Juan Carlos Cuevas González

VARYING THE COSTS OF SUNK COSTS: OPTIMAL AND NON-OPTIMAL CHOICES IN A SUNK-COST TASK WITH HUMANS

Twelve adult human subjects were exposed to a sunk-cost procedure with two options: a mixed-ratio schedule of points later exchangeable for money, and an escape schedule that cancelled the current trial and initiated a new one. The mixed ratio included four values, arranged probabilistically in such a way that the expected ratios favored either persistence or escape. These probabilities were varied systematically on a within-subject basis across conditions. Absolute ratio size was thus varied across four groups of three subjects each, yielding unique combinations of expected ratios from escaping and persisting. When the differences between escaping and persisting differed the least, subjects tended to persist, committing the sunk-cost error. When the differences between persisting and escaping differed by a larger margin, choice patterns tended toward optimal-escaping or persisting as a function of the contingencies. These findings demonstrate that sunk-cost decision-making errors in humans are sensitive to their relative costs and benefits, and illustrate a promising set of methods for bringing such behavior under experimental control in the laboratory.

Actinic prurigo: a case-control study of risk factors.

Actinic prurigo (AP) is an idiopathic photodermatosis that usually onsets during childhood and predominates in women. It is characterized by the symmetrical involvement of sun‐exposed areas of the skin, lips, and conjunctiva.

Determination of apoptosis in actinic prurigo by TUNEL technique

To the editor, Actinic prurigo (AP) is a chronic inflammatory disease that involves the skin, labial mucosa, and conjunctival mucosa and primarily affects mestizo and AmericanIndian populations, most of whom harbor the HLA-DR4 allele DRB1*0407 subtype (1–4). Clinically, AP manifests as bilateral and symmetrical polymorphous photodermatosis, principally affecting light-exposed areas of the face, neck, trunk, and limbs; less frequently, lesions can be seen in areas that are not exposed to solar radiation (5, 6). The dermatosis is characterized by the presence of erythematous macules and papules that aggregate into patches; because of its extremely pruritic nature, excoriations, serohematic crusts, areas of lichenification, scars, and residual hypopigmentation and hyperpigmentation are observed (5–8). The vermilion border of the lip develops edema, cracks, fissures, and ulcers that are covered by hemorrhagic crusts, and erythema can be seen in the mucosa all of which constitute AP cheilitis, a condition that accompanies AP in up to 85% of cases; in 27%, AP cheilitis appears as the only manifestation of the disease (9). By histopathology, ulceration, serohematic crusts, hyperkeratosis, acanthosis, spongiosis, vacuolization of the basal layer, and melanophages are commonly observed. The dermis shows vasodilation, edema, and a diffuse lymphocytic infiltrate; nodular-like lymphocytic formations develop in the skin, and well-defined lymphoid follicles form in the lip – all of which are pathognomonic of AP cheilitis (10), as is the presence of mastocytes, macrophages, and occasionally plasma cells. The pathophysiology is not well defined; thus, we aimed to demonstrate the presence of apoptosis. Fifty blocks with a diagnosis of AP and/or AP cheilitis that were diagnosed between 1995 and 2012 that had sufficient material were included. Twenty-two (44%) were females and 28 (56%) were males; the average age was 29.58 ± 12.30 (range: 9–55). Thirty samples were cheilitis, and 20 were AP in the skin. By histopathology with hematoxylin and eosin, we noted a perivascular inflammatory infiltrate in 30 of the AP cheilitis cases and 18 of 20 (90%) of AP cases in the skin; lymphoid follicles were observed in 20/30 (66.7%) of cheilitis cases, and nodular-like lymphocytic formations were seen in 5 (25%) AP cases in the skin. By transferase-mediated dUTP nick end labeling (TUNEL) technique, 24 cases (80%) in the lip and 16 cases (80%) in the skin showed positivity in the stratum basale; in the remaining 10 cases, there was no such expression. The stratum granulosum was positive in 23 cases (76%) in the lip and in 19 (95%) in the skin (Fig. 1); in the Photodermatology, Photoimmunology & Photomedicine

Immunohistochemistry Panel for Differential Diagnosis of Basal Cell Carcinoma and Trichoblastoma

Introduction: Basal cell carcinoma (BCC) is the most common malignant neoplasm in the skin and is considered to have a low degree of malignancy. BCC is invasive but rarely metastatic and originates in hair follicle-derived cells or interfollicular zones of the epidermis. Trichoblastoma (TB) is an infrequent benign skin neoplasm that differentiates toward follicular germinative cells. Both of these cutaneous lesions comprise nests of basaloid cells, and because the differential diagnosis is hard to obtain between them histologically due to their similarity, the correct diagnosis must be established. Materials and Methods: The sample size of this descriptive study consisted of 20 cases: 10 paraffin-embedded tissues that were diagnosed with carcinoma of solid basal cells with follicular differentiation and 10 TB tissues. The diagnosis of all samples was confirmed morphologically with hematoxylin and eosin. One-micron-thick sections were cut from each sample and analyzed semiquantitatively by immunohistochemistry (IHC). Differences in staining between BCC and TB were analyzed by Chi-square test. Results: Two of 10 TB cases were positive for Ki-67 versus 10 of 10 BCC samples. Cytokeratins 6 was expressed in 1 of 10 TB samples and in all BCC tissues. Staining with clone 34BE12 generated signals in all lesions at various intensities. Conclusion: The diagnosis between TBs and BCCs must be made histologically, because the treatment of BCC is radical and can compromise aesthetics and function, even for experienced pathologists. Because their morphological diagnosis is difficult, the histopathology results must be supported by an IHC panel.

Fibrolipomas de Cavidad Oral: Tumores Comunes en Sitios Poco Frecuentes: Reporte de Dos Casos y Revisión de la Literatura

Los lipomas son tumores mesenquimales benignos compuestos por adipocitos maduros. Corresponden a casi el 50% de los tumores de tejidos blandos, presentes entre el 1 y 5% en cavidad oral, especialmente en mucosa yugal, piso de la boca y margenes laterales de la lengua. Suelen ser asintomaticos y su color depende del espesor de la mucosa que lo cubre. Histologicamente estan conformados por lobulos de adipocitos maduros rodeados por una capsula fibrosa. Las variedades histologicas estan determinadas por el tejido adicional que contienen; los mas frecuentes son el lipoma simple y el fibrolipoma. Su curso es benigno y el tratamiento consiste en la escision quirurgica. En el presente articulo se reportan dos casos de fibrolipoma, un tumor comun en una localizacion poco frecuente.

Actinic prurigo as a hypersensitivity reaction type 4

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Estandarización en la observación y clasificación de lesiones epiteliales premalignas y malignas

Los criterios histologicos para determinar el grado de displasia, la clasificacion de Broders y el frente de invasion tumoral (FIT) son parametros subjetivos no cuantificables que pueden indicar el grado de evolucion de displasias y carcinomas. Un factor importante a considerar durante la valoracion histologica, es la variabilidad del diagnostico entre patologos. El objetivo es estandarizar los criterios y determinar la variabilidad intra e inter observador en el diagnostico de displasias y COCE. Se seleccionaron y estandarizaron los criterios morfologicos para el diagnostico y se revisaron los casos seleccionados aleatoriamente por tres patologos bucales (30 displasias y 30 carcinomas) del Laboratorio de Patologia Clinica y Experimental de la DEPeI de la FO, UNAM. Cada patologo analizo y registro los parametros establecidos para displasia, COCE y FIT en 2 ocasiones. Se aplico el test Kappa para valorar la concordancia intra e inter observador. El Observador 1 v/s el 2 obtuvo una concordancia para COCE de 0,75 y en displasias de 0,60 e intraobservador de 0,90. El observador 2 v/s el 3 presento una concordancia para COCE de 0,75 y en displasias de 0,59 e intraobservador de 0,91. El Observador 3 Vs el 1 tuvo una concordancia para COCE de 0,77, y en displasias de 0,59 e intraobservador de 0,92. La concordancia intraobservador e interobservador en COCE fue de buena a excelente, pero en displasias fue aceptable confirmando que su evaluacion presenta mayor grado de dificultad. Con una adecuada estandarizacion se puede obtener una buena concordancia entre patologos.

Intraosseous myofibroma of the mandible: a case report

El miofibroma es una neoplasia benigna compuesta por celulas mioides contractiles localizadas alrededor de la pared de vasos sanguineos delgados, es un tumor que se presenta sobre todo en la infancia aunque puede ocurrir a cualquier edad, tiene predileccion en cabeza y cuello, sin embargo en cavidad oral es raro y aun mas si es intraoseo, puede estar asociado a miofibromatosis o bien presentarse de manera solitaria. Los diagnosticos diferenciales dependen de la localizacion y de las caracteristicas radiograficas y de primera instancia es muy dificil incluir al miofibroma entre las lesiones intraoseas. Histologicamente presenta patron bifasico conformado por celulas fusiformes dispuestas en fasciculos y haces asi como nucleos fusiformes con citoplasma eosinofilo dentro de un estroma hialinizado. Es necesario recurrir al panel de inmunohistoquimica en neoplasias de celulas fusiformes, positivo a Acs Actina, Actina musculo liso y Vimentina. Reportamos el caso de una mujer de 45 ano con un miofibroma en la mandibula.

Descuento temporal y probabilístico de dinero y alcohol de usuarios en tratamiento

A strategy to study impulsive behav- ior is the procedure of discounting the relative value of rewards. It has been reported that alco- hol abusers show steeper delay or probabilistic discounting of a reward compared to people without drinking problems. The present study examined if the delay and probabilistic dis- counting rates contribute to diagnose the profile of the problem drinkers. A sample of 25 alcohol abusers completed delayed and a probabilistic discounting tasks of a certain amount of money or of their favorite drink. It was found that the delay discounting rate was slightly higher for alcohol than for the money; in the case of the probabilistic discounting task, the rates were similar for both rewards. The results of this study besides extending previous findings about the differences in the value assigned to different rewards based on their probability or delay of delivery also help to clarify the rela- tionship between the various processes in- volved in the psychological value of a reward.