Uterine and fetal findings at hysteroscopic evaluation of spontaneous abortions before D&C

STUDY OBJECTIVE

To evaluate the diagnostic benefit of fluid hysteroscopy before dilatation and curettage (D&C) in women with missed abortion, with respect to frequency of congenital and acquired uterine anomalies and geographic relationship of uterine anomalies to nidation site.

DESIGN

Prospective case study (Canadian Task Force classification II-2).

SETTING

Obstetric-gynecologic clinic of an academic teaching hospital.

PATIENTS

One hundred five women with one or more recurrent missed abortions.

INTERVENTION

Hysteroscopy before D&C. Inspection of the fetus was attempted in 62 patients. Control hysteroscopy of the nonpregnant uterus was performed in 20 patients.

MEASUREMENTS AND MAIN RESULTS

The uterine cavity was visualized in 87 patients (83%). These women had an obstetric history significant for 143 spontaneous abortions in 208 pregnancies. Except for three small, finger-shaped polyps in the tubal ostia, no uterine anomalies were detected. In 20 women control hysteroscopy of the nonpregnant uterus confirmed initial findings. The fetus was successfully visualized in 30 cases (48%). We observed one case of umbilical cord torsion at 12 weeks' gestation.

CONCLUSION

Absence of uterine anomalies in patients with single as well as recurrent spontaneous abortions was unexpected since it contradicts the existing literature. However, all previous data were gathered from hysteroscopies of nonpregnant uteri. Larger comparative studies are required.

A new model for in vitro clot formation that considers the mode of the fibrin(ogen) contacts to platelets and the arrangement of the platelet cytoskeleton

The constitution of platelet-fibrin(ogen) contacts, the separation of the platelets initially aggregated, and the rearrangement of the platelet cytoskeleton during clot formation (0.5 to 60 minutes after thrombin stimulation) were investigated using ultrastructural and immunocytochemical techniques. After aggregation, fibrin polymerizing within focal contacts and from degranulating secretory granules contributed to the fibers. The initially formed focal contacts with fibrin obviously persisted during clot formation. The physiological branching of the fibers enabled separation of platelets. The contact associated cytoskeleton formed a constricting and fiber internalizing sphere, but later stress fiber like bundles. As retraction progressed, the cytoskeleton changed to stress fiber connecting focal contacts with fibers. A model of clot formation in vitro is presented that reflects both the contributions of platelets (fibrin fiber internalization and retraction) and of fibers (branching) enabling the retraction.

The RafC1 cysteine-rich domain contains multiple distinct regulatory epitopes which control Ras-dependent Raf activation

Activation of c-Raf-1 (referred to as Raf) by Ras is a pivotal step in mitogenic signaling. Raf activation is initiated by binding of Ras to the regulatory N terminus of Raf. While Ras binding to residues 51 to 131 is well understood, the role of the RafC1 cysteine-rich domain comprising residues 139 to 184 has remained elusive. To resolve the function of the RafC1 domain, we have performed an exhaustive surface scanning mutagenesis. In our study, we defined a high-resolution map of multiple distinct functional epitopes within RafC1 that are required for both negative control of the kinase and the positive function of the protein. Activating mutations in three different epitopes enhanced Ras-dependent Raf activation, while only some of these mutations markedly increased Raf basal activity. One contiguous inhibitory epitope consisting of S177, T182, and M183 clearly contributed to Ras-Raf binding energy and represents the putative Ras binding site of the RafC1 domain. The effects of all RafC1 mutations on Ras binding and Raf activation were independent of Ras lipid modification. The inhibitory mutation L160A is localized to a position analogous to the phorbol ester binding site in the protein kinase C C1 domain, suggesting a function in cofactor binding. Complete inhibition of Ras-dependent Raf activation was achieved by combining mutations K144A and L160A, which clearly demonstrates an absolute requirement for correct RafC1 function in Ras-dependent Raf activation.