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Biomedical subjects

Darrell Brooks

Publications and source records attributed to Darrell Brooks.

13 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↗
PubMed2006

Improvement of venous flap survival by application of vascular endothelial growth factor in a rat model.

Expression of vascular endothelial growth factor (VEGF) in the venous flap and the effect of exogenous VEGF on survival of the venous flap were studied in rats. A 4- x 4-cm groin type 2 venous skin flap was used in the study. In part 1, biopsies were taken from the flap at 0, 6, 12, 24, and 48 hours after the flaps were raised. VEGF gene expression was measured. In part 2, exogenous VEGF (1 microg/mL) was injected subdermally into the flaps in 10 rats before the flaps were replaced. Flaps that received a saline injection were used as the control. Skin paddle survival was measured on postoperative day 7. The results showed that VEGF expression was significantly increased at 24 and 48 hours after venous flap elevation (P < 0.05). Injection of exogenous VEGF to the flap significantly improved survival of the flap (73% of the flap) when compared with the control, which had a 39% mean percent survival (P < 0.05). We conclude that VEGF expression was increased in the venous flap. Administration of exogenous VEGF significantly improved survival of the venous flap.

Animals↗
PubMed2005

Temporary innervation of a primary coverage muscle: a new technique to optimize function in a subsequent functional microvascular muscle transplant.

The author describes the simple technique of innervating the coverage muscle in the staged reconstruction of an upper-extremity crush-avulsion injury with a functional microvascular muscle transplant (FMMT). The thoracodorsal nerve was repaired to the mixed motor-sensory radial nerve above the elbow. Contraction of the latissimus muscle at 8 months after nerve repair signaled the adequacy of the 10-cm thoracodorsal nerve graft as a target motor nerve for the eventual FMMT. Excursion of the latissimus muscle created a septo-alveolar plane similar to the plane between two healthy muscles into which the FMMT could be placed. The author also discusses the potential advantages of early thoracodorsal nerve repair for successful nerve regeneration. This simple technique helped overcome the potential limitations to functional muscle transplantation in the severely traumatized upper extremity, and deserves applied study.

Adult↗
PubMed2005

An aesthetic perquisite of rectus muscle transplantation in extremity reconstruction.

The authors combine a rectus abdominis muscle harvest with a mini-abdominoplasty in patients with Matarasso type II and III body types admitted for extremity reconstruction. The dermo-lipectomy tissue was used as a source for split-thickness skin graft. Twenty-five patients underwent the combined procedure. All flaps survived. Average quantity of skin harvested from the dermo-lipectomy tissue was 150 cm2 (range 100-250 cm2). Twenty-three of 25 (92%) required no additional skin grafting. The remaining 2 cases required less than 50 cm2 of additional split-thickness skin graft. There were no complications related to the mini-abdominoplasty. All patients were satisfied with their abdominal recontouring. The combined procedure results in an aesthetic improvement at the abdominal donor site and elimination or significant reduction of the morbidity related to a conventional skin graft donor site at the upper lateral thigh. This technique also allows thicker skin graft harvest without an associated increase in morbidity. The authors believe that this technique should be considered for patients with appropriate body habitus when a rectus abdominis muscle is the flap of choice or when multiple flaps including the rectus abdominis muscle are equal for the task.

Abdominal Wall↗
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

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↗