Cochlear implant magnet extrusion with subsequent surgical replacement and restoration of full implant use without the need for device explantation.

Objective And Importance: We recount the unusual case of a young boy whose removable cochlear implant magnet extruded through the skin after becoming displaced after several episodes of direct but minor head trauma. This article outlines a course of clinical management that resulted in the successful re-implantation of a new magnet without infective sequelae and the need for device explantation.

Clinical Presentation: The child presented with recurrent erythema and swelling at the implant site.

High-risk adolescent injury prevention: the first program of its kind.

This article describes the history, development, and growth of Maryland's first hospital-based trauma prevention program. It details how the creators of the program partnered with multiple community agencies to provide a much-needed service for high-risk teens. The program has grown to include a variety of prevention education programs reaching people of all ages.

Transplanted mouse embryonic stem-cell-derived motoneurons form functional motor units and reduce muscle atrophy.

Prolonged muscle denervation resulting from motor neuron (MN) damage leads to atrophy and degeneration of neuromuscular junctions (NMJs), which can impart irreversible damage. In this study, we ask whether transplanted embryonic stem (ES) cells differentiated into MNs can form functional synapses with host muscle, and if so what effects do they have on the muscle. After transplantation into transected tibial nerves of adult mice, ES-cell-derived MNs formed functional synapses with denervated host muscle, which resulted in the ability to produce average tetanic forces of 44% of nonlesioned controls.

Functional properties of motoneurons derived from mouse embryonic stem cells.

The capacity of embryonic stem (ES) cells to form functional motoneurons (MNs) and appropriate connections with muscle was investigated in vitro. ES cells were obtained from a transgenic mouse line in which the gene for enhanced green fluorescent protein (eGFP) is expressed under the control of the promotor of the MN specific homeobox gene Hb9. ES cells were exposed to retinoic acid (RA) and sonic hedgehog agonist (Hh-Ag1.

Simian virus nomenclature, 1980.

Approximately 75 simian viruses, counterparts of other animal viruses, are recognized. Nomenclature of these isolates, in general, consists of an SV (simian virus) or SA (simian agent) numerical series with no attempt to group them according to virus families. The biologic characteristics of these viruses indicate they may be classified into recognized families and groups.

Chemical carcinogen alteration of SV40 virus induced transformation of normal human cell populations in vitro.

The frequency of simian papovirus 40 (SV40) induced transformation of human cells was enhanced after pretreatment with either napthylamine-2,N-methyl-N'-nitrosoguanidine (MNNG), N-acetyl-2-fluorenylacetamide (N-Ac-AAF), benzo[a]pyrene (BP), aflatoxin B1, propane sultone (PS), beta-propiolactone, 4-nitroquinoline oxide (4-NQO), methylmethane sulfonate (MMS) or diethyl nitrosamine (DEN). Posttreatment with 4-NQO, MMS, MNNG or DEN inhibited transformation; while posttreatment with either aflatoxin B1, beta-propiolactone or napthylamine-2 did not alter transformation similar to the action of N-Ac-AAF and BP. All carcinogens that altered transformation after pretreatment damaged cellular DNA.

Biochemical activation of aryl hydrocarbon hydroxylase activity, cellular distribution of polynuclear hydrocarbon metabolites, and DNA damage by polynuclear hydrocarbon products in human cells in vitro.

Carcinogenic polynuclear hydrocarbons [7,12-dimethylbenzanthracene, 3-methylcholanthrene, and benzo(a)pyrene] were added to human skin fibroblast cell cultures. Only benzo(a)pyrene at 10 microgram/ml or above induced mixed-function hydroxylase activity, altered cell proliferation kinetics, and caused DNA damage as measured by altered grain count and bromodeoxyuridine incorporation. 3-Methylcholanthrene at concentrations as high as 15 microgram/ml was ineffective.

Purification of infectious feline leukemia virus from large volumes of tissue culture fluids.

Feline leukemia virus from tissue culture fluids was concentrated 100 times by continuous-flow molecular filtration. Virus concentrates retained 100% of their original infectivity. Further purification was accomplished by a single sucrose density gradient centrifugation.

Preparation of cell-free feline oncornavirus-associated cell membrane antigen.

Cell-free feline oncornavirus-associated cell membrane antigen (FOCMA) was prepared from a feline lymphoblastoid cell line of tumor origin (FL-74). Membrane fractions, separated on sucrose density gradients, and papain-solubilized products were found to contain FOCMA as determined by their capacity to inhibit reference cytotoxic cat antisera.

Lymphocyte mitogen reactivity and enumeration of circulating B- and T-cells during feline leukemia virus infection in the cat.

Mitogen-induced blast transformation of peripheral blood lymphocytes and quantitative changes in circulating T- and B-cells were studied serially in cats inoculated with feline leukemia virus (FeLV). Concanavalin A-induced blast transformation sharply declined beginning at 5 weeks post inoculation (Pl) in FeLV-infected cats when compared to age-matched uninfected control cats. Similar but less consistent changes were seen in responses to pokeweed mitogen-induced stimulation.

Characterization of feline T-and B-lymphocytes and identification of an experimentally induced T-cell neoplasm in the cat.

Membrane markers of feline T- and B-lymphocytes were identified for further investigation of leukemogenesis in the cat. Feline T-cells formed spontaneous erythrocyte rosettes with guinea pig (GPE) and rat erythrocytes (RE). The receptors for GPE and RE were separate entities and expressed independently on lymphoid cell membranes.

Influence of glucocorticoid, estrogen, and androgen hormones on transformation of human cells in vitro by feline sarcoma virus.

Infection of human foreskin cells (D-550) by the Snyder-Theilen strain of feline sarcoma virus produced small but countable foci and demonstrated "single-hit" dose-response kinetics. Significant quantitative and qualitative enhancement of focus formation was observed when the glucocorticoid hormones, dexamethasone, hydrocortisone, cortisol acetate, and prednisolone were added to cell cultures (1.0 mug/ml) 24 hr postinfection.

Feline oncornavirus-associated cell membrane antigen. VI. Cytotoxic antibody in cats exposed to feline leukemia virus.

Feline leukemia virus (FeLV)-infected specific pathogen-free (SPF) cats, normal uninfected SPF cats, and healthy cats from leukemic households were tested for antibody reactive to the feline oncornavirus-associated cell membrane antigen (FOCMA)-containing target cell line FL-74 by microcytotoxicity and indirect membrane immunofluorescence. Of the infected SPF animals, 81% showed concordant reactivity for the two tests. In contrast, only 55% of the healthy cats known to be naturally exposed to FeLV for long periods showed such concordance.

Experimental oncornavirus vaccines in the cat.

An experimental approach to the immunoprophylatic control of feline oncornavirus-mediated diseases has included induction of antivirus immunity and antibodies to the feline oncornavirus-associated membrane (tumor) antigens. A suitable model for exploring the effectiveness of killed oncornavirus vaccines in the cat has been provided by the use of feline sarcoma virus. Immunization of seven pregnant queens over a 6-week period with ultraviolet light-inactivated Gardner-Arnstein feline sarcoma virus resulted in significant protection among 12 kittens challenged with a tumor-forming Dose 90 at 7 days of age.

Effects of steroid hormones in fetal bovine serum on plating ang cloning of human cells in vitro.

Fetal bovine sera from each of three different commercial sources were tested for their ability to support cloning of human fibroblastoid cells in vitro. Cloning efficiencies varied according to serum source. Serum (10 samples) from company A did not support growth, while sera (10 samples) from companies B and C provided adequate to excellent conditions for cloning and growth.

Influence of culture conditions of growth of FL-74 cells and feline oncornavirus cell membrane associated antigen production.

The FL-74 cell, a feline lymphoblastoid cell line derived from a tumor induced by leukemia virus, grows equally well in static suspension culture (plastic T-flask or silicone treated glass bottles) or in spinner culture. No growth was observed in unsiliconized glass bottles. Although feline leukemia virus production was nearly the same in FL-74 grown in each of the above types of vessel, the expression of the feline oncornavirus membrane associated antigen (FOCMA), as determined by membrane immunofluorescence, was more intense and more complete on cells grown in static suspension.

Feline oncornavirus-associated cell membrane antigen. V. Humoral immune response to virus and cell membrane antigens in cats inoculated with Gardner-Arnstein feline sarcoma virus.

Tumor growth responses in 5- to 6-week-old kittens inoculated with the Gardner-Arnstein strain of feline sarcoma virus exhibited three distinct pattern: 1) complete tumor regression or no detectable tumor growth in approximately one-third of 43 inoculated kittens, 2) rapid tumor progression which led to debilitation and death within 16.2 +/- 4.2 weeks following infection in an additional one-third, and 3) slow tumor growth or temporary regressions in the remaining third.

Antibody in cats to mammalian RNA tumor virus interspecies antigens.

The studies were undertaken to determine whether the cat, a mammalian species that carries xenotropic endogenous C-type virus(es) and in addition undergoes horizontally transmitted oncogenic C-type RNA tumor virus infections, responds immunologically to the mammalian C-type virus interspecies antigens. Sera from normal cats and from cats with spontaneous or virus-induced neoplasms were examined for antibodies to interspecies antigen antigen by complement-fixation inhibition, by inhibition of the paired radioiodine-labeled antibody technique (PRILAT inhibition), and by two-step radioimmunoelectrophoresis. Using three separate complement-fixation inhibition systems designed to detect antibodies to interspecies antigen(s), 23 of 23 sera from tumor-bearing cats and 24 of 31 sera from normal cats were positive in both systems.

Feline oncornavirus-associated cell membrane antigen. IV. Antibody titers in cats with naturally occurring leukemia, lymphoma, and other diseases.

Cats with naturally occurring leukemia and lymphoma had low or negative humoral antibody titers to the feline oncornavirus-associated cell membrane antigen (FOCMA). Geographic differences were seen in the relative frequencies of various forms of lymphoproliferative neoplasms. Lymphatic leukemia and thymic lymphoma were most common in Boston, whereas alimentary lymphoma was most frequent in Glasgow.

Feline oncornavirus-associated cell membrane antigen. II. Antibody titers in healthy cats from household and laboratory colony environments.

Antibody titers to the feline oncornavirusassociated cell membrane antigen (FOCMA) were determined for 447 healthy cats from laboratory colony and household environments. Only 2.7 percent of 221 cats from colony environments were antibody positive as compared to 50.

Complement-fixation-inhibition as a test for antibodies in cats and humans to C-type RNA tumor virus antigen.

The complement-fixation-inhibition (CFI) test was evaluated as a means of detecting humoral antibodies in cat sera and in human sera to mammalian C-type RNA virus interspecies antigen(s). CFI antibody titers of greater than or equal 1:2 were detected in sera from all tumor bearing (23) and normal cats (23), however, sera from most germ free cats were negative. When the same cat sera were tested for blocking antibody by the paired radioiodine labeled antibody technique the correlation between the radioimmune assay and CFI tests was 85%.

Alterations of enzymes associated with plasma membranes and cellular organelles during infection of CV-1 cells with Yaba tumor poxvirus.

The formation of cellular aggregates (foci) in CV-1 cells following infection with Yaba tumor poxvirus is dependent upon cell passage level, temperatue of incubation, and calcium concentration in the medium. Resistance of older cells can be reversed by maintaining calcium at 0.1 mM or by adding cortisone acetate (1 mug/ml), hydrocortisone, or estradiol-17beta to the cultures.