S A Stockwell | PubMed Health

PubMed2001

Centipede envenomation.

Five episodes of envenomation by centipedes in 2 patients are reported. These arthropods are fast-moving, frightening in appearance to some, and may display aggressive behavior. However, stings from these centipedes, like most found worldwide, caused no serious morbidity or mortality. Common effects included intense local pain, erythema, induration, and necrosis, as well as mild constitutional symptoms. All resolved without sequelae. Treatment included pain control, wound care, and tetanus immunization.

Adult↗

PubMed1999

The fluorescence of scorpions and cataractogenesis.

BACKGROUND: Protein cross-linking and fluorescence are widely recognized markers of oxidative aging in human proteins. Oxidative protein aging is a combinatorial process in which diversity arises from the heterogeneity of the targets and is amplified by the nonselective nature of the reactants. The cross-links themselves defy analysis because they are generally embedded in a covalent matrix. Arthropods rely upon oxidative cross-linking in the hardening of the cuticle - a process known as sclerotization. Among arthropods, scorpions are noteworthy in that the process of sclerotization is accompanied by the buildup of strong visible fluorescence. To date, the nature of the fluorescent species has remained a mystery. RESULTS: We have identified one of the soluble fluorescent components of the scorpions Centuroides vittatus and Pandinus imperator as beta-carboline - a tryptophan derivative that has previously been identified by hydrolysis and oxidation of lens protein. We have also shown that beta-carboline-3-carboxylic acid is released from both scorpion exuvia (the shed cuticle) and human cataracts upon hydrolysis, suggesting that the protein-bound beta-carboline and free beta-carboline have common chemical origins. CONCLUSIONS: Cataractogenesis and cuticular sclerotization are disparate oxidative processes - the former is collateral and the latter is constitutive. The common formation of beta-carbolines shows that similar patterns of reactivity are operative. These fundamental mechanisms provide predictive insight into the consequences of human protein aging.

Animals↗

PubMed1995

Field evaluation of four repellents against Leptoconops americanus (Diptera: Ceratopogonidae) biting midges.

Four repellents, deet, AI3-37220, AI3-35765, and CIC-4, prepared as 12.5% ethanol solutions, were evaluated against biting midges on Stansbury Islands, UT. Leptoconops americanus Carter was the only species that was biting human volunteers during the study. This species bit primarily on the ears at rates up to 840 bites per hour. All four repellents significantly reduced the number of bites on treated volunteers. AI3-37220 consistently provided the longest period of protection, giving 97 and 74% protection at 4 and 8 h, respectively. In a direct statistical comparison, AI3-37220 significantly outperformed deet. CIC-4 and AI3-35765 were the least effective repellents, providing 45-47% protection 8 h after application.

Animals↗