Relación entre la capacidad cardiovascular y la capacidad de esprints repetidos en árbitros de fútbol de alto nivel

Los objetivos de este estudio fueron por un lado, describir el rendimiento en una prueba de rendimiento cardiovascular realizada en laboratorio y en otra de esprints repetidos (RSA) en árbitros de fútbol de alto nivel, y por otro lado, analizar la asociación entre los resultados obtenidos en ambas pruebas. Doce árbitros de fútbol de alto nivel (Divisiones 1ª, 2ª y 2ª B, 28,8±5,1 años, 73,2±6,6 kg, 1,8±0,1 m 22,82±1,38 kg·m-2) participaron en el estudio. Los árbitros obtuvieron un consumo máximo de oxígeno (VO2max) de 59,50±4,56ml·kg-1·min-1. El tiempo medio de los esprints repetidos (RSAMedia) en 15 y 30 m fue de 2,54±0,09 s y 4,43±0,14 s, respectivamente, tardando 15,26±0,53 s y 26,60±0,82 s en completar los seis esprints (RSATotal). Los índices de fatiga en 15 y 30 m fueron de 2,25±1,05% y 3,33±1,59% (RSASdec) y de 3,45±2,92% y 6,31±4,63% (RSACambio).Se obtuvieron asociaciones positivas entre distintas variables cardiovasculares y de tiempo en RSA. Por el contrario, el consumo de oxígeno en las intensidades de umbral ventilarorio 1 (VT1) y  umbral ventilatorio 2 (VT2) correlacionó negativamente con el índice de fatiga RSASdec.Una mayor capacidad cardiovascular en árbitros de fútbol, a pesar de poder producir un efecto negativo sobre el tiempo empleado en el RSA, puede minimizar la fatiga durante los esprints repetidos.

Jump landing characteristics in elite soccer players with cerebral palsy

The aim of the present study was to analyse the parameters that characterize the vertical ground reaction force during the landing phase of a jump, and to determine the relationship among these parameters in elite soccer players with cerebral palsy (CP). Thirteen male members of the Spanish national soccer team for people with CP (mean age: 27.1 ± 4.7 years) volunteered for the study. Each participant performed three counter movement jumps. The characteristics of the first peak of the vertical ground reaction force during the landing phase of a jump, which corresponds to the forefoot contact with the ground, were similar to the results obtained in previous studies. However, a higher magnitude of rearfoot contact with the ground (F2) was observed in participants with CP than in participants without CP. Furthermore, a significant correlation between F2 magnitude and the elapsed time until its production (T2) was not observed (r = -0.474 for p = 0.102). This result implies that a landing technique based on a delay in the production of F2 might not be effective to reduce its magnitude, contrary to what has been observed in participants without CP. The absence of a significant correlation between these two parameters in the present study, and the high magnitude of F2, suggest that elite soccer players with CP should use footwear with proper cushioning characteristics.

Inactivation of phosphoglycerate mutase and creatine kinase isoenzymes in human serum

AIMS/BACKGROUND

Total phosphoglycerate mutase (PGM) activity in serum has been shown to be increased in acute myocardial infarction with the same time course as creatine kinase (CK) activity. However, the increase in the muscle (MM) and in the cardiac (MB) PGM isoenzymes was not as high as expected. The present study was undertaken to characterise PGM inactivation by serum and to compare it with serum CK inactivation.

METHODS

The PGM and the CK activities of extracts of human heart, skeletal muscle, and brain were determined spectrophotometrically after incubation with different media, namely: plasma, whole serum, dialysed serum, heated serum, serum ultrafiltrate, urate solution, and buffer solution.

RESULTS

Type MM PGM was inactivated by plasma, whole serum, heated serum, dialysed serum, and serum ultrafiltrate. Inactivation in dialysed serum was reduced by EDTA and largely reversed by thiol agents. Inactivation in serum ultrafiltrate was not prevented by EDTA and only partially reversed by dithiothreitol. The muscle and type BB CK isoenzymes were inactivated in all the tested media. The incubation of human and rabbit skeletal muscle PGM and CK in urate solution showed that urate does not affect mutase activity under conditions that inactivate CK.

CONCLUSIONS

These results confirm the mechanisms of CK inactivation proposed by others and show that the type M PGM subunit is inactivated by two different mechanisms, which appear to involve the thiol groups of the enzyme. One mechanism is caused by either a protein component or a protein bound serum component and involves calcium ions and/or another chelatable metal ion. The other mechanism is caused by a lower molecular weight serum component and is metal ion independent.

S-Adenosylmethionine modulates inducible nitric oxide synthase gene expression in rat liver and isolated hepatocytes

BACKGROUND/AIMS

Hepatocellular availability of S-adenosylmethionine, the principal biological methyl donor, is compromised in situations of liver damage. S-Adenosylmethionine administration alleviates experimental liver injury and increases survival in cirrhotic patients. The mechanisms behind these beneficial effects of S-adenosylmethionine are not completely known. An inflammatory component is common to many of the pathological conditions in which S-adenosylmethionine grants protection to the liver. This notion led us to study the effect of S-adenosylmethionine administration on hepatic nitric oxide synthase-2 induction in response to bacterial lipopolysaccharide and proinflammatory cytokines.

METHODS

The effect of S-adenosylmethionine on nitric oxide synthase-2 expression was assessed in rats challenged with bacterial lipopolysaccharide and in isolated rat hepatocytes treated with proinflammatory cytokines. Interactions between S-adenosylmethionine and cytokines on nuclear factor kappa B activation and nitric oxide synthase-2 promoter transactivation were studied in isolated rat hepatocytes and HepG2 cells, respectively.

RESULTS

S-Adenosylmethionine attenuated the induction of nitric oxide synthase-2 in the liver of lipopolysaccharide-treated rats and in cytokine-treated hepatocytes. S-Adenosylmethionine accelerated the resynthesis of inhibitor kappa B alpha, blunted the activation of nuclear factor kappa B and reduced the transactivation of nitric oxide synthase-2 promoter.

CONCLUSIONS

Our findings indicate that the hepatoprotective actions of S-adenosylmethionine may be mediated in part through the modulation of nitric oxide production.

Efficacy and safety of metamizol vs. acetylsalicylic acid in patients with moderate episodic tension-type headache: a randomized, double-blind, placebo- and active-controlled, multicentre study

We assessed the efficacy and safety of oral single doses of 0.5 and 1 g metamizol vs. 1 g acetylsalicylic acid (ASA) in 417 patients with moderate episodic tension-type headache included in a randomized, double-blind, placebo- and active-controlled, parallel, multicentre trial. Eligibility criteria included 18-65 years of age, history of at least two episodes of tension-type headache per month in the 3 months prior to enrollment, and successful previous pain relief with a non-opioid analgesic. Treatment arms were metamizol 0.5 g (n = 102), metamizol 1 g (n = 108), ASA 1 g (n = 102) and placebo (n = 105). The analgesic efficacy of 0.5 and 1 g metamizol vs. placebo was highly statistically significant (alpha: 0.025; one-sided) for sum of pain intensity differences, maximum pain intensity difference, number of patients with at least 50% pain reduction, time to 50% pain reduction, maximum pain relief and total pain relief. A trend towards an earlier onset of a more profound pain relief of 0.5 and 1 g metamizol over 1 g ASA was noticed. All medications including placebo were almost equally safe and well tolerated.

Efficacy and safety of dipyrone versus tramadol in the management of pain after hysterectomy: a randomized, double-blind, multicenter study

BACKGROUND AND OBJECTIVES

We assessed the efficacy and safety of dipyrone in comparison with tramadol in the relief of early postoperative pain following abdominal hysterectomy.

METHODS

A total of 151 women between 18 and 60 years of age undergoing abdominal hysterectomy during general anesthesia participated in a randomized, double-blind, controlled, multicenter study. Seventy-three patients received dipyrone and 78 received tramadol. Patients received an intravenous loading dose of the study drug immediately after operation followed by intravenous (IV) maintenance infusion and IV on-demand boluses up to a maximum number of predetermined doses/day of 8 g dipyrone and 500 mg tramadol. The duration of the study was 24 hours.

RESULTS

The mean (SD) number of boluses in the dipyrone group was 3.8 (2.4) and 3.5 (2.5) in the tramadol group (95% confidence interval, -0.455 to 1.175), and the percentage of patients requiring rescue IV morphine (dipyrone 26.9%, tramadol 26.8%) was not statistically significant. Other analgesic efficacy parameters, such as pain intensity differences, sum of pain intensity differences, pain relief assessed by the patient, or patients who required the maximum number of demand doses, were not different between treatment groups. A significantly higher percentage of adverse gastrointestinal effects was found in patients given tramadol (42.1%) than in patients given dipyrone (20.2%) (P <.05). Also, a significantly higher number of tramadol-treated patients required ondansetron to control nausea and vomiting at 1 hour (19% v 7%), 2 hours (26% v 11%), and 24 hours (46% v 29%) (P <.05) after surgery. Patients and the investigators reported similar tolerability for both study arms.

CONCLUSIONS

Dipyrone and tramadol showed similar efficacy for early pain relief after abdominal hysterectomy. Nausea and vomiting, possibly caused by the tramadol, occurred more frequently in those patients. In this group, the need of the antiemetic drug ondansetron was also higher.

S-adenosylmethionine in alcoholic liver cirrhosis: a randomized, placebo-controlled, double-blind, multicenter clinical trial

BACKGROUND/AIM

The efficacy of S-adenosylmethionine (AdoMet) in the treatment of liver cell injury has been demonstrated in several experimental models. The aim of this study was to investigate the effects of AdoMet treatment in human alcoholic liver cirrhosis.

METHODS

A randomized, double-blind trial was performed in 123 patients treated with AdoMet (1200 mg/day, orally) or placebo for 2 years. All patients had alcoholic cirrhosis, and histologic confirmation of the diagnosis was available in 84% of the cases. Seventy-five patients were in Child class A, 40 in class B, and 8 in class C. Sixty-two patients received AdoMet and 61 received placebo.

RESULTS

At inclusion into the trial no significant differences were observed between the two groups with respect to sex, age, previous episodes of major complications of cirrhosis, Child classification and liver function tests. The overall mortality/liver transplantation at the end of the trial decreased from 30% in the placebo group to 16% in the AdoMet group, although the difference was not statistically significant (p = 0.077). When patients in Child C class were excluded from the analysis, the overall mortality/liver transplantation was significantly greater in the placebo group than in the AdoMet group (29% vs. 12%, p = 0.025), and differences between the two groups in the 2-year survival curves (defined as the time to death or liver transplantation) were also statistically significant (p = 0.046).

CONCLUSIONS

The present results indicate that long-term treatment with AdoMet may improve survival or delay liver transplantation in patients with alcoholic liver cirrhosis, especially in those with less advanced liver disease.

Metabolic labelling and partial characterization of glycophospholipids in pancreatic islet cells

Insulin action is thought to be mediated by an inositol-, glucosamine- and galactose-containing oligosaccharide liberated by phosphodiesterase hydrolysis of a glycosyl-phosphatidylinositol. This oligosaccharide inhibits insulin biosynthesis and secretion in pancreatic islets. In the present study, two main glycolipids (peak I and II) were resolved by sequential TLC of lipids extracted from islet cells labelled with tritiated glucosamine, galactose or myristate. The two glycolipids displayed comparable sensitivity to beta-galactosidase but differed from one another by their sensitivity to phosphatidylinositol-specific phospholipase C. Moreover, structural heterogeneity within each peak was suggested by their partial resistance to nitrous acid deamination. These findings support the presence in islet cells of glycolipids similar to those currently considered as a possible postreceptor target for insulin in other cell types.