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Biomedical subjects

S Ohta

Publications and source records attributed to S Ohta.

At least 595 records · Page 33Linked to original sources
PubMed1992

[Drinking-related changes in dietary intake in 2165 male adults--with special reference to carbohydrate, protein and fat].

A food intake-frequency survey using a 7-day weighted inventory questionnaire was conducted among 2165 healthy men aged from 18 to 85 living in Nagano Prefecture. The effect of ethanol consumption on the intake of 12 different groups of food (cereals, potatoes, sugar, confectioneries, fruit, vegetables, soybean and its products, eggs, milk and dairy products, fish, meat, and oils), on the intake of macronutrients (carbohydrate, protein and fat), on the total energy intake including and excluding energy from ethanol, and on the energy percentage from carbohydrate, protein and fat, were analyzed. As ethanol consumption increased, the intake of cereals and confectioneries was found to markedly decrease, and that of potatoes, sugar, fruit, vegetables, milk and dairy products, and oils to decrease to a lesser extent. In contrast, the intake of meat increased with increasing ethanol consumption. The intake of carbohydrate, vegetable protein and fat decreased with increase in ethanol consumption in the following order: carbohydrate greater than vegetable protein = vegetable fat. As ethanol consumption increased, total energy intake including energy from ethanol increased, but the energy excluding ethanol decreased. The energy percentage contributed by carbohydrate, vegetable protein, and vegetable and animal fat decreased with increase of ethanol consumption: the extent of the decrease was most prominent in energy from carbohydrate, followed by vegetable fat, animal fat and vegetable protein in decreasing order. These results suggest that people have a tendency to consume less carbohydrate, especially cereals, when increasing ethanol consumption.

Adult↗
PubMed1992

[Molecular biological study on the overexpression of c-myc gene in uterine cervical carcinomas].

The expression of mRNA for c-myc gene was investigated in 30 cases of human uterine cervical carcinoma by Northern blot hybridization, and c-myc gene amplification was also examined by Slot blot hybridization. Overexpression of c-myc gene was detected in one (7.7%) of 13 cases of carcinoma in situ (stage 0), one (10.0%) of 10 stage I and 4 (57.1%) of 7 stage II uterine carcinoma, and c-myc gene amplification was detected in 2 cases (6.7%) in which c-myc gene overexpression was also found. The patient whose c-myc mRNA level was more than 10 times as high as in normal uterine cervical tissue relapsed and died within 2 years after the first treatment. Our results suggest that the overexpression of c-myc gene occurred more frequently in advanced than in early uterine cervical carcinoma and that it might be useful in prognosing cervical cancer.

Adenocarcinoma↗
PubMed1991

Introduction of disease-related mitochondrial DNA deletions into HeLa cells lacking mitochondrial DNA results in mitochondrial dysfunction.

Mutant mitochondrial DNA with large-scale deletions (delta-mtDNA) has been frequently observed in patients with chronic progressive external ophthalmoplegia (CPEO), a subgroup of the mitochondrial encephalomyopathies. To exclude involvement of the nuclear genome in expression of the mitochondrial dysfunction characteristic of CPEO, we introduced the mtDNA of a CPEO patient into clonal mtDNA-less HeLa cells and isolated cybrid clones. Quantitation of delta-mtDNA in the cybrids revealed that delta-mtDNA was selectively propagated with higher levels of delta-mtDNA correlating with slower cellular growth rate. In these cybrid clones, translational complementation of the missing tRNAs occurred only when delta-mtDNA was less than 60% of the total mtDNA, whereas accumulation of delta-mtDNA to greater than 60% resulted in progressive inhibition of overall mitochondrial translation as well as reduction of cytochrome c oxidase activity throughout the organelle population. Because these cybrids shared the same nuclear background as HeLa cells, these results suggest that large-scale deletion mutations of mtDNA alone are sufficient for the mitochondrial dysfunction characteristic of CPEO.

Adolescent↗
PubMed1991

Amphetamine-antagonistic properties of 4-phenyl-1,2,3,4- tetrahydroisoquinoline: inhibition of spinal reflex-enhancing effects of methamphetamine, phenylethylamine and nomifensine.

The antagonistic effects of 4-phenyl-1,2,3,4-tetrahydroisoquinoline (4PTIQ) against S(+)-methamphetamine, phenylethylamine and nomifensine were studied by measurement of spinal monosynaptic reflex potential (MSR). S(+)-Methamphetamine, phenylethylamine and nomifensine enhanced the amplitude of MSR in C1-spinalized rats through release of noradrenaline from the terminals of descending fibers and consequent activation of alpha 1-adrenoceptors. Although 4PTIQ alone did not change the amplitude of the MSR, 4PTIQ inhibited the enhancement of MSR induced by S(+)-methamphetamine and related compounds. The MSR of rats with an intact spinal cord was enhanced by conditioning stimulation of the ipsilateral locus ceruleus. The MSR enhancement produced by the stimulation was blocked by prazosin but unaffected by 4PTIQ, showing that 4PTIQ does not have an alpha 1-blocking action. These results suggest that the antagonistic effects of 4PTIQ on MSR enhancement by S(+)-methamphetamine, phenylethylamine and nomifensine are due to its blocking of noradrenaline release produced by these amphetamine-like agents.

Amphetamine↗
PubMed1991

Analysis of the survival of mature human eosinophils: interleukin-5 prevents apoptosis in mature human eosinophils.

We and other groups have previously shown that interleukin-5 (IL-5) maintained the viability of mature eosinophils in an in vitro liquid culture system. Mature eosinophils did not proliferate but their survival was maintained in the presence of IL-5. Using this culture system, we investigated the mechanism of IL-5-mediated survival. In the absence of human IL-5 (hIL-5) mature eosinophils succumbed after 4 days, while in the presence of hIL-5 they survived up to 10 days. When DNA extracts of cultured eosinophils were analyzed on an agar gel electrophoresis, marked DNA fragmentation was observed in the absence of hIL-5, while no significant DNA fragmentation was observed in the culture with hIL-5 for 48 hours. The DNA fragmentation appeared as early as 6 to 12 hours after hIL-5 deprivation. Concomitantly, IL-5 stimulated total RNA and protein synthesis, but did not induce DNA synthesis in mature eosinophils. Because cycloheximide or actinomycin D impeded the protection of apoptosis by hIL-5, some new RNA and protein synthesis appeared to be required in this phenomena. These findings indicate that IL-5 maintains survival of mature eosinophils with induction of new RNA and protein synthesis, thus leading to the inhibition of apoptosis.

Cell Death↗
PubMed1991

Purification and molecular cloning of succinyltransferase of the rat alpha-ketoglutarate dehydrogenase complex. Absence of a sequence motif of the putative E3 and/or E1 binding site.

Full-length cDNA clones for succinyltransferase of the rat alpha-ketoglutarate dehydrogenase complex were isolated from rat heart cDNA libraries in lambda gt11. The cDNA clones were identified as those for rat succinyltransferase by the identity of their predicted amino acid sequence with the NH2-terminal amino acid sequence of rat succinyltransferase determined by protein chemical analysis and the known amino acid sequence of bovine succinyltransferase. The clone with the longest cDNA consisted of 2747 base pairs and coded for a leader peptide of 56 amino acid residues and a mature protein of 386 amino acid residues. The primary structure of rat succinyltransferase showed close similarity to Escherichia coli and Azotobacter vinelandii succinyltransferases, in the COOH-terminal part forming the lipoyl-binding domain and the NH2-terminal part forming the inner core-catalytic domain. However, the rat succinyltransferase did not contain a sequence motif that has been found as an E3- and/or E1-binding site in the dihydrolipoamide acyltransferases of three alpha-ketoacid dehydrogenase complexes (Hummel, K. B., Litwer, S., Bradford, A. P., Aitken, A., Danner, D. J., and Yeaman, S. J. (1988) J. Biol. Chem. 263, 6165-6168, Reed, L. J., and Hackert, M. L. (1990) J. Biol. Chem. 265, 8971-8974). The absence of this sequence was confirmed by direct sequencing of the polymerase chain reaction product of rat heart mRNA and by computer analysis. These results show that the rat succinyltransferase does not have the sequence motif of the putative E3- and/or E1-binding site.

Acyltransferases↗
PubMed1991

Small-angle X-ray scattering studies of Mg.AT(D)P-induced hexamer to dimer dissociation in the reconstituted alpha 3 beta 3 complex of ATP synthase from thermophilic bacterium PS3.

The alpha 3 beta 3 complex of ATP synthase obtained from a thermophilic bacterium PS3 was isolated and found to show the ATPase activity (Kagawa, Y., Ohta, S., and Otawara-Hamamoto, Y. (1989) FEBS Lett. 249, 67-69). The structure and the nucleotide binding effects of the alpha 3 beta 3 complex were investigated by means of small-angle x-ray scattering and high performance liquid chromatography. The scattering profile from the alpha 3 beta 3 complex was explained with a model in which the complex is made of an ellipsoid of revolution with the axes of 121.8, 121.8, and 72.0 A having an elliptical hollow cavity with the axes of 35.4, 35.4, and 72.0 A. By the addition of Mg.AT(D)P, significant changes in the scattering profile were observed, in which the radius of gyration decreased from 44 to 35 A. This change was found by gel filtration to be caused by the dissociation reaction from the alpha 3 beta 3 hexamer to the alpha beta dimer. The dissociation of the alpha 3 beta 3 complex was not induced by unhydrolyzable ATP analogue, nor by Pi, Mg2+, and Pi + Mg2+. The structure of the dimer was well explained by the triaxial ellipsoidal model with the axes of 105.2, 39.4, and 108.2 A. The dissociation into the dimer is considered to be related to the ATPase activity because the AT(D)P-induced dissociation is observed only in the presence of Mg2+ ions.

Adenosine Diphosphate↗
PubMed1991

Fracture healing induces expression of the proto-oncogene c-fos in vivo. Possible involvement of the Fos protein in osteoblastic differentiation.

Here we report marked in vivo expression of the c-fos gene in the external soft callus (ESC) and periosteal hard callus (PHC) at the fracture site of adult rat tibia. Northern-blot analysis showed that the ESC expressed a high level of c-fos mRNA from post-fracture day 10 to day 28, the time when endochondral ossification progressed, and that the ossifying PHC also expressed c-fos mRNA. This c-fos expression was followed by sequential expression of the genes for alkaline phosphatase, osteopontin and osteocalcin, which are osteoblastic markers. Immunohistochemical analysis showed that the c-Fos protein was predominantly located in osteoblasts in the ossifying calluses.

Alkaline Phosphatase↗
PubMed1991

The alpha-ketoacid dehydrogenase complexes. Sequence similarity of rat pyruvate dehydrogenase with Escherichia coli and Azotobacter vinelandii alpha-ketoglutarate dehydrogenase.

The pyruvate dehydrogenase complex and the alpha-ketoglutarate dehydrogenase complex are multienzyme complexes consisting of three different enzymes. No significant similarity has been reported among the dehydrogenases which are component enzymes of these complexes, despite the presence of homology among the other component enzymes. Here we isolated cDNAs for the alpha and beta subunits of rat pyruvate dehydrogenase and they exhibited a significant similarity of the amino acid sequences among rat pyruvate dehydrogenase, 2-oxoisovalerate dehydrogenase (which is a dehydrogenase component of branched chain alpha-ketoacid dehydrogenase complex) and alpha-ketoglutarate dehydrogenase, suggesting that they have been derived from a common ancestral dehydrogenase. Our results suggested that the alpha and beta subunits of the pyruvate and 2-oxoisovalerate dehydrogenases have been derived by the cleavage of the alpha-ketoglutarate dehydrogenase. However, we could not find significant homology between rat pyruvate dehydrogenase and Gram-negative bacterial pyruvate dehydrogenase.

Amino Acid Sequence↗
PubMed1991

Effects of oxygen on the relative photodissociability of cytochrome P-450.CO complex in rat liver microsomes.

Flash photolysis of cytochrome P-450 in phenobarbital-induced rat liver microsomes was examined by observing the decay of absorbance change, A(t), at 450 nm after photolysis of the heme.CO complex by a depolarized laser flash. The relative photodissociability, A(0)/Ab, is significantly decreased upon an increase in oxygen concentration. A(0)/Ab is 96%, 86%, and 51% at oxygen concentrations of 90, 115, and 155 microM when compared with A(0)/Ab at 0 microM O2. In the presence of aminopyrine, the oxygen-dependent decrease in the relative photodissociability was enhanced about 2 times. The rate of CO recombination with cytochrome P-450 was decreased by increasing O2 concentration. By going from 0 to 155 microM O2, about 17% decrease and 58% decrease in the recombination rate were observed in the absence and presence of aminopyrine, respectively. In the absence of CO, no absorbance change A(t) at 450 nm was observed even at 155 microM O2, excluding a possible contribution of P-450.O2. The present observation leads to the speculation that oxygen molecules around the heme.CO complex affect the electronic state of the heme, resulting in an increase in Fe-CO bond strength.

Aminopyrine↗
PubMed1991

The lectin wheat germ agglutinin induces rapid protein-tyrosine phosphorylation in human platelets.

In response to wheat germ agglutinin (WGA), platelet aggregation and stimulation of protein-tyrosine phosphorylation were observed in a dose dependent manner. These reactions were completely inhibited by coexistence of N-acetyl-D-glucosamine with WGA. Upon stimulation by this agonist, protein-tyrosine phosphorylation of seven bands with molecular masses of 140-, 130-, 80-, 76-, 53-, 38- and 35-kDa proteins was observed by immunoblot. These protein-tyrosine phosphorylations were divided into three groups by kinetics. Considering the previous report from our laboratory that thrombin and collagen induced tyrosine phosphorylation in 135-, 124- and 76-kDa proteins (Nakamura, S. and Yamamura, H. (1989) J. Biol. Chem. 264, 7089-7091.), there may be another signal transduction pathway in tyrosine phosphorylation of human platelets.

Blood Platelets↗
PubMed1991

Scanning electron microscopy of the capillary loops in the dermal papillae of the hand in primates, including man.

The microvasculature of the skin of the hand in primates, including man, was examined by means of scanning electron microscopy of corrosion casts. In this study, the microvascular patterns and structures in different areas of the hand, and the changes in vascular patterns that occur with age, have been described. The typical structure of the capillary loops in the hand can be observed in the ball of the finger of the young adult monkey. The capillary loops were formed out of not just one capillary vessel, but two or three vessels. Each capillary vessel arose and divided into several branches at the papillae, and these became descending limbs. After the loop passed a hairpin turn, the descending limbs were 1.5 times larger than the ascending limbs in the intrapapillary portion, and they became extrapapillary venules. The descending limbs connected with the postcapillary venules in the postpapillary portion and with the horizontal network. The postcapillary venules fused with each other to form the primary and secondary venous arcades. The secondary venous arcades anastomosed with each other and flowed into the subpapillary venules, which run along the dermal furrow in the fingerprint. Changes in vascular patterns with age could be observed. In the infant fingerprint, the vascular systems had not yet differentiated, especially the venous system in the dermis. In the old adult finger, the capillary loops presented complicated features deviating due to aging.

Aged↗
PubMed1991

High-level expression of a sweet potato sporamin gene promoter: beta-glucuronidase (GUS) fusion gene in the stems of transgenic tobacco plants is conferred by multiple cell type-specific regulatory elements.

Genes coding for sporamin, the most abundant protein of the tuberous root of the sweet potato, are expressed at a high levels in the stems of plantlets cultured axenically on sucrose-containing medium. Their expression is also induced in leaf-petiole explants by high concentrations of sucrose. A fusion gene comprising of the 1 kb 5' upstream region of the gSPO-A1 gene coding for the A-type sporamin and the coding sequence of bacterial beta-glucuronidase (GUS) was introduced into the tobacco genome by Agrobacterium-mediated transformation. Transgenic tobacco plants cultured axenically on sucrose-containing medium expressed GUS activity predominantly in their stems. Histochemical examination of GUS activity using a chromogenic substrate showed a distinct spatial pattern of GUS staining in the stem. Strong GUS activity was detected in the internal phloem of the vascular system and at the node, especially at the base of the axillary bud. Relatively weaker GUS activity was also detected in pith parenchyma. A 5' deletion of the promoter to nucleotide -305, relative to the transcription start site, did not alter significantly the level of GUS activity or the spatial pattern of GUS staining in the stem. However, further deletions to -237 and -192 resulted in a decrease in the level of GUS activity in the stem that occurred simultaneously with the loss of GUS staining in both the internal phloem and at the base of the axillary bud. However, plants with these deletion constructs still exhibited the predominant expression pattern of GUS activity in the stem and GUS staining in the pith parenchyma cells. Deletion to -94 completely abolished the expression of GUS activity. These results indicate that a sequence between -305 and -237 contains a cis-regulatory element(s) that is required for expression of the GUS reporter gene in both the internal phloem and at the base of the axillary bud, while a sequence between -192 and -94 contains a cis-acting element(s) that is required for expression in pith parenchyma cells.

Base Sequence↗
PubMed1991

The effect of a dihydropyridine calcium antagonist (isradipine) on selective neuronal necrosis.

The experiments were designed to test the possibility that calcium influx into neurons via voltage sensitive calcium channels (VSCCs) contribute to brain damage in two conditions in which any amelioration of neuronal necrosis may be assumed not to occur through an improvement of blood flow, viz., hypoglycemic coma and brief transient ischemia. Hypoglycemic coma is thought to lead to neuronal necrosis by release of glutamate and cellular influx of calcium during the insult, while damage due to brief transient ischemia may, at least in part, result from increased calcium cycling across cell membranes in the postinsult period. The insults were delivered to anesthetized rats, and the localization and density of neuronal necrosis were evaluated by histopathology following 1 week of recovery. One dihydropyridine calcium antagonist (isradipine), given in doses which have been reported to ameliorate ischemic damage due to stroke, failed to reduce damage incurred by 30 min of hypoglycemic coma, or 15 min of transient forebrain ischemia. Provided that it can be assumed that isradipine in the doses employed reduced calcium influx via VSCCs, the results support the notion that calcium influx through VSCCs plays only a minor pathogenetic role in global/forebrain ischemia or in hypoglycemia, and they suggest that the effect of blockers of VSCCs in stroke, if any, is due to both blockade of VSCCs and increase in blood flow.

Animals↗
PubMed1991

Production, characterization and protective effect of monoclonal antibodies to Haemophilus paragallinarum serotype A.

Monoclonal antibodies (mAbs) to Haemophilus paragallinarum serotype A were obtained by fusion of murine myeloma cells (P3-X63-Ag8-U1) and spleen cells from BALB/c mice immunized with whole cells of strain 221. Enzyme linked immunosorbent assay with whole cells was used to show that the monoclonal antibodies are specific for serotype A of H. paragallinarum. Four monoclonal antibodies indicated hemagglutination-inhibition (HAI) activity against serotype A; their titers were 10(4)-10(5). By western blotting, two of these monoclonal antibodies reacted with a protein of molecular weight 39,000. Chickens treated with mAbs possessing HAI activity survived without clinical signs of infection. No challenge strain was isolated from these chickens, indicating that four mAbs with HAI activity suppressed growth of the challenge strain in the nasal cavity, whereas mAbs without HAI activity showed no passive protective effect. These results demonstrated that HI antibodies contributed to protection, and strongly suggest that hemagglutinin (HA) antigen, especially the epitopes which were recognized by these mAbs are important for protective immunity in chickens.

Animals↗