Biomedical subjects

F Arrigoni

Publications and source records attributed to F Arrigoni.

3 recordsLinked to original sources

PubMed2002

Limits of a multi-patch SIS epidemic model.

We start from a stochastic SIS model for the spread of epidemics among a population partitioned into M sites, each containing N individuals; epidemic spread occurs through within-site ('local') contacts and global contacts. We analyse the limit behaviour of the system as M and N increase to infinity. Two limit procedures are considered, according to the order in which M and N go to infinity; independently of the order, the limiting distribution of infected individuals across sites is a probability measure, whose evolution in time is governed by the weak form of a PDE. Existence and uniqueness of the solutions to this problem is shown. Finally, it is shown that the infected distribution converges, as time goes to infinity, to a Dirac measure at the value x(*), the equilibrium of a single-patch SIS model with contact rate equal to the sum of local and global contacts.

Animals↗

PubMed1995

[Epidemiological behavior of perforated peptic ulcer before and after the introduction of the antisecretory drug therapy. Our experience].

The diagnostic iter and treatment of peptic ulcer have evolved considerably over the past 20 years. The capillary spread of endoscopy has permitted secure and precise diagnoses to be made, in terms of both the site and size of the anatomic lesion, on the one hand, and on the other, the introduction of antisecretory drugs has led to the resolution of the majority of ulcers, so much so that the ulcer is no longer managed using strictly surgical methods but is now treated medically and only emergency cases, such as perforations, undergo surgery. Complications, such as digestive hemorrhage, penetration and stenosis, may lead to the need for surgery. In particular, perforation seems to be the only complication which has not been significantly influenced by the introduction of antisecretory therapy, the point that its status as a "complication" has been questioned leading to the suspicion of its nosological autonomy. The authors review the series of ulcer patients admitted to hospital during the period 1968 to 1991, paying special attention to the correlation with the use of antisecretory drugs which were introduced during the period 1978-1981, the trend of ulcer complications over the entire period, the duration of symptoms and the epidemiology of peptic and perforated ulcers.

Aged↗

PubMed1993

[Quandrantectomy in the conservative treatment of breast carcinoma].

Two years after the first evaluation, the authors review the results of quadrantectomy in the conservative treatment of breast carcinoma. Local control of the disease by quadrantectomy with axillary lymphadenectomy and radiotherapy has been more difficult in the T2 patients (4 local relapses out of 41 patients) compared T1 patients (3 local relapses out of 52 patients). Nodal involvement appears to be not crucial for the prognosis (7 patients out of 10 with remote metastases were N- at the time of surgery).

Antineoplastic Combined Chemotherapy Protocols↗