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排序方式: 共有113条查询结果,搜索用时 15 毫秒
31.
The bulbus arteriosus of stenothermal and temperate teleosts: a morphological approach 总被引:1,自引:0,他引:1
The bulbus arteriosus, 'windkessel', of several species of stenothermal and temperate teleosts has been studied by conventional light microscopy and electron microscopy. The bulbus wall is divided into an endocardium, ridges, and middle and external layers. The endocardium of all species shows moderately-dense bodies, which vary widely although the significance is not known. The endocardium in Antarctic teleosts invaginates into the ridge tissue to form solid epithelial cords that show signs of active secretion related to protective substances. Cords also form in serranidic and sparidic species, but signs of active secretion are not evident. The ridges consist of cells within a filamentous meshwork. Ridge cells appear to be smooth muscle cells that undergo a phenotypic transition from the endocardium toward the middle layer. Middle layer cells are typical smooth muscle cells surrounded by a filamentous matrix. The appearance and composition of the extracellular matrix varies widely among species, with those from the Antarctic lacking collagen and elastin fibres. The external layer is a collagenous matrix that contains fibroblasts, blood vessels and nerves. In most Antarctic teleost species this layer lacks blood vessels, but contains nerve fibres. Some of these fibres could have a sensory function to control bulbus dilatation. The external layer of Trematomus bernacchii has the appearance of a germinal centre and may be involved in the immune humoral response. The epicardium is atight epithelium that may control passage of substances with the pericardial cavity. 相似文献
32.
The antagonist carazolol has been used as a fluorescent probe for the binding site of the beta-adrenergic receptor (beta AR). The fluorescence properties of carazolol are dominated by the emission of the carbazole group, with the fine structure of the spectrum, but not the quantum yield, sensitive to the environment of the probe. The fluorescence emission spectrum of the bound probe is consistent with an extremely hydrophobic environment in the binding site of the receptor. Binding of carazolol to the purified beta AR increases the polarization of the fluorophore. Exposure to collisional quenchers has demonstrated the bound carazolol to be completely inaccessible to the solvent. Furthermore, the fluorescence of bound carazolol is not quenched by exposure to sodium nitrite, a F?rster energy acceptor which has an R0 value of 11.7 A with carazolol. Thus, physical analysis of the binding site of the beta AR by carazolol fluorescence indicates that the antagonist binds to the beta AR in a rigid hydrophobic environment which is buried deep within the core of the protein. 相似文献
33.
Rohit P. Ojha Joseph E. Tota Tabatha N. Offutt-Powell James L. Klosky Timothy D. Minniear Bradford E. Jackson James G. Gurney 《PloS one》2013,8(8)
Long-term survivors of pediatric and young adult (PAYA) cancers have a high incidence of subsequent neoplasms, but few risk factors other than cancer treatment have been identified. We aimed to describe the burden of human papillomavirus (HPV)-associated malignancies among survivors of PAYA cancers to assess whether HPV infections might be a reasonable area of future etiologic research on subsequent malignancies in this population. We used longitudinal data from 9 population-based registries of the Surveillance, Epidemiology, and End Results program collected between 1973 and 2010 to assemble a cohort of individuals who were diagnosed with any cancer between the ages of 0 and 29 years and survived at least 5 years post-diagnosis. We estimated sex-specific standardized incidence ratios (SIRs) with corresponding 95% confidence limits (CL) of HPV-associated subsequent malignancies (cervical, vaginal, vulvar, penile, anal, tongue, tonsillar, and oropharyngeal). Our study population comprised 64,547 long-term survivors of PAYA cancers diagnosed between 1973 and 2010. Compared with females in the general US population, female PAYA cancer survivors had a 40% relative excess of HPV-associated malignancies overall (SIR = 1.4, 95% CL: 1.2, 1.8). Compared with males in the general US population, male PAYA cancer survivors had a 150% relative excess of HPV-associated malignancies overall (SIR = 2.5, 95% CL: 1.9, 3.4). Our findings suggest an excess of HPV-associated malignancies among PAYA cancer survivors compared with the general US population. We hypothesize that a portion of subsequent malignancies among PAYA cancer survivors may be directly attributable to HPV infection. This hypothesis warrants exploration in future studies. 相似文献
34.
Anna Maria Quintieri Noemi Baldino Elisabetta Filice Lucia Seta Antonio Vitetti Bruno Tota Bruno De Cindio Maria Carmela Cerra Tommaso Angelone 《The Journal of nutritional biochemistry》2013,24(7):1221-1231
A moderate red wine consumption and a colored fruit-rich diet protect the cardiovascular system, thanks to the presence of several polyphenols. Malvidin-3-0-glucoside (malvidin), an anthocyanidine belonging to polyphenols, is highly present in red grape skin and red wine. Its biological activity is poorly characterized, although a role in tumor cell inhibition has been found. To analyze whether and to which extent, like other food-derived polyphenols, malvidin affects the cardiovascular function, in this study, we have performed a quantitative analysis by high-performance liquid chromatography of polyphenolic content of red grape skins extract, showing that it contains a high malvidin amount (63.93±12.50 mg/g of fresh grape skin). By using the isolated and Langendorff perfused rat heart, we found that the increasing doses (1–1000 ng/ml) of the extract induced positive inotropic and negative lusitropic effects associated with coronary dilation. On the same cardiac preparations, we observed that malvidin (10?10–10?6 mol/L) elicited negative inotropism and lusitropism and coronary dilation. Analysis of mechanism of action revealed that malvidin-dependent cardiac effects require the activation of the phosphatidylinositol 3-kinase (PI3K)/nitric oxide (NO)/cGMP/PKG pathway and are associated with increased intracellular cGMP and the phosphorylation of endothelial NO synthase (eNOS), PI3K–AKT, ERK1/2, and GSK-3β. AKT and eNOS phosphorylation was confirmed in human umbilical vein endothelial cell. We also found that malvidin act as a postconditioning agent, being able to elicit cardioprotection against ischemia/reperfusion damages. Our results show the cardioactivity of polyphenols-rich red grape extracts and indicate malvidin as a new cardioprotective principle. This is of relevance not only for a better clarification of the beneficial cardiovascular effects of food-derived polyphenols but also for nutraceutical research. 相似文献
35.
Marin Tota Hrvoje Jakovac Damir Grebić Jelena Marinić Dalibor Broznić Gordana Čanadi-Jurešić Čedomila Milin Biserka Radošević-Stašić 《Biological trace element research》2011,143(1):332-343
To elucidate the role of iron in the pathomechanisms of autoimmune CNS disorders, we estimated the tissue concentrations of
Fe2+ in the brain, spinal cord, and liver in the chronic relapsing form of experimental autoimmune encephalomyelitis (EAE). The
disease was induced in Dark Agouti (DA) strain of rats, by subcutaneous injection of bovine brain homogenate in complete Freund's
adjuvant (CFA). Control rats consisted of unsensitized rats and of rats treated with CFA or saline. The data obtained by clinical
assessment and by inductively coupled plasma spectrometry have shown that the attacks of disease (on the 12th and 22nd post-immunization
day) were followed by high accumulation of iron in the liver. Additionally, during the second attack of disease, the decreased
concentration of Fe2+ was found in cervical spinal cord. The data point to regulatory effects of iron and hepatic trace elements regulating mechanisms
in the pathogenesis of EAE. 相似文献
36.
Shen DM Brady EJ Candelore MR Dallas-Yang Q Ding VD Feeney WP Jiang G McCann ME Mock S Qureshi SA Saperstein R Shen X Tong X Tota LM Wright MJ Yang X Zheng S Chapman KT Zhang BB Tata JR Parmee ER 《Bioorganic & medicinal chemistry letters》2011,21(1):76-81
A novel class of 1,3,5-pyrazoles has been discovered as potent human glucagon receptor antagonists. Notably, compound 26 is orally bioavailable in several preclinical species and shows selectivity towards cardiac ion channels, other family B receptors such hGIP and hGLP1, and a large panel of enzymes and additional receptors. When dosed orally, compound 26 is efficacious in suppressing glucagon induced plasma glucose excursion in rhesus monkey and transgenic murine pharmacodynamic models at 1 and 10 mpk, respectively. 相似文献
37.
Liang R Abrardo L Brady EJ Candelore MR Ding V Saperstein R Tota LM Wright M Mock S Tamvakopolous C Tong S Zheng S Zhang BB Tata JR Parmee ER 《Bioorganic & medicinal chemistry letters》2007,17(3):587-592
A series of conformationally constrained tri-substituted ureas were synthesized, and their potential as glucagon receptor antagonists was evaluated. This effort resulted in the identification of compound 4a, which had a binding IC50 of 4.0 nM and was shown to reduce blood glucose levels at 3 mg/kg in glucagon-challenged mice containing a humanized glucagon receptor. Compound 4a was efficacious in correcting hyperglycemia induced by a high fat diet in transgenic mice at an oral dose as low as 3 mg/kg. 相似文献
38.
Jakovac H Grebić D Mrakovcić-Sutić I Tota M Broznić D Marinić J Tomac J Milin C Radosević-Stasić B 《Biological trace element research》2006,114(1-3):249-268
To better elucidate previous results showing that partial hepatectomy noticeably changes the tissue content of zinc, calcium,
magnesium, and iron(II) ions in regenerating the liver, thymus, and spleen, we report on the correlation of these metal tissue
kinetics in these organs with the expression of metallothionein-I+II (MT-I+II) proteins and MT-I mRNA in early postoperative
period (1, 2, 6, 12, and 24 h) after one-third hepatectomy (pHx). The results showed that 2 h after pHx the regenerating liver
accumulated Zn2+, Ca2+, Mg2+, and Fe2+ ions while decreasing the concentration of all these metals in the spleen and of Zn2+ in the thymus. On the 24th h, a new high accumulation of Zn2+ and Ca2+ was seen in the regenerating liver and of Zn2+, Ca2+, and Fe2+ in the spleen. Simultaneously, MT-I mRNA increased in the liver and spleen. In hepatocytes and on several spleen and thymus
mononuclear lymphatic cells, the increased expression of MT proteins was found mainly in the cytoplasm and nuclei. The areas
expressing MTs in regenerating liver inversely correlated with those containing apoptotic cells, suggesting that these proteins
participate in tissue restoration through reduction or increase of metal ions after injury to the liver. 相似文献
39.
AngⅡ诱导的VEGF对食用蛙心包淋巴孔和间皮血窦的影响 总被引:3,自引:0,他引:3
血紧张素Ⅱ(angiotensin Ⅱ,AngⅡ)在许多血管性疾病中发挥了重要作用。本文研究AngⅡ对血管内皮细胞生长因子(vascular endothelial growth factor,VEGF)调控蛙心包淋巴孔和心包间皮血窦的影响,选用食用蛙(Rana esculenta)进行本项目研究,应用AngⅡ+VEGF和VEGF蛙腹膜腔注射,扫描电镜观察和计算机图像处理。正常蛙心包壁层有一些散在分布的心包淋巴孔和少量间皮血窦。VEGF组的淋巴孔直径、分布密度和间皮血窦面积分别是1.50μm、8.25/0.1mm^2和2443.95μm^2/0.1mm^2均高于对照组(P<0.01)。AngⅡ对VEGF有明显诱导作用,使淋巴孔直径(2.81μm)、分布密度(2882/0.1mm^2)和血窦面积(3866.15μm^2/0.1mm^2)高于VEGF组,两者有显著差异(P<0.05)。VEGF可使蛙心包淋巴孔开放数量增多,孔径开大,分布密度增高,具有明显调控心包淋巴孔的功能;此外,还能使心包间皮血窦面积增多,进而使心包间皮通透性增加。AngⅡ能促进VEGF的作用,这对于加速心包腔内物质转归,促进心包膜漏出,防止心肌间质水肿有重要作用。结果提示,AngⅡ对VEGF的诱导作用可能是通过增加VEGF基因的表达而实现。 相似文献
40.
Čedomila Milin Robert Domitrović Marin Tota Jasminka Giacometti Mira Ćuk Biserka Radošević-Stašić Zlatko Ciganj 《Biological trace element research》2001,82(1-3):201-210
The mineral content (zinc, iron, magnesium, and calcium) in the liver, spleen, and thymus of male Balb/C mice was analyzed.
Animals were fed, over 21 d, diets enriched with corn oil (FCO diet) or olive oil (FOO diet) (5% addition to standard pellet,
w/w). Olive oil with predominant oleic acid (C18:1, n-9) had a quite different composition than corn oil, in which linoleic
acid (C18:2, n-6) prevails. The zinc and magnesium tissue concentrations were not changed in either group. The calcium concentration
in liver as well as the calcium concentration in spleen increased in mice fed both the FCO and FOO diets. Furthermore, mice
fed both the FOO and FCO diets had increased spleen iron concentration. Mice fed the FCO diet had increased thymus calcium
concentration compared to controls. The results show the effect of diets with unsaturated, particularly polyunsaturated fatty
acids, on the calcium and iron concentration in some organs. 相似文献