Héctor Losada
University of La Frontera
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Featured researches published by Héctor Losada.
Modern Pathology | 2011
Juan Carlos Roa; Oscar Tapia; Asli Cakir; Olca Basturk; Nevra Dursun; Deniz Akdemir; Burcu Saka; Héctor Losada; Pelin Bagci; N. Volkan Adsay
The information in the literature on squamous cell and adenosquamous carcinomas of the gallbladder is highly limited. In this study, 606 resected invasive gallbladder carcinoma cases were analyzed. Squamous differentiation was identified in 41 cases (7%). Those without any identifiable glandular-type invasive component were classified as pure squamous cell carcinomas (8 cases) and those with the squamous component constituting 25–99% of the tumors were classified as adenosquamous carcinomas (26 cases) and included into the analysis. The remaining 7 that had <25% squamous component were classified as adenocarcinoma with focal squamous change and excluded. The clinicopathological characteristics of adenosquamous carcinoma/squamous cell carcinomas were documented and contrasted with that of ordinary gallbladder adenocarcinomas. The average patient age was 65 years (range 26–81); female/male ratio, 3.8. In only 13%, there was a preoperative clinical suspicion of malignancy. Grossly, 58% presented as thickening and hardening of the wall and 6% were polypoid. In 12%, mucosa adjacent to the tumor revealed squamous metaplasia. All pure squamous cell carcinomas had prominent keratinization. Giant cells and tumor-infiltrating eosinophils were observed in 29 and 51% of the squamous cell carcinomas/adenosquamous carcinomas versus 10% (P=0.02) and 6% (P=0.001) in gallbladder adenocarcinomas, respectively. All but three cases had ‘advanced’ (pT2 and above) carcinomas. Follow-up was available in 31 patients: 25 died of disease (median=5 months, range 0–20), and 6 were alive (median=64 months, range 5–112.5). The survival of patients with squamous cell carcinomas/adenosquamous carcinomas was significantly worse than that of gallbladder adenocarcinomas (P=0.003), and this adverse prognosis persisted when compared with stage-matched advanced gallbladder adenocarcinoma cases (median=11.4 months, P=0.01). In conclusion, squamous differentiation was noted in 7% of gallbladder carcinomas. The incidence of adenosquamous carcinoma (defined as 25–99% of the tumor being squamous) was 4%, and that of pure squamous cell carcinoma (without any documented invasive glandular component) was 1%. Pure squamous cell carcinomas often showed prominent keratinization. The overall prognosis of adenosquamous carcinoma/squamous cell carcinoma appears to be even worse than that of ordinary adenocarcinomas. Most patients died within a few months; however, those few who were alive beyond 2 years in this cohort experienced long-term survival.
Journal of Gastrointestinal Surgery | 2006
Xabier De Aretxabala; Iván Roa; L. Burgos; Héctor Losada; Juan Carlos Roa; Javier Mora; Juan Hepp; Jorge Leon; Fernando Maluenda
The goal was to study our experience in the management of a series of patients with a potentially curative subserosal gallbladder cancer who were prospectively treated by the authors. Between April 1988 and July 2004, 139 patients were enrolled in our prospective database. Of the above, 120 were operated on with an open procedure and the rest with laparoscopic surgery. In only eight patients was the diagnosis suspected before the cholecystectomy. The majority of tumors were adenocarcinoma. Six patients had an epidermoid tumor, and one had a carcinosarcoma. Of the patients, 74 underwent reoperation, while in 55 (70.2%) it was possible to perform an extended cholecystectomy with a curative aim. Operative mortality was 0%, and operative morbidity was 16%. Lymph node metastases were found in 10 (18.8%), while in 7 (13.2%) the liver was involved. The overall survival rate was 67.7%, while in those who underwent resection, the survival rate was 77%. Through the use of a multivariate analysis, the presence of lymph node metastasis was found to be an independent factor with respect to prognosis. The feasibility of performing an extended cholecystectomy in patients with gallbladder cancer and invasion of the subserosal layer allows for a good survival rate. The presence of lymph node metastases represents the main poor prognosis factor, and some type of adjuvant therapy should be studied in this particular group.
Annals of Surgery | 2006
Carlos Manterola; Viviana Pineda; Manuel Vial; Héctor Losada
Objective:To determine the methodologic quality of therapy articles about humans published in ISI surgical journals, and to explore the association between methodologic quality, origin, and subject matter. Summary Background Data:It is supposed that ISI journals contain the best methodologic articles. Methods:This is a bibliometric study. All journals listed in the 2002 ISI under the subject heading of “Surgery” were included. A simple randomized sampling was conducted for selected journals (Annals of Surgery, The American Surgeon, Archives of Surgery, British Journal of Surgery, European Journal of Surgery, Journal of the American College of Surgeons, Surgery, and World Journal of Surgery). Published articles related to therapy on humans of the selected journals were reviewed and analyzed. All kinds of clinical designs were considered, excluding editorials, review articles, letters to the editor, and experimental studies. The variables considered were: place of origin, design, and the methodologic quality of articles, which was determined by applying a valid and reliable scale. The review was performed interchangeably and independently by 2 research teams. Descriptive and analytical statistics were used. Statistical significance was defined as P values less than 1%. Results:A total of 653 articles were studied. Studies came predominantly from the United States and Europe (43.6% and 36.8%, respectively). The subject areas most frequently found were digestive and hepatobiliopancreatic surgery (29.1% and 24.5%, respectively). Average and median methodologic quality scores of the entire series were 11.6 ± 4.9 points and 11 points, respectively. The association between methodologic quality and journals was determined. Also, the association between methodologic quality and origin was observed, but no association with subject area was verified. Conclusions:The methodologic quality of therapy articles published in the journals analyzed is low; however, statistical significance was determined between them. Association was observed between methodologic quality and origin, but not with subject matter.
Obesity Surgery | 2005
Carlos Manterola; Viviana Pineda; Manuel Vial; Héctor Losada; Sergio Muñoz
Background: Bariatric surgery is the therapy for morbid obesity. There are a number of surgical procedures, which are performed by open surgery (OS) and more recently also by laparoscopy (LS). The objective of this study was to consider the evidence for the best bariatric surgical options. Methods: Systematic review of the literature was conducted. Morbid obesity studies published between 1990 and 2002 were analyzed. MEDLINE, LiLACS and COCHRANE databases were used, utilizing MeSH terms and free words. Selected studies were analyzed using a specially designed score of methodological quality, to analyze and compare studies. This validated scale is composed by 3 items, and the final score may range between 6 and 36 points. Means, medians and weighted means were calculated, and a comparative analysis by therapy was performed using median 95% confidence intervals (CI). Number of treated patients, reduction in body mass index (BMI), reduction in co-morbidity, %EWL, morbidity and mortality, hospital stay, follow-up, success and failure of operations, and methodological quality were analyzed. Results: 283 related articles were considered. Only 31 of them had selection criteria (these include 5,216 patients operated by OS and 3,230 by LS). Operative mortality was 0.0% for OS and 0.4% for LS. At 36 months, OS techniques show reduction in BMI, %EWL and reductions in co-morbidity of 30.9%, 61.9% and 74.1% respectively. At 36 months, LS techniques show reduction in BMI, %EWL and reduction in comorbidity of 23.7%, 55.9% and 70.9%. Hospital stay was 3.8 days for LS and 7 for OS. At 2-year follow-up, morbidity was 14.8% for LS and 16.7% for OS, and reoperations were 17.7% for LS and 11.3% for OS.Median score for methodological quality was 13 for OS and 11 for LS. Conclusions: Methodological quality of primary studies to 2002 has been poor.
Anz Journal of Surgery | 2003
Carlos Manterola; Manuel Barroso; Manuel Vial; Luis Bustos; Sergio Muñoz; Héctor Losada; Nelson Bello; Francisco Hernández
Background: Cyst infection and subsequent liver abscess formation are complications of liver echinococcosis. Traditionally, this condition has been treated by simple drainage, a procedure associated with unsatisfactory postoperative evolution.
Tropical Doctor | 2004
Carlos Manterola; Rodolfo Espinoza; Sergio Muñoz; Manuel Vial; Luis Bustos; Héctor Losada; Manuel Barroso
Twelve pregnant women with hydatid disease are presented with median age of 29;11 (91.7%) had a liver cyst and one (8.3%) had a kidney cyst as the primary disease location. Four (33.3%) had additional cysts located in the pelvis, peritoneal cavity and/or spleen; eight (66.7%) had two or more abdominal cysts. Three patients (25.0%) had surgery at the 3rd month after delivery and nine (75.0%) during their pregnancy. There was no histological evidence of hydatid disease in placentas, and no serological evidence of echinococcosis in the newborns was confirmed. One patient died after surgery. After a mean follow-up time of 39.5 months, we found one recurrent case of pelvic hydatid disease. Management of abdominal echinococcosis during pregnancy is an uncommon and difficult problem owing to the serious potential risks for mother and child.
Archives of Pathology & Laboratory Medicine | 2012
Nevra Dursun; Oscar Tapia Escalona; Juan Carlos Roa; Olca Basturk; Pelin Bagci; Asli Cakir; Jeanette D. Cheng; Juan M. Sarmiento; Héctor Losada; So Yeon Kong; Leslie Ducato; Michael L. Goodman; N. Volkan Adsay
CONTEXT There are virtually no data in the literature regarding the incidence, patterns, and clinicopathologic characteristics of mucinous carcinomas (MCs) of the gallbladder (GB). OBJECTIVE To determine the incidence of mucinous differentiation in invasive GB carcinomas and the clinicopathologic characteristics of those that qualify as MC. DESIGN Primary invasive GB carcinomas (n = 606) were reviewed for mucinous differentiation. Some degree of mucin production was identified in 40 cases (6.6%); however, only 15 (2.5%) were qualified for the World Health Organization definition of MC (stromal mucin deposition constituting >50% of the tumor). RESULTS The mean age was 65 years, and the female to male ratio was 1.1 (versus 3.9 for conventional pancreatobiliary-type GB adenocarcinomas; P = .04). A significant proportion of the cases (8 of 12, 67%) presented with the clinical picture and intraoperative findings that were interpreted as acute cholecystitis. Mean and median tumor sizes were larger than those of conventional adenocarcinomas (4.8 and 3.4 cm versus 2.9 and 2.5 cm, respectively; P = .01). Most (13 of 15, 87%) cases presented with pT3 tumors (versus 48% for ordinary GB carcinomas; P = .01). Two cases had almost an exclusive colloid pattern (>90% composed of well-defined stromal mucin nodules that contained scanty carcinoma cells, most of which were floating within the mucin). Eight cases were of mixed-mucinous type, showing a mixture of colloid and noncolloid patterns. Five others had prominent signet-ring cells, both floating within the mucin (which constituted >50% of the tumor by definition) and infiltrating into the stroma as individual signet-ring cells in some areas. Immunohistochemical analysis performed on the 7 cases that had available tissue revealed CK7 in 4 of 7 (57%), CK20 in 2 of 7 (29%), MUC1 in 4 of 7 (57%), MUC2 in 6 of 7 (86%), CDX2 in 1 of 7 (14%), MUC5AC in 6 of 7 (86%), MUC6 in 0 of 7 (0%), and loss of E-cadherin in 6 of 7 (86%). The MLH1 and MSH2 were retained in 6 of 7 cases (100%). Follow-up information was available for 13 cases: 11 (85%) died of disease (1-37 months) and 2 (15%) were alive (23 months and 1 month). Overall survival of MCs was significantly worse than that of conventional adenocarcinomas (13 versus 26 months; P = .01); however, that did not seem to be independent of stage. CONCLUSIONS Mucinous carcinomas constitute 2.5% of GB carcinomas. They present with an acute cholecystitis-type picture. Most MCs are a mixed-mucinous, not pure colloid, type. They are typically large and advanced tumors at the time of diagnosis and thus exhibit more-aggressive behavior than do ordinary GB carcinomas. Immunophenotypically, they differ from conventional GB adenocarcinomas by MUC2 positivity, from intestinal carcinomas by an often inverse CK7/20 profile, from pancreatic mucinous carcinomas by CDX2 negativity, and from mammary colloid carcinomas by a lack of MUC6. Unlike gastrointestinal MCs, they appear to be microsatellite stable.
Boletín chileno de parasitología | 2001
Carlos Manterola; Héctor Losada; Sergio Muñoz; Luis Bustos; Manuel Vial; Giulio Innocenti
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 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.
Tropical Doctor | 2003
Carlos Manterola; Manuel Vial; Héctor Losada; Flery Fonseca; Luis Bustos; Sergio Muñoz; Manuel Barroso
South Chile is an endemic zoonosis area of hydatid disease, where prevalence rates can be 30 to 40/100 000 habitants. Not only is surgery performed on a great number of liver and lung hydatid cysts every year, but also upon cysts found in uncommon abdominal locations such as spleen, peritoneum and kidney. Information on this subject is scarce. We reviewed PubMed index from 1975 to 2001 and found only five related articles, reporting more than 30 cases.
Cirugia Espanola | 2005
Carlos Manterola; Viviana Pineda; Manuel Vial; Héctor Losada
Resumen Introduccion El objetivo de este estudio es determinar la asociacion entre el factor de impacto (FI) de las revistas quirurgicas y el grado de evidencia de los articulos publicados en ellas sobre procedimientos terapeuticos. Material y metodo Estudio bibliometrico. Se incluyeron revistas quirurgicas registradas en ISI ® 2002, que fueron agrupadas segun el percentil 33 de su FI en: grupo 1 (0,128 a 1,690), grupo 2 (1,691 a 2,886) y grupo 3 (2,887 a 6,674). Se aplico un muestreo aleatorio simple de las revistas de cada grupo, con lo que los grupos quedaron conformados por: grupo 1: European Journal of Surgery, American Surgeon y World Journal of Surgery ; grupo 2: Journal of the American College of Surgeons, Surgery y Archives of Surgery ; y grupo 3: The British Journal of Surgery y Annals of Surgery . Los articulos fueron analizados de forma cruzada e independiente por 2 equipos de revisores. Resultados Un total de 751 articulos estaba relacionado con la terapeutica (41,2%). El FI promedio de los grupos en estudio fue 1,66 ± 0,48 para el grupo 1; 2,61 ± 0,15 para el grupo 2 y 4,69 ± 1,57 para el grupo 3 (p Conclusiones Se verifico la asociacion entre el FI de las revistas quirurgicas y el grado de evidencia en publicaciones relacionadas con la terapeutica.