[Therapy of HIV infection: how early and how intensive?]

Three men aged 53, 25 and 34 years and 2 women aged 39 and 34 years with HIV infection had different courses with and without highly active antiretroviral therapy (HAART). Medication regimes were often complicated and adverse events occurred frequently, which led to adjustment of treatment. Since the introduction of HAART for treatment of HIV infection, a tremendous progress has been achieved, resulting in reduction of HIV related events and in reduction of fatality due to AIDS. However, besides the positive effects of this therapy, there is also a negative side of HAART. In addition to the complexity and adverse events, the medication has to be taken lifelong while non-compliance might result in resistance-mutation. If HAART might be indicated, it is necessary to weigh the pros and contras before starting with medication.

[Recurrent Plasmodium vivax malaria in spite of primaquine follow-up treatment]

Two patients, a 25-year-old woman and a 62-year-old man, with Plasmodium vivax infection, suffered repeated attacks of malaria despite standard treatment with chloroquine and subsequently primaquine. The relapses were due to a combination of decreased primaquine sensitivity and incorrect prescription of primaquine. Primaquine is administered as diphosphate (salt), but the required amount has to be prescribed as base (26.3 mg diphosphate corresponds to 15 mg base).

Mechanism by which recombinant factor VIIa shortens the aPTT: activation of factor X in the absence of tissue factor

Clinical trials have recently begun using high concentrations of activated recombinant factor VII (rFVIIa) for the treatment of hemophilic patients with inhibitors. Unexpectedly, the activated partial thromboplastin time (aPTT) was observed to be significantly shortened during infusion of the rFVIIa. To determine the mechanism for this shortening, the effect of rFVIIa on both the prothrombin time (PT) and the aPTT of normal and various factor-deficient plasmas was examined. rFVIIa shortened the PT of all plasmas tested except FX and FV deficient plasmas. rFVIIa also shortened the aPTT of all plasmas tested except FX and FV deficient plasmas. Since there is no added tissue factor (TF) in aPTT reagents, rFVIIa appeared to shorten the aPTT in the absence of TF. To investigate this possibility, the activity of rFVIIa in a purified system containing only FX, phospholipid vesicles (1:1 PS:PC), and calcium was examined. In this system, rFVIIa activated factor X in the absence of TF. If any component of the purified system was omitted, there was no detectable activation of FX. Thus it appears that calcium and phospholipids are required for the activation of FX by rFVIIa in the absence of TF. Increasing the concentration of rFVIIa increased the rate of FX activation, but the rate of activation was always much lower than that observed with even trace amounts of tissue factor. We conclude that high concentrations of rFVIIa, in the presence of calcium and phospholipid, can directly activate FX in the absence of TF and hence account for the shortening of the aPTT in inhibitor patients treated with rFVIIa.