Matrilysin/matrix metalloproteinase-7(MMP7) cleavage of perlecan/HSPG2 creates a molecular switch to alter prostate cancer cell behavior.

Perlecan/HSPG2, a large heparan sulfate (HS) proteoglycan, normally is expressed in the basement membrane (BM) underlying epithelial and endothelial cells. During prostate cancer (PCa) cell invasion, a variety of proteolytic enzymes are expressed that digest BM components including perlecan. An enzyme upregulated in invasive PCa cells, matrilysin/matrix metalloproteinase-7 (MMP-7), was examined as a candidate for perlecan proteolysis both in silico and in vitro. Purified perlecan showed high sensitivity to MMP-7 digestion even when fully decorated with HS or when presented in native context connected with other BM proteins. In both conditions, MMP-7 produced discrete perlecan fragments corresponding to an origin in immunoglobulin (Ig) repeat region domain IV. While not predicted by in silico analysis, MMP-7 cleaved every subpart of recombinantly generated perlecan domain IV. Other enzymes relevant to PCa that were tested had limited ability to cleave perlecan including prostate specific antigen, hepsin, or fibroblast activation protein α. A long C-terminal portion of perlecan domain IV, Dm IV-3, induced a strong clustering phenotype in the metastatic PCa cell lines, PC-3 and C4-2. MMP-7 digestion of Dm IV-3 reverses the clustering effect into one favoring cell dispersion. In a C4-2 Transwell® invasion assay, perlecan-rich human BM extract that was pre-digested with MMP-7 showed loss of barrier function and permitted a greater level of cell penetration than untreated BM extract. We conclude that enzymatic processing of perlecan in the BM or territorial matrix by MMP-7 as occurs in the invasive tumor microenvironment acts as a molecular switch to alter PCa cell behavior and favor cell dispersion and invasiveness.

Bacteria associated with crabs from cold waters with emphasis on the occurrence of potential human pathogens.

A diverse array of bacterial species, including several potential human pathogens, was isolated from edible crabs collected in cold waters. Crabs collected near Kodiak Island, Alaska, contained higher levels of bacteria than crabs collected away from regions of human habitation. The bacteria associated with the crabs collected near Kodiak included Yersinia enterocolitica, Klebsiella pneumoniae, and coagulase-negative Staphylococcus species; the pathogenicity of these isolates was demonstrated in mice. Although coliforms were not found, the bacterial species associated with the tissues of crabs collected near Kodiak indicate possible fecal contamination that may have occurred through contact with sewage. Compared with surrounding waters and sediments, the crab tissues contained much higher proportions of gram-positive cocci. As revealed by indirect plate counts and direct scanning electron microscopic observations, muscle and hemolymph tissues contained much lower levels of bacteria than shell and gill tissues. After the death of a crab, however, the numbers of bacteria associated with hemolymph and muscle tissues increased significantly. Microcosm studies showed that certain bacterial populations, e.g., Vibrio cholerae, can be bioaccumulated in crab gill tissues. The results of this study indicate the need for careful review of waste disposal practices where edible crabs may be contaminated with microorganisms that are potential human pathogens and the need for surveillance of shellfish for pathogenic microorganisms that naturally occur in marine ecosystems.

Incus interposition. A 15-year report.

A 10- to 15-year follow-up study of patients with modeled incus interposition procedure for restoration of hearing reveals that hearing gains as reported in 1972 were sustained by long-term postoperative care despite resurgence of problems from negative middle ear air pressures.

Bilateral abductor paralysis: 30 years experience with arytenoidectomy.

Modifications of the technique originally reported in 1946 are presented, which may help in improving the percentage of successful decannulations. The importance of a change in the level of the vocal cord by this procedure is emphasized. The ten cautions to be followed are reviewed in doing this procedure.

Symposium: Methods of reconstruction in tympanoplasty. I. Management of fixation of malleolus head and incudal body in tympanoplasty.

Depending upon the presence or absence of stapedial mobility, treatment of ossicular fixation will vary. Methods and indication to preserve the fixed malleolar head and neck are discussed and positive indications for removal of the incus are enumerated. A description of various surgical techniques of interposition of the incus between the mobile malleus and stapes to relieve stapes fixation and restore continuity are described in detail.

Human antibody response to three meningococcal outer membrane antigens: comparison by specific hemagglutination assays.

Three cell surface antigens, protein, lipopolysaccharide, and polysaccharide, were purified from group B and group C strains of Neisseria meningitidis representing a variety of serotypes. Chemical analysis indicated that cross-contamination was on the order of 1%. Sensitization of sheep erythrocytes with these antigens resulted in highly specific passive hemagglutination assays for the three kinds of antigens. Paired human sera from several groups of individuals were tested by hemagglutination for antibody against each of the antigens. Patients with group B or C systemic meningococcal disease showed increases in antibody titer against all three kinds of antigens, but the antibody response to B polysaccharide was low compared with the response to C polysaccharide. Nasopharyngeal carriers of group B meningococci showed significant increases in titer only against the protein antigens, and noncarriers who received a C-polysaccharide vaccine had a specific response to the C polysaccharide. A given protein or lipopolysaccharide antigen reacted on the average equally well with either group B or C convalescent sera. These results suggest that all three antigens may play a role in the broad human immunity following natural infection.