The virion host shutoff (Vhs) protein (UL41) is a minor component of herpes simplex virus virions which, following penetration, accelerates turnover of host and viral mRNAs. Infected cells contain 58-kDa and 59.5-kDa forms of Vhs, which differ in the extent of phosphorylation, yet only a 58-kDa polypeptide is incorporated into virions. In pulse-chase experiments, the primary Vhs translation product comigrated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis with the 58-kDa virion polypeptide, and could be chased to 59.5 kDa. While both 59.5-kDa and 58-kDa forms were found in nuclear and cytoplasmic fractions, the 59.5-kDa form was significantly enriched in the nucleus. Both forms were associated with intranuclear B and C capsids, yet only the 58-kDa polypeptide was found in enveloped cytoplasmic virions. A 58-kDa form, but not the 59.5-kDa form, was found in L particles, noninfectious particles that contain an envelope and tegument but no capsid. The data suggest that virions contain two populations of Vhs that are packaged by different pathways. In the first pathway, the primary translation product is processed to 59.5 kDa, is transported to the nucleus, binds intranuclear capsids, and is converted to 58 kDa at some stage prior to final envelopment. The second pathway does not involve the 59.5-kDa form or interactions between Vhs and capsids. Instead, the primary translation product is phosphorylated to the 58-kDa virion form and packaged through interactions with other tegument proteins in the cytoplasm or viral envelope proteins at the site of final envelopment.Controls of the rate of mRNA decay play an important role in eukaryotic gene expression (3, 6-9, 47, 48, 55, 66). During lytic herpes simplex virus (HSV) infections, the half-lives of host and viral mRNAs are regulated by the HSV virion host shutoff (Vhs) protein (21,34,35,52,53,56,64,73). Vhs is an endoribonuclease (12,13,16,40,41,77,87) that is a minor structural component of HSV virions (58,68) and that, following release from infecting virions, accelerates the degradation of most cellular mRNAs in the cytoplasm (21,64,73). Following the onset of viral transcription, Vhs also accelerates the turnover of viral mRNAs (34,35,52,53,73

Previous studies have correlated intolerance of isotonic, intact protein enteral solutions with hypoalbuminemia. The purpose of this retrospective study was to determine whether the level of serum albumin (SA) influenced tolerance of such an enteral nutrient solution (ENS). All patients who received Entrition during 1987 for a minimum of 48 hr were studied for the first 10 days of enteral feeding. Documentation included SA, medications, stool frequency, gastric residuals (GR), and daily caloric intake. ENS intolerance was defined as greater than 3 stools/day for greater than 48 hr or GR greater than twice the hourly infusion rate for greater than 48 hr. Patients were categorized into two groups: those with SA greater than or equal to 2.5 g/dl (group I) and those with SA less than 2.5 g/dl (group II). Of 88 patients studied, 48 (86%) in group I and 28 (88%) in group II tolerated the ENS. Eight (14%) in group I and 4 (12%) in group II experienced ENS intolerance. There was no statistically significant difference in the frequency of ENS intolerance between these two groups (p less than 0.05). Also, 97% of all those with a SA less than 2.5 g/dl were fed 80% or more of their estimated caloric requirements. We concluded that ENS tolerance was not affected by the SA level and patients with hypoalbuminemia (SA less than 2.5 g/dl) could be fed enterally.

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