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Biomedical subjects

H Nishimura

Publications and source records attributed to H Nishimura.

At least 649 records · Page 36Linked to original sources
PubMed1988

A new trisaccharide sugar chain linked to a serine residue in bovine blood coagulation factors VII and IX.

A new trisaccharide sugar chain was identified in bovine blood coagulation factors VII and IX. A pentapeptide isolated from factor VII contained Ser-52, which could not be identified with a gas-phase sequencer, suggesting an unknown substituent on the serine residue (Takeya, H. et al. (1988) J. Biol. Chem., in press). The same results were obtained for a pentapeptide containing Ser-53 of factor IX. Component sugar analysis revealed that the peptide contained 1 mol of glucose and 2 mol of xylose. This sugar component was also confirmed by high-resolution fast atom bombardment mass spectrometric analysis of the pentapeptide. The trisaccharide was released from the peptides by means of beta-elimination reaction and its reducing end was coupled with 2-aminopyridine. The fluorescent pyridylamino (PA-) derivative of the trisaccharide was purified by gel-filtration and reversed-phase HPLC. The sugar composition of the PA-trisaccharide was found to be 2 mol of xylose and 1 mol of PA-glucose. These results indicate the existence of a (Xyl2)Glc-Ser structure in factors VII and IX.

Amino Acids↗
PubMed1988

Attachment of influenza C virus to human erythrocytes.

Binding experiments with radioactively labelled influenza C virions were carried out to investigate the interaction of the virus with human erythrocytes. The erythrocytes from any of 35 different individuals were found to contain influenza C virus-binding sites though their number was variable among the individuals and was much less than that on mouse, rat and chicken erythrocytes. Attachment of influenza C virus to human erythrocytes was inhibited completely by prior treatment of the virus with anti-HE monoclonal antibody having a strong haemagglutination inhibition activity. Pretreatment of erythrocytes with neuraminidase or the neuraminate-O-acetylesterase of influenza C virus resulted in a marked reduction in the level of virus binding. Thus it appears that human erythrocytes have a low level of O-acetylated sialic acid-containing glycoconjugates that can interact specifically with the HE glycoprotein of influenza C virus. Proteolytic digestion of erythrocytes with ficin, bromelain or V-8 protease inhibited virus binding almost completely, suggesting that the erythrocyte receptor for influenza C virus is a glycoprotein. In contrast to these enzymes, trypsin treatment of erythrocytes reduced virus binding by only about 50%, and alpha-chymotrypsin treatment did not inhibit at all. It was also found that treatment of erythrocytes with monoclonal antibody to the M or N blood group antigen greatly inhibited virus binding to the cells. These results, taken together, suggest that most influenza C virus receptors on human erythrocytes, if not all, reside on glycophorin A which is known to possess the M or N blood group activity.

Animals↗
PubMed1988

Operational and topological analyses of antigenic sites on influenza C virus glycoprotein and their dependence on glycosylation.

In our previous study, seven monoclonal antibodies specific for influenza C virus glycoprotein (gp88) were prepared and tentatively classified into two groups: group A (J14, J9, Q5, K16) has neutralization activity whereas group B (S16, J6, J15) does not. These antibodies were used to analyse the antigenic structure of gp88 and to examine the effect of glycosylation on the antigenicity of the glycoprotein. Operational analysis with a panel of antigenic variants selected with each of the group A antibodies identified two non-overlapping antigenic sites on the gp88 molecules, site A-1 recognized by J14, J9 and Q5 and site A-2 by K16. Sites A-1 and A-2 were shown, however, to be topographically overlapping by competitive binding assays. Competitive binding analysis with group B antibodies identified two additional non-over-lapping antigenic sites, site B-1 recognized by S16 and site B-2 by J6 and J15. It was found in radioimmunoprecipitation experiments that antibodies to sites B-1 and B-2 were reactive not only with gp88 but with its non-glycosylated form (T76) synthesized in the presence of tunicamycin. Antibodies to sites A-1 and A-2, in contrast, immunoprecipitated the T76 polypeptide in only trace amounts or not at all. Additionally, Western blot analysis showed that denatured gp88 blotted on nitrocellulose was reactive with antibodies to sites B-1 and B-2 but not with those to sites A-1 and A-2. These observations suggest that glycosylation of gp88 selectively influences the integrity of antigenic sites A-1 and A-2 which are composed of conformation-dependent epitopes.

Antibodies, Monoclonal↗
PubMed1988

Dephosphorylation of microtubule proteins by brain protein phosphatases 1 and 2A, and its effect on microtubule assembly.

Protein phosphatase C was purified 140-fold from bovine brain with 8% yield using histone H1 phosphorylated by the catalytic subunit of cyclic AMP-dependent protein kinase (cyclic AMP-kinase). Brain protein phosphatase C was considered to consist of 10 and 90%, respectively, of the catalytic subunits of protein phosphatases 1 and 2A on the basis of the effects of ATP and inhibitor-2. Protein phosphatase C dephosphorylated microtubule-associated protein 2 (MAP2), tau factor, and tubulin phosphorylated by a multifunctional Ca2+/calmodulin-dependent protein kinase (calmodulin-kinase) and the catalytic subunit of cyclic AMP-kinase. The properties of dephosphorylation of MAP2, tau factor, and tubulin were compared. The Km values were in the ranges of 1.6-2.7 microM for MAP2 and tau factor. The Km value for tubulin decreased from 25 to 10-12.5 microM in the presence of 1.0 mM Mn2+. No difference in kinetic properties of dephosphorylation was observed between the substrates phosphorylated by the two kinases. Protein phosphatase C did not dephosphorylate the native tubulin, but universally dephosphorylated tubulin phosphorylated by the two kinases. The holoenzyme of protein phosphatase 2A from porcine brain could also dephosphorylate MAP2, tau factor, and tubulin phosphorylated by the two kinases. The phosphorylation of MAP2 and tau factor by calmodulin-kinase separately induced the inhibition of microtubule assembly, and the dephosphorylation by protein phosphatase C removed its inhibitory effect. These data suggest that brain protein phosphatases 1 and 2A are involved in the switch-off mechanism of both Ca2+/calmodulin-dependent and cyclic AMP-dependent regulation of microtubule formation.

Animals↗
PubMed1988

Ampicillin concentrations in human dental granuloma after a single oral administration of talampicillin.

Ampicillin concentrations in human serum and dental granulomas of 31 patients were determined after a single oral dose of talampicillin (equivalent to 500 mg of ampicillin) was administered to each. The specimens were taken at 1.5, 2.0, 2.5, 3.0, and 3.5 h after the administration of talampicillin. The mean peak ampicillin concentrations in serum and dental granulomas occurred at identical times, 2.5 h, and were 8.29 micrograms/ml (range, 1.81 to 13.20 micrograms/ml) and 2.94 micrograms/g (range, 1.14 to 7.16 micrograms/g), respectively. The mean dental granuloma/serum ampicillin concentration ratio at the peak time (2.5 h) was 0.42 (range, 0.29 to 0.56). Ampicillin concentrations in dental granulomas exceeded most of the MICs for the bacteria commonly isolated from odontogenic infection.

Administration, Oral↗
PubMed1988

Change of insulin action with aging in conscious rats determined by euglycemic clamp.

To clarify the mechanism responsible for age-related changes in insulin action, the euglycemic clamp technique was performed with graded doses of insulin in conscious rats aged 2, 4, 10, and 20 mo. Insulin binding (IB) to muscle membranes was also studied. Maximal response of insulin-induced glucose disappearance rate (Rd) was decreased significantly between 2 and 4 mo of age. Dose-response curves shifted to the right progressively up to 20 mo of age. However, IB to the muscle membrane diminished between 1 and 4 mo of age without a decrease thereafter. When Rd was plotted against insulin bound to the membranes, the resulting curves shifted to the right with aging, suggesting a coupling defect between the binding and effector unit. In conclusion, insulin action alters in rats between 2 and 20 mo of age. The most pronounced impairment in IB and maximal response of insulin-induced Rd occurs during early life stage (through maturation) and then a coupling defect seems to be superimposed with further aging. However, we cannot exclude the possibility that these changes may be secondary to obesity or reduced physical activity, rather than aging per se.

Aging↗
PubMed1988

Angiotensin II-induced relaxation of fowl aorta.

Angiotensin II (ANG II) decreases blood pressure of fowl. To characterize the vasodilating action of ANG II and its underlying mechanisms, we examined the effect of [Asp1, Val5]ANG II (fowl ANG II) on isometric tension of fowl aortic rings. [Val5]ANG II (10(-8) to 10(-5) M) produced rapid, reversible, dose-dependent relaxation of aortas precontracted with phenylephrine. [Sar1,Ile8]ANG II blocked ANG II-induced relaxation; propranolol, atropine, methysergid, pyrilamine, and cimetidine did not. Endothelium removal abolished relaxation responses to ANG II and acetylcholine but not to isoproterenol or sodium nitroprusside. Inhibitors of phospholipase or arachidonic acid metabolism (quinacrine, indomethacin, 5,8,11,14-eicosatetraenoic acid, hydroquinone, metyrapone, SKF 525A) and a calcium channel blocker (verapamil) did not inhibit ANG II-induced relaxation, whereas indomethacin nearly completely blocked arachidonic acid-induced dilation of aortas with or without endothelia. Guanosine 3',5'-cyclic monophosphate (cGMP) levels in the aorta increased 15 s after ANG II application. Aortic relaxation was caused by 8-bromo-cGMP with or without intact endothelium. These results suggest that ANG II-induced relaxation of fowl aortas involves 1) an endothelium-dependent mechanism and 2) cGMP but not arachidonic acid metabolites.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1988

Genetic polymorphisms of orosomucoid and alpha-2-HS-glycoprotein in a Philippine population.

A Philippine population was investigated for genetic polymorphism of orosomucoid 1 (ORM1), orosomucoid 2 (ORM2), and alpha-2-HS-glycoprotein (A2HS) by isoelectric focusing. The allele frequencies were: ORM1*1 = 0.7904, ORM1*2 = 0.1687, ORM1*2.1 = 0.0409, ORM2*1 = 1.0000; A2HS*1 = 0.6870, A2HS*2 = 0.3130. Compared with the Japanese population, the Philippine population has higher frequencies of ORM1*1 and A2HS*2, and lower frequencies of ORM1*2.1 and A2HS*1.

Alleles↗
PubMed1988

Reliability of percutaneous test for facial nerve function. Comparison between indirect and direct stimulation method.

To evaluate the reliability of conventional tests for facial nerve denervation, comparisons of the thresholds and relationship with prognosis were made between the conventional percutaneous and direct stimulation methods in 11 cases of facial palsy decompressed and followed up for more than 6 months. Although all cases showed complete or severe nerve degeneration in the preoperative percutaneous stimulation test, the threshold for the direct intraoperative stimulation test varied from 4 V (normal) to more than 30 V. The results of the direct intraoperative stimulation test correlated well with prognosis (degree of improvement of palsy score). Our results indicate that the direct stimulation method is better than the percutaneous stimulation method as an electrodiagnostic test for nerve degeneration.

Adolescent↗
PubMed1988

Defective processing of insulin-receptor precursor in cultured lymphocytes from a patient with extreme insulin resistance.

We have studied a patient with extreme insulin resistance, acanthosis nigricans, and decreased erythrocyte insulin binding. EBV-transformed lymphocytes from this patient exhibited markedly reduced binding of 125I-insulin. Radioiodination of cell surface receptors followed by immunoprecipitation with anti-receptor antibodies revealed the presence of increased amounts of a 210-kD protein but no detectable alpha or beta subunits. Continuous labeling with 2-[3H]mannose revealed the synthesis of a 190-kD precursor and a 210-kD protein. The 210-kD protein was phosphorylated in an insulin-dependent manner at high insulin concentrations. These results suggest that in this patient the biosynthesis of 190-kD receptor precursor, its terminal glycosylation, and intracellular transport to the cell surface proceed normally, while proteolytic maturation to alpha and beta subunits does not occur. We postulate that this defect either results from mutation(s) within the insulin-receptor gene, which render the precursor resistant to cleavage, or from a defect in the receptor processing enzyme.

Acanthosis Nigricans↗
PubMed1988

Insulin resistance in a boy with congenital generalized lipodystrophy.

We have studied insulin resistance in a 12-year-old Japanese boy who presented with congenital generalized lipodystrophy. Oral glucose tolerance test exhibited a diabetic pattern with normal fasting plasma glucose. Results from euglycemic glucose clamp study showed decreases in both insulin sensitivity and responsiveness. Both the patient's erythrocytes and Epstein-Barr virus transformed lymphocytes showed low-normal insulin binding with a slight reduction in binding affinity in the latter. Insulin binding to the cultured fibroblasts was decreased due to a lowered affinity. In addition, they displayed a rightward shift of the insulin dose-response curve for D-14C-glucose uptake with no decrease in the maximum uptake. Insulin-stimulated autophosphorylation and kinase activity of the wheat germ agglutinin purified receptors from the Epstein-Barr virus-transformed lymphocytes appeared normal. The reason for some discrepancies in insulin binding among the cells remains unknown, and we cannot formulate a conclusion as to whether or not a primary binding defect of insulin receptors exists and contributes to insulin resistance in the patient. The decrease in insulin responsiveness demonstrated in the glucose clamp study may result from a defect at the rate-limiting step in the postbinding process of insulin action, presumably a defect in the glucose transport system in muscle tissues. The defect may be secondary to changes in in vivo circumstances.

Cell Line, Transformed↗
PubMed1988

Purification of the multifunctional calmodulin-dependent protein kinases from lung and liver, and the comparison to the brain enzyme.

We purified the multifunctional calmodulin-dependent protein kinases (calmodulin-kinase) from rat lung and rabbit liver, and compared the properties of this enzyme with those of the rat brain enzyme. The lung and liver enzymes had molecular weights (Mr's) of 530,000 and 330,000 with main subunits of 52 and 51 kDa, respectively. Although the lung and liver enzymes cross-reacted with antibodies to the brain enzyme, the immunoreactivity of the lung enzyme was weaker. The substrate specificity of the three enzymes showed differences in the relative reaction rate of phosphorylation. The patterns of phosphopeptides of the lung and liver enzymes were similar to each other and only partly common to that of the 60-kDa subunit of the brain enzyme.

Animals↗
PubMed1988

Regulation of glucose-transporter gene expression by insulin in cultured human fibroblasts.

To clarify the effect of insulin on glucose-transporter (GT) biosynthesis, we determined GT mRNA levels in human cultured skin fibroblasts, using HepG2 GT cDNA as a probe. Insulin specifically increased the GT mRNA level in a time- and dose-dependent manner. Time-course study demonstrated that the mRNA level peaked within 3 h of insulin (1 x 10(-7) M) addition. After remaining elevated for several hours, mRNA decreased and returned to the basal level after 24 h. In the cell strains from seven normal subjects, the mean (+/- SE) GT mRNA level determined after 3 h of treatment with 1 x 10(-7) M insulin was 164.3 +/- 8.5% of the level found in untreated control cells. The insulin dose-response curve of GT mRNA levels showed that the maximum stimulation was elicited at 1 x 10(-7) M, and the half-maximum stimulation occurred at approximately 5 x 10(-10) M. Degradation rates of GT mRNA determined in the presence of actinomycin D were not different between insulin-treated and untreated cells. These results suggest that insulin increases GT gene expression in cultured human fibroblasts.

Cells, Cultured↗
PubMed1988

Occurrence of sequelae in Bell's palsy.

The occurrence of sequelae in 330 patients with Bell's palsy followed up for more than 6 months was investigated. At least one of five kinds of sequelae (synkinesis, crocodile tears syndrome, spasm, contracture, tinnitus and/or hearing loss during facial movement) was observed in 30 of the 330 cases (9.1%). Sequelae occurred at 23.9-39.0 weeks (mean) after onset of palsy and at scores of 30-34 points (mean; full score 40 points). The incidence of sequelae was correlated to the degree of facial nerve dysfunction.

Facial Muscles↗
PubMed1988

Adult T-cell leukemia/lymphoma in pregnancy.

Adult T-cell leukemia/lymphoma, a lymphocytic leukemia caused by human T-cell lymphoma virus-I (HTLV-I), is prevalent in southwestern Japan. A Japanese woman with adult T-cell leukemia/lymphoma in the third trimester of pregnancy was delivered of an infant by cesarean section. She did not breast-feed the child, who has remained free from HTLV-I infection.

Adult↗
PubMed1988

[Phase II study of carboplatin in ovarian cancer].

A phase II study of carboplatin was conducted in ovarian cancer by a cooperative study group consisting of 22 institutions nationwide. The overall response rate of 50 evaluable cases was 38.0%. The response rate in cases with no prior chemotherapy was 54.2% and that with prior chemotherapy was 23.1%. In addition, the response rate was 26.3% in cases that received prior CDDP-based chemotherapy. Histologically, the response rate was high in serous cystadenocarcinoma and endometrioid adenocarcinoma. Hematologic toxicities, particularly leukopenia and thrombocytopenia, were frequently observed, but well tolerated, while renal and neurologic toxicities were rare. These results suggested that carboplatin is useful in the treatment of ovarian cancer.

Adenocarcinoma↗
PubMed1988

[Phase III study of carboplatin in ovarian cancer].

A phase III study of carboplatin vs cisplatin in CAP regimen for ovarian cancer was conducted by a cooperative study group consisting of 22 institutions nationwide. The response rate for 23 cases allocated to carboplatin regimen group was 34.8% and 42.1% for 19 cases allocated to cisplatin regimen group. No significant difference was observed between these two regimens in response rates, and no significant differences were noted between the two regimens in each of the clinical toxicities and abnormalities in laboratory findings. Since the carboplatin regimen group did not require hydration, or the use diuretics or antiemetics, these results suggested that carboplatin is more useful in the treatment of ovarian cancer than cisplatin.

Adult↗