Melatonin administrated immediately before an intense exercise reverses oxidative stress, improves immunological defenses and lipid metabolism in football players.

Acute sport exercise leads to a strong stimulation of muscle tissue and a change in the organism energy demands. This study was designed to investigate the effect of oral melatonin supplementation on human physiological functions associated with acute exercise. Immune, endocrine and metabolic parameters were measured in 16 young male football players, who were divided into two groups, an experimental group (supplementation with 6 mg of melatonin administered 30 min prior to exercise) and a control group (placebo without melatonin). They performed a continuous exercise of high intensity (135 beats/min). Samples were collected 30 min before the exercise and 3, 15 and 60 min during the exercise. The results indicated that the acute sport training presented: a) increased lipid peroxidation products (MDA) in both groups, control and experimental, with levels significantly decreased in the group treated with melatonin after 15 and 60 min of high-intensity exercise, b) the total antioxidant activity (TAS) was lower in the control group than in the experimental, the latter showing significant differences at 60 min of high-intensity exercise c) the lipid profile of subjects in the experimental group showed lower triglyceride levels than the control group after 15 and 60 min of high-intensity exercise, d) immunological studies only showed, in the experimental group, an increase in IgA levels at 60 min after the exercise, and finally there were no significant differences between the groups for any of the other variables. In conclusion these results indicated that treatment with melatonin in acute sports exercise reversed oxidative stress, improved defenses and lipid metabolism, which would result in an improvement in fitness.

[Reliability index of anorectal manometry for the diagnosis of Hirschspurng disease]. / Indices de fiabilidad de la manometría anorrectal para el diagnóstico de la enfermedad de Hirschsprung en cualquier edad.

UNLABELLED: The anorectal manometry (AM) and suction rectal biopsy (BS) are the main and accepted methods for diagnosis of Hirschsprung disease (HD). The reliability of these methods in newborns have been subject of controversy up to the present. MATERIAL AND METHODS: For diagnosis of HD purpose we have performed 2227 AM records in 1744 children. Initially we used a minichamber type probe joined to a close system to perform AM. From 1984 we developed a new type of 4 ways miniprobe connected to an open system which improved the reliability of the records. RESULTS: The indexes of reliability for our database have been the following: sensitivity 98%, specificity 97%, positive predictive value 85%, negative predictive value 99%, false positive 3.4% and false negative 1.8%. CONCLUSIONS: AM is a non invasive method with a high reliability, available in our hospital. It is a choice method for diagnosis of HD.

[Central chemoreceptors and sudden infant death syndrome]. / Quimiorreceptores centrales y síndrome de muerte súbita del lactante.

INTRODUCTION: Carbon dioxide partial pressure and pH in the extracellular compartment are the most powerful signals regulating respiration. Central chemoreceptors (QC) undergo the stimulating effect of CO2 and pH upon respiration. AIMS: This review tries to provide an actual envision of the progress in the knowledgement on central chemoreception. It also tries to highlight the importance of the alterations in the chemoreception mechanism as a cause of sudden infant death syndrome (SIDS). DEVELOPMENT: Central chemoreceptors respond to acid-base imbalance acting on neurons that give rise to the central breathing pattern and have the ability to change the respiratory rate, which is normally needed to restore the normal values of acid-base status. QC are widely distributed in the brain stem, however QC neurons in the ventral surface of the medulla like to be the main relays for ventilatory responses after acid-base stimulation. CONCLUSIONS: It has been shown that QC are sensitive to pH and CO2 as in vivo as in vitro conditions, most of them being serotonin immunopositive, a neurotransmitter with known effects on breathing pattern. By other side, alterations of central chemoreception have been associated to pathologies like congenital hypoventilatory syndrome or SIDS. Interestingly, the post mortem exams of the brain of infants dead because these syndromes have showed anomalies of serotonergic receptor located in regions containing QC neurons and in others related with cardiorespiratory integration.

[Effects of water diuresis on the urinary ph of patients under relapsing lithiasis]. / Efectos de la diuresis acuosa sobre el pH urinario de los pacientes litiásicos recidivantes.

INTRODUCTION: It has been observed that in healthy individuals the increase in urinary flow induced by water overload may be enough to alter the urinary Ph to obtain values considered safe in the prophylaxis of lithogenesis. The aim of the present paper is to determine the effects of water diuresis on the urinary Ph of patients suffering from relapsing lithiasis. MATERIAL AND METHOD: 26 patients were included in the present study. The urinary Ph of all patients was measured along two consecutive days, at 8.30 and again at 12.30, under normal conditions (the first day) and once they had received a water load equivalent to 1.5% of their weight (the second day). RESULTS: The altered mean value of the Ph induced on the first day by the circadian rhythm showed a mean of 0.13 units of Ph, which lacks statistical significance (p > 0.05). However, on the second day we obtained a value of 0.42, which is statistically significant (p < 0.01). The normal tendency after the water overload was towards a positive increase of the Ph in those patients whose urine showed a preload Ph value < 6.1, whereas those individuals with a preload Ph value > 6.48 suffered negative increases. CONCLUSIONS: The increase of diuresis induced by water load proved enough to provoke an increase of urinary Ph when its baseline value is < 6.1, or either a decrease when its baseline value is > 6.48. In both cases, Ph values ranged between 6-6.5 which are considered safe values in the prophylaxis of lithogenesis. The more separated the baseline urinary Ph is from the 6.1-6.48 range, the greater the effect of the water load.

[Aqueous diuresis and prophylaxis of recurrent nephrolithiasis]. / Diuresis acuosa y profilaxis de la nefrolitiasis recidivante.

Crystal precipitation in urine results from factors such as ionic strength, pH, soluble complexes formation, formation site and retention of initial solid particle. Among the most frequent causes are poor diuresis and changes in urine pH, their influence being quantified in different ways. Effects of water diuresis such as prophylaxis for urinary calculi are due to the intrinsic properties of the water contained in the urine, solid particles dragging, action on urine infection and changes in urine pH. Urinary flow has an influence on pH, so that its decrease coincides with concentrate urine and low pH, whereas its increase involves the presence of dilute urine and high pH. The purpose of this study is to understand the relationship between increased urine volume due to greater water intake and changes in urine pH, as well as the physiological intervening mechanisms.

[Relationships between diuresis, urine pH and lithogenesis]. / Relaciones entre diuresis, pH de la orina y litogénesis.

Although an increased water intake is suitable in the pathophysiology and treatment of renal lithiasis, less attention is given to changes caused by water diuresis on urinary pH. The objective of this study was to show the relationship between urinary flow and pH. On two consecutive days, at the beginning and end of a four-hour interval starting at 8:00 am, volume and pH in urine, as well as plasma osmolality, haematocrit and protein concentrations were measured; all specimens were collected under normal conditions except for those collected on the second day at noon, which were collected after a water load equivalent to 1.5% body weight taken between 8:00 and 9:00 am. A decrease in serum osmolality, haematocrit and protein concentrations was noted. Urinary pH changes were different based on baseline values. Baseline urine pH values lower than or equal to 5.8 resulted in increased values, while baseline values greater than or equal to 6.5 gave decreased values. Mean increase in pH as a result of greater water intake was 0.57 units.