Browsing by Author "Angunawela, P."

Now showing 1 - 4 of 4

Histological and ultra-structural changes in enpothelial cells of the placenta in hypertensive disorders of pregnancy
(Sri Lanka Medical Association, 2000) Salgado, L.S.S.; Angunawela, P.; Tissera, A.; Sirisena, J.
INTRODUCTION: The maternal syndrome of pre-eclampsia is thought to result from a generalized vascular endothelial cell disturbance caused by a circulating factor probably derived from the placenta. Objective: Study the histological and ultra-structural changes of endothelial cells, so that the contribution of these changes to the pathogenesis of hypertensive disorders of pregnancy can be understood. METHOD: Placentae of 150 normal pregnancies and 200 hypertensive disorders of pregnancy were selected for this study. Tissue from the fetal surface was obtained for microscopic examination. Electron microscopic examination was done on 20 normal placentae and 30 placentae from hypertensive disorders of pregnancy. RESULTS: Histologically there were no significant changes in the normal group and in the group with hypertensive disorders of pregnancy. Ultra-structurally significant changes were observed in golgi bodies, mitochondria, pinocytotic vesicles, rough endoplasmic reticulum, glycogen and interaction with pericytic processes in the endothelial cells of the placentae with hypertensive disorders of pregnancy when compared to normal placentae. CONCLUSIONS: Significant changes were observed in endothelial cells at the ultrastructural level in the placentae of women with hypertensive disorders of pregnancy.
Interaction between pericytes and endothelial cell of foetal capillaries in hypertensive placentae
(Sri Lanka Medical Association, 1998) Salgado, S.; Angunawela, P.; Sirisena, J.; de Tissera, A.
INTRODUCTION : Pericytes and endothelial cells are known to possess direct contacts in many parts of the vascular tree. Pericytes are known to have modulating effects on endothelial cell growth and differentiation. It is possible that some pericytes are a source of new endothelial cell. OBJECTIVES : Information regarding the ultrastructural changes of foetal capillaries of hypertensive placentae is lacking. Therefore we studied the foetal capillaries of hypertensive placentae to ascertain any significant ultrastructural interaction between pericytes. endothelial cells and basement membrane. METHOD : Placental tissue from 15 pregnant mothers with a blood pressure of 140/90 or more and 10 normal mothers who had normal full term deliveries were studied. Fresh placentae were examined and 2mm sized pieces were taken from central foetal and fixed in 2% gluteraldehyde for eletron microscopic studies. RESULTS : All hypertensive placentae showed a number of pericytic processes, which was significantly higher than in normal placentae. (P<0.001). Both frequency and complexity of direct connections between endothelial cells and pericytes appear to be increased in foetal capi 1 laries of hypertensive placentae . Basement membranes of foetal capillaries in 9 hypertensive placentae showed marked thickening. CONCLUSIONS : There was complexed interaction between endothelial cells and pericytes of foetal capillaries of hypertensive placentae.
Ultrastructure of endothelial cells of fetal capillaries of placentae of women with pregnancy induced hypertention
(University of Colombo, 2006) Salgado, S. S.; Angunawela, P.; de Tissera, A.; Sirisena, J.
The present study aimed to compare the ultra structural features of endothelial cells of fetal terminal capillaries of placentae from hypertensive (n=10) and non-hypertensive (n=10) pregnancies. The ultrastructural features of endothelial cells of terminal capillaries from the fetal surface of each placenta were examined under the electron microscope. Micrographs of 8 different endothelial cells from each placenta were prepared for evaluation by stereological analysis using a coherent double lattice test system. The volume fractions of different organelles and cytosol in endothelial cells of placental fetal capillaries of both hypertensive and non-hypertensive pregnancies were deter¬mined by counting the number of grid intersection points falling on the endothelial cell cytoplasm, mitochondria, rough endoplasmic reticulum and glycogen deposits. Ultrastructural changes were noted in endothelial cells of capillaries of placentae of mothers with pregnancy induced hypertension. Statistical analysis showed that the volume fractions of the organelles and the amount of cytoplasm of endothelial cells of placentae from hypertensive pregnancies were significantly higher than those from non-hypertensive pregnanciesThere was a significant increase in some of the organelles and the capacity of cytoplasm of endothelial cells of placentae from hypertensive pregnancies when compared to normotensive pregnancies. These findings may be attributed to compensatory mechanisms operating as a response to hypoxia caused by reduced maternal blood flow to the placenta.
Villous syncytial knots in hypertensive placenta
(Sri Lanka College of Obstetricians and Gynaecologists, 2004) Salgado, S. S.; Angunawela, P.; de Tissera, A.; Sirisena, J.
Syncytial knots are seen on many terminal villi of all mature placentae. Syncytial knots in more than 30 percent of mature terminal villi, is considered as an indication of postmaturity. The aim of this study was to find out whether there is significant increase in syncytial knot formation in pre-eclampsia and to assess the relationship between syncytial knot formation and maternal age, parity, and period of gestation and effects of syncytial knots on the birthweight, and apgar score of the newborn. The study sample consisted of 150 normal and 200 hypertensive mothers. Light microscopic studies were done on sections taken from fetal surface of their placentae. Hundred terminal villi in fetal subdivisions of each placenta were counted and the number of villi with syncytial knots was recorded. Multivariate analysis was done to find out the difference between the number of placentae with high syncytial knot counts in normal and hypertensive groups and the relationship between high syncytial knot counts and the maternal age, parity, period of gestation and birthweight, head circumference and apgar score of the newborn. Statistically significant increase of syncytial knot counts was seen in hypertensive group than the normal group. There was no relationship between syncytial knot formation and maternal age and parity. In normal and hypertensive groups, an increase in the number of placentae with high syncytial counts was observed with increasing maturity. Although the number of placentae with high syncytial knot counts were higher in relation to low apgar score than the normal counts, difference was not statistically significant. A significant difference in the birth weight and the head circumference of newborns in relation to normal and high syncytial knot counts was observed in hypertensive group.