Cationic antitrypanosomal and other antimicrobial agents in the therapy of experimental Pneumocystis carinii pneumonia.

Cationic compounds used in the treatment of veterinary African trypanosomiasis have structural properties similar to those of pentamidine, which has been used in the therapy of human trypanosomiasis and infection with Pneumocystis carinii. We have compared the activities of these drugs and other antimicrobial agents in an immunosuppressed rat model of P. carinii pneumonia. Diminazene, imidocarb, amicarbalide, quinapyramine, and isometamidium showed efficacy greater than or equal to that of pentamidine in the therapy of P. carinii infection, whereas ethidium and methylglyoxal bis(guanylhydrazone) were only slightly active against the organism. Diminazene and pentamidine also exhibited comparable efficacy in P. carinii prophylaxis, alpha-Difluoromethylornithine (DFMO), a polyamine inhibitor, was ineffective therapy when used alone and did not improve the effectiveness of pentamidine or diminazene. Quinine, quinidine, quinacrine, chlorpromazine, spiramycin, Pentostam, Astiban, dehydroemetine, ampicillin, gentamicin, chloramphenicol, and spectinomycin also showed little or no activity against the organism. Thus, in this model anti-P. carinii activity appears to be a common property of veterinary cationic trypanocidal compounds. This should be important in studying structure-activity relationships and in developing new drugs for the treatment of P. carinii infection in humans.

A study on the neurotoxicity of broxyquinoline and brobenzoxaldine combination in therapeutic doses.

The neurotoxicity of a combination of broxyquinoline and brobenzoxaldine (Intestopan Forte, containing 500 mg and 100 mg of the drugs respectively per capsule) was investigated by prospective clinical and electrophysiological studies in patients and volunteer subjects given the drugs in therapeutic doses (two capsules three times a day for 5 days). Of 16 patients with intestinal amoebiasis given the drugs (study A), 13 (81.25%) were cured. Adverse effects were mild and did not affect treatment. No neurological adverse effect was reported. Neurological examinations revealed no abnormality in any patient after treatment. Seven volunteer subjects underwent medical, neurological and ophthalmological examinations, and electrophysiological studies of ulnar and peroneal nerve conduction before and after treatment with the drugs in therapeutic doses (study B). Transient paresthesias were reported by one subject on the fourth day of treatment. No medical, neurological or ophthalmological abnormality was detected in any subject after treatment. There was no significant change in motor nerve conduction velocities. There was a significant (P less than 0.001) increase in the stimulus strength for distal ulnar stimulation and a significant (P less than 0.01) decrease in stimulus duration for proximal and distal ulnar stimulation. No significant changes were seen in the peroneal nerves in these parameters. No qualitative abnormality was seen in the oscilloscopic patterns of nerve conduction after treatment. Literature on the neurotoxicity of the halogenated hydroxyquinolines is reviewed. It is concluded that broxyquinoline and brobenzoxaldine (and probably other halogenated hydroxyquinolines as well) are safe and effective in therapeutic doses; neurotoxicity is unlikely to occur when these drugs are used according to therapeutic recommendations.

The complement fixation test and African trypanosomiasis. II. The complement fixation test as an aid for assessing therapy.

Complement-fixing antibody titres decline after successful treatment of trypanosoma infected cattle during a fixed period. For investigating the practicability of the resulting double test procedure in the field, cattle under controlled drug regimes were tested at treatment and again 3 weeks later. Alternatively, the results from groups of treated and untreated animals from the same area were compared. Both serological and parasitological test results indicated an insuffieicnt effectiveness of therapy in the area under investibation.

Synthsis and antitumor properties of bis(quinaldine) derivatives.

A series of 7-nitro- and amino-N,'-bis(4-quinaldinyl)-alpha, omega-diaminoalkanes related to the 6-amino derivative 1 was synthesized and tested in the mouse P-388 lymphocytic leukemia screen. There of the 7-nitro derivatives (12, 14, and 15) were found to have moderate activity (T/C 140-150%), while other nitro derivatives (11 and 13) were devoid of any antitumor properties. All five 7-amino compounds (2-6) were moderately to strongly active (T/C 134-196%). In addition, binding of amino derivatives 2-6 to DNA was examined by their ability to (1) stabilize DNA to thermal denaturation and (2) inhibit the DNA-dependent RNA polymerase reaction in vitro. Tm data suggest that these compounds bind to DNA and are strong inhibitors of the polymerase reaction (I50 = 6-9 X 10(-6) M).

Babesiosis in the newborn foal.

A short account is given of babesiosis (equine biliary fever) caused by the tick-borne protozoan Babesia equi and B. caballi, endemic in the Cape Province of South Africa. The clinical picture, diagnosis and treatment are described. In the absence of any prophylactic measures, prognosis is poor; control of the parasites in the tick-infested areas is essential.