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Biomedical subjects

T Ohno

Publications and source records attributed to T Ohno.

At least 793 records · Page 44Linked to original sources

Molecular basis of ornithine transcarbamylase deficiency lacking enzyme protein.

We report an ornithine transcarbamylase(OTC)-deficient male patient who had no detectable immunoreactive materials but did have active mRNA for OTC-related protein. The total absence of OTC activity in the liver of the patient was caused by a complete lack of immunoreactive material, as determined by Ouchterlony double immunodiffusion, single radial immunodiffusion, and sodium dodecylsulphate-polyacrylamide gel electrophoresis of immunoprecipitate and of liver homogenate. However, mRNA coding for the precursor of OTC was clearly detected in autopsy specimens of the patient's liver as well as of controls in a cell-free translation system consisting of rabbit reticulocyte lysates and [35S]methionine. The labelled precursor of OTC synthesized in vitro with mRNA from the patient could be transported into rat liver and kidney mitochondria and processed to form a protein with a molecular weight indistinguishable from mature OTC, suggesting that there was no defect in the protein structure necessary for its transport into mitochondria. These results suggest that the primary defect of the OTC deficiency was located in the structural gene and that the labile OTC-related protein, after being synthesized with its mRNA, was degraded too rapidly to be detected by the method used.

Amino Acid Metabolism, Inborn Errors↗

Properties of retrovirus-like particles produced by a human breast carcinoma cell line: immunological relationship with mouse mammary tumor virus proteins.

Clonal derivatives 8 and 11 of the T47D human breast carcinoma cell line release particles that have the biochemical characteristics of a retrovirus. Particles recovered from cultures of [3H]uridine-labeled clone 11 had a density of 1.18 g/ml and contained 60-70S and 35S RNAs associated with reverse transcriptase activity. The production of these particles was steroid-dependent. Clone 8 particles had a higher density, 1.195 g/ml, and their production was independent of steroid hormone. By RIA, antigens crossreactive with the 52,000-dalton envelope glycoprotein gp52, the major external protein of mouse mammary tumor virus, were found associated with these particles and in the media. Most of the gp52-related antigen was in soluble form, but it was enriched in the particle preparation. A lesser amount of antigen was distributed within the cultured cells. Absorption of rabbit antibody to gp52 with clone 11 particle preparations eliminated the ability of this antibody to detect immunocytochemically a crossreactive antigen previously localized in tissue sections of human breast carcinoma. These results indicate that the particle isolates from T47D contain the same gp52-related antigen found in human breast carcinomas and constitute an excellent source for the purification and characterization of this antigen.

Breast Neoplasms↗

Differential recovery from potentially lethal damage in normal human lung fibroblasts after irradiation with 60Co gamma-rays and accelerated N-ion beam.

PLD recovery after irradiation with accelerated N-ion was examined and compared with that after irradiation with 60Co gamma-rays in normal human lung fibroblasts (IMR-90). No shoulder region was observed in the survival curve of the cells after N-ion irradiation. Ratios of D0 values before and after a 6-hour incubation in plateau phase were 1.1 and 1.8 for N-ion irradiation and gamma-ray irradiation, respectively. The results show that recovery after irradiation with high-LET radiation is slow and much less than after low-LET irradiation.

Cell Survival↗

Double-stranded cDNAs of hop stunt viroid are infectious.

Restriction fragments composed of only hop stunt viroid (HSV) cDNA were prepared from recombinant clone pHS-P4P, which carries four tandemly repeated HSV cDNAs, and inoculated into cucumber cotyledons. The results showed that double-stranded cDNAs consisting of 1 to 3 units of HSV sequences were infectious. In cucumber plants inoculated with these double-stranded cDNAs, infectious RNA molecules indistinguishable from authentic HSV were propagated.

Base Sequence↗

Fatty acid elongation activity in fibroblasts from patients with adrenoleukodystrophy (ALD).

The activities of microsomal fatty acid elongation and cytoplasmic de novo fatty acid synthesis were measured in human cultured skin fibroblasts. Both activities in fibroblasts from normal controls and patients with adrenoleukodystrophy (ALD) were compared and slight but a significant increase of elongation activities in ALD fibroblasts was demonstrated. On the other hand, there were no significant differences in the fatty acid synthetase activities. In this study, we measured microsomal fatty acid elongation activities in the presence of N-ethylmaleimide, which completely inhibited the activity of contaminating fatty acid synthetase and also the degradation of fatty acids, and made accurate determination of the elongation activities possible.

Adrenoleukodystrophy↗

Nucleotide sequence of the tobacco mosaic virus (tomato strain) genome and comparison with the common strain genome.

The sequence of about 4,500 nucleotides of the internal part of tobacco mosaic virus (TMV)-tomato strain (L) RNA has been newly determined using cloned cDNAs. Together with the previously determined partial sequences at both ends, the entire sequence of the 6,384 nucleotide genome has been completed. The 130K (1,115 amino acids), 180K (1,615 amino acids), 30K (263 amino acids) and coat protein (158 amino acids) cistrons are located at residues 72-3442, 72-4922, 4906-5700, and 5703-6182 on the genome, respectively. Sequence polymorphism was not observed except for heterogeneity in the length of the A cluster near the 3' end. The homology of the nucleotide sequences of TMV-L and TMV-vulgare, a common strain, is about 80% on average. Remarkable differences between them were found in a part of the N-terminal portion of the 130K/180K protein and the C-terminal portion of the 30K protein. A new method for cDNA cloning was developed by which the cDNA of the 5'-terminus of viral RNA can be cloned efficiently.

Base Sequence↗

Faecal bile acid profiles in patients with large bowel cancer in Japan.

To study the possible role of bile acids in carcinogenesis of the large bowel faecal bile acid profiles were analysed in detail in 14 patients with large bowel cancer and compared with 14 matched healthy subjects. The total faecal bile acid excretion was lower in the patients (297.3 +/- 402.8 mumol/day) than in the healthy subjects (470.6 +/- 231.1 mumol/day) (p less than 0.01), although the difference became insignificant when these data were expressed as mumol per wet or dry faecal weight. The faecal profiles of individual bile acids and their conjugates were similar in both groups except that 5 beta-chol-3-en-24-oic acid, a bacterial metabolite of sulpholithocholic acid, was found in nine cancer patients (64%) compared with only two healthy subjects (14%) (p less than 0.01). The significance of 5 beta-chol-3-en-24-oic acid in carcinogenesis needs further prospective and experimental studies.

Aged↗

Interaction of prostaglandin E2 and bradykinin in the induction of afferent splanchnic nerve discharges in cats.

In anesthetized cats, the administration of either bradykinin (BK) (0.3-3 micrograms/kg) or prostaglandin E2 (PGE2) (1-30 micrograms/kg) into the cranial mesenteric artery dose-dependently evoked the firing discharge in the proximal end of the afferent greater splanchnic nerves with a latency of about 10 sec, the pronounced contraction of the longitudinal muscle of the jejunum, and changes in blood pressure. PGE2 at the doses of 1-10 micrograms-kg i.a. potentiated the BK (1 microgram/kg i.a.)-induced firing discharge of the afferent splanchnic nerves of which latency was also shortened, but did not alter the BK-induced jejunal contraction and blood pressure change. However, trimoprostil (30 micrograms/kg i.a.), a trimethyl PGE2 derivative, did not change all of these responses to BK. Aspirin at 50 mg/kg i.v. markedly prevented the BK-induced nerve discharges, but not the BK-induced jejunal contraction. These results taken together indicate that PGE2 may be involved in the facilitatory response of afferent splanchnic nerve discharges to BK, but not involved in the BK-induced jejunal contraction and blood pressure change. The findings on trimoprostil present the possibility that derivatization of PGE2 could modify its inherent ability to produce adverse side-effects.

Animals↗

[Effects of bromazepam on responses of mucosal blood flow of the gastrointestinal tract and the gastric motility to stimulation of the amygdala and hypothalamus in conscious cats].

Electrical stimulation (ES) of the nucleus amygdaloideus centralis ( NAmC ) and basolateralis ( NAmBL ), like norepinephrine, decreased mucosal blood flow of the gastric antrum and duodenum and decreased antral motility amplitude in gallamine-immobilized cats. ES of the nucleus lateralis hypothalami (NHL) less extensively produced a similar action. The NAmC stimulation elevated BP and renal sympathetic discharges, whereas the NAmBL stimulation lowered BP. These findings indicate that the gastric and pressor responses to the NAmC stimulation may be attributed to an increase in cerebral sympathetic outflow. Bromazepam dose-dependently (0.1 approximately 1.0 mg/kg, i.v.) prevented these gastric, pressor and renal sympathetic responses to the NAmC stimulation, but it did not alter the depressor response to the NAmBL stimulation or the norepinephrine-induced reactions. Bromazepam less extensively attenuated the gastric and pressor responses to the NHL stimulation. Moreover, bromazepam inhibited stress-induced gastric ulcer formation in rats more markedly than cimetidine, sulpiride and metoclopramide. Bromazepam markedly decreased stress-induced selective increase in the glucose utilization rate in the NAmC among various amygdala nuclei. These results indicate that effects of bromazepam on the gastric and pressor responses to the NAmC stimulation may be due to the inhibition of central sympathetic outflow, and the NAmC are more sensitive to bromazepam than the NHL and other amygdala nuclei.

Amygdala↗

[Correlation between concentration of cytosol estradiol receptors and activities of RNA and protein synthesis in uterine myoma].

In an attempt to clarify the relationship between estradiol and uterine myoma, the concentration of the cytosol estradiol receptors (E2R) and the activities of RNA and protein syntheses (RS and PS) in uterine myoma and corresponding myometrium were measured. A 105,000 X g supernatant of tissue homogenate from which endogenous unbound steroid was removed by dextran-coated charcoal was used for the cytosol. Binding was measured by using the charcoal adsorption technique. RS and PS had been determined by the incorporation of 3H-Uridine and 14C-Leucine to the fresh tissue at 37 degrees C for 3 hours. The differences between paired samples of myoma and myometrium from the same uterus were statistically analyzed and the following results were obtained: The concentration of E2R in myoma was significantly higher than that in myometrium. But there was no significant difference in RS and PS between myoma and myometrium. There was a close correlation of the concentration of E2R, RS and PS between myoma and myometrium from the same uterus. The concentration of E2R did not correlate to RS and PS in myoma, whereas RS correlated with PS in myoma.

Adult↗

Inhibition of aminoacyl-transfer RNA formation by low-molecular substances from melanoma extract.

Two partially purified fractions of the ethanol precipitate (70-95%) of the water extract of Harding-Passey mouse melanoma, which inhibit protein and DNA syntheses of B-16 melanoma cells in culture, also inhibit protein synthesis in various cell-free systems. By examining their inhibitory effects on limited reactions of protein synthesis, it was found that one of them (ME II) inhibits protein synthesis by blocking aminoacyl-tRNA formation, while the other (ME IV) does not. This inhibition of aminoacyl-tRNA formation was not limited to specific amino acids. Since the amino acid-dependent pyrophosphate (PPi)-ATP exchange reaction catalyzed by aminoacyl-tRNA synthetases was not inhibited, it was concluded that some factor(s) in ME II inhibits amino acid transfer from aminoacyl-AMP to tRNA. ME II contains more than 20 proteins from 10,000 to 90,000 daltons. EDTA treatment of this fraction caused the release of low-molecular substances with inhibitory activity from the proteins. The molecular weights of the active substances are less than 5,000 daltons. The active low-molecular substances are apparently not peptides or nucleotides.

Adenosine Triphosphate↗

Growth factors.

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Animals↗

[Effect of electroacupuncture on the sympathetic nervous, endocrine and metabolic functions].

Electroacupuncture (1.5 volts, 0.13 msec duration, 5 Hz for 10 min) was applied to the ten sites of lumbodorsal region in women aged 20 to 47. Immediately after the acupuncture plasma noradrenalin concentration significantly increased 9 out of 20 subjects, while it decreased in 11. Plasma noradrenaline returned to the intitial level in both groups 30 min after the acupuncture. In the noradrenaline elevated group plasma insulin concentration and plasma insulin/glucagon molar ratio significantly decreased until 30 min after the acupuncture. Such changes were not observed in the noradrenaline decreased group. Plasma glucagon, dopamine-beta-hydroxylase, free fatty acids, glycerol, creatine kinase and blood glucose were not changed in both groups.

Acupuncture Therapy↗

Growth stimulation by direct cell-cell contact (contact stimulation) in normal human lung fibroblasts.

Clonal growth of the normal human lung fibroblasts, IMR-90, is stimulated efficiently by utilizing feeder fibroblasts. Under the sparse culture conditions, IMR-90 cells located close to the feeder cells formed colonies with a higher efficiency than those isolated from the feeders within the same dish. The IMR-90 cells in direct contact with the 3T3 cell feeders, as monitored by metabolic cooperation, showed a faster entrance into S phase than did the IMR-90 cells isolated from the feeders. The isolated cells, even when they remained closer to the feeder cells, entered S phase later than those of the IMR-90 cells making direct contact with the feeders with long pseudopods. Medium- and dish-surface-conditioning with the feeders resulted in marginal improvement of the clonal growth. These observations suggest that contact stimulation of growth occurs in sparse cultures of normal human lung fibroblasts.

Cell Communication↗