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Biomedical subjects

S Nagayama

Publications and source records attributed to S Nagayama.

At least 37 records · Page 2Linked to original sources
PubMed1999

Developmental changes in distribution of death-associated protein kinase mRNAs.

Death-associated protein kinase (DAP-kinase) is Ca(2+)/calmodulin-dependent serine/threonine kinase that contains ankyrin repeats and the death domain. It has been isolated as a positive mediator of interferon-gamma-induced apoptotic cell death of HeLa cells. In order to reveal the physiological role of DAP-kinase, the tissue distribution and developmental changes in mRNA expression of DAP-kinase were investigated by Northern blot and in situ hybridization analyses. DAP-kinase mRNA was predominantly expressed in brain and lung. In brain, DAP-kinase mRNA had already appeared at embryonic day 13 (E13) and was, thereafter, detected throughout the entire embryonic period. High levels of expression were detected in proliferative and postmitotic regions within cerebral cortex, hippocampus, and cerebellar Purkinje cells. These findings suggest that DAP-kinase may play an important role in neurogenesis where a physiological type of cell death takes place. The overall expression of DAP-kinase mRNA in the brain gradually declined at postnatal stages, and the expression became restricted to hippocampus, in which different expression patterns were observed among rostral, central, and caudal coronal sections, suggesting that DAP-kinase may be implicated in some neuronal functions. Furthermore, it was found that the expression of DAP-kinase mRNA was increased prior to a certain cell death induced by transient forebrain ischemia, indicating a possible relationship between DAP-kinase and neuronal cell death.

Animals↗
PubMed1999

Multidrug resistance and the lung resistance-related protein in human colon carcinoma SW-620 cells.

BACKGROUND: Lung resistance-related protein (LRP), the major vault protein in humans, is sometimes overexpressed in multidrug-resistant cells. Because cells transfected with the LRP gene did not express the multidrug-resistant phenotype, we investigated whether LRP is involved in multidrug resistance. METHODS: SW-620 cells, a human colon carcinoma cell line, alone or transfected with an expression vector carrying a LRP-specific ribozyme or with an empty vector, were treated with sodium butyrate to induce differentiation. Expression of P-glycoprotein, multidrug resistance protein, and LRP in the cells was examined by northern and western blotting, and the efflux of doxorubicin in the cells or isolated nuclei was examined by fluorescence microscopy. RESULTS: A 2-week treatment with sodium butyrate induced LRP and conferred resistance to doxorubicin, vincristine, etoposide, gramicidin D, and paclitaxel (Taxol) in SW-620 cells. Insertion of either of two LRP-specific ribozymes into SW-620 cells inhibited these activities. Levels of drugs accumulating in the cells were not decreased by sodium butyrate, suggesting that the adenosine triphosphate-binding cassette transporter is not involved in sodium butyrate-induced multidrug resistance. Doxorubicin was mainly located in the nuclei of untreated cells and in the cytoplasm of sodium butyrate-treated cells. Isolated nuclei from untreated cells or sodium butyrate-treated cells incubated with anti-LRP polyclonal antibodies contained more doxorubicin than the nuclei of sodium butyrate-treated cells alone. Efflux of doxorubicin was greater from the nuclei of sodium butyrate-treated cells than the nuclei of untreated cells or of sodium butyrate-treated cells transfected with a LRP-specific ribozyme and was inhibited by an anti-LRP polyclonal antibody. CONCLUSIONS: LRP is involved in resistance to doxorubicin, vincristine, etoposide, paclitaxel, and gramicidin D and has an important role in the transport of doxorubicin from the nucleus to the cytoplasm.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Characterization of CFTR expression in a human pulmonary mucoepidermoid carcinoma cell line, NCI-H292 cells.

The NCI-H292 cell, a human pulmonary mucoepidermoid carcinoma cell line, is commonly used for studying bacterial and viral infections of airway epithelial cells. Dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) is the main cause of fetal lung infection in cystic fibrosis patients. In this study, we examined CFTR expression in NCI-H292 cells to determine whether NCI-H292 cells possess sufficient, normally functioning CFTR. The results of RT-PCR and Northern blotting analysis indicated that the CFTR gene expression level was much lower in NCI-H292 cells than in T84 cells. However, Western blotting analysis showed that protein expression in NCI-H292 cells was comparable to that in T84 cells. Furthermore, whole-cell and cell-attached patch clamp electrophysiological techniques indicated that the Cl- current induced by intracellular cAMP elevation in NCI-H292 cells was comparable to that in T84 cells. These findings suggest that NCI-H292 cells with a low level of CFTR gene expression possess enough functional CFTR to show a physiological response.

Base Sequence↗
PubMed1998

Increased sensitivity to vincristine of MDR cells by the leukotriene D4 receptor antagonist, ONO-1078.

The leukotriene D4 (LTD4) receptor antagonist, 4-oxo-8-[p-(4-phenylbutyloxy)benzoylamino]-2-(tetrazol-5-yl) -4H-1-benzopyran hemihydrate (ONO-1078) is used for the treatment of allergic asthma and other immediate hypersensitivity diseases. We examined the effect of ONO-1078 on the sensitivity to vincristine (VCR) of MRP overexpressing multidrug-resistant CV60 and its parental drug-sensitive KB-3-1 cell lines. The sensitivity to VCR of KB-3-1 and CV60 cells was increased 13- and 15-fold, respectively, by ONO-1078 at the maximum non-toxic concentration (100 microM). The VCR sensitivity of multidrug-resistant KB-C2 cells that overexpressed P-gp was increased 2.6-fold by ONO-1078. The accumulation of VCR in KB-3-1, CV60 and KB-C2 cells was significantly increased by ONO-1078. The efflux of VCR from KB-3-1 cells was not inhibited, but that from CV60 cells was enhanced compared with that from KB-3-1 cells and was partially inhibited by ONO-1078. ONO-1078 competitively inhibited the ATP-dependent [3H]LTC4 uptake in membrane vesicles isolated from CV60 cells. These findings suggest that ONO-1078 inhibits the transporting activity of MRP and that ONO-1078 increases the sensitivity to VCR of KB-3-1 cells by increasing the VCR uptake in the cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Suicidal inactivation of human dihydropyrimidine dehydrogenase by (E)-5-(2-bromovinyl)uracil derived from the antiviral, sorivudine.

An enzymatic study was performed to clarify the mechanism of 18 acute deaths in patients who had received the new oral antiviral drug, sorivudine (SRV), during anticancer chemotherapy with 5-fluorouracil (5-FU) prodrugs. Human dihydropyrimidine dehydrogenase (hDPD), playing a key role in the liver as the rate-limiting enzyme in catabolism of 5-FU, was expressed in E. coli, purified and incubated in the presence of NADPH with SRV or (E)-5-(2-bromovinyl)uracil (BVU), a metabolite of SRV produced by human gut flora. hDPD was rapidly and irreversibly inactivated by BVU, but not by SRV. Radioactivity of [14C]BVU was incorporated into hDPD in the presence of NADPH in a manner reciprocal to the enzyme inactivation. In the absence of NADPH, hDPD was not inactivated by BVU, nor radiolabeled with [14C]BVU. Thus, as we demonstrated previously with studies using the rat, the acute deaths were strongly suggested to be attributable to markedly elevated tissue 5-FU levels which were responsible for irreversible inhibition of hDPD by covalent binding of a reduced form of BVU as a suicide inactivator.

Antiviral Agents↗
PubMed1998

Inhibition of glycine-induced current by morphine in nucleus tractus solitarii neurones of guinea pigs.

We studied the effect of morphine on the current induced by glycine in acutely dissociated nucleus tractus solitarii (NTS) neurones of guinea pigs, by use of the whole-cell patch clamp technique. Morphine inhibited 30 microM glycine-induced current (Igly), without affecting the current caused by 30 microM GABA. The effect of morphine was concentration-dependent, with a maximal effect at 1 mM, and reversible. The half-maximum inhibitory concentration of morphine was 30 microM. The effect of morphine was not depressed by naloxone, an opioid antagonist. Furthermore, the effect was not substantially affected by methiothepin, a 5-HT1 antagonist, ketanserin, a 5-HT2 antagonist and MDL-72222, a 5-HT3 antagonist. Morphine at 30 microM shifted the concentration-response curve for Igly to the right without affecting the maximum value. The effect of morphine on Igly showed no use-dependence. The results indicate that morphine inhibits Igly in the NTS neurones, and further suggest that morphine at the concentration used may act on the glycine receptor-ionophore complex, but not on the Cl-channel of the complex.

Animals↗
PubMed1998

[A case of familial myoclonus showing extremely benign clinical course].

We report a patient with familial myoclonus showing an extremely benign clinical course. The patient was a 70-year-old woman, who first noticed shaking of hands at age of 25. The symptom did not worsen for more than 40 years. She visited our hospital at the age of 70 because of disturbance in chores because of worsening of her hand shaking in the past one year. A family history showed that 4 members had similar symptoms and that the two were afflicted with fits of loss of consciousness. On neurologic examination, rhythmic myoclonic jerks were noted in all the extremities, more in the upper limbs, both at rest and during action. Tandem gait was mildly disturbed. The remainings of neurologic examination were normal. SEP and jerk-locked back averaging provided evidence of cortical myoclonus. EEG showed multifocal polyspike discharges. Gene analysis for DRPLA, pyruvate and lactate levels in serum and the cerebrospinal fluid, serum amino acid levels, and CSF HVA and 5-HIAA levels were all normal. No brain atrophy was noted in cranial MRI. Myoclonus was markedly reduced after administration of clonazepam. The clinical features and electrophysiological data of our patient are consistent with the clinical diagnosis of familial essential myoclonus and epilepsy/benign adult familial myoclonic epilepsy.

Aged↗
PubMed1997

Enhancement of an inhibitory input to the feeding central pattern generator in Lymnaea stagnalis during conditioned taste-aversion learning.

To study the neuronal mechanism of a conditioned taste-aversion (CTA) learning in the pond snail Lymnaea stagnalis, we examined the synaptic connection between the neuron 1 medial (N1M) cell and the cerebral giant cell (CGC), the former is an interneuron in central pattern generator for the feeding response and the latter is a regulatory neuron to the central pattern generator. Inhibitory postsynaptic potential (IPSP) which was evoked in the N1M cell by activation of the CGC was larger and lasted longer in the conditioned animal than that in the control animal. The electrical properties of the cell body of CGC and the responses of the CGC to the chemosensory inputs were not changed during the CTA learning. These results, together with the previous report indicating the existence of excitatory projection from the N1M cell to the feeding motoneuron, suggest that enhanced IPSP in the N1M cell may underlie the suppression of feeding responses in the Lymnaea CTA learning.

Animals↗
PubMed1997

Lethal drug interactions of sorivudine, a new antiviral drug, with oral 5-fluorouracil prodrugs.

Rats were orally co-administered sorivudine (SRV: 1-beta-D-arabinofuranosyl-(E)-5-(2-bromovinyl)uracil), a new oral antiviral drug for herpes zoster, with the oral anticancer drug tegafur (FT: 1-(2-tetrahydrofuryl)-5-fluorouracil) as a prodrug of 5-flourouracil (5-FU) once daily to investigate a toxicokinetic mechanism of 15 Japanese patients' deaths recently caused within a brief period by the drug interaction of these drugs. All the rats showed extremely elevated levels of 5-FU in plasma and tissues, including bone marrow and small intestine, and died within 10 days, whereas the animals given the same dose of SRV or FT alone were still alive over 20 days without any appreciable toxic symptom. Before their death, there was marked damage of bone marrow, marked atrophy of intestinal membrane mucosa, marked decreases in white blood cells and platelets, diarrhea with bloody flux, and severe anorexia as reported with the Japanese patients. Data obtained by in vivo and in vitro studies strongly suggested that (E)-5-(2-bromovinyl)uracil generated from SRV by gut flora was reduced in the presense of NADPH to a reactive form by hepatic dihydropyrimidine dehydrogenase (DPD), a key enzyme determining the tissue 5-FU levels, bound covalently to DPD as a suicide inhibitor, and markedly retarded the catabolism of 5-FU.

Administration, Oral↗
PubMed1997

Lethal drug interactions of sorivudine, a new antiviral drug, with oral 5-fluorouracil prodrugs.

Rats were orally co-administered sorivudine (SRV: 1-beta-D-arabinofuranosyl-(E)-5-(2-bromovinyl)uracil), a new oral antiviral drug for herpes zoster, with the oral anticancer drug tegafur (FT: 1-(2-tetrahydrofuryl)-5-fluorouracil as a prodrug of 5-fluorouracil (5-FU) once daily to investigate a toxicokinetic mechanism of 15 Japanese patients' deaths recently caused within a brief period by the drug interaction of these drugs. All the rats showed extremely elevated levels of 5-FU in plasma and tissues, including bone marrow and small intestine, and died within 10 days, whereas the animals given the same dose of SRV or FT alone were still alive over 20 days without any appreciable toxic symptom. Before their death, there was marked damage of bone marrow, marked atrophy of intestinal membrane mucosa, marked decreases in white blood cells and platelets, diarrhea with bloody flux, and severe anorexia as reported with the Japanese patients. Data obtained by in vivo and in vitro studies strongly suggested that (E)-5-(2-bromovinyl)uracil generated from SRV by gut flora was reduced in the presense of NADPH to a reactive form by hepatic dihydropyrimidine dehydrogenase (DPD), a key enzyme determining the tissue 5-FU levels, bound covalently to DPD as a suicide inhibitor, and markedly retarded the catabolism of 5-FU.

Animals↗
PubMed1997

[A case of axonal form of Guillain-Barré syndrome associated with anti-GM1b IgG antibody following Penner 4 Campylobacter jejuni infection].

A 41-year-old woman was admitted to the hospital because of diarrhea followed by progressive weakness of all extremities and dysphagia. On neurological examination, she showed facial diplegia, bulbar palsy, flaccid quadriplegia, and absence of all deep tendon reflexes in addition to Laségue's sign. The Campylobacter jejuni Penner type 4 was isolated from the culture of stool. The test of anti-GM1b antibody (IgG) was positive in the serum. The protein content was elevated in the cerebrospinal fluid without pleocytosis. The studies of motor nerve conduction velocity showed a pattern of the axonal neuropathy. This is a case of Guillain-Barré syndrome presenting with the axonal neuropathy possibly due to the immune response directed to GM1b which is triggered by the Campylobacter jejuni Penner type 4 infection.

Adult↗
PubMed1995

Occurrence of autoimmune antibodies to liver microsomal proteins associated with lethal hepatitis in LEC rats: effects of TJN-101 ((+)-(6S,7S,R-biar)- 5,6,7,8-tetrahydro-1,2,3,12-tetramethoxy-6,7-dimethyl-10,11- methylenedioxy-6-dibenzo[a,c]cyclooctenol) on the development of hepatitis and the autoantibodies.

Long Evans Cinnamon (LEC) rats, that spontaneously develop hepatitis, were found to possess autoantibodies to liver microsomal proteins (anti-LM) before the development of hepatitis. Anti-LM antibody was assumed to appear in association with the lethal hepatitis in the LEC rats. Thus, the purpose of this study was to investigate the effects of an anti-hepatitis drug on the development of hepatitis and the occurrence of the antibody in LEC rats. Mortality, blood biochemical parameters and the titer of serum anti-LM antibody were measured. In control LEC rats, 4 of 8 rats died before 20 weeks of age. In rats treated with TJN-101 ((+)-(6S,7S,R-biar)-5,6,7,8-tetrahydro-1,2,3,12-tetramethoxy -6,7-dimethyl-10,11 - methylenedioxy-6-dibenzo[a,c]cyclooctenol), 4 of 7 rats died of hepatitis, but the time of death was delayed by 7-10 weeks compared to the control rats. The titer of the anti-LM antibody increased 3-7 weeks before death in the non-survivors in control and TJN-101-treated rats, supporting the idea that anti-LM antibody occurs in association with acute lethal hepatitis.

Animals↗
PubMed1994

Occurrence of autoantibody to protein disulfide isomerase in rats with xenobiotic-induced hepatitis.

The occurrence of an autoantibody to protein disulfide isomerase (PDI) in rats after administration of various hepatotoxic drugs was investigated by immunoblotting and radioimmunoassay. An anti-PDI autoantibody was detected with high frequency in rats treated with D-galactosamine, acetaminophen with diethylmaleate, and carbon tetrachloride with diethylmaleate. The antibody-positive rate was relatively low in the groups of rats given carbon tetrachloride, acetaminophen or DL-ethionine alone. The anti-PDI antibody was not detected in rats treated with diethylmaleate alone. Although the mechanism of the production of the anti-PDI autoantibody is unclear, the occurrence of anti-PDI antibody correlated with high serum GPT activities. It is suggested that the autoantibody plays an important role in the development and persistence of drug-induced hepatitis.

Alanine Transaminase↗
PubMed1994

Occurrence of autoantibody to protein disulfide isomerase in patients with hepatic disorder.

The occurrence of autoantibody to protein disulfide isomerase (PDI) was examined in sera from patients with alcoholic liver disease, liver cirrhosis, systemic lupus erythmatosus (SLE) and cancer. Judging by results of Western blotting using a purified preparation of PDI, the anti-PDI antibody was hardly seen in most sera from healthy controls but was raised in patients with alcoholic liver disease, liver cirrhosis, SLE and liver cancer. When the antibody titer to PDI was measured by radioactivity in a radioimmunoassay, positive values (cut off value; mean + 2SD = 256 cpm) were seen in 46% (11/24) of the patients with moderate alcoholic liver disease (mean radioactivity, 339 cpm) and in 54% (7/13) of those with severe alcoholic liver disease (mean radioactivity, 664 cpm). Only 8% (4/48) of the healthy controls were positive (mean radioactivity, 50 cpm). Four of six patients with hepatoma were positive, while none of the seven patients with non-hepatic cancer were positive. The positive proportions in the patients with liver cirrhosis and SLE were 64% (9/14) and 40% (4/10), respectively. These results suggest that the occurrence of anti-PDI antibody would play an immunological role in the progression of hepatic disorders.

Adult↗
PubMed1994

Effects of cyclosporin-A and D-penicillamine on the development of hepatitis and the production of antibody to protein disulfide isomerase in LEC rats.

Long Evans Cinnamon (LEC) rats, which spontaneously develop hepatitis, produce an autoantibody to protein disulfide isomerase (PDI) before the development of clinical signs of hepatitis. Anti-PDI antibody may be associated with immunological hepatitis. Thus, the purpose of this study was to investigate the effects of some drugs on the development of hepatitis and the occurrence of the antibody in LEC rats. Cyclosporin-A, an immunosuppressant, and D-penicillamine, which promotes copper excretion, were orally administered to LEC rats for 23 weeks. Mortality, blood biochemical parameters and the titer of serum anti-PDI antibody were measured. In control LEC rats, four of eight rats died before 20-weeks-old. Only one of seven rats in the cyclosporin-A-treated group died at the age of 20 weeks. When rats were treated with D-penicillamine, the development of clinical signs of hepatitis was inhibited, and all rats survived. Cyclosporin-A-treated rats showed increases in blood biochemical parameters similar to those in control rats. The titer of anti-PDI antibody in control rats was higher the non-survivors than survivors. These findings suggest the association of the anti-PDI antibody with lethality, but not with the apparent development and progression of hepatitis as measured by blood biochemical parameters in LEC rats.

Administration, Oral↗
PubMed1994

[A case of dementia associated with multiple iron deposits in the brain on MRI].

We report a 63-year-old man presenting with dementia and cerebellar ataxia associated with multiple iron deposits in the brain on MRI. Numerous small lesions of low-intensity on both T1- and T2-weighted images were found in the parenchyma and surface of the cerebrum, cerebellum and brain stem. The number and size of lesions were increased on MRI with the method of gradient recalled acquisition in the steady state (GRASS), indicating that they were composed of iron. The similar lesions were not found in any organs on the abdominal GRASS-MRI. Any abnormalities were also not found in the cerebral angiography. Meanwhile, the protein and IgG levels and activated CD4-cells were increased in the cerebrospinal fluid, indicating the involvement of chronic inflammation in the iron deposits in this case.

Brain↗
PubMed1993

Identification of protein disulfide isomerase and calreticulin as autoimmune antigens in LEC strain of rats.

Long Evans Cinnamon (LEC) rats, showing spontaneous hereditary hepatitis and hepatic carcinoma, were found to possess autoimmune antibodies to liver microsomal proteins, particularly to proteins with the molecular weight of 56kD and 55kD. The antibodies occurred in association with acute lethal hepatitis in the LEC rats in our previous study. Two-dimensional immunoblot analysis of the antigenic proteins revealed that the 56kDa and 55kDa proteins showed 4.2 and 4.0 pI values and were estimated to be protein disulfide isomerase (PDI) and calreticulin, respectively, from NH2-terminal amino acid sequence analysis. These proteins were further identified by immunoblot analyses using purified proteins and specific antibodies. PDI was a major autoimmune antigenic protein.

Amino Acid Sequence↗