Cell inactivation

Sensing of encapsulation-induced physiological stress will help in the devising of synthesis procedures that will minimize cell inactivation during immobilization. 

The probable mechanism of action for all of the stable A -halamines involves direct contact of the microorganism with the combined A -halamine, followed by donation of a Cl" or Br" species to a receptor site within the cell, causing oxidation, and subsequent cell inactivation. Once the halogen content is exhausted through reaction with reducing agents, organic impurities. 

The last, minor point is specific to the measurements of cell inactivation reaction rates as they show a linear relationship with the initial bacteria concentration, a fact that should be considered when comparing results. 

Table 12.24. RBE and OER values for cell inactivation and induction of DSBs in V79-4 cells on the photon energy of the ultrasoft X rays, (de Lara et al. 2001) ...

Tilby MJ, Loverock PS (1983) Measurements of DNA double-strand break yields in E. coli after rapid irradiation and cell inactivation The effects of inactivation. Technique and anoxic radiosensitizers. Radiat Res 96 309-321... 

Although in most cases they have lower quantum yields for cell inactivation, they have other properties like improved solubility and stability, which makes them interesting as therapeutic substances. The metals used at least in experimental PDT include Zn, Pd, Sn, Ru, Pt, Lu, Gd, and Al. 

Gold alters the morphology and functional capabilities of human macrophages—possibly its major mode of action. As a result, monocyte chemotactic factor-1, interleukin-8, interleukin-IB production, and vascular endothelial growth factor are all inhibited. Intramuscular gold compounds also alter lysosomal enzyme activity, reduce histamine release from mast cells, inactivate the first component of complement, and suppress the phagocytic activities of polymorphonuclear leukocytes. Auranofin also inhibits release of prostaglandin E2 and leukotriene B4. 

Shimojo, N., Katsuki, T., Coligan, J.E., Nishimura, Y., Sasazuki, T., Tsunoo, H. et al. 1994. Identification of the disease-related T cell epitope of ovalbumin and epitope-targeted T cell inactivation in egg allergy. Int Arch Allergy Immunol 105(2) 155—161. 

Interleukin-2 Impairs proliferation of T-cells Inactivates cytokine... 

The specific cytotoxicity of Bi-anti-Tac has been blocked by excess of unlabelled anti-Tac but not by human IgG. Anti-Tac alone is unable to inhibit the proliferation or protein synthesis of most leukemic T-cell lines . Toxins conjugated to anti-Tac bound to the surface of the leukemic cells are poorly and slowly internalized into endosomes, and toxin conjugate of anti-Tac does not pass easily from endosome vehicles to the cytosol in order to kill the cells.a-Particles emitted from bismuth-212bound to the surface of the leukemic cells are much more effective cytotoxic reagents. Hits of one or two a-particles are sufficient for cell inactivation. The one-hour half-life of Bi makes it appropriate for rapid targetting of leukemic cells without prolonged exposure of the normal tissue. 

Hahn GM, Braun J, Her-Kedcar I (1975) Thermochemotherapy synergism between hyperthermia (42° 3°C) and adriamycin (or bleomycin) in mammalian cell inactivation. Proc Natl Acad Sci USA 72 937-940... 

FIGURE 23.1 Schematic of PD models of cell proliferation with irreversible cell inactivation. Plasma or biophase dmg concentrations (C) interact with cells (R), which are proliferating according to a growth model (g(R)), in an irreversible bimolecnlar manner (f(C)). 

First-order reaction kinetics, with one or two linear stages, have been reported for the sterilization of a range of microbial cells using CO2 (11,53-55). The presence of water is required for efficient sterilization (12,53,56). For example, Kumagai and coworkers (53) examined the sterilization of Saccha-romyces cerevisiae in an aqueous solution at 40°C and a pressure range of 4-15 MPa. At low water content, the sterilization rate increased with increasing content of water. At a sufficiently high water content, free water (not bound to the cells) existed in the system and the sterilization rate was almost constant with water content. The authors conclude the presence of dissolved CO2 in the aqueous-cell environment, and not system depressurization (which occurred at a rate of 8 MPa/h), was responsible for the inactivation of the microbial cells. Cell inactivation kinetics are difficult to compare across laboratories because the aqueous media is frequently not saturated with dissolved CO2 and the actual concentrations are not measured (44,51). 

B.B. Noodt, E. Kvam, H.B. Steen, J. Moan (1993). Primary DNA damage, HPRT mutation and cell inactivation photoinduced with various sensitizers in V79 cells. Photochem. PhotobioL, 58, 541-547. 

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