Biological research
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Biological research · Jan 2014
Association of serum total bilirubin levels with diastolic dysfunction in heart failure with preserved ejection fraction.
Left ventricular diastolic dysfunction is one of the main characteristics of heart failure patients with a preserved left ventricular ejection fraction. As bilirubin is regarded as an important endogenous antioxidant molecule, serum total bilirubin levels were compared between heart failure patients with a preserved left ventricular ejection fraction and normal controls in this study. We recruited 327 heart failure patients with a preserved left ventricular ejection fraction and 200 healthy controls. Patients were divided into 4 subgroups by their comprehensive echocardiographic manifestations, 1-mild, 2-moderate, 3-severe (reversible restrictive), 4-severe (fixed restrictive). Total bilirubin levels were compared using stepwise multiple regressions adjusted for selected factors. ⋯ TB level was negatively correlated with left ventricular diastolic dysfunction in heart failure patients with a preserved left ventricular ejection fraction, which might provide a new insight into the complicated mechanisms of heart failure with a preserved left ventricular ejection fraction.
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Biological research · Jan 2011
Mechanical ventilation and volutrauma: study in vivo of a healthy pig model.
Mechanical ventilation is essential in intensive care units. However, it may itself induce lung injury. Current studies are based on rodents, using exceptionally large tidal volumes for very short periods, often after a "priming" pulmonary insult. ⋯ On autoptic samples we performed zymographic analysis of lung, kidney and liver tissues and histological examination of lung. Results evidenced that high Vt evoked profound alterations of lung mechanics and structure, although low Vt strategy was not devoid of side effects, too. Unexpectedly, also animals that were spontaneously breathing showed a worsening of the respiratory functions.
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Biological research · Jan 2010
Correlations of recognition memory performance with expression and methylation of brain-derived neurotrophic factor in rats.
Object recognition memory allows discrimination between novel and familiar objects. This kind of memory consists of two components: recollection, which depends on the hippocampus, and familiarity, which depends on the perirhinal cortex (Pcx). The importance of brain-derived neurotrophic factor (BDNF) for recognition memory has already been recognized. ⋯ We found a significant correlation between performance on the novel object task and the expression of BDNF, negatively in hippocampal slices and positively in perirhinal cortical slices. By contrast, methylation of DNA in CpG island 1 in the promoter of exon 1 in BDNF only correlated in hippocampal slices, but not in the Pxc cortical slices from trained animals. These results suggest that DNA methylation may be involved in the regulation of the BDNF gene during recognition memory, at least in the hippocampus.
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Biological research · Jan 2009
Upregulation of liver inducible nitric oxide synthase following thyroid hormone preconditioning: suppression by N-acetylcysteine.
3,3-5-L-Triiodothyronine (T(3)) exerts significant protection against ischemia-reperfusion (IR) liver injury in rats. Considering that the underlying mechanisms are unknown, the aim of this study was to assess the involvement of inducible nitric oxide synthase (iNOS) expression and oxidative stress in T(3) preconditioning (PC). ⋯ T(3) protected against hepatic IR injury, with 119% enhancement in liver iNOS mRNA/18S rRNA ratios (p<0.05) and 12.7-fold increase (p<0.05) in NOS activity in T(3)-treated animals subjected to IR over values in control-sham operated rats, with a net 7.7-fold enhancement (p<0.05) in the net effect of T(3) on liver iNOS expression and a net enhancement of 0.58 units in NOS activity, changes that were abolished by NAC treatment before T(3). It is concluded that T(3)-induced liver PC is associated with upregulation of iNOS expression as a protective mechanisms against IR injury, which is achieved through development of transient and reversible oxidative stress.
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Biological research · Jan 2008
Long lasting structural changes in primary motor cortex after motor skill learning: a behavioural and stereological study.
Many motor skills, once acquired, are stored over a long time period, probably sustained by permanent neuronal changes. Thus, in this paper we have investigated with quantitative stereology the generation and persistence of neuronal density changes in primary motor cortex (MI) following motor skill learning (skilled reaching task). Rats were trained a lateralised reaching task during an "early" (22-31 days old) or "late" (362-371 days old) postnatal period. ⋯ It is concluded that learning a skilled reaching task implies long lasting structural changes in restricted cortical regions of the motor cortex. The generation and persistence of these changes probably reflect a plastic reorganization for storing and retrieving motor skills. The plastic changes were also observed in the older rats, suggesting that motor cortex maintains its plastic capacity throughout the lifespan.