Search PubMed⌕ Search

Biomedical subjects

M Ota

Publications and source records attributed to M Ota.

At least 235 records · Page 13Linked to original sources
PubMed1991

Effects of morphine administration on catecholamine levels in rat brain; specific reduction of epinephrine concentration in hypothalamus.

The effects of morphine administration on concentrations of epinephrine, norepinephrine and dopamine were examined in the rat brain. Morphine injection reduced the epinephrine level only in the hypothalamus, while the norepinephrine level was reduced in the hypothalamus, medulla, and locus coeruleus. The dopamine concentration was elevated in all regions examined. These changes were blocked by administration of naloxone. Repeated injection of morphine for 14 days did not affect any catecholamine level. In naloxone-induced withdrawal, epinephrine was most markedly depleted in hypothalamus. These observations suggest that the epinephrine level in hypothalamus is affected by morphine acting on opioid receptors.

Animals↗
PubMed1991

Calcium phosphate naturally formed on titanium in electrolyte solution.

Surface films formed on titanium specimens immersed in electrolyte solutions (pH 4.5, 5.2, 7.4) at 37 degrees C for 1 h, 1 d, 30 d, and/or 60 d, were characterized using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared reflection absorption spectroscopy (FTIR-RAS) to understand the reaction between titanium and inorganic ions. For comparison, the surface of Ti-6AI-4V and Ti-50Ni were also characterized. XPS data revealed that calcium phosphates were naturally formed on these specimens. In particular, compared with the calcium phosphates formed on the titanium alloys, the calcium phosphate formed on titanium immersed for 30 d in the solution with pH 7.4 was more like hydroxyapatite. The compositions of the calcium phosphates formed on the specimens changed with the immersion time and the pH value of the solution. The spectrum obtained using FTIR-RAS from titanium immersed in the solution with pH 7.4 for 60 d was similar to that obtained from carbonate-containing hydroxyapatite. The results indicate that a calcium phosphate similar to apatite is naturally formed on titanium in a neutral electrolyte solution in 30 d. In regard to titanium being a biomaterial, we found this to be an intriguing property. It is possible that this calcium phosphate is responsible for the resulting biocompatibility of titanium.

Alloys↗
PubMed1991

Severe acute graft-versus-host disease by HLA-DPB1 disparity in recombinant family of bone marrow transplantation between serologically HLA-identical siblings: an application of the polymerase chain reaction-restriction fragment length polymorphism method.

It has remained to be established that matching of the HLA-DP antigen plays a key role in bone marrow transplantation (BMT), mainly due to the difficulty of the primed lymphocyte test (PLT) method for DP typing. We previously reported an efficient technique for HLA class II genotyping, by digestion of polymerase chain reaction (PCR)-amplified genes with restriction fragment length polymorphisms (RFLP) endonucleases (PCR-RFLP method). DNAs from 46 recipients and corresponding donors in serologically HLA-identical sibling-BMT cases were DP typed by this PCR-RFLP method. Of the 46 cases, five (10.9%) were genetically DP mismatched (recombinant frequency between the DR-DQ and DP subregions was at least 2.7% per meiosis), providing an important opportunity to look at the effect of the disparity only seen in the DP antigen on BMT. Three of the four DP-mismatched BMT cases that could be evaluated developed severe acute graft-versus-host disease, suggesting that DP disparity played an important role in BMT.

Acute Disease↗
PubMed1991

Modification of gonadectomy-induced increases in brain monoamine metabolism by steroid hormones in male and female rats.

Concentrations of monoamines (dopamine, DA; serotonin, 5-HT) and their major metabolites (homovanillic acid--HVA; dihydroxyphenylacetic acid--DOPAC; 5-hydroxyindolacetic acid--5-HIAA) were measured in selected brain areas of chronically gonadectomized, steroid- or oil-treated male and female rats. Concentrations of DOPAC and HVA were markedly increased in the hypothalamus (male, female), striatum (male, female) and brainstem (male) following gonadectomy, whereas the levels of DA remained unaltered in most of the brain areas examined. Most of the changes were reversed or attenuated by chronic estradiol (EB) substitution. In contrast, chronic treatment with physiological concentrations of testosterone (TP) reduced indexes of DA turnover only in the striatum of ovariectomized (OVX) and brainstem of orchidectomized (ORDX) rats. ORDX-related increases in striatal levels of DOPAC and HVA were not reversed by either EB or TP. ORDX increased the levels of 5-HIAA (hypothalamus, striatum) and decreased those of 5-HT (hypothalamus, hippocampus). These changes were reversed by chronic treatment with either TP or EB. Brain metabolism of 5-HT remained unaltered following OVX. Gonadectomy and chronic steroid replacement therapy appear to alter brain monoamine metabolism in a brain region and sex-dependent manner. Our data demonstrate that gonadectomy-related increases in the activity of brain monoaminergic neurons in both male and female rats was attenuated more effectively with physiological concentrations of estradiol than with testosterone. Insensitivity of monoaminergic neurons in a number of brain areas (e.g., hypothalamus, striatum) to the action of testosterone was evident in both sexes.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

The Mr 90,000 heat shock protein-free androgen receptor has a high affinity for steroid, in contrast to the glucocorticoid receptor.

Transformed and bacterially expressed glucocorticoid receptors free from Mr 90,000 heat shock protein (hsp90) have a 100-fold lower steroid-binding affinity than the hsp90-bound nontransformed receptor, suggesting that hsp90 is needed for high-affinity steroid binding [Nemoto, T., Ohara-Nemoto, Y., Denis, M., & Gustafsson, J.-A. (1990) Biochemistry 29, 1880-1886]. To investigate whether or not this phenomenon is common to all steroid receptors, we investigated the steroid-binding affinities of bacterially expressed and transformed androgen receptors. The C-terminal portion of the rat androgen receptor containing the putative steroid-binding domain was expressed as a fusion protein of protein A in Escherichia coli. The recombinant protein bound a synthetic androgen, [3H]R1881, with high affinity (Kd = 0.8 +/- 0.3 nM). Glycerol gradient analysis revealed that the recombinant protein sedimented at around the 3S region irrespective of the presence of molybdate, indicating that the receptor is present in monomeric form. The steroid-free transformed androgen receptor was obtained by exposure of rat submandibular gland cytosol to 0.4 M NaCl in the absence of steroid. High-performance ion-exchange liquid chromatography analysis showed that the transformed androgen receptor bound to [3H]R1881 with high affinity. Thus these observations indicate that, in contrast to the glucocorticoid receptor, hsp90 is not required for the high-affinity steroid binding of the androgen receptor. In addition, the hsp90-free androgen receptor prebound with radioinert R1881 was efficiently relabeled with [3H]R1881, while the triamcinolone acetonide-bound, transformed glucocorticoid receptor failed in ligand exchange. The inability to achieve ligand exchange probably reflects the low steroid-binding affinity of this entity.

Animals↗
PubMed1991

HLA-DQB1 genotyping by a modified PCR-RFLP method combined with group-specific primers.

We previously reported a simple technique for HLA-DQB genotyping by digestion of polymerase chain reaction-amplified genes with restriction endonucleases (PCR-RFLP method). However, this method has some problems in that some heterozygotes cannot be discriminated from each other. Furthermore, concomitantly amplified product derived from the DQB2 gene by the primers used previously also obstructs precise DQB1 genotyping. To resolve these problems, we have developed two different pairs of specific primers for selective amplification of the DQB1 gene and also used restriction endonucleases which have either a single cleavage site or, alternatively, no cleavage site in the amplified DNA region, depending on the HLA-DQB1 alleles, making reading of RFLP band patterns much easier. The second exon of the DQB1 gene was selectively amplified by DQw1 group-specific primers and/or DQw2,3,4 group-specific primers using genomic DNAs from 70 HLA-homozygous B-cell lines and 50 healthy Japanese. Of the seven DQw1-associated DQB1 alleles, six alleles could be defined by digestion of 6 restriction enzymes, although DQB1*0602 and DQB1*0603 could not be discriminated from each other because of unavailability of suitable enzymes. Similarly, all of the six DQw2,3,4-associated DQB1 alleles could be defined by digestion of 5 restriction enzymes. Using this modified PCR-RFLP method, complete DQB1 genotyping of all heterozygotes is possible except for discrimination between DQB1*0602 and 0603. Thus this method is simpler and more practical for a routine DNA typing than the PCR-SSO method or our previous PCR-RFLP method.

Alleles↗
PubMed1991

Modified PCR-RFLP method for HLA-DPB1 and -DQA1 genotyping.

We previously developed a new technique for HLA class II genotyping by digestion of polymerase chain reaction-amplified genes with restriction endonucleases (PCR-RFLP method). This PCR-RFLP method is an efficient and convenient typing technique for class II alleles. However, small fragments or bands located close to each other on polyacrylamide gels sometimes prevent precise analysis of the RFLP bands. Furthermore, the restriction enzymes we have reported in the previous papers are not sufficient to identify the genotypes of all heterozygous individuals. Here, we report an improved PCR-RFLP method using some informative restriction enzymes which have either a single cleavage site or, alternatively, no cleavage site in the amplified DNA region, depending on the HLA alleles, making reading of RFLP band patterns much easier. Each second exon of the HLA-DQA1 or -DPB1 gene was selectively amplified from genomic DNAs of 70 HLA-homozygous B-cell lines and 100 healthy Japanese by PCR. Amplified DNAs were digested with restriction endonucleases and then subjected to electrophoresis assaying simply for cutting, or no cutting, of the DNA. ApaLI, HphI, BsaJI, FokI, MboII and Mn1I can discriminate eight alleles of the DQA1 gene. Similarly 19 alleles of the DPB1 gene can be discriminated with Bsp1286I, FokI, DdeI, BsaJI, BssHII, Cfr13I, RsaI, EcoNI, and AvaII enzymes. This modified PCR-RFLP method can be successfully applied to heterozygotes. Thus, the method is technically simpler and more practical for routine HLA typing work than our previous PCR-RFLP method.

Alleles↗
PubMed1991

Existence of two components in the tonic contraction of rat aorta mediated by alpha 1-adrenoceptor activation.

1. The mechanisms involved in the contraction of rat aorta induced by the activation of alpha 1-adrenoceptors were studied. Phenylephrine induced a phasic contraction in the aorta incubated in Ca2(+)-free medium containing 0.5 mM EGTA. Subsequent addition of Ca2+ induced a tonic contraction, which exhibited a stepwise development, an initial phase lasting 3 to 6 min (tonic-I) followed by a superimposing second phase (tonic-II). 2. 2-Nitro-4-carboxyphenyl-N,N-diphenylcarbamate, which has been reported to inhibit phosphatidylinositol turnover, and H-7, a protein kinase C inhibitor, inhibited the tonic-I phase more effectively than the tonic-II phase. On the other hand, the tonic-II phase was more sensitive to nifedipine and cromakalim. 3. The rate of 45Ca2+ influx during the tonic-I phase in phenylephrine-treated muscles was not different from that in untreated muscles, while that during the tonic-II phase was significantly greater. Nifedipine inhibited the increased 45Ca2+ influx during the tonic-II phase, whereas H-7 did not affect the uptake during either phase. 4. These results suggest that the tonic contraction of rat aorta following alpha 1-adrenoceptor activation involves two different mechanism: one is directly related to consequences of the polyphosphoinositide cascade, probably to protein kinase C, and the other dependent on Ca2+ influx through nifedipine-sensitive Ca2+ channels.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1991

[Surgical indication for T1N2 disease: comparison of survival among resected T1N2, T2 N2 and non-resected T1 (M0) disease].

Based on the outcome of 28 patients with pathologically confirmed T1N2 disease who underwent surgical resection, we evaluated surgical indication for this stage. Twenty three patients underwent complete resection and 5 patients incomplete resection. The histologic type of tumor was adenocarcinoma in 20 patients and squamous cell carcinoma in 8 patients. The 5-year survival rate was 22% for all resected patients and 28% for completely resected patients. These survival rates were better than those (16% and 23%, respectively) in patients with T2N2 disease. However, there was no significant difference of survival among incompletely resected T1 N2, and non-resected T1 (M0) patients. Although 9 of 28 T1N2 patients survival more than 3 years, all but one patient underwent complete resection of tumor and had clinical N0 or N1 before surgery. In conclusion, surgery should be indicated only for patients with completely resectable tumor, even in T1N2 disease.

Adult↗
PubMed1991

Lichen sclerosus et atrophicus, morphea, and coexistence of both diseases. Histological studies using lectins.

Histological studies using three lectins, lens culinaris agglutinin, soybean agglutinin, and Ulex europaeus agglutinin-I, were carried out in a case of coexistent lichen sclerosus et atrophicus and morphea, five cases of morphea, and two cases of lichen sclerosus et atrophicus. The lectin staining patterns of the formaldehyde-fixed epidermis of patients with morphea were not different from those of normal epidermis, but epidermis of patients with lichen sclerosus et atrophicus showed different staining patterns. Lens culinaris agglutinin stained the basal and the spinous layers of the normal epidermis and that of patients with morphea but stained only the basal cells of the epidermis from patients with lichen sclerosus et atrophicus; epidermal Ulex europaeus agglutinin binding was observed only in the cases of lichen sclerosus et atrophicus. Moreover, in the patient with coexistent diseases, the morphea lesion showed the staining profiles of morphea and the lichen sclerosus et atrophicus lesion showed the staining patterns of lichen sclerosus et atrophicus, respectively.

Adolescent↗
PubMed1991

[A case of inflammatory pseudotumor of the lung that extended to involve the mediastinum].

A 17-year-old woman was referred to our hospital because of cough and fever. The chest X-ray films revealed an anterior mediastinal mass shadow. Steroid drugs and antibiotics were administered and the shadow diminished slightly. To confirm diagnosis, open thoracotomy was performed. The tumor was extended to the mediastinum, thymus and heart as well as the right middle lobe and right lower lobe. Microscopic findings of the resected tumor showed proliferation of histiocytes with infiltration by inflammatory cells, lymphocytes and fibrous tissue.

Adolescent↗
PubMed1991

[Postoperative irradiation of cervical carcinoma without lymph nodal involvement or parametrial invasion].

Radical hysterectomy for uterine cervical cancer was performed on 469 patients without metastasis in either the parametrium (P) or pelvic node (N). In 225 of the patients, the tumor had invaded deeply, with the remaining non-invaded myometrium being less than 5 mm deep. In 54 of the patients, the tumor had invaded the vagina. These two sets of cases (postoperative advanced Ib and IIa) were the subjects of the present examination. Eighty-three of the 225 patients were given postoperative irradiation, and 142 were not. The 5-year survival rates were 84% (70/83) in patients with irradiation and 92% (131/142) in those without irradiation (p less than 0.10). Eight patients with irradiation died of causes which might be attributable to the irradiation. The rates of recurrence were similar in both groups (8.4%, 7/83 vs 9.2%, 3/142). However, there was a significant difference (p less than 0.025) between these two groups (1.2%, 1/83 vs 2.8%, 4/142) in the recurrence rate when only the areas of irradiation were considered. In the 54 patients with IIa cancer, the 5-year survival rates and the rates of recurrence were not significantly different for those patients with irradiation from those without irradiation. Therefore, these results indicate that postoperative irradiation may not be essential for P(-)N(-) patients.

Female↗
PubMed1990

Inhibition of human brain aromatic L-amino acid decarboxylase by cooked food-derived 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and other heterocyclic amines.

A carcinogenic, food-derived heterocyclic amine, 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), was found to inhibit aromatic L-amino acid decarboxylase isolated from human brainstem. Trp-P-2 inhibited the enzyme activity toward L-DOPA more markedly than that toward 5-hydroxytryptophan. The inhibition was competitive to a cofactor of the enzyme, pyridoxal-5-phosphate, and the Ki value of Trp-P-2 was 163 microM. The enzyme activity could be fully recovered after removal of Trp-P-2 by gel filtration, which indicates that the inhibition was reversible. Among a series of heterocyclic amines examined for their effects on the activity toward L-DOPA, Trp-P-2 was the most potent inhibitor, followed by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, then Trp-P-1. Another heterocyclic amine, 2-amino-3-methyl-9H-pyrido[2,3-b]indole also inhibited the enzyme. The inhibition of the decarboxylase activity by these heterocyclic amines may affect the catecholamine metabolism in human brain.

5-Hydroxytryptophan↗
PubMed1990

Effect of glucocorticoid on epidermal growth factor receptor in human salivary gland adenocarcinoma cell line HSG.

Human salivary gland adenocarcinoma (HSG) cells treated with 10(-6) M triamcinolone acetonide for 48 h exhibited a 1.7- to 2.0-fold increase in [125I]human epidermal growth factor (hEGF) binding capacity as compared with untreated HSG cells. Scatchard analysis of [125I]EGF binding data revealed that the number of binding sites was 83,700 (+/- 29,200) receptors/cell in untreated cells and 160,500 (+/- 35,500) receptors/cell in treated cells. No substantial change in receptor affinity was detected. The dissociation constant of the EGF receptor was 0.78 (+/- 0.26).10(-9) M for untreated cells, whereas it was 0.93 (+/- 0.31).10(-9)M for treated cells. The triamcinolone acetonide-induced increase in [125I]EGF binding capacity was dose-dependent between 10(-9) and 10(-6)M, and maximal binding was observed at 10(-6)M. EGF receptors on HSG cells were affinity-labeled with [125I]EGF by use of the cross-linking reagent disuccinimidyl suberate (DSS). The cross-linked [125I]EGF was 3-4% of the total [125I]EGF bound to HSG cells. The affinity-labeled EGF receptor was detected as a specific 170 kDa band in the autoradiograph after SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Densitometric analysis revealed that triamcinolone acetonide amplified the intensity of this band 2.0-fold over that of the band of untreated cells. EGF receptor synthesis was also measured by immunoprecipitation of [3H]leucine-labeled EGF receptor protein with anti-hEGF receptor monoclonal antibody. Receptor synthesis was increased 1.7- to 1.8-fold when HSG cells were treated with 10(-8)-10(-6)M triamcinolone acetonide for 48 h. When the immunoprecipitated, [35S]methionine-pulse-labeled EGF receptor was analyzed by SDS-PAGE and fluorography, the newly synthesized EGF receptor was detected at the position of 170 kDa; and treatment of HSG cells with triamcinolone acetonide resulted in a 2.0-fold amplification of this 170 kDa band. There was no significant difference in turnover rate of EGF receptor between treated and untreated HSG cells. These results demonstrate that the triamcinolone acetonide-induced increase in [125I]EGF binding capacity is due to the increased synthesis of EGF receptor protein in HSG cells.

Adenocarcinoma↗
PubMed1990

Association of autoimmune hepatitis with HLA-Bw54 and DR4 in Japanese patients.

Human leukocyte antigen-D region-related alleles (human leukocyte antigen DR and DQ) and human leukocyte antigen class I alleles were typed serologically in 31 Japanese patients with autoimmune hepatitis. These patients had increased serum levels of AST and IgG, high titers of autoantibodies, no history of blood transfusion and were negative for HBsAg and antibodies to HBc. Three hundred eighty-six healthy subjects and 30 patients with cryptogenic chronic hepatitis served as control groups. The frequency of DR4 was significantly higher in autoimmune hepatitis patients (90.3%) than in healthy subjects (38.6%) and in cryptogenic chronic hepatitis patients (30%). The frequency of Bw54 was significantly higher in autoimmune hepatitis patients (45.2%) than in healthy subjects (10.9%). The risk to DR4-positive subjects for autoimmune hepatitis was 14.8 relative to healthy subjects. Two of 31 patients (6.5%) with autoimmune hepatitis were positive for antibody to hepatitis C virus; both clearly satisfied criteria for autoimmune hepatitis and both had Bw54 and DR4. This study revealed a highly significant association of autoimmune hepatitis with human leukocyte antigen Bw54 and DR4 in Japanese patients. Among the DR4-positive patients with autoimmune hepatitis, no significant differences were seen between those positive or negative for Bw54 with regard to clinical or laboratory data, relapse of disease or efficacy of prednisolone. Thus human leukocyte antigen class II alleles contribute to susceptibility and resistance to autoimmune hepatitis in Japanese patients, with distinct racial differences from those in white patients.

Adult↗