ABSTRACT
Testing Plasmodium vivax antimicrobial sensitivity is limited to ex vivo schizont maturation assays, which preclude determining the IC50s of delayed action antimalarials such as doxycycline. Using Plasmodium cynomolgi as a model for P. vivax, we determined the physiologically significant delayed death effect induced by doxycycline [IC50(96 h), 1,401 ± 607 nM]. As expected, IC50(96 h) to chloroquine (20.4 nM), piperaquine (12.6 µM), and tafenoquine (1,424 nM) were not affected by extended exposure.
Subject(s)
Aminoquinolines , Antimalarials , Doxycycline , Piperazines , Plasmodium cynomolgi , Plasmodium vivax , Doxycycline/pharmacology , Antimalarials/pharmacology , Aminoquinolines/pharmacology , Plasmodium vivax/drug effects , Plasmodium cynomolgi/drug effects , Chloroquine/pharmacology , Animals , Malaria, Vivax/drug therapy , Malaria, Vivax/parasitology , Quinolines/pharmacology , Inhibitory Concentration 50 , Humans , Parasitic Sensitivity TestsABSTRACT
The lack of a long-term in vitro culture method has severely restricted the study of Plasmodium vivax, in part because it limits genetic manipulation and reverse genetics. We used the recently optimized Plasmodium cynomolgi Berok in vitro culture model to investigate the putative P. vivax drug resistance marker MDR1 Y976F. Introduction of this mutation using clustered regularly interspaced short palindromic repeats-CRISPR-associated protein 9 (CRISPR-Cas9) increased sensitivity to mefloquine, but had no significant effect on sensitivity to chloroquine, amodiaquine, piperaquine, and artesunate. To our knowledge, this is the first reported use of CRISPR-Cas9 in P. cynomolgi, and the first reported integrative genetic manipulation of this species.
Subject(s)
Antimalarials , Plasmodium cynomolgi , Mefloquine/pharmacology , Antimalarials/pharmacology , Chloroquine/pharmacology , Plasmodium vivax/genetics , Drug Resistance/genetics , Drug Resistance, Multiple/genetics , Plasmodium falciparumABSTRACT
The absence of a routine continuous in vitro cultivation method for Plasmodium vivax, an important globally distributed parasite species causing malaria in humans, has restricted investigations to field and clinical sampling. Such a method has recently been developed for the Berok strain of P. cynomolgi, a parasite of macaques that has long been used as a model for P. vivax, as these two parasites are nearly indistinguishable biologically and are genetically closely related. The availability of the P. cynomolgi Berok in routine continuous culture provides for the first time an opportunity to conduct a plethora of functional studies. However, the initial cultivation protocol proved unsuited for investigations requiring extended cultivation times, such as reverse genetics and drug resistance. Here we have addressed some of the critical obstacles to this, and we propose a set of modifications that help overcome them.
Subject(s)
Malaria, Vivax , Malaria , Parasites , Plasmodium cynomolgi , Animals , Macaca/parasitology , Malaria/parasitology , Malaria, Vivax/parasitology , Plasmodium vivaxABSTRACT
We report a case of massive tongue engorgement associated with the placement of a laryngeal tube device (King Airway-LTS-D EMS). Our patient developed isolated, massive lingual swelling approximately 3 hours after the out-of-hospital placement of a laryngeal tube. Swelling resolved 2 days later in the ICU after fiberoptic-guided exchange of the laryngeal tube for an endotracheal tube. It is most likely that the observed swelling was due to obstruction of venous drainage from the tongue by the oropharyngeal balloon. Other etiologies for lingual swelling such as angioedema cannot be definitively ruled out but are less likely to have caused the patient's tongue engorgement.
