AIDS research. Keystone's blunt message: 'it's the virus, stupid'

Better drugs for Lyme disease: focus on the spirochete

Twenty-five years ago, the AIDS epidemic was wreaking havoc around the world. Although "HIV denialists" threatened to undermine research efforts to combat the epidemic, development of targeted antiviral therapy eventually provided effective treatment for the disease. Now the Lyme disease epidemic is wreaking havoc around the world, and "Lyme denialists" are undermining efforts to combat the epidemic. Drawing on our experience with the AIDS epidemic, there is a significant need to develop targeted therapy to control the Lyme disease epidemic.

The pathogenesis of HIV infection: stupid may not be so dumb after all

In the mid-1990's, researchers hypothesized, based on new viral load data, that HIV-1 causes CD4⁺ T-cell depletion by direct cytopathic effect. New data from non-human primate studies has raised doubts about this model of HIV-1 pathogenesis. Despite having high levels of viremia, most SIV infections are well tolerated by their natural hosts. Two recent studies of these models provide information, which may be useful in determining how HIV-1 causes CD4⁺ T-cell loss. A full understanding of pathogenesis may lead to novel therapies, which preserve the immune system without blocking virus replication.

Chimpanzees in AIDS Research

Although the chimpanzee displays an immunological response to an HIV-1 challenge, it is a deficient animal model in AIDS research since it never develops the progressive symptoms of the disease. The continued use of the chimpanzee is also precluded because of its endangered status in the wild, the high cost per animal, and its failure to exhibit a CD4 decline (apoptosis) while infected. However, it is likely that the chimpanzee model will continue to be used in investigations relating to the epidemiology and mucosal transmission of the human AIDS virus.

Foreign-protein-mediated immunodeficiency in hemophiliacs with and without HIV

Hemophilia-AIDS has been interpreted in terms of two hypotheses: the foreign-protein-AIDS hypothesis and the Human Immunodeficiency Virus (HIV)-AIDS hypothesis. The foreign-protein-AIDS hypothesis holds that proteins contaminating commercial clotting factor VIII cause immunosuppression. The foreign-protein hypothesis, but not the HIV hypothesis, correctly predicts seven characteristics of hemophilia-AIDS: 1) The increased life span of American hemophiliacs in the two decades before 1987, although 75% became infected by HIV--because factor VIII treatment, begun in the 1960s, extended their lives and simultaneously disseminated harmless HIV. After 1987 the life span of hemophiliacs appears to have decreased again, probably because of widespread treatment with the cytotoxic anti-HIV drug AZT. 2) The distinctly low, 1.3-2%, annual AIDS risk of hemophiliacs, compared to the higher 5-6% annual risk of intravenous drug users and male homosexual aphrodisiac drug users--because transfusion of foreign proteins is less immunosuppressive than recreational drug use. 3) The age bias of hemophilia-AIDS, i.e. that the annual AIDS risk increased 2-fold for each 10-year increase in age--because immunosuppression is a function of the lifetime dose of foreign proteins received from transfusions. 4) The restriction of hemophilia-AIDS to immunodeficiency diseases--because foreign proteins cannot cause non-immunodeficiency AIDS diseases, like Kaposi's sarcoma. 5) The absence of AIDS diseases above their normal background in sexual partners of hemophiliacs--because transfusion-mediated immunotoxicity is not contagious. 6) The occurrence of immunodeficiency in HIV-free hemophiliacs--because foreign proteins, not HIV, suppress their immune system. 7) Stabilization, even regeneration, of immunity of HIV-positive hemophiliacs by long-term treatment with pure factor VIII. This shows that neither HIV nor factor VIII plus HIV are immunosuppressive by themselves. Therefore, AIDS cannot be prevented by elimination of HIV from the blood supply and cannot be rationally treated with genotoxic antiviral drugs, like AZT. Instead, hemophilia-AIDS can be prevented and has even been reverted by treatment with pure factor VIII.

The Viral Model for AIDS: Paradigmatic Dominance, Politics, or Best Approximation of Reality?

In 1981, a non-infectious disease hypothesis was offered by the Centers for Disease Control to explain the cluster of atypical pneumonias which had appeared among gay men in the United States. Although quickly supplanted by the now widely held viral hypothesis and largely ignored by professional and media sources, that view has persisted. This article raises the question of why one explanation for the epidemic of immune system suppression has dominated the discourse on AIDS, despite the anomalies attributed to it by the proponents of other viewpoints. Alternative responses to the question are set forth drawing upon literatures in the philosophy of science and public policy formulation. Some discussion is provided of what the consequences may be if one of the contrarian hypotheses proves to be the closer approximation to the truth about AIDS etiology.

Tissue pharmacokinetics of 2',3'-dideoxyinosine in rats

The present study examined in rats the concentration-time profiles of 2',3'-dideoxyinosine (ddI) in pharmacologically relevant tissues, including organs where drug effects are desired (brain, lymph nodes, spleen), organs with known drug toxicity (pancreas), and major eliminating organs (liver, kidney). ddI was analyzed by high performance liquid chromatography and radioimmunoassay. In the liver, pancreas, spleen, brain and lymph nodes, the highest concentrations were reached between 4 and 7 min after drug administration. The concentrations subsequently declined in parallel with those in plasma, indicating that plasma and these tissues were in rapid equilibrium. The concentrations in these tissues were less or equal to that of plasma. In the kidney, the maximal concentration occurred at a later time of 14 min, after which concentrations also declined in parallel to those in plasma. The kidney concentrations were about 10-fold greater than plasma concentrations. The ratios of tissue-to-plasma concentrations and of areas under the tissue and plasma concentration-time profiles showed a 230- to 300-fold range with the rank order of kidney >> liver approximately pancreas > lymph nodes > spleen >> brain, with respective values of 10.4, 1.09, 0.90, 0.75, 0.42, and 0.04. These data indicate no accumulation of ddI in brain, lymph nodes, spleen, pancreas and liver, and a significant accumulation in the kidney. The low tissue-to-plasma ratios in brain and spleen and a moderate ratio in lymph nodes indicate that further enhancement of the therapeutic effect of ddI requires improved drug delivery and entrapment in these tissues.