Screening young athletes for prevention of sudden cardiac death: Practical recommendations for sports physicians.

Regular intensive exercise in athletes increases the relative risk of sudden cardiac death (SCD) compared with the relatively sedentary population. Most cases of SCD are due to silent cardiovascular diseases, and pre-participation screening of athletes at risk of SCD is thus of major importance. However, medical guidelines and recommendations differ widely between countries. In Italy, the National Health System recommends pre-participation screening for all competitive athletes including personal and family history, a physical examination, and a resting 12-lead electrocardiogram (ECG). In the United States, the American College of Cardiology and the American Heart Association recommend a pre-participation screening program limited to the use of specific questionnaires and a clinical examination. The value of a 12-lead ECG is debated based on issues surrounding cost-efficiency and feasibility. The aim of this review was to focus on (i) the incidence rate of cardiac diseases in relation to SCD; (ii) the value of conducting a questionnaire and a physical examination; (iii) the value of a 12-lead resting ECG; (iv) the importance of other cardiac evaluations in the prevention of SCD; and (v) the best practice for pre-participation screening.

Scientific approach to the 1-h cycling world record: a case study.

The purpose of this study was to describe the physiological and aerodynamic characteristics and the preparation for a successful attempt to break the 1-h cycling world record. An elite professional road cyclist (30 yr, 188 cm, 81 kg) performed an incremental laboratory test to assess maximal power output (W(max)) and power output (W(OBLA)), estimated speed (V(OBLA)), and heart rate (HR(OBLA)) at the onset of blood lactate accumulation (OBLA). He also completed an incremental velodrome (cycling track) test (VT1), during which V(OBLAVT1) and HR(OBLAVT1) were measured and W(OBLAVT1) was estimated. W(max) was 572 W, W(OBLA) 505 W, V(OBLA) 52.88 km/h, and HR(OBLA) 183 beats/min. V(OBLAVT1), HR(OBLAVT1), and W(OBLAVT1) were 52.7 km/h, 180 beats/min, and 500.6 W, respectively. Drag coefficient and shape coefficient, measured in a wind tunnel, were 0. 244 and 0.65 m(2), respectively. The cyclist set a world record of 53,040 m, with an estimated average power output of 509.5 W. Based on direct laboratory data of the power vs. oxygen uptake relationship for this cyclist, this is slightly higher than the 497. 25 W corresponding to his oxygen uptake at OBLA (5.65 l/min). In conclusion, 1) the 1-h cycling world record is the result of the interaction between physiological and aerodynamic characteristics; and 2) performance in this event can be predicted using mathematical models that integrate the principal performance-determining variables.

Level ground and uphill cycling ability in professional road cycling.

PURPOSE: To evaluate the physiological capacities and performance of professional road cyclists in relation to their morphotype-dependent speciality. METHODS: 24 world-class cyclists, classified as flat terrain (FT, N = 5), time trial (TT, N = 4), all terrain (AT, N = 6). and uphill (UH, N = 9) specialists, completed an incremental laboratory cycling test to assess maximal power output (Wmax), maximal oxygen uptake (VO2max), lactate threshold (LT), and onset of blood lactate accumulation (OBLA). RESULTS: UH had a higher frontal area (FA):body mass (BM) ratio (5.23 +/- 0.09 m2 x kg(-1) x 10(-3)) than FT and TT (P < 0.05). FT showed the highest absolute Wmax (481 +/- 18 W), and UH the highest Wmax relative to BM (6.47 +/- 0.33 W x kg(-1)). WLT and W(OBLA) values were significantly higher in FT (356 +/- 41 and 417 +/- 45 W) and TT (357 +/- 41 and 409 +/- 46 W) than in UH (308 +/- 46 and 356 +/- 41). Scaling of these values relative to FA and BM exponents 0.32 and 0.79 minimized group differences, but considerable differences among mean group values remained. FT and TT had the highest Wmax per FA unit (1300 +/- 62 and 1293 +/- 57 W x m2), whereas TT had the highest absolute W x kg(-0.32) and W x kg(-0.79), as well as W x kg(-0.32), W x kg(-0.79), and W x m2 at the LT and OBLA. CONCLUSIONS: i) Scaling of maximal and submaximal physiological values showed a performance advantage of TT over FT, AT, and UH in all cycling terrains and conditions; and ii) mass exponents of 0.32 and 1 were the most appropriate to evaluate level and uphill cycling ability, respectively, whereas absolute Wmax values are recommended for performance-prediction in short events on level terrain, and W(LT) and W(OBLA) in longer time trials and uphill cycling.

[Inappropriate antidiuretic hormone secretion syndrome: a rare manifestation of prostatic adenocarcinoma]. / Síndrome de secreción inadecuada de hormona antidiurética: una rara manifestación de adenocarcinoma prostático.

OBJECTIVE: Prostatic cancer can produce signs and symptoms by local growth, direct invasion or distant metastases. In rare occasions, these tumors can show a clinical variance due to trophic factors, biologically active, secreted in neoplastic environment but with systemic relevance. These syndromes are called paraneoplastic syndromes. This uncommon condition is described herein. METHOD/RESULTS: We report a case of inappropriate antidiuretic hormone secretion as the presenting feature of advanced prostatic carcinoma. The pathogenic features, diagnostic and therapeutic aspects are reviewed. CONCLUSIONS: Although its frequency is low, we must consider prostatic carcinoma in patients with inappropriate antidiuretic hormone secretion syndrome. When the acute situation is resolved, hormonal treatment in disseminated carcinomas will return to normal the clinical and analytical parameters derived from this syndrome.

[Metachronous metastasis in ureteral stump secondary to ipsilateral renal adenocarcinoma]. / Metástasis metacrónica en muñón ureteral secundaria a adenocarcinoma renal ipsilateral.

OBJECTIVES: Ureteral metastasis from renal adenocarcinoma is uncommon. The rarity of this disease prompted us to report on the present case, with special reference to diagnosis. METHODS/RESULTS: A patient with metachronous metastasis in the ureteral stump from clear cell renal adenocarcinoma resected three years earlier is described. The etiopathogenic, clinical, diagnostic and therapeutic aspects are briefly reviewed. CONCLUSIONS: Ureteral metastases, although uncommon, are generally ipsilateral to the renal tumor and arise from aggressive renal carcinomas that are locally advanced with vascular and/or lymphatic spread. We underscore the importance of retrograde pyelography and ureterorenoscopy in the diagnostic workup of all patients with gross hematuria following nephrectomy due to hypernephroma.

[Ureteral endometriosis]. / Endometriosis del uréter.

OBJECTIVES: Ureteral involvement due to endometriosis is uncommon. Its silent onset and the progression of ureteral obstruction, if undiagnosed, can lead to the loss of the renal unit. The present case is described to underscore the importance of early diagnosis. METHODS/RESULTS: We report on a patient with obstructive uropathy secondary to intrinsic ureteric endometriosis that had undergone nephrectomy due to parenchymal destruction. One year following resection of the endovesical portion, recurrence in the ureteral stump was observed. The clinical features, the diagnostic and clinical aspects are briefly discussed. CONCLUSIONS: Although ureteric involvement is uncommon, renal function of patients with pelvic endometriosis must be followed closely by analyses, ultrasound and/or intravenous urography for early detection of this condition.

[Benign retroperitoneal schwannoma]. / Schwannoma retroperitoneal benigno.

Herein we describe a case of benign retroperitoneal schwannoma, an uncommon lesion that had been incidentally discovered. The different terms used to refer to this disease entity, its histological features, diagnosis and treatment are discussed.

Effect of thyroid hormones on 5'-nucleotidase of isolated rat fat cells.

5'-Nucleotidase was measured in isolated fat cells from normal, hypothyroid and hyperthyroid rats. This was done to find out whether thyroid hormones had an effect on the production of adenosine by the fat cell. The results showed that 5'-nucleotidase is modified when the rats received injections of 3,3',5-triiodo-L-thyronine (T3). There was no change in the enzyme in hypothyroidism or when T3 was added to incubation of cells.

Lipolysis by corticotropin in fat cells from hypothyroid rats. Effect of adenosine deaminase.

Thyroid hormones are required for maximal stimulation of lipolysis of fat cells by catecholamines corticotropin and glucagon. Several reasons have been given to explain this fact, but all of them are controversial and still not definitive. It has been proposed that adenosine is an important factor in the low lipolytic response to catecholamines by fat cells of hypothyroid rats. This proposal has been studied with corticotropin. There has been no recuperation of maximal lipolysis when fat cells of hypothyroid rats were stimulated by corticotropin in the presence of adenosine deaminase.

Action of a water soluble splenic material on anaesthetized rat blood pressure.

The effects of a biologically active water-soluble splenic material on the rat blood pressure are described. The endovenous perfusion of the splenic material in acidified and alkalinized forms caused significant increases of the mean blood pressure in normal, vagotomized and pithed rats, showing that, in contradiction to previous reports, changes in pH did not affect its hypertensive activity. In normal rats, the hypertensive responses were not affected by the alpha- and beta-adrenoceptor antagonists: tolazoline, ergotoxine and propranolol, supporting the previously stated view that adrenergic mechanisms are not involved. In addition, the aforementioned results obtained in vagotomized and pithed rats suggest a lack of involvement of cardiac and vascular nervous mechanisms.

[Effect of various adenine derivatives on gastric acid secretion in the isolated rat stomach]. / Efecto de algunos derivados de la adenina sobre la secreción gástrica de ácido en estómago aislado de rata.

The adenine derivatives adenosine 5'-triphosphate (ATP), adenosine 5'-diphosphate (ADP), adenosine 5'-monophosphate (AMP) and adenosine (AD), in concentrations of 10(-3)M and 10(-4)M caused significant and dose-related modifications in the basal acid secretion from isolated whole rat stomach. The first three purine derivatives, ATP, ADP and AMP significantly increased the spontaneous acid secretion. On the other hand, AD caused a significant reduction in the basal acid secretion. When ATP, ADP, AMP and AD were assayed in the presence of the adrenergic and cholinergic blocking agents, ergotamine, 10(-6)M, propranolol, 5 X 10(-7)M and atropine, 10(-6)M, all these purine derivatives, including AD, caused a significant increase in the basal acid secretion.

Effect of the H1-histamine-like agonist material extracted from bovine spleen on 3': 5'-cyclic nucleotides content in guinea-pig ileal smooth muscle.

The effect of a water-soluble "histamine-free" splenic material that mimics the H1-receptor mediated contractile action of histamine on the guinea-pig ileum has been studied upon concentrations of cGMP and cAMP in slices of this smooth muscle preparation. The splenic extract induced a rapid and sustained decrease in the concentration of cGMP accompanied by a slow decrease in cAMP content in the ileal tissue. These results indicate that the smooth muscle-stimulating agent in splenic extract had no increasing effect on cGMP content as could be expected from the hypothesis that cGMP and cAMP might mediate the smooth muscle contraction and relaxation respectively. The data are not compatible with the general hypothesis that the action of histamine and histamine-like agonists on H1-receptors is associated with an increased concentration of cGMP.