排序方式: 共有71条查询结果,搜索用时 46 毫秒
31.
Lundgreen K Kiilerich P Tipsmark CK Madsen SS Jensen FB 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2008,178(7):909-915
Physiological mechanisms involved in acclimation to variable salinity and oxygen levels and their interaction were studied in European flounder. The fish were acclimated for 2 weeks to freshwater (1 per thousand salinity), brackish water (11 per thousand) or full strength seawater (35 per thousand) under normoxic conditions (water Po(2) = 158 mmHg) and then subjected to 48 h of continued normoxia or hypoxia at a level (Po(2) = 54 mmHg) close to but above the critical Po(2). Plasma osmolality, [Na(+)] and [Cl(-)] increased with increasing salinity, but the rises were limited, reflecting an effective extracellular osmoregulation. Muscle water content was the same at all three salinities, indicating complete cell volume regulation. Gill Na(+)/K(+)-ATPase activity did not change with salinity, but hypoxia caused a 25% decrease in branchial Na(+)/K(+)-ATPase activity at all three salinities. Furthermore, hypoxia induced a significant decrease in mRNA levels of the Na(+)/K(+)-ATPase alpha1-subunit, signifying a reduced expression of the transporter gene. The reduced ATPase activity did not influence extracellular ionic concentrations. Blood [Hb] was stable with salinity, and it was not increased by hypoxia. Instead, hypoxia decreased the erythrocytic nucleoside triphosphate content, a common mechanism for increasing blood O(2) affinity. It is concluded that moderate hypoxia induced an energy saving decrease in branchial Na(+)/K(+)-ATPase activity, which did not compromise extracellular osmoregulation. 相似文献
32.
Kyung-Chul?Choi Nelly?Auersperg Peter?CK?LeungEmail author 《Reproductive biology and endocrinology : RB&E》2003,1(1):71
Mitogen-activated protein kinases (MAPKs) are a group of serine/threonine kinases which are activated in response to a diverse
array of extracellular stimuli and mediate signal transduction from the cell surface to the nucleus. It has been demonstrated
that MAPKs are activated by external stimuli including chemotherapeutic agents, growth factors and reproductive hormones in
ovarian surface epithelial cells. Thus, the MAPK signaling pathway may play an important role in the regulation of proliferation,
survival and apoptosis in response to these external stimuli in ovarian cancer. In this article, an activation of the MAPK
signaling cascade by several key reproductive hormones and growth factors in epithelial ovarian cancer is reviewed. 相似文献
33.
It is commonly assumed that creatine kinase (CK) activity in plasma is related to the state of an inflammatory response at 24-48 h, and also it has shown biphasic patterns after a marathon run. No information is available on CK isoenzymes after an ultra-marathon run. The purpose of the present study is to examine the CK isoenzymes after a 200 km ultra-marathon run and during the subsequent recovery. Blood samples were obtained during registration 1 2 h before the 200-km race and during the race at 100 km, 150 km and at the end of 200 km, as well as after a 24 h period of recovery. Thirty-two male ultra-distance runners participated in the study. Serum CPK showed a marked increase throughout the race and 24 h recovery period (p < 0.001). Serum CK during the race occurs mostly in the CK-MM isoform and only minutely in the CK-MB isoform and is unchanged in the CK-BB isoform. High-sensitivity C-reactive protein (hs-CRP), oestradiol, AST and ALT increased significantly from the pre-race value at 100 km and a further increase took place by the end of the 200 km run. The results of our study demonstrate a different release pattern of creatine kinase after an ultra-distance (200 km) run compared to the studies of marathon running and intense eccentric exercise, and changes in several biomarkers, indicative of muscle damage during the race, were much more pronounced during the latter half (100–200 km) of the race. However, the increases in plasma concentration of muscle enzymes may reflect not only structural damage, but also their rate of clearance. 相似文献
34.
Kyung-Chul?Choi Peter?CK?Leung Eui-Bae?JeungEmail author 《Reproductive biology and endocrinology : RB&E》2005,3(1):66
Although Calbindin-D9k (CaBP-9k), a cytosolic calcium binding protein which has calcium binding sites, is expressed in various
tissues, i.e., intestine, uterus, and placenta, potential roles of this gene and its protein are not clearly understood. Uterine
CaBP-9k may be involved in controlling myometrial activity related with intracellular calcium level and is not under the control
of vitamin D despite the presence of vitamin D receptors. But, it is under the control of the sex steroid hormones, estrogen
(E2) and progesterone (P4), in female reproductive systems including the uterus and placenta. Thus, in this review, we summarize
recent research literature in regards to the expression and regulation of CaBP-9k in mammals and introduce the research data
of recent studies by us and others. 相似文献
35.
Tansley Review No. 116 总被引:3,自引:0,他引:3
36.
37.
Michael B Coulthart Gerard H Jansen Elina Olsen Deborah L Godal Tim Connolly Bernard CK Choi Zheng Wang Neil R Cashman 《BMC neurology》2011,11(1):133
Background
To better characterize the value of cerebrospinal fluid (CSF) proteins as diagnostic markers in a clinical population of subacute encephalopathy patients with relatively low prevalence of sporadic Creutzfeldt-Jakob disease (sCJD), we studied the diagnostic accuracies of several such markers (14-3-3, tau and S100B) in 1000 prospectively and sequentially recruited Canadian patients with clinically suspected sCJD. 相似文献38.
Stanley CK Cheung Li-zhong Liu Lin-lin Lan Qiao-quan Liu Samuel SM Sun Juliana CN Chan Peter CY Tong 《BMC biotechnology》2011,11(1):37
Background
Human insulin-like growth factor-I (hIGF-I) is a growth factor which is highly resemble to insulin. It is essential for cell proliferation and has been proposed for treatment of various endocrine-associated diseases including growth hormone insensitivity syndrome and diabetes mellitus. In the present study, an efficient plant expression system was developed to produce biologically active recombinant hIGF-I (rhIGF-I) in transgenic rice grains. 相似文献39.
Hyun Yang Tae-Hee Kim Hae-Hyeog Lee Kyung-Chul Choi Yeon-pyo Hong Peter CK Leung Eui-Bae Jeung 《Reproductive biology and endocrinology : RB&E》2011,9(1):28
Human endometrium resists embryo implantation except during the 'window of receptivity'. A change in endometrial gene expression
is required for the development of receptivity. Uterine calbindin-D28k (CaBP-28k) is involved in the regulation of endometrial
receptivity by intracellular Ca2+. Currently, this protein is known to be mainly expressed in brain, kidneys, and pancreas,
but potential role(s) of CaBP-28k in the human uterus during the menstrual cycle remain to be clarified. Thus, in this study
we demonstrated the expression of CaBP-28k in the human endometrium in distinct menstrual phases. During the human menstrual
cycle, uterine expression levels of CaBP-28k mRNA and protein increased in the proliferative phase and fluctuated in these
tissues, compared with that observed in other phases. We assessed the effects of two sex-steroid hormones, 17beta-estradiol
(E2) and progesterone (P4), on the expression of CaBP-28k in Ishikawa cells. A significant increase in the expression of CaBP-28k
mRNA was observed at the concentrations of E2 (10(-9 to -7) M). In addition, spatial expression of CaBP-28k protein was detected
by immunohistochemistry. CaBP-28k was abundantly localized in the cytoplasm of the luminal and glandular epithelial cells
during the proliferative phases (early-, mid-, late-) and early-secretory phase of menstrual cycle. Taken together, these
results indicate that CaBP-28k, a uterine calcium binding protein, is abundantly expressed in the human endometrium, suggesting
that uterine expression of CaBP-28k may be involved in reproductive function during the human menstrual cycle. 相似文献