The role of microtopography and resident species in post-disturbance recovery of arid habitats in Hawai'i.

Habitat-suitability indices (HSI) have been employed in restoration to identify optimal sites for planting native species. Often, HSI are based on abiotic variables and do not include biotic interactions, even though similar abiotic conditions can favor both native and nonnative species. Biotic interactions such as competition may be especially important in invader-dominated habitats because invasive species often have fast growth rates and can exploit resources quickly. In this study, we test the utility of an HSI of microtopography derived from airborne LiDAR to predict post-disturbance recovery and native planting success in native shrub-dominated and nonnative, invasive grass-dominated dryland habitats in Hawai'i. The HSI uses high-resolution digital terrain models to classify sites' microtopography as high, medium, or low suitability, based on wind exposure and topographic position. We used a split-plot before-after-control-impact design to implement a disturbance experiment within native shrub (Dodonaea viscosa) and nonnative, invasive grass (Cenchrus clandestinus)-dominated ecosystems across three microtopography categories. In contrast to previous studies using the same HSI, we found that microtopography was a poor predictor of pre-disturbance conditions for soil nutrients, organic matter content, or foliar C:N, within both Dodonaea and Cenchrus vegetation types. In invader-dominated Cenchrus plots, microtopography helped predict cover, but not as expected (i.e., highest cover would be in high-suitability plots): D. viscosa had the greatest cover in low-suitability and C. clandestinus had the greatest cover in medium-suitability plots. Similarly, in native-dominated Dodonaea plots, microtopography was a poor predictor of D. viscosa, C. clandestinus, and total plant cover. Although we found some evidence that microtopography helped inform post-disturbance plant recovery of D. viscosa and total plant cover, vegetation type was a more important predictor. Important for considering the success of plantings, percent cover of D. viscosa decreased while percent cover of C. clandestinus increased within both vegetation types 20 months after disturbance. Our results are evidence that HSIs based on topographic features may prove most useful for choosing planting sites in harsh habitats or those already dominated by native species. In more productive habitats, competition from resident species may offset any benefits gained from "better" suitability sites.

[Jejunal gastrointestinal stromal tumor (GIST): clinical case]. / Tumor del estroma gastrointestinal (GIST) de yeyuno: caso clínico.

Background: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract. It is exposed a clinical case of jejunal GIST from a second-level hospital in Mexico. Clinical case: Female patient of 76 years, with history of tobacco use (two cigarettes per day for 25 years), that is referred to General Surgery due to a four month evolution of symptoms, characterized by abdominal pain, hyporexia and urinary symptomatology. Physical examination revealed a non-pulsatile, solid, non-mobile, non-painful mass in the hypogastrium and right iliac fossa of approximately 15 cm in length. Ovarian tumor was ruled out, since CEA and CA-125 tumor markers were negative. Abdominopelvic ultrasound was performed and reported a solid tumor with cystic spaces inside. CT reported a solid tumor of 9.5 x 2.5 x 8.3 cm, with defined edges, multilobed, presence of some calcifications in its wall that did not show enhancement with the use of contrast media. Patient underwent exploratory laparotomy and it was found a jejunal tumor, 210 cm from the ligament of Treitz. Immunohistochemistry reported positivity to KIT and DOG1, confirming the diagnosis of GIST. Conclusion: GISTs are uncommon entities. Their clinical presentation is insidious and the preoperative diagnosis is complex due to the need for biopsy. The treatment is surgery, but tyrosine kinase inhibitors should be administered. Even in patients with response to treatment, follow-up is mandatory due to the risk of recurrence.

Introducción: los tumores del estroma gastrointestinal (GIST) son los tumores mesenquimatosos más comunes del tracto gastrointestinal. Se expone un caso clínico de GIST en yeyuno que se presentó en un hospital de segundo nivel en México. Caso clínico: femenino de 76 años, con antecedente de tabaquismo (dos cigarros diarios durante 25 años), referida a Cirugía General por cuadro de cuatro meses de evolución (dolor abdominal tipo cólico en hipogastrio, hiporexia y sintomatología urinaria). A la exploración física, se le detectó tumor no pulsátil, sólido, no móvil, no doloroso, adherido a planos profundos en hipogastrio y fosa ilíaca derecha de aprox. 15 cm de longitud. Se descartó tumor ovárico al resultar negativos los marcadores tumorales ACE y CA-125. Se realizó ultrasonido abdominopélvico que reportó imagen de tumoración sólida con zonas quísticas en su interior. La TC reportó tumoración sólida, de bordes definidos, multilobulada con algunas calcificaciones milimétricas en su pared de 9.5 x 2.5 x 8.3 cm y sin realce al administrar medio de contraste. La paciente se sometió a laparotomía exploradora y se encontró tumoración adherida a yeyuno a 210 cm del ligamento de Treitz. El tumor fue positivo a KIT y DOG1, lo que confirmó el diagnóstico de GIST de patrón fusiforme. Conclusión: los GIST son poco frecuentes. Su presentación clínica es insidiosa y el diagnóstico preoperatorio es complejo debido a la toma de biopsia. El tratamiento continúa siendo la cirugía, pero se deben administrar inhibidores de la tirosina cinasa. Incluso en pacientes con respuesta favorable al tratamiento, se recomienda seguimiento por riesgo de recidiva.

Asociación entre el sistema IGF y PAPP-A en ateroesclerosis coronaria / Association between IGF system and PAPP-A in coronary atherosclerosis

Resumen La aterosclerosis es una enfermedad que involucra múltiples mecanismos fisiopatológicos cuyo conocimiento no se ha dilucidado por completo. Con frecuencia, los avances científicos sobre la fisiopatología aterogénica generan que a diversas moléculas no consideradas previamente en el panorama de dicha enfermedad se les atribuyan acciones sobre el inicio o progresión de la misma. Un ejemplo representativo es el estudio de un nuevo mecanismo involucrado en el proceso aterogénico, consistente en la asociación entre el sistema de factores de crecimiento similares a la insulina (IGF) y la proteína plasmática A asociada al embarazo (PAPP-A). El sistema IGF es una familia de péptidos compuesto por 3 hormonas peptídicas, 4 receptores transmembranales y 6 proteínas transportadoras. El factor de crecimiento similar a la insulina tipo 1 (IGF-1) es el principal ligando del sistema IGF involucrado en la aterosclerosis coronaria y ejerce sus efectos mediante la activación del receptor IGF-1R en células de músculo liso vascular de las arterias coronarias o en macrófagos de placas ateroscleróticas. En células de músculo liso vascular promueve la migración y previene la apoptosis aumentando la estabilidad de la placa, y en macrófagos disminuye el transporte reverso de colesterol propiciando la formación de células espumosas. La regulación de la biodisponibilidad de IGF-1 en el endotelio se lleva a cabo por las proteasas de proteínas IGFBP, principalmente por la PAPP-A. En la presente revisión se abordan los mecanismos involucrados entre el sistema IGF y la PAPP-A en aterosclerosis coronaria con énfasis en los efectos moleculares producidos en células de músculo liso vascular y en macrófagos.

Abstract Atherosclerosis is a condition that involves multiple pathophysiological mechanisms and whose knowledge has not been fully elucidated. Often, scientific advances on the atherogenic pathophysiology generate that molecules not previously considered in the scene of this disease, were attributed actions on the onset or progression of it. A representative example is the study of a new mechanism involved in the atherogenic process, consisting of the association between the insulin-like growth factor (IGF) system and pregnancy-associated plasma protein-A (PAPP-A). Insulin-like growth factor system is a family of peptides that include 3 peptide hormones, 4 transmembrane receptors and 6 binding proteins. Insulin-like growth factor-1 (IGF-1) is the main ligand of the IGF system involved in coronary atherosclerosis. IGF-1 exerts its effects via activation of the IGF-1R receptor on vascular smooth muscle cells or macrophages. In vascular smooth muscle cells promotes migration and prevents apoptosis which increases plaque stability while in macrophages reduces reverse cholesterol transport leading to the formation of foam cells. Regulation of IGF-1 endothelial bioavailability is carried out by IGFBP proteases, mainly by PAPP-A. In this review, we address the mechanisms between IGF system and PAPP-A in atherosclerosis with emphasis on molecular effects on vascular smooth muscle cells and macrophages.

[Association between IGF system and PAPP-A in coronary atherosclerosis]. / Asociación entre el sistema IGF y PAPP-A en ateroesclerosis coronaria.

Atherosclerosis is a condition that involves multiple pathophysiological mechanisms and whose knowledge has not been fully elucidated. Often, scientific advances on the atherogenic pathophysiology generate that molecules not previously considered in the scene of this disease, were attributed actions on the onset or progression of it. A representative example is the study of a new mechanism involved in the atherogenic process, consisting of the association between the insulin-like growth factor (IGF) system and pregnancy-associated plasma protein-A (PAPP-A). Insulin-like growth factor system is a family of peptides that include 3 peptide hormones, 4 transmembrane receptors and 6 binding proteins. Insulin-like growth factor-1 (IGF-1) is the main ligand of the IGF system involved in coronary atherosclerosis. IGF-1 exerts its effects via activation of the IGF-1R receptor on vascular smooth muscle cells or macrophages. In vascular smooth muscle cells promotes migration and prevents apoptosis which increases plaque stability while in macrophages reduces reverse cholesterol transport leading to the formation of foam cells. Regulation of IGF-1 endothelial bioavailability is carried out by IGFBP proteases, mainly by PAPP-A. In this review, we address the mechanisms between IGF system and PAPP-A in atherosclerosis with emphasis on molecular effects on vascular smooth muscle cells and macrophages.