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H Kaji

Publications and source records attributed to H Kaji.

At least 181 records · Page 10Linked to original sources
PubMed1991

Ostrich crystallins. Structural characterization of delta-crystallin with enzymic activity.

Lens crystallins from the African ostrich (Struthio camelus) were isolated and characterized. Four crystallin fractions corresponding to alpha-, delta/beta- and beta-crystallins similar to those of duck crystallins were isolated, but epsilon-crystallin was found to be absent. The native molecular masses and subunit structures of the purified fractions were analysed by gel filtration. SDS/PAGE and isoelectric focusing, revealing various extents of heterogeneity in each orthologous crystallin class. An ion-exchange chromatographic method was used for the large-scale preparation of delta-crystallin suitable for structural and enzymic studies. It was unexpectedly found that the purified native delta-crystallin of ostrich lens possessed high argininosuccinate lyase activity, in contrast with chicken delta-crystallin. The c.d. spectra indicated a predominant beta-sheet structure in alpha- and beta-crystallins, and a significant contribution of alpha-helical structure in the delta-crystallin fraction. The estimate of secondary structures from c.d. spectroscopy for each crystallin class bears a resemblance to that of duck crystallins, except that ostrich delta-crystallin possesses much less helical content than duck delta-crystallin. Comparison of crystallin compositions and structures from aquatic and terrestrial birds revealed distinct differences.

Amino Acids↗
PubMed1991

Relationship between glucose tolerance and quantitative changes of islet cells in chronic obstructive pancreatitis due to pancreatoduodenal cancer.

This study was conducted to clarify the relationship between indicators of preoperative glucose tolerance and quantitative changes of endocrine cells in the islet of Langerhans in patients with chronic obstructive pancreatitis due to pancreatoduodenal cancer. Twenty-one specimens of pancreatic tissue obtained from patients who underwent pancreatoduodenectomy or total pancreatectomy for pancreatoduodenal cancer were divided into four groups according to the degree of fibrosis (Grades 0-III). Islet cells in serial sections were stained immunohistochemically to determine the proportions of B-, A-, D-, and PP-cells in the islets of Langerhans. In patients with pancreatic tissue with the most severe fibrosis, of several preoperative glucose metabolism indices measured, it was found that the ratio of integrated value of change in serum insulin to that of serum glucose (sigma delta IRI:sigma delta BS) was significantly decreased. There was a significant positive correlation between proportion of B-cells, and both the ratio of change in insulin to that of glucose (delta IRI:delta BS) and sigma delta IRI:sigma delta BS. On the other hand, there was a significant negative correlation between proportion of A-cells and sigma delta IRI:sigma delta BS. The present data strongly suggest that it is possible to estimate the degree of fibrosis and to quantify changes of the islet cells prior to surgery in patients with obstructive pancreatitis due to pancreatoduodenal cancer by calculating these glucose metabolism indices, and that sigma delta IRI:sigma delta BS is a particularly useful index.

Chronic Disease↗
PubMed1991

[A case of pulmonary leiomyoma].

We report a case of pulmonary parenchymal leiomyoma. The patient was a 35- year-old female with a tumor in anterobasal segment of the left lung. Enucleation was performed. The tumor was ball type and 2 cm in diameter, showing smooth and reddish brown cut surface. Microscopic and electron microscopic histology proved it to be leiomyoma.

Adult↗
PubMed1990

Comparison of the gamma-crystallins isolated from eye lenses of shark and carp. Unique secondary and tertiary structure of shark gamma-crystallin.

gamma-Crystallin isolated from the shark of cartilaginous fishes was compared with the cognate gamma-crystallin from the carp of bony fishes. Distinct differences in amino acid compositions, primary, secondary and tertiary structures were found. The most salient features of shark gamma-crystallin lie in the fact that this crystallin possessed a significant alpha-helical structure in the peptide backbone as revealed by circular dichroism study, in contrast to those orthologous gamma-crystallins from other vertebrate species including bony fishes which all show a predominant beta-sheet secondary structure. The tertiary structure as reflected in the intrinsic microenvironments of various aromatic amino acids in the native crystallins also shows unambiguous differences between these two classes of gamma-crystallins. N-Terminal sequence analysis corroborates the structural differences between shark and carp gamma-crystallins. gamma-Crystallin from the more primitive shark seems to be more in line with the main evolutionary phylogeny leading to the modern mammalian gamma-crystallin.

Amino Acid Sequence↗
PubMed1990

Effect of human epidermal growth factor (hEGF) on splanchnic circulation in dogs.

The effect of intravenous administration of human epidermal growth factor on the splanchnic blood flows was examined in anesthetized dogs, using an ultrasonic transit-time volume flow meter. Human epidermal growth factor (0.1, 0.5 and 1 microgram/kg) significantly increased blood flows in the portal vein (36.9 +/- 7.4% at 1 microgram/kg) and the superior mesenteric artery (49.0 +/- 16.8% at 1 microgram/kg). Systemic blood pressure monitored simultaneously was significantly decreased (8.4 +/- 1.2% at 1 microgram/kg). This study is the first to demonstrate that intravenous administration of epidermal growth factor increases the portal venous blood flow.

Animals↗
PubMed1990

The role of microfilaments and microtubules in apical growth and dimorphism of Candida albicans.

Cytoskeleton inhibitors were used to study morphogenesis in the pathogenic and dimorphic fungus Candida albicans. Nocodazole is a specific microtubule inhibitor and chloropropham (CIPC), at high concentrations, is an inhibitor of microtubules and microfilaments. Distribution of microtubules and microfilaments was studied by immunofluorescence techniques using anti-tubulin antibody with FITC-conjugated secondary antibody, and by staining with Rh-phalloidin. Nocodazole did not arrest apical cell elongation at a concentration (20 micrograms ml-1) that inhibited nuclear division and migration. Cytoplasmic and nuclear microtubules disappeared within 30 min in filamentous cells under these conditions. However, the Rh-phalloidin-stained actin granules which were localized in the tips of filamentous cells, and the microfilaments, were arranged normally at this concentration of nocodazole. Growth, and normal distribution of microtubules and microfilaments, were inhibited by a high concentration (200 micrograms ml-1) of CIPC. At a concentration (100 micrograms ml-1) of CIPC that permitted nuclear division, apical cell elongation was arrested, and filamentous growth was converted into yeast growth. At this concentration of CIPC, microtubules were distributed normally in filamentous cells. Long microfilaments were not observed, and actin granules did not localize in the tips of filamentous cells, but were distributed throughout the cytoplasmic cortex. Our results show that cytoplasmic microtubules are not essential for the elongation of filamentous cell tips but that microfilaments are apparently essential for this process.

Actin Cytoskeleton↗
PubMed1989

An in vivo analysis of c-myc and c-fos expression during terminal erythroid differentiation in mouse spleen progenitors.

Using thiamphenicol and scheduled bleeding, we were able to induce an adequate number of erythroid stem cells (CFU-e) in mice in order to conduct an in vivo study of the changing expression of c-myc and c-fos oncogenes during erythropoiesis. Results indicated that c-myc and c-fos are active in erythropoiesis and have a similar pattern of expression. A large decrease in expression of both c-myc and c-fos occurs when erythroid cells begin the biochemical transition into mature phenotypes, i.e., when RNA synthesis is down-regulated.

Animals↗
PubMed1989

Studies on chemical synthesis of human cystatin A gene and its expression in Escherichia coli.

A synthetic gene containing the coding sequence for the human cysteine proteinase inhibitor, cystatin A, was obtained by enzymatic assembly of 20 oligodeoxyribonucleotides which had been chemically synthesized by the solid phase phosphoramidite method. It was cloned into an Escherichia coli plasmid. The expression plasmid for cystatin A was constructed by introducing the synthetic gene downstream of the tac promoter of an E. coli plasmid which is a derivative of pKK223-3 with high copy number. The gene was expressed in E. coli JM109 without IPTG-induction. The expression of cystatin A was detected by SDS-polyacrylamide gel electrophoresis of the E. coli JM109 lysate, followed by immunoblotting using rabbit antiserum raised with human epidermal cystatin A and alkaline phosphatase-conjugated goat anti-rabbit IgG. The result showed that the molecular weight of the expression product is identical with that of the authentic protein and the antigenic properties are also the same. Furthermore, the expression product purified with a CM-papain Sepharose affinity column and FPLC system with a Mono-Q column showed the same inhibitory activity for various cysteine proteinases. Also, purified recombinant cystatin A was found to have identical amino acid composition, NH2-terminal amino acid sequence, and peptide-map on reverse phase HPLC with those of the authentic inhibitor.

Base Sequence↗
PubMed1989

Comparative studies on the primary structure of human cystatin as from epidermis, liver, spleen, and leukocytes.

We have studied the primary structure of human cystatin As from epidermis, liver, spleen, and leukocytes. These molecules were indistinguishable on PAGE in the presence and absence of SDS, by fast protein liquid chromatography (FPLC) chromatofocusing on a Mono P column, and in amino acid composition. The NH2- and COOH-terminal amino acid sequences of human cystatin As from epidermis, liver, and spleen were identical with those of human leukocyte cystatin A previously reported except for the lack of the NH2-terminal methionine residue in human epidermal cystatin A. The peptides obtained upon digestion of four human cystatin As with Achromobacter protease I (AP) showed identical peptide maps on HPLC except for different retention times of the NH2-terminal peptides. Furthermore, the amino acid compositions of corresponding separated peptide quartets were identical. We also determined the complete amino acid sequence of human epidermal cystatin A by sequencing peptides obtained from AP digestion and cyanogen bromide (CNBr) cleavage. It consisted of 97 amino acid residues, and was identical with those of human cystatin As from liver, spleen, and leukocytes except for the lack of the NH2-terminal methionine residue.

Amino Acid Oxidoreductases↗
PubMed1989

Characterization of copper atoms in bilirubin oxidase by spectroscopic analyses.

Bilirubin oxidase [EC 1.3.3.5], purified from the culture medium of Myrothecium verrucaria, was found to contain two blue copper atoms per protein molecule with a molecular weight of ca. 52 kDa. The two copper atoms were estimated to be in the all cupric state by the cuproine colorimetric method and also atomic absorption analysis. We could remove the reduce cuprous ions from the holo enzyme by adding ascorbate, followed by a KCN solution, yielding an apo-enzyme with no activity. The apo-enzyme can be reconstituted with Cu or other divalent cations such as Co, Fe, and Cd, with accompanying recovery of the enzyme activity. The activity recovery depended upon the species of cation employed; Cu being most effective, an almost 100% recovery, and Cd the least, only a 25% recovery. We could obtain information on the copper ions and their coordination structure by spectroscopic analyses of the apo- and reconstituted enzymes, obtaining such as absorption, CD, MCD, and XPS spectra. The bilirubin oxidase catalyzed-reaction was a second order reaction with respect to copper bound with protein. The donor set was of the CuSS*N2 (S = Cys, S* = Met, N = His) type, i.e., the same as in the case of blue copper proteins. On studying the Co-substituted enzyme, it was revealed that the copper site of the enzyme had a 4-coordinated structure.

Apoproteins↗
PubMed1989

Attenuation of thyroid hormone action by 1,25-dihydroxyvitamin D3 in pituitary cells.

Interactions between thyroid hormone and 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] were examined in a rat pituitary tumor cell line, GH4C1. Cells were incubated in thyroid hormone-depleted medium for 2 days, and specific nuclear binding of [125I]T3 was measured. 1,25-(OH)2D3 decreased nuclear [125I]T3 binding without changing total cellular uptake of [125I]T3. This 1,25-(OH)2D3 effect required 2-3 h to become evident and 24 h to reach a maximum (40-50% of control) and was reversible. Treatment with 1,25-(OH)2D3 for 8 h changed the maximal binding capacity for [125I]T3 from 80.2 +/- 2.9 to 50.3 +/- 6.3 fmol/10(6) cells, whereas Kd was not significantly altered. The decrease in [125I]T3 binding was dose dependent, with an IC50 for 1,25-(OH)2D3 of 1 nM in thyroid hormone-depleted medium. 1,25-(OH)2D3 caused little change in [125I]T3 binding to isolated nuclei, i.e. 1,25-(OH)2D3 does not compete directly with [125I]T3 for binding. It is unlikely that 1,25-(OH)2D3 decreased [125I]T3 binding by increasing the concentration of intracellular free calcium ([Ca2+]i), since 1,25-(OH)2D3 did not change [Ca2+]i in Indo-I-loaded GH4C1 cells. Two major species (6 and 2.6 kilobases) of mRNA for c-erb-A, which have been reported to encode nuclear thyroid hormone receptors, were found by Northern blot analysis, and both were decreased by treatment with 1,25-(OH)2D3 for 8 h. T3 (2 nM) caused a 3-fold increase in GH production over 72 h and 1,25-(OH)2D3 inhibited GH induction by T3, with an IC50 at approximately 1 nM. 1,25-(OH)2D3 stimulated PRL synthesis 5-fold when 10 nM T3 was present, but not when T3 was absent. In summary, 1,25-(OH)2D3 caused a dose-dependent down-regulation of nuclear thyroid hormone receptors at a pretranslational level and diminished GH induction by T3. These results suggest that 1,25-(OH)2D3 inhibits GH synthesis indirectly, at least partly, by attenuating endogenous thyroid hormone action.

Animals↗