Isolation of a 90-kD Microtubule-Associated Protein from Tobacco Membranes

The organization and function of microtubules in plant cells are important in key developmental events, including the regulation of directional cellulose deposition. Bridges connecting microtubules to each other and to membranes and other organelles have been documented by electron microscopy; however, the biochemical and molecular nature of these linkages is not known. We have partitioned proteins from a suspension culture of tobacco into cytosolic and membrane fractions, solubilized the membrane fraction with a zwitterionic detergent, and then used affinity chromatography and salt elution to isolate tubulin binding proteins. Dark-field microscopy of in vitro-assembled microtubules showed that the eluted proteins from both fractions induce microtubule bundling and, in the presence of purified tubulin, promote microtubule elongation. Gel electrophoresis of the eluted proteins revealed two distinct sets of polypeptides. Those in the membrane eluate included unique bands with apparent molecular masses of 98, 90, and 75 kD in addition to bands present in both eluates. The cytosolic eluate, in contrast, typically included relatively smaller proteins. The eluted proteins also bound to taxol-stabilized microtubules. Initial immunological characterization using monoclonal antibodies raised against the 90-kD polypeptide showed that it is colocalized in situ with cortical microtubules in tobacco protoplast ghosts.

Experience with the resection of parapharyngeal cancers via the infratemporal fossa approach

Between 1982 and 1984, a modified infratemporal fossa approach was used to resect cancers with extensive primary or secondary involvement of the infratemporal fossa and parapharynx in 10 patients. Nine patients exhibited persistent or recurrent disease of the upper aerodigestive tract and posterior cranial fossa following planned, curative-intent therapy; the remaining patient had a carcinoma ex-pleomorphic adenoma of the deep lobe of the parotid gland with a significant infratemporal fossa extension. Considered to have "unresectable" tumors, by traditional methods, 7 of the 10 patients underwent an en-bloc resection of their lesions with tumor-free margins. Tumor was present at the margins of the specimens in the other 3 patients. Two of the 10 patients died early in the postoperative period of medical complications. Another died 5 months postoperatively of a tumor-induced internal carotid artery rupture at the level of the foramen lacerum. A fourth patient died of his disease 6 months following his resection. One patient is alive, but has metastatic meningioma 2 years after surgery. The 5 remaining patients are without evidence of disease, with a mean follow up of 2 years. Indications for and refinements of the operative technique, particularly those related to the repair of such extensive ablative defects, are outlined on the basis of this early experience.

Stage T3 squamous cell carcinoma of the glottic larynx treated with surgery and/or radiation therapy

This is a retrospective analysis of 68 patients with Stage T3 squamous cell carcinoma of the glottic larynx treated with surgery and/or irradiation from March 1965 to April 1981 at the University of Florida. Follow-up ranged from 2 to 17.5 years. Initial local-regional control of disease above the clavicles (i.e., prior to salvage attempts) by treatment technique for patients at risk for greater than or equal to 2 years was 11/19 (58%) with irradiation alone, 5/7 (71%) with preoperative irradiation and surgery, 8/9 (89%) with surgery and postoperative irradiation, and 18/23 (78%) with surgery alone. Initial control of disease at the primary site was accomplished in 11/18 (61%) treated with radiation therapy alone, and ultimate control of the primary was obtained in 15/18 (83%) after surgical salvage. Analysis of complications and survival is included, and treatment recommendations are discussed.