排序方式: 共有93条查询结果,搜索用时 281 毫秒
71.
Caruso-Neves C Provenzano K Luz FF Santos FM Fernandes MS Leão-Ferreira LR Lopes AG 《Regulatory peptides》2003,110(3):207-212
Recently, we demonstrated that angiotensin-(1–7) (Ang-(1–7)) stimulates the Na+-ATPase activity through a losartan-sensitive angiotensin receptor, whereas bradykinin inhibits the enzyme activity through the B2 receptor [Regul. Pept. 91 (2000) 45; Pharmacol. Rev. 32 (1980) 1]. In the present paper, the effect of bradykinin (BK) on Ang-(1–7)-stimulated Na+-ATPase activity was evaluated. Preincubation of Na+-ATPase with 10−9 M Ang-(1–7) increases enzyme activity from 7.9±0.9 to 14.1±1.5 nmol Pi mg−1 min−1, corresponding to an increase of 79% (p<0.05). This effect is reverted by bradykinin in a dose-dependent manner (10−14–10−8 M), reaching maximal inhibitory effect at 10−9 M. Des-Arg9 bradykinin (DABK), an agonist of B1 receptor, at the concentrations of 10−9–10−7 M, does not mimic the BK inhibitory effect, and des-Arg9-[Leu8]-BK (DALBK), a B1 receptor antagonist, at the concentrations of 10−10–10−7 M, does not prevent the inhibitory effect of BK on Ang-(1–7)-stimulated enzyme. On the other hand, HOE 140, an antagonist of B2 receptor, abolishes the inhibitory effect of BK on the Ang-(1–7)-stimulated enzyme in a dose-dependent manner, reaching maximal effect at 10−7 M. Taken together, these data indicate that stimulation of B2 receptors by BK can counteract the stimulatory effect of Ang-(1–7) on the proximal tubule Na+-ATPase activity. 相似文献
72.
Paolo P. Provenzano Adriana L. Alejandro-Osorio Wilmot B. Valhmu Kristina T. Jensen Ray Vanderby Jr. 《Matrix biology》2005,23(8):543-555
Numerous studies have examined wound healing and tissue repair after a complete tissue rupture and reported provisional matrix and scar tissue formation in the injury gap. The initial phases of the repair are largely mediated by the coagulation response and a principally extrinsic inflammatory response followed by type III collagen deposition to form scar tissue that may be later remodeled. In this study, we examine subfailure (Grade II sprain) damage to collagenous matrices in which no gross tissue gap is present and a localized concentration of provisional matrix or scar tissue does not form. This results in extracellular matrix remodeling that relies heavily upon type I collagen, and associated proteoglycans, and less heavily on type III scar tissue collagen. For instance, following subfailure tissue damage, collagen I and III expression was suppressed after 1 day, but by day 7 expression of both genes was significantly increased over controls, with collagen I expression significantly larger than type III expression. Concurrent with increased collagen expression were significantly increased expression of the collagen fibrillogenesis supporting proteoglycans fibromodulin, lumican, decorin, the large aggregating proteoglycan versican, and proteases cathepsin K and L. Interestingly, this remodeling process appears intrinsic with little or no inflammation response as damaged tissues show no changes in macrophage or neutrophils levels following injury and expression of the inflammatory markers, tumor necrosis factor-alpha and tartrate-resistant acid phosphatase were unchanged. Hence, since inflammation plays a large role in wound healing by inducing cell migration and proliferation, and controlling extracellular matrix scar formation, its absence leaves fibroblasts to principally direct tissue remodeling. Therefore, following a Grade II subfailure injury to the collagen matrix, we conclude that tissue remodeling is fibroblast-mediated and occurs without scar tissue formation, but instead with type I collagen fibrillogenesis to repair the tissue. As such, this system provides unique insight into acute tissue damage and offers a potentially powerful model to examine fibroblast behavior. 相似文献
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The drosophilid assemblages of four cultivated areas (soy, bean, corn, and orange plantations) grown in the core of the Neotropical region were analyzed by comparing their abundances and compositions. The collections, which were gathered using 38 banana traps, captured 12,560 drosophilids, including nine Neotropical and six exotic species. Most of the flies were collected in the bean (43%) and soy (42%) fields. The composition and relative abundance of species also varied among cultivated areas, with orange orchards presenting the highest relative abundance of exotics due to the dominance of the Afrotropical Zaprionus indianus (Gupta). Crop plantations were dominated by a Neotropical species, Drosophila cardini (Sturtevant), which has been shown to be well adapted to dry and disturbed environments. We discuss the drosophilid assemblages of the cultivated areas, comparing them with assemblages from neighbor urban and natural environments. The low drosophilid richness found in this study is similar to the richness found in urban environments and lower than the drosophilid richness of forests, supporting a pattern already known for other taxa. The high abundance of drosophilids in cultivated areas, as well as the dominance of a Neotropical species (D. cardini) in the crop assemblages, was a surprising result. 相似文献
76.
Paolo P Provenzano Adriana L Alejandro-Osorio Kelley W Grorud Daniel A Martinez Arthur C Vailas Richard E Grindeland Ray VanderbyJr 《BMC physiology》2007,7(1):2
Background
Insulin-like growth factor-I (IGF-I) plays a crucial role in wound healing and tissue repair. We tested the hypotheses that systemic administration of IGF-I, or growth hormone (GH), or both (GH+IGF-I) would improve healing in collagenous connective tissue, such as ligament. These hypotheses were examined in rats that were allowed unrestricted activity after injury and in animals that were subjected to hindlimb disuse. Male rats were assigned to three groups: ambulatory sham-control, ambulatory-healing, and hindlimb unloaded-healing. Ambulatory and hindlimb unloaded animals underwent surgical disruption of their knee medial collateral ligaments (MCLs), while sham surgeries were performed on control animals. Healing animals subcutaneously received systemic doses of either saline, GH, IGF-I, or GH+IGF-I. After 3 weeks, mechanical properties, cell and matrix morphology, and biochemical composition were examined in control and healing ligaments. 相似文献77.
Summary. The in vitro and in vivo effects of two flavonons, naringenin (NG) and hesperitin (HP) on the proliferation rate of highly metastatic murine B16-F10
melanoma cell were investigated. NG or HP treatment of melanoma cells produced a remarkable reduction of cell proliferation,
paralleled with both the lowering of the intracellular levels of polyamine, spermidine and spermine and the enhancement of
transglutaminase (TGase, EC 2.3.2.13) activity. Orally administered NG or HP in C57BL6/N mice inoculated with B16-F10 cells
affected the pulmonary invasion of melanoma cells in an in vivo metastatic assay. The number of lung metastases detected by a computerized image analyzer was reduced, compared to untreated
animals, by about 69% in NG-treated mice and by about 36% in HP-treated mice. Survival studies showed that 50% of the NG-treated
animals died 38 ± 3.1 days after tumor cell injection (control group: 18 ± 1.5 days) and HP-treated mice died 27 ± 2.3 days
after cell inoculation. Taken together, these findings provide further evidences for the potential anticancer properties of
dietary flavonoids as chemopreventive agents against malignant melanoma. 相似文献
78.
Forni C Braglia R Lentini A Nuccetelli M Provenzano B Tabolacci C Beninati S 《Amino acids》2009,36(4):731-738
Flavonoids belong to the class of plant polyphenolic compounds with over 6,000 individual structures known. These phytochemicals
have attracted the interest of the scientists, because they possess a remarkable spectrum of biological activities, such as
antiallergic, antiinflammatory, antioxidant, antimutagenic and anticarcinogenic. In this work, we compared the anticancer
potential of two flavonoids, quercetin and pelargonidin, on highly metastatic B16-F10 melanoma murine cells. We have evaluated
different parameters related to cell proliferation and differentiation, such as cell number, toxicity, intracellular content
of polyamines and transglutaminase (TG, EC 2.3.2.13) activity. The higher inhibition of tumor cell growth, with respect to
control, was obtained with quercetin cell treatment, i.e. 32% reduction after 48 h and 39% reduction after 72 h of incubation
(P < 0.001). In parallel, quercetin-treated cells showed a similar decrease in polyamine content. TG activity was fourfold increased,
with respect to control, after 48 h and twofold increased after 72 h (P < 0.001). Pelargonidin treatment did not show significant antiproliferative effects and any increase in TG activity. Proteomic
approach was used to investigate changes in protein expression profiles in tumor cells following quercetin treatment. Changes
in expression of 60 proteins were detected, i.e. 8 proteins were down-regulated, 35 up-regulated, 11 “de novo” synthetized
proteins and 6 suppressed proteins were present in treated cells. A 80 kDa spot, identified as TG type 2 by Western blot analysis,
presented a fourfold increase in intensity, confirming the key role played by TG in the induction of cancer cell differentiation. 相似文献
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Gold salts and phenylbutazone selectively inhibit the synthesis of PGF2α and PGE2 respectively. Lowered production of one prostaglandin species is accompanied by an increased production of the other. Selective inhibition by these drugs was observed in the presence of adrenaline, reduced glutathione and copper sulphate under conditions when most anti-inflammatory compounds inhibited PGE2 and PGF2α syntheses equally. It is postulated that selective inhibitors may have a different mode of action in vivo and beneficial effects may be related to the endogenous ratio of PGE to PGF required for normal function. 相似文献