Faculty Bibliography

Distraction of the frontal bone outside the cranial plane using the Ilizarov principle was performed in 17 22-week-old New Zealand white rabbits. Five rabbits had frontal bone osteotomy only and were in the control group; 5 rabbits were placed in the sham control group and had frontal bone osteotomy plus application of a customized headgear appliance; and 7 rabbits were placed in the experimental group, which underwent frontal bone osteotomy application of the headgear and distraction. The frontal bone was elevated 1 mm every other day for a period of 8 weeks, and the animals were then killed. Cephalometry was performed both preoperatively and at the end of the 8-week period. Histological examination of the skulls was also performed. The experimental group showed a significantly elevated frontal bone compared to the sham control group (p < 0.05). Callous bone filled the distracted segment, which united the frontal bone with the cranial plane. Therefore, frontal bone advancement by distraction osteogenesis is possible using this rabbit model

The chemical probes potassium permanganate (KMnO4) and diethylpyrocarbonate (DEPC) have been used to study the conformation of bent kinetoplast DNA from Crithidia fasciculata at different temperatures. Chemical reactivity data shows that the numerous short A-tracts of this bent DNA adopt a similar structure at 43 degrees C. This conformation appears to be very similar to the conformation of A-tracts in DNA exhibiting normal gel mobility. The A-tract structure detected by chemical probing is characterized by a high degree of base stacking on the thymine strand, and by an abrupt conformational change at the 3' end of the adenine strand. In general, no major alteration of this A-tract specific structure was detected between 4-53 degrees C. However, probing with KMnO4 revealed two unusual features of the C. fasciculata sequence that may contribute to the highly aberrant gel mobility of this DNA: 1) the B DNA/A-tract junction 5' dC/A3-6 3'. 5' dT3-6/G 3' is disproportionately represented and is conformationally distinct from other 5' end junctions, and 2) low temperature favors a novel strand-specific conformational distortion over a 20 base pair region of the bent kinetoplast DNA. Presence of the minor groove binding drug distamycin had little detectable effect on the A-tract conformation. However, distamycin did inhibit formation of the novel KMnO4 sensitive low temperature structure and partially eliminated the anomalous gel mobility of the kinetoplast DNA. Finally, we describe a simple and reproducible procedure for the production of an adenine-specific chemical DNA sequence ladder

No current method of flap monitoring is ideal for use in all types of free tissue transfers. No method provides objective, easily communicated data that is identical in all types of transfers. In particular, reliable monitoring of buried transfers has proved difficult with available methods. The rat anterior thigh flap based on the external iliac vascular pedicle was introduced by us as a model of deep free tissue transfer. Four sets of 10 flaps were raised in the following groups: Group A (control), Group B (arterial occlusion), Group C (venous occlusion), and Group D (arterial and venous occlusion). Postoperative muscle flap pH was measured with a micro-pH electrode (1.2 mm) and correlated with arterial blood gas. Results showed excellent correlation of flap and serum pH over time (mean flap pH, 7.28; mean serum pH, 7.30). Arterial occlusion produced a rapid drop in flap pH of 0.66 pH units at 1 hour. Venous occlusion pH drop was 0.27 pH units at 1 hour, 0.53 pH units at 3 hours. Arterial and venous occlusion produced a pH drop of 0.55 pH units at 1 hour. The most rapid rate of pH drop occurred immediately after vessel occlusion. We have used continuous pH monitoring in 21 free tissue transfers for up to 84 hours after surgery. PH values remained constant in each transfer (range, 7.20-7.50; grand mean, 7.35). There was one flap failure among the monitored group of flaps, which was predicted by pH drop before loss of Doppler pulse.(ABSTRACT TRUNCATED AT 250 WORDS)

The results of an anatomic investigation performed in 40 fresh cadaver specimens and 80 consecutive clinical cases of the posterior interosseous reverse forearm flap are reported. It was observed that there is a choke anastomosis between the recurrent dorsal branch of the anterior interosseous artery and the posterior interosseous artery at the level of the middle third of the posterior forearm. Ink injections through a catheter placed in the distal part of the anterior interosseous artery stained the distal and middle thirds of the posterior forearm, but the proximal third remained unstained; this secondary territory cannot be captured through the choke anastomosis between the anterior interosseous artery and the posterior interosseous artery. Intravital fluorescein injection into the distal arterior interosseous artery revealed (under ultraviolet light) that the distal third of the posterior forearm is irrigated by direct flow through the recurrent branch of the arterior interosseous artery (the traditionally called distal anastomosis of the interosseous arteries). Therefore, we can assume that the blood flow is not reversed when the so-called posterior interosseous reverse forearm flap is raised. From this point of view, this flap could be renamed as the recurrent dorsal anterior interosseous direct flap; however, the classical name is maintained for practical purposes. From the venous standpoint, the cutaneous area included in this flap belongs to an oscillating type of venous territory and is connected to the deep system through an interconnecting venous perforator that accompanies a medial cutaneous arterial branch located at 1 to 2 cm distal to the middle point of the forearm.(ABSTRACT TRUNCATED AT 250 WORDS)

This study examines the histologic and biochemical features of wound healing in a cleft lip model in the mid-third-trimester fetal rabbit. At days 1, 2, and 4 after the procedure, control, unrepaired, and repaired fetal heads were obtained, sectioned, and stained for histologic examination. The localization of hyaluronic acid in the wound was documented using a cartilage-derived hyaluronic acid-binding protein. In both repaired and unrepaired wounds, the fetal cleft healed without inflammatory cell infiltration or scar formation. Six months after birth, the repaired cleft showed complete regeneration of muscle across the wound and the collagen fibers were of normal density and orientation. Decreased hyaluronic acid deposition was observed in unrepaired clefts as compared with adjacent tissue; no such difference was detected in repaired clefts. Our findings support the hypothesis that a cleft lip repaired in utero heals without the scarring that accompanies postnatal repair. This may explain the lack of maxillary growth restriction after in utero cleft lip repair.

Although head injuries are usually easily recognized, other, less obvious lesions should also be promptly investigated. In either case, outcome is often determined in the first few minutes and hours of management.