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Biomedical subjects

Y Ishikawa

Publications and source records attributed to Y Ishikawa.

At least 19 recordsLinked to original sources
PubMed1992

Lung cancers associated with thorotrast exposure: high incidence of small-cell carcinoma and implications for estimation of radon risk.

The widely accepted concept that the alpha-emitting radionuclide radon (222Rn, 220Rn) induces lung cancers in humans has been based on the excess of lung tumours observed in underground miners extracting uranium or other substances. However, this poses the important question of whether radon is the only carcinogenic factor because such miners are also heavily exposed to mine dusts including silicates, diesel exhaust, etc. in their working environment. Patients to whom Thorotrast was administered continuously exhale radon (220Rn) derived from 232Th deposits in the body and therefore provide a good model for lung carcinogenesis by radon without concomitant dust exposure. We therefore investigated lung-cancer incidence in our epidemiological follow-up series, analysing the histological types of 11 lung cancers which were found among 359 Thorotrast autopsy cases and measuring radioactivity in the breath of living Thorotrast patients. The study revealed that, while the proportion of small-cell lung cancers considered to be related to alpha-particles was significantly increased, the overall lung cancer incidence was not significantly higher than in controls, in spite of the high level of 220Rn in the patients' breath. This result suggests that radon in the lung does induce cancers (particularly small-cell carcinomas) but that the induction rate is not as high as expected from risk factors associated with mining. Thus, excess lung cancers among the miners might be related to the combined effects of exposure to radon and mine dusts, and not solely to radon.

Aged↗
PubMed1992

Cloning and characterization of a sixth adenylyl cyclase isoform: types V and VI constitute a subgroup within the mammalian adenylyl cyclase family.

A sixth member of the mammalian adenylyl cyclase family has been isolated from a canine cardiac cDNA library. This isoform is more highly homologous to type V than to the other adenylyl cyclase types; sequence similarity is apparent even in the transmembrane regions where the greatest divergence among the types exists. Type VI mRNA expression is most abundant in heart and brain; however, unlike type V, a low level of expression is also observed in a variety of other tissues examined. Type VI adenylyl cyclase can be stimulated by NaF, guanosine 5'-[gamma-thio]triphosphate, and forskolin but not by Ca2+/calmodulin, whereas it is inhibited by adenosine and its analogues. Comparison of both their structural and biochemical properties suggests that types V and VI constitute a distinct subgroup of the mammalian adenylyl cyclase family.

Adenosine↗
PubMed1992

Cytogenetic characteristics of childhood non-Hodgkin lymphoma.

Cytogenetic studies were performed successfully on 24 patients with non-Hodgkin lymphoma (NHL) who were younger than 15 years of age. Of these, 22 patients (92%) had abnormal clones. With respect to histologic findings, 3 (25%) of the 12 patients with lymphoblastic lymphoma had 14q11 translocations and 2 (17%) had t(9;17) (q34;q23). Four (80%) of the five patients with small non-cleaved cell lymphoma had t(8;14)(q24;q32). With respect to immunologic findings, four (44%) of the nine patients with T-cell lymphoma had abnormalities consisting of 14q11 and 7q36 translocations, in which the T-cell receptor genes resided. Three (33%) of the patients with T-cell lymphoma had t(9;17)(q34;q23). However, three (43%) of the seven patients with B-cell lymphoma had t(8;14) (q23;q32), and two (29%) of the patients with B-cell lymphoma had an extra i(11q) chromosome with a resultant 11q tetrasomy. Non-T-cell non-B-cell lymphomas, which occurred in 21% of all patients, showed various chromosomal abnormalities. This study demonstrated that, in childhood NHL, karyotype correlates closely with immunophenotype, clinical features, and histologic findings.

Adolescent↗
PubMed1992

Isolation and characterization of a novel cardiac adenylylcyclase cDNA.

A novel adenylylcyclase cDNA (type V) was isolated from a canine heart cDNA library. Northern blotting indicates that the expression of this message is most abundant in heart with a lesser amount in brain but is absent in a variety of other tissues including lung, kidney, skeletal muscle, lymphocyte, and testis. The putative protein product predicted from the cDNA sequence has the motif of tandem six-transmembrane spans separated by a large hydrophilic cytoplasmic loop as seen in other members of the adenylylcyclase family. When this protein is expressed using a CMT cell transient expression system, the adenylylcyclase activity was stimulated by NaF, GTP gamma S, and forskolin, but not by calmodulin. The activity was inhibited in a concentration-dependent manner with either P-site active agents such as adenosine or in the presence of calcium. These data indicate that the protein encoded by this cDNA is adenylylcyclase with the biochemical features characteristic of the cardiac isoform.

Adenosine↗
PubMed1992

Moderate oxidation of hypertriglyceridemic low-density lipoprotein causes apolipoprotein B epitope change and enhances its uptake by macrophages.

We prepared monoclonal antibody (MabB4) that selectively binds to acetylated low-density lipoprotein (LDL). Native hypertriglyceridemic LDL (HT-LDL) obtained from IIb and native normotriglyceridemic LDL (NT-LDL) from type IIa scarcely bound with MabB4. When these LDL were oxidized moderately by incubation with copper ions, the binding of MabB4 to HT-LDL was enhanced compared to that of NT-LDL, although the contents of the hydroperoxide they produced were the same. The incorporation of moderately oxidized HT-LDL into macrophages was enhanced compared to that of NT-LDL, and the rate of incorporation parallel the binding of LDL for MabB4. These results suggested that moderate oxidation of HT-LDL expressed some apolipoprotein B epitope on the surface of acetylated LDL to a much greater degree than NT-LDL, and that this expressed epitope might work as a ligand of moderately oxidized HT-LDL for the recognition by macrophages.

Apolipoproteins B↗
PubMed1992

Isolation of canine C-reactive protein and characterization of its properties.

C-reactive protein (CRP) was isolated from the acute phase serum of dogs subjected to surgical stimulation. Its properties were characterized. Canine CRP was isolated by ion-exchange chromatography using DEAE-Sephacel and DEAE-Sephadex A-50 and affinity chromatography using protein A-Sepharose CL 4B in combination with agar-block electrophoresis. In immunoelectrophoresis, canine CRP had the same gamma-mobility as human gamma-type CRP. The molecular weight of purifined canine CRP was estimated by gel filtration and sodium dodecyl sulfate polyacrylamide gel electrophoresis to be approximately 157,000 and 155,000 respectively. This CRP was a thermolabile protein which completely lost its antigenicity by heating at 70 degrees C for 15 min. The serum concentration of CRP in normal beagle dogs ranged from 0.198 to 0.826 micrograms ml-1 (0.486 +/- 0.170 micrograms ml-1). The concentration was acutely increased by surgery as it was in man and was rapidly decreased with convalescence. Dogs can be a useful animal model for investigation of the mechanism of CRP production and the function of CRP.

Acute-Phase Reaction↗
PubMed1992

Establishment of the primary structure of the major lipid-dependent Ca2+ binding proteins of chicken growth plate cartilage matrix vesicles: identity with anchorin CII (annexin V) and annexin II.

Electron microscopic studies of calcifying vertebrate tissues reveal the locus of de novo mineral formation within matrix vesicles (MV). The direct involvement of MV in the initiation of mineral formation is supported by the fact that MV isolated from avian growth plate cartilage rapidly accumulate large amounts of Ca2+ and P(i) and induce mineral formation. Exploration of the constituents of MV has revealed two major protein components, a 33 and a 36 kD protein, the former of which binds to cartilage-specific collagens. These annexin-like proteins bind to acidic phospholipids in the presence of submicromolar levels of Ca2+. Antibodies raised against both the purified 33 and the 36 kD MV annexin do not cross-react with the other, indicating that they are distinct proteins. Reported here are studies elucidating the primary structure of both MV proteins using both conventional protein and molecular biologic methods. These studies establish that the 33 kD protein is nearly identical to anchorin CII (annexin V) and that the 36 kD protein is identical to avian annexin II. Immunolocalization studies show that hypertrophic chondrocytes at the calcification front of avian growth plate contain the highest level of these annexins. Further, immunogold labeling indicates that the annexins are localized within MV isolated from the growth plate. Recent studies indicate that annexin V is a new type of ion-selective Ca2+ channel protein that possesses selective collagen binding properties. Since MV are tightly associated with the collagen- and proteoglycan-rich matrix, it is tempting to speculate that this MV protein may be a component of stretch-activated ion channels that enhance Ca2+ uptake during mechanical stress.

Amino Acid Sequence↗
PubMed1992

Modulation of cultured chicken growth plate chondrocytes by transforming growth factor-beta 1 and basic fibroblast growth factor.

Expression of several cellular and matrix proteins which increase significantly during the maturation of growth plate cartilage has been shown to be affected by various endocrine and autocrine factors. In the studies reported here, transforming growth factor-beta (TGF-beta 1) and basic fibroblast growth factor (bFGF) were administered to primary cultures of avian growth plate chondrocytes at pre- or post-confluent stages to study the interplay that occurs between these factors in modulating chondrocytic phenotype. Added continuously to pre-confluent chondrocytes, TGF-beta 1 stimulated the cells to produce abundant extracellular matrix and multilayered cell growth; cell morphology was altered to a more spherical configuration. These effects were generally mimicked by bFGF, but cell shape was not affected. Administered together with TGF-beta 1, bFGF caused additive stimulation of protein synthesis, and alkaline phosphatase (AP) activity was markedly, but transiently enhanced. During this pre-confluent stage, TGF-beta 1 also increased fibronectin secretion into the culture medium. Added to post-confluent cells, TGF-beta 1 alone caused a dosage-dependent suppression of AP activity, but bFGF alone did not. Under these conditions, TGF-beta 1 and bFGF had little effect on general protein synthesis, but TGF-beta 1 alone caused large, dosage-dependent increases in synthesis of fibronectin, and to some extent type II and X collagens. Given together with bFGF, TGF-beta 1 synergistically increased secretion of fibronectin. These findings reveal that regulation of phenotypic expression in maturing growth plate chondrocytes involves complex interactions between growth factors that are determined by timing, level, continuity, and length of exposure.

Alkaline Phosphatase↗
PubMed1992

A new method for determination of urinary citrate.

We have developed a new assay technique using high-performance liquid chromatography. The assay was performed at a flow rate of 0.7 ml/min, a temperature of 60 degrees C and an ultraviolet absorption of 214 nm. Comparison of the results of the new assay with the results obtained for identical samples using the conventional fluorometric method demonstrated a very high correlation coefficient of 0.931.

Adult↗
PubMed1992

Preparation of latex sensitized with rabbit IgG antibody for slide reversed passive agglutination.

A method is described for preparing latex particles sensitized with IgG antibody (IgG-sensitized latex) applicable to the slide reversed passive agglutination (RPLA) test. Soap-free latex (latex) was sensitized with IgG which had been isolated from rabbit anti-bovine lactoferrin serum using protein A Sepharose CL 4B. Unadsorbed protein-binding sites on the surface of latex were blocked with bovine serum albumin (BSA). IgG-sensitized latex that gave better agglutination in RPLA could be selectively obtained by centrifugation at 19 900g for 15 min in 0.01 mol/L glycine buffer (pH 7.3; specific gravity 1.042) containing 3% NaCl, 5% saccharose and 2% choline chloride. By dispersing this IgG-sensitized latex in 0.01 mol/L glycine buffer (pH 7.3) containing 1-2% BSA, a uniformly suspended, highly reactive, readily agglutinable preparation was obtained.

Adsorption↗
PubMed1992

Diurnal variation of amylase secretion is coupled with alterations of beta-adrenoceptors in the rat parotid gland.

Diurnal changes in the neurotransmitter receptors are important for studying the receptor function in neurophysiology. The purpose of this study is to gain an insight into the regulatory mechanisms of the diurnal variation of amylase secretion. Rat salivary amylase levels showed a diurnal variation with two peaks, a marked peak at 13 h and a lesser peak at 21 h. This increase in salivary amylase levels was completely inhibited by pretreatment of rats with the beta-adrenergic antagonist propranolol, but not by the alpha-adrenergic antagonist phentolamine. Amylase level in parotid tissue homogenate also showed a diurnal change, but there was only one peak, at 13 h. The number of maximal binding sites (Bmax) for [3H]dihydroalprenolol (DHA) in parotid membranes showed a diurnal variation with two marked peaks at 13 and 21 h, but the affinity of parotid beta-adrenoceptors for agonists or antagonists did not show any diurnal changes. Phosphorylation of nuclear non-histone proteins in the rat parotid gland showed diurnal variation with two marked peaks at 13 and 21 h. These results indicate that a diurnal variation in the number of rat parotid beta-adrenoceptors, which is presumably regulated by gene expression, is coupled with a change in salivary amylase secretion.

Amylases↗
PubMed1992

SPECT demonstration of splenosis.

Splenosis is defined as the heterotopic autotransplantation of splenic tissue. The main cause of splenosis is splenic rupture following abdominal trauma, in which fragments of splenic tissue are seeded throughout the peritoneal cavity. Demonstration of splenosis by scintigraphy or CT imaging has been reported, but there is no previous report of simultaneous demonstration by SPECT and CT imaging. Autotransplantation of splenic tissue in the abdominal cavity forms a solid tumor-like image on CT and is difficult to differentiate from other abdominal masses. In such cases, SPECT demonstration of splenosis is very important for identification of its exact site. A case report of splenosis is presented, in which simultaneous demonstration by SPECT and CT was performed. This was confirmed at laparotomy for gastrectomy.

Abdominal Neoplasms↗
PubMed1992

Association of N-glycosylation of apolipoprotein B-100 with plasma cholesterol levels in Watanabe heritable hyperlipidemic rabbits.

We have previously demonstrated the heterogeneity of N-linked sugar chains of apolipoprotein (apo) B-100 in Watanabe heritable hyperlipidemic (WHHL) rabbit and fasting Japanese White rabbits (Arteriosclerosis, 10 (1990) 386-393). To investigate further the role of N-linked sugar chains of apo B-100 in lipid metabolism, we examined the correlation between the N-glycosylation of apo B-100 and serum cholesterol levels in WHHL rabbits. The N-linked sugar chains of apo B-100 were liberated by hydrazinolysis, followed by NaB3H4 reduction and were fractionated by paper electrophoresis and BioGel P-4 column chromatography. These were found to consist of one neutral (N) and two acidic fractions (A1 and A2). N contained a high mannose type oligosaccharide consisting of Man5.GlcNAc2 to Man9.GlcNAc2, while A1 and A2 contained monosialylated and disialylated complex type oligosaccharides, respectively. The molar ratio varied among the 5 WHHL rabbits. There was an inverse correlation between the ratio of acidic oligosaccharide fractions (A1 + A2) and serum cholesterol levels (r = -0.971, P less than 0.01) in the 5 WHHL rabbits. These results indicate that the N-glycosylation of apo B-100 is closely related to cholesterol metabolism in WHHL rabbits.

Animals↗
PubMed1992

Phenotyping of lymphocyte subsets in the vascular and epithelial lesions of a cow with malignant catarrhal fever.

Surface marker analysis of lymphoid cells infiltrating the vascular and epithelial lesions of a cow with malignant catarrhal fever (MCF) was conducted by immunohistochemistry using ten monoclonal antibodies. The majority of lymphoid cells in these lesions had BoCD8, BoCD6 or BoCD2, but they rarely possessed N-cell (BoCD5+/BoCD4-/BoCD8-, non-T non-B) markers. Similar reactivity was seen in lymphoid cells of perivascular infiltrates in the liver, heart and brain, and in T-dependent areas of lymph nodes. These results suggest involvement of cytotoxic T-lymphocytes in the pathogenesis of MCF.

Animals↗
PubMed1992

Comparison of imaging methods for localization of parathyroid tumors.

Preoperative localization of parathyroid tumors by computed tomography (CT), thallium-201/technetium-99m pertechnetate subtraction scintigraphy (Tl-201/Tc-99m), ultrasonography (US), and magnetic resonance imaging (MRI) was compared in patients with hyperparathyroidism (HPT) to examine the characteristics of each method. A total of 87 patients with HPT were divided into two groups according to the time when they were examined. Patients in group I were examined before MRI had been introduced in our hospital, and a 2.5-MHz transducer probe was used for US. Those in group II were examined by MRI and US using a 7.5-MHz transducer probe. Group I included 45 patients (36 with primary hyperparathyroidism [PHPT] and 9 with secondary hyperparathyroidism [SHPT]), and group II included 42 patients (15 with PHPT and 27 with SHPT). In both PHPT and SHPT and SHPT of group I and PHPT of group II, there was no significant difference in detection rates between all diagnostic methods. In patients with SHPT in group II, the detection rate was significantly higher for CT than for Tl-201/Tc-99m and MRI (both p less than 0.01), and for US than for Tl-201/Tc-99m (p less than 0.01). In both groups I and II, the detection rate of each study method was significantly higher in patients with PHPT than in those with SHPT (all p less than 0.01). Compared with group I, the rate was significantly improved in group II, in both types of patients. Regarding the location of the parathyroid tumor, the detection rate of CT was significantly higher for upper parathyroid glands than for lower glands, whereas that of US and Tl-201/Tc-99m was significantly higher for lower glands. The detection rate sharply increased when the tumor weight reached 250 mg (CT, US) or 1,000 mg (Tl-201/Tc-99m, MRI).

Adult↗