuclear cells.

Apiaceae↗