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Standard high-dose intravenous penicillin therapy may not prevent the development of neurosyphilis in HIV-infected patients. Of 11 HIV-infected patients with symptomatic neurosyphilis, 5 had been previously treated with the standard therapy of 10 days of high-dose intravenous penicillin. None of these five cases appeared to be reinfections. Among 7 patients whose cerebrospinal fluid was analyzed 24 weeks after treatment, two had no improvement in laboratory values indicative of active neurosyphilis. Two others showed some improvement in some test values but not others. No predictors of treatment failure could be determined.

Abstract: Dopamine (DA) receptor-mediated signal transduction and gene expression play a central role in many brain disorders from schizophrenia to Parkinson''s disease to addiction. While trying to evaluate the role of L-type Ca2+ channels in dopamine D1 receptor-mediated phosphorylation of the transcription factor cyclic AMP response element-binding protein (CREB), we found that activation of dopamine D1 receptors alters the properties of L-type Ca2+ channel inhibitors and turns them into facilitators of Ca2+ influx. In D1 receptor-stimulated neurons, L-type Ca2+ channel blockers promote cytosolic Ca2+ accumulation. This leads to the activation of a molecular signal transduction pathway and CREB phosphorylation. In the absence of dopamine receptor stimulation, L-type Ca2+ channel blockers inhibit CREB phosphorylation. The effect of dopamine on L-type Ca2+ channel blockers is dependent on protein kinase A (PKA), suggesting that protein phosphorylation plays a role in this phenomenon. Because of the adverse effect of activated dopamine receptors on L-type Ca2+ channel blocker action, the role of L-type Ca2+ channels in the dopamine D1 receptor signal transduction pathway cannot be assessed with pharmacological tools. However, with antisense technology, we demonstrate that L-type Ca2+ channels contribute to D1 receptor-mediated CREB phosphorylation. We conclude that the D1 receptor signal transduction pathway depends on L-type Ca2+ channels to mediate CREB phosphorylation. [Copyright &y& Elsevier]

A response by Steven M. Gordon, Molly E. Eaton and Sheila A. Lukehart to letters to the editor about their article on neurosyphilis in patients with HIV in a previous issue is presented.

Abstract: Background: Since switching to the COBAS® AmpliPrep/COBAS® TaqMan® HIV-1 Test, v. 1.0 from the Amplicor HIV-1 Monitor Test, v. 1.5, an increase in detectable viral load results was noted. We were concerned that this was due to the use of Plasma Preparation Tubes (PPT) in this test. Objective: To assess the impact of different pre-analytical processing conditions on HIV-1 viral load results on the COBAS® AmpliPrep/COBAS® TaqMan® HIV-1 Test. Study design: Sixty-three HIV-infected patients were consented and had 3 PPTs and 1 K2EDTA drawn for HIV-1 viral load testing. Three methods of PPT processing were compared against the referent K2EDTA tube which was spun at 1100× g for 20min, poured off and frozen; PPT1 was refrigerated with an additional centrifugation prior to testing, PPT2 was processed similarly to EDTA, and PPT3 was centrifuged, frozen and centrifuged again prior to testing. Results: PPT1 and PPT3 yielded results that were most similar to the referent EDTA processing, with a concordance correlation coefficient (CCC) of 0.80 and 0.85, compared to PPT2 with CCC of 0.37. Both PPT1 and PPT3 involved additional centrifugation prior to testing. In 26 patients with residual samples from the PPT2 processing, 9 (34.6%) were found to have the presence of proviral DNA, which likely contributed to the elevated HIV-1 RNA viral loads in these individuals. Conclusion: PPTs can be used in the COBAS® AmpliPrep/COBAS® TaqMan® HIV-1 Test with an additional centrifugation in order to avoid misleading elevated HIV-1 RNA viral loads that may change patient management. [Copyright &y& Elsevier]

Infrequent and sometimes treatable noninfectious syndromes associated with HIV disease include tenofovir-associated Fanconi syndrome, a proximal renal tubular disorder; pulmonary hypertension that appears to be due to HIV-driven inflammation resulting in endothelial proliferation; thrombotic thrombocytopenic purpura, characterized by intravascular coagulopathy; diffuse infiltrative lymphocytosis syndrome, which can affect multiple organs; and Castleman's disease, a lymphoproliferative disorder that usually occurs in a multicentric form with poor prognosis in HIV-infected patients. This article summarizes a presentation on the characteristics, diagnosis, treatment, and prognosis of these disorders by Molly E. Eaton, MD, at the International AIDS Society-USA course in Atlanta in March 2005.

Dopamine (DA) receptor-mediated signal transduction and gene expression play a central role in many brain disorders from schizophrenia to Parkinson's disease to addiction. While trying to evaluate the role of L-type Ca2+ channels in dopamine D1 receptor-mediated phosphorylation of the transcription factor cyclic AMP response element-binding protein (CREB), we found that activation of dopamine D1 receptors alters the properties of L-type Ca2+ channel inhibitors and turns them into facilitators of Ca2+ influx. In D1 receptor-stimulated neurons, L-type Ca2+ channel blockers promote cytosolic Ca2+ accumulation. This leads to the activation of a molecular signal transduction pathway and CREB phosphorylation. In the absence of dopamine receptor stimulation, L-type Ca2+ channel blockers inhibit CREB phosphorylation. The effect of dopamine on L-type Ca2+ channel blockers is dependent on protein kinase A (PKA), suggesting that protein phosphorylation plays a role in this phenomenon. Because of the adverse effect of activated dopamine receptors on L-type Ca2+ channel blocker action, the role of L-type Ca2+ channels in the dopamine D1 receptor signal transduction pathway cannot be assessed with pharmacological tools. However, with antisense technology, we demonstrate that L-type Ca2+ channels contribute to D1 receptor-mediated CREB phosphorylation. We conclude that the D1 receptor signal transduction pathway depends on L-type Ca2+ channels to mediate CREB phosphorylation.