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Biomedical subjects

Y Nakase

Publications and source records attributed to Y Nakase.

At least 19 recordsLinked to original sources
PubMed1992

Bordetella heat-labile toxin causes release of radioactivity from smooth muscle cells labeled with [14C]arachidonic acid.

The effect of Bordetella heat-labile toxin (HLT) on cultured vascular or tracheal smooth cells labeled with [14C]arachidonic acid for 3 h was examined. At 37 degrees C, in the presence of Ca2+, HLT induced the release of radioactive substances from the cells in a dose-dependent manner but HLT had no effect on release of radioactivity from cells at 0 degrees C or in the absence of Ca2+. After cells were exposed to HLT, a 2-h lag period occurred before release of radioactivity was detected. The substances released from cells by HLT were identified as arachidonic acid and phosphatidylcholine.

Animals↗
PubMed1992

Heat-labile toxin from Bordetella parapertussis induces contraction of smooth muscle cells in culture.

The ability of Bordetella heat-labile toxin (HLT) to contract various types of cells in culture was examined. HLT from B. parapertussis induced contraction of cultured smooth muscle cells from trachea, intestine, uterus and vas deferens as well as from aorta. The time required for contraction decreased as the dose of B. parapertussis HLT increased from 3 to 100 MID/ml. Upon exposure of cells to concentrations of toxin greater than 100 MID/ml, at least 2 hr was required for contraction. HLT from B. parapertussis did not affect cultured cardiac or skeletal muscle cells within 8 hr after the exposure to HLT (100 MID/ml). No effect on other types of primary culture cells or established cells such as Chinese hamster ovary (CHO) cells has been described. These data indicate that the primary target cells for HLT might be smooth muscle cells.

Animals↗
PubMed1992

Cytotoxic effects of antitumor agents on mouse tracheal organ cultures at ultrastructural level.

A cytotoxic effect of antitumor agents (mitomycin C;MMC, adriamycin;ADM, bleomycin;BLM, 5-fluorouracil;5-FU, and cisplatin;CDDP) on ciliated epithelial cells of mouse tracheal organ cultures was studied in transmission electron microscopy. Mouse tracheal rings incubated with each agent in a concentration of 1 microgram/ml or 10 micrograms/ml were observed after 1, 2, and 20 hr of the incubation. After 2 hr, the ciliated epithelial with MMC or ADM of 1 microgram/ml exhibited appearance of lipid droplets in the nonciliated cells and the swelling of mitochondria and epithelial cells. Further incubation of 20 hr with those agents resulted in the pronounced degeneration including the ciliary subsidence into intracellular spaces, balloon-like ciliary swelling, and cellular destruction. Whereas, the ciliated epithelia with 5-Fu, BLM or CDDP did not show any notable change within 2 hr. After 20 hr, these exhibited the swelling of mitochondria, cilia and epithelial cells. The ciliated epithelia incubated with MMC or ADM of a greater concentration of 10 micrograms/ml showed remarkable cytotoxic effects after 1 hr of the incubation. The morphological changes in the epithelial cells with 1 hr incubation were almost similar to those of 20 hr incubation with the 1 microgram/ml. After 20 hr, the cellular degeneration proceeded to extremely flattened epithelial cells with disappearance of cilia and appearance of numerous vacuoles. Those with 5-FU, BLM or CDDP of 10 micrograms/ml exhibited ciliary swelling after 2 hr, but the morphological changes of 5-FU were more remarkable than those of BLM or CDDP. After 20 hr, the pronounced degeneration was observed, and it was similar to one of MMC or ADM of 2 hr incubation.

Animals↗
PubMed1991

Role of rectus muscle enlargement in clinical profile of dysthyroid ophthalmopathy.

Using logistic regression analysis, a correlation between enlargement patterns of the 4 rectus muscles and the occurrence of a variety of dysthyroid ophthalmopathy-associated ocular symptoms were analyzed in 698 eyes of 349 patients with this disorder. The condition of each rectus muscle was evaluated by computed tomography, and the various ocular symptoms were classified according to the Inoue classification system. The enlargement pattern, particularly when involving the inferior and medial recti, was found to have a strong statistical correlation with the occurrence of individual ocular symptoms. Additionally, the probabilities of the occurrence of most of the ocular symptoms were generally greater in those eyes with 2-, 3- or 4-muscle enlargement patterns than in those eyes with one or no enlarged rectus muscle.

Adult↗
PubMed1990

Development of a cell culture assay for Bordetella parapertussis heat-labile toxin.

A cell culture assay for heat-labile toxin isolated from Bordetella parapertussis has been developed. In this assay, the ability of heat-labile toxin to induce contraction of vascular smooth muscle cells is measured. The method allows for detection of as little as 0.6 ng/ml of the toxin. The results obtained from this in vitro assay correlated well with those obtained with in vivo assays indicating that the cell culture assay may be a useful alternative to animal assays.

Animals↗
PubMed1990

Inhibition of heat-labile toxin from Bordetella parapertussis by fatty acids.

The ability of heat-labile toxin (HLT) from Bordetella parapertussis to induce skin lesions in guinea pigs was found to be inhibited by lipids isolated from skin layers of adult mice, which are refractory to the lesion-inducing activity of HLT. These lipids were identified as linoleic and oleic acids. Other long-chain unsaturated fatty acids were also found to inhibit HLT; however, fatty alcohols, neutral lipids, phospholipids, cholesterol, prostaglandin, and leukotriene had no measurable effects on HLT action. The data presented in this report indicate that the ability of HLT to induce skin lesions in animals may depend, at least in part, on the free fatty acid content of the skin layer.

Animals↗
PubMed1990

Effects of exogenous agents on the action of Bordetella parapertussis heat-labile toxin on guinea pig skin.

Injection of sonic extracts of Bordetella parapertussis into the shaved backs of guinea pigs produced hemorrhagic necrosis, which previously has been attributed to the action of heat-labile toxin. As heat-labile toxin was purified from this crude mixture, its ability to induce hemorrhagic lesions decreased significantly. However, ischemic lesions were apparent after injection of the purified toxin. These lesions, while not hemorrhagic in nature, were marked by erythema surrounded by a region in which the ischemia was apparent. Exogenous agents were found to alter the nature of the skin lesion induced by heat-labile toxin. The lipid A portion of endotoxin in combination with heat-labile toxin caused hemorrhagic lesions surrounded by a ring of ischemia, whereas bovine serum albumin increased the area of erythema. While the nature of lesions induced by heat-labile toxin was affected by exogenous agents, the diameter of ischemia produced by the toxin was found to be independent of the presence of these agents and was linear with toxin dose. These results indicate that induction of hemorrhagic necrosis may not be a reliable indicator of heat-labile toxin activity. Instead, measurement of the ischemic lesion produced by heat-labile toxin may be a useful assay for the toxin.

Animals↗
PubMed1989

Pyridine nucleotide fluorometry in preserved porcine liver with fluorocarbon emulsion.

Oxidation-reduction changes in pyridine nucleotide fluorescence were investigated in perfused and preserved porcine liver. A fluorocarbon emulsion (FC-43) was administered to the perfusate as an oxygen carrier to obtain full oxidation level by portal perfusion at a physiological low flow rate. A satisfactory reading was obtained by portal perfusion with EuroCollins' solution containing 10% v/v FC-43 at a rate of 0.5 ml/min/g liver. The amplitude (R x A) and the changing velocity (R x V) from full oxidation to full reduction were determined in the resultant trace curve. Both R x A and R x V decreased in inverse proportion to the duration of preservation period (3, 6, 12 hr). Adenine nucleotide content, hepatic energy charge level, and ketone body ratio in the tissue were simultaneously measured, and they also decreased proportionally to the duration of preservation. There were close positive correlations between R x A and total adenine nucleotide concentration (r = 0.841, P less than 0.01), between R x V and energy charge (r = 0.787, P less than 0.01), and between R x V and tissue ketone body ratio (r = 0.881, P less than 0.01). These results suggest that pyridine nucleotide fluorometry can accurately follow the cellular function of isolated porcine liver by administration of FC-43 in perfusate. This fluorometry may also have potential application in evaluating viability of a large organ like the human liver graft.

Adenine Nucleotides↗
PubMed1989

Electron microscopic observations on ciliated epithelium of tracheal organ cultures infected with Bordetella bronchiseptica.

Using mouse tracheal organ cultures, the pathogenic effect of Bordetella bronchiseptica to epithelial cells was studied by electron microscopy. The ultrastructure of epithelial cells in uninfected tracheal rings was preserved well for longer than 3 days. In mouse tracheal rings infected with graded doses (3 x 10(5) to 10(7) CFU/ml) of phase I B. bronchiseptica, the colonization in the interciliary spaces of ciliated epithelial cells was observed after a 20-hr infection period. The infected tracheal rings showed swelling of nonciliated cells as well as ciliated cells, rupture of cell membrane of cilia, swelling and disappearance of cilia, and atrophic cytomorphosis of epithelial cells. The severity of these changes occurred depending on the infection doses. These changes were essentially similar to those observed previously in the tracheal epithelia of the B. bronchiseptica-infected mice. The usefulness of this in vitro model was suggested for studying the pathogenesis of Bordetella infection.

Animals↗
PubMed1988

Cytopathic effect of heat-labile toxin of Bordetella parapertussis on aortic smooth muscle cells from pigs or guinea pigs.

The in vitro effect of the heat-labile toxin (HLT) of Bordetella parapertussis on HeLa, baby hamster kidney (BHK), chinese hamster ovary (CHO), myeloma (Pa-NS-1), human embryonic lung (HEL-R66) cells, erythrocytes, adipocytes and lymphocytes from guinea pigs, mice or rats, or aortic smooth muscle cells from pigs or guinea pigs was examined. Within 8, 6, 4, 2, and 2 hr after the exposure to 1, 3, 10, 30, and 100 MNDs/ml of HLT, respectively, the cultured smooth muscle cells only showed a cytopathic change. When the cells exposed to HLT were washed out within 60 min post-exposure, the change could be induced with an extend period of lag. Histamine, KCl or norepinephrine caused similar change in the cells, but the period of lag was within 30 min. The HLT activity was neutralized by an anti-B. parapertussis- or B. bronchiseptica-HLT guinea pig IgG. HLT had no effects on any other cells tested.

Animals↗
PubMed1988

Electron microscopic observations on tracheal epithelia of mice infected with Bordetella bronchiseptica.

To clarify the pathogenesis of Bordetella in vivo infection, the tracheal epithelia of mice were examined in detail by electron microscopy at various intervals after intranasal inoculation with graded doses of phase I Bordetella bronchiseptica. In mice infected with a lethal dose (6 to 7 x 10(7) CFU), a remarkable rupture of the cell membranes of cilia and microvilli of the middle trachea was found on day I postinfection. The rupture of the membrane was observed over the entire tracheal epithelia, on day 2 after infection. The affected cilia were constricted at the transitional region and were broken off. In the ciliated cells the adherence of organisms to ciliary apexes and colonization in the interciliary spaces were also remarkable. In both the ciliated and nonciliated epithelial cells, the cytoplasmic vacuolation and pyknosis or karyorrehexis were also notable. In mice infected with one-tenth of the lethal dose, similar findings were seen, but appeared more slowly and the bacteria were not seen attaching to ciliary apexes. In mice receiving one-hundredth of the lethal dose, only mild cilial abnormality such as aggregation of cilia, and slight cytoplasmic vacuolation were found 6 days postinfection. Based on these findings, a possible mechanism of the ciliary damages produced by B. bronchiseptica was postulated.

Animals↗
PubMed1988

Contractile action of heat-labile toxin of Bordetella parapertussis on aortic smooth muscles of pigs.

Using both vascular smooth muscle strips (VSMS) and cultured cells (VSMC) from aortas of pigs, the contractile action of Bordetella heat-labile toxin (HLT) purified from B. parapertussis was studied in an attempt to elucidate the mechanisms of its action. HLT induced contractions in VSMC in parallel with the increase of Ca2+-influx. The HLT-induced Ca2+-influx and contraction were not influenced by verapamil or diltiazem, though a certain extension of the lag period was seen. The contractile action of HLT on VSMS and VSMC was not influenced either by diltiazem or quinacrine; that on VSMC was not influenced by prednisolone, indomethacin, aspirin, CV-3988, FPL-55712, ruthenium red, or TEAC. On VSMS, prednisolone caused the extension of lag period following HLT exposure. The action of HLT on VSMS was inhibited by TMB-8, whereas that on VSMC was not though the extension of lag period was seen. The HLT-induced contraction in both VSMS and VSMC was completely inhibited by H-7. The contraction in VSMS, but not in VSMC, was inhibited by H-8. HLT did not induce specific activation of the protein kinases in VSMC. The addition of cGMP or cAMP brought about relaxation in the HLT-exposed VSMS contracting in maximum. HLT caused a significant increase in permeability of VSMC membrane to trypan blue, accompanied with contraction. Both HLT-induced contraction and increase in permeability were inhibited by dextran of M.W. 8,000, but not of M.W. 5,000. These results suggested that HLT acted on vascular smooth muscle cells by damaging the membrane permeability, but not by disturbing the known cascades or systems for physiological contractions, resulting in the increase in Ca2+-influx and then contractions.

Animals↗
PubMed1988

Mechanism of action of Bordetella heat-labile toxin on vascular smooth muscle strips and cells.

The mechanism of action of Bordetella heat-labile toxin (HLT) was analyzed in vitro using vascular smooth muscle strips (VSMS) and cultured cells (VSMC), from aortas of pig, guinea pig, rabbit, rat or mouse. HLT induced contractions to both VSMS and VSMC, but not other types of tissues and cells. HLT induced the increase of Ca2(+)-influx in parallel with the contraction. These HLT activities were not influenced by the addition of verapamil, diltiazem, or TMB-8, though a certain extension of the lag period was seen. The contractile action on VSMC was not influenced by a various blockers of cascades or systems. The HLT-induced contraction in VSMC was completely inhibited by H-7, but not by H-8. HLT did not induce specific activation of the protein kinases in VSMC. HLT induced the permeability changes in VSMS or VSMC membranes to cyclic nucleotides or trypan blue. Both HLT-induced contraction and permeability change were inhibited by dextran of M.W. 8,000. 125I-HLT bound immediately to VSMC depending on the HLT dose. At 37 degrees C, the binding ratio in maximum was approximately 0.8% of total HLT added at 60 min after exposure. At 4 degrees C, it was less than 20% of that at 37 degrees C. The labeled HLT binding to VSMC was released readily by washing. From these results, possible mechanism of HLT action was discussed.

Animals↗
PubMed1988

Evaluation of cytoprotective drugs for liver preservation by pyridine nucleotide fluorometry.

The cytoprotective effects of membrane-stabilizing drugs, such as chlorpromazine, allopurinol, dibucaine, phenoxybenzamine, and OP41483 (prostacyclin analogue), administered to perfusate and preservation medium were studied in rat liver, after 24 hours' preservation, by assessment of pyridine nucleotide fluorescence. On the fluorometric trace curve, amplitude (RxA) and velocity (RxV) from oxidation to reduction were determined. Percent decrease of RxA (%RxA) and that of RxV (%RxV) after 24 hours' preservation were calculated. At the end of preservation, the concentration of total adenine nucleotides of the liver, hepatic adenylate energy charge, and prepared mitochondrial oxidative phosphorylative activity were also measured. In the groups given phenoxybenzamine, dibucaine, and allopurinol, there was no significant difference among these parameters. In the chlorpromazine group, energy charge and %RxV were higher than in the drug-free group (p less than 0.05). In the OP41483 group, both energy charge and phosphorylation rate were significantly higher (p less than 0.05) and %RxV was significantly high (p less than 0.01) at concentrations of more than 3 nmol/L, compared with the values for those without drugs. These results suggest that the Redoximeter can provide accurate information on the effectiveness of cytoprotective drugs. It is also suggested that OP41483 has potential application for maintaining graft viability for human liver transplantation.

Allopurinol↗
PubMed1987

Fluorometric study for the noninvasive determination of cellular viability in perfused rat liver.

Pyridine nucleotide fluorescence in perfused rat liver for the noninvasive determination of donor graft viability was investigated in relation to other metabolic indices, such as NAD concentration, adenine nucleotides, and mitochondrial phosphorylative activity. The amplitude between oxidation and reduction levels (RxA) in fluorometric trace, and the slope or the velocity of the trace curve from oxidation to reduction (RxV) were determined by the measurement of fluorescence from NAD(P)H, using a new fluorometric device, RxA and RxV decreased proportionally to the duration of preservation period (6, 12, 24, 48 hr) in simple cold storage. Other values of hepatic cell viability, such as total adenine nucleotides, energy charge, and mitochondrial phosphorylation rate, were simultaneously measured and also decreased proportionally to the duration of preservation period. There were close positive correlations between the percentage of RxA and NAD concentration (r = 0.724, p less than 0.01), between the percentage of RxA and total adenine nucleotides (r = 0.887, p less than 0.01), between the percentage of RxV and energy charge (r = 0.715, p less than 0.01), and between the percentage of RxV and phosphorylation rate/cytochrome a(+a3) (r = 0.837, p less than 0.01). These results suggest that this fluorometric method can provide an accurate noninvasive evaluation of donor graft viability--and, unlike the present indices of energy metabolism, it may be applied to evaluate the primary nonfunctioning graft prior to transplantation.

Adenine Nucleotides↗