Exercise mode affects the time to achieve VO2max without influencing maximal exercise time at the intensity associated with VO2max in triathletes

The objective of this study was to analyze, in triathletes, the possible influence of the exercise mode (running x cycling) on time to exhaustion (TTE) and oxygen uptake (VO2) response during exercise performed at the intensity associated with the achievement of maximal oxygen uptake (IVO2max). Eleven male triathletes (21.8 +/- 3.8 yr) performed the following tests on different days on a motorized treadmill and on a cycle ergometer: 1) incremental tests in order to determine VO2max and IVO2max and, 2) constant work rate tests to exhaustion at IVO2max to determine TTE and to describe VO2 response (time to achieve VO2max-TAVO(2max) and time maintained at VO2max-TMVO2max). No differences were found in VO2max, TTE and TMVO2max obtained on the treadmill tests (63.7 +/- 4.7 ml.kg(-1).min(-1); 324.6 +/- 109.1 s; 178.9 +/- 93.6 s) and cycle ergometer tests (61.4 +/- 4.5 ml.kg(-1).min(-1); 390.4 +/- 114.4 s; 213.5 +/- 102.4 s). However, TAVO(2max) was influenced by exercise mode (145.7 +/- 25.3 vs. 176.8 +/- 20.1 s; in treadmill and cycle ergometer, respectively; p = 0.006). It is concluded that exercise modality affects the TAVO(2max) without influencing TTE and TMVO2max during exercise at IVO2max in triathletes.

Serum and plasma hormonal concentrations are sensitive to periods of intensity and volume of soccer training

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of recovery manipulation after hyperlactemia induction on the lactate minimum intensity

This study analyzed the influence of recovery phase manipulation after hyperlactemia induction on the lactate minimum intensity during treadmill running. Twelve male runners (24.6 +/- A 6.3 years; 172 +/- A 8.0 cm and 62.6 +/- A 6.1 kg) performed three lactate minimum tests involving passive (LMT(P)) and active recoveries at 30%vVO(2max) (LMT(A30)) and 50%vVO(2max) (LMT(A50)) in the 8-min period following initial sprints. During subsequent graded exercise, lactate minimum speed and VO(2) in LMT(A50) (12.8 +/- A 1.5 km h(-1) and 40.3 +/- A 5.1 ml kg(-1) min(-1)) were significantly lower (P < 0.05) than those in LMT(A30) (13.3 +/- A 1.6 km h(-1) and 42.9 +/- A 5.3 ml kg(-1) min(-1)) and LMT(P) (13.8 +/- A 1.6 km h(-1) and 43.6 +/- A 6.1 ml kg(-1) min(-1)). In addition, lactate minimum speed in LMT(A30) was significantly lower (P < 0.05) than that in LMT(P). These results suggest that lactate minimum intensity is lowered by active recovery after hyperlactemia induction in an intensity-dependent manner compared to passive recovery.

Does 75% of the difference between VO2 at lactate threshold and VO2max lie at the severe-intensity domain in well-trained cyclists?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of Exercise Mode on the Oxygen Uptake Kinetic Response to Severe-Intensity Exercise in Prepubertal Children

The objective of this study was to verify the effect of the exercise mode on slow component of VO(2) (VO(2)SC) in children aged 11-12 years during severe-intensity exercise. After determination of the lactate threshold (LT) and peak VO(2) (VO(2)peak) in both cycling (CE) and running exercise (TR), fourteen active boys completed a series of "square-wave" transitions of 6-min duration at 75%Delta [75%Delta = LT + 0.75 X (VO(2)peak-LT)l to determine the VO(2) kinetics. The VO(2)SC was significantly higher in CE (180.5 +/- 155.8 ml . min(-1)) than in TR (113.0 +/- 84.2 ml . min(-1)). We can conclude that, although a VO(2)SC does indeed develop during TR in children, its magnitude is considerably lower than in CE during severe-intensity exercise.

Low intensity laser therapy (LILT) in vivo acts on the neutrophils recruitment and chemokines/cytokines levels in a model of acute pulmonary inflammation induced by aerosol of lipopolysaccharide from Escherichia coli in rat

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Detection of T lymphocytes in intestine of broiler chicks treated with Lactobacillus spp. and challenged with Salmonella enterica serovar enteritidis

The expression of immune response in the form of leukocytic infiltrate by CD3+, CD4+, and CD8+ cells in the epithelium and in the intestinal lamina propria of chicks was studied in the present work by means of immunohistochemical reaction. The chicks were treated with Lactobacillus spp. or cecal microflora (CM) and experimentally challenged or not with Salmonella enterica serovar Enteritidis. The 320 birds utilized were divided into 4 groups containing 80 chicks each and submitted to treatments with Lactobacillus reuteri, Lactobacillus salivarius, Lactobacillus acidophilus, and CM. Each group was subdivided into 4 subgroups of 20 birds each and classified into a subgroup that did not receive treatment (negative control), subgroup treated, subgroup treated and challenged with Salmonella Enteritidis, and subgroup only challenged with Salmonella Enteritidis (positive control). The results obtained show that the treatment with L. reuteri, L. salivarius, L. acidophilus, or CM and challenged or not with Salmonella Enteritidis determine immune response in the form of leukocytic infiltrate by CD3+ and CD8+ lymphocytes followed by CD4+ in the epithelium and in the lamina propria of the duodenum, jejunum, and cecum of chicks up to 12 d of age. The quantity of CD3+ lymphocytes was significantly higher (P < 0.05) in the intestine of chicks treated with L. acidophilus or CM and challenged or not with Salmonella Enteritidis; however, the higher quantity of CD8+ lymphocytes was in the intestine of chicks treated with CM and challenged with Salmonella Enteritidis. The duodenum was the segment in which the immune response by T cells (CD3+, CD4+, and CD8+) was stimulated with the greatest intensity, followed by, respectively, the jejunum and cecum. The quantity of CD3+ lymphocytes present in the duodenum, jejunum, and cecum increases with the age of chicks, independent of the stimulus determined by treatments or challenge.

Reduced Insulin Secretion in Protein Malnourished Mice Is Associated with Multiple Changes in the beta-Cell Stimulus-Secretion Coupling

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Rat nephrotoxic nephritis. The relation between the type and intensity of induced histological lesions and the content of antiglomerular basement membrane antibodies of the inoculated serum

Six groups of 6 rats received equal doses (0.8 ml/100 g of body weight) of different rabbit anti rat kidney sera. The titer of anti GBM antibodies in the sera was evaluated by indirect immunofluorescent test in isolated GBM (IIT GBM). Rats of groups 1, 2, 3, 5, 6 received anti rat GBM sera with titers of 1/320, 1/240, 1/160, 1/60, 1/30 respectively. Group 4 received anti rat kidney serum with a titer of 1/80. The rats of group 1 died from 1 to 5 minutes after inoculation and their kidney were congested, with hialine trombi occluding arterioles and glomerular capillaries. The rats of group 2 and one of group 3 died from 2 to 15 days after inoculation and diffuse cortical necrosis was found. The remaining rats were sacrificed 2 months after inoculation. The kidneys were normal in control group; chronic membranoproliferative glomerulonephritis was observed in group 3 and 4, membranoproliferative glomerulonephritis in group 5 and minimal changes in group 6. By immunofluorescence rabbit gammaglobulin was seen in GBM of group 3, 4, 5 and 6. The IIT GBM performed in the eluates of the kidneys revealed the presence of heterologous antibody in groups 1, 2, 3, 4, 5 and 6 and autologous antibody in groups 3, 4 and 5. One concludes that the IIT GBM identifies and quantifies antibodies which have the property of damaging the kidney.

Short-period variation of cosmic-ray intensity and ozone density observed in the stratosphere

The energy deposition by slowing-down of energetic ionizing particles in the atmosphere enhances the production of constituent concentration which perturbs and eventually destroys the ozone (OZ) layer. Near the Brazilian anomaly region the cosmic-ray (CR) intensity varies greatly due to the magnetic activity in that region. In order to study these variations, stratospheric balloons were launched to measure, simultaneously, the CR and OZ fluxes in the atmosphere. The Fourier-analysed data collected during the flight on April 22, 1989 show evidences of a short-period variation for both fluxes measured. Attempts to verify the physical mechanisms which associate the CR change with the OZ one are not conclusive due to limited data observed on that event. © 1993 Società Italiana di Fisica.

Judd-Ofelt analysis of Pr3+ ions in fluoroindate glasses: Influence of odd third order intensity parameters

In this work an analysis of the Judd-Ofelt phenomenological Ωλ intensity parameters for the Pr3+ ion in fluoroindate glass is made. Different Pr3+ concentrations, namely 1, 2, 3 and 4 mol% are used. The experimental oscillator strengths have been determined from the absorption spectra. A consistent set of parameters is obtained only with the inclusion of odd rank third order intensity parameters and if the band at 21 470 cm-1 is assigned to the 3H4 → 3P1 transition and the 1I6 component is incorporated in the 3H4 → 3P2 transition at 22 700 cm-1.

Spectroscopic study of the interaction of Nd3+ with amino acids: Phenomenological 4f-4f intensity parameters

We have studied the bevahior of the phenomenological 4f-4f intensity parameters in compounds of the Nd ion with glycine, L-aspartic acid, L-glutamic acid, L-histidine, DL-malic acid and Aspartame™ in aqueous solution, as a function of the pK values and partial charges on the oxygens of the carboxylate groups of these molecules. The results are discussed and qualitatively interpreted in terms of the forced electric dipole and dynamic coupling mechanisms of the 4f-4f intensities, thus indicating that the forced electric dipole mechanism is dominant.

Effect of an acute β-adrenergic blockade on exercise intensity corresponding to the lactate minimum

β-Adrenoreceptor blockade is reported to impair endurance, power output and work capacity in healthy subjects and patients with hypertension. The purpose of this study was to investigate the effect in eighth athletic males of an acute β-adrenergic blockade with propranolol on their individual power output corresponding to a defined lactate minimum (LM). Eight fit males (cyclist or triathlete) performed a protocol to determine the power output corresponding to their individual LM (defined from an incremental exercise test after a rapidly induced exercise lactic acidosis). This protocol was performed twice in a double-blind randomized order by each athlete first ingesting propranolol (80mg) and in a second trial a placebo, 120 minutes respectively prior to the test sequence. The blood lactate concentration obtained 7 minutes after anaerobic exercise (a Wingate test) was significantly lower after acute β-adrenergic blockade (8.6 ± 1.6mM) than under the placebo condition (11.7 ± 1.6mM). The work rate at the LM was lowered from 215.0 ± 18.6 to 184.0 ± 18.6 watts and heart rate at the LM was reduced from 165 ± 1.5 to 132 ± 2.2 beats/minute as a result of the blockade. There was a non-significant correlation (r = 0.29) between the power output at the LM with and without acute β-adrenergic blockade. In conclusion, since the intensity corresponding to the LM is related to aerobic performance, the results of the present study, are able to explain in part, the reduction in aerobic power output produced during β-adrenergic blockade.