Abordaje posterior como tratamiento del ganglioneuroma retrorrectal, un tumor infrecuente / Posterior approach as treatment of retrorrectal ganglioneuroma, a rare tumor

Los ganglioneuromas son tumores benignos del sistema nervioso simpático, con origen en las células de la cresta neural. Forman parte del grupo de tumores neurogénicos, segundo en frecuencia en la clasificación de tumores retrorrectales. Describimos el caso de una mujer de 71 años que presenta una lesión en el espacio retrorrectal izquierdo de unos 45 X 21 X 56mm con una biopsia guiada por TC preoperatoria que descarta malignidad. Se decide exéresis de la tumoración a través de un abordaje posterior, realizando una incisión parasacrococcígea izquierda. El estudio anatomopatológico de la pieza quirúrgica describe un ganglioneuroma con bordes de resección libres. Los tumores de localización retrorrectal son infrecuentes y a pesar de no ser sintomáticos, se recomienda su exéresis. Por tanto, un correcto estudio preoperatorio para una estrategia quirúrgica adecuada es esencial. La RMN es el método diagnóstico de elección y fundamental para elegir el abordaje quirúrgico. De manera general, lesiones con límite superior por encima de S3 o con invasión locorregional de estructuras pelvianas, requerirían un aborde abdominal o en ocasiones combinado. Por tanto, una amplia exéresis del tumor es el pilar fundamental del tratamiento. La recurrencia postoperatoria y la trasformación maligna, aunque están descritas en la literatura hasta la fecha, son extraordinarias

Ganglioneuromas are benign lesions arising from sympathetic ganglion cells. They are in the neurogenic group, second in frequency in retrorectal tumors clasification. We present a case of a 71-year-old woman who presented a lesion in the left retrorectal space around 45 X 21 X 56 mm with a preoperative CT-guided biopsy that ruled out malignancy. The tumor was excised through a posterior approach, using a left parasacrococcygeal incision. Postoperative histopathologic study confirmed the lesion as a ganglioneuroma. Retrorectal tumors are uncommon and may be incidental, but their excision is recommended. Therefore, a correct preoperative study is essential. Pelvic MRI is the best imaging modality and aids surgical planning. In general, lesions with an upper limit above S3 or with locoregional invasion of pelvic structures would require an abdominal or combined approach. Therefore, a complete excision of the tumor is the mainstay of the treatment. Postoperative recurrence and malignant transformation, although described in the literature, are extraordinary

Escisión Mesorrectal Total Transanal (Tatme): Aspectos Prácticos De La Técnica Quirúrgica / Transanal Total Mesorectal Excision: Practical Aspects Of Surgical Technique

INTRODUCCIÓN: El cáncer de recto es la séptima neoplasia más frecuente en España con una incidencia de 12570 casos/100.000 hab/año. La supervivencia a 5 años en Europa es del 55-62 % y tiende a aumentar gracias a la introducción de cambios en el tratamiento y nuevas técnicas quirúrgicas. La TaTME permite visualizar directamente el margen distal del tumor, evita las dificultades técnicas que aparecen al introducir las endograpadoras lineales en pelvis estrechas para seccionar el recto y ofrece una visualización directa de las estructuras pélvicas durante la EMT. El objetivo de este estudio es describir la técnica quirúrgica de la TaTME minuciosamente destacando los aspectos más prácticos del procedimiento. MATERIAL Y MÉTODOS: Se ha realizado una búsqueda bibliográfica sistemática en la base de datos Cochrane, MEDLINE y EMBASE mediante los términos "transanal total mesorectal excision". RESULTADOS: Durante la fase transanal se coloca el dispositivo gel-point monopuerto y multicanal transanal para la creación del neumorrecto. La luz del recto se cierra mediante una sutura en bolsa de tabaco. Tras completar la rectotomía se procede a la escisión mesorrectal total. Para la fase abdominal se crea un neumoperitoneo. Los vasos mesentéricos inferiores se seccionan en origen. Una vez que ambos equipos han avanzado en la escisión mesorrectal los campos se comunican abriendo el por el plano anterior. Se pueden construir varios tipos de anastomosis colorrectales. CONCLUSIÓN: La TaTME es un tratamiento quirúrgico del cáncer de recto medio y bajo seguro y factible

INTRODUCTION: Rectal cancer is the seventh most common cancer in Spain with an incidence of 12570 cases/100000 h/year. The 5-year overall survival of rectal cancer in Europe was 55-62% and this rate tends to improve due to new challenges and the development of new surgical techniques. TaTME offers a direct vision of the distal end of tumour, it avoids technical difficulties for in-troducing staplers down a narrow pelvis and it improves a direct visualization of pelvic structures during total mesorectal excision. The aim of this study is to describe the surgical technique for TaTME selecting the most practical aspects of this procedure. MATERIAL AND METHODS: The relevant studies were identified by a search of MEDLINE, EMBASE and Cochrane Oral Health Group Specialized Register using terms transanal total mesorectal excision. RESULTS: During transanal phase pneumorectum is created using Gel Point Path Transanal Access platform. The rectal lumen is closed with a purse.string suture. After a complete rectotomy the total mesorectal excision is performed circumferentially. Pneu-moperitoenum is created for abdominal phase. When transanal and abdominal teams have achieved a complete total mesorectal excision both planes are connected at the anterior plane. Several types of colorectal anastomosis can be performed. CONCLUSIÓN: TaTME is a secure and feasible surgical treatment for low-mid rectal cancer

Medicina basada en la evidencia y la cirugía del cáncer de recto / Evidence based medicine and surgery for rectal cancer

Introducción: El cáncer colorrectal es la cuarta neoplasia más frecuente en el mundo. La supervivencia del cáncer de recto tiende a aumentar debido a las actualizaciones en las estrategias terapéuticas basadas en recomendaciones que siguen las pautas de la medicina basada en la evidencia. El objetivo de este artículo es realizar una revisión sobre la evidencia científica publicada en relación a la cirugía del cáncer de recto. Material y Métodos: Se ha realizado una búsqueda bibliográfica sistemática en la base de datos Cochrane, MEDLINE y EMBASE mediante los términos "rectal cancer AND surgical treatment AND evidence based medicine". Resultados: El tratamiento del cáncer de recto requiere de un equipo multidisciplinar que considere guías clínicas elaboradas por las sociedades médicas. Se recomienda la resección quirúrgica en bloque del recto y de los tejidos invadidos por tumor junto con la obtención de márgenes de resección libres (distal y circunferencial) y la escisión completa del mesorrecto. El lavado y las pruebas de estanqueidad de la anastomosis intraoperatorios mejoran los resultados de la cirugía. La cirugía laparoscópica del cáncer de recto realizada por cirujanos expertos mejora la recuperación postoperatoria con los mismos resultados oncológicos. Conclusión: La medicina basada en la evidencia proporciona unas recomendaciones para el tratamiento quirúrgico del cáncer de recto con el fin de lograr los mejores resultados

Introduction: Colorectal cancer is the fourth most common malignant in the world. The improvement in the 5-year survival for rectal cancer is probably related to multidimensional management included in clinical practice guidelines based on the scientific evidence. This systematic review was to evaluate the recommendations about surgery for rectal cancer. Materials and Methods: The relevant studies were identified by a search of MEDLINE, EMBASE and Cochrane Oral Health Group Specialized Register using terms rectal cancer AND surgical treatment AND evidence based medicine. Results: Management of rectal cancer requires a coordinated multidisciplinary team that applies the recommendations included in clinical practice guidelines. Surgical resection for rectal cancer follow the main oncologic principles as resection on bloc for locally advanced rectal tumors, adequate distal and circumferential margins and complete mesorectal excision. Intraluminal rectal washout and anastomotic leak testing were recommended. Laparoscopic approach by expert surgeons improves immediate postoperative outcomes and is as safe as the open approach in terms of oncological results. Conclusion: Adherence to evidence-based medicine included in surgical guidelines and personalization improves outcomes in rectal cancer surgery

Substance P receptor antagonist reverses intestinal pathophysiological alterations occurring in a novel ex-vivo model of Cryptosporidium parvum infection of intestinal tissues derived from SIV-infected macaques.

BACKGROUND: Cryptosporidium infection leads to life-threatening diarrhea in AIDS patients. Pathogenesis of cryptosporidiosis is due to intestinal physiological alterations. We devised an ex-vivo model using ex-vivo Cryptosporidium parvum infection of jejunal tissues derived from SIV-infected macaques and studied the role of substance P (SP) in the pathogenesis of cryptosporidiosis. METHODS: We measured jejunal SP protein levels using ELISA, and electrophysiological alterations using the Ussing chamber technique in an ex vivo model of Cryptosporidium infection. Paraformaldehyde-fixed jejunum from SIV-infected macaques with and without naturally occurring cryptosporidiosis was studied for SP protein expression by immunohistochemistry and fluorescence deconvolution microscopy. RESULTS: Ex-vivo Cryptosporidium-infected tissues and tissues from SIV-infected macaques with naturally occurring cryptosporidiosis demonstrated elevated SP protein levels compared with tissues from SIV-infected animals without ex-vivo C. parvum infection or tissues from SIV-infected animals that have no evidence of cryptosporidiosis. In our ex-vivo model of Cryptosporidium infection, we demonstrated pathophysiological alterations that were blocked by SP-receptor antagonist treatment. CONCLUSIONS: These studies suggest that SP-receptor antagonists could prove useful for treatment of AIDS-related cryptosporidiosis.

Immunoglobulin-A nephropathy with crescentic glomerulonephritis in a pigtailed macaque (Macaca nemestrina).

A 4-year-old female pigtailed macaque (Macaca nemestrina), experimentally coinfected with simian immunodeficiency virus (SIVmac251) and Mycobacterium bovis(bacillus Calmette-Guerin), was euthanatized 1 year after infection because of weight loss and labored breathing. On gross examination, both kidneys were found to be markedly enlarged (right: 54.7 g and left: 51.7 g; normal < 20 g). Renal lesions were evaluated by histopathologic, immunohistochemical, and ultrastructural methods. Light microscopy revealed that the glomeruli were diffusely hypercellular with expansion of the mesangial matrix, and crescent formation affected approximately 60% of the glomeruli. By immunohistochemical evaluation, it was found that the crescents were composed principally of macrophages, as seen by CD68 (KP1), MRP8, MAC387, and HAM56 expression. Electron microscopic examination of the glomeruli revealed extensive intramembranous, subendothelial, and mesangial electron-dense deposits and multifocal fusion of the visceral epithelial foot processes. Immunofluorescence, used to determine the composition of the electron-dense deposits, revealed diffuse granular mesangial and capillary staining for immunoglobulin A (IgA). The renal changes described in this case report are most consistent with the findings of crescentic gloerulonephritis with IgA immune complex deposition in the glomerular basement membrane and mesangium as described in humans with IgA nephropathy.

Effects of high molybdenum intake on 1.2 - dimethylhydrazine-induced intestinal tumors in rats

Wistar male rats, 3 months of age were given ad-libitum a nutritionally adequate diet and demineralized drinking water. The Molybdenum (Mo) and Tungsten (W) were provided in the drinking water at 200 ppm concentration. Intestinal tumors were induced by 1,2-dimethylhydrazine (DMH) given subcutaneously as 16 weekly doses at 20 mg/kg body weight. Mo in the form of (NH4)6 Mo7O24 4H2O or W in the form of (Na2WO4) were provided in the drinking water two months before the first DMH treatment and were continued during 4 months more until the last DMH treatment. Three months after the last carcinogen injection, all animals were sacrificed and examined for intestinal tumors. The number, size and location of the tumors were recorded and the pathology was examined. The addition of Mo to the drinking water induced an increase of hepatic Mo content. At the end of the second month, the hepatic content of Mo was 5.61 ppm, compared with control and W groups (2.18 and 0.96 ppm, respectively). A significantly lower incidence of tumors was observed in the Mo group (47), compared with the control group given DMH alone (105) and W group (113). On the other hand, the Mo group showed a significant decrease in the numbers of multiple tumors per rat.

Effects of high molybdenum intake on 1.2 - dimethylhydrazine-induced intestinal tumors in rats

Wistar male rats, 3 months of age were given ad-libitum a nutritionally adequate diet and demineralized drinking water. The Molybdenum (Mo) and Tungsten (W) were provided in the drinking water at 200 ppm concentration. Intestinal tumors were induced by 1,2-dimethylhydrazine (DMH) given subcutaneously as 16 weekly doses at 20 mg/kg body weight. Mo in the form of (NH4)6 Mo7O24 4H2O or W in the form of (Na2WO4) were provided in the drinking water two months before the first DMH treatment and were continued during 4 months more until the last DMH treatment. Three months after the last carcinogen injection, all animals were sacrificed and examined for intestinal tumors. The number, size and location of the tumors were recorded and the pathology was examined. The addition of Mo to the drinking water induced an increase of hepatic Mo content. At the end of the second month, the hepatic content of Mo was 5.61 ppm, compared with control and W groups (2.18 and 0.96 ppm, respectively). A significantly lower incidence of tumors was observed in the Mo group (47), compared with the control group given DMH alone (105) and W group (113). On the other hand, the Mo group showed a significant decrease in the numbers of multiple tumors per rat. (AU)

Effects of high molybdenum intake on 1,2-dimethylhydrazine-induced intestinal tumors in rats.

Wistar male rats, 3 months of age were given ad-libitum a nutritionally adequate diet and demineralized drinking water. The Molybdenum (Mo) and Tungsten (W) were provided in the drinking water at 200 ppm concentration. Intestinal tumors were induced by 1,2-dimethylhydrazine (DMH) given subcutaneously as 16 weekly doses at 20 mg/kg body weight. Mo in the form of (NH4)6 Mo7O24 4H2O or W in the form of (Na2WO4) were provided in the drinking water two months before the first DMH treatment and were continued during 4 months more until the last DMH treatment. Three months after the last carcinogen injection, all animals were sacrificed and examined for intestinal tumors. The number, size and location of the tumors were recorded and the pathology was examined. The addition of Mo to the drinking water induced an increase of hepatic Mo content. At the end of the second month, the hepatic content of Mo was 5.61 ppm, compared with control and W groups (2.18 and 0.96 ppm, respectively). A significantly lower incidence of tumors was observed in the Mo group (47), compared with the control group given DMH alone (105) and W group (113). On the other hand, the Mo group showed a significant decrease in the numbers of multiple tumors per rat.

Effects of high molybdenum intake on 1,2-dimethylhydrazine-induced intestinal tumors in rats.

Wistar male rats, 3 months of age were given ad-libitum a nutritionally adequate diet and demineralized drinking water. The Molybdenum (Mo) and Tungsten (W) were provided in the drinking water at 200 ppm concentration. Intestinal tumors were induced by 1,2-dimethylhydrazine (DMH) given subcutaneously as 16 weekly doses at 20 mg/kg body weight. Mo in the form of (NH4)6 Mo7O24 4H2O or W in the form of (Na2WO4) were provided in the drinking water two months before the first DMH treatment and were continued during 4 months more until the last DMH treatment. Three months after the last carcinogen injection, all animals were sacrificed and examined for intestinal tumors. The number, size and location of the tumors were recorded and the pathology was examined. The addition of Mo to the drinking water induced an increase of hepatic Mo content. At the end of the second month, the hepatic content of Mo was 5.61 ppm, compared with control and W groups (2.18 and 0.96 ppm, respectively). A significantly lower incidence of tumors was observed in the Mo group (47), compared with the control group given DMH alone (105) and W group (113). On the other hand, the Mo group showed a significant decrease in the numbers of multiple tumors per rat.

Histopathological characterization of nephritides in the brown capuchin monkey, Cebus apella (Primates: Cebidae).

The renal lesions are of special importance in the captive primates. The most commonly pathologies are: pyelonephritis, nephrocalcinosis, glomerulonephritis, congenital malformations, hydronephrosis and functional diseases. We report the histopathological study of renal lesions of five cases of deaths in Cebus apella (Primates) of the Argentinean Primate Center. The ages of the monkeys were from 4 months to 15 years old. Microscopically, we have observed principally acute diffuse proliferative glomerulonephritis, hilar mesangio proliferative glomerulonephritis, extracapilar glomerulonephritis with crescents, chronic interstitial nephritis and chronic pyelophritis.

Glomerular lesions in renal biopsies of Saimiri boliviensis (primate) examined by light and electron microscopy and immunohistochemistry.

In order to determine the existence of glomerular lesions in Saimiri boliviensis, renal biopsies were performed in 20 clinically healthy animals of similar age and both sexes. Biopsies were obtained by laparotomy with a Tru-Cut biopsy needle. Mesangioproliferative glomerulonephritis characterized by an increased number of mesangial cells and increased mesangial matrix was present in 35% of the animals. Proliferative glomerulonephritis characterized by increased numbers of epithelial and endothelial cells with narrowed capillary lumen, and membranous glomerulonephritis characterized by diffuse thickening, wrinkling, and occasional lamellation of basement membranes, were present in 15% of the samples. Ultrastructural features included increased mesangial matrix, fusion of the visceral epithelial foot processes, thickened glomerular basement membranes, and incipient lamellation. Immunohistochemical examination revealed granular deposits of immunoglobulin M in the cytoplasm of mesangial cells and in the mesangial matrix in 50% of the samples.

Failure to induce tumors in the large intestine of Capuchin mokeys (Cebus apella) by using 1,2-dimethylhydrazine.

The purpose of this study was to produce tumors in the large intestine of Capuchin Monkeys (Cebus apella) by the administration of the colonotropic carcinogen 1,2-dimethylhydrazine (DMH). The subjects were 12 monkeys, all males, age 30 months, with a mean weight of 2.858 kg. The DMH was administered subcutaneously to six of the monkeys at a dosage of 25 mg/kg of body weight once a week for 16 weeks; control monkeys received an equivalent volume of the stock solution without DMH. Twenty months after administration of the first dose, the animals were sacrificed. None of the monkeys showed intestinal tumors. Samples of the gastrointestinal tract were removed, fixed, and stained according to standard histological techniques. Histological changes were seen in all of the DMH-treated animals; these consisted of glandular hyperplasia and hyperplasia of the epithelium overlying the lymphoid nodules. In addition, foci of dysplasia were found in three of the animals. Our results suggest that the DMH induced pre-neoplastic changes, characterized by hyperplasia and dysplasia, in the mucosa of the large intestine.

[Description of the external morphology of Duboisiella proloba Baer, 1983 (Trematoda: Strigeida) from Didelphis albiventris in argentina, by scanning electronic microscope]. / Descripción de la morfología externa de Duboisiella proloba Baer, 1938 (Trematoda: Strigeida) de Didelphis albiventris en Argentina, por microscopía electrónica de barrido.

The aim of this study was to report some external morphological features of Duboisiella proloba Baer, 1938. The parasites were collected during necropsy from the small intestine of Didelphis albiventris hunted in its native environment near Corrientes City, Argentina. Collected specimens of Duboisiella proloba were observed by light microscopy in order to be classified. Later the parasites were put into a 3% glutaraldehyde solution, dehydrated, dried by critical point, assembled, metallized, observed and photographed with a SEM. This is the first description of some external morphologic features of this species carried out by SEM in Argentina.

[Histological and histochemical study of hyperplastic and dysplastic lesions of the large intestine in Cebus Apella (primate) treated with 1,2-dimethylhydrazine]. / Estudio histológico e histoquímico de lesiones hiperplásicas y displásicas del intestino grueso en Cebus apella (primate) tratado con 1,2-dimetilhidrazina.

The main objective of this study was to assess the histological changes of colon ephitelium in Cebus apella induced by 1,2-dimethylhydrazine (DMH) administration. Twelve monkeys, males, (aged x: 30 months) with an average body weight of 2,800 g were utilized. The DMH was injected subcutaneously at 25 mg/kg and continued once a week for 16 weeks. The body weight was assessed once a week during the first 4 months and every 30 days until the end of the experience. Histological changes of intestinal ephitelium and mucins were assessed at the end of the experience in specimens sectioned at 5 microns, stained with Haematoxylin and Eosin, PAS and Alcian blue pH 2.5. The histological and histochemical study permitted to characterize the normal morphology, as well as the mucins characteristics in the three regions: caecum, transverse colon and distal colon. The histological changes in the DMH treated animals were hyperplasia, dysplasia and mucins decreasing. The hyperplastic changes were localizated in glandular crypts, and in the epithelio located over the lymphoid nodules. The dysplastic crypts were observed in the transverse colon and in the last portion of distal colon. These lesions were located in the upper portion as well as the bottom of the mucosa. A decrease of neutral and acids mucopolysaccharides were observed in the crypts. The results of this study suggest that the DMH induced hyperplastic changes in the crypts and in the epithelium located over the lymphoid nodules and dysplastic focus, as well as a decrease of neutral and acids mucopolysaccharides.

[Trichophyton simii in a "Caí" monkey (Cebus apella) colony in the province of Corrientes, Argentina.]. / Trichophyton simii en una colonia de monos "Caí" (Cebus apella), en la provincia de Corrientes, Argentina.

The objective is to describe an outbreak of Trichophyton simii in a Cebus apella monkey colony in Argentine. During summer, alopecic zones appeared on dorsal regions from head to base of the tail of the animals. The hair and skin of nine animals were streaked onto Sabouraud dextrose with cloramphenicol and incubated at 25 degrees C. By the 10th day, white, filamentous colonies, which turned pale pink, developed from simples of four animals. Microscopical examinations were carried out and, because of colony and macroconidia morphology, were classified as Trichopyton simii. Although infection with T. simii is considered a zoonosis, we did not find human cases.

Estudio histológico e histoquímico de lesiones hiperplásicas y displásicas del intestino grueso en Cebus Apella (primate) tratado con 1, 2-dimetilhidrazida / Histological and histochemical study of hyperplastic and dysplastic lesions of the large intestine in Cebus Apella (primate) treated with 1, 2-dimethylhydrazine

El principal objetivo del presente trabajo consistió en determinar los cambios histológicos en el epitelio del colon en primates de la especie Cebus apella inducidos mediante la administración de la 1,2-dimetilhidrazina (DMH). Fueron utilizados 12 primates, machos de 30 meses de edad y con un peso promedio de 2,800Kg. La DMH fue administrada por vía subcutánea a razón de 25 mg/Kg de peso corporal semanalmente, durante 16 semanas. Durante los 20 meses que duró la experiencia el peso corporal fue evaluado semanalmente en los primeros 4 meses y cada 30 días hasta el final del experimento. Al final de la experiencia, en cortes histológicos de 5 mum, coloreados con Hematoxilina-Eosina, fueron evaluados los cambios histológicos del epitelio intestinal, así como las mucosustancias, utilizándose las técnicas del PAS y Alcian blue e pH 2,5. El estudio histológico e histoquímico permitió caracterizar la morfología normal, así como las características de las mucosustancias en tres regiones: ciego, colon transverso y colon distal. Los cambios histológicos observados en los animales tratados con DMH consistieron en fenómenos de hiperplasia, displasia y disminución de las mucosustancias. Los cambios hiperplásicos comprometieron a las criptas glandulares y al epitelio superficial que reviste a los nódulos linfoides. Focos de displasia fueron observados en el colon transverso y última porción del colon distal y comprometieron a criptas localizadas tanto en profundidad como en criptas de la mucosa superficial. Se observaron criptas con disminución de mucosustancias neutras y ácidas. Nuestros resultados sugieren que la DMH indujo en el colon, focos displásicos y lesiones hiperplásicas en criptas y en el epitelio que reviste a los nódulos linfoides, así como disminución de las mucosustancias neutras y ácidas.

Estudio histológico e histoquímico de lesiones hiperplásicas y displásicas del intestino grueso en Cebus Apella (primate) tratado con 1, 2-dimetilhidrazida / Histological and histochemical study of hyperplastic and dysplastic lesions of the large intestine in Cebus Apella (primate) treated with 1, 2-dimethylhydrazine

El principal objetivo del presente trabajo consistió en determinar los cambios histológicos en el epitelio del colon en primates de la especie Cebus apella inducidos mediante la administración de la 1,2-dimetilhidrazina (DMH). Fueron utilizados 12 primates, machos de 30 meses de edad y con un peso promedio de 2,800Kg. La DMH fue administrada por vía subcutánea a razón de 25 mg/Kg de peso corporal semanalmente, durante 16 semanas. Durante los 20 meses que duró la experiencia el peso corporal fue evaluado semanalmente en los primeros 4 meses y cada 30 días hasta el final del experimento. Al final de la experiencia, en cortes histológicos de 5 mum, coloreados con Hematoxilina-Eosina, fueron evaluados los cambios histológicos del epitelio intestinal, así como las mucosustancias, utilizándose las técnicas del PAS y Alcian blue e pH 2,5. El estudio histológico e histoquímico permitió caracterizar la morfología normal, así como las características de las mucosustancias en tres regiones: ciego, colon transverso y colon distal. Los cambios histológicos observados en los animales tratados con DMH consistieron en fenómenos de hiperplasia, displasia y disminución de las mucosustancias. Los cambios hiperplásicos comprometieron a las criptas glandulares y al epitelio superficial que reviste a los nódulos linfoides. Focos de displasia fueron observados en el colon transverso y última porción del colon distal y comprometieron a criptas localizadas tanto en profundidad como en criptas de la mucosa superficial. Se observaron criptas con disminución de mucosustancias neutras y ácidas. Nuestros resultados sugieren que la DMH indujo en el colon, focos displásicos y lesiones hiperplásicas en criptas y en el epitelio que reviste a los nódulos linfoides, así como disminución de las mucosustancias neutras y ácidas. (AU)

Spontaneous hepatocellular carcinoma in Saimiri boliviensis.

Hepatocellular carcinomas are rare in nonhuman primates. In this study we found the first naturally occurring hepatocellular carcinoma in a Squirrel Monkey (Saimiri boliviensis) of at least 24 years of age. In the necropsy, the liver was cirrhotic and contained multiple tumorous nodules, which varied in diameter from 3 to 15 mm. The lungs also contained small neoplastic masses. In the histological study, samples of liver, lungs, and other organs were taken and fixed in 10% buffered formalin, embedded in paraffin, cut at 5 microns, and colored with hematoxylin and eosin. The histological study of the liver permitted the detection of multiple masses of neoplastic liver cells in a closely packed trabecular configuration surrounded by a well-developed capillary basement membrane. Cirrhotic changes also were observed in the liver. The histological study of the lung confirmed the metastasis of the hepatocellular carcinoma. Metastasis was not found in other organs.

Aortic aneurysm in a Cebus apella monkey with experimentally induced atherosclerosis.

The sudden death of a Cebus apella female (> 19 years old) on an experimental hyperlipidic diet during three years is described. The gross lesions were hemothorax, atherosclerotic plaques in the aortic curve, and an aneurysm in the ascending aorta. Histologically, an enlargement of the intima in the ascending aorta with hyalinization and a thrombus were observed. The media was thinned and showed sclerosis and hemorrhage extending to the tunica adventicia.