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Biomedical subjects

M Shibuya

Publications and source records attributed to M Shibuya.

At least 505 records · Page 28Linked to original sources
PubMed1981

Study on erythrocyte lipids and osmotic fragility in elderly people with anemia.

Hospitalized aged patients suffering from a sequelae of cerebral vascular disorders accompanied by anemia were studied to clarify the relationship among the osmotic fragility of red blood cells, plasma lipids and the phospholipids fraction of erythrocytes. As a result, with a decrease in hemoglobin (Hb) concentrations, each lipid fraction of plasma decreased remarkably and the phospholipid composition ratio of erythrocytes was disturbed. In accordance with the fluctuation of the lipid fraction of erythrocytes, increases in osmotic fragility of erythrocytes and in resistance to osmotic lysis were observed.

Age Factors↗
PubMed1980

Homology exists among the transforming sequences of avian and feline sarcoma viruses.

Fujinami sarcoma virus (FSV) of chickens does not contain nucleotide sequences related to the src gene of Rous sarcoma virus, but it carries unique sequences of at least 3000 bases, which are likely to code for the transforming protein of this virus. Using radioactive DNA complementary to FSV-unique sequences, we investigated the relatedness of FSV to other sarcoma-leukemia retroviruses in vertebrates. Under conditions of moderate stringency, no cross-hybridization was detected between FSV cDNA and RNAs of Rous sarcoma virus, Y73 avian sarcoma virus, several representative avian acute leukemia viruses, or Abelson murine leukemia virus. This cDNA, however, did hybridize with RNA of PRCII sarcoma virus of chickens to the extent of 56%. In addition, FSV cDNA was found to hybridize with RNAs of Gardner-Arnstein and Snyder-Theilen strains of feline sarcoma virus to the extent of 27% and 19%, respectively, but not with RNA of McDonough feline sarcoma virus. Studies on thermal denaturation of hybrids showed that the melting temperatures of the heteroduplexes of the FSV cDNA with RNAs of PRCII and Gardner-Arnstein feline sarcoma virus were 7 degrees C and 12 degrees C lower, respectively, compared with the melting temperature of the homologous hybrid of FSV, and suggested less than 10% mismatching in both heteroduplexes. These results indicate that nucleotide sequences closely related to at least a part of FSV-unique sequences are present in the genomes of other sarcoma viruses obtained in chickens and in cats.

Alpharetrovirus↗
PubMed1979

Cloning of an EcoRI fragment carrying E. coli tufA gene.

EcoRI fragments of the transducing phage lambda fus3 DNA have been linked to the ColEl derivative plasmid RSF2124 (ColEl-Apr) DNA using bacteriophage T4 ligase. Among the plasmids formed, one designated pTUAl was found to contain the E. coli tufA gene. The proof for the presence of tufA gene in pTUAl is based on the following observations: (1) ability of pTUAl DNA and is EcoRI fragments to direct synthesis of EF-Tu in a cell-free protein synthesizing system; and (2) RNA . DNA hybridization of RNA transcribed from phage lambda rifd18 carrying tufB with DNA from pTUAl.

Coliphages↗
PubMed1979

Dopamine-sensitive adenylate cyclase activity in the striatum in Parkinson's disease.

Dopamine (DA) sensitive adenylate cyclase activity was measured in homogenates of caudate nucleus and putamen from frozen brain of eight Parkinsonian patients and nine controls. In the control group, there was no difference in enzyme activity in respect to sex or age (21--77 years old). Caudate nucleus and putamen exhibited similar mean activity. In the Parkinsonian group, there was a significant decrease in both basal (by 50%) and DA stimulated (by 80%) activities compared with that of control group. This suggests that there may exist a functional disturbance in the postsynaptic (post-DA-nergic) region in the striatum of patients with Parkinson's disease; in addition, the decrease in basal as well as DA stimulated activity as measured in homogenates may not be the biochemical substrate for the hypothetical "denervation supersensitivity" expected to occur in Parkinson's disease.

Adenylyl Cyclases↗
PubMed1979

Studies on stringent control in a cell-free system. Regulation by guanosine-5'-diphosphate-3'-diphosphate of the synthesis of elongation factor Tu.

The biosynthesis of elongation factor Tu (EF-Tu) has been studied in a cell-free system with DNA of the transducing phage lambdarifd18 as a template. It was found that the synthesis of EF-Tu in this system was inhibited by about 60% in the presence of 0.3 to 0.6 mM guanosine-5'-diphosphate-3'-diphosphate (ppGpp). The syntheses of several ribosomal proteins encoded in this template, i.e. L1, L10, L11, and L7/L12, were also depressed, whereas those of phage lambda proteins were rather enhanced by the addition of ppGpp. By separating the reaction into two steps, i.e., transcription and translation, the effect of ppGpp was shown to occur at the level of transcription. Several analogs, such as guanosine-5'-diphosphate-3'-monophosphate (ppGp) and guanosine-5'-diphosphate (ppG), were without effect. The formation of mRNA for EF-Tu was assessed directly by specific hybridization with pTUA1 DNA carrying tufA gene. The results clearly indicated that the synthesis of tufB . MRNA was severely and selectively inhibited by ppGpp.

Bacteriophage lambda↗
PubMed1978

A new extragenic suppressor of cya mutation. Mutant cyclic AMP receptor protein with an increased affinity for cyclic AMP.

A strain bearing an extragenic suppressor of cya mutation was isolated as a second-site revertant of an adenylate cyclase deficient strain. The mutant was unable to synthesize cAMP but showed normal fermentation profiles and growth properties on a variety of carbon sources. The site of reversion was mapped in, or near, the structural gene for the cAMP receptor protein. Structural alteration of the protein was directly demonstrated by the following biochemical observations: (i) A 10-fold decrease in the dissociation constant for cAMP, (ii) an acidic shift in the isoelectric point, and (iii) the altered binding properties to lambdah80dlac ps DNA.

Carbohydrate Metabolism↗
PubMed1978

A newly designed multipurpose microneurosurgical head frame. Technical note.

A new multipurpose head frame has been designed for microneurosurgery. It consists of a head holder with a frame to hold self-retaining brain retractors, hand rests, instrument holders, a plate for cotton patties, and skin-flap retractors. It has been satisfactorily used in 100 operations for 1 year.

Humans↗