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Today, approximately 40 percent of all treated cases of breast cancer involve small (less than 2 centimeters, or three-quarters of an inch) tumors. This is due to early detection, and has resulted in development of techniques designed to save as much of the breast tissue as possible. In 1981, results were reported using the QUART technique, which is conservative surgery involving excision of only that quadrant of the breast which contains the tumor, removal of the lymph nodes in the axilla, and radiation therapy. These results showed survival rates using the QUART technique that were comparable to those of patients who had undergone radical mastectomy (removal of the entire breast, underlying muscle, axillary lymph nodes and all adjacent fat, fascia and other tissue). Results are reported in this article of 1,232 women with cancerous tumors of less than 2 cm who were treated with QUART therapy. The overall survival rate at five years after surgery was 91 percent, and at 10 years, 78 percent. Probability of survival tended to decrease as the size of the tumor increased; the seven-year survival for patients with tumors 1.6 to 2 cm was 84 percent, compared with 94 percent for patients with tumors under 0.5 cm. Patients who had more than one lymph node involved in the cancer process showed a lower probability of survival (79 percent at seven years). There were 45 cases of cancer that developed in the opposite breast during the period of follow-up (averaging 72 months). The incidence of recurrence in the QUART-treated breast was 2.8 percent (35 patients), and the incidence of a new primary tumor in that breast was 1.6 percent (19 patients). These patients underwent a second operation; five died and 49 are still alive. The low rate of recurrence in the QUART-treated breast is remarkable. It appears that local recurrence after QUART does not have as great an affect on long-term survival as does local recurrence following more traditional surgery. The heavy irradiation of the breast does not appear to have increased the risk of new cancers within 10 years of treatment. (Consumer Summary produced by Reliance Medical Information, Inc.)

AbstractThis study reports the tolerability and feasibility of capecitabine, an oral fluoropyrimidine, chemoradiation as postoperative treatment. Stage II-III rectal cancer patients received 2 cycles of bolus 5-FU (425 mg/m2) and leucovorin (LV) (20 mg/m2) on days 1-5 q3w followed by oral capecitabine (800 mg/m2bid) continuously during pelvic radiotherapy (total 50.4 Gy). Two additional cycles of 5-FU/LV were finally administered.Forty-one radically resected patients (median age: 61 years) were enrolled. All patients were evaluable for safety. Grade 3 adverse events included: proctitis (n = 3, 7%), diarrhea (n = 5, 12%), and leukopenia (n = 1, 2%). The overall rate of grade 3 diarrhea and leukopenia was 15% (95% confidence interval, 5-29%).Capecitabine chemoradiation in the adjuvant setting is well tolerated and is convenient to administer. These results support the use and further study of capecitabine chemoradiation in radically resected rectal cancer patients.

Abstract: Using linear stability analysis, the qualitative stability properties of open nonlinear chemical systems, in which reactions of any order may occur, will be studied. Systems will be classified in three fundamental classes: trees, cycles and loops, according to their knot graphs. The study of the Jacobian matrix for the kinetic equations of the system shows that the symmetrizability by a particular procedure (calledD-symmetrizability) is a sufficient condition for stability. It has been proved that tree-graphs always satisfy the above condition. For the cycle-graphs, theD-symmetrizability condition leads to a cyclic relation between forward and reverse steady state flows. The stability may be assured, even if the cyclic relation is not satisfied, providing that the “symmetry breaking” be lower than an upper bound; further alternative criteria for stability of cycles have been derived. All these results are independent of the number of diffusive exchanges with the environment.

The growth of a species feeding on a limiting nutrient supplied at a constant rate is modelled by chemostat-type equations with a general nutrient uptake function and delayed nutrient recycling. Conditions for boundedness of the solutions and the existence of non-negative equilibria are given for the integrodifferential equations with distributed time lags. When the time lags are neglected conditions for the global stability of the positive equilibrium and for the extinction of the species are provided. The positive equilibrium continues to be locally stable when the time lag in recycling is considered and this is proved for a wide class of memory functions. Computer simulations suggest that even in this case the region of stability is very large, but the solutions tend to the equilibrium through oscillations.

A sufficient condition for the existence of a globally asymptotically stable equilibrium in Volterra models with continuous time delay is obtained, and some properties of the stable equilibrium are proven. Furthermore, some applications in which asymptotic stability only depends on the sign of the coefficients are considered.

During the period of 1984-1986, the authors have implanted 13 poly tetrafluoroethylene (PTFE) bifurca tion grafts for the treatment of aor toiliac occlusive disease. The patients were 12 men and 1 woman, their mean age being 60.5 ± 6.3 years. The indi cations for aortoiliac reconstruction were limiting claudication in 6 pa tients and rest pain in 7 patients. Follow-up lasted forty-six ± seven months and included physical exami nation, measurement of the ankle- brachial pressure index, and ultra sonography. Arteriography was per formed exclusively in symptomatic patients. No operative deaths or major complications were recorded. Graft limb occlusion occurred in 2 patients, eight and twenty-two months after surgery, respectively. The five-year patency rate was 85 % . During follow-up, there was no evi dence of graft infection, kinking, stenosis, or dilatation. Neither peri- graft seroma nor anastomotic aneu rysm developed.

Postanoxic myoclonus was first accepted as being related to a dysfunction of the ventrolateral thalamic nucleus. Several stereotaxic studies have invalidated this hypothesis. The neurochemical approach, in particular the measure of 5-hydroxyindolacetic acid in the cerebrospinal fluid, has opened new theoretical and therapeutic possibilities involving serotoninergic pathways.

The paper contains an extension of the general ODE system proposed in previous papers by the same authors, to include distributed time delays in the interaction terms. The new system describes a large class of Lotka-Volterra like population models and epidemic models with continuous time delays. Sufficient conditions for the boundedness of solutions and for the global asymptotic stability of nontrivial equilibrium solutions are given. A detailed analysis of the epidemic system is given with respect to the conditions for global stability. For a relevant subclass of these systems an existence criterion for steady states is also given.

We study a system of two integrodifierential equations which models the evolution of a biotic species feeding on an abiotic resource. We also consider nutrient recycling with time delay. By Hopf bifurcation theory we prove the existence of stable oscillations for a range of values of the input of nutrients.

The merits of isolated profundaplasty remain controversial, because of many variables in patient selection and operative technique, including or not concomitant inflow procedures. This report deals with a homogeneous group of 11 male patients, aged forty-seven to seventy-two years, who underwent isolated profundaplasty for limb salvage and were thereafter available for follow-up. The check-up protocol included echographic examination of the femoral region, in order to detect any aneurysm formation of the reconstructed vessel. A fe morodistal bypass was judged unsuitable in all cases, because of severity of the atherosclerotic disease involving popliteal and tibial arteries. The cumulative limb salvage rate was 63% at two years and 54% at five and ten years. Five reconstructions failed within four years after surgery. Four patients died two to eight years following profundaplasty. An aneurysm of the reconstructed pro funda femoris artery was diagnosed in 1 patient three years after surgery. Ten months later the patient presented with a gangrenous forefoot and underwent below-knee amputation. In conclusion, isolated profundaplasty may achieve an acceptable limb salvage rate, even in patients with a poor distal vascular bed. Ectasia of the reconstructed profunda artery represents a potential, serious complication.

Abstract: In this paper we consider the stability property of single-species patches connected by diffusion with a within-patch dynamics of Volterra type and with continuous time delays. We prove that this system can only have two kinds of equilibria: the positive and the trivial one. By the assumption that the delay kernels are convex combinations of suitable non-negative and normalized functions, the linear chain trick gives an expanded system of O.D.E. with the same stability properties as the original integro-differential system. Homotopy function techniques provide sufficient conditions for the existence of the positive equilibrium and for its global stability. We also prove the local stability of any positive equilibrium and the local instability both of positive and trivial equilibria. The biological meanings of the results obtained are compared with known results from the literature.

Abstract: The problem of optimal dosage is studied for the administration of ddCyd using erythrocytes as carriers and bioreactors. The volume of erythrocytes and the initial amount of drug to be loaded have to be determined in such a way that the duration of the therapeutic effect is maximized without exceeding the toxic threshold. It is found that the optimal control is unique and it is at the upper vertex of the set of the admissible controls. A more general case is also briefly discussed.

Abstract: We introduce a graphical approach in the study of the qualitative behavior ofm species predator-prey systems. We prove that tree graphs imply global stability for Volterra models and local stability for general models; furthermore, we derive sufficient conditions so that loop graphs imply stability and boundedness of the solutions.

Lo studio della distribuzione nel tempo degli intervalli fra gli impulsi offre un modo di separare gli impulsi spuri dovuti ad emissione secondaria dal catodo da quelli eventuali dovuti ad altre cause. In questa nota si mostra come si possa per questa via giungere a una determinazione del coefficientekdi liberazione d'elettroni alla superficie da parte degli ioni che vi pervengono, almeno nei contatori cosidetti rapidi. Si assegnano i valori dikper superficie di metallo e di vetro colpite da ioni molecolari d'alcool etilico.

Lo studio sistematico dei contatori in vetro a catodo esterno ci ha portati alle conclusioni seguenti. I contatori a miscela di argon ed alcool si comportano come gli analoghi contatori a catodo esterno per valori limitati dell'intensità di radiazione (2÷3 particelle per cm2e per sec e per unità di angolo solido): oltre questo valore la salita del potenziale interno fa perdere via via un numero sempre maggiore di impulsi. I contatori riempiti con gas a molecola semplice puri si comportano solo apparentemente come contatori a miscela: lo spegnimento della scarica dopo un impulso ha lugo per effetto della salita del potenziale interno ed il tempo morto apparente dovuto al processo di scarica della parete interna risulta dell'ordine di 10−1sec.

The aim of our study was to evaluate the best method for cervical ripening before a classical induction with amniotomy and oxytocin. One hundred term pregnant patients who presented an unfavorable cervix and an indication for the induction of labor were assigned randomly to either 0.5 mg prostaglandin (PG) E2 gel intracervically (N52) or 3 mg FGE2 gel intravaginally (N48). The intravaginal gel had a greater effect on cervical ripening according to a modification of the Bishop score than did intracervical gel, but it had a higher incidence of side effects.