研究成果 1976 2020

記事
53 引用 (Scopus)

Inhibition of UDP-glucuronosyltransferase 2B7-catalyzed morphine glucuronidation by ketoconazole: Dual mechanisms involving a novel noncompetitive mode

Takeda, S., Kitajima, Y., Ishii, Y., Nishimura, Y., Mackenzie, P. I., Oguri, K. & Yamada, H., 7 24 2006, : : Drug Metabolism and Disposition. 34, 8, p. 1277-1282 6 p.

研究成果: ジャーナルへの寄稿記事

Glucuronosyltransferase
Ketoconazole
Morphine
Liver Microsomes
Nifedipine
3 引用 (Scopus)

Inhibitory Effect of Ethanol and Colchicine on the Intracellular Processing of β-Glucuronidase Which Occurs in the Golgi Complex

Nishimura, Y., Kato, K., Himeno, M. & Oda, K., 1 1 1995, : : Biological and Pharmaceutical Bulletin. 18, 7, p. 938-944 7 p.

研究成果: ジャーナルへの寄稿記事

Glucuronidase
Colchicine
Golgi Apparatus
Ethanol
Enzymes
12 引用 (Scopus)

Inhibitory Effect of Leupeptin on the Intracellular Maturation of Lysosomal Cathepsin L in Primary Cultures of Rat Hepatocytes

Nishimura, Y., Kato, K., Himeno, M. & Furuno, K., 1 1 1995, : : Biological and Pharmaceutical Bulletin. 18, 7, p. 945-950 6 p.

研究成果: ジャーナルへの寄稿記事

Cathepsin L
Enzyme Precursors
Hepatocytes
Molecular Weight
Cysteine Proteinase Inhibitors
34 引用 (Scopus)

Inhibitory effect of norditerpenes on LPS-induced TNF-α production from the Okinawan soft coral, Sinularia sp.

Takaki, H., Koganemaru, R., Iwakawa, Y., Higuchi, R. & Miyamoto, T., 1 1 2003, : : Biological and Pharmaceutical Bulletin. 26, 3, p. 380-382 3 p.

研究成果: ジャーナルへの寄稿記事

Anthozoa
Diterpenes
Lipopolysaccharides
Tumor Necrosis Factor-alpha
Prednisolone
5 引用 (Scopus)

Inhibitory effects of 16-hydroxy-9-oxo-10E,12E,14E-octadecatrienoic acid (Corchorifatty acid B) isolated from Melissa officinalis Linné on melanogenesis

Fujita, H., Hongo, M., Mochizuki, M., Yokoyama, K. & Tanaka, Y., 5 1 2011, : : Experimental Dermatology. 20, 5, p. 420-424 5 p.

研究成果: ジャーナルへの寄稿記事

Melissa
Monophenol Monooxygenase
Degradation
Hypopigmentation
Brefeldin A
16 引用 (Scopus)

Inhibitory effects of adenine nucleotides and related substances on UDP-glucuronosyltransferase: Structure-effect relationships and evidence for an allosteric mechanism

Nishimura, Y., Maeda, S., Ikushiro, S. I., Mackenzie, P. I., Ishii, Y. & Yamada, H., 11 1 2007, : : Biochimica et Biophysica Acta - General Subjects. 1770, 11, p. 1557-1566 10 p.

研究成果: ジャーナルへの寄稿記事

Glucuronosyltransferase
Adenine Nucleotides
Hymecromone
Adenine
Adenosine Monophosphate
86 引用 (Scopus)

Inhibitory effects of SSRIs on IFN-γ induced microglial activation through the regulation of intracellular calcium

Horikawa, H., Kato, T. A., Mizoguchi, Y., Monji, A., Seki, Y., Ohkuri, T., Gotoh, L., Yonaha, M., Ueda, T., Hashioka, S. & Kanba, S., 10 1 2010, : : Progress in Neuro-Psychopharmacology and Biological Psychiatry. 34, 7, p. 1306-1316 11 p.

研究成果: ジャーナルへの寄稿記事

Serotonin Uptake Inhibitors
Microglia
Interferons
Sertraline
Paroxetine
24 引用 (Scopus)
Glucans
Innate Immunity
Insects
Peptide Hydrolases
Hemolymph
1 引用 (Scopus)
Bacterial DNA
Single-Stranded DNA
DNA Replication
Dimers
Escherichia coli
42 引用 (Scopus)

Interaction between cytochrome P450 and other drug-metabolizing enzymes: Evidence for an association of CYP1A1 with microsomal epoxide hydrolase and UDP-glucuronosyltransferase

Taura, K. I., Yamada, H., Hagino, Y., Ishii, Y., Mori, M. A. & Oguri, K., 7 14 2000, : : Biochemical and Biophysical Research Communications. 273, 3, p. 1048-1052 5 p.

研究成果: ジャーナルへの寄稿記事

Epoxide Hydrolases
Glucuronosyltransferase
Cytochrome P-450 CYP1A1
Cytochrome P-450 Enzyme System
Association reactions
34 引用 (Scopus)

Interaction of cytochrome P450 3A4 and UDP-glucuronosyltransferase 2B7: Evidence for protein-protein association and possible involvement of CYP3A4 J-helix in the interaction

Takeda, S., Ishii, Y., Iwanaga, M., Nurrochmad, A., Ito, Y., Mackenzie, P. I., Nagata, K., Yamazoe, Y., Oguri, K. & Yamada, H., 4 1 2009, : : Molecular Pharmacology. 75, 4, p. 956-964 9 p.

研究成果: ジャーナルへの寄稿記事

Cytochrome P-450 CYP3A
Glucuronosyltransferase
Proteins
Antibodies
Glutathione Transferase
59 引用 (Scopus)

Interaction of saposins, acidic lipids, and glucosylceramidase

Morimoto, S., Kishimoto, Y., Tomich, J., Weiler, S., Ohashi, T., Barranger, J. A., Kretz, K. A. & O'Brien, J. S., 2 5 1990, : : Journal of Biological Chemistry. 265, 4, p. 1933-7 5 p.

研究成果: ジャーナルへの寄稿記事

Saposins
Glucosylceramidase
Lipids
Glycoproteins
Enzymes
9 引用 (Scopus)

Intracellular dynamics and fate of a humanized anti-interleukin-6 receptor monoclonal antibody, Tocilizumab

Fujimoto, K., Ida, H., Hirota, Y., Ishigai, M., Amano, J. & Tanaka, Y., 10 1 2015, : : Molecular Pharmacology. 88, 4, p. 660-675 16 p.

研究成果: ジャーナルへの寄稿記事

Interleukin-6 Receptors
Monoclonal Antibodies
Endosomes
Lysosomes
Endocytosis
27 引用 (Scopus)

Intracellular metabolite β-glucosylceramide is an endogenous Mincle ligand possessing immunostimulatory activity

Nagata, M., Izumi, Y., Ishikawa, E., Kiyotake, R., Doi, R., Iwai, S., Omahdi, Z., Yamaji, T., Miyamoto, T., Bamba, T. & Yamasaki, S., 4 18 2017, : : Proceedings of the National Academy of Sciences of the United States of America. 114, 16, p. E3285-E3294

研究成果: ジャーナルへの寄稿記事

Glucosylceramides
C-Type Lectins
Macrophages
Ligands
Dendritic Cells
4 引用 (Scopus)

Intracellular sorting of lysosomal β-glucuronidase is altered due to administaration of dibutyl phosphate

Nishimura, Y., Kato, K., Oda, K., Ishikawa, T., Ikehara, Y. & Himeno, M., 1 1 1995, : : Journal of biochemistry. 118, 1, p. 46-55 10 p.

研究成果: ジャーナルへの寄稿記事

Glucuronidase
Sorting
Rats
Enzymes
Serum
12 引用 (Scopus)

Intracellular targeting of lysosomal cathepsin D in COS cells

Takeshima, H., Sakaguchi, M., Mihara, K., Murakami, K., Omura, T., Himeno, M. & Nishimura, Y., 10 1 1995, : : Journal of biochemistry. 118, 5, p. 981-988 8 p.

研究成果: ジャーナルへの寄稿記事

Cathepsin D
COS Cells
Mutant Proteins
Sorting
Endoplasmic Reticulum
26 引用 (Scopus)

Intracellular transport and processing of lysosomal cathepsin B

Nishimura, Y. & Kato, K., 10 14 1987, : : Biochemical and Biophysical Research Communications. 148, 1, p. 254-259 6 p.

研究成果: ジャーナルへの寄稿記事

Cathepsin B
Lysosomes
Processing
Subcellular Fractions
Golgi Apparatus
27 引用 (Scopus)

Intracellular transport and processing of lysosomal cathepsin H

Nishimura, Y. & Kato, K., 10 14 1987, : : Biochemical and Biophysical Research Communications. 148, 1, p. 329-334 6 p.

研究成果: ジャーナルへの寄稿記事

Cathepsin H
Lysosomes
Subcellular Fractions
Golgi Apparatus
Processing
2 引用 (Scopus)

Intramolecular H-bonds govern the recognition of a flexible peptide by an antibody

Miyanabe, K., Akiba, H., Kuroda, D., Nakakido, M., Kusano-Arai, O., Iwanari, H., Hamakubo, T., Caaveiro, J. M. M. & Tsumoto, K., 7 1 2018, : : Journal of biochemistry. 164, 1, p. 65-76 12 p.

研究成果: ジャーナルへの寄稿記事

Biological Phenomena
Molecular recognition
Peptides
Antibodies
Free energy
51 引用 (Scopus)

Intrinsic nuclear import activity of geminin is essential to prevent re-initiation of DNA replication in Xenopus eggs

Yoshida, K., Takisawa, H. & Kubota, Y., 1 2005, : : Genes to Cells. 10, 1, p. 63-73 11 p.

研究成果: ジャーナルへの寄稿記事

Geminin
Cell Nucleus Active Transport
Xenopus
DNA Replication
Eggs
3 引用 (Scopus)

Introduction of a glycosylation site in the constant region decreases the aggregation of adalimumab Fab

Nakamura, H., Oda-Ueda, N., Ueda, T. & Ohkuri, T., 9 5 2018, : : Biochemical and Biophysical Research Communications. 503, 2, p. 752-756 5 p.

研究成果: ジャーナルへの寄稿記事

Glycosylation
Agglomeration
Density (optical)
Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase
Pichia
2 引用 (Scopus)

Introduction of an N-glycosylation site into UDP-glucuronosyltransferase 2B3 alters its sensitivity to cytochrome P450 3A1-dependent modulation

Nakamura, T., Yamaguchi, N., Miyauchi, Y., Takeda, T., Yamazoe, Y., Nagata, K., Mackenzie, P. I., Yamada, H. & Ishii, Y., 11 14 2016, : : Frontiers in Pharmacology. 7, NOV, 427.

研究成果: ジャーナルへの寄稿記事

Glucuronosyltransferase
Glycosylation
Cytochrome P-450 Enzyme System
Cytochrome P-450 CYP3A
Hymecromone
29 引用 (Scopus)

Inulavosin, a melanogenesis inhibitor, leads to mistargeting of tyrosinase to lysosomes and accelerates its degradation

Fujita, H., Motokawa, T., Katagiri, T., Yokota, S., Yamamoto, A., Himeno, M. & Tanaka, Y., 6 2009, : : Journal of Investigative Dermatology. 129, 6, p. 1489-1499 11 p.

研究成果: ジャーナルへの寄稿記事

Monophenol Monooxygenase
Lysosomes
Melanosomes
Degradation
Melanins
5 引用 (Scopus)

Inulavosin and its benzo-derivatives, melanogenesis inhibitors, target the copper loading mechanism to the active site of tyrosinase

Fujita, H., Menezes, J. C. J. M. D. S., Santos, S. M., Yokota, S., Kamat, S. P., Cavaleiro, J. A. S., Motokawa, T., Kato, T., Mochizuki, M., Fujiwara, T., Fujii, Y. & Tanaka, Y., 5 2014, : : Pigment Cell and Melanoma Research. 27, 3, p. 376-386 11 p.

研究成果: ジャーナルへの寄稿記事

Monophenol Monooxygenase
Copper
Catalytic Domain
Derivatives
Lysosomes
21 引用 (Scopus)

Investigation of interfacial behavior of glycyrrhizin with a lipid raft model via a Langmuir monolayer study

Sakamoto, S., Nakahara, H., Uto, T., Shoyama, Y. & Shibata, O., 4 1 2013, : : Biochimica et Biophysica Acta - Biomembranes. 1828, 4, p. 1271-1283 13 p.

研究成果: ジャーナルへの寄稿記事

Glycyrrhizic Acid
Monolayers
Cholesterol
Lipids
Tromethamine

Investigation of the endoplasmic reticulum localization of UDP-glucuronosyltransferase 2B7 with systematic deletion mutants

Miyauchi, Y., Kimura, S., Kimura, A., Kurohara, K., Hirota, Y., Fujimoto, K., Mackenzie, P. I., Tanaka, Y. & Ishii, Y., 5 1 2019, : : Molecular Pharmacology. 95, 5, p. 551-562 12 p.

研究成果: ジャーナルへの寄稿記事

Glucuronosyltransferase
Endoplasmic Reticulum
lysyllysine
Calnexin
Microscopy
34 引用 (Scopus)

Investigation of the structural basis for thermostability of DNA- binding protein HU from Bacillus stearothermophilus

Kawamura, S., Abe, Y., Ueda, T., Masumoto, K., Imoto, T., Yamasaki, N. & Kimura, M., 8 7 1998, : : Journal of Biological Chemistry. 273, 32, p. 19982-19987 6 p.

研究成果: ジャーナルへの寄稿記事

Geobacillus stearothermophilus
DNA-Binding Proteins
Bacilli
Circular Dichroism
Amino Acids
24 引用 (Scopus)

In vitro binding study of adaptor protein complex (AP-1) to lysosomal targeting motif (LI-motif)

Fujita, H., Saeki, M., Yasunaga, K., Ueda, T., Imoto, T. & Himeno, M., 2 5 1999, : : Biochemical and Biophysical Research Communications. 255, 1, p. 54-58 5 p.

研究成果: ジャーナルへの寄稿記事

Adaptor Protein Complex 1
Transcription Factor AP-1
Lysosome-Associated Membrane Glycoproteins
Isoleucine
Leucine
22 引用 (Scopus)

In vitro biosynthesis of the lysosomal cathepsin H

Nishimura, Y. & Kato, K., 7 15 1987, : : Biochemical and Biophysical Research Communications. 146, 1, p. 159-164 6 p.

研究成果: ジャーナルへの寄稿記事

Cathepsin H
Biosynthesis
Enzyme Precursors
Membranes
Polyribosomes
37 引用 (Scopus)

Involvement of COX-1 and up-regulated prostaglandin e synthases in phosphatidylserine liposome-induced prostaglandin E2 production by microglia

Zhang, J., Fujii, S., Wu, Z., Hashioka, S., Tanaka, Y., Shiratsuchi, A., Nakanishi, Y. & Nakanishi, H., 3 1 2006, : : Journal of Neuroimmunology. 172, 1-2, p. 112-120 9 p.

研究成果: ジャーナルへの寄稿記事

Cyclooxygenase 1
Phosphatidylserines
Microglia
Prostaglandin-Endoperoxide Synthases
Dinoprostone
6 引用 (Scopus)

Involvement of histidine in complex formation of PriB and single-stranded DNA

Fujiyama, S., Abe, Y., Takenawa, T., Aramaki, T., Shioi, S., Katayama, T. & Ueda, T., 2 1 2014, : : Biochimica et Biophysica Acta - Proteins and Proteomics. 1844, 2, p. 299-307 9 p.

研究成果: ジャーナルへの寄稿記事

Single-Stranded DNA
Histidine
Chemical shift
Biomolecular Nuclear Magnetic Resonance
Dimers
25 引用 (Scopus)

Involvement of the Escherichia coli folate-binding protein YgfZ in RNA modification and regulation of chromosomal replication initiation

Ote, T., Hashimoto, M., Ikeuchi, Y., Su'etsugu, M., Suzuki, T., Katayama, T. & Kato, J. I., 1 1 2006, : : Molecular Microbiology. 59, 1, p. 265-275 11 p.

研究成果: ジャーナルへの寄稿記事

Folic Acid
Carrier Proteins
RNA
Escherichia coli
Transfer RNA
18 引用 (Scopus)

Irciniasulfonic acid B, a novel taurine conjugated fatty acid derivative from a Japanese marine sponge, Ircinia sp.

Emura, C., Higuchi, R. & Miyamoto, T., 6 12 2006, : : Tetrahedron. 62, 24, p. 5682-5685 4 p.

研究成果: ジャーナルへの寄稿記事

Taurine
Military Personnel
Porifera
Fatty Acids
Derivatives
13 引用 (Scopus)

Isoflavonoid production in a hairy roots culture of Pueraria candollei

Udomsuk, L., Jarukamjorn, K., Tanaka, H. & Putalun, W., 1 1 2009, : : Zeitschrift fur Naturforschung - Section C Journal of Biosciences. 64, 9-10, p. 687-691 5 p.

研究成果: ジャーナルへの寄稿記事

Pueraria
Sucrose
Agrobacterium
Genistein
Growth
41 引用 (Scopus)

Isolation and Characterization of 101-Succinimide Lysozyme That Possesses the Cyclic Imide at Asp101-Gly102

Tomizawa, H., Ueda, T., Imoto, T. & Yamada, H., 7 1 1994, : : Biochemistry. 33, 29, p. 8770-8774 5 p.

研究成果: ジャーナルへの寄稿記事

Imides
Muramidase
succinimide
Cations
Hydrolysis
39 引用 (Scopus)

Isolation and Characterization of 101-β-Lysozyme That Possesses the β-Aspartyl Sequence at Aspartic Acid-101

Yamada, H., Ueda, T., Kuroki, R., Fukumura, T., Yasukochi, T., Hirabayashi, T., Fujita, K. & Imoto, T., 12 1 1985, : : Biochemistry. 24, 27, p. 7953-7959 7 p.

研究成果: ジャーナルへの寄稿記事

Muramidase
Aspartic Acid
Biochemistry
Diatomaceous Earth
Derivatives

Isolation and characterization of inhibitory factors of DNA polymerase III holoenzyme from Escherichia coli

Hase, M., Mizushima, T., Katayama, T. & Sekimizu, K., 8 1 1995, : : FEMS microbiology letters. 130, 2-3, p. 215-220 6 p.

研究成果: ジャーナルへの寄稿記事

DNA Polymerase III
DNA Polymerase I
Holoenzymes
DNA-Directed DNA Polymerase
Escherichia coli
11 引用 (Scopus)

Isolation and characterization of novel cold-sensitive dnaA mutants of Escherichia coli

Guo, L., Katayama, T., Seyama, Y., Sekimizu, K. & Miki, T., 7 15 1999, : : FEMS microbiology letters. 176, 2, p. 357-366 10 p.

研究成果: ジャーナルへの寄稿記事

Escherichia coli
Plasmids
Phenotype
Mutation
Manganese
3 引用 (Scopus)

Isolation and identification of new anthraquinones from Rhamnus alaternus L and evaluation of their free radical scavenging activity

Ben Ammar, R., Miyamoto, T., Chekir-Ghedira, L., Ghedira, K. & Lacaille-Dubois, M. A., 1 17 2019, : : Natural Product Research. 33, 2, p. 280-286 7 p.

研究成果: ジャーナルへの寄稿記事

Rhamnus
Anthraquinones
anthraquinones
Scavenging
Free Radicals
40 引用 (Scopus)

Isolation and sequencing of a cDNA clone encoding 107 kDa sialoglycoprotein in rat liver lysosomal membranes

Himeno, M., Noguchi, Y., Sasaki, H., Tanaka, Y., Furuno, K., Kono, A., Sakaki, Y. & Kato, K., 2 27 1989, : : FEBS Letters. 244, 2, p. 351-356 6 p.

研究成果: ジャーナルへの寄稿記事

Sialoglycoproteins
Liver
Rats
Pancreas
Glycoproteins
20 引用 (Scopus)

Isolation and sequencing of a cDNA clone encoding 96 kDa sialoglycoprotein in rat liver lysosomal membranes

Noguchi, Y., Himeno, M., Sasaki, H., Tanaka, Y., Kono, A., Sakaki, Y. & Kato, K., 11 15 1989, : : Biochemical and Biophysical Research Communications. 164, 3, p. 1113-1120 8 p.

研究成果: ジャーナルへの寄稿記事

Sialoglycoproteins
Liver
Rats
Complementary DNA
Clone Cells
35 引用 (Scopus)

Isolation and sequencing of a cDNA clone encoding rat liver lysosomal cathepsin D and the structure of three forms of mature enzymes

Fujita, H., Tanaka, Y., Noguchi, Y., Kono, A., Himeno, M. & Kato, K., 8 30 1991, : : Biochemical and Biophysical Research Communications. 179, 1, p. 190-196 7 p.

研究成果: ジャーナルへの寄稿記事

Cathepsin D
Liver
Rats
Complementary DNA
Clone Cells
26 引用 (Scopus)

Isolation and sequencing of a cDNA clone encoding the 85 kDa human lysosomal sialoglycoprotein (hLGP85) in human metastatic pancreas islet tumor cells

Fujita, H., Takata, Y., Kono, A., Tanaka, Y., Takahashi, T., Himeno, M. & Kato, K., 4 30 1992, : : Biochemical and Biophysical Research Communications. 184, 2, p. 604-611 8 p.

研究成果: ジャーナルへの寄稿記事

Sialoglycoproteins
Islet Cell Adenoma
Rats
Tumors
Pancreas
10 引用 (Scopus)

Isolation and structure elucidation of GM4-type gangliosides from the Okinawan starfish Protoreaster nodosus

Pan, K., Tanaka, C., Inagaki, M., Higuchi, R. & Miyamoto, T., 11 1 2012, : : Marine Drugs. 10, 11, p. 2467-2480 14 p.

研究成果: ジャーナルへの寄稿記事

Starfish
Ceramides
Gangliosides
GM4 ganglioside
14 引用 (Scopus)

Isolation and structure of a galactocerebroside from the sea cucumber bohadschia argus

Ikeda, Y., Inagaki, M., Yamada, K., Zhang, X. W., Zhang, B., Miyamoto, T. & Higuchi, R., 3 1 2009, : : Chemical and Pharmaceutical Bulletin. 57, 3, p. 315-317 3 p.

研究成果: ジャーナルへの寄稿記事

Sea Cucumbers
Cerebrosides
Glucosylceramides
High Pressure Liquid Chromatography
Lipids
11 引用 (Scopus)

Isolation and structure of a GD3-type ganglioside molecular species possessing neuritogenic activity from the starfish Luidia maculata

Kawatake, S., Inagaki, M., Isobe, R., Miyamoto, T. & Higuchi, R., 8 1 2004, : : Chemical and Pharmaceutical Bulletin. 52, 8, p. 1002-1004 3 p.

研究成果: ジャーナルへの寄稿記事

Starfish
phytosphingosine
Ceramides
Hydroxy Acids
Gangliosides
19 引用 (Scopus)

Isolation and structure of a monomethylated ganglioside possessing neuritogenic activity from the ovary of the sea urchin Diadema setosum

Yamada, K., Tanabe, K., Miyamoto, T., Kusumoto, T., Inagaki, M. & Higuchi, R., 5 19 2008, : : Chemical and Pharmaceutical Bulletin. 56, 5, p. 734-738 5 p.

研究成果: ジャーナルへの寄稿記事

Sea Urchins
Gangliosides
Ovary
phytosphingosine
Ceramides
31 引用 (Scopus)

Isolation and structure of biologically active gangliosides from the sea cucumber Holothuria pervicax

Yamada, K., Harada, Y., Nagaregawa, Y., Miyamoto, T., Isobe, R. & Higuchi, R., 11 1998, : : European Journal of Organic Chemistry. 11, p. 2519-2525 7 p.

研究成果: ジャーナルへの寄稿記事

Gangliosides
chloroform
cultured cells
rats
isolation
44 引用 (Scopus)

Isolation and structure of biologically active glycosphingolipids from the sea cucumber Cucumaria echinata

Yamada, K., Hara, E., Miyamoto, T., Higuchi, R., Isobe, R. & Honda, S., 2 1998, : : European Journal of Organic Chemistry. 2, p. 371-378 8 p.

研究成果: ジャーナルへの寄稿記事

Cerebrosides
lethality
Glycosphingolipids
chloroform
cultured cells
7 引用 (Scopus)

Isolation and structure of hematoside-type ganglioside from the starfish linckia laevigata

Inagaki, M., Saito, T., Miyamoto, T. & Higuchi, R., 2 1 2009, : : Chemical and Pharmaceutical Bulletin. 57, 2, p. 204-206 3 p.

研究成果: ジャーナルへの寄稿記事

G(M3) Ganglioside
Starfish
phytosphingosine
Gangliosides
Ceramides