Cardiac and lung endothelial cells in response to fluid shear stress on physiological matrix stiffness and composition.

OBJECTIVE: Preconditioning of endothelial cells from different vascular beds has potential value for re-endothelialization and implantation of engineered tissues. Understanding how substrate stiffness and composition affects tissue-specific cell response to shear stress will aid in successful endothelialization of engineered tissues. We developed a platform to test biomechanical and biochemical stimuli. METHODS: A novel polydimethylsiloxane-based parallel plate flow chamber enabled application of laminar fluid shear stress of 2 dynes/cm2 for 12 hours to microvascular cardiac and lung endothelial cells cultured on cardiac and lung-derived extracellular matrix. Optical imaging of cells was used to quantify cell changes in cell alignment. Analysis of integrin expression was performed using flow cytometry. RESULTS: Application of fluid shear stress caused the greatest cell alignment in cardiac endothelial cells seeded on polystyrene and lung endothelial cells on polydimethylsiloxane. This resulted in elongation of the lung endothelial cells. αv and ß3 integrin expression decreased after application of shear stress in both cell types. CONCLUSION: Substrate stiffness plays an important role in regulating tissue-specific endothelial response to shear stress, which may be due to differences in their native microenvironments. Furthermore, cardiac and lung endothelial cell response to shear stress was significantly regulated by the type of coating used.

Laminar shear stress modulates endothelial luminal surface stiffness in a tissue-specific manner.

OBJECTIVE: Endothelial cells form vascular beds in all organs and are exposed to a range of mechanical forces that regulate cellular phenotype. We sought to determine the role of endothelial luminal surface stiffness in tissue-specific mechanotransduction of laminar shear stress in microvascular mouse cells and the role of arachidonic acid in mediating this response. METHODS: Microvascular mouse endothelial cells were subjected to laminar shear stress at 4 dynes/cm2 for 12 hours in parallel plate flow chambers that enabled real-time optical microscopy and atomic force microscopy measurements of cell stiffness. RESULTS: Lung endothelial cells aligned parallel to flow, while cardiac endothelial cells did not. This rapid alignment was accompanied by increased cell stiffness. The addition of arachidonic acid to cardiac endothelial cells increased alignment and stiffness in response to shear stress. Inhibition of arachidonic acid in lung endothelial cells and embryonic stem cell-derived endothelial cells prevented cellular alignment and decreased cell stiffness. CONCLUSIONS: Our findings suggest that increased endothelial luminal surface stiffness in microvascular cells may facilitate mechanotransduction and alignment in response to laminar shear stress. Furthermore, the arachidonic acid pathway may mediate this tissue-specific process. An improved understanding of this response will aid in the treatment of organ-specific vascular disease.

Uso del misoprostol para inducción del parto en mujeres embarazadas en el tercer trimestre, en el servicio de aro II en el del Hospital Escuela Oscar Danilo Rosales Arguello (HEODRA) marzo 2005- noviembre 2007 / I use of the misoprostol for induction of the childbirth in women embarrassed in the third trimester, in the service of hoop II in that of the Hospital School Oscar Danilo Rosales Arguello (HEODRA) March 2005 - November 2007

Es un estudio de tipo descriptivo de serie de casos realizado en el departamento de gineco-obstetricia del HEODRA en la sala de labor y parto durante el año 2005-2007. La población del estudio fueron todas las pacientes con indicación de interrupción del embarazo sin contraindicación de parto vaginal y que se encontraban hospitalizadas en la Sala de ARO II a las cuales por indicación médica se le aplicó misoprostol determinando para ello el índice de Bishop y que estén confinadas en el expediente clínico. En relación a las dosis utilizada encontramos que en su mayoría fue de 50 ug y solo en 7 pacientes se uso dosis de 25 ug y que al compararla con el índice de bishop (usado para valorar el estado cervical) y el número de dosis se observó que ambas dosis el comportamiento es el mismo. Del total de pacientes inducidas con misoprostol solo un 13 porciento de las mismas terminaron en parto por vía césarea (19 pacientes) demostrándose que la mayoría de pacientes terminaron por vía vaginal. Para el seguimiento el parto el utilizo el partograma y de acuerdo a la clasifcación del mismo se obervó que un 53.1 porciento se desarrolló y terminó de manera adecuada, un 12.9 porciento no aplicó por terminar vía cesárea, y un 30.6 porciento el parto se desarrollo de manera precipitada. Se presentaron complicaciones en 21 pacientes predominanado hipertonía 6 (4.1 porciento), taquisistolia &(4.1 porciento) SFA 5 (3.4 porciento; y las consideras mas severas una pro cada una rotura uterina, muerte fetal, hemorragia posparto. Se presentó una complicación en 7 pacientes que utilizó la dosis de 25 ug. Este estudio nos demuestra que el misoprostol es mas efectivo cuando el índice de Bishop fue mayor de cuatro y en aquellas en donde la paridad era mayor. Sin embargo hay que considerar que el mayor número de pacientes en las que se utilizó eran primigestas y aun así resulto eficaz para inducción...