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排序方式: 共有120条查询结果,搜索用时 15 毫秒
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When animals do not become pregnant, regression of the corpus luteum (CL) is essential for normal cyclicity because it allows the development of a new ovulatory follicle. Luteal regression is caused by a pulsatile release of prostaglandin (PG) F2α from the uterus in the late luteal phase in most mammals including cattle. Although it has been proposed in ruminants that pulsatile PGF2α secretion is generated by a positive feedback loop between luteal and/or hypophyseal oxytocin and uterine PGF2α, the bovine endometrium may possess other mechanisms for initiation of luteolytic PGF2α secretion. There is increasing evidence that several cytokines mainly produced by immune cells modulate CL and uterine function in many species. Tumor necrosis factor‐α (TNF‐α) stimulates PGF2α output from bovine endometrium not only at the follicular phase but also at the late luteal phase. Administration of TNF‐α at a high concentration prolongs luteal lifespan, whereas administration of a low concentration of TNF‐α accelerates luteal regression in cows. The data obtained from the authors’ previous in vitro and in vivo studies strongly suggest that TNF‐α is a crucial factor in regulating luteolysis in cows. The authors’ recent study has shown that interleukin‐1α mediates PG secretion from bovine endometrium as a local regulator. Furthermore, interferon‐τ (IFN‐τ) suppresses the action of TNF‐α on PGF2α synthesis by the bovine endometrium in vitro, suggesting that IFN‐τ plays a luteoprotective role by inhibiting TNF‐α‐induced PGF2α production in early pregnancy. The purpose of the present review is to summarize current understanding of the endocrine mechanisms that regulate uterine function by cytokines during the estrous cycle and early pregnancy in cows. 相似文献
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Hidekatsu SHIMAKURA Tadahiro NASUKAWA Jumpei UCHIYAMA Ryosuke SUGIMOTO Ichiro IMANISHI Sumire OOTA Keijiro MIZUKAMI Masato FUJIMURA Masahiro SAKAGUCHI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(10):1509
We investigated the IgE reactivity to crude and purified milk antigens in the sera of 112 dogs with cutaneous adverse food reactions (CAFRs). Of the 112 dogs, 33 (29%) had specific IgE for crude milk antigens. In the dogs with milk-specific IgE, IgE reactivity to casein, bovine serum albumin (BSA), α-lactalbumin, β-lactoglobulin, and bovine IgG were 81%, 85%, 39%, 27%, and 35%, respectively. Casein and BSA may be important allergens in dogs with CAFRs. Some canine vaccines contain casein hydrolysate as a stabilizer and the pooled serum with anti-casein IgE showed IgE reactivity to the vaccines containing it. Information about IgE reactivity to casein in dogs with CAFRs could be useful for predicting adverse reactions to the vaccines including casein hydrolysate. 相似文献
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Dielectric properties in three main directions for hinoki wood (Chamaecyparis obtusa) specimens conditioned at various levels of relative humidity were measured in the frequency range from 20 Hz to 10 MHz over
the temperature range from −150°C to 20°C. Three relaxations were observed in the specimens conditioned at high levels of
relative humidity. The relaxation in the highest frequency range was ascribed to the motions of adsorbed water molecules.
The relaxation in the middle frequency range remained unchanged by the ethanol–benzene extraction of specimens. The relaxation
location was independent of measuring directions. The relaxation in the lowest frequency range was not detected in the specimens
impregnated with methyl methacrylate (MMA). This result suggested that the relaxation was due to electrode polarization. The
Cole-Cole circular arc law applied well to two relaxations recognized in the specimens impregnated with MMA. The relaxation
magnitude in the middle frequency range was extremely large, and the distribution of relaxation times was very narrow. These
characteristics suggested relaxation of the Maxwell-Wagner type resulting from the interfacial polarization in the heterogeneous
structure, which included adsorbed water with large electrical conductivity within the insulating cell walls. 相似文献
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Hoshi K Tanaka R Shibazaki A Nagashima Y Hirao H Namiki R Takashima K Noishiki Y Yamane Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(3):357-361
The goal of the current study was to compare the efficiency of gas exchange and platelet conservation of a new extracapillary blood flow oxygenator versus an endocapillary blood flow oxygenator during open heart surgery with extracorporeal circulation in dogs. Dilation and remodeling of the right ventricular outflow tract of dogs was performed using a patch graft technique to simulate pulmonary stenosis. Sequential pre- and post-operative blood analysis revealed that gas exchange efficiency and platelet conservation was significantly greater with the extracapillary blood flow oxygenator than with the endocapillary blood flow oxygenator. However, the priming volume of the extracapillary blood flow oxygenator was significantly greater, leading to hemodilution. We conclude that while the extracapillary blood flow oxygenator provided benefits in terms of gas exchange and platelet conservation, development of a smaller extracapillary blood flow type oxygenator to reduce hemodilution effects would be beneficial. 相似文献
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Abe S Mukai T Hirata N Barnouin-Jha OS Cheng AF Demura H Gaskell RW Hashimoto T Hiraoka K Honda T Kubota T Matsuoka M Mizuno T Nakamura R Scheeres DJ Yoshikawa M 《Science (New York, N.Y.)》2006,312(5778):1344-1347
The ranging instrument aboard the Hayabusa spacecraft measured the surface topography of asteroid 25143 Itokawa and its mass. A typical rough area is similar in roughness to debris located on the interior wall of a large crater on asteroid 433 Eros, which suggests a surface structure on Itokawa similar to crater ejecta on Eros. The mass of Itokawa was estimated as (3.58 +/- 0.18) x 10(10) kilograms, implying a bulk density of (1.95 +/- 0.14) grams per cubic centimeter for a volume of (1.84 +/- 0.09) x 10(7) cubic meters and a bulk porosity of approximately 40%, which is similar to that of angular sands, when assuming an LL (low iron chondritic) meteorite composition. Combined with surface observations, these data indicate that Itokawa is the first subkilometer-sized small asteroid showing a rubble-pile body rather than a solid monolithic asteroid. 相似文献
7.
Michiru Akamatsu Ryosuke Hirozumi Yuko Cho Yuta Kudo Keiichi Konoki Yasukatsu Oshima Mari Yotsu-Yamashita 《Marine drugs》2022,20(3)
Saxitoxin and its analogues, paralytic shellfish toxins (PSTs), are potent and specific voltage-gated sodium channel blockers. These toxins are produced by some species of freshwater cyanobacteria and marine dinoflagellates. We previously identified several biosynthetic intermediates of PSTs, as well as new analogues, from such organisms and proposed the biosynthetic and metabolic pathways of PSTs. In this study, 12β-deoxygonyautoxin 5 (12α-gonyautoxinol 5 = gonyautoxin 5-12(R)-ol) was identified in the freshwater cyanobacterium, Dolichospermum circinale (TA04), and 12β-deoxysaxitoxin (12α-saxitoxinol = saxitoxin-12(R)-ol) was identified in the same cyanobacterium and in the marine dinoflagellate Alexandrium pacificum (Group IV) (120518KureAC) for the first time from natural sources. The authentic standards of these compounds and 12α-deoxygonyautoxin 5 (12β-gonyautoxinol 5 = gonyautoxin 5-12(S)-ol) were prepared by chemical derivatization from the major PSTs, C1/C2, produced in D. circinale (TA04). These standards were used to identify the deoxy analogues by comparing the retention times and MS/MS spectra using high-resolution LC-MS/MS. Biosynthetic or metabolic pathways for these analogues have also been proposed based on their structures. The identification of these compounds supports the α-oriented stereoselective oxidation at C12 in the biosynthetic pathway towards PSTs. 相似文献
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Toshio Shibuya Shuhei Tsukuda Ayako Tokuda Shuji Shiozaki Ryosuke Endo Yoshiaki Kitaya 《Journal of Forest Research》2013,18(3):279-284
We investigated the effects of warming the basal ends of Carolina poplar (Populus × canadensis Moench.) softwood cuttings at controlled low-air-temperature on their root growth and leaf damage after planting. The warming treatment was applied to the cuttings by soaking 10 mm beyond the cut end in warmed water maintained at 30 °C in a cold chamber maintained at an air temperature of 10 °C and a photosynthetic photon flux density (PPFD) of 10 μmol m?2 s?1 (near the light compensation point at 10 °C) until rooting was observed. The warmed cuttings were then grown in a growth chamber at an air temperature of 30 °C, relative humidity 85–90 %, and a PPFD of 100 μmol m?2 s?1. Control cuttings were grown in the growth chamber throughout the experiment. Rooting occurred simultaneously for both warmed and control cuttings, irrespective of air temperature. Root development was greater and leaf damage, evaluated on the basis of extent of necrosis, was less for warmed cuttings than for control cuttings. The reduction of leaf damage for warmed cuttings probably resulted from reduced post-planting water stress and leaf senescence, because of improved root development as a result of the pre-planting warming treatment. This technique could improve the propagation of cuttings of woody plants, because it would ensure that the cuttings are ready to develop roots with minimum loss of carbohydrates, irrespective of weather conditions. 相似文献