Search PubMed⌕ Search

Biomedical subjects

T Asano

Publications and source records attributed to T Asano.

At least 595 records · Page 33Linked to original sources
PubMed1991

[Can fluorodeoxyglucose-positron emission tomography evaluate the functional differentiation of hepatocellular carcinoma].

Tumor uptake of 18F-fluorodeoxyglucose (FDG) was studied by dynamic positron emission tomography (PET) in 23 cases of hepatocellular carcinoma. The metabolic rate constants, K1 to K4, were generated by non-linear least square fitting method. We confirmed that K3 from the PET study significantly correlated with directly measured hexokinase activity of the cancer tissue. The region of HCC always had higher K3 values, which represents the hexokinase activity compared with the non-cancerous region. By FDG images, however, in 50% of cases the cancer region could not be clearly defined from the surrounding noncancerous hepatic tissue. These HCC cases without accumulation of FDG had a high ratio of K4/K3 (K4 represents glucose-6-phosphatase activity), which correlated well with the inverse ratio of FDG accumulating images on PET. According to the PET images which is represented by K4/K3 and the hexokinase activity which is represented by K3, we divided these 23 cases into three groups and retrospectively compared their survival rates. The groups with high K4/K3 (greater than or equal to 0.40) had longer survival than other groups. From the view point of glucose metabolism, the value of K4/K3 calculated from dynamic studies of FDG-PET may represent the functional differentiation of HCC.

Carcinoma, Hepatocellular↗
PubMed1991

[Distribution of glycoconjugates in gerbil hippocampal neurons--histochemical study with lectins].

Paraffin-embedded sections of gerbil hippocampus were made and stained by use of lectins with different sugar specificities: Concanavalin A (Con A), wheat germ agglutinin (WGA), Ricinus communis agglutinin (RCA), Phaseolus vulgaris agglutinin (PHA-E), peanut agglutinin (PNA), soybean agglutinin (SBA), and Vicia villosa agglutinin (VVA) to investigate the distribution of glycoconjugates in this brain region. Nuclear membranes of all the neurons in the hippocampus were positively stained with Con A and PHA-E, whereas WGA revealed definite staining of cell membranes. Endothelial cells of blood vessels were intensely positive to RCA, suggesting its usefulness as a marker of endothelial cells. With SBA and VVA, a few neurons in Ammon's horn were positively stained, while no positive cells were observed in the dentate gyrus. CA2 and the medial part of the CA1 were also positive bilaterally with SBA and VVA. Some neurons in Ammon's horn and dentate gyrus were selectively stained on the surface of their cell bodies with PNA. The present results show that lectins used distinguish different subpopulations of hippocampal neurons, indicating a new possible classification of hippocampal neurons based on their differences in glycoconjugates.

Animals↗
PubMed1991

Posterolateral approach to the atlas and the axis.

We have developed a new surgical approach to the atlas and the axis including the odontoid process, in which the vertebral artery is transposed and an access to their lateral aspects without exposing the anterior structures of the neck is achieved. A case of successful excision of a bone tumor of the lateral mass of the atlas and a hypertrophic odontoid process by this approach is described.

Adolescent↗
PubMed1991

Two differential pathways from double-negative to double-positive thymocytes.

Murine thymocytes are divided into four major populations on the basis of expression of CD4 and CD8 antigens. The bulk of evidence favours the view that CD4-CD8- cells can develop into CD4-CD8+ and CD4+CD8- cells via the CD4+CD8+ stage in the thymus. However, CD4-CD8+ and CD4+CD8- thymocyte subsets contain not only CD3+ mature cells but also CD3- immature cells, which seem to be intermediate cells between CD4-CD8- and CD4+CD8+ cells. Here we demonstrate mouse strain differences in the proportion of immature single-positive thymocyte subsets in thymus at the steady or developing state. In C3H mice, immature CD4+CD8- is dominant in proportion over CD4-CD8+ in foetal thymus and in donor-derived thymocytes at an early stage of bone marrow transplantation. On the other hand, immature CD4-CD8+ is dominant over CD4+CD8- during T-cell development in the case of B10.BR mice. An intermediate pattern was shown in the case of F1 mice. Both of these immature single-positive subsets gave rise to double-positive cells after 24 hr culture. These results suggest that there exist two distinct differential pathways; one is from CD4-CD8- cells to CD4+CD8+ cells via CD4-CD8+ cells, and another is via CD4+CD8- cells, and that an application of the 'CD8 pathway' or 'CD4 pathway' seems to be genetically destined by BM-derived cells but not by thymic stromal cells.

Animals↗
PubMed1991

[Heterogeneity of anticardiolipin antibody].

The antibody to cardiolipin(ACA) was tested in patients with systemic rheumatic disease. The frequency of IgG ACA was 46/100(46.0%) in systemic lupus erythematosus(SLE). In other rheumatic disease, this was less than 20%. Significant correlation between the presence of IgG ACA and thrombosis and/or thrombocytopenia was found in patients with SLE. Eight sera containing high titered IgG ACA from lupus patients were selected for further inhibition study. Inhibitors were consisted of cardiolipin(CL), phosphatidyl(p-)serine, p-inositol, p-glycerol, p-ethanolamine, p-choline, ds-DNA, ss-DNA, fresh platelets(PLT)and fresh red blood cells(RBC). All sera were markedly inhibited by negatively charged phospholipids. In 4 sera(group B), there was moderate inhibition by ss-DNA, ds-DNA, PLT and RBC. In another 4 sera(group A), mild but significant inhibition was obtained by PLT alone. The number of platelet in group A was less than that in group B. There were some differences in inhibitory activity, suggesting heterogeneity of antibody to CL. It may be possible to speculate that heterogeneity of IgG ACA cause various combination of clinical features such as thrombocytopenia and thrombosis.

Abortion, Spontaneous↗
PubMed1991

[The suction effusion fluid is useful as a sample for blood biochemistry].

We examined whether the suction effusion fluid could be used as a new sample for blood biochemistry. The fluid was obtained from the skin surface of female mongrel dogs by transcutaneous suction after removal of the horny substance. The appropriate intraluminal pressure for suction was 300 mmHg at which the effusion fluid flow rate was 0.6 microliter/min/cm2. The blood biochemistry examination revealed that the creatinine (Cr) and urea (BUN) concentrations in the suction effusion fluid were similar to those in plasma and that the protein and lipid concentrations were much smaller than those in plasma. The six-hour study showed that the effusion fluid could be obtained for hours at the same skin area and that the Cr and BUN concentrations were consistently close to those in plasma. In uremia models, the Cr and BUN concentration in the suction effusion fluid was similar to and had an extremely high correlation (r = 0.985 and 0.982 respectively) to that in plasma through out the range for clinical practice. The skin biopsy revealed that the regeneration of the horny substance had started at one week after the suction and complete recovery was seen at four weeks. The invasiveness of the suction seemed to be small. The suction effusion fluid is a reliable material for measurement of Cr and BUN in plasma and, as it contains much less proteins and lipids, will be a good sample for biosensors.

Animals↗
PubMed1991

[Hepatic protein synthesis rate as an index of hepatic functional reserve in human liver].

Hepatic protein synthesis rate (HPS) in human livers were measured to evaluate hepatic functional reserve. HPS of 34 patients who underwent operations were studied and were divided into 4 groups. Normal liver (n = 7), obstructive jaundice (n = 9), liver cirrhosis (n = 8) and other hepatic dysfunction (n = 10). HPS in normal liver was 6.9 +/- 3.0 nmol/mg wet wt./10 min. HPS in obstructive jaundice liver was 17.1 +/- 10.3, and HPS in liver cirrhosis was 47.5 +/- 17.8. There were significant differences among these three groups. HPS correlated well with cholinesterase (r = -0.6533, P less than 0.01) and ICGR15 (r = 0.7315, P less than 0.01). In 15 patients who received hepatectomy, relations between HPS and postoperative complication were studied. There were no complications in patients whose HPS were less than 20 nmol/mg wet wt./10 min. in major hepatic resection and in patient whose HPS were less than 40 in a segmentectomy. Even if HPS were elevated, the operations were safe in subsegmentectomy and partial hepatectomy. So HPS would be one of the good indices to evaluate hepatic functional reserve.

Biopsy, Needle↗
PubMed1990

Endothelin: a potential modulator of cerebral vasospasm.

1-(5-Isoquinolinesulfonyl)-homopiperazine, HA1077, is a calcium antagonist with anti-vasospastic properties. This compound blocks intracellular actions of calcium in a variety of experiments. In the present study, we examined the effects of HA1077 on the vascular actions of endothelin, an endothelium-derived vasoactive peptide, in dogs in vitro and in vivo. Intracisternal injections of endothelin (0.01 nmol) produced a significant vasospasm, as measured by angiography, similar to that seen in the canine hemorrhage model. Infusion of HA1077 led to a significant dilatation of the spastic basilar artery in endothelin-treated dogs. The rank order of in vitro contractile activity in canine cerebral arteries was a stable thromboxane A2 analog greater than endothelin greater than 5-hydroxytryptamine greater than prostaglandin F2 alpha greater than histamine greater than noradrenaline. HA1077 effectively antagonized the endothelin-induced contraction of canine basilar arterial strips in both calcium-containing and calcium-free medium. The present results indicate that HA1077 is an effective antagonist for endothelin in vitro and in vivo.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

Isolation of three types of Gi from bovine spleen.

We have previously reported the purification of two alpha subunits of G proteins, Gi2 and Gi3, from bovine spleen. However, it recently became clear that the preparation of Gi3 alpha contained a significant amount of Gi1 alpha by the immunoblot analysis using specific antibodies. In this study, we purified these G proteins as a trimer form from bovine spleen, and obtained following results. (1) Gi3 was separated from Gi1 using Mono Q column chromatography. Isoelectric focusing was employed to distinguish Gi3 from Gi1 in the column eluates. (2) Purified Gi2 and Gi3 retained much higher activities to bind GTP gamma S or to be ADP-ribosylated by pertussis toxin than the alpha subunits purified previously. (3) Using these spleen Gi2 and Gi3 and bovine brain Gi1, the parameter of GTP gamma S binding to the three types of Gi was compared. Three Gis showed different rates of GTP gamma S binding but showed the similar Kd values.

Animals↗
PubMed1990

Distinctive regulation of the functional linkage between the human cation-independent mannose 6-phosphate receptor and GTP-binding proteins by insulin-like growth factor II and mannose 6-phosphate.

The rat insulin-like growth factor II (IGF-II) receptor develops transmembrane signaling functions by directly coupling to a guanine nucleotide-binding protein (G protein) having a 40-kDa alpha subunit, Gi-2, whereas recent studies have indicated that the IGF-II receptor is a molecule identical to the cation-independent mannose 6-phosphate receptor (CI-MPR), a receptor implicated in lysosomal enzyme sorting. In this study, by using vesicles reconstituted with the clonal human CI-MPR and G proteins, we indicated that the CI-MPR could stimulate guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) binding and GTPase activities of Gi proteins in response to IGF-II. The stimulatory effect of IGF-II on Gi-2 depended on the reconstituted amount of the CI-MPR; it could not be found in vesicles reconstituted with Gi-2 alone; and it was also observed on Gi-1 reconstituted with the CI-MPR in phospholipid vesicles. Of interest, such stimulatory effect was not reproduced by Man-6-P in CI-MPR vesicles reconstituted with either G protein. Furthermore, the affinity for Man-6-P-mediated beta-glucuronidase binding to several kinds of native cell membranes was not reduced by 100 microM GTP gamma S. Instead, however, Man-6-P dose-dependently inhibited IGF-II-induced Gi-2 activation with an IC50 of 6 microM in vesicles reconstituted with the CI-MPR and Gi-2. The action of 100 nM IGF-II was completely abolished by 1 mM Man-6-P. Such an inhibitory effect of Man-6-P was reproduced by 4000 times lower concentrations of beta-glucuronidase or similar concentrations of fructose 1-phosphate, but not by mannose or glucose 6-phosphate. These results indicate that the human CI-MPR has two distinct signaling functions that positively or negatively regulate the activity of Gi-2 in response to the binding of IGF-II or Man-6-P.

Animals↗
PubMed1990

GABAB receptors couple to G proteins Go, Go* and Gi1 but not to Gi2.

We studied the selectivity of GABAB receptors for coupling to G proteins by testing the ability of various purified G proteins to increase GABA binding to N-ethylmaleimide (NEM)-treated membranes of bovine brain. The addition of Go, Go* or Gi1 to NEM-treated membranes increased GABA binding in a dose-dependent manner. However, the addition of Gi2 did not elicit a marked increase in GABA binding. When alpha subunits of G proteins were mixed with various brain beta gamma subunit complexes composed of different gamma subunits, and they were added to the NEM-treated membranes, Gi2 with any beta gamma subunits hardly increased GABA binding. On the other hand, Go with any beta gamma subunits caused a marked increase, though Go with a small gamma subunit was more effective than that with a large gamma subunit. These data suggest that the selective coupling of the G proteins to GABAB receptors is determined by the alpha subunit.

Animals↗
PubMed1990

Overexpression of glucose transporter modulates insulin biosynthesis in insulin producing cell line.

Glucose transporter (GT) has been suggested to be involved in the insulin biosynthesis. However, the functional relationship between GT and insulin biosynthesis is not well understood. In this report, we have generated rat pancreatic B cell lines (RINr) that stably overexpress a cDNA encoding the brain type GT. These cell lines showed 3- to 4-fold increase in insulin mRNA and protein. These results suggest that GT might have some relationship to the insulin biosynthesis in the pancreatic B cells.

Animals↗
PubMed1990

Physiological expression of neural marker proteins in the heart of young rats.

The alpha-subunit of a GTP-binding protein Go (Go alpha), is a new marker protein of neurons and neuroendocrine cells. In our previous report, this protein was shown to be also distributed in the cardiac muscle of young rats, although the cardiac muscle is traditionally thought to be a non-neuronal tissue. To evaluate this unusual finding, expression of other neural marker proteins in the heart was examined. Immunohistochemical studies using antibodies against gamma-enolase, neurofilament and Go alpha protein revealed localization of these neural markers only in neurons and neuroendocrine cells in adult rats. In young rats, however, these neural markers were localized not only in these cells but also in the cardiac muscle. An enzyme immunoassay study of enolase isozymes showed that the heart of young rats was rich in neuron-specific gamma-enolase rather than in muscle-specific beta-enolase, while the heart of adult rats was deprived of the former and rich in the latter. These results suggest that the heart of young rats should be understood as a neuroendocrine tissue as well as a muscular tissue.

Animals↗
PubMed1990

Separation of two beta gamma subunit complexes of brain GTP-binding proteins composed of distinct gamma subunits.

The gamma subunits of GTP-binding proteins are always associated with beta subunits under physiological conditions, and at least two gamma subunits exist in the brain. We report here that brain beta gamma subunit complexes composed of distinct gamma subunits can be separated by anion exchange chromatography under nondenaturing conditions. One beta gamma complex was composed of a 36-kDa beta subunit and a 6-kDa gamma subunit and the other was composed of 36/35-kDa beta subunits and 4.5-kDa gamma subunit. The 6-kDa gamma subunit was phosphorylated by protein kinase C but the 4.5-kDa gamma subunit was not.

Animals↗