Prolonged exposure to infection appears to influence fetal/neonatal development. We characterize the relationship between histologic patterns of inflammation and microorganism recovery from the placentas of live born infants delivered before the 28th postmenstrual week. The subamniotic parenchyma of 835 placentas delivered by cesarean section were cultured and evaluated for specific histologic patterns of inflammation in a blinded fashion. Cases with prolonged membrane rupture were excluded. Microorganisms were recovered from 41% of placentas. Microorganisms found more frequently in placentas with high-grade chorionic plate inflammation include Actinomyces, Prevotella bivia, Corynebacterium sp., Escherichia coli, Peptostreptococcus magnus, multiple species of Streptococci, and Mycoplasma sp., including Ureaplasma urealyticum. These microorganisms were also associated with fetal vasculitis (neutrophilic infiltration of chorionic plate stem vessels or umbilical cord). Recovery of microorganisms from placental parenchyma is associated with histologic inflammation. The same microorganisms responsible for inciting high-grade chorionic plate inflammation are also most likely to promote fetal inflammation.

Percutaneous transluminal angioplasty has been shown to be both feasible and efficacious for the treatment of aortic coarctation. Recent reports, however, have indicated that the development of aortic aneurysms at or near the coarctation segment may complicate attempts to treat this lesion by catheter-based intervention. Accordingly, we examined the light microscopic features of coarctation segments excised at surgery (n = 31) or obtained at autopsy (n = 2) in 33 patients with coarctation of the aorta. Cystic medial necrosis, defined as depletion and disarray of elastic tissue, was observed in each of the 33 specimens. In the majority of coarctation specimens (22 of 33 or 67%) the extent of cystic medial necrosis, graded semiquantitatively on a scale of 0 (normal aorta) to 3 +, was severe (3 + ). The finding that cystic medial necrosis represents a consistent histologic feature of coarctation of the aorta provides a pathologic basis for the formation of aneurysms observed after balloon angioplasty of coarctation sites.Circulation 75, No. 4, [689][690][691][692][693][694][695] 1987. SINCE Gruintzig's successful development of percutaneous transluminal coronary angioplasty,l catheterbased interventional techniques have been applied to an increasingly wider assortment of cardiovascular disorders. Preliminary trials of pulmonary,2 mitral,3 and aortic4 balloon valvuloplasty have yielded encouraging results. While the initial experience with balloon dilation for coarctation of the aorta was reported to be similarly favorable,5-9 recent postangioplasty followup studies in such patients have indicated that aneurysm formation at or near the coarctation segment may be a consequence of this intervention.'0' 11 Several lines of evidence have strongly suggested that aneurysm formation after coarctation angioplasty might be related to underlying aortic histopathology. First, cystic medial necrosis has been observed as a predictable consequence of aortic banding in a canine preparation of cardiac hypertrophy.'2 Second, before

Hoxb-5 expression during human lung branching morphogenesis, which is similar to that observed in mouse lung development, indicates that it plays a role in controlling airway patterning. This notion is supported by results from BPS and CCAM tissue, in which Hoxb-5 is maintained in a manner typical of an earlier developmental stage and is associated with development of abnormal lung tissue.

This study population is unique in its size and recruitment by gestational age rather than birth weight. Inflammation occurred frequently, but not in placentas that had characteristics of vasculopathy. The prevalence of inflammation decreased with increasing gestational age, while vasculopathy increased. Funisitis need not be accompanied by chorionic inflammation.