DNA strand breaks and adducts determined in feral and caged chub (Leuciscus cephalus) exposed to rivers exhibiting variable water quality around Birmingham, UK.

This study forms part of an investigation into the effects on fish of immersion in three rivers around Birmingham, UK. The rivers Blythe, Cole and Tame exhibit relatively high, intermediate and poor overall water quality, respectively, according to combined levels of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), as well as heavy metals. Specifically, biomarkers of genotoxicity (DNA strand breaks and adducts) were measured in feral and caged chub (Leuciscus cephalus), complementing another study in which data were presented for a number of other hepatic biomarkers measured in the same animals. In both feral and caged chub, there was a general elevation of DNA strand breaks with a decrease in chemical water quality, with some time points exhibiting significantly higher levels at the most (Tame) compared with least polluted sites (Blythe), particularly in the cage-held animals. Combined-season DNA adduct data suggested a higher degree of toxic insult in the feral compared with caged chub and revealed particularly high levels of adducts in fish caught from the Cole. The pattern of adducts shown was typical of exposure to a complex mixture of PAHs which were relatively high, and similar, in both the Cole and Tame. Overall, these data are consistent with exposure of both feral and caged chub to contaminants which are able to induce specific, moderately genotoxic effects.

Cloning of a chub metallothionein cDNA and development of competitive RT-PCR of chub metallothionein mRNA as a potential biomarker of heavy metal exposure.

Metallothionein has been assayed in a range of aquatic animal tissues as an indicator of metal exposure. We sequenced chub (Leuciscus cephalus) metallothionein cDNA which showed over 90% homology to common carp, goldfish and stone loach and 77% homology to rainbow trout sequences for metallothionein. We then used the extended primer method to develop an accurate quantitative competitive RT-PCR assay for metallothionein mRNA. RT-PCR was used to measure metallothionein mRNA in feral chub from a range of field sites, with different levels of heavy metal pollution, in the West Midlands, UK. Measurements were complemented by analysis of liver and gill metallothionein protein by capillary electrophoresis. There was no significant difference in the metallothionein protein levels between fish of different rivers and there was no evidence of elevation of mRNA at the sites of highest metal exposure. The level of metal exposure (e.g. zinc, nickel and cadmium each ranging between 15 and 28 microg/l ) at the pH (7.5-8.5) of these rivers appears insufficient to elevate hepatic or gill metallothionein in chub. A lack of elevation of hepatic metallothionein mRNA in chub exposed to zinc, copper and manganese for 24 h and 10 days in the laboratory also suggests a non-responsiveness of this species.

HMB-45 (gp103) and MART-1 expression within giant cells in an atypical fibroxanthoma: a case report.

BACKGROUND: Atypical fibroxanthoma (AFX) is a cutaneous tumor that primarily occurs in the sun-damaged skin of the head and neck of adults. It is often a rapidly growing, solitary lesion that may clinically resemble squamous cell carcinoma, malignant melanoma, or lobular hemangioma. The histologic differential diagnosis primarily includes spindle cell squamous carcinoma and spindle cell melanoma, and immunohistochemical studies are often needed to establish the diagnosis. CASE REPORT: We report an unusual case of an AFX with aberrant HMB-45 and MART-1 (melanoma antigen recognized by T cells-1) immunohistochemical expression. Clinical information was obtained. Histologic examination and immunohistochemical studies were performed. RESULTS: A 54-year-old woman presented with a 1.5 cm posterior scalp lesion, which was excised. Microscopic examination revealed a dermal tumor composed of pleomorphic and spindled cells with numerous giant cells. The tumor cells expressed CD68 but did not express either keratin or S-100. In addition, there was focal gp100 (with HMB-45) and MART-1 expression limited to the large, multinucleated cells with vacuolated cytoplasm. A diagnosis of AFX was subsequently made. CONCLUSIONS: This is the first reported case of an AFX with HMB-45 and MART-1 reactivity.