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Biomedical subjects

M Ota

Publications and source records attributed to M Ota.

At least 163 records · Page 9Linked to original sources
PubMed1996

The production of arthritis in beagles by an immunological reaction to bovine serum albumin.

Arthritis was produced in beagles by the immunological reaction to bovine serum albumin (BSA). Dogs immunized with BSA showed the development of delayed type-hypersensitivity response to BSA and the significant increase in the titer of serum anti-BSA antibodies. The development of arthritis and the increase in a number of nucleated cells in synovial fluid were observed by the injection with BSA into the knee joints of immunized dogs. The synovial membrane of BSA-injected joints revealed a remarkable villous hyperplasia of membrane, and an infiltration of lymphocytes and plasma cells around vessels, resulting in a lymphoid nodule-like formation. The depositions of IgG and C3 on the surface of the synovial membrane were also observed in BSA-injected joints. Histopathological and immunopathological findings indicated that the immune response to BSA in the knee joints could induce a rheumatoid arthritis like chronic synovitis in dogs.

Animals↗
PubMed1996

The allele frequency distribution at VNTR locus D17S5 (YNZ22) in a Japanese population sample.

The allele frequencies for the YNZ22 locus were determined in a Japanese population sample (n = 164) using the polymerase chain reaction (PCR). We observed 10 alleles and 39 genotypes. Allele distributions in our data showed a different pattern from those reported in the literature for European Caucasians. No deviation from Hardy-Weinberg equilibrium was found. The observed heterozygosity was 83.5%. In Japan the YNZ22 is one of useful genetic markers for paternity testing and identify testing, with a chance of exclusion (CE) value of 68% and a power of discrimination (PD) value of 89%.

Alleles↗
PubMed1996

Proliferative signal transduction by epidermal growth factor (EGF) in the human salivary gland adenocarcinoma (HSG) cell line.

We examined the proliferative signal transduction by EGF in HSG-AZA 3, a subclone of HSG cell line. The treatment of cells with EGF resulted in an increase in [3H]thymidine incorporation into DNA depending upon EGF concentrations. In addition, the nuclear proto-oncogene c-fos was rapidly induced by EGF. Moreover, EGF induced transient expression of EGF receptor mRNA followed by the de novo synthesis of EGF receptor protein. On the other hand, treatment of the cells with EGF occurred phosphorylation by tyrosine kinase comprised in the EGF receptor, autophosphorylation, followed by activation of MAP kinase. These results indicate that the proliferative response to EGF is modulated by the phosphorylation cascade mediating EGF receptor-associated tyrosine kinase and MAP kinase, and transient activation of c-fos protein is implicated in the cell proliferation.

Adenocarcinoma↗
PubMed1996

Allele distribution of a VNTR polymorphism at D4S43 locus in the Japanese population.

Allele frequencies for the VNTR locus D4S43 were determined in a Japanese population sample by the polymerase chain reaction. Nine different alleles containing 1-15 repeats of the basic 14 bp unit were observed in 156 unrelated Japanese. The most common allele was one repeat unit (62.82%), and the next common alleles were those with 11 (14.42%) and 7 repeat units (12.50%). We estimated that D4S43 locus has a heterozygosity index of 0.56, a mean exclusion chance of 0.32, a discrimination rate of 0.76, and a polymorphic information content of 0.52. No evidence of significant deviations from the Hardy-Weinberg equillibrium was found in the Japanese population data.

Alleles↗
PubMed1996

Automated DNA typing of ACTBP2: a comparison of allelic ladder with GS 2500 as internal marker.

A comparison was made between the size values of the alleles measured by the internal size marker of Genescan (GS 2500) and the size values measured by an allelic ladder constructed by our laboratory in the application of Genescan software for the typing of the ACTBP2 system. The measurement by GS 2500 showed a greater than 2 bp divergence (SD = 0.893) while the measurement by the allelic ladder showed only 0.1 bp divergence (SD = 0.008). Thus in genotyping of ACTBP2 by Genescan software, the method presented here of using the allelic ladder as the size marker instead of GS 2500 is easier and more reliable.

Alleles↗
PubMed1996

[Proliferation and differentiation of human salivary gland adenocarcinoma cell line HSG].

The adenocarcinoma cell line derived from an intercalated ductal epithelium of a human salivary gland (HSG) proliferates autonomously mediated by an epidermal growth factor-(EGF)-like molecule with a molecular weight of 46 kDa and an EGF receptor (EGFR). The c-erbB2 protein, a member of EGFR family was also expressed in HSG cells and was involved in the growth signal pathway of HSG cells as well as EGFR. The autocrine growth is regulated by glucocorticoid and retinoic acid (RA) via their receptors. Retinoic acid receptor (RAR) of HSG cells revealed a transcriptional activity in vivo, and the heterodimerization between RAR and 9-cis retinoic acid receptor (RXR) is requisite for the binding with a specific DNA element termed RA response element in vitro. RXR alpha and RXR beta were cloned from HSG cells, and these RXRs, together with RAR, seemed to play a physiological role in RA signaling in vivo.

Adenocarcinoma↗
PubMed1995

Mechanism of dimer formation of the 90-kDa heat-shock protein.

This study describes the mechanism of homodimer formation of the 90-kDa heat-shock protein (HSP90). In eukaryotic cells, there are two HSP90 isoforms, alpha and beta, encoded by two separate genes. HSP90 alpha exists predominantly as a homodimer, HSP90 beta mainly as a monomer. Analysis by native PAGE revealed that bacterially expressed HSP90 alpha fused to glutathione S-transferase (GST) existed as a high-molecular-mass oligomer, and was converted to a homodimer following removal of the fusion enzyme by thrombin cleavage. A deletion mutant, HSP90 alpha D44-603, formed a monomer and an N-terminal truncated mutant, HSP90 alpha 533-732, existed as a dimer, indicating that the dimer-forming ability resides somewhere in the C-terminal 200 amino acids. Limited proteolysis of the C-terminal 200 amino acids of HSP90 alpha with chymotrypsin produced the C-terminal 16-kDa fragment (Met628/Ala629-Asp732) and its adjacent more N-terminal 13-kDa fragment (Val542-Tyr627/Met628). Size-exclusion HPLC and two-dimensional PAGE analyses demonstrated that these two chymotryptic fragments bound each other. The C-terminal 198 amino acids as well as the full-length form of HSP90 beta revealed a lower dimer-forming activity than HSP90 alpha. Expression of the chimeric proteins at the C-terminal 198 amino acids of the alpha and beta isoforms further indicated that the 16 amino acid substitutions locating between amino acids 561 and 685 account for the impeded dimerization of HSP90 beta. A leucine zipper motif (Met402-Leu423) was unlikely to be involved in the dimer formation. Taken together, these results indicate that the dimeric structure of HSP90 alpha is mediated by the C-terminal 191 amino acids and consists of duplicate interactions of the C-terminal region (Met628/Ala629-Asp732) of one subunit and the adjacent more N-terminal region (Val542-Try627/Met628) of the other subunit.

Amino Acid Sequence↗
PubMed1995

Potent inhibitors of acyl-CoA:cholesterol acyltransferase. Structure-activity relationships of novel N-(4-oxochroman-8-yl)amides.

Novel N-(4-oxochroman-8-yl)amide derivatives 1 were synthesized and tested for their ability to inhibit rabbit small intestinal ACAT (acyl-CoA:cholesterol acyltransferase) in vitro and to lower serum total cholesterol in cholesterol-fed rats in vivo. Among the synthesized compounds, N-(7-alkoxy-4-oxochroman-8-yl)amide derivatives showed potent ACAT inhibitory activity both in vitro and in vivo. The structure-activity relationships of these N-(4-oxochroman-8-yl)amides and related compounds are discussed on the basis of these two assays. The carbonyl group at position 4 of the 4-chromanone was essential for potent ACAT inhibitory activity. N-(Chromon-8-yl) derivatives were less potent than N-(4-oxochroman-8-yl) derivatives. An alkoxy group at position 7 of the 4-chromanone moiety was important for potent ACAT inhibitory activity. In the N-(7-alkoxy-4-oxochroman-8-yl)amide derivatives, another necessary factor to elicit the potent ACAT inhibitory activity was lipophilicity of the molecules. The highly lipophilic acid amides N-(7-methoxy-4-oxochroman-8-yl)-2,2-dimethyldodecanamide (35) and 4-[[6-(4-chlorophenoxy)hexyl]oxy]-N-(7-methoxy-4-oxochroman-8- yl)benzamide (63) showed potent activity. Introduction of a highly lipophilic alkoxy group at position 7 of the 4-chromanone moiety instead of methoxy group also resulted in potent activity. In this case, highest inhibitory activity was obtained by N-[7-(decyloxy)-4-oxochroman-8-yl]-2,2-dimethylpropanamid e (65). The most potent compound, N-(7-methoxy-4-oxochroman-8-yl)-2,2-dimethyldodecanamide (35, TEI-6522), showed significant ACAT inhibitory activity (rabbit small intestine IC50 = 13 nM, rabbit liver IC50 = 16 nM), foam cell formation inhibitory activity (rat peritoneal macrophage IC50 = 160 nM), and extremely potent serum cholesterol-lowering activity in cholesterol-fed rats (61% at a dose of 0.1 mg/kg/day po).

Animals↗
PubMed1995

Desk-top analysis of the structural stability of various point mutations introduced into ribonuclease H.

The structural stability of Escherichia coli ribonuclease HI mutants was analyzed by a pseudo-energy potential developed for evaluating structure-sequence compatibility. From the structure profile, the energy changes of the folding of mutant proteins relative to that of the wild-type, which correspond to the changes of free energy differences, were estimated. They are weakly but significantly correlated with the experimentally determined changes in the melting temperature between the mutant proteins and the wild-type. The correlation coefficient between the experimental data and the computation, estimated for all the known data (96 point mutations) and for the buried site data (32 point mutations), are -0.51 and -0.68, respectively. Experimentally known mechanisms to increase the structural stability are explained by the method: the main contributor to the stability in mutations of Val74 to either Ile or Leu is the side-chain packing energy, and that of Lys95 to Gly is the local conformational energy. This analysis is easy to do on a desk-top computer, and allows one to consider all the sites of possible candidates for point mutations. From the profile, new promising sites to increase the structural stability are suggested.

Computer Simulation↗
PubMed1995

Immunohistochemical study on collagenous proteins and biophysical analysis of crystals in extraskeletal chondroma.

The immunohistological distribution of collagen types I, II, III, and VI in five cases of extraskeletal chondroma was examined and compared with that in six cases of enchondroma. In addition, the composition of crystals deposited in three cases of extraskeletal chondroma were biophysically analyzed with special attention to the relationship between the collagen types of the matrix and the crystal deposition. In extraskeletal chondroma, immunoreactivity of type II collagen in the extracellular matrix and type VI collagen in the pericellular area, which were strongly and diffusely recognized in the normal hyaline cartilage and enchondroma, was diminished. Instead, additional types of collagen, types I and III, were demonstrated in the matrix. Electron roentgenographic microanalysis and infrared light spectroscopic analysis revealed that calcium pyrophosphate dihydrate (CPPD) was included in the crystals of extraskeletal chondroma. CPPD crystals were observed in/around collagen types I and III. The possible relationship between the difference of collagen composition in the matrix and the CPPD crystal deposition is discussed.

Adult↗
PubMed1995

Proteus syndrome with renal involvement.

We report on a case of an 11 year old girl with Proteus syndrome involving both kidneys morphologically and functionally. The patient had hemihypertrophy, scoliosis, overgrowth of lower extremities, partial macrodactyly, subcutaneous lipoma, and pigmented nevi compatible with the Proteus syndrome. She also had overgrowth of the right kidney with mildly impaired function and a small left kidney with severe dysfunction. Morphological involvement of visceral organs has previously been described; however, deteriorating renal function has not previously been reported in this syndrome.

Child↗
PubMed1995

Recurrent reversible rhabdomyolysis associated with hyperthermia and status epilepticus.

A 6-year-old boy developed rhabdomyolysis following hyperthermia and status epilepticus with a diagnosis of severe myoclonic epilepsy of infancy. At 2 and 3 years of age, he had similar episodes. Each time he recovered completely in 3-4 weeks with conservative management, in spite of renal insufficiency and marked liver dysfunction. Several cases of recurrent myoglobinuria after intense exercise of generalized tonic-clonic convulsions were reported to have genetic errors of carbohydrate or lipid metabolism of muscle. In our patient, however, the activity of these enzymes was found to be normal. This indicates that status epilepticus may cause recurrent rhabdomyolysis in subjects with normal glycolytic and lipolytic enzyme activity.

Acute Kidney Injury↗
PubMed1995

Location of the disulfide bonds of the sweetness-suppressing polypeptide gurmarin.

The sweetness-suppressing polypeptide gurmarin has been isolated from the leaves of Gymnema sylvestre and consists of 35 amino acid residues including three intramolecular disulfide bonds. The primary structure has already been determined. The positions of the disulfide bonds were located, by a combination of mass spectrometric analysis and sequencing of cystine-containing peptides obtained by thermolysin-catalyzed hydrolysis of gurmarin, to be at Cys3-Cys18, Cys10-Cys23, and Cys17-Cys33.

Amino Acid Sequence↗
PubMed1995

Reduction of androgen receptor mRNA concentration by testosterone in mouse submandibular gland.

In this study, we examine the effect of testosterone on the steady-state concentration of androgen receptor (AR) mRNA of mouse submandibular gland. Northern blot analysis showed the expression of an AR-specific 10-kb transcript in the submandibular glands of both sexes. Quantitative analysis was done by means of reverse transcription-polymerase chain reaction (RT-PCR) with a non-radioactive label of digoxigenin. The RT-PCR demonstrated that the steady-state of AR mRNA concentration was less in males than in females. Moreover, AR mRNA increased in the castrated male mice, while the administration of testosterone reduced the AR mRNA in female mice. In conclusion, the amount of AR mRNA in mouse submandibular gland is reduced by androgen.

Animals↗