Contribution of nursing students to clinical settings: A multi center cross sectional study.

AIMS: To describe the contribution of nursing students to clinical settings based on the perceptions of nurse preceptors and to examine whether certain characteristics of nurses' professional activity are associated with a positive perception of nursing students. BACKGROUND: Most clinical agencies receive many nursing students each year, who acquire clinical competencies under the guidance of a registered nurse preceptor. However, there is limited evidence of the contributions made by nursing students during clinical placements. METHODS: A multi-center cross-sectional study was carried out between June and December 2019. A convenience sample of Registered Nurses (n = 927) was recruited from four public hospitals in Spain. The Nursing Student Contributions to Clinical Settings' questionnaire was used. In addition, sociodemographic, work and teaching activity variables were collected. Multivariable logistic regression was used to determine the variables associated with positive student contributions. RESULTS: The nursing student contributions were deemed favorable by 70.7% of the nurse preceptors, mainly because the nursing students are future professionals who know the center, support the development of the nurses' teaching role and constitute a link between the health center and the university. Certain professional characteristics of the Registered Nurses were significantly associated with a positive perception of the contributions of nursing students: having daily coffee breaks (Odds ratio: 2.60; 95% Confidence interval:1.27-5.32), high levels of professional satisfaction (Odds ratio: 2.13; 95% Confidence interval:1.21-3.75) and work in medical-surgical units (Odds ratio: 1.62; 95% Confidence interval: 1.08-2.41). In contrast, nurses with greater work experience (≥ 30 years) (Odds ratio: 0.48; 95% Confidence interval: 0.27-0.85) and who worked at units where 10 or more students perform clinical practice (Odds ratio: 0.57; 95% Confidence interval: 0.36-0.90) were associated with a lower probability of positive perceptions. CONCLUSIONS: In Spain, the contributions made by nursing students to clinical settings are favorable, both for the nursing profession and for healthcare institutions. Their contributions are influenced by the professional characteristics of the Registered Nurses, as well as the environment and the teaching activity within the units.

Proteínas oxidadas de origen animal y su impacto sobre la salud intestinal / Oxidized proteins of animal origin and their impact on intestinal health / Proteínas oxidadas de origem animal e seu impacto na saúde intestinal

Los alimentos de origen animal como la carne de pollo, res, pescado y cerdo poseen una amplia demanda en todo el mundo debido, entre otros aspectos, a su valor nutricional, asociado al alto contenido proteico. No obstante, este tipo de proteínas son susceptibles de sufrir reacciones de oxidación, las cuales pueden mediar procesos de fragmentación, agregación, pérdida de solubilidad, funcionalidad y digestibilidad proteica; eventos implicados en la pérdida de su valor nutricional. En este sentido, las proteínas agrega­das tienden a no ser digeridas en el tracto gastrointestinal y acumularse en el intestino (colon), donde la microbiota colónica las degrada a productos mutagénicos como fenol y p-cresol, lo que incrementa el riesgo de cáncer colorrectal. Por otra parte, los ami­noácidos o péptidos oxidados liberados en la digestión podrían incorporarse en las vías de señalización celular intestinal y favorecer o exacerbar procesos intestinales crónicos como colon irritable o enfermedad de Crohn. Debido al gran interés de esta temática en los últimos años, el objetivo de esta revisión es realizar una descripción general del impacto de proteínas oxidadas de origen animal sobre la salud intestinal.

Animal foods such as chicken, beef, fish and pork are in wide demand throughout the world due, among other things, to their nutritional value, associated with their high protein content. However, this type of protein is susceptible to oxidation reactions, which can mediate processes of fragmentation, aggregation, loss of solubility, functionality, and protein digestibility, which are events involved in the loss of their nutritional value. In this sense, aggregated proteins tend not to be digested in the gastrointestinal tract and accumulate in the intestine (colon), where the colonic microbiota degrades them into mutagenic products such as phenol and p-cresol, which increases the risk of colorectal cancer. On the other hand, the oxidized amino acids or peptides released in digestion could be incorporated into intestinal cell signaling pathways and favor or exacerbate chronic intestinal processes such as irritable bowel syndrome or Crohn's disease. Due to the great interest in this topic in recent years, the objective of this review is to provide a general overview of the impact of oxidized proteins of animal origin on intestinal health.

Alimentos de origem animal como frango, carne bovina, peixe e carne suína são muito procurados em todo o mundo devido, entre outros fatores, ao seu valor nutricional, associado ao seu alto teor de proteínas. No entanto, esse tipo de proteína é suscetível a reações de oxidação, que podem mediar processos de fragmentação, agregação, perda de solubilidade, funcionalidade e digestibilidade da proteína; eventos envolvidos na perda de seu valor nutritivo. Nesse sentido, as proteínas agregadas tendem a não ser digeridas no trato gastrointestinal e se acumulam no intestino (cólon), onde a microbiota colônica as degrada em produtos mutagênicos como fenol e p - cresol, aumentando o risco de câncer colorretal. Por outro lado, os aminoácidos ou peptídeos oxidados liberados na digestão poderiam ser incorporados às vias de sinalização das células intestinais e favorecer ou exacerbar processos intestinais crônicos, como a síndrome do intestino irritável ou a doença de Crohn. Devido ao grande interesse neste tema nos últimos anos, o objetivo desta revisão é fornecer uma descrição geral do impacto das proteínas oxidadas de origem animal na saúde intestinal.

Contributions of nursing students during their clinical practice in primary care: Adaptation and validation of a scale.

AIM: To adapt the 'Nursing Student Contributions to Clinical Settings' scale (CEEEC, Spanish acronym), designed for specialized care and to evaluate the validity and reliability of a measure in the primary health care setting. Additionally, a description of the contributions of nursing students to primary health care in Spain is presented, based on the perception of preceptor nurses. METHODS: A multicenter cross-sectional study was conducted in Spain, involving a committee of nursing experts who participated in a Delphi panel (n = 5) and cognitive interviews (n = 5) and a sample of nursing preceptors (n = 300) from 57 primary health care centers (2019-2020). The CEEEC was reviewed by experts for the conceptual semantic adequacy of the 24 items for its application in primary health care. Nurse preceptors' responses to the CEEEC scale were used to study the validity and reliability of the measure, including factor analysis, convergent validity with the Health Sciences-Evidence Based Practice scale and a matched test-retest over a three-week interval. RESULTS: According to the consensus of experts, the CEEEC scale is valid for primary health care with minimal modifications (change "patient" to "user"). Based on the analysis of responses to the scale, the corrected item-total correlations of the 24 items were ≥ 0.40 and were grouped into a single factor, explaining 46.3% of the variance. The Cronbach's alpha value was 0.95. Regarding convergent validity, there was a positive correlation between the CEEEC scale and the score of the Health Sciences-Evidence Based Practice scale (Pearson's coefficient= 0.33; p < 0.001). The overall intraclass correlation coefficient was 0.91. Finally, the mean CEEEC score was 61.9 points (range 0-96). The two most positive contributions were 'Nursing students enable nursing professionals to perform their teaching role' and 'Nursing students become future professionals who know the healthcare facility'. CONCLUSIONS: The CEEEC scale provides a valid and reliable measure of nursing students' contributions to primary health care. Nursing students' contributions to Spanish primary health care were positive, especially towards the nursing profession and healthcare organizations.

Haptic simulation of tissue tearing during surgery.

We present a method for the real-time, interactive simulation of tissue tearing during laparoscopic surgery. The method is designed to work at haptic feedback rates (ie, around 1 kHz). Tissue tearing is simulated under the general framework of continuum damage mechanics. The problem is stated as a general, multidimensional parametric problem, which is solved by means of proper generalized decomposition methods. One of the main novelties is the reduction of history-dependent problems, such as damage mechanics, by resorting to an approach in which a reduced-order field of initial damage values is considered as a parameter of the formulation. We focus on the laparoscopic cholecystectomy procedure as a general example of the performance of the method.

Real-time simulation of biological soft tissues: a PGD approach.

We introduce here a novel approach for the numerical simulation of nonlinear, hyperelastic soft tissues at kilohertz feedback rates necessary for haptic rendering. This approach is based upon the use of proper generalized decomposition techniques, a generalization of PODs. Proper generalized decomposition techniques can be considered as a means of a priori model order reduction and provides a physics-based meta-model without the need for prior computer experiments. The suggested strategy is thus composed of an offline phase, in which a general meta-model is computed, and an online evaluation phase in which the results are obtained at real time. Results are provided that show the potential of the proposed technique, together with some benchmark test that shows the accuracy of the method.

Clasificación de materiales plásticos sanitarios desechables y búsqueda de alternativas sin policloruro de vinilo en el Hospital Virgen de las Nieves / Classification of disposable medical plastics and search for alternatives without polyvinyl chloride in the Hospital Virgen de las Nieves (Granada, Spain)

Objetivos. identificación y clasificación de los productos hospitalarios desechables que contengan policloruro de vinilo (PVC), integrando la búsqueda y valoración de productos alternativos libres de PVC sustentables desde un punto de vista coste/efectivo. Métodos. análisis de tipo descriptivo observacional. Se realizó en primer lugar una clasificación de los trabajos de investigación más recientes en las principales bases de datos. Seguidamente, se clasificaron los productos desechables susceptibles de contener PVC, dividiéndolos en 5 grupos: cánulas, sondas, tubos, bolsas y equipos enmarcados en el periodo de consumo 2008-2009, diferenciando la valoración técnica y económica de los materiales. Resultados. en el estudio se observa que de los 492 artículos analizados en su composición, 234 (47,5%) contienen PVC y las alternativas libres del compuesto conforman el 19,4%, siendo viable económicamente solo el 11,3% de las alternativas valoradas. Conclusiones. la investigación aclara las ventajas derivadas de la clasificación de productos con PVC, existiendo alternativas seguras y eficientes para algunas líneas de productos, en consonancia con la seguridad de los pacientes y la calidad en el trabajo por parte de los facultativos (AU)

Objectives. To identify and classify disposable hospital products containing polyvinyl chloride (PVC), including the search and evaluation of cost-effective sustainable alternative products free of PVC. Methods. A descriptive observational analysis was performed, after classifying the latest research in major databases, and disposable products that could contain PVC. These were divided into 5 groups: cannulas, catheters, tubes, bags, and equipment, purchased in the period 2008-2009, differentiating between the technical and economic assessment of the materials. Results. In the analysis of the composition of 492 articles selected, 234 (47.5%) contained PVC, and 19.4% were considered PVC-free alternatives, with only 11.3% of these being economically viable. Conclusions. This study highlights the advantages of the classification of PVC products, by showing that safe and efficient alternatives exist for some product lines that are consistent with patient safety and quality in the work by doctors (AU)

[Classification of disposable medical plastics and search for alternatives without polyvinyl chloride in the Hospital Virgen de las Nieves (Granada, Spain)]. / Clasificación de materiales plásticos sanitarios desechables y búsqueda de alternativas sin policloruro de vinilo en el Hospital Virgen de las Nieves.

OBJECTIVES: To identify and classify disposable hospital products containing polyvinyl chloride (PVC), including the search and evaluation of cost-effective sustainable alternative products free of PVC. METHODS: A descriptive observational analysis was performed, after classifying the latest research in major databases, and disposable products that could contain PVC. These were divided into 5 groups: cannulas, catheters, tubes, bags, and equipment, purchased in the period 2008-2009, differentiating between the technical and economic assessment of the materials. RESULTS: In the analysis of the composition of 492 articles selected, 234 (47.5%) contained PVC, and 19.4% were considered PVC-free alternatives, with only 11.3% of these being economically viable. CONCLUSIONS: This study highlights the advantages of the classification of PVC products, by showing that safe and efficient alternatives exist for some product lines that are consistent with patient safety and quality in the work by doctors.

Real-time simulation of surgery by reduced-order modeling and X-FEM techniques.

This paper describes a novel approach for the simulation of surgery by a combined technique of model order reduction and extended finite element method (X-FEM) methods. Whereas model order reduction techniques employ globally supported (Ritz) shape functions, a combination with X-FEM methods on a locally superimposed patch is developed for cutting simulation without remeshing. This enables to obtain models with very few degrees of freedom that run under real-time constrains even for highly non-linear tissue constitutive equations. To show the performance of the technique, we studied an application to refractive surgery in the cornea.

Accounting for large deformations in real-time simulations of soft tissues based on reduced-order models.

Model reduction techniques have shown to constitute a valuable tool for real-time simulation in surgical environments and other fields. However, some limitations, imposed by real-time constraints, have not yet been overcome. One of such limitations is the severe limitation in time (established in 500Hz of frequency for the resolution) that precludes the employ of Newton-like schemes for solving non-linear models as the ones usually employed for modeling biological tissues. In this work we present a technique able to deal with geometrically non-linear models, based on the employ of model reduction techniques, together with an efficient non-linear solver. Examples of the performance of the technique over some examples will be given.

Real-time deformable models of non-linear tissues by model reduction techniques.

In this paper we introduce a new technique for the real-time simulation of non-linear tissue behavior based on a model reduction technique known as proper orthogonal (POD) or Karhunen-Loève decompositions. The technique is based upon the construction of a complete model (using finite element modelling or other numerical technique, for instance, but possibly from experimental data) and the extraction and storage of the relevant information in order to construct a model with very few degrees of freedom, but that takes into account the highly non-linear response of most living tissues. We present its application to the simulation of palpation a human cornea and study the limitations and future needs of the proposed technique.

Dimensiones de los trastornos de la personalidad y correlatos neurofisiológicos / Dimensions of personality disorders and neurophysiological correlates

Introducción. El objetivo es identificar la estructura factorial que subyace a los trastornos de la personalidad utilizando medidas clínicas y de la personalidad y comprobar si la estructura resultante es válida o teóricamente comprensible utilizando medidas neurocognitivas y psicofisiológicas para establecer las posibles diferencias existentes entre los factores. Método. A partir de los datos obtenidos con las escalas MCMI-II y BFQ en una muestra de 87 sujetos diagnosticados de alguna de las categorías clínicas de los trastornos de la personalidad del DSM-IV y 17 controles normales se realizaron análisis factoriales de primero y segundo orden. Resultados. Se obtuvieron cinco factores de primer orden (denominados personalidad agresiva, personalidad con déficit social, personalidad no patológica, personalidad obsesiva y personalidad no asertiva) y tres factores de segundo orden (personalidad con déficit social/no asertiva, personalidad agresiva y personalidad no patológica/obsesiva). Conclusiones. En el análisis de la relación existente entre los factores de segundo orden y las medidas neurocognitivas y psicofisiológicas se encontró que las personalidades socialmente inhibidas y no asertivas (factor 1) se caracterizaron por déficit neuropsicológicos específicos en la atención sostenida, que las personalidades agresivas (factor 2) se caracterizaron por la impulsividad y el déficit en la formación de conceptos y que las personalidades no patológicas con rasgos obsesivos (factor 3), presentaban un nivel progresivamente menor de eficacia en tareas de atención sostenida y una mayor respuesta psicogalvánica al estrés a medida que los rasgos de obsesividad aumentaban

Introduction. To objective is to identify the factorial structure underlying personality disorders, using clinical and personality measures, and to check whether the resulting structure is valid and theoretically comprehensible, using neurocognitive and psychophysiological measures for establishing possible differences between the factors. Method. From the data obtained with the scales MCMI-II and BFQ administered to a sample of 87 subjects diagnosed as a case of any clinical category of DSM-IV personality disorders, and 17 normal controls, we carried out first-order and second-order factor analyses. Results. Five first-order factors (designated as aggressive personality, personality with social deficit, non-pathological personality, obsessive personality and non-assertive personality) and three second-order factors (non-pathological/obsessive personality) were found. Conclusions. On studying the second-order factors in relation to neurocognitive and psychophysiological measures, it was found that socially-inhibited and non-assertive personalities (factor 1) are characterized by specific neuropsychological deficits in sustained attention; that aggressive personalities (factor 2) are characterized by impulsiveness and deficit in concepts formation; and that in non-pathological personalities with obsessive traits (factor 3), as obsessiveness increases, subjects present less efficacy in sustained attention tasks and greater psychogalvanic response to stress

Sindrome de zollinger-ellison: análisis de tres casos / Zollinger-ellison syndrome: analysis of three case

Los gastrinomas están entre los tumores neuroendocrinos pancreáticos más frecuentes, y el 60 por ciento son malignos. Al momento del diagnóstico el 50 por ciento ya presentan matástasis aunque se trata de lesiones de bajo grado de malignidad, y el 60 por ciento de estas lesiones se originan en lugares extrapancreáticos. Los tres casos que se analizaron demostraron la utilidad de los niveles de gastrina seriados, la ecoendoscopia y la sintigrafía para receptores de somatostatina marcados con Indio 111 en la detección de lesiones metastásicas

Validation of a questionnaire to evaluate the attitude towards primary prevention advice from the European code against cancer.

Educative interventions to promote primary prevention of cancer (PPC) should be based on psychosocial models and be tailored to attitude. Attitude is a difficult variable to measure. The aim of this study was to draw up a questionnaire to evaluate the attitude to PPC of relatives of patients affected by cancer. An interview of 48 patients, who answered open questions, allowed 67 items to be drawn up. Three hundred and fifty-five people answered the self-administered questionnaire of 67 items (69 of them did it twice, with an interval of 2 weeks). The factorial analysis revealed five factors that explain the 36% total and the 115% common estimated variance. The Cronbach's alpha oscillated between 0.80 and 0.93. The intraclass correlation coefficient was 0.7721 (95% CI (confidence interval) 0.6311-0.8592, P<0.0001). The analysis based on Samejima's model ordered the items according to their discriminating power and the difficulty/ease with which people agree with the most preventive option. The average scores obtained in both surveys of 69 people did not show significant statistical differences (P=0.195). The definitive questionnaire obtained has 63 items that measure attitude to PPC behaviour in a reliable and stable way.

Morbilidad y recurrencia de la disección inguino-femoral con incisión limitada en carcinoma epidermoide de vulva / Morbidity and recurrence of the inguino-femoral dissection with limited incision in epidermoid vulvar carcinoma

Tradicionalmente la disección radical ganglionar inguinal ha sido el tratamiento en el carcinoma de vulva, sin embargo, la morbilidad asociada al procedimiento es alta. Recientemente se han propuesto nuevas opciones en el manejo. De tal manera que tanto los procedimientos radicales versus conservadores no han demostrado diferencias en la supervivencia. Objetivo. Comparar la morbilidad y recurrencia tumoral entre dos tipos de abordajes para la disección ganglionar inguino-femoral mediante incisiones cl sicas radicales versus limitadas de tipo conservador. Material y métodos. Retrospectivamente analizamos los expedientes clínicos de pacientes con el diagnóstico de carcinoma epidermoide de la vulva tratados con disección ganglionar con incisión radical versus limitada, durante el periodo de enero de 1986 a diciembre de 1996, en el Instituto Nacional de Cancerología de México (INCan). Se seleccionaron nueve pacientes tratadas con vulvectomía o hemivulvectomía e incisión inguino-femoral limitada (Grupo I), uni o bilateral y 18 pacientes tratadas con vulvectomía o hemivulvectomía con incisiones separadas de la disección ganglionar inguino-femoral pero con incisión radical clásica (Grupo II). Resultados. Durante los 10 años de evaluación, 27 pacientes con carcinoma de vulva fueron identificadas. Para el grupo I el promedio de edad fue de 68.4 años versus 72.5 del grupo II (p= NS). El número de ganglios disecados y recurrencias locales no mostró diferencias con significancia estadística para ambos grupos. La supervivencia para las pacientes del grupo I fue del 66.7 por ciento y 42 por ciento para las del grupo II. Los únicos parámetros con p significativas fueron la frecuencia de bencrosis del colgajo (p= 0.03), infección de la herida quirúrgica (p= 0.05) a favor del grupo I (p= 0.07). Conclusiones. En nuestro Análisis la incisión limitada para realizar la disección ganglionar inguino-femoral ofrece menor morbilidad que la incisión radical clásica, sin repercusión en el control oncológico y supervivencia de las pacientes.

Teicoplanin pharmacokinetics in critically ill paediatric patients.

Twenty-one critically ill children aged between 7 days and 12 years were treated with teicoplanin (three loading dosages of 10 mg/kg at 12 h intervals, followed by a maintenance dosage of 10 mg/kg/day). Serum teicoplanin concentrations were monitored by HPLC. Mean concentrations in plasma 30 min after drug administration were 20 +/- 16.1 mg/L. The volume of distribution was 0.30 L/kg and the terminal half-life was 17.41 h. Only 11% of trough values were >10 mg/L (established as desirable values). In critically ill children a dosage of 10 mg/kg/day does not assure serum trough values >10 mg/L.

Sex-related differences in spatial learning during the early postnatal development of the rat.

Some authors have reported that male rats younger than 21 days old are unable to perform spatial learning correctly because they have still not developed the ability to use extra-maze cues. In experiment 1, we analyzed spatial learning in 14-, 21-, 30- and 42-day-old rats using the Morris water maze (MWM). According to our results, a good performance was observed in 30-day-old male rats whereas this was not observed in female rats until they were 42 days old. In experiment 2 we studied the role of sex hormones in this kind of learning using the MWM and 30-day-old rats (castrated male rats and female rats treated with testosterone propionate (TP) after birth). The latter group, the male control group and the castrated males all solved the task correctly. The objective of experiment 3 was to determine possible differences between the sexes in the use of taxon strategies in the T water maze. To summarize, sexual dimorphism was only observed in spatial learning during development.

Transpyloric enteral feeding in critically ill children.

BACKGROUND: Nutrition is important in childhood because the child has a lower energy reserve than the adult and a higher demand for calories because of ongoing growth. In this study, the utility of transpyloric enteral feeding (TEF) in critically ill children was evaluated. METHODS: A prospective, descriptive study was made in a pediatric intensive care unit of a tertiary pediatric center of 41 critically ill children, 30 after surgical procedures and 11 with nonsurgical illness, aged 8 days to 12 years, who received transpyloric enteral feeding with 8- or 10-Fr weighted feeding tubes. Analysis was made of tolerance and complications (vomiting, abdominal distension, excessive gastric residual, diarrhea, and pulmonary aspiration) of TEF. RESULTS: The mean duration of TEF was 19.5 +/- 26.8 days (range, 1-120 days). The administration of sedative agents or inotropic drugs did not alter toleration of TEF. Eight of 12 patients treated with continuous infusion of vecuronium tolerated TEF without complications. Eleven gastrointestinal complications occurred in 10 patients, abdominal distension and excessive gastric residual in 7 (17%), and diarrhea in 4 (9.7%). In 7 patients gastrointestinal complications improved, with decreasing use or transitory interruption of TEF, but in 4 patients (9.7%), TEF had to be withdrawn. Gastrointestinal complications were more frequent in postsurgical than in nonsurgical patients (p < 0.001). No patients suffered from pulmonary aspiration, and the incidence of pulmonary infection and hepatic dysfunction diminished during TEF. CONCLUSIONS: Transpyloric enteral feeding is a good method of nutritional support in critically ill children and can be used in patients treated with neuromuscular blocking agents. The frequency and severity of complications and the risks of pulmonary infection and hepatic dysfunction related to TEF are low.

Life-threatening effects of discontinuing inhaled nitric oxide in children.

We treated 40 children, aged between 15 d and 17 y, diagnosed with acute respiratory distress syndrome and/or pulmonary hypertension, with inhaled nitric oxide. The most frequent underlying diagnosis associated with ARDS were bronchopneumonia (eight), cardiac surgery (five), and sepsis (three). Pulmonary hypertension was secondary to cardiomyopathy in 2 patients and occurred in the postoperative period of cardiac surgery in 17 patients--the most frequent were ventricular septal defect (5), transposition of great arteries (4), and atrioventricular septal defect (3). In 11 patients, sudden discontinuation of nitric oxide induced a decrease in oxygenation associated in some of the patients with an increase in pulmonary artery pressure. In two patients discontinuation of nitric oxide induced severe pulmonary hypertension, extreme bradycardia and hypoxaemia, which required cardiopulmonary resuscitation. When exogenous nitric oxide is abruptly interrupted, hypoxaemia and pulmonary hypertension are found in some patients, due to a decrease in the nitric oxide concentration in the pulmonary circulation. This may be caused by the exogenous nitric oxide administration that may have inhibited endogenous production. We recommend making a progressive withdrawal of inhaled nitric oxide to avoid the side effects observed in the sudden discontinuation.

Influencia de la ingestión de grasas y la administración de estradiol en el desarrollo de carcinoma mamario inducido con DMBA en ratas / Influence of the ingestion of grease and the estradiol administration in the grow up in mamary carcinoma induce by DMBA in rats

Datos epidemiológicos sugieren que la dieta rica en grasas es un factor promotor en el desarrollo del cáncer mamario y puede esta relacionado con el estímulo estrogénico. El objetivo del presente estudio es demostrar la acción de la dieta grasa en carcinomas mamarios inducidos con 1,2-dimetilbenza(a)antraceno (DMBA) como agente promotor único o asociado con estímulo estrogénico. Se emplearon tres grupos experimentales: 1) Grupo con dieta grasa (DG) con 20 por ciento de aceite de maíz, 2) grupo con dieta normal (DN), ambos ad libitum; y 3) grupo con dieta subnormal (DSN)(10 g alimento diario). Todos con y sin estímulo estrogénico (1 *g diario de 17ß-estradiol). Al comparar los tres grupos se observó que 19 de los 21 (93 por ciento) animales con DG desarrollaron tumores mamarios, con una aparición temprana (novena semana y con el mayor tamaño (6 cm en promedio)(p=0.009). Los grupos DN Y DSN presentaron comportamiento tumoral menos agresivo, en el primer grupo la prevalencia fue de 61 por ciento con un tamaño tumoral de 5.5 cm; en el segundo la prevalencia fue de 41 por ciento, la latencia mucho mayor (aparición promedio a la semana 17) y tamaño tumoral menor (2 cm). Nuestros resultados indican que la dieta rica en grasas es un factor promotor importante e independiente del estímulo estrogénico. En general la estimulación hormonal no provocó cambios significativos en el comportamiento tumoral, aunque cabe destacar que el grupo DG con estímulo estrogénico presentó la mayor prevalencia en comparación con el resto de los grupos.