Effects of perinatal protein deprivation and recovery on esophageal myenteric plexus

AIM: To evaluate effects of pre- and postnatal protein deprivation and postnatal recovery on the myenteric plexus of the rat esophagus. METHODS: Three groups of young Wistar rats (aged 42 d) were studied: normal-fed (N42), protein-deprived (D42), and protein-recovered (R42). The myenteric neurons of their esophagi were evaluated by histochemical reactions for nicotinamide adenine dinucleotide (NADH), nitrergic neurons (NADPH)-diaphorase and acetylcholinesterase (AChE), immunohistochemical reaction for vasoactive intestinal polypeptide (VIP), and ultrastructural analysis by transmission electron microscopy. RESULTS: The cytoplasms of large and medium neurons from the N42 and R42 groups were intensely reactive for NADH. Only a few large neurons from the D42 group exhibited this aspect. NADPH detected in the D42 group exhibited low reactivity. The AChE reactivity was diffuse in neurons from the D42 and R42 groups. The density of large and small varicosities detected by immunohistochemical staining of VIP was low in ganglia from the D42 group. In many neurons from the D42 group, the double membrane of the nuclear envelope and the perinuclear cisterna were not detectable. NADH and NADPH histochemistry revealed no group differences in the profile of nerve cell perikarya (ranging from 200 to 400 mu m(2)). CONCLUSION: Protein deprivation causes a delay in neuronal maturation but postnatal recovery can almost completely restore the normal morphology of myenteric neurons. (C) 2010 Baishideng. All rights reserved.

Identification of COL6A1 as a differentially expressed gene in human astrocytomas

Diffuse infiltrating gliomas are the most common tumors of the central nervous system. Gliomas are classified by the WHO according to their histopathological and clinical characteristics into four classes: grade I (pilocytic astrocytoma), grade II (diffuse astrocytoma), grade III (anaplastic astrocytoma), and grade IV (glioblastoma multiforme). Several genes have already been correlated with astrocytomas, but many others are yet to be uncovered. By analyzing the public SAGE data from 21 patients, comprising low malignant grade astrocytomas and glioblastomas, we found COL6A1 to be differentially expressed, confirming this finding by real time RT-PCR in 66 surgical samples. To the best of our knowledge, COL6A1 has never been described in gliomas. The expression of this gene has significantly different means when normal glia is compared with low-grade astrocytomas (grades I and II) and high-grade astrocytomas (grades III and IV), with a tendency to be greater in higher grade samples, thus rendering it a powerful tumor marker.

Psychogenetics of Turner syndrome: an investigation of 28 subjects and respective controls using the Bender test and Piagetian scales

Piagetian scales and the Bender visual motor gestalt test (BT) were applied to 28 subjects with universal 45, X Turner syndrome (TS), and their respective controls, in order to investigate their cognitive performance. Dermatoglyphics were also analyzed to obtain clues concerning embryological changes that may have appeared during development of the nervous system and could be associated with cognitive performance of TS patients. Dermatoglyphic pattern distribution was similar to that reported in previous studies of TS individuals: ulnar loops in the digital patterns and finger ridge, a-b, and A'-d counts were more frequent, while arch and whorl patterns were less frequent compared to controls. However, we did not find higher frequencies of hypothenar pattern, maximum atd angle, and ulnarity index in our TS subjects, unlike other investigations. Furthermore, we found significant differences between TS and control T line index values. The BT scores were also lower in probands, as has been previously reported, revealing a neurocognitive deficit of visual motor perception in TS individuals, which could be due to an absence of, or deficiency in, cerebral hemispheric lateralization. However, TS subjects seemed to improve their performance on BT with age. Cognitive performance of the TS subjects was not significantly different from that of controls, confirming a previous study in which TS performance was found to be similar to that of the normal Brazilian population. There were significant correlations between BT scores and Piagetian scale levels with dermatoglyphic parameters. This association could be explained by changes in the common ectodermal origin of the epidermis and the central nervous system. TS subjects seem to succeed in compensating their spatial impairments in adapting their cognitive and social contacts. We concluded that genetic counseling should consider cognitive and psychosocial difficulties presented by TS subjects, providing appropriate treatment and orientation for them and their families.

Retinoic Acid-Treated Pluripotent Stem Cells Undergoing Neurogenesis Present Increased Aneuploidy and Micronuclei Formation

The existence of loss and gain of chromosomes, known as aneuploidy, has been previously described within the central nervous system. During development, at least one-third of neural progenitor cells (NPCs) are aneuploid. Notably, aneuploid NPCs may survive and functionally integrate into the mature neural circuitry. Given the unanswered significance of this phenomenon, we tested the hypothesis that neural differentiation induced by all-trans retinoic acid (RA) in pluripotent stem cells is accompanied by increased levels of aneuploidy, as previously described for cortical NPCs in vivo. In this work we used embryonal carcinoma (EC) cells, embryonic stem (ES) cells and induced pluripotent stem (iPS) cells undergoing differentiation into NPCs. Ploidy analysis revealed a 2-fold increase in the rate of aneuploidy, with the prevalence of chromosome loss in RA primed stem cells when compared to naive cells. In an attempt to understand the basis of neurogenic aneuploidy, micronuclei formation and survivin expression was assessed in pluripotent stem cells exposed to RA. RA increased micronuclei occurrence by almost 2-fold while decreased survivin expression by 50%, indicating possible mechanisms by which stem cells lose their chromosomes during neural differentiation. DNA fragmentation analysis demonstrated no increase in apoptosis on embryoid bodies treated with RA, indicating that cell death is not the mandatory fate of aneuploid NPCs derived from pluripotent cells. In order to exclude that the increase in aneuploidy was a spurious consequence of RA treatment, not related to neurogenesis, mouse embryonic fibroblasts were treated with RA under the same conditions and no alterations in chromosome gain or loss were observed. These findings indicate a correlation amongst neural differentiation, aneuploidy, micronuclei formation and survivin downregulation in pluripotent stem cells exposed to RA, providing evidence that somatically generated chromosomal variation accompanies neurogenesis in vitro.

Continuous monitoring of ascorbate transport through neuroblastoma cells with a ruthenium oxide hexacyanoferrate modified microelectrode

The uptake of ascorbate by neuroblastoma cells using a ruthenium oxide hexacyanoferrate (RuOHCF)-modified carbon fiber disc (CFD) microelectrode (r = 14.5 mu m) was investigated. By use of the proposed electrochemical sensor the amperometric determination of ascorbate was performed at 0.0 V in minimum essential medium (MEM, pH = 7.2) with a limit of detection of 25 mu mol L(-1). Under the optimum experimental conditions, no interference from MEM constituents and reduced glutathione (used to prevent the oxidation of ascorbate during the experiments) was noticed. The stability of the RuOHCF-modified electrode response was studied by measuring the sensitivity over an extended period of time (120 h), a decrease of around 10% being noticed at the end of the experiment. The rate of ascorbate uptake by control human neuroblastoma SH-SY5Y cells, and cells transfected with wild-type Cu,Zn-superoxide dismutase (SOD WT) or with a mutant typical of familial amyotrophic lateral sclerosis (SOD G93A), was in agreement with the level of oxidative stress in these cells. The usefulness of the RuOHCF-modified microelectrode for in vivo monitoring of ascorbate inside neuroblastoma cells was also demonstrated.

Double disruption of alpha(2A)- and alpha(2C)-adrenoceptors results in sympathetic hyperactivity and high-bone-mass phenotype

Evidence demonstrates that sympathetic nervous system (SNS) activation causes osteopenia via beta(2)-adrenoceptor (beta(2)-AR) signaling. Here we show that female mice with chronic sympathetic hyperactivity owing to double knockout of adrenoceptors that negatively regulate norepinephrine release, alpha(2A)-AR and alpha(2C)-AR(alpha(2A)/alpha(2C)-ARKO), present an unexpected and generalized phenotype of high bone mass with decreased bone resorption and increased formation. In alpha(2A)/alpha(2C)-ARKO versus wild-type (WT) mice, micro-computed tomographic (mu CT) analysis showed increased, better connected, and more plate-shaped trabeculae in the femur and vertebra and increased cortical thickness in the vertebra, whereas biomechanical analysis showed increased tibial and femoral strength. Tibial mRNA expression of tartrate-resistant acid phosphatase (TRACP) and receptor activator of NF-kappa B (RANK), which are osteoclast-related factors, was lower in knockout (KO) mice. Plasma leptin and brain mRNA levels of cocaine amphetamine-regulated transcript (CART), which are factors that centrally affect bone turnover, and serum levels of estradiol were similar between mice strains. Tibial beta(2)-AR mRNA expression also was similar in KO and WT littermates, whereas alpha(2A)-, alpha(2B)- and alpha(2C)-AR mRNAs were detected in the tibia of WT mice and in osteoblast-like MC3T3-E1 cells. By immunohistochemistry, we detected alpha(2A)-, alpha(2B)-, alpha(2C)- and beta(2)-ARs in osteoblasts, osteoclasts, and chondrocytes of 18.5-day-old mouse fetuses and 35-day-old mice. Finally, we showed that isolated osteoclasts in culture are responsive to the selective alpha(2)-AR agonist clonidine and to the nonspecific alpha-AR antagonist phentolamine. These findings suggest that beta(2)-AR is not the single adrenoceptor involved in bone turnover regulation and show that alpha(2)-AR signaling also may mediate the SNS actions in the skeleton. (c) 2011 American Society for Bone and Mineral Research.

Neuromuscular activity during bench press exercise performed with and without the preexhaustion method

Brennecke, A, Guimaraees, TM, Leone, R, Cadarci, M, Mochizuki, L, Simao, R, Amadio, AC, and Serrao, J. Neuromuscular activity during bench press exercise performed with and without the preexhaustion method. J Strength Cond Res 23(7): 1933-1940, 2009-The purpose of the present study was to investigate the effects of exercise order on the tonic and phasic characteristics of upper-body muscle activity during bench press exercise in trained subjects. The preexhaustion method involves working a muscle or a muscle group combining a single-joint exercise immediately followed by a multi-joint exercise (e. g., flying exercise followed by bench press exercise). Twelve subjects performed 1 set of bench press exercises with and without the preexhaustion method following 2 protocols (P1-flying before bench press; P2-bench press). Both exercises were performed at a load of 10 repetition maximum (10RM). Electromyography (EMG) sampled at 1 kHz was recorded from the pectoralis major (PM), anterior deltoid (DA), and triceps brachii (TB). Kinematic data (60 Hz) were synchronized to define upward and downward phases of exercise. No significant (p > 0.05) changes were seen in tonic control of PM and DA muscles between P1 and P2. However, TB tonic aspect of neurophysiologic behavior of motor units was significantly higher (p < 0.05) during P1. Moreover, phasic control of PM, DA, and TB muscles were not affected (p > 0.05). The kinematic pattern of movement changed as a result of muscular weakness in P1. Angular velocity of the right shoulder performed during the upward phase of the bench press exercise was significantly slower (p < 0.05) during P1. Our results suggest that the strategies set by the central nervous system to provide the performance required by the exercise are held constant throughout the exercise, but the tonic aspects of the central drive are increased so as to adapt to the progressive occurrence of the neuromuscular fatigue. Changes in tonic control as a result of the muscular weakness and fatigue can cause changes in movement techniques. These changes may be related to limited ability to control mechanical loads and mechanical energy transmission to joints and passive structures.

Intracellular mechanisms of specific beta-adrenoceptor antagonists involved in improved cardiac function and survival in a genetic model of heart failure

beta-blockers, as class, improve cardiac function and survival in heart failure (HF). However, the molecular mechanisms underlying these beneficial effects remain elusive. In the present study, metoprolol and carvedilol were used in doses that display comparable heart rate reduction to assess their beneficial effects in a genetic model of sympathetic hyperactivity-induced HF (alpha(2A)/alpha(2C)-ARKO mice). Five month-old HF mice were randomly assigned to receive either saline, metoprolol or carvedilol for 8 weeks and age-matched wild-type mice (WT) were used as controls. HF mice displayed baseline tachycardia, systolic dysfunction evaluated by echocardiography, 50% mortality rate, increased cardiac myocyte width (50%) and ventricular fibrosis (3-fold) compared with WT. All these responses were significantly improved by both treatments. Cardiomyocytes from HF mice showed reduced peak [Ca(2+)](i) transient (13%) using confocal microscopy imaging. Interestingly, while metoprolol improved [Ca(2+)](i) transient, carvedilol had no effect on peak [Ca(2+)](i) transient but also increased [Ca(2+)] transient decay dynamics. We then examined the influence of carvedilol in cardiac oxidative stress as an alternative target to explain its beneficial effects. Indeed, HF mice showed 10-fold decrease in cardiac reduced/oxidized glutathione ratio compared with WT, which was significantly improved only by carvedilol treatment. Taken together, we provide direct evidence that the beneficial effects of metoprolol were mainly associated with improved cardiac Ca(2+) transients and the net balance of cardiac Ca(2+) handling proteins while carvedilol preferentially improved cardiac redox state. (C) 2008 Elsevier Inc. All rights reserved.

The influence of peripheral afferent signals on the rating of perceived exertion and time to exhaustion during exercise at different intensities

This study determined which peripheral variables would better predict the rating of perceived exertion (RPE) and time to exhaustion (TE) during exercise at different intensities. Ten men performed exercises at first lactate threshold (LT1), second lactate threshold (LT2), 50% of the distance from LT1 to LT2 (TT(50%)), and 25% of the distance from LT2 to maximal power output (TW(25%)). Lactate, catecholamines, potassium, pH, glucose, (V) over dotO(2), VE, HR, respiratory rate (RR) and RPE were measured and plotted against the exercise duration for the slope calculation. Glucose, dopamine, and noradrenaline predicted RPE in TT(50%) (88%), LT2 (64%), and TW(25%) (77%), but no variable predicted RPE in LT1. RPE (55%), RPE+HR (86%), and RPE+RR (92% and 55%) predicted TE in LT1, TT(50%), LT2, and TW(25%), respectively. At intensities from TT(50%) to TW(25%), variables associated with brain activity seem to explain most of the RPE slope, and RPE (+HR and+RR) seems to predict the TE.

Role of brain nitric oxide in the thermoregulation of broiler chicks

Nitric oxide (NO) plays a key role in body temperature (Tb) regulation of mammals, acting on the brain to stimulate heat loss. Regarding birds, the putative participation of NO in the maintenance of Tb in thermoneutrality or during heat stress and the site of its action (periphery or brain) is unknown. Thus, we tested if NO participates in the maintenance of chicks` Tb in those conditions. We investigated the effect of intramuscular (im; 25, 50, 100 mg/kg) or intracerebroventricular (icv; 22.5, 45, 90, 180 mu g/animal) injections of the non selective NO synthase inhibitor L-NAME on Tb of 5-day-old chicks at thermoneutral zone (TNZ; 31-32 degrees C) and under heat stress (37 degrees C for 5-6 h). We also verified plasma and diencephalic nitrite/nitrate levels in non-injected chicks under both conditions. At TNZ, 100 mg/kg (im) or 45,90,180 mu g (icv) of L-NAME decreased Tb. A significant correlation between Tb and diencephalic, but not plasma, nitrite/nitrate levels was observed. Heat stress-induced hyperthermia was inhibited by all tested doses of L-NAME (im and icv). Tb was correlated neither with plasma nor with diencephalic nitrite/nitrate levels during heat stress. These results indicate the involvement of brain NO in the maintenance of Tb of chicks, an opposite action of that observed in mammals, and may modulate hyperthermia. (C) 2009 Elsevier Inc. All rights reserved.

Vibratory noise to the fingertip enhances balance improvement associated with light touch

Light touch of a fingertip on an external stable surface greatly improves the postural stability of standing subjects. The hypothesis of the present work was that a vibrating surface could increase the effectiveness of fingertip signaling to the central nervous system (e.g., by a stochastic resonance mechanism) and hence improve postural stability beyond that achieved by light touch. Subjects stood quietly over a force plate while touching with their right index fingertip a surface that could be either quiescent or randomly vibrated at two low-level noise intensities. The vibratory noise of the contact surface caused a significant decrease in postural sway, as assessed by center of pressure measures in both time and frequency domains. Complementary experiments were designed to test whether postural control improvements were associated with a stochastic resonance mechanism or whether attentional mechanisms could be contributing. A full curve relating body sway parameters and different levels of vibratory noise resulted in a U-like function, suggesting that the improvement in sway relied on a stochastic resonance mechanism. Additionally, no decrease in postural sway was observed when the vibrating contact surface was attached to the subject`s body, suggesting that no attentional mechanisms were involved. These results indicate that sensory cues obtained from the fingertip need not necessarily be associated with static contact surfaces to cause improvement in postural stability. A low-level noisy vibration applied to the contact surface could lead to a better performance of the postural control system.

High frequency tendon reflexes in the human soleus muscle

Tendon reflexes have been often used in studies of the human nervous system in health and disease. They have been investigated either in response to single tendon taps or to long duration vibrations. Tendon reflexes are described here in response to a high frequency vibration burst (3 cycles of a 100 Hz sine wave) applied to the Achilles tendon of standing subjects, either in quiet stance or during a forward leaning posture. The electromyogram from the soleus muscle usually showed three components separated by 10 ms which were interpreted as being three reflexes, each reflex induced by each of the three cycles in a burst. This result indicates that soleus tendon reflexes can respond in fast succession in a phasic manner when a brief high frequency vibration is applied to the Achilles tendon. This occurs in spite of possible depression of the la to motoneuron synapses and the long after hyperpolarization of the motoneurons. An interpretation of the results is that motoneurons from different subsets of the motoneuron pool respond to different cycles of the sinusoidal vibratory burst. (c) 2008 Elsevier Ireland Ltd. All rights reserved.

Characterization of the electrocardiographic pattern of individuals with cerebral palsy

Background: Dentists of Lar Sao Francisco observed during dental treatment that children with cerebral palsy (CP) had increased heart rate (HR) and lower production of saliva. Despite the high prevalence of CP found in the literature (2.08-3.6/1000 individuals), little is known about the electrocardiographic (ECG) characteristics, especially HR, of individuals with CP. Objective: This study aimed to investigate the hypothesis that individuals with CP have a higher HR and to define other ECG characteristics of this population. Methods: Ninety children with CP underwent clinical examination and 12-lead rest ECG. Electrocardiographic data on rhythm, HR, PR interval, QRS duration, P/QRS/T axis, and QT, QTc and T(peak-end) intervals (minimum, mean, maximum, and dispersion) were measured and analyzed then compared with data from a control group with 35 normal children. Fisher and Mann-Whitney U tests were used, respectively, to compare categorical and continuous data. Results: Groups cerebral palsy and control did not significantly differ in age (9 +/- 3 x 9 +/- 4 years) and male gender (65% x 49%). Children with CP had a higher HR (104.0 +/- 20.6 x 84.2 +/- 13.3 beats per minute; P < .0001), shorter PR interval (128.8 +/- 15.0 x 138.1 +/- 15.1 milliseconds; P = .0018), shorter QRS duration (77.4 +/- 8.6 x 82.0 +/- 8.7 milliseconds; P = .0180), QRS axis (46.0 degrees +/- 26.3 degrees x 59.7 degrees +/- 24.8 degrees; P = .0024) and T-wave axis (34.3 degrees +/- 28.9 degrees x 42.9 degrees +/- 17.1 degrees; P = .034) more horizontally positioned, and greater mean QTc (418.1 +/- 18.4 x 408.5 +/- 19.4 milliseconds; P = .0110). All the electrocardiogram variables were within the reference range for the age group including those with significant differences. Conclusion: Children with CP showed increased HR and other abnormal ECG findings in the setting of this investigation. Further studies are needed to explain our findings and to correlate the increased HR with situations such as dehydration, stress, and autonomic nervous disorders. (C) 2011 Elsevier Inc. All rights reserved.

Neuropharmacological effects in mice of Lychnophora species (Vernonieae, Asteraceae) and anticonvulsant activity of 4,5-di-O-[E]-caffeoylquinic acid isolated from the stem of L-rupestris and L-staavioides

Aiming at contributing with the search for neuroactive substances from natural sources, we report for the first time antinociceptive and anticonvulsant effects of some Lychnophora species. We verify the protective effects of polar extracts (600 mg/kg, intraperitoneally), and methanolic fractions of L. staavioides and L. rupestris (100 mg/kg, intraperitoneally) in pentylenetetrazole-induced seizures on mice. Previously, a screening was accomplished, evaluating the antinociceptive central activity (hot plate test), with different extracts of L. rupestris, L. staavioides and L. diamantinana. It was possible to select the possible extracts of Lychnophora with central nervous system activity. Some of the active extracts were submitted to fractionation and purification process and the methanolic fractions of L. rupestris (stem) and L. staavioides (stem), with anticonvulsant properties (100 mg/kg, intraperitoneally), yielded 4,5-di-O-[E]-caffeoylquinic acid. This substance was injected intraperitoneally in mice and showed anticonvulsant effect against pentylenetetrazole-induced seizures at doses of 25 and 50 mg/kg. It has often been shown that seizures induced by pentylenetetrazole are involved in inhibition and/or attenuation of GABAergic neurotransmission. However, other systems of the central nervous system such as adenosinergic and glutamatergic could be involved in the caffeoylquinic acid effects. Further studies should be conducted to verify that the target receptor could be participating in this anticonvulsant property. Although other investigations have reported a series of biological activities from Lychnophora species, this is the first report of central analgesic and anticonvulsant activity in species of this genus.

Increase of core temperature induced by corticotropin-releasing factor and urocortin: A comparative study

This study compared the ability of CRF and UCN1 to induce a thermoregulatory response when centrally injected into rats. The effects of antipyretic drugs and CRF receptor antagonists (CRF(1) and CRF(2)) on the temperature (T) changes induced by these peptides were also investigated. Rectal (rT) and tail skin (T(sk)) temperatures were measured with a thermistor probe while body (bT) temperature was measured with a battery-operated biotelemetry transmitter in male Wistar rats (200 g) every 30 min over a period of 6 h, after intracerebroventricular (i.c.v.) injection of 1 nmol of either CRF or UCN1. Rats were pre-treated with indomethacin (2 mg kg(-1), i.p.) or celecoxib (5 mg kg(-1), p.o.), dexamethasone (0.5 mg kg(-1), s.c.), astressin (a CRF(1)/CRF(2) antagonist, 7 nmol, icy.) or antalarmin (a CRF(1) antagonist, 20 mg kg 1, i.p.). The increase in body temperature induced by CRF was accompanied by a reduction in T(sk) while the response induced by UCN1 was accompanied by an elevation in T(sk). Indomethacin or celecoxib did not change the increases in rT caused by either CRF or UCN1. Although dexamethasone attenuated the increase in rectal temperature in response to CRF, dexamethasone did not modify the response induced by UCN1. Astressin blocked the UCN1-induced hyperthermia and reduced CRF-induced fever. Antalarmin did not modify the hyperthermia in response to UCN1, but reduced the fever evoked by CRF. This study demonstrated that CRF by acting on the CRF(1) receptor induces a prostaglandin-independent fever which seems to depend, at least in part, on the synthesis of other mediators while UCN1 acts on the CRF(2) receptor, promoting a hyperthermic response which seems to be independent on synthesis/release of any mediator. (C) 2010 Elsevier B.V. All rights reserved.