Search results for "RATS"
showing 10 items of 3537 documents
The aging heart, myocardial fibrosis, and its relationship to circulating C-type natriuretic Peptide.
2011
Myocardial aging is characterized by left ventricular (LV) fibrosis leading to diastolic and systolic dysfunction. Studies have established the potent antifibrotic and antiproliferative properties of C-type natriuretic peptide (CNP); however, the relationship between circulating CNP, LV fibrosis, and associated changes in LV function with natural aging are undefined. Accordingly, we characterized the relationship of plasma CNP with LV fibrosis and function in 2-, 11-, and 20-month–old male Fischer rats. Further in vitro, we established the antiproliferative actions of CNP and the participation of the clearance receptor using adult human cardiac fibroblasts. Here we establish for the first t…
Fracture Mechanics of Collagen Fibrils: Influence of Natural Cross-Links
2013
AbstractTendons are important load-bearing structures, which are frequently injured in both sports and work. Type I collagen fibrils are the primary components of tendons and carry most of the mechanical loads experienced by the tissue, however, knowledge of how load is transmitted between and within fibrils is limited. The presence of covalent enzymatic cross-links between collagen molecules is an important factor that has been shown to influence mechanical behavior of the tendons. To improve our understanding of how molecular bonds translate into tendon mechanics, we used an atomic force microscopy technique to measure the mechanical behavior of individual collagen fibrils loaded to failu…
Mechanism of Free Radical Production in Exhaustive Exercise in Humans and Rats; Role of Xanthine Oxidase and Protection by Allopurinol
2000
Exhaustive exercise generates free radicals, However, the source of this oxidative damage remains controversial. The aim of this paper was to study further the mechanism of exercise-induced production of free radicals, Testing the hypothesis that xanthine oxidase contributes to the production of free radicals during exercise, me found not only that exercise caused an increase in blood xanthine oxidase activity in rats but also that inhibiting xanthine oxidase with allopurinol prevented exercise-induced oxidation of glutathione in both rats and in humans. Furthermore, inhibiting xanthine oxidase prevented the increases in the plasma activity of cytosolic enzymes (lactate dehydrogenase, aspar…
Testosterone and aggressiveness.
2003
Aggressiveness is an ancestral behavior common to all animal species. Its neurophysiological mechanisms are similar in all vertebrates. Males are generally more aggressive than females. In this review, aggressive behavior in rodents, monkeys, and man and the role of testosterone and brain serotonin levels have been considered. Interspecifi c aggressiveness in rats has been studied considering the mouse-killing behavior; the neonatal androgenization of females increases adult mousekilling as does the administration of testosterone in adults. Intraspecifi c aggressiveness was studied by putting two or more male rats (or mice) in the same cage; the condition of subjection or dominance is infl …
Age-related increase in xanthine oxidase activity in human plasma and rat tissues.
2007
This study assessed the role of xanthine oxidase in vascular ageing. A positive correlation between xanthine oxidase activity and age was found in human plasma. Similar results were found in rat plasma. Xanthine oxidase expression and activity in homogenates from the aortic wall were significantly higher in samples from old rats than in their young counterparts (p<0.01). In rat skeletal muscle homogenates both xanthine oxidase expression and activity showed a similar age-related profile. Superoxide production by xanthine oxidase in aortic rings was higher in aged rats. Uric acid, the final product of xanthine oxidase has been proposed as a risk factor for coronary heart disease and an indep…
Effect of Conjugated Linoleic Acid on Testosterone Levels In Vitro and In Vivo After an Acute Bout of Resistance Exercise
2012
The purposes of the present study were to investigate the effect of conjugated linoleic acid (CLA) supplementation on testosterone levels in vitro on a cell line derived from Leydig cells (R2C) and in vivo in the blood of physically active subjects before and after a resistance exercise bout. In vitro R2C cells were treated with different CLA concentrations (0-30 μM) for 24 and 48 hours. After treatment, supernatant media were tested to determine testosterone secretion. The CLA increased the testosterone secretion only after 48 hours. In vivo, 10 resistance-trained male subjects, in a double-blind placebo-controlled and crossover study design were randomized for 3 weeks of either 6 g·d⁻¹ CL…
Immunosuppressive treatment in bilateral vestibulopathy with inner ear antibodies.
2005
Although vestibular recovery was observed after steroid treatment, it remains uncertain whether this improvement was spontaneous or due to medication. These data do not allow us to generally recommend corticosteroid treatment in patients with BVF and inner ear antibodies.A retrospective study was performed based on the observation of two patients with suspected autoimmune bilateral vestibular failure (BVF) with normal hearing and antilabyrinthine or nervous tissue-specific serum antibodies who showed vestibular recovery after corticosteroid treatment.Twelve patients with BVF and serum inner ear antibodies who had received imuunosuppressive treatment with corticosteroids were evaluated in te…
Cytosolic epoxide hydrolase in humans: development and tissue distribution.
1988
Cytosolic epoxide hydrolase activity was measured towards trans-stilbene oxide in 41 human adult livers, in 40 fetal livers, in 17 placentas and in fetal and adult lungs, kidneys and gut. The cytosolic epoxide hydrolase activity was measurable in all specimens investigated. The rate of formation of trans-stilbene glycol (pmol/min per mg protein, mean +/- SD) was 55.2 +/- 89.6 (fetal liver). 303.2 +/- 73.2 (adult liver) and 18.8 +/- 13.1 (placenta) In the fetal extrahepatic tissues, the cytosolic epoxide hydrolase activity was 70.0 +/- 9.4 (adrenals), 47.6 +/- 7.2 (gut), 69.4 +/- 22.5 (kidneys) and 43.2 +/- 19.2 (lungs) pmol/min per mg protein, whereas in the adult tissues it was 131.2 +/- 6…
Inhibition of glial proliferation in vitro by serum from patients with multiple sclerosis
1987
Primary cell cultures from fetal rat CNS have been employed to evaluate the effects caused by the addition of serum from patients affected by multiple sclerosis (MS). MS-serum supplemented media caused a decrease in [3H]-thymidine incorporation into the cultures, thus indicating an inhibitory effect on proliferating glial cells. Sera from patients in remission stage of the disease showed an inhibitory effect not significatively lower than those from patients in acute stage. These results suggest that glial cells may be a target of circulating factors present in MS.
Role of Erythropoietin in Cerebral Glioma: An Innovative Target in Neuro-Oncology
2019
Background: Erythropoietin (EPO) is a cytokine primarily involved in the regulation of erythropoiesis. In response to hypoxia–ischemia, hypoxia-inducible factor 1 induces EPO production, which, in turn, inhibits apoptosis of erythroid progenitor cells. By the same mechanism and acting through other signaling pathways, EPO exerts neuroprotective effects. Increased resistance to hypoxia and decreased apoptosis are thought to be important mechanisms for tumor progression, including malignant glioma. Because recent studies have demonstrated that EPO and its receptor (EPOR) are expressed in several tumors and can promote tumor growth, in the present study, we investigated EPO and EPOR expression…