| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
The influence of several factors on parasite growth and 50% inhibitory concentration (IC50) for chloroquine was assessed. Most isolates stored at 4°C up to 72 hours grew when they were subsequently cultivated. However, parasite viability sharply decreased from 24 hours, and the mean chloroquine IC50 decreased significantly (P < 0.05). There was no evidence for selection of pre-culture populations due to storage alone. The time point when 3H-hypoxanthine was added (0 versus 18 hours) had no effect on the IC50 during the 42-hour incubation, but was associated with a lower IC50 when 3H-hypoxanthine was added after the initial 42-hour incubation during the 72-hour incubation. An increase in 3H-hypoxanthine incorporation and chloroquine IC50 was observed as the hematocrit was increased from 1.0% to 2.5%. For the same isolates, chloroquine IC50 values were generally similar when the initial parasitemia was between 0.1% and 0.5% but increased at higher (>0.75%) parasitemias. Based on these results, we recommend immediate cultivation after blood collection, a 42-hour incubation period with the addition of 3H-hypoxanthine at the beginning of incubation, a 1.5% hematocrit, and an initial parasitemia 0.1-0.5%. Further studies on serum substitutes, gas mixture, and comparison of isotopic and non-isotopic assays are needed to establish a standardized in vitro assay protocol.
Received July 13, 2003. Accepted for publication January 8, 2004.
Acknowledgments: I thank Sister Marie-Solange Oko, the personnel of Nlongkak Catholic missionary dispensary, and Delphine Ngo Ndombol for their aid in recruiting patients.
Financial support: This study was supported by the French Ministry of Research (Program PAL+).
Author’s address: Leonardo K. Basco, Unité de Recherche Paludologie Afro-Tropicale, Institut de Recherche pour le Développement, Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, BP 288, Yaounde, Cameroon, Telephone: 237-2-232-232 Fax: 237-2-230-061, E-mails: lkbasco{at}yahoo.fr and Leonardo.Basco{at}ibaic.u-psud.fr.
This article has been cited by other articles:
|
|
 |
|
  S. Houze, A. Munier, X. Paoletti, H. Kaddouri, P. Ringwald, and J. Le Bras Shelf Life of Predosed Plates Containing Mefloquine, Artemisinin, Dihydroartemisinin, and Artesunate as Used for In Vitro Plasmodium falciparum Susceptibility Assessment J. Clin. Microbiol., August 1, 2007; 45(8): 2734 - 2736. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. OSORIO, C. MURILLO, S. APONTE, V. MAYAGAYA, C. SCHEURER, R. BRUN, H. MATILE, and S. WITTLIN IN VITRO SUSCEPTIBILITY OF P. FALCIPARUM POPULATIONS FROM COLOMBIA AND TANZANIA TO A NEW SYNTHETIC PEROXIDE (OZ277) Am J Trop Med Hyg, June 1, 2007; 76(6): 1024 - 1026. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. J. Bacon, C. Latour, C. Lucas, O. Colina, P. Ringwald, and S. Picot Comparison of a SYBR Green I-Based Assay with a Histidine-Rich Protein II Enzyme-Linked Immunosorbent Assay for In Vitro Antimalarial Drug Efficacy Testing and Application to Clinical Isolates Antimicrob. Agents Chemother., April 1, 2007; 51(4): 1172 - 1178. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. K. BASCO MOLECULAR EPIDEMIOLOGY OF MALARIA IN CAMEROON. XXIII. EXPERIMENTAL STUDIES ON SERUM SUBSTITUTES AND ALTERNATIVE CULTURE MEDIA FOR IN VITRO DRUG SENSITIVITY ASSAYS USING CLINICAL ISOLATES OF PLASMODIUM FALCIPARUM Am J Trop Med Hyg, November 1, 2006; 75(5): 777 - 782. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
