Necrogenic Action of Carbon Tetrachloride in the Rat: A Speculative Mechanism Based on Activation

○ Context.-Cirrhosis is widely regarded as being irreversible. Recent studies have demonstrated that fibrosis may decrease with time in humans and experimental animals if the disease activity becomes quiescent. The histologic appearance of regressing cirrhosis in the human has not been described in detail. Objectives.-To define histologic parameters that indicate regression of cirrhosis and to provide an interpretation of how regression occurs from a histologic point of view. Design.-A patient who underwent a series of biopsies that showed apparent regression of hepatitis B cirrhosis is presented. In addition, 52 livers removed at transplantation having cirrhosis or incomplete septal cirrhosis were graded for histologic parameters that suggest progression or regression of fibrosis. Progression parameters were steato-hepatitis, inflammation, bridging necrosis, and piecemeal necrosis. The regression parameters (collectively called the hepatic repair complex) were delicate perforated septa, isolated thick collagen fibers, delicate periportal fibrous spikes, portal tract remnants, hepatic vein remnants with prolapsed hepatocytes, hepatocytes within portal tracts or splitting septa, minute regenerative nodules, and aberrant parenchymal veins. Results and Conclusions.-Regression parameters were found in all livers and were prominent in the majority. Livers with micronodular cirrhosis, macronodular cirrhosis, and incomplete septal cirrhosis demonstrate a histologic continuum. A continuum of regressive changes was also seen within individual livers. These appearances allow one to understand visually how fibrous regions of hepatic parenchyma can be returned toward a normal appearance. Many examples of incomplete septal cirrhosis could be the product of regressed cirrhosis.

Regression of human cirrhosis. Morphologic features and the genesis of incomplete septal cirrhosis.

https://aasldpubs.onlinelibrary.wiley.com/doi/pdf/10.1002/hep.1840030118

Is Cirrhosis of the Liver Experimentally Produced by CC14 an Adequate Model of Human Cirrhosis

https://www.gastrojournal.org/article/S0016-5085(82)80126-1/pdf

High Yield Micronodular Cirrhosis in the Rat

Animal models of hepatic fibrosis provide a means to study the cell and molecular mediators of fibrosis in a serial manner during both progression and recovery. Several approaches to induction of fibrosis have been described. Of these, CCl(4) intoxication in rats and mice is probably the most widely studied. In addition, the CCl(4) model is the best characterized with respect to histological, biochemical, cell, and molecular changes associated with the development of fibrosis. CCl(4) can be given intraperitoneally or by oral gavage; it induces zone III necrosis and hepatocyte apoptosis with associated hepatic stellate cell activation and tissue fibrosis. With repetitive dosing CCl(4) can be used to induce bridging hepatic fibrosis (4 wk of twice-weekly dosing), cirrhosis (8 wk of twice-weekly dosing) and advanced micronodular cirrhosis (12 wk of twice-weekly dosing). In addition, for each of these models spontaneous recovery from fibrosis can be studied after cessation of dosing. Mechanistic studies using gene knockout and transgenic animals can also be established using CCl(4). Together these models have provided unparalleled insights into the mechanisms underlying hepatic fibrosis.

Modeling liver fibrosis in rodents

Carbon tetrachloride cirrhosis in relation to liver regeneration

The pathology of rhinosporidiosis

Liver changes in exophthalmic goitre

Massive necrosis (“toxic infarction”) of the liver following intra‐portal administration of poisons

: Decline of bee pollinators results in insufficient crop pollination, lowering the quality, and quantity of crop yields. In Sri Lanka, there is a lack of research on the importance of local bees in sesame pollination. The current study investigated the role of Sri Lankan native bees in pollinating sesame and increasing crop productivity. The research was carried out at Meewatura Farm, located in the Kandy District of the University of Peradeniya, Sri Lanka. Three pollination trials were conducted to determine the contribution of bees to enhance seed number, weight, and germinability of sesame, selecting 100 sesame flower buds randomly for each trial. One set of flowers buds was covered to prevent bee visits; another set was kept open to enable bee visits, while the third set was pollinated by hand. h). Significant differences ( p < 0.05) in seed number, seed weight, and seed germinability were detected among the three trials. Open flowers had significantly higher seed number ( p = 0.0001) and seed germinability ( p = 0.0001) than covered flowers. Although there was no significant difference in seed weight between seeds produced from open flowers and covered flowers, the seed weight of hand-pollinated flowers was significantly higher than the other two treatments ( p = 0.0001). This pioneering study highlights the role of native bees of Sri Lanka to enhance production in S. indicum in terms of seed number and quality.

http://cjs.sljol.info/articles/10.4038/cjs.v51i1.7976/galley/6433/download/

W. A. E. Karunaratne

Papers

Carbon tetrachloride cirrhosis in relation to liver regeneration

The pathology of rhinosporidiosis

Liver changes in exophthalmic goitre

Massive necrosis (“toxic infarction”) of the liver following intra‐portal administration of poisons

Native Sri Lankan bees enhance pollination of sesame, Sesamum indicum