Atrophic hepatocytes express keratin 7 in ischemia-associated liver lesions.

AIM: To investigate atrophic parenchymal changes in ischemic liver conditions. DESIGN: We studied 18 cases of hepatic lesions with atrophic changes due to altered blood flow (hepatic venous congestion n=15 including 4 cases with additional nodular regenerative hyperplasia-NRH, NRH n=1, and antiphospholipid syndrome with patchy parenchymal atrophy n=2). Metaplastic hepatocellular changes, hepatocyte proliferation, hepatic stellate cell (HSC) activation, and sinusoidal capillarization were examined immunohistochemically with antibodies to keratins (K) 7 and 19, Ki67, αSMA and CD34, respectively. RESULTS: K7 was positive and K19 was negative in zone 3 atrophic hepatocytes in venous congestion and in areas of plate atrophy, as well as in congested or compressed sites in NRH. Sinusoidal CD34-positivity indicating capillarization accompanied K7 immunoexpression. Masson trichrome revealed sinusoidal fibrosis to be restricted in atrophic areas, usually mild and in 7 cases focally dense. αSMA expression expanded beyond K7-positive areas. Ki67 was negative in K7-positive hepatocytes. CONCLUSION: Ischemic parenchymal changes are characterized by hepatocyte K7 immunoexpression, sinusoidal capillarization, HSC activation and lack of cellular proliferation, indicating an early reaction of the major liver parenchyma cellular components creating a more resistant microenvironment. These phenotypic alterations may prove valuable in the discrimination of ischemic liver lesions.

Ectopic hepatocellular carcinomas developed in the chest wall and skull.

A 68-year-old man presented with a suppurating mass on his skull and a palpable mass on his right upper thoracic wall. Computed tomography revealed a round mass, 70 mm in diameter, invading the right pleural cavity, and a second tumor infiltrating the skull through the left parietal bone. Both masses were resected simultaneously. Histopathology showed that both tumors were hepatocellular carcinomas.

H-ras and c-fos exhibit similar expression patterns during most stages of oral oncogenesis.

BACKGROUND: H-ras and c-fos oncogenes interact in signalling pathways but their level and time course of expression during oral cancer development are unclear. The present study used an animal model for the simultaneous investigation of H-Ras and c-Fos expression in sequential stages of oral oncogenesis. MATERIALS AND METHODS: Three experimental groups of Syrian golden hamsters (A, B and C; 10 animals each) and one control group (7 animals) were used. The buccal pouches of hamsters in groups A, B and C were treated with 0.5% of the carcinogen 9,10-dimethyl-1,2-benzanthracene and were excised at 10, 14 and 19 weeks, respectively. The biopsies, which included tissue stages ranging from normal oral mucosa to moderately differentiated carcinoma, were studied immunohistochemically. RESULTS: A reduction in both H-Ras and c-Fos expression was observed from group A to B and from hyperplasias to early tumour stages, while a simultaneous increase was noted from group B to C and from well-differentiated to moderately-differentiated carcinomas. The H-ras/c-fos expression ratio had a value of approximately (1.09 +/- 0.21) in five out of seven studied tissue stages. CONCLUSION: H-Ras and c-Fos exhibit a similar expression pattern throughout most stages of oral carcinogenesis, an observation supported by the known molecular pathway connecting H-ras signalling with subsequent c-fos gene transcription.

Tissue-specific mtDNA lesions and radical-associated mitochondrial dysfunction in human hearts exposed to doxorubicin.

Doxorubicin causes a chronic cardiomyopathy. Although the exact pathogenesis is unknown, recent animal data suggest that somatically acquired alterations of mitochondrial DNA (mtDNA) and concomitant mitochondrial dysfunction play an important role in its onset. In this study, skeletal and myocardial muscles were examined from human autopsies. Compared to controls (n = 8), doxorubicin-exposed hearts (n = 6) showed low absolute enzyme activity of mtDNA-encoded nicotinamide adenine dinucleotide hydrogen dehydrogenase (NADH DH, 79% residual activity, p = 0.03) and cytochrome c oxidase (COX, 59% residual activity, p < 0.001), but not of succinate dehydrogenase (SDH), which is encoded exclusively by nuclear DNA. NADH DH/SDH and COX/SDH ratios were 37% (p < 0.001) and 27% (p < 0.001) of controls. Expression of the mtDNA-encoded subunit II of COX was reduced (82%, p = 0.04), compared to its unchanged nucleus-encoded subunit IV. MtDNA-content was diminished (56%, p = 0.02), but the 'common' mtDNA-deletion was increased (9.2-fold, p = 0.004). Doxorubicin-exposed hearts harboured numerous additional mtDNA rearrangements lacking direct repeats. They contained elevated levels of malondialdehyde (MDA) (p = 0.006, compared to controls), which correlated inversely with the COX/SDH ratio (r = -0.45, p = 0.02) and the mtDNA-content (r = -0.75, p = 0.002), and correlated positively with the levels of the 'common' deletion (r = 0.80, p < 0.001). Doxorubicin-exposed hearts also contained the highest levels of superoxide (p < 0.001, compared to controls), which correlated negatively with the mtDNA-encoded respiratory chain activities, such as the COX/SDH ratio (r = -0.57, p = 0.02) and the NADH/SDH ratio (r = -0.52, p = 0.04), as well as with the mtDNA content (r = -0.69, p = 0.003), and correlated positively with the frequency of the 'common' deletion (r = 0.76, p < 0.001) and the MDA levels (r = 0.86, p < 0.001). Doxorubicin-exposed hearts contained electron-dense deposits within mitochondria. Hearts exposed to other anthracyclines (n = 6) or skeletal muscle (all groups) had no mitochondrial dysfunction. Doxorubicin, unlike other anthracyclines, augments lipid peroxidation, induces mtDNA mutations and decreases mtDNA content in human hearts. These lesions have an impact on mitochondrial function and could be of importance in the pathogenesis of clinical cardiomyopathy.