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51.

Background  

The human umbilical cord contains mucoid connective tissue and fibroblast-like cells. These cells named Wharton's jelly cells, (WJCs) display properties similar to mesenchymal stem cells therefore representing a rich source of primitive cells to be potentially used in regenerative medicine.  相似文献   
52.
Metallothioneins are cysteine-rich, metal-binding proteins ubiquitously expressed in living organisms. In the last past years, a plethora of vertebrate metallothionein sequences have become available, but so far there has been an almost absolute lack of data about sequences of metallothionein of non-avian diapsida. In the framework of the investigations on structural and functional properties of non-mammalian metallothioneins, we have cloned and sequenced the cDNAs encoding for metallothioneins of 10 squamate reptiles, belonging to 5 different infraorders. These sequences have been used to gain insight into the evolutionary history of metallothioneins in reptiles. Phylogenetic analysis shows that reptilian metallothionein phylogeny is inconsistent with the species phylogeny. Such findings allow us to hypothesize that the identified metallothionein in each squamate species used for this study might be considered a paralogous gene derived from more events of gene duplication and losses occurred during the diversification of the squamate species. Finally, through vertebrate metallothionein comparisons and phylogenetic analysis, we also add a novel contribution to the understanding of the evolution of metallothionein genes along the major vertebrate lineages.  相似文献   
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The stereoselectivity of carvedilol, a novel beta-adrenoceptor antagonist and vasodilator with one asymmetric carbon atom, was examined at alpha 1- and beta 1-adrenoceptors in vitro and in vivo. (-)-(S)-Carvedilol is a potent, competitive antagonist of the beta 1-adrenoceptor-mediated positive chronotropic response to isoproterenol in guinea pig atrium, with a dissociation constant (KB) of 0.4 nM. (+)-(R)-Carvedilol was more than 100-fold less potent than the (-)-S-enantiomer as an antagonist of beta 1-andrenoceptors, having a KB of approximately 45 nM. Consistent with these findings (-)-(S)-carvedilol (0.1 mg/kg, i.v.) produced a 25-fold rightward shift in the beta 1-adrenoceptor-mediated positive chronotropic response to isoproterenol in pithed rats, whereas the (+)-R-enantiomer had no beta 1-adrenoceptor blocking activity in vivo at this dose. In contrast to the marked degree of stereoselectivity observed at beta 1-adrenoceptors, both (-)-(S)- and (+)-(R)-carvedilol produced equal antagonism of the alpha 1-adrenoceptor-mediated vasoconstrictor response to norepinephrine in rabbit aorta, with KB values of 14 and 16 nM, respectively. Furthermore, in the pithed rat, the alpha 1-adrenoceptor-mediated pressor dose-response curve to cirazoline was shifted approximately 6-fold to the right by both the (+)-R- and (-)-S-enantiomers of carvedilol at a dose of 1 mg/kg, i.v. In anesthetized spontaneously hypertensive rats, (-)-(S)-carvedilol was 6-fold more potent as an antihypertensive than (+)-(R)-carvedilol.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
56.
Selective progesterone receptor modulators (SPRMs) have been suggested as therapeutic agents for treatment of gynecological disorders. One such SPRM, asoprisnil, was recently in clinical trials for treatment of uterine fibroids and endometriosis. We present the crystal structures of progesterone receptor (PR) ligand binding domain complexed with asoprisnil and the corepressors nuclear receptor corepressor (NCoR) and SMRT. This is the first report of steroid nuclear receptor crystal structures with ligand and corepressors. These structures show PR in a different conformation than PR complexed with progesterone (P4). We profiled asoprisnil in PR-dependent assays to understand further the PR-mediated mechanism of action. We confirmed previous findings that asoprisnil demonstrated antagonism, but not agonism, in a PR-B transfection assay and the T47D breast cancer cell alkaline phosphatase activity assay. Asoprisnil, but not RU486, weakly recruited the coactivators SRC-1 and AIB1. However, asoprisnil strongly recruited the corepressor NCoR in a manner similar to RU486. Unlike RU486, NCoR binding to asoprisnil-bound PR could be displaced with equal affinity by NCoR or TIF2 peptides. We further showed that it weakly activated T47D cell gene expression of Sgk-1 and PPL and antagonized P4-induced expression of both genes. In rat leiomyoma ELT3 cells, asoprisnil demonstrated partial P4-like inhibition of cyclooxygenase (COX) enzymatic activity and COX-2 gene expression. In the rat uterotrophic assay, asoprisnil demonstrated no P4-like ability to oppose estrogen. Our data suggest that asoprisnil differentially recruits coactivators and corepressors compared to RU486 or P4, and this specific cofactor interaction profile is apparently insufficient to oppose estrogenic activity in rat uterus.  相似文献   
57.
An orangutan (Pongo abelii) presented with chronic respiratory problems. Cytological evaluation of the bronchoalveolar lavage fluids revealed macrophages with well‐circumscribed intracytoplasmic clear vacuoles and lipid droplets in the background, confirmed by Oil Red O staining. The findings were indicative of lipoid pneumonia. This is the first report of lipoid pneumonia in an orangutan.  相似文献   
58.

Objectives

To study the effects of age and cognition on the performance of children aged 3 to 18 years on a culturally adapted version of the 16 item smell identification test from Sniffin'' Sticks (SS16).

Methods

A series of pilots were conducted on 29 children aged 3 to 18 years old and 23 adults to produce an adapted version of the SS16 suitable for Brazilian children (SS16-Child). A final version was applied to 51 children alongside a picture identification test (PIT-SS16-Child) to access cognitive abilities involved in the smell identification task. In addition 20 adults performed the same tasks as a comparison group.

Results

The final adapted SS16-Child was applied to 51 children with a mean age of 9.9 years (range 3-18 years, SD=4.25 years), of which 68.3% were girls. There was an independent effect of age (p<0.05) and PIT-SS16-Child (p<0.001) on the performance on the SS16-Child, and older children reached the ceiling for scoring in the cognitive and olfactory test. Pre-school children had difficulties identifying items of the test.

Discussion/Conclusions

A cross-culturally adapted version of the SS16 can be used to test olfaction in children but interpretation of the results must take age and cognitive abilities into consideration.  相似文献   
59.
Tensin is a protein confined at those discrete and specialized regions of the plasma membrane, known as focal adhesions. It contains, at the C-terminus, a phosphotyrosine binding (PTB) domain that can interact with the cytoplasmic tail of beta-integrins and is necessary for localization of the protein to cell-matrix adhesions. Here, we present the NMR solution structure of the PTB domain of tensin1. Moreover, through NMR binding studies, we demonstrate that the PTB domain of tensin1 is able to interact with phosphatidylinositol 4, 5-diphosphate (PtIns(4,5)P2) and phosphatidylinositol 4-phosphate (PtIns(4)P), presenting higher affinity for the diphosphorylated inositide. Chemical shift mapping studies reveal a putative PtIns(4,5)P2 binding region that is distinct from the predicted integrin beta-tail recognition site. Heteronuclear NOE experiments, recorded in absence and presence of PtIns(4,5)P2, indicate that the interaction with lipids decreases the flexibility of loop regions, predicted to be important for integrin binding, and thus, proposes a possible correlation between the two distinct binding events. Therefore, our studies suggest that capture of lipids by the PTB domain of tensin1 may play a role for the protein function at focal adhesions.  相似文献   
60.
Leone M  Cellitti J  Pellecchia M 《Biochemistry》2008,47(48):12721-12728
Sterile alpha motif (Sam) domains are protein interaction modules that are implicated in many biological processes mainly via homo- and heterodimerization. It has been recently reported that the lipid phosphatase Ship2 regulates endocytosis of the EphA2 receptor, a process that has been investigated as a possible route to reduce tumor malignancy. A heterotypic Sam-Sam domain interaction is mediating this process. Here, we report NMR and ITC (isothermal titration calorimetry) studies on the Sam domain of Ship2 revealing its three-dimensional structure and its possible mode of interaction with the Sam domain from the EphA2 receptor. These studies have also resulted in the identification of a minimal peptide region of Ship2 that retains binding affinity for the Sam domain of the EphA2 receptor. Hence, this peptide and the detection of key structural elements important for EphA2 receptor endocytosis provide possible ways for the development of novel small molecule antagonists with potential anticancer activity.  相似文献   
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