Tumor necrosis factor alpha (TNF-alpha) is a cytokine with pleiotropic properties that is induced in a variety of pathological situations including viral infections. In this work, we analyzed the expression of TNF-alpha gene in patients with chronic hepatitis C. Serum TNF-alpha levels were found to be elevated in all chronic hepatitis C patients including those cases presenting sustained biochemical remission of the disease after interferon therapy. Untreated patients with chronic hepatitis C showed increased TNF-alpha messenger RNA (mRNA) levels in the liver and mononuclear cells as compared with healthy controls. After completion of treatment with interferon, patients experiencing sustained complete response showed values of TNF-alpha mRNA, both in the liver and in peripheral mononuclear cells, within the normal range, significantly lower than patients who did not respond to interferon and than those with complete response who relapsed after interferon withdrawal. Pretreatment values of TNF-alpha mRNA were lower in long-term responders to interferon than in cases who failed to respond to the treatment. Values of TNF-alpha mRNA in the liver or in mononuclear cells were higher in specimens with positive hepatitis C virus (HCV) RNA than in those samples where the virus was undetectable. Neither the intensity of the liver damage nor the amount of HCV RNA in serum or in cells showed correlation with the levels of TNF-alpha transcripts in peripheral mononuclear cells but it was found that high TNF-alpha values were associated with genotype 1b. In conclusion, there is an enhanced expression of TNF-alpha in HCV infection. High levels of this cytokine may play a role in the resistance to interferon therapy.

Modified oligodeoxynucleotides complementary to RNA of human immunodeficiency virus 1 (HIV-1) were tested for their ability to inhibit virally induced syncytium formation and expression of viral p24 protein. The Fig. 1. All the modified oligonucleotides were found to be resistant to nucleases such as snake venom or spleen phosphodiesterases. amounts of material for toxicity studies were made by a manual solid-support method on an Omnifit assembly (13). Unmodified oligomers were made and purified by methods described previously (2). Phosphorothioates and phosphoramidates were synthesized by a modification of the Hphosphonate procedure (14,15). To generate phosphorothioate linkages, oxidation following the final coupling and detritylation was replaced by treatment with 0.1 M sulfur in carbon disulfide/triethylamine (9:1, vol/vol) at room temperature for up to 2 hr, depending on chain length (16). For the phosphoramidates, this step was replaced by treatment with a 10% solution of the appropriate amine in carbon tetrachloride for up to 1.5 hr, depending on chain length (16).After deblocking in concentrated ammonium hydroxide (550C for 51/2 hr or room temperature for >2 days), products were purified on 2-mm-thick preparative layer plates (Merck silica gel 60) in propanol/water/concentrated ammonium hydroxide (55:35:10, vol/vol). Phosphorothioates were further purified on DEAE-cellulose and C18 silica (details will be published elsewhere). Phosphoramidates from preparative layer plates were passed through Sephadex G-25 in aqueous 30% (vol/vol) ethanol and then through C18 silica and dialyzed. In all cases, small amounts of oligomers attached to the solid support were taken before the final treatment with sulfur or amine and were oxidized with 2% iodine in pyridine/water (98:2, vol/vol) (15) to phosphodiesters. These were used for determination of base composition by enzymatic degradation to nucleosides followed by HPLC. The phosphorothioates were also characterized by polyacrylamide gel electrophoresis, where they had similar mobility to the corresponding diesters.Phosphoramidates were further characterized by hydrolysis with formic acid to the phosphodiesters (16) for comparison with authentic samples on HPLC and degradation to nucleosides for determination of nucleoside composition and integrity by HPLC. A useful indicator of oligonucleotide purity and integrity is the melting curve of its duplex with a complementary DNA Abbreviations: HIV, human immunodeficiency virus; AIDS, acquired immunodeficiency syndrome. 7079The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

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authors request that the following correction be noted. In both papers, the statement that toxicity studies in mice were performed using compound at a concentration of 640 ,ug/ml is incorrect. In all cases, various concentrations of oligodeoxynucleotides were in a volume of 1 ml of pyrogenfree distilled water.

Although hepatitis C virus (HCV) infection can be reproduced in chimpanzees, these animals are rare and expensive. Tree shrews (tupaias) are small animals, closely related to primates, which adapt easily to a laboratory environment. In this work we have investigated the susceptibility of Tupaia belangeri chinensis to HCV infection. Tupaias caught in the wild in Yunnan (China) were inoculated in China with HCV genotype 1b (study A) and in Spain with a mixture of genotypes 1b, 1a, and 3 (study B). In study B tupaias were divided into three groups: group I was inoculated without previous manipulation, group II received 750 cGy of X-ray whole-body irradiation before inoculation, and group III was used as control. Transient or intermittent viremia occurred in 34.8% (8/23) and anti-HCV in 30.4% (7/23) of tupaias in study A. In study B a transient viremia was detected in 20% (2/10) in group I and in 50% (2/4) in group II. Anti-HCV was found in 1 tupaia from group I and in 3 from group II: Viremia lasted for longer and anti-HCV tended to reach higher titers in animals which received total body irradiation. ALT elevations and nonspecific pathological changes occurred in inoculated tupaias; however, the wild nature of the animals precludes the interpretation of these changes as solely due to HCV infection. In summary our results show that T.b. chinensis are susceptible to HCV and that whole-body irradiation may possibly increase the efficiency of the infection. These animals may serve as an in vivo system for culturing HCV and addressing pathophysiological and therapeutic issues of HCV infection.