A comparative study of blood lactate tests in swimming

Three different modes of lactate tests were studied. Eleven male competitive swimmers performed the tests (n.100 m, n.300 m, 2.100m + 2.400 m) within 5 days. Swimming velocity (V) vs blood lactate (BLa) and V vs heart rate (HR) curves were averaged. In V vs BLa comparisons, the BLa values of 4 mmol.l-1 in 2.400 m, 3 mmol.l-1 in n.300 m, and 2 mmol.l-1 in n.100 m modes were found to correspond to the same V. Although the resting BLa values were similar before the testing occasions, the initial BLa value in very easy swimming was lower in the n.300 m than in the n.100 m mode. The elimination of lactate most probably caused this difference. The highest BLa value was measured in the n.100 m (14.9 mmol.l-1) and 2.100 m (13.6 mmol.l-1) exercise modes demonstrating a higher rate of anaerobic energy production than in the n.300 m or 2.400 m test modes. In HR vs V comparison, the n.300 m and 2.400 m modes demonstrated similar HR values in relation to V. To measure the whole intensity area, a combination of tests should be applied by performing an incremental set with several steady-state loadings (aerobic) and one or two 100 m swims (anaerobic) in one test session.     

Responses of serum androgenic-anabolic and catabolic hormones to prolonged strength training

Endocrine and neuromuscular effects of prolonged strength training were investigated in 21 strength-trained male subjects during the course of a 24-week progressive strength training and during a subsequent detraining period of 12 weeks. Maximal isometric leg extensor force increased by 19% (P less than 0.001) during the first 20 weeks, followed by a plateau during the 4 latest weeks of training. During the course of the training period, no systematic change was found in serum testosterone concentrations, but there was a decreasing tendency in the concentrations of free testosterone (NS), 17-OH-progesterone (NS), androstenedione (P less than 0.05), dehydroepiandrosterone (P less than 0.05), cortisol (P less than 0.01), transcortin (CBG) (P less than 0.05), and in the cortisol/CBG ratio (P less than 0.05). The last 4 weeks of training were characterized by significant correlations between the individual changes in maximal isometric force and the changes in serum free testosterone concentrations (r = 0.60, P less than 0.01). The changes in the ratios of free testosterone to cortisol (r = 0.73, P less than 0.001), total testosterone to cortisol (r = 0.83, P less than 0.001), and 17-OH-progresterone to cortisol (r = 0.62, P less than 0.01) also correlated with the changes in maximal force. The findings suggest that the turnover of endogenous androgens may increase during progressively intensified training without a change in serum total testosterone concentration. Prolonged intensive strength training may also lead to changes in the concentrations of serum cortisol and transcortin. During the most stressful phases of training, the changes in serum androgen/cortisol ratios seem to be highly individual and may correlate with changes in muscular strength.     

A new method of total parenteral nutrition for surgical neonates: it is possible that cyclic TPN prevents intrahepatic cholestasis

Cholestasis associated with total parenteral nutrition (TPN) has been reported to be an incidence of 15% to 50% in surgical neonates. This study was designed to prevent the liver dysfunction, especially intrahepatic cholestasis, caused by TPN for surgical neonates. In the last three years, 10 surgical neonates ranged from 1868g to 3500g of birth weight have been treated by cyclic TPN that infuses solutions of TPN and Non-TPN alternately every four hours, because cyclic TPN may reduce an overloading for the liver by the compulsive and continuous TPN. Consequently, no hyperbilirubinemia and abnormal values of the serum transaminases were revealed in these neonates, and good results of nutritional supports were obtained by cyclic TPN. These results suggest that cyclic TPN is useful and safe in nutritional support for neonates, and cyclic TPN is much better than continuous TPN in order to prevent the liver dysfunction.     

Case report of an anomalous arrangement of the pancreaticobiliary ducts and nuclear DNA ploidy analysis

Two cases with an anomalous arrangement of the pancreaticobiliary ducts (APBD) are reported in order to investigate the mechanism of carcinogenesis of the extrahepatic biliary tract from the aspect of DNA ploidy analysis. Highly elevated biliary enzymes were found in both cases. Although inflammatory changes without any metaplasia or neoplasia were observed histologically, a cytofluorometric nuclear DNA ploidy analysis showed an aneuploid low ploidy pattern in a histogram of the gall bladder, an aneuploid high ploidy pattern in a histogram of the common bile duct in one patient, and a diploidy pattern in the gall bladder, an aneuploid low pattern in the common bile duct in another case. These results may show that APBD may play a role in the development in DNA ploidy abnormality with refluxed pancreatic juice which may induce repeated irritation and inflammation. Radical surgery including a complete excision of the extrahepatic biliary tract followed by reconstruction may achieve better results with regard to undesirable consequences with an abnormal nuclear DNA ploidy pattern and decrease the likelihood of developing carcinoma.     

Effects of cholecystokinin-octapeptide and tetragastrin on the contractile activities of the stomach, duodenum and papilla of Vater

Effects of cholecystokinin-octapeptide (CCK-OP) and tetragastrin (TG) on the stomach, duodenum and papilla of Vater were examined using 13 adult dogs. The contractile activities of the stomach and duodenum were examined using the strain gage, and the manometric study of the papilla of Vater was also performed. CCK-OP increased the contractile activities of the stomach and duodenum, but at the same time the pressure of the papilla of Vater was decreased. TG increased the contractile activities of the stomach, but decreased that of the duodenum and the pressure of papilla of Vater. CCK-OP lowered the pressure of the common bile duct, and that fall corresponded with the disappearance of the phasic contraction of the papilla of Vater. We concluded that the contractile activity of the papilla of Vater was independent of the contractile activity of the duodenum, and the most effective drainage of the bile was achieved at the time of the disappearance of the phasic contraction of the papilla of Vater.     

Effects of prestretch intensity on mechanical efficiency of positive work and on elastic behavior of skeletal muscle in stretch-shortening cycle exercise

Mechanical efficiency of positive work (eta+) and elastic behavior of human skeletal muscles were investigated on a special sledge apparatus which allowed the use of the normal stretch-shortening cycle exercises. Twenty-five young men were investigated in a total of 92 exercise situations, in which the intensity of the prestretch (eccentric contraction) was different, but the shortening phase (concentric contraction) was kept constant in all conditions. The results demonstrated that eta+ was on the average 35.8% +/- 6.4% and correlated positively with the prestretch intensity (r = 0.413; P less than 0.001), reaching a highest individual value of 51.5%. Estimation performed on the elastic characteristics of the leg extensor muscles confirmed an earlier suggestion that the pure muscle elasticity plays an important role in potentiating performance in stretch-shortening cycle exercises. The analysis of the myoelectrical activity of the leg extensor muscles showed that the nervous system plays an essential role in regulating muscle stiffness and thus utilization of muscle elasticity in ballistic exercises.     

Potentiation of the mechanical behavior of the human skeletal muscle through prestretching.

Force-velocity and power-velocity curves in a vertical jump involving movements around several joints were derived from vertical ground reaction forces and knee angular velocities. The jumps were performed with weights from 10 to 160 kg added on the shoulders. The obtained curves from a semi-squatting static starting position resembled those reported for isolated muscles or single muscle groups. Vertical jumps were also performed in the conditions where the shortening of the leg extensors was preceded by prestretching of the active muscles either through a preparatory counter-movement or dropping down on the force-platform from the various heights ranging from 20 to 100 cm. Prestretching modified through a range of velocities the force-velocity and power-velocity curves by increasing both the ground reaction forces and the calculated mechanical power. Thus the results are similar to those reported in isolated muscles. In studies with isolated muscle preparation the nervous connections have not been intact and therefore it is suggested that increase in the performance of the skeletal muscles through prestretching, in the conditions of the present study, was attributed to the combined effects of the utilization of stored elastic energy and the reflex potentiation of muscle activation.     

Influence of the abdominal vagi and gastric antrum on humoral control of gastric acid secretion

The influence of the abdominal vagi (especially the gastric antral branch), the antrum, and the duodenum on humoral control of gastric acid secretion was studied in 9 dogs with Heidenhain pouches (HP). The dogs were divided into 2 groups and subjected to the following sequential operations:Group I: (6 dogs) The first operation was section of the antral branch of the vagus nerve. The second operation was antrectomy with Billroth I gastroduodenostomy. The third operation was transthoracic truncal vagotomy.Group II: (3 dogs) The first operation was antrectomy and Billroth II gastrojejunostomy and the second operation was transthoracic truncal vagotomy. During the control period when the dogs had only an HP, pouch acid secretion and serum gastrin level increased after feeding. After antral vagotomy, both pouch secretion and the serum gastrin level after feeding were significantly lower. The second operation of antrectomy with Billroth I gastroduodenostomy in Group I resulted in a further significant decrease in both pouch acid secretion and serum gastrin level. Similar decreases occurred after the first operation of antrectomy with Billroth II gastrojejunostomy in Group II. In both groups, after the final operation of transthoracic truncal vagotomy, pouch acid secretion tended to increase, while the serum gastrin level increased slightly in Group I but not in Group II. It is concluded that vagal innervation of the antrum plays a role in gastrin release and gastric acid secretion.

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Résumé Nous avons étudié, chez 9 chiens porteurs d'une poche de Heidenhain (PH), l'influence des branches abdominales des nerfs vagues (plus spécialement le rameau antral), de l'antre et du duodénum sur le contrôle hormonal de la sécrétion gastrique acide. Deux groupes de chiens ont été soumis aux opérations suivantes:Dans le groupe I (6 chiens), la première opération est une section du rameau antral du vague, la deuxième une antrectomie avec gastroduodénostomie de type Billroth I, la troisième une vagotomie par voie thoracique.Dans le groupe II (3 chiens), la première opération est une antrectomie avec gastrojéjunostomie de type Billroth II et la seconde une vagotomie par voie thoracique.Pendant la période de contrôle, la sécrétion acide de la PH et le taux de gastrine sérique augmentent après un repas. Après vagotomie antrale, la sécrétion de la PH et les valeurs de gastrine sérique sont réduites de façon significative. Dans le groupe I, l'antrectomie avec gastroduodénostomie diminue encore la sécrétion d'acide de la PH et la gastrinémie. Dans le groupe II, F antrectomie avec gastrojéjunostomie donne des réductions de même importance. Dans les deux groupes, la sécrétion acide de la PH tend à s'élever après vagotomie par voie thoracique. La gastrinémie augmente légèrement dans le groupe I, mais pas dans le groupe II. En conclusion, l'innervation vagale de l'antre influence la libération de gastrine et la sécrétion gastrique acide.