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排序方式: 共有242条查询结果,搜索用时 15 毫秒
231.
O'Leary S Jasper MJ Robertson SA Armstrong DT 《Reproduction (Cambridge, England)》2006,132(1):147-158
Seminal plasma (SP) acts to influence the uterine endometrium after mating, activating synthesis of embryotrophic cytokines and inflammatory changes that condition the tract for embryo implantation and establishing pregnancy. The objective of this study was to investigate in pigs whether the ovary might also be responsive to SP exposure. Prepubertal gilts were synchronised with exogenous gonadotrophins and received transcervical treatment with pooled boar SP or PBS; then the ovarian tissue was recovered at 34 h (preovulation) and on days 5 and 9 after treatment. The ovarian response was assessed by measuring ovulation rate, number and size of corpora lutea, ovarian leukocyte populations, progesterone production in vivo, as well as responses of retrieved granulosa cells cultured in vitro. In SP-treated gilts, leukocyte recruitment into the ovarian tissues was increased fourfold at 34 h, with macrophages comprising the most abundant cell lineage. There was no effect of SP on the number of oocytes ovulated; however, the weight of corpora lutea was increased in SP-treated gilts. SP also induced an increase in plasma progesterone content seen from day 5 to at least day 9 after treatment. In addition, granulosa cells and thecal tissue retrieved from preovulatory follicles of SP-treated gilts were more responsive in vitro to growth factor- and gonadotrophin-stimulated cell proliferation and progesterone synthesis. These results suggest that uterine exposure to SP influences immune cell trafficking in the ovary and enhances steroidogenesis in early pregnancy. The effects of SP on ovarian function potentially contribute to reproductive success in the pig. 相似文献
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233.
Neutral complex-type N-glycans of the envelope glycoprotein 120 of HIV-2, propagated in different host cells, display cell-type specific variations. In order to identify typical structural elements, glycans were analysed by gel filtration, by enzymic sequencing and, in part, by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The characteristic substituents of di- tri- and tetraantennary carbohydrate units thus observed include N-acetyllactosamine repeats, bisecting N-acetylglucosamine and fucose linked to the chitobiose core as well as to N-acetyllactosamine antennae. Each glycoprotein preparation displayed a characteristic set of glycoforms. 相似文献
234.
Foraging theorists have long emphasized the role of the energy (work) costs of food items on foraging behavior. However, few experiments have measured this variable or demonstrated that animals are indeed sensitive to work costs. Experiment 1 assessed whether rats (Long-Evans) can use the work costs of food to determine whether a food patch is exhausted. Rats performed a fixed amount of work for each food item (fixed-work [FW] schedule), but food was withheld unpredictably to simulate sudden patch depletion. It was found that rats left patches only when the work costs of unsuccessful searches (giving-up work) exceeded the prevailing costs of food. The time and response costs of unsuccessful food searches (giving-up time and giving-up responses) were not predictive of patch leaving. Experiment 2 showed how rats regulated work in this paradigm by examining the exteroceptive stimuli connected with fulfilling the FW schedule. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
235.
It is known that ischemia commonly increases exogenous glucose utilization by accelerating glucose uptake and flux rates through the Embden-Meyerhof pathway. Constitutive enzymes regulate the rate of glycolysis and in turn are regulated by product inhibition and allosteric controls. The purpose of this report was to test whether mRNA abundance for select glycolytic enzymes, and glucose transport proteins, is also modified. Six intact working pig hearts with coronary flow controlled by extracorporeal perfusion were compared at the following conditions: (1) aerobic control perfusion; (2) ischemia affected by a 60% decrease in left anterior descending (LAD) coronary perfusion: (3) ischemia again affected by a 60% decrease in LAD flow followed by a 40-min interval of aerobic reflow; (4) an intermittent ischemia and reflow protocol including four cycles of similar LAD flow reductions (5 min per cycle) interspersed with 15-20 min of aerobic reperfusion; (5) a 4-day model designed to produce myocardial chronic hibernation: and (6) mild ischemia induced by a 40% decrease in LAD flow for 85 min to produce certain adaptations compatible with short-term hibernation. In each heart, mRNA abundance was measured from LAD and circumflex (LCF) perfused myocardium for hexokinase, phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase and the two glucose transporter isomers, GLUT 4 and GLUT 1. mRNA data from LAD myocardium in intervention hearts were normalized to those from LAD tissue in the control heart (LADc) and with LCF values in the same intervention hearts. Signal variance around unity in the LAD tissue, with respect to that of the LCF myocardium, in the control heart compared closely (44 and 41% in two separate runs, respectively). GLUT 1/GLUT 4 ratios in the LAD and LCF beds of this heart also agreed closely. LAD/LADc ratios were increased for hexokinase (1.69), phosphofructokinase (3.69), and glyceraldehyde-3-phosphate dehydrogenase (2.29) in the ischemia heart and for phosphofructokinase (3.90), glyceraldehyde-3-phosphate dehydrogenase (2.20), GLUT 4 (1.55) and GLUT 1 (2.20) in the ischemia/reflow heart. There was no evidence of excess signal in the intermittent ischemia/reflow, chronic hibernation, or mild ischemia hearts. Altered signal from LCF myocardium was also suggested. These data indicate that mRNA abundance for select glycolytic enzymes and transporter proteins is increased in ischemic myocardium with or without reperfusion and offers a possible mechanism for increased protein activity in settings of diminished regional coronary flow. 相似文献
236.
Maik Liedtke Christin Vlkner Alexandra V. Jürs Franziska Peter Michael Rabenstein Andreas Hermann Moritz J. Frech 《International journal of molecular sciences》2021,22(8)
Niemann-Pick type C2 (NP-C2) disease is a rare hereditary disease caused by mutations in the NPC2 gene. NPC2 is a small, soluble protein consisting of 151 amino acids, primarily expressed in late endosomes and lysosomes (LE/LY). Together with NPC1, a transmembrane protein found in these organelles, NPC2 accomplishes the exclusion of cholesterol; thus, both proteins are essential to maintain cellular cholesterol homeostasis. Consequently, mutations in the NPC2 or NPC1 gene result in pathophysiological accumulation of cholesterol and sphingolipids in LE/LY. The vast majority of Niemann-Pick type C disease patients, 95%, suffer from a mutation of NPC1, and only 5% display a mutation of NPC2. The biochemical phenotype of NP-C1 and NP-C2 appears to be indistinguishable, and both diseases share several commonalities in the clinical manifestation. Studies of the pathological mechanisms underlying NP-C2 are mostly based on NP-C2 animal models and NP-C2 patient-derived fibroblasts. Recently, we established induced pluripotent stem cells (iPSCs), derived from a donor carrying the NPC2 mutations c.58G>T/c.140G>T. Here, we present a profile of pathophysiological in vitro features, shared by NP-C1 and NP-C2, of neural differentiated cells obtained from the patient specific iPSCs. Profiling comprised a determination of the NPC2 protein level, detection of cholesterol accumulation by filipin staining, analysis of oxidative stress, and determination of autophagy. As expected, the NPC2-deficient cells displayed a significantly reduced amount of NPC2 protein, and, accordingly, we observed a significantly increased amount of cholesterol. Most notably, NPC2-deficient cells displayed only a slight increase of reactive oxygen species (ROS), suggesting that they do not suffer from oxidative stress and express catalase at a high level. As a site note, comparable NPC1-deficient cells suffer from a lack of catalase and display an increased level of ROS. In summary, this cell line provides a valuable tool to gain deeper understanding, not only of the pathogenic mechanism of NP-C2, but also of NP-C1. 相似文献
237.
Caterpillar‐Inspired Design and Fabrication of A Self‐Walking Actuator with Anisotropy,Gradient, and Instant Response 下载免费PDF全文
Bin Li Tao Du Bo Yu Jasper van der Gucht Feng Zhou 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(28):3494-3501
A caterpillar–mimetic bilayer actuator is reported, based on a wrinkled polydimethylsiloxane elastomer decorated with a hydroresponsive polyelectrolyte brush. The actuator can fold ultrafast into complex three‐dimensional structures upon a change in relative humidity of the surrounding air. The folding direction is determined by the geometry of the actuator, the orientation of the wrinkles, and the gradient in polymer height on the surface. And some unique structures such as helicoid and gradient can be obtained that are seldom reported in the case of bilayered devices. The adaptive bending movement is very fast, anisotropic, highly efficient, and reversible. When the environmental humidity is repeatedly cycled up and down, the small device walks on a surface with a roughness gradient, which is reminiscent of the muscle‐like movements. 相似文献
238.
239.
Luisa Jasper Pasquale Scarcia Stephan Rust Janine Reunert Ferdinando Palmieri Thorsten Marquardt 《International journal of molecular sciences》2021,22(18)
SLC25A36 is a pyrimidine nucleotide carrier playing an important role in maintaining mitochondrial biogenesis. Deficiencies in SLC25A36 in mouse embryonic stem cells have been associated with mtDNA depletion as well as mitochondrial dysfunction. In human beings, diseases triggered by SLC25A36 mutations have not been described yet. We report the first known case of SLC25A36 deficiency in a 12-year-old patient with hypothyroidism, hyperinsulinism, hyperammonemia, chronical obstipation, short stature, along with language and general developmental delay. Whole exome analysis identified the homozygous mutation c.803dupT, p.Ser269llefs*35 in the SLC25A36 gene. Functional analysis of mutant SLC25A36 protein in proteoliposomes showed a virtually abolished transport activity. Immunoblotting results suggest that the mutant SLC25A36 protein in the patient undergoes fast degradation. Supplementation with oral uridine led to an improvement of thyroid function and obstipation, increase of growth and developmental progress. Our findings suggest an important role of SLC25A36 in hormonal regulations and oral uridine as a safe and effective treatment. 相似文献
240.
Jasper Killat Kerstin Reimers Claudia Y. Choi Sabrina Jahn Peter M. Vogt Christine Radtke 《International journal of molecular sciences》2013,14(7):14460-14474
New skin substitutes for burn medicine or reconstructive surgery pose an important issue in plastic surgery. Matriderm® is a clinically approved three-dimensional bovine collagen-elastin matrix which is already used as a dermal substitute of full thickness burn wounds. The drawback of an avital matrix is the limited integration in full thickness skin defects, depending on the defect size. To further optimize this process, Matriderm® has also been studied as a matrix for tissue engineering of skin albeit long-term cultivation of the matrix with cells has been difficult. Cells have generally been seeded onto the matrix with high cell loss and minimal time-consuming migration. Here we developed a cell seeded skin equivalent after microtransfer of cells directly into the matrix. First, cells were cultured, and microinjected into Matriderm®. Then, cell viability in the matrix was determined by histology in vitro. As a next step, the skin substitute was applied in vivo into a full thickness rodent wound model. The wound coverage and healing was observed over a period of two weeks followed by histological examination assessing cell viability, proliferation and integration into the host. Viable and proliferating cells could be found throughout the entire matrix. The presented skin substitute resembles healthy skin in morphology and integrity. Based on this study, future investigations are planned to examine behaviour of epidermal stem cells injected into a collagen-elastin matrix under the aspects of establishment of stem cell niches and differentiation. 相似文献