The latent structure of obsessive-compulsive symptoms: a taxometric study.

There is increasing consensus that obsessive-compulsive (OC) symptoms are heterogeneous clinical phenomena that should be assessed, diagnosed, and treated from a multidimensional perspective. However, it remains unclear whether the heterogeneous OC symptoms represent discrete taxonomic entities. In this study, the categorical versus dimensional nature of OC symptoms and associated cognitions was examined in a large undiagnosed sample using taxometric methods. Six potential OC symptoms (washing, checking, obsessing, neutralizing, ordering, and hoarding) and three potential OC-related cognitions (responsibility/threat estimation, perfectionism/certainty, and importance of thoughts/control of thoughts) were examined using the MAXimum EIGenvalue and mean above minus below a cut procedures. Findings were largely consistent with dimensional models of the latent structure of all OC symptoms and cognitions with the exception of hoarding. The implications of these findings for the clinical assessment and diagnosis of OC symptoms and obsessive-compulsive disorder are discussed.

Testing the latent structure of posttraumatic stress disorder: a taxometric study of combat veterans.

Since the diagnosis of posttraumatic stress disorder (PTSD) first appeared in the psychiatric nomenclature in 1980, considerable debate has revolved around the nature of the condition. Specifically, is PTSD best conceptualized as one end of a continuum of human response to traumatic stress or does it represent a discontinuous latent category? Two taxometric procedures were used to investigate this issue in a random community sample of 692 Australian combat veterans, using structured interview and self-report instruments to assess PTSD symptomatology. Findings favored a dimensional model of PTSD, consistent with previous taxometric work on treatment-seeking samples (A. Ruscio, Ruscio, & Keane, 2002). Implications are drawn for the conceptualization, etiology, and assessment of PTSD.

The prototype gamma-2 herpesvirus nucleocytoplasmic shuttling protein, ORF 57, transports viral RNA through the cellular mRNA export pathway.

HVS (herpesvirus saimiri) is the prototype gamma-2 herpesvirus. This is a subfamily of herpesviruses gaining importance since the identification of the first human gamma-2 herpesvirus, Kaposi's sarcoma-associated herpesvirus. The HVS ORF 57 (open reading frame 57) protein is a multifunctional transregulatory protein homologous with genes identified in all classes of herpesviruses. Recent work has demonstrated that ORF 57 has the ability to bind viral RNA, shuttles between the nucleus and cytoplasm and promotes the nuclear export of viral transcripts. In the present study, we show that ORF 57 shuttles between the nucleus and cytoplasm in a CRM-1 (chromosomal region maintenance 1)-independent manner. ORF 57 interacts with the mRNA export factor REF (RNA export factor) and two other components of the exon junction complex, Y14 and Magoh. The association of ORF 57 with REF stimulates recruitment of the cellular mRNA export factor TAP (Tip-associated protein), and HVS infection triggers the relocalization of REF and TAP from the nuclear speckles to several large clumps within the cell. Using a dominant-negative form of TAP and RNA interference to deplete TAP, we show that it is essential for bulk mRNA export in mammalian cells and is required for ORF 57-mediated viral RNA export. Furthermore, we show that the disruption of TAP reduces viral replication. These results indicate that HVS utilizes ORF 57 to recruit components of the exon junction complex and subsequently TAP to promote viral RNA export through the cellular mRNA export pathway.