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428 results on '"Nakatsu K"'

5. Thiazolidine Deprotection by 2-Aminobenzamide-Based Aldehyde Scavenger for One-Pot Multiple Peptide Ligation

Author

Nakatsu K, Akimitsu Okamoto, Hayashi G, and Murakami H

Subjects
chemistry.chemical_classification, chemistry.chemical_compound, chemistry, Yield (chemistry), Thiazolidine, Formaldehyde, Peptide, Native chemical ligation, Ligation, Combinatorial chemistry, Aldehyde, Scavenger (chemistry)
Abstract

Strategies for one-pot peptide ligation enable chemists to access synthetic proteins at a high yield in a short time. Herein, we report a new one-pot multi-segments ligation strategy using N-terminal thiazolidine (Thz) peptide and a formaldehyde scavenger. Among our designed 2-aminobenzamide-based aldehyde scavengers, 2-amino-5-methoxy-N’,N’-dimethylbenzohydrazide showed a good ability to capture formaldehyde from Thz at pH 4.0. This scavenger had compatibility with the conditions of native chemical ligation at pH 7.5. Using this scavenger for a model peptide ligation system, we performed one-pot four-segment ligation at a high yield without significant side reactions.

Published
2021
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9. Effect of glucose and oxygen deprivation on heme oxygenase expression in human chorionic villi explants and immortalized trophoblast cells

Author

Appleton, S.D., Lash, G.E., Marks, G.S., Nakatsu, K., Brien, J.F., Smith, G.N., and Graham, C.H.

Subjects
Preeclampsia -- Care and treatment, Preeclampsia -- Research, Biological sciences
Abstract

Although hypoxia induces heme oxygenase (HO)-1 mRNA and protein expression in many cell types, recent studies in our laboratory using human placental tissue have shown that a preexposure to hypoxia does not affect subsequent HO enzymatic activity for optimized assay conditions (20% [O.sub.2]; 0.5 mM NADPH; 25 [micro]M methemalbumin) or HO-1 protein content. One of the consequences of impaired blood flow is glucose deprivation, which has been shown to be an inducer of HO-1 expression in HepG2 hepatoma cells. The objective of the present study was to test the effects of a 24-h preexposure to glucose-deprived medium, in 0.5 or 20% [O.sub.2], on HO protein content and enzymatic activity in isolated chorionic villi and immortalized HTR-8/SVneo first-trimester trophoblast cells. HO protein content was determined by Western blot analysis, and microsomal HO enzymatic activity was measured by assessment of the rate of CO formation. HO enzymatic activity was increased (P < 0.05) in both placental models after 24-h preexposure to glucose-deficient medium in 0.5 or 20% [O.sub.2]. Preexposure (24 h) in a combination of low [O.sub.2] and low glucose concentrations decreased the protein content of the HO-1 isoform by 59.6% (P < 0.05), whereas preexposure (24 h) to low glucose concentration alone increased HO-2 content by 28.2% in chorionic villi explants (P < 0.05). In this preparation, HO enzymatic activity correlated with HO-2 protein content (r = 0.825). However, there was no correlation between HO-2 protein content and HO enzymatic activity in HTR-8/SVneo trophoblast cells preexposed to 0.5% 02 and low glucose concentration for 24 h. These findings indicate that the regulation of HO expression in the human placenta is a complex process that depends, at least in part, on local glucose and oxygen concentrations. placenta; preeclampsia; carbon monoxide; hypoxia

Published
2003

10. Effects of hypoxia on heme oxygenase expression in human chorionic villi explants and immortalized trophoblast cells

Author

Appleton, S.D., Marks, G.S., Nakatsu, K., Brien, J.F., Smith, G.N., Graham, C.H., and Lash, G.E.

Subjects
Physiology -- Research, Hypoxia -- Physiological aspects, Biological sciences
Abstract

Although hypoxia induces heme oxygenase (HO)-1 protein and mRNA expression in many cell types, hypoxia has also been shown to decrease HO-1 mRNA and protein expression. We tested the hypothesis that 24-h preexposure to hypoxia in human placental preparations suppresses HO protein expression and enzymatic function. Immortalized HTR-8/SVneo first-trimester trophoblast cells and explants of normal human chorionic villi (CV) from term placentas were cultured for 24 h in 1%, 5%, or 20% [O.sub.2]. HO protein levels were determined by Western blot analysis, and microsomal HO activity was measured. HO-2 protein content was decreased by 17% and 5% in human trophoblast cells after 24-h exposure to 1% and 5% [O.sub.2], respectively, versus 20% [O.sub.2]. In contrast, HO-2 protein content in CV explants was unaffected by changes in oxygenation. HO-1 protein content, which was barely detectable in both biological systems, was not affected by changes in oxygenation. Similarly, HO enzymatic activity was unchanged in both preparations after 24-h exposure to 1%, 5%, or 20% [O.sub.2]. The above data do not support the hypothesis that hypoxia in the human placenta suppresses both HO protein content and HO protein function. The present observations reinforce the necessity to determine both HO protein expression and function. heme oxygenase activity; heme oxygenase-1 expression; carbon monoxide; hypoxia; placenta

Published
2003

11. Relationship between tissue damage and heme oxygenase expression in chorionic villi of term human placenta

Author

Lash, G.E., McLaughlin, B.E., Macdonald-Goodfellow, S.K., Smith, G.N., Brien, J.F., Marks, G.S., Nakatsu, K., and Graham, C.H.

Subjects
Chorion -- Physiological aspects, Tissues -- Physiological aspects, Oxidases -- Physiological aspects, Placenta -- Physiological aspects, Biological sciences
Abstract

Heme oxygenase (HO) catalyzes the oxidation of heme to carbon monoxide (CO), biliverdin, and iron and is thought to play a role in protecting tissues from oxidative damage. There are three isoforms of HO: HO-1 (inducible), HO-2 (constitutive), and HO-3 (unknown function). Preeclampsia is characterized by an inadequately perfused placenta and areas of tissue damage. We hypothesized that damaged areas of placentas from women with PE and uncomplicated pregnancies are associated with an alteration in HO expression. Compared with microsomes isolated from morphologically normal and peri-infarct chorionic villi of pathological placentas, microsomes from infarcted chorionic villi from the same placentas had decreased HO activity measured under optimized assay conditions. There was no correlation between microsomal HO levels and activity and tissue damage in uncomplicated pregnancies. Whereas there was no significant difference in HO-1 protein levels across all regions of uncomplicated and mildly preeclamptic pregnancies, HO-2 protein levels were decreased (P < 0.05) in peri-infarct regions and infarcted chorionic villi of mildly preeclamptic pregnancies. Immunohistochemical analysis revealed an apparent decrease in both HO-1 and HO-2 protein expression in damaged tissues. HO-1 and HO-2 were immunolocalized in the syncytiotrophoblast layer of the chorionic villi, the underlying cytotrophoblast, and in the vascular endothelium. This study suggests that the ability of the chorionic villi to oxidize heme to CO, biliverdin, and iron may be compromised in areas of tissue damage in the placenta of women with preeclampsia. carbon monoxide; preeclampsia; pregnancy

Published
2003

19. Abstracts

Author

Crosby, E. T., Halpern, S., Bill, K. M., Flynnn, R. J., Moore, J., Navaneelan, C., Cunningham, A., Yu, P. Y. H., Gamling, D. R., McMorland, G. H., Perreault, C., Guay, J., Gaudreault, P., Hollman, C., Meloche, R., Hackman, T., Sheps, S. B., Murray, W. B., Heiman, P. A., Slinger, P., Triolet, W., Jain, U., Rao, T. L. K., Dasari, M., Pifarre, R., Sullivan, H., Calandra, D., Friesen, R. M., Bjornson, J., Hatton, G., Parlow, J. L., Casey, W. F., Broadman, L. M., Rice, L. J., Dailey, M., Andrews, W. R., Stigi, S., Jendrek, V., Shevde, K., Withington, D. E., Saoud, A. Tazi, Ramsay, J. G., Bilodeau, J., Johnson, D., Mayers, I., Doran, R. J., Wong, P. Y., Mullen, Brendan J., Wigglesworth, D., Byrick, R. J., Kay, J. Colin, Stubbing, J. F., Sweeney, B. P., Dagher, E., Dumont, L., Lagace, G., Chartrand, C., Badner, N. H., Sandier, A. N., Leitch, L., Koren, G., Erian, R. F., Bunegin, L., Shulman, D. L., Burrows, F., O’Sullivan, K., Bouchier, D., Kashin, B. A., Wynands, J. E., Villeneuve, E., Blaise, G., Guerrard, M. J., Buluran, J., Effa, E., Vaghadia, H., Jenkins, L. C., Janisse, T., Scudamore, C. H., Patel, P. M., Mutch, W. A. C., Ruta, T. S., McNeill, B. R., Murkin, J. M., Gelb, A. W., Farrar, J. K., Johnson, G. D., Adams, M. A., Lillicrap, D. P., Lindblad, T., Beattie, W. S., Buckley, D. N., Forrest, J. B., Lessard, M. R., Trépanier, C. A., Baribault, J. P., Brochu, J. G., Brousseau, C. A., Cote, J. J., Denault, P., Whang, P., Moudgil, G. C., Daly, N., Morrison, D. H., Ogilvie, R., Man, J., Ehler, T., Leitch, L. F., Dupuis, J. Y., Martin, R., Tessonnier, J. M., Barry, A. W., Milne, B., Quintin, L., Gillon, J. Y., Pujol, J. F., DeMonte, F., Zhang, C., Hamilton, J. T., Zhou, Y., Plourde, G., Picton, T. W., Kellett, A., Pilato, M. A., Bissonnette, B., Lerman, J., Brown, K. A., Dundee, J. W., Sosis, M., Dillon, F., Stetson, J. B., Voorhees, W. D., Bourland, J. D., Geddes, L. A., Shoenlein, W. E., O’Leary, G., Teasdale, S., Knill, R. L., Rose, E. A., Berko, S. L., Smith, C. E., Sadler, J. M., Bevan, J. C., Donati, F., Bevan, D. R., Tellez, J., Turner, D., Kao, Y. J., Salidivia, V., Roldan, L., Orrego, H., Carmicheal, F. J., Kent, A. P., Parker, C. J. R., Hunter, J. M., Finley, G. A., Goresky, G. V., Klassen, K., McDiarmid, C., Shaffer, E., Vaughan, M., Randolph, J., Szalados, J. E., Lazzell, V. A., Creighton, R. E., Poon, A. O., Mclntyre, B., Douglas, M. J., Swenerton, J. E., Farquharson, D. F., Landry, D., Petit, F., Riegert, D., Koch, J. P., Maggisano, R., Devitt, J. H., Jense, H. G., Dubin, S. A., Silverstein, P. I., Rodriguez, N., Wakefield, M. L., Williams, R., Dubin, S., Smith, J. J., Hofmann, V. C., Jarvis, A. P., Forbes, R. B., Murray, D. J., Dillman, J. B., Dull, D. L., Cohen, M. M., Cameron, C. B., Johnston, R. G., Konopad, E., Jivraj, K., Hunt, D., Eastley, R., Strunin, L., Fairbrass, M. J., Laganiere, S., McGilvery, M., Foster, B., Young, P., Weisel, D., Parra, L., Suarez Isla, B. A., Lopez, J. R., Hall, R. I., Hawwa, R., Kashtan, H., Edelist, G., Mallon, J., Kapala, D., Dhamee, M. Saeed, Reynolds, A. C., Olund, T., Entress, J., Kalbfleisch, J., Bell, S. D., Goldberg, M. E., Bracey, B. J., Goldhill, D. R., Bennett, M. H., Emmott, R. S., Innis, R. F., Yate, P. M., Flynn, P. J., Gill, S. S., Saunders, P. R., Geisecke, A. H., Feldman, J. M., Banner, M. J., Siriwardhana, S. A., Kawas, A., Lipton, J. L., Giesecke, A. H., Doyle, D. J., Volgyesi, G. A., Hillier, S. C., Gallagher, J., Hargaden, K., Hamil, M., Cunningham, A. J., Scott, W. A. C., Sielecka, D., Illing, L. H., Jani, K., Scarr, M., Maltby, J. R., Roy, J., McNulty, S. E., Torjman, M., Carey, C., Bracey, B., Markham, K., Durcan, J., Blackstock, D., DaSilva, C. A., Demars, P. D., Montgomery, C. J., Steward, D. J., Sessler, D. I., Laflamme, P., McDevitt, S., Kamal, G. D., Symreng, T., Tatman, D. J., Durcharme, J., Varin, F., Besner, J. G., Dyck, J. B., Chung, F., Arellano, R., Lim, G., Bailey, D. G., Bayliff, C. D., Cunningham, D. G., Ewen, A., Sheppard, S. D., Mahoney, L. T., Bacon, G. S., Rice, L. R., Newman, K., Loe, W., Toth, M., Pilato, M., Classen, K., McDiamid, C., Burrows, F. A., Irish, C. L., Casey, W., Hauser, G. J., Chan, M. M., Midgley, F. M., Holbrook, P. R., Elliott, M. E., Man, W. K., Finegan, B. A., Clanachan, A. S., Hudson, R. J., Thomson, I. R., Burgess, P. M., Rosenbloom, M., Fisher, J. M., O’Connor, J. P., Ralley, F. E., Robbins, G. R., Moote, C. A., Manninen, P. H., English, M., Farmer, C., Scott, A., White, I. W. C., Biehl, D., Donen, N., Mansfield, J., Cohen, M., Wade, J. G., Woodward, C., Ducharme, J., Gerardi, A., Mijares, A., Code, W. E., Hertz, L., Chung, A., Meier, H. M. R., Lautenschlaeger, E., Seyone, C., Wassef, M. R., Devitt, F. H., Cheng, D. C. H., Dyck, B., Chan, V. W. S., Ferrante, F. M., Arthur, G. R., Rice, L., Annallah, R. H., Etches, R. C., Loulmet, D., Lacombe, P., Hollmann, C., Tanguay, M., Blaise, G. A., Lenis, S. G., Fear, D. W., Lang, S. A., Ha, H. C., Germain, H., Neion, A., Dorian, P., Salter, D., Pollick, C., Cervenko, F., Parlow, J., Pym, J., Nakatsu, K., Elliott, D., Miller, D. R., Martineau, R. J., Ewing, D., Martineau, R. J., Knox, J. W. D., Oxorn, D. C., O’Connor, J. P., Whalley, D. G., Rogers, K. H., Kay, J. C., Mazer, C. D., Belo, S. E., Hew-Wing, P., Hew, E., Tessonier, J. M., Thibault, G., Testaert, E., Chartrand, D., Cusson, J. R., Kuchel, O., Larochelle, P., and Couture, J.

Published
1989
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