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Biomedical subjects

M Itoh

Publications and source records attributed to M Itoh.

At least 991 records · Page 55Linked to original sources
PubMed1987

Haemodynamics and oxygen metabolism in patients after reversible ischaemic attack or minor ischaemic stroke assessed with positron emission tomography.

Regional cerebral blood flow (CBF), blood volume (CBV) and oxygen metabolic rate (CMRO2) were evaluated and compared among normals, patients with recent reversible ischaemic attacks (RIAs) and patients with chronic minor infarction using positron emission tomography. Average CBF together with CMRO2 significantly decreased in the infarction group in the middle cerebral artery territory of the affected hemisphere while the mean values for RIAs were intermediate between the other two groups. CBV also reduced, however it was more preserved compared to flow as seen in decreased CBF/CBV values. Significant interhemispheric difference was found in CBF/CBV ratio, but it did not clearly correlate with OEF changes. Higher OEF was noted only in the restricted brain regions of RIAs where CBF showed large hemispheric asymmetry. However, in other regions, the coupled decline of blood flow and metabolism was found which suggests tissue damage or neuronal cell loss in the brain with previous RIA symptoms.

Adult↗
PubMed1987

Intrahepatic portal-systemic shunt: its etiology and diagnosis.

Four cases of enormous shunt between portal and hepatic veins (portal-hepatic venous shunt) are reported with special reference to sonographic and portographic findings. Ultrasonography, an examination for screening, delineated a snail-like anechoic area in the liver, its connection with the portal and hepatic veins, and marked dilatation of the veins connecting with the shunt. Transarterial or percutaneous transhepatic portography, a method for definitive diagnosis, demonstrated large pooling of the contrast medium flowing from the dilated portal branch and subsequent visualization of the hepatic vein. The etiology and prognosis are unknown at present. The most likely pathogenesis for this shunt seemed to be a congenital anomaly, namely, persistence of the omphalomesenteric venous system. With recent advances in and the more frequent use of real-time ultrasonography, detection of this kind of vascular abnormality will doubtless increase.

Female↗
PubMed1987

Positron emission tomography in minor ischemic stroke using oxygen-15 steady-state technique.

A study with positron emission tomography (PET) was performed on 10 patients with ischemic stroke and mild disability. The patients underwent cerebral angiography, x-ray computed tomography (CT) scan and regional cerebral measurements of CBF, CMRO2, oxygen extraction ratio (OER), and cerebral blood volume (CBV). Only minor arterial involvement was detected by angiography. In all patients, PET images of functional defects were more extensive than the corresponding CT hypodensity, and there were statistically significant reductions in CBF, CMRO2, and CBF/CBV ratio as compared with control subjects. Half of the regions analyzed in the affected hemisphere demonstrated a disruption of the normal coupling between CBF and CMRO2 as reflected by OER values significantly higher or lower than those of the corresponding region of the contralateral hemisphere. The pathophysiological pattern of high OER combined with a reduction in CBF proportionally greater than the reduction in CMRO2 was particularly indicative of regional chronic hemodynamic compromise in these patients.

Aged↗
PubMed1987

Crohn's disease associated with giant inflammatory polyposis.

We found shallow serpiginous, longitudinal ulcerations in the descending colon at the first examination of a 17-year-old female patient with Crohn's disease. Four months later at the second examination, we observed that a polypoid lesion had formed longitudinally in the region of the healed ulcers. The third examination, one year later, showed the presence of pedunculated and semi-pedunculated giant polyps in the descending colon. The lesion of the descending colon was removed surgically to cure the crampy abdominal pain caused by colonic obstruction. The segmental colectomy specimen showed longitudinally aligned pedunculated polyps of various sizes. The pathological diagnosis was inflammatory polyposis. To the best of our knowledge, there have been very few reports on the appearance of a number of pedunculated polyps such as in this case. This reports shows, through endoscopic pictures, the evolution of the polyp and discusses its formation.

Adolescent↗
PubMed1987

Synthesis and biological activities of beta-alanyltyrosine derivative of 2',5'-oligoadenylate, and its use in radiobinding assay for 2',5-oligoadenylate.

beta-Alanyltyrosine derivative of 2',5'-tetraadenylate 5'-triphosphate, pppA2'p5'A2'-p5'A2'p5'A-beta-Ala-Tyr was prepared by coupling of periodate-oxidized pppA2'p5'-A2'p5'A2'p5'A with beta-alanyltyrosine methyl ester, followed by reduction with sodium cyanoborohydride. Its stability to 2',5'-phosphodiesterase and phosphatase was investigated in mouse L cell extract. The 5'-triphosphate of the compound was cleaved gradually to form the 5'-dephosphorylated derivative, A2'p5'A2'p5'A2'p5'A-beta-Ala-Tyr, followed by slow degradation of the 2',5'-phosphodiester bond. On the other hand, pppA2'p5'A2'p5'A2'p5'A was hydrolyzed very quickly under the same conditions. The tetramer derivative bound tightly to the 2',5'-oligoadenylate-dependent endoribonuclease in rabbit reticulocyte lysate or mouse L cell extract and inhibited protein synthesis of mouse L cells more effectively than the unmodified 2',5'-tetraadenylate 5'-triphosphate. The corresponding trimer derivative had slightly weaker activities than the unmodified trimer for binding to the endoribonuclease and for inhibition of protein synthesis. The compound, pppA2'p5'A2'p5'-A2'p5'A-beta-Ala-Tyr, was iodinated easily at the tyrosine residue with 125I, giving a high-specific-radioactivity derivative which was used as a radio-labeled probe in a radiobinding assay for 2',5'-oligoadenylate.

Adenine Nucleotides↗
PubMed1987

Single amino acid substitution of Sendai virus at the cleavage site of the fusion protein confers trypsin resistance.

Amino acid sequences of fusion (F) proteins of two trypsin-resistant mutants of Sendai virus, TR-2 and TR-5, were deduced from nucleotide analysis of cDNA encoding the F gene and were compared with that of the trypsin-sensitive wild-type Sendai virus. In both mutants, amino acid substitutions were found at residues 116 (Arg----Ile), the cleavage site of the F protein, and 109 (Asn----Asp). Two trypsin-sensitive revertants, TSrev-52 and TSrev-58, derived from TR-5 were both activated by trypsin similarly to the wild-type virus and had a single amino acid reversion from Ile to Arg at residue 116, leaving Asp as before at residue 109. These results indicate that the trypsin sensitivity of Sendai virus can be changed by a single amino acid substitution at the cleavage site of the F protein and a mutation from Arg to Ile is responsible for the acquisition of resistance to trypsin.

Amino Acid Sequence↗
PubMed1987

Serum and urinary estrone sulfate during the menstrual cycle, measured by a direct radioimmunoassay, and fate of exogenously injected estrone sulfate.

Serum and early-morning urinary levels of estrone sulfate during the menstrual cycle were measured by a direct radioimmunoassay without hydrolysis. These levels were high and showed prominent peaks [serum, 2.67 +/- 0.37 ng/ml (mean +/- SE); urine, 5.82 +/- 2.3 micrograms/l] around the day of the preovulatory estradiol-17 beta peak, and increased again during the luteal phase. Following intravenous injection of estrone sulfate, serum estrone sulfate, estrone and estradiol-17 beta were measured. The conversion of estrone sulfate to estrone and/or estradiol-17 beta was very small during their transit in the general circulation.

Adolescent↗
PubMed1987

Immunoreactive epidermal growth factor in mouse digestive organs. Use of a sensitive enzyme immunoassay.

A sandwich enzyme immunoassay (ELISA) system for mouse epidermal growth factor (EGF), which has a high sensitivity (500 fg/tube), has been established. It makes it possible to measure minute amounts of immunoreactive EGF in various mouse tissue without pretreatment. The immunoreactive EGF concentrations in digestive tissues of adult mice were much lower than previously reported. A significant sex difference was detected not only in the submandibular gland, but also in the oesophagus and forestomach. Although sialoadenectomy decreased the immunoreactive EGF contents in the alimentary tract to 4.2-23.8% of the pre-operative levels, the duodenal immunoreactive EGF was unaffected. Positive immunostaining was observed in the submandibular and sublingual gland, but not in the other digestive tissues, including the duodenum. These data implied that most of the EGF in the digestive tissues was derived mainly from the saliva and that a small amount of endogenous EGF existed in the duodenum. The physiological role of exogenous salivary EGF in the alimentary tract and the origin of endogenous duodenal EGF are discussed.

Animals↗
PubMed1987

Reorganization of thymic microenvironments during development and lymphomagenesis.

Modulation of thymic microenvironments during ontogeny and lymphomagenesis in mice was studied with two rat monoclonal antibodies (moAb) which recognized distinct subpopulations of thymic epithelial reticular cells (TER). In adult thymus, the TER subpopulation stained by moAb B6TS-1 was localized in the subcapsular zone, cortico-medullary junction, and medulla. In fetal thymus, it was initially distributed throughout the rudiment, but after day 16 of gestation, it was rapidly redistributed to the locations seen in adult thymus. From an early stage of thymic lymphomagenesis, the TER bearing mB6TS-1 (epitope defined by moAb B6TS-1) in the cortico-medullary junction, in particular those associating with small blood vessels, proliferated and formed a characteristic network throughout the thymus, in which numerous growing lymphoma cells were entrapped. On the other hand, moAb AKTS-1 stained another TER subpopulation that was localized in the cortex in both fetal and adult thymus. Unlike mB6TS-1+ TER, mAKTS-1+ TER became increasingly sparser during lymphomagenesis. Selective proliferation of the mB6TS-1+ TER subpopulation in the cortico-medullary junction was seen in spontaneous, radiation-induced, and chemical-induced mouse thymic lymphomas. The possible biological significance of such modulation of thymic microenvironments in the natural history of lymphomagenesis is discussed.

Animals↗
PubMed1987

Positron tomography for ophthalmology.

Positron emission tomography (PET) has been applied so far to estimate the viability of malignant tumors or to assess cerebral higher function in living animals and in man. Our preliminary results suggested possibilities of nontraumatic imaging diagnosis of orbital tumors; the rate of incorporation of glucose analogue, 18F-2-fluorodeoxyglucose, seemed to reflect the malignant nature of the tissue. PET also gives information concerning regional blood flow, glucose metabolism and oxygen consumption in the brain. We demonstrated chronic cerebral ischemia in cases with rubeosis iridis. PET was more sensitive in detecting lesions responsible for cortical hemianopsia than X-ray computed tomography (CT) and magnetic resonance CT.

Aged↗