Function-sparing surgery for desmoid tumors and other low-grade fibrosarcomas involving the brachial plexus.

OBJECTIVE: Low-grade fibrosarcomas and desmoid tumors present a surgical challenge in that they have a strong tendency for local invasion, surgical margins are poorly delineated, and complete resections are difficult. Nowhere is this more evident than in those lesions involving the brachial plexus. We review our experience with these difficult lesions. METHODS: From a prospective database of 2900 patients admitted for treatment of sarcoma between 1982 and 1996, we identified 15 patients with involvement of the brachial plexus by a low-grade fibrosarcoma or desmoid tumor. All patients underwent resection, with 13 of 15 receiving adjuvant radiotherapy. The 15 patients had a mean age at initial operation of 47 years. The male-to-female ratio was 8:7. The mean follow-up period was 65 months (median, 53 mo). RESULTS: Gross total resection was achieved in 12 patients (80%), although 11 of these patients had positive surgical margins. Overall, 64% of the tumors have recurred locally. There were no distant metastases, and no patients died as a result of their disease. One patient died as a result of unrelated cancer. An assessment of the functional outcomes revealed seven patients with normal function or mild neurological deficits and eight who were suffering from significant weakness, debilitation, or chronic pain. One patient required forequarter amputation. CONCLUSION: Surgical resection plus postoperative radiotherapy is the treatment of choice for low-grade fibrosarcomas and desmoid tumors involving the brachial plexus. However, aggressive surgical management with the goal of achieving a gross total resection with negative histological margins can produce unnecessary morbidity. Preserving function should be a primary goal of the operations, although this will be associated with residual disease and will risk local recurrence but rarely death resulting from the disease.

Modulation of cultured brain, adrenal, and aortic endothelial cell glucose transport.

Studies of glucose transporter activity and anti-glucose transporter (GLUT1) immunoblots were performed on different endothelial cell primary cultures (brain capillary, adrenal capillary and aortic) to determine their response to glucose deprivation. Cell cultures were exposed to glucose deprivation (0.5 mM) for 48 h periods and refed (11.0 mM) for 36 additional hours. Control cultures were kept in 11.0 mM glucose for the duration of these studies. Measurements of 2-[3H]deoxy-D-glucose uptake and membrane fraction purification were performed every 12 h during these timecourses. Baseline cytochalasin-B sensitive uptake of 2-deoxy-D-glucose was near three times larger in brain capillary endothelial cells than in adrenal or aortic endothelial cultures. In all three endothelial cell cultures, 2-deoxy-D-glucose uptake increased during glucose deprivation, and returned to control values upon refeeding. Aortic and adrenal cortical endothelia expressed the starvation induced increases 12 h sooner than brain capillary endothelia. Return to control values was also 12 h faster in these cultured endothelia. Immunoblot studies showed that in all three endothelial cell cultures the increases in transporter activity during glucose starvation correlate with increased membrane expression of GLUT1. Quantitative analysis of the anti-GLUT1 immunoblots indicated that induction of GLUT1 following glucose starvation was slower in brain capillary endothelia than in aortic or adrenal endothelia. The slower response by brain capillary endothelial cells may be related to the higher transport rate of glucose in these cells.

Glucose is required to maintain ATP/ADP ratio of isolated bovine cerebral microvessels.

Isolated bovine cerebral microvessels (ICMV) were incubated with different metabolic fuels to determine the effect of each of them on microvessel energy state. With no fuel added to the medium, the ATP/ADP generally decreased from initial values of 1.5-3 down to 1-1.5 over 4 h; the ATP content also declined approximately 50%. In contrast, with glucose present, the ATP/ADP increased, and the ATP content was maintained. Pyruvate, beta-hydroxybutyrate, glutamate, and oleate were ineffective; oleate added together with carnitine gave some improvement but less than with glucose. Oxygen consumption by ICMV did not differ appreciably in fuel-free or glucose-containing medium. Addition of an inhibitor of fatty acid oxidation, 2-tetradecylglycidate, depressed the ATP/ADP. These results suggest that ICMV require glycolysis to maintain both their content of ATP and their ATP/ADP. They also suggest that endogenous lipid is an important fuel for isolated microvessels.