The antitumor effect of magnetic nanodisks and DNA aptamer conjugates.

Here we describe a method of forming large arrays (up to 10(9) pieces) of free magnetic Ni-nanodisks 50 nm thick coated on both sides with layers of 5 nm thick Au. The antitumor effect of the magnetic nickel gold-coated nanodisks and DNA aptamer conjugates was evaluated in vivo and in vitro. Under the influence of rotating magnetic field, the studied nanodisks can cause the death of Ehrlich ascites carcinoma cells.

Use of Grotenhuis perforator in endoscopic third ventriculostomy and cyst fenestration.

We performed a retrospective review of consecutive patients at our institution who underwent endoscopic third ventriculostomy (E3 V) or fenestration of intraventricular cysts using the Grotenhuis endoscopic perforator. The procedure was performed on 23 patients between 2001 and 2006, and included 20 E3Vs and three intraventricular cyst fenestrations. The Grotenhuis perforator was effective in accomplishing a fenestration with multiple attempts. When the floor of the third ventricle was translucent, the perforator was effective with the least amount of effort. The instrument was less effective and additional instruments were necessary in patients with arachnoid cysts or when the floor of the third ventricle was thick. The main advantage in using the Grotenhuis perforator was in displacing the floor of the third ventricle away from the basilar artery during perforation. No basilar artery injury or other serious complications occurred in patients who underwent E3 V or cyst fenestration using the Grotenhuis perforator.

Determination of ototoxicity of common otic drops using isolated cochlear outer hair cells.

OBJECTIVES: Otic drops are commonly used not only for otitis externa, but also for otorrhea in the presence of tympanostomy tubes or tympanic membrane perforations. Many studies have demonstrated the ototoxicity of common otic preparations such as Cortisporin otic drops (Monarch Pharmaceuticals, Bristol, TN). The purpose of this study was to assess the relative ototoxicity of common otic preparations by direct exposure to isolated cochlear outer hair cells (OHCs). METHODS: OHCs from adult chinchilla cochlea were exposed to standard bathing solution (control), acetic acid, Acetasol HC (Alpharma USPD Inc., Baltimore, MD), Gentacidin (CIBA Vision Ophthalmics, Atlanta, GA), and Tobradex (Alcon, Fort Worth, TX). The cells were observed using an inverted microscope, and the images were recorded in digital still-frame and video, and analyzed on the Image Pro-Plus 3.0 program (Media Cybernetics, Silver Spring, MD). RESULTS AND CONCLUSIONS: As measured by time to cell death and change in morphology of OHCs, acetic acid with or without hydrocortisone was most toxic to OHCs. Cortisporin was more cytotoxic than gentamicin and Tobradex.

TrfA-dependent inner membrane-associated plasmid RK2 DNA synthesis and association of TrfA with membranes of different gram-negative hosts.

TrfA, the replication initiator protein of broad-host-range plasmid RK2, was tested for its ability to bind to the membrane of four different gram-negative hosts in addition to Escherichia coli: Pseudomonas aeruginosa, Pseudomonas putida, Salmonella enterica serovar Typhimurium, and Rhodobacter sphaeroides. Cells harboring TrfA-encoding plasmids were fractionated into soluble, inner membrane, and outer membrane fractions. The fractions were subjected to Western blotting, and the blots were probed with antibody to the TrfA proteins. TrfA was found to fractionate with the cell membranes of all species tested. When the two membrane fractions of these species were tested for their ability to synthesize plasmid DNA endogenously (i.e., without added template or enzymes), only the inner membrane fraction was capable of extensive synthesis that was inhibited by anti-TrfA antibody in a manner similar to that of the original host species, E. coli. In addition, although DNA synthesis did occur in the outer membrane fraction, it was much less extensive than that exhibited by the inner membrane fraction and only slightly affected by anti-TrfA antibody. Plasmid DNA synthesized by the inner membrane fraction of one representative species, P. aeruginosa, was characteristic of supercoil and intermediate forms of the plasmid. Extensive DNA synthesis was observed in the soluble fraction of another representative species, R. sphaeroides, but it was completely unaffected by anti-TrfA antibody, suggesting that such synthesis was due to repair and/or nonspecific chain extension of plasmid DNA fragments.

Identification of a potential membrane-targeting region of the replication initiator protein (TrfA) of broad-host-range plasmid RK2.

Plasmid RK2 codes for two species of the replication initiator protein TrfA (33 and 44 kDa). Both polypeptides are strongly associated with membrane fractions of Escherichia coli host cells (W. Firshein and P. Kim, Mol. Microbiol. 23, 1-10, 1997). We investigated the role of a 12-amino-acid hydrophobic region (HR) in the membrane association of TrfA. Epitope-tagged polypeptide fragments of TrfA that contained HR were expressed and found to be associated with membrane fractions. Site-directed mutagenesis of trfA revealed that changes of specific amino acids in HR can affect both TrfA association with the membrane and its ability to support replication of an RK2 oriV plasmid in vivo. These results are consistent with the hypothesis that membrane association of TrfA is functionally relevant and that the HR region of TrfA is involved in membrane association and DNA replication in vivo.

Isolation of an inner membrane-derived subfraction that supports in vitro replication of a mini-RK2 plasmid in Escherichia coli.

Previous results have demonstrated that the inner, but not the outer, membrane fraction of Escherichia coli is the site of membrane-associated DNA replication of plasmid RK2, a broad-host-range plasmid capable of replication in a wide variety of gram-negative hosts (K. Michaels, J. Mei, and W. Firshein, Plasmid 32:19-31, 1994). To resolve the inner membrane replication site further, the procedure of Ishidate et al. (K. Ishidate, E. S. Creeger, J. Zrike, S. Deb, G. Glauner, T. J. MacAlister, and L. I. Rothfield, J. Biol. Chem. 261:428-443, 1986) was used to separate the inner membrane into a number of subfractions, of which only one, a small subfraction containing only 10% of the entire membrane, was found to synthesize DNA inhibited by antibody prepared against the plasmid-encoded initiation protein TrfA. This is the same subfraction that was also found to bind oriV and TrfA to the greatest extent in filter binding assays (J. Mei, S. Benashski, and W. Firshein, J. Bacteriol. 177:6766-6772, 1995).

Glucosamine, chondroitin, and manganese ascorbate for degenerative joint disease of the knee or low back: a randomized, double-blind, placebo-controlled pilot study.

OBJECTIVE: A 16-week randomized, double-blind, placebo-controlled crossover trial of a combination of glucosamine HCl (1,500 mg/day), chondroitin sulfate (1,200 mg/day), and manganese ascorbate (228 mg/day) in degenerative joint disease (DJD) of the knee or low back was conducted. METHODS: Thirty-four males from the U.S. Navy diving and special warfare community with chronic pain and radiographic DJD of the knee or low back were randomized. A summary disease score incorporated results of pain and functional questionnaires, physical examination scores, and running times. Changes were presented as a percentage of the patient's average score. RESULTS: Knee osteoarthritis symptoms were relieved as demonstrated by the summary disease score (-16.3%; p = 0.05), patient assessment of treatment effect (p = 0.02), visual analog scale for pain recorded at clinic visits (-26.6%; p = 0.05) and in a diary (-28.6%; p = 0.02), and physical examination score (-43.3%; p = 0.01). Running times did not change. The study neither demonstrated, nor excluded, a benefit for spinal DJD. Side effect frequency was similar to that at baseline. There were no hematologic effects. CONCLUSIONS: The combination therapy relieves symptoms of knee osteoarthritis. A larger data set is needed to determine the value of this therapy for spinal DJD. Short-term combination therapy appears safe in this setting.