Millimeter-scale topography facilitates coral larval settlement in wave-driven oscillatory flow.

Larval settlement in wave-dominated, nearshore environments is the most critical life stage for a vast array of marine invertebrates, yet it is poorly understood and virtually impossible to observe in situ. Using a custom-built flume tank that mimics the oscillatory fluid flow over a shallow coral reef, we isolated the effect of millimeter-scale benthic topography and showed that it increases the settlement of slow-swimming coral larvae by an order of magnitude relative to flat substrates. Particle tracking velocimetry of flow fields revealed that millimeter-scale ridges introduced regions of flow recirculation that redirected larvae toward the substrate surface and decreased the local fluid speed, effectively increasing the window of time for larvae to settle.

Effect of systemic and intrathecal morphine in a rat model of postoperative pain.

Background: To learn more about persistent pain after an incision, a rat model for postoperative pain has been developed. To further evaluate this model, the authors examined the effect of intrathecal (IT) and subcutaneous (SC) morphine, effective for postoperative pain relief in patients, on pain behaviors immediately after surgery and 1 day after surgery.

Methods: Rats were anesthetized with halothane, and a 1-cm incision was made in the plantar aspect of the foot and closed.

Carcinogen-induced tissue vitamin A depletion. Potential protective advantages of beta-carotene.

Exposure to benzopyrene, an enzyme-inducing PAH carcinogen, promotes vitamin A depletion in exposed tissues. This effect is evident while on a vitamin A sufficient diet and without a decline in serum retinol. The finding of local tissue vitamin depletion without systemic depletion may have considerable implications in maintaining tissue health.

Exposure to the carcinogen benzopyrene depletes tissue vitamin A: beta-carotene prevents depletion.

Evidence in humans and laboratory animals supports a cancer-protective effect of vitamin A, but the mechanism remains unclear. While vitamin A deficiency causes squamous metaplasia, and lung cancer patients have lower vitamin A status, their serum vitamin A levels are not indicative of deficiency. We hypothesize that local enzymatic degradation of vitamin A can be induced by exposure to carcinogens such as benzopyrene found in cigarette smoke.