A general swimming response in exhausted obligate swimming fish.

Marine organisms normally swim at elevated speeds relative to cruising speeds only during strenuous activity, such as predation or escape. We measured swimming speeds of 29 ram ventilating sharks from 10 species and of three Atlantic bluefin tunas immediately after exhaustive exercise (fighting a capture by hook-and-line) and unexpectedly found all individuals exhibited a uniform mechanical response, with swimming speed initially two times higher than the cruising speeds reached approximately 6 h later. We hypothesized that elevated swimming behaviour is a means to increase energetic demand and drive the removal of lactate accumulated during capture via oxidation. To explore this hypothesis, we estimated the mechanical work that must have been spent by an animal to elevate its swim speed and then showed that the amount of lactate that could have been oxidized to fuel it comprises a significant portion of the amount of lactate normally observed in fishes after exhaustive exercise. An estimate for the full energetic cost of the catch-and-release event ensued.

American cutaneous leishmaniasis.

We present 3 cases of American cutaneous leishmaniasis occurring in soldiers of a unit of US Army Rangers who parachuted into the jungles of Panama. Shortly after returning to the United States, these 3 soldiers each developed a crusted, indurated papule, which slowly enlarged during the following 6 weeks. Routine microscopy of skin biopsies revealed a dermal granulomatous inflammation and a predominantly lymphoid infiltrate. Numerous histiocytes contained small oval organisms with bar-shaped paranuclear kinetoplasts, morphologically consistent with leishmanial parasites. Cultures grew Leishmaniasis brasiliensis, subspecies panamensis. The soldiers were treated with intravenous pentavalent antimonial therapy daily for 20 days with good clinical improvement. Epidemics of leishmaniasis occur periodically in tropical regions of the world, and leishmaniasis has emerged in new settings, for example, as an acquired immunodeficiency syndrome-associated opportunistic infection. With an increasingly mobile society, it is important to be familiar with the clinical and histopathologic appearance of conditions such as leishmaniasis, which are common in tropical and subtropical regions and are increasingly significant in other regions of the world.

Shear bond strength of resin to acid/pumice-microabraded enamel.

The effect of enamel microabrasion techniques consisting of either 18% hydrochloric acid in pumice or a commercially available abrasive/10% hydrochloric acid mixture, PREMA, on composite/enamel shear bond strengths was investigated. Sixty extracted third molars had the bonding surface flattened and were divided into six treatment groups (n=10) with the enamel treated prior to bonding as follows: Group 1-- untreated; Group 2--37% phosphoric acid etched for 30 seconds; Group 3--18% hydrochloric acid/pumice mixture applied for five 20-second treatments; Group 4--similar to Group 3 with additional 37% phosphoric acid etch; Group 5--treated with PREMA compound applied for five 20-second treatments; Group 6--similar to Group 5 treatment with additional 37% phosphoric acid. Herculite XR composite resin was then bonded to all samples using a VLC unit. Samples were tested in shear, and fractured enamel surfaces were evaluated using light microscopy to determine the enamel-to-resin failures. Resin bond strengths to microabraded and H3PO4-etched enamel were similar to bond strengths of untreated H3PO4-etched enamel and were significantly better than bond strengths to PREMA-treated or unetched enamel.