ABSTRACT Compaction is a recurring problem in soils of the dryland zone of the Araucanía Region, affecting yields considerably. The objective of this study was to determine the persistence over time of the effect of subsoiling, as a tool to reduce soil compaction, on a soil under crop rotation-grazing. A field experiment was established for 5 consecutive seasons (t). Soil compaction was measured at a depth of 0-45 cm, using the Cone Index as an indicator and considering ≥2000 kPa as compacted soil. The diagnosis was conducted in 2015 (t0), while the experimental trials started in 2016 (t1) when oats were sown on a site with two different treatments: ‘Subsoiling’ and ‘No subsoiling’. The obtained results showed that subsoiling increased yield by 14.9% compared to the no subsoiling treatment. Subsequently, the experimental site was used for grazing without animal load control from 2017 to 2020 (t1-t5). During this period, the persistence of the effect of subsoiling on the experimental site was evaluated by measuring soil compaction of a depth of 0-45 cm and contrasting the values to those obtained in 2015 (t0). In the last season (t5), the 0-10 cm profile showed surface compaction, which was attributed to grazing. It can be concluded that compaction levels (kPa) return to the original levels (t0) from the second season after subsoiling (t2), which ends the residual effect derived from the use of this tool.

RESUMEN La compactación es un problema que se presenta de manera recurrente en los suelos del secano interior de la Región de La Araucanía, afectando considerablemente los rendimientos. El objetivo de este estudio fue determinar la persistencia en el tiempo del efecto del subsolado, como herramienta utilizada para descompactar, en un suelo bajo rotación de cultivos-pastoreo. Se estableció un ensayo de seguimiento por 5 temporadas consecutivas (t), midiendo la compactación dentro del perfil de 0-45 cm de profundidad, considerando lecturas del Índice de Cono ≥2000 kPa como indicador de suelo compactado. El diagnóstico se realizó el año 2015 (t0), mientras que los ensayos de seguimiento se iniciaron el 2016 (t1) con una siembra de avena, incluyendo dos tratamientos: “Con subsolado” y “Sin subsolado”. Los resultados obtenidos indican que la utilización del subsolado incrementó el rendimiento un 14,9% comparado con el testigo (sin subsolado). Posteriormente, el sitio experimental fue utilizado para pastoreo extensivo todo el año sin regulación de carga animal entre las temporadas 2017-2020 (t2-t5). Durante ese periodo, se realizó el seguimiento de la persistencia del efecto del subsolado en el espacio ocupado por las parcelas experimentales, evaluando la compactación del perfil de 0-45 cm y contrastando los valores obtenidos el 2015 (t0). En la última temporada evaluada (t5), el perfil de 0-10 cm presentó lecturas superiores al límite considerado como compactado, lo cual fue atribuido al uso ganadero del sitio. Se concluye que las lecturas del grado de compactación (kPa) retornan a la condición original (t0) a partir de la segunda temporada luego del subsolado (t2), con lo cual se termina el efecto residual del subsolado.

OBJETIVO: Avaliar os resultados de resultados da aplicação de um protocolo terapêutico de natureza prospectiva, com seguimento em longo prazo nos termos de taxas de sobrevivência em uma coorte de pacientes operados com carcinoma vesícula biliar (CVB) intermédio e avançado. MÉTODOS: A coorte prospectiva de pacientes com estágios intermediários e avançados de CVB tratados entre 1996 e 2006. Todos os casos foram tratados com uma segmentectomia hepática parcial em segmentos IVb e V e uma dissecção linfonodal regional e seis ciclos de quimioterapia de ambulatório (5-FU e leukovorin). Com um tempo de seguimento médio de 31,5 meses, a morbidade, mortalidade operatória, hepático e infiltração linfática e atuarial de sobrevida foram medidas. Estatísticas descritivas foram aplicadas, bem como análise bivariada aplicando o teste exato de Fisher, testes não-paramétricos, curvas de sobrevida Kaplan Meier e técnica de regressão logística e risco proporcional de Cox. RESULTADOS: Foram incluídos 40 pacientes neste protocolo, com uma média de idade de 59,5 anos (40-85 anos), dos quais 28 eram mulheres (70%). Profundidade de infiltração parede: muscular 8 pacientes (20%), subserosal 12 pacientes (30%), serosas 12 pacientes (30%) e perivesicular no tecido adiposo, 8 pacientes (20%). A série morbidade foi de 27,5%. Não houve mortalidade operatória. A quimioterapia foi bem tolerada. A sobrevida global atuarial da série foi de 50% em 60 meses. CONCLUSÃO: Nosso protocolo tem tratamento morbidade, mortalidade e taxas de sobrevivência semelhantes às relatadas anteriormente série.

PURPOSE: To evaluate the results of a prospective therapeutic protocol with long-term follow up in terms of survival rates in a cohort of patients treated with Intermediate and Advanced GBC (GBC). METHODS: Prospective cohort of patients with intermediate and advanced stages of GBC treated between 1996 and 2006. All cases were treated with a partial hepatic segmentectomy on segments IVb and V and a regional lymph node dissection and six cycles of out-patient chemotherapy (5-FU and leukovorin). With an average follow-up of 31.5 months, the morbidity, operative mortality, hepatic and lymphatic infiltration and actuarial survival were measured. Descriptive statistics were applied as well as bivariate analysis applying Fisher's exact test and non-parametrical tests and Kaplan Meier survival curves. Also logistic regression and proportional risk of Cox were applied. RESULTS: 40 patients were included in this protocol, with an average age of 59.5 years (40-85 years), of which 28 were women (70%). Depth of wall infiltration: muscular 8 patients (20%), subserosal 12 patients (30%), serosal 12 patients (30%) and perivesicular adipose tissue 8 patients (20%). The series morbidity was 27.5%. There was no operative mortality. The chemotherapy was well tolerated. The overall actuarial survival in the series was 50% at 60 months. CONCLUSION: Our protocol treatment has morbidity, mortality and survival rates similar to previously reported series.

In certain situations, which occur with particular frequency in the field of surgery and its related disciplines (where what predominates are observational-type studies), the management of randomized controlled clinical trials (RCT) is very difficult and as such, conducting a systematic review (SR) based on RCT and realice a meta-analysis is even more difficult. Therefore, we have generated a methodology for implementing a SR with different types of designs (including observational studies) as an alternative in order to clarify the uncertainty in the field of therapy when there are few RCT and the evidence relies so heavily on descriptive and observational studies. The aim of this study, was to set out a methodology that leads to a SR with various types of designs. Methodologycally, this is based on consideration of the different primary studies through the application of a methodological quality score made up of 3 items (type of study design, size of the population studied and methodology used in the study). Once assigned a point score, a calculation of weighted averages with their respective confidence intervals of 95% is applied to each variable to be studied, which finally enables to apply a meta-analysis and compare groups. A methodological proposal leading to a SR with various types of designs.

En ciertas situaciones, en especial frecuentes en el ámbito de la cirugía y sus disciplinas afines (donde lo que predomina son estudios de tipo observacional), la conducción de ensayos clínicos con asignación aleatoria (EC) es muy difícil; por ende, realizar revisiones sistemáticas (RS) con base en EC y posteriormente meta-analizar la información lo es aún más. Por esta razón hemos generado una metodología para realizar RS con diferentes tipos de diseños (incluyendo estudios observacionales), como una alternativa para aclarar la incertidumbre en el ámbito de la terapia cuando existen pocos EC y la evidencia se apoya fundamentalmente en estudios descriptivos y observacionales. El objetivo de este estudio fue exponer una metodología para conducir RS con diversos tipos de diseños. La metodología, se basa en la ponderación de los diferentes estudios primarios a través de la aplicación de un escore de calidad metodológica compuesto por 3 ítems (tipo de diseño del estudio, tamaño de la población estudiada y metodología empleada en el estudio). Una vez asignado un puntaje se aplica un cálculo de promedios ponderados con sus respectivos intervalos de confianza del 95% a cada variable que se desee estudiar, lo que permite finalmente realizar un meta-análisis y comparar grupos. Se presenta una propuesta metodológica para conducir RS con diversos tipos de diseños.

Background: Antimicrobial prophylaxis is a common practice in surgery. However its indication in elective laparoscopic cholecystectomy is controversial. Aim: To determine the effectiveness of antimicrobial prophylaxis in elective laparoscopic cholecystectomy. Material and methods: Systematic literature review of clinical trials and cohort studies in subjects over 18 years of age, comparing the effect antimicrobial prophylaxis versus placebo in the incidence of operative site infections. Cochrane, MEDLINE, Scielo and LiLACS databases were consulted. The methodological quality of studies was assessed using the MINCIR store, that ranges from 6 to 36. Results: Nine clinical trials and two cohort studies were analyzed. The mean MINCIR score of the studies was 18.5. The total population of all studies were 2271 patients (1196 receiving antimicrobial prophylaxis and 1077 receiving placebo). Both groups were comparable in age, weight, surgical time and length of hospital stay. The meta analysis gave a final odds ratio for the risk of infection of 0.73 (95% confidence interval 0.43-1.23). Sensitivity analysis, excluding cohort studies gave an odds ratio of 0.95 (95% confidence interval 0.48-1.9). Thus, in both situations no protective effect of antimicrobial prophylaxis on operative site infections was demonstrated. Conclusions: This systematic review does not support the use antimicrobial prophylaxis in elective laparoscopic cholecystectomy

Introducción: El uso de la profilaxis antibiótica (PA) es una práctica común en cirugía, sin embargo, su indicación en la colecistectomía laparoscópica electiva (CLE) es controversial. El objetivo de este estudio es determinar la efectividad de la PA en CLE en relación a incidencia de infección del sitio operatorio (ISO). Material y método: Se realizó una revisión sistemática de la literatura (RS), analizando ensayos clínicos aleatorios (ECA) y estudios de cohortes (EC), cuya población fueran sujetos mayores de 18 años sometidos a CLE en quienes se comparara el uso de un esquema de PA vs. placebo. Se consultaron las bases de datos Cochrane, MEDLINE, SciELO y LiLACS, a través de términos MeSH, palabras libres y términos booleanos. La calidad metodológica de los estudios fue valorada mediante la aplicación del escore MINCIR cuya puntuación fluctúa entre 6 y 36 puntos. Se aplicó estadística descriptiva, meta-análisis para la comparación de grupos y análisis de sensibilidad. Resultados: Se analizaron 10 artículos que generaron 11 estudios comparativos (9 ECA y 2 EC). La mediana de la calidad metodológica de los estudios analizados fue de 18,5 puntos. La población de los estudios es de 2271 pacientes (1196 con PAy 1077 con placebo). No se verificaron diferencias estadísticamente significativas en las variables edad, peso, tiempo quirúrgico ni estancia hospitalaria en los grupos en estudio. El meta-análisis dio un odds ratio final de 0,726 (IC de 95% de 0,429 -1,226); y el análisis de sensibilidad excluyendo los EC, un OR de 0,954 (IC de 95% de 0,480 - 1,897); es decir que, en ambas situaciones, no se estableció un efecto protector del uso de PA sobre el desarrollo de ISO en pacientes sometidos a CLE. Conclusión: La evidencia encontrada en esta RS no sustenta el uso de PA en CLE

There are doubts about the effectiveness of laparoscopic treatment of hepatic tumors and cysts. Aim: To assess the available evidence about the effectiveness of laparoscopic treatment of hepatic tumors and cysts and liver resections. Material and methods: A search in MEDLINE, EMBASE and Cochrane library databases was done, considering all studies published between 1988 and 2006. The internal validity of the evidence and global quality of the reports was assessed. Results: Thirty seven reports were included (two systematic revisions, six cohort studies and 29 case series). The quality of evidence about the effectiveness of laparoscopic treatment of hepatic cysts, when compared with the open approach, is low. Resective and non resective options are available for the laparoscopic treatment of hepatic tumors. There are no studies available comparing the effectiveness and safety of these two approaches. Laparoscopic hepatic resections have less blood loss and require a shorter hospital stay than the open approach. The available evidence on complications and mortality is scarce and of low quality. There are no studies available about the effectiveness and safety of laparoscopic hepatic resections. Conclusions: Since the evidence is scanty and low quality, no recommendations can be made about laparoscopic treatment of hepatic cysts or tumors and liver resections

Introducción: Existe controversia acerca de la eficacia, efectividad y eficiencia del tratamiento laparoscópico de quistes y tumores hepáticos, así como respecto de las resecciones hepáticas por vía laparoscópica. El objetivo de este estudio es evaluar la evidencia disponible sobre la efectividad de la cirugía laparoscópica en el tratamiento de quistes (QH) y tumores hepáticos, (TH) así como respecto de las resecciones hepáticas por vía laparoscópica (RHVL). Métodos: Se realizó una búsqueda en las bases de datos MEDLINE, EMBASE y la biblioteca Cochrane. Se consideraron todo tipo de estudios publicados entre 1988 y 2006 y se llevó a cabo la evaluación de la validez interna de la evidencia así como de su calidad global. Resultados: Se incluyeron 37 estudios (2 revisiones sistemáticas, 6 estudios de cohortes y 29 series de casos). Existen diferentes opciones para el tratamiento laparoscópico de los QH; sin embargo, la calidad de la evidencia sobre la eficacia del tratamiento laparoscópico de éstos, respecto de la vía abierta, es baja. Existen diferentes opciones de tratamiento laparoscópico para los TH, entre las que destacan el tratamiento resectivo y las terapias no resectivas. No se dispone de estudios comparativos respecto a la eficacia y seguridad del tratamiento laparoscópico resectivo o no resectivo en TH. Existe evidencia que las RHVL se asocian con menor estancia hospitalaria y reducción de las pérdidas hemáticas respecto de las resecciones vía abierta. La evidencia disponible sobre morbilidad y mortalidad de RHVL es escasa y de calidad baja. No se dispone de estudios comparativos sobre eficacia y seguridad de las RHVL. Conclusiones: La evidencia disponible es escasa y de baja calidad metodológica, situación que dificulta la formulación de recomendaciones. Son necesarios estudios de mejor calidad que evalúen de manera adecuada éstas técnicas

Introduction: Laparoscopy is the gold standard treatment for cholecystolithiasis. However its efficacy is not yet entirely known. The aim of this study is to evaluate the available evidence on the effectiveness of laparoscopic surgery for treating cholecystolithiasis and common bile duct lithiasis (CBDL). Material and Method: MEDLINE, EMBASE and The Cochrane Library databases were searched. All studies published between 1998 and 2006 were considered. Internal validity and global quality were assessed. Results: 80 studies were selected (9 systematic reviews, 19 clinical trials, 4 clinical practice guidelines, 15 cohort studies, 1 case and control studies and 32 case series). When compared with cholecystectomy, laparoscopic cholecystectomy (LC) is associated with less operating time, a shorter hospital stay and better quality of life, as it is a relatively safe procedure (high quality). Use of antibiotic prophylaxis results in no benefit in reducing infection rate in low-risk patients (hight quality). Despite the number of technological variants for performing a LC, their effectiveness is low and inconclusive. For treating CBDL, two-stage surgery is the most appropiate strategy for high-risk patients (high quality). Mortality is similar to open surgery as is effectiveness to endoscopio treatment (high quality). Conclusion: Recommendations are difficult given the lack of available evidence and the low methodological quality. Better quality studies assessing these techniques more adequately are warranted

Introducción: La laparoscopia es el estándar de referencia en el tratamiento de la colecistolitiasis. No obstante su efectividad es todavía poco conocida. El objetivo de este estudio es evaluar la evidencia disponible sobre la efectividad de la cirugía laparoscópica en el tratamiento de la colecistolitiasis y de la litiasis de la vía principal (LVBP). Material y Métodos: Se realizó una búsqueda en las bases de datos MEDLINE, EMBASE y la biblioteca Cochrane. Se consideraron todo tipo de estudios publicados entre 1988 y 2006. Se llevó a cabo la evaluación de la validez interna de la evidencia así como su calidad global. Resultados: Se seleccionaron 80 estudios (9 revisiones sistemáticas, 19 ensayos clínicos, 4 guías de práctica clínica, 15 estudios de cohortes, 1 de casos y controles y 32 series de casos). La colecistectomía laparoscópica (CL), respecto de la colecistectomía, se asocia a mayor tiempo operatorio, menor estancia hospitalaria y mejor calidad de vida, siendo un procedimiento relativamente seguro (calidad alta). El uso de profilaxis antibiótica no ofrece ningún beneficio en términos de disminución de la tasa de infecciones en pacientes de bajo riesgo [calidad alta]. Se han descrito multiplicidad de variantes tecnológicas para la realización de una CL, no obstante, la efectividad de las mismas es escasa y no concluyente. En el tratamiento de la LVBP, la cirugía en dos etapas es la estrategia más apropiada en pacientes de alto riesgo (calidad alta). La mortalidad es similar a la de la cirugía abierta y la efectividad es similar al tratamiento endoscópico (calidad alta). Conclusiones: La evidencia disponible es escasa y de baja calidad metodológica, situación que dificulta la formulación de recomendaciones. Son necesarios estudios de mejor calidad que evalúen de manera adecuada éstas técnicas

Introduction: Environmental variability of Echinococcus granulosus (Eg) has been described. 10 genotypes have been reported as well as a certain intergenotype heterogenicity in studies with material of animal origin. The aim of this study is to describe the results of an Eg genotypification protocol in samples of human hydatidosis. Materials and methods: Cross-sectional study. The hydatid fluid was collected from a consecutive sample of patients operated on for hepatic and pulmonary hydatidosis at hospitals in Temuco between July, 2004 and September, 2005. A DNA extraction protocol was designed for Eg in homogenized samples of hydatid cyst aspirate. 2 polymerase chain reaction (PCR) systems were used: PCREg9 and PCREg16; both in concentrations of 2mM MgCl2. For PCREg9, Eg9F and Eg9R primers were used at concentrations of 0.5 mM, using 35 cycles with a hybridization temperature of 60°C. For PCREg16 Eg16F and Eg16R primers were used at concentrations of 0.5 mM, using 35 cycles with a hybridization temperature of 65°C. The PCR products were absorbed with a restriction enzyme (Rsa1) in order to distinguish the genotypes. Results: 25 samples were analyzed, 4 from pulmonary cysts and 21 from hepatic cysts. Eg amplification was achieved in 22 of the 25 samples (88%). The enzymatic digestion revealed the presence of 3 possible genotypes: in 21 of 22 samples (95.45%) a restriction pattern was observed corresponding to the G1 or G7 genotypes, and the remaining samples to the G4 or G7 genotypes. Conclusion: With the PCR systems used, Eg DNA was detected

Introducción: Se ha descrito variabilidad ambiental de Echinococcus granulosus (Eg). Se han reportado 10 genotipos y cierta heterogenicidad intergenotipo en estudios con material proveniente de animales. El objetivo de este estudio es describir los resultados de un protocolo de genotipificación de Eg en muestras de hidatidosis humana. Material y método: Estudio de corte transversal. Se recolectó el líquido hidatídico de una muestra consecutiva de pacientes intervenidos quirúrgicamente por hidatidosis hepática y pulmonar en hospitales de Temuco entre julio de 2004 y septiembre de 2005. Se diseñó un protocolo de extracción de ADN para Eg en muestras homogeneizadas de aspirado de quistes hidatídicos. Se emplearon 2 sistemas de reacción de polimerasa en cadena (PCR): PCREg9 y PCREg16; ambos en concentraciones de MgCl2 al 2mM. Para PCREg9, se utilizaron los primers Eg9F y Eg9R a concentraciones de 0.5 mM, empleándose 35 ciclos con temperatura de hibridación a 60°C. Para PCREg16 se utilizaron los primers Eg16F y Eg16R a concentraciones de 0,5 mM, empleándose 35 ciclos con temperatura de hibridación a 65°C. Los productos de las PCR fueron digeridos con una enzima de restricción (Rsa1) para la discriminación de los genotipos. Resultados: Se analizaron 25 muestras, 4 provenientes de quistes pulmonares y 21 de quistes hepáticos. Se logró amplificación de Eg en 22 de 25 muestras (88%). La digestión enzimática reveló la presencia de 3 genotipos posibles: en 21 de 22 muestras (95,45%) se observó un patrón de restricción correspondiente a los genotipos G1 ó G7 y en la muestra restante a los genotipos G4 ó G7. Conclusión: Con los sistemas de PCR empleados se detectó ADN de Eg

Background: Surgery is a curative treatment for gastric cancer (GC). As relapse is frequent, adjuvant therapies such as postoperative chemo radiotherapy have been tried. In Chile, some hospitals adopted Macdonald's study as a protocol for the treatment of GC. Aim: To determine methodological quality and internal and external validity of the Macdonald study. Material and method: Three instruments were applied that assess methodological quality. A critical appraisal was done and the internal and external validity of the methodological quality was analyzed with two scales: MINCIR (Methodology and Research in Surgery), valid for therapy studies and CONSORT (Consolidated Standards of Reporting Trials), valid for randomized controlled trials (RCT). Guides and scales were applied by 5 researchers with training in clinical epidemiology. Results: The reader's guide verified that the Macdonald study was not directed to answer a clearly defined question. There was random assignment, but the method used is not described and the patients were not considered until the end of the study (36% of the group with surgery plus chemo radiotherapy did not complete treatment). MINCIR scale confirmed a multicentric RCT, not blinded, with an unclear randomized sequence, erroneous sample size estimation, vague objectives and no exclusion criteria. CONSORT system proved the lack of working hypothesis and specific objectives as well as an absence of exclusion criteria and identification of the primary variable, an imprecise estimation of sample size, ambiguities in the randomization process, no blinding, an absence of statistical adjustment and the omission of a subgroup analysis. Conclusion: The instruments applied demonstrated methodological shortcomings that compromise the internal and external validity of the

Hydatidosis is and endemic disease in the south of Chile, especially in Region IX where remain rates of high prevalence. Cholangiohydatidosis is an infrequent complication of liver hydatidosis. The objective of this paper is to describe clinical features of a series of patients with cholangiohydatidosis. Series of cases of cholangiohydatidosis treated consecutively and the corresponding follow-up is reported. Clinical, laboratory and images characteristics are described. Descriptive statistic was used and its incidence was calculated. In the studied period, 13 patients with cholangiohydatidosis were recruited, 9 men (69.2%) and 4 women (30.7%). Observed laboratory abnormalities were an increment of leukocytes in 8 patients (61.5%) and hepatic cholestasis with hepatocyte signs of cytolysis in 11 patients (84.6%). Choledocus diameter average measured by ultrasonography was 24,7 mm. All the patients had at least one liver cyst whose diameter average was of 12.1 cm. At surgery, evidence of biliary communications was detected in all patients and biliary decompression was carried out through a choledocostomy in 12 patients (92.3%) and by choledocoduodenal anastomoses in one case (7.7%). With a mean follow-up of 38.7 months morbility was 23% and mortality 7.7%. Accumulated incidence of this entity was of 0.07 cases in 5 years. Cholangiohydatidosis is an uncommon complication of liver hydatidosis that presents considerable morbidity and mortality rates.