Ontogenetic Changes in Nutrients and Stoichiometry in the Invasive Mosquito, Aedes albopictus (Diptera: Culicidae).

A variety of physiological, morphological, and behavioral changes occur throughout the life cycle of mosquitoes, which can be correlated with a shift from the aquatic to terrestrial environment. Aedes albopictus Skuse is an abundant invasive species from Asia that was introduced into the Americas in the 1980's and is responsible for transmitting several important human disease-causing pathogens. How physiological and anatomical changes within each instar and throughout the developmental stages are related to changes in carbon (C) and nitrogen (N) levels are an unexplored area of mosquito ecology. We hypothesized that these changes as well as stoichiometry (C:N) would vary with instar stage and larval diet. Cohorts of larvae were grown in three different diets: animal only (crickets), plant only (red maple leaves), and a mixture containing both types. Larval instars (1st-4th), pupae, and adults were raised in each diet and were separately analyzed for nutrient content (%C, %N) and stoichiometry (C:N). Significant changes in nutrient values occurred across the life cycle, with C:N values being lower in early instars versus adults or pupae, especially in animal only or mixed diets; few differences were detected in %C or %N across ontogeny. This knowledge may lead to a better understanding of mosquito ecology and pathogen transmission.

Time to failure of arterial shunts in a pig hemorrhagic shock model.

Temporary vascular shunts (TVSs) are relied on frequently in the current military theater. Details of their physiology and outcome are of increasing interest and needed to further define their place in the management of trauma. This study was conducted using a porcine hemorrhagic shock model and aimed to 1) establish the time to failure of short, proximally placed vascular shunts; and 2) examine histological changes in the shunted artery. The external iliac artery of male pigs was transected and a straight shunt secured in place. Hemorrhagic shock was then induced by rapidly removing 40 per cent of blood volume and maintaining severe hypotension for 40 minutes before resuscitation. Animals were observed for up to 6 days for limb function as well as overall physiological status. At the conclusion of the experiment, status of the shunt and adjacent artery was evaluated by an independent pathologist. The presence of thrombi and inflammation within the proximal and distal artery was graded. Among the 10 animals tested, nine subjects survived the initial surgery. All shunts remained patent with mean time of 4.2±1.2 days of observation. Three-position histological analysis of the connected arterial tissues revealed minimal acute inflammation and minimal or thrombus. The results suggest that TVSs in proximal arteries remain functional for at least 48 to 72 hours in proximal arteries even without anticoagulation in the setting of brief hemorrhagic shock. This knowledge may aid combat evacuation patterns.

Central giant cell lesion.

A classic case of central giant cell lesion (CGCL) is presented with emphasis on clinical, radiologic, and histologic features. The differential is discussed including peripheral giant cell granuloma, brown tumor of hyperparathyroidism, and giant cell tumor of bone. The molecular pathway of osteoclastogenesis is selectively reviewed and applied to suggest possible etiologies of the giant cell lesions. CGCL syndromes and treatment are also discussed.