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Biomedical subjects

T Uchida

Publications and source records attributed to T Uchida.

At least 1,369 records · Page 76Linked to original sources
PubMed1977

Transmission and scanning electron microscopic observations of mouse adrenocortical adenoma cells (Y-1) in non-stimulated and stimulated states.

ACTH sensitive murine adrenocortical adenoma cells (Y-1) were examined by transmission and scanning electron microscopes under non-stimulated and stimulated conditions. They showed the ultrastructural characteristics which were fairly different from those of the original adrenocortical cells of LAF1 mice. The smooth-surfaced endoplasmic reticulum (sER) were poorly developed, and the mitochondrial cristae showed lamellar rather than tubular or tubulo-vesicular type. Administration of ACTH induced rounding-up of the Y-1 cells with slight increase in sER, BUt no mitochondria with vesicular inner structure appeared. The effects of dbcAMP on the morphology of the Y-1 cells were similar to those of ACTH except that the rounding-up occurred more rapidly and uniformly.

Adenoma↗
PubMed1977

Isolation from corynebacterium diphtheriae C7(beta) of bacterial mutants that produce toxin in medium with excess iron.

Five mutants that produce toxin in medium with excess iron were isolated from strain C7(beta). The iron content of bacteria grown on this medium was considerably higher than that of C7(beta) cells grown in medium containing the minimum amount of iron needed to inhibit toxin production. When the nonlysogenic, nontoxinogenic strain C7(-) was lysogenized with phages from each of the mutants, toxin production by all of the resulting lysogens, like that by parent strain C7(beta), ceased upon iron addition. When the mutants were superinfected with beta45 phage, both toxin and CRM45 were produced in medium with excess iron. One of the mutant strains lost its prophage as a result of treatment with ultraviolet light. When the cured strain was lysogenized with phage carrying a mutation in the tox structural gene, the lysogen produced the mutant protein at the maximum rate in medium with excess iron. These findings show that the mutant strains are not phage mutants, but are bacterial host mutants, and that a host factor(s) is involved in the inhibition of toxin production by iron.

Bacteriophages↗
PubMed1977

Origin of the secondary response induced by flash stimulation under barbiturate anesthesia in the rabbit.

The photically evoked secondary response of the visual cortex was studied in a rabbit anesthetized with pentobarbital sodium. The following results were obtained: 1) The secondary response (P2) under anesthesia was a simple positive potential having a long latency and resembled the primary response (P1) in waveform. 2) The latency of P2 shortened gradually as the recovery from anesthesia proceeded. 3) P2 was usually smaller than P1 in amplitude when evoked with a strong flash, but larger than P1 when evoked with a weak flash. 4) Electrical stimulation of the superior colliculus (SC) induced in the visual cortex a positive potential which had a long latency comparable to that of P2. On the contrary, stimulation of the lateral geniculate body (LGB) evoked a short latency, positive potential similar to P1, but failed to evoke a positive potential comparable to P2. 5) A partial lesion of LGB led to a decrement of P1, while lesion of SC resulted in a decrement of P2. 6) Cooling of SC resulted in a rapid reduction and disappearance of P2 as well as the negative potential in SC. 7) There were a considerable number of visual cortical neurons which fired commonly during the phases of P1 and P2. These results suggest that P2 might be derived through the extrageniculo-cortical system which is relayed at SC. The mechanism by which P2 was manifested under anesthesia was discussed.

Anesthesia, Intravenous↗
PubMed1977

A comparative study on lysosomal accumulation of gallium-67 and indium-111 in Morris hepatoma 7316A.

Intracellular localization of Ga-67 and In-111 was investigated in Morris hepatoma 7316A and in normal Buffalo rat liver cells by a cell fractionation method at 48 hr after an intraperitoneal injection of the nuclides. Lysosomal fractions of the tumor and normal liver cells had the highest relative specific radioactivities of the nuclides (p less than 0.001). In a gradual solubilization experiment, the release of the nuclides at the same time as the acid phosphatase from the lysosomal fractions (p less than 0.001) was thought to indicate that lysosomes are the site of accumulation for both nuclides whether in tumor or normal liver cells. Fragility of the tumor lysosomes might be inferred from the significantly greater regression coefficient in relation to the lysosomal fraction of tumor cells than that of normal liver cells when labeled with Ga-67 (p less than 0.001). The poorer confidence limit for the regression coefficient in relation to the lysosomal fraction of tumor cells labeled with Ga-67 seemed to indicate that Ga-67 determines lysosomal functions of tumor cells more precisely than In-111.

Animals↗
PubMed1976

Synthesis of various phosphodiesters and phosphomonoesters with ribonuclease N.

1. 3'-Guanylyl-ethanol, 3'-guanylyl-propanol, and 3'-guanylyl-alpha-glycerol were synthesized by ribonuclease N1 [EC 3.1.4.8] using guanosine 2',3'-cyclic phosphate as a phosphate donor and various alcohols as phosphate acceptors. The yields of these phosphodiesters were 15%, 13.5%, 38.2%, respectively, with respect to phosphate donor under the optimum conditions. No phosphodiester was synthesized when 2-propanol was used as a phosphate acceptor. Thus, primary alcoholic hydroxyl groups may be regarded as the preferred phosphate acceptor. 2. 3'-Guanylyl-glucose and 3'-guanylyl-ribose were synthesized using glucose and ribose as phosphate acceptors. Under the optimum conditions, the yields of guanylyl-glucose amounted to 52.0%, while that of guanylyl-ribose was much lower. The guanylyl-glucose can be regarded as 3'-guanylyl-6-glucopyranose, based on the results of periodate oxidation. 3. Neither hydroxyamino acids (serine and threonine) nor N-acetylserinamide could be phosphorylated under the conditions used for the above phosphorylations. 4. 3'-Guanylyl-glycerol obtained as above was hydrolyzed by snake venon phosphodiesterase to produce glycerol 3-phosphate. The latter consisted of L-glycerol 3-phosphate (ca 17%) and the D-isomer (ca. 83%). Ribonuclease N1 thus catalyzes an asymmetric synthesis.

1-Propanol↗
PubMed1976

Evaluation of recommended methods for radioisotopes red cell survival studies.

Mean red cell life-span in normal subjects and in patients with various hematological disorders was examined with 51Cr and DF32P. The results with 51Cr were corrected for 51Cr elution using correction factors. The results by the two methods agreed fairly well with each other. Elution rate in various hematological disorders was 2.3% per day or less except for the patients with extracorpuscular hemolytic agents such as autoimmune hemolytic anemia or congestive splenomegaly. It is concluded that estimates of mean red cell life-span by corrected 51Cr method are more useful and sufficient than uncorrected 51Cr or DF32P method in general hematological disorders.

Chromium Radioisotopes↗