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G Tancredi

Publications and source records attributed to G Tancredi.

At least 19 recordsLinked to original sources
PubMed2006

Charon's size and an upper limit on its atmosphere from a stellar occultation.

Pluto and its satellite, Charon (discovered in 1978; ref. 1), appear to form a double planet, rather than a hierarchical planet/satellite couple. Charon is about half Pluto's size and about one-eighth its mass. The precise radii of Pluto and Charon have remained uncertain, leading to large uncertainties on their densities. Although stellar occultations by Charon are in principle a powerful way of measuring its size, they are rare, as the satellite subtends less than 0.3 microradians (0.06 arcsec) on the sky. One occultation (in 1980) yielded a lower limit of 600 km for the satellite's radius, which was later refined to 601.5 km (ref. 4). Here we report observations from a multi-station stellar occultation by Charon, which we use to derive a radius, R(C) = 603.6 +/- 1.4 km (1sigma), and a density of rho = 1.71 +/- 0.08 g cm(-3). This occultation also provides upper limits of 110 and 15 (3sigma) nanobar for an atmosphere around Charon, assuming respectively a pure nitrogen or pure methane atmosphere.

Journal Article↗
PubMed2004

3-min step test and treadmill exercise for evaluating exercise-induced asthma.

A simple exercise test would be useful for detecting exercise-induced asthma, a common problem in asthmatic children. The current study compared the 3-min step test with treadmill exercise for evaluating exercise-induced asthma in asthmatic children and assessed whether responses to both tests are influenced by baseline lung function and habitual physical activity. A series of 154 asthmatic children (84 male children; mean age 12.9 +/- 0.9 yrs) underwent a 3-min step-test and treadmill testing on different days within a week at least 24 h apart. Before both tests each subject did spirometry to obtain the baseline forced expiratory volume in one second (FEV1). After both exercise challenges all subjects did serial spirometry and the lowest FEV1 recorded over time was used to calculate the fall in FEV1 expressed as a percentage of the measured pre-exercise (baseline) value (% fall in FEV1) and the area above the FEV1 curve (AAC0-30 min) expressed as a percentage of the pre-exercise value. Changes in both exercise variables were also analysed in percentile subgroups defined by questionnaire answers on habitual physical activity in hours. The mean % fall in FEV1 was significantly higher for treadmill exercise than for the step test (15.0 +/- 7.5 versus 11.7 +/- 5.9); and the AAC0-30 min was larger for treadmill than for the step test (-261.6 +/- 139.9% versus -197.3 +/- 105.0% min). In all subgroups defined by habitual physical activity the mean % fall in FEV1 decreased more after treadmill exercise than after the step test. After step test and treadmill exercise no significant correlation was found between % fall in FEV1 and baseline lung function, or between % fall in FEV1 among groups defined by habitual physical activity. Although the 3-min step test yields a lower % fall in forced expiratory volume in one second (FEV1) and a lower value of the area above the FEV1 curve than treadmill testing, it is a quick, economical, reproducible and portable alternative procedure for identifying exercise-induced asthma in outpatients and epidemiological studies. Baseline lung function and habitual physical activity have no influence on the amount or duration of exercise-induced asthma.

Adolescent↗
PubMed1996

Physical performance in patients with thalassemia before and after transfusion.

Patients with thalassemia who are on chronic transfusion programs have chronic ventilatory and cardiocirculatory abnormalities. We studied flow-volume curves, blood gas exchange, and cardiorespiratory responses to exercise in 12 patients with thalassemia major (TM) before and 24 hours after transfusions. Cardiorespiratory fitness was assessed with an exercise tolerance test on a cycle-ergometer. Ten healthy controls underwent the same protocol twice, first at baseline and then 24 hours later, without having had transfusions. We identified two subgroups of patients with a questionnaire: 1) those with no history of airway disease; and 2) those with a history of airway obstruction. Patients with no history of airway disease had normal baseline expiratory flows and no posttransfusion changes; those with a history of airway obstruction had lower pretransfusion expiratory flows rates and significantly decreased posttransfusion forced expiratory volume in 1 second (FEV1) and forced expiratory flow at 25-75% of forced vital capacity (FEV25-75%). As a group, TM patients had significantly lower pretransfusion cardiorespiratory function than controls; TM patients' maximum workload was 33% lower, maximum ventilation was 38% lower, maximum oxygen uptake was 25.7% lower, oxygen pulse was 28.6% lower, dyspnea index was 10.6% lower, and ventilatory equivalent for oxygen was 27.1% lower than in control subjects. Although cardiorespiratory responses to exercise improved in both subgroups after transfusion, patients with a history of airways obstruction had a significant posttransfusion increase in their dyspnea index (P = 0.05) and further increased their already abnormally high values of PETCO2 (43 mmHg). These results suggest that the transfusion worsened relative hypoventilation at the maximum workload only in the subgroup with a history of airway obstruction.

Adolescent↗
PubMed1994

[Cardiovascular adaptation to the stress test in subjects with Cooley's disease].

Thalassaemia major determines an impaired effort tolerance because of a condition of severe anaemia, progressive left ventricular dysfunction, pulmonary circulation compromise. The aim of our study is to evaluate haemodynamic response to exercise in thalassaemic patients without clinical features of heart failure. We have selected 13 patients affected by thalassaemia major (Thal+; 10-18 years). Each patient was transfused when haemoglobin values were < 9-9.5 g/dl and was treated with desferrioxamine (40 mg/kg sc) when serum ferritin values were > 2,000 ng/ml. Thal+ patients were compared with normal subjects (Thal- 10-16 years). No patient assumed hypotensive therapy, no had familiar history of hypertension. Both groups have undergone an ergometric stress test at the cycloergometer, with increase of 25 W every 2 min, up to the reaching of the maximum age-related heart rate, or up to muscle exhaustion or unbearable dyspnea, followed by a 10 min recovery phase. The following parameters were taken in consideration: systolic (SBP) and diastolic (DBP) blood pressure, heart rate (HR), the product of the heart rate by the systolic blood pressure (DP), at rest, at the maximum common work (MCW), at maximum stress and in the recovery phases. At rest, only DP showed significant differences between the two groups: in Thal+ patients higher than in Thal- (p = 0.045). At the MCW, Thal+ patients had SBP (p = 0.019), DBP (p = 0.01), HR (p = 0.035) and DP (p = 0.003) higher than Thal- patients. At maximum stress only DBP showed significant differences in Thal+ patients (p = 0.019), although Thal+ patients achieved lower levels of workload (p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1992

Enhanced allergic sensitisation related to parental smoking.

The objective of this study was to assess the role of parental smoking in changes, after a four year interval (1983-7), in the prevalence and severity of the atopic state in 166 pre-adolescent children. Allergy skin prick tests were related to parental smoking habits and their changes during this same interval. The total number of cigarettes smoked by parents decreased in 56 families while it increased in only 16. Boys had significantly more persistently positive skin tests and changed more frequently from negative to positive. The skin test index did not show significant changes in girls. This index did not change in children of persistent non-smokers or those starting to smoke during this period, while it increased among sons of those that quit smoking and of persistent smokers. This was not only due to those boys who became skin test positive during follow up. When analysis was restricted to 14 boys who had been skin test positive in 1983 and whose parents were persistent smokers, the index increased in eight, remained unchanged in four, and decreased in only two. This report supports the hypothesis that parental smoking is a factor that, together with specific allergenic exposure, may enhance allergic sensitisation in children.

Child↗
PubMed1988

Scanning electron microscopy of rabbit tubes at different intervals after anastomosis using fibrin glue.

Eighteen New Zealand White rabbits were submitted to tubal anastomosis using fibrin glue. The animals were then killed at different intervals (2-56 days) and the tubes were removed for analysis with the scanning electron microscope in order to study re-epithelialization and ciliogenesis. For the first 4 days after the operation the epithelium seemed to suffer considerable traumatic effects and was de-epithelialized. On the 6th day cells with microvilli appeared and towards the 10th day the first cilia were seen. Ciliogenesis was complete between 2 and 4 weeks after the operation, at which time the cilia re-acquired the ability to beat in coordination, as well as attaining normal quantity and length. The time required for recovery by the epithelium after anastomosis with fibrin glue would thus seem similar to that required when other suture materials are used. Fibrin glue thus combines the advantage of a considerable reduction in operating times with the ability to be rapidly reabsorbed, with complete restitutio ad integrum of the tissues.

Anastomosis, Surgical↗
PubMed1987

A prostaglandin analogue (ONO-802) in treatment of missed abortion, intrauterine fetal death and hydatiform mole: a dose-finding trial.

Forty-eight patients affected with missed abortion, intrauterine fetal death and hydatiform mole were treated with vaginal suppositories containing 1 mg of 16,16-dimethyl-trans-delta 2-PGE1 methyl ester (ONO-802). The patients were divided into two treatment groups. The first, Group A, was given one vaginal suppository every 3 h to a maximum of five suppositories. The product of conception was expelled in 95.8% of patients. In Group B the maximum number of suppositories was reduced to three. The product of conception was expelled in 100% of cases and the average duration of treatment was similar to that for the first group. Although side-effects were mild in both groups, they were reduced in the patients of Group B.

Abortifacient Agents↗
PubMedDate not supplied

[Clinical and neurophysiologic study of Guillain Barré syndrome: results of therapy with plasmapheresis].

The Guillain Barré poliradicoloneuritis shows a high incidence of permanent sequelae and exitus. Recently the plasmapheresis has been applied in the acute stage with a beneficial effect to the rapidity and the degree of the recovery. In the present study the results obtained in a group of patients with Guillain Barré of maximal severity are reported. All the patients have received plasmapheresis (3-5 exchanges) in the first days of the disease. Eventual side effects during the procedure have been evaluated together to the neurophysiological findings. The recovery has been evaluated in the brief and in the long term. From this study the efficacy of the plasmapheresis in Guillain Barré poliradicoloneuritis is confirmed. Furthermore a correlation has been evidenced between the amplitude of the muscular potential (CMAP) registered in the acute phase and the prognosis of the illness.

Adolescent↗
PubMedDate not supplied

Polydioxanone in anastomosis of rabbit tubes. A morphological study of the epithelium.

Eight NZW rabbits were submitted to end-to-end tubal anastomosis using polydioxanone (PDS), (Ethicon). The animals were sacrificed at two-week intervals between the second and sixteenth week after operating. The tubes were removed and analysed with the scanning electron microscope for the purpose of studying the morphology of the epithelium. Ciliogenesis was completed between the second and fourth weeks. After this period the epithelial conditions observed were completely normal, except for an abundant mucous secretion which, however, was totally normal after sixteen weeks.

Animals↗
PubMedDate not supplied

[Measurement of the metabolic response to physical exercise in children. Influence of training and bronchospasm].

A treadmill incremental exercise test was performed on 30 children. They were 18 healthy subjects (17 males, 1 female, age 7-16 years) and 12 asthmatic subjects (10 males, 2 females, age 9-19 years). The latter were characterized by exercise induced asthma (E.I.B.) and underwent a second test after the administration of Beta 2-adrenergic drug. During the test, while increasing the work-load, measurements were made of ventilation, O2 uptake CO2 production and heart-rate. No significant difference was found comparing the performances of the healthy subjects with those of the asthmatic patients. On the contrary trained subjects (both healthy and asthmatic) showed a better performance when compared to untrained subjects. In the presence of E.I.B. only untrained asthmatic children had their performances diminished. It is concluded that adequate information is required in order to avoid the negative consequences of exercising in the asthmatic subjects: physical exercise can be freely practised by children with asthma but they should be educated to recognize the limitations the bronchospasm can possibly represent for them.

Adolescent↗
PubMedDate not supplied

[Status asthmaticus].

Through a careful examination of the up-to-date literature on the subject, the Authors provide a full account of the present knowledge about the physiopathology of the status asthmaticus; at the same time they draw a practical exhaustive guide to the treatment to be carried out in hospital. The work arises from the considerable increase of mortality rate, due to asthma, recorded in the last few years.

Adolescent↗