A practical assay of lipoate in biologic fluids and liver in health and disease.

A procedure for assaying lipoic acid concentration in biologic fluids and tissues was devised using a eukaryotic protozoan Tetrahymena thermophila. T.thermophila has a specific and sensitive (30 pg/ml) requirement for lipoic acid.

Antioxidant survey to assess antagonism to redox stress using a prokaryotic and an eukaryotic system.

Using a prokaryote (Escherichia coli) and a metazoa-resembling eukaryote (Ochromonas danica), we surveyed antioxidants which might overcome redox stress imposed by menadione sodium bisulphite (MD) and buthionine sulphoximine (BSO). BSO oxidant stress was evident only in O. danica; MD oxidant stress was evident in both organisms.

Hypovitaminosis C in patients treated with high-dose interleukin 2 and lymphokine-activated killer cells.

Patients (n = 15) with metastatic malignant melanoma, hypernephroma, and colon carcinoma received a three-phase adoptive immunotherapy protocol: phase 1, 10(5) units (high-dose) interleukin-2 (IL-2) iv every 8 h or 1 mg/m2 continuous intravenous infusion; phase 2, 6.5 d rest + leukapheresis; phase 3, 4 d of high-dose IL-2 plus three infusions of autologous lymphokine-activated killer cells. Toxicities of treatment included fever, chills, tachycardia, hypotension, vomiting, diarrhea, and fluid retention.

Role of 5'-deoxy-5'-methylthioadenosine in growth of several microbial B12 requirers.

5'-Deoxy-5'-Methylthioadenosine (MTA) figures in cellular methionine and polyamine syntheses. It replaces B12 for growth of the chrysomonad protozoan Poteriochromonas malhamensis at a ratio of MTA:B12 of approximatly 10,000,000:1 (by weight). MTA does not replace B12 for other B12-requirers, e.

Severe hypovitaminosis C occurring as the result of adoptive immunotherapy with high-dose interleukin 2 and lymphokine-activated killer cells.

Adoptive immunotherapy of human cancer was investigated in our institution as part of a National Cancer Institute extramural group study. This treatment, for patients with metastatic malignant melanoma, hypernephroma, and colon carcinoma, consisted of three phases: (a) 5 days of i.v.

Polyamines antagonize both the antileukemic activity and the reverse transcriptase stimulatory activity of 4,4'-diacetyldiphenylurea bis(guanylhydrazone) (DDUG).

(Diacetyldiphenylurea)bis(guanylhydrazone) (DDUG) functions as a cationic trypanocide antagonized in vivo by exogenous concomitant addition of the biologically active polyamine, spermine. It also inhibits the DNA polymerases of L1210 murine leukemia cells. We have found that DDUG stimulates Rauscher murine leukemia virus DNA polymerase activity in a manner similar to polyamines.

Determination of metabolically active B12 and inactive B12 analog titers in human blood using several microbial reagents and a radiodilution assay.

Metabolically active B12 analogs and inactive B12 analogs were measured in plasma, red blood cells (RBC), and pooled pernicious anemia serum. B12 values by Lactobacillus leichmannii, Escherichia coli, Euglena gracilis, and radioisotope dilution method (RIDA) as assays for total B12 (active analogs + inactive analogs) were compared to Ochromonas malhamensis values as index of only metabolically active B12. B12 values above those with O malhamensis distinguished inactive analogs from active B12.

New drug combination for experimental late-stage African trypanosomiasis: DL-alpha-difluoromethylornithine (DFMO) with suramin.

Using a previously described mouse model of late-stage African trypanosomiasis (i.e., involvement of the central nervous system), we demonstrate that a combination of DL-alpha-difluoromethylornithine (DFMO) and suramin is curative.

Antitumor phthalanilides active in acute and chronic Trypanosoma brucei brucei murine infections.

A series of phthalanilides and related compounds were tested on a short-term, fulminating, mouse infection of Trypanosoma brucei brucei (EATRO 110 isolate). The most effective compound was [4,4'-bis (4-methylimidazolin-2-yl)-terephthalanilide] which had a cure rate of 75% at 0.1 mg/kg body weight and 100% at 0.

In vivo effects of alpha-DL-difluoromethylornithine on the metabolism and morphology of Trypanosoma brucei brucei.

The EATRO 110 isolate of Trypanosoma brucei brucei was grown in rats for 60 h and the animals treated with the ornithine decarboxylase inhibitor alpha-DL-difluoromethylornithine 12 h or 36 h prior to sacrifice. Control untreated animals died 72-80 h after infection. Treated parasites were shorter and broader than the predominantly long slender forms found in untreated controls and many had two or more nuclei and kinetoplasts.

Ornithine decarboxylase in Trypanosoma brucei brucei: evidence for selective toxicity of difluoromethylornithine.

Activity of ornithine decarboxylase, the major rate limiting enzyme of polyamine biosynthesis, was determined in bloodstream trypomastigotes of Trypanosoma brucei brucei. The enzyme required pyridoxal-5'-phosphate, dithiothreitol and EDTA for optimal activity. Several properties of the enzyme were investigated and compared to the mammalian enzyme.

In vivo and in vitro activity by diverse chelators against Trypanosoma brucei brucei.

A system of prescreens and screen has been developed to select chelators as potential drugs against Trypanosoma brucei brucei EATRO 110. The chelators tested were nearly all commercially available, low molecular, and having moderate to high affinity for Fe(III). We prescreened 70 compounds showing heme-sparing or inhibitory activity in a Crithidia fasciculata growth system having excess Fe and minimal hemin.

Further studies on difluoromethylornithine in African trypanosomes.

DL-alpha-Difluoromethylornithine (DFMO), a specific enzyme-activated irreversible inhibitor of ornithine decarboxylase (ODC) was previously shown to cure mice infected with Trypanosoma brucei brucei, a parasite of game and cattle in Africa and Trypanosoma brucei rhodesiense, a human African Sleeping Sickness pathogen. Our studies now indicate that DFMO blocks ornithine decarboxylase and lowers trypanosome polyamine levels in vivo. Polyamine uptake in T.

Rapid in vitro prescreen for chelators as potential trypanocides based on growth of Crithidia fasciculata.

A rapid in vitro prescreen for Fe-binding chelators has been developed with growth of Crithidia fasciculata and the sparing of its heme requirement in a defined medium as a test system. The prescreen functions as an index of chelator-mediated Fe transport and as an index of growth inhibition, presumably by the interference with Fe and/or heme metabolism at intracellular chelatable sites. Of 161 chelators examined, 84 were active heme-sparers; 32 of these inhibited growth at low chelator concentrations.

Metal requirements of Legionella pneumophila.

Serial passage of six strains of Legionella pneumophila and one strain of Pseudomonas aeruginosa in a liquid chemically defined medium deficient in trace metals resulted in the death of five L. pneumophila strains and very limited growth in the remaining strain and the P. aeruginosa strain.

Bleomycin-induced life prolongation of mice infected with Trypanosoma brucei brucei EATRO 110.

The antitumour antibiotic bleomycin, supplied as commercial BlenoxaneR (a mixture of bleomycinic acids), at 7 or 14 mg/kg prolonged life greater than 30 days beyond death of controls without relapse or sign of trypanosomes in the peripheral blood of mice infected with Trypanosoma b. brucei EATRO 110. Control mice died in three to four days.