Search PubMed⌕ Search

Biomedical subjects

Y Fujimoto

Publications and source records attributed to Y Fujimoto.

At least 343 records · Page 19Linked to original sources
PubMed1991

Insulin-like growth factor-II (IGF-II)/Mannose-6-phosphate receptors are increased in primary human thyroid neoplasms.

Insulin-like growth factor (IGF)-II receptors were demonstrated in normal and neoplastic tissues of human thyroid. Specific binding of [125I]IGF-II to thyroid membranes was dependent on the time and temperature of incubation, and a steady state was achieved after 22 h of incubation at 4 degrees C. The binding of [125I]IGF-II was dose-dependently displaced by unlabelled IGF-II with 50% inhibition at an IGF-II concentration of 6 ng/ml. IGF-I had a relative potency of 1% compared to IGF-II, and insulin showed no inhibition at concentrations as high as 2000 ng/ml. Scatchard analysis of the binding data revealed a single class of IGF-II receptor with high affinity. Affinity crosslinking and autoradiography demonstrated the type II IGF receptors. Specific binding of [125I]IGF-II to thyroid papillary cancer tissues (mean [S.D.]13.2[1.3]% per 200 micrograms protein, n = 8) was significantly (P less than 0.01) higher than that to the surrounding normal tissues (4.8 [0.5]%). The binding in follicular cancer and follicular adenoma was also significantly higher than that in the corresponding normal tissues. The higher IGF-II binding to neoplastic tissues was due to an increase in the number of binding sites without any change of affinity. These results suggest that the increased IGF-II receptors may be involved in growth or functions of thyroid neoplasms.

Binding, Competitive↗
PubMed1991

Purification and characterization of leucine-specific aminopeptidase from the soluble fraction of human placenta.

A soluble aminopeptidase distinct from two enzymes described previously was isolated from human placenta and some of its properties were investigated. The three aminopeptidases were separated by DEAE-cellulose chromatography. The newly found aminopeptidase exhibits specific hydrolysis of leucine derivatives among various synthetic substrates. However, a broad substrate specificity was observed toward some natural bioactive peptides.

Amino Acid Sequence↗
PubMed1991

Triacylglycerol lipase mediated release of arachidonic acid for prostaglandin synthesis in rabbit kidney medulla microsomes.

The effect of triarachidonin on the synthesis of prostaglandins in rabbit kidney medulla microsomes was examined. Medulla microsomes were incubated with triarachidonin in 0.1 M--Tris/HCl buffer (pH 7.0) containing reduced glutathione and hydroquinone and the formed prostaglandin E2, prostaglandin F2 alpha and prostaglandin D2 were measured by high-pressure liquid chromatography using 9-anthryldiazomethane for derivatization. The addition of triarachidonin (1-10 microM) stimulated prostaglandin formation in a dose-dependent manner. Under our incubation conditions rabbit kidney medulla was found to produce prostaglandin E2 mainly. When arachidonic acid, instead of triarachidonin, was added to the incubation mixture of microsomes, the identical profile of prostaglandin products was obtained. When the pH of the reaction mixture was changed from 7.0 to 8.0, the rate of triarachidonin-induced prostaglandin E2 formation was approximately 60% of that observed at pH 7.0. Studies utilizing Ca2+ and EGTA revealed that triacylglycerol lipase of kidney medulla is independent of Ca2+. The addition of epinephrine made the stimulatory effect of triarachidonin on prostaglandin E2 formation more pronounced. These results suggest that epinephrine-activated triacylglycerol lipase is present in the renomedullary microsomes, and this enzyme activity is a potential mediator of release of arachidonic acid for prostaglandin synthesis in the kidney medulla.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1991

C cell hyperplasia and carcinoma developing in sheep with experimentally-induced lymphosarcoma.

Two cases of C cell hyperplasia and one case of C cell carcinoma of the thyroid glands were bilaterally recognized in 11 sheep with experimentally-induced lymphosarcoma. The serum calcium concentration in the C cell carcinoma case was slightly increased above the normal concentration of around 9 mg per dl. Bilateral C cell hyperplasia also developed in the thyroid lobes of the C cell carcinoma case. Immunohistochemically, hyperplastic C cells and tumour cells were positive for calcitonin, calcitonin gene-related peptide, chromogranin A and neurone-specific enolase. No amyloid deposition nor multiple endocrine neoplasia was demonstrated in any of the cases. Ultrastructurally, many secretory granules were observed in the cytoplasm of neoplastic cells constituting the C cell carcinoma and in the hyperplastic C cells.

Animals↗
PubMed1991

Adrenocorticotropic hormone-independent bilateral adrenocortical macronodular hyperplasia as a distinct subtype of Cushing's syndrome. Enzyme histochemical and ultrastructural study of four cases with a review of the literature.

Four patients with adrenocorticotropic hormone (ACTH)-independent bilateral adrenocortical macronodular hyperplasia (AIMAH) were examined. All of them were men whose ages ranged from 37 to 52 years. Plasma cortisol levels were high, with a loss of diurnal rhythmicity, and plasma ACTH was undetectable. Adrenal cortisol secretion was not suppressed by dexamethasone, but it was ACTH responsive. Test results for corticotropin-releasing hormone (CRH) also were negative. Image analyses revealed a normal sella turcica and significantly enlarged adrenal glands, which showed enhanced uptake of isotope. Both adrenal glands in all cases were between 72 and 176 g in combined weight and were composed of, and distorted by, yellow nodules. Histologically, small cortical cells with or without lipid, occasional clear cells, and rare compact cells of the usual size were increased in number in the glandular cords. Enzyme histochemically, cortical cells showed weaker activity for 3 beta hydroxysteroid dehydrogenase and other enzymes than did usual cortisol-producing adenomas. Ultrastructurally, they had moderately to poorly developed smooth endoplasmic reticulum. Nonnodular areas of the cortex consisting of nonproliferating cells were atrophic and contained no compact cell zone. This is similar to the adrenal cortices attached to cortisol-producing adenomas. These features are unique to AIMAH and suggest the presence of a distinct subtype of Cushing's syndrome.

Adrenal Cortex↗
PubMed1991

Detection of arginine esterase activity in human follicular fluid.

One major fraction hydrolysing arginine ester and amido derivative (major preparation) was detected and separated from human follicular fluid by Cellulofine GCL-2000 gel filtration. The best ester and amide substrates for this preparation were acetyl-glycyl-lysine methyl ester (Ac-Gly-Lys-Me) and D-valyl-L-leucyl-L-arginine-p-nitroanilide (Val-Leu-Arg-pNA), respectively. The preparation contained plasmin and plasminogen; lysine-Cellulofine adsorption and elution changed the substrate specificity of its esterolytic activity. After treatment by lysine-Cellulofine adsorption and elution, the basic and acidic arginine esterase activities of the major preparation were separated by CM- and DEAE-cellulose adsorption and elution, respectively. The substrate specificity of these two esterolytic enzyme activities differed before and after adsorption of the major preparation to the lysine affinity column.

Amino Acid Sequence↗
PubMed1991

Malignant T-cell lymphoma of the pancreas.

A case of malignant T-cell lymphoma of the pancreas is presented. Previously reported histological data confirming this disease are reviewed to elucidate features that may suggest this disease and how to differentiate between T- and B-cell lymphoma of the pancreas.

Adult↗
PubMed1991

Cytotoxic acetylenes from Panax quinquefolium.

Three new cytotoxic polyacetylenes, PQ-1 (1), PQ-2 (2) and PQ-3 (3), have been isolated from Panax quinquefolium. The structures of these acetylenes were determined by analyses of their 1H-1H and 1H-13C COSY spectra. All these compounds exhibited strong cytotoxic activities against leukemia cells (L 1210) in tissue culture.

Acetylene↗
PubMed1991

Treatment of torsade de pointes with intravenous magnesium in idiopathic long QT syndrome.

A middle aged woman with idiopathic long QT syndrome was found to have repetitive ventricular tachycardia of the "torsade de pointes" type. The arrhythmia was resistant to mexiletine and lidocaine, but was controlled by intravenous magnesium sulfate (MgSO4). The recurrent attacks were abolished by a bolus of 2.0 g MgSO4, and extremely prolonged QTU interval was reduced by intravenous infusion of 5 mg/min MgSO4 for 36 h. This case shows the effectiveness of intravenous magnesium in controlling the attack of torsade de pointes in patients with idiopathic long QT syndrome.

Adult↗
PubMed1991

Clinical study on coupling interval of ventricular premature contraction in patients with organic heart disease.

The characteristics of the coupling interval (CI) of ventricular premature contraction (VPC) were studied in 100 patients with frequent VPCs using 24 h ambulatory ECG recording. All R-R intervals were registered on computer to determine the mean value of CIs (Mean CI) and the standard deviation of CIs (SD-CI). We compared the Mean CI and the SD-CI between idiopathic VPCs and VPCs with organic heart disease (OHD). In addition, we evaluated the efficacy of disopyramide (DP) and mexiletine (MX) and we examined the relationship between the efficacy of these drugs and the characteristics of CI. The Mean CI of VPCs with OHD was longer than that of idiopathic VPCs (530 vs. 494 msec, p less than 0.05). The SD-CI of VPCs with OHD was larger than that of idiopathic VPCs (54.1 vs. 39.3 msec, p less than 0.01). In all treated cases, the drug efficacy was not different between DP (11/18, 61%) and MX (9/19, 47%). However when we isolated cases of OHD, we found a tendency that DP (9/12, 75%) was more effective than MX (7/16, 44%). In cases where DP was administered, the Mean CI of VPCs was not different between effective and ineffective cases, while in cases where MX was administered, the Mean CI of ineffective cases had a tendency to be longer than that of effective cases (552 vs. 506 msec, p less than 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Complexes, Premature↗
PubMed1991

Stimulation of prostaglandin synthesis in rabbit gastric antral mucosal slices by desferrioxamine in vitro.

Desferrioxamine is an iron-chelating agent used in the treatment of iron overload. It is a powerful inhibitor of iron-dependent radical reactions. The effect of desferrioxamine of prostaglandin (PG) synthesis and metabolism in rabbit gastric antral mucosal slices has been examined. Desferrioxamine significantly enhanced the production of PGE2 and PGF2 alpha. The formation of 13,14-dihydro-15-keto PGE2 and 13,14-dihydro-15-keto PGF2 alpha was also increased slightly by desferrioxamine. The addition of Fe3+ or Al3+ blocked the stimulatory action of desferrioxamine on PGE2 and PGF2 alpha production. Desferrioxamine appears to be stimulating the activity of PG cyclooxygenase through the removal of endogenous antral mucosal iron. These results suggest that desferrioxamine has the potential to increase the PG levels in gastric mucosa by primarily stimulating PG biosynthesis. The possibility that desferrioxamine may be of therapeutic value in the treatment of ischemic injury in the stomach is discussed.

Aluminum↗
PubMed1991

A new latent arginine esteropeptidase from human submaxillary gland.

One of the arginine esteropeptidases in human submaxillary gland was purified from microsomal membranes. The enzyme is inactive in membranes and requires trypsin treatment for its full activation. The trypsin-activated enzyme was purified to homogeneity. Its molecular weight was determined to be 94,000 by SDS-polyacrylamide gel electrophoresis. Among various substrates examined, the obtained enzyme exhibited high specific activities toward Tos-Arg-OMe (esterolysis) and D-Ile-Pro-Arg-pNA (amidolysis). The enzyme was inhibited by some serine proteinase inhibitors, whereas inhibitors of other types of proteinases did not affect or only scarcely affected it. The enzyme appears to be distinct from other arginine esteropeptidases previously described.

Amides↗
PubMed1991

Effects of Fe2+, Fe3+ and desferrioxamine on paraquat accumulation by rabbit kidney cortex slices.

Effects of Fe2+, Fe3+ and desferrioxamine (DFO) on the accumulation of paraquat (PQ) into rabbit kidney cortical slices were studied. Fe3+ showed dose-dependent inhibition of PQ accumulation. Fe2+ had a more powerful stimulatory effect on the lipid peroxidation of cortical slices than Fe3+, but it did not reduce PQ accumulation. The addition of DFO made the inhibitory effect of Fe3+ on PQ accumulation more pronounced. These results suggest that Fe3+ is able to inhibit the accumulation of PQ independent of its peroxidative action, and that Fe(3+)-desferrioxamine (ferrioxamine) may serve as an antidote for the toxicity of PQ.

Animals↗
PubMed1990

Diffuse sclerosing variant of papillary carcinoma of the thyroid. Clinical importance, surgical treatment, and follow-up study.

A diffuse sclerosing variant is not very rare among papillary carcinomas of the thyroid when the patients are female and younger than 30 years of age. The variant is characterized by diffuse involvement of one or both thyroid lobes, with dense sclerosis, patchy lymphocytic infiltration, and abundant psammoma bodies. Controversy still exists concerning its prognosis. We reviewed our experience with 14 patients treated between 1958 and 1988. All patients were young females, their age being from 10 to 28 years with a mean of 19.6. Hashimoto's thyroiditis had been suspected in nine patients before they came to our clinic. Nowadays the diagnosis of this cancer is possible when we have this entity in mind and detect abundant psammoma bodies either by ultrasonography or by soft-tissue roentgenography of the neck. Total thyroidectomy with modified neck dissection was carried out in eight patients, subtotal thyroidectomy with neck dissection in five, and lobectomy with neck dissection in one. All of them are alive and well without distant metastasis at a mean follow-up of 16 years. Because most of the patients with this variant of papillary carcinoma are young women and the prognosis is favorable, a complete resection without causing later recurrence, but also cosmetic and complication-free surgery, should be considered.

Adolescent↗