Current practices and evaluation of screening solid organ donors for West Nile virus.

The first cases of West Nile virus (WNV) transmitted through solid organ transplantation (SOT) were identified in 2002. Subsequently, 5 additional clusters have been reported to public health officials in the United States. Based upon a limited number of known cases, patients who acquire WNV from infected donor organs might be at higher risk for severe neurologic disease and death, compared with patients infected through mosquito bites. In response, some organ procurement organizations (OPOs) have instituted pre-transplant screening of organ donors for WNV infection. We evaluated the current practices, concerns, and challenges related to screening organ donors for WNV in the United States by reviewing the relevant medical literature and interviewing key stakeholders. Screening organ donors for WNV is not required by national policy. In 2008, 11 (19%) of 58 OPOs performed WNV screening using nucleic acid amplification testing (NAT). These OPOs differ in their screening strategies, NAT performed, and logistical challenges. Concerns of delays in receiving NAT results before transplant and potential false-positive results leading to organ wasting are limitations to more widespread screening. Furthermore, it is unknown if WNV screening practices decrease SOT-related morbidity and mortality, or if screening is cost-effective. Additional data are needed to assess and improve transplant outcomes related to WNV.

Potential for the emergence of Japanese encephalitis virus in California.

The potential risk for the introduction and establishment of Japanese encephalitis virus (JEV) within California is described based on the literature. JEV is a mosquito-borne arbovirus endemic to Asia that when transmitted to humans can lead to Japanese encephalitis (JE), a disease affecting mostly children with a fatality rate up to 30%. The geographical expansion of JEV in Asia along with the recent introduction and rapid spread of West Nile virus (WNV) across the United States, demonstrates the ability of arboviruses to rapidly extend their distributions. California is at particular risk for the introduction of JEV because it is a large state functioning as a hub for international travel and commerce with Asia, potentially allowing the introduction of mosquitoes infected with JEV. If JEV is introduced into California, the virus might become established due to the significant number of susceptible mosquito vectors and vertebrate hosts. Once introduced, the lack of active surveillance for JEV, the ambiguous clinical presentation of JE, the cross reactivity of serological testing between JEV and other flaviviruses, and the probability that clinicians and laboratories would not consider JE as a possible diagnosis would likely delay recognition. A significant delay in detection of JEV in California would make control and eradication of the virus very difficult and costly. Public health authorities should consider the need for future control efforts if JEV emerges in the United States.

Cell-specific expression of the mouse gonadotropin-releasing hormone (GnRH) receptor gene is conferred by elements residing within 500 bp of proximal 5' flanking region.

Gonadotropin-releasing hormone (GnRH) is a decapeptide produced by the hypothalamus. Upon binding to specific high-affinity receptors on gonadotrope cells of the anterior pituitary gland, GnRH stimulates the synthesis and secretion of LH. In light of the critical role of GnRH in reproduction much effort has been directed toward understanding the regulation of this hormone and its cognate receptor. The recent availability of genomic clones for the GnRH receptor has facilitated research to address the molecular mechanisms underlying regulation of GnRH receptor gene expression. We have expanded the analysis of the promoter for the mouse GnRH receptor gene and report that in addition to transcriptional start sites located within 100 bp of the translation start codon there is a more distal transcriptional start site approximately 200 bp 5' of the initiation codon. The initiation of transcription from this more distal site was sufficient to confer cell-specific expression on luciferase. Further, transient expression assays of constructs containing progressive 5' deletions in the GnRH receptor gene promoter reveal the presence of one or morecis-acting elements located between -500 and -400 (relative to ATG) necessary for transcriptional activity in the gonadotrope-derived αT3 cell line. Finally, αT3 but not COS-7 cell nuclear extract contained protein(s) that bind to at least two separate motifs contained within the -500 to -400 region. We suggest that activation of GnRH receptor gene expression in the αT3 cell line requires the binding of at least two transcriptional regulatory proteins to basal enhancer elements located within a 100 bp region between -500 to -400 relative to the translation start codon in the mouse GnRH receptor gene.