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1.
Statistical averages and correlations for backbone torsion angles of chymotrypsin inhibitor 2 are calculated by using the Rotational Isomeric States model of chain statistics. Statistical weights of torsional states of phipsi pairs, needed for the statistics of the full chain, are obtained in two different ways: 1) by using knowledge-based pairwise dependent phipsi energy maps from Protein Data Bank (PDB) and 2) by collecting torsion angle data from a large number of random coil configurations of an all-atom protein model with volume exclusion. Results obtained by using PDB data show strong correlations between adjacent torsion angle pairs belonging to both the same and different residues. These correlations favor the choice of the native-state torsion angles, and they are strongly context dependent, determined by the specific amino acid sequence of the protein. Excluded volume or steric clashes, only, do not introduce context-dependent phipsi correlations into the chain that would affect the choice of native-state torsional angles. 相似文献
2.
Celik-Ozenci C Akkoyunlu G Korgun ET Savas B Demir R 《Molecular reproduction and development》2004,67(4):414-423
It is accepted that angiogenesis plays an important role in the development of the corpus luteum (CL) and is probably necessary for normal lutein cell function. A number of drugs currently being tested in clinical trials as possible angiogenesis inhibitors were not originally developed with the intention of suppressing tumor angiogenesis. Interferon alpha (IFN-alpha) is one of the notable examples of such 'accidental angiogenesis inhibitors' and daily administration of IFN-alpha is known to suppress tumor growth, tumor vascularization, and down-regulation of various growth factors. We investigated the effects of IFN-alpha treatment on the expression of vascular endothelial growth factor (VEGF), and its receptors KDR and Flt-1, and CD34 in CL during the first week of pseudopregnancy and pregnancy in hormonally induced rat ovaries by immunohistochemistry and Western blot techniques. Basal body temperatures of the drug-treated rats, as an indicator of treatment effect, were determined daily and were increased significantly when compared to controls (38.03 +/- 0.18 vs. 36.6 +/- 0.1 degrees C), respectively. The effect of IFN-alpha treatment was minimal when the entire week was evaluated, however, the expression of VEGF decreased at 3rd, 5th, and 7th days of both pregnancy and pseudopregnancy, when compared to the 1st day, whereas there was not a such alteration in the untreated rats regarding these days. The daily subcutaneous administrations of 672.500 U IFN-alpha2b had minimal effects on the expressions of VEGF, and its two receptors KDR and Flt-1 in either pregnant or pseudopregnant corpora lutea utilizing HSCORE. 相似文献
3.
The placenta is a complicated tissue that lies between maternal and fetal compartments. Although the architecture of the human
and rodent placentas differ a little in their details, their overall structures and the molecular mechanisms of placental
developments are thought to be very similar. In rats, fetal–placental exposure to maternally administered glucocorticoids
decreases birth weight and placental weight. The mechanism underlying the placental growth inhibitory effects of glucocorticoids
have not been elucidated. Moreover it is still not determined that how Akt and ERK1/2 proteins related proliferation and apoptosis
mechanisms are influenced by dexamethasone-induced IUGR (Intrauterine Growth Restriction) placentas. The aim of this study
was to investigate the expression levels and spatio-temporal immunolocalizations of Akt, p-Akt, ERK1/2 and p-ERK1/2 proteins
in normal and dexamethasone treated placental development in pregnant Wistar rats. Pregnant rats were subcutaneously injected
with 100 μg/kg dexamethasone 21-acetate in 0.1 ml 10% ethanol on day 10 and 12 of gestation. Afterwards injection was continued
as 200 μg/kg until they were killed on day 12 (injection started on day 10), 14, 16, 18 and 20 (injections started on day
12) of pregnancy. Placental and embryonal tissues were collected for immunohistochemistry and Western blot analysis. We found
that maternal dexamethasone treatment led to a decrease in ERK1/2 and Akt activation during rat placental development. The
decrease in Akt and ERK1/2 activations may result with cell survival inhibition or apoptosis stimulation. Hence, dexamethasone
induced placental and embryonal developmental abnormalities could be associated with reduction of Akt and ERK1/2 activation. 相似文献
4.
Yilmaz N Karaali K Ozdem S Turkay M Unal A Dora B 《Cellular and molecular neurobiology》2011,31(4):579-585
Although migraine has mainly been considered as a benign disease, there is cumulative evidence of silent changes in the brain,
brainstem, or cerebellum and subtle subclinical cerebellar dysfunction. In this study, in order to investigate a possible
neuronal and/or glial damage at the cellular level in migraine, we measured and compared serum levels of S100B which is a
protein marker of glial damage or activation, and neuron specific enolase (NSE) which is a marker of neuronal damage, in migraine
patients and control subjects. Serum levels of S100B and NSE were measured in blood samples from 41 patients with migraine-without
aura taken during a migraine attack (ictal) and in the attack-free period between migraine attacks (interictal) and 35 age-
and sex-matched controls. Patients with migraine-without aura had significantly higher ictal serum levels of S100B and NSE
(P < 0.05, for both) than control subjects; whereas in the interictal phase, there was a significant increment only in S100B
levels (P < 0.05) compared to controls. On the other hand, serum levels of S100B and NSE in ictal and interictal blood samples did
not differ significantly. The findings of increased ictal serum S100B and NSE levels together with increased interictal levels
of S100B suggested that migraine might be associated with glial and/or neuronal damage in the brain and a prolonged disruption
of blood–brain barrier. Increased interictal serum levels of S100B might point out to an insidious and slow damaging process
in migraine patients. 相似文献
5.
Ozcan A Deveci MS Oztas E Dede M Yenen MC Korgun ET Gunhan O 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》2005,27(4):181-186
OBJECTIVE: To investigate the reported increase in the expression of the glucose transporter GLUT-1 in borderline and malignant ovarian epithelial tumors and its relationship to prognosis. STUDY DESIGN: In this study, areas in which immunohistochemical membranous staining with GLUT-1 were most evident were selected, and the proportions of GLUT-1 expression in 46 benign, 11 borderline and 42 malignant cases of ovarian epithelial tumors were determined quantitatively with a computer and Zeiss Vision KS 400 3.0 (G?ttingen, Germany) for Windows (Microsoft, Redmond, Washington, U.S.A.) image analysis. RESULTS: GLUT-1 expression was determined in all borderline tumors (11 of 11) and in 97.6% of malignant tumors (41 of 42). No GLUT-1 expression was observed in benign tumors. The intensity of GLUT-1 staining was lower in borderline tumors than in malignant cases. This was statistically significant (p = 0.005). As differentiation in malignant tumors increased, proportions of GLUT-1 expression showed a relative increase, but this difference was not statistically significant (p = 0.68). CONCLUSION: When GLUT-1 expression in borderline and malignant ovarian epithelial tumors was analyzed against prognosis, no statistically significant difference was identified. Assessment of GLUT-1 expression using the image analysis program was more reliable, with higher reproducibility than in previous studies. 相似文献
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7.
Background
An important use of data obtained from microarray measurements is the classification of tumor types with respect to genes that are either up or down regulated in specific cancer types. A number of algorithms have been proposed to obtain such classifications. These algorithms usually require parameter optimization to obtain accurate results depending on the type of data. Additionally, it is highly critical to find an optimal set of markers among those up or down regulated genes that can be clinically utilized to build assays for the diagnosis or to follow progression of specific cancer types. In this paper, we employ a mixed integer programming based classification algorithm named hyper-box enclosure method (HBE) for the classification of some cancer types with a minimal set of predictor genes. This optimization based method which is a user friendly and efficient classifier may allow the clinicians to diagnose and follow progression of certain cancer types.Methodology/Principal Findings
We apply HBE algorithm to some well known data sets such as leukemia, prostate cancer, diffuse large B-cell lymphoma (DLBCL), small round blue cell tumors (SRBCT) to find some predictor genes that can be utilized for diagnosis and prognosis in a robust manner with a high accuracy. Our approach does not require any modification or parameter optimization for each data set. Additionally, information gain attribute evaluator, relief attribute evaluator and correlation-based feature selection methods are employed for the gene selection. The results are compared with those from other studies and biological roles of selected genes in corresponding cancer type are described.Conclusions/Significance
The performance of our algorithm overall was better than the other algorithms reported in the literature and classifiers found in WEKA data-mining package. Since it does not require a parameter optimization and it performs consistently very high prediction rate on different type of data sets, HBE method is an effective and consistent tool for cancer type prediction with a small number of gene markers. 相似文献8.
Conserved residues in protein-protein interfaces correlate with residue hot-spots. To obtain insight into their roles, we have studied their mobility. We have performed 39 explicit solvent simulations of 15 complexes and their monomers, with the interfaces varying in size, shape, and function. The dynamic behavior of conserved residues in unbound monomers illustrates significantly lower flexibility as compared to their environment, suggesting that already before binding they are constrained in a boundlike configuration. To understand this behavior, we have analyzed the inter- and intrachain hydrogen-bond residence-time in the interfaces. We find that conserved residues are not involved significantly in hydrogen bonds across the interface as compared to nonconserved. However, the monomer simulations reveal that conserved residues contribute dominantly to hydrogen-bond formation before binding. Packing of conserved residues across the trajectories is significantly higher before and after the binding, rationalizing their lower mobility. Backbone torsional angle distributions show that conserved residues assume restricted regions of space and the most visited conformations in the bound and unbound trajectories are similar, suggesting that conserved residues are preorganized. Combined with previous studies, we conclude that conserved residues, hot spots, anchor, and interface-buried residues may be similar residues, fulfilling similar roles. 相似文献
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10.
Do glucose transporters have other roles in addition to placental glucose transport during early pregnancy? 总被引:3,自引:1,他引:2
Korgun ET Celik-Ozenci C Seval Y Desoye G Demir R 《Histochemistry and cell biology》2005,123(6):621-629
Human placenta regulates the transport of maternal molecules to the fetus. It is known that glucose transport occurs via glucose transporters (GLUTs) in the feto–placental unit. Data on the expression of GLUTs during implantation are very scarce. Moreover, the question of how the decidual leukocytes obtain the energy for their activation during implantation mechanism is still under investigation. We studied the distributions of GLUT1, GLUT3, and GLUT4 in tissue sections of first trimester pregnancies the human maternal–fetal interface. GLUT1 was present in apical microvilli of the syncytiotrophoblast, in cytotrophoblast, and in vascular patterns of the villous core, whereas GLUT3 was localized in cytotrophoblasts of placental villi and in some fetal endothelial cells. Moreover, the proliferating cells of the proximal cell columns were also immunopositive for GLUT1 and GLUT3. We did not observe any positive immunoreactivity for GLUT4 in placental and decidual tissues. Essentially, GLUT3 and also to some extent GLUT1 was present in maternal leukocytes and platelets. In conclusion, our results suggest that the glucose taken up via GLUT1 and GLUT3 from the maternal circulation might not only be needed for placental functions but also for successful implantation by trophoblast invasion, proliferation and also by having a role to support energy for maternal leukocytes. 相似文献