Coagulative necrosis

2a Coagulative Necrosis. In coagulative necrosis, the gross and microscopic architecture of the necrotic tissue are still recognizable (at least to an extent). It should soon become clear that coagulative necrosis often precedes the other types 

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Trichloroacetic Acid (TCA) causes precipitation of proteins and coagulative necrosis of epidermal cells [4]. The extent of damage is indeed concentration dependent. Concentrations range from 10 to 50%. Superficial TCA peeling is induced by concentrations of 10-30% whereas higher concentrations cause medium depth or deep peeling. The combination of salicylic acid followed by TCA 10-15% induces superficial wounding. 

Coagulative necrosis limited to superficial proteins of epidermal cells... 

In the work of Samuelsson and Jonsson,86 thirty lungs from 26 healthy young pigs, weighing 20 to 30 kg, were subjected to ECT. In most experiments, 8-10 V and 50 to 70 mA were used and platinum electrodes were employed. Both anodic and cathodic sites showed coagulation necrosis and thrombosis in the vessels when examined microscopically. The lesions healed with fibrotic scarring. 

In ischemic episodes such as occur in myocardial infarction, lack of oxygen forces cells to rely on anaerobic glycolysis, which increases production of lactic add The consequent intracellular acidosis can cause proteins to denature and precipitate, leading to coagulation necrosis. 

In a myocardial infarction (MI), myocytes swell as the membrane potential collapses and the I cell gets leaky. Enzymes are released from the damaged tissue, and lactic acidosis contributes to protein precipitation and coagulation necrosis. 

Hepatic Effects. No studies were located regarding hepatic effects of 1,2-diphenylhydrazine in Humans. Chronic oral administration of 1,2-diphenylhydrazine produced degenerative alterations the liver of rats (fatty metamorphosis) and mice (coagulative necrosis) (NCI 1978). 

Survival was reduced in groups of rats receiving 90 mg/l /day for 13 weeks by gavage, and qU oplasmic vacuolization of hepatoqU es was increased in exposed males. In mice cen-trilobular coagulative necrosis and/or multifocal subchronic inflammation of the liver occurred at doses up to 1200mg/kg. ... 

Myocardial infarction. An area of coagulation necrosis in a tissue resulting from local ischemia in the heart. 

No treatment-related gross or histopathological lesions in the liver were observed in rats in the chronic experiment by NTP (1986), but dosed male mice had increased coagulative necrosis and hepatocytomegaly, along with increased incidences of hepatocellular adenomas and carcinomas (see Section 2.2.2.8 on carcinogenicity). Female mice, however, did not have treatment-related lesions in the liver. The highest dose (500 mg/kg/day) is indicated as a NOAEL for liver effects in rats, while the low dose (250 mg/kg/day) is indicated as a LOAEL for non-neoplastic liver lesions in... 

The slides are checked for inflammatory signs, such as edema, leukocytic infiltration or foci of coagulative necrosis. 

Figure 16.6. The four primary types of necrosis. (A) Coagulative. On the cut surface of this canine kidney, there is a dark red, wedge-shaped area of coagulative necrosis caused by blockage of the blood supply to the area (infarction). The pale areas are older infarcts. (B) Caseous. This bovine lymph node contains a large whitish, cheese-like area of caseous necrosis characterized by loss of the normal tissue architecture. (C) Liquefactive necrosis, equine brain. There are two large areas of liquefaction with extensive loss of brain tissue. (D) Fat necrosis, bovine abdominal fat. Necrotic fat is firm and chalky white and often becomes mineralized. See color insert.

Figure 16.7. Microscopic appearance of necrosis. (A) Coagulative necrosis in a virally infected avian liver. Hepatocytes in the lower half of the photo are in various stages of necrosis, with small, pyknotic or fragmented nuclei and increased cytoplasmic eosinophilia. (B) Necrotic cells in immune-mediated skin disease, canine. The central cell has a pyknotic nucleus and intensely eosinophilic cytoplasm, while the cells at lower left and upper left are injured and swollen. The smaller cells are neutrophils. See color insert.

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