Magnetic-field effects in defect-controlled ferromagnetic Ga_{1-x}Mn_xAs semiconductors

We have studied the magnetic-field and concentration dependences of the magnetizations of the hole and Mn subsystems in diluted ferromagnetic semiconductor Ga_{1-x}Mn_xAs. A mean-field approximation to the hole-mediated interaction is used, in which the hole concentration p(x) is parametrized in terms of a fitting (of the hole effective mass and hole/local moment coupling) to experimental data on the Tc critical temperature. The dependence of the magnetizations with x, for a given temperature, presents a sharply peaked structure, with maxima increasing with applied magnetic field, which indicates that application to diluted-magnetic-semiconductor devices would require quality-control of the Mn-doping composition. We also compare various experimental data for Tc(x) and p(x) on different Ga_{1-x}Mn_xAs samples and stress the need of further detailed experimental work to assure that the experimental measurements are reproducible.Comment: RevTeX 4, 3 two-column pages, 4 colour figures; to appear in J Appl Phy

Anterior Hepatic Transection for Caudate Lobectomy

Resection of the caudate lobe (segment I- dorsal sector, segment IX- right paracaval region, or both) is often technically difficult due to the lobe’s location deep in the hepatic parenchyma and because it is adjacent to the major hepatic vessels (e.g., the left and middle hepatic veins)

Adherence to BCLC recommendations for the treatment of hepatocellular carcinoma: impact on survival according to stage

OBJECTIVES: This study sought to assess the adherence of newly diagnosed hepatocellular carcinoma patients to the Barcelona Clinic Liver Cancer system treatment guidelines and to examine the impact of adherence on the survival of patients in different stages of the disease. METHODS: This study included all patients referred for the treatment of hepatocellular carcinoma between 2010 and 2012. Patients (n=364) were classified according to the Barcelona Clinic Liver Cancer guidelines. Deviations from the recommended guidelines were discussed, and treatment was determined by a multidisciplinary team. The overall survival curves were estimated with the Kaplan-Meier method and were compared using the log-rank test. RESULTS: The overall rate of adherence to the guidelines was 52%. The rate of adherence of patients in each scoring group varied as follows: stage 0, 33%; stage A, 45%; stage B, 78%; stage C, 35%; and stage D, 67%. In stage 0/A, adherent patients had a significantly better overall survival than non-adherent patients (hazard ratio=0.19, 95% confidence interval (CI): 0.09-0.42;

Liver biopsy may facilitate pancreatic graft evaluation: Positive association between liver steatosis and pancreatic graft adipose infiltration

OBJECTIVES: The number of pancreatic transplants has decreased in recent years. Pancreatic grafts have been underutilized compared to other solid grafts. One cause of discard is the macroscopic appearance of the pancreas, especially the presence of fatty infiltration. The current research is aimed at understanding any graft-related association between fatty tissue infiltration of the pancreas and liver steatosis. METHODS: From August 2013 to August 2014, a prospective cross-sectional clinical study using data from 54 multiple deceased donor organs was performed. RESULTS: Micro- and macroscopic liver steatosis were significantly correlated with the donor body mass index ([BMI]; p=0.029 and p=0.006, respectively). Positive gamma associations between pancreatic and liver macroscopic and microscopic findings (0.98; confidence interval [CI]: 0.95-1 and 0.52; CI 0.04-1, respectively) were observed. Furthermore, comparisons of liver microscopy findings showed significant differences between severe versus absent (

A mathematical model for optimizing the indications of liver transplantation in patients with hepatocellular carcinoma

Abstract Background The criteria for organ sharing has developed a system that prioritizes liver transplantation (LT) for patients with hepatocellular carcinoma (HCC) who have the highest risk of wait-list mortality. In some countries this model allows patients only within the Milan Criteria (MC, defined by the presence of a single nodule up to 5 cm, up to three nodules none larger than 3 cm, with no evidence of extrahepatic spread or macrovascular invasion) to be evaluated for liver transplantation. This police implies that some patients with HCC slightly more advanced than those allowed by the current strict selection criteria will be excluded, even though LT for these patients might be associated with acceptable long-term outcomes. Methods We propose a mathematical approach to study the consequences of relaxing the MC for patients with HCC that do not comply with the current rules for inclusion in the transplantation candidate list. We consider overall 5-years survival rates compatible with the ones reported in the literature. We calculate the best strategy that would minimize the total mortality of the affected population, that is, the total number of people in both groups of HCC patients that die after 5 years of the implementation of the strategy, either by post-transplantation death or by death due to the basic HCC. We illustrate the above analysis with a simulation of a theoretical population of 1,500 HCC patients with tumor size exponentially. The parameter λ obtained from the literature was equal to 0.3. As the total number of patients in these real samples was 327 patients, this implied in an average size of 3.3 cm and a 95% confidence interval of [2.9; 3.7]. The total number of available livers to be grafted was assumed to be 500. Results With 1500 patients in the waiting list and 500 grafts available we simulated the total number of deaths in both transplanted and non-transplanted HCC patients after 5 years as a function of the tumor size of transplanted patients. The total number of deaths drops down monotonically with tumor size, reaching a minimum at size equals to 7 cm, increasing from thereafter. With tumor size equals to 10 cm the total mortality is equal to the 5 cm threshold of the Milan criteria. Conclusion We concluded that it is possible to include patients with tumor size up to 10 cm without increasing the total mortality of this population

Adherence to BCLC recommendations for the treatment of hepatocellular carcinoma: impact on survival according to stage

OBJECTIVES: This study sought to assess the adherence of newly diagnosed hepatocellular carcinoma patients to the Barcelona Clinic Liver Cancer system treatment guidelines and to examine the impact of adherence on the survival of patients in different stages of the disease. METHODS: This study included all patients referred for the treatment of hepatocellular carcinoma between 2010 and 2012. Patients (n=364) were classified according to the Barcelona Clinic Liver Cancer guidelines. Deviations from the recommended guidelines were discussed, and treatment was determined by a multidisciplinary team. The overall survival curves were estimated with the Kaplan-Meier method and were compared using the log-rank test. RESULTS: The overall rate of adherence to the guidelines was 52%. The rate of adherence of patients in each scoring group varied as follows: stage 0, 33%; stage A, 45%; stage B, 78%; stage C, 35%; and stage D, 67%. In stage 0/A, adherent patients had a significantly better overall survival than non-adherent patients (hazard ratio=0.19, 95% confidence interval (CI): 0.09-0.42; p<0.001). Among the stage D patients, the overall survival rate was worse in adherent patients than in non-adherent patients (hazard ratio=4.0, 95% CI: 1.67-9.88; p<0.001), whereas no differences were observed in patients in stages B or C. CONCLUSIONS: The rate of adherence to the Barcelona Clinic Liver Cancer staging system in clinical practice varies according to clinical disease stage. Adherence to the recommended guidelines positively impacts survival, especially in patients with early-stage disease

Does bilioenteric anastomosis impair results of liver resection in primary intrahepatic lithiasis?

AIM: To evaluate the long-term results of liver resection for the treatment of primary intrahepatic lithiasis. Prognostic factors, especially the impact of bilioenteric anastomosis on recurrence of symptoms were assessed