Exchange bias driven by Dzyaloshinskii-Moriya interactions.

The exchange bias effect in a compensated IrMn3/Co(111) system is studied using multiscale modeling from ab initio to atomistic spin model calculations. We evaluate numerically the out-of-plane hysteresis loops of the bilayer for different thicknesses of the ferromagnetic layer. The results show the existence of a perpendicular exchange bias and an enhancement of the coercivity of the system. To identify the origin of the exchange bias, we analyze the hysteresis loops of a selected bilayer by tuning the different contributions to the exchange interaction across the interface. Our results indicate that the exchange bias is primarily induced by Dzyaloshinskii-Moriya interactions, while the coercivity is increased mainly due to a spin-flop mechanism.

Pieloplastia sin drenaje intrarrenal en pacientes pediátricos / Pyeloplasty Without Intrarenal Stent in Pediatric Patients

Objetivos: A pesar del avance de cirugías mínimamente invasivas, la pieloplastia desmembrada a cielo abierto sigue siendo una cirugía muy utilizada en Pediatría, especialmente en niños pequeños. El propósito de este trabajo es presentar nuestra experiencia en la realización de esta técnica a través de una mínima incisión y sin dejar catéteres intrarrenales transanastomóticos. Materiales y métodos: Revisión retrospectiva desde julio de 1992 a julio de 2009, tiempo en el que 348 pacientes fueron operados de pieloplastia desmembrada a cielo abierto. Un total de310 pacientes (89%), 223 niños y 87 niñas, fueron intervenidos sin dejar catéter intrarrenal. La incisión fue de 2 a 2,5 cm en flanco. En todos los pacientes se dejó drenaje perirrenal y sonda vesical, esta última las primeras 24 h. Resultados: En total se realizaron 319 pieloplastias sin catéteres intrarrenales, 174 (54,5%) del lado izquierdo, 127 (39,8%) del lado derecho y 9 (5,6%) bilaterales. El intervalo de edad fue de14 días a 18 años, siendo el 58% de los niños menor de 12 meses. Con un seguimiento medio de 6,7 años (17 años a 11 meses), 312 pieloplastias (97,8%) fueron realizadas con éxito, con persistencia del patrón obstructivo en 7 pacientes que precisaron una nueva pieloplastia a cielo abierto (2,2%). Otras complicaciones fueron: drenaje prolongado (6), infección de herida (1) y fiebre/infección urinaria (2). La estancia media fue de 22 h. Conclusiones: La pieloplastia desmembrada a cielo abierto es altamente efectiva en el tratamiento de la estenosis pieloureteral en niños, y prescindir de los catéteres intrarrenales no perjudica su éxito (AU)

Purpose: In spite of advances in minimally invasive endoscopic surgery, open dismembered pyeloplasty continues to be used in many pediatric centers, especially in small children. The purpose of this work is to present our experience in the performance of this technique using a minimally invasive open pyeloplasty without intrarenal stents. Material and methods: A retrospective review was made of patients between July 1992 and July 2009. During this time, 348 patients underwent open dismembered pyeloplasty. A total of 310 patients (89%), 223 boys and 87 girls, underwent open pyeloplasty without intrarenal stent. The incision was from 2 to 2.5 cm in the flank. An extrarenal drain (3-5 days) and a bladder catheter (< 24 hs) were placed in all patients. Results: A total of 319 pyeloplasties were performed without intrarenal catheter in our Service. Of these, 174 (54.5%) were on the left side, 127 (39.8%) on the right side and 9 (5.6%) were bilateral. Age interval was 14 days to 18 years, 58% of the children being younger than 12months at the time of surgery. With a mean follow-up of 6.7 years (17 years to 11 months), 312pyeloplasties (97.8%) were successful, with persistence of the obstructive patient in 7 patients who required a new open pyeloplasty (2.2%). Other complications were: prolonged drainage (6), wound infection (1), and urinary infection (2). Mean stay was 22 hours. Conclusions: Open dismembered pyeloplasty is a safe and effective treatment choice for pyeloureteral stenosis in children and can be done without intrarenal stents with no detriment to its success (AU)

[Pyeloplasty without intrarenal stent in pediatric patients]. / Pieloplastia sin drenaje intrarrenal en pacientes pediátricos.

PURPOSE: In spite of advances in minimally invasive endoscopic surgery, open dismembered pyeloplasty continues to be used in many pediatric centers, especially in small children. The purpose of this work is to present our experience in the performance of this technique using a minimally invasive open pyeloplasty without intrarenal stents. MATERIAL AND METHODS: A retrospective review was made of patients between July 1992 and July 2009. During this time, 348 patients underwent open dismembered pyeloplasty. A total of 310 patients (89%), 223 boys and 87 girls, underwent open pyeloplasty without intrarenal stent. The incision was from 2 to 2.5 cm in the flank. An extrarenal drain (3-5 days) and a bladder catheter (< 24 hs) were placed in all patients. RESULTS: A total of 319 pyeloplasties were performed without intrarenal catheter in our Service. Of these, 174 (54.5%) were on the left side, 127 (39.8%) on the right side and 9 (5.6%) were bilateral. Age interval was 14 days to 18 years, 58% of the children being younger than 12 months at the time of surgery. With a mean follow-up of 6.7 years (17 years to 11 months), 312 pyeloplasties (97.8%) were successful, with persistence of the obstructive patient in 7 patients who required a new open pyeloplasty (2.2%). Other complications were: prolonged drainage (6), wound infection (1), and urinary infection (2). Mean stay was 22 hours. CONCLUSIONS: Open dismembered pyeloplasty is a safe and effective treatment choice for pyeloureteral stenosis in children and can be done without intrarenal stents with no detriment to its success.

Liver transplantation results for hepatocellular carcinoma in Chile.

UNLABELLED: Hepatocellular carcinoma (HCC) is the most common malignant tumor of the liver. Liver transplantation is the best treatment for HCC; it improves survival, cures cirrhosis, and abolishes local recurrence. We describe the outcomes of patients with HCC who underwent liver transplantation in two liver transplantation centers in Chile. METHODS: This study is a clinical series elaborated from the liver transplantation database of Pontificia Universidad Católica and Clínica Alemana between 1993 and 2009. The survival of patients was calculated using the Kaplan-Meier survival analysis. The significant alpha level was defined as <.05. RESULTS: From 250 liver transplantations performed in this period, 29 were due to HCC. At the end of the study, 25 patients (86%) were alive. The mean recurrence-free survival was 30 months (range 5 months to 8 years). The 5-year survival for patients transplanted for HCC was >80%; however, the 5-year overall survival of patients who exceeded the Milan criteria in the explants was 66%. There was no difference in overall survival between patients transplanted for HCC versus other diagnosis (P = .548). CONCLUSION: This series confirmed that liver transplantation is a good treatment for patients with HCC within the Milan criteria.

Bridge therapy in hepatocellular carcinoma before liver transplantation: the experience of two Chilean centers.

BACKGROUND: Orthotopic liver transplantation (OLT) is currently an established therapy for small, early-stage hepatocellular carcinoma (HCC) within the Milan criteria. Long waiting times due to the shortage of donor organs can result in tumor progression and drop-out from OLT candidacy. Therefore a wide variety of procedures are necessary before OLT. The aim of this retrospective study was to review our experience in relation to bridge therapy prior to OLT for HCC. METHODS: This was a retrospective database review of all of the patient who underwent transplantation in our institutions between January 1993 and June 2009. We analyzed patients with a diagnosis of HCC in the explant. RESULTS: Among 29 patients, including 12 who were diagnosed by the explant and 17 prior to transplantation, 88% underwent bridge therapy during a mean waiting time to OLT of 12 months. Among the 23 procedures, namely 1.5 procedures per patient, included most frequently chemoembolization (48%), alcohol ablation (30%), radiofrequency ablation (13%), and surgery (9%). Thirty-three percent of the explants contained lesions within the Milan criteria. In our series the 5-year survival rate for patients transplanted for HCC was 86%; in the bridge therapy group, it was 73%. CONCLUSIONS: The incidence of patients who underwent bridge therapy (52%) was similar to other reported experiences, but the fulfillment of Milan criteria in the explants was lower. Among the bridge therapy group, the survival was slightly lower, probably because this group displayed more advanced disease.

Field induced vortex dynamics in magnetic Ni nanotriangles.

The magnetization states in Ni triangular dots under an applied magnetic field have been studied using variable-field magnetic force microscopy (VF-MFM) imaging. In order to understand their dynamics we performed micromagnetic simulations which are in remarkable agreement with the experimental MFM results. The nanostructures present magnetic vortices as ground states which move under an external magnetic field. The combination of micromagnetic simulations and MFM imaging allows us to identify correctly the vortex chiralities and polarizations. The triangular geometry produces an improved contrast of the vortex core. Additionally, the vortices of different chiralities present clearly different MFM images under an applied field.

Estudio clínico de eficacia y tolerancia con sultamicilina fipexiam en procesos infecciosos de tratamiento ambulatorio / Clinic study of efficacy and toleration with sultamicilina fipeham in infectious process of ambulatory treatment

Se realizó un estudio abierto, multicéntrico, no comparativo donde se avaluó la eficacia y tolerancia de la combinación Ampicilina/Sulbatam por vía oral-Sultamicilina-(Fipexiam), en adultos y niños con infecciones del tracto respiratorio superior e inferior y con infeciones de piel y partes blandas, y adultos con Enfermedad Inflamatoria Pélvica (EIP). El estudio reunió los investigadores de 73 Centros. Se trataron un total de 195 pacientes obteniéndose una efectividad global de 93.3 por ciento. De estos pacientes 84 presentaron Otitis media aguda, resultando curas clínicas en el 89.2 por ciento, 67 presentaron procesos orofaríngeos con curación en el 94 por ciento; en los casos con infecciones de piel y partes blandas, así como en las mujeres tratadas con (EIP) la curación clínica fue de 100 por ciento. Se reportaron efectos adversos en 10.9 por ciento, siendo las molestias gastrointestinales más resaltantes con 8.7 por ciento de los casos reportados, siendo menores a lo reportado por la literatura médica

[Mother's work and severity of accidental injuries in children]. / El trabajo materno y la gravedad de lesiones accidentales en niños.

A study was conducted in children under five years old, in order to establish the association between the mother's work and the severity of unintentional injuries. The study was carried out at the emergency room of six pediatric hospitals in Mexico City. Cases were children with major injuries that required hospitalization, intensive care, surgery, or who died as a result of the injury. Controls were children of similar age, with minor injuries resolved at the emergency room. Sample size was 350 cases and 350 controls. Variables were grouped according to: mother's occupation; characteristics of the child, socioeconomic status, child care, and those related with home risk factors. Results showed a protective effect on severity of injuries when the mother worked outside home in comparison to mothers who do not work, (or 0.79, 95%CI 0.57-1.07). No differences were found with respect to sex and age of children. Mother age under 24 years old and low schooling (< 3 years of elementary school) were statistically significant with a risk of major injuries (or 2.30, 95%CI 1.5-3.4). Delay of demand of medical care after 60 minutes of injury occurrence is related with a risk of major injury (or 1.68, 95% CI 1.2-2.3). No differences related with household risk factors were found. Results provide valuable information about risk factors related with injury severity and the association with mother's work.