Culture-adapted Plasmodium falciparum isolates from UK travellers: in vitro drug sensitivity, clonality and drug resistance markers.

BACKGROUND: The screening of lead compounds against in vitro parasite cultures is an essential step in the development of novel anti-malarial drugs, but currently relies on laboratory parasite lines established in vitro during the last century. This study sought to establish in continuous culture a series of recent Plasmodium falciparum isolates to represent the current parasite populations in Africa, all of which are now exposed to artemisinin combination therapy. METHODS: Pre-treatment P. falciparum isolates were obtained in EDTA, and placed into continuous culture after sampling of DNA. One post-treatment blood sample was also collected for each donor to monitor parasite clonality during clearance in vivo. IC50 estimates were obtained for 11 anti-malarial compounds for each established parasite line, clonal multiplicity measured in vivo and in vitro, and polymorphic sites implicated in parasite sensitivity to drugs were investigated at the pfmdr1, pfcrt, pfdhfr, pfdhps and pfap2mu loci before and after treatment, and in the cultured lines. RESULTS: Plasmodium falciparum isolates from seven malaria patients with recent travel to three West African and two East African countries were successfully established in long-term culture. One of these, HL1211, was from a patient with recrudescent parasitaemia 14 days after a full course of artemether-lumefantrine. All established culture lines were shown to be polyclonal, reflecting the in vivo isolates from which they were derived, and at least two lines reliably produce gametocytes in vitro. Two lines displayed high chloroquine IC50 estimates, and carried the CVIET haplotype at codons 72-76, whereas the remaining five lines carried the CVMNK haplotype and were sensitive in vitro. All were sensitive to the endoperoxides dihydroartemisinin and OZ277, but IC50 estimates for lumefantrine varied, with the least sensitive parasites carrying pfmdr1 alleles encoding Asn at codon 86. CONCLUSIONS: This study describes the establishment in continuous culture, in vitro drug sensitivity testing and molecular characterization of a series of multiclonal P. falciparum isolates taken directly from UK malaria patients following recent travel to various malaria-endemic countries in Africa. These "HL" isolates are available as an open resource for studies of drug response, antigenic diversity and other aspects of parasite biology.

Evaluation of specific and non-specific effects in homeopathy: feasibility study for a randomised trial.

OBJECTIVE: To determine the feasibility, in terms of acceptability to patients, physicians and other staff; data return and statistical power of a study to elucidate the relative contributions of specific and non-specific effects in homeopathic treatment of dermatitis. DESIGN: Randomised, controlled 4-arm trial, 2 arms double-blind. SETTING: Outpatient clinic, Royal London Homoeopathic Hospital. PARTICIPANTS: Seventy-five adult patients with dermatitis. INTERVENTIONS: Patients were randomly allocated to: 'fast track' open verum homeopathy, 'fast track' double-blind verum homeopathy, 'fast track' double-blind placebo homeopathy or waiting list control. MAIN OUTCOME MEASURES: One hundred millimeter visual analogue scale of overall symptom severity; 10 point digital scores of sleep, itching, skin condition; weekly 5-point Likert scale of topical steroid use; Dermatology Life Quality Index at entry and completion. RESULTS: Recruitment was below target, but the study was acceptable to staff and feasible. Blinded patients were more likely to withdraw (P=0.021, chi2 test). After correction for baseline differences and multiple comparisons, no outcome measure showed statistically significant between group differences. Blindness appeared to have a negative effect, but this was confounded by differential withdrawal. CONCLUSIONS: A definitive trial of this design is unlikely to discriminate the relative contributions of the non-specific and specific effects to the outcome of homeopathic treatment of dermatitis, because of patient preference issues.