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Dideoxyinosine (ddI) is a drug that is considered a potential treatment for AIDS (acquired immunodeficiency syndrome) and AIDS-related complex. Zidovudine (AZT) is the only drug currently approved for treating these conditions, and has considerable toxicity. It also appears to become less effective after one year of therapy, so new agents are needed. Since ddI seems to remain in cells as long as 12 hours, it may be effective in stopping the replication of HIV (human immunodeficiency virus, the virus associated with AIDS), even if administered infrequently. This possibility was tested in 17 AIDS patients and 17 patients with AIDS-related complex. The patients received ddI intravenously once each day for two weeks, and then took one tablet orally each day for several weeks. Patients' overall clinical condition, immune function, and blood levels of p24 antigen (a viral protein that indicates how efficiently HIV is replicating) were monitored. Pancreatitis (inflammation of the pancreas) developed in two patients, painful peripheral neuropathy (nerve inflammation) in one, and changes in enzyme levels reflecting liver function occurred in five individuals. Increases in white blood cell population and in CD4 and CD8 lymphocytes (a type of white blood cell) also were noted. Levels of p24 antigen decreased in 12 of the 19 patients who were positive for p24 antigen when the study began. Energy and appetite increased and fatigue lessened for 85 percent of the 27 patients who completed at least six weeks of treatment with ddI. The maximum tolerated oral dose of ddI was 20.4 mg per kilogram of body weight per day. Overall, ddI shows promise for treating patients with severe HIV infection, but randomized, controlled studies are essential to accurately assess its efficacy. (Consumer Summary produced by Reliance Medical Information, Inc.)

Emergency department presentations of sodium nitrate poisoning are increasing in frequency. Point-of-care blood gas analysis is useful for identifying methaemoglobinaemia and other abnormalities in such patients. Topically applied nitrate is known to positively interfere with chloride measurement in both point-of-care instruments and automated analysers of the clinical chemistry laboratory. In this article, the authors describe a case of pseudohyperchloraemia caused by sodium nitrate, which was consumed orally for the purpose of suicide. Consistent with the established pattern of interference, the ABL800 (Radiometer Medical, Brønshøj Copenhagen) blood gas analyser produced spuriously high chloride results, whilst the Alinity (Abbott Diagnostics, Abbot Park, Illinois) automated analyser resulted in chloride measurements comparable to those of inductively coupled mass spectrometry (ICP-MS). Both instruments, measure chloride with ion-selective electrodes (ISEs). The ABL800 (Radiometer) uses a membrane electrode, which is vulnerable to permeation by lipophilic nitrate ions, whereas the Alinity (Abbott) employs a silver chloride redox electrode system that is resistant to precipitation of silver nitrate due to its relatively high solubility. These mechanistic differences likely explain why nitrate interferes with some point-of-care devices but does not appear to affect the results of automated analysers. [ABSTRACT FROM AUTHOR]