Porta-caval fibrous connections - the lesser-known structure of intrahepatic connective-tissue framework: A unified view of liver extracellular matrix.

Knowledge about the connective-tissue framework of the liver is not systematized, the terminology is inconsistent and some perspectives on the construction of the hepatic matrix components are contradictory. In addition, until the last two decades of the 20th century, the connective-tissue sheaths of the portal tracts and the hepatic veins were considered to be independent from each other in the liver and that they do not make contact with each other. The results of the research carried out by Professor Shalva Toidze and his colleagues started in the 1970s in the Department of Operative Surgery and Topographic Anatomy at the Tbilisi State Medical Institute have changed this perception. In particular, Chanukvadze I showed that in some regions where they intersect with each other, the connective tissue sheaths of the large portal complexes and hepatic veins fuse. The areas of such fusion are called porta-caval fibrous connections (PCFCs). This opinion review aims to promote a systematic understanding of the hepatic connective-tissue skeleton and to demonstrate the hitherto underappreciated PCFC as a genuine structure with high biological and clinical significance. The components of the liver connective-tissue framework - the capsules, plates, sheaths, covers - are described, and their intercommunication is discussed. The analysis of the essence of the PCFC and a description of its various forms are provided. It is also mentioned that analogs of different forms of PCFC are found in different mammals.

Liver structural transformation after partial hepatectomy and repeated partial hepatectomy in rats: A renewed view on liver regeneration.

BACKGROUND: The phenomenon of liver regeneration after partial hepatectomy (PH) is still a subject of considerable interest due to the increasing frequency of half liver transplantation on the one hand, and on the other hand, new surgical approaches which allow removal of massive space-occupying hepatic tumors, which earlier was considered as inoperable. Interestingly, the mechanisms of liver regeneration are extensively studied after PH but less attention is paid to the architectonics of the regenerated organ. Because of this, the question "How does the structure of regenerated liver differ from normal, regular liver?" has not been fully answered yet. Furthermore, almost without any attention is left the liver's structural transformation after repeated hepatectomy (of the re-regenereted liver). AIM: To compare the architectonics of the lobules and circulatory bed of normal, re-generated and re-regenerated livers. METHODS: The livers of 40 adult, male, albino Wistar rats were studied. 14 rats were subjected to PH - the 1st study group (SG1); 10 rats underwent repeated PH - the 2nd study group (SG2); 16 rats were subjected to sham operation - control group (CG); The livers were studied after 9 months from PH, and after 6 months from repeated PH. Cytological (Schiff reaction for the determination of DNA concen-tration), histological (H&E, Masson trichrome, CK8 Immunohistochemical marker, transparent slides after Indian Ink injection, ), morphometrical (hepatocytes areas, perimeters and ploidy) and Electron Microscopical (Scanning Electron Microscopy of corrosion casts) methods were used. RESULTS: In the SG1 and SG2, the area of hepatocytes and their perimeter are increased compared to the CG (P < 0.05). However, the areas and perimeters of the hepatocytes of the SG1 and SG2 groups reveal a lesser difference. In regenerated (SG1) and re-regenerated (SG2) livers, the hepatocytes form the remodeled lobules, which size (300-1200 µm) exceeds the sizes of the lobules from CG (300-600 µm). The remodeled lobules (especially the "mega-lobules" with the sizes 1000-1200 µm) contain the transformed meshworks of the sinusoids, the part of which is dilated asymmetrically. This meshwork might have originated from the several portal venules (interlobular and/or inlet). The boundaries between the adjacent lobules (including mega-lobules) are widened and filled by connective tissue fibers, which gives the liver parenchyma a nodular look. In SG2 the unevenness of sinusoid diameters, as well as the boundaries between the lobules (including the mega-lobules) are more vividly expressed in comparison with SG1. The liver tissue of both SG1 and SG2 is featured by the slightly expressed ductular reaction. CONCLUSION: Regenerated and re-regenerated livers in comparison with normal liver contain hypertrophied hepatocytes with increased ploidy which together with transformed sinusoidal and biliary meshworks form the remodeled lobulli.

New corrosion cast media and its ability for SEM and light microscope investigation.

SEM of corrosion casts (CC) provides the opportunities to study the vessels and ducts in the phyllogenetic and ontogenetic (age-related) settings, as well as the pathogenesis, compensation, and sanogenesis in different diseases and experimental models. Along with the refinement of SEM CC, the requirements toward casting media (CM) as nontoxicity, low viscosity, quick polymerization, resistance to corrosion solutions, availability, and so on, gradually has developed. We aimed to adapt the sets widely used in dental practice toward the modern requirements to the CC. The following ratio of the components of Protacryl-M and Aycryl-C sets were used for the preparation CM-0.25 g MAYCRYL Powder +0.08 g Benzoyl Peroxide +5.0 ml Protacryl-M liquid component +0.2 Redont Colour (dye concentrate). The obtained solidifying mass was injected in the blood vessels and biliary ducts of the adult Wistar white rats. The SEM of CC of different organs' vascular networks, as well as a biliary tract, reveals that offered CM excellently replicates the forms and branching features of studied tubular structures of all sizes and gives the adequate imprinting of their luminal surfaces. Besides, CM may provide the replication of perivascular spaces and give the casts having no analogous in the appropriate literature. The CM prepared by us perfectly reproduces all possibilities of famous rubbers widely used for the casting of different vascular-ductular structures. Besides, it presents the new implications, which should be implemented in the profound research of the connective-tissue skeleton of different organs.