Maxwell Abramson

Collagenase Activity in Epidermoid Carcinoma of the Oral Cavity and Larynx

Tumor invasion requires the breakdown of the main structural protein, collagen. A series of fourteen epidermoid carcinomas of the larynx and oral cavity produced a collagen dissolving enzyme in vitro as demonstrated by the breakdown of 14C-labeled collagen. Oral cavity tumors showed greater activity than laryngeal carcinomas while both sites were more active than uninvolved mucosa from the same patients. Tumor associated collagenase activity, in common with previously described collagenases, can only be demonstrated in vitro and requires protein synthesis. Maximum tumor collagenase occurred at 24 hours in vitro and then declined as compared with the maximum collagenase at 72 hours in vitro produced by oral cavity mucosa. The 14 patients in our series were ranked in order of the collagenase activity of their tumors. At 18 months after the diagnosis, four of the six patients with the most active tumors were dead of cancer and one patient was alive with persistent cancer. High collagenase activity may be a factor in the clinical aggressiveness of epidermoid carcinomas of the head and neck.

Interleukin 1 Causing Bone Destruction in Middle Ear Cholesteatoma

We previously reported the localization of interleukin 1 in the epithelial layer of human cholesteatomas. On the basis of other studies that showed interleukin 1 can stimulate fibroblasts and macrophages to produce collagenases and prostaglandins, we then proposed that interleukin 1 may play an important role in cholesteatoma-related bone resorption, also. Our immunocytochemical study involving more human cholesteatoma samples revealed the presence of interleukin 1 in bone cells and monocytes in the region of active bone destruction. In the present study, the effect of interleukin 1 on these cells found at the bone resorption site was examined. By radioimmunoassay, interleukin 1 was shown to stimulate the production of prostaglandin E2 by osteoblasts in vitro. Interleukin 1 also promoted the migration and multinucleation of bone marrow-derived monocytes. These osteoclast-like cells formed from monocytes contained tartrate-resistant acid phosphatase, and caused the resorption of the devitalized bone in vitro. Above findings suggest that interleukin 1 could cause the bone destruction in cholesteatomas, not only by stimulating the local bone cells, but also by recruiting monocytes for osteoclastic bone resorption.

Surgical Anatomy of the Guinea Pig Ear

The basic anatomy of the guinea pig ear is outlined as background for a description of two surgical approaches to the guinea pig temporal bone. These approaches provide access to the external, middle, and inner ear without significant blood loss or mortality. The superior approach, made by incision at the superior anterior attachment of the auricle and removing the lateral wall of the epitympanic space, exposes the round window, epitympanum, lateral canal, and external auditory canal, leaving the tympanic membrane intact. The inferior approach through the neck exposes the cochlea, Eustachian canal, horizontal and posterior semicircular canals, tympanic membrane, and ossicles.

Localization of interleukin-1 in human cholesteatoma

Recent studies by other investigators have shown that interleukin-1 (IL-1) promotes bone resorption by stimulating various cells. Interleukin-1 not only stimulates collagenase production by fibroblasts and macrophages, but also acts as an osteoclast-activating factor. In this study, IL-1 was localized in human cholesteatoma tissues using both immunoperoxidase and immunofluorescent-staining methods with specific monoclonal antibodies. Highly concentrated IL-1 was found in the epithelial layer and granulation tissue. More specifically, intense staining was seen in basal and spinous cells of the epithelial layer, and in fibroblasts and macrophages of the granulation layer. We also located IL-1 in the normal external ear canal skin; however, the intensity of the staining in the cholesteatoma epithelium was found to be stronger. The presence of IL-1 in the epithelial layer and granulation tissue of the cholesteatoma suggests that IL-1 from the stimulated keratinocytes of the cholesteatoma could be one factor responsible for the markedly increased bone resorption observed in cholesteatoma patients.

Intraoperative baer monitoring and hearing preservation in the treatment of acoustic neuromas

We treated 20 cases of acoustic neuromas in the last 2 1/2 years using the suboccipital approach with intraoperative monitoring of eighth nerve function in an attempt to preserve hearing. Total tumor removal was accomplished in 18 cases. Three tumors were small (less than 2 cm in size); 3 tumors were moderate sized (2 to 3 cm) and 14 tumors were large (greater than 3 cm). In 15 cases, all BAER components were lost during surgery. These patients had no postoperative hearing.

Experimental Aural Cholesteatoma Causing Bone Resorption

A series of experiments were carried out on 55 guinea pigs in four groups to study the conditions fostering bone resorbing epidermal cysts. The first group had free grafts of canal wall skin applied to the cochlea with and without talc application. The second group had canal skin flaps applied to the cochlea with and without subsequent talc application. The third group had talc applied either to the tympanic membrane or on the cochlea. The fourth group had a canal skin flap inserted into a mucosal pocket in the bulla. The animals were killed three to four months after surgery and the temporal bones were prepared for histology. Epidermal cysts were found at the cochlea in 8 of 55 animals. Cochlear fistulas were found in 6 of 55 animals. The fistulas were associated with epidermal cysts in three cases, otitis media in two cases, and talc granuloma in one case. These experiments show that migrating skin attached to a source of epithelium is capable of inducing bone resorption. Chronic foreign body granulomas and chronic sepsis are also capable of resorbing bone. These three conditions all produce a layer of undifferentiated connective tissue containing chronic inflammatory cells lying against the resorbing bone.

Bone resorption in cholesteatoma: Epithelial-mesenchymal cell interaction and collagenase production†

Clinical evidence has shown that chronic otitis media with cholestentoma causes greater bone resorption than otitis media without cholesteatoma. What is the role of the epithelium and its products on the morbidity of cholesteatoma? We have studied the mechanism of collagenase production in cultures of rat epidermal cells and skin fibroblast‐like cells under various conditions. The epithelial cells significantly induced mesenchymal cells to produce collagenase. We conclude that interaction between epithelial cells and fibroblast‐like cells enhances production of collagenase. This enhancement of proteolytic activity may be crucial in the series of molecular events resulting in bone resorption associated with cholesteatoma.

Results of conservative surgery for middle ear cholesteatoma

A retrospective study was carried out to analyze treatment results for cholesteatoma at the University of Iowa Hospitals and Clinics. All patients undergoing primary surgical treatment from January 1, 1969 to December 31, 1973 were followed through October 1976. Treatment failures were based on the occurrence of postoperative cholesteatoma. The probability of being disease free for periods up to five years after original surgery was then estimated for each type of operation.

Collagenase in Human Head and Neck Tumors and Rat Tumors and Fibroblasts in Monolayer Cultures

Invasive tumors must release collagenase to break down the surrounding host connective tissues. The cellular origin of this enzyme is still unclear. We used anticollagenase antibodies to localize collagenase in the human head and neck tumor and rat tumor tissues. Collagenase appeared to be localized in the tumor connective tissue stroma but not in tumor cells. The rat skin fibroblasts in monolayer culture treated with the rat tumor cell-conditioned medium demonstrated marked extranuclear and particulate staining. Fibroblasts without treatment showed no staining. Tumor cells in the culture also showed no staining. Assay of culture media demonstrated that only fibroblasts with the addition of the tumor cell-conditioned medium produced collagenase. These findings suggest the following: 1) collagenase is produced by fibroblasts which are harbored in the connective tissue stroma, but not by tumor cells; 2) cellular interaction between tumor cells and fibroblasts appears to be involved in breakdown of the host connective tissue for tumor cell invasion; and 3) tumor cells release soluble factors which stimulate production of collagenase by fibroblasts.

Collagenase activity in cultures of rat prostate carcinoma.

A specific collagenase (EC 3.4.24.3) has been found and purified from serum-free culture medium of 11095 epidermoid carcinoma of rat prostate. The molecular weight of this collagenase was estimated at 71 000 and the pH optimum was approx. 7. At 26 degrees C, the collagenase cleaved collagen at a site 3/4 the length from the N-terminus. At 37 degrees C, this collagenase degraded collagen to smaller peptides. The enzyme activity was inhibited by serum, cysteine and EDTA, but not by protease inhibitors. The presence of collagenase in rat tumor tissue suggests that this enzyme might play a significant role in tissue invasion by cancer cells.