Expectant management of intramural ectopic pregnancy.

BACKGROUND: Intramural ectopic pregnancy is unusual, difficult to diagnose, and associated with a high rate of uterine rupture. CASE: A 35-year-old, gravida 3, para 0-0-2-0 was diagnosed with intramural ectopic pregnancy by ultrasound showing a gestational sac surrounded completely by myometrium. It was confirmed by laparoscopy. With expectant management, the gestation resolved spontaneously. CONCLUSION: Early diagnosis by ultrasound of intramural ectopic pregnancy permits expectant management which, if successful, would aid in maintaining fertility.

Primary malignant schwannoma of the uterine cervix: a case report and literature review.

Primary malignant schwannomas are a very rare neural sheath tumor. A case of primary epithelioid-type malignant schwannoma of the uterine cervix in a 65-year-old woman is presented. This tumor is the first epithelioid malignant schwannoma documented within gynecologic tissues. Only two other cases of primary malignant schwannoma of the uterine cervix have been reported, and these cases are reviewed.

Oligomerization of the hydrophobic heptad repeat of gp41.

The transmembrane protein of human immunodeficiency virus type 1 (HIV-1) contains a leucine zipper-like (hydrophobic heptad) repeat which has been predicted to form an amphipathic alpha helix. To evaluate the potential of the hydrophobic heptad repeat to induce protein oligomerization, this region of gp41 has been cloned into the bacterial expression vector pRIT2T. The resulting plasmid, pRIT3, expresses a fusion protein consisting of the Fc binding domain of monomeric protein A, a bacterial protein, and amino acids 538 to 593 of HIV-1 gp41. Gel filtration chromatography demonstrated the presence of oligomeric forms of the fusion protein, and analytical centrifugation studies confirmed that the chimeric protein formed a higher-order multimer that was greater than a dimer. Thus, we have identified a region of HIV-1 gp41 which is capable of directing the oligomerization of a fusion protein containing monomeric protein A. Point mutations, previously shown to inhibit the biological activity of the HIV-1 envelope glycoprotein, have been engineered into the segment of gp41 contained in the fusion protein, and expressed mutant proteins were purified and analyzed via fast protein liquid chromatography. A point mutation in the heptad repeat, which changed the central isoleucine to an alanine, caused a significant (> 60%) decrease in oligomerization, whereas changing the central isoleucine to aspartate or proline resulted in almost a complete loss of oligomerization. Deletions of one, two, or three amino acids following the first isoleucine also resulted in a profound decrease in oligomerization. The inhibitory effects of the mutations on oligomer formation correlated with the effects of the same mutations on envelope glycoprotein-mediated fusion. A possible role of the leucine zipper-like region in the fusion process and in an oligomerization event distinct from assembly of the envelope glycoprotein complex is discussed.

Human immunodeficiency virus type 1 envelope glycoprotein is modified by O-linked oligosaccharides.

The human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein has been shown to be extensively modified by N-linked glycosylation; however, the presence of O-linked carbohydrates on the glycoprotein has not been firmly established. We have found that enzymatic deglycosylation of the HIV-1 envelope glycoprotein with neuraminidase and O-glycosidase results in a decrease in the apparent molecular weight of the envelope glycoprotein. This result was observed in both vaccinia virus recombinant-derived envelope glycoproteins and glycoproteins derived from the IIIB, SG3, and HXB2, strains of HIV-1. The decrease in molecular weight was also observed when the envelope glycoprotein had been deglycosylated with N-glycanase F after treatment with neuraminidase and O-glycosidase, indicating that the decrease in apparent molecular weight was not attributable to the removal of N-linked carbohydrate. Treatment with neuraminidase, O-glycosidase, and N-glycanase F was found to be necessary to remove all radiolabel from [3H]glucosamine-labelled envelope glycoprotein, a result seen for both recombinant and HIV-1-derived envelope glycoprotein. [3H]glucosamine-labelled carbohydrates liberated by O-glycosidase treatment were separated by paper chromatography and were found to be of a size consistent with O-linked oligosaccharides. We, therefore, conclude that the HIV-1 envelope glycoprotein is modified by the addition of O-linked carbohydrates.

Secretion of a truncated form of the human immunodeficiency virus type 1 envelope glycoprotein.

We have characterized a truncated secreted form of the HIV-1 envelope glycoprotein gene. Expression via a recombinant vaccinia virus resulted in a glycoprotein product of approximately 140 kDa (gp160t) and a minor cleavage product of 120 kDa (gp120). Pulse-chase analysis revealed that the majority of gp160t remained cell-associated and underwent degradation within 10-20 hr of synthesis. A secreted form (gp160t/sec) and gp120 were detected in the media 2-4 hr postsynthesis and were not significantly degraded within a period of 20 hr. Most of the cell-associated gp160t remained sensitive to digestion with endoglycosidase H, whereas gp160t/sec and gp120 were largely resistant. Gp160t, gp160t/sec, and gp120 formed oligomers which were stabilized by intermolecular disulfide bonds and/or noncovalent interactions and were also found to bind to soluble CD4. Both wild type gp160 and wild type gp160t were observed to undergo a post-translational modification 4-5 hr postsynthesis, resulting in glycoproteins with a slightly increased electrophoretic mobility. These differences in electrophoretic mobility remained following treatment with N-glycosidase F, indicating that they are not a consequence of N-linked oligosaccharide processing, but may represent an additional modification of the envelope glycoprotein.

Sulfation of the human immunodeficiency virus envelope glycoprotein.

Sulfation is a posttranslational modification of proteins which occurs on either the tyrosine residues or the carbohydrate moieties of some glycoproteins. In the case of secretory proteins, sulfation has been hypothesized to act as a signal for export from the cell. We have shown that the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein precursor (gp160) as well as the surface (gp120) and transmembrane (gp41) subunits can be specifically labelled with 35SO42-. Sulfated HIV-1 envelope glycoproteins were identified in H9 cells infected with the IIIB isolate of HIV-1 and in the cell lysates and culture media of cells infected with vaccinia virus recombinants expressing a full-length or truncated, secreted form of the HIV-1 gp160 gene. N-glycosidase F digestion of 35SO4(2-)-labelled envelope proteins removed virtually all radiolabel from gp160, gp120, and gp41, indicating that sulfate was linked to the carbohydrate chains of the glycoprotein. The 35SO42-label was at least partially resistant to endoglycosidase H digestion, indicating that some sulfate was linked to complex carbohydrates. Brefeldin A, a compound that inhibits the endoplasmic reticulum to Golgi transport of glycoproteins, was found to inhibit the sulfation of the envelope glycoproteins. Envelope glycoproteins synthesized in cells treated with chlorate failed to incorporate 35SO42-. However, HIV glycoproteins were still secreted from cells in the presence of chlorate, indicating that sulfation is not a requirement for secretion of envelope glycoproteins. Sulfation of HIV-2 and simian immunodeficiency virus envelope glycoproteins has also been demonstrated by using vaccinia virus-based expression systems. Sulfation is a major determinant of negative charge and could play a role in biological functions and antigenic properties of HIV glycoproteins.

Fibrous papule: a tumor of fibrohistiocytic cells that contain factor XIIIa.

Factor XIIIa, a blood coagulation factor, has been found in a variety of cell types, including dendritic reticulum cells and fibroblast-like mesenchymal cells. We hypothesized that fibrous papule, a lesion of uncertain histogenesis, was composed of dermal stellate cells and in this report demonstrate that this neoplasm consists of cells that contain this factor. Nevus cells do not contain factor XIIIa.