Elevated concentrations of Se have been detected in cold, flowing water habitats near uranium and coal mines in Canada. Fish from these systems have concentrations of Se in their tissues that exceed toxic effect thresholds that have been established for warm-water fishes. However, the applicability of toxic effect thresholds and guidelines to cold water, lotic habitats is a matter of contention in the literature since most cases of Se toxicosis have been documented in standing, warm-water systems. To examine the possibility of impaired reproduction in wild rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinusfontinalis) near coal mining activity in the northeastern slopes region of Alberta, Canada, spawn from both species were collected from exposure and reference sites. Gametes were fertilized in the laboratory, reared to the swim-up stage, and examined for deformities. A significant relationship was observed for rainbow trout between the amount of Se in eggs and the incidence of developmental abnormalities, specifically craniofacial defects, skeletal deformities, and edema. These associations approximate exponential functions with probabilities that 15% of the population would be affected occurring between 8.8 and 10.5 microg Se per gram of wet egg weight, based on probit analysis. These relationships are similar to those described for centrarchids inhabiting a seleniferous warm-water lake. No such relationships were established for brook trout.

SUMMARY: Early development in fish is dependent on essential nutrients present in the egg. Vitamins E and A are critical to the normal development of fish embryos. Vitamin E functions primarily as an antioxidant to protect unsaturated lipids from oxidative degradation. Vitamin A or its provitamin carotenoid forms support growth, are required for the differentiation and maintenance of epithelial tissue and can be converted to forms of the vitamin that are potent morphogens. Fish cannot synthesise either of the vitamins, so the maternal dietary content of each prior to oogenesis is an important determinant of reproductive fitness. Here we review the basic metabolism of vitamins E and A and carotenoids and their processing from the maternal diet and deposition into eggs. Evidence for the link between levels of each of the vitamins in eggs and measures of reproductive fitness are also discussed. -El desarrollo embrionario en peces es dependiente de los nutrientes esenciales presentes en el huevo. Las vitaminas E y A son críticas en el desarrollo normal de los embriones de los peces. La vitamina E funciona sobre todo como un antioxidante para proteger los lípidos no saturados contra la degradación oxidativa. La vitamina A, o los carotenoides formas de provitamina, se requieren para la diferenciación y el mantenimiento del tejido fino epitelial y se puede convertir a las formas de la vitamina que son morfogenes potentes. Los peces tampoco pueden sintetizar las vitaminas, de modo que el contenido dietético materno de cada una antes de la oogenesis es un determinante importante de la aptitud reproductiva. Aquí repasamos el metabolismo básico de las vitaminas E y A y los carotenoides y su procesamiento desde la dieta materna a la deposición en los huevos. Se discute también la evidencia del acoplamiento entre los niveles de cada una de las vitaminas en los huevos y las medidas de aptitud reproductiva en los adultos.

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Optimal sample handling techniques for tissue preparation and storage, RNA extraction and quantification, and target gene detection are crucial for reliable gene expression analysis. Methods for measuring low-expressing genes, such as interferons, in human cervical samples are not described in the scientific literature. To detect interferon mRNA in human cervical samples we obtained normal and dysplastic frozen and formalin-fixed cervical biopsies from colposcopy. Histopathological diagnosis was performed by one pathologist. Cervical keratinocytes were isolated using laser capture microdissection. Immortalized keratinocytes transduced with or devoid of an HPV oncogene were used for initial method development. RNA from samples was extracted and integrity tested to compare tissue storage and extraction methods. The expression of five housekeeping genes was analyzed in cell lines and patient tissue to permit normalization between samples using quantitative real-time polymerase chain reaction. The usefulness of cDNA amplification was assessed for the detection of low-expressing interferon κ in cervical tissue. Here we report optimal tissue storage conditions, RNA extraction, sample normalization, and transcript amplification, as well as the sensitivity of quantitative real-time polymerase chain reaction and laser capture microdissection, for interferon κ detection in cervical tissue. Without these optimized techniques, interferon κ detection would be unattainable in cervical samples. KeywordsCervical keratinocytes; Frozen and formalin-fixed cervical tissue; Housekeeping genes; Interferons; Interferon κ; Laser capture microdissection; Quantitative real-time polymerase chain reaction Quantitative real-time polymerase chain reaction (qRT-PCR) 1 for the molecular analysis of disease is a powerful and widely used tool. Extraction of high-quality RNA for use in gene expression analysis techniques such as reverse transcription (RT), qRT-PCR, and cDNA microarrays is of great importance. Although obtaining high-quality RNA from cell lines is relatively straightforward, the complexity and heterogeneity of human tissue pose considerable challenges for linking gene expression patterns with disease state. Nonetheless,

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