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.

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.

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.

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.

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.

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)

[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.

[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.

Influence of five methylsulphonyl PCB congeners on frequency of micronucleated cells in cultured human lymphocytes by cytokinesis block method

The lungs and blood of Yusho patients and healthy Japanese people have already been contaminated with methylsulphonyl polychlorinated biphenyls (MSF-PCBs) at relatively high concentration. Therefore, we should give due attention to their biological and toxicological effects to man. In this study, in order to mainly evaluate non-S-dependent genotoxicity of five MSF-PCB congeners, namely, 3-MSF-4, 5, 3', 4'-tetrachlorobiphenyl (TCB), 3-MSF-4, 5, 2', 3'-TCB, 3-MSF-2, 5, 2', 4', 5'-pentachlorobiphenyl (PenCB), 4-MSF-2, 5, 2', 3', 4'-PenCB and 4-MSF-2, 5, 2', 3', 5', 6'-hexachlorobiphenyl (HCB). We have examined their effects on the induction of micronucleated cells, which has been frequently used to estimate the dose of ionizing radiation and truly radiomimetic, non-S-dependent, clastogens, in cultured human lymphocytes in the absence or presence of 2, 3, 4, 7, 8-pentachlorodibenzofuran (PenCDF), 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) or 3, 4, 5, 3', 4'-pentachlorobiphenyl (Co-PenCB). The following results were obtained. 1) 4 x 10(-5) M7, 8-benzoflavone (ANF) significantly enhanced the frequency of micronucleated cells and all of the five MSF-PCB congeners failed to induce the formation of micronucleated cells at doses of 5.2 to 9.6 ppm, which were about 35,000 times higher than the concentrations in the lungs and adipose tissue of healthy Japanese people.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

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.

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.

Desensitization and internalization of a thyrotrophin receptor lacking the cytoplasmic carboxy-terminal region

To understand the functional significance of the carboxy-terminal half of the intracellular region of the human TSH receptor (hTSHR), a mutant hTSHR lacking amino acids from the carboxy-terminal to His726 was constructed. Wild type hTSHR cDNA and truncated hTSHR cDNA were subcloned into a eukaryotic expression vector, pRc/CMV, and transfected into Chinese hamster ovary cells to obtain cell lines which stably expressed hTSHRs at high levels. This allowed us to observe highly efficient coupling of hTSHR and adenylyl cyclase as well as desensitization and internalization of hTSHR. Despite the differences in potential phosphorylation sites and internalization signals, dose-dependent stimulation of adenylyl cyclase by TSH, TSH-dependent desensitization and the rate of hTSHR internalization were similar for wild type and truncated hTSHRs. We conclude that the carboxy-terminal half of the intracellular region of hTSHR does not have a major functional role in TSH-dependent signal transduction.

Structure of the rat thyroid transcription factor-1 (TTF-1) gene

TTF-1 is a homeodomain-containing thyroid transcription factor which activates the genes of thyroid specific protein, thyroglobulin, thyroid peroxidase and thyrotropin receptor. We have cloned the TTF-1 gene from rat liver genomic library, and the exon/intron organization and the structure of the 5' flanking region were determined. The clone contained the 5.2 kbp upstream sequence from translation initiation site, and we found that the gene has a single intron in the coding sequence. We found in the 5' flanking region the TTF-1 binding consensus sequence, CTCAAGC, at -175 to -169, which overlaps the consensus sequence of CAAT box, DNase I foot print analysis has revealed that the region is protected by nuclear extract from thyroid cells but not by the extract from the liver, suggesting that expression of the TTF-1 gene is autoregulated by TTF-1.

[The structure and function of the extracellular domain of human thyrotropin receptor]

Since the molecular cloning of human TSH receptor (TSHR), much efforts have been focused on determining the TSH or TSAb binding sites. Despite many conflicting data, there seems to be a consensus that TSH binds to the various parts of the extracellular domain of TSHR discontinuously. However, following questions are not yet answered 1) Is the binding to extracellular domain of TSHR sufficient to the signal transduction? 2) Is there any contribution of the extracellular loops to TSH binding? Using TSHR mutated at the first or the second extracellular loops, we propose that the extracellular loops are important for TSH binding and signal transduction.

Disruption of the first extracellular loop of thyrotropin receptor prevents ligand binding

In order to understand the function of the first extracellular loop of the human thyrotropin receptor (hTSHR), each of two peptides of nine amino acids was inserted into the first extracellular loop of hTSHR. hTSHR cDNA was subcloned into the eukaryotic expression vector, pRc/CMV (hTSHR/pRc/CMV). B-hTSHR/pRc/CMV, a mutant hTSHR cDNA which encodes a hydrophilic peptide insert (AGTTRRVAI) and C-hTSHR/pRc/CMV which encodes a hydrophobic peptide insert (ATVLVVPMI) between +486 Ileu and +487 Asp of hTSHR were transfected into Chinese hamster ovary cells to generate the B-1 and C-6 cell lines, respectively. Neither thyrotropin (TSH) nor thyroid stimulating antibody (TSAb) stimulated cAMP production by B-1 or C-6 cells. An 125I-TSH binding assay showed that neither cell line bound TSH. Our data demonstrated that these mutations impaired both TSH binding and cAMP production. This evidence suggests that the first extracellular loop of hTSHR may have a crucial role in the TSH- and TSAb-dependent signal transduction.

Thyrotrophin-dependent desensitization by Chinese hamster ovary cells that express the recombinant human thyrotrophin receptor

To determine whether thyrotrophin (TSH)-induced desensitization requires a thyroid-specific factor(s), the human TSH (hTSH) receptor was expressed in Chinese hamster ovary cells. The first incubation of the cells with TSH decreased the subsequent response of adenosine 3',5'-cyclic monophosphate to freshly added TSH in the second incubation. This homologous desensitization was observed as early as after 3 h of the first incubation. The lowest dose of TSH that elicited desensitization was 0.1 nmol/l. The desensitization was not overcome by adding higher doses of TSH in the second incubation. A 125I-labelled TSH-binding study revealed a decrease in the number of high-affinity binding sites but not in that of low-affinity binding sites. The data suggest that TSH-induced desensitization in hTSH receptor-transfected cells is caused, at least in part, by a decrease in the number of TSH receptors on the cell surface. The evidence demonstrates, contrary to an earlier report, that a thyroid-specific factor(s) is not required for hTSH receptor desensitization.

[Accumulation of hydroxylated PCB metabolites in blood]

In order to investigate some potential accumulate properties of hydroxylated PCB metabolites, blood and tissues such as livers, kidneys, lungs and adipose tissue from rats exposed to a commercial PCB (Aroclor 1254) were analyzed for hydroxylated PCBs (OH-PCBs). A large number of OH-PCBs were detected in the liver 1 day after exposure among which almost 13 have been identified in the blood. OH-PCBs were retained selectively in the blood probably due to binding between the OH-PCBs and a protein in serum. One major OH-PCB determined in rat blood was 4-OH-2', 3, 3', 4', 5-pentaCB formed from 2, 3, 3', 4, 4'-pentaCB after NIH shift. Blood of a grey seal from the Baltic also contained at least 8 OH-PCB congeners with 2 major compounds determined as 4-OH-2', 3, 3', 4', 5-pentaCB and 4-OH-2, 3, 3', 4', 5, 5'-hexaCB. Thus, 4-OH-2', 3, 3', 4', 5-pentaCB is the most retainable OH-PCB congener in blood from rats and seal. Human serum have also been found to contain a few number of OH-PCBs at concentration of 0.6 ng/g serum which corresponds to one fourth of PCB level.

[PCB methylsulfone accumulated in muscle of mink dosed with PCB (Clophen A50)]

The structural requirements of the parent PCBs for the formation of the retained PCB methylsulfones (MeSO2-CBs) were investigated in mink (Mustela vison) exposed to PCB (Clophen A50). Muscle was analyzed for the MeSO2-CBs, which were determined by comparison of synthesized reference compounds. Major unmetabolized CBs such as 2, 4, 5, 2', 4'-pentaCB, 2, 4, 5, 2', 3', 4'-hexaCB, 2, 4, 5, 2', 4', 5'-hexaCB and 2, 3, 4, 5, 2', 4', 5'-heptaCB were determined in high concentrations in the mink muscle. All these PCBs are substituted in the 2, 4, 5-positions of at least one of the phenyl rings. On the other hand, CBs with free meta/para-positions were readily metabolized. Thus, at least 25 MeSO2-CBs were detected at concentration of 16 micrograms/g in extracted lipids from the muscle, corresponding to one tenth of PCB levels. Most of the methyl sulfone metabolites were 3- and 4-MeSO2-CB isomers of PCBs known to be rapidly metabolized, e.g. 2, 4, 2', 5'-tetraCB, 2, 3, 6, 4'-tetraCB, 2, 5, 3', 5'-pentaCB, 2, 4, 5, 2', 5'-pentaCB, 2, 3, 4, 2', 5'-pentaCB, 2, 3, 6, 3', 4'-pentaCB, 2, 3, 6, 2', 4', 5'-hexaCB and 2, 3, 6, 2', 3', 4'-hexaCB. 3-MeSO2-2, 5, 2', 5'-tetraCB and 3-MeSO2-2, 5, 6, 2', 5'-pentaCB were also found to be retained in the muscle, but their isomeric 4-MeSO2-CBs were not detected. Both the 3- and 4-MeSO2-2, 5, 6, 2', 4', 5'-hexaCB isomers were identified in the muscle extracts while no MeSO2-CB metabolite originating from 2, 3, 2', 4', 5'-pentaCB were detected in the muscle. These results show the PCBs with at least one phenyl ring with 2, 5-dichloro- and 2, 3, 6-trichloro-substitution are strongly favored and may be considered a criterion for the formation of MeSO2-CBs accumulated in mink muscle. These observations are in accordance with MeSO2-CBs detected also in other mammals.

[Change of PCDF concentrations in the blood of Yusho patients in recent ten years]

The blood of 16 Yusho patients sampled from 1982 (14 years after the incident) to 1992 were analyzed for congeners of polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) by high resolution gas chromatography-mass spectrometry and gas chromatography with electron capture detection, respectively. Biological half-lives of PCDFs and PCBs were estimated by following the change of blood concentrations of the Yusho patients in the equation of 1-compartment model. The biological half-lives of 2, 3, 4, 7, 8-penta-CDF and 1, 2, 3, 4, 7, 8-hexa-CDF in 8 individuals varied from 6.0 to 76 years with median 11.7 years and from 4.8 to 26.5 years with median 7.0 years, respectively. The half-lives of 1, 2, 3, 4, 6, 7, 8-hepta-CDF in 4 individuals varied from 2.1 to 15 years. Concentrations of PCBs in 13 individuals were estimated to be slowly decreased and increased with several years half-life in about half-and-half numbers.

Stereo-controlled C-C bond formation at the anomeric position of uracil nucleosides

Stereoselective synthesis of 1'-carbon-substituted uracil nucleosides has been achieved through face-selective bromo-pivaloyloxylation of a 1',2'-unsaturated derivative and successive SnCl4-promoted nucleophilic substitution with organosilicon reagents. This constitutes the first example of C-C bond formation at the anomeric position of nucleosides.

A taxonomic review of the genus Microbispora by analysis of ribosomal protein AT-L30

We analyzed the ribosomal AT-L30 proteins from 13 type strains of species belonging to the genera Microbispora and Actinomadura. The electrophoretic mobilities of the AT-L30 preparations from Microbispora strains, as determined by two-dimensional polyacrylamide gel electrophoresis, revealed that the members of the genus Microbispora are phylogenetically homogeneous. The results of partial amino acid sequencing of AT-L30 preparations from several representative Microbispora strains supported the separation of the genus Microbispora from other related genera. The amino acid sequences of the AT-L30 proteins from strains of species belonging to the genus Actinomadura sensu stricto displayed a diversity that exemplified the low levels of amino acid sequence homology within the genus. This diversity was considered to be a characteristic typical of the genus Actinomadura.

Single subunit structure of the human thyrotropin receptor

We have produced rabbit antibody against a synthetic peptide corresponding to N-terminal region of the extracellular domain of human thyrotropin receptor (hTSH-R) (N peptide, aminoacid residues 29-57). Western blot analysis revealed that N-peptide antibody recognized recombinant hTSH-R stably expressing in CHO-K1 cells as a mol. wt. about 104 kDa regardless in the presence or absence of disulfide-reducing agent. The band was not detected in untransfected CHO-K1 cells and no band was also stained by the antibody absorbed with N-peptide. In a reducing condition, the antibody also bound the rat receptor from FRTL5 cells as the same molecular size (104 kDa). These results clearly indicate that TSH-R is composed of a single subunit and that two subunit model for the TSH-R may reflect artifactual proteolytic cleavage of the receptor during membrane preparation.

Beta 2-adrenergic receptor mRNA is overexpressed in neoplastic human thyroid tissues

The expression of beta 2-adrenergic receptor (AR) mRNA was investigated in normal and neoplastic human thyroid tissues. A combination of techniques for reverse transcribing mRNA into cDNA and the incorporation of 32P-gamma ATP into the polymerase chain reaction (PCR)-generated fragments allowed us to detect beta 2-AR mRNA in surgically excised thyroid specimens. The levels of beta 2-AR cDNA generated by PCR in thyroid adenomas and cancers were 3.3 and 6.9 times, respectively, as high as that of normal thyroid tissues. These findings suggest that the level of beta 2-AR mRNA is correlated with the extent of differentiation in neoplastic tissues. The present study provides new insights into the relationships between the AR-adenylate cyclase system and the regulation of the growth and differentiation in neoplastic human thyroid tissues.

Mouse submandibular gland prorenin-converting enzyme is a member of glandular kallikrein family

Mouse submandibular gland prorenin-converting enzyme (PRECE) consists of the two polypeptide chains of 17 and 10 kDa and cleaves mouse Ren-2 prorenin at a dibasic site to yield mature renin. Western blot analysis using an antiserum against this enzyme gave rise to multiple bands in mouse submandibular glands, suggesting that PRECE is a member of a protease family. Partial amino acid sequence analysis of purified PRECE and cloning and sequence analyses of its cDNA indicated that it is identical to the mGK-13 gene product, epidermal growth factor-binding protein type B, which is a member of the glandular kallikrein family and is involved in maturation of epidermal growth factor. Conditioned medium from Chinese hamster ovary cells transfected with an expression plasmid for PRECE had prorenin converting activity. These results indicate that PRECE is involved in the maturation of two bioactive polypeptides expressed in mouse submandibular glands, Ren-2 renin and epidermal growth factor.

Thyrotropin receptor non-mediated thyroid stimulating immunoglobulin in Graves' disease

There exists a consensus that hyperthyroid Graves' disease is caused by thyrotropin receptor (TSH-R) autoantibodies. To test the possibility that the TSH-R is the sole antigen for thyroid stimulating antibodies (TSAb), we compared bioactivities of Graves' IgGs between non-thyroid mammalian cells transfected with human TSH-R cDNA and the reference thyroid bioassay. A Graves' IgG with TSH-binding inhibitor immunoglobulin (TBII) activity (89%) markedly stimulated cAMP formation in both CHO-K1 cells transfected with TSH-R cDNA (340 microU/ml of TSH equivalent) and rat thyroid cells, FRTL-5, (410 microU/ml of TSH equivalent). In contrast, a TBII negative (-1.5%) IgG from another patient with Graves' disease showed a strong thyroid stimulating activity (87 microU/ml of TSH equivalent) when FRTL-5 cells were used for the assay. But no stimulating activity was observed in this IgG when CHO-K1 cells transfected with TSH-R cDNA were used, suggesting a possible existence of TSH-R non-mediated thyroid stimulating immunoglobulin in some cases of Graves' disease.

Carbachol-activated muscarinic (M1 and M3) receptors transfected into Chinese hamster ovary cells inhibit trafficking of endosomes

We examined the effects of isoproterenol and carbachol on fluid-phase endocytosis by Chinese hamster ovary (CHO) cells transfected with beta-adrenergic, M1, or M3 cholinergic receptors. Isoproterenol increased cAMP production and carbachol increased intracellular Ca, indicating successful expression of the receptor genes and coupling to typical signal transduction pathways. Carbachol inhibited the uptake of horseradish peroxidase (HRP) or Lucifer yellow (markers of fluid-phase endocytosis) in both M1- and M3-containing cells but not in wild-type cells, whereas isoproterenol did not affect pinocytosis in cells transfected with beta-adrenergic receptors. Carbachol inhibited the transit of HRP from an exchangeable pool to a nonexchangeable pool by a latent process requiring minimally 5 min of incubation. During the latent period, only one peak of low-density HRP-containing vesicles was found on Percoll gradients; after 5 min, HRP appeared in both high- and low-density vesicles. Carbachol-treated cells contained less HRP in the high-density fraction enriched in lysosomal markers. Early endosomes from CHO cells labeled for 5 min with HRP underwent fusion to make a more dense population of vesicles in the presence of ATP and KCl at 37 degrees C but not at 4 degrees C. The fused material contained increased levels of G proteins as detected either by ADP ribosylation with appropriate toxins or by immunoblotting with specific antibodies. These findings suggest that GTP binding proteins are internalized in endocytic vesicles and enter into a complex trafficking process involving fusion with other vesicular compartments. Trafficking of endosomes to these compartments is inhibited by activated M1 and M3 muscarinic receptors in CHO cells.

[Retropharyngeal hematoma following a bruise of head and neck--a case report and review of literature]

Diseases affecting the retropharyngeal space are relatively uncommon, much less a case of retropharyngeal hematoma. However, a space-occupying lesion in this area can be life threatening and require emergency surgical intervention. There have been 46 cases of retropharyngeal hematoma reported in the English literatures from 1934 to 1989, but there has been no reported case in Japan. Recently we treated a 72-year-old male sustained retropharyngeal hematoma following a bruise of head and neck. The patients was received tracheostomy, antibiotic therapy and intravenous hyperalimentation, and this hematoma was resolved in about 2 weeks. The etiologies, diagnosis, therapies in our case and prognoses of the literature reviewed 47 cases of retropharyngeal hematoma were discussed comprehensively.

[Elimination of PCDF and PCB congeners in the blood of patients with PCB poisoning in Taiwan]

The blood of 3 Yu-cheng patients sampled from 1980 to 1989 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. The high concentrations of 2,3,4,7,8-penta-, 1,2,3,4,7,8-hexa- and 1,2,3,4,6,7,8-hepta-CDFs (15.4, 37.7 and 4.8 ppb in lipid basis, respectively) were eliminated from the blood at half-lives of 2.14, 2.56 and 2.32 years, respectively. The high concentrations of 8 PCB congeners in the blood were also decreased with time at half-lives of 1.16-4.56 years. The half-lives of retainable PCB congeners were about 2 times longer than those of the PCDF congeners.

Two immunologically different isozymes of ascorbate peroxidase from spinach leaves

Two isozymes of ascorbate peroxidase (AP) from spinach leaves were separated by hydrophobic chromatography and designated AP-I and AP-II. They had similar molecular weights of about 31,000, as determined by gel-filtration, and showed high specificity for ascorbate. One of the two isozymes (AP-II) was purified to homogeneity by SDS-PAGE. Immunoblotting confirmed that antiserum against AP-II reacted with AP-II but not with AP-I. This antiserum inhibited the activity of AP-II, but not that of AP-I. The amino acid composition and partial amino acid sequence of AP-II were determined.

[PCB methyl sulphone: comparison of tissue levels in Baltic grey seals and a Yusho patient]

Methyl sulphone metabolites of PCB and DDE were isolated from different tissues of a Baltic grey seal (Halichoerus grypus). Main components in the seal blubber were identified as 3-MeSO2-2,2',4',5,5'-pentaCB, 4-MeSO2-2,2',4',5,5'-pentaCB, 3-MeSO2-p,p'-DDE, 4-MeSO2-2,2',3',4',5-pentaCB and 4-MeSO2-2,2',3,4',5',6-hexaCB. Liver and lung in the seal contained different MeSO2-PCB pattern compared to all other tissues. These levels in the both tissues were estimated to be 28 and 15 ppm (lipid basis) which corresponded to the same level as the PCB. Concentrations of MeSO2-PCB in any tissues of a Yusho patient were low compared to those in the seal.

Effects of 3-methylsulphonyl-4,5,3',4'-tetrachlorobiphenyl and 7,8-benzoflavone on aryl hydrocarbon hydroxylase activity in Ah responsive and Ah nonresponsive strains of mice

In general, C57BL/6NQdj (C57) and DBA/2JCrj (DBA) strains of mice are considered to be the aryl hydrocarbon (Ah) responsive and Ah nonresponsive strains of mice, respectively, which are determined by whether the hepatic aryl hydrocarbon hydroxylase (AHH) activity is enhanced (Ah responsive) or not (Ah nonresponsive) after the treatment of 3-methylcholanthrene (MC). In this study, first, we examined that the Ah responsiveness was systemically regulated in the lungs and kidneys as well as in the liver and observed its systemic control in these three organs in the two strains of mice. Then, we prepared the hepatic microsomes of the two strains of mice after the treatment of MC (42 mg/kg, once), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, 20 micrograms/kg, 6 times) and 2,3,4,7,8-pentachlorodibenzofuran (PenCDF 60 micrograms/kg, 6 times) in order to investigate the effects of 3-methylsulphonyl-4,5,3',4'-tetrachlorobiphenyl (3-MSF-TCB, 1.5-45 micrograms/ml) and 7,8-benzoflavone (ANF, 1.4-42 micrograms/ml) on the respective hepatic microsomal AHH activities and the following results were obtained. 1. As compared with the control enzyme activity, TCDD-induced AHH activity was the highest, PenCDF-induced one the second and MC-induced the lowest in both strains of mice. The inductions of the enzyme activity by these chemicals were much more remarkable in the Ah responsive C57 strain than those in the Ah nonresponsive DBA strain. 2. 3-MSF-TCB and ANF enhanced or reduced the enzyme activity depending on both their concentrations and kinds of microsomes, namely, those prepared from untreated control mice and mice treated with MC, TCDD or PenCDF.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation and characterization of recombinant human prorenin in Chinese hamster ovary cells

Recombinant human prorenin (rh-prorenin) was purified from supernatants of Chinese hamster ovary (CHO) cell line transfected with the cDNA for rh-prorenin by employing a simple two-step procedure which consisted of ammonium sulfate precipitation and immunoaffinity chromatography using a monoclonal antibody specific for the profragment of human prorenin. About 100-fold purification with 35% recovery was achieved after the two steps. Purified rh-prorenin migrated as a single protein band with apparent molecular weights of 46,000-47,000 and about 50,000 on SDS-PAGE and gel filtration (HPLC), respectively, although it consisted of multiple components (pI values, 5.6-6.4) that could be resolved by isoelectric focusing (IEF). The treatment of rh-prorenin with endo-beta-N-acetylglucosaminidase converted the rather broad protein band to a sharp band on SDS-PAGE and reduced the number of multiple pI peaks on IEF. Amino-terminal sequence analysis of both the purified rh-prorenin and rh-renin revealed Leu-Pro-Thr-Asp- and Leu-Thr-Leu-Gly-, respectively, which agreed with those predicted from the base sequences of their cDNA. These data suggested that microheterogeneity of rh-prorenin is due to the carbohydrate moiety, but not to the protein moiety. Purified rh-prorenin was almost inactive, but was cleaved at the carboxyl end of a dibasic pair Lys-2-Arg-1 by trypsin and converted to active renin. However, at the early stage during trypsin activation, new intermediate forms between rh-prorenin and rh-renin were formed, suggesting multiple activation steps of rh-prorenin in addition to the one step activation.

[A study for non-asbestos casting liners. An experimental study of the adaptability of MOD casting to die]

Asbestos liners for investment metal casting has frequently been used in dental laboratory work. In recent years, the dangerous properties of asbestos to the human body were reported in Europe and the United States, and casting liners without asbestos were developed and marketed by many manufacturers. These are so-called non-asbestos liners. This study evaluated the adaptability of MOD inlay castings to dies using 8 kinds of commercial non-asbestos liners of ADA standard No. 2 specifications. The results were as follows; Single and double layers of Casting ribbon, New Asbestos Ribon, Shofu experimental, and KAOLIN showed good adaptation. Shofu experimental with a single layer showed the best marginal adaptation (10 microns). OVAL LINERS and CASTING LINERS with single layer showed good adaptation, but with double layers the adaptation was poor. In FLASK LINER, the double layer showed better adaptation than that with a single layer. Most non-asbestos liners used in this study are adequate in useful to MOD inlay castings.

Aryl hydrocarbon hydroxylase activity levels in the hepatic microsomal fraction from MC- or TCDD-treated mice: a comparison between aromatic hydrocarbon responsive and non-responsive strains

The effects of in vivo administration of polycyclic aromatic hydrocarbons on the levels of aryl hydrocarbon hydroxylase (AHH) activity in aromatic hydrocarbon (Ah) responsive and non-responsive strains of mice were studied using the hepatic microsomal fraction. Injection of 3-methylcholanthrene (MC; 42 mg/kg body wt.) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 120 micrograms/kg body wt.) into both strains produced marked enhancement of AHH activity except for MC treatment of Ah non-responsive strains. Addition of 7,8-benzoflavone (BNF) to the microsomal AHH assay mixture prepared from mice previously injected with vehicle (olive oil) alone caused an increase in activity when the mice were responsive, while BNF lowered the activity in non-responsive strains. With regard to MC-injected mice, BNF and 3-methyl-sulphonyl-4,5,3',4'-tetrachlorobiphenyl (3-MSF-TCB) decreased microsomal AHH activity in Ah-responsive mice, whereas these drugs enhanced the activity in Ah-non-responsive strains. 3-MSF-TCB also had inhibitory potency on AHH activity, but the mechanism of inhibition seems to be somewhat different from that of BNF. It may also suggest that cytochrome P-450 isozymes inhibited by BNF are different from those inhibited by 3-MSF-TCB.

[Statistical studies of student clinical practice. 1. Clinical practice of operative dentistry from 1983 to 1989]

Clinical practice has been assigned as a final and very important aspect of study and practice of dental education. In our university, the students are exposed the clinical practice from the latter term of fifth year. This report investigated the protocols of clinical cases from the first to the seventh class of graduates. The results obtained were as follows: 1) The graduates of first class averaged 9 clinical cases. This decreased with the years and the fourth class averaged 5.5 cases. From the sixth class simulator training and mutual practice among the students was introduced and the total average of seventh class was 5.1 cases. 2) The dental practice centers on restoration and 20 percent of all cases were amalgam fillings from the first to four the class. However this decreased from the fifth class and does not take place at present. Composite resin restorations increased. Cast restorations occupied 20 percent of all cases and the proportion hasn't changed. 3) Clinical cases of graduates of fifth class who were first to include treatment between students averaged 7 cases. Mutual treatment practice is useful because of the increase exposure to clinical practice.

[Sensorineural hearing loss following the decompression of the facial nerve]

This study aims to ascertain whether sensorineural hearing loss occurs after the decompression of the facial nerve. Nine patients have undergone decompression of the facial nerve (limited to the vertical segment) by the transmastoid approach were selected as the subjects of this study because the influence of disinfectants and surgical trauma on the inner ear seems to be less severe in this operation than in tympanoplasty. Additionally, this approach seems to be more suitable for judgement of the effect of the drilling noise induced acoustic trauma on the inner ear than tympanoplasty. Though high tone abrupt sensorineural hearing loss was occurred in the operated ear in seven patients, no changes in hearing level were found in the contralateral side ear. Bekesy audiometry performed in only one case revealed Jerger II which suggested some disorder in the cochlea. Not only acoustic trauma induced by the drilling noise but also labyrinthitis occurred via the opened facial canal and the internal ear canal seemed to be the cause of sensorineural hearing loss following the decompression of the facial nerve.

In vitro effects of methylsulfonyl polychlorinated biphenyls and 7,8-benzoflavone on aryl hydrocarbon hydroxylase activity in human lymphoblastoid cells

The effects of 11 isomers of methylsulfonyl polychlorinated biphenyls (MSF-PCBs) on the aryl hydrocarbon hydroxylase (AHH) activity were examined at a fixed dose of 1.5 micrograms/ml by using cultured lymphoblastoid cells. One of the isomers 3-MSF-3',4,4',5-tetraCB, as well as 4-MSF-3,3',4',5-tetraCB and 4-MSF-3,3',4',5,5'-pentaCB, effectively reduced the AHH activity when added to the culture medium, especially that previously treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to induce the AHH activity. However, the inhibitory potencies exerted by the above three MSF-PCB compounds were smaller than that by 7,8-benzoflavone (BNF). When added to the culture medium simultaneously with TCDD or 3-methylcholanthrene (MC), 3-MSF-3',4,4',5-tetraCB blocked the enhancement of the AHH activity by TCDD but did not that by MC. This is in contrast to BNF which blocked the increases due to both TCDD and MC. On the other hand, 3-MSF-3',4,4',5-tetraCB added directly to the reaction mixture for the TCDD-induced AHH activity showed little influence, while BNF decreased the same activity. These results imply that the effect of 3-MSF-3',4,4',5-tetraCB on the AHH activity is different from that of BNF.

Isoproterenol stimulates shift of G proteins from plasma membrane to pinocytotic vesicles in rat adipocytes: a possible means of signal dissemination

Guanine nucleotide-binding regulatory proteins (G proteins) are linked to a large number of surface membrane receptors and appear to regulate a variety of effector systems located both in the plasma membrane and in other parts of the cell. The mechanism of the disseminative actions of G proteins remains obscure. During an investigation of the fate of two types of G proteins, Gs and Gi, in rat adipocytes, we unexpectedly found that isoproterenol, which stimulates cAMP levels and lipolysis in these cells, induces parallel increases in both Gs and Gi in a low-density microsomal fraction rich in endosomes and Golgi bodies. Two plasma membrane constitutive enzymes, adenylyl cyclase and 5'-nucleotidase, are also elevated in this fraction. NaF and NaN3, metabolic inhibitors, block the redistribution process. The isoproterenol-stimulated shifts are completely reversible after removal of the hormone, indicating a recycling, endocytic process. The endocytic process seems to be fluid phase endocytosis, or pinocytosis, since isoproterenol stimulates the uptake of both fluorescent-labeled dextran and horseradish peroxidase into the same vesicles containing Gs. However, the vesicles that accumulate in response to isoproterenol seem heterogenous in properties that may reflect the lipolytic process induced by isoproterenol. It is speculated that the "pinosomes" formed in response to lipolytic hormones may continually produce signals within the cellular interior during their processing and cycling. Hence, signal production in response to hormones need not be confined to the cell membrane; circulating pinosomes may be responsible for some of the disseminative effects of hormones.

[Experimental study on the air streams in the paranasal sinus]

Air streams in the paranasal sinus were investigated using Nose-Sinus Model to contribute to the fundamental knowledge of aerosol therapy. The results obtained were as follows; 1. The velocity of air streams in the paranasal sinus was measured by Laser Doppler Anemometer and the visualization of streams was done by Laser Light Sheet method. 2. The amount of aerosol passed into the maxillary sinus is approximately in proportion to the sectional area of the ostium. 3. A considerable amount of aerosol passing into the sinus was noted under LLS technique applying positive pressure from the choana. From the above results, it is necessary for the effective entrance of aerosol into the sinus first to open the middle meatus wide and to add the intermittent pressure.

[Simulation with a pre-clinical training system. 1. Practice in operative dentistry using an experimental manequin articulator, jaw model, and artificial teeth]

Clinical practice with patients is the most important part of education for dental students. However there are considerable difference between lecture, basic practice, and clinical practice. Therefore it is difficult to go from basic practice to clinical practice. To overcome this, we developed and introduced a Pre-Clinical Training system using a newly designed manequin, articulater, jaw model, and artificial teeth. This manequin is very similar to patients in appearance. The mandibular part used a semi-adjustable arcon type articulator. The artificial teeth were made of two types of synthetic resins with different hardness for use in operative dentistry. The teeth also have caries areas made of soft black resin. Using this system, the students practiced oral examination, cavity preparation and restoration in operative dentistry.

[The effectiveness of GaA1As semiconductor laser treatment to pain decrease after irradiation]

Recently, sedative and antiphlogistic treatment is conducted with low energy laser irradiation. The purpose of the this study was to evaluate the effectiveness to decrease of pain just after irradiation by a GaA1As semiconductor laser. The irradiation apparatus was SEMI LASER NANOX (LX-800: G-C. Co.) with the following features: a wave length of (around) 780nm: the laser energy, 30mW; exposure time, 30sec to 180sec/per treatment. Diagnosis of pre- and post-operative sensitivity were classified into the following four grades: Grade 0 no pain. Grade I mild pain. Grade II strong but tolerable pain. Grade III intolerable pain (simultaneous with stimulation). The results were as follows: 1. In the hypersensitivity of dentin, the treatment was not effective with 2 cases of grade III, but with all of grade I, II (35 cases) the pain decreased just after irradiation. 2. It was effective in all cases with pain like periodontitis after root canal filling and pain after extraction of teeth. 3. It was effective in all cases with gingivitis, stomatitis, and gingival ulcers after infiltration anesthesia etc..

[Simulation with a pre-clinical training system. 2. Evaluation of the pre-clinical training system]

This study evaluated usefulness of the Pre-Clinical Training System. Undergraduate students and instructors at Higashi-Nippon-Gakuen University practiced class I composite resin restoration of the lower right first molar using the system. After the practice, they filled out questionnaires to evaluate the system. According to the results, this system proved useful for pre-clinical education though there is room for improvement.