946 resultados para mesopredator release


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In cardiomyocytes, calcium (Ca2+) release units comprise clusters of intracellular Ca2+ release channels located on the sarcoplasmic reticulum, and hypertension is well established as a cause of defects in calcium release unit function. Our objective was to determine whether endurance exercise training could attenuate the deleterious effects of hypertension on calcium release unit components and Ca2+ sparks in left ventricular myocytes of spontaneously hypertensive rats. Male Wistar and spontaneously hypertensive rats (4 months of age) were divided into 4 groups: normotensive (NC) and hypertensive control (HC), and normotensive (NT) and hypertensive trained (HT) animals (7 rats per group). NC and HC rats were submitted to a low-intensity treadmill running protocol (5 days/week, 1 h/day, 0% grade, and 50-60% of maximal running speed) for 8 weeks. Gene expression of the ryanodine receptor type 2 (RyR2) and FK506 binding protein (FKBP12.6) increased (270%) and decreased (88%), respectively, in HC compared to NC rats. Endurance exercise training reversed these changes by reducing RyR2 (230%) and normalizing FKBP12.6 gene expression (112%). Hypertension also increased the frequency of Ca2+ sparks (HC=7.61±0.26 vs NC=4.79±0.19 per 100 µm/s) and decreased its amplitude (HC=0.260±0.08 vs NC=0.324±0.10 ΔF/F0), full width at half-maximum amplitude (HC=1.05±0.08 vs NC=1.26±0.01 µm), total duration (HC=11.51±0.12 vs NC=14.97±0.24 ms), time to peak (HC=4.84±0.06 vs NC=6.31±0.14 ms), and time constant of decay (HC=8.68±0.12 vs NC=10.21±0.22 ms). These changes were partially reversed in HT rats (frequency of Ca2+ sparks=6.26±0.19 µm/s, amplitude=0.282±0.10 ΔF/F0, full width at half-maximum amplitude=1.14±0.01 µm, total duration=13.34±0.17 ms, time to peak=5.43±0.08 ms, and time constant of decay=9.43±0.15 ms). Endurance exercise training attenuated the deleterious effects of hypertension on calcium release units of left ventricular myocytes.

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Nitric oxide (NO) is a soluble gas that participates in important functions of the central nervous system, such as cognitive function, maintenance of synaptic plasticity for the control of sleep, appetite, body temperature, neurosecretion, and antinociception. Furthermore, during exercise large amounts of NO are released that contribute to maintaining body homeostasis. Besides NO production, physical exercise has been shown to induce antinociception. Thus, the present study aimed to investigate the central involvement of NO in exercise-induced antinociception. In both mechanical and thermal nociceptive tests, central [intrathecal (it) and intracerebroventricular (icv)] pretreatment with inhibitors of the NO/cGMP/KATP pathway (L-NOArg, ODQ, and glybenclamide) prevented the antinociceptive effect induced by aerobic exercise (AE). Furthermore, pretreatment (it, icv) with specific NO synthase inhibitors (L-NIO, aminoguanidine, and L-NPA) also prevented this effect. Supporting the hypothesis of the central involvement of NO in exercise-induced antinociception, nitrite levels in the cerebrospinal fluid increased immediately after AE. Therefore, the present study suggests that, during exercise, the NO released centrally induced antinociception.

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This study aimed to determine the effects of different concentrations of propofol (2,6-diisopropylphenol) on lipopolysaccharide (LPS)-induced expression and release of high-mobility group box 1 protein (HMGB1) in mouse macrophages. Mouse macrophage cell line RAW264.7 cells were randomly divided into 5 treatment groups. Expression levels of HMGB1 mRNA were detected using RT-PCR, and cell culture supernatant HMGB1 protein levels were detected using enzyme-linked immunosorbent assay (ELISA). Translocation of HMGB1 from the nucleus to the cytoplasm in macrophages was observed by Western blotting and activity of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in the nucleus was detected using ELISA. HMGB1 mRNA expression levels increased significantly in the cell culture supernatant and in cells after 24 h of stimulating RAW264.7 cells with LPS (500 ng/mL). However, HMGB1 mRNA expression levels in the P2 and P3 groups, which received 500 ng/mL LPS with 25 or 50 μmol/mL propofol, respectively, were significantly lower than those in the group receiving LPS stimulation (P<0.05). After stimulation by LPS, HMGB1 protein levels were reduced significantly in the nucleus but were increased in the cytoplasm (P<0.05). Simultaneously, the activity of NF-κB was enhanced significantly (P<0.05). After propofol intervention, HMGB1 translocation from the nucleus to the cytoplasm and NF-κB activity were inhibited significantly (each P<0.05). Thus, propofol can inhibit the LPS-induced expression and release of HMGB1 by inhibiting HMGB1 translocation and NF-κB activity in RAW264.7 cells, suggesting propofol may be protective in patients with sepsis.

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Heavy metals, such as methylmercury, are key environmental pollutants that easily reach human beings by bioaccumulation through the food chain. Several reports have demonstrated that endocrine organs, and especially the pituitary gland, are potential targets for mercury accumulation; however, the effects on the regulation of hormonal release are unclear. It has been suggested that serum prolactin could represent a biomarker of heavy metal exposure. The aim of this study was to evaluate the effect of methylmercury on prolactin release and the role of the nitrergic system using prolactin secretory cells (the mammosomatotroph cell line, GH3B6). Exposure to methylmercury (0-100 μM) was cytotoxic in a time- and concentration-dependent manner, with an LC50 higher than described for cells of neuronal origin, suggesting GH3B6 cells have a relative resistance. Methylmercury (at exposures as low as 1 μM for 2 h) also decreased prolactin release. Interestingly, inhibition of nitric oxide synthase by N-nitro-L-arginine completely prevented the decrease in prolactin release without acute neurotoxic effects of methylmercury. These data indicate that the decrease in prolactin production occurs via activation of the nitrergic system and is an early effect of methylmercury in cells of pituitary origin.

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Microparticles obtained by complex coacervation were crosslinked with glutaraldehyde or with transglutaminase and dried using freeze drying or spray drying. Moist samples presented Encapsulation Efficiency (%EE) higher than 96%. The mean diameters ranged from 43.7 ± 3.4 to 96.4 ± 10.3 µm for moist samples, from 38.1 ± 5.36 to 65.2 ± 16.1 µm for dried samples, and from 62.5 ± 7.5 to 106.9 ± 26.1 µm for rehydrated microparticles. The integrity of the particles without crosslinking was maintained when freeze drying was used. After spray drying, only crosslinked samples were able to maintain the wall integrity. Microparticles had a round shape and in the case of dried samples rugged walls apparently without cracks were observed. Core distribution inside the particles was multinuclear and homogeneous and core release was evaluated using anhydrous ethanol. Moist particles crosslinked with glutaraldehyde at the concentration of 1.0 mM.g-1 protein (ptn), were more efficient with respect to the core retention compared to 0.1 mM.g-1 ptn or those crosslinked with transglutaminase (10 U.g-1 ptn). The drying processes had a strong influence on the core release profile reducing the amount released to all dry samples

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Most tropical forage grass species have dormant seeds, which reduce percentages in germination tests. The objective of this study was to evaluate H2SO4 scarification effects on seed dormancy releasing, through germination time (T50) and variability among germination test replicates, in 630, 94 and 82 seed samples of B. brizantha, B. humidicola and P. maximum, respectively, tested at the Central Seed Testing Laboratory, Campinas, Brazil, from 1991 to 1999. Germination tests used two 4 x 100 replicates of intact and scarified seeds (15-, 10-, 5-minute treatments, respectively). Mean germination time (T50) and variability among germination replicates were also analysed. Statistical analysis was performed by t-test paired samples for means. Scarification promoted general decreases in T50, while variability among germination test replicates was reduced in B. brizantha. Scarification increase germination in B. brizantha and P. maximum, but is deleterious in B. humidicola.

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A media release from Inniskillin Wines announcing the launch of "Alliánce", a joint winemaking venture between Inniskillin and Jaffelin Wines of France.

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A News Release draft to be sent to "100 newspapers, radio and television stations (virtually all those with offices within 20 miles of the Lakes), make them available to the Press Gallery, special interest groups, trade publication and Mayors etc. of Great Lake-side communities". The release discusses the need for an upgrade to "the 1972 Canada-U.S. Great Lakes Water Quality agreement". Within the document, O'Sullivan is quoted that the agreement "should be upgraded to become a treaty with the United States, so that after all the effort which has already been put into tyring to clean up the Great Lakes we the provision which provides for cancellation by either party giving twelve months (notice) to do so". The total report is 61 pages in length.

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A press release from Youth for Diefenbaker, 1 August 1967. The release reads: "Hamilton Student Appointed Youth for Dief Representative. The youngest delegate to the conservative leadership convention, 15 year old Sean O'Sullivan of Hamilton, has been named Western Ontario representative of the Youth for Diefenbaker movement. This movement was formed in Ottawa to engage support of Canada's young conservatives for John Diefenbaker at the leadership convention. According to Mr. O'Sullivan, there is growing support for Mr. Diefenbaker and he will have an announcement to make in that regard at a press conference on Friday August Fourth at the Connaught Hotel."

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A press release assigning Sean O'Sullivan to study the future of the Great Lakes and St. Lawrence Seaway.

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Indenture of release regarding a loan of 12, 500 pounds which Samuel Zimmerman (deceased) is said to have lent and advanced to the Woodstock and Lake Erie Railway and Harbour Company. This is put forward by the executors who include: Joseph A. Woodruff, Richard Woodruff, John L. Ranney and Richard Miller. This document releases and exonerates the Railway Company from any debts to the executors. [The outside of the document says 1857, but the actual date is Feb. 10, 1858].

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Indenture of release stating that all existing contracts and agreements made by the Woodstock and Lake Erie Railway Co. are cancelled. This release was between the executors of Samuel Zimmerman's will and the Woodstock and Lake Erie Railway Co. February 10, 1858.

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Indenture of release by executors between Richard Miller, John L. Ranney and Richard Woodruff, all of St. Catharines and Joseph A. Woodruff of Clifton, all executors of the will of Samuel Zimmerman of the first part and The Great Western Railway Company of the second part. Parties of the second part have exonerated parties of the first part to undertake and complete the Sarnia branch of the railway. Also, parties of the first part believe they are entitled to compensation as the death of Zimmerman was caused while travelling on one of the carriages belonging to said company. A sum of $150,000 was agreed upon to be paid to the executors by the Great Western Railway Company, September 7, 1858.

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UANL