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Biomedical subjects

F Schena

Publications and source records attributed to F Schena.

46 records · Page 3Linked to original sources
PubMed1990

Serum ferritin and serum iron changes after cross-country and roller ski endurance races.

We have studied the variations induced in iron status parameters by four endurance races of different lengths. A comprehensive group of 48 healthy, non-iron deficient, endurance athletes were evaluated before and after four different cross-country and roller ski races: I = Skirollonga, roller ski race for individuals (n = 10), mean duration (MD) = 1 h 48 min; II = Marcialonga, cross-country ski race for individuals (n = 9) MD = 3 h 10 min; III = 12-h of Caldonazzo (Trento-Italy) roller ski relay race (n = 13) MD = 12 h; IV = 24-h of Pinzolo (Trento-Italy) cross-country ski relay race (n = 16) MD = 24 h. In the relays the MD includes both exercise and recovery times. Blood samples were taken before and after every race for the determination of the following haematological parameters: red blood count, haemoglobin, and packed cell volume, serum iron concentration [SI], serum ferritin concentration [FERR] and total iron binding capacity (TIBC). The results showed a constant significant increase of [FERR] after the races (+44.9% in I, +50.5% in II, +51.2% in III and +36.5% in IV, P less than 0.01) while [SI] increased only in the first two races (+28.2% in I and +19.7% in II, P less than 0.01) and showed a remarkable decrease in the longer races (-46.1% in III and -39% in IV, P less than 0.01). The TIBC increased in all the races (except II) to the same extent (range 10%-12%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Effects of acute hypoxia on ventilatory response at the onset of submaximal exercise.

In order to investigate the effects of acute hypoxia and accompanying hypocapnia on the ventilatory response at the onset of dynamic exercise, four healthy adult men performed 50W rectangular loads on a cycle-ergometer in normoxic (FIO2 = 0.21) and hypoxic (FIO2 = 0.11) conditions. No statistically significant differences in the initial ventilatory responses to exercise (both delta VI and delta VE assessed on a breath-by-breath basis) were found between eucapnic normoxia (PETO2 approximately 95, PETCO2 approximately 42 Torr) and hypocapnic hypoxia (PETO2 approximately 45, PETCO2 approximately 35 Torr). The present findings support the contention that the neurogenic ventilatory drive at the onset of early exercise is independent from PO2 and PCO2.

Adult↗
PubMed1990

Effects of training and iron supplementation on iron status of cross-country skiers.

We have studied the effects of iron treatment on iron deficient cross-country skiers. Kind and duration of their daily training were also considered. Forty-eight athletes were divided in three balanced groups: Group A received 160 mg ferritinic iron/die, Group B received the same amount of iron and 1 gr of ascorbic acid and Group C was untreated. Blood samples were taken at the start, after two months and four months of supplementation. Hematological and iron status parameters were determined. Average training duration was 80 min a day. Running was the most frequent method of training but also roll and country skiing were commonly used. At the initial sample low serum ferritin values were found in all the three groups (Group A = 23.3 micrograms/l, Group B = 20.9 micrograms/l and Group C = 23.5 micrograms/l). After iron treatment serum ferritin increased in Groups A and B (+67.8% and +63.6% respectively) but was slightly reduced in Group C. Serum iron was unchanged and total iron binding capacity decreased following ferritin increase. Ascorbic acid failed to increase iron absorption in Group B. A significant reduction of haptoglobin (-14% and -9% in Group A and B respectively) was also documented. We conclude that cross-country skiers extensively use running in their training and it may be one of the cause of their poor iron status. Ferritinic iron treatment seems to be effective in replacing iron stores in cross-country skiers who underwent heavy training.

Erythrocyte Count↗
PubMed1990

The effect of distension of the urinary bladder on left ventricular inotropic state in anesthetized dogs.

To decide whether distension of the urinary bladder reflexly affects the left ventricular inotropic state, experiments were performed in eight dogs anesthetized with pentobarbitone. After cannulation of both ureters the urinary bladder was repeatedly distended through a urethral catheter with warm Ringer solution at a steady intravesical pressure. The maximal rate of rise of left ventricular pressure (dP/dtmax) obtained at constant heart rate and cardiovascular pressures was used to assess changes in left ventricular inotropic state. Arterial blood pressure was prevented from changing by a pressurized reservoir containing warm Ringer solution and connected to the femoral arteries. Following prevention of the reflex increase in heart rate by atrial pacing, distension of the urinary bladder always increased the maximal rate of rise of left ventricular pressure in the eight dogs. There were no significant changes in left ventricular systolic or end-diastolic pressures. The increase in maximal rate of rise of left ventricular pressure was abolished following the administration of propranolol. The results indicate that a reflex increase in left ventricular inotropic state occurred in response to distension of the urinary bladder. This reflex response involved beta-adrenergic stimulation.

Animals↗
PubMed1989

Exercise tolerance and effects of training in young patients with cystic fibrosis and mild airway obstruction.

We evaluated the effects of an 8-week aerobic training (1 hr, three times a week) on physical performance of ten patients with cystic fibrosis (CF) (median age, 12.5 yr; range 11.1-15.3 yr), with mild airway obstruction (FEV1 = 77 +/- 22% pred.), and ten healthy age-matched children (CONTR) (median age, 12.7 yr; range 12.2-15.2 yr). Physical performance was tested with maximal incremental (MAX) and submaximal (SMAX) (fixed workload of 1.7 W/kg during 6 min) exercise tests on a cycle ergometer. These and standard spirometric and anthropometric measurements were performed at the beginning and end of a period with usual daily activity and one with the training program. The kinetics of ventilatory parameters at the onset and end of SMAX were displayed by fitting data on oxygen uptake and minute ventilation by monoexponential curves (least-squares method). At the start and the end of the training period, all children were timed for endurance run to voluntary exhaustion and for sprinting through an obstacle course. A pattern of relative hyperventilation during SMAX and of poor performance in endurance and obstacle runs were evident at the start of the training period in patients with CF. The effects of training on MAX and SMAX were small and partial; the improvement in field test performances was significant only for CF and could be attributed to improvement of skill and motivation.

Adolescent↗
PubMed1984

Cervical efferent vagal stimulation related or unrelated to cardiac cycles: comparison of negative atrial inotropic effects.

Efferent cervical vagal stimulations were performed in 4 anesthetized dogs, either with trains of stimuli of constant frequency (CONT), or with brief trains, triggered by the atrial electrical activity (TRIG). Heart rate was increased by cardiac pacing during vagal stimulations. Negative inotropic effects of vagal stimulations, evaluated as changes in atrial contractility, were partially inhibited by cardiac acceleration during CONT, but were unaffected during TRIG. It is concluded that the number of stimuli per cycle, not the number of stimuli per second, is the critical factor for parasympathetic heart regulation.

Animals↗
PubMedDate not supplied

Total and free PSA serum concentrations are not influenced by extensive physical exercise and bicycle riding.

Vigorous and prolonged physical exercise and mechanical involvement of the perineal region might influence prostatic function and measurement of both total (PSA) and free prostate specific antigen (fPSA), decreasing the diagnostic efficiency of the laboratory screening for either benign or neoplastic prostate disorders in athletes. To investigate the effects of regular and strenuous physical exercise with or without bicycle riding on integrity and biochemical function of prostatic tissue, we measured serum PSA and fPSA in 69 elite and professional cyclists, 31 members of the Italian national cross-country ski team, and in 43 sedentary healthy controls. The concentration of both PSA and fPSA did not differ significantly between sedentary individuals and physically active cross-country skiers (PSA 0.43 +/- 0.30 vs. 0.36+/-0.25, ns; fPSA 0.16+/-0.12 vs. 0.12+/-0.12, ns) or cyclists (PSA 0.43 +/- 0.30 vs. 0.36 +/- 0.23, ns; fPSA 0.16 +/- 0.12 vs. 0.13 +/- 0.08, ns), and the relative distribution of values appeared almost overlapping. We hypothesize that neither a heavy and regular physical exercise nor the extensive and prolonged mechanical involvement of the prostate region by the bicycle riding have significant influence on release of both PSA and fPSA.

Adult↗
PubMedDate not supplied

Ramipril inhibits in vitro human mesangial cell proliferation and platelet-derived growth factor expression.

Angiotensin-converting enzyme (ACE) inhibitors are antihypertensive drugs that have been shown to reduce proteinuria and to slow down the progression of renal function deterioration in different models of chronic glomerular disease. Major pathogenetic features of progressive glomerular injury leading to glomerulosclerosis are mesangial cell proliferation and platelet-derived growth factor (PDGF) expression. The aim of the present study was to evaluate the effect of ramipril, an ACE inhibitor, on these two potential therapeutic targets. Thus, the effect of ramipril on DNA synthesis, cell proliferation and PDGF A and B chain gene expression in fetal calf serum (FCS)-activated cultured human glomerular mesangial cells was investigated. DNA synthesis was evaluated by tritiated thymidine incorporation, cell proliferation by direct cell counting and cell viability by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT). PDGF A and B chain gene expressions were studied by Northern blot and RT-PCR, respectively. In a dose-dependent manner ramipril inhibited the FCS-induced DNA synthesis and cell proliferation. This effect was not dependent upon a toxic effect as demonstrated by MTT. The antiproliferative effect of ramipril was most likely independent of its ability to inhibit ACE present in the FCS and/or expressed by the cells, since a synthetic peptide that specifically inhibits ACE, at the same molar concentrations, did not inhibit FCS-stimulated DNA synthesis. Moreover, ramipril significantly reduced FCS-induced PDGF A and B chain gene expression. Finally, ramipril completely abolished the PDGF A and B chain gene expression induced by phorbol 12-myristate 13-acetate, a specific protein kinase C activator, suggesting a site of action downstream of this enzyme in the mitogenic signal transduction pathway. Our study would suggest that the modulatory action of ramipril on activated mesangial cell proliferation and PDGF expression is independent of its ability to inhibit ACE and could represent an additional mechanism in the renal protective effects of this drug.

Angiotensin-Converting Enzyme Inhibitors↗
PubMedDate not supplied

The heart as a biological clock: phase-locking between heart and efferent vagal activity.

Experiments were performed to evaluate whether the negative inotropic effect of efferent vagal stimulation is more strictly related to the number of stimuli falling with each cardiac cycle (St/c) or to the number of stimuli per second (St/s). Therefore, vagal stimulations were performed in anaesthetized dogs either with constant frequency (CONT), or with trains of 3 stimuli triggered by each atrial activation (SYNCHR). An atrial contractility index was measured while increasing heart rate by artificial heart pacing during CONT and SYNCHR vagal stimulations. The negative inotropic parasympathetic effect was reduced in the former protocol (St/s constant, St/c reduced) and did not change in the latter. It was concluded that the effect of vagal stimulation is more strictly related to St/c rather than to St/s. We suggest that the heart cycle operates as a biological clock with respect to cardiac vagal control.

Animals↗