Cell damage characterization

Intracerebroventricular injection of kainic acid has been shown to result in a well-characterized pattern of neuronal cell damage. In the hippocampus, kainic acid causes a selective lesion of the CA3 pyramidal neurons, an area rich in KA1 and GluR6 receptors. The lesion does not compromise passing axons, which is why this type of (excitotoxic) lesion is often referred to as axon-sparing . Kainic acid injection into the hippocampus also leads to epileptiform discharges in cells normally innervated by the damaged pyramidal neurons. 

Moderately damaged cells were characterized by the presence of several, often exceedingly large, crystalloids in the chloroplast stroma (Fig. U, 5). The crystalline bodies occurred... 

Despite the variability found in the different types of cancer including causes, symptoms, prognosis and treatments, a general statement can be made cancer is a genetic disease. Cancer cells are characterized by the presence of damage/mutations on one or more genes leading to unnatural function. 

These bioreactors are characterized by low levels of cell damage and can also be operated in perfusion mode. However, the main limitation of this type of equipment is related to its scale-up air-lift bioreactors up to only 5000 L have been described so far. 

The progressive course of cell damage through to cell death is mainly characterized by two biochemical metabolic processes (1.) oxidative stress and (2.) disruption of intracellular Ca homoeostasis. These two processes interact, so that the oxidative stress induces the disruption of calcium homoeostasis there are also, however, other reciprocal actions/effects involving further cellular metabolic processes. (27)... 

Cysteine proteases, called calpains, are known to be activated by sustained elevations in intracellular free calcium. Once activated, calpains degrade the cytoskeleton, transmitter and membrane channels, and metabolic enzymes (Hou and MacManus 2002 Mattson 2003 Nicholls 2004). Functionally, calpains have been characterized as pivotal mediators of both active necrotic cell death and PCD (Wang 2000) following cell-damaging stressors and insults such as soman exposure, excitotoxic challenges, toxins, free radicals, UV radiation, acute hypoxia, traumatic brain injury, cytokines, heat, and in chronic neurodegenerative conditions (Fischer et al. 1991 Caner et al. 

The antioxidants or quenchers of free radicals are known to minimize skin photoaging and the protective action of sun screens correlates closely to their free radical scavenging activity [49,50]. This prompted us to use the prevention of photodynamic yeast cell damage to comparatively investigate the protective activity of the four hydroxycoumarins esculin, esculetin, fraxin and fraxetin, and a widely used sun screen p-aminobenzoic acid (PABA). We applied the same test to characterize the protective activity of four Fraxinus ornus bark preparations containing these coumarins in different concentrations and to examine the activity of caffeic acid (16), a minor constituent of these preparations [51]. 

The spectmm of DILI is highly variable, ranging from abnormalities in liver enzyme levels to fulminant hepatic failure resulting in liver transplantation or death. The predominant form of DILI is acute hepatocellular injury, representing up to 90% of cases (Larrey 2000). This type of hepatic damage, which is usually characterized by an initial early increase in ALT levels, manifests itself as cell death, characterized as either zonal or nonzonal, in the form of necrosis and/or... 

Oteri, G. et al., Evaluation of the use of two human cell lines for okadaic acid and DTX-1 determination by cytotoxicity assays and damage characterization, Nat. Toxins, 6, 197, 1998. 

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