Physical exercise activates the poly(ADP-ribosyl)ation system in rat testes.

Given the high sensitivity of the male reproductive system to oxidative stress and to temperature changes, the amount of germ cell apoptosis and the activation of the poly(ADP-ribosyl)ation system (a very sensitive index of genotoxic stress) were evaluated in the testicular tissue of adult rats which underwent a 10-wk treadmill training, according to either a mild or a strong protocol; rats were sacrificed 24 h after the last training session or after a single bout of an additional stressing exercise (30 min of swimming). Controls were untrained rats (one resting group and one group with acute exercise). Both training and acute exercise increased marginally germ cell apoptotic indexes (caspase-induced poly(ADP-ribose) polymerase fragmentation and TUNEL-positive cells), while the activity of poly(ADP-ribose) polymerase and poly(ADP-ribose) glycohydrolase enzymes was affected in a way that suggests that acute exercise is associated with reversible genotoxic stress, and that training induces adaptive responses, as demonstrated by the activation of poly(ADP-ribose) polymerase system without subsequent increase in apoptosis.

Nutritional status and dietary patterns in disabled people.

BACKGROUND AND AIM: Obesity, cardiovascular diseases, diabetes and osteoporosis are the most frequent pathologies among people with a severe reduction of physical activity. The impairment in nutritional status, consequent to quantitative and qualitative inadequacy of diet, could be one of the first steps in the development of co-morbidities in disabled subjects. In order to evaluate this hypothesis we investigated the nutritional status and the food intake in patients with physical or mental disabilities. METHODS AND RESULTS: Thirty-seven disabled subjects (24 with exclusively physical inactivity and 13 with mental retardation and physical inactivity) mean age 33.5+/-9.2 years and 25 healthy subjects (mean age 31.0+/-9.3 years) were enrolled. Anthropometric measurements, indirect calorimetry, dual-energy X-ray absorptiometry, dietary intake and biochemical parameters were collected for each subject. Forty percent of disabled were overweight and 14% were obese. Fat free mass (FFM) and bone mineral content (BMC) was lower and fat mass (FM) was higher than able-bodied control. Absolute resting energy expenditure (REE) was lower in disabled subjects, but this difference disappeared when REE was normalized to FFM. Dietary intake resulted unbalanced (16%, 31%, 50% of total daily energy intake derived from protein, lipid and carbohydrate respectively) with a distribution of dietary fatty acid quite far from the recommended ratio [3.1(SFA):4.1(MUFA):1.0(PUFA)] and an excessive consumption of simple carbohydrates (mean intake 17.5+/-4.9%). Insufficient intake of fibre, iron, calcium, potassium and zinc was also found. Finally, alterations in the cholesterol profile were evident in more than one third of the disabled subjects, whereas fasting glucose intolerance was evident in one fourth. CONCLUSION: This study shows a consistent nutritional status impairment in disabled patients resulting in an reduction of FFM and BMC, in an over-representation of FM and in a number of biochemical risk factors for cardiovascular disease. The altered nutritional status is counterparted by a widespread inadequacy of dietary patterns. This nutritional and dietary impairment occurs both in subjects with mental and physical diseases.

Effects of short term cast wearing on respiratory and cardiac responses to submaximal and maximal exercise in adolescents with idiopathic scoliosis.

AIM: Bracing is widely used to treat adolescent scoliosis. However, bracing may also affect respiratory and cardiovascular function. In this thirteen-weeks longitudinal study we evaluated the effect of brace wearing on maximal and submaximal cardiorespiratory capacity in adolescents with moderate idiopathic scoliosis. METHODS: Eight boys and 8 girls (12-18 years) with scoliosis of the thoracic spine (Cobb angle range 32 degrees - 42 degrees in boys and 32 degrees - 60 degrees in girls) were enrolled. Respiratory basal function (forced vital capacity, FVC, and forced expired volume in 1 s, FEV(1)) and cardiorespiratory adjustments to submaximal and maximal cycle ergometer exercise (heart rate, HR, pulmonary ventilation, VE, and oxygen consumption, VO(2)) were measured a week before fitting a brace, after 1 and 12 weeks of brace wearing, and a week after brace removal. RESULTS: With respect to pretreatment values: a) after 1 week of brace wearing FVC and FEV(1) were significantly reduced in both genders; b) after 12 weeks of bracing the amount of oxygen consumed per heart beat was reduced during maximal and submaximal exercises in females only; c) ventilatory efficiency was unchanged in both genders in each condition; d) oxygen uptake during maximal exercise was decreased (by about 10-20%) in females only; e) after brace removal all variables tended to regress to pretreatment values. CONCLUSIONS: Although data are preliminary and need to be confirmed on larger samples of patients, the brace appears to limit maximal exercise performance especially in girls, where it affects the cardiopulmonary efficiency. Thus, moderate physical exercise during brace wearing is advised to counteract respiratory, cardiovascular and muscle inefficiency due to ribcage movement limitations.

Body composition assessment in spinal cord injury subjects.

Total and segmental body composition (fat mass, FM; fat-free mass, FFM; bone mineral density, BMD) were evaluated in 13 sedentary spinal cord injury (SCI) subjects and in 13 able-bodied healthy males (control, C) using dual X-ray absorptiometry (DXA) and skinfold methods. In the SCI group, total FM was significantly higher (31.1+/-8.2 vs. 20.8+/-6.9%) and total FFM was significantly lower (62.2+/-8.9 vs. 73.5+/-6.4%) than in C subjects. Total BMD did not differ between the SCI and C groups (1.20+/-0.11 vs. 1.30+/-0.11 g/cm(2)). In the SCI group, segmental FM was higher in the legs and trunk, whereas BMD was lower in legs only. The skinfold method significantly underestimated FM in the SCI group. Body composition is severely modified in paralyzed segments. The predictive equations developed for healthy populations appear to be inapplicable to SCI subjects.

Swim training improves myocardial resistance to ischemia in rats.

As the relationship between training and ischemic heart disease is not yet unraveled, we test the hypothesis that, in a model free from environmental, behavioural, and neuro-hormonal factors, endurance training improves myocardial resistance to ischemia. As carbohydrate metabolism is relevant for myocardial resistance to ischemia, we also test whether hyperglycemia blunts the protective effect of training. Eight-week old rats were randomly assigned to four groups (n = 6-8): sedentary or trained (3-week swim program, up to 2 h/day), and normal or high-carbohydrate diet (50 g/l sucrose in drinking water). Excised hearts were perfused isovolumically (flow = 15 ml/min) with Krebs-Henseleit (2 mM free Ca++, 11 mM glucose, pH 7.38 +/- 0.02, PO2 = 670 +/- 6 mmHg, PCO2 = 43 +/- 1 mmHg, mean +/- SE), exposed to 60 min low-flow (1.5 ml/min) ischemia, and then reperfused for 30 min (15 ml/min). In normally fed rats training increased the stroke volume index (97.5 +/- 13.0 vs. 72.6 +/- 6.2 microl, P = 0.05), depressed diastolic contracture (+2.3 +/- 2.0 vs. +24.2 +/- 6.7 mmHg, P = 0.02), improved the recovery of developed pressure x heart rate (33.8 +/- 2.3 vs. 24.1 +/- 3.3 mmHg/min/1000, P = 0.05), and decreased arrhythmias (P = 0.05). In high-carbohydrate-fed rats training induced myocardial hypertrophy (1.95 +/- 0.08 vs. 1.67 +/- 0.03 g, P = 0.02) and decreased arrhythmias but did not affect stroke volume, developed pressure x heart rate, and diastolic contracture. Thus endurance training improves myocardial resistance to ischemia but a high-carbohydrate diet partially blunts this protection. The occurrence of an inducible alteration able to modulate myocardial tolerance to ischemia may give clues to extend our knowledge of ischemic preconditioning.

Biological effects of prolonged exposure to ELF electromagnetic fields in rats: III. 50 Hz electromagnetic fields.

Groups of adult male Sprague Dawley rats (64 rats each) were exposed for 8 months to electromagnetic fields (EMF) of two different field strength combinations: 5microT - 1kV/m and 100microT - 5kV/m. A third group was sham exposed. Field exposure was 8 hrs/day for 5 days/week. Blood samples were collected for hematology determinations before the onset of exposure and at 12 week intervals. At sacrifice, liver, heart, mesenteric lymph nodes, bone marrow, and testes were collected for morphology and histology assessments, while the pineal gland and brain were collected for biochemical determinations. At both field strength combinations, no pathological changes were observed in animal growth rate, in morphology and histology of the collected tissue specimens (liver, heart, mesenteric lymph nodes, testes, bone marrow), and in serum chemistry. An increase in norepinephrine levels occurred in the pineal gland of rats exposed to the higher field strength. The major changes in the brain involved the opioid system in frontal cortex, parietal cortex, and hippocampus. From the present findings it may be hypothesized that EMF may cause alteration of some brain functions.

Effects of trimetazidine on metabolic and functional recovery of postischemic rat hearts.

The objective of this study was to test the hypothesis that the beneficial effect of trimetazidine during reflow of ischemic hearts is mediated by energy sparing and ATP pool preservation during ischemia. Isolated rat hearts (controls and rats treated with 10(-6) M trimetazidine, n = 17 per group) underwent the following protocol: baseline perfusion at normal coronary flow (20 minutes), low-flow ischemia at 10% flow (60 minutes), and reflow (20 minutes). We measured contractile function, O2 uptake, lactate release, venous pH and PCO2, and the tissue content of high-energy phosphates and their metabolites. During baseline, trimetazidine induced higher venous pH and lower PCO2 without influencing performance and metabolism. During low-flow ischemia, trimetazidine reduced myocardial performance (P = 0.04) and ATP turnover (P = 0.02). During reflow, trimetazidine improved performance (91 +/- 6% versus. 55 +/- 6% of baseline), prevented the development of diastolic contracture and coronary resistance, and reduced myocardial depletion of adenine nucleotides and purines. ATP turnover during low-flow ischemia was inversely related to recovery of the rate-pressure product (P = 0.002), end-diastolic pressure (P = 0.007), and perfusion pressure (P = 0.05). We conclude that trimetazidine-induced protection of ischemic-reperfused hearts is also mediated by energy sparing during ischemia, which presumably preserves the ATP pool during reflow.

Biologic effects of prolonged exposure to ELF electromagnetic fields in rats: II. 50 Hz magnetic fields.

To provide possible laboratory support to health risk evaluation associated with long-term, low-intensity magnetic field exposure, 256 male albino rats and an equal number of control animals (initial age 12 weeks) were exposed 22 h/day to a 50 Hz magnetic flux density of 5 microT for 32 weeks (a total of about 5000 h). Hematology was studied from blood samples before exposure to the field and at 12 week intervals. Morphology and histology of liver, heart, mesenteric lymph nodes, and testes as well as brain neurotransmitters were assessed at the end of the exposure period. In two identical sets of experiments, no significant differences in the investigated variables were found between exposed and sham-exposed animals. It is concluded that continuous exposure to a 50 Hz magnetic field of 5 microT from week 12 to week 44, which makes up approximately 70% of the life span of the rat before sacrifice, does not cause changes in growth rate, in the morphology and histology of liver, heart, mesenteric lymph nodes, testes, and bone marrow, in hematology and hematochemistry, or in the neurotransmitters dopamine and serotonin.

Maximal isometric force and muscle cross-sectional area of the forearm in fencers.

The maximal isometric force (MIF) of a muscle is directly related to its cross-sectional area (CSA). Strength training produces an increase in muscular force while muscular hypertrophy becomes appreciable at a later time; in asymmetric sports, training causes significant increases in force and muscular mass of the dominant limb of the athlete. The aim of this study was to analyse the differences in muscular force and trophism between the dominant and non-dominant forearms in fencers and in controls. The data of 17 male distance runners (age 21.4 +/- 2.4 years, body mass 74.0 +/- 5.0 kg, height 180 +/- 6 cm) were compared with those of 58 male fencers (age 23.0 +/- 6.7 years, body mass 71.9 +/- 9.3 kg, height 178 +/- 7 cm) drawn from the ranking lists of the National Fencing Committee. They trained for a mean of 11.4 +/- 6.0 (range 2-36) years, commencing at 10.7 +/- 4.5 years of age. Cross-sectional area (muscle plus bone) was estimated in the dominant and non-dominant forearm using a simplified anthropometric method. Maximal isometric force was determined using a mechanical handgrip dynamometer. The differences in CSA and isometric force between the two limbs and between fencers and controls were tested using paired and unpaired Student's t-tests, respectively. Significant differences in CSA and maximal force were observed between the dominant and non-dominant forearm in fencers (both P < 0.001) and in controls (P < 0.005 and P < 0.001, respectively). The fencers showed a greater CSA (P < 0.001) and force (P < 0.001) in the dominant forearm compared with the control group. Furthermore, the differences between the dominant and non-dominant limb of the fencers were significantly greater than the differences between the dominant and non-dominant limb of the controls (P < 0.001 for CSA and P < 0.05 for force). No significant differences in stress ratio (force/CSA) were obtained in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Biologic effects of prolonged exposure to ELF electromagnetic fields in rats. I. 50 Hz electric fields.

A three-year investigation was conducted on the biological effects of high-intensity electric field exposures of rats for up to 18% of their life span. Two hundred and forty adult male rats, divided into groups of 20 animals each, were exposed at ground potential for 8 h/day at 25-kV/m and 100-kV/m 50-Hz electric fields or were sham exposed for 280, 440, and 1240 h. The corresponding ages at sacrifice were 140, 164, and 315 days. An additional group of 40 rats was investigated under similar experimental conditions after 440 h of exposure at floating potential. Independent of exposure duration, mode of grounding, and field strength, no statistical differences in body weight, morphology, and histology of the liver, heart, mesenteric lymph nodes, and blood variables (hematology and serum chemistry) were found in comparison with sham-exposed animals. Plasma levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone (TS) at sacrifice varied widely among experimental animals in the same group but did not differ in exposed compared with sham-exposed rats. A nonsignificant tendency toward a decrease in the testes/body weight ratio was found after 1240 h of exposure. Microscopic examination of a large number of specimens showed no quantitative or qualitative statistical differences in testes alterations either among exposed animals or between exposed and their corresponding sham-exposed groups. We conclude that 50-Hz electric field exposure, even of long duration at very high field strengths, does not induce harmful effects on tissues with high cellular turnover rates and does not impair the reproductive function of rats. Moreover, after exposure, all variables investigated were well within the normal physiological range.

Neurotransmitter amino acid variations in striatum of rats exposed to 50 Hz electric fields.

Concentration of neurotransmitter amino acids (Tau, Gly, Asp, Glu, Gln, Ala, GABA) were measured in rat striatum following varying exposure (320 to 1408 h) to high intensity (50 Hz) electric fields. Tissue extracts in methanol, after drying, were derivatized with dansyl chloride and the amino acids quantitated by high-pressure liquid chromatography with ultraviolet detection. Short exposures (320 h) to 100 kV/m field induced a decrease in almost all tested amino acids. Longer exposure times (640 h) to 25 and 100 kV/m were only associated with a decrease in Tau. A further increase of the exposure time (1240 and 1408 h) both at 25 and 180 kV/m were mainly associated with a reduction of the amino acid levels. It is concluded that electric fields in the range 20-180 kV/m generate bimodal variations in neurotransmitter amino acids with troughs at very short and longer exposure times, independent from the field strength.

Energy cost of walking with hip joint impairment.

The energy cost of walking was measured in 12 patients (age 39-73 years) with hip joint impairment and 10 healthy controls during unassisted walking (2-6 km.h-1) on a level treadmill surface and on a 5% incline. The energy cost of locomotion in most patients increased up to 50% and 70% during level-surface and uphill walking, respectively. This difference between patients and controls was probably due to the increased external mechanical work. The energy cost of walking, although related to pain experienced during walking but not to hip joint range of motion or to joint status evaluated radiographically, provides an additional variable when defining the conditions of disability and functional impairment in individuals with this pathological condition. [Gussoni M, Margonato V, Ventura R, et al: Energy cost of walking with hip joint impairment.

Energy cost of and energy sources for alpine skiing in top athletes.

O2 uptake (VO2) during exercise and at 2 min of the recovery along with blood lactate concentration 5 min after exercise were measured in an all-out special slalom (SS) and giant slalom (GS) performed by eight top male athletes and five controls in a field study. Heart rate (HR) was continuously monitored before, during, and after each task. On the basis of an energy equivalent of 3.15 ml O2 X kg body wt-1 for 1 mmol X 1-1 lactate accumulation and the assumption that the amount of O2 consumed in recovery is used to reconstitute approximately phosphates used during the exercise, the total energy cost (delta VO2 tot) could be calculated and subdivided into aerobic, lactic, and alactic fractions. In top athletes, delta VO2 tot was equal during SS and GS [7.28 +/- 1.14 (SD) and 7.47 +/- 0.89 liters for about 55- and 70-s performances, respectively]. When referred to time, the O2 expenditure rate was 2 and 1.6 times VO2max in SS and GS, respectively. In SS and GS, the energy sources were about 40% aerobic, 20% alactic , and 40% lactic metabolism. In control skiers, delta VO2 tot of GS was 6.12 +/- 1.45 liters for 77 s, amounting to about 1.3 VO2max, with the contribution of the different energy sources being roughly the same as in top skiers. HR reached maximal values in 30-40 s in all subjects for all conditions.

[Effect of high intensity (50Hz) electric stimulation on various cardiovascular parameters in the rabbit]. / Effetto del campo elettrico (a 50 Hz) di elevata intensita' su alcuni parametri cardiocircolatori nel coniglio.

The effect of AC (50 Hz) electric field (EL) of 80 kV/m on ECG, cardiac output (Q) and arterial pressure (AP) has been studied on 15 rabbits after 60 days of exposure for 8 hr a day and in an equal number of controls (C). Average heart rate value was 272 +/- 27.1 (+/- SD) b/min in C and 266 +/- 23.7 b/min in exposed animals. No alterations of ECG waves was found. Q (thermodilution method) was 234 +/- 22.4 ml/min X kg b.w. in C and 245 +/- 13.9 ml/min X kg in exp. respectively. Mean AP (direct measurement) was 102 +/- 3.5 mmHg and 104 +/- 5.1 mmHg in C and exp. respectively. The difference in the variables studied between the two groups is not statistically significant. In conclusion, chronic exposure at high intensity EL does not seem to affect the cardiovascular variables investigated.

Cardiac output and cardiac load during isometric exercise in man.

Cardiac output, heart rate, arterial pressure and indirect left ventricular oxygen consumption have been measured in three subjects during isometric contractions (50-170 kg) of the plantar flexors until fatigue was reached and during walking on a treadmill. Cardiac output was linearly related to VO2 for both exercises. However, for the same VO2, Q was four times higher during isometric effort than during walking. In the last 15 s of static tasks, HR was linearly increasing to VO2 and AP reached values of 160 and 125 Torr (systolic and diastolic respectively) independently of VO2. For comparable VO2 in static and isotonic exercises myocardial O2 uptake was doubled during isometric rather than during the isotonic exercise.

[Variation in weight and food intake of rats exposed to a high-intensity electrical field at 50 Hz]. / Variazioni ponderali ed assunzione di alimenti nel ratto esposto a campi elettrici di intensità elevata a 50 Hz.

The effects of exposure to electric fields at 50 Hz of various intensities (100, 25, 10 kV/m) on the food intake and body growth were determined in the rat at various stages of development. The different field intensities were induced between 1.5 by 2 m steel plates. At 100 kV/m, 25 rats were exposed 8 h/d for 48 days. In respect to controls, after 2 weeks of exposure a marked decrease of the growth rate was observed in exposed animals, but not of the food intake. At 25 kV/m 11 animals, 28 days old, were exposed 8 h/d for 35 days. A slight decrease in growth rate, statistically significant only at the 23rd and the 26th day of exposure, was found. No effect was observed on food intake and full recovery of body weight of exposed animals was achieved in 4 weeks after the end of the exposure. At 10 kV/m, in addition to 5 rats 28 days old, exposed 8 h/d for 35 days and to the corresponding controls, 15 "sham exposed" animals were studied. No significant difference in growth rate was found between the exposed animals and the two other groups. Food intake of exposed was for two weeks of treatment the same of control animals. Thereafter, there was tendency toward a higher food intake in the exposed animals being significant during recovery.

[Gonadal function in the rat exposed to a high intensity electric field of 50 Hz]. / La funzionalità gonadica nel ratto esposto a compi elettrici di intensità elevata a 50 Hz.

The effects of 50 Hz AC electric field of high intensity (100 kV/m) have been studied on the reproductive system of male rats exposed acutely (30 minutes a day) or chronically (8 hours a day) for up to 48 days. Groups of controls were studied simultaneously. Weight of the testicles, sperm viability, number of copulations, pregnancies, foetal implantations and reabsorptions as well as macro and microscopic anatomy have been investigated after mate with unexposed females. For acutely exposed animals, the number of copulations and fertility appeared lower than during chronic exposure. On the contrary, no changes were observed in sperm viability, morphology and in the others parameters under study. During chronic exposure no changes of any of the parameters analyzed occurred. However, in both modes of exposure the weight of the offsprings was about 10% lower than in controls. We conclude that exposure of male animals to extremely high electric field does not cause any damage to the reproductive system.