Faculty Bibliography

A new experimental model of a vascular carrier to prefabricate a "secondary" island flap, the popliteal musculovascular pedicle, was developed in the rat. Using quantitative skin-surface fluorometry 30 minutes after sodium fluorescein injection and a flap survival area in the prefabricated 8 x 2.5-cm abdominal composite island flap, we compared the revascularization ability of our muscular carrier to nonrevascularized controls: the skeletonized arteriovenous pedicle and the fasciovascular pedicle. The free composite graft with no vascular carrier exhibited near-total necrosis. The skeletonized vascular pedicle demonstrated 15.2% +/- 7.8% perfusion of normal skin on dye fluorescence index measurements and 50% flap survival. The fasciovascular pedicle exhibited better revascularization, with a dye fluorescence index of 36.2 +/- 15.5 (p < 0.01) and 90% +/- 10% flap survival (p < 0.001). India ink injection study and histological examination of our model provided visual evidence of revascularization from the musculovascular pedicle, along with preservation of the carrier's muscular architecture. The musculovascular pedicle is a reliable carrier for making new, vascularized composite flaps.

In the setting of traumatic injury, obtaining suitable coverage to salvage a below-the-knee amputation has been performed by using a variety of tissue flaps, including the fillet of foot free flap. This flap is a free tissue transfer that utilizes the soft tissues of the foot for stump coverage. In this report, we present a 15-year follow-up of a patient with a fillet of foot free flap to demonstrate its applicability and long-term efficacy. We also discuss technical aspects for performing this procedure. In this follow-up, we have found the flap to be extremely durable, even when placed in the weight-bearing position of the stump, and also lacking many of the usual complications associated with the weight-bearing portion (e.g., blisters, ulcerations). We conclude that the fillet of foot free flap is an excellent salvage flap for providing long-term length, coverage, and durability in an amputated, weight-bearing extremity.

Methods of prevention of falls in the home may differ for healthy and frail individuals. We therefore sought to determine whether measures of health and functioning in older persons are more useful in predicting falls at home not involving home hazards (non-environmental falls) than falls at home related to home hazards (environmental falls), and whether these relationships differ among those who fell once and those who fell multiple times during follow-up. Data for this analysis are from a 1-year prospective cohort study of 325 community-dwelling volunteers aged 60-93 years who had fallen during the year before baseline. In general, associations were stronger between poor functional ability and non-environmental falls than between poor functional ability and environmental falls. Independent predictors of non-environmental first falls during follow-up included Parkinson's disease (adjusted odds ratio (AOR) 7.66, 95% confidence interval (95% CI) 1.15-51.1) and being home alone 10 or more hours per day (AOR 2.36, 95% CI 1.20-4.61); independent predictors of environmental first falls during follow-up included arthritis (AOR 2.60, 95% CI 1.32-5.09) and poor depth perception (AOR 0.73, 95% CI 0.59-0.89, for each unit increase in depth perception score). Also, associations between poor function and falls were generally stronger among participants who fell repeatedly than among individuals who fell only once during the follow-up year. In conclusion, poor function predisposes to non-environmental falls at home in older persons and, to a lesser extent, environmental falls in those who fall repeatedly. Certain functional characteristics such as poor depth perception may predispose to environmental falls to a greater extent than do other disabilities.

Accuracy of cephalometric tracings and model surgeries is of utmost importance in planning for orthognathic surgery. The technique described allows surgeons to verify position of the models by superimposing a cephalogram of the mounted models over that of the patient. It also reduces the chance of error during actual surgery by placing models in centric relation. Therefore, the possibility of intraoperative complications, and thus longer operating times, is minimized.

The biology underlying normal and premature cranial suture fusion remains unknown. To develop a model for normal cranial suture fusion, the temporal sequence of the posterior frontal cranial suture fusion in the mouse was determined. To do this, all the cranial sutures of three distinct strains of mice (CD-1, CF-1, and C57bl-6) were studied histologically for fusion at sequential time points. Two studies were set up using group A mice (n = 72, all sutures studied) and group B mice (n = 78, only the posterior frontal suture studied, but more precisely along its anatomic length). In the group A cranial suture study, mice were sacrificed starting at newborn age and then every 5 days until age 50 days. In addition, two mature mice (250 days old) from each strain were sacrificed. In all three mouse strains, histologic examinations showed that the anterior frontal, sagittal, coronal, lambdoid, and occipitointerparietal sutures remained patent at up to 50 days of age and were patent in the 250-day mature mice. However, examination of the midpoint of the posterior frontal suture showed patency at 30 days, partial fusion at 35 days, and complete fusion by 40 days. These data prompted the posterior frontal suture fusion study. In the group B posterior frontal suture fusion study, mice were sacrificed at age 23 days and then every 2 days until 47 days of age. The anterior, midpoint, and posterior aspects of the posterior frontal suture were examined: The anterior aspect fused between 25 and 29 days; the midpoint fused between 31 and 37 days; and the posterior aspect fused between 39 and 45 days. These data indicate that fusion of the posterior frontal cranial suture in the mouse proceeds in a defined temporal sequence from an anterior to posterior direction in three distinct strains of mice, while in the same mice all other cranial sutures remain patent. By describing and understanding the fusion of the normal posterior frontal suture, a biologic basis of normal suture development and fusion can be established and used as a comparison for murine cranial sutures altered surgically, biochemically (with growth factors), or genetically (with craniosynostotic phenotypes)

Rare individuals have been multiply exposed to HIV-1 but remain uninfected. The CD4+ T-cells of two of these individuals, designated EU2 and EU3, are highly resistant in vitro to the entry of primary macrophagetropic virus but are readily infectable with transformed T-cell line adapted viruses. We report here on the genetic basis of this resistance. We found that EU2 and EU3 have a homozygous defect in CKR-5, the gene encoding the recently described coreceptor for primary HIV-1 isolates. These individuals appear to have inherited a defective CKR-5 allele that contains an internal 32 base pair deletion. The encoded protein is severely truncated and cannot be detected at the cell surface. Surprisingly, this defect has no obvious phenotype in the affected individuals. Thus, a CKR-5 allele present in the human population appears to protect homozygous individuals from sexual transmission of HIV-1. Heterozygous individuals are quite common (approximately 20%) in some populations. These findings indicate the importance of CKR-5 in HIV-1 transmission and suggest that targeting the HIV-1-CKR-5 interaction may provide a means of preventing or slowing disease progression