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Biomedical subjects

C Canfield

Publications and source records attributed to C Canfield.

8 recordsLinked to original sources
PubMed1994

Randomised trial of mefloquine-tetracycline and quinine-tetracycline for acute uncomplicated falciparum malaria.

The combination of mefloquine plus tetracycline was compared with quinine plus tetracycline in a randomised therapeutic trial in 102 patients with acute uncomplicated falciparum malaria in Thailand. Quinine plus tetracycline is considered the standard treatment for the highly drug-resistant strains of P. falciparum found in this area. Fifty patients received mefloquine (750 mg given immediately, followed by 500 mg 6 h later) with tetracycline and 52 patients received quinine (600 mg every 8 h for seven days) with tetracycline. Tetracycline was administered to both groups in doses of 250 mg four times daily. All patients were admitted to the hospital for 28 days to exclude re-infection. Ninety-three patients completed the study; nine patients left prior to completion of follow-up for reasons unrelated to their treatment. Cure rates for the two groups were 94% (44/47) for mefloquine plus tetracycline and 98% (45/46) for quinine plus tetracycline. Parasite and fever clearance times were shorter for the group treated with mefloquine but the differences were not statistically significant. Nearly all patients (94%) treated with quinine developed cinchonism compared with only 12% treated with mefloquine; all other symptoms following treatment were similar. Thirteen patients (26%) treated with quinine also developed delayed primary attacks of P. vivax during the follow-up period; none developed in the patients treated with mefloquine. These results support the contention that the combination of mefloquine plus tetracycline is equally effective and less toxic than quinine plus tetracycline for treatment of acute uncomplicated falciparum malaria in areas requiring combination therapy for drug resistance.

Adolescent↗
PubMed1993

Exogenous epidermal growth factor fails to accelerate functional recovery in the autotransplanted ischemic pig kidney.

The reversibility of ischemic renal injury is dependent on epithelial cell regeneration and repopulation of the nephron. Renal cells produce and respond to many growth factors. In the rat, epidermal growth factor (EGF) is mitogenic for tubular cells and accelerates renal recovery after ischemia. We used a pig renal autotransplant model to evaluate the effect of exogenous EGF on renal recovery in a large animal more analogous to man. Group 1 animals underwent left autotransplant after 120 minutes of warm ischemia and received either a single intra-arterial dose of recombinant human EGF (EGF, 10(-7) M.) (N = 11) or vehicle alone (N = 6). Group 2 animals underwent left autotransplant after 72 hours of cold preservation with Collins' solution and received a similar intra-arterial dose plus a subcutaneous dose of EGF (0.5 ml. of 10(-3) M.) (N = 8) or vehicle alone (N = 6). Contralateral nephrectomy was performed in all animals. Daily creatinine measurements revealed no beneficial effect from EGF on recovery of renal function in Group 1 or 2 animals. Studies of EGF on pig proximal tubular cells demonstrated in vitro mitogenesis; autoradiography with 125I-EGF revealed binding of EGF throughout the kidney. Immunohistochemistry showed significant tubular cell proliferation in response to ischemic injury, without further enhancement from EGF. Thus, although exogenous EGF bound to pig kidney cells and stimulated cell proliferation, we were unable to demonstrate a clinically significant acceleration of recovery from ischemic injury.

Animals↗
PubMed1993

Anti-Pneumocystis carinii activity of PS-15, a new biguanide folate antagonist.

A newly synthesized biguanide inhibitor of dihydrofolate reductase in Plasmodium species was evaluated for its anti-Pneumocystis carinii activity. The compound N-3-(2,4,5-trichlorophenoxypropyloxy)-N'-(1-methylethyl)imidoca rbonimidic diamide hydrochloride, designated PS-15, was administered prophylactically and therapeutically to immunosuppressed rats latently infected with P. carinii. Doses of 5 and 25 mg of PS-15 per kg of body weight per day given orally during 7 weeks of dexamethasone immunosuppression prevented P. carinii infection in all (100%) 19 rats given the drug, while 6 of 9 (67%) untreated control rats developed P. carinii pneumonitis. A single weekly dose of 50 mg of PS-15 per kg also prevented the infection in all 10 rats. P. carinii pneumonitis was established after 4 weeks of immunosuppression and was then treated orally for 3 weeks with 25, 5, and 1 mg of PS-15 per kg/day. Complete resolution of the infection occurred in all (100%) 10 rats given 25 mg of PS-15, 6 of 9 (67%) rats given 5 mg of PS-15, and 6 of 8 (75%) rats given 1.0 mg of PS-15 per kg per day and in all (100%) 9 rats treated with trimethoprim-sulfamethoxazole. PS-15 was well tolerated at all doses. Because drug studies in the P. carinii rat model have been highly predictable of the effects of drugs on the disease in humans, these experiments suggest that PS-15 may have promise as a drug for the treatment of P. carinii pneumonitis in humans.

AIDS-Related Opportunistic Infections↗
PubMed1993

Treatment of acute uncomplicated falciparum malaria with a short course of artesunate followed by mefloquine.

The clinical results of this study indicate that a half-dose regimen of artesunate followed by mefloquine produces an acceptable cure rate when compared to other commonly available drugs for treating acute uncomplicated falciparum malaria in Thailand. The 90% cure rate was comparable to the results with either a full dose of artesunate (600 mg over 5 days) or mefloquine (25 mg/kg in divided doses six hours apart) as well as the combination of quinine-tetracycline administered for seven days. This abbreviated regimen, however was less effective than the full dose regimen of both drugs previously reported.

Acute Disease↗
PubMed1992

Randomised trial of artesunate and mefloquine alone and in sequence for acute uncomplicated falciparum malaria.

The increasing frequency of therapeutic failures in falciparum malaria in Thailand shows an urgent need for effective drugs or drug combinations. Artesunate, a qinghaosu derivative, is effective in clearing parasitaemia rapidly, but the recrudescence rate can be as high as 50%. We have compared artesunate followed by mefloquine with each drug alone in acute, uncomplicated falciparum malaria. 127 patients were randomly assigned treatment with artesunate (600 mg over 5 days), mefloquine (750 mg then 500 mg 6 h later), or artesunate followed by mefloquine. All patients were admitted to hospital for 28 days to exclude reinfection. Cure was defined as no recrudescence during the 28 days' follow-up. The cure rates for mefloquine and artesunate alone were 81% (30/37 patients) and 88% (35/40); the combination was effective in all of 39 patients. Fever and parasite clearance times were significantly shorter in the groups that received artesunate than in the mefloquine-only group. The frequency of nausea and vomiting was slightly, but not significantly, higher among patients who received both drugs than in the other groups. The combination of artesunate followed by mefloquine is highly effective and well tolerated in patients with acute, uncomplicated falciparum malaria in Thailand.

Acute Disease↗