Biomedical subjects

P Rolla

Publications and source records attributed to P Rolla.

5 recordsLinked to original sources

PubMed2002

Relaxation processes in an epoxy resin studied by time-resolved optical Kerr effect.

The dynamics of the epoxy resin phenyl glycidyl ether, a fragile glass-forming liquid, is investigated in the liquid and supercooled phases by time-resolved optical Kerr effect experiment with an heterodyne detection technique. We tested the mode-coupling theory and found that the predicted dynamic scenario allows to reproduce properly the measured signal, for t>1 ps, in the whole temperature interval investigated. Furthermore, the values of T(c) and lambda, obtained from the analysis of three different and independent dynamic regimes (alpha regime, von Schweidler, beta regime), are in remarkable agreement. Moreover, relaxation times obtained from optical Kerr effect and dielectric spectroscopy measurements are compared. The two time scales differ only for a constant factor in the whole temperature interval investigated.

Journal Article↗

PubMed1994

Reversibility of the inhibitory effect of salmon calcitonin on bone resorption in rats.

Inhibition of osteoclastic bone resorption has been induced in growing rats with high doses of salmon calcitonin. This effect was evaluated by measuring the perichondrial ring height of the proximal tibial metaphysis. The aim was to assess whether osteoclastic activity resumed after a period of inhibition with high doses of calcitonin. 20 male Sprague-Dawley rats were treated for 21 days with 100 units/kg/day of salmon calcitonin subcutaneously and killed after 0-60 days, together with non-treated controls at 0 and 60 days. Arrest of metaphyseal modeling and increased height of the perichondrial ring at the end of the period of therapy (P 0.002 versus controls) were observed. Recovery of bone resorption was evident 20 and 40 days after withdrawal of calcitonin.

Animals↗

PubMed1992

Treatment of slipped capital femoral epiphysis: evaluation of the results of extracapsular epiphysiodesis and open reduction-epiphysiodesis.

The authors review 26 patients who underwent either "in situ" extracapsular epiphysiodesis or intracapsular reduction followed by epiphysiodesis for slipped capital femoral epiphysis (SCFE). A total of 32 operations were performed. In the first group (chronic grade II SCFE), no complications occurred in the 16 operations and the results were excellent in all cases. In the second group (chronic grade II and III SCFE and acute-on-chronic SCFE), in 16 operations we observed four cases of avascular necrosis, two of which accompanied by chondrolysis. Three of these were in cases of acute-on-chronic SCFE. The results confirm that the cases of acute-on-chronic SCFE have the worst prognosis and a much higher risk of avascular necrosis and/or chondrolysis than purely chronic SCFE. Early diagnosis of ischemic complications make it possible to maintain the spherical shape of the femoral head and good joint function. The results are considerably better than in untreated cases.

Adolescent↗

PubMed1992

[The direct and computed radiographic assessment of vertebral locations in children with acute lymphatic leukemia].

The children affected with acute lymphoblastic leukemia (ALL) often exhibit secondary lesions of the spine. The diagnosis of spinal involvement is currently made by means of conventional radiography in postero-anterior and lateral views. The osteolytic lesions of the vertebral body present with collapse of the vertebral plates in a wide range of severity. Body evaluation is usually made by comparison with the adjacent vertebrae. Since leukemia is a systemic disease, several vertebrae are possibly involved in each case. In the attempt to develop a more sensitive method, which is less dependent on observers' evaluation, a quantitative and comparative analysis of vertebral bodies was performed. The radiographs in lateral view of the dorsal and lumbar spine of 14 children with ALL were analyzed: previous radiological reports suggested the lesion of one or more vertebral bodies. The area of each vertebral body was measured and digitalized by means of a backlighted graphic table and of a software developed to this purpose. The criteria to define the collapse of a vertebral body were the ratio between areas of adjacent vertebral bodies, in conformity to the anatomic and radiographic principle that, in the dorsal and lumbar spine, the body of a normal vertebra is equal to or bigger than that of the upper one. The data obtained by quantitative analysis were compared with conventional radiologic reports. A hundred and fifty-five vertebrae were analyzed by computerized analysis; 17 (10.9%) vertebrae, undetected at conventional analysis, were collapsed. This method allows a more precise diagnosis of collapsed vertebral lesions; its accuracy can be improved with further development of digital technology.

Adolescent↗

PubMed1991

[Stomatological problems related to pregnancy. A statistical study].

Pregnancy is related to particular dental issues, such as the increased incidence of diseases( gingivitis, caries, epulis), the fluoride supplementation, and the limits of diagnostics and therapy. Moreover, the mysterious halo surrounding pregnancy often makes the dentist uneasy. In order to objectively evaluate the implications of pregnancy in dentistry, we distributed a form to 100 pregnant women. The results of the form showed that 53 of them had gingival bleeding, 22 had toothache, 19 had caries but that just 12 of them had gone to the dentist because of dental troubles while 54 had not gone at all. Among the pluri-gravidae, all the women with dental diseases in their previous pregnancies had them again in their current pregnancy but nonetheless only some had undergone a dental check-up. The dentists did not show any uneasiness, as they performed tooth extractions in 5 women, endodontics in 2 women and fillings in 11 women. Just 4 out of 100 women had taken a fluoride supplementation. We deem advisable a stronger collaboration between physician, gynecologist and dentist in order to resolve specialist problems and to make pregnant women more aware of the need for dental follow-ups and fluoride supplementations.

Adult↗