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Biomedical subjects

T Ohta

Publications and source records attributed to T Ohta.

At least 1,207 records · Page 67Linked to original sources
PubMed1986

[Simultaneous cytofluorometric studies on DNA and protein in endometrial adenocarcinoma--with reference to gestagen treatment].

In this study, the nuclear DNA and cellular protein in endometrial cancer cells were simultaneously determined by combined DNA-protein cytofluorometry (Olympus MMSP-RF) using a double staining method. Thirty-one cases of endometrial adenocarcinoma treated preoperatively with medroxyprogesterone-acetate were investigated for cytomorphological responses with special reference to DNA and protein content. The result of this study showed increases in DNA and protein over the normal range in all the cases of endometrial carcinoma. Gestagen produced a marked histological effect in 9 cases of well differentiated carcinoma and 2 cases of moderately differentiated carcinoma out of the 31 cases. On the other hand, no effect was found in cases of poorly differentiated carcinoma. Gestagen treatment induced changes in DNA and protein content according to morphological changes in cases of marked histological response. The population of over 4C or 4P cells on the DNA-protein histogram before gestagen treatment was 45.1% in cases of marked morphological response and 69.2% in cases of no response. This finding suggests a correlation between the effectiveness of gestagen treatment and the DNA-protein histogram. Estimation of such a cell population before gestagen administration is considered useful in gestagen therapy for endometrial adenocarcinoma.

Adenocarcinoma↗
PubMed1986

[A chronological study on gastric cancer originating from the fundus gland mucosa].

A chronological analysis of gastric cancer originating from fundic gland mucosa was made by measuring the tumor size with reference to the serosal invasion and peritoneal dissemination. As for serosal invasion by cancer cells there were significant differences in the group with tumors exceeding 4 cm in diameter, and peritoneal dissemination was liable to be seen in the group with those exceeding 5 cm. This suggests that gastric cancer originating from fundic gastric mucosa must be detected before it reaches 4 cm in diameter and that the intraperitoneal administration chemotherapeutic agents is recommendable, considering residual microcancer dissemination.

Adult↗
PubMed1985

Allosteric effect of fructose 1,6-bisphosphate on the conformation of NAD+ as bound to L-lactate dehydrogenase from Thermus caldophilus GK24.

The allosteric effect of fructose 1,6-bisphosphate (Fru-1,6-P2) on L-lactate dehydrogenase (L-lactate:NAD+ oxidoreductase, EC 1.1.1.27) from Thermus caldophilus GK24 was studied by means of 1H NMR analyses. The conformation of NAD+ as bound to the T. caldophilus enzyme was elucidated by analyses of the transferred nuclear Overhauser effects (TRNOE), in the presence and the absence of the allosteric effector, Fru-1,6-P2. Upon binding of Fru-1,6-P2 to the enzyme, the ribose ring of the adenosine moiety of NAD+ is converted from the C2'-endo form to the C3'-endo form. This C3'-endo form of the adenosine moiety is similar to that of NAD+ as bound to nonallosteric vertebrate enzymes. However, the anti conformation of the adenine-ribose bond of NAD+ as bound to the T. caldophilus enzyme is not affected by the binding of Fru-1,6-P2. In contrast, the syn conformation of the nicotinamide-ribose bond is converted to the anti form on the binding of Fru-1,6-P2, while the ribose ring remains in the C3'-endo form as found in the case of a nonallosteric enzyme. Such a conformational change of enzyme-bound NAD+ as found on TRNOE analysis is essentially involved in the allosteric regulation of the T. caldophilus enzyme by Fru-1,6-P2.

Adenosine↗
PubMed1985

The amino acid sequence of the fluorescein-labeled peptides of electric ray and brine shrimp (Na,K)-ATPase.

(Na,K)-ATPase from Torpedo californica (electric ray) and Artemia salina (brine shrimp) was labeled with fluorescein 5'-isothiocyanate (FITC) with concomitant loss of activity. Both inactivation and binding were inhibited in the presence of ATP. The sequence of the peptide resulting from tryptic digest containing labeled lysine from both enzymes is Tyr-Leu-Leu-Val-Met-Lys*-Gly-Ala-Pro-Glu-Arg. Thus the primary structure of this region is shown to be conserved in the enzymes of a nonvertebrate and a vertebrate.

Amino Acid Sequence↗
PubMed1985

Degradation mediated OH radical generation from synthetic cyclic peroxides: ESR studies.

Hydroxy radical generation on thermal decomposition of synthetic cyclic peroxides was determined by ESR using DMPO as a spin-trapping reagent. Both the 6- and 7-membered cyclic peroxides, 4-alkoxy-2,3-benzo-dioxan-1-ols and 4-alkoxy-2,3-benzodioxepin-1-ols, respectively, which were synthesized according to our idea of a radical-releasing drug, gave rise to DMPO-OH signals on heat treatment, i.e. under their degradation conditions. The signals were completely abolished with higher concentrations of OH scavenger.

Electron Spin Resonance Spectroscopy↗
PubMed1985

Apolipoprotein and lipid abnormalities in uremic children on hemodialysis.

Plasma lipids and six plasma apolipoproteins were studied in uremic children on hemodialysis. Significant increases in plasma triglyceride, apolipoproteins (Apo) C-II and C-III and decreases in total cholesterol, HDL-cholesterol, Apo A-I, Apo A-II and Apo B were found in uremic children. The levels of Apo C-I did not differ between uremic children and normal controls. The ratio of (Apo A-I + Apo A-II)/HDL-cholesterol was significantly increased. These results indicate that uremic children on hemodialysis have similar lipid and apolipoprotein abnormalities to those found in adults who may have a risk of cardiovascular disease.

Adolescent↗
PubMed1985

Colicin E3 and its immunity genes.

A DNA segment of plasmid ColE3-CA38 was cloned into pBR328 and its nucleotide sequence was determined. This segment contains the putative promoter-operator region, the structural genes of protein A (gene A) and protein B (gene B) of colicin E3, and a part of gene H. Just behind the promoter region, there is an inverted repeat structure of two 'SOS boxes', the specific binding site of the lexA protein. This suggests that the expression of colicin E3 is regulated directly by the lexA protein. Genes A and B face the same direction, with an intergenic space of nine nucleotides between them. ColE3-CA38 and ColE1-K30 are homologous in their promoter-operator regions, but hardly any homology was found in their structural genes. On the other hand, ColE3-CA38 is fairly homologous to CloDF13 throughout the regions sequenced, with some exceptions including putative receptor-binding regions. By deletion mapping of the immunity gene and recloning of gene B, it was shown genetically that protein B itself is the actual immunity substance of colicin E3. It was also found that the expression of E3 immunity partially depends on the recA function. Thus, we propose two modes of expression of E3 immunity: in the uninduced state, only a slight amount of protein B is produced constitutively to protect the cell from being attacked by the exogenous colicin; and in the SOS-induced state, a large amount of protein B is produced to protect the protein synthesis system of the host cell from ribosome inactivation by endogenously produced colicin E3.

Amino Acid Sequence↗
PubMed1985

Structure and expression of the ColE2-P9 immunity gene.

The primary structure and expression of the ColE2-P9 immunity gene (imm) were investigated. The imm gene is located behind the colicin gene (col) in the same orientation with an intergenic space of two base pairs. Although the imm gene was transcribed primarily in response to the SOS function of the host cell as well as the col gene, the immunity phenotype also appeared to be expressed by only a slight level of leaky transcription without an evident promoter. On comparing the ColE2-P9 sequence with those of relevant plasmids, a highly homologous sequence with the immE2 gene was found downstream of the immE3 gene of ColE3-CA38, and thus, an evolutional relationships could be deduced among some E-group Col plasmids.

Amino Acid Sequence↗
PubMed1985

Noninvasive technique using thallium-201 for predicting ischaemic ulcer healing of the foot.

A post-stress imaging study utilizing single intravenous doses of thallium-201 was performed on feet with trophic skin lesions. Forty-two ischaemic ulcers were classified into four basic types according to the presence and degree of the inherent inflammatory response of the ulcer in both the initial and delayed distributions. Both the relationship between ulcer type and prognosis and the effects of therapy within ulcer type were assessed. The results suggest that ulcers of Type I or Type II heal in response to conservative treatment, while ulcers of Type III, although undergoing healing, require surgical treatment to prevent a protracted hospitalization. In Type IV ulcers, healing is not to be expected at all with conservative therapy; therefore an early decision of amputation may be necessary if surgical measures are not indicated. The technique reported may be helpful not only in the prediction of spontaneous ulcer healing but also in the selection of appropriate treatment.

Adult↗
PubMed1985

Electron microscopic observations on sperm entry and pronuclear formation in naked eggs of the rose bitterling in polyspermic fertilization.

Unfertilized eggs of the rose bitterling (Rhodeus ocellatus ocellatus) were squeezed out of females that had an elongated ovipositor and were dechorionated mechanically with fine forceps in physiological saline. The dechorionated eggs were transferred into fresh water then inseminated at once by spermatozoa of the same species. A large number of spermatozoa was found on the surface of eggs that had not yet had cortical reaction following insemination. The surface of the naked eggs responded by formation of many small cytoplasmic protrusions (viz., fertilization cones) at sperm attachment sites. The formed fertilization cones were rosettelike structures formed by the aggregation of some bleblike swellings devoid of microvilli and microplicae. About 10 min after insemination, the fertilization cones retracted, but marks of their presence characterized by less microvilli and microplicae remained in the eggs 15 min after insemination. Many spermatozoa penetrated into the cytoplasm of each naked egg. The sperm nuclear envelope disappeared by means of vesiculation resulting from fusion of the inner and outer membranes. The sperm nucleus decondensed and developed into a larger male pronucleus. Smooth-surfaced vesicles surrounded the decondensing sperm nucleus and formed the new male pronuclear envelope. Sperm mitochondria and flagella were found in the egg 15 min after insemination. The response of the egg surface to sperm entry and pronucleus formation are discussed.

Animals↗
PubMed1985

Qualitative and quantitative analysis of erythrocyte surface membrane sialyl residues using affinity cytochemistry with special reference to diabetic patients.

Erythrocyte surface membrane sialyl residues were investigated by means of affinity cytochemistry using the avidin-biotin complex technique. Mild oxidation with the periodate (MO)-biotin hydrazide (BHZ)-ferritin avidin conjugate (FAv) sequence revealed numerous ferritin particles on erythrocytes from healthy donors. The ferritin particles attached on the perpendicularly sectioned membrane were seen at an average distance of 10 to 12 nm from the outer dense leaflet of the cell membrane. Pretreatment with neuraminidase followed by the MO-BHZ-FAv sequence almost eliminated erythrocyte ferritin labeling. Erythrocytes from diabetic patients showed less dense ferritin labeling compared with those from healthy donors. Quantiative analysis of sialyl residues demonstrated a marked reduction in ferritin labeling of erythrocytes from diabetic patients which was significantly less (p less than 0.01) than that of erythrocytes from healthy donors. This observation supports previous biochemical data demonstrating lower levels of surface membrane negative charge and sialyl residues on erythrocytes from patients with diabetes mellitus.

Adult↗
PubMed1985

Reflex control of the gastric motility by the vagus and splanchnic nerves in the guinea pig in vivo.

Gastric responses to electrical stimulation of the vagus and splanchnic nerves and to esophageal distension were observed in studies of the reflex control of the gastric motility in anesthetized guinea pigs in vivo. The gastric motility was inhibited by both vago-vagal and splanchno-vagal reflexes through the activation of non-adrenergic inhibitory nerve fibers and by splanchno-splanchnic reflex through the inactivation of the intramural cholinergic excitatory neurons. Distension of the lower esophagus caused a relaxation of the stomach which was mediated by an intrinsic reflex via intramural non-adrenergic inhibitory neurons. Furthermore, stimulation of the splanchnic nerve innervating the stomach seems to activate adrenergic inhibitory, cholinergic excitatory and probably some non-adrenergic inhibitory fibers.

Adrenergic alpha-Antagonists↗
PubMed1985

Effects of a novel fatty acid derivative [(7E)-8-(2-naphthyl)-5,6-trans-5,6-methano-7-octenoic acid] on arachidonic acid metabolism in cultured cells.

The effects of a novel synthetic fatty acid derivative (TEI-8005:(7E)-8-(2-naphthyl)-5,6-trans-5, 6-methano-7-octenoic acid) on arachidonic acid metabolism in some cultured cells were studied. The compound significantly stimulated prostaglandin (especially prostacyclin) biosynthesis in cultured vascular cells and gastric mucosal epithelial cells, and inhibited lipoxygenase product formation in n-butyrate-treated mastocytoma. In aortic smooth muscle cells in which cyclooxygenase activity was reduced, it strongly stimulated prostaglandin formation in young cells with reduced cyclooxygenase activity but had less effect in aged cells. These result indicated that TEI-8005 enhanced prostaglandin formation in cells with either normal or reduced cyclooxygenase activity.

Aging↗
PubMed1985

Variances and covariances of identity coefficients of a multigene family.

By using a model of gene conversion for treating concerted evolution of multigene families, a theory for calculating the variances and covariances of identity coefficients has been developed. Six coefficients on triple identity and 15 coefficients on quadruple identity are needed. The variances and covariances are obtained from the quadruple identity coefficients and divided into within-population and between-population components. The former represents the variation of identity coefficients among individuals within a population, whereas the latter represents the magnitude of fluctuation of population averages. Monte Carlo simulations confirmed the theoretical predictions at equilibrium.

Gene Conversion↗
PubMed1985

Immunocytochemical localization of Na+, K+-ATPase in the canine choroid plexus.

To determine the localization of Na+, K+-ATPase in the choroid plexus of the canine fourth ventricle, antisera against canine renal Na+, K+-ATPase holoenzyme and the alpha and beta subunits of the enzyme were employed and the distribution of reaction product examined at the light and electron microscopic level by means of the peroxidase-antiperoxidase immunohistochemical method. In the choroidal epithelial cells, antigenic sites were restricted to the outer surface of the apical plasmalemma, including the membranes of the microvilli. No reaction product was detected in the cytoplasm or along the lateral and basal plasmalemma. These findings strengthen the hypothesis that the apical border of the choroidal epithelial cell plays an important role in cerebrospinal fluid secretion as a result of active transport mediated by Na+, K+-ATPase.

Animals↗
PubMed1985

A model of duplicative transposition and gene conversion for repetitive DNA families.

A model of duplicative transposition and gene conversion for the evolution of repetitive DNA families was studied. In this model, transposition and conversion (both unbiased) are assumed to occur both within and between the genomes in a diploid cell, and any degree of linkage intensity is incorporated. The transition equations for allelic and nonallelic identity coefficients have been formulated by using the previous results. The results are widely applicable to many repetitive sequences, from dispersed families like transposons to tightly linked multigene families. It has been shown through extensive numerical studies on equilibrium properties that duplicative transposition and gene conversion have very similar effects on nonallelic identity coefficients, but that allelism and allelic identity are greatly influenced by the relative rates of occurrence of the two processes.

Chromosomes↗