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Biomedical subjects

Harry J Buncke

Publications and source records attributed to Harry J Buncke.

12 recordsLinked to original sources
PubMed2006

Induction of tolerance to composite tissue allograft in a rat model.

The goal of this study was to establish a rat model that can be used to determine the variables in influencing induction of tolerance to composite tissue allografts. An anti T-cell depleting agent (R73) and 15-deoxyspergualin were given in different doses and schedule to four groups of Lewis rats receiving a limb transplant from Brown-Norway donors. Graft survival prolongation was maximal combining a single dose of R73 and a 20-day administration of 15-deoxyspergualin. Long-term survivors accepted a skin graft from Brown-Norway donors at 80 days, but rejected grafts from an unrelated donor. Skin grafting did not influence survival of the transplanted limb. Mixed allogeneic chimerism was not detectable in peripheral blood by flow cytometry, but immunohistochemistry identified donor-derived cells in the thymus of tolerant recipients at 100 days. These results suggest a state of donor-specific, dynamic tolerance, with potential for future application in human composite tissue allotransplantation.

Animals↗
PubMed2006

Detection of perfusion disturbances in digit replantation using near-infrared spectroscopy and serial quantitative fluoroscopy.

PURPOSE: The postoperative monitoring of digit replants continues to be a challenge. Current objective methods of digit monitoring have not been adopted widely because of their complexity or lack of sensitivity. Because tissue oxygen tension correlates directly with vascular inflow, a device that tracks changes in tissue oxygenation may be useful to monitor the perfusion and viability of digits after revascularization. A clinical study was undertaken to evaluate noninvasive monitoring of tissue oxygenation using near-infrared spectroscopy in postoperative digit replantation. METHODS: Forty-eight patients were enrolled and 64 digits were monitored at 1 institute. There were 43 male and 5 female patients with an average age of 41 years (range, 13-79 y). Digits were monitored by clinical examination, fluorescein, and a tissue oximeter at 1- to 2-hour intervals for 24 to 48 hours. RESULTS: Sixty-one digits survived and 3 digits failed. In the surviving digits the fluorescein and tissue oxygen saturation (StO2) readings were similar to the control digit readings. There were no significant differences between fluorescein and StO2 or between StO2 readings for control and surviving digits. In the digits that failed to survive both fluorescein and StO2 readings were significantly lower in the failed compared with control digits. The StO2 values for failed digits were 30% to 70% lower and showed greater variation than the StO2 values for the control digits. There were no complications associated with fluorescein or tissue oxygenation measurements. CONCLUSIONS: Near-infrared spectroscopy measurement of tissue oxygenation correlates with fluorescein monitoring and digit perfusion. This noninvasive monitoring is easy, reliable, safe, and useful in postoperative monitoring of digit replantation. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic, Level I.

Adolescent↗
PubMed2004

The effect of single administration of vascular endothelial growth factor or L-arginine on necrosis and vasculature of the epigastric flap in the rat model.

OBJECTIVES: Vascular endothelial growth factor (VEGF) and nitric oxide (NO) produce vasodilation, induce angiogenesis, and improve survival of surgical flaps. We used the rat epigastric skin flap to study the effect of a single intra-arterial dose of VEGF or L-arginine, a substrate for NO production, on flap regional necrosis and pedicle dependence of flap perfusion. METHODS: In 30 Sprague-Dawley rats an 8 x 8 cm2 skin flap, consisting of four vertical zones marked A through D (right to left), based on the proximal right inferior epigastric vessels was raised. Subsequently, 1 ml of either saline (control, n =10), 5 microg VEGF (VEGF, n = 10), or 50 mg of L-arginine (L-arginine, n = 10) was injected into the arterial pedicle by cannulating the right saphenous artery, and the flap was resutured in place. After 8 days, the animals were perfused systemically with 15 microm coloured fluorescent microspheres before (blue) and after (yellow-green) ligation of the right inferior epigastric vascular pedicle. After sacrifice, the area of flap necrosis was measured in each zone by templates and weight-to-surface ratio, and the flap zones were harvested and processed for determination of fluorescence and blood flow. RESULTS: Administration of VEGF or L-arginine resulted in decreased total and regional (zone D) flap necrosis (ANOVA <0.001). The total and regional flap shrinkage was greater in the experimental groups (ANOVA <0.02). While VEGF and L-arginine decreased the percentage of necrosis in the zone most distal to the pedicle (ANOVA <0.01) only L-arginine diminished percentage of total flap necrosis (p = 0.04). In the VEGF group, total and regional flap perfusion did not change after pedicle ligation, but perfusion decreased significantly in zones B through D in the L-arginine treated rats. CONCLUSION: Single intra-pedicle administration of VEGF or L-arginine decreased necrosis of the epigastric skin flap at 8 days postoperatively, but flap shrinkage also increased in the zone with the greatest degree of necrosis. Perfusion data suggest that beneficial effects of VEGF and L-arginine on flap survival may be based on different mechanisms.

Analysis of Variance↗
PubMed2004

Oral administration of L-arginine decreases necrosis of the epigastric skin flap in the rat.

BACKGROUND: We investigated the effect of prolonged oral arginine administration on tissue necrosis and perfusion in the rat skin flap. METHODS: Twenty-five Sprague-Dawley rats had an 8 x 8 - cm epigastric skin flap elevated and were divided in 2 groups, l-Arginine and Control, which respectively received oral 6% l-arginine solution or water for 8 days postoperatively. On postoperative day 8, area of flap necrosis was measured, and the animals were perfused systemically with 15-microm colored fluorescent microspheres before (blue) and after (yellow-green) ligation of the flap pedicle. RESULTS: l-Arginine reduced total flap necrosis (6.53 +/- 3.76 cm versus 11.91 +/- 4.12 cm; P < 0.01). After pedicle ligation, total flap perfusion remained unchanged in Control but diminished in the l-Arginine group (Control: 0.47 +/- 0.23 and 0.42 +/- 0.06; P = nonsignificant versus l-Arginine: 0.58 +/- 0.29 and 0.27 +/- 0.19; P < 0.01). Serum levels of l-arginine were higher in the l-arginine-treated animals (504 +/- 154 versus 152 +/- 34 micromol/l; P < 0.0001). CONCLUSIONS: Postoperative oral administration of l-arginine decreased flap necrosis in the rat epigastric skin flap. Flap perfusion following oral l-arginine was more dependent on the main vascular pedicle.

Administration, Oral↗
PubMed2003

Composite tissue allografting (CTA).

Composite tissue allografting (CTA) is a relatively new term that appears with increased frequency in the medical and surgical literature. The recent successful allografts, or homotransplantations, of hands has sparked a resurgence of research, both experimental and clinical. Plastic surgeons have long been interested--particularly in the field of skin grafts for extensive burns and wounds--but have been replaced by the organ transplant teams and immunogeneticists. The skin, one of the most strongly antigenic organs, has required such high levels of immunosuppressive drugs to date, that elective transplants of skin and other composite tissues have received little attention.

Animals↗
PubMed2002

Cross-facial and functional microvascular muscle transplantation for longstanding facial paralysis.

Functional results continue to improve with advancing microsurgical techniques and monitoring to detect and correct problems within minutes [47]. However, failures do occur, even when one can project a 98% survival for the transplant. Figs. 9 and 10 show two of our early cases that were fortunately salvaged with a second microvascular transplant. Evaluation of the result is a continuing challenge--anatomically, physiologically, and psychologically [37]. If one can remove the stigma or stigmata of facial paralysis in the patient's mind. success has been achieved (Fig. II) [48].

Eyelids↗
PubMed2002

Effect of sequence, timing of vascular anastomosis, and clamp removal on survival of microsurgical flaps.

The effects of the timing and order of clamp removal in microsurgical transplants were studied in rat groin skin flap and rat latissimus dorsi muscle flap models. Forty rats were divided into four groups. In Group 1, the arterial pedicle of the skin flap was anastomosed first, and the clamp was released after the anastomosis was completed. The venous pedicle was then repaired after inflow was restored. In Group 2, the venous pedicle of the skin flap was anastomosed first. The venous clamp was not released until completion of the arterial anastomosis. In Group 3, the arterial pedicle was anastomosed first in the muscle flap. The venous anastomosis was then performed after the arterial clamp was released. In Group 4, the venous pedicle was anastomosed first, and both clamps were released simultaneously. The blood perfusion of the skin flaps was examined after both clamps were released in Groups 1 and 2. The flap survival status was examined 5 days postoperatively for skin flaps and at 3 days for muscle flaps. Skin flaps in an additional six rats were harvested for histology. The results showed that the flap blood flow for Group 1 was statistically significantly higher than for Group 2 flaps in the first 20 min after reperfusion. There was no significant difference of flow between these two groups during the 30 to 90 min after reperfusion. The difference in survival rates for the four groups was not significant. Histology revealed extensive congestion in the flaps from Group 1 after completion anastomoses, but the congestion was significantly decreased at 3 hr following reperfusion. In conclusion, a brief venous stasis during anastomosis, after establishment of arterial inflow, is not detrimental to flap survival. The sequence of anastomosis will not affect outcome for either the cutaneous flap or the muscle flap models. Early flap perfusion was increased when the arterial anastomosis was performed first.

Analysis of Variance↗
PubMed2002

Use of a venous flap from an amputated part for salvage of an upper extremity injury.

The authors describe a patient in whom a large arterialized venous flap was harvested from a nonreplantable part after partial hand amputation. A 9 x 6-cm segment of dorsal hand skin was transplanted acutely in an artery-vein-vein fashion to cover exposed bone, joints, and reconstructed tendons. The flap provided durable coverage, and at 1 year the patient regained 94% total active motion at the index finger and 99% total active motion at the long finger. Salvage of component parts such as a venous flap and extensor tendons avoided additional procedures for coverage and staged tendon reconstructions.

Adult↗
PubMed2002

Effect of cryopreservation on patency and histological changes of arterial isogeneic and allogeneic grafts in the rat model.

Vascular grafting is used frequently in the management of length discrepancies between blood vessels. Cryopreservation permits vascular graft storage and aids availability; however, long-term patency of cryopreserved arterial allografts is not well established. Fifty Fisher and 55 Wistar rats were used in the study. Thirty-eight cryopreserved Fisher femoral arterial grafts were transplanted into the femoral arteries of 15 Fisher (cryoisografts) and 23 Wistar rats (cryoallografts). Thirty-two fresh Fisher arterial grafts were implanted into 32 Wistar femoral arteries (fresh allografts). The animals were killed at 1, 4, and 8 months in each group, and graft patency was assessed. One-month graft patency was 100% in all groups. At 4 months, graft patencies were 86%, 100%, and 75% in the cryoisografts, cryoallografts, and fresh allografts respectively. All cryoisografts and fresh allografts were patent, whereas all the cryoallografts were occluded at 8 months ( < 0.01). Cryopreserved rat arterial allografts offered satisfactory graft patency up to 4 months after implantation and may therefore be applicable clinically in selected cases.

Animals↗
PubMed2002

The harvest and clinical application of the superficial peroneal sensory nerve for grafting motor and sensory nerve defects.

Potential donor nerves for autografting are finite and usually limited to cutaneous nerves of the extremities. The superficial peroneal nerve is the major lateral branch of the common peroneal nerve that innervates the peroneus longus and brevis muscles and provides sensation to the lateral aspect of the lower leg and the dorsal foot. It has generally been overlooked as a potential donor of nerve autografts. Cadaver dissections were performed on 10 fresh lower extremity specimens to investigate the anatomic characteristics of the superficial peroneal nerve and to refine a harvesting technique for the nerve. Thirty-one patients underwent nerve grafting of 39 upper and lower extremity nerves using the superficial peroneal donor. There were nine median nerves, four ulnar nerves, two radial nerves, two brachial plexus lesions, 16 digital nerves, and six lower extremity nerves grafted. The superficial peroneal nerve provided a consistently long donor, comparable in length to the sural nerve. The anatomic pattern is consistent, the patient positioning is simple, the surgical harvesting technique is straightforward, and the donor defect is acceptable. The superficial peroneal nerve provides a safe and valuable donor nerve, particularly in cases where multiple or very long nerve grafts are required.

Adolescent↗