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Biomedical subjects

K Haraguchi

Publications and source records attributed to K Haraguchi.

At least 91 records · Page 5Linked to original sources
PubMed1997

[The condition of PCBs and PCDFs in the blood of Yusho patients 20 years after the onset].

Blood samples of Yusho and control persons were analyzed for individual congeners of PCDDs, PCDFs, and PCBs by high resolution GC/MS. Concentrations of 2,3,4,7,8-penta-CDF, 1,2,3,4,7,8-hexa-CDF and 2,3,3',4,4',5-hexa-CB in Yusho blood were up to 56 times higher than the corresponding concentrations in the control blood. These high concentrations have persisted for 23 years after the incident. Concentrations of 3,3',4,4',5-penta-CB and 2,3',4,4',5-penta-CB in some Yusho blood were lower than the control blood. In Yusho blood, 2,3,4,7,8-penta-CDF contributed the highest toxicity (TEQ 77-248 ppt in lipid) among the congeners determined and toxic contribution of PCDFs was very large (41-77%) in the chlorinated pollutants. Thirty PCB congeners were identified in the blood of Yusho patients in 1996 by GC/MS. The average total PCB concentration in Yusho blood were 4.9 times higher than that of the controls. Characteristic PCB congeners in Yusho patients were 2,2',3,4,4',5-hexa-CB, 2,3,3',4,4',5-hexa-CB and 2,3,3',4,4',5'-hexa-CB and their concentration ratios to the controls were 8-19.

Adult↗
PubMed1997

[Tissue distribution of methylsulfonyl metabolites derived from Kanechlor 400 in mice].

Kanechlor 400, which caused the "Yusho disease", was i.p. administered to mice and methylsulfonyl (MeSO2) metabolites were investigated with respect to the concentration in liver and lung during 28 days after the administration. Major components were 3- and 4-MeSO2 derivatives from seven PCBs (IUPAC no. #31, #49, #64, #70, #101, #110, #132). In the liver, similar concentration ratio of 3- and 4-MeSO2 derivatives was observed, whereas seven 4-MeSO2 derivatives were selectively retained in the lung. Methylsulfone metabolites of triCB (#31) were rapidly formed and eliminated. The highest concentration of the metabolites in the lung was 4-MeSO2-2, 2', 4', 5-tetraCB. Concentration ratio of MeSO2-CBs to residual PCBs was 1:2.1 in the liver whereas 4.6:1 in the lung 28 days after the administration.

Animals↗
PubMed1997

Comparative study on formation of hydroxy and sulfur-containing metabolites from different chlorinated biphenyls with 2,5-substitution in rats.

2,4',5-Trichlorobiphenyl (TriCB), 2,3',4',5-tetrachlorobiphenyl (TetraCB), 2,2',4',5,5'-pentachlorobiphenyl (PentaCB), and 2,2',3',4',5,5'-hexachlorobiphenyl (HexaCB) were studied with regard to the fecal excretion and tissue distribution of their metabolites after intraperitoneal injection to rats. Major fecal metabolites were 3- and 4-hydroxy and 3- and 4-methylthio derivatives, the substitution ratios depending largely on the degree of chlorination. As the degree of chlorination increased, hydroxy products were more efficiently excreted, whereas the formation of methylthio metabolites greatly decreased. As a result, the excretion ratios of methylthio and hydroxy products varied with 2.8 for TriCB, 1.3 for TetraCB, 0.04 for PentaCB, and 0.02 for HexaCB. The 3-/4-hydroxy substitution ratios were 0.6 for TriCB, 1.4 for TetraCB, 21 for PentaCB, and 35 for HexaCB, whereas the 3-/4-methythio substitution ratios were 1.2 for TriCB, 0.8 for TetraCB, 0.18 for PentaCB, and 0.12 for HexaCB. The formation rate of 3- and 4-methylthio metabolites from each congener was correlated to the accumulation and distribution of 3- and 4-methylsulfonyl derivatives in tissues. The tissue/blood concentration ratios of methylsulfonyl metabolites showed that the 3-methylsulfonyl derivatives from higher chlorinated biphenyls had a relatively high affinity for liver and adipose tissue, whereas the 4-methylsulfonyl derivatives were selectively retained in the lung in all cases.

Animals↗
PubMed1997

Tissue distribution kinetics of a new nonsteroidal 5 alpha-reductase [correction of 5 A-reductase] inhibitor, 4-[3-[3-[bis(4-isobutylphenyl)methylamino]benzoyl]-1H-indol-1-YL ]-butyric acid, in rats.

The disposition of a new nonsteroidal 5alpha-reductase inhibitor, 4-[3-[3-[bis(4-isobutylphenyl)methylamino]benzoyl]-1H-indol-1-yl]-butyric acid (FK143), was investigated in rats. After intravenous administration of FK143 at 1 and 5 mg/kg, total body clearance, elimination half-life, and volume of distribution at steady-state were, respectively, 6.96 and 8.76 ml/min/kg, 10.31 and 9.83 hr, and 4.11 and 3.33 liters/kg. There were no essential differences between the two doses in any parameters. The serum protein binding in vitro was very high (>99%). The unidirectional uptake clearance (CL1) to 13 tissues was determined by integration plot until 10 min after intravenous administration of 1 mg/kg. CL1 values were much smaller than blood flow rate in all tissues, including the prostate, the target organ, indicating that FK143 was transported from blood to tissues by a membrane-limited process. Since the elimination rates of FK143 from the liver, kidney, lung, epididymis, seminal vesicle, and prostate were slower than from the blood, the efflux rate constant (k2) and rate constants at a binding compartment (k3 and k4) were assumed in the pharmacokinetic model. A correlation was found between the binding potential of binding compartment (k3/k4) and V(max) of steroid 5alpha-reductase, the target enzyme, suggesting that the levels of 5alpha-reductase activity or that of associated substances are a primary determinant of the specific binding of FK143 in these tissues.

5-alpha Reductase Inhibitors↗
PubMed1996

Functional expression of thyrotropin receptor in differentiated 3T3-L1 cells: a possible model cell line of extrathyroidal expression of thyrotropin receptor.

Thyrotropin receptor (TSHR) in extrathyroidal tissue, especially fat tissue, is supposed to have important roles in the development of extrathyroidal manifestations of Graves' disease. However, the molecular mechanism of TSHR expression is not known. Expression of TSHR mRNA and TSH-dependent cAMP production were observed in differentiated but not in undifferentiated 3T3-L1 cells. Maximal expression was obtained when the cells were differentiated in the presence of insulin, dexamethasone, and isobutylmethylxanthine (IBMX). Dexamethasone and IBMX were indispensable for the first three days. On the other hand, after day 4, insulin was indispensable for the expression of TSHR. 3T3-L1 cell is the first non-thyroidal cell line reported that expresses TSHR and whose expression can be induced. 3T3-L1 cell can be a good model to investigate the mechanism of expression of TSHR and extrathyroidal manifestations of Graves' disease.

1-Methyl-3-isobutylxanthine↗
PubMed1996

Catalepsy induced by manidipine, a calcium channel blocker, in mice.

Manidipine, a calcium channel blocker, is a piperazine derivative similar to flunarizine or cinnarizine, which are known to induce parkinsonism. Since it has been reported that manidipine can worsen parkinsonian symptoms in a patient with Parkinson's disease, we have evaluated catalepsy in manidipine-treated mice and compared this with flunarizine-and haloperidol-induced catalepsy. The minimum dose at which manidipine induced catalepsy was 200 times higher than that of haloperidol whereas for flunarizine, the minimum dose was 50 times higher than that for haloperidol. Manidipine, flunarizine and haloperidol occupied both dopamine D1 and D2 receptors and D2-receptor occupancy was higher than D1-receptor occupancy. These results suggest that the blockade of dopamine D1 and D2 receptors by drugs and the drug-induced catalepsy are related to the structure (piperazinyl substituent) of the drugs.

Animals↗
PubMed1996

Differentiation of rat preadipocytes is accompanied by expression of thyrotropin receptors.

To investigate the regulation of expression of the TSH receptor (TSHR) in extrathyroidal tissues, the level of TSHR messenger RNA (mRNA) and TSH-dependent signal transduction were determined in isolated rat adipocytes and cultured preadipocytes. The epididymal, sc, and perirenal, but not the interscapular brown adipose tissues, possessed TSHR mRNA and increased cAMP responses to TSH and were thus used as the source of preadipocytes. Morphological analysis revealed that the combination of insulin and T3 most effectively caused the differentiation of rat preadipocytes. These differentiated preadipocytes exhibited increased cAMP production in response to TSH. The addition of FCS to the culture medium inhibited the differentiation of rat preadipocytes as well as TSH-stimulated production of cAMP. The stimulation of differentiation was associated with an increased expression of TSHR mRNA levels, whereas the inhibition of differentiation was associated with a decreased expression of TSHR mRNA, as detected by Northern blot analysis. The results indicate that the expression and function of the TSHR in cultured rat preadipocytes are closely related to cellular differentiation. Cultured rat preadipocytes appear to provide a useful system for studying the mechanism of extrathyroidal expression of TSHR.

Adipocytes↗
PubMed1996

A case of calcification of the cervical ligamentum flavum.

We report a case of cervical myelopathy caused by the calcification of the cervical ligamentum flavum. A 42-year-old woman with gait disturbance and an episode of dysuria was transferred to our hospital on June 30, 1994. Neurological examination revealed only a mild right hemiparesis. A plain neck X-ray and a tomogram revealed a nodular calcification in the posterior part of the spinal canal at the level of C5/6. Three dimensional computed tomography clearly demonstrated that the mass consisted of three nodular structures on the vertebral lamina. Magnetic resonance images demonstrated severe compression of the spinal cord by the mass whose intensity was low. The mass was removed en bloc together with the ligamentum flavum and C5 and C6 lamina. The mass showed no continuity to the dura mater. The calcification was confined within the ligament. The patient's neurological deficits were resolved two weeks after the surgery. X-ray diffraction study demonstrated the component of the mass was found to be pure hydroxyapatite. Clinical features of calcification of the ligamentum flavum are reviewed from 85 reported cases including ours, and the difference between this calcification and the ossification of the ligament is emphasized. Calcification of the ligamentum flaum is a distinct clinical entity.

Adult↗
PubMed1995

Cloning and functional expression of a thyrotropin receptor cDNA from rat fat cells.

Thyrotropin receptor (TSH-R) has been thought to be thyroid-specific, but, by Northern blot analysis, we found that rat adipose tissue expressed TSH-R mRNAs in amounts approaching those in the thyroid. To investigate the function of TSH-R from adipose tissue, we screened a rat fat cell lambda gt11 cDNA library for TSH-R sequences using a 32P-labeled rat thyroid TSH-R cDNA as a probe. Among 10(6) plaques, we obtained four positive clones. Sequencing of these cDNAs has revealed that two of them (F alpha and F beta) contained both initiation and termination codons. Comparison of F alpha with the thyroid TSH-R cDNA sequence revealed that F alpha was almost identical to the thyroid TSH-R, except that nucleotides 1041 and 1277 were changed from A to G and from C to T, respectively. In contrast, we found that F beta contained 21 novel nucleotides between nucleotides 467 and 468 of the thyroid TSH-R cDNA, encoding an additional 7 amino acids. However, when we prepared mRNA from adipose tissue and transcribed it into cDNA, we failed to amplify the F beta type of TSH-R cDNA by polymerase chain reaction, suggesting that F beta mRNAs are rare in the tissue. We then ligated F cDNAs into pSG5 and transfected them with pSV2-neo into Chinese hamster ovary (CHO)-K1 cells. TSH stimulated cAMP formation in CHO-F alpha cells in a manner similar to that in CHO cells transfected with thyroid TSH-R cDNA. In contrast, no increase of cAMP was observed in CHO-F beta cells. IgG from patients with Graves' disease (n = 4) showed thyroid-stimulating antibody activity only in CHO-F alpha cells (1288-4582%). In addition, CHO-F alpha cells and CHO cells transfected with thyroid TSH-R showed similar 125I-TSH binding activity. These results indicate that the fat cell expresses high levels of a TSH-R whose function is indistinguishable from that in the thyroid and suggest that the TSH-R autoantibody plays an important role in the pathogenesis of the extrathyroidal manifestations of Graves' disease.

Adipose Tissue↗
PubMed1995

Induction of hepatic microsomal drug-metabolizing enzymes by methylsulphonyl metabolites of polychlorinated biphenyl congeners in rats.

The effect of methylsulphonyl (MeSO2) metabolites of 2,3',4',5-tetrachlorobiphenyl (tetraCB) (IU-70), 2,2',3',4',5-pentachlorobiphenyl (pentaCB) (IU-87), 2,2',4',5,5'-pentaCB (IU-101) and 2,2',3',4',5,5'-hexachlorobiphenyl (hexaCB) (IU-141), on the hepatic microsomal drug-metabolizing enzyme system was investigated in rats. The administration of 3-MeSO2-2,3',4',5-tetraCB (10 mumol/kg), 3-MeSO2-2,2',3',4',5-pentaCB (0.5 mumol/kg), 3-MeSO2-2,2',4',5,5'-pentaCB (0.5 mumol/kg) and 3-MeSO2-2,2',3',4',5,5'-hexaCB (2 mumol/kg) to rats significantly increased the contents of cytochromes P-450 and b5 and the activities of aminopyrine N-demethylase, 7-ethoxycoumarin O-deethylase and benzo[a]pyrene hydroxylase. From these results, it is suggested that the 3-MeSO2 derivatives studied are possibly potent phenobarbital-like inducers of microsomal drug-metabolizing enzymes. On the other hand, 4-MeSO2-2,3',4',5-tetraCB, 4-MeSO2-2,2',3',4',5-pentaCB, 4-MeSO2-2,2',4',5,5'-pentaCB and 4-MeSO2-2,2',3',4',5,5'-hexaCB had almost no effect on both cytochrome contents and these enzyme activities. After 96 h, following administration of 2,3',4',5-tetraCB, 2,2',3',4',5-pentaCB, 2,2',4',5,5'-pentaCB and 2,2',3',4',5,5'-hexaCB (342 mumol/kg each), significant increases in contents of these two cytochromes and in activities of these enzymes were observed. The relationship between liver concentrations of 3-MeSO2-PCBs after administration of four PCB congeners and that after administration of their 3-MeSO2 derivatives, and increases in the contents of both cytochromes and activities of drug-metabolizing enzyme suggests that the 3-MeSO2 metabolites derived from PCBs studied play an important role in the induction of the drug-metabolizing enzymes by the parent PCB congeners.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1995

Characterization of hepatic microsomal cytochrome P-450 from rats treated with methylsulphonyl metabolites of polychlorinated biphenyl congeners.

The inducing potency of 3-methylsulphonyl(MeSO2)-2,2',4',5,5'-pentachlorobiphenyl (pentaCB), which was one of the major MeSO2 metabolites of polychlorinated biphenyls (PCBs) present in seal blubber, on the hepatic drug metabolizing enzyme activities was examined in comparison with that of the parent compound and phenobarbital (PB). The inducing fashion of the above enzymes and changes in the contents of PB-inducible P-450 forms by 2,3',4',5-tetrachlorobiphenyl (tetraCB) (IU-70), 2,2',3',4',5-pentaCB (IU-87), 2,2',4',5,5'-pentaCB (IU-101) and 2,2',3',4',5,5'-hexachlorobiphenyl (hexaCB) (IU-141), and their MeSO2 metabolites were investigated in rats. Administration at various doses (0.2-1.0 mumol/kg) of 3-MeSO2-2,2',4',5,5'-pentaCB produced nearly dose-related increases in the hepatic concentration of this methyl sulphone, in the contents of cytochromes P-450 and b5, and in activities of aminopyrine N-demethylase, 7-ethoxycoumarin O-deethylase and benzo[a]pyrene hydroxylase of liver microsomes. Major PB-inducible forms, CYP2B1, CYP2B2, CYP3A2 and CYP2C6 were induced with four PCBs (342 mumol/kg) and their 3-MeSO2 metabolites (0.5-10 mumol/kg), indicating that 3-MeSO2 metabolites were strong PB-type inducers of hepatic drug-metabolizing enzymes. 3-MeSO2-2,2',4',5,5'-pentaCB was an especially strong inducer. On the other hand, four PB-inducible forms of cytochrome P-450 were not induced with the 4-MeSO2 isomers. The relation between liver concentrations of the corresponding 3-MeSO2 derivatives and induction of four PB-inducible forms of cytochrome P-450 after administration of four PCBs and their 3-MeSO2 derivatives further confirmed that the 3-MeSO2 metabolites played an important role in the induction which parent PCB congeners caused on the hepatic drug-metabolizing enzyme system.

Animals↗
PubMed1995

The functional significance of the second extracellular loop of thyrotropin receptor in thyrotropin- and thyroid stimulating antibody-dependent signal transduction.

In order to determine the functional significance of the extracellular loop of human thyrotropin receptor (hTSHR), two peptides composed of eight amino acids were inserted into hTSHR by ligating synthetic oligonucleotides into +1811 NCol site of hTSHR cDNA. Mutant hTSHR cDNAs which encode a hydrophobic peptide (ATVLVVPM) and a hydrophilic peptide (GTTRTVAM) between +572 Met and +573 Asp were transfected into Chinese hamster ovary (CHO) cells to develop F-cell lines and R-cell lines, respectively. Of the resulting cloned cell lines, F-29 and R-9 were shown to express mutant hTSHs at the protein level by Western blotting and at the mRNA level by reverse transcription-polymerase chain reaction (RT-PCR). We show that neither thyrotropin (TSH) nor IgGs from patients with Graves' disease stimulated cAMP production by F-29 and R-9 cells. 125I-TSH binding study revealed that F-29 and R-9 cells do not bind TSH. Our data demonstrate that the mutations impaired TSH-binding and incapacitated the cells from responding to TSH. The evidence suggests that the second extracellular loop of hTSHR has an important role in TSH and thyroid stimulating antibody (TSAb)-dependent signal transduction.

Amino Acid Sequence↗
PubMed1995

Cloning and nucleotide sequence of the inulin fructotransferase (DFA I-producing) gene of Arthrobacter globiformis S14-3.

A gene encoding an inulin fructotransferase (DFA I-producing) [EC 2.4.1.200] from Arthrobacter globiformis S14-3 was cloned and the nucleotides sequenced, for the first time. The sequence indicated that the native enzyme protein is composed of 392 amino acid residues. The native enzyme is an extracellar enzyme produced in the culture supernatant of A. globiformis S14-3, but the nucleotide sequence of the gene lacks a sequence for signal peptide for secretion. The 1.5-kb DNA fragment encoding the gene was found to produce the active enzyme in the culture supernatant of an E. coli clone, under the control of the lac promoter of pUC119.

Amino Acid Sequence↗
PubMed1995

Desensitization to somatostatin analogue (Octreotide) observed in a patient with acromegaly.

We encountered a 33-year-old female patient with a pituitary growth hormone (GH)-secreting macroadenoma. The patient was treated with somatostatin analogue (Octreotide) in combination with bromocriptine for 2 months before a transsphenoidal adenomectomy was carried out. Octreotide (300-800 micrograms/day) in combination with bromocriptine was effective in reducing the size of the adenoma by 36%, but produced only a marginal decrease in serum GH. After the operation, bromocriptine alone (15 mg/day) did not lower the level of GH which was produced by residual adenoma tissue. When octreotide (200 micrograms/day) was resumed along with the bromocriptine one year after the operation, it effectively lowered serum GH for 6 months. Thereafter, octreotide therapy became ineffective with a concomitant rise in serum GH and somatomedin C, which was not accompanied by an increase in tumor size. This was a rare case of acromegaly that showed desensitization to octreotide after long-term treatment.

Acromegaly↗
PubMed1995

[Tissue retention of hydroxy and methylsulfonyl metabolites of 2, 2', 4, 4'-tetrachlorobiphenyl in rats].

Previously, we have identified a large number of methylsulfonyl metabolites in tissues of mink treated with Clophen A50. Most of them were found to be derived from CBs with a 2, 5-dichlorophenyl or a 2, 3, 6-trichlorophenyl ring. It is further necessary to investigate if CBs with a 2, 4-dichlorophenyl ring could be biotransformed to the sulfur-containing metabolites in animals. In the present study, 2, 2', 4, 4'-tetrachlorobiphenyl (TCB) was administered i.p. to rats, and liver, lung, kidney, adipose tissue and blood were analyzed for the unchanged CB and its metabolites. Both hydroxy and methylsulfonyl metabolites were detected in all tissues analyzed. Major metabolites were identified as 3-OH-2, 2', 4, 4'-TCB, 5-5-OH-2, 2', 4, 4'-TCB, 5-MeSO(2)-2, 2', 4, 4'-TCB and 6-MeSO(2)-2, 2', 4, 4'-TCB. Total level of the four metabolites was estimated to be 1.5 micrograms/g wet weight in the liver, corresponding to similar level of the unchanged CB. The concentration ratios of 3-OH- to 5-OH-TCB and 5-MeSO2- to 6-MeSO(2)-TCB were about 2:3 and 2:1, respectively, in liver and kidney. These results indicate that CBs with a 2, 4-dichlorophenyl ring can provide both hydroxy and methylsulfonyl metabolites that are retainable in tissues of rats.

Adipose Tissue↗
PubMed1995

[Change of PCDF and PCB concentrations in the blood of Yucheng and Yusho patients for 25 years].

The blood samples of 3 Yucheng patients collected 6-7 times from 1980 to 1993 and 5 Yusho patients collected 6-8 times from 1982 to 1993 were analyzed for congeners of polychlorinated dibenzofurans (PCDF) and polychlorinated biphenyls (PCB) by high resolution gas chromatography-mass spectrometry and gas chromatography-electron capture detection. In the blood of Yucheng patients, the high concentrations of 3 PCDF congeners, 2,3',4, 4',5-penta-CB and 5 PCB congeners were eliminated at half-lives of 2.4-2.9, 1.7 and 4.1-6.1 years, respectively, while in Yusho patients, 14 years after the incident, their half-lives were converted to longer times as observed 3.2-13.4, 24.0 and 13.7-34.2 years, respectively. In the same Yucheng and Yusho patients, the half-lives of the 5 PCB congeners were about twice longer than those of the 3 PCDF congeners. PCBs are more retainable than PCDFs in human blood.

Adult↗
PubMed1995

Effect of 2, 3, 4, 7, 8-pentachlorodibenzofuran and its analogues on induction of sister chromatid exchanges in cultured human lymphocytes.

We have been already contaminated with various chemicals including highly toxic organochlorine compounds such as 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD), 2, 3, 4, 7, 8-pentachlorodibenzofuran (PenCDF) and 3, 4, 5, 3', 4'-pentachlorobiphenyl (Co-PenCB). In this study, in order to evaluate the genotoxicity of the three chemicals, we have examined their effects on the induction of sister chromatid exchanges (SCEs), which has been frequently utilized as an indicator of biological and genetic damage due to exposure to carcinogens or mutagens, in cultured human lymphocytes in the absence or presence of 7, 8-benzoflavone (ANF) and the following results were obtained. 1) TCDD, PenCDF and Co-PenCB significantly increased the frequency of SCEs with almost the same dose-dependent manner in terms of the concentration of TCDD toxic equivalent. 2) 8 x 10(-5) MANF significantly enhanced the frequency of SCEs and the simultaneous treatment of ANF and either of TCDD, PenCDF or Co-PenCB seemed to exert an additive effect as SCEs inducer. 3) TCDD, PenCDF and Co-PenCB were considered to be very potent inducers of SCEs, because their 50% effective concentration in SCEs enhancement were only 5 to 10 times higher than the level of the adipose tissue in healthy Japanese, namely, 70ppt as TCDD. Consequently, the respective TCDD toxic equivalency factors of 0.5 and 0.2 for PenCDF and Co-PenCB seemed to be reasonable so far as the induction of SCEs was employed as an indicator of the genotoxic potency.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗