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排序方式: 共有340条查询结果,搜索用时 15 毫秒
1.
María De Los Ángeles Monclus Andreína Cesari María Eugenia Cabrillana Paola Vanina Borelli Amanda Edith Vincenti Mario Héctor Burgos Miguel Walter Fornés 《Anatomical record (Hoboken, N.J. : 2007)》2007,290(7):814-824
In many mammals, sperm associations had been observed, but not in the mouse. In this work, mouse sperm rosettes are morphologically described inside the epididymis and during its dissolution in a culture medium. Also characterized are the saccharides present in the linking material. Sperm association and other epididymal actions are supported by sperm during epididymal transit and are verified at the caudal region, suggesting a relation between epididymal transit and sperm maturation. In drops of epididymal content obtained from distal (cauda), but not from proximal (caput and corpus) regions; dissolved in culture medium, rosettes appear to be 10 to 15 motile sperm joined by their heads. After 3 min, sperm progressively detach, disassembling the rosette. These structures are studied by several techniques, including optic, electronic (scanning electron microscopy and transmission electron microscopy), and video microscopy. At the ultrastructural level, a dense network of electron‐dense material was observed between sperm heads, joining them. Based on previous works in rat, several lectins were used to characterize the type of saccharides present in this linking material. To avoid the contact between sperm and epididymal fluid from distal region—that probably exerts an influence on sperm association—a ligature was placed between caput and corpus. This epididymal content isolated from caput did not display any rosettes after 28 days. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc. 相似文献
2.
Theoretical substantiation and practical experience of vibromechanical dilatation of a tubular organ
S. A. Regirer N. A. Chigogidze L. B. Vanina K. G. Vasil'ev S. S. Mikhailov 《Biomedical engineering》1998,32(1):29-34
Conclusions
Bakulev Research Center for Cardiovascular Surgery, Russian Academy of Medical Sciences, Moscow. Institute of Mechanics, Moscow
State University. Translated from Meditsinskaya Tekhnika, No. 1, pp. 27–32, January–February, 1998. 相似文献
1. | Force applied to the tubular organ walls in the place of contact with the flexible rotating shaft of the dilatation catheter is normal to the wall surface and does not exceed physiological value (except for very stiff walls). |
2. | Power consumption measurement allows estimation of only tangential forces. |
3. | Vibromechanical dilatation is a promising technique for treating stenoses of tubular organs. |
3.
Mast cells express a peripheral cannabinoid receptor with differential sensitivity to anandamide and palmitoylethanolamide. 总被引:21,自引:1,他引:20 下载免费PDF全文
L Facci R Dal Toso S Romanello A Buriani S D Skaper A Leon 《Proceedings of the National Academy of Sciences of the United States of America》1995,92(8):3376-3380
Mast cells are multifunctional bone marrow-derived cells found in mucosal and connective tissues and in the nervous system, where they play important roles in tissue inflammation and in neuroimmune interactions. Very little is known about endogenous molecules and mechanisms capable of modulating mast cell activation. Palmitoylethanolamide, found in peripheral tissues, has been proposed to behave as a local autacoid capable of downregulating mast cell activation and inflammation. A cognate N-acylamide, anandamide, the ethanolamide of arachidonic acid, occurs in brain and is a candidate endogenous agonist for the central cannabinoid receptor (CB1). As a second cannabinoid receptor (CB2) has been found in peripheral tissues, the possible presence of CB2 receptors on mast cells and their interaction with N-acylamides was investigated. Here we report that mast cells express both the gene and a functional CB2 receptor protein with negative regulatory effects on mast cell activation. Although both palmitoylethanolamide and anandamide bind to the CB2 receptor, only the former downmodulates mast cell activation in vitro. Further, the functional effect of palmitoylethanolamide, as well as that of the active cannabinoids, was efficiently antagonized by anandamide. The results suggest that (i) peripheral cannabinoid CB2 receptors control, upon agonist binding, mast cell activation and therefore inflammation; (ii) palmitoylethanolamide, unlike anandamide, behaves as an endogenous agonist for the CB2 receptor on mast cells; (iii) modulatory activities on mast cells exerted by the naturally occurring molecule strengthen a proposed autacoid local inflammation antagonism (ALIA) mechanism; and (iv) palmitoylethanolamide and its derivatives may provide antiinflammatory therapeutic strategies specifically targeted to mast cells ("ALIAmides"). 相似文献
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Maria Luisa Torre Giuseppina T. Russo Marta Ragonese Annalisa Giandalia Ernesto De Menis Giorgio Arnaldi Angela Alibrandi Carmelo Buda Giovanni Romanello Elisabetta L. Romeo Domenico Cucinotta Francesco Trimarchi Salvatore Cannavo 《Pituitary》2014,17(3):257-266
Background
Acromegalic patients have a higher risk of developing colorectal tumours (CRT). The common C677T polymorphism in methylenetetrahydrofolate reductase (MTHFR) gene is a well-documented CRT risk factor in the general population, but its role in acromegaly has never been examined.Purpose
We investigated the influence of MTHFR C677T polymorphism, folate status and other lifestyle, nutritional and disease-specific variables on CRT risk in acromegaly.Methods
Clinical data were collected from 115 acromegalic patients (25 with active disease) who underwent a complete colonoscopy. C677T MTHFR genotype, homocysteine, vitamin B12, insulin growth factor and insulin levels, as well as metabolic variables were evaluated.Results
Colorectal tumours were identified in 51 patients (3 adenocarcinomas). MTHFR C677T distribution was in the Hardy–Weinberg equilibrium and similar in patients with or without CRT. There was a correlation between patients with TT genotype and CRT occurrence (Spearman’s test: P = 0.03), with an Odds Ratio (OR) of 1.32 (95 % CI 0.522–3.362, P NS). A folate–MTHFR genotype interaction on CRT risk was found (P = 0.037): in the lower folate subgroup, TT patients showed a 2.4 higher OR for CRT (95 % CI 0.484–11.891; P NS) than C-allele carriers. Smoking (P = 0.007), increased HbA1c levels (P = 0.021), dyslipidaemia (P = 0.049), acromegaly control (P = 0.057), and folate–MTHFR genotype interaction (P = 0.088) were associated with CRT at multivariate analysis.Conclusions
In this cohort of acromegalic patients, CRT risk is increased in 677TT MTHFR patients with low plasma folate levels. Smoking, high HbA1c levels, dyslipidaemia and disease activity were also associated with increased CRT risk. 相似文献9.
10.
Prevalence, characteristics and the very existence of neurofibromatosis-associated diffuse lung disease remain unclear, mostly
because the few studies that looked at pulmonary involvement in such patients used chest X-ray as diagnostic mean. We report
on the clinical, functional and HRCT findings in a patient with neurofibromatosis-associated diffuse lung disease and provide
a short literature review. 相似文献