Biomedical subjects

H Fukui

Publications and source records attributed to H Fukui.

At least 271 records · Page 15Linked to original sources

PubMed1993

High, stable expression of the bovine histamine H1-receptor coupled to [Ca2+]i mobilisation in CHO-K1 cells.

The bovine H1-receptor DNA was transfected into Chinese hamster ovary cells (CHO-K1) using an expression vector. Binding studies revealed very high expression levels of the receptor which was found to have a Kd for [3H]-mepyramine of 1 nM. Addition of histamine resulted in a concentration-dependent increase in intracellular calcium which was found to involve both release from intracellular stores and entry across the plasma membrane. Furthermore, the response demonstrated the pharmacological characteristics of an H1-receptor-mediated event. Thus, we present the first report of the high, functional expression of the bovine H1-receptor coupled to mobilisation of intracellular calcium in CHO-K1 cells.

Animals↗

PubMed1993

Soluble forms of the interleukin-6 signal-transducing receptor component gp130 in human serum possessing a potential to inhibit signals through membrane-anchored gp130.

The interleukin-6 (IL-6) signal is transduced through membrane-anchored gp130, which is associated with IL-6 receptor (IL-6R) in the presence of IL-6. Soluble forms of gp130 (sgp130) with molecular weights of 90 and 110 Kd were found in human serum. In the presence of recombinant IL-6 (rIL-6), serum sgp130 were capable of associating with serum sIL-6R. By the sandwich enzyme-linked immunosorbent assay, healthy human sera was shown to contain 390 +/- 72 ng/mL of sgp130. A mouse pro-B-cell line-derived transfectant, BAF-130, expressing human gp130 was used to examine the function of serum sgp130. When supplemented with rIL-6, human serum induced DNA synthesis in BAF-130 cells, whereas the serum deprived of sIL-6R did not. In contrast, the DNA synthesis induced in BAF-130 cells by rIL-6-supplemented serum was increased when the serum was deprived of sgp130. These results indicated that serum sgp130 could negatively regulate the IL-6 signal. Recently, gp130 has been shown to be involved in the signaling processes of oncostatin M, leukemia inhibitory factor, and ciliary neurotropic factor, in addition to those of IL-6. Recombinant sgp130 showed inhibitory effect on the biologic function of such cytokines. This work implies physiologic roles of naturally produced serum sgp130 in modulating signals through gp130.

Animals↗

PubMed1993

Alboaggregin-B and botrocetin, two snake venom proteins with highly homologous amino acid sequences but totally distinct functions on von Willebrand factor binding to platelets.

Alboaggregin-B (AL-B) (Peng et al., Biochemistry (1991) 30, 11529-11536) was highly purified from the snake venom of Trimeresurus albolabris and characterized structurally and functionally, comparing with botrocetin, another snake venom protein recently characterized (Usami et al., Proc. Natl. Acad. Sci. USA (1993) 90, 928-932). Both the venom proteins are a heterodimer and show a high degree of sequence homology to each other and also to C-type lectins. Botrocetin specifically binds to von Willebrand factor (vWF), whereas AL-B binds to platelet glycoprotein (GP) Ib without affecting the binding of botrocetin to vWF. The binding of AL-B to GPIb does not potentiate the platelet aggregation even by exogenous fibrinogen, suggesting that AL-B binding to GPIb does not activate GPIIb/IIIa complex.

Amino Acid Sequence↗

PubMed1993

A factor VIII neutralizing monoclonal antibody and a human inhibitor alloantibody recognizing epitopes in the C2 domain inhibit factor VIII binding to von Willebrand factor and to phosphatidylserine.

A neutralizing monoclonal antibody, NMC-VIII/5, recognizing the 72 kDa thrombin-proteolytic fragment of factor VIII light chain was obtained. Binding of the antibody to immobilized factor VIII (FVIII) was completely blocked by a light chain-specific human alloantibody, TK, which inhibits FVIII activity. Immunoblotting analysis with a panel of recombinant protein fragments of the C2 domain deleted from the amino-terminal or the carboxy-terminal ends demonstrated binding of NMC-VIII/5 to an epitope located between amino acid residues 2170 and 2327. On the other hand, the epitope of the inhibitor alloantibody, TK, was localized to 64 amino acid residues from 2248 to 2312 using the same recombinant fragments. NMC-VIII/5 and TK inhibited FVIII binding to immobilized von Willebrand factor (vWF). The IC50 of NMC-VIII/5 for the inhibition of binding to vWF was 0.23 micrograms/ml for IgG and 0.2 micrograms/ml for F(ab)'2. This concentration was 100-fold lower than that of a monoclonal antibody NMC-VIII/10 which recognizes the amino acid residues 1675 to 1684 within the amino-terminal portion of the light chain. The IC50 of TK was 11 micrograms/ml by IgG and 6.3 micrograms/ml by F(ab)'2. Furthermore, NMC-VIII/5 and TK also inhibited FVIII binding to immobilized phosphatidylserine. The IC50 for inhibition of phospholipid binding of NMC-VIII/5 and TK (anti-FVIII inhibitor titer of 300 Bethesda units/mg of IgG) was 10 micrograms/ml.

Antibodies, Monoclonal↗

PubMed1993

Primary structure of two-chain botrocetin, a von Willebrand factor modulator purified from the venom of Bothrops jararaca.

The complete amino acid sequence and location of the disulfide bonds of two-chain botrocetin, which promotes platelet agglutination in the presence of von Willebrand factor, from venom of the snake Bothrops jararaca are presented. Sequences of the alpha and beta subunits were determined by analysis of peptides generated by digestion of the S-pyridylethylated protein with Achromobacter protease I or alpha-chymotrypsin and by chemical cleavage with cyanogen bromide or 2-(2'-nitrophenylsulfenyl)-3-methyl-3-bromoindolenine. Two-chain botrocetin is a heterodimer composed of the alpha subunit (consisting of 133 amino acid residues) and the beta subunit (consisting of 125 amino acid residues) held together by a disulfide bond. Seven disulfide bonds link half-cystine residues 2 to 13, 30 to 128, and 103 to 120 of the alpha subunit; 2 to 13, 30 to 121, and 98 to 113 of the beta subunit; and 80 of the alpha subunit to 75 of the beta subunit. In terms of amino acid sequence and disulfide bond location, two-chain botrocetin is homologous to echinoidin (a sea urchin lectin) and other C-type (Ca(2+)-dependent) lectins.

Amino Acid Sequence↗

PubMed1993

Genomic cloning of the rat histamine H1 receptor.

A rat histamine H1 receptor gene which lacked introns was isolated from a rat genomic library using recently cloned bovine histamine H1 receptor cDNA [Yamashita et al., Proc. Natl. Acad. Sci. USA, 88, 11515-11519 (1991)]. The receptor protein deduced from this isolated gene was composed of 486 amino acids and showed characteristic properties of G protein-coupled receptors. At the 5'-flanking region of the receptor gene, we have located potential TATA box sequences and consensus sequences for the glucocorticoid response element and AP-2 element. After being subcloned into a mammalian expression vector, the isolated gene was transfected to C6 glioma cells. These cells showed significant binding toward [3H]mepyramine. The binding was inhibited by H1 antagonists or histamine. The mode of this binding was comparable to the binding of membranes derived from rat tissues toward [3H]mepyramine. Northern blot analysis detected a 3.0 kb nucleotide band for histamine H1 receptor mRNAs from rat brain and small intestine when these mRNAs were hybridized with the isolated rat H1 gene. The present results demonstrate the isolation of the rat histamine H1 receptor gene.

Amino Acid Sequence↗

PubMed1993

Autoimmunity during alpha-interferon therapy for chronic hepatitis C.

One hundred twenty-five patients with chronic hepatitis C were treated with natural IFN alpha or recombinant IFN alpha-2a, daily doses of 3 MU or 9 MU, respectively. IFNs were given 6 times a week for the first 2 weeks followed by thrice weekly administration for 12 weeks or more. ANA, TMA, AMA and anti-DNA antibody newly developed in 8, 1, 2 and 1 patient, respectively. Furthermore, we encountered some cases in which underlying autoimmune disorders were thought to be exacerbated by IFNs. It is important to pay sufficient attention to the development of autoimmune diseases in IFN therapy for chronic hepatitis C.

Adult↗

PubMed1993

Increase in serotonin levels in the dog ileum and blood by cisplatin as measured by microdialysis.

Involvement of ileal and circulating serotonin (5-HT) levels in cisplatin-induced emesis was examined using a microdialysis technique and an extraction method in dogs. The 5-HT levels in the ileal dialysate were increased to 232-294% of the basal level from 100 to 180 min after cisplatin administration (3 mg/kg, i.v.) and had returned to the basal level 280 min after dosing. The 5-HT levels in the blood dialysate were increased to 424-2165% from 140 to 180 min after dosing. The concentrations of 5-HT determined by HPLC following extraction were increased to 271% in the ileal mucosa and to 478% in plasma 3 hr after dosing. In immunohistochemistry, the number of 5-HT-immunoreactive cells was increased to 166% in the ileal mucosa following cisplatin treatment. These results strongly suggest that increases in the release and synthesis of 5-HT in the gut, probably in the enterochromaffin cells, are intimately involved in cisplatin-induced emesis.

Animals↗

PubMed1993

The negative inotropic effects of amiodarone on isolated guinea pig heart: a possible role of Na(+)-Ca2+ exchange.

1. The negative inotropic effects of amiodarone (AM) were studied in isolated, isometrically contracting ventricular papillary muscles from guinea pigs. 2. AM, 4.4 x 10(-5) M, significantly decreased ouabain (10(-6) M)-induced increase in the developed tension. 3. Manganese (10(-2) M), a partial blocker of Na(+)-Ca2+ exchange, attenuated the AM's negative inotropy. 4. Theophylline (1.5 x 10(-2) M), an inhibitor of phosphodiesterase, produced a marked increase in the tension (about twice compared to the ouabain effect). 5. However, the magnitude of decrease by AM in the tension in the presence of theophylline was similar to that in the case of ouabain. 6. Tetrodotoxin (TTX) decreased the contraction by about a half, and then subsequent addition of AM in the presence of TTX led to a further decrease in the tension. 7. Eventually co-existence of TTX and AM led to a decrease in tension of same degree, compared to the decrease in tension by AM alone. 8. The results suggest that a large portion of negative inotropic action of AM may, at least, reflect interference with the Na(+)-Ca2+ exchange mechanism. 9. This interference with the Na(+)-Ca2+ exchange mechanism may exert a strong negative inotropic effect of the drug, in combination with a decrease in Ca2+ influx via Ca2+ channels and/or an impairment of Ca(2+)-sequestration.

Amiodarone↗

PubMed1993

Metabolic fate of endotoxin and blood tumour necrosis factor levels in rats with acute and chronic alcohol loading.

To investigate the metabolic fate of endotoxin in alcoholics and its possible relationship to cytokines and liver injury, we administered a low-dose radiolabelled endotoxin to rats given alcohol in various conditions and studied the organ distribution of endotoxin and measured plasma levels of tumour necrosis factor (TNF). In the chronic alcohol-fed rats (Lieber-DeCarli liquid diets for 6 weeks) 3H-endotoxin was rapidly cleared by the liver and excreted into faeces. However, the endotoxin clearance was decreased after an acute ethanol load to rats (5 mg/g body wt ethanol i.p.) or in the chronic ethanol-fed rats with an additional 5 mg/g body wt ethanol load. Plasma TNF was not elevated in the control or in the acute ethanol load rats, slightly elevated in the chronic ethanol-fed rats and markedly elevated in the chronic ethanol-fed rats with an additional high-dose ethanol load. Serum GPT was elevated only in the chronic ethanol-fed rats with an additional high-dose ethanol. In conclusion, an additional administration of a high dose ethanol to chronic alcohol-fed rats led to decrease of endotoxin clearance and elevation of plasma TNF, which may play an important role in the pathogenesis of alcoholic hepatitis.

Alcoholic Intoxication↗

PubMed1993

Effect of alcohol on the functions of Kupffer cells and splenic macrophages in rats.

Uptake of endotoxin and production of tumor necrosis factor (TNF) by Kupffer cells and splenic macrophages were measured in chronically alcohol-fed rats. Twenty male Sprague-Dawley rats, weighing 200-250 g, were pair-fed by isocaloric control and ethanol-containing Lieber-DeCarli liquid diets for 6 weeks. Endotoxin uptake and TNF production of Kupffer cells and splenic macrophages in the chronic ethanol load-group were significantly (P < 0.001) greater than those in the control group. The increase in endotoxin uptake was more prominent in Kupffer cells and the increase in TNF production was more marked in splenic macrophages in the chronic ethanol group. When these cells were precultured in the medium containing 10-100 mM ethanol, the endotoxin uptake and TNF production of Kupffer cells isolated from control and chronic ethanol-fed rats were decreased in proportion to the concentration of ethanol in the culture medium. However, the addition of ethanol to the culture medium did not affect the endotoxin uptake and TNF production of splenic macrophages. These results support the hypothesis that the splenic macrophages are important for endotoxin uptake, and excessive production of TNF in rats given large amounts of alcohol.

Alcoholism↗

PubMed1993

Molecular cloning of the guinea-pig histamine H1 receptor gene.

The histamine H1 receptor gene was isolated from a guinea-pig gene library. The gene contains no introns and encodes a protein of 488 amino acid residues. The structure of the guinea-pig histamine H1 receptor is predicted to contain seven putative transmembrane regions, which are similar to those of receptors coupling with GTP binding proteins. Although the third intracellular domain, the predicted binding site for the GTP binding protein, showed only 50% identity with those of the bovine and rat H1 receptors, the expressed guinea-pig H1 receptor was fully able to bind with [3H]mepyramine. Northern blot analysis indicated that the cerebrum, cerebellum, lung, adrenal, intestine, and heart expressed 3.3 kb guinea-pig H1 receptor mRNA. Expression of histamine H1 mRNA of guinea-pig peripheral organs was greater than that of rat organs, suggesting the high sensitivity of guinea-pig organs as to histamine is due to the contents of histamine H1 receptor mRNA. In addition, the lung, adrenal, intestine, and heart expressed 3.9 kb mRNA. In situ hybridization showed that the hippocampus, cerebral cortex, thalamus, and granular layer of the cerebellum each contained a large amount of histamine H1 receptors. Southern blot analysis showed that there was another gene quite similar to the cloned histamine H1 receptor gene.

Amino Acid Sequence↗

PubMed1993

Metastasis of hepatocellular carcinoma to the colon demonstrated by Tc-99m PMT scintigraphy.

A 57-year-old man was found to have a tumor in the ascending colon after hepatic segmentectomy for ruptured hepatocellular carcinoma. Colonoscopy was performed, and metastasis of the hepatocellular carcinoma to the ascending colon was suspected based on the biopsy specimens obtained from the tumor. On hepatobiliary scintigraphy using Tc-99m PMT performed to confirm this diagnosis, Tc-99m PMT was clearly observed to accumulate in the tumor. Thus, the tumor was diagnosed as metastasis of hepatocellular carcinoma.

Carcinoma, Hepatocellular↗

PubMed1993

Histamine content, synthesis and degradation in human nasal mucosa.

Histamine content and enzyme activities of histamine metabolism, histidine decarboxylase (HDC), histamine N-methyltransferase (HMT) and histaminase (diamine oxidase, DAO) in human nasal mucosa were determined with a highly sensitive and specific fluorescent method which was combined with high performance liquid chromatography. Histamine content and HDC activity were determined in 10 specimens of nasal polyp, nine specimens of maxillary sinus and five specimens of inferior turbinate. HMT and histaminase activities were determined in 15 specimens of nasal polyp, nine specimens of maxillary sinus and five specimens of inferior turbinate obtained during surgical therapy. Histamine and activities of HDC, HMT and histaminase were detected in all specimens except the case of histaminase activity in one specimen of nasal polyp. The mean values of histamine content and activities of HDC, HMT and histaminase of human nasal mucosa were 137.3 nmol/g wet weight, 26.3 fmol/min/mg protein, 26.4 pmol/min/mg protein and 0.5 pmol/min/mg protein, respectively. Histamine content in the mucosal tissue of the maxillary sinuses was significantly higher than that of nasal polyps or inferior turbinates. There were no significant differences in HDC activities among three kinds of nasal mucosa. Activities of HMT and histaminase, including their kinetic constants (Km and Vmax values for histamine) indicated that HMT has a greater potential than histaminase for histamine degradation in the human nasal mucosa. The presence of these enzymes suggests that these activities constitute an important modulating factor in histamine mediated allergic and inflammatory reactions in human nasal mucosa.

Adolescent↗

PubMed1993

Histamine content, synthesis and degradation in nasal mucosa and lung of guinea-pigs treated with toluene diisocyanate (TDI).

We have reported the presence of a histamine synthesizing enzyme, histidine decarboxylase (HDC), and histamine degrading enzymes, histamine N-methyltransferase (HMT) and histaminase (diamine oxidase, DAO) in human nasal mucosa and the histamine content of the mucosa. In this study, we demonstrate the influences of the toluene diisocyanate (TDI) treatment on the histamine content and these enzyme activities in guinea-pigs as an animal model of respiratory hypersensitivity. Application of TDI to the nasal vestibuli induced intense nasal allergy-like and mild asthma-like responses in TDI-sensitized guinea pigs. Increases in the histamine content and HDC and HMT activities were observed in the nasal mucosa and lung of TDI-sensitized guinea pigs. No apparent changes in the histaminase activities were observed in either the nasal mucosa or the lung. These data suggest that the turnover rate of histamine is increased in the nasal mucosa and the lung of guinea pigs with respiratory hypersensitivity.

Amine Oxidase (Copper-Containing)↗

PubMed1993

Roles of endothelin-1 and nitric oxide in the mechanism for ethanol-induced vasoconstriction in rat liver.

This study was designed to investigate the mechanism for ethanol-induced hepatic vasoconstriction in isolated perfused rat liver. Upon initiation of ethanol infusion into the portal vein at concentrations ranging from 25 to 100 mM, portal pressure began to increase in a concentration-dependent manner and reached maximal levels in 2-5 min (initial phase), followed by a gradual decrease over the period of ethanol infusion (escape phenomenon). Endothelin-1 antiserum significantly inhibited this ethanol-induced hepatic vasoconstriction by 45-80%. Cessation of infusion of endothelin-1 antiserum was followed by a subsequent increase in portal pressure. On the other hand, when a nitric oxide synthesis inhibitor, NG-monomethyl-L-arginine (L-NMMA), was infused into the portal vein simultaneously with ethanol, the initial phase of the response of portal pressure to ethanol was not altered and the peak values of portal pressure remained unchanged. However, after the peak increase in portal pressure, the rate of decrease was less than in the absence of L-NMMA. Thus, L-NMMA diminished the escape phenomenon and sustained the vasoconstriction. This study supports the hypothesis that two endothelium-derived vasoactive factors, endothelin-1 and nitric oxide, regulate hepatic vascular tone in the presence of ethanol.

Animals↗

PubMed1993

Histamine metabolism in nasal polyps.

We attempted to determine the relationship of nasal polyps to histamine (HA) metabolism. Compared to that in allergy-related nasal polyps and infection-related nasal polyps, the level of HA in aspirin-induced asthma-related polyps was significantly lower. Large differences between the groups were not observed in HA-synthesizing enzyme activity, but degradative enzyme activity was much higher in aspirin-induced asthma-related polyps than in other types of nasal polyps tested. These findings suggest the possibility that the amount of HA in polyps associated with aspirin-induced asthma was less because of greatly enhanced degradation. We found, in addition, that in nasal tissues such as polyps, histamine-N-methyl transferase, rather than histaminase, was the principal degradative enzyme.

Amine Oxidase (Copper-Containing)↗

PubMed1993

48,XXYY syndrome associated with acromegaloidism.

We report a case of double male syndrome, a type of Klinefelter's syndrome with 48,XXYY chromosome, associated with acromegaloidism. Although the patient presented acromegalic appearance, he did not show hypersecretion of growth hormone (GH). GH provocation tests revealed a rather low GH responses or no responses. After testosterone therapy, the GH responses were normalized except to Insulin tolerance test (ITT). On the other hand, the plasma corticotropin (ACTH) and cortisol levels were decreased paradoxically after hypoglycemia. Testosterone therapy did not restore this ACTH response. It was speculated that these abnormal GH and ACTH responses to hypoglycemia might indicate another congenital anomaly.

Acromegaly↗