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Biomedical subjects

M Goto

Publications and source records attributed to M Goto.

At least 325 records · Page 18Linked to original sources
PubMed1998

Effects of 5-hydroxytryptamine on neuronal activities in the rat dorsolateral septal nucleus.

The ionic channels and signal transduction pathways underlying the 5-hydroxytryptamine (5-HT)-induced hyperpolarization in neurons of the rat dorsolateral septal nucleus (DLSN) were examined by using intracellular and voltage-clamp recording techniques. Application of 5-HT (1-50 microM) caused a hyperpolarizing response associated with a decreased membrane resistance in DLSN neurons. The hyperpolarization induced by 5-HT was blocked by Ba2+ (1 mM) but not by tetraethylammonium (TEA, 3 mM), glibenclamide (100 microM) and extracellular Cs+ (2 mM). 8-Hydroxy-di-n-propylamino tetralin (8-OH-DPAT; 3 microM), a selective agonist for the 5-HT1A receptor, mimicked 5-HT in producing the hyperpolarization. The 5-HT hyperpolarization was blocked by NAN-190 (5 microM), a 5-HT1A receptor antagonist. CP93129 (100 microM), a 5-HT1B receptor agonist, and L-694-247 (100 microM), a 5-HT1B/1D receptor agonist, also produced hyperpolarizing responses. The order of agonist potency was 8-OH-DPAT >> CP93129 > or = L-694-247. (+/-)-2,5-Dimethoxy-4-iodoamphetamine hydrochloride (DOI, 100 microM), a 5-HT2 receptor agonist, and RS67333 (100 microM), a 5-HT4 receptor agonist, caused no hyperpolarizing response. The voltage-clamp study showed that 5-HT caused an outward current (I5-HT) in a concentration-dependent manner. I5-HT was associated with an increased membrane conductance. I5-HT reversed the polarity at the equilibrium potential for K+ calculated by the Nernst equation. I5-HT showed inward rectification at membrane potentials more negative than-70 mV. Ba2+ (100 microM) blocked the inward rectifier K+ current induced by 5-HT. I5-HT was irreversibly depressed by intracellular application of guanosine 5'-O-(3-thiotriphosphate)(GTP-gamma S) but not by guanosine 5'-O-(2-thiodiphosphate) (GDP beta S). These results suggest that in rat DLSN neurons activation of 5-HT1A receptors causes a hyperpolarizing response by activating mainly the inward rectifier K+ channels through a GTP-binding protein.

Animals↗
PubMed1998

Characterization of the nuclear localization signal in the DNA helicase involved in Werner's syndrome.

The nuclear localization signal (NLS) of the DNA helicase involved in Werner's syndrome (WS) was studied. Previously, we noted that the C-terminal region of WS helicase contains the NLS. In this study, we generated in HeLa cells various chimeric proteins consisting of the N-terminal tagged with an enhanced green fluorescent protein and the C-terminal fragments of the WS helicase that were truncated either from N- or C-termini, and we examined the ability of fragments to transfer the fusion proteins to the nucleoplasm by fluorescence microscopy. A small C-proximal region containing 34 amino acid residues (residues 1369-1402) was found to contain full nuclear migration activities. Subsequent amino acid substitution experiments showed that a sequence of three positively charged amino acids (Lys1371-Arg1372-Arg1373) in this region are particularly important. Similar sequence has previously been defined as the nuclear localization signal of SV-40 large T antigen that also acts as a viral DNA helicase. Conservation of this motif was found in the C-terminal regions of the other RecQ type DNA helicases, including murine WS helicase, yeast sgs1 and rqh+1 and human Bloom syndrome DNA helicases.

Adenosine Triphosphatases↗
PubMed1998

[Chemotherapy of Hansen's disease in Japan--present status].

In order to know leprosy chemotherapy status in Japan, three recently conducted Government-supported nation-wide survey, namely chemotherapy research group survey (Takizawa, 1994, 71 cases) follow up result of Takizawa's study (Miyagi, 1997, 59 cases) and leprosy patient registry (Goto, 1996, 130 cases) were compared and analyzed. For most fresh and relapse cases, multi-drug therapy were applied, among them rifampicin/dapsone or rifampicin/dapsone/clofazimine combinations were selected in about half of new cases and about 1/3 of relapse cases. In many cases dose and intervals were based on WHO protocol, however smaller dosage was used in some cases. Quinolone (ofloxacin) was used in 40% of cases during the therapy. Reversal reaction was observed in 7/71 cases and erythema nodosum leprosum was observed in 6/71 cases. In order to prevent chemotherapy-induced deformities, we propose a modified protocol for new cases accompanied by reactional status, which starts with clofazimine monotherapy and followed by WHO/MB.

Anti-Infective Agents↗
PubMed1998

K1115 A, a new anthraquinone derivative that inhibits the binding of activator protein-1 (AP-1) to its recognition sites. I. Biological activities.

K1115 A, a new anthraquinone derivative, was isolated from the culture broth of Streptomyces griseorubiginosus (Mer-K1115). K1115A inhibited the direct binding of activator protein-1 (AP-1) to AP-1 oligonucleotide (IC50 = 100 microM), and the production of collagenase in IL-1 alpha-stimulated rat synovial cells (IC50 = 60 microM). In vivo, the application of K1115 A decreased phorbol myristate acetate (PMA)-induced mouse ornithine decarboxylase (ODC) activity. These results indicated that K1115 A is able to attenuate the inflammatory response mediated by AP-1.

Animals↗
PubMed1998

K1115 A, a new anthraquinone that inhibits the binding of activator protein-1 (AP-1) to its recognition sites. II. Taxonomy, fermentation, isolation, physico-chemical properties and structure determination.

A new inhibitor of the action of activator protein-1 (AP-1), designated K1115 A, was isolated from the fermentation broth of an actinomycete strain Mer-K1115. K1115 A was determined to be a new anthraquinone, 3,8-dihydroxy-1-propylanthraquinone-2-carboxylic acid, based on spectroscopic analysis, derivatization experiments and biosynthetic studies with 13C-enriched acetic acid. Two co-produced compounds, K1115 B1 and B2, were also isolated and characterized as new members of the naphthopyranomycin and exfoliamycin group.

Anthraquinones↗
PubMed1998

[Neurologic outcomes for infants weighing less than 1,000 grams at birth].

We evaluated the neurologic outcomes of 107 infants with birth weights of less than 1,000g who had been admitted to our hospital from October 1981 to March 1986. Their outcomes were confirmed during a follow-up period of 20-39 years (mean: 75 years). The diagnoses were normal in 71, cerebral palsy in 13, mental retardation in 11, borderline intelligence in 11, and spinal palsy due to birth injury in 1. Only 3 infants with cerebral palsy had developed epilepsy. Among the infants with birth weights of less than 1,000g hospitalized in this tertiary care center, about one-third still had some major or minor neurologic abnormalities.

Brain↗
PubMed1998

Effects of hydrazine sulfate on galactosamine-sensitized endotoxic shock in ten-day-old rats.

Patients who have liver diseases are susceptible to septic shock. Galactosamine induces liver damage and increases endotoxin-sensitivity. Hydrazine stimulates pituitary-adrenal axis and decreases mortality in galactosamine-sensitized endotoxic shock in the adult. However, as pituitary-adrenal function in the newborn is immature, the effects of hydrazine on galactosamine-sensitized endotoxic shock in the newborn remained unclear. In the present study, galactosamine-sensitized endotoxic shock was induced and treated with hydrazine in ten-day-old rats. Galactosamine (600 mg/kg) plus Salmonella enteritidis lipopolysaccharide (LPS; 0.01 mg/kg) induced hypoglycemia, lactacidemia and resulted in high mortality. Hydrazine at the dose of 20, 50 or 80 mg/kg did not alter the hypoglycemia, lactacidemia or morality. Dexamethasone ameliorated the hypoglycemia and lactacidemia (p < 0.05) and decreased the morality (p < 0.05). The lack of beneficial effects of hydrazine in galactosamine-sensitized endotoxic shock in ten-day-old rats may be related to immature pituitary-adrenal function and suppression of gluconeogenesis by hydrazine.

Animals↗
PubMed1998

[Respiratory symptoms by oral challenge tests with egg white antigens in egg-allergic children].

One hundred and ninety one subjects showing histories of immediate hypersensitive response to egg white ingestion and/or positive IgE antibody titers specific for egg white were enrolled in double-blind placebo-controlled oral challenge with freeze and dried, heated or heated and ovomucoid-depleted egg white antigens. Seventy seven were male and 114 female, and their ages ranged from 11 month to 10 years 5 month; 118 of them had atopic dermatitis, seven had asthma and 33 had both atopic dermatitis and bronchial asthma and 33 had urticaria. One hundred four children developed 147 positive symptoms including 131 immediate reactions and 16 non-immediate reactions by oral challenge tests. Respiratory symptoms were observed in 25 cases (17%) including cough alone in 12 cases (8.2%), and both wheezing and cough in 13 cases (8.8%). These were all observed as immediate reactions and accompanied with dermal symptoms. Frequency of respiratory symptoms correlated with specific IgE antibody titers for egg white. Heated and ovomucoid-depleted egg white was more hypoallergenic that heated or freeze and dried egg white with respect to respiratory symptoms as well as other symptoms. We concluded that respiratory symptoms were provoked through oral challenges with egg white in a part of egg-allergic children.

Administration, Oral↗
PubMed1998

[A case of congenital toxoplasmosis confirmed by detection of Toxoplasma gondii in placenta].

We report a case of congenital toxoplasmosis with a prenatal diagnosis of fetal hydrocephalus. A CT scan performed at birth revealed ventricular dilation with calcification. The serum and CSF Toxoplasma specific IgM were elevated. The diagnosis was confirmed by the presence of Toxoplasma cysts in the placenta, and detection of the Toxoplasma SAG1 gene by a polymerase chain reaction (PCR) (placenta, positive; CSF, negative). Signs of active central nervous system infection, such as the decreased CSF glucose, and elevated CSF protein, neuron specific enolase and LDH, resolved after initiation of treatment with pyrimethamine and sulfazoxine. A PCR test using the placental tissue may be useful for the rapid diagnosis of congenital toxoplasmosis.

Adult↗
PubMed1998

[A case of primary Sjögren's syndrome accompanied by transverse myelitis].

Here we report a case of Sjögren's syndrome (SS) accompanied by transverse myelitis. A 46-year-old woman with 7-year history of primary SS was admitted to Tokyo Metropolitan Ohtsuka Hospital in September 1997 because of muscular weakness in lower extremities. She had had a low grade fever, numbness, and pain in bilateral lower extremities since July 1992. Neurological examination revealed transverse myelopathy at the level of Th 4, and peripheral neuropathy in lower extremities. Cerebrospinal fluid analysis showed slight elevation of protein and the cell count. A diagnosis of transverse myelitis and peripheral neuropathy presenting as neurologic manifestations of SS was made. Treatment was initiated with 30 mg of prednisolone, followed by improvement of fever and neurological findings. Although central nervous system complications of SS have been presented in Western countries, little information is available about Japanese patients. To our knowledge, this is the second case report which describes the occurrence of transverse myelitis in Japanese patients with SS.

Anti-Inflammatory Agents↗
PubMed1997

Abnormal telomere dynamics of B-lymphoblastoid cell strains from Werner's syndrome patients transformed by Epstein-Barr virus.

The characteristics of B-lymphoblastoid cell strains transformed by Epstein-Barr virus (EBV) from normal individuals and Werner's syndrome (WRN) patients were compared. We continuously passaged cell strains from 28 WRN patients and 20 normal individuals for about 2 years corresponding to over 160 population doubling levels (PDLs). First, the WRN mutation significantly suppressed the immortalization: all the 28 cell strains from WRN patients, as well as 15 out of 20 cell strains from normal individuals, died out before 160 PDLs mostly without developing a significant telomerase activity. The remaining five cell strains from normal individuals became moderately/strongly telomerase-positive and, three of them were apparently immortalized with an infinitively proliferating activity. Second, the monitoring of the telomere length of both normal and WRN cell strains during the culture period suggests that the WRN gene mutation causes abnormal dynamics of the telomere: (1) a significant proportion of WRN cell strains showed drastic shortening or lengthening of telomere lengths during cell passages compared with normal cell strains, and (2) WRN cell strains terminated their life-span at a wide range of telomere length (between 3.5 and 18.5 Kbp), whereas normal cell strains terminated within a narrow telomere length range (between 5.5 and 9 Kbp). The chromosomal aberration characteristic of WRN cells, including translocation was confirmed in our experiment. We discussed the correlation between the chromosomal instability, abnormal telomere dynamics and inability of immortalization of the WRN B-lymphobloastoid cell strains.

B-Lymphocytes↗
PubMed1997

Inhibitory mechanisms of beta-adrenoceptor agonists for immunoglobulin E-mediated experimental allergic reactions in rats.

Inhibitory mechanisms of isoproterenol and clenbuterol for immunoglobulin E (IgE)-mediated experimental allergic reactions in rats were studied. IgE-mediated passive cutaneous anaphylaxis, histamine-induced cutaneous reaction and serotonin-induced cutaneous reaction were evoked at the same time in the same rats. Isoproterenol administered intravenously immediately before challenge inhibited all these reactions significantly. Clenbuterol administered intravenously 0-3 h before challenge also significantly inhibited the three cutaneous reactions. The inhibition was maximum when the drug was given 1 h before challenge. Passive cutaneous anaphylaxis was always inhibited more potently than histamine-induced cutaneous reaction and serotonin-induced cutaneous reaction by these beta-adrenoceptor agonists. Passive peritoneal anaphylaxis was caused by injecting an antigen intravenously. Isoproterenol administered intravenously immediately before challenge inhibited the reaction significantly. Clenbuterol administered intravenously 0-3 h before challenge also significantly inhibited passive peritoneal anaphylaxis, maximally so when given 1 h before challenge. In vitro IgE-dependent histamine release from sensitized peritoneal mast cells or mesenteric mast cells was not affected by isoproterenol and clenbuterol. Mouse monoclonal IgE, a foreign protein, administered intravenously decreased rapidly in the circulation. About 50% of the mouse IgE given disappeared in 20 min. The decrease of mouse IgE was partly but significantly inhibited by the beta-adrenoceptor agonists, and the inhibition was abolished by simultaneous treatment with propranolol. These results indicate that direct inhibition of mast cell activation does not contribute to the potent inhibition of in vivo allergic reactions in rats by beta-adrenoceptor agonists, and that inhibition of the allergic cutaneous reaction is partially explained by the inhibition of vascular permeability increases caused by mast cell mediators. Penetration of intravenously administered antigen from blood vessels to peripheral tissues to cause mast cell activation might be inhibited by beta-adrenoceptor agonists, and this could play some role in inhibiting intravenous antigen-induced allergic reactions in rats. Clenbuterol exhibited its maximum action with some latency in vivo, suggesting that some time-requiring process may be involved in the manifestation of its action.

Adrenergic beta-Agonists↗
PubMed1997

Molecular evidence from retroposons that whales form a clade within even-toed ungulates.

The origin of whales and their transition from terrestrial life to a fully aquatic existence has been studied in depth. Palaeontological, morphological and molecular studies suggest that the order Cetacea (whales, dolphins and porpoises) is more closely related to the order Artiodactyla (even-toed ungulates, including cows, camels and pigs) than to other ungulate orders. The traditional view that the order Artiodactyla is monophyletic has been challenged by molecular analyses of variations in mitochondrial and nuclear DNA. We have characterized two families of short interspersed elements (SINEs) that were present exclusively in the genomes of whales, ruminants and hippopotamuses, but not in those of camels and pigs. We made an extensive survey of retropositional events that might have occurred during the divergence of whales and even-toed ungulates. We have characterized nine retropositional events of a SINE unit, each of which provides phylogenetic resolution of the relationships among whales, ruminants, hippopotamuses and pigs. Our data provide evidence that whales, ruminants and hippopotamuses form a monophyletic group.

Animals↗
PubMed1997

DNA helicase activity in Werner's syndrome gene product synthesized in a baculovirus system.

The gene responsible for Werner's syndrome (WRN) contains a region homologous to the Escherichia coli RecQ type DNA helicase and was thought to code for a DNA helicase belonging to this helicase family. However, no evidence has been shown before to substantiate this prediction. Here, we show data that the product of the WRN gene is indeed a DNA helicase. The gene product, a polypeptide with a relative molecular mass of 170 kDa, expressed in the insect Spodoptera frugiperda (Sf21) cell and purified by affinity column chromatography contained both the ATPase and DNA unwinding activities characteristic of DNA helicase. Expressions in Sf21, as well as in HeLa cells, showed that the WRN DNA helicase is exclusively transported to the nucleoplasm, which is consistent with its function in DNA metabolism. Our studies on strand displacement suggest that WRN helicase can unwind not only a duplex DNA, but also an RNA-DNA heteroduplex, while the latter reaction seems less efficient. Enzymological features learned from the purified WRN helicase are discussed with respect to the biological function, which remains to be clarified.

Adenosine Triphosphatases↗
PubMed1997

Retinoblastoma binding factor 1 site in the core promoter region of the human RB gene is activated by hGABP/E4TF1.

We previously reported two oncogenic point mutations present in the RB (retinoblastoma) gene promoter region, found at consensus Sp1 and ATF sites, respectively, and in two separate hereditary RB families. However, Sp1 protein was shown not to bind to the Sp1 site; this indicated that the Sp1 consensus site mutation was blocking the action of an alternative transcription factor, which we called RBF-1 (retinoblastoma binding factor 1). Subsequent purification of RBF-1 revealed it to be hGABP/E4TF1, a transactivator from the adenovirus early-region 4 promoter. In this study, we directly examined the effects of hGABP/E4TF1 on transactivation of the RB gene promoter through the RBF-1 site. As expected, hGABP/E4TF1 enhanced the core RB promoter activity, whereas it did not stimulate a mutant RBF-1 site. We therefore conclude that the most essential transcription factor in the human RB gene is likely to be hGABP/E4TF1.

Animals↗
PubMed1997

Phenotype and localization of macrophages expressing inducible nitric oxide synthase in rat hepatic allograft rejection.

BACKGROUND: We investigated the phenotype and localization of macrophages expressing inducible nitric oxide synthase (iNOS) in rat hepatic allografts, using double immunostaining with anti-macrophage iNOS (macNOS) and rat anti-macrophage (ED1 or ED2) monoclonal antibodies. METHODS: The animals were divided into three experimental groups: group 1, isografts; group 2, untreated hepatic allografts; and group 3, hepatic allografts treated with FK506. RESULTS: Plasma nitrite/nitrate concentrations in group 2 increased on day 3, peaked on day 5, and decreased thereafter. In contrast, the plasma nitrite/nitrate concentrations in group 1 increased slightly on day 3, but decreased gradually thereafter. The plasma concentrations of nitrite/nitrate did not vary in group 3. The peak nitrite/nitrate values in group 2 were significantly greater than those in groups 1 and 3. The number of macNOS+ cells peaked on day 5 in group 2. In contrast, a few macNOS+ cells were seen in the liver grafts of groups 1 and 3. Double immunostaining revealed that the macNOS+ cells consisted of macNOS+ ED1+ (80%) and macNOS+ ED2+ (40%) in the untreated hepatic allografts on day 5. In addition, a number of macNOS+ cells also were seen in the red pulp of the recipient spleen in the untreated hepatic allografts. CONCLUSIONS: These results suggest that the intense iNOS expression by the monocyte/macrophage lineage among the hepatic infiltrates and by the splenic macrophages after transplantation supports a role for nitric oxide in the immunomodulation of allogeneic responses in local and remote organs, and possibly serves as a mediator of cytotoxic graft damage.

Animals↗
PubMed1997

Down-regulation of the defective transcripts of the Werner's syndrome gene in the cells of patients.

Werner's syndrome (WS), an adult progeria, is a recessive genetic disorder caused by the mutations in the DNA helicase gene (WRN). In this study, a comparative northern blot analysis was made for poly(A)+ RNAs extracted from fibroblasts and B-lymphoblastoid cells of WS patients, relatives of patients, and normal individuals. The levels of mutant WRN mRNA from patient cells were significantly lower than those of intact mRNA from the cells of normal individuals by an average of 70%. Furthermore, an extremely low level of WRN mRNA(s), presumably a mixture of mutant and intact mRNAs, was observed for the patient's family members who carry one mutated allele. These results strongly suggest that a relatively low level of helicase mRNA is sufficient to prevent the onset of Werner's syndrome.

Adult↗