Inhibitors of SARS-CoV entry--identification using an internally-controlled dual envelope pseudovirion assay.

Severe acute respiratory syndrome-associated coronavirus (SARS-CoV) emerged as the causal agent of an endemic atypical pneumonia, infecting thousands of people worldwide. Although a number of promising potential vaccines and therapeutic agents for SARS-CoV have been described, no effective antiviral drug against SARS-CoV is currently available. The intricate, sequential nature of the viral entry process provides multiple valid targets for drug development. Here, we describe a rapid and safe cell-based high-throughput screening system, dual envelope pseudovirion (DEP) assay, for specifically screening inhibitors of viral entry. The assay system employs a novel dual envelope strategy, using lentiviral pseudovirions as targets whose entry is driven by the SARS-CoV Spike glycoprotein. A second, unrelated viral envelope is used as an internal control to reduce the number of false positives. As an example of the power of this assay a class of inhibitors is reported with the potential to inhibit SARS-CoV at two steps of the replication cycle, viral entry and particle assembly. This assay system can be easily adapted to screen entry inhibitors against other viruses with the careful selection of matching partner virus envelopes.

Idiopathic itch, rash, and urticaria/angioedema merit serum vitamin D evaluation: a descriptive case series.

BACKGROUND: Vitamin D insufficiency is epidemic. Rarely are cutaneous consequences attributed to low vitamin D. METHODS: A retrospective case series of 63 patients describes an association of pruritus, rash, and urticaria/angioedema with low 25-hydroxyvitamin D (25[OH]D <32 ng/mL). The 90% (57/63) of patients with low vitamin D were treated with 8 to 12 weeks of vitamin D 50,000 IU weekly followed by daily supplementation. Concurrent diagnoses were treated routinely. Complete resolution of cutaneous symptoms defined response. RESULTS: Patients were 3 to 80 years of age. The 90% (57/63) with low vitamin D (25[OH]D < 32 ng/mL) had a mean age of 47 (11 to 80) years old, 70% were atopic, and 77% were female. Median duration of idiopathic cutaneous symptoms was 18 months. Mean 25[OH]D was 18.0 ng/mL. With vitamin D treatment 70% (40/57) had complete resolution of symptoms. Mean 25[OH]D for vitamin D responsive patients (16.8 ng/mL) was significantly lower than for vitamin D non-responsive treated patients (20.9 ng/mL, P = 0.02 by unpaired t-Test). Resolution of cutaneous symptoms with vitamin D supplementation occurred in a mean of 4.2 weeks. Symptom recurrence was seen in subsequent months only if vitamin D insufficiency recurred. CONCLUSION: This retrospective case-series, with a 70% (40/57) vitamin D treatment success, suggests that vitamin D status should be assessed in patients with idiopathic cutaneous symptoms. If vitamin D is low, symptom resolution is often possible with oral supplementation of vitamin D. Controlled clinical studies are required to confirm these associations.

Gene expression pattern in hepatic stem/progenitor cells during rat fetal development using complementary DNA microarrays.

To identify new and differentially expressed genes in rat fetal liver epithelial stem/progenitor cells during their proliferation, lineage commitment, and differentiation, we used a high throughput method-mouse complementary DNA (cDNA) microarrays-for analysis of gene expression. The gene expression pattern of rat hepatic cells was studied during their differentiation in vivo: from embryonic day (ED) 13 until adulthood. The differentially regulated genes were grouped into two clusters: a cluster of up-regulated genes comprised of 281 clones and a cluster of down-regulated genes comprised of 230 members. The expression of the latter increased abruptly between ED 16 and ED 17. Many of the overexpressed genes from the first cluster fall into distinct, differentially expressed functional groups: genes related to development, morphogenesis, and differentiation; calcium- and phospholipid-binding proteins and signal transducers; and cell adhesion, migration, and matrix proteins. Several other functional groups of genes that are initially down-regulated, then increase during development, also emerged: genes related to inflammation, blood coagulation, detoxification, serum proteins, amino acids, lipids, and carbohydrate metabolism. Twenty-eight genes overexpressed in fetal liver that were not detected in adult liver are suggested as potential markers for identification of liver progenitor cells. In conclusion, our data show that the gene expression program of fetal hepatoblasts differs profoundly from that of adult hepatocytes and that it is regulated in a specific manner with a major switch at ED 16 to 17, marking a dramatic change in the gene expression program during the transition of fetal liver progenitor cells from an undifferentiated to a differentiated state. Supplementary material for this article can be found on the HEPATOLOGY website (http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).