Beneficial effects of ibuprofen on experimental microvascular free flaps: pharmacologic alteration of the no-reflow phenomenon

Pharmacologic alteration of the no-reflow phenomenon was determined based on increased tolerance to ischemia in ibuprofen-treated free flaps. Sprague-Dawley rats (N = 60) were divided into control (lactated Ringer's) and treated (ibuprofen) groups and subdivided into six groups of ischemia: 1 hour, 6 hours, 8 hours, 10 hours, 12 hours, and 14 hours of ischemia. Fluorescein uptake was measured after 10, 30, and 60 minutes following microrevascularization. Dye elimination studies were done for each ischemia group that demonstrated good fluorescein uptake. All free flaps in the 1-, 6-, and 8-hour groups survived. The ibuprofen-treated 10- and 12-hour flaps all survived, whereas the 10-hour control and 14-hour ibuprofen-treated free flaps failed to survive. Despite high fluorescein uptake, the 14-hour ibuprofen-treated flaps did not eliminate the fluorescein, whereas all surviving free flaps adequately eliminated the fluorescein. Failure to eliminate dye despite adequate uptake suggested a deranged microcirculation with increasing ischemia time. By inhibiting cyclo-oxygenase, nonsteroidal anti-inflammatory agents such as ibuprofen may block the untoward effects mediated by thromboxane A2, such as vasoconstriction, microvasculature thrombus formation, and intravascular sludging. These effects are theorized in part to be responsible for the failure of a free flap to survive despite revascularization.

Comparative cytogenetics of Chinese and Japanese raccoon dogs, Nyctereutes procyonoides

We investigated the relationships between subspecies of Nyctereutes procyonoides from China (2n = 54 + B chromosomes) and Japan (2n = 38 + B chromosomes). The chromosomes of Chinese and Japanese raccoon dogs were compared by means of conventional staining, G- and C-banding, and silver nitrate staining of NORs. Extensive G-banding homologies revealed karyotype evolution through chromosomal fusion. We believe the reduced diploid number in the Japanese raccoon dogs was achieved by fusion of 16 acrocentrics to form eight metacentric and submetacentric elements. Ten pairs of autosomes appeared to be identical in these subspecies and were presumed to have occurred as such in a common ancestor. G-band patterns of the sex chromosomes were similar in the two subspecies, but differences were noted with other banding and staining techniques. B chromosomes were present in varying numbers and sizes in all animals examined, but the morphology of the B chromosomes differed in the two subspecies. It was concluded from chromosomal and paleontological evidence that the two subspecies were derived from a common mainland ancestor and that the Japanese raccoon dogs is a relatively recent form.

Ischemic induction of neovascularization: a study by fluorometric analysis

The dynamic process of skin flap neovascularization can be quantitated in a relatively non-invasive fashion in an "in-vivo" model using the technique of perfusion fluorometry. The extent of skin flap ischemia can be monitored, and its effect on angiogenesis rapidly determined. Evidence is presented that indicates that angiogenesis develops from a distal to proximal direction corresponding to the degree of ischemia as measured by fluorescein uptake and elimination. Furthermore, although certain proximal segments of skin flaps demonstrated no uptake or elimination, survival could still occur, indicating that neovascularization need not be complete at the time of pedicle interruption.

Enhancement of blood flow in experimental microvascular free flaps

Prolonged ischemia may result in tissue death because of the no-reflow phenomenon. By raising a flap 24 hours prior to subjecting it to ischemia, the authors have been able to significantly lengthen the ischemia interval prior to the onset of tissue death. These effects are believed to be the result of alteration of the no-reflow phenomenon.

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.