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排序方式: 共有103条查询结果,搜索用时 26 毫秒
81.
Ikeda I Kobayashi M Hamada T Tsuda K Goto H Imaizumi K Nozawa A Sugimoto A Kakuda T 《Journal of agricultural and food chemistry》2003,51(25):7303-7307
It has been known that tea catechins, (-)-epicatechin (1), (-)-epigallocatechin (2), (-)-epicatechin gallate (3), and (-)-epigallocatechin gallate (4) are epimerized to(-)-catechin (5), (-)-gallocatechin (6), (-)-catechin gallate (7), and (-)-gallocatechin gallate (8), respectively, during retort pasteurization. We previously reported that tea catechins, mainly composed of 3 and 4, effectively inhibit cholesterol absorption in rats. In this study, the effect of heat-epimerized catechins on cholesterol absorption was compared with tea catechins. Both tea catechins and heat-epimerized catechins lowered lymphatic recovery of cholesterol in rats cannulated in the thoracic duct and epimerized catechins were more effective than tea catechins. The effect of purified catechins on micellar solubility of cholesterol was examined in an in vitro study. The addition of gallate esters of catechins reduced micellar solubility of cholesterol by precipitating cholesterol from bile salt micelles. Compounds 7 and 8 were more effective to precipitate cholesterol than 3 and 4, respectively. These observations strongly suggest that heat-epimerized catechins may be more hypocholesterolemic than tea catechins. 相似文献
82.
Ferulic acid (FA) and p-coumaric acid (CA) are absorbed by the monocarboxylic acid transporter (MCT) in Caco-2 cells, although gallic acid (GA) is not. Therefore, the MCT is selective for certain phenolic acids. Absorption of orally administered CA and GA in rats was studied to obtain serum pharmacokinetic profiles and to investigate their intestinal absorption characteristics in vivo. Rats were administered 100 micromol/kg body weight of CA and GA, and blood was collected from the portal vein and abdominal artery after administration. CA, GA, and their metabolites were quantified with a highly selective and sensitive coulometric detection method using high-performance liquid chromatography-electrochemical detection. Ingested CA was rapidly absorbed in the gastrointestinal tract in an intact form. The serum concentration of intact CA in the portal vein peaked 10 min after dosing (C(max) was 165.7 micromol/L). In contrast, GA was slowly absorbed, with a t(max) for intact GA of 60 min and a C(max) of 0.71 micromol/L. The area under the curve for intact CA and GA was calculated from the serum concentration profile in the portal vein to be 2991.3 and 42.6 micromol min L(-)(1), respectively. The relative bioavailability of CA against GA was about 70. This is the first demonstration that absorption efficiency of CA is much higher than that of GA in vivo. The absorption characteristics of CA are clearly different from those of GA. These findings are in good agreement with the results obtained in vitro using a Caco-2 cell system. 相似文献
83.
Yumi Umeda Tatsuya Kasai Misae Saito Hitomi Kondo Tadao Toya Shigetoshi Aiso Hirokazu Okuda Tomoshi Nishizawa Shoji Fukushima 《Journal of toxicologic pathology》2013,26(2):131-140
To evaluate pulmonary toxicity of multi-walled carbon nanotubes (MWCNTs), F344 rats of
both sexes were exposed by inhalation to 0.2, 1 or 5 mg/m3 MWCNT aerosol for 6
h/day, 5 days/week for 2 weeks using a whole-body exposure system. At the end of the
2-week exposure period, one-half of the rats were necropsied, and at the end of an
additional 4-week postexposure period, the remaining rats were necropsied. MWCNTs were
deposited in the lungs of all MWCNT-exposed groups and mostly remained in the lungs
throughout the 4-week postexposure period. Granulomatous changes in the lung were found in
the rats exposed to 5 mg/m3 MWCNTs, and these changes were slightly aggravated
at the end of the 4-week postexposure period. In the bronchoalveolar lavage fluid (BALF),
the numbers of neutrophils, percentages of bi- and multinucleated alveolar macrophages,
levels of ALP activity and concentrations of total protein and albumin were elevated in
the rats exposed to 1 and 5 mg/m3 MWCNTs. At the end of the 4-week postexposure
period, the values of the BALF parameters tended to remain elevated. In addition, goblet
cell hyperplasias in the nasal cavity and nasopharynx were observed in the rats exposed to
1 and 5 mg/m3 MWCNTs, but these lesions had largely regressed by the end of the
postexposure period. Based on the histopathological and inflammatory changes, the
no-observed-adverse-effect level (NOAEL) for inhalation of MWCNTs for 2 weeks was 0.2
mg/m3. 相似文献
84.
Generation of transgenic rats expressing enhanced green fluorescent protein in gonadotropin-releasing hormone neurons 总被引:3,自引:0,他引:3
Fujioka H Suzuki M Yamanouchi K Ohta A Nagashima H Kato M Nishihara M 《The Journal of reproduction and development》2003,49(6):523-529
Hypothalamic gonadotropin-releasing hormone (GnRH) neurons govern reproductive function by controlling the release of gonadotropins from the pituitary. To facilitate identification of living GnRH neurons, here we attempted to generate transgenic rats that express enhanced green fluorescent protein (EGFP) in GnRH neurons. About 3 kb of rat GnRH promoter region was inserted into the EGFP reporter cassette, and the expression of EGFP fluorescence was confirmed in several cell lines following transient transfection. Then we successfully generated a transgenic rat by injecting linearized GnRH-EGFP transgene into the pronuclei of fertilized oocytes. The GnRH-EGFP transgenic rats expressed EGFP in the brain, but not in the ovary, testis or thymus. Immunohistochemical examination revealed that detectable EGFP fluorescence was confined to the cell body of GnRH-immunoreactive neurons in the septum and preoptic area, while no EGFP signal was discernible in the median eminence where abundant GnRH-immunoreactive fibers were observed. The mean percentage of EGFP-positive cells in the GnRH-positive cells was 76.3%. The GnRH-EGFP transgenic rats generated in the present study will enable characterization of properties of individual GnRH neurons. 相似文献
85.
Naotaka ISHIGURO Motoki SASAKI Mitsuhiro IWASA Nobuo SHIGEHARA Hitomi HONGO Tomoko ANEZAKI Vu The LONG Phan Xuan HAO Hguyen Xuan TRACH Nguyen Huu NAM Vu Ngoc THANH 《Animal Science Journal》2008,79(6):655-664
In the present study, we used morphological and genetic analyzes to distinguish bones of domestic boars from those of wild boars. We analyzed 65 Sus bones (cranium, mandible and teeth) stored in three research institutes in Vietnam and in a village in Vietnam. Based on comparison of bucco‐lingual measurements of mandibular parts, the 58 specimens were morphologically classified into two size groups: a large bone group and a small bone group. Analysis of 572‐bp mitochondrial DNA (mtDNA) sequences indicated that the large bones had genetic links to wild boar lineage including Ryukyu, Taiwan and Korean wild boars, and that the small bone group was closely related to East Asian domestic pigs. The phylogenetic analysis and parsimonious networks constructed among mtDNA haplotypes belonging to Ryukyu wild boar lineage showed that the Ryukyu wild boar is closely related to the Vietnamese wild boars, and uniquely miniaturized on their islands after the Ryukyu archipelago became isolated from the Asian continent. 相似文献
86.
Adachi S Yamada S Takatsu Y Matsui H Kinoshita M Takase K Sugiura H Ohtaki T Matsumoto H Uenoyama Y Tsukamura H Inoue K Maeda K 《The Journal of reproduction and development》2007,53(2):367-378
Metastin/kisspeptin, the KiSS-1 gene product, has been identified as an endogenous ligand of GPR54 that reportedly regulates GnRH/LH surges and estrous cyclicity in female rats. The aim of the present study was to determine if metastin/kisspeptin neurons are a target of estrogen positive feedback to induce GnRH/LH surges. We demonstrated that preoptic area (POA) infusion of the anti-rat metastin/kisspeptin monoclonal antibody blocked the estrogen-induced LH surge, indicating that endogenous metastin/kisspeptin released around the POA mediates the estrogen positive feedback effect on GnRH/LH release. Metastin/kisspeptin neurons in the anteroventral periventricular nucleus (AVPV) may be responsible for mediating the feedback effect because the percentage of c-Fos-expressing KiSS-1 mRNA-positive cells to total KiSS-1 mRNA-positive cells was significantly higher in the afternoon than in the morning in the anteroventral periventricular nucleus (AVPV) of high estradiol (E(2))-treated females. The percentage of c-Fos-expressing metastin/kisspeptin neurons was not different between the afternoon and morning in the arcuate nucleus (ARC). Most of the KiSS-1 mRNA expressing cells contain ERalpha immunoreactivity in the AVPV and ARC. In addition, AVPV KiSS-1 mRNA expressions were highest in the proestrous afternoon and lowest in the diestrus 1 in females and were increased by estrogen treatment in ovariectomized animals. On the other hand, the ARC KiSS-1 mRNA expressions were highest at diestrus 2 and lowest at proestrous afternoon and were increased by ovariectomy and decreased by high estrogen treatment. Males lacking the surge mode of GnRH/LH release showed no obvious cluster of metastin/kisspeptin-immunoreactive neurons in the AVPV when compared with high E(2)-treated females, which showed a much greater density of these neurons. Taken together, the present study demonstrates that the AVPV metastin/kisspeptin neurons are a target of estrogen positive feedback to induce GnRH/LH surges in female rats. 相似文献
87.
Fujioka H Yamanouchi K Akema T Nishihara M 《The Journal of reproduction and development》2007,53(2):323-331
Gonadotropin-releasing hormone (GnRH) neurons arise in the olfactory placode, migrate into the preoptic area (POA), and then extend axons to the median eminence during embryogenesis. Little information is available concerning the properties of GnRH neurons during the late gestational period when GnRH neurons reach the POA and form neuronal networks, although many studies have examined such properties during earlier developmental stages or the postnatal period. The present study was performed to elucidate the involvement of gamma-aminobutyric acid (GABA), one of the major neurotransmitters modifying GnRH neural activity, in regulation of GnRH gene expression on embryonic day 18.5 (E18.5) using transgenic rats expressing enhanced green fluorescence protein (EGFP) under the control of GnRH promoter. First, using RT-PCR, the mRNA of two isoforms of the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD), GAD65 and GAD67 was detected in E18.5 embryonic POA-containing tissues. GAD67-positive cells were also demonstrated in close vicinity to GnRH-positive cells by immunohistochemistry, and immunoreactivity for both the GABA-A and GABA-B receptor subunits was detected in GnRH neurons. Next, primary cultures derived from anterior hypothalamic tissue of E18.5 embryos were prepared, and the effects of GABA and its agonists on GnRH promoter activity were evaluated using EGFP expression as a marker. GABA and the GABA-A receptor agonist muscimol, but not the GABA-B receptor agonist baclofen, significantly increased the EGFP-positive/GnRH-positive cell ratio. These results suggest that GABA plays a role in stimulating GnRH gene expression through GABA-A receptors in embryonic GnRH neurons in late gestational stages. 相似文献
88.
89.
Akiyoshi EGASHIRA Nobuhiko YAMAUCHI Keiko TANAKA Chihiro MINE Hitomi OTSUBO Masao MURAKAMI Md. Rashedul ISLAM Misako OHTSUKA Naomi YOSHIOKA Takashi KURAMOTO 《The Journal of reproduction and development》2015,61(6):595-600
The presence of multinucleated blastomeres (MNBs) in embryos is associated with poor developmental
competence in assisted reproductive technologies. This phenomenon is observed not only in humans but also in
other animal species. The purpose of the present study was to investigate the characteristics of embryos with
MNBs (MNB embryos) that could be utilized in embryo transfer. The developmental rate of MNB embryos to the
blastocyst stage (50.8%) was significantly lower than that of normal embryos (73.3%) (P < 0.05). The
clinical pregnancy rates of fresh embryo transfer (ET) using day 2 or day 3 embryos were significantly lower
in MNB embryos (5.1%) compared with normal embryos (24.0%) (P < 0.05). In the case of frozen-thawed ET
using a single vitrified/warmed blastocyst, however, the clinical pregnancy rate of MNB embryos was close to
that of normal embryos (59.1% vs. 52.8%). Thus, the findings of the present study suggest
that the frozen-thawed ET of MNB embryos might improve the potential for implantation followed by successful
pregnancy. 相似文献
90.
Mitsuhiro IRIE Yoshinori TAKEUCHI Yuzo OHTAKE Hitomi SUZUKI Nao NAGATA Takuma MIYOSHI Yumiko KAGAWA Tetsushi YAMAGAMI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2015,77(11):1535-1539
A 13-year-old spayed mixed-breed dog was diagnosed with a gastrointestinal
stromal tumor (GIST) after histopathological examination of an abdominal mass. Five months
after surgical resection of the tumor, we detected the recurrence of GIST with multiple
disseminated abdominal lesions. A sequence analysis of cDNA obtained from a biopsy of the
recurrent tumors revealed a mutation within exon 9 of the c-kit gene
(1523A>T, Asn508Ile), which has been shown to cause ligand-independent
phosphorylation of the KIT protein in GISTs and canine mast cell tumors (MCTs). Upon
detection of the recurrent tumors, we initiated treatment with imatinib mesylate (10
mg/kg, q 24 hr). After 2 months, the dog achieved complete remission. Our findings
indicate that canine GIST, and possibly MCT, may be responsive to molecular-targeted
therapy. 相似文献