Second-Trimester Pregnancy Loss at an Urban Hospital

Objectives: Second-trimester spontaneous pregnancy losses are less common than first-trimester losses, and are often associated with ascending infection and/or acute chorioamnionitis. A Medline search revealed only two large studies published in the recent literature, reporting incidences of chorioamnionitis of 39.3% and 58.2%, respectively. These studies did not address the use of histopathology for the identification of organisms. Since ascending infection is likely to be a significant cause of second-trimester loss in the inner-city population at the University Hospital in Newark, New Jersey, we sought to evaluate the usefulness of stains for microorganisms, which are rarely utilized on these specimens. Methods: Retrospective review of the medical records and pathologic material for cases of spontaneous abortions seen at the University Hospital in Newark between January 1999 and March 2001 was undertaken. Stains for microorganisms were performed on archival placental tissue for cases with histologic acute chorioamnionitis. Results: A total of 67 cases were available for review, of which 38 cases (56.7%) showed histologic acute chorioamnionitis, similar to the rates in one previous study, but significantly higher than those in the other (p = 0.01). Of 25 cases with histological chorioamnionitis for which appropriate fetal material was available, 13 cases (52%) showed polymorphonuclear leukocytes (PMNs) in the fetal lungs, one case (4%) showed PMNs in the fetal stomach, and seven cases (28%) showed PMNs in both the lung and the stomach. Of the 38 cases with chorioamnionitis, Gram stains showed Gram-positive cocci in six cases, two of which were culture positive for group B streptococcus. Warthin–Starry stains showed filamentous organisms consistent with Fusobacterium sp. in the placenta in three cases. Conclusions: Acute chorioamnionitis is associated with second-trimester pregnancy loss at this inner-city hospital, and may be related to the high incidence of risk factors in this population. A small proportion of cases can be further characterized by the inclusion of Gram and Warthin–Starry stains in the evaluation. Selection of cases with histologic acute chorioamnionitis for further study with special stains may provide additional information on the causative organism

Influence of the Molecular Environment on Phosphorylated Amino Acid Models: A Density Functional Theory Study

A protein environment can affect the structure and charge distribution of substrate molecules. Here, the structure and partial charges were studied for different phosphorylated amino acid models in varying environments using density functional theory. The three systems investigated, acetyl phosphate, methyl phosphate, and <i>p</i>-tolyl phosphate are representative models for aspartyl phosphate, serine or threonine phosphate, and tyrosine phosphate, respectively. Combined with the CPCM continuum model, explicit HF and H₂O molecules were added in order to model environmental effects and interactions that may occur in a protein matrix. We show how the different interactions affect the scissile P–O­(R) bond and that the elongation can be explained by an anomeric effect. An increasing scissile bond length will result in transfer of negative charge to the leaving group and in a widening of the angle between the terminal oxygens of the phosphate molecule, features that can expose the phosphate group to attacking nucleophiles. Lastly, calculations were performed on the active site of the Ca²⁺-ATPase E2P intermediate, which provide an example of how a protein environment facilitates the formation of a destabilized ground state