The separation and analysis of symmetric and asymmetric dimethylarginine and other hydrophilic isobaric compounds using aqueous normal phase chromatography.

Two biologically important compounds with clinical relevance, asymmetric dimethylarginine and symmetric dimethylarginine, are analyzed using aqueous normal phase chromatography on silica hydride-based columns. Two different stationary phases were tested, a commercially available Diamond Hydride™ and a 2-acrylamido-2-methylpropane sulfonic acid experimental column. Two types of analytical protocols were investigated: analysis of the compounds when separation was achieved and analysis of the compounds with partial chromatographic separation.

Evolution of repellent tolerances in representative arthropods.

Eight commercial insect repellents were tested against Ornithodoros parkeri (Acari: Argasidae), Dermacentor variabilis (Acari: Ixodidae), Aedes aegypti (Diptera: Culicidae), and Xenopsylla cheopis (Siphonaptera: Pulicidae). Patterns of tolerance to the test materials were distinctive for each test species. Levels of tolerance were coded as character state 0 (sensitive), 1 (intermediate), or 2 (tolerant) and mapped on a cladogram reflecting the accepted classification of the test species.

U.S. Army soldiers' perceptions of arthropod pests and their effects on military missions.

A survey was conducted to determine the effects of biting and stinging arthropods on military personnel, operations, and training. Nearly 70% of respondents reported experiencing problems attributable to arthropods. Arthropods obstructed movement and field position, prevented concealment and cover, disrupted maneuvers, and caused panic.

Evaluation of the laboratory rabbit model for screening topical mosquito repellents.

The laboratory rabbit was evaluated as a model for screening topical mosquito repellents, using data obtained in tests of deet (N,N-diethyl-3-methylbenzamide) against Aedes aegypti on humans and rabbits. Host-specific differences in the action of the test material were quantified by multiple regression analysis. The test material was less effective but more persistent in tests on rabbits, and responses of the mosquito test population were more variable.

Evaluation of controlled-release mosquito repellent formulations.

Eight polymer and 9 microcapsule formulations of deet were tested on laboratory rabbits against Aedes aegypti and Anopheles albimanus. Several formulations were significantly more effective than simple (unformulated) deet at the same strength for periods up to 24 h. Best results were obtained with a polymer formulation containing a high molecular weight fatty acid and 3 microcapsule formulations containing lanolin, gum arabic, gelatin, tannic acid, stearic acid, polypropylene glycol, water, and a commercial lotion in the microcapsule and carrier fractions.

Myiasis in a wounded soldier returning from Panama.

An imported case of traumatic myiasis occurred in a soldier wounded during military action in Panama in December 1989 and evacuated to Brooke Army Medical Center, Fort Sam Houston, Texas. At the medical center, five larvae were removed from the scalp wound, reared to the adult stage, and identified as Cochliomyia hominivorax (Coquerel). Though this was the only reported case of wound myiasis of the 254 servicemen evacuated for medical treatment, this incident indicates a potential mechanism for the reintroduction of C.

Attraction of mosquitoes to diethyl methylbenzamide and ethyl hexanediol.

Studies by prior workers have shown that insect repellents can act as attractants when present as low concentrations, deposits or residues. In the present study deet and ethyl hexanediol were tested in 2-fold serial doses from 1.9 X 10(-9) to 1.

Mutagenic potential of permethrin in the Drosophila melanogaster (Diptera: Drosophilidae) sex-linked recessive lethal test.

When permethrin was tested for mutagenicity in Drosophila melanogaster Meigen with the sex-linked recessive lethal test, it was nonmutagenic under conditions of this study. The frequencies of spontaneous mutation for permethrin and the negative control were 0.135% and 0.

Laboratory evaluation of controlled-release insect repellent formulations.

Seven microcapsule formulations and two polymer formulations of deet were tested on white rabbits for their repellency against the mosquito, Aedes aegypti. Two microcapsule formulations and one polymer formulation provided more than 80% protection for 12 hours. Results demonstrated that the protection period of deet can be extended through controlled-release techniques.

Mathematical models of the effectiveness and persistence of mosquito repellents.

Two models of the effectiveness and persistence of mosquito repellents on the skin were developed from published functions and data. The probit plane model, Y = a + b1X1 + b2X2, relates the response (Y, in probits) of the mosquito test population to the log dose (X1) of repellent applied and the test period, or elapsed time from the time of application (X2). The exponential decay model, Z = X1 + (b2/b1)X2, estimates the repellent residue (log-1 Z) from X1 and X2.