BACKGROUND: Duodenal fistula (DF) after gastrectomy continues to be a life-threatening problem. We performed a retrospective multicenter study analyzing the characteristics of DF after elective gastrectomy for malignant disease. METHODS: Three thousand seven hundred eighty-five patients who had undergone gastrectomy with duodenal stump in 11 Italian surgical units were analyzed. RESULTS: Sixty-eight DFs occurred, with a median frequency of 1.6% and a mortality rate of 16%. Complications were mainly septic but fistulas or bleeding of surrounding organs accounted for about 30%. Reoperation was performed in 40% of patients. We observed a correlation between mortality and age (hazard ratio 1.09; 95% CI 1.00-1.20) and serum albumin (hazard ratio 0.90; 95% CI 0.83-0.99). The appearance of further complications was associated with reoperation (P < 0.001) and death (P = 0.054), while the preservation of oral feeding was related to DF healing (P < 0.001). CONCLUSIONS: This paper represents the largest series ever published on DF and shows that its features have changed in the last 20 years. DF alone no longer leads to death and some complications observed in the past have disappeared, while new ones are emerging. Nowadays, medical therapy is preferred and surgery is indicated only in cases of abdominal sepsis or bleeding.

A theoretical and numerically study of dynamical properties in the sol-gel transition is presented. In particular, the complex phenomenology observed experimentally and numerically in gelling systems is reproduced in the framework of percolation theory, under simple assumptions on the relaxation of single clusters. By neglecting the correlation between particles belonging to different clusters, the quantities of interest (such as the self intermediate scattering function, the dynamical susceptibility, the Van-Hove function, and the non-Gaussian parameter) are written as superposition of those due to single clusters. Connection between these behaviors and the critical exponents of percolation are given. The theoretical predictions are checked in a model for permanent gels, where bonds between monomers are described by a finitely extendable nonlinear elastic potential. The data obtained in the numerical simulations are in good agreement with the analytical predictions.

Amyloidlike proteins form highly organized aggregates, such as fibrils and plaques, preceded by the assembly of a wide range of unstructured oligomers and protofibrils. Despite their importance in a number of human neurodegenerative diseases, a comprehensive understanding of their kinetics and thermodynamics is still missing. We investigate, by computer simulations, a realistic model of amyloid molecules interacting via the experimentally determined Derjaguin-Landau-Verwey-Overbeek potential and derive its phase diagram. We show that fibrils and plaques, along with their precursors, correspond to different equilibrium and metastable thermodynamics phases and discuss the dynamical mechanisms leading to the nucleation and self-assembly of large scale structures.

BACKGROUND AND OBJECTIVES: The recurrence of hepatocellular carcinoma (HCC) after percutaneous ablation is poorly evaluated. METHODS: Thirty-six cases of recurrence after percutaneous ablation (PA)(Group 1) are compared to those after surgery, treated with re-resection (26 patients, Group 2) and PA (31 patients, Group 3). RESULTS: Recurrence was usually local after PA and distant after resection. Compared to Groups 2 and 3, local recurrences after PA were larger (4.2 vs. 2.3 cm) and more often invasive (43% vs. 10%). No different clinical/pathological aspects were noted in distant recurrences among the groups. After treatment the survival rate (1, 2, 3 and 5 years) was no different between the groups; in an intention-to-treat analysis of survival for local recurrences, survival was significantly lower in Group 1 (78%, 78%, 67% and 28%) than in Groups 2 and 3 (100%, 88%, 75% and 45%)(P < 0.05). CONCLUSIONS: PA and surgery can be sequentially employed for HCC. The type of primary treatment does not influence the features of distant liver recurrence, while local recurrence after PA often requires more extensive liver resection. J. Surg. Oncol.(c) 2009 Wiley-Liss, Inc.

We present a theoretical study of a system with competing short-range ferromagnetic attraction and a long-range antiferromagnetic repulsion, in the presence of a uniform external magnetic field. The interplay between these interactions, at sufficiently low temperature, leads to the self-tuning of the magnetization to a value which triggers phase coexistence, even in the presence of the external field. The investigation of this phenomenon is performed using a Ginzburg-Landau functional in the limit of an infinite number of order parameter components (large N model). The scalar version of the model is expected to describe the phase separation taking place on a cell surface when this is immersed in a uniform concentration of chemical stimulant. A phase diagram is obtained as a function of the external field and the intensity of the long-range repulsion. The time evolution of the order parameter and of the structure factor in a relaxation process is studied in different regions of the phase diagram.

BACKGROUND: The treatment of hepatic metastases from gastric cancer is controversial, due to biologic aggressiveness of the disease. OBJECTIVE: To survey the clinical approach to the subset of patients presenting with metachronous hepatic metastases as sole site of recurrence after curative resection of gastric cancer, focusing on the results achieved by different therapies and to investigate the prognostic factors of major clinical relevance. METHODS: Retrospective multi-center chart review evaluating 73 patients, previously submitted to D>/=2 gastrectomy for gastric cancer, who developed exclusive hepatic recurrence. Prognostic factors related to the patient, to the gastric malignancy and its treatment, and to the metastatic disease and its therapy were evaluated. RESULTS: Forty-five patients received supportive care, 17 were submitted to chemotherapy, and 11 to hepatic resection. Survival was independently influenced by the variables T (p=0.019), N (p=0.05) and G (p=0.018) of the gastric primary and by the therapeutic approach to the metastases (p<0.005). In particular, T4 gastric cancer, presence of lymph-node metastases and G3 tumor displayed a negative prognostic value. Therapeutic approach to the metastases was the principal prognostic variable: 1, 2, and 3 years survival rates were 22.2%, 4.4% and 2.2%, respectively, for patients without specific treatment; 44.9%, 12.8% and 6.4% after chemotherapy (p=0.08) and 80.8%, 30.3% and 20.2% after surgical resection (p<0.001). CONCLUSIONS: Our data suggest some clinical criteria that may facilitate selection of therapy for patients with hepatic recurrence after primary gastric cancer resection. The best survival rates are associated with surgical treatment, which should be chosen whenever possible.

The aminoxyl radical BTNO (benzotriazole-N-oxyl;>N-O ) is generated from HBT (1-hydroxybenzotriazole;>N-OH) by oxidation with a Ce(IV) salt. BTNO presents a broad absorption band with lambda(max) 474 nm that lends itself to investigate the kinetics of H-abstraction from H-donor substrates by spectrophotometry. Thus, rate constants (k(H)) of H-abstraction by BTNO from CH(2)-groups alpha to the nitrogen atom in X-substituted-(N-acetyl)benzylamines (X-C(6)H(4)CH(2)NHCOCH(3)) have been determined in MeCN solution at 25 degrees C. Correlation of the k(H)(X) data with the Hammett sigma(+) parameters gives a small value for rho (-0.65) that is compatible with a radical H-abstraction step. The sizeable value (k(H)/k(D)= 8.8) of the kinetic isotope effect from a suitably deuteriated amide substrate further confirms H-abstraction as rate-determining. Evidence is acquired for the relevance of stereoelectronic effects that speed up the H-abstraction whenever the scissile C-H bond is co-linear with either the nitrogen lone-pair of the amide moiety or an adjacent aromatic group. An assessment of the dissociation energy value of the benzylic C-H bond in ArCH(2)NHCOMe is accordingly reported.

We present a systematic study of dynamical heterogeneity in a model for permanent gels upon approaching the gelation threshold. We find that the fluctuations of the self-intermediate scattering function are increasing functions of time, reaching a plateau whose value, at large length scales, coincides with the mean cluster size and diverges at the percolation threshold. Another measure of dynamical heterogeneities-i.e., the fluctuations of the self-overlap-displays instead a peak and decays to zero at long times. The peak, however, also scales as the mean cluster size. Arguments are given for this difference in the long-time behavior. We also find that the non-Gaussian parameter reaches a plateau in the long-time limit. The value of the plateau of the non-Gaussian parameter, which is connected to the fluctuations of diffusivity of clusters, increases with the volume fraction and remains finite at the percolation threshold.

We measure the number Omega(varphi) of mechanically stable states of volume fraction varphi of a granular assembly under gravity. The granular entropy S(varphi)=logOmega(varphi) vanishes both at high density, at varphi approximately varphi_{rcp}, and a low density, at varphi approximately varphi_{rvlp}, where varphi_{rvlp} is a new lower bound we call random very loose pack. varphi_{rlp} is the volume fraction where the entropy is maximal. These findings allow for a clear explanation of compaction experiments and provide the first first-principle definition of the random loose volume fraction. In the context of the statistical mechanics approach to static granular materials, states with varphi<varphi_{rlp} are characterized by a negative temperature.

BACKGROUND/AIMS: Post discharge prescriptions and follow-up protocols after non-operative treatment of blunt liver injuries are still controversial. The aim of this study was to detail the evolution of the hepatic injuries considering their different patterns and severity grades, stated by the Liver Injury Scale. METHODOLOGY: Analysis of a database concerning 79 consecutive patients submitted to ultrasound follow-up until complete recovery of liver injury. RESULTS: All patients had an uncomplicated course and the liver restoration was demonstrated between 3 and 300 days after the trauma. The median healing time of hematomas increased with the grading (p<0.001): 6 days (IQR=6.75), 45.5 days (IQR=91) and 108 days (IQR=89) for I, II and III grade lesions, respectively. Similarly behaved the lacerations and 29 days (IQR=14.25), 34 days (IQR=43.5) and 77.5 days (IQR=83.5) was the median healing time of II, III and IV grade lesions, statistical significance emerging only comparing II to IV grade lacerations (p<0.035). Considering the different lesion patterns within the same severity grade, the liver restoration was more prompt after lacerations (p<0.001). CONCLUSIONS: These data suggest that medical prescriptions and follow-up protocols can be tailored considering the lesion characteristics.