Matrix Metalloproteinase-1 and -9 in Human Placenta during Spontaneous Vaginal Delivery and Caesarean Sectioning in Preterm Pregnancy

Preterm birth is a major public health problem in terms of loss of life, long-term and short term disabilities worldwide. The process of parturition (both term and preterm) involves intensive remodelling of the extracellular matrix (ECM) in the placenta and fetal membranes by matrix metalloproteinases (MMPs). Our previous studies show reduced docosahexaenoic acid (DHA) in women delivering preterm. Further omega 3 fatty acids are reported to regulate MMP levels. This study was undertaken to examine the placental levels of MMPs and their association with placental DHA levels in women delivering preterm. The levels of MMP-1 and MMP-9 in 74 women delivering preterm (52 by spontaneous vaginal delivery and 22 by caesarean sectioning) and 75 women delivering at term (59 by spontaneous vaginal delivery and 16 by caesarean sectioning) were determined by enzyme-linked immunosorbent assay (ELISA) and their association with placental DHA was studied. Placental MMP-1 levels were higher (p<0.05) in women delivering preterm (both by spontaneous vaginal delivery and caesarean sectioning) as compared to those delivering at term. In contrast, placental MMP-9 levels in preterm pregnancies was higher (p<0.05) in women with spontaneous vaginal delivery while lower (p<0.05) in women delivering by caesarean sectioning. Low placental DHA was associated with higher placental MMP-9 levels. Our study suggests a differential effect of mode of delivery on the levels of MMPs from placenta. Further this study suggests a negative association of DHA and the levels of MMP-9 in human placenta although the mechanisms need further study

Modified Mac Protocol For Low Overhead And Long Delay Underwater Acoustic Communication

Efficient underwater networking is still a challenging issue due to its physical limitations, like long propagation delay. In this paper, we focus on modified medium access control (MAC) for low overhead and long delay Underwater Acoustic Communication. Here we consideringthat the handshaking process in conventional contention-based MACs is the main problem for improvement of utilization of the network channel, we propose a modified MAC protocol with Combined and Cancellation of CTS and RTS process to reduce the time overhead, and to achieve more efficient channel utilization. In Modified MAC protocol the conventional two-way handshaking is decoupled, and hence relevant nodes are able to perform other transmissions while control packets are propagating in water. Modified MAC also saves unnecessary control packets with traffic prediction, further improving the PDR and throughput. Our proposed protocol has been proven to be channel-efficient with both theoretical analysis and intensive simulations