RESUMEN La combinación de sarcoidosis y linfoma (síndrome sarcoidosis-linfoma) es una asociación poco frecuente pero reconocida en el ámbito clínico. Algunas manifestaciones pueden ser comunes entre estas entidades, por lo que es un reto para el clínico diferenciar cada enfermedad por separado o si coexisten en un mismo individuo. En este último escenario, ni las manifestaciones clínicas ni los parámetros de laboratorio son específicos, por lo que es necesario un análisis minucioso de cada caso, apoyado de laboratorios, imágenes e histopatología para llegar a un diagnóstico certero. Se presentan 2 casos de síndrome sarcoidosis-linfoma y se analizan los aspectos clave en el diagnóstico de esta forma clínica.

ABSTRACT The combination of sarcoidosis and lymphoma (sarcoidosis-lymphoma syndrome) is a rare but recognised clinical condition. Some manifestations may be common among these conditions, making it a challenge for the clinician to differentiate each disease separately, or if they coexist in the same individual. In this latter scenario, neither the clinical manifestations nor the laboratory parameters are specific, so a meticulous analysis of each case is necessary, supported by laboratory and imaging tests, and histopathology in order to obtain an accurate diagnosis. Two cases of sarcoidosis-lymphoma syndrome are presented, and an analysis is presented on the key aspects in the diagnosis of this clinical condition.

For many years, archaeologists have examined the Tiwanaku phenomenon outside the Titicaca basin. The research has been mainly focused on economical systems, and religious and ecological complementarity between centers and their periphery in the Andes. However, dominated by our conceptions of state and empire, those reconstructions are biased by an economic and iconographic deterministic point of view, in detriment of understanding the diversity of the Andean political phenomena. Here, we reconsider the relationship between Tiwanaku and San Pedro de Atacama through a new study of the classic black-polished pottery from the cemeteries of Solcor and Coyo, taking into account the foundational role assigned to this pottery type by different archaeologist to understand the influence of the Altiplano in the Atacama región. The results of this pottery analysis and our bioarchaeology data suggest a more heterogeneous and unequal social reality for San Pedro de Atacama as a consequence of their own local dynamics.

En las últimas décadas los arqueólogos han tendido a examinar la problemática Tiwanaku fuera del núcleo altiplánico, principalmente en términos de acceso a recursos y/o complementariedad ecológica y religiosa, entre un centro y su periferia. Sin embargo, dominados por las ideas de Estados o imperios, estas reconstrucciones adolecen de reduccionismo económico e iconográfico, en perjuicio del entendimiento de los fenómenos políticos andinos. Dentro de esta problemática, retomamos la relación entre Tiwanaku y San Pedro de Atacama a partir de un nuevo estudio de la cerámica negra pulida de los cementerios de Solcor y Coyo, en razón del carácter fundacional que Le Paige y Tarragó le imprimieron a esta alfarería para abordar el impacto altiplánico en la región. Este análisis, en conjunto con la reciente evidencia bioarqueológica obtenida por este equipo y otros, nos permiten repensar este vínculo y avanzar hacia la compresión de una realidad social mucho más dinámica, heterogénea y desigual.

El estudio comprueba que en Chile predomina la visión de frontera como el límite territorial, limitándose a una acción/visión particularmente defensiva o de economía extractiva; acción/visión que ha limitado a las políticas públicas en el marco de la globa-lización y que pese a cambios administrativos, sigue siendo centralizada. De este modo, las regiones extremas entran en un debate colectivo asimétrico con sus pares a nivel nacional en una compleja inferioridad de condiciones.

A dynamic biomass growth model for the mussel Mytilus chilensis in longline culture systems in proposed. This model determines the biomass by estimating the average weight and the number of mussels per meter of seeded rope, using real data. The average weight is estimated using the von Bertalanffy model modified to incorporate the availability of food in the environment and the reproductive cycle given by the Meat Yield Index, which is the quotient between the meat weight and the total weight. Therefore, the average weight is determined by the availability of food and the biological growth of the species. The model assumes that the number of mussel individuals per meter in the rope is the result of both the species intraspecific competition among M. chilensis individuals and the interspecific competition with individuals of the mytilid Aulacomya atra for the available space in the same seeded rope. The growth rate, the occupied surface and the presence percentage of M. chilensis and A. atra were used to model the competition for the available space. The study was performed at the Rilán basin in the Chiloé Island, southern Chile, during an 18-month period. The results obtained were an R² adjusted = 0.98, 0.93, and 0.94 for the variation in size, lineal density and biomass, respectively, which indicate that the proposed dynamic model can be used to predict the biomass over time.

Este estudio propone un modelo de crecimiento dinámico de la biomasa para el bivalvo Mytilus chilensis, en sistemas de cultivos en línea. El modelo propuesto determina la biomasa a través del peso medio total y el número de choritos por metro lineal en la cuerda de engorda, calibrado usando datos reales. El peso medio se determina a través del modelo de von Bertalanffy modificado que incorpora la disponibilidad de alimento del ambiente y el ciclo reproductivo a través del Índice de Rendimiento Productivo, el que corresponde al cociente entre el peso en carne y el peso total. Por lo anterior, el peso medio está determinado por la disponibilidad de alimento y el crecimiento biológico de la especie. El modelo supone que el número de individuos de choritos por metro en la cuerda es el resultado tanto de la competencia intraespecífica entre individuos de M. chilensis como de la interespecífica con individuos del mitílido Aulacomya atra por el espacio disponible en la misma cuerda. Para modelar la competencia por el espacio disponible se utilizó la tasa de crecimiento, la superficie ocupada por los individuos y el porcentaje de presencia de M. chilensis y de A. atra. El estudio se realizó en la cuenca de Rilán, isla de Chiloé, sur de Chile, por un periodo de 18 meses. Se obtuvo un R² ajustado = 0,98, 0,93, y 0,94 para la variación del tamaño, de la densidad lineal y la biomasa, respectivamente, lo que indica que el modelo propuesto puede ser utilizado para predecir la biomasa en el tiempo.

OBJECTIVES: To develop a model for detecting cases of organized fraud in Chile based on data from the legal forms for medically authorized leave (formulario legal de licencia médica curativa-MAL) and to establish the relevance of this data to fraud detection. METHODS: A binomial logistic regression model was employed using four variables from the MAL form, a national requirement for illness-related work absences: the number of legal absences taken by a single person, the number of days authorized by the prescribing doctor, the total cost per illness, and a dichotic variable reflecting whether or not the diagnosis is one that can be proven. The analysis involved 4 079 MAL forms that had been submitted in 2003 to a private health provider and of which 356 were already identified as fraudulent by a panel of medical fraud experts. RESULTS: The model successfully identified 99.71% of the fraudulent medical authorizations and 99.86% of the non-fraudulent, according to the criteria of the panel of fraud experts. Three of the variables employed had statistically-significant independent predictive power. The positive predictive value of the proposed model was 98.59%, while its negative predictive value was 99.97%. CONCLUSIONS: The binomial logistic model that was developed uses four variables that are common to all MAL forms in use by Chile's public as well as private insurers, permitting separation of fraudulent from non-fraudulent requests to be more accurate, more timely, and at a cost lower that of an expert panel.

OBJETIVOS: Desarrollar un modelo para detectar casos de fraude planificado en Chile a partir de los datos contenidos en los formularios de licencia médica curativa (LMC) y establecer la contribución relativa de esos datos a su detección. MÉTODOS: SE aplicó un modelo de regresión logística binominal a partir de cuatro variables contenidas en el formulario legal de LMC exigido nacionalmente para justificar las ausencias al trabajo por motivos de enfermedad: el número de licencias médicas asignadas a una misma persona, el número de días de licencia médica otorgados por el médico tratante, el monto total a pagar por la enfermedad y una variable dicotómica que refleja si el diagnóstico es comprobable o no. Se analizaron 4 079 LMC presentadas el año 2003 a una institución privada de salud previsional, de las cuales 356 estaban ya clasificadas como fraudulentas por un panel de médicos expertos en fraude. RESULTADOS: El modelo logró identificar correctamente 99,71% de las licencias médicas fraudulentas y 99,86% de las no fraudulentas según el criterio del panel de expertos en fraude. Tres de las variables empleadas presentaron un poder predictivo independiente estadísticamente significativo. El valor predictivo positivo del modelo propuesto fue de 98,59%, mientras el valor predictivo negativo fue de 99,97%. CONCLUSIONES: El modelo logístico binomial desarrollado, basado en cuatro variables de uso universal en los formularios de LMC utilizados por todas las entidades aseguradoras de Chile, tanto públicas como privadas, permite discriminar de forma precisa y más rápidamente y con menor costo que los paneles de expertos las solicitudes fraudulentas de las no fraudulentas.

Molecular recognition based on chirality has fundamental importance in many biological processes. Deuterium quadrupole splittings from the aromatic ring and mesophase components of two series of optical isomers, L- and D-N-acyl-1-phenyl-d5-2-aminopropanes, dissolved in anionic nematic cholesteric lyotropic liquid crystals of cesium N-dodecanoyl-L-threoninate, were measured using²H-NMR. The length of the acyl chain was 1, 2, 3, 4, 5, 7 and 10 carbon atoms. The two order parameters that fully characterize the average alignment of the aromatic ring were calculated. Both the L- and D- isomers are strongly attached to the aggregate. L-C1, D-C1, L-C2 and D-C2 derivatives have the same order parameters which suggests that are located in the same region of the interface, possibly H-bonded to the interstitial water molecules with the NH and/or CO groups. Increasing the hydrophobic chain length by one carbon atom decreases the overall alignment of the ring and differences between L-C3 and D-C3 were observed. Molecules with longer acyl chain progressively increase their quadrupole splittings, suggesting an increase in alignment. Increasing differences in the order parameter of the symmetry axis of the aromatic rings in both isomers were observed from C3 to C5, and almost no differentiation is detected between L-C7 and D-C7. However, differentiation appears again for C10, and is attributable to interactions with a second chiral center of the head group

Background: Norwood procedure is used as the first stage in the palliative treatment of the hypoplastic heart syndrome and can be used, with some technical modifications, in other forms of univentricular heart with aortic stenosis or hypoplasia. These patients have a high mortality (50%), derived from the procedure itself and from their abnormal physiological status. Aim: To report our experience with the Norwood procedure. Patients and methods: Retrospective analysis of all patients subjected to the Norwood procedure between February 2000 and June 2003. Results: Thirteen patients (9 females, age range 5-60 days and median weight of 3.3 kg) were operated. Eight had hypoplastic heart syndrome and five had a single ventricle with aortic arch hypoplasia. The diagnosis was done in utero in eight patients. All technical variations, according to the disposition and anatomy of the great vessels, are described. Cardiac arrest with profound hypothermia was used in all and regional cerebral perfusion was used in nine. Three patients died in the perioperative period and three died in the follow up (two, four and 10 months after the procedure). Gleen and Fontan procedures were completed in five and one patients, respectively. Conclusions: Our results with the Norwood procedure are similar to other series. There is an important mortality in the immediate operative period and prior to the Glenn procedure (Rev Méd Chile 2004; 132: 556-63).

Background: When the ascending aorta and the femoral artery cannot be used for extracorporeal circulation, an emerging alternative is the use of axillary artery. Aim: To report the experience using the axillary artery for extracorporeal circulation. Patients and methods: Between November 1998 and May 2002, 22 patients (14 male) were operated with extracorporeal circulation, cannulating the axillary artery. Briefly, an incision is made below the middle third of the clavicle and a cut is made on major pectoris muscle. Minor pectoris muscle is retracted and axillary artery is exposed. It is cannulated directly or with the aid of a prosthesis. Results: Right axillary artery was used in 21 patients and in 20 it was cannulated with the aid of a prosthesis. Mean flow was 4.5 + 0.6 l/min. The most common indications were aortic dissection or aneurysms. The most common procedures done, were ascending aorta replacement in 8 cases and replacement of ascending aorta and aortic arch in 5. Thirty five percent of operations were emergencies and 32% were reoperations. In 15 patients (68%), a circulatory arrest was done. Of these, retrograde brain perfusion was used in 9, antegrade brain perfusion through the same axillary artery was used in 2 and mixed perfusion was used in 2. One patient had a complication related to the axillary cannulation. None had cerebrovascular accidents or thromboembolic complications. Two patients died in the postoperative period. Patients were followed up to 42 months after the procedure and no secondary complications of the cannulation were detected. Conclusions: When the ascending aorta and the femoral artery cannot be used, axillary artery is a good alternative for extracorporeal circulation (Rev Méd Chile 2003; 131: 390-6).

Background: During the last five years, 65 patients with univentricular heart have been treated surgically in our institution, according to a protocol of staged operations that have been previously reported. Aim: To evaluate the early and mid-term outcome of those patients that have completed their staging protocol by means of a Fontan procedure. Patients and Methods: Between April 1996 and June 2001, 23 patients (age 16 to 223 months) underwent a Fontan procedure, 15 with an intracardiac lateral tunnel technique and 8 with an extracardiac conduit. A retrospective review of their clinical, surgical, echocardiographic, angiographic and hemodynamic data was performed, trying to identify risk factors for both mortality and functional capacity (FC). Follow up was complete in all survivors. Results: Three patients died early after surgery (13.04%). Excessive pulmonary blood flow was a risk factor for early death (p= 0.03). One patient died at 14 months. Follow up was 29.9 months (1-63). For those who survived the operation, five years survival was 93.3%. The majority of patients are in FC I or II, with no related risk factors. Conclusions: Our current results are comparable with those of larger series. Patients reach good FC and mid-term survival, irrespective of type of single ventricle or the surgical strategy (Rev Méd Chile 2002; 130: 1217-26).

Background: The implantation of pacemakers improves cardiac function and quality of life, in particular with dual chamber DDD and DDDR modes. Aim: To evaluate our clinical experience and results on pacemaker implantation, from 1963 to 1998. Material and methods: Computerized data collected from 2,445 consecutive paced patients was reviewed. A total of 3,554 operative procedures were performed, including 412 procedures for complications and 697 pacemaker replacement. Patient survival was determined from clinical records, inquiry to pacemaker manufacturers and death certificates from Servicio de Registro Civil e Identificación de Chile (Chilean Civil and Identification Registry). Results: Use of dual chamber (DDD and DDDR) pacemakers increased progressively up to 74% from 1988 to 1998. Complication rate was 42% in the 1963-1976 study period, it decreased to 10.6% in the 1977-1987 study period, and to 5.6% by 1988-1998. Only two patients died during surgery in the study period (0.08%). In the 1977-1987 period, pacemakers lasted 10.6 years. Survival rates were 52% at ten years, 33% at 15 years, and 21% at 20 years, with a median survival of 11.7 years, and 7.24 years in patients over 80 years old. Conclusions: Transvenous permanent pacing can be accomplished today with a low complication rate, mainly due to better technology and surgical procedures (Rev Méd Chile 2002; 130: 132-42)

Background. Ischemic mitral regurgitation (IMR) is a severe condition which may be best treated by surgery, nowithstanding a relatively high mortality rate. Objectives. To evaluate the results of mitral valve replacement or repair in patients with IMR. Patients and methods. Retrospective review of the clinical records in 29 patients with IMR who were surgically treated from 1990 to 1999. They represent 8% of surgical procedures on the mitral valve. Results. Mean age was 67 ± 9 years. Surgery was performed urgently in 19 patients (66,5%). NYHA functional class was 3.4 ± 0.8. The mechanism of IMR was annular dilatation and spreading of papillary muscles in 18 patients, papillary muscle rupture in 9 and fibrosis in 2. Mitral valve replacement was performed in 14 patients and mitral valve repair in 15. Twenty four patients (83%) had concomitant myocardial revascularization. Overall surgical mortality was 24%; 26% for mitral replacement and 13% for mitral valve repair (p=0.215). On follow up of 26±33 months, one year survival was 76±0.8% and 5 years survival was 59±12%. Excluding in hospital mortality, survival was 100% at one year and 78±14% at 5 years. Functional class improved in all survivors, to 1.4±0.5. Late echocardiographic evaluation of patients with mitral valve repair showed absence of mitral regurgitation in 58%, 1+ MR in 17% and 2+ MR in 25%. Conclusion. In spite of a high perioperative mortality, surgery for IMR is a valuable procedure for patients with an otherwise highly lethal disease (Rev Méd Chile 2002; 130: 9-16)

Background: Coronary artery bypass grafting (CABG) reoperation is being performed with increasing frequency. Aim: To assess the early and long term results of coronary reoperations in our institution and to identify prognostic factors. Patients and methods: 214 patients subjected to coronary reoperations between 1983 and 1999 were retrospectively studied. Results: Mean age was 64.2 years (range 42-79 years), 202 (94.4%) were male and 12 (5.6%) female. The mean interval between the operations was 125.7 months (range 6-252 months). 10 (4,6%) were emergency surgeries. Overall operative mortality was 5.6% (11 deaths) and in 5 patients (3.4%) a perioperative myocardial infarction was noted. Univariate analysis identified moderate or severe left ventricular failure (p=0.048) as predictor of increased operative mortality, meanwhile age over 75 years (p=0.02) and moderate or severe left ventricular failure (p=0.01) were identified as predictors of increased in hospital mortality in the multivariate analysis. Follow up of in hospital survivors (mean interval 65 months, range 4 to 190 months) documented a 5 years survival rate of 82.9%, a 10 years survival rate of 73.1% and a 15 years survival rate of 53.4%. Moderate or severe left ventricular failure (p <0.0001) and emergency surgeries (p=0.007) were identified as factors influencing the late survival in the stepwise logistical regression analysis. Multivariate analysis identified left ventricular failure (p=0.01) and peripheral vascular disease (p=0.01) as predictors of decreased late survival. Conclusions: Coronary reoperation has a low mortality in patients with a normal ventricular function and also has an excellent overall and disease free survival in the first 10 years of follow up. Left ventricular function is an independent risk factor increasing in hospital and late mortality (Rev Méd Chile 2001; 129: 1131-41)

Background: Surgical repair is the procedure of choice for mitral insufficiency since it preserves better left ventricular structure and function. Aim: To assess the long term clinical and echocardiographic results of mitral valve reconstructive surgery. Material and methods: A review of clinical and echocardiographic data of 68 patients (34 male, age range 17 to 82 years), subjected to surgical mitral valve repair between December 1991 and March 1998. Preoperative functional capacity of these patients was 2.96 ± 0.7. Surgical repair was assessed using transesophagic echocardiography in all subjects. Results: The etiology of mitral insufficiency was degenerative in 43 patients, rheumatic in 10, infectious in 6, ischemic in 5 and miscellaneous in 4. The most frequent pathological findings were dilatation of the mitral ring in 42% of patients, chordae tendinae rupture in 32% and enlargement in 24%. A mitral anuloplasty was done in 90% of patients, a cuadrilateral resection of posterior leaflet in 52% and chordae tendinae transference in 12%. An additional surgical procedure was done in 34% of subjects. Three patients died during hospitalization (4.4%). During the follow up of 36.5 ± 22.3 months, five patients died and one required a mitral valve replacement. The actuarial survival probability was 95.3 ± 2.6% at one year and 83.5 ± 6.5% at five years. The reoperation free survival was 100% at one year and 97.4 ± 2.5% at five years. At the end of follow up the functional capacity improved to 1.25 ± 0.4. Echocardiography showed absence of mitral insufficiency in 48.4% of patients, minimal, mild and moderate insufficiency in 35.5, 14.5 and 1.6% of patients respectively. Conclusions: Surgical valve reconstruction in mitral insufficiency has satisfactory long term results and should be the procedure of choice for eligible patients.