Experimental studies in the survival of venous island flaps without arterial inflow

The authors have studied the effects of various circulatory settings on flap survival. The dog model was used to study the survival of venous flaps without arterial inflow both as island and free flaps. Venous flaps were compared with arterial flaps without venous outflow and standard island flaps with arterial inflow and venous outflow. Attempts were made to study their vascular morphology and blood gas changes. The venous flaps without arterial inflow survived with normal hair growth and wound healing, as did the standard island flaps. These observations suggest that capillary diffusion can occur without the continuous flow of blood through a capillary. Several possible mechanisms to explain survival of the venous flaps without arterial inflow were discussed. These observations could be important in providing an animal model to study microcirculation and a possible new area for microsurgical transfer of a skin flap.

Vascular island skin-flap tolerance to warm ischemia: an analysis by perfusion fluorometry

Fiberoptic perfusion fluorometry and assessment of ultimate viability were used to analyze the tolerance to warm ischemia of rat vascular island skin flaps. Both acute flaps and flaps raised 24 hours previously and then reraised were subjected to 0 (control), 6, 8, 10, and 12 hours of vascular pedicle clamping. Following clamp release, serial fluorometry documented the progressive delay in effective reflow resulting from extended periods of ischemia. Fluorometry, furthermore , suggested that flaps constructed 24 hours previously had an improved hemodynamic status with a significantly reduced period of poor reflow following clamp release. The improved hemodynamics were associated with increased viability, confirming the increased tolerance of 24-hour-old flaps to warm ischemia.

An improved one-stage total ear reconstruction procedure

Based on anatomic studies of the postauricular cutaneous circulation, a modified single-stage total ear reconstruction procedure has been presented. The operation consists of using a large, superthin, well-vascularized, and well-innervated skin flap to cover the anterior surface of the auricular framework carved from costal cartilage, the posterior surface of which is covered by a subcutaneous tissue flap and then skin grafted. Improvements in the makeup and carving of the framework have been made and described. This method has been used to treat 15 cases of anotia, all with satisfactory results.

The screening of beta-lactamase inhibitors: inhibition by fatty acids produced by bacteria

An active principle inhibiting beta-lactamases, which was found in the culture of a bacillus strain was a mixture of known C14-C17 fatty acids. The mixture was separated into five components by high-performance liquid chromatography. Among these components, 12-methyltetradecanoic acid showed the strongest activity (I50: 20-146 microM). The anteiso fatty acids having the 1-methylpropyl group exhibited an interesting activity inhibiting beta-lactamases.