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Biomedical subjects

T Shimada

Publications and source records attributed to T Shimada.

At least 955 records · Page 53Linked to original sources
PubMed1982

Developmental changes in non-histone chromosomal proteins of bullfrog (Rana catesbeiana).

1. Chromatins were isolated from liver, brain, kidney, spleen, heart muscle and erythrocytes of the bullfrog and its tadpole, Rana catesbeiana and their non-histone chromosomal proteins (NHC proteins) were compared by a simple electrophoretic method. 2. No qualitative but quantitative variations in the composition of NHC proteins were found among the tissues examine. 3. The tissue of tadpole and frog were classified into three groups according to their electrophoretic pattern of NHC proteins' brain, heart muscle and spleen showing almost the same pattern, liver and kidney showing different pattern in some components, and erythrocytes showing markedly different pattern. 4. Component D3 occurring i the frog liver, not in the tadpole, was found to increase in the tadpole liver during natural and thyroxine-induced metamorphosis.

Aging↗
PubMed1982

Intronless human dihydrofolate reductase genes are derived from processed RNA molecules.

Three groups of recombinant bacteriophage containing coding sequences for dihydrofolate reductase (DHFR; tetrahydrofolate dehydrogenase; 5,6,7,8-tetrahydrofolate:NADP+ oxidoreductase, EC 1.5.1.3) were isolated from two human DNA clone libraries. One recombinant (lambda hDHFR-1) contains three exons that encode the COOH-terminal portion of human DHFR. The other two human DHFR genes (hDHFR-psi 1 and hDHRF-psi 2) lack introns. hDHFR-psi 2 contains several in-phase termination codons and is only 93% homologous to the normal human DHFR coding sequences, whereas hDHFR-psi 1 has an open reading frame and is virtually identical to the coding sequence of the normal DHFR gene. The region of DNA sequence homology between each intronless gene and the normal DHFR gene extends 2.9 kilobases beyond the end of the coding sequences. At the 3' end of this homologous sequence, each intronless gene has an A-rich tract. The lack of introns and the presence of the 3' A-rich tract suggest that hDHFR-psi 1 and hDHFR-psi 2 were derived from processed RNA molecules. A short DNA sequence, 60 nucleotides 5' to the ATG start codon in lambda hDHFR-psi 2, is directly repeated immediately after the 3' A-rich tract; such terminal direct repeats also flank integrated proretroviruses and transposable DNA elements and are thought to be the hallmark of inserted DNA sequences.

Base Sequence↗
PubMed1982

Serological comparison of two collections of Vibrio cholerae non O1.

Two large, independently obtained collections of vibrio cholerae non O1, containing 59 and 67 reference strains, respectively, were compared serologically in four laboratories. Twenty strains in each collection were considered identical, and an additional 16 strains in each collection were probably identical. Twenty-eight unique strains were identified, and inconclusive results were obtained with 25 strains. Nine strains were not considered V. cholerae in at least one testing laboratory. Of these, five showed insufficient correspondence to V. cholerae O1 by DNA hybridization to be considered V. cholerae.

Agglutination Tests↗
PubMed1982

A case of membranous nephropathy associated with thyroid antigens.

A 54-year-old woman who had proteinuria due to stage II membranous nephropathy is reported. She was treated with indomethacin for proteinuria and developed drug-induced hepatitis four months later. Liver dysfunction gradually recovered, but hormonal studies revealed abrupt fall of T3 and T4 and concomitant elevation of TSH levels within a month. Pathological findings of thyroid specimen and positive antithyroglobulin and antimicrosomal antibodies were compatible to chronic thyroiditis. In the second renal biopsy, glomerular deposits of thyroglobulin, thyroid microsomal antigens and IgG were demonstrated by immunofluorescence. Therefore, membranous nephropathy in this patient is presumed to be caused by immune complexes mediated by thyroid constituents. We believe that this is a precious case because continuous changes in T3, T4 and TSH were followed in a course of chronic thyroiditis, especially in the stage of progress to hypothyroidism, and the chronic thyroiditis was shown to be involved in the membranous nephropathy.

Antigens↗
PubMed1981

Occurrence of H1o-like protein and protein A24 in the chromatin of bullfrog erythrocytes lacking histone 5.

Electrophoretic analysis of acid-soluble chromosomal protein isolated from the erythrocytes of the bullfrog Rana catesbeiana reveals that the nucleated erythrocytes contain five major histones (H1A, H2A, H2B, H3, and H4) and three minor histone-like proteins (H1B, R1, and R2). Histone 5, found as an additional major histone of avian erythrocytes, is not detected in the frog erythrocytes. Three minor components of the bullfrog erythrocytes, which are not present in the avian erythrocytes, have been purified to electrophoretic homogeneity and characterized by amino acid analysis, NH2-terminal analysis, tryptic peptide mapping, and immunological techniques. H1B extracted with 5% HClO4 along with H1A has a very similar amino acid composition and tryptic peptide map to H1o, a subfraction of lysine-rich histones found in nondividing mammalian cells. Microcomplement fixation also shows that H1B and bovine liver H1o share some common antigenic determinants. R1, a basic protein having a ratio of basic/acidic amino acids of 2.0 and 20 mol % lysine, is distinguished from any chromosomal proteins characterized so far on the basis of electrophoretic mobility and amino acid composition. On the other hand, R2 is identified as protein A24 on the basis of its electrophoretic mobility, amino acid composition, and tryptic peptide map. Since H1o and protein A24 are considered to be involved in the inhibition of DNA replication and RNA synthesis, respectively, H1o-like protein and protein A24 in the frog erythrocyte lacking H5 may have central roles in genetic inactivation during erythrocyte maturation.

Amino Acids↗