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Biomedical subjects

S Kitajima

Publications and source records attributed to S Kitajima.

At least 145 records · Page 8Linked to original sources
PubMed1990

[Establishment and characterization of a human malignant fibrous histiocytoma cell line (K-MFH-1)].

We established and characterized a cell line (K-MFH-1) of human malignant fibrous histiocytoma in vitro and in nude mice. The cells have been kept in culture for nearly 4 years in 121 subcultures in vitro and transferred serially in nude mice in 10 generations. The original tumor histology was epithelioid, angiomatoid variant of MFH, but cells in culture showed a variety of morphology. Chromosomal study disclosed that this tumor was monoclonal in origin. Electron microscopic study revealed that cells had some epithelial characteristics as well as histiofibroblastic features. Tumor cell morphology gradually shifted from epithelioid to myxomatous fibroblastic forms after serial transplantations in nude mice. Some tumors showed an extensive vascular proliferation like angioma suggesting that tumor cells have released angiogenic factors.

Animals↗
PubMed1990

Cutaneous carcinoma and 8-methoxypsoralen and ultraviolet A (PUVA) lentigines in Japanese patients with psoriasis treated with topical PUVA: a follow-up study of 214 patients.

A total of 214 Japanese patients with psoriasis, under treatment with topical 8-methoxypsoralen and ultraviolet A (PUVA), were examined for malignant skin tumors and pigmented lesions during a follow-up period of up to 17 years (mean 5.8 years). One patient had developed multiple superficial basal cell carcinomas, and the remaining 213 patients had neither cutaneous carcinomas nor actinic keratoses. PUVA lentigines were seen in 89 patients (42%) and the incidence of lentigines increased as the number of PUVA treatments and the cumulative UVA dose increased. Melanocytic atypia was not observed histologically in 24 pigmented lesions examined. This report suggests that this topical PUVA regimen may not be highly carcinogenic in the Asian population.

Adolescent↗
PubMed1990

Pathoepidemiological features of adult T-cell lymphoma/leukemia in an endemic area: Kagoshima, Japan.

In order to elucidate the pathological and epidemiological features of malignant lymphoma (ML), particularly of adult T-cell lymphoma/leukemia (ATLL) in the Kagoshima district, age-adjusted and age-specific incidence rates of malignant lymphomas were estimated on 3239 histologically confirmed cases between the years 1963 and 1987. There was a marked increase in the incidence rate from 1976 (4.9) to 1982 (8.5) due to the increase of T-cell lymphomas. The increase was not conspicuous after 1982. Immunohistochemically, all of the 429 MLs found in 1985 and 1986 were examined on paraffin sections and 70 ATLL cases on fresh frozen sections. T-cell ML comprised 65.3%, B-cell ML 30.5%, Hodgkin disease 2.6%, and histiocytic ML 1.2%. Most of ATLL cells were phenotypically CD4+ CD8-, 14% of ATLL cases showed CD4+ CD8+, 6% were CD4- CD8+, and 7% were CD4- CD8-. The simulataneous expression of IL 2 and IL 2R was seen in 8 (16%) out of 56 patients examined. Therefore, a proliferation by autocrine mechanism does not seem to be a major course of ATLL progression.

Age Factors↗
PubMed1989

Resolution and partial characterization of factors required for in vitro transcription by mammalian RNA polymerase II.

Multiple protein factors from HeLa cells are necessary for the accurate initiation of transcription on minimal promoters in vitro. We have partially purified these factors by chromatographic methods. In addition to RNA polymerase II, six factors A-F (FA, FB, FC, FD, FE, and FF) necessary for initiation at the beta-globin promoter start site in vitro have been identified. Certain of these (FA, FC, and FE) have been purified to near homogeneity. The present purification scheme yields sufficient amounts of purified material for the more detailed characterization and cloning of the genes for these activities. Among these factors, FD and FF were required with template DNA at an early step of formation of the initiation complex, whereas FB, FA together with FC, and FE were effective when added at successively later stages in the process of complex formation.

Cell Nucleus↗
PubMed1989

Glycosaminoglycan composition of PC12 pheochromocytoma cells: a comparison with PC12D cells, a new subline of PC12 cells.

PC12D cells, a new subline of conventional PC12 cells, respond not only to nerve growth factor but also to cyclic AMP by extending their neurites. These cells are flat in shape and are similar in appearance to PC12 cells that have been treated with nerve growth factor for a few days. In both cell lines, we have characterized the glycosaminoglycans, the polysaccharide moieties of proteoglycans, which are believed to play an important role in cell adhesion and in cell morphology. Under the present culture conditions, only chondroitin sulfate was detected in the media from PC12 and PC12D cells, whereas both chondroitin sulfate and heparan sulfate were found in the cell layers. The levels of cell-associated heparan sulfate and chondroitin sulfate were about twofold and fourfold higher in PC12D cells than in PC12 cells, respectively. Compared to PC12 cells, the amounts of [35S]sulfate incorporated for 48 h into chondroitin sulfate were twofold lower but those into heparan sulfate were 35% higher in PC12D cells. The amount of chondroitin sulfate released by PC12D cells into the medium was about a half of that released by PC12 cells. The ratio of [35S]sulfate-labeled heparan sulfate to chondroitin sulfate was 6.2 in PC12D cells and 2.2 in PC12 cells. These results suggest that there may be some correlation between the increase in content of glycosaminoglycans and the change in cell morphology, which is followed by neurite outgrowth.

Adrenal Gland Neoplasms↗
PubMed1989

Synergistic enhancement of class I major histocompatibility complex antigen expression in K562 cells induced by recombinant human interferon-gamma and tumor necrosis factor in combination.

The effects of recombinant preparations of human interferon-gamma (rIFN-gamma) and tumor necrosis factor (rTNF), alone or in combination, on class I or class II major histocompatibility complex (MHC) antigen induction were studied using K562, a multipotent hematopoietic precursor cell line. Class I antigens were weakly induced by rIFN-gamma; however, rTNF at any concentration examined (1-1000 U/ml) showed no effect on the induction of class I or class II antigens in the cells. rIFN-gamma (600 U/ml) induced approximately 20% of the cells to express class I antigens after 72-h exposure, whereas 81% of the cells demonstrated class I antigens on their cell surfaces when the cells were simultaneously exposed to 600 U/ml of rIFN-gamma and 1000 U/ml of rTNF. The class II MHC antigens were not induced by the treatments with rIFN-gamma or rTNF, alone or in combination. A synergistic increase of mRNA for class I MHC molecules was demonstrated by treatments of the cells with rIFN-gamma and rTNF in combination. rTNF, but not rIFN-gamma, weakly induced granulocyte-monocyte antigens on the cell surface; however, no synergism was observed on the induction of these antigens by the combined treatments with rIFN-gamma and rTNF. These results indicate that class I MHC antigen expression on K562 cells can be induced by IFN-gamma in cooperation with TNF in a manner different from myeloid antigen expression.

Dose-Response Relationship, Drug↗
PubMed1988

[Calmodulin and neuron: immunohistochemical studies].

Calmodulin is present in higher concentrations in brain tissues. The content rapidly increased during the 2nd postnatal week in rat brain. Although the protein is ubiquitous in all eukaryotic cells, immunohistochemical studies have revealed that calmodulin is mainly localized in the neurons, exhibiting a similar distribution to that of gamma-type neuron-specific enolase. In the mouse retina, both calmodulin and gamma-enolase were found to be localized in optic nerves, ganglion cells, and inner and outer plexiform layers. The development study showed that gamma-enolase increased in the 2nd postnatal week and that the levels of calmodulin did not significantly change in that stage. In the mouse retina with an inherited retinal dysplasia (C3H), in which all the photoreceptor cells degenerate during the 2nd and 3rd postnatal weeks, calmodulin-specific staining decreased in the residual layers. Calmodulin is also enriched in mammalian testes. In the mouse testis, levels of calmodulin were high in the spermatocytes and in the spermatids, as compared to the level in spermatozoa. This suggests that the large amount of calmodulin in the testis may be associated with miotic divisions and/or spermatogenesis. Immunocytochemical staining of calmodulin in C6 glioma cells and PC12 pheochromocytoma cells showed a high level of calmodulin to be localized on the half spindles between poles and chromosomes in mitotic cells. The protein was also shown to be localized on fibrous structures in the interphase of those cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

The effect of axotomy and denervation on calmodulin content in the superior cervical sympathetic ganglion of the rat.

Calmodulin (CaM) in the superior cervical sympathetic ganglion (SCG) of the rat and its changes after transection of the pre- or postganglionic nerves were studied biochemically and immunohistochemically. The concentration of CaM in the SCG was assayed using the extent of activation of CaM-dependent adenylate cyclase from bovine neural retina. In the SCG, CaM concentration was 4.5 micrograms/mg protein, a level similar to that in another peripheral ganglion, the nodose ganglion (4.9 micrograms/mg protein). Following denervation of the SCG, the total amount of ganglionic CaM did not change significantly within a week. On the other hand, CaM content per ganglion increased gradually 3 days after axotomy. Immunohistochemical examination revealed that CaM in unoperated SCG is present both in the neuronal fibers and in the cell soma of sympathetic neurons. But the intensity of the staining with CaM-antibody in the cytoplasmic soma varied among cells. The gross profile of the CaM immunostaining seemed to be unchanged one week after either denervation or axotomy, but the immunoelectron microscopic study showed heavy staining of the innercellular membranes of irregular shape in the axotomized SCG.

Adenylyl Cyclases↗
PubMed1987

Immunohistochemical study of calmodulin in developing mouse testis.

The purpose of this study was to determine the localization of calmodulin in the developing mouse testis by the indirect immunoperoxidase method. In addition, the amount of calmodulin in pachytene spermatocytes, spermatids, and residual bodies isolated from the mouse testis and epididymal spermatozoa was quantitated by the adenylate cyclase activation assay and by enzyme immunoassay. The relative levels of calmodulin in the developing mouse testis and in the isolated testicular germ cells were confirmed by western transfer staining. The level of immunoreactive calmodulin was very low in the testes from immature animals. In testes from the mature mouse, calmodulin was found to be localized in spermatocytes and spermatids, but was not found in spermatogonia, Sertoli cells, and interstitial cells. By contrast, immunochemical staining of tubulin was extremely intense in Sertoli cells. Biochemical determinations also showed that pachytene spermatocytes, round spermatids, spermatozoa, and residual bodies contained 14.9 micrograms, 15.8 micrograms, 2.3 micrograms and 5.2 micrograms of calmodulin per mg of protein, respectively. Both the immunochemical and the biochemical studies revealed that levels of calmodulin were high in the spermatocytes and in the round spermatids, as compared to the level in spermatozoa. This fact strongly suggests that the large amount of calmodulin in mammalian testes may be associated primarily with meiotic divisions and/or spermatogenesis.

Aging↗
PubMed1987

Neuritic growth from a new subline of PC12 pheochromocytoma cells: cyclic AMP mimics the action of nerve growth factor.

We have identified a new subline of PC12 pheochromocytoma cells (PC12D cells) in which neurites are extended within 24 hr in response to cAMP-enhancing reagents as well as in response to nerve growth factor (NGF), but not in response to epidermal growth factor or phorbol diester. Anti-NGF antiserum did not affect forskolin (FRK)-induced neuritic recruitment. FRK-induced neurites exhibited growth cones and contained secretion granules and many parallel arrays of microtubules as was the case with NGF-induced neurites. FRK, but not NGF, increased the levels of intracellular cAMP and activated adenylate cyclase in the membrane fraction. Both NGF and FRK enhanced the activities of tyrosine hydroxylase (TH), acetylcholinesterase (AchE), and ornithine decarboxylase (ODC), but not the levels of neuron-specific enolase. Enhanced levels of intracellular cAMP mimicked the effects of NGF on neuritic growth, TH, AchE, and ODC activities in PC12D cells, even though NGF does not act through elevation of levels of cAMP.

Adenylyl Cyclases↗
PubMed1987

The early expression of immunoreactivity for calmodulin in the nervous system of mouse embryos.

Calmodulin (CaM) is a major calcium-binding protein in the brain, where its immunoreactivity is mainly localized in the neurons. In this study, ontogenical changes in the distribution of CaM in the nervous system of mouse embryos were investigated immunohistochemically using a specific antibody against CaM and an indirect immunoenzyme method. Immunoreactive staining was first observed in the marginal layer of the cranial neural tube after 9.5 days of gestation; thereafter, the amount of stained structures increased rapidly. Particularly intense staining was observed in the long neuronal processes extending from or into the brain and spinal cord primordia. Intense immunostaining was also observed in the optic nerve layer of early retinae from 12.5 days of gestation. The appearance of CaM immunoreactivity is thus an early event during neuronal differentiation, apparently concomitant with the initiation of axon extension and the appearance of neurofilament proteins.

Animals↗
PubMed1987

[Reproduction study of rokitamycin. Teratological study in rabbits].

A teratological study was performed on rokitamycin (TMS-19-Q), a new macrolide antibiotic, using rabbits. TMS-19-Q, at dose levels of 100, 300 and 600 mg/kg, was orally administered from the day 6 to the day 18 of gestation to dams. Diarrhea and decrease in body weight gain and food consumption were observed in dams at or above 300 mg/kg. Decrease in numbers of live fetuses was observed at dose levels of 300 and 600 mg/kg but there was no teratogenicity at any dose levels. The maximum non-toxic dose level for TMS-19-Q in this study was 100 mg/kg.

Abnormalities, Drug-Induced↗
PubMed1986

Interaction of GTP-binding proteins with calmodulin.

Two GTP-binding proteins (Gi and Go), which were the substrates for islet-activating protein, pertussis toxin, were purified from bovine cerebral cortical membranes. Both Gi and Go completely inhibited calmodulin-stimulated cyclic nucleotide phosphodiesterase activity. The same concentrations of these proteins, however, had no appreciable effect on the basal phosphodiesterase activity. The isolated Gi alpha and beta gamma subunits of GTP-binding proteins were potent inhibitors of the calmodulin-stimulated phosphodiesterase activity, but Go alpha was very weak. Therefore, the beta gamma subunits were likely to be the major active molecules in the brain membranes. GTP-binding proteins were shown to bind directly to calmodulin in a Ca2+-dependent manner by a gel permeation binding experiment.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1986

Ultracytochemistry of pancreatic damage induced by excess lysine.

The ultracytochemical changes induced in the pancreas by a single large dose of lysine (400 mg/100 g body weight) were studied in male Wistar rats of 7 weeks old. The first changes in the acinar cells were marked swelling of mitochondria with increase in their calcium content and decrease in their ATP content. Early calcium deposits seemed to occur in the matrices of swollen mitochondria and later various patterns occurred. These findings suggested that damage of the acinar cells by excess lysine resulted in breakdown of the mitochondrial membrane barrier to calcium as a very early abnormality, and that extracellular calcium then entered the mitochondrial matrices and inhibited mitochondrial function. Subsequently focal areas of the cytoplasm were degraded. Autophagic vacuoles appeared in these areas, and then acid phosphatase activity in their periphery as a result of fusion with lysosomes. The reaction of acid phosphatase was demonstrated in the locally degraded rough endoplasmic reticulum within or around autophagic vacuoles, suggesting that the endoplasmic reticulum as well as lysosomes participated in the intracellular degradation of cytoplasmic organelles in damaged acinar cells.

Acid Phosphatase↗
PubMed1985

Effect of modification of lysine residues of fructose-6-phosphate 2-kinase:fructose-2,6-bisphosphatase with pyridoxal 5'-phosphate.

Inactivation of a bifunctional enzyme, fructose-6-P,2-kinase:fructose-2,6-bisphosphatase by pyridoxal 5'-P followed by reduction with NaBH4 was studied. Fructose-6-P,2-kinase is over 80% inactivated by 2 mM pyridoxal 5'-P. The stoichiometry of the pyridoxyl-P incorporation and the inactivation of the kinase follows a biphasic curve. The first P-pyridoxyl residue incorporated per protomer does not affect fructose-6-P,2-kinase, but the next two P-pyridoxyl incorporation/protomer results in 80% inactivation. The Km values for ATP and fructose-6-P of the enzymes containing varying amounts of P-pyridoxyl groups at intermediate levels of inactivation are not altered, but Vmax is decreased. Among the metabolites tested, only fructose-2,6-P2 and Mg-ATP are competitive with pyridoxal-P and protect the enzyme against the inactivation. Neither the activity nor the fructose-6-P inhibition of fructose-2,6-bisphosphatase is affected by the modification. The acid hydrolysate of the inactive P-[3H]pyridoxyl enzyme contained only [3H]pyridoxyl lysine. High performance liquid chromatography of tryptic peptides of phospho[3H]pyridoxyl enzymes reveals two peptides which were missing in the enzyme protected by fructose-2,6-P2 or ATP during the modification reaction. These peptides have been isolated, and their amino acid sequences have been determined as Asp-Gln-Asp-Lys-Tyr-Arg and Asp-Val-His-Lys-Tyr. Pyridoxal-P reacts specifically with two lysine residues at the fructose-2,6-P2-binding site of fructose-6-P,2-kinase but not that of fructose-2,6-bisphosphatase. The site may also overlap with the ATP-binding site.

Adenosine Triphosphate↗
PubMed1985

Ultrastructure of tumor cell interaction with alveolar macrophages stimulated by vitamin A.

F344 rats were given vitamin A for four consecutive days and then their alveolar macrophages (AM phi) were obtained by bronchopulmonary lavage of the lung. Compared with unstimulated AM phi, AM phi from rats given vitamin A had more numerous and longer cytoplasmic projections, and these projections had many knobs on their sides and tip. The AM phi became attached to syngeneic mammary adenocarcinoma cells at many focal points and the tumor cells then lost surface microvilli around the contact zones. Detachment of the knobs from the projections on AM phi was often observed in areas of close association between AM phi and tumor cells. The detached knobs were 250 nm in diameter, gave a positive reaction for acid phosphatase, and frequently became attached to the surface of tumor cells. Then, many of the tumor cells in the vicinity of AM phi exhibited cytolytic changes. It is concluded that the cytotoxicity of stimulated AM phi is due to their attachment to the surface of tumor cells and their release of particles with acid phosphatase activity into the narrow space between the cells, and then to uptake of these particles by susceptible tumor cells.

Animals↗