Biomedical subjects
Publications and source records attributed to S Invernizzi.
The Authors report a case of inguinal bladder hernia and briefly refer about the different kinds of this rare pathology which is often associated to the commonest inguinal hernia. They, moreover, point out the surgical treatment which has to aim to the repositioning of the bladder and to solve the cervicovesical obstruction.
We study, from a quantitative point of view, the Hopf bifurcation in an ODE model of feedback control type introduced by Goodwin (1963) to describe the dynamics of end-product inhibition of gene activity. We formally prove that the exchange of linear stability of the positive equilibrium in the n-dimensional Goodwin system with equal reaction constants coexists with a Hopf bifurcation of nontrivial periodic solutions emanating from this equilibrium, without any further restriction on the dimension n greater than or equal to 3 or on the Hill coefficient. The direction of the bifurcation and the stability and the period of the bifurcating orbits are estimated by means of the algorithm proposed by Hassard et al. (1981).
During the last 15 years the Dormia stone dislodger has been used in 352 cases (80%) out of 435 of ureteral stones: 318 were at ileo pelvic, 34 at lumbar level. 303 ileo pelvic and 21 lumbar stones have been successfully removed (92%). Considering that the probability of stone removal is directly proportional to the ureteral expansibility and indirectly proportional to the volume of the stone, the Basket technique isn't indicated: When the stone is more than 1 cm.; When the ureter is widely stiff (as in Ormond d. or post-radiotherapy stiffness); When stenosis is present. The impossibility of bypassing the stone, the insufficient expansion of the Basket, the stone irremovability and the difficult extraction through the meatus, my limit the successes of this technique while iperating. The immediate complications have been: 4 sectoral rips of the mucosa surrounding the ureteral end, cured by catheterisation without aftereffects (1.2%); 1 sliding of the ureter through the trigone up to urethral meatus (in a woman), which has been repaired, without aftereffects, by direct catheterisation of the ureter, out of the urethra, after removal of the Basket and stone from the ureteral extremity. (0.3%) Strictures occurred in 5 cases (1.5%) and vescicoureteral reflux in 6 (1.8%). These results of the sole Basket technique (performed according to the well-known directions) seem to be much better than those (which have been illustrated) obtained with the endoscopic lithotripsy.
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The use of high doses (15-20 Gy) of X- or gamma-rays to irradiate blood-derived materials is a common practice by now. It is usual especially when materials must be transfused into non-immunocompetent patients. This is done to avoid the so-called GVH disease. Nowadays, for this purpose, units containing radioactive gamma-emitting sources with high activity and long half-life (usually 137Cs) are on the market. The characteristics of these "irradiators" allow their implementation in any laboratory with no need of structural shieldings. In spite of it, serious accidents (e.g., fire, fallings, etc.) which could imply hazards for the operating staff and even the general population, cannot be excluded. At the same time, the problem of long-term disposal of exhausted sources cannot be neglected. For these reasons, a new type of self-shielded irradiator was designed. It is equipped with an X-ray tube, operating at nearly 200-kV voltage, with 12-mA anodic current. The system is water- and oil-cooled and can work for a long time without thermal overloads. In this paper, the environmental and dosimetric measurements for beam characterization are reported. The system can produce beams with satisfactory characteristics for this specific problem. Moreover, its use may greatly reduce administrative radioprotection problems.