A new parasiticidal compound in T. solium cysticercosis.

The effect of 16α-bromoepiandrosterone (EpiBr), a dehydroepiandrosterone (DHEA) analogue, was tested on the cysticerci of Taenia solium, both in vitro and in vivo. In vitro treatment of T. solium cultures with EpiBr reduced scolex evagination, growth, motility, and viability in dose- and time-dependent fashions. Administration of EpiBr prior to infection with T. solium cysticerci in hamsters reduced the number and size of developed taenias in the intestine, compared with controls. These effects were associated to an increase in splenocyte proliferation in infected hamsters. These results leave open the possibility of assessing the potential of this hormonal analogue as a possible antiparasite drug, particularly in cysticercosis and taeniosis.

Parasiticidal effect of 16alpha-bromoepiandrosterone (EpiBr) in amoebiasis and cysticercosis.

The effect of the dehydroepiandrosterone analog 16alpha-bromoepiandrosterone (EpiBr) was tested on the tapeworm Taenia crassiceps and the protist Entamoeba histolytica, both in vivo and in vitro. Administration of EpiBr prior to infection with cysticerci in mice reduced the parasite load by 50% compared with controls. EpiBr treatment induced 20% reduction on the development of amoebic liver abscesses in hamsters. In vitro treatment of T. crassiceps and E. histolytica cultures with EpiBr, reduced reproduction, motility and viability in a dose- and time-dependent fashion. These results leave open the possibility of assessing the potential of this hormonal analog as a possible anti-parasite drug, including cysticercosis and amoebiasis.

5-androstenediol improves survival in clinically unsupported rhesus monkeys with radiation-induced myelosuppression.

We previously reported that five daily intramuscular doses of 5-androstenediol (AED), a naturally occurring adrenal steroid hormone, stimulated multilineage recovery of bone marrow in rhesus monkeys with radiation-induced myelosuppression after 4.0 Gy total body irradiation (TBI). Here we report the effect of AED on the survival of eighty rhesus macaques that received a 6.0 Gy dose of TBI in four sequential pilot studies. The drug was administered intramuscularly, based on body weight, 2-4 h after irradiation and continued once daily for a total of five injections. No clinical support in the form of antibiotics or transfusions was given to the animals at any time during the study. Five of the 40 (12.5%) treated animals died, compared to 13 of 40 (32.5%) of the animals in the control group (p=0.032). The combination of accumulated days of thrombocytopenia (<20,000 platelets/microL) up to day 14 (before the first death) together with treatment, accurately predicts mortality (p<0.001). The compound significantly reduced the duration of thrombocytopenia and neutropenia (p<0.01). The accumulation of days of neutropenia (ANC<500 cells/microL) up to day 14 plays no major role in predicting death. AED shows significant activity in irradiated primates with acute hematopoietic radiation syndrome.

5-androstenediol stimulates multilineage hematopoiesis in rhesus monkeys with radiation-induced myelosuppression.

Total body ionizing irradiation (TBI) between 2-8 Gy causes the hematopoietic component of the acute radiation syndrome (ARS) in humans. Here we report on an exploratory study with 5-androstenediol (AED) in rhesus monkeys exposed to 4 Gy (60)Co gamma TBI. In this study, the effects of two formulations administered 3-4 h after irradiation were evaluated. After radiation, severe neutropenia (<500 neutrophils/microL), thrombocytopenia (<50,000 platelets/microL), and anemia (hemoglobin <8.0 g/dL) occurred in 6, 6, and 5 of the 6 control animals, respectively. In these 6 control animals, the median time to first day of each defined cytopenia was 8.5, 13, and 20 days and the median time to last occurrence was 22.5, 19.5 and 29.5 days, respectively. All treated groups had a decrease in the duration of severe neutropenia relative to vehicle control. All but one dosing regimen decreased the duration of thrombocytopenia and anemia. Five consecutive days of a 15 mg/kg intramuscular (IM) micro-particle preparation and a once weekly 15 mg/kg subcutaneous (SC) nanoparticle suspension generally provided the greatest radiation protection. AED, as a single agent, promotes multilineage hematopoietic recovery of the bone marrow. These data suggest that it may play an important therapeutic role in the management of acute radiation syndrome.

Molecular specificity of 5-androstenediol as a systemic radioprotectant in mice.

We compared in vivo radioprotective efficacy of 5-androstenediol (5-AED) to that of ten other steroids: 17alpha-androstenediol, dehydroepiandrosterone, 5-androstenetriol (AET), 4-androstenedione (AND), testosterone, estradiol, fluasterone, 16alpha-bromoepiandrosterone, 16alpha-fluoro-androst-5-en-17alpha-ol (alpha-fluorohydrin, AFH), and 16alpha-fluoro-androst-5-en-17beta-ol (beta-fluorohydrin). Steroids were administered 24 or 48 hr before, or 1 hr after, whole-body gamma-irradiation. Two days after irradiation at 3 Gy, blood elements were counted. In addition, after irradiation at 9-12.5 Gy, survival was recorded for 30 days. The results showed radioprotective efficacy was specific for 5-AED. One other steroid, AFH, demonstrated appreciable survival effects but was less efficacious than 5-AED. AND and AET produced slight enhancement of survival in some experiments. This is the first demonstration that the prophylactic window for survival enhancement by 1 subcutaneous (s.c.) injection of 5-AED is as long as 48 hr in mice. Moreover, the results indicate that 1 s.c. injection of 5-AED 1 hr after irradiation is much less effective than 1 injection 24-48 hr before irradiation. Comparing the molecular features of steroids with radioprotective efficacy leads to the following conclusions: 1) these effects are due to interaction with specific receptors, since s.c. injection of extremely similar molecules with the same physicochemical properties as 5-AED were not radioprotective; 2) the 17-hydroxyl group is essential; 3) this group must be in the beta configuration in the absence of nearby side groups; 4) a halogen atom at 16 changes the 17-hydroxyl specificity to alpha; 5) the 3beta-hydroxyl group is not essential; 6) addition of a 7beta-hydroxyl group is deleterious; and 7) the effects are not due to activation of sex steroid receptors.