This study presented a pioneering investigation of the changes in the magnetic resonance imaging images of pectoralis major muscle (PMM) tendon rupture. In all, 26 men were evaluated with acute total PMM rupture (<3 months since injury) with a mean age of 37.3 years (SD = 9.
View Article and Find Full Text PDFTo compare outcomes between autologous fascia lata and autologous hamstring grafts for chronic pectoralis major muscle (PMM) rupture repair, and perform histological, and imaging analyses. Forty male patients with chronic PMM ruptures (time since injury ranging from >3 months to 5 years) and a mean age of 37.3 years (SD = 9.
View Article and Find Full Text PDFPectoralis major muscle tendon ruptures associated with physical activity or effort are no longer uncommon in the medical literature. Treatment has also evolved significantly in the last 20 years. However, simultaneous bilateral rupture has only been described in a few cases.
View Article and Find Full Text PDFIntroduction: Adolescence is marked by physiological and social changes, such as puberty, increased responsibilities and earlier school start times. This often leads to insufficient sleep on school nights and the need to compensate for lost sleep on weekends, causing a misalignment between biological and social times, which has been termed social jetlag (SJL). SJL triggers stress responses and is associated with several negative health outcomes, including higher cardiometabolic risk in adults.
View Article and Find Full Text PDFTo evaluate the electrophysiological activity of the injured pectoralis major (PM) muscle of operated patients who perform weightlifting, more specifically bench press exercises, especially the activity of the clavicular and sternocostal portions of the PM. All athletes in study I (10 patients) had unilateral complete ruptures during bench press exercises and a history of use of anabolic steroids, an association that is described in up to 86.7% of PM tendon ruptures.
View Article and Find Full Text PDFBackground: During the process of acclimatization, when our organism needs to adjust several metabolic processes in the attempt of establishing a better oxygenation, it is normal that individuals present some symptoms that can lead to the disease of the mountain. However, not everyone presents such symptoms and individuals native of high altitudes regions present genetic differences compared to natives of low altitudes which can generate a better acute adaptation. One of these differences is the higher proportion of type I muscle fibers, which may originate from the R577X polymorphism of the gene.
View Article and Find Full Text PDFIMPACT, a highly conserved protein, is an inhibitor of the eIF2α kinase GCN2. In mammals, it is preferentially expressed in neurons. Knock-down of IMPACT expression in neuronal cells increases basal GCN2 activation and eIF2α phosphorylation and decreases translation initiation.
View Article and Find Full Text PDFDrug delivery in research on nonhuman animals in the laboratory is still challenging because it is usually invasive and stressful. Stress-free voluntary oral drug administration in water lacks precise control of dose and timing of substance ingestion. Voluntary oral consumption of corticosterone has been previously successfully applied in mice using oat flakes, but protocols for oral corticosterone administration in rats remain unavailable.
View Article and Find Full Text PDFSleep deprivation is known to affect memory formation, but how it interacts with different memory systems is not completely understood. Adenosine, a homeostatic regulator of sleep that has an increased extracellular concentration during sleep deprivation, is one of the neuromodulators that may be involved in this interaction. The A adenosine receptor is involved in both sleep regulation and memory formation.
View Article and Find Full Text PDFChronic mild stress (CMS) is a widely accepted animal model relevant to depression that among other consequences, is chiefly known to induce anhedonia, often assessed as decreased preference for sucrose solution. CMS is also known to affect cognition, particularly memory tasks. In this study we have employed the multiple-trial inhibitory avoidance memory task (MTIA) to assess CMS effects on memory acquisition and retrieval.
View Article and Find Full Text PDFSleep deprivation impairs performance in emotional memory tasks, however this effect on memory is not completely understood. Possible mechanisms may involve an alteration in neurotransmission systems, as shown by the fact that many drugs that modulate neural pathways can prevent memory impairment by sleep loss. Gastrin releasing peptide (GRP) is a neuropeptide that emerged as a regulatory molecule of emotional memory through the modulation of other neurotransmission systems.
View Article and Find Full Text PDFChronic consumption of drugs with addictive potential induces profound synaptic changes in the dopaminergic mesocorticolimbic pathway that underlie the long-term behavioral alterations seen in addicted subjects. Thus, exploring modulation systems of dopaminergic function may reveal novel targets to interfere with drug addiction. We recently showed that cellular prion protein (PrP(C)) affects the homeostasis of the dopaminergic system by interfering with dopamine synthesis, content, receptor density and signaling pathways in different brain areas.
View Article and Find Full Text PDFCellular prion protein (PrP(C) ) is widely expressed in the brain. Although the precise role of PrP(C) remains uncertain, it has been proposed to be a pivotal modulator of neuroplasticity events by regulating the glutamatergic and serotonergic systems. Here we report the existence of neurochemical and functional interactions between PrP(C) and the dopaminergic system.
View Article and Find Full Text PDFThe present study addressed the effects of sleep deprivation (SD) on AMPA receptor (AMPAR) binding in brain regions associated with learning and memory, and investigated whether treatment with drugs acting on AMPAR could prevent passive avoidance deficits in sleep deprived animals. [(3)H]AMPA binding and GluR1 in situ hybridization signals were quantified in different brain regions of male Wistar rats either immediately after 96 h of sleep deprivation or after 24h of sleep recovery following 96 h of sleep deprivation. Another group of animals were sleep deprived and then treated with either the AMPAR potentiator, aniracetam (25, 50 and 100mg/kg, acute administration) or the AMPAR antagonist GYKI-52466 (5 and 10mg/kg, acute and chronic administration) before passive avoidance training.
View Article and Find Full Text PDFThe paraventricular nucleus (PVN) of the hypothalamus is an important region of the brain involved in the regulation of sympathetic vasomotor tone. Accumulating evidence supports the idea that a change in hypothalamic γ-aminobutyric acid (GABA)-ergic inhibitory and glutamatergic excitatory inputs contribute to the exacerbated sympathetic drive in chronic heart failure (HF). The purpose of this study was to determine whether a possible imbalance between glutamatergic and GABAergic inputs to the PVN contributes to increased sympathetic outflow in HF in two different sympathetic territories.
View Article and Find Full Text PDFWe investigated the relationship between deficits in fear memory induced by sleep deprivation and pCREB expression in the basal and central nuclei of the amygdala. Sleep deprivation reduced pCREB expression in the central nucleus compared to control or sleep recovered groups, and in the basal nucleus only compared to sleep recovered group. Moreover, 24h of sleep recovery prior to training prevented changes in both pCREB expression and performance.
View Article and Find Full Text PDFThe current study investigated the possible inherent relationship between convulsions and sleep involving the GABA(A)/benzodiazepine site complex. The aim of this study was to determine if rats with high (HTR) and low (LTR) thresholds for clonic convulsions induced by DMCM, a benzodiazepine inverse agonist, differ in the following aspects: (1) sensitivity to the hypnotic effects of the GABA(A) positive allosteric modulators diazepam, pentobarbital and ethanol and (2) in the binding of [(3)H]-flunitrazepam, a benzodiazepine agonist, measured by autoradiography, and [(3)H]-Ro 15-4513, a benzodiazepine partial inverse agonist, to membranes from discrete brain regions. The LTR subgroup presented a shorter diazepam-induced sleeping time compared to that of the HTR subgroup.
View Article and Find Full Text PDFBackground: Deep brain stimulation (DBS) is being investigated as a treatment for major depression, but its mechanisms of action are still unknown. We have studied the effects of ventromedial prefrontal cortex (vmPFC) stimulation in a chronic model of depression and assessed the involvement of the serotonergic system and brain derived neurotrophic factor (BDNF) in a DBS response.
Methods: Rats were subjected to chronic unpredictable mild stress during 4 weeks.
Brain areas expressing c-fos messenger RNA were mapped by quantitative in situ hybridization after 1-2 h of intoxication with 10 μg/kg Tx2-6, a toxin obtained from the venom of the spider Phoneutria nigriventer. Relative to saline-treated controls, brains from toxin-treated animals showed pronounced c-fos activation in many brain areas, including the supraoptic nucleus, the paraventricular nucleus of the hypothalamus, the motor nucleus of the vagus, area postrema, paraventricular and paratenial nuclei of the thalamus, locus coeruleus, central amydaloid nucleus and the bed nucleus of the stria terminalis. The paraventricular hypothalamus and the bed nucleus of the stria terminalis have been implicated in erectile function in other studies.
View Article and Find Full Text PDFSleep deprivation (SD) causes detrimental effects to the body, such as memory impairment and weight loss. SD also changes the concentration of inflammatory mediators such as cytokines, which, in turn, can affect cognitive functioning. Thus, the objective of this study was to investigate the involvement of these inflammatory mediators in inhibitory avoidance memory deficit in sleep-deprived rats.
View Article and Find Full Text PDFIncreasing evidence indicates that sleep deprivation alters behavioural responses to various pharmacological agents which might be associated to changes in receptor systems. The present work addressed the effects of sleep deprivation and recovery on behavioural changes induced by MK-801, and investigated whether such effects are related to changes in NMDA receptor (NMDAR) binding. Male Wistar rats were deprived of sleep for 96 h using the platform method (SD group), or were sleep deprived and then allowed to recover sleep for 24 h (SR group).
View Article and Find Full Text PDFStudy Objectives: Evaluation of modafinil effects on the inhibitory avoidance task (IA).
Design: Rats were trained on a multiple trial IA task after receiving modafinil or vehicle injections. In experiment 1 they were trained with a weak protocol under baseline condition and in experiment 2, with a stronger protocol under sleep-deprivation condition.
Increasing evidence indicates that sleep deprivation (SD) alters responses to pharmacological agents by affecting specific transmitter systems. The present work addressed deficits in passive avoidance (PA) performance that are seen after SD, and investigated whether treatment with the inverse benzodiazepine agonist beta-CCM could prevent such deficits. Male Wistar rats were deprived of sleep for 96 h using the platform method (SD group), or were sleep deprived and then allowed to recover sleep for 24h (SR group).
View Article and Find Full Text PDFBraz J Med Biol Res
March 2009
Sleep disturbances have far-reaching effects on the neuroendocrine and immune systems and may be linked to disease manifestation. Sleep deprivation can accelerate the onset of lupus in NZB/NZWF(1) mice, an animal model of severe systemic lupus erythematosus. High prolactin (PRL) concentrations are involved in the pathogenesis of systemic lupus erythematosus in human beings, as well as in NZB/NZWF(1) mice.
View Article and Find Full Text PDFAims: Hyperthermia is a characteristic functional effect of sleep deprivation (SD). We hypothesize here that prostaglandin E2 (PGE2) could be involved in hyperthermia induced by sleep deprivation.
Main Methods: To address this issue we examined the effects of a selective cyclo-oxygenase-2 inhibitor (COX-2) agent on hyperthermia induced by SD in rats.