A synthesis of cost-utility analysis literature in infectious disease

The purpose of this review is to understand infectious disease-related cost-utility analyses by describing published analyses, examining growth and quality trends over time, examining factors related to quality, and summarising standardised results. 122 cost-utility analyses and 352 cost-utility ratios were identified. Pharmaceutical interventions were most common (47.5%); three author groups accounted for 42.8% of pharmaceutical ratios. High-volume journals (three or more published cost-utility analyses) published higher quality analyses than low-volume journals (p<0.001). Use of probabilistic sensitivity analysis and discounting at 3% were more frequently found in the years after the US Public Health Service Panel on Cost-Effectiveness in Health and Medicine recommendations (p<0.01). Median ratios varied from US13,500 dollars/quality-adjusted life year (QALY) for immunisations to US810,000 dollars/QALY for blood safety. Publication of infectious disease cost-utility analyses is increasing. The results of cost-utility analyses have important implications for the development of clinical guidelines and resource allocation decisions. More trained investigators and better peer-review processes are needed.     

Gene expression associated with interferon alfa antiviral activity in an HCV replicon cell line

Interferon alfa (IFN-alpha)-based treatment is the only therapeutic option for chronic hepatitis C viral infection. However, the molecular mechanisms of IFN-alpha antiviral activity are not completely understood. The recent development of an HCV replicon cell culture system provides a feasible experimental model to investigate the molecular details of IFN-induced direct antiviral activity in hepatocytes. In this report, we show that IFN-alpha can effectively inhibit HCV subgenomic RNA replication and suppress viral nonstructural protein synthesis. Using cDNA microarray analysis, we also show that the replicon cells have different gene expression profile compared with the parental hepatoma cells (Huh7). IFN-alpha can induce a number of responsive genes in the replicon cells. One of the genes, 6-16 (G1P3), can enhance IFN-alpha antiviral efficacy. In addition, we demonstrate that IFN-alpha can significantly activate STAT3 in hepatoma cells, suggesting that this pathway plays a role in IFN-alpha signaling. In conclusion, our results indicate that IFN-alpha antiviral activity is associated with activation of STAT3-signaling pathway and intracellular gene activation. Our results also suggest that IFN-alpha-induced target genes may play an important role in IFN-alpha anti-HCV activity.     

Stability of frozen methacholine solutions in unit-dose syringes for bronchoprovocation

OBJECTIVE: Methacholine solutions < 0.25 mg/mL must be prepared fresh daily, while concentrations > or = 0.25 mg/mL must be prepared at 2-week intervals according to US Food and Drug Administration-required labeling. The purpose of this report was to determine whether freezing methacholine solutions in unit-dose syringes would allow less frequent preparation. DESIGN: Diluent containing 0.5% sodium chloride, 0.275% sodium bicarbonate, and 0.4% phenol was used to prepare 11 concentrations of methacholine ranging from 0.031 to 32.0 mg/mL. Three milliliters of each dilution was placed into 5-mL polypropylene syringes and immediately frozen. Methacholine concentrations were determined using a validated high-performance liquid chromatography assay after preparation (time zero) and at 0.5, 1, 1.5, 2, 3, 4, 5, and 6 months. On the day of analysis, the samples were allowed to thaw to room temperature. An additional set of each dilution was stored at room temperature for 24 h after thawing and then analyzed for methacholine. RESULTS: Samples > or = 0.062 mg/mL analyzed immediately after thawing retained > or = 90% of labeled potency for at least 6 months, while the 0.031-mg/mL sample retained 90% potency for 4 months. Most samples analyzed 24 h after thawing lost potency. CONCLUSION: If prepared and stored in unit-dose syringes frozen, methacholine solutions containing 0.062 to 32.0 mg/mL can be prepared at 6-month intervals, and solutions containing 0.031 mg/mL can be prepared at 4-month intervals. Once thawed, unused methacholine solutions should be discarded.     

Chronic and Acute Prenatal and Postnatal Ethanol Exposure on Lymphocyte Subsets from Offspring Thymic, Splenic, and Intestinal Intraepithelial Sources

The overall objective of this study was to analyze the effects of a combined prenatal and postnatal (entire gestational human chronic drinking model) ethanol exposure on T-cell development in mice. Specifically, this study evaluated the effects of chronic exposure to prenatal ethanol on lymphocyte makeup and proliferative capabilities of postnatal offspring's (4 and 12 weeks) peripheral lymphoid tissues. Chronic exposure regimens were conducted over the entire gestational period and through postnatal day 14 or 21. Thymus, spleen, and intestinal intraepithelial lymphocytes were harvested and analyzed by flow cytometry for percentages of T-cell subsets. Splenic lymphocytes were also analyzed for their ability to proliferate in response to a T-cell mitogen. Limited effects of chronic ethanol exposure were seen.     

Genetic analysis of the role of cAMP in mediating effects of interferon.

The effects of interferon (IFN) on Fc receptor-mediated phagocytosis, intracellular cAMP levels, antiviral activity, and growth inhibition were analyzed in a cloned macrophage-like cell line, J774.2, and variants derived from it. Purified IFN increased Fc receptor-mediated phagocytosis in J774.2 cells, and in cAMP-responsive nonphagocytic variants but was without effect in cAMP-unresponsive nonphagocytic variants, in adenylate cyclase-deficient variants, and in cAMP-dependent protein kinase-deficient variants. Under conditions in which IFN augmented phagocytosis, it increased intracellular levels of cAMP. Parental cells were highly sensitive to IFN-mediated growth inhibition. In contrast, cAMP-dependent protein kinase-deficient variants were only 1/100th as sensitive to growth inhibition by IFN. All cell lines tested, both responsive and unresponsive to cAMP, were equally protected by IFN against infection with vesicular stomatitis virus, demonstrating that the antiviral state was independent of cAMP. These results indicate that, in transformed macrophages, stimulation of phagocytosis and inhibition of growth by IFN are mediated through intracellular cAMP, whereas the antiviral state induced by IFN is independent of cAMP.     

Enhanced green fluorescent protein targeted to the Sca-1 (Ly-6A) locus in transgenic mice results in efficient marking of hematopoietic stem cells in vivo

OBJECTIVE: Hematopoietic stem cells are important clinically, both as targets of disease and as reagents for cellular therapy. Studies in hematopoietic stem cell biology have been hampered by difficulties in purifying and manipulating these cells. To facilitate these studies, we sought to develop a system for targeting genes of interest to the hematopoietic stem cell compartment in transgenic mice. MATERIALS AND METHODS: We used Sca-1, a glycosyl phosphatidylinositol-anchored protein expressed on the surface of all hematopoietic stem cells in commonly used inbred mouse strains. We created a mutant Sca-1 allele in which the enhanced green fluorescent protein (EGFP) cDNA is integrated into the Sca-1 locus by homologous recombination in embryonic stem cells. RESULTS: EGFP protein is detectable in all hematopoietic tissues of mice heterozygous for the mutant Sca-1 allele. Growth and development of these mice are normal. No adverse effects of long-term, high-level EGFP expression were noted. Sca-1 positive cells coexpress EGFP in all tissues and lineages examined, as predicted by the targeting strategy. Sca-1 and EGFP expression are coordinately up-regulated in splenocytes from mutant mice. The Lin(-)EGFP(+) bone marrow population contains all progenitor activity in Sca-1(+)(/EGFP) mice. The Lin(-)EGFP(+) bone marrow cells are equivalent to Lin(-)Sca-1(+) cells in long-term repopulation and serial transplantation assays. CONCLUSION: The hematopoietic stem cell compartment appears to be targeted in Sca-1(+)(/EGFP) mutant mice. This system should be useful for studying the normal biology of hematopoietic stem cells and for targeting other genes to this cellular compartment.