Faculty Bibliography

Glucose-6-phosphate dehydrogenase (G6PD) plays an important role in cellular redox homeostasis, which is crucial for cell survival. In the present study, we found that G6PD status determines the response of cells exposed to nitric oxide (NO) donor. Treatment with NO donor, sodium nitroprusside (SNP), caused apoptosis in G6PD-deficient human foreskin fibroblasts (HFF1), whereas it was growth stimulatory in the normal counterpart (HFF3). Such effects were abolished by NO scavengers like hemoglobin. Ectopic expression of G6PD in HFF1 cells switched the cellular response to NO from apoptosis to growth stimulation. Experiments with 1H- inverted question mark1,2,4oxadiazolo inverted question mark4, 3-aquinoxalin-1-one and 8-bromo-cGMP showed that the effects of NO on HFF1 and HFF3 cells were independent of cGMP signalling pathway. Intriguingly, trolox prevented the SNP-induced apoptosis in HFF1 cells. These data demonstrate that G6PD plays a critical role in regulation of cell growth and survival.

The authors report a 15-year history of management of multiple recurrent neuromas in a patient with an amputated arm. Various surgical modalities were employed, including burying the nerve ends in muscle and bone. In addition, they also treated successfully one of the neuromas in this patient by capping the transected nerve with an extended autologous vein graft. This application of the extended autologous venous nerve conduit may be a novel alternative in the treatment of this challenging problem

There are numerous methods cited in the literature on the treatment of painful neuroma. Nonsurgical methods range from injections with various materials into the nerve end to desensitization of nerve pain conduction pathways. Some surgical treatments aim to alter the environment of the amputated nerve end by transposing it into muscle or bone, others have designed various flaps to protect truncated nerve ends from scar tissue, and still others try to 'cap' the nerve with silicon, a nerve graft, or epineurium to prevent nerve regeneration. All of these methods have proved efficient. However, none of these methods work universally. The authors review the common treatments for painful neuromas. In addition, they review the preliminary results of the extended autologous venous nerve conduit as a novel technique of treating painful neuromas. They also report recent investigations into the pathophysiology of injured nerves

Feedback control has been postulated to improve the efficacy of laser welding in microsurgery, but alteration of outcome has not been clearly shown. The authors evaluated the ability of an optical closed loop temperature feedback control to improve patency, aneurysm rate, and to histologically limit thermal damage. Rat femoral artery anastomoses were performed under operating microscope magnification. One hundred and twenty-four anastomoses were performed in five groups using 1) free-hand (FH) 1.9-microm laser soldering without feedback; 2) temperature controlled (TC) 1.9-microm laser soldering with optical feedback; 3) FH 808 nm laser; 4) TC 808 nm laser soldering; and 5) 10-0 nylon suture control. In Groups 2 and 4, an optical feedback system controlling laser exposure to produce a preset temperature was used. Anastomotic time was significantly less for all laser groups (p < 0.05). Late patency for all 1.9-microm laser anastomoses was almost 0. Temperature controlled 808-nm anastomoses showed no significant difference from sutures in terms of patency (88 percent vs. 96 percent), bursting pressure, and aneurysm rate, while freehand 808-nm anastomoses had a significantly lower patency (71 percent) and more tissue damage (ANOVA, p < 0.05). The authors conclude that temperature control improves outcome in microvascular anastomosis by reducing transmural thermal injury caused by variations in surgeon technique

With the use of microsurgery, we have developed a method of measuring hemodynamic parameters in a rat not possible with previous technology. Three groups of rats were studied: a chemically induced pulmonary hypertensive group (PH); a chemically induced pulmonary hypertensive group treated with single lung transplantation (LT); and an untreated, control group (C). Cardiac output, heart rate, and pulmonary vascular resistance were then calculated in each group from data obtained by 1 mm high fidelity micromanometers and an ultrasonic flow probe. The results show that the data collected from the rodent model are reproducible within each group, and data quality is comparable to large animal models. With this new method, data can be collected in a small animal model at a fraction of the time and cost of large animal studies. Additionally, the complications of graft rejection in large animal studies are eliminated in an isogenic rodent model.

The posterior intermuscular approach emphasizes preservation of the soleus muscle by an intermuscular surgical approach to the vessels of the leg. The dissection proceeds from a normal zone proximally toward the zone of injury and facilitates selection of the site of microanastomosis. The neurovascular supply of the soleus is guarded, and its numerous venous channels are avoided. The indications and surgical planning are discussed. Two illustrative cases are presented

A novel method to release the carpal tunnel is presented. It combines the advantages of endoscopic and open techniques while utilizing standard instruments. A lighted Killian nasal speculum is introduced between the palmar fascia and the transverse carpal ligament. The ligament is incised under direct vision. The procedure was performed in 28 cadaver hands and followed by inspection utilizing the open method through an interthenar incision. The transverse carpal ligament was completely divided in all hands without nerve or tendon injury. The superficial palmar arch was injured in one hand (3.6 percent). The advantages, disadvantages, pitfalls, and results are discussed. The technique is simple and effective, employs inexpensive instruments, and has a low complication rate

Complete, stable chest-wall reconstruction was accomplished in a single operative procedure, using a fasciocutaneous free forearm flap based on the brachial artery. This allowed coverage of an extensive chest-wall defect

A comparative experimental study has been carried out in rats with denervated gastrocnemius muscles. Three groups of five rats were treated by three different types of implantation of nerve directly into muscle (neurotisation). In the fourth group, the common peroneal nerve was sutured to the transected tibial nerve. The fifth group was left denervated as a control. The muscles were studied by serial electrodiagnostic studies and later histologically. The results showed little difference between nerve suture and implantation of nerve directly into muscle. Extension of the common peroneal nerve with a pair of sural nerve grafts did not produce a detrimental effect

The external ear of the rat is an excellent model for practicing microsurgical dissection and for the refinement of microvascular anastomoses, techniques that are crucial for microvascular en bloc tissue transfer and replantation. Preparation of the rat ear for replantation requires familiarity with the vascular anatomy and gentle tissue handling with atraumatic dissection of arterial and venous pedicles, steps similarly crucial in raising free flaps for microvascular transfer. The strategy of performing accurate reduction and stabilization of the tubal cartilage prior to vessel repairs, anastomosing the more deeply seated external carotid artery prior to the more superficial posterior facial vein, is as critical to rat ear replantation as for digital reattachment. In addition, the rat ear as compared to other animal models such as the rabbit ear or canine hindlimbs is much less expensive. Compared to the rat hindlimb model, rat ears are much easier to observe, which is a distinct advantage when used as a model for long-term study of replantation, revascularization, or transplantation.