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Biomedical subjects

M Okamoto

Publications and source records attributed to M Okamoto.

At least 451 records · Page 25Linked to original sources
PubMed1996

Antibody responses against Echinococcus multilocularis antigens in naturally infected Rattus norvegicus.

Two Norway rats, Rattus norvegicus, were found to be naturally infected with Echinococcus multilocularis in Japan. One of them was simultaneously infected with at least three different sized metacestodes of Taenia taeniaeformis. These two R. norvegicus rats and another R. norvegicus naturally infected with T. taeniaeformis and Capillaria hepatica were examined to see if they showed any antibody responses against these two cestode parasites with the view to obtaining more information on the importance of rats as the intermediate host for E. multilocularis. These R. norvegicus showed very poor antibody responses against the two cestode species, although the Wistar rats, R. rattus, experimentally infected with a single smaller sized metacestode of T. taeniaeformis showed stronger responses not only against T. taeniaeformis but also against E. multilocularis. Therefore the three R. norvegicus naturally infected with E. multilocularis and/or T. taeniaeformis demonstrated virtually no immune response, at least against these cestodes.

Animals↗
PubMed1996

Cytochrome P450(11 beta): ectopic expression in oocyte and its physiological implication.

Cytochrome P450(11 beta) (steroid 11 beta-hydroxylase) catalyzes an essential step for biosynthesis of glucocorticoid as well as mineralocorticoid, and therefore is believed to exist specifically in the adrenocortical mitochondria. We previously isolated a complementary DNA clone encoding this enzyme from bullfrog (Rana catesbeiana) adrenal tissues and characterized the enzyme expressed in COS cells. To explore the tissue distribution of the enzyme we performed Northern blot analysis. Unexpectedly we found that a large amount of the mRNA exists in the ovary as well as the adrenal gland. It was present in oocytes, but not in follicular cells. The P450 protein was not found during early stages of oocyte development, and at the final stage of maturation the message appeared to be translated. Evidence was obtained that the stage-dependent translation of the mRNA was due to the regulated polyadenylation at its 3'-end. In oocytes of various organisms several maternal mRNAs are known to add poly(A) tails in the cytoplasm during the progesterone-induced maturation.

Adrenal Glands↗
PubMed1996

Properties of H(+)-ATPase from rat liver lysosomes as revealed by reconstitution into proteoliposomes.

The properties of H(+)-ATPase from rat liver lysosomes were analyzed by reconstituting proton pump activity from solubilized enzyme and Escherichia coli phospholipids in proteoliposomes devoid of anion-channels. The reconstitution procedure involved solubilization of the ATPase with n-octyl-beta-D-thioglucoside in the presence of asolectin, and incorporation of the solubilized enzyme into E. coli phospholipid liposomes by dilution, freeze-thawing, and sonication. Proton pump activity of reconstituted H(+)-ATPase as detected by the ATP-dependent quenching of acridine orange fluorescence indicated that ATP can be replaced with dATP and to a lesser extent with GTP, but not with any other nucleotide, that Mg2+ can be replaced with Mn2+, but not with Ca2+, Sr2+, or Ba2+, that Zn2+, Pd2+, Cd2+, and Hg2+ were inhibitory, and that the enzyme was sensitive to inhibitors of v-type H(+)-ATPase, including bafilomycin A1, N-ethylmaleimide, DCCD, DIDS, and tri-n-butyltin. The enzyme showed unique sensitivity to anions and was activated by chloride, fluoride, and bromide from inside, but not from outside the vesicles. It was inhibited by sulfate, sulfite, and thiocyanate from outside the vesicles, and by nitrate from both inside and outside the vesicles.

Animals↗
PubMed1996

Enhanced engraftment of HTLV-I-infected human T cells in severe combined immunodeficiency mice by anti-asialo GM-1 antibody treatment.

The effects of anti-asialo GM-1 antibody (AAGM) treatment on the engraftment of human T-cell leukemia virus type I (HTLV-I)-infected human T cells in severe combined immunodeficiency (SCID) mice were studied. The frequency of tumor formation in an HTLV-I-transformed human T-cell line, MT-2 cells, at the site of inoculation was significantly higher in AAGM-treated than untreated mice (P<0.05): 16/18 (89%) and 16/26 (62%), respectively. The promotive effect of AAGM treatment on tumor development was marked in the early stage (less than 3 weeks), suggesting that the immediate reaction of natural killers to the inoculated cells may be important for the prevention of tumor development. The surface phenotypes and clonality of the tumor cells were the same as the MT-2 cells inoculated. Inoculation of peripheral blood mononuclear cells (PBMC) from one of the 4 adult T-cell leukemia/lymphoma (ATL) patients resulted in the development of tumors in AAGM-treated SCID mice. However, the surface phenotypes of the cells from these tumors were a mixture of B cells and T cells, suggesting that these tumors consisted of Epstein-Barr virus-transformed B cells and HTLV-I-transformed T cells. In addition, HTLV-I was detected by polymerase chain reaction in various organs of the mice inoculated with PBMC from the ATL patient and the asymptomatic carrier examined. These results suggest that elimination of natural killer function by AAGM treatment is important, although such treatment is not always necessary for the engraftment of HTLV-I-infected cells in SCID mice.

Animals↗
PubMed1996

Inferior vena cava filter used for unresectable renal cell carcinoma with tumor thrombi.

A titanium Greenfield inferior vena cava filter was used for the treatment of 2 patients with unresectable renal cell carcinomas with tumor thrombi to prevent a fatal pulmonary embolism induced by tumor clots released during systemic interferon therapy and embolization of the primary tumor. After treatment, the size of the renal cell carcinomas at the primary site and the tumor thrombi decreased by 50%. There were no fatal pulmonary embolisms or complications related to the filter during the observation period (24 and 25 months) after therapy. This method may be useful in the prevention of a fatal pulmonary embolism induced by embolization and systemic interferon therapy in these patients.

Aged↗
PubMed1996

Extracorporeal shock wave lithotripsy in von Willebrand's disease.

A renal calculus in a patient with von Willebrand's disease was successfully fragmented by extracorporeal shock wave lithotripsy (ESWL) with the administration of Haemate P. No serious bleeding was observed after ESWL. With supplementation of the missing von Willebrand's factor, ESWL may be applied to patients with this bleeding diathesis.

Adult↗
PubMed1996

Localization of the human IL-2-inducible T-cell kinase gene (ITK) to chromosome band 5q34 and the mouse gene (Itk) to chromosome 15 by fluorescence in situ hybridization.

ITK, predominantly expressed on T cells and myeloid cells, is a member of the Tec nonreceptor tyrosine kinase family. Both human ITK and mouse Itk genomic clones were isolated to assign the chromosome location. The human ITK gene was mapped to chromosome band 5q34 and the mouse gene to chromosome 15 by fluorescence in situ hybridization.

Animals↗
PubMed1996

Aerodynamic characteristics of the wings and body of a dragonfly

The aerodynamic characteristics of the wings and body of a dragonfly and of artificial wing models were studied by conducting two types of wind-tunnel tests and a number of free-flight tests of gliders made using dragonfly wings. The results were consistent between these different tests. The effects of camber, thickness, sharpness of the leading edge and surface roughness on the aerodynamic characteristics of the wings were characterized in the flow field with Reynolds numbers (Re) as low as 103 to 104.

Journal Article↗
PubMed1996

Pharmacokinetics of glycyrrhizin in rats with D-galactosamine-induced hepatic disease.

The pharmacokinetic behavior of glycyrrhizin (GZ) was examined in D-galactosamine-intoxicated (GAL) rats. When GZ was administered intravenously, the apparent volume of distribution (Vdss) and the total body clearance (CLtotal) were more significantly decreased in GAL rats than those in normal rats. When GZ was administered orally, the area under the plasma concentration-time curve (AUC), the mean residence time (MRT) and the time to reach the maximum plasma concentration (Tmax) for GZ were higher, but the maximum plasma concentration (Cpmax) in GAL rats was lower than that in normal rats. The bioavailability of GZ, however, was not significantly changed. On the other hand, the AUC for glycyrrhetic acid (GA), a main metabolite of GZ, after oral administration of GZ was higher in GAL rats than in normal rats, although there was no significant difference in MRT or Tmax, Cpmax or the bioavailability for GA between GAL and normal rats. The reasons for these differences in GAL rats would be changes in the absorption rate (reduced gastric emptying rate) and reduction of the hepatic elimination rates (biliary excretion of GZ and hepatic metabolism of GA).

Administration, Oral↗
PubMed1996

Prolongation of the life span of cardiomyopathic hamster by the adrenergic beta 1-selective partial agonist denopamine.

Influence of cardiotonic agents on the prognosis of heart failure depends on the individual therapeutic agents, and favorable and unfavorable effects of these agents have been reported in clinical trials. We studied the effect of the cardiotonic agent denopamine on the life span of cardiomyopathic hamsters (BIO 14.6 strain) in the heart failure period. Non-treated hamsters started to die at 40 weeks of age, and their survival rate decreased to 23.8% at the age of 65 weeks. Hamsters treated with denopamine (400 ppm in diet) from 36 weeks of age did not die until the age of 52 weeks, except in cases of accidental death. The survival rate of this group at 65 weeks of age was about 40%. Survival rates of these 2 groups were significantly different (P < 0.05) when animals with accidental death were excluded. To elucidate the mechanism of the effect of denopamine, we performed several experiments after dietary treatment with denopamine for 4 to 6 weeks from 37 weeks of age. Denopamine treatment lowered plasma levels of noradrenaline and dopamine (P < 0.05), but affected neither the cardiac contractility nor the beta-adrenoceptor density. In summary, denopamine significantly decreases the mortality of cardiomyopathic hamsters. Its effect to lower the plasma catecholamine levels may be responsible for the beneficial effect of denopamine.

Adrenergic beta-1 Receptor Agonists↗
PubMed1996

Embolization for ruptured superior mesenteric artery aneurysms.

Superior mesenteric artery (SMA) aneurysms are very uncommon. They are difficult to detect until they rupture and cause hypovolaemic shock. We performed embolization in four cases of aneurysm of branches of the superior mesenteric artery, succeeding in three cases without the need for surgical treatment. In the first case, the aneurysm was excised because of migration of a microcoil into the left hepatic artery. It was not retrieved because sufficient blood flow to the liver was shown on angiography after migration and no ischaemic change of liver was detected on laparotomy. In the second case, the aneurysm arose from the anterior pancreaticoduodenal artery. In the third case, the patient had two SMA aneurysms; one had been resected at surgery, another was revealed on follow-up angiography and embolized with microcoils. The fourth patient had a jejunal artery aneurysm with extravasation; haemostasis was achieved by packing it. In all four cases, no major complications were observed in the clinical course after embolization. Microcoils were considered to be the desirable embolic material, in order to prevent post-therapeutic ischaemic change. Embolization should be the treatment of choice for SMA aneurysms, because it is less invasive and takes less time than surgical treatment.

Adult↗
PubMed1996

Radiofrequency catheter ablation for a patient with Wolf-Parkinson-White syndrome associated with sustained atrial tachycardia.

Successful catheter ablation for a patient with both Wolff-Parkinson-White syndrome and sustained atrial tachycardia has not been reported. We describe a patient with Wolff-Parkinson-White syndrome associated with sustained atrial tachycardia, in whom an atrioventricular accessory pathway and an intra-atrial reentrant circuit were successfully ablated in a single session. Radiofrequency catheter ablation for the left-sided atrioventricular accessory pathway was performed via the trans-septal approach. Catheter ablation for the atrial tachycardia was achieved in the right atrium where the earliest and fractionated atrial activation was obtained. Catheter ablation for multiple lesions during a single session is feasible.

Catheter Ablation↗
PubMed1996

Response of conductance and resistance vessels of the coronary artery to intracoronary isosorbide dinitrate in patients with variant angina.

To elucidate the response of conductance and resistance vessels of the coronary artery after intracoronary isosorbide dinitrate (ISDN), we evaluated 11 patients with variant angina and 13 controls with a Doppler guidewire. Epicardial arterial diameter increased significantly after ISDN in patients with variant angina while it did not change significantly in the controls. Coronary diastolic flow velocity increased significantly in controls (p < 0.05), but was unchanged in patients with vasospastic angina. Coronary flow volume increased from 23.8 +/- 18.6 to 46.5 +/- 28.4 ml/min in patients with vasospastic angina as well as in the controls from 32.2 +/- 24.2 to 54.7 +/- 44.4 ml/min. Coronary resistance did not differ between the two groups before or after the injection of ISDN. Conductance vessels were dilated to a greater extent in the patients with variant angina. However, the response of resistance vessels did not differ significantly between the two groups.

Aged↗
PubMed1996

Multiple endocrine neoplasia type 1 associated with malignant lymphoma and other complications.

A 49-year-old female with multiple endocrine neoplasia (MEN) type 1 associated with malignant lymphoma, lipoma, functioning adenomatous goiter, non-functioning adrenal tumor, polyneuropathy, postoperative primary hyperparathyroidism, and hepatitis B virus was a human T lymphotropic virus type 1 (HTLV-1) carrier. She underwent parathyroidectomy for primary hyperparathyroidism at age 44. At age 49, examinations of the enlarged para-aortic lymph nodes revealed diffuse small non-cleaved B cell lymphoma in stage II, and other various complications were also found. Multiple tumorigenetic factors were considered to be involved in the present case.

Adrenal Gland Neoplasms↗
PubMed1996

[Demonstration and characterization of CD 46, membrane cofactor protein, in gastric cancer tissue].

CD 46, membrane cofactor protein, is a membrane protein which shows different expression and phenotypes with the organ or cell in the same individual. Previously, we reported that gastric CD 46 was expressed strongly in the mucosal epithelium, mucosa and endothelial cells of vessels in the submucosal layer. Western blot analysis revealed that gastric CD 46 was expressed as one broad band with a molecular weight ranging from 60 kDa to 69 kDa, which was different from that of lymphocytes. In this study, we investigated the differences in expression and characterization of CD 46 in gastric cancer obtained by surgery as compared with non-cancerous mucosa. Expression of CD 46 was greater in gastric cancer than in non-cancerous mucosa. In some cases, the phenotypes of CD 46 in gastric cancer were different from those in the non-cancerous tissue.

Aged↗
PubMed1996

[Expression and characterization of CD46, membrane cofactor protein, in human colonic mucosa].

CD 46, membrane cofactor protein (MCP), is a membrane regulatory glycoprotein of the complement system, and acts as a cofactor of factor I, which inactivates C3b and C4b bound on autologous cell membrane. MCP is present on human peripheral blood cells except erythrocytes, fibroblasts, epithelial and endothelial cells, and has been proved to exist in other organs including gastrointestinal tract recently. In this study the expression and characterization of MCP on normal human colonic mucosa was investigated. Immunohistochemical study showed MCP in the colonic mucosal epithelium. Western blot analysis revealed that MCP protein was expressed as a broad band of 50-65 kDa in all cases and another faint band of 43-46 kDa in 3 out of 20 cases, though the latter band was highly suspected to be originated from contaminated mononuclear cells in the colon.

Antigens, CD↗
PubMed1996

[Demonstration and characterization of CD46, membrane cofactor protein in the stomach].

CD46, membrane cofactor protein, is a glycoprotein widely present on the cell membranes and is different in molecular weight among organs or cells in the same individual. It acts as a cofactor of I of the complement system, which inactivates C3b bound to the autologous cells, and protects them from the attack of the complement. In this study CD46 was demonstrated in the stomach immunochemically. Gastric CD46 was expressed strongly in the mucosal epithelium, mucosa and endothelial cells of the vessels in the submucosal layer, whereas expressed weakly in the submucosa and muscle. Western blot analyses revealed that gastric CD46 was expressed as one broad band with molecular weight ranging from 60 kDa to 69 kDa, which was distinct from that of lymphocytes in the peripheral blood.

Aged↗