OS060. Exercise training promotes placental growth and development in an animal model of preeclampsia superimposed on chronic hypertension.

INTRODUCTION: Chronic hypertension is an important risk factor for preeclampsia, increasing the prevalence of the disease to 15-25% in pregnant women. Unfortunately there are no known treatments for this disease aside from inducing delivery of the fetus. Nonetheless, several studies have found exercise training to have a protective effect on the risk of developing preeclampsia. OBJECTIVES: To determine the mechanisms implicated in the preventive effect of exercise training on preeclampsia, by focusing on the placenta. METHODS: Double transgenic mice, overexpressing both human renin and angiotensinogen (R(+)/A(+)), were used to investigate the effect of exercise training on an animal model of preeclampsia superimposed on chronic hypertension. Mice were placed in cages with free access to an exercise wheel 4 weeks prior to and during pregnancy. At gestational day 18, mice were sacrificed and their organs were collected. Real time PCR and Western Blot were performed to evaluate placental genes and proteins, respectively. Circulating sFlt-1(soluble Fms-like tyrosine kinase-1) levels were investigated by ELISA. Placental alterations were assessed by histology and immunohistochemistry, while blood pressure was measured by radiotelemetry. RESULTS: Sedentary R(+)/A(+) mice presented with significantly greater placental pathology, which was normalized with exercise training. This was characterized by a normalization of cytokeratin and histone H3 protein expression, thereby restoring placental development, specifically looking at trophoblasts and trophoblast giant cells, respectively. This exercise training effect appears to normalize placental growth primarily by promoting angiogenesis and development. Indeed, a pro-angiogenic shift could be detected which was characterized by an increase in placental growth factor gene expression, along with a decrease in sFlt-1 gene expression, which produced a decrease in circulating sFlt-1. Sedentary R(+)/A(+) mice also presented with a significant increase in VEGF protein, which was significantly decreased with exercise. Of interest, since it has been observed to be decreased with preeclampsia, insulin regulated aminopeptidase (IRAP) gene expression was significantly increased in the trained transgenic mice. Finally, exercise training prevented the increase in blood pressure normally observed at the end of gestation in sedentary R(+)A(+) mice. CONCLUSION: Exercise training both before and during gestation appears to promote placental growth and development by producing a pro-angiogenic placental environment. Put together, along with the lack in blood pressure increase, these factors may be responsible for preventing the development of preeclampsia in our animal model of preeclampsia superimposed on chronic hypertension. Identifying the mechanisms implicated in exercise-induced preeclampsia risk reduction will be critical to improve preeclampsia prophylaxis.

Radiation damage to a DNA-binding protein. Combined circular dichroism and molecular dynamics simulation analysis.

The E. coli lactose operon, the paradigm of gene expression regulation systems, is the best model for studying the effect of radiation on such systems. The operon function requires the binding of a protein, the repressor, to a specific DNA sequence, the operator. We have previously shown that upon irradiation the repressor loses its operator binding ability. The main radiation-induced lesions of the headpiece have been identified by mass spectrometry. All tyrosine residues are oxidized into 3,4-dihydroxyphenylalanine (DOPA). In the present study we report a detailed characterization of the headpiece radiation-induced modification. An original approach combining circular dichroism measurements and the analysis of molecular dynamics simulation of headpieces bearing DOPA-s instead of tyrosines has been applied. The CD measurements reveal an irreversible modification of the headpiece structure and stability. The molecular dynamics simulation shows a loss of stability shown by an increase in internal dynamics and allows the estimation of the modifications due to tyrosine oxidation for each structural element of the protein. The changes in headpiece structure and stability can explain at least in part the radiation-induced loss of binding ability of the repressor to the operator. This conclusion should hold for all proteins containing radiosensitive amino acids in their DNA-binding site.

Ligand-escape pathways from the ligand-binding domain of PPARgamma receptor as probed by molecular dynamics simulations.

Conformational rearrangements of peroxysome proliferator activated receptor (PPARgamma) ligand-binding domain (LBD) that accompany the release and binding of ligands are not well understood. To determine the major events associated with the escape of the partial agonist GW0072, molecular dynamic (MD) simulations were performed using two different methods: reversed targeted molecular dynamics (TMD(-1)) and time-dependent distance restraints (TDR) using as restraints either the root mean square deviation from a reference structure (TMD(-1)) or the distance between the geometrical centers of the binding pocket and of the ligand (TDR). Both methods do not assume any a priori route for ligand extraction. To avoid artifacts, different initial simulation conditions were used and particular attention was paid for giving time to the protein to relax during the extraction process by running 10-12 ns simulations within explicit water. Two distinct exit gates A and B were found, independently of initial conditions and method. During the exit process no interaction between GW0072 and the transactivation AF-2 helix was observed. Our results suggest that the ligand uses the intrinsic flexibility of the protein to move within the receptor. Paths A and B are very similar to those found for other nuclear receptors, suggesting that these routes are a common characteristics of nuclear receptors that are used by different kinds of ligands. Finally, the knowledge of entry/exit pathways of a receptor should be very useful in discriminating between different ligands that could have been favorably docked in the binding pocket by introducing docking along these pathways into computational drug design protocols.

Molecular dynamics simulation for probing the flexibility of the 35 nucleotide SL1 sequence kissing complex from HIV-1Lai genomic RNA.

The SL1 stem-loop located in the encapsidation domain is responsible for initiating the dimerisation of HIV-1 genomic RNA by means of a loop-loop interaction known as Kissing Complex (KC). The SL1 secondary structure has been predicted as a 35 nucleotides [K. G. Murti, M. Bondurant, and A. Tereba. J Virol 37, 411-419 (1981)] stem-loop composed of a 4 base pairs (bp) terminal duplex, a 4 nt asymmetrical internal loop, a 7 bp internal duplex, and a 9 nt apical loop. Several high resolution structures of the monomer and of KC of a 23 nt sequence containing only the internal duplex and the apical loop of SL1 are available in the literature. No experimental high resolution structure of the complete native SL1 sequence has been reported so far, either for the monomer or for KC. The asymmetrical internal loop has been described from NMR studies of different monomeric hairpin sequences, leading to divergent results, which suggests its high flexibility. In this work, we built a SL1(35) KC model which was submitted to a 31 ns molecular dynamics simulation (MD). Our results allows to describe the internal dynamics of SL1(35) KC and the differences of behavior of the different parts of the dimer. Thus, we could show the stability of the interactions between the two apical loops and of the terminal duplexes, the destabilization of the internal duplexes and the high flexibility of the asymmetrical internal loops.

Conformational pathway for the kissing complex-->extended dimer transition of the SL1 stem-loop from genomic HIV-1 RNA as monitored by targeted molecular dynamics techniques.

HIV-1 retroviral genomic RNA dimerization is initiated by loop-loop interactions between the SL1 stem-loops of two identical RNA molecules. The SL1-SL1 unstable resulting kissing complex (KC) then refolds irreversibly into a more stable complex called extended dimer (ED). Although the structures of both types of complex have been determined, very little is known about the conformational pathway corresponding to the transition, owing to the difficulty of observing experimentally intermediate conformations. In this study, we applied targeted molecular dynamics simulation techniques (TMD) to the phosphorus atoms for monitoring this pathway for the backbone, and a two-step strategy was adopted. In a first step, called TMD(-1), the dimer structure was constrained to progressively move away from KC without indicating the direction, until the RMSD from KC reaches 36A. A total of 20 TMD(-1) simulations were performed under different initial conditions and different simulation parameters. For RMSD ranging between 0 and 22A, the whole set of TMD(-1) simulations follows a similar pathway, then divergences are observed. None of the simulations leads to the ED structure. At RMSD=22A, the dimers look like two parallel Us, still linked by the initial loop-loop interaction, but the strands of the stems (the arms of the Us) are positioned in such a manner that they can form intramolecular as well as intermolecular Watson-Crick base-pairs. This family of structure is called UU. In a second step (TMD simulations), 18 structures were picked up along the pathways generated with TMD(-1) and were constrained to move toward ED by decreasing progressively their RMSD from ED. We found that only structures from the UU family are able to easily reach ED-like conformations of the backbones without exhibiting a large constraint energy.

Fetal vasculitis in preterm newborns: interrelationships, modifiers, and antecedents.

Histologic expressions of the fetal inflammatory response predict preterm delivery and neonatal disorders. We examined 1146 placentas in the Developmental Epidemiology Network data set for histologic evidence of membrane inflammation (subchorionitis, chorionitis, and chorioamnionitis) and fetal vasculitis (acute umbilical vasculitis or chorionic vasculitis). Our main findings are that (1) in the presence of membrane inflammation, fetal vasculitis is common, (2) duration of membrane rupture and gestational age appear to modify the risk of fetal vasculitis, (3) this risk modification differs for the different components of fetal vasculitis, i.e. umbilical and chorionic vasculitis, and (4) antecedents can be identified that appear to increase or decrease the risk of fetal vasculitis among births with membrane inflammation. We conclude that fetal vasculitis, the morphologic component of the fetal inflammatory response, might not be a homogeneous entity and deserves further study.

On the stability of different experimental dimeric structures of the SL1 sequence from the genomic RNA of HIV-1 in solution: a molecular dynamics simulation and electrophoresis study.

SL1 is a stem-loop RNA sequence from the genome of HIV-1 thought to be the initiation site for the dimerization of the retroviral genomic RNA. The aim of this study is to check the stability in solution of different experimental dimeric structures available in the literature. Two kinds of dimer have been evidenced: an extended duplex looking like a double helix with two internal bulges and a kissing complex in which the monomers with a stem/loop conformation are linked by intermolecular loop-loop interactions. Two divergent experimental structures of the kissing complex from the Lai isolate are reported in the literature, one obtained from NMR (Mujeeb et al., Nature Structural Biology, 1998, Vol. 5, pp. 432-436) and the other one from x-ray crystallography (Ennifar et al., Nature Structural Biology, 2001, Vol. 8, pp. 1064-1068). A crystallographic structure of the Mal isolate was also reported (Ennifar et al., Nature Structure Biology, 2001, Vol. 8, pp. 1064-1068). Concerning the extended duplex, a NMR structure is available for Lai (Girard et al., Journal of Biomolecular Structure and Dynamics, 1999, Vol. 16, pp. 1145-1157) and a crystallographic structure for Mal (Ennifar et al., Structure, 1999, Vol. 7, pp. 1439-1449). Using a molecular dynamics technique, all these experimental structures have been simulated in solution with explicit water and counterions. We show that both extended duplex structures are stable. On the contrary, the crystallographic structures of the Lai and Mal kissing complexes are rapidly destabilized in aqueous environment. Finally, the NMR structure of the Lai loop-loop kissing complex remains globally stable over a 20 ns MD simulation, although large rearrangements occur at the level of the stem/loop junctions that are flexible, as shown from free energy calculations. These results are compared to electrophoresis experiments on dimer formation.

Base pairing at the stem-loop junction in the SL1 kissing complex of HIV-1 RNA: a thermodynamic study probed by molecular dynamics simulation.

The thermodynamics of the opening/closure process of a GC base pair located at the stem-loop junction of the SL1 sequence from HIV-1(Lai) genomic RNA was investigated in the context of a loop-loop homodimer (or kissing complex) using molecular dynamics simulation. The free energy, enthalpy and entropy changes for the closing reaction are 0 kcal x mol(-1), -11 kcal x mol(-1) and -0.037 kcal x mol(-1) x K(-1) at 300 degrees K respectively. Furthermore it is found that the free energy change is the same for the formation of a 11 nucleotide loop closed with UG and for the formation of a 9 nucleotide loop closed with GC. Our study evidences the high flexibility of the nucleotides at the stem-loop junction explaining the weak stability of this structure.

Modeling the dynamics of the solvated SL1 domain of HIV-1 genomic RNA.

A mode-coupling solution of the Smoluchowski diffusion equation (MCD theory), designed to describe the dynamics of wobbling macromolecules in water, is applied to a macromolecular bead model including water beads in the nearest layers. The necessary statistical averages are evaluated by time averaging along a molecular dynamics (MD) trajectory where both solute and water are introduced as atomistic models. The cross peaks in (1)H nuclear Overhauser effect spectroscopy (NOESY) NMR spectra that are routinely measured to determine biological structures are here calculated for the mutated 23 nucleotides stem-loop fragment of the SL1 domain in the HIV-1(Lai) genomic RNA. The calculations are in acceptable agreement with experiments without requiring any screening of the hydrodynamic interactions. The screening of hydrodynamics was necessary in previous MCD calculations obtained by using the same full atomistic MD trajectory, but a nonsolvated frictional model.

Discrimination of complete hydatidiform mole from its mimics by immunohistochemistry of the paternally imprinted gene product p57KIP2.

The p57KIP2 protein is a cell cycle inhibitor and tumor suppressor encoded by a strongly paternally imprinted gene. We explored the utility of p57KIP2 as a diagnostic marker in hydatidiform mole, a disease likely the result of abnormal dosage and consequent misexpression of imprinted genes. Using a monoclonal antibody on paraffin-embedded, formalin-fixed tissue sections, the authors evaluated p57KIP2 expression in normal placenta and in 149 gestations including 59 complete hydatidiform moles, 39 PHMs, and 51 spontaneous losses with hydropic changes. p57KIP2 was strongly expressed in cytotrophoblast and villous mesenchyme in normal placenta, all cases of partial hydatidiform moles (39 of 39) and all spontaneous losses with hydropic changes (51 of 51). In contrast, p57KIP2 expression in cytotrophoblast and villous mesenchyme was absent or markedly decreased in 58 of 59 complete hydatidiform moles. In all gestations p57KIP2 was strongly expressed in decidua and in intervillous trophoblast islands, which served as internal positive controls for p57KIP2 immunostaining. p57KIP2 immunohistochemistry can reliably identify most cases of complete hydatidiform mole irrespective of gestational age and is thus a useful diagnostic adjunct, complementary to ploidy analysis, in the diagnosis of hydatidiform mole.

Comparison of Pkd1-targeted mutants reveals that loss of polycystin-1 causes cystogenesis and bone defects.

A high level of polycystin-1 expression is detected in kidneys of all patients with autosomal dominant polycystic kidney disease (ADPKD). Mice that overexpress polycystin-1 also develop renal cysts. Whether overexpression of polycystin-1 is necessary for cyst formation is still unclear. Here, we report the generation of a targeted mouse mutant with a null mutation in Pkd1 and its phenotypic characterization in comparison with the del34 mutants that carry a 'truncation mutation' in Pkd1. We show that null homozygotes develop the same, but more aggressive, renal and pancreatic cystic disease as del34/del34. Moreover, we report that both homozygous mutants develop polyhydramnios, hydrops fetalis, spina bifida occulta and osteochondrodysplasia. Heterozygotes also develop adult-onset pancreatic disease. We show further that del34 homozygotes continue to produce mutant polycystin-1, thereby providing a possible explanation for increased immunoreactive polycystin-1 in ADPKD cyst epithelia in the context of the two-hit model. Our data demonstrate for the first time that loss of polycystin-1 leads to cyst formation and defective skeletogenesis, and indicate that polycystin-1 is critical in both epithelium and chondrocyte development.

Downregulation of placental syncytin expression and abnormal protein localization in pre-eclampsia.

Development of placentation and successful pregnancy depend on co-ordinated interactions between the maternal decidua and myometrium, and the invasive properties of the fetal trophoblast. Syncytin, a protein encoded by the envelope gene of a recently identified human endogenous defective retrovirus, HERV-W, is highly expressed in placental tissue. Previously, we have shown that the major site of syncytin expression is the placental syncytiotrophoblast, a fused multinuclear syncytium originating from cytotrophoblast cells. Here we present the first evidence that in pre-eclampsia, syncytin gene expression levels are dramatically reduced. Additionally, immunohistochemical examination of normal placentae and placentae from women with pre-eclampsia reveals that the syncytin protein in placental tissue from women with pre-eclampsia is localized improperly to the apical syncytiotrophoblast microvillous membrane as opposed to its normal location on the basal syncytiotrophoblast cytoplasmic membrane. Our previous results suggest that syncytin may mediate placental cytotrophoblast fusion in vivo and may play an important role in human placental morphogenesis. The present study suggests that altered expression of the syncytin gene, and altered cellular location of its protein product, may contribute to the aetiology of pre-eclampsia.

Should atypical squamous cells of undetermined significance (ASCUS) be subcategorized? Accuracy analysis of Papanicolaou smears using receiver operating characteristic curves and implications for the ASCUS/squamous intraepithelial lesion ratio.

We correlated all Papanicolaou test diagnoses over a 6-month period with biopsy results and determined accuracy using receiver operating characteristic curves and biopsy as the "gold standard." Accuracies were calculated using all atypical squamous cells of undetermined significance (ASCUS) cases or by eliminating subsets thereof. Retaining the ASCUS category resulted in significantly greater accuracy for the diagnosis of squamous intraepithelial lesion (SIL) on biopsy compared with eliminating it by diagnosing all such cases as negative. Subcategorization significantly improved the accuracy of the test only when all cases were included. The highest accuracy without subcategorization was achieved when ASCUS, favor reactive, cases were diagnosed as negative, but this threshold was significantly less sensitive than including all ASCUS cases. Increasing or decreasing the estimated ASCUS/SIL ratio from 2.4 without subcategorization significantly reduced accuracy. Similar results were obtained when high-grade SIL on biopsy was used as the gold standard. Use of the ASCUS category significantly improves the accuracy of the Papanicolaou test. Eliminating any subset of ASCUS reduces the ASCUS/SIL ratio but also significantly diminishes the sensitivity of the Papanicolaou test.

Partial hydatidiform mole: clinicopathological features, differential diagnosis, ploidy and molecular studies, and gold standards for diagnosis.

Partial hydatidiform mole is optimally diagnosed histopathologically when four microscopic features coexist: 1) two populations of villi, 2) enlarged villi (> or = 3-4 mm) with central captivation, 3) irregular villi with geographic, scalloped borders with trophoblast inclusions, and 4) trophoblast hyperplasia (usually focal and involving syncytiotrophoblast). Pathologic mimics of partial mole include Beckwith-Wiedemann syndrome, placental angiomatous malformation, twin gestation with complete mole and existing fetus, early complete hydatidiform mole, and hydropic spontaneous abortion. Because partial hydatidiform mole results from diandric triploidy, flow cytometry (or another method to assess ploidy) can be utilized by pathologists for supporting diagnostic classification of problematic specimens, or for educational or quality assurance purposes. Confirmation of the histopathologic diagnosis by ploidy or molecular studies is important for scientific reports of partial hydatidiform mole, especially when unusual or aggressive outcomes (such as choriocarcinoma) are reported.

Modeling the dynamics of a mutated stem-loop in the SL1 domain of HIV-1Lai genomic RNA by 1H-NOESY spectra.

The cross-peaks of 1H-NOESY spectra at different time delays are compared to a mode-coupling diffusion (MCD) calculation, including the evaluation of the full 1H relaxation matrix, in the case of a 23 nucleotide fragment of the stem-loop SL1 domain of HIV-1Lai genomic RNA mutated in a single position. The MCD theory gives significant agreement with 1H relaxation experiments enabling a thorough understanding of the differential local dynamics along the sequence and particularly of the dynamics of nucleotides in the stem and in the loop. The differential dynamics of this hairpin structure is important in directing the dimerization of the retroviral genome, a fundamental step in the infectious process. The demonstration of a reliable use of time dependent NOE cross-peaks, largely available from NMR solution structure determination, coupled to MCD analysis, to probe the local dynamics of biological macromolecules, is a result of general interest of this paper.

Placental site trophoblastic tumor: a 17-year experience at the New England Trophoblastic Disease Center.

OBJECTIVE: We reviewed cases of placental site trophoblastic tumors from the New England Trophoblastic Disease Center (NETDC) database from 1982-1999 in an effort to identify prognostic factors for recurrent disease. METHODS: A chart review was performed utilizing patients identified from the NETDC database. Data obtained included patient age at diagnosis, antecedent pregnancy, duration and extent of disease, presenting symptoms, pre- and posttreatment hCG levels, diagnostic and therapeutic procedures, treatment and outcome of patients. Statistical analysis was performed using Student's t test and chi(2) test when appropriate. RESULTS: Thirteen patients were identified. All ultimately underwent hysterectomy although initial treatment of 1 patient was uterine resection. There were 5 recurrences (43%)--3 among the 9 patients who had no metastases on presentation (33%) and 2 of 3 patients who presented with metastases (66%). The 5 patients who recurred were among 8 who had received peri- or postoperative chemotherapy (62.5%). Treatment of recurrences included continued or alternate chemotherapy, radiotherapy, and/or excision of locally recurrent disease. Follow up time averaged 56.2 months (range 12-182 months). One of the 4 patients receiving chemotherapy < or =1 week after hysterectomy recurred, whereas all 4 patients who received chemotherapy 3 weeks or more after hysterectomy recurred. Uterine tumor volume was significantly greater, 154.1 cm(3), in patients with initial metastases versus 42.3 cm(3) in patients without initial metastases (P = 0.04). Mitotic index (P = 0.04) was significantly increased in patients who developed recurrent disease. CONCLUSION: High mitotic index appears to be an adverse prognostic indicator for recurrence. Hysterectomy remains the mainstay of treatment. Chemotherapy is indicated for patients with metastases and may be indicated when the mitotic index is >5 mitoses/10 HPF. Radiation treatment may play a role in recurrent disease but must be evaluated on a case-by-case basis.

Sonographic appearance of first trimester complete hydatidiform moles.

OBJECTIVE: Complete hydatidiform moles are now being diagnosed earlier in gestation, thus the clinical presentation and pathologic findings of complete molar pregnancy have changed. We studied the sonographic appearance of first trimester moles and the ability of ultrasound to detect them. METHODS: We reviewed the sonographic interpretation and sonograms, when available, from all patients with first trimester complete moles diagnosed at our institution from January 1988 to March 1996. RESULTS: Of the 24 patients in our study, the mean gestational age at time of the sonogram was 8.7 +/- 2.0 weeks (mean +/- SD) with a range of 5.7-12.3 weeks. The initial sonographic interpretation was a complete mole in 17 (71%) cases, partial mole versus failed pregnancy in two (8%), and failed pregnancy in five (21%) cases. Of the 22 patients with sonograms available for review, interpretation on review of the images was a complete mole in 18 (82%) cases, partial mole versus failed pregnancy in one (5%), and failed pregnancy in three (14%) cases. The typical sonographic appearance of a first trimester complete mole was a complex, echogenic, intra-uterine mass containing many small cystic spaces. CONCLUSION: The majority of first trimester complete moles demonstrate a typical ultrasound appearance such that the diagnosis can be made with ultrasound in most cases.

Very low birthweight Infant's placenta and its relation to pregnancy and fetal characteristics.

Our objective was to relate pathology of the very low birthweight (VLBW) infant's placenta to pregnancy and fetal characteristics. We correlated the pathologic features of 1146 placentas from infants with birth weights of 500-1500 g who were born between 1/1/91 and 12/31/93 to the number of gestations per pregnancy, initiator of preterm delivery, gestational age, birth weight Z score, and duration of rupture of membrane (ROM). Placental correlates of acute inflammation and villous edema were associated with preterm labor (PTL), prelabor premature rupture of membranes (PROM), lower gestational age, and higher birth weight Z score. In PTL pregnancies delivered within 1 h of membrane rupture, 61% of placentas already had membrane inflammation. Placental correlates of pregnancy-induced hypertension (PIH) were seen more commonly with PIH pregnancies, older gestational age, and lower birth weight Z score. We found a more prominent histopathologic signature for singleton than for multiple gestation placentas. The placental pathologic findings associated with the clinical diagnoses of infection, PIH, and low-birth weight Z scores in our VLBW/preterm population are similar to those in the literature regarding term pregnancies. The presence of multiple histologic findings consistent with inflammation in placentas of PTL pregnancies with duration of ROM lasting <1 h suggests that some cases of PTL are precipitated by a more long-standing infection than that previously suspected. Morphologic placental features appear to be correlates of the phenomena leading to premature delivery. Examination of the VLBW infant's placenta provides insight into the etiology and management of VLBW/preterm deliveries.

Very low birthweight placenta: clustering of morphologic characteristics.

Our objective was to use factor analysis as a data reduction tool to organize a large number of placental pathologic features into useful aggregates. We examined 1146 placentas of live-born infants with a birth weight of 500-1500 g. We then conducted analyses of pairs of characteristics and multiple characteristics to identify "associated groups" and "factors," respectively. We found an associated group and factor that had placental features associated with acute inflammation and another associated group and factor that had features associated with vasculopathy. Acute umbilical vasculitis had the strongest correlation with other features of the acute inflammation associated group and factor. Gross evidence of acute inflammation (opacification and green appearance of membrane) was eliminated in the reduction from associated group to factor. Infarcts and syncytial knots were strongly dissociated with features of acute inflammation. The multiple pathologic features of the very low birthweight placenta can be aggregated into two associated groups or two factors. Lack of membrane opacification cannot be used as a criterion for declining microscopic examination. The absence of infarcts and syncytial knots should prompt a search for features of acute inflammation. If a placenta has two or more findings from the acute inflammation factor or the vasculopathy factor, it is unlikely to demonstrate features from the other factor.

Expression of epidermal growth factor receptor-related family products in gestational trophoblastic diseases and normal placenta and its relationship with development of postmolar tumor.

OBJECTIVE: The goal of this work was to study the expression of epidermal growth factor receptor (EGFR) and c-erbB-3 and c-erbB-4 oncogenes in gestational trophoblastic diseases and normal first-trimester placenta. STUDY DESIGN: Paraffin sections of 16 cases of partial mole, 25 cases of complete mole, 10 cases of gestational choriocarcinoma, and 11 cases of therapeutic abortion were studied immunohistochemically for EGFR, c-erbB-3, and c-erbB-4 proteins. The presence of EGFR mRNA was studied using in situ hybridization. RESULTS: Staining for EGFR was detected immunohistochemically in all cell types in gestational trophoblastic diseases and normal placenta. In situ hybridization for EGFR mRNA correlated with immunostaining for EGFR in all tissues studied. All 10 cases of choriocarcinoma exhibited strong immunoreactivity for EGFR. The levels of expression of EGFR in choriocarcinoma and syncytiotrophoblasts and cytotrophoblasts in complete mole were significantly greater than those in syncytiotrophoblasts and cytotrophoblasts in both normal placenta and partial mole (P < 0.01, P < 0.01). Expression of c-erbB-3 did not significantly differ among placental and gestational trophoblastic disease tissues and trophoblastic cell types except for significantly increased expression in choriocarcinoma as compared with cytotrophoblasts of partial mole (P = 0.02). The placenta, complete and partial mole, and choriocarcinoma tissues demonstrated similar immunoreactivity for c-erbB-4. Strong immunostaining for EGFR (P = 0.02) and c-erbB-3 (P < 0.01) in extravillous trophoblasts of complete mole was found to be significantly correlated with the development of persistent postmolar gestational trophoblastic tumor. CONCLUSION: The EGFR-related family of oncogenes may be important in the pathogenesis of gestational trophoblastic diseases. The increased expression of EGFR and c-erbB-3 in complete mole may also influence the development of persistent gestational trophoblastic tumor.