RESUMEN
We report the results of an interdisciplinary collaboration formed to assess the sterilizing capabilities of the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP). This newly-invented source of glow discharge plasma (the fourth state of matter) is capable of operating at atmospheric pressure in air and other gases, and of providing antimicrobial active species to surfaces and workpieces at room temperature as judged by viable plate counts. OAUGDP exposures have reduced log numbers of bacteria, Staphylococcus aureus and Escherichia coli, and endospores from Bacillus stearothermophilus and Bacillus subtilis on seeded solid surfaces, fabrics, filter paper, and powdered culture media at room temperature. Initial experimental data showed a two-log10 CFU reduction of bacteria when 2 x 10(2) cells were seeded on filter paper. Results showed > or = 3 log10 CFU reduction when polypropylene samples seeded with E. coli (5 x 10(4)) were exposed, while a 30 s exposure time was required for similar killing with S. aureus-seeded polypropylene samples. The exposure times required to effect > or = 6 log10 CFU reduction of E. coli and S. aureus on polypropylene samples were no longer than 30 s. Experiments with seeded samples in sealed commercial sterilization bags showed little or no differences in exposure times compared to unwrapped samples. Plasma exposure times of less than 5 min generated > or = 5 log10 CFU reduction of commercially prepared Bacillus subtilis spores (1 x 10(5)); 7 min OAUGDP exposures were required to generate a > or = 3 log10 CFU reduction for Bacillus stearothermophilus spores. For all microorganisms tested, a biphasic curve was generated when the number of survivors vs time was plotted in dose-response cures. Several proposed mechanisms of killing at room temperature by the OAUGDP are discussed.
Asunto(s)
Bacillus subtilis/crecimiento & desarrollo , Escherichia coli/crecimiento & desarrollo , Geobacillus stearothermophilus/crecimiento & desarrollo , Staphylococcus aureus/crecimiento & desarrollo , Esterilización/métodos , Recuento de Colonia Microbiana , Relación Dosis-Respuesta en la Radiación , Óxidos de Nitrógeno/química , Ozono/química , Papel , Polipropilenos , Esporas/crecimiento & desarrolloRESUMEN
Interferon (IFN) is a protein with antiviral activity that has been shown to inhibit the growth of many different types of cells. We have measured the IFN sensitivity of nine cell cultures isolated from patients with squamous cell carcinoma and one with malignant melanoma of the head and neck. Normal-appearing fibroblast cultures isolated from these tissues appear quite sensitive to the antiviral effects of IFN. When the encephalomyocarditis virus yield reduction assay is used, these diploid cells are as sensitive to IFN-alpha as are newborn foreskin fibroblast cultures. A similar antiviral effect is seen with IFN-gamma. These cells are relatively insensitive to the antigrowth effect of both IFN preparations as measured by 3H thymidine incorporation and direct observations of cell growth. This is the same relative sensitivity as fibroblasts derived from normal patients. Since these cells are at least 100 times less sensitive to the antigrowth action of the IFNs, it appears unlikely that the IFNs play a significant role in the control of normal fibroblast growth, in contrast to the sensitivity of malignant cell lines.
Asunto(s)
Carcinoma de Células Escamosas/patología , Neoplasias de Cabeza y Cuello/patología , Interferón Tipo I/farmacología , Interferón gamma/farmacología , Melanoma/patología , Línea Celular , Células Cultivadas , Virus de la Encefalomiocarditis , Fibroblastos/efectos de los fármacos , Humanos , Técnicas In Vitro , OrthomyxoviridaeRESUMEN
The physiologic measurements of a subpopulation of mononuclear cells derived from head and neck lymphoid tissues are similar to those of dendritic cells are described. Dendritic cells are a subpopulation of bone marrow-derived leukocytes that were originally identified in rodents and now described in man as having central control of T-lymphocyte functions. We describe a technique for the enrichment of dendritic cells obtained from tonsils utilizing a bovine serum albumin (BSA) gradient and note that they have the light and electron microscopic appearance of dendritic cells. The measured oxidative mitogenic response and interferon-gamma production in complete leukocyte cultures was compared with BSA gradient-separated preparations. The denser cells, comprised mostly of normal appearing lymphocytes, would not undergo a mitogenic response nor produce normal amounts of interferon when stimulated unless the dendritic cell-rich, less-dense fraction, was added back. The dendritic cells derived from tonsils seem to behave as a potent accessory cell for these T-lymphocyte-associated functions.