1,952 research outputs found
An unusual case of uterine rupture : a case report
CITATION: Nel, J. T. 1984. An unusual case of uterine rupture : a case report. South African Medical Journal, 65:60-61.The original publication is available at http://www.samj.org.zaAn unusual case of uterine rupture in a primigravida, in which the left leg of the infant ruptured through the posterior fundal part of the uterus, is presented. No definitive predisposing cause could be found. Some of the clinical signs and symptoms resembled those of abruptio placentae. Recording of internal uterine pressure revealed increased basal tone and frequent small contractions, are as often seen with abruptio placentae. This could possibly have been due to prostaglandin release from the injured decidua.Publisher’s versio
Structural and magnetic properties of CoPt mixed clusters
In this present work, we report a structural and magnetic study of mixed
Co58Pt42 clusters. MgO, Nb and Si matrix can be used to embed clusters,
avoiding any magnetic interactions between particles. Transmission Electron
Microscopy (TEM) observations show that Co58Pt42 supported isolated clusters
are about 2nm in diameter and crystallized in the A1 fcc chemically disordered
phase. Grazing Incidence Small Angle X-ray Scattering (GISAXS) and Grazing
Incidence Wide Angle X-ray Scattering (GIWAXS) reveal that buried clusters
conserve these properties, interaction with matrix atoms being limited to their
first atomic layers. Considering that 60% of particle atoms are located at
surface, this interactions leads to a drastic change in magnetic properties
which were investigated with conventional magnetometry and X-Ray Magnetic
Circular Dichro\"{i}sm (XMCD). Magnetization and blocking temperature are
weaker for clusters embedded in Nb than in MgO, and totally vanish in silicon
as silicides are formed. Magnetic volume of clusters embedded in MgO is close
to the crystallized volume determined by GIWAXS experiments. Cluster can be
seen as a pure ferromagnetic CoPt crystallized core surrounded by a
cluster-matrix mixed shell. The outer shell plays a predominant role in
magnetic properties, especially for clusters embedded in niobium which have a
blocking temperature 3 times smaller than clusters embedded in MgO
Positive Selection by Purified MHC Class II / Thymic Epithelial Cells In Vitro: Costimulatory Signals Mediated by B7 Are Not Involved
We have investigated the possibility that the costimulatory signals required for activation of
mature T cells also play a role in providing differentiation signals for positive selection
during T-cell development. We show that purified MHC Class II+ thymic epithelial cells are
able to support positive selection in vitro but lack both the functional capacity to deliver
costimulatory signals and expression of the costimulatory ligand B7. Our results suggest that
the additional signals provided by costimulatory ligands are not required for TCR-mediated
positive selection, although other ancillary signals provided by thymic epithelial cells may
be involved
Lagos Bat Virus, South Africa
Three more isolates of Lagos bat virus were recently recovered from fruit bats in South Africa after an apparent absence of this virus for 13 years. The sporadic occurrence of cases is likely due to inadequate surveillance programs for lyssavirus infections among bat populations in Africa
Placental Pathology in Spontaneous and Iatrogenic Preterm Birth: Different Entities With Unique Pathologic Features
INTRODUCTION: Placental pathology is an important contributor to the understanding of preterm birth and reveals major differences between spontaneous preterm birth (SPTB) and iatrogenic preterm birth (IPTB). The aim of this study was to investigate these relationships.
METHODS: Research midwives collected placentas from 1101 women with singleton pregnancies who were enrolled in the Safe Passage Study. Trained pathology technologists prepared and processed placenta specimens for macroscopic and microscopic examination by designated pathologists. Statistical analyses were done with STATISTICA version 13.
RESULTS: In SPTB we found more cases of accelerated villous maturation; however, the other features of maternal vascular malperfusion (MVM) were not present. The prevalence rate of funisitis was also increased. In IPTB, multiple features of MVM - accelerated villous maturation, distal villous hypoplasia, decidual arteriopathy, increased syncytial knots, increased perivillous fibrin, and prominent extravillous trophoblast were increased, as were features of fetal vascular malperfusion (FVM) - umbilical cord vessel thrombosis, avascular villi, and fetal vascular thrombosis. Increased syncytial knots were found in 26% of preterm stillbirths and in 29% of preterm infant demises as compared to 81% of IPTB infants alive at one year.
DISCUSSION: SPTB and IPTB differ. The detected abnormal accelerated villous maturation pattern in SPTB and preterm demises, suggests an inability of the placenta to adapt and may be a trigger for SPTB. Funisitis was the only inflammatory response significant for SPTB. MVM and FVM are implicated in IPTB, but not an inflammatory process
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