An in vitro micromethod for drug sensitivity testing of Leishmania.

We describe an in vitro microtest which is quantitative, rapid, and readily applicable to parasites isolated from all major forms of human leishmaniasis. It is based on drug-mediated inhibition of promastigote catabolism of a battery of simple 14C-substrates to 14CO2. Each test requires less than 1 microCi. The test is conducted in a serum-free, chemically defined medium containing 120 micrograms protein/ml, minimizing the possible interference of drug: serum protein interaction. Prior adaptation is not necessary to cultivate "difficult-to-grow" species. Leishmania sensitivity to pentavalent antimonials is detectable at micrograms levels below concentrations achievable in patients' sera.

Quantitative in vitro drug potency and drug susceptibility evaluation of Leishmania ssp. from patients unresponsive to pentavalent antimony therapy.

Quantitative in vitro drug sensitivity of 32 Leishmania isolates (16 from patients failing pentavalent antimony [SbV] therapy) was determined using a radiorespirometric microtechnique (RAM). Of 30 isolates with histories, 22 (73%) RAM tests agreed with patient history; the remaining 8 (27%) did not. There was no difference in RAM drug sensitivity: clinical correlation between 15 isolates tested blindly and 15 with known clinical history (4 did not agree with clinical history in both). Test sensitivity appeared to be limited only by the sensitivity of the Leishmania to SbV and could be detected at 2 micrograms/ml Sb (about 10% of serum drug level). An isolate from a patient with untreated self-healing cutaneous disease was drug resistant. Using RAM, parasite drug sensitivity can be quantified apart from patient physiologic and immunologic variables intrinsic to clinical data. Potency differed a maximum of 100% (weight% Sb:weight% Sb) among drug lots and also between Glucantime and Pentostam. Potency changes between drug lots were not explainable based on Sb content or test-to-test variability. This microtest offers a rapid method for evaluating the drug sensitivity of patient isolates and for determining of the activity of pentavalent antimonials and other candidate anti-leishmanials prior to the initiation of therapy.

Biological activity of saponins from two Dracaena species.

Many species of the west African "soap tree" Dracaena are used in traditional medicine for the treatment of a variety of diseases. In continuation of our search for anti-infective agents from plants implicated in traditional medicine, we evaluated the biological activities of saponins from extracts of Dracaena mannii and Dracaena arborea by using a battery of test systems such as radiorespirometry, Cytosensor bioautography, and agar dilution methods and molluscicidal tests. Bioassay-directed fractionation of the methanol extracts of seed pulp using a combination of chromatographic techniques, gel filtration, droplet countercurrent chromatography (DCCC), and low-pressure liquid chromatography (Lobar), led to the isolation and characterization of spiroconazole A, a pennogenin triglycoside [3 beta-O-[(alpha-L-rhamnopyranosyl(1-->2), alpha-L-rhamnopyranosyl(1-->3)-beta-D-glucopyranosyl]-17 alpha-hydroxyl-spirost-5-ene] (Fig. 1). As the active constituent, spiroconazole A exhibited pronounced antileishmanial, antimalarial, and molluscicidal activities. This paper also reports on the fungistatic, fungicidal and bacteriostatic activity of spiroconazole A against 17 species of fungi and 4 of bacteria.

Evaluation of plant extracts for antileishmanial activity using a mechanism-based radiorespirometric microtechnique (RAM).

Extracts of eleven plants used in Nigerian traditional medicine have been evaluated for possible antileishmanial activity using a radiorespirometric microtest technique based on in vitro inhibition of catabolism of 14CO2 from a battery of 14C-substrates by promastigotes. Of 13 methanol extracts tested, 5 from Gongronema latifolia, Dorstenia multiradiata, Picralima nitida, Cola attiensis, and Desmodium gangeticum, were active at concentrations of 50 micrograms/ml or less against a visceral Leishmania isolate.

Safety and efficacy of intravenous sodium stibogluconate in the treatment of leishmaniasis: recent U.S. military experience.

The efficacy and toxicity of sodium stibogluconate (SSG) at a dosage of 20 mg/(kg.d) for either 20 days (for cutaneous disease) or 28 days (for visceral, mucosal, or viscerotropic disease) in the treatment of leishmaniasis is reported. Ninety-six U.S. Department of Defense health care beneficiaries with parasitologically confirmed leishmaniasis were prospectively followed for 1 year. One patient was infected with human immunodeficiency virus; otherwise, comorbidity was absent. Clinical cure occurred in 91% of 83 cases of cutaneous disease and 93% of 13 cases of visceral/viscerotropic disease. Adverse effects were common and necessitated interruption of treatment in 28% of cases, but they were generally reversible. These included arthralgias and myalgias (58%), pancreatitis (97%), transaminitis (67%), headache (22%), hematologic suppression (44%), and rash (9%). No subsequent mucosal leishmaniasis was identified, and there were no deaths attributable to SSG or leishmaniasis.