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Biomedical subjects

M Itoh

Publications and source records attributed to M Itoh.

At least 955 records · Page 53Linked to original sources
PubMed1989

[NMR spectroscopy of tumors].

Nuclear Magnetic Resonance Spectroscopy provides a non-invasive method for monitoring tumor bioenergetics and response to therapy. The 31 P spectrum appears to be an indicator of tumor bioenergetics, reflecting its extent of perfusion and degree of oxygenation. During growth, the level of high energy phosphates generally decreased while the level of low energy phosphates generally increased. This has been attributed to the development of vascular insufficiency. Tumor responses to chemotherapy, radiation therapy and hyperthermia appear to be accompanied by significant 31 P spectral changes. Specific metabolic pathways have been examined by 13 C NMR studies employing isotropically labeled metabolites. Detection of 1H compounds holds considerable promise for application to experimental, clinical oncology.

Cobalt Radioisotopes↗
PubMed1989

HTLV-1 rex and HIV-1 rev act through similar mechanisms to relieve suppression of unspliced RNA expression.

Human retroviruses, human T cell leukemia viruses (HTLV) and human immunodeficiency viruses (HIV), express two classes of mRNAs; fully spliced mRNA in the early phase and intron-containing mRNA in a later phase. The expressions of HTLV-1 rex and HIV rev by early mRNAs are essential for the later phase of expression of intron-containing gag and env mRNAs. Each two cis-acting sequences seem to be involved in these regulations: HTLV-1 rex depends on a splice donor (SD) and a responsible element (RXE) at the 3' end, whereas HIV rev depends on a specific repressive sequence (CRS) and a responsible element (RRE) in the intron, but does not require an SD. For analyses of these cis-acting sequences, we inserted an HIV element RRE into an HTLV-1 construct and tested the responses to HTLV-1 rex and HIV rev regulations. The results indicated that both rex and rev could regulate RNA expression of these chimeric constructs responding to an HIV RRE. A repressive element (CRS) was dispensable, and the intronic or exonic location of RRE was not important. These observations suggest that rex and rev could be functionally equivalent to induce cytoplasmic expression of unspliced RNA which expression is suppressed either by an SD or CRS depending on the construction.

Cell Line↗
PubMed1989

Quantitative evaluation of L-[methyl-C-11] methionine uptake in tumor using positron emission tomography.

Tumor uptake of L-[methyl-11C]methionine ([11C]Met) was assessed in six patients with brain tumors and three patients with lung cancer using positron emission tomography (PET). In arterial plasma samples taken at 5, 15, 30, and 60 min after injection, a fraction of [11C]Met was measured using high performance liquid chromatography in individual patients. Employing curve fitting, a history of [11C]Met activity was obtained as an input function. By means of sequential PET scannings and graphic analysis, uptake rate and distribution volume of [11C]Met in tumor tissue were calculated. In two studies irreversible uptake into the tumors was not seen when total plasma 11C activity was used as the input; however when [11C]Met plasma activity was used, definite irreversible uptake was seen, indicating tumor viability. In other studies, up to 24% underestimation of uptake rate was found. The present results demonstrated the importance of measuring [11C]Met in plasma for quantitative assessment of in vivo amino acid metabolism in tumors.

Adolescent↗
PubMed1988

A study of the late effects of radiotherapy and operation on patients with maxillary cancer. A survey more than 10 years after initial treatment.

One hundred seventy-one maxillary carcinoma patients who survived more than 10 years after initial treatment were surveyed. Performance status was unrestricted in 35.1% of the patients, slightly restricted in 34.5%, moderately restricted in 21.1%, restricted in 7.0%, and very restricted in 2.3%. Radiation-induced cataracts on the affected side occurred in 100% of the patients treated with radiation. Good visual acuity was maintained in only 65.8% of the patients, even on the contralateral side. Fifty-five percent of the patients retained symmetric facial animation due to our policy of conservative therapy. Restricted mouth opening occurred in 32.2% of the patients, taking liquid diet in 21.1%, and middle ear effusion in 26.3%, which were closely linked to maxillectomy operation. This study suggests that avoiding excess radiation dosage, strict control of radiation field, adaption of two portals with 60 grades wedge pair filter, use of appropriate protectors, limiting removal at the maxillactomy, and postoperative care for trismus or tympanic effusion are necessary.

Combined Modality Therapy↗
PubMed1988

Zinc content in discrete hippocampal and amygdaloid areas of the epilepsy (El) mouse and normal mice.

In the present study, zinc content was determined in discrete hippocampal and amygdaloid areas of 3 strains of mice (El, ddY and CBA) using an atomic absorption spectrophotometer. Zinc content was significantly lower in the dentate area of El strain compared to ddY and CBA strains. The El mouse is considered an animal model for epilepsy and the seizures in this mouse appear to originate in the hippocampus. The results suggest the possible involvement of hippocampal zinc in the pathophysiology of convulsive seizures in the epileptic mouse.

Amygdala↗
PubMed1988

Possible mechanism of inhibition of experimental pulmonary metastasis of mouse colon adenocarcinoma 26 sublines by a sialic acid: nucleoside conjugate.

As described previously (I. Kijima-Suda et al., Cancer Res., 46: 858-862, 1986), a sialyltransferase inhibitor, 5-fluoro-2',3'-isopropylidene-5'-O-(4-N-acetyl-2,4-dideoxy-3,6,7,8-tetra -O- acetyl-1-methoxycarbonyl-D-glycero-alpha-D-galactooctapyranosyl)ur idine (KI-8110), inhibits pulmonary metastasis of murine colon adenocarcinoma 26 sublines of high (NL-17) and low (NL-44) metastatic potential. To investigate the mechanism of this inhibition, the effect of KI-8110 on the metastatic cascade, especially on the interaction between tumor cells and platelets which may play a crucial role in tumor cell metastasis, was examined. NL-17 cells induced irreversible platelet aggregation in heparinized human platelet-rich plasma in vitro. This activity was reduced by pretreatment of the tumor cells with KI-8110. Inhibition of aggregation was also induced by the treatment of tumor cells with neuraminidase or Limax flavus agglutinin, a lectin specific for sialic acid. Sialic acid, fucose, sialyllactose, and bovine submaxillary mucin inhibited this tumor cell-induced platelet aggregation, while galactose, mannose, lactose, alpha 1-acid glycoprotein, fetuin, and asialo-bovine submaxillary mucin did not. KI-8110 also inhibited platelet-derived growth factor-dependent growth of NL-17 cells, but showed no effect on insulin or epidermal growth factor-dependent growth of the tumor cells. Platelet-derived growth factor-induced phosphorylation of membrane protein was reduced by treatment of NL-17 cells with KI-8110. The same result was obtained in the neuraminidase-treated membrane fraction of NL-17 cells. These results suggest that KI-8110 inhibits experimental tumor cell metastasis by inhibiting the interaction between tumor cells and host platelets in at least two pathways, and this may be due to a reduction of sialic acid contents of the membrane surface of tumor cells.

Animals↗
PubMed1988

Regional coupling of blood flow and methionine uptake in an experimental tumor assessed with autoradiography.

Regional distribution of L-[methyl-14C] methionine (14C-MET) and 4-[18F] fluoro-antipyrine was compared using experimental rat tumors (AH109A) and a computerized autoradiogram image processor. Tissue distributions of the two tracers were found to be inhomogeneous in the tumor with nearly identical image patterns. Analysis of tissue radioactivities revealed that 82% of 14C-MET was derived from the acid insoluble fraction at 60 min after injection. The present study showed that 14C-MET uptake closely relates to tissue blood flow and may depend on its blood to tissue transport. Rapid incorporation of MET in the acid insoluble fraction implies that it is rapidly metabolized after transport into tumor tissue.

Animals↗
PubMed1988

The distribution of hypoglossal motoneurons in the dog, rabbit and rat.

The distribution of motoneurons innervating the extrinsic tongue muscles was studied in the dog, rabbit and rat using the horseradish peroxidase technique. In these mammals, hypoglossal motoneurons were clustered in roughly ventral (or medial) and dorsal (or lateral) groups. Axons of hypoglossal motoneurons in the ventral (or medial) group passed via the medial branch of the hypoglossal nerve, and those in the dorsal (or lateral) group by way of the lateral branch of the hypoglossal nerve. Motoneurons supplying the geniohyoid or genioglossus muscle were distributed, respectively, in the ventral or lateral aspect of the ventral (or medial) cluster of hypoglossal motoneurons. Hypoglossus and styloglossus motoneurons were located in the lateral aspect of the dorsal (or lateral) cluster. The area of distribution of hypoglossus motoneurons overlapped with that of styloglossus motoneurons. It seems likely that motoneurons innervating intrinsic tongue muscles form the remainder of the hypoglossal nucleus. The largest motoneurons in the hypoglossal nucleus were distributed in the cluster of geniohyoid motoneurons. Thus, in the present study a somatotopic arrangement of motoneurons innervating the extrinsic tongue muscles was found, in keeping with previous studies using the retrograde cell degeneration technique.

Animals↗
PubMed1988

Positron CT imaging of an impending stroke.

We present PET findings of a case of a transient ischemic attack which later progressed to cerebral infarction. Cerebral blood flow at the stroke focus in the right parietal cortex measured after a TIA attack and before stroke was as low as 24 ml/100 g/min with some increase in oxygen extraction fraction and blood volume. The condition was compatible with "misery perfusion". This case may be an example suggestive that the "misery perfusion sign" is a warning of impending stroke and its poor prognosis if left without appropriate treatments.

Aged↗
PubMed1988

A large inferior mesenteric-caval shunt via the internal iliac vein.

A large portosystemic shunt between the inferior mesenteric vein and the right internal iliac vein in a 28-yr-old non-cirrhotic man is presented. This collateral was discovered by ultrasound done as a screening examination for gastrointestinal bleeding. The direct communication of the inferior mesenteric vein with the internal iliac vein was demonstrated by computed tomography and percutaneous transhepatic portography. Surgical ligation of the collateral, performed to prevent future portosystemic encephalopathy, resulted in reduction of serum ammonia level and cessation of long-standing hemorrhoidal bleeding.

Adult↗
PubMed1988

Interferon gamma modulates the ability of autologous non-T cells to stimulate T cells to produce and respond to interleukin 2.

The interactions of T-cell receptor with self-Ia antigen on non-T cells induced IL-2 production and IL-2 receptors on the cell surface and thus responsiveness to IL-2 of T cells in autologous mixed-lymphocyte reaction (AMLR). Four-day-cultured autologous non-T cells lost their ability to stimulate T cells to produce and respond to IL-2 with concurrent decrease of HLA-DR and HLA-DQ antigen expressed on the cell surface. Culturing of non-T cells with 500 U/ml of recombinant interferon gamma (IFN-gamma) maintained their stimulating ability which was otherwise lost. Treatment of non-T cells with monoclonal anti-HLA-DR or anti-HLA-DQ antibody before mixture with T cells abrogated their ability to induce IL-2 production and IL-2 responsiveness of T cells. The combined data suggested that Ia antigen expressed on non-T cells is modulated by IFN-gamma, which increases the ability of non-T cells to stimulate autologous T cells to produce and respond to IL-2.

Cell Communication↗
PubMed1988

Internal representations and the conceptual operation of color in pure alexia with color naming defects.

This research examined the structure of internal representation and the conceptual operation of color in two pure alexic cases (Case I and Case II) with color naming defects. Experiment I investigated the structure of the internal representation of different kinds of colors using a similarity judgment task. Experiment II examined categorical judgments of perceived colors using a two-alternative-forced choice task. Experiment III tested the classification of perceived colors using a color sorting task. The performance of Case I essentially fell within the normal range while the results of Case II showed some impairment in the conceptual operation of color. Analysis of the responses obtained from these experiments indicated that the color naming defects in Case I can be explained in terms of visual-verbal disconnection. However, the naming defects in Case II reflect disfunction in some other higher cortical processes coupled with visual-verbal disconnection.

Color Perception↗
PubMed1988

A simple sternal turnover procedure using a vascular pedicle for a funnel chest.

We have improved the sternal turnover surgical procedure by using a vascular pedicle for a funnel chest. Rather than performing a simple sternal turnover, we thought it better to use the sternum with the vascular pedicle attached, anticipating that this would lead to fewer postoperative complications and a more desirable result. The following method for performing the operation was devised: (1) cutting the deformed sternum at the second intercostal position; (2) cutting the second costal cartilages to allow a repositioning of the vascular pedicle onto the presternal surface; (3) turning the sternum over, placing one end on the other, and attaching one end to the other; and (4) making a groove in the turned-over sternum to prevent the decussated vascular pedicle from becoming constricted. By using this method, it is easily possible to keep the bilateral internal thoracic vessels intact. We used this surgical technique on a 17-year-old boy and obtained very favorable results.

Adolescent↗
PubMed1988

Experimental and clinical studies on epidermal growth factor for gastric mucosal protection and healing of gastric ulcers.

In experimental studies, 0.6 N HCl-induced gastric mucosal injury was significantly severe in submandibularectomized rats (SMR rats) than that in either SMR rats receiving exogenous mouse EGF (SMR + EGF rats) or controls. This was also true in gastric injury induced by 0.4 N HCl under pretreatment with indomethacin to reduce gastric mucosal prostaglandins (PGs). Somatostatin (SLI), PGE2, and PAS-stained mucus in the corpus were significantly reduced in SMR rats in comparison to SMR + EGF and control rats. In clinical studies, salivary EGF secretion was much higher in peptic ulcer patients than healthy controls. beta-Urogastrone was effective in the treatment of gastric ulcers. On the basis of experimental studies, we conclude that the protective effect of EGF on the gastric mucosa is, in part, mediated indirectly by increases in SLI, PGE2, and mucus production. However, endogenous, as well as exogenous, EGF has an important direct, cytoprotective effect on the gastric mucosa. From the clinical studies, we also conclude that salivary EGF secretion in ulcer patients increases in a homeostatic response to the presence of an ulcer, facilitating ulcer healing. Furthermore, we believe that beta-urogastrone, human EGF, might prove to be an effective drug in the clinical treatment of gastric ulcers.

Animals↗