A new primaquine analogue, tafenoquine (WR 238605), for prophylaxis against Plasmodium falciparum malaria.

We tested tafenoquine (WR 238605), a new long-acting 8-aminoquinoline, for its ability to prevent malaria in an area that is holoendemic for Plasmodium falciparum. In a double-blinded, placebo-controlled, randomized clinical trial in western Kenya, adult volunteers received a treatment course of 250 mg halofantrine per day for 3 days, to effect clearance of preexisting parasites. The volunteers were then assigned to 1 of 4 drug regimens: placebo throughout; 3 days of 400 mg (base) of tafenoquine per day, followed by placebo weekly; 3 days of 200 mg of tafenoquine per day, followed by 200 mg per week; and 3 days of 400 mg of tafenoquine per day, followed by 400 mg per week. Prophylaxis was continued for up to 13 weeks. Of the evaluable subjects (223 of 249 randomized subjects), volunteers who received 400 mg tafenoquine for only 3 days had a protective efficacy of 68% (95% confidence interval [CI], 53%-79%), as compared with placebo recipients; those who received 200 mg per day for 3 days followed by 200 mg per week had a protective efficacy of 86% (95% CI, 73%-93%); and those who received 400 mg for 3 days followed by 400 mg per week had a protective efficacy of 89% (95% CI, 77%-95%). A similar number of volunteers in the 4 treatment groups reported adverse events. Prophylactic regimens of 200 mg or 400 mg of tafenoquine, taken weekly for < or =13 weeks, are highly efficacious in preventing falciparum malaria and are well tolerated.

Pharmacokinetics of an extended-dose halofantrine regimen in patients with malaria and in healthy volunteers.

The pharmacokinetics and tolerance of a 4.5 gm 7-day halofantrine loading dose regimen were evaluated in 10 Thai patients with malaria and in 10 noninfected volunteers. Halofantrine peak plasma concentrations and bioavailability on the first day of treatment were significantly lower in patients with malaria than in healthy volunteers. Halofantrine elimination half-life was significantly shorter in patients with malaria than healthy control subjects (9.5 versus 15.8 days). These data show a distinct effect of acute malaria on the absorption and elimination of the drug. In addition, marked intersubject and intrasubject variability in peak and trough halofantrine levels was observed, indicating variable drug absorption. This dosing regimen was effective and well tolerated, with mild transient diarrhea during the first few days of treatment in both groups. To produce consistently effective drug levels, the currently recommended dosing regimens may be suboptimal. Slow halofantrine elimination raises concern for induction of parasite resistance when the drug is used in endemic areas of the world.

Single-strand conformational polymorphism analysis differentiates Plasmodium falciparum treatment failures from re-infections.

Paired primary and recrudescent Plasmodium falciparum isolates were collected from treatment failures identified during the course of antimalarial drug studies on the Thai-Cambodian border. Ten paired samples were subjected to PCR-restriction fragment length polymorphism (RFLP) and PCR-single-strand conformational polymorphism (PCR-SSCP) analysis of the MSP-2 gene. PCR-SSCP analysis of paired samples demonstrated that each recrudescent isolate was identical to, or a subpopulation of, its matched primary isolate and was distinct from all unrelated isolates. This method represents a field applicable method to distinguish re-infections from treatment failures when antimalarial drug studies are performed in malaria-endemic areas.

Parasight F test compared with the polymerase chain reaction and microscopy for the diagnosis of Plasmodium falciparum malaria in travelers.

Imported malaria is an increasing problem worldwide. A rapid and accurate test for Plasmodium falciparum infection would facilitate the diagnosis of malaria in the returned traveler. The ParaSight F antigen capture assay (dipstick test) is a new diagnostic test for P. falciparum based on detection of circulating histidine-rich protein-2 antigen. We performed a blinded evaluation of this assay compared with microscopy and the polymerase chain reaction (PCR) for the detection of P. falciparum infection in 151 febrile travelers. Compared with the PCR, the dipstick test had a sensitivity of 88% and a specificity of 97%. The ability of the dipstick test to detect P. falciparum was similar with that of microscopy (88% versus 83%) since the species of Plasmodium in 14 of 133 malaria-infected patients could not be determined by microscopy due to low parasite numbers. The dipstick test was 40% sensitive for infections with < 50 parasites/microliter, 89% with 50-100 parasites/microliter, and > or = 93% with > 100 parasites/microliter. Circulating antigen was detectable in 68% of the patients seven days after initiation of treatment and in 27% at day 28. The dipstick test represents a simple and accurate test for the diagnosis of P. falciparum infection in the returned traveler.

Distinguishing Plasmodium falciparum treatment failures from reinfections by restrictions fragment length polymorphism and polymerase chain reaction genotyping.

The inability to distinguish recrudescent Plasmodium falciparum infections (treatment failures) from reinfections (new infections) is an important impediment to the evaluation of antimalarial treatment regimens. Ten paired primary and recrudescent isolates collected near the Thai-Cambodian border were analyzed by restriction fragment length polymorphism (RFLP) and by polymerase chain reaction (PCR) genotyping of the genes encoding the following proteins: circumsporozite (CS) protein, erythrocyte binding antigen (EBA)-175, ring-infected erythrocyte surface antigen (RESA), merozoite surface protein-1 (MSP-1), and MSP-2. Both methods demonstrated that the fingerprint pattern of each recrudescent isolate was identical to or was contained within the pattern of the primary isolate. Each recrudescent isolate was unique when compared with the other nine primary isolates. Typing by PCR was more sensitive for the detection of multiclone infections and could be performed with small volumes of whole blood. The PCR genotyping could be a practical method for distinguishing a recrudescent from a new infection when treatment studies are conducted in areas with active malaria transmission.

Efficacy and tolerance of extended-dose halofantrine for drug-resistant falciparum malaria in Thailand.

New treatments for malaria are urgently needed in areas such as Thailand where highly drug-resistant strains of Plasmodium falciparum are prevalent. Mefloquine is rapidly losing efficacy and conventional doses of halofantrine are infective. We therefore used pharmacokinetic stimulation to design an extended-dose halofantrine regimen and tested it in 26 soldiers stationed along the Thai-Cambodian border. Halofantrine was given after meals as three doses of 500 mg each at 4-hr intervals on the first day, followed by 500 mg a day for six days (total dose 4.5 g). Twenty-six soldiers treated with quinine-tetracycline for seven days (Q7T7) served as controls. There were no significant differences in efficacy between halofantrine and Q7T7 (P > 0.1) as assessed by cure rate (92% versus 85%), mean parasite clearance time (82 hr versus 81 hr), or mean fever clearance time (93 hr versus 99 hr). Halofantrine was better tolerated than Q7T7. The side effects score was lower (2 versus 11; P < 0.001), there were less days on which side effects occurred (2.0 days versus 5.5 days; P < 0.001), and fewer patients had adverse effects on every treatment day (4% versus 42%; P < 0.01). High-dose halofantrine is as effective and better tolerated than quinine-tetracycline for multidrug-resistant falciparum malaria.

Activity of azithromycin as a blood schizonticide against rodent and human plasmodia in vivo.

We compared the efficacy of azithromycin to the clinical antimalarial doxycycline in Plasmodium berghei-infected mice and in P. falciparum-infected Aotus monkeys. When mice were administered drug orally twice a day for three days, the minimum total dose of azithromycin that cured all mice was 768 mg/kg. Doxycycline at a dose of 1,536 mg/kg cured no mice. The efficacy of fast-acting blood schizonticides (quinine, halofantrine, artemisinin) against P. berghei was augmented by azithromycin. In monkey experiments in which there were two animals per experimental group, azithromycin (100 mg/kg/day for seven days) eliminated parasitemia; azithromycin (30 mg/kg/day) initially cleared 99.8-100% of the parasites with recrudescence in the one completely cleared case. Doxycycline (30 mg/kg/day) cleared 100% of the parasites with recrudescence in both cleared cases. Since azithromycin can be clinically administered at a somewhat higher daily dosage than doxycycline, the data suggest that it may be possible to replace drugs of the tetracycline class with azithromycin in combination with fast-acting blood schizonticides for the treatment of P. falciparum infection.

Chloroquine/doxycycline combination versus chloroquine alone, and doxycycline alone for the treatment of Plasmodium falciparum and Plasmodium vivax malaria in northeastern Irian Jaya, Indonesia.

Combination therapy is one method of overcoming the global challenge of drug-resistant Plasmodium falciparum malaria. We conducted a hospital-based 28-day in vivo test comparing chloroquine/doxycycline to chloroquine or doxycycline alone for treating P. falciparum and Plasmodium vivax malaria in Irian Jaya, Indonesia. Eighty-nine patients with uncomplicated falciparum malaria were randomized to standard dose chloroquine (n = 30), doxycycline (100 mg every 12 hours [7 days], n = 20), or chloroquine with doxycycline (n = 39); corresponding numbers for vivax malaria (n = 63) were 23, 16, 24. Endpoints were parasite sensitivity (S) or resistance (RI/RII/RIII). Of the 105 evaluable patients, chloroquine/doxycycline cured (S) 20/22 (90.9% [95% CI 78.9-100%]) patients with P. falciparum malaria; 2/22 (9.1% [0-21%]) were RIII resistant. Doxycycline cured 11/17 (64.7% [42.0-87.4%]) patients, and chloroquine 4/20 (20% [2.5-37.5%]). Against P. vivax, chloroquine/doxycycline cured (S) 12/17 (70.6% [48.9-92.2%]) patients, doxycycline 4/12 (33.3% [6.6-59.9%]), and chloroquine 5/17 (29.4% [7.7-51.1%]). Chloroquine/doxycycline was effective against P. falciparum but only modestly effective against P. vivax. These findings support the use of chloroquine/doxycycline as an inexpensive alternative to mefloquine for treating chloroquine-resistant P. falciparum but not chloroquine-resistant P. vivax in this setting.

Comparison of the ParaSight-F test and the ICT Malaria Pf test with the polymerase chain reaction for the diagnosis of Plasmodium falciparum malaria in travellers.

Rapid and accurate methods are needed for the diagnosis of imported malaria. The ParaSight-F test and the ICT Malaria Pf test are commercially available kits marketed for the diagnosis of Plasmodium falciparum malaria. Both tests are antigen-capture assays based on the detection of P. falciparum histidine-rich protein 2 in peripheral blood. Using microscopy and a polymerase chain reaction (PCR)-based method as reference standards, we performed a 'blinded' comparison of these assays for the detection of P. falciparum infection in 200 febrile travellers returning from malaria-endemic areas. As determined by PCR and microscopy, 148 travellers had malaria and, of these patients, 54.7% (81/148) were infected with P. vivax only, 31.1% (46/148) with P. falciparum only, 9.5% (14/148) with P. ovale, 0.7% (1/148) with P. malariae, and 4.1% (6/148) had mixed infections. Compared to PCR, the ParaSight-F and ICT Malaria Pf tests had initial sensitivities of 94% and 90% and specificities of 95% and 97%, respectively, for the detection of P. falciparum malaria. When discrepant samples were retested with day 0 and day 1 bloods, the sensitivities improved to 96% and 94%, respectively. The 2 remaining false negative results with the Para-Sight-F test and 2 of the 3 false negative results with the ICT Malaria Pf test occurred in samples with < 100 parasites/microL. The performance of these kits was not significantly different (P = 0.75) and both are simple, rapid, and accurate tests for the detection of P. falciparum infection in the returned traveller.

[Immunopathological study of bullous pemphigoid, cicatricial pemphigoid and herpes gestationis]. / Etude immunopathologique de la pemphigoïde bulleuse, de la pemphigoïde cicatricielle et de l'herpes gestationis.

The entity of the Dühring-Brocq's disease (11, 12, 20) has be cut off by the immunofluorescence (7, 39, 40). We have studied three of the diseases which originally were included in this description: bullous pemphigoid (BP), cicacial pemphigoid (CP) and herpes gestationis (HG). This work is at the same time prospective and retrospective. The linear IgA dermatosis are excluded (17).

[Immunofluorescence and immunoperoxidase: a comparison for sensitivity in cutaneous immunopathology (author's transl)]. / Immunofluorescence et immunoperoxydase: comparaison de la sensibilité en immunopathologie cutanée.

A comparative study of the sensitivities of the immunofluorescence (IF) and immunoperoxydase (IPo) techniques was undertaken. The material used was biopsies of various skin lesions and especially pemphigus, bullous pemphigoid, lupus erythematosus and dermatitis herpetiformis. Direct and indirect methods were performed for the detection of fixed immunoglobulins and complement deposits. With large deposits, immunoperoxydase and immunofluorescence show an equal sensibility and the labeling obtained with IPo is never more intensive than the labeling obtained with IF. In contrast, with small deposits, IPo was less sensitive than IF and appears negative in the majority of the cases and especially in dermatitis herpetiformis. These results are confirmed in using increasing dilutions of conjugates and can be explained by the difficulty in doing the observation of small positive deposits with IPo.

Achieving compliance with influenza immunization of medical house staff and students. A randomized controlled trial.

OBJECTIVE: To determine the optimal method to increase influenza immunization rates of medical house staff and students. DESIGN: Prospective randomized trial and cross-sectional survey. STUDY GROUP: Four hundred forty-two internal medicine, obstetrics-gynecology, and general surgery residents and junior medical students. MEASUREMENTS: The four interventions employed were (1) an educational memorandum outlining vaccine indications sent to all study group members, (2) a personal letter mailed to a random sample of half of the remaining unimmunized persons, (3) a telephone call to half of the unimmunized letter recipients, and (4) vaccine offered directly to the remaining unimmunized persons in clinics and conferences. In addition, a questionnaire was administered to all persons requesting or offered vaccine. MAIN RESULTS: During the 3 weeks after the memorandum, 87 (20%) of 442 persons were immunized. Five weeks after the letter, 61 (34%) of persons receiving a letter and 30 (17%) of the no-letter controls (P = .0005) had been immunized. After the telephone call, there was a statistically insignificant trend toward increased compliance. In clinics and conferences, 90% of persons reached were immunized and 10% refused, largely extinguishing the effect of prior interventions. At completion of the study, 275 (62%) of 442 participants were immunized, 29 (7%) refused, and 138 (31%) were not reached. Questionnaire results revealed that only 32% had ever been previously immunized against influenza, yet 70% stated that they had worked despite having influenzalike symptoms. CONCLUSION: A high rate of immunization of house staff and medical students can be achieved most effectively by offering vaccine in clinics and conferences. Continued education about influenza immunization is necessary for physicians and medical students.

Preparation of whole rabbit knee joints for microscopic examination.

A paraffin embedding method to prepare whole rabbit knee joints for histological examination is described. This method provides good quality microscopic sections thin enough for the study of cellular detail and does not require prolonged processing. When examining pathologic changes in experimental arthritis, it is advantageous to be able to examine the intact joint with the structural relations of the joint components preserved. Sections of the whole joint provide numerous areas where bone, cartilage and synovium are contiguous for examination. Having obtained poor results using methods recommended for small bony specimens, we modified several existing procedures to obtain a reliable method for preparing excellent microscopic sections of the whole rabbit knee joint.

Expression of blood group antigens by cultured human epidermal cells used as allografts.

The expression of blood-group antigens was studied on human epidermal cultures used as allografts in 13 non-immunosuppressed patients treated for leg ulcers. The study was carried out using monoclonal antibodies to A and B antigens by an indirect immunofluorescence technique. Blood-group antigens are weakly expressed on the suprabasal layers of the cultured epidermal sheets. After grafting, the donor's blood-group antigens were detected on a few cells of the suprabasal layers. Furthermore, scattered keratinocytes as well as acrosyringia were found to express the recipient's blood-group antigens.

Determination of failure of treatment of plasmodium falciparum infection by using polymerase chain reaction single-strand conformational polymorphism fingerprinting.

The inability to distinguish failures of treatment of Plasmodium falciparum infection from new infections is an important impediment to the evaluation of antimalarial drugs. On the basis of a pilot study utilizing polymerase chain reaction (PCR) single-strand conformational polymorphism (SSCP) analysis to genotype P. falciparum isolates, we sought to confirm that PCR SSCP analysis could reliably distinguish infections for which treatment failed from unrelated infections with a sample size adequate to estimate the accuracy of this technique. PCR SSCP analysis of the MSP-1, MSP-2, and GLURP genes was performed on 72 paired isolates recovered from 36 individuals for whom treatment failed in Thailand. In every case (100% [95% confidence interval (CI), 90%-100%]), the PCR SSCP pattern of the recrudescent isolates matched that of the primary isolate. We determined whether PCR SSCP analysis could separate unrelated infections by comparing each recrudescent isolate with each of the unrelated primary isolates. Of 1,260 comparisons, 1,258 (99.8% [95% CI, 99.4%-100%]) were unique. The results indicate that PCR SSCP analysis can be used to differentiate infections for which treatment failed from reinfections.

Semiologic value of C1q and C4 cutaneous deposits. An immunofluorescent study.

One hundred twenty skin biopsies from patients with different skin diseases were found to be positive for C3 cutaneous staining by immunofluorescence study. By the direct immunofluorescence method, we looked for C1q and C4 and immunoglobulin deposits in all those biopsies. C1q and/or C4 were only found in dermatoses with a recognised humoral immunologic mechanism; in some cases C1q and/or C4 deposits were found in the absence of immunoglobulins. The results showed that identification of C1q and C4 is important in routine immunopathologic studies, and provide interesting data of diagnostic value.

Lichen planus and chronic graft-versus-host reaction. In situ identification of immunocompetent cell phenotypes.

The purpose of the present study was to examine the phenotype of the cutaneous immunocompetent cells in lichen planus and chronic graft versus host (GVH) reaction infiltrates, by the use of monoclonal antibodies directed against T cell populations and Langerhans cells. Our results in lichen planus suggest an immunological reaction similar to the delayed hypersensitivity reaction, including all the immunocompetent cell subpopulations, with a first stage of antigenic information by Langerhans cells (OKT6+, BL6+, HLA-DR+) and helper cells, and a second stage mediated by suppressor/cytotoxic cells. The results from the study of GVH reaction also suggest an effect mediated by suppressor/cytotoxic cells (OKT3+, OKT4-, OKT8+, HLA-DR+). Our results favour the existence of a lymphocytotoxic process in lichen planus and chronic GVH reaction.

Antigenic thymus-epidermis relationships. Reactivity of a panel of anti-thymic cell monoclonal antibodies on human keratinocytes and Langerhans cells.

We have investigated on human skin the reactivity of a panel of 42 anti-thymus monoclonal antibodies (MCA) supplied by the Third International Workshop and Conference on Human Leucocyte Differentiation Antigens, Oxford, 1986. MCA of the first cluster of differentiation (CD1) define a group of surface molecules expressed by cortical thymocytes. Some of them (OKT6, M241 and Na1/34) have been shown to react in normal human skin with the epidermal Langerhans cells (LC). Twenty-two CD1 MCA were investigated in the present study. On normal human skin, 13 MCA reacted with LC in situ. This result suggests and confirms the heterogeneity of CD1 MCA. Recently, some of them were shown to recognize biochemically different molecules and/or epitopes of thymocytes. In addition, 20 anti-thymic epithelium MCA were tested on human skin. The MCA which only reacted with the thymic epithelial cell network (except Hassall's corpuscles) decorated only the epidermal basal cell layer. The MCA which reacted with all the thymic epithelial cells (including Hassall's corpuscles) decorated all the epidermal cell layers. These results confirm the heterogeneity of the thymic epithelial microenvironment and underline the antigenic similarities between the thymic epithelial structures and the different epidermal cell layers. The existence of bone-marrow-derived CD1-positive cells (thymocytes or LC) in an epithelial cell network (the thymus and the epidermis) focus the speculation around the immunological role of the epidermal basal cell layer in the T cell education and the exact lineage of the epidermal LC.

Randomised placebo-controlled trial of primaquine for prophylaxis of falciparum and vivax malaria.

Drug resistance has made malaria prevention difficult and the new agents are too expensive for widespread use. Primaquine, an established drug for treatment, is potentially useful for prevention. Malaria prophylaxis with primaquine was evaluated in Irian Jaya during one year in Javanese men who were not deficient in glucose-6-phosphate dehydrogenase (G-6-PD). 126 volunteers were randomised to receive 0.5 mg/kg primaquine base or placebo daily (double-blinded), or 300 mg chloroquine base weekly (open). The protective efficacy of primaquine relative to placebo was 94.5% (95% confidence interval 57-99) for Plasmodium falciparum and 90.4% (95% CI 58-98) for P vivax. Attack rates for either parasite did not differ significantly between the chloroquine and placebo groups. Incidence density of physical complaints not associated with parasitaemia was low (17-18 complaints/person-year) and was about the same in all groups except for cough, which was increased in the primaquine group. Complete blood counts were normal and no evidence of hepatic or renal dysfunction was found with primaquine. However, at 50 weeks the primaquine group had a mean methaemoglobin of 5.8% (range 1.4-13%), which declined by half within 7 days of ending prophylaxis. When used daily for one year by men with normal G-6-PD activity, primaquine was well tolerated and effective for prevention of malaria.