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981.
In mammals and birds, hippocampal processing is crucial for allocentric spatial learning. In these vertebrate groups, lesions to the hippocampal formation produce selective impairments in spatial tasks that require the encoding of relationships among environmental features, but not in tasks that require the approach to a single cue or simple non-spatial discriminations. In reptiles, a great deal of anatomical evidence indicates that the medial cortex (MC) could be homologous to the hippocampus of mammals and birds; however, few studies have examined the functional role of this structure in relation to learning and memory processes. The aim of this work was to study how the MC lesions affect spatial strategies. Results of Experiment 1 showed that the MC lesion impaired the performance in animals pre-operatively trained in a place task, and although these animals were able to learn the same task after surgery, probe test revealed that learning strategies used by MC lesioned turtles were different to that observed in sham animals. Experiment 2 showed that the MC lesion did not impair the retention of the pre-operatively learned task when a single intramaze visual cue identified the goal. These results suggest that the reptilian MC and hippocampus of mammals and birds function in quite similar ways, not only in relation to those spatial functions that are impaired, but also in relation to those learning processes that are not affected. 相似文献
982.
Helantera I Koskinen P Tornroth T Loginov R Gronhagen-Riska C Lautenschlager I 《Transplantation》2003,75(11):1858-1864
BACKGROUND: The role of cytomegalovirus (CMV) in chronic kidney allograft rejection remains controversial. The purpose of this study was to examine the impact of CMV infection on histopathologic changes in 6-month protocol biopsy specimens of kidney allografts. METHODS: Altogether, 52 renal allograft recipients were studied. CMV infection was diagnosed by CMV antigenemia test, viral cultures from blood and urine, or both. CMV was demonstrated in the biopsy specimens by antigen detection and hybridization in situ. Acute rejections were diagnosed by biopsy histology, and biopsy specimens were graded according to the Banff '97 classification. RESULTS: CMV infection was diagnosed in 41 patients. The 11 patients in whom CMV infection was not detected were used as controls. Acute rejection was diagnosed in 22 of 41 CMV patients and in 6 of 11 control patients. CMV was demonstrated in the biopsy specimens of 19 of 41 CMV patients. CMV was not associated with increased glomerular, tubular, or interstitial changes. However, the arteriosclerotic changes in small arterioles were significantly increased in the subgroup of patients where CMV was demonstrated in the graft as compared with controls (P<0.01). Analysis of the impact of acute rejection on arteriolar thickening showed that only a positive history of both acute rejection and CMV found in the graft was associated with significantly increased vascular changes compared with CMV-free recipients (P<0.05). CONCLUSIONS: Neither CMV nor acute rejection alone was associated with increased vascular or other histopathologic changes in 6-month protocol biopsy specimens of kidney allografts, but a previous history of both acute rejection and the presence of CMV in the graft was associated with increased vascular changes. 相似文献
983.
In addition to RDH5, other enzymes capable of oxidizing 11-cis-retinol are present within the retinal pigment epithelium, Müller cells and/or photoreceptors. Candidate proteins have meanwhile been identified. To study the physiological and pathological aspects of these enzymes, mice in which these genes are no longer functional are being generated. A fast-targeting strategy for the disruption of genes was developed. Generation of double and triple knockouts will aid in determining if these retinol dehydrogenases are responsible for the remaining 11-cis-retinol oxidation observed in RDH5 knockout animals. 相似文献
984.
The present study was undertaken to determine the effects of catecholamines, agonists, and antagonists of beta-adrenergic receptors (AR) in the LNCaP cell line. Changes in cellular cyclic adenosine-3',5'-monophosphate (cAMP) levels were quantified by the use of a 6 cAMP response element (CRE)-luciferase reporter gene assay. LNCaP cells were transiently transfected with this gene construct, incubated in 96-well microtiter plates for 24 hr, and then treated with beta-AR agonists and/or antagonists for 4 hr. The rank order of potency for catecholamines and known beta-AR agonists was terbutaline(3.31 nM)>isoproterenol(8.31 nM)> or =fenoterol(15 nM)=epinephrine(16.2 nM)>norepinephrine(77.5 nM)>BRL-37344 [(R(*),R(*))-(+/-)4-[2-[(2-(3-chlorophenyl)-2-hydroxyethyl)amino]propyl]phenoxy acetic acid, sodium salt] (1000 nM)>dobutamine(1770 nM)>CGP12177 (4-[3-[(1,1-dimethylethyl)amino]-2-hydroxypropoxy]-1,3-dihydro-2H-benzimidazole-2-one hydrochloride) (inactive). The non-selective beta(1)-/-beta(2)-AR antagonists; propranolol and CGP 12177, at 10(-7)M, inhibited luciferase activity induced by these agonists by 80-96%. Propranolol blocked isoproterenol-induced luciferase responses in a competitive manner (K(B)=1.4 nM). In addition, isoproterenol-activated luciferase expression was blocked more potently by ICI 118,551 [(+/-)-1-[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethy) amino]-2-butanol], a beta(2)-AR antagonist than by ICI 89,406 [(+/-)-N-[2-[3-(2-cyanophenoxy-)]-2-hydroxypropylamino]ethyl-N-phenylurea], a beta(1)-AR antagonist, giving K(B) values of 1.07 and 161nM, respectively. These results suggest that the beta(2)-AR is the major subtype mediating catecholamine-induced cAMP changes in LNCaP cells. 相似文献
985.
Reelin controls granule cell migration in the dentate gyrus by acting on the radial glial scaffold 总被引:11,自引:1,他引:10
Reelin, synthesized and secreted by Cajal-Retzius (CR) cells in the marginal zone of the cortex, is an extracellular matrix protein important for the development of cortical layers. In reeler mutant mice lacking Reelin, there are severe malformations of neocortical and hippocampal lamination. It has been assumed that Reelin acts as a stop signal for migrating neurons. Here we show, by using the dentate gyrus as a model in in vivo studies and in vitro assays, that Reelin exerts its effects, at least in part, by acting on the radial glial scaffold required for neuronal migration. Migration defects of dentate granule cells, reminiscent of those seen in reeler mutants, are observed in tissue from patients with temporal lobe epilepsy (TLE). The extent of granule cell dispersion in TLE was found to be inversely correlated with the number of reelin mRNA synthesizing CR cells and reelin mRNA expression as revealed in quantitative RT-PCR studies. These findings show that the Reelin signaling pathway is essential for the correct positioning of human hippocampal neurons and that a Reelin deficiency is involved in the pathological changes associated with epilepsy. 相似文献
986.
Salas Campos L Gómez Ferrero O Ramal Muñoz I Villar Miranda H Martínez de la Chica AM 《Revista de enfermería (Barcelona, Spain)》2000,23(7-8):537-541
Antiseptics are chemical products which are applied on live tissues in order to eliminate microorganisms potentially pathogenic, or to inhibit their growth. The selection of the antiseptic must be done according to the properties and the recommended uses of the product. This article describes the main antiseptics used in the clinical practice, paying attention to its range of activity, recommended uses and toxicity. 相似文献
987.
988.
W. Schürmann Carola Zippel Th. Mertens H. J. Eggers 《Medical microbiology and immunology》1982,171(2):69-75
The performances of a vertical and a swinging bucket rotor in the diagnosis of rubella-specific IgM were compared using two sets of predominantly low titre rubella IgM positive sera. Applying a number of subtle criteria, the vertical rotor was shown to separate IgM and IgG less well than the swinging bucket rotor. If the vertical rotor was loaded with pretreated sera with IgG content decreased severalfold, its performance was similar to that of the swinging bucket rotor with native serum. The findings are discussed from the aspect of the main indication of rubella IgM testing, and it was concluded that for the majority of cases the vertical rotor would not present an alternative to the swinging bucket rotor. 相似文献
989.
990.
Whole blood glutathione peroxidase was found significantly increased relative to controls in a group of 21 black patients with sickle cell anaemia. One control group consisted of 15 normal black subjects. A second control group, consisting of 21 black patients with various abnormal haemoglobins including a-thalassaemia, also showed a tendency to enhanced glutathione peroxidase activity, confirming previous reports that elevated glutathione peroxidase levels are secondary to a variety of haemolytic conditions, rather than typical of sickle cell anaemia. 相似文献