Skeletal muscle differentiation: role of dehydroepiandrosterone sulfate.

Dehydroepiandrosterone (DHEA) and its sulfonated form dehydroepiandrosterone sulfate (DHEAS) are the main circulating steroid hormones and many epidemiological studies show an inverse relationship between DHEA/DHEAS levels and muscle loss for which the primary cause is the accelerated protein breakdown. The aim of this work was to determine whether DHEA/DHEAS supplementation in differentiating C2C12 skeletal muscle cells might influence the expression of the atrophy-related ubiquitin ligase, MuRF-1, and thereby impact key molecules of the differentiation program. DHEA is the prohormone crucial for sex steroid synthesis, and DHEAS is thought to be its reservoir. However, our preliminary experiments showed that DHEAS, but not DHEA, is able to influence MuRF-1 expression. Therefore, we treated differentiating C2C12 cells with various concentrations of DHEAS and analyzed the expression of MuRF-1, Hsp70, myosin heavy chain (MHC), myogenin, and the activity of creatine kinase. We observed that DHEAS at physiological concentrations downregulates MuRF-1 expression and affects muscle differentiation, as shown by the increased levels of MHC, which is a sarcomeric protein that undergoes MuRF-1-dependent degradation, and also by an increase in creatine kinase activity and myogenin expression, which are two other well-known markers of differentiation. Moreover, we found that DHEAS might have a protective effect on differentiating cells as suggested by the augmented levels of Hsp70, a member of heat shock proteins family that, besides its cytoprotective action, seems to have a regulatory role on key atrophy genes such as MuRF-1. In conclusion, our data shed light on the role of DHEAS at physiologic concentrations in maintaining muscle mass.

Effects of chronic Rhodiola Rosea supplementation on sport performance and antioxidant capacity in trained male: preliminary results.

AIM: Rhodiola Rosea, is an adaptogen plant which has been reported to promote fatty acids utilisation, to ameliorate antioxidant function, and to improve body resistance to physical strenuous efforts. The purpose of the present study was to investigate the effects on physical performance as well as on the redox status of a chronic Rhodiola Rosea supplementation in a group of competitive athletes during endurance exercise. METHODS: Following a chronic supplementation with Rhodiola Rosea for 4 weeks, 14 trained male athletes underwent a cardio-pulmonary exhaustion test and blood samples to evaluate their antioxidant status and other biochemical parameters. These data were compared with those coming from the same athletes after an intake of placebo. RESULTS: The evaluation of physical performance parameters showed that HR Max, Borg Scale level, VO(2) max and duration of the test were essentially unaffected by Rhodiola Rosea assumption. On the contrary, Rhodiola Rosea intake reduced, in a statistically significative manner, plasma free fatty acids levels. No effect on blood glucose was found. Blood antioxidant status and inflammatory parameters resulted unaffected by Rhodiola Rosea supplementation. Blood lactate and plasma creatine kinase levels were found significantly lower (P<0.05) in Rhodiola Rosea treated subjects when compared to the placebo treated group. CONCLUSION: Chronic Rhodiola Rosea supplementation is able to reduce both lactate levels and parameters of skeletal muscle damage after an exhaustive exercise session. Moreover this supplementation seems to ameliorate fatty acid consumption. Taken together those observation confirm that Rhodiola Rosea may increase the adaptogen ability to physical exercise.

Activity and regulation of calcium-, phospholipid-dependent protein kinase in differentiating chick myogenic cells.

The activity of calcium-, phospholipid-dependent protein kinase (PKc) was measured in (a) total extracts, (b) crude membrane, and (c) cytosolic fractions of chick embryo myogenic cells differentiating in culture. Total PKc activity slowly declines during the course of terminal myogenesis in contrast to the activity of cAMP-dependent protein kinase, which was also measured in the same cells. Myogenic cells at day 1 of culture possess high particulate and low soluble PKc activity. A dramatic decline of particulate PKc activity occurs during myogenic cell differentiation and is accompanied, through day 4, by a striking rise of the soluble activity. The difference in the subcellular distribution of PKc between replicating myoblasts and myotubes is confirmed by phosphorylation studies conducted in intact cells. These studies demonstrate that four polypeptides whose phosphorylation is stimulated by the tumor promoter 12-O-tetradecanoyl phorbol 13-acetate in myotubes, are spontaneously phosphorylated in control myoblasts. Phosphoinositide turnover under basal conditions in [3H]inositol-labeled cells is faster in myoblasts than in myotubes, a finding that may in part explain the different distribution of PKc observed during the course of myogenic differentiation.

Expression of a ryanodine receptor-Ca2+ channel that is regulated by TGF-beta.

Ryanodine receptors (RyRs) are intracellular channels that release calcium ions from the sarcoplasmic reticulum (SR) in response to either plasma membrane depolarization (in skeletal muscle) or increases in the concentration of intracellular free Ca2+ (in the heart). A gene (beta 4) encoding a ryanodine receptor (similar to, but distinct from, the muscle RyRs) was identified. The beta 4 gene was expressed in all tissues investigated, with the exception of heart. Treatment of mink lung epithelial cells (Mv1Lu) with transforming growth factor beta (TGF-beta) induced expression of the beta 4 gene together with the release of Ca2+ in response to ryanodine (but not in response to caffeine, the other drug active on muscle RyRs). This ryanodine receptor may be important in the regulation of intracellular Ca2+ homeostasis.

[Epidemiological impact of RV gastroenteritis in the Abruzzo Region: SDO analysis]. / Impatto epidemiologico delle gastroenteriti da Rotavirus nella Regione Abruzzo: analisi delle SDO.

RV represent the principle cause of acute gastroenteritis in infants in the world. In developing countries they are responsible for a high mortality rate in children under the age of five, whereas, in industrialized countries the RV infection is mainly related to hospitalisation. In order to study the epidemiological impact of enteritis caused by RV, we used the SDO files (hospital discharge code) in the Abruzzo Region relative to the years 2003-2006. Of a total number of 3146 children under the age of 5 who were diagnosed with gastroenteritis at the moment of hospitalisation, 1025 presented gastroenteritis of viral origin and 48.4% (496) due to RV. Furthermore, 253 hospital admissions were observed for RV in a second diagnosis. Infants of 12-23 months are those subject to the highest rate of hospitalisation ranging from 295/100.000 and 517/100.000. The use of the SDO files can determine an underestimation of the hospitalisation incidence for RV because to confirm a correct diagnosis the analysis of faeces should be systematically carried out but this is not always undertaken. The implementation of a secure and efficient vaccine strategy seems to be justified in poor countries, whereas in the industrialized countries, such a strategy can reduce the health expenditure for gastroenteritis by RV.

In vitro osteoclastogenesis from Gaucher patients' cells correlates with bone mineral density but not with Chitotriosidase.

Gaucher disease (GD) is caused by mutations on the gene encoding for the lysosomal enzyme glucocerebrosidase. Type I GD (GD1) patients present anemia, hepatosplenomegaly and bone alterations. In spite of treatment, bone alterations in GD patients persist, including poor bone mineral density (BMD). Mechanisms leading to bone damage are not completely understood, but previous reports suggest that osteoclasts are involved. Chitotriosidase (CHIT) is the most reliable biomarker used in the follow up of patients, although its correlation with bone status is unknown. The aim of this work was to study the pro-osteoclastogenic potential in patients and to evaluate its correlation with CHIT activity levels and clinical parameters. PBMCs from treated patients and healthy controls were cultured in the presence of M-CSF, and mature osteoclasts were counted. BMD, blood CHIT activity and serum levels of CTX, BAP, and cytokines were evaluated in patients. We found that blood CHIT activity and osteoclast differentiation were significantly increased in patients, but no correlation between them was observed. Interestingly, osteoclast numbers but not CHIT, presented a negative correlation with BMD expressed as Z-score. CTX, BAP and serum cytokines involved in bone remodeling were found altered in GD1 patients. These results show for the first time a correlation between osteoclast differentiation and BMD in GD1 patients, supporting the involvement of osteoclasts in the bone pathology of GD1. Our results also suggest that an altered immune response may play an important role in bone damage.

Nonsurgical embryo recovery and transfer in sheep and goats.

The embryo transfer techniques used in small ruminants worldwide are based in surgical procedures. These actions are performed under general anesthesia which needs a combination of animal fasting and drugs for secure animal handling and surgery manipulations. Therefore, it involves risks to animal health and life. The major limiting sequels are adhesions formed by the abdominal surgery, in the ovaries, uterus, or between them. These occurrences can both compromise uterus accessing and oocyte capture and are responsible for decreasing success and limiting successive embryo collections. In contrast, nonsurgical embryo procedures can be performed in a relatively simplified way. Nonsurgical embryo recovery does not need animal prolonged starvation, drug retention is minimized, and donors can stay in a standing position. After the end of embryo recovery, donors are promptly restored to their routine housing and feeding. Furthermore, this technique does not need incisions and, therefore, can be used repetitively in superovulated or nonsuperovulated goats and sheep for embryo recovery-a similar procedure done in cattle. In Brazil, promising results are reported using nonsurgical embryo transfer in recipient goats, and studies are currently evaluating similar procedures in sheep. Therefore, this review aimed to present the current panorama of nonsurgical embryo transfer in sheep and goats.

Effect of AP1 transcription factors on the regulation of transcription in normal human epidermal keratinocytes.

The conversion of basal keratinocytes to spinous and granular cells is accompanied by the synthesis of a series of epidermal proteins in a differentiation-specific pattern. The transcription of several of these epidermal marker genes is regulated by activator protein 1 (AP1) interactions at their promoter regions. In the epidermis the various AP1 transcription factors are not present uniformly but appear to have a differentiation-specific distribution. We have explored whether the AP1 regulated expression of the keratin 5, transglutaminase 1, involucrin, and loricrin genes reflects the distribution of the AP1 factors in the epidermis. We have found that c-jun and junD activate and junB downregulates the transcription of both basal and suprabasal genes. The effect of c-jun is exerted through interactions with c-fos at the AP1 motifs in the target promoters, whereas both junB and junD act independently of the binding at the AP1 sites. Thus c-jun and junD act as general positive regulators whereas junB acts as a general suppressor of epidermal-specific genes. Therefore, the differentiation specificity of the AP1 regulation must be determined not only by the formation of distinct DNA/AP1 complexes but also by interactions involving other transcriptional regulators and/or distal regulatory elements.

Self-monitored exercise at three different RPE intensities in treadmill vs field running.

The aims of the present study were a) to compare the outcome of running exercise performed on a treadmill (laboratory) and an outdoor track (field) using an RPE production protocol and b) to study this kind of protocol used over time (3-5 wk). A group of 11 healthy male subjects participated, with ages varying from 33 to 65 yr (mean = 42.9 +/- 11.0 yr). Two test sessions consisting of both treadmill and track exercise were performed in a rotated order to control for sequential effects. All subjects exercised according to an identical protocol: two successive trials (3 min each) at RPE 11 (light exertion), followed by a RPE 13 (somewhat hard) trial (11 min) and, finally, a RPE 15 (hard) trial (5 min). Results show significantly different levels of heart rate (HR), blood lactate, and velocity at the three RPE levels. Large differences were also observed in all measured variables between field and laboratory. These differences were consistent over time. A high internal consistency, measured by test-retest reliability (alpha greater than 0.9), was obtained for both velocity and HR between the first two trials at RPE 11. In conclusion, the RPE method functioned well as a means of monitoring and regulating exercise intensity.

A category-ratio perceived exertion scale: relationship to blood and muscle lactates and heart rate.

The purpose of this investigation was to study the relationship between perceptual ratings from Borg's new category-ratio scale and some physiological variables during exercise. To accomplish this, scale ratings were related to blood and muscle lactate accumulation and heart rates during a progressive, maximal exercise test on the cycle ergometer. Ten physically active males were utilized as subjects; lactate data were recorded on only 7 of the 10 subjects. Three ratings of perceived exertion were made at each stage of the exercise test: leg effort (LE), cardiorespiratory effort (CE), and leg pain (LP). All ratings showed a positively accelerating increase with exercise intensity as did both blood and muscle lactate, while heart rate increased linearly. The exponents of the power functions describing the perceptual variation ranged from 1.63-1.67 compared to 2.2 for blood lactate and 2.7 for muscle lactate. Polynomial analysis revealed a similar quadratic trend for both perceptual and blood lactate data; however, muscle lactate demonstrated a cubic trend. No significant differences were found between CE and LE at 100, 200, and 300 W (P greater than 0.05). Subjects with the highest percentage of slow-twitch muscle fibers (mean ST%=51.14) rated LE and CE significantly lower ( mean of all power outputs, 0-300 W) than those with the lowest ST% (mean=34.52). It is concluded that the ratings from the category-ratio scale correspond very well with glycogenolytic metabolism leading to lactate accumulation during exercise.

Identification of 17 novel mutations in 40 Argentinean unrelated families with mucopolysaccharidosis type II (Hunter syndrome).

Mucopolysaccharidosis type II (MPSII) is an X-linked lysosomal storage disorder caused by deficiency of the enzyme iduronate-2-sulfatase (IDS). The human IDS gene is located in chromosome Xq28. This is the first report of genotype and phenotype characterization of 49 Hunter patients from 40 families of Argentina. Thirty different alleles have been identified, and 57% were novel. The frequency of de novo mutations was 10%. Overall, the percentage of private mutations in our series was 75%.

Exercise-induced oxidative stress in elderly subjects: the effect of red orange supplementation on the biochemical and cellular response to a single bout of intense physical activity.

Aging is characterized by an impaired capacity to maintain the redox balance both in physiological and pathological situations associated with an increased production of reactive oxygen species. Since the extent of this phenomenon may be influenced by an antioxidants-rich diet, we investigated the effect of supplementation with fresh red orange juice (ROJ) on biochemical and cellular biomarkers of oxidative stress in healthy, trained elderly women after a single bout of exhaustive exercise (EE). To this purpose, a sample of 22 females, 15 (69.0 ± 5.1 years) taking the ROJ supplementation and 7 (68.1 ± 2.7 years) as Control group, was constituted. Blood samples were collected immediately before, 30 minutes, and 24 hr after a single bout of EE, at baseline and after 4 weeks. Our results demonstrate that markers of DNA damage or apoptosis were not affected by EE both in Control and ROJ group, and by ROJ, whereas, exercise temporarily affected the redox balance in both groups. Controls didn't change their response to EE after the experimental period, but experimental group after ROJ supplementation had lower EE-induced MDA, consumed less ascorbic acid, and had less activation of the hypoxanthine/xanthine system, i.e., they seemed to be protected from hypoxia/reoxygenation mechanisms.

Expressão do Mg+2, CK, AST e LDH em equinos finalistas de provas de enduro / Endurance horses finalists: expression of Mg+2, CK, AST and LDH in horse finalists of endurance race

Nos últimos anos, o equino atleta vem sendo cada vez mais requerido. Dessa forma, as exigências por alto desempenho têm fomentado o interesse pelo estudo das afecções relacionadas com a fisiopatologia de diversas enfermidades dos equinos. A relação entre o íon magnésio e o exercício físico tem recebido atenção significativa visto que este íon está intimamente relacionado ao tecido muscular estriado esquelético. Além disso, dentre as principais estratégias para a detecção e acompanhamento clínico de lesões musculares, destacam-se a avaliação das atividades das enzimas creatino quinase (CK), lactato desidrogenase (LDH) e aspartato aminotransferase (AST). A busca pelo estabelecimento de parâmetros que se relacionam entre si é um fator determinante na compreensão de alterações fisiológicas encontradas diante do esforço em equinos atletas. Desta forma, o presente trabalho teve como objetivo determinar como as concentrações sanguíneas do íon magnésio e as atividades enzimáticas das enzimas CK, LDH e AST comportaram-se em equinos Puro Sangue Árabe finalistas de provas de enduro de 90km e relacionar as possíveis alterações com o tipo de esforço físico desempenhado pelos animais. Foram avaliadas a atividade enzimática das enzimas CK, LDH, AST e a concentração do íon magnésio no exercício em relação ao repouso de 14 equinos clinicamente hígidos da raça Puro Sangue Árabe, sendo 9 machos e 5 fêmeas, com idades variando entre 6 a 12 anos, submetidos a treinamento para enduro e participantes de provas de 90 km. Pode-se observar que as variáveis acima mencionadas sofreram aumento com diferença estatística em relação ao repouso. O exercício físico de enduro determinou a ocorrência de alterações nas atividades enzimáticas das enzimas CK (p≤0,001), LDH (p=0,0001), AST (p=0,0007) e na concentração do íon magnésio (p=0,0004), no exercício em relação ao repouso (p≤0,05). Fato que determinou alteração de permeabilidade das células musculares estriadas esqueléticas, sugerindo o estabelecimento de um processo inflamatório agudo. Devido à expressão da atividade enzimática da CK (p≤0,001), por sua especificidade em relação à ocorrência de danos na musculatura estriada esquelética, juntamente com o íon magnésio (p=0,0004) que participa de várias reações celulares. Houve alterações na concentração de proteína plasmática total (p=0,0009) e hematócrito (p=0,0001), entre os momentos avaliados. Portanto estes resultados servem como valores de referência de equinos finalistas de provas de enduro de 90 km, auxiliando na prevenção da ocorrência de possíveis danos musculares e processos inflamatórios severos.

In recent years, due to rising competitive demands, the equine athlete is being increasingly required. Thus, the demands for high performance have fostered interest in the study of pathophysiology of various horse diseases. The relationship between magnesium and exercise has received significant attention because this ion is closely related with the skeletal muscle tissue. Moreover, among the main strategies for the detection and monitoring of clinical muscle damage, features the evaluation of the activity of the enzymes creatine kinase (CK), lactate dehydrogenase (LDH) and aspartate aminotransferase (AST). The search for the establishment of parameters that relate to each other is a determining factor in understanding the physiological changes found on athletic horses in effort. Thus, this study aimed to determine how the blood concentrations of magnesium ion and the enzymatic activities of the enzymes CK, LDH and AST behave in Arabian finalist horses in endurance races of 90km and to relate possible changes to the type of physical effort played by animals. It was evaluated the enzymatic activities of the enzymes CK, LDH, AST e the concentration of the ion magnesium in exercise in relation to the rest state of 14 clinically healthy Arabian horses, 9 males and 5 females, with ages ranging from 6 to 12 years, undergoing endurance training and participants in 90 km distance rides. All variables evaluated had an increase with statistical differences in relation to rest. The physical endurance exercise determined the occurrence of changes in enzyme activities of CK (p≤0.001), LDH (p=0.0001), AST (p=0.0007) and in the concentration of magnesium ion (p=0.0004), in exercise in relation to rest (p≤0.05). Fact that determined changes in permeability of striated skeletal muscle cells, suggesting the establishment of an acute inflammatory process. Mainly due to the expression of enzymatic activity of CK (p≤0.001), for its specificity in relation to the damage to skeletal striated muscles, along with the magnesium ion (p=0.0004) that actively acts in various cellular reactions. There were changes in total plasma protein concentrations (p=0.0009) and hematocrit (p=0.0001), between the evaluated moments. Therefore, these results serve as a reference of support equine finalists in an endurance race of 90 km, aiding in the prevention of the occurrence muscle damage and severe inflammatory processes.

Osmolaridade, ânion gap, potencial hidrogeniônico e íons plasmáticos mensuráveis de equinos puro sangue Árabe finalistas em provas de enduro de 90 km / Osmolality, anion gap, percentage Hydrogen (pH) and the mesasurable plasma ions in purebred arabian horses which were finalists in 90km endurance races

Foi avaliado o comportamento da osmolaridade, do ânion gap, do pH e dos íons plasmáticos mensuráveis de 14 equinos, 9 machos e 5 fêmeas, Puro Sangue Árabe finalistas em provas de enduro de 90 km. Para tanto, foram colhidas em dois momentos (repouso e após o exercício prolongado) amostras de sangue venoso para a mensuração dessas variáveis. Pode-se verificar, a partir do repouso, aumento significativo dos valores do Hct, das PPT e do AG, sugerindo perda de fluidos e discreto grau de desidratação. O pH e o íon H+ quase não se alteraram, indicando ausência de distúrbios metabólicos. Reduções com diferenças significativas foram observadas para os íons Cl-, HCO3-, K+, Ca++, assim como do EB. Pode-se então, sugerir que o tipo de exercício a que os animais foram submetidos foi compatível com a capacidade atlética e ainda que a suplementação durante a competição contribuísse para minimizar tais perdas.

We evaluated the behavior of osmolality, anion gap, pH and measurable plasma ions of 14 Purebred Arabian horses, 9 males and 5 females, finalists in an endurance race of 90 km. In order to achieve this, we collected venous blood samples twice, at rest and after prolonged exercise, in order to measure the interest variables. The results allowed to observe that from the rest an increase with significant difference in the values of Hct, PPT and AG, suggesting loss of fluids and slight dehydration. The pH and the H+ ion almost had no changes, indicating absence of metabolic disorders. Reductions, with significant difference, were verified for the ions Cl-, HCO³-, K+, Ca++, as well as BE. These data suggest that the type of exercise to which the animals were submitted was consistent with the athletic ability and that supplementation during the competition contributed to minimize such losses.

Prolonged exercise at a constant load on a bicycle ergometer: ratings of perceived exertion and leg aches and pain as well as measurements of blood lactate accumulation and heart rate.

To study changes over time during prolonged exercise on a bicycle ergometer at a constant load, 22 healthy males rated perceived exertion as well as aches and pain in the legs, and measurements were taken on blood lactate accumulation and heart rate (HR). The prolonged exercise was carried out at WOBLA (the power level eliciting a blood lactate concentration of 4 mmol X l-1). All four measured variables, ratings of perceived exertion, ratings of aches and pain in the legs, blood lactate accumulation, and HR, grew systematically according to negatively accelerating functions. HR showed more of a steady state, whereas all the other three variables grew continuously over time. Three subgroups were identified related to the blood lactate response after 15 min at WOBLA: elevated (greater than 5 mmol X l-1), intermediate (3.5-4.9 mmol X l-1), and low (less than 3.4 mmol X l-1). It was suggested that a major contribution to the discrepancies in blood lactate between the subgroups after 15 min was partly due to insufficient warming up, which was 5 min at 20 W as compared with the final power level (WOBLA), which differed between 140 and 260 W. After 15 min both rated perceived exertion and rated aches and pain in the legs were related to the corresponding blood lactates. It was suggested that rated perceived exertion and rated aches and pain in the legs partly reflected the degree of "anaerobic" metabolism measured as blood lactate.

Exercise for older women: a training method and its influences on physical and cognitive performance.

The decline in physical and mental ability often associated with increasing age in adults has both social and economic implications that affect most nations. Hence, the maintenance of functional capacity and independence of the older person are beneficial both for the individual and society alike. One way to enhance functioning in old age is physical exercise. However, few methods exist that enable older people to monitor and regulate exercise intensity without using expensive apparatus. Utilizing the individual's subjective feeling of perceived exertion through the use of a simple rating scale is an approach that differs markedly from those previously employed. The present study used the ratings of perceived exertion (RPE) scale to induce different exercise intensities in groups of older women. Walking was chosen as the type of exercise since most older women are unfamiliar with, or afraid to engage in, other types of physical exercise such as bicycling or running. Results indicated that physical exercise capacity increased after 3 months of regular low-intensity walking in the exercise groups but not in nonexercising controls. Furthermore, these changes were accompanied by improved digit span performance. In conclusion, this study has shown that the RPE scale may be used for exercise regulation and that older women would seem to be able to use the scale to monitor and regulate their exercise intensity in an outdoor environment in much the same way as younger individuals.

The increase of perceived exertion, aches and pain in the legs, heart rate and blood lactate during exercise on a bicycle ergometer.

This study was designed to show the general increase in perceived exertion, perception of aches or pain in the legs, heart rate (HR), and blood lactate, and the covariance between these variables during bicycle ergometer work, and to describe individual differences both within and between power levels by testing a large group (28 male students). Estimates of perceived exertion and feelings of aches or pain in the legs were recorded using Borg's category-ratio scale (CR-10). The subjects were tested with a stepwise increase of power levels with 40 W increments up to a voluntary maximum. Though HR increases fairly linearly with power, the other variables follow positively accelerating functions with exponents of about 1.6-2 for the perceptual variables, and an exponent of about 3 for blood lactate. The results from the 8 most fit subjects could be described in the same way as for the whole group except for blood lactate, where there was a need to include a threshold value (b), that, together with a rest value (a), shows the starting point of the function (R = a + c(W - Wo)n). The data support the idea that a combination of heart rate and blood lactate is a better predictor of perceived exertion and feelings of aches and pain in the legs, than is each of the single physiological variables taken alone.