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Biomedical subjects

F Manfredini

Publications and source records attributed to F Manfredini.

13 recordsLinked to original sources
PubMed1999

Blood testing in biathlon: observation of hematocrit values during competitive periods 1994-1997.

The International Biathlon Union, through its own Medical Commission, has undertaken a three-year program aimed at identifying the hematocrit levels of athletes who participate in biathlons. The purpose was to check for hematocrit levels exceeding normal physiological values as well as for any significant modifications within individuals during the course of the competitive season. All of the athletes registered in international biathlon races were, therefore, subjected to venous blood sampling (1 cc) three times a year prior to competition, in the days preceding two World Cup races (December and January) and the World Championships (February). The blood was centrifuged, the micro-hematocrit determined, and the value (rendered anonymous) recorded. This procedure was repeated for three consecutive competitive seasons (Dec. 1994-Feb. 1995, Dec. 1995-Feb. 1996, Dec. 1996-Feb. 1997). During this three-year period, the collected data showed a significant lowering of the average hematocrit level. In fact, from the first February sampling to the third February sampling, the average hematocrit value for the male population dropped from 48.04 +/- 2.36 to 46.33 +/- 1.91, and for the female population from 44.05 +/- 2.44 to 42.52 +/- 1.92. Even the distribution of the absolute hematocrit values was modified from the first to the third competitive season, especially for the February sampling, with a > or = 50% reduction for males and a > or = 48% reduction for females.

Adolescent↗
PubMed1999

The power output/heart rate relationship in cycling: test standardization and repeatability.

PURPOSE: The purpose of this study was to update and standardize the test for determining the power output/heart rate (PO/HR) relationship in cycling. METHODS: The current protocol was developed in the laboratory using a wind-load cycling simulator. Five hundred incremental tests were carried out by 290 male cyclists during a 2-yr period (1995-1997). The subjects' own bicycles, equipped with a standard crankset with a built-in power measuring system, were used for testing. The test protocol consisted of time-based increments in cadence that were uniform up to submaximal speeds and progressively greater in the final phase. RESULTS: The PO/HR relationship obtained was linear at low to submaximal PO and curvilinear from submaximal to maximal PO. A method was developed for the mathematical identification of the point of transition from the linear to the curvilinear phase (deflection point or heart rate break point). In 484 of the 500 tests performed, the deflection was independent of the final acceleration (PO at deflection 318.4 +/- 42.4 W, PO at final acceleration 351.6 +/- 43.2 W, P < 0.001), whereas in 16 tests the deflection and the start of the final acceleration coincided. To evaluate test repeatability and precision, 15 subjects repeated the test twice within a few days. No significant differences were found for the heart rate at deflection, power output at deflection, or slope of the linear part of the PO/HR relationship obtained in the two tests. CONCLUSION: It is concluded that the deflection point obtained by determining the PO/HR relationship on a wind-load simulator is not an artifact dependent on the incremental test protocol but rather a repeatable physiological phenomenon.

Adolescent↗
PubMed1998

Circadian rhythms, athletic performance, and jet lag.

Rapid air travel across several time zones exposes the traveller to a shift in his/her internal biological clock. The result is a transient desynchronisation of the circadian rhythm, called jet lag, lasting until the rhythm is rephased to the new environmental conditions. The most commonly experienced symptoms are sleep disorders, difficulties with concentrating, irritability, depression, fatigue, disorientation, loss of appetite, and gastrointestinal disturbance. Apart from the decrements in mental and physical performance directly consequent on such symptoms, competitive athletes are also exposed to the additional negative consequences of a shift from the optimal circadian window of performance. A brief summary of the possible negative effects of jet lag on athletic performance and potentially alleviating strategies is given.

Adaptation, Physiological↗
PubMed1996

The Conconi test: methodology after 12 years of application.

The protocol for the determination of the speed/heart rate relationship during incremental exercise previously described (so-called Conconi test) has been refined and in part modified during 12 years of application. The new protocol calls for time-based increments in exercise intensity that are uniform up to submaximal speeds and progressively greater in the final phase. As in the original article (18), the speed/heart rate relationship is linear at low to moderate speed and curvilinear from submaximal to maximal speeds. A method is presented for the mathematical definition of this relationship, with the calculation of the straight-line equation of the linear phase and the identification of the point of transition from the linear to the curvilinear phase (deflection point or heart rate break-point). Analysis of 300 tests selected at random from those in our data base (more than 5,000 tests) has enabled us to show that the speed at which the deflection point occurs is significantly lower (p < 0.001) than that at which the acceleration of the final phase begins. This fact demonstrates that the break-point is not brought on by the final acceleration called for in the test protocol. Analysis of the speed/heart rate relationship allows for the determination of the following additional functional indices: 1) maximal heart rate (in 21 athletes the maximal heart rate attained in the test and that attained while racing were equal); 2) range of heart beats defining the linear part of the speed/heart rate relationship; 3) range of heart beats from the deflection point to maximal heart rate; and 4) maximal aerobic exercise intensity, obtained through extrapolation of the straight-line equation to maximal heart rate. Data are provided on the conditions of the test subject that modify his speed/heart rate relationship, such as incomplete recovery from previous efforts, inadequate warm-up, or inadequate test procedure with too rapid increments in exercise intensity. Finally, criteria for test acceptability are presented.

Adolescent↗
PubMed1996

Reproducibility of the Conconi test: test repeatability and observer variations.

The repeatability of the the speed/heart rate (S/HR) relationship obtained with the incremental test developed by Conconi et al. (5) was examined by having 75 subjects perform the same running test twice in the course of a few days. From the data obtained, comparisons were made of four variables: 1) speed of deflection, 2) heart rate of deflection, 3) slope, and 4) intercept on the y-axis of the linear portion of the S/HR relationship. Straight-line equations, correlation coefficients (r), and technical errors of measurement (TEM) were obtained by comparing data from the two successive tests. Data analysis suggests that in two successive tests there are some variations in the linear portion of the S/HR relationship. However, the straight lines obtained from the two tests converge at the same deflection point. The problem of assigning a single value to the point of deflection, when determined by means of visual analysis of the S/HR graph, was also examined. For this part of the study, speed and heart rate data previously obtained for 65 subjects were used. The selected tests had been carried out during the course of various studies. The 65 sets of test data were plotted on graph paper and given to six observers for independent evaluation of speed and heart rate of deflection. These observers had different levels of experience in interpreting Conconi test results. The speed and heart rate of deflection values assigned by each observer were compared to the values obtained through mathematical analysis of the tests by computer. Straight-line equations, correlation coefficients (r), and technical errors of measurement (TEM) obtained by comparing visually determined data to those determined through mathematical analysis were calculated for each observer. Only for observers with little experience were some differences found between the observer-assigned and computer-determined results; these differences occurred for both speed and heart rate of deflection. We conclude that visual analysis provides information that is very similar to that obtained through computer analysis. The accuracy of the visually obtained information varies according to the observer's experience.

Adult↗
PubMed1996

[Light-guided intubation using Trachlight].

BACKGROUND: A new intubating transilluminated device (Trachlight) has been recently proposed as an alternative to tracheal intubation with direct laryngoscopy. OBJECTIVE: 1) To evaluate Trachlight device in orotracheal intubation and to assess its operation and complications. 2) To compare the time consumption of transillumination intubation in respect to direct laryngoscopy on the same patients. METHODS: The first study was performed on 50 patients undergoing elective surgery and submitted to Trachlight intubation alone; speed of intubation, number of attempts and all complications were recorded and related to Mallampati classes. In the second study 16 patients undergoing to elective surgery were enrolled. Each patient was classified according to both the Mallampati classes and the Cormack classes. Each patient was submitted to two tracheal intubations: the first with the Trachlight and the second with conventional direct laryngoscopy performed by the same anesthesiologist. The time to intubation and the number of attempts were recorded and related to the Mallampati and Cormack classes. RESULTS: In the first study time of intubation with Trachlight was 20.93 +/- 13.02s (mean +/- SD) without statistical differences in respect to the Mallampati classes. In the second study the times to intubation were without any statistical difference independently of the technique of intubation and of the Mallampati or Cormack classes. CONCLUSIONS: Orotracheal intubation using Trachlight appears to be an effective and easy to learn technique, being also easy, safe and fast to carry out. The comparison with direct laryngoscopy showed the same speed and effectiveness even on patients with difficult intubation.

Adolescent↗
PubMed1995

Relationship between physical activity level and bone mineral density in two groups of female athletes.

In order to evaluate the possible relationships among hormonal status, physical activity and bone density, we carried out a study on two groups of female athletes engaged in different levels of physical activity. We measured the following hormones: luteinizing hormone (LH), folliculo-stimulating hormone (FSH), 17-beta-oestradiol (E2), progesterone (PRG), prolactin (HPRL), estrone (E1), thyreo-stimulating hormone (TSH), free thyroxine (FT4), and the markers of phosphate-calcium metabolism: calcitonine (CT), parathormone (PTH), and osteocalcine (BGP). We also measured bone mineral density (BMD). All of these variables were related to the amount of work performed during training. The groups were defined as follows: medium workload (group M, n = 10) and heavy workload (group H, n = 20), engaged in 10 and 18 hours of weekly training at 35 and 60 average percent of VO2max, respectively. All of the hormones and the markers of calcium-phosphate metabolism studied were normal; BMD was also normal for all subjects except for two sisters in group M with reduced BMD. The group H athletes with regular menstrual cycles were found to have an upper limit normal BMD. From these data we conclude that in regularly menstruating athletes an increase in BMD induced by heavy physical activity is evident, while in dysmenorrhoeic athletes the effect of physical activity compensates, to some extent, for the hypothetical bone mineral reduction possibly caused by the hormonal imbalance.

Aged↗
PubMed1993

Hematological indices of erythropoietin administration in athletes.

Recombinant human erythropoietin (EPO), commercially available since 1988, is thought to be used by athletes in aerobic sports for the purpose of increasing oxygen transport and aerobic power. In an attempt to identify EPO administration, we have studied the peripheral blood of 20 subjects practising sports at an amateur level. Automated cytometry was performed on the blood samples before and during 45 days of EPO treatment. The same hematological indices were determined for a control population that consisted of 240 elite athletes from various sports. As expected following EPO treatment, RBC, [Hb] and Hct increased significantly (increments of 8%, 6.3% and 11%, respectively). A significant increase in reticulocyte count was also observed. In addition, automated erythrocyte analysis showed a significant increase in cells with a volume > 120 fl and hemoglobin content (HC) < 28 pg (hypochromic macrocytes, or MacroHypo): 0.06 +/- 0.09% before EPO, 0.48 +/- 0.63% after EPO. The EPO-treated subjects differed from the control population having higher values for Hct, mean corpuscular volume (MCV), Macro and MacroHypo. To investigate the possibility of using such variations in blood parameters to identify EPO treatment, individual values for Hct, MCV, Macro and MacroHypo for treated subjects and controls were plotted. Using the percentages of MacroHypo, a cut-off value surpassed in approximately 50% of the treated subjects and in none of the controls was established.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Reduction of Hb levels during the racing season in nonsideropenic professional cyclists.

Hematological variables of 40 professional cyclists, all receiving intravenous iron supplementation, were followed during a 15-month period. Mean values for red blood cells (RBC), hemoglobin (Hb), and hematocrit (Ht) were significantly lower during the racing season (RS) than during the nonracing periods (NRP) (RBC: RS = 4.53 +/- 0.34 millions/mm3, NRP = 5.09 +/- 0.36 millions/mm3; line 7 of abstract: Hb: RS = 14.2 +/- 0.9 g/dl, MRS = 15.2 +/- 0.9 g/dl; Ht: RS = 40.7 +/- 2.7% NRP = 44.4 +/- 2.9%; P less than 0.001 for all). However, mean values for ferritin and mean corpuscular hemoglobin (MCH) were significantly higher during the racing season (ferritin: RS = 422 +/- 398 ng/ml, NRP = 311 +/- 321 ng/ml, P less than 0.05; MCH: RS = 31.5 +/- 1.3 pg, NRP = 30.0 +/- 1.4 pg; P less than 0.001). These results suggest that the reductions in RBC, Hb, and Ht found in professional cyclists during the racing season are not the consequence of a diminution of iron stores but rather of reduced erythropoiesis and increased RBC destruction.

Anemia, Hypochromic↗
PubMed1987

Chronobiologic aspects of recurrent transient ischemic attack.

An epidemiologic study was conducted from 1979 through 1984 on subjects presenting transitory ischemic attacks (TIA) and admitted into our Institute. We investigated year, season, month, day, and hour of every attack on 80 patients aged between 51 and 88 years. Time-series analysis showed a seasonal pattern of disease onset in early spring. Peaks occurred in March-April, and isolated peaks were also detected in January and October. Concerning TIA-onset day, we observed a peak distribution in the last 10 days of the month. Data on the hour of onset, according to single cosinor (mesor +/- SE = 2.67 + 1.13; amplitude +/- SE = 2.57 + 1.13), yielded a significant (P less than 0.05) acrophase. The acrophase is at -135 degrees (-93 degrees, -245 degrees) for tau = 48 hr.

Aged↗