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Biomedical subjects

K Kohno

Publications and source records attributed to K Kohno.

At least 37 records · Page 2Linked to original sources
PubMed1992

The immunomodulatory role of IFN-alpha or maltose-stabilized IFN-alpha on T-cell activation.

The effects of human interferon-alpha (IFN-alpha) or maltose-stabilized IFN-alpha (MS-IFN-alpha) on IL-2 production by PHA- or anti-CD3 mAb-stimulated MOLT 16 cells, a human leukemic T cell line, were studied. MS-IFN-alpha is an IFN-alpha-containing powder in which maltose was used as an excipient, and has been shown to have a positive effect on human immunodeficiency virus (HIV)-infected patients. In this study, MS-IFN-alpha powder was dissolved in a culture medium and used for the experiments. IL-2 production by PHA- or anti-CD3 mAb-stimulated MOLT 16 cells was augmented by coculturing with IFN-alpha or MS-IFN-alpha. The augmentation of IL-2 production by IFN-alpha or MS-IFN-alpha was completely abrogated by rabbit anti-IFN-alpha antibody. We have previously shown that IL-2 production by PHA-stimulated MOLT 16 cells is augmented by coculturing with IL-1. Furthermore, IL-2 production by PHA-stimulated MOLT 16 cells was also augmented by human TNF-alpha in a dose-dependent manner. The TNF-alpha-induced augmentation was completely abrogated by rabbit anti-TNF-alpha antibody. Interestingly, both IFN-alpha and MS-IFN-alpha synergized with rIL-1 alpha or TNF-alpha resulting in IL-2 production being augmented far more effectively than either cytokine alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1992

[Cervical spinal cord injury caused by a broken acupuncture needle: a case report].

Spinal cord injury is a rare but considerable complication of acupuncture. A case with cervical spinal cord injury caused by a broken acupuncture needle was reported and sixteen previously reported cases including our case were reviewed. A 49-year-old woman was treated by herself with acupuncture on the nuchal region for occipitalgia, and the needle was accidentally broken during the treatment. Six hours later she noticed pain and numbness in the right upper and lower extremities. Neurological examination revealed slight impairment of temperature, pain and touch sensation on the right extremities. Plain X-ray film and CT scan showed a broken needle in the interspinous ligament between C1/C2 vertebrae, the tip of the needle appearing to be in the spinal canal. The needle was removed surgically nineteen days after the accident. Intraoperative fluoroscopic monitoring with injection of dye enabled the needle to be found without difficulty. Postoperative course was uneventful, and her pain and sensory impairment gradually disappeared. Once the diagnosis for cervical spinal cord injury by an acupuncture needle is made, the needle should be removed surgically as soon as possible, especially prior to the development of motor symptoms. This is because movement of the needle in the spinal cord is considered to be a main possible cause of the development and progression of symptoms.

Acupuncture Analgesia↗
PubMed1991

Molecular cloning of human XPAC gene homologs from chicken, Xenopus laevis and Drosophila melanogaster.

We cloned homologs of the human Xeroderma Pigmentosum Group A complementing (XPAC) gene from chicken, Xenopus laevis and Drosophila melanogaster. A comparison of the amino acid sequences of these homologs with that of the human XPAC protein revealed that in the NH2-terminal domain there are only two conserved regions, one of which is presumed to function as the nuclear localization signal, whereas the COOH-terminal domain is highly conserved, the frequency of identical amino acids in all four XPAC proteins being 50%, and the four cysteine residues predicted to form a zinc-finger motif, and three other cysteine residues are all conserved. These results strongly suggest that the COOH-terminal domain containing a zinc-finger motif plays an important role in the function of these proteins.

Amino Acid Sequence↗
PubMed1991

Altered response to growth factors or retinoic acid in phenotypic transformation of normal rat kidney cells expressing human c-fos gene.

Anchorage-independent growth of normal rat kidney (NRK) fibroblast in soft agar depends on both transforming growth factor beta (TGF beta) and epidermal growth factor (EGF). To examine whether c-fos protein is involved in phenotypic transformation of NRK cells, we have transfected and isolated several NRK cell lines that carry the human c-fos gene fused to the metallothionein IIA promoter. A transfectant, Nf-1, had constitutive levels of the human c-fos expression. Anchorage-independent growth of Nf-1 was already stimulated by EGF alone, and the colony sizes of Nf-1 were comparable to those of the parental NRK in the presence of both EGF and TGF beta. Anchorage-independent growth of NRK could be observed in the presence of TGF beta or retinoic acid or platelet derived growth factor (PDGF) and EGF. No growth of NRK in soft agar appeared when basic fibroblast growth factor (bFGF) and EGF were present. By contrast, anchorage-independent growth of Nf-1 was surprisingly enhanced by EGF and TGF beta or retinoic acid or PDGF or bFGF. Expression of the human c-fos gene may compensate the signal to phenotypic transformation induced by TGF beta as well as retinoic acid or PDGF or bFGF.

Animals↗
PubMed1991

Rapid turnover of low density lipoprotein receptor in human monocytic THP-1 cells.

We examined whether human monocyte-derived macrophages had low density lipoprotein (LDL) receptors with a short life span. The human monocytic leukemia cell line, THP-1, was highly differentiated when treated with phorbol ester. LDL receptors degraded rapidly with half-lives of 3-4 h in THP-1 cells before phorbol ester treatment. During the transition into monocytic cells, expression of the LDL receptor gene was not affected. However, relative degradation rates of LDL receptors normalized by those of cellular total proteins were about twice as fast in phorbol ester-treated THP-1 cells compared to untreated cells.

Cell Differentiation↗
PubMed1991

Endogenous basic fibroblast growth factor-dependent induction of collagenase and interleukin-6 in tumor necrosis factor-treated human microvascular endothelial cells.

Tumor necrosis factor-alpha (TNF-alpha) has been shown to enhance the synthesis of interleukin-6 (IL-6) and collagenase in human omental microvascular endothelial (HOME) cell (Mawatari, M., Kohno, K., Mizoguchi, H., Matsuda, T., Asoh, K., Van Damme, J. V., Welgus, H. G., and Kuwano, M. (1989) J. Immunol. 143, 1619-1627). In the present study, we have examined whether the TNF-alpha-induced synthesis of IL-6 or collagenase in HOME cells is mediated by an inducible growth factor. Among several growth factors examined, we found that the expression of basic fibroblast growth factor (bFGF) mRNA was the one most prominently enhanced when HOME cells were treated with TNF-alpha. The increase of bFGF mRNA by TNF-alpha in HOME cells was observed in both a dose- and time-dependent manner when assayed by Northern blot analysis. The induction of bFGF mRNA was observed by 3 h after incubation with TNF-alpha, and the maximal increase of 5-fold was obtained after 12 h of incubation with 100 units/ml TNF-alpha. Western blot analysis confirmed the enhanced synthesis of bFGF by TNF-alpha. Metabolic labeling and immunoprecipitation assays of bFGF showed that exposure to TNF-alpha enhanced secretion of bFGF into culture medium and also that TNF-alpha stimulated the production of bFGF molecules with molecular masses of 18, 21, and 22.5 kDa in HOME cells. TNF-alpha induced the expression of collagenase mRNA and IL-6 mRNA in HOME cells as well, and the coadministration of neutralizing anti-bFGF antibody almost completely blocked the effects of TNF-alpha. The treatment of HOME cells with exogenous bFGF significantly stimulated the expression of collagenase mRNA and IL-6 mRNA in HOME cells. Therefore, the biological effects of TNF-alpha on HOME cells may be mediated, at least in part, by TNF-alpha-induced bFGF.

Blotting, Northern↗
PubMed1991

Increased phosphorylation of DNA topoisomerase II in etoposide-resistant mutants of human cancer KB cells.

We have isolated two etoposide (VP16)-resistant cell lines, KB/VP-1 and KB/VP-2, from human cancer KB cells after stepwise exposure to increasing doses of VP16. KB/VP-1 and KB/VP-2 showed 30- and 50-fold higher resistance to VP16 and also 20- and 30-fold higher resistance to teniposide than the parent cell line. Furthermore, both resistant cell lines showed more than 2-fold cross-resistance to Adriamycin and daunomycin than KB cells. The levels of accumulation and outward transport of radioactive VP16 were similar in KB/VP-1, KB/VP-2, and KB. The activity of nuclear extracts of DNA topoisomerase II for both KB/VP-1 and KB/VP-2 assayed by decatenation of kinetoplast DNA was consistently similar to that of KB. However, in both immunoblot assay with specific anti-topoisomerase II antibody and Northern blot analysis with specific human DNA topoisomerase II complementary DNA, cellular levels of topoisomerase II in both resistant cell lines were less than one-tenth the level in KB. The cellular levels of DNA topoisomerase I, however, were similar between the mutants and their parent. A quantitative precipitation assay of covalent DNA-topoisomerase II complexes showed greatly reduced VP16-induced cleavages of 3'-32P-DNA by nuclear extracts of KB/VP-1 or KB/VP-2 cells in comparison with KB cells. The relative specific phosphorylation of DNA topoisomerase II was about 14- to 18-fold higher in the mutants than in the parental cells. Phosphoamino acid analysis of DNA topoisomerase II showed that serine was the phosphorylated amino acid in all three cell lines, KB, KB/VP-1, and KB/VP-2. These data suggest that reduced expression of DNA-topoisomerase II might account for the acquired VP16 resistance and reduced VP16-induced cleavages of DNA-topoisomerase II complexes in both VP16-resistant variants.

Carcinoma, Squamous Cell↗
PubMed1991

Construction and characterization of an Escherichia coli mutant with a deletion of the metZ gene encoding tRNA (f1Met).

The Escherichia coli metZ gene encoding tRNA (f1Met) was replaced by the chloramphenicol-resistance-encoding gene. The resulting mutant exhibited slightly lower growth rates as compared to the wild type at 37 degrees C or 42 degrees C, but grew apparently slower than the latter at 30 degrees C, indicating a slight cold sensitivity of growth. beta-Galactosidase was produced efficiently from the start codon AUG of the intact lacZ gene or trpA'::lac' Z fusion gene, in the metZ deletion mutant. The lac repressor from the lacI gene and the chimeric protein from a hupB' ::lac'Z fusion gene, whose start codons are GUG, were also synthesised in the deletion mutant. These results provide evidence that tRNA (f1Met) is not essential for growth of E. coli and that the start codons, AUG and GUG, are both recognized by tRNA (f1Met), a minor N-formyl methionine-specific tRNA, in the tRNA (f1Met)-depleted cells.

Blotting, Southern↗
PubMed1991

Counteraction of estradiol-induced activation of tissue-type plasminogen activator in a human breast cancer cell line by an anti-estrogen, LY117018.

LY117018 is a non-steroid anti-estrogen which exhibits about 100 times higher affinity for estrogen receptor than tamoxifen, another anti-estrogen. The cell line ES-1, which was isolated from human breast cancer MCF-7 cells, was highly sensitive to the cytocidal action of estradiol. Growth of ES-1 cells was inhibited by 10(-8)M 17 beta-estradiol, a concentration that stimulated the growth of parental MCF-7 cells. The estradiol-induced growth inhibition of ES-1 cells was almost completely reversed by treatment with LY117018, but not by treatment with tamoxifen. The relative binding affinity of LY117018 for estradiol receptor was equal to that of estradiol in both MCF-7 and ES-1 cells. Treatment of ES-1 cells with estradiol specifically induced tissue-type plasminogen activator (t-PA), whereas such estradiol-induced activation was not observed in parental MCF-7 cells. Quantitative immunoreactive assays and Northern blot analysis showed that estradiol-induced expression of t-PA was blocked by LY117018 in ES-1 cells. The inhibitory effect of tamoxifen was about 100 times lower than that of LY117018. The inhibition of t-PA gene expression by LY117018 might be due to competitive inhibition with estradiol in estradiol receptor binding.

Breast Neoplasms↗
PubMed1991

Microtubule bundles in fish cerebellar Purkinje cells.

The initial axon segments and the cell bodies of Purkinje cells were examined in electron microscopic serial sections and toluidine blue semithin sections of goldfish cerebellum. We observed two characteristic cytoplasmic features different from those of other vertebrate neurons, 1. The areas of Nissl substance and Golgi apparatus are sharply divided in the periphery and center of the cytoplasm, 2. Microtubules fasciculated by cross-bridges in the axon hillock and initial axon segment remain bundled in the perikaryon, pass near the eccentric nucleus, and enter into the Golgi area of the central cytoplasm, where they are surrounded by mitochondria. We suggest that the intracellular fasciculated microtubules may establish a prepared pathway for fast anterograde and retrograde transport to and from the Golgi area of the cell body.

Animals↗
PubMed1991

Descending input from the hypothalamic paraventricular nucleus to sympathetic preganglionic neurons in the rat.

The descending projection of the hypothalamic paraventricular nucleus (PVN) to the sympathetic preganglionic neurons (SPNs) in the upper thoracic cord of the rat was studied. PVN-fibers were labeled by anterograde transport of Phaseolus vulgaris leucoagglutinin (PHA-L), while SPNs were retrogradely labeled with cholera toxin subunit B (CTb) which was injected into the superior cervical ganglion. SPNs labeled with CTb were mainly observed in the nucleus intermediolateralis (IML) pars principalis and pars funicularis, and a small number of them were in the nucleus intercalatus (IC) and central autonomic nucleus (CA). SPNs found in the IML had dendrites that projected in various directions. Five types of dendritic projections were noted: medial, rostral, caudal, lateral (including dorsolateral) and ventral. Longitudinal dendritic bundles interconnected each cell cluster in the IML. Medial dendrites of the IML, together with dendrites of the IC and CA, formed transverse dendritic bundles extending from the IML to the central canal. The transverse dendritic bundles disentangled near the midline and formed a loose dendritic plexus in the region just dorsal to the central canal. PVN-fibers labeled with PHA-L were observed primarily in lamina I and intermediate gray (lamina VII). Although varicose PVN-fibers and SPNs coexisted in the IML, the tight packing of the dendritic bundles prevented any clear demonstration of direct contacts between them. On the other hand, PVN-fibers were occasionally found to appose and wind around the primary or secondary dendrites of some SPNs of the CA and IC. These dendrites were studied with varicosities of PVN-fibers for a short length, and terminal boutons of PVN-fibers were also seen to make contact directly with the dendrities. The results of this study substantiated a direct connection between the PVN and SPNs, using a combination of immunohistochemical techniques for PHA-L and CTb. The possible involvement of a direct pathway from the PVN to SPNs in cardiovascular regulation is discussed.

Animals↗
PubMed1991

Coincidence of "ladder-like patterns" in distributions of monoaminergic terminals and sympathetic preganglionic neurons in the rat spinal cord.

A ladder-like pattern of distribution of sympathetic preganglionic neurons (SPNs) was compared with that of monoaminergic terminals in the upper thoracic spinal cord of the rat. SPNs were identified by a retrograde labeling with cholera toxin subunit B (CTb) injected into the superior cervical ganglia of both sides. Monoaminergic terminals were stained immunohistochemically by using antisera raised against 5-hydroxy-tryptamine (5-HT) or dopamine-beta-hydroxylase (DBH). SPNs showing full dendritic arbors were found in all of the sympathetic preganglionic nuclei. They formed a ladder in the horizontal plane. The nucleus intermediolateralis was connected with the central autonomic nucleus by many transverse dendritic bundles. Photomontages of serial sections of material stained alternatively with antisera against CTb and 5-HT or DBH clearly showed a close correlation between SPNs and monoaminergic terminals. There is no transverse dendritic bundle of SPNs without the accompaniment of monoaminergic terminals.

Animals↗
PubMed1991

Intracellular calcium levels in canine basilar artery smooth muscle following experimental subarachnoid hemorrhage: an electron microscopic cytochemical study.

Changes in intracellular calcium levels in canine basilar arterial smooth muscle were semiquantitatively measured by an electron microscopic cytochemical technique using a combined oxalate-pyroantimonate method. Measurements made after subarachnoid hemorrhage were compared with those made after contraction induced by prostaglandin F2 alpha. Fifteen minutes after topical application of the drug, when the basilar artery was constricted by 20%, 15% of smooth muscle cells contained a large amount of intracellular calcium. One hour later, the diameter of the basilar artery and intracellular calcium precipitation returned almost to control levels. Fifteen minutes after the first intracisternal injection of autologous blood, when acute vasospasm was angiographically evident, 13% of smooth muscle cells contained a large amount of calcium. After 1 h, when acute vasospasm had already abated, the number of smooth muscle cells containing a large amount of calcium markedly increased to 37% and some smooth muscle cells showed early degenerative findings such as intracytoplasmic vacuoles including calcium accumulation. After 48 h, when delayed vasospasm had already started, the calcium deposits and early degenerative changes had decreased significantly. After 49 h and 4 days (1 h and 48 h after the second injection of blood), the change in the amount of calcium was the same as at 1 h and 48 h after the first injection, respectively, but degeneration of smooth muscle cells increased. Therefore, acute vasospasm after subarachnoid hemorrhage may be caused by an initial elevation of intracellular calcium levels, as is the case with drug-induced contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Variations in radioimmunoscintigraphic detection of tumor showed by five monoclonal antibodies to carcinoembryonic antigen.

Radioimmunoscintigraphy using mouse monoclonal antibodies to various parts of a carcinoembryonic antigen (CEA) molecule was performed. Four radiolabeled antibodies (F4-82, 28A, F3-30, F33-104) were injected into tumor transplanted nude mice to compare the accumulation of these antibodies in tumors. The four antibodies were accumulated selectively in CEA- producing tumors. The tumor visualization correlated with the tumor/blood radioactivity ratio, whereas the tumor/blood radioactivity ratio did not correlate with the in vitro percent binding to tumor cells or the in vivo percent injected dose in CEA-producing tumors. Among the four antibodies, F33-104 showed the highest tumor/blood radioactivity ratio and the best image quality in any CEA-producing tumor. These results suggest that the antibody which has a high tumor/blood ratio rather than high total tumor uptake may be useful for radioimmunoscintigraphy.

Animals↗
PubMed1991

Tumor necrosis factor and epidermal growth factor modulate migration of human microvascular endothelial cells and production of tissue-type plasminogen activator and its inhibitor.

Epidermal growth factor (EGF) induces tubular formation of cultured human microvascular endothelial (HME) cells in the gel matrix containing collagen, and tumor necrosis factor (TNF) disrupts the tubular formation (Mawatari et al. (1989) J. Immunol. 143, 1619-1627). Here we studied the effects of EGF and TNF on endothelial cell migration and on the production of proteases. Confluent HME cells, when wounded with a razor blade, moved into the denuded space. This migration was stimulated by EGF and inhibited by TNF in this assay and in the Boyden chamber assay. Antibody against tissue-type plasminogen activator (t-PA) inhibited the EGF-stimulated cell migration in both assays by approximately 70%, but antibody against urokinase-type plasminogen activator (u-PA) could not inhibit its migration. Quantitative immunoreactive assays showed an approximately three- to fourfold increase of t-PA at 6 to 12 h after EGF addition, and TNF inhibited the production of t-PA by 50%. Northern blot analysis showed increased expression of t-PA mRNA by EGF alone in a time- and dose-dependent manner, whereas TNF alone inhibited its expression in a time- and dose-dependent manner. Northern blot analysis showed a significant increase of plasminogen activator inhibitor-1 (PAI-1) mRNA when EGF or TNF was present. Stimulation by EGF of cell migration of HME cells and its inhibition by TNF appear to be closely correlated with the cellular modulation of t-PA and PAI-1 activities.

Cell Movement↗
PubMed1991

Immunohistochemical study of tyrosine-hydroxylase-positive cells and fibers in the chicken spinal cord.

Tyrosine hydroxylase (TH)-positive cells and fibers were examined by immunohistochemistry in the chick spinal cord. TH-positive cells, which were located in laminae I, V and X, were most frequently found in the rostral part of the cervical spinal cord, with fewer cells being found in more caudal levels of the spinal cord. TH-positive cells located in lamina X, which were bipolar in shape, were mainly found in regions lateral as well as just ventral to the central canal. They had processes reaching to the central canal. The terminals of these cerebrospinal-fluid-contacting cells were oval in shape, and were most frequently found at the ventral wall of the central canal. There were dense clusters of TH-positive fibers in lamina X. A meshwork-like structure of TH-positive fibers was found over the lateral wall of the central canal. A high density of TH-positive fibers was also found in the medial part of laminae V-VII. In lamina IX, small numbers of TH-positive fibers were observed in the lateral motor column of the brachial spinal cord, and in the medial and lateral motor columns of the lumbosacral spinal cord. However, within the medial motor column of the brachial spinal cord TH-positive fibers were densely distributed around somal as well as dendritic profiles. Similar to our previous observations on serotoninergic fibers. TH-positive fibers were also differentially distributed in the ventral horn of the chicken spinal cord: a high density of TH-positive fibers was localized to specific regions of the spinal motor nucleus.

Animals↗