Hypoxia induces the expression of a 43-kDa protein (PROXY-1) in normal and malignant cells.

This study was designed to determine the expression of cellular factors that may participate in phenotypic changes that occur under conditions of hypoxia. Using the RT-PCR differential display method, we isolated a cDNA fragment corresponding to a gene whose expression was induced in trophoblast and breast carcinoma cells cultured under 1 or 2% oxygen vs 4% oxygen or higher. This gene encodes a 43-kDa protein initially identified in homocysteine-treated endothelial cells and later shown to be upregulated in various human and mouse cell types (termed RTP, Drg1, Cap43, rit42, Ndr1). Herein we refer to this gene product as PROXY-1, for Protein Regulated by OXYgen-1. Elevated mRNA and protein levels were first observed in cells cultured in 1% oxygen for 8 h. Although PROXY-1 mRNA levels returned to near-control values within 2 h of reexposure to 20% oxygen, protein levels remained high 72 h after reexposure to 20% oxygen. Treatment of cells with hypoxia mimics such as cobalt or iron chelators also increased PROXY-1 expression. Moreover, presence of 30% carbon monoxide in the hypoxic atmosphere abrogated the upregulation of PROXY-1 expression. These findings suggest that hypoxia upregulates PROXY-1 levels through a heme protein-dependent pathway and that assessment of PROXY-1 expression may be of potential use in evaluating tissue hypoxia.

Human papillomavirus type 16 virus-like particles expressed in attenuated Salmonella typhimurium elicit mucosal and systemic neutralizing antibodies in mice.

Attenuated strains of Salmonella are attractive live vaccine candidates for eliciting mucosal as well as systemic immune responses. The ability to induce immune responses in the reproductive tract may be critical for the effectiveness of a prophylactic vaccine against genital human papillomaviruses (HPV), which are important etiologic agents in the development of cervical cancer. To examine the potential of a live Salmonella-based vaccine to prevent genital HPV infection, the L1 major capsid protein from HPV type 16 (HPV16) was constitutively expressed in the PhoPc strain of Salmonella typhimurium. As demonstrated by electron microscopy, the L1 protein expressed in these bacteria assembled into virus-like particles (VLPs) that resemble authentic papillomavirus virions. This is the first demonstration that papillomavirus VLPs can self-assemble in prokaryotes. BALB/c mice were immunized with the HPV16 L1 recombinant PhoPc strain by the oral and nasal routes. Despite a low stability of the L1-expressing plasmid in vivo, a double nasal immunization was effective in inducing L1-specific serum antibodies that recognized mainly native, but not disassembled, VLPs. These antibodies effectively neutralized HPV16 pseudotyped virions in an in vitro infectivity assay. Conformationally dependent anti-VLP immunoglobulin A (IgA) and IgG were also detected in oral and vaginal secretions, indicating that potentially protective antibody responses were elicited at mucosal sites. Recombinant attenuated Salmonella expressing HPV capsids may represent a promising vaccine candidate against genital HPV infection.

[Congenital perilymphatic fistula in children]. / Fistules péri-lymphatiques congénitales chez l'enfant.

We report twenty case of perilymphatic fistulae in children. A fistula was discovered in every case where the cochlear aqueduct is larger than normal on high resolution CT scan of the temporal bone. The surgical treatment of these fistulae allowed only a significant improvement of hearing in the cases were an asymmetry or a dilatation of the cochlear aqueducts and a fluctuating deafness coexisted. Unfortunately these improvements do not look permanent.