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41.
Kim YH; de Kretser DM; Temple-Smith PD; Hearn MT; McFarlane JR 《Molecular human reproduction》1997,3(4):307-313
Using mechanical and chemical dissection methods, fibrous sheath was
isolated both from normal ejaculated human spermatozoa and from rabbit
cauda epididymal spermatozoa. The same techniques did not produce a pure
preparation of fibrous sheath from ejaculated rabbit spermatozoa,
suggesting that further cross-linking and stabilization of sperm structures
occurs in response to components of the seminal plasma. The isolation
procedures were monitored by phase contrast microscopy and the purity of
the fibrous sheath was verified by electron microscopy. Sodium dodecyl
sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of isolated human
fibrous sheath revealed at least 14 protein bands of which the most
intensely stained were of molecular weight 84, 72, 66.2, 57, 32 and 28.5
kDa. The rabbit fibrous sheath revealed at least 10 protein bands, of which
the most intensely stained were 35.2, 32.7 and 28.5 kDa. The amino acid
composition of the purified fibrous sheath from human and rabbit
spermatozoa was similar, being high in aspartic acid and/or asparagine and
glutamic acid and/or glutamine, serine, alanine, leucine, lysine and
glycine, but low in histidine, tyrosine and isoleucine. This composition is
similar to that reported for the rat and suggests that mammalian sperm tail
fibrous sheaths are composed of similar types of proteins, although there
are apparent differences in protein components between species.
相似文献
42.
The CTLA-4 gene region of chromosome 2q33 is linked to, and associated with, type 1 diabetes. Belgian Diabetes Registry 总被引:8,自引:1,他引:8
Nistico L; Buzzetti R; Pritchard LE; Van der Auwera B; Giovannini C; Bosi E; Larrad MT; Rios MS; Chow CC; Cockram CS; Jacobs K; Mijovic C; Bain SC; Barnett AH; Vandewalle CL; Schuit F; Gorus FK; Tosi R; Pozzilli P; Todd JA 《Human molecular genetics》1996,5(7):1075-1080
Susceptibility to autoimmune insulin-dependent (type 1) diabetes mellitus
is determined by a combination of environmental and genetic factors, which
include variation in MHC genes on chromosome 6p21 (IDDM1) and the insulin
gene on chromosome 11p15 (IDDM2). However, linkage to IDDM1 and IDDM2
cannot explain the clustering of type 1 diabetes in families, and a role
for other genes is inferred. In the present report we describe linkage and
association of type 1 diabetes to the CTLA-4 gene (cytotoxic T lymphocyte
associated-4) on chromosome 2q33 (designated IDDM12). CTLA-4 is a strong
candidate gene for T cell- mediated autoimmune disease because it encodes a
T cell receptor that mediates T cell apoptosis and is a vital negative
regulator of T cell activation. In addition, we provide supporting evidence
that CTLA-4 is associated with susceptibility to Graves' disease, another
organ- specific autoimmune disease.
相似文献
43.
Induction of a differentiated ciliated cell phenotype in primary cultures of Fallopian tube epithelium 总被引:5,自引:1,他引:5
Human Fallopian tubal epithelial cells in culture lose morphological
features associated with the epithelium in situ and the extent to which
they retain their in-vivo phenotype or function is unknown. In order to
address this question, immunocytochemical markers were identified which
distinguish secretory (HMFG2+, LhS28-) from ciliated (HMFG2-, LhS28+)
epithelial cells in tissue sections of Fallopian tube. These markers were
used to analyse the phenotype of tubal cells in vitro. Primary cultures of
human tubal epithelial cells were seeded onto glass and grown to confluence
before addition of oestradiol-17beta. In the absence of hormone, tubal
epithelial cells expressed cytokeratins and nuclear receptors for oestrogen
and progesterone and adopted a homogeneous (HMFG2+, LhS28-) secretory cell
phenotype. Following the addition of oestradiol-17beta, a proportion of
cells became positive for LhS28. The induction of a ciliated epithelial
cell phenotype was confirmed by scanning electron microscopy, where on
permeable collagen membranes, approximately one-third of tubal epithelial
cells became ciliated in the presence of oestradiol-17beta. We suggest that
in vitro, tubal epithelial cells adopt an immature secretory-like phenotype
and that oestrogen can induce differentiation to a ciliated epithelial cell
phenotype.
相似文献
44.
Okano H Shiraki K Inoue H Kawakita T Deguchi M Sugimoto K Sakai T Murata K Nakano T Enjoji M 《International journal of molecular medicine》2003,12(6):867-870
PPARgamma is known to induce apoptosis in malignant tumor cells, but the mechanism of this induction is not well understood. We investigated induction of apoptosis with 15-Deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2), a PPARgamma ligand, in cholangio cell carcinoma (CCC) cells (RBE, ETK-1 or HuCCT-1). Apoptosis was induced in RBE and ETK-1 cells with 15d-PGJ2, but not in HuCCT-1 cells, although PPARgamma was expressed in all CCC cells. Apoptosis-related proteins were also expressed, including FLIP, bclx, Apaf-1 and XIAP, but expression levels differed among the three cell lines. RBE cells treated with 15d-PGJ2 showed caspase activation, and it appeared that PPARgamma-induced apoptosis was dependent on caspase activation. However, neither ETK-1 nor HuCCT-1 cells showed significant activation of caspase-8 or -3 with 15d-PGJ2 treatment, raising the possibility of a caspase-independent apoptosis induction pathway. XIAP was down-regulated by 15d-PGJ2 in all three CCC cell lines. Therefore, 15d-PGJ2 induces apoptosis in CCC cells via caspase-dependent or independent pathways. 15d-PGJ2 may also induce down-regulation of XIAP and may promote caspase cascade activation through TNF-family receptor signaling pathways. 相似文献
45.
Relationship between lipoxygenase and human testicular cancer 总被引:7,自引:0,他引:7
Yoshimura R Matsuyama M Mitsuhashi M Takemoto Y Tsuchida K Kawahito Y Sano H Nakatani T 《International journal of molecular medicine》2004,13(3):389-393
The metabolism of arachidonic acid by either the cyclooxygenase (COX) or lipoxygenase (LOX) pathway generates eicosanoids, which have been implicated in the pathogenesis of a variety of human diseases, including cancer. They are now believed to play important roles in tumor promotion, progression, and metastasis, and the involvement of LOX expression and function in tumor growth and metastasis has been reported in human tumor cell lines. Expressions of 5-LOX and 12-LOX in human testicular cancer (TC), and normal testis (NT) tissues were examined, as well as effects of their inhibitors on cell proliferation in TC cell line. Expressions of 5-LOX and 12-LOX were detected by immunohistochemistry. Effects of LOX inhibitors on TC cell growth were examined by MTT assay. While 5-LOX and 12-LOX expressions were slightly detected in NT tissues, expressions of 5-LOX and 12-LOX were significant detected in TC tissues by immunohistochemistry. The LOX inhibitors inhibited the growth of TC cells. LOX is induced in TC, and results may suggest that LOXs are essential for cell growth of TC cells. 相似文献
46.
Keiichi Kimura Yoshiaki Inaki Kiichi Takemoto 《Macromolecular chemistry and physics.》1977,178(2):317-328
The initiation mechanism of vinyl polymerization by a copper(II) chelate of poly(vinyl alcohol) was studied in aqueous solution in the presence of carbon tetrachloride, in order to determine the free radical species formed during the initiation step. Trichloromethyl radicals were ascertained to be the main initiation species, by spin trapping and gelation experiments. Differences in polymerization activity between methyl methacrylate and acrylonitrile are discussed. 相似文献
47.
Fumi Takemoto Takeo Satoh Herbert T. Cohen Adrian I. Katz 《Pflügers Archiv : European journal of physiology》1991,419(3-4):243-248
Dopamine exerts numerous actions on the kidney but the precise location of its receptor subtypes along the nephron is unknown. Using a microassay we determined the specific binding of 125I-Sch 23982, a specific and selective dopamine-1 (DA1) receptor antagonist, to microdissected glomeruli and tubule segments. Binding of 125I-Sch 23982 in the proximal convoluted tubule (PCT) was timeand concentration dependent, saturable and reversible. The linear Scatchard plot of saturation experiments suggested binding to a single site with an apparent K
d of 16.7 nM and B
max of 0.4 fmol·mm–1 in the PCT, and 6.2 nM and 0.1 fmol·mm–1 in the cortical collecting tubule (CCT). Mapping of DA1 binding sites along the nephron revealed their presence in each of the segments examined, albeit in markedly different concentrations: the highest specific binding was measured in PCT followed by the pars recta. Binding was less in the distal nephron, and least in the medullary and cortical thick ascending limb. Modest binding was also detected in glomeruli. In cortical collecting tubules competition studies with unlabeled dopamine and probes for DA1 (Sch 23390, fenoldopam), DA2 (domperidone, S-sulpiride), serotonergic (serotonin, ketanserin, mianserin), and -(phentolamine) and -(propranolol) adrenergic receptors indicated a rank-order potency for displacement of 125I-Sch 23982 binding, consistent with labeling of DA1 receptors. Dopamine inhibited Na/K-ATPase both in PCT and CCT, an effect duplicated in the latter segment by the DA1 agonist fenoldopam, and blocked by the DA1 antagonist Sch 23390. These results demonstrate specific DA1 binding sites in a nonhomogeneous pattern along the entire nephron, and suggest that dopamine may exert its effect on Na transport in distal as well as in proximal nephron segments. 相似文献
48.
Keiichi Kimura Yoshiaki Inaki Kiichi Takemoto 《Macromolecular chemistry and physics.》1974,175(1):83-93
In order to clarify the mechanism of catalysis of polyvinylamine-copper(II) chelates on the initiation of vinyl polymerizations, stability constants of these chelates were measured by applying a modification of BJERRUM'S method, and each concentration of the chemical species was estimated on the basis of the chelate theory. From these results, the activity of the polyvinylamine-copper(II) chelates for the polymerization of acrylonitrile and methyl methacrylate at different pH values was discussed. 相似文献
49.
Keiichi Kimura Yoshiaki Inaki Kiichi Takemoto 《Macromolecular chemistry and physics.》1975,176(8):2241-2249
The polymerization of acrylonitrile (AN) and of methyl methacrylate (MMA) initiated by various copper(II) chelates was studied in the presence of carbon tetrachloride. Several vinylamine (VAm)/vinyl alcohol (VA) copolymers with different contents of NH2 and OH bearing monomeric units were chosen as polymer ligands as well as polyvinylamine (PVAm)/poly(vinyl alcohol) (PVA) mixtures (of equal NH2 and OH group contents as the corresponding copolymers), PVAm, and PVA. The activity of the used polymer chelates to initiate the AN and the MMA polymerization was compared at various pH values of the reaction systems. For the polymerization of MMA, the VAm/VA copolymer systems showed a higher activity than the PVAm chelate containing the same amount of NH2 groups, contrary to the case of the polymerization of AN, where the polymerization activity showed a reverse behavior. The initiation mechanism is discussed. 相似文献
50.
Keiichi Kimura Yoshiaki Inaki Kiichi Takemoto 《Macromolecular chemistry and physics.》1975,176(8):2225-2239
Chelate formation of vinylamine/vinyl alcohol copolymers with copper(II) was studied both by the spectrophotometric and by titrimetric methods. For comparison, polyvinylamine/poly(vinyl alcohol) mixtures were also taken up for measurements. In the case of the copolymer systems, copper(II) ions were found to be coordinated exclusively by nitrogen atoms of the copolymer ligand. The complexation constants of the chelates were determined by applying the modified Bjerrum method, in neglect of the acid dissociation of hydroxy groups in the copolymers. It was found that the copolymer/Cu(II) chelates tend to be unstable with decreasing contents of NH2 groups in the copolymers. In the homopolymer mixture systems, copper(II) ions are not coordinated by the oxygen atoms of poly(vinyl alcohol), but only by the nitrogen atoms of polyvinylamine. 相似文献