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Biomedical subjects

K Hitomi

Publications and source records attributed to K Hitomi.

At least 55 records · Page 3Linked to original sources
PubMed1994

L-ascorbic acid 2-phosphate promotes osteoblastic differentiation of MC3T3-E1 mediated by accumulation of type I collagen.

L-Ascorbic acid 2-phosphate (Asc-P: a stable ascorbic acid derivative) markedly stimulated synthesis of marker proteins for osteoblastic differentiation such as alkaline phosphatase and osteocalcin in a murine osteoblastic cell line, MC3T3-E1, suggesting that Asc-P could promote osteoblastic differentiation. L-Azetidine 2-carboxylate (AzC) diminished the stimulatory effects of Asc-P on the synthesis of alkaline phosphatase and osteocalcin due to its inhibitory effects on mature collagen secretion. Growing cells on the dishes coated with type I collagen resulted in an increased expression of osteoblastic phenotypes even in the presence of AzC. Coating with fibronectin, however, failed to promote differentiation. These results suggest that the promotion of cell differentiation caused by Asc-P is mediated by the accumulation of mature collagen.

Alkaline Phosphatase↗
PubMed1993

Ascorbate-dependent elevation of mRNA levels for cytochrome P450s induced by polychlorinated biphenyls.

Trichlorobiphenyl induced only CYP1A2 mRNA, while pentachlorobiphenyl induced both CYP1A2 and CYP2B1 mRNAs in rat liver. The mRNA levels for these P450s were elevated when ascorbic acid-deficient ODS rats (mutant rats with a hereditary osteogenic disorder) were fed a diet supplemented with ascorbic acid. The amount of CYP2B1 mRNA increased rapidly and reached a maximum level of approximately double within 24 hr of injection of pentachlorobiphenyl. Thereafter, the amount of its mRNA decreased to a steady level. This pattern was roughly paralleled by changes in the amount of CYP1A2 mRNA.

Animals↗
PubMed1993

[Two cases of tension pneumothorax caused by tracheal suction during the operation of pectus excavatum].

Rehbein's method is one of the surgical procedures for pediatric pectus excavatum, which constructs thorax by lifting and fixating the sternum using metal strut inserted into bone marrow of bilateral ribs. We experienced two pediatric cases of tension pneumothorax caused by tracheal suctioning during the operation by this method. The etiology of tension pneumothorax was thought to be as follows. A small pleural hole was made during separation of ribs from surrounding tissues and a large amount of air entered into the pleural space and check valve mechanism worked at the pleural hole when the lung was collapsed on tracheal suctioning. In anesthetic management of pectus excavatum by Rehbein's method, we should always be cautious of the possible occurrence of tension pneumothorax.

Child↗
PubMed1992

Increase in the activity of alkaline phosphatase by L-ascorbic acid 2-phosphate in a human osteoblast cell line, HuO-3N1.

The activity of alkaline phosphatase (ALPase) was significantly enhanced in a human osteoblast cell line, HuO-3N1, when it was cultured in the presence of L-ascorbic acid 2-phosphate (AsA-P; a stable ascorbic acid derivative). With AsA-P in the culture, the level of ALPase activity increased approximately 3-fold without any effect on either the morphology or growth rate. This increase was dependent on the AsA-P concentration in the range of 0.2-2 mM and required at least 48 h incubation with AsA-P. The ALPase mRNA level, however, remained rather constant irrespective of the enzyme activity. Removal of AsA-P from the precultured medium decreased the stimulatory effect of ascorbic acid on the ALPase activity, indicating that the effect was reversible. Dexamethasone, an inducer for osteoblastic differentiation, enhanced the level of ALPase activity irreversibly, in parallel with the increase in the level of its mRNA. The enhancement of the ALPase activity by ascorbic acid in this cell line appeared to be independent of cell differentiation.

Alkaline Phosphatase↗
PubMed1990

Establishment of an erythroid cell line (JK-1) that spontaneously differentiates to red cells.

The authors established a new hemopoietic cell line (JK-1) from a patient with chronic myelogenous leukemia in erythroid crisis. This JK-1 line predominantly consists of immature cells, but a small number of mature erythroblasts and red cells can be consistently seen without any specific differentiation inducer. The JK-1 cells grow in suspension culture supplemented with human plasma and carry double Philadelphia chromosomes. Hemoglobin staining with benzidine was positive for about 20% of cells and the type of the hemoglobin was for the most part HbF. Surface-marker analysis revealed JK-1 cells positive for glycophorin A, EP-1, and HAE9. The proportion of mature cells was elevated by the addition of delta-aminolevulinic acid. Erythropoietin (EPO) enhanced the growth of JK-1 cells either in the suspension or in methylcellulose semisolid culture. The total number of EPO receptors was 940 per cell, of which 220 sites had an affinity higher than the other 720 sites. This is the first report of an established human erythroid cell line which spontaneously undergoes terminal differentiation.

Antigens, Surface↗
PubMed1990

Expression of the erythropoietin receptor on a human myeloma cell line.

We demonstrated the expression of the erythropoietin (EPO) receptor by a human myeloma cell line (MM-S1) which was established in our laboratory. EPO dose-dependently stimulated the proliferation of MM-S1 cells. Binding of radioiodinated EPO (125I-Epo) to MM-S1 cells was competitively inhibited by unlabeled EPO, but not by other recombinant cytokines. Specific binding of 125I-Epo to MM-S1 cells was saturable, and the Scatchard analysis revealed 330 EPO binding sites per cell with a Kd of 0.56 nmol/L. Bound EPO was internalized by MM-S1 cells during incubation at 37 degrees C. This is the first report describing the expression of the EPO receptor by human cells other than those of the erythroid lineage.

Cell Division↗
PubMed1989

Solubilization and characterization of erythropoietin receptor from transplantable mouse erythroblastic leukemic cells.

Functional erythropoietin (Ep) receptor (Ep-R) on transplantable mouse leukemic cells was solubilized by 3[(3-cholamidopropyl)dimethyl ammonio]-1-propanesulfate (CHAPS). An assay of the solubilized Ep-R was established: (1) radioiodinated Ep was bound to the solubilized Ep-R, (2) Ep.Ep-R complexes were covalently cross-linked, (3) the cross-linked products were selectively precipitated by polyethylene glycol, (4) the products were separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and (5) the Ep.Ep-R cross-linked products were measured. Optimal conditions to yield the cross-linked products and to stabilize the solubilized Ep-R were found. The solubilized Ep-R had properties similar to those of Ep-R on the membrane with respect to binding with Ep and the cross-linked products. These results would be exploited to allow purification of Ep-R.

Animals↗
PubMed1988

Erythropoietin receptor of a human leukemic cell line with erythroid characteristics.

A new cell line of human erythroleukemia cells differentiates spontaneously so that 30% of the cells are always hemoglobinized. Erythropoietin did not affect the percentage of such cells but stimulated the cell growth, indicating that the cells have functioning receptors. Binding of human recombinant radioiodinated erythropoietin to the receptors was specific. The bound ligand was internalized into cells at 37 degrees C but not at 15 degrees C. Scatchard analysis showed two classes of binding sites. Covalent binding of erythropoietin to its receptors yielded two products detected on sodium dodecyl sulfate-polyacrylamide gels electrophoresed under reducing conditions. Under non-reducing conditions, these species disappeared and larger products appeared.

Cell Differentiation↗
PubMed1988

Stromal cell-dependent growth of leukemic cells from murine erythroblastic leukemia.

Transplantable erythroblastic leukemia was induced by 300-rad irradiation of C3H mice. Conditions for in vitro growth of the leukemic cells were studied. None of interleukin-3, granulocyte/macrophage colony-stimulating factor and erythropoietin could support the growth of the cells in vitro. In contrast, the leukemic cells grew into a stroma-dependent cell line, ELM-D, in close contact with the stromal cell layer of 900-rad-irradiated long-term bone marrow culture. A stroma-independent cell line, termed ELM-I-1, was further established from the non-adherent population in the co-culture of the leukemic cells, ELM-D, with stromal cells. Reverse transcriptase activity was not detectable in ELM-D or ELM-I-1 cells. Studies on binding and cross-linking of 125I-erythropoietin showed that ELM-I-1 cells had erythropoietin receptors, and two major radiolabeled protein products with molecular weights of 120 kDa and 140 kDa were detected on sodium dodecyl sulfate/polyacrylamide gel electrophoresis under reducing conditions.

Animals↗
PubMed1987

Characterization of erythropoietin receptor of murine erythroid cells.

Radioiodinated or biologically tritiated recombinant human erythropoietin was used to characterize receptors for this hormone on the surface of Friend erythroleukemic cells (745A and TSA8) and cells from mouse erythropoietic tissues (liver from fetus and spleen from animals made anemic by injection of Friend virus or phenylhydrazine). Specific binding of erythropoietin to these cells was time-dependent and dose-dependent. Binding studies at 37 degrees C showed that dissociation constants of erythropoietin-receptor complexes were in the range of 100-300 pM. The number of receptors on erythroleukemic cells increased after treatment with dimethylsulfoxide. Covalent binding of 125I-erythropoietin to its receptors with a cross-linking reagent, disuccinimidyl suberate or glutaraldehyde, resulted in the formation of two major radiolabeled products that migrated as 120-kDa and 140-kDa species on sodium dodecyl sulfate/polyacrylamide electrophoresis gels under reducing conditions. Under non-reducing conditions, both 120-kDa and 140-kDa species disappeared and two cross-linked products, a minor product with a molecular mass of 250 kDa and a major product of high molecular mass that kept it from migration into the separating gels, appeared. The relationship of the cross-linked products found under non-reducing conditions with those under reducing conditions remains to be clarified.

Animals↗
PubMed1987

Human kidney glomeruli, with special reference to those in the aged person: scanning electron microscopic study of microvascular corrosion casts.

Blood vascular beds of fetal, adult and aged human kidneys were reproduced with methyl methacrylate and observed with a scanning electron microscope. The kidney glomeruli, including those from the fetal kidneys, had anastomosing capillaries. The glomeruli in the kidneys of an aged person contained many more capillaries which were much more tortuous than those of the adult and fetal kidneys. Furthermore, it was observed that the glomeruli in the kidneys of the aged person usually received tortuous afferent vessels and frequently emitted multiple efferent arterioles. The glomeruli in the juxtamedullary layer of the kidneys of the aged person were rather small in size and contained degenerative capillary networks. This observation suggests that the medulla of the kidneys of the aged is poorly supplied with blood.

Adult↗
PubMed1986

Isolation and characterization of cDNA encoding rabbit reticulocyte 2,3-bisphosphoglycerate synthase.

We have isolated and sequenced a cDNA clone containing the entire coding region of rabbit reticulocyte 2,3-bisphosphoglycerate (DPG) synthase. The cDNA was verified by translation of the hybridization-selected RNA and by demonstrating identity of the deduced amino acid (aa) sequence to the sequences of CNBr peptides of the purified enzyme. The aa sequence of the enzyme was homologous to the reported sequence of the human enzyme [Haggarty et al., EMBO J. 2 (1983) 1213-1220], especially in the N-terminal half (aa 1-142). Northern blot analysis of rabbit reticulocyte poly(A)+ RNA revealed a single species of mRNA with about 1700 nucleotides.

Amino Acid Sequence↗
PubMed1985

Inter-rater reliability of the Comprehensive Psychopathological Rating Scale in Japan.

In order to apply the Comprehensive Psychopathological Rating Scale (CPRS) to psychiatric clinical practice in Japan we have made a preliminary Japanese version and examined the doctor to doctor and doctor to nurse inter-rater reliability. Compared with the high reliability of the items of reported psychopathology, the coefficients of correlation of observed psychopathology were considerably scattered. Education and training of the rater may improve the reliability. It is considered that the CPRS will become a very useful psychiatric rating scale in Japan.

Adolescent↗
PubMed1985

Intrathymic T cell differentiation in radiation bone marrow chimeras and its role in T cell emigration to the spleen. An immunohistochemical study.

Immunohistochemical studies were made on the regeneration of T cells of host- and donor-type in the thymus and spleen of radiation bone marrow chimeras by using B10- and B10.BR-Thy-1 congenic mice. Both the thymic cortex and the medulla were first repopulated with thymocytes of irradiated host origin, restoring the normal histologic appearance by days 11 to 14, regardless of the H-2 compatibility between the donor and the host. In Thy-1 congenic chimeras, thymocytes of donor bone marrow origin, less than 100 cells in one thymic lobe, were first recognized at day 7, when the thymus involuted to the smallest size after the irradiation. The thymocytes of donor-type then proliferated exponentially, showing a slightly faster rate when higher doses of bone marrow cells were used for reconstitution, reaching a level of 100 million by day 17 and completely replacing the cortical thymocytes of host origin by day 21. The replacement of cortical thymocytes started from the subcapsular layer in a sporadic manner. The replacement of medullary thymocytes from host- to donor-type occurred gradually between days 21 and 35, after the replacement in the cortex was completed. In the spleen, about 1 million survived cells were recovered at day 3 after the irradiation, and approximately 60% of them were shown to be host-type T cells that were observed in the white pulp areas. The host-type T cells in the spleen increased gradually after day 10, due to the influx of host-type T cells from the regenerating thymus. Thus a pronounced increase of T cells of host-type was immunohistochemically observed in the splenic white pulp between days 21 and 28, when thymocytes of host-type were present mainly in the thymic medulla. These host-type T cells were shown to persist in the spleen for a long time, as long as 420 days after the treatment. Phenotypically, they were predominantly Lyt-1+2+ when examined at day 28, but 5 mo later, they were about 50% Lyt-1+2+ and 50% Lyt-1+2-. Donor-type T cells in the spleen began to appear at about day 14 in chimeras that were transplanted with a larger dose of bone marrow cells, whereas this was slightly delayed in those grafted with a smaller dose of bone marrow cells, starting at about day 28.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1984

A monomeric methyl and hydroxypropyl methacrylate injection medium and its utility in casting blood capillaries and liver bile canaliculi for scanning electron microscopy.

A mixture of 50-60% monomeric methyl methacrylate and 40-50% monomeric 2-hydroxypropyl methacrylate was supplemented with 1.5% benzoyl peroxide (catalyst) and 1.5% N,N-dimethylaniline (accelerator) and injected into glutaraldehyde-perfusion fixed rat hypophyseal and other endocrine organ blood vessels and biliary tracts. This injection medium rapidly polymerized at room temperature and did not require partial polymerization prior to injection. Good casts of blood vessels, including the hypophyseal capillaries, were obtained for scanning electron microscopy. The monomeric methacrylate medium possesses a great advantage over previous ones, as its fluidity enables the casting of very fine vessels such as bile canaliculi. In the case of non-fixed tissues, the monomeric methacrylate medium should be injected carefully, as it is toxic and destructive to the vessels.

Acrylates↗