Faculty Bibliography

Combinations of DL-alpha-difluoromethylornithine (DFMO; eflornithine; Ornidyl) with either suramin or melarsen oxide were found to be effective against acute laboratory model infections with Trypanosoma brucei rhodesiense. We used clinical isolates known to be resistant to these drugs when used singly. An infection with a melarsen oxide-refractory isolate was cured by a combination of low-dose DFMO (0.5% in the drinking water) plus low-dose suramin (1 mg/kg of body weight given intraperitoneally). Another strain, moderately resistant to arsenical drugs, was cured with combinations of 4% DFMO with 5 mg of melarsen oxide per kg. Furthermore, a combination of DFMO (2% in the drinking water) and suramin (20 mg/kg) provided a 100% cure rate in a central nervous system model, although the same doses of these drugs used singly were completely ineffective. The synergism of DFMO and suramin against an acute infection was improved when suramin was given at the end of the DFMO administration. No adverse interactions were observed when high doses of DFMO combined with high doses of suramin were administered to uninfected mice. These results suggest that combinations of DFMO and suramin should be examined clinically for activity in arsenical-drug-refractory cases of East African sleeping sickness

On the basis of our previous demonstration of the high inhibitory activity of a series of p-n-alkyloxybenzhydroxamic acids and n-alkyl esters of 3,4-dihydroxybenzoic acid against the trypanosome alternative oxidase in a cell-free mitochondrial preparation of Trypanosoma brucei brucei, we synthesized a series of N-n-alkyl-3,4-dihydroxybenzamides for evaluation as inhibitors of this enzyme. This class of compounds was selected with the expectation of their having similar inhibitory activity to but greater solubility than the esters and hydroxamic acids noted above and greater resistance to serum hydrolases in vivo. We predicted that such properties would allow an inhibitor of the trypanosome alternative oxidase to be coadministered with glycerol as a means of providing treatment for infections by African trypanosomes. As expected, such benzamides were both more soluble and more stable, some being more active against the target enzyme than the corresponding ester. One, N-n-butyl-3,4-dihydroxybenzamide, was selected for evaluation in vivo against T. brucei brucei. When combined with glycerol, this benzamide was found to be curative. A regimen wherein 450 mg of N-n-butyl-3,4-dihydroxybenzamide per kg and 15 g of glycerol per kg were given hourly in three divided doses cured 17 of 19 mice with established T. brucei brucei infections. This combination is more active in vivo than any other designed to block simultaneously both the unique respiratory electron transport system and the anaerobic glycolytic pathways of these pathogenic protozoa

5' 32P-labeled-26-mer oligo-deoxyribonucleotide probe was used with a 'dot blot' apparatus to detect and measure the amount of Pneumocystis carinii rRNA in the total RNA extracted from rat lungs. The results of this DNA/RNA hybridization technique correlated well with standard cytological means of counting P. carinii while offering objectivity and superior precision

This paper debunks three widely believed myths about the former Yugoslavia's health care system: that it was characterized by: (1) social ownership of "self-managing" provider organizations; (2) a commitment to primary health care; and (3) a faith in what might be called the "march of progress"--the health system's continuous expansion and improvement. In contrast to this picture, we present an alternative view and conclude with a word of caution for American consultants and health care reformers in Eastern European countries and newly independent states: If universal health coverage is to be maintained, beware of reforms that do no more than substitute private for public organizational forms.

Intermediate and short stumpy bloodstream forms of Trypanosoma brucei brucei are transitional stages in the differentiation of mammal-infective long slender bloodstream forms into the procyclic forms found in the midgut of the tsetse vector. Although the mitochondria of the proliferative long slender forms do not accumulate rhodamine 123, the mitochondria of the transitional forms attain this ability thus revealing the development of an electromotive force (EMF) across the inner mitochondrial membrane. The EMF is inhibited by 2,4-dinitrophenol, rotenone and salicylhydroxamic acid but not by antimycin A or cyanide. Consequently, NADH dehydrogenase, site I of oxidative phosphorylation, is the source of the EMF and the plant-like trypanosome alternative oxidase (TAO) supports the electron flow serving as the terminal oxidase of the chain. Although the TAO is present in the long slender forms as well, it serves only as the terminal oxidase for electrons from glycerol-3-phosphate dehydrogenase. The data presented here, combined with older data, lead to the conclusion that the mitochondria of transitional intermediate and short stumpy forms likely produce ATP. This putative production is either by F1F0 ATPase driven by the complex I proton pump or by mitochondrial substrate level phosphorylation, or most likely by both. These conclusions contrast with the previously held dogma that all bloodstream form mitochondria are incapable of ATP production

The iron chelator deferoxamine and the polyamine biosynthesis inhibitor eflornithine (DL-alpha-difluoromethylornithine) were examined for anti-Pneumocystis carinii activity in the rat model of P. carinii pneumonia. The activity of deferoxamine at 250, 500, and 1,000 mg/kg given intraperitoneally provides evidence that iron chelation is a promising novel approach to P. carinii chemotherapy. Results with eflornithine at 2, 3, and 4% in drinking water confirm and extend previously reported activity in the rat model

DL-alpha-Difluoromethylornithine is an enzyme-activated inhibitor of ornithine decarboxylase and an antagonist of polyamine metabolism that has been successful in clinical trials against West African sleeping sickness caused by Trypanosoma brucei gambiense. Its potential for use against the more virulent East African form of the disease, caused by T. brucei rhodesiense, is not certain. We examined 14 East African clinical isolates from the Kenya Trypanosomiasis Research Institute strain bank plus 2 established isolates for susceptibility to DL-alpha-difluoromethylornithine and to standard trypanocides. Seven of 16 strains were partially or totally refractory to DL-alpha-difluoromethylornithine in our test system. Four strains were also refractory to arsenical drugs, and five were refractory to diamidines. The results indicate that other novel agents or combinations of established agents may be needed for chemotherapy of East African disease