Training improves the oxidative phenotype of muscle during the transition from cardiac hypertrophy to heart failure without altering MyoD and myogenin.

What is the central question of this study? We investigated the effects of physical training on phenotypic (fibre-type content) and myogenic features (MyoD and myogenin expression) in skeletal muscle during the transition from cardiac hypertrophy to heart failure. What is the main finding and its importance? We provide new insight into skeletal muscle adaptations by showing that physical training increases the type I fibre content during the transition from cardiac hypertrophy to heart failure, without altering MyoD and myogenin expression. These results have important clinical implications for patients with heart failure, because this population has reduced muscle oxidative capacity.

Characterization of α-actin isoforms in white and red skeletal muscle types of Leporinus macrocephalus (Characiformes, Anostomidae).

Two α-actin genes of the fish Leporinus macrocephalus, referring to white and red muscle tissues, were isolated. Actin isoforms, that mainly differed by a Ser/Ala155 substitution, can have a functional significance related to actin-ATP interaction. An Ala155 residue, as observed in the α-skeletal actin from red muscle, results in a decrease in actin's affinity for ATP, which may also be associated to the slow contractile performance of this tissue.

Clinical, biomechanical and histological study on oophorectomy induced menopause.

Objective: To investigate the clinical implications as well as biomechanical and histological changes and in bone tissue induced by ovariectomy in 64 rats.

Methods: THE RATS WERE DIVIDED INTO TWO GROUPS: bilateral oophorectomy or placebo, and subdivided into four subgroups, according to time postoperatively: three, six, nine and 12 months. The weight of the animals at the time of sacrifice was taken into consideration.

Differential expression of a retrotransposable element, , in fish from different Amazonian environments.

Transposable elements (TEs) are DNA sequences that have the ability to move and replicate within the genomes. TEs can be classified according to their intermediates of transposition, RNA (retrotransposons) or DNA. In some aquatic organisms, it has been observed that environmental factors such as pH, temperature and pollution may stimulate differential transcription and mobilization of retrotransposons.

Muscle-specific growth hormone receptor (GHR) overexpression induces hyperplasia but not hypertrophy in transgenic zebrafish.

Even though growth hormone (GH) transgenesis has demonstrated potential for improved growth of commercially important species, the hormone excess may result in undesired collateral effects. In this context, the aim of this work was to develop a new model of transgenic zebrafish (Danio rerio) characterized by a muscle-specific overexpression of the GH receptor (GHR) gene, evaluating the effect of transgenesis on growth, muscle structure and expression of growth-related genes. In on line of transgenic zebrafish overexpressing GHR in skeletal muscle, no significant difference in total weight in comparison to non-transgenics was observed.

High-intensity resistance training with insufficient recovery time between bouts induce atrophy and alterations in myosin heavy chain content in rat skeletal muscle.

The aim of this study was to test whether high-intensity resistance training with insufficient recovery time between bouts, could result in a decrease of muscle fiber cross-sectional area (CSA), alter fiber-type frequencies and myosin heavy chain (MHC) isoform content in rat skeletal muscle. Wistar rats were divided into two groups: trained (Tr) and control (Co). Tr group were subjected to a high-intensity resistance training program (5 days/week) for 12 weeks, involving jump bouts into water, carrying progressive overloads based on percentage body weight.

Differential morphofunctional characteristics and gene expression in fast and slow muscle of rats with monocrotaline-induced heart failure.

Heart failure (HF) is characterized by limited exercise tolerance, skeletal muscle atrophy, a shift toward fast muscle fiber, and myogenic regulatory factor (MRF) changes. Reactive oxygen species (ROS) also contribute to target organ damage in this syndrome. In this study, we investigated and compared morphofunctional characteristics and gene expression in Soleus (SOL--oxidative and slow twitching muscle) and in Extensor Digitorum Longus (EDL--glycolytic and fast twitching muscle) during HF.

Long-term high-fat diet-induced obesity decreases the cardiac leptin receptor without apparent lipotoxicity.

Aims: Leptin resistance has been associated with cardiac lipotoxicity; however, whether leptin resistance is a risk factor associated with cardiac lipotoxicity at different time points in diet-induced obesity is unclear. The objective of this study was to evaluate this relationship.

Main Methods: Male Wistar rats were fed a normal chow diet (12% from fat) or a high-fat diet (49% from fat) for 15 and 45 weeks, respectively.

GH overexpression causes muscle hypertrophy independent from local IGF-I in a zebrafish transgenic model.

The aim of the present study was to analyse the morphology of white skeletal muscle in males and females from the GH-transgenic zebrafish (Danio rerio) lineage F0104, comparing the expression of genes related to the somatotrophic axis and myogenesis. Histological analysis demonstrated that transgenic fish presented enhanced muscle hypertrophy when compared to non-transgenic fish, with transgenic females being more hypertrophic than transgenic males. The expression of genes related to muscle growth revealed that transgenic hypertrophy is independent from local induction of insulin-like growth factor 1 gene (igf1).

Combined effect of the finasteride and doxazosin on rat ventral prostate morphology and physiology.

Finasteride (Fin) and Doxazosin (Dox), alone or in combination, have been widely used in treatment of benign prostatic hyperplasia (BPH) symptoms and recently have been suggested as potential drugs for prostate cancer (PCa)prevention and treatment. However, little is known about the effects of the combination therapy on prostate tissue morphology, physiology and matrix metalloproteinases (MMPs) activity, a special set of enzymes closely related to PCa progression and metastasis. In this study, adult Wistar rats were treated with Fin + Dox (25 mg/kg per day) and the ventral prostate (VP) was excised at days 3 and 30 of treatment to evaluate morphology, cell proliferation, death, transforming growth factor-beta1 (TGF-beta1) protein expression, MMP-2, MMP-9 activities and MMP-2, MMP-9, TIMP-1 and TIMP-2 mRNA expression.

Dietary restriction and fibre supplementation: oxidative stress and metabolic shifting for cardiac health.

Dietary modification ought to be the first line of strategy in prevention of the development of cardiac disease. The purpose of this study was to investigate whether dietary restriction, dietary-fibre-enriched diet, and their interactions might affect antioxidant capacity and oxidative stress in cardiac tissue. Male Wistar rats (180-200 g; n=10) were divided into four groups: control ad libitum diet (C), 50% restricted diet (DR), fed with fibre-enriched diet (F), and 50% restricted fibre-enriched diet (DR-F).

Morphology of ileal and jejunal pouches used as rectal substitutes.

Purpose: Our aim was to determine whether the mucosa of a canine jejunal pouch used as a rectal substitute after proctocolectomy retains its morphologic features better than the mucosa of a canine ileal pouch so used.

Methods: Among ten dogs that underwent proctocolectomy, five had a jejunal pouch-distal rectal anastomosis and five an ileal pouch-distal rectal anastomosis. After six months, the animals were killed, the intestinal pouches and portions of unaltered distal ileum were removed, and a blinded, mucosal morphometric analysis was performed.

Inside-out vein graft and inside-out artery graft in rat sciatic nerve repair.

Although veins and arteries present similar wall structures, there are differences which may be relevant in peripheral nerve reconstruction. Inside-out vein grafts (IOVG) have been satisfactorily used to repair both motor and sensitive nerves. However, the inside-out artery graft (IOAG) is a new technique and not fully investigated.

Satellite cells and myonuclei in neonatally denervated rat muscle.

While it is well know that the percentage of stellite cells in relation to myonuclei rapidly decreases in aneurally regenerating adult muscle, the fate of satellite cells in neonatally denervated muscles has received little attention so far. In the present study, rat tibialis anterior muscles were denervated at birth and analysed after 5, 7 and 10 weeks. At least 400 myonuclei in each muscle were assessed by electron microscopy and the percentage of satellite cell nuclei in relation to the number of myonuclei was calculated.