A prospective, multicenter study of bovine pericardium membrane with cancellous particulate allograft for localized alveolar ridge augmentation.

Resorption of the alveolar ridge may lead to ridge deformities that make dental implant placement difficult or impossible. Augmentation of the alveolar ridge may restore appropriate ridge form to allow implant placement. Forty-four patients with edentulous spaces completed this multicenter prospective trial to clinically and radiographically evaluate the efficacy of a bovine pericardium membrane and a particulate mineralized cancellous bone allograft in promoting lateral ridge augmentation. Overall, 38 of 44 patients (86.4%) were able to receive dental implants in the appropriate restoratively driven position 6 months after ridge augmentation. The mean gain in clinical ridge width after augmentation was 2.61 mm, while radiographically the mean gain in ridge width was 1.65 mm at a level 3 mm apical to the bony crest and 1.93 mm at a level 6 mm apical to the crest. On average, approximately 50% of the graft material added horizontally during surgery was displaced or resorbed during healing. Histomorphometric evaluation of cores taken from the augmented ridge at 6 months revealed that approximately 58% of the tissue volume was vital bone, with 12% residual allograft particles and 30% nonmineralized tissue.

Melatonin and locomotor activity in the fiddler crab Uca pugilator.

The influence of melatonin on locomotor activity levels was measured in the fiddler crab Uca pugilator. First, activity in untreated, laboratory-acclimated crabs was measured over 48 hours in a 12L:12D photoperiod; this study showed a nocturnal increase in activity. In eyestalk-ablated crabs, overall activity was significantly reduced, and no significant activity pattern occurred. Next, crabs were injected with melatonin or saline (controls) at various times during the 12L:12D photoperiod (0900h, 1200h, and twice at 2100h; each trial was separated by 3-4 days) and monitored for 3 hr post-injection. Control crabs had low activity during early photophase, high at mid-photophase, increasing activity during the first scotophase trial, and decreasing activity during the second scotophase trial. Melatonin had no significant influence on activity when injected during the early-photophase activity trough or early-scotophase activity decline, but significantly increased activity when injected during the mid-photophase activity peak and early-scotophase activity incline. Next, crabs were injected during an early scotophase activity trough and monitored throughout the twelve-hour scotophase. Melatonin did not increase activity until the mid-scotophase activity increase, approximately 6 hours later, showing that the pharmacological dosage persisted in the crabs' systems and had later effects during the incline and peak of activity but not the trough. Eyestalk-ablated crabs were injected with melatonin or saline during early photo- and scotophase. Melatonin significantly increased activity in the photophase but not the scotophase trial, indicating that the responsiveness to melatonin continues following eyestalk removal, but the timing may not match that of intact crabs. Melatonin may be involved in the transmission of environmental timing information from the eyestalks to locomotor centers in U. pugilator.