Necrosis definition

Injury to important primary-producer species constituting forest ecosystems is not limited to California. In the eastern United States, a disease called emergence tipbum of eastern white pine was related to ozone by Berry and Ripperton. Occurrence of similar symptoms on the same species in eastern Canada could not be definitely related to ozone by Linzon.- The disease is characterized by bands of necrosis initiated in the semimature tissue of elongating needles the necrosis spreads to the needle tip. In other studies with ozone fumigations at 0.07 ppm for 4 h or 0.03 ppm for 48 h, the tipbum appeared additional symptoms were silvery or chlorotic flecks and chlorotic mottling. - ... 

These two definitions reflect two sides of the same situation. In this book, the term critical effect(s) will be used for the hazard/effect considered as being the essential one(s) for the purpose of the risk characterization, e.g., for the establishment of a health-based guidance value, permissible exposure level, or Reference Dose. It should be noted that the critical effect could be a local as well as a systemic effect. It should also be recognized that the critical effect for the establishment of a tolerable exposure level is not necessarily the most severe effect of the chemical substance. For example, although a substance may cause a serious effect such as liver necrosis, the critical effect for the establishment of, e.g., an occupational exposure limit could be a less serious effect such as respiratory tract irritation, because the irritation occurs at a lower exposure level. 

In a study of workers exposed to white phosphorus for intermediate durations in three fireworks plants, 2 of 44 workers developed definite cases of phossy jaw (Ward 1928). These cases, described as slight necrosis of the lower jaw, took up to 2 years for recovery. In the same study, 13 of 27 workers exposed to white phosphorus for chronic durations developed necrosis of the upper and/or lower jaw, ranging from slight to severe 2 of the 13 workers developing phossy jaw died from complications related to the necrosis. This study and several case reports discuss the progression of symptoms during the development of phossy jaw (Heimann 1946 Hughes et al. 1962 Kennon and Hallam 1944). It is likely that the development of necrosis of the jaw in workers exposed to airborne white phosphorus resulted from the local action of phosphorus on the oral cavity. This information is discussed in detail in Section 2.2.2.2. 

Histopathological features of white matter lesions include diffuse myelin pallor (sparing the U-fibers, that are supplied by cortical branches), astrocytic gliosis, widening of perivascular spaces, and loss of oligodendrocytes leading to rarefaction, spongiosis, as well as loss of myelin and axons without definite necrosis, which has also been described as incomplete white matter infarction, which may finally... 

Abstract Considering the presence of multiple types of cell death induced by chemicals, it is important to determine a definitive strategy for the exploration of new highly tumor-selective compounds. The screening of highly selective compounds should be performed before the identification of the type of cell death (either apoptosis, autophagy, or necrosis) and the cell death induction mechanism. The tumor specificities of heterocyclic compounds and the type of cell death induced by them are summarized. 

FIGURE 18.14 Dose intensity meta-analysis for doxorubicin in patients with osteosarcoma. Each bubble represents a separate clinical trial and the size of the bubble is proportional to the number of patients treated during the trial. Doxorubicin was administered prior to definitive surgical resection and effect is >90% necrosis of tumor in the resected specimen. Dose intensity or dose rate is measured in mg/m /week. (Reproduced with permission from Smith MA, Ungerleider RS, Horowitz ME, Simon R. J Natl Cancer Inst 1991 83 1460-70.)... 

The binding of drug to tissue is usually reversible. In some cases, however, there is covalent binding, which by definition is not reversible. This applies to drug or metabolite and could be important because it could be related to toxicity. " A good correlation has been reported in animals between the degree of covalent binding to hepatic protein and the severity of hepatic necrosis of paracetamol, isoniazid, adriamycin, and furosemide. " ... 

Following reports of colonic necrosis, the Pharmaceutical Affairs Bureau of Japan has revised the product information for enemas of polystyrene sulfonate cation exchange resin suspension in sorbitol solution for potassium removal (31). Although a causal relation has not been established definitively, the Bureau has decided that sorbitol solution should not be used for enemas of sodium polystyrene sulfonate cation exchange resins. 

Definition and differentiation of acute versus chronic papillary necrosis lesion... 

By definition, papillary necrosis represents the development of irreversible damage within the parenchyma of the renal papillae. The papillae of the kidney contain the tip portions of the long loops of Henle, together with the terminal portions of the collecting duct complexes, which open in to the minor calyces. The minor calyces of the kidneys representing the first location in the upper renal outflow tract into which mine is collected before it travels into the renal pelvis and into the urinary bladder via the ureters. 

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