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Biomedical subjects

N Kumagai

Publications and source records attributed to N Kumagai.

At least 19 recordsLinked to original sources
PubMed1992

A rho gene product in human blood platelets. II. Effects of the ADP-ribosylation by botulinum C3 ADP-ribosyltransferase on platelet aggregation.

In the accompanying paper (Nemoto, Y., Namba, T., Teru-uchi, T., Ushikubi, F., Morii, N., and Narumiya, S. (1992) J. Biol. Chem. 267, 20916-20920), we have identified rhoA protein as the sole substrate protein for botulinum C3 ADP-ribosyltransferase (C3 exoenzyme) in human blood platelets. Here we examined the role of rhoA protein in platelet functions. C3 exoenzyme added to washed platelets dose- and time-dependently ADP-ribosylated rhoA protein in situ in the cells. Concomitant with this modification, inhibition of thrombin-induced platelet aggregation was observed. This inhibition was not reversed by washing the treated platelets, but was not found when C3 exoenzyme was pretreated with mouse monoclonal anti-C3 exoenzyme antibody. C3 exoenzyme treatment did not affect thrombin-induced inositol 1,4,5-trisphosphate production. Secretion of preloaded [14C]serotonin was delayed by the enzyme treatment, but the extent of the secretion was not influenced. In addition, the enzyme treatment did not change the expression of the glycoprotein IIb-IIIa complex on the platelet surface. The enzyme treatment also suppressed platelet aggregation induced by phorbol myristate acetate. These results suggest that rhoA protein plays a role mainly in the aggregation process downstream from receptor-phospholipase C coupling. This, together with the previous finding that rhoA protein modulates stress fiber formation in cultured fibroblasts (Paterson, H. F., Self, A. J., Garrett, M. D., Just, I., Aktories, K., and Hall, A. (1990) J. Cell Biol. 111, 1001-1007), suggests that rhoA protein regulates the assembly of actin filaments and the avidity of the platelet integrin (glycoprotein IIb-IIIa) in the aggregation process.

ADP Ribose Transferases↗
PubMed1992

Continuous chitosan hydrolyzate production by immobilized chitosanolytic enzyme from Enterobacter sp. G-1.

Chitosanolytic enzymes from Enterobacter sp. G-1 were immobilized on various carriers to continuously hydrolyze chitosan. Four different carriers were tested: FE-3901 (strong basic anion exchange resin, ionic binding), glutaraldehyde-treated FE-4612 (weak basic anion exchange resin, cross-linking), Chitopearl (chitosan beads), and alginate calcium. Glutaraldehyde-treated FE-4612 and Chitopearl immobilized more protein than the others. The enzyme immobilized on FE-3901 had the greatest activity. The activity of enzyme immobilized on FE-3901 decreased rapidly when exposed to a continuous flow of 1% chitosan. The enzyme immobilized with Chitopearl retained more than 50% of its original activity after 17 days, and the activity was fully restored by re-immobilization.

Anion Exchange Resins↗
PubMed1991

Changes of lysosomal proteinase activities and their expression in rat cultured keratinocytes during differentiation.

The cathepsins B, H and L, lysosomal cysteine proteinases, play a major role in intracellular protein degradation. These proteinase activities and expressions were examined in a Ca2+ regulated epidermal culture system which consists of two morphological cell types: undifferentiated cells grown in low Ca2+ (0.1 mM concentration) and differentiated cells grown in high Ca2+ (1.8 mM concentration), respectively. Cathepsin B and L activities of the differentiated cells showed a several-fold increase compared to that of the undifferentiated cells. In addition, by using CM-cellulose column chromatography, cathepsin B and L were separated and the level of cathepsin L activity increased significantly. Cathepsin B, L and H were also detected by using an immunoblotting procedure in which their bands were expressed after differentiation was induced by the increasing calcium concentration. Cathepsin L activity and immunostaining intensity reached a maximum at 1 or 2 days of differentiation. In contrast, cystatin alpha (an endogenous inhibitor of cysteine-dependent cathepsins) appeared in the final stage of differentiation. These results indicate that the expression of epidermal cathepsins and their endogenous inhibitor are involved in part of the program of cell differentiation and the terminal differentiation process in cultured rat keratinocytes.

Animals↗
PubMed1991

Differentiating effect of sodium butyrate on human hepatoma cell lines PLC/PRF/5, HCC-M and HCC-T.

The in vitro effect of sodium butyrate (SB) on human hepatoma cell lines PLC/PRF/5, HCC-M and HCC-T was investigated. SB was added at the non-toxic but cytostatic concentration of 1 mM. In all these cell lines, SB reduced cell proliferation and changed the morphology of the cells into a fibroblast-like shape. In PLC/PRF/5, alpha-fetoprotein production and c-myc expression were inhibited. In contrast, gene expression of albumin, one of the normal liver-cell products, and that of integrated hepatitis B virus genome, was increased. In HCC-M and HCC-T, c-myc expression, which was enhanced in the naive state, was reduced. In HCC-M, fos expression was inhibited but the expression of N- and K-ras genes did not change. SB seemed to induce normal or mature properties of hepatocytes in human hepatoma cell lines.

Blotting, Northern↗
PubMed1991

Diagnostic reliability and significance of irregular beta patterns.

We designated EEGs with marked and irregular beta waves in basic patterns as "irregular beta patterns" on the basis that these patterns are related with particular symptoms such as dysphoria, irritability and autonomic symptoms and they implicate choice of therapeutic agents. Because of good response to antiepileptic agents in patients with "irregular beta patterns" along with EEG characteristics, we hypothesized that the prevalence of "irregular beta patterns" is higher in epileptics than in other psychiatric patients. In the present study, we tested this hypothesis, investigating actual frequencies of these patterns among different diagnostic categories for all patients whose EEG were recorded in all the first-visit patients to the Outpatient Clinic, Department of Neuropsychiatry of the Tokyo University Hospital during one year period of 1986. Before starting this investigation, we checked the interrater reliability for these patterns. Therefore, two studies are reported here. In Study 1, five raters judged 98 EEG recordings blindly (43 epileptics and 55 healthy subjects). As a result, the generalized Kappa of 0.473 was obtained, indicating our agreement level was moderate or fair. This result lends support to our contention that irregular beta patterns are reliably judged. In Study 2, we judged the EEG recordings (137 schizophrenics, 62 affective disorders, 43 epileptics and 55 healthy controls) and calculated the prevalence rate of "irregular beta patterns" among the diagnostic categories. The results show that the prevalence rates of "irregular beta patterns" among psychiatric disorders and normal controls were 13% (18/137) in schizophrenics, 11% (7/62) in affective disorders, 14% (6/43) in epileptics and 4% (2/55) in healthy controls. These rates did not differ significantly among the three disorders. Thus, our hypothesis was not supported. The clinical significance of these patterns is discussed.

Adult↗
PubMed1991

Monotherapy for childhood epilepsies with zonisamide.

Zonisamide was tried on 44 children, 18 girls and 26 boys, from 8 months to 15 years of age at the start of the trial. In 6 children the drug has been stopped because of side effects. The drug was introduced at a dose of 2-4 mg/kg/day and increased to 12 mg/kg/day unless a satisfactory response occurred at a lower dose. A 100% control of seizures was achieved in 5 of 5 cases of idiopathic generalized epilepsies, in 7 of 8 cases of symptomatic generalized epilepsies, in one of one case of idiopathic partial epilepsies, and in 17 of 24 cases of symptomatic partial epilepsies. The main side effect was drowsiness, especially during the introduction.

Administration, Oral↗
PubMed1991

Guanosine 5'-triphosphate converts some populations of propylbenzilylcholine mustard-sensitive muscarinic cholinoceptor sites to sites resistant to the drug in intestinal smooth muscle.

From functional studies with propylbenzilylcholine mustard (PrBCM), we reported that there coexist PrBCM-sensitive and PrBCM-resistant muscarinic cholinoceptor mechanisms in guinea pig taenia caecum. We investigated the interrelationship between these two cholinoceptor mechanisms using an in vitro receptor binding assay with [3H]quinuclidinyl benzilate (QNB) and [3H]PrBCM. Pretreatment of the muscle strips with 300 nM PrBCM (in vivo alkylation) for 10-50 min resulted in progressive decreases of the number of the maximum [3H]QNB binding sites. However, a prolongation of the period of in vivo alkylation up to 90 min was accompanied with no further loss in the binding sites. Under these conditions, there is no significant change in the affinity of [3H]QNB for the binding sites. The concentration of carbachol required to displace 50% of the bound [3H]QNB was larger in membranes obtained from the tissues that had been alkylated in vivo with PrBCM for 50 min than that from control strips, but was not altered when the pretreatment with the drug was carried out after homogenization (in vitro alkylation). When GTP was added during in vitro alkylation, the affinity of carbachol was lower than that in control membranes, as observed when in vivo alkylation was carried out. In the presence of guanine nucleotide, PrBCM thus appears to recognize two distinct populations or states of muscarinic receptors.

Alkylation↗
PubMed1991

Proto-oncogene expression in three human hepatoma cell lines, HCC-M, HCC-T and PLC/PRF/5.

Changes of nucleotide sequences and expressions of cellular oncogenes in human hepatoma cell lines, PLC/PRF/5, HCC-M and HCC-T cells, were examined by Southern and Northern blot analyses. The probes used are DNA fragment of myc, N-, H-, K-ras, fos, fms, raf, erb-A, erb-B, and erb-B2 genes and synthetic oligonucleotides corresponding to the part of N-, H-, K-ras genes. The results are as follows. DNA amplification and rearrangement were not detected in these three human hepatoma cell lines. Point mutations at codons 12, 13, and 61 in N- and K-ras genes were not demonstrated in these cell lines. N-, H-, K-ras and myc transcripts were detected in these three cell lines. However, fos gene transcript was detected only in PLC/PRF/5 and HCC-M cells which were derived from hepatitis B related hepatocellular carcinoma and having integrated hepatitis B virus (HBV) DNA. These data showed that there are no specific proto-oncogene expression into RNA except for myc and ras genes, nor DNA rearrangement in these 3 human hepatoma cell lines with regards to at least 10 different oncogenes examined and suggest the relationship between fos gene expression and integration of HBV DNA in host cell DNA.

Blotting, Northern↗
PubMed1991

Identification of colony-stimulating factor activity in patients with malignant tumors associated with excessive leukocytosis.

We have tried to demonstrate and identify colony-stimulating factor (CSF) activity in the plasma, pleural fluid, ascites or culture supernatant of tumor cells in 11 patients with malignant tumors associated with unexplained persistent leukocytosis. The specimens were treated with anti-granulocyte (G)-CSF or anti-granulocyte/macrophage (GM)-CSF monoclonal antibodies, then added to GM-progenitor (CFU-GM) cultures without exogenous CSFs. In all patients, untreated specimens generated CFU-GM-derived colonies, and colony formation was clearly inhibited by only one of the two antibodies, indicating the presence of either G-CSF or GM-CSF in the specimens. Furthermore, we measured the concentrations of G-CSF or GM-CSF in the specimens using an enzyme-linked immunosorbent assay, and confirmed the results by CFU-GM assay. Two patients were shown to have GM-CSF-producing tumors, while the other patients were G-CSF-producing. These assays are useful in identifying CSF activity in patients with CSF-producing tumors.

Aged↗
PubMed1991

[Abnormal vergence eye movement during eyelid closure caused by a pineal tumor].

A case with abnormal eye movement induced by eyelid closure and selective paralysis of downward gaze was reported. CT scan and MRI imaging revealed a pineal tumor with bilateral involvement of the thalamomesenchephalic junctions without obvious damage to the posterior commissure. Histopathologically, the tumor was a germinoma. The pupillary light reflex was absent and near reflex was reduced. Lightning eye movement, skew deviation and convergence-retraction nystagmus were observed. The horizontal eye movement was normal in both eyes. The eye did not move downward below the level of direct forward gaze spontaneously or on attempted downward gaze. Downward vestibulo-ocular reflex was absent. Bilateral abnormal vergence eye movement with alternating convergence and divergence was observed during eyelid closure. The cycle of the abnormal eye movement was about 3Hz and there was no fast phase. The abnormal eye movement was not observed in the darkened room with both eyes open. After subtotal removal and radiation therapy of the pineal tumor, the abnormal eye movement disappeared.

Adult↗
PubMed1990

Psychiatric patients showing irregular beta activities in EEGs and treatment with antiepileptic drugs: a report of 15 cases.

Fifteen psychiatric cases are reported who were clinically diagnosed as schizophrenic, affective disorders, or neurotic, but resisted standard medication regimens, all showing irregular beta activities on EEGs. The cases tended to display symptoms in common, such as dysphoria, emotional instability or frequent physical complaints. These characteristic symptoms share something mutually with the symptoms shown in some epileptic patients or psychiatric patients with epileptic EEG abnormalities without clinical seizures. Antiepileptic drugs seemed more specifically effective to the above symptoms. More than half of these cases showed improvement on EEG findings such as a decrease in irregular beta activities and an increase in rhythmicity or regularity of alpha activities along with clinical improvement with the administration of adjunctive antiepileptic drugs. These results suggest that the adjunctive administration of antiepileptic drugs to patients with irregular beta activities on EEGs is clinically useful and an EEG examination has much value in psychiatric practice to find the criteria of drug therapy.

Adult↗
PubMed1990

Expression of hepatitis B surface antigen in Chang cells transfected with hepatitis B virus DNA.

To investigate hepatitis B virus (HBV) biology in vitro, the transfection of recirculized HBV DNA into Chang cell line was performed. Linear HBV DNA was isolated from recombinant HBV DNA, pHBR105, which includes the whole genome of HBV and was recirculized. Chang cells were transfected with this recirculized HBV DNA by the two different procedures of calcium/phosphate coprecipitation and electroporation. After the transfection, the presence of large nucleated cells with multinuclei and ground-glass cytoplasma were noticed and these cells seemed to proliferate faster than untreated Chang cells. Transient expression of hepatitis B virus surface antigen (HBsAg) was demonstrated in cytoplasma of transfected cells by indirect immunofluorescence. HBsAg was not detected in the culture supernatants by radioimmunoassay. The extra-chromosomal HBV DNA was detected in the transfected cells by both procedures 7 weeks after the transfection by Southern blot analysis but it was lost 4 weeks after that. It was demonstrated that it was possible to transfect Chang cells with HBV DNA and that DNA was functioning to express HBsAg transiently.

Cell Line↗
PubMed1979

Cystic partially differentiated nephroblastoma and multilocular cyst of the kidney. Report of two cases of so-called multilocular cyst of the kidney.

Two cases of so-called multilocular cyst of the kidney are presented. Although both cases satisfied all of the criteria which characterize the multilocular cyst of the kidney, one had cystic lesions and neoplastic lesions (nephroblastoma-like lesions) and the other had only cystic lesions and was complicated with hamartoma. We prefer the term "cystic partially differentiated nephroblastoma" as the diagnostic term for the former and "multilocular cyst of the kidney" for the latter. A study of 40 reported cases of multilocular cystic lesions of the kidney revealed that cases having only cystic lesions were distributed in all ages from 4.5 months to 71 years and that cases having neoplastic lesions were seen in infants from 4 months to 2 years.

Adolescent↗
PubMed1979

Experimental cryptococcal myocarditis.

Rabbits and rats developed myocarditis on the 16th, 30th, and 60th day after intrarenal inoculation with Cryptococcus neoformans. The cardiac lesions consist of focal necrosis with infiltrations of small round cells in the myocardium. Cryptococcal antigens were demonstrated by a direct immunofluorescent antibody method in the damaged myocardial lesions. Cryptococcus neoformans itself was found by periodic acid-Schiff stain in the damaged myocardial lesions.

Animals↗
PubMed1978

Experimental Coxsackie virus B-3 and B-4 myocarditis in mice.

Mice were inoculated with recently isolated Coxsackie virus B-3 and B-4 intraperitoneally. Severest lesions in the hearts were observed in mice between the age of 7 and 14 days. Grossly yellow-white patches were seen on the hearts of mice from the 7th day to the 6th month after virus inoculation. Microscopically, the heart showed extensive myocardial necrosis, inflammation with small mononuclear cells and calcification on the day of 7. There were myocardial fibrosis and calcification at the 6th month after inoculation with Coxsackie virus B-3, and at the 3rd month after inoculation with Coxsackie virus B-4, but generally pathologic changes were less severe in the latter. Myocardial fibrosis in the present experiment was most prominent among the experiments we have studied. It was confirmed that chronic myocardial fibrosis follows acute Coxsackie virus myocarditis in mice. Possible role of Coxsackie virus myocarditis in the development of cardiomyopathy was briefly discussed.

Animals↗