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Biomedical subjects

T Imamura

Publications and source records attributed to T Imamura.

At least 631 records · Page 35Linked to original sources
PubMed1983

Phenobarbital pretreatment protects against morphologic changes in rat bronchiolar epithelium caused by an impurity of malathion.

Oral administration (20 mg/kg) of O,O,S-trimethyl phosphorothioate (OOS) causes delayed toxicity in rats; ie, death occurs as late as 28 days after treatment. OOS-treated rats show morphologic changes in the bronchiolar epithelium of the lung; nonciliated (Clara) cells are fewer but larger 3 days after treatment. We have now found that pretreatment with the P-450-dependent mixed-function oxidase inducer, phenobarbital, protects against the morphologic changes caused by OOS. These results support the view that the lung is a target organ of the delayed toxicity caused by OOS and that OOS detoxification is mediated by P-450-dependent metabolism.

Animals↗
PubMed1982

Structure of cloned delta-globin genes from a normal subject and a patient with delta-thalassemia; sequence polymorphisms found in the delta-globin gene region of Japanese individuals.

The delta-globin genes of a normal Japanese and a Japanese patient with homozygous delta-thalassemia were cloned, and the nucleotide sequence of a region including the gene was determined. Comparison of the nucleotide sequences of these two individuals with that of pH delta 1, delta-globin clone from the gene library constructed by Maniatis et al., showed differences in the large intervening sequence (IVS 2), at positions 137, 151, 186, 188, 291, 292 and 540 as one base substitutions, at 339 and 823 as one base additions, at 548 as a one base deletion, and a 9 bp duplication between positions 651 and 659, and differences in the 3'-flanking sequence at 51 and 98 nucleotides 3' to the AATAAA sequence. However, in the region studied, no differences was observed in the nucleotide sequences of the normal subject and the patient with delta-thalassemia. Therefore, these differences may represent polymorphisms of the delta-globin gene present in Japanese individuals. These data suggest that IVS 2 is more divergent than other regions, and that a DNA region(s) other than the globin gene may affect expression of the gene.

Amino Acid Sequence↗
PubMed1982

A new electrophoretic variant of hemoglobin (Ogi) in which a leucine residue is replaced by an arginine residue at position 34 of the alpha-chain.

Hemoglobin Ogi, in which an arginine is substituted for a leucine residue at position 34 of the alpha-chain, was detected in a Japanese family. Although slightly increased oxygen affinity is associated with this amino acid substitution in the alpha 1 beta 1 contact, it is without obvious deleterious effect on the hematological parameters of the individuals heterozygous for this variant.

Amino Acid Sequence↗
PubMed1982

Auditory brainstem response (ABR) in infantile Gaucher's disease.

The auditory brainstem response (ABR) was studied in an infant with Gaucher's disease. The infant was normal until the age of three months. His illness began with stridor, strabismus, inguinal hernia and failure to thrive. Thereafter, muscular rigidity with opisthotonus, ocular palsies, difficulty in swallowing and respiratory failure due to central origin developed. He died of respiratory failure due to central origin developed. He died of respiratory failure at the age of one year and four months. The ABR was abnormal at six and eight months of age. Initially, at the age of six months, there was a lengthening of the peak latencies of wave I, II and III and disappearance of the waves after IV. But at eight months, more marked lengthening of the peak latencies of the waves and the disappearance of waves after III were noted as his general condition deteriorated. The autopsy revealed relative preservation of the nuclei and tracts of the auditory pathways in the brainstem. The ABR was useful for monitoring the progress of the disease in this patient because it made detection of brainstem lesions possible.

Adult↗
PubMed1982

Purification and characterization of an aminopeptidase from porcine liver.

An aminopeptidase was purified about 700-fold from porcine liver homogenate by ammonium sulfate fractionation and a series of column chromatographies on DEAE-cellulose, Sephadex G-150, DEAE-Sepharose, and hydroxyapatite. The purified enzyme had a specific activity of 4.6 mumol X min-1 X mg-1 using L-leucine beta-naphthylamide as the substrate. The molecular weight of the enzyme was about 96,000 as determined by Sephadex G-150 column chromatography. The enzyme had a broad specificity and a pH optimum between 6.5 and 7.0 for hydrolysis of alpha-aminoacyl-beta-naphthylamines, and it hydrolyzed the beta-naphthylamides of aliphatic, basic, and aromatic amino acids. The enzyme also hydrolyzed peptide substrates with phenylalanine residues as their amino-termini, but it did not hydrolyze L-phenylalanyl-L-proline. The enzyme was inhibited by metal-chelating agents, sulfhydryl reagents, heavy metals, bestatin, and puromycin. Activity of the enzyme inhibited by sulfhydryl-reactive reagents was restored by the addition of sulfhydryl compounds. The enzyme was activated by cobaltous ion and the values of both Km and Vmax increased. The activation was pH-dependent and above pH 7.5 cobalt ion behaved as an inhibitor of the enzyme. No metal ions other than cobaltous ion stimulated the enzyme appreciably.

Aminopeptidases↗
PubMed1982

Physico-chemical properties of acetylcholine receptor proteins from Narke japonica.

The molecular weights of acetylcholine receptor proteins from Narke japonica were determined using a combination of high-speed gel filtration and the low angle laser light scattering technique. The values obtained were 460,000 and 240,000 for the dimer and monomer, respectively. By use of a weakly charged silica gel column for high-speed gel filtration calibrated by considering electrostatic interactions between proteins and gel surfaces, the Stokes radii of the proteins were estimated as 7.3 nm and 6.2 nm. Chromatography in 6 M guanidine hydrochloride (GmHCl) showed that the proteins were hardly dissociated to subunits, and CD measurements confirmed that the proteins are resistant to GmHCl denaturation. These results suggest that strong hydrophobic interactions exist among the receptor subunits and probably within the subunits themselves.

Animals↗