Growth and differentiation of adult rat hepatocytes regulated by the interaction between parenchymal and non-parenchymal liver cells

We have devised a medium which supports the continuous growth of hepatocytes without losing their replicative potential and differentiation capacity for a longer period. The medium HCGM, contains four key substances in addition to foetal bovine serum. They are epidermal growth factor, nicotinamide, ascorbic acid 2-phosphate and dimethylsulphoxide. When a non-parenchymal cell fraction containing small hepatocytes and non-parenchymal cells was cultured in HCGM, small hepatocytes grew clonally and differentiated into cells expressing either mature hepatocyte marker proteins or biliary cell marker proteins. Thus, for the first time, we showed the presence of a small compartment of bipotent and highly replicative clonogenic hepatocytes in the rat adult liver. HCGM also supported the growth of stellate cells (Ito cells) which were in the original preparation, suggesting the important role of stellate cells for the successful cultivation of hepatocytes. Together, these results suggest that a microenvironment is produced as a result of cooperative interactions between hepatocytes and stellate cells: one which stimulates the growth and differentiation of clonogenic hepatocytes.     

Low-grade fibromyxoid sarcoma arising in the big toe

Low-grade fibromyxoid sarcoma (LGFMS) is a rare tumor. Reported herein is a case of LGFMS arising in the big toe. The patient was a 58-year-old man who underwent excision of the tumor. The tumor was well-demarcated. Histologically, there were proliferating spindle-shaped tumor cells arranged in a whorled growth pattern, and the stroma showed hyalinized collagen bundles and a myxoid matrix. Nuclear mitotic figures were conspicuous in part. A large rosette-like structure with hyalinized stroma was found, which is characteristic of LGFMS. The differential diagnosis included tumor occurrence in adults; tending to arise in distal extremities; and having bland fibromyxoid histological features, such as fibroma of tendon sheath, low-grade myxofibrosarcoma and acral myxoinflammatory fibroblastic sarcoma. It was not possible to detect the FUS/CREB3L2 and FUS/CREB3L1 fusion genes from the formalin-fixed and paraffin-embedded tissue, although the histological features of the present case were typical of LGFMS. LGFMS may become more common with time, and unique cases may accumulate.     

Molecular basis of carotid body tumor and associated clinical features in Japan identified by genomic,immunohistochemical, and clinical analyses

Carotid body tumor (CBT) is classified as a paraganglioma (PGL). Here, we report the genetic background, protein expression pattern, and clinical findings of 30 Japanese CBT cases. Germline pathogenic or likely pathogenic (P/LP) variants of genes encoding succinate dehydrogenase subunits (SDHs) were detected in 15 of 30 cases (50%). The SDHB variants were the most frequently detected, followed by SDHA and SDHD variants. One case with SDHAF2 variant was bilateral CBT, and other two multiple PGL cases were not detected P/LP variants. The three cases with germline variants that could be tested did not have somatic P/LP variants of the same genes. Immunohistochemical analysis showed negative SDHB signals in CBT tissues in five cases with germline P/LP variants of SDHB, SDHD, or SDHA. In addition, SDHB signals in CBT tissues were negative in four of nine cases without germline P/LP variants of SDHs. These findings suggest the involvement of unidentified molecular mechanisms affecting SDHs.     

Vanadyl‐TrBR4‐Catalyzed Oxidative Polymerization of Diphenyl Disulfide

A newly established catalyst system for oxygen‐oxidative polymerization of diphenyl disulfide is reported. Combination of vanadyl compounds (e.g., VO(acac)₂) and triphenylmethylium tetrakis(pentafluorophenyl)borate (TrB(C₆F₅)₄) proceeds the polymerization to give poly(1,4‐phenylene sulfide) (PPS) at 100 °C. When triphenylmethylium tetrafluoroborate (TrBF₄) is applied with vanadyl tetraphenylporphyrin (VO(TPP)) or N,N′‐(ethylenebis(salicylideneaminato))oxovanadium (VO(salen)), PPS is also given via polymerization under conditions near 160 °C. Combination of the vanadyl complex and the borate affords the first protic‐acid‐free catalytic system for the polymerization of the disulfide, suggesting the overall reaction to produce PPS and H₂O from O₂ and protons that are eliminated from the monomer.