Life history shapes gene expression in salmonids.
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Animal Migration↗
Biomedical subjects
Richard Powell
Publications and source records attributed to Richard Powell.
A linkage map for brown trout (Salmo trutta): chromosome homeologies and comparative genome organization with other salmonid fish.
We report on the construction of a linkage map for brown trout (Salmo trutta) and its comparison with those of other tetraploid-derivative fish in the family Salmonidae, including Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), and Arctic char (Salvelinus alpinus). Overall, we identified 37 linkage groups (2n = 80) from the analysis of 288 microsatellite polymorphisms, 13 allozyme markers, and phenotypic sex in four backcross families. Additionally, we used gene-centromere analysis to approximate the position of the centromere for 20 linkage groups and thus relate linkage arrangements to the physical morphology of chromosomes. Sex-specific maps derived from multiple parents were estimated to cover 346.4 and 912.5 cM of the male and female genomes, respectively. As previously observed in other salmonids, recombination rates showed large sex differences (average female-to-male ratio was 6.4), with male crossovers generally localized toward the distal end of linkage groups. Putative homeologous regions inherited from the salmonid tetraploid ancestor were identified for 10 pairs of linkage groups, including five chromosomes showing evidence of residual tetrasomy (pseudolinkage). Map alignments with orthologous regions in Atlantic salmon, rainbow trout, and Arctic char also revealed extensive conservation of syntenic blocks across species, which was generally consistent with chromosome divergence through Robertsonian translocations.
Animals↗
Analysis of gene expression in non-regressed and regressed bovine corpus luteum tissue using a customized ovarian cDNA array.
The lifespan of the bovine corpus luteum (CL) is an important factor in the control of normal ovarian cyclicity and the establishment and maintenance of pregnancy. There is increasing evidence that CL lifespan is regulated by alternative expression of genes that promote or inhibit luteolysis. To gain further insights into these events a 434 character ovarian cDNA array comprising genes attributed to key aspects of CL function including more than 100 anonymous expressed sequence tags (ESTs) was constructed and screened with alpha(33)P dATP labeled RNA isolated from non-regressed (n=6) and regressed (n=6) CL tissue. Significance analysis of microarrays (SAM) identified 15 genes that changed expression 1.7-fold or more with a false discovery rate of <5%. The differentially expressed genes encoded enzymes involved in steroid biosynthesis and oxygen radical metabolism and proteins involved in extracellular matrix remodeling, apoptosis and cell structure. Results for five of the differentially expressed genes including matrix gla protein and collagen alpha1(I) (extracellular matrix), glutathione-S-transferase alpha I (oxygen metabolism), clusterin (apoptosis) and scavenger receptor BI (steroid biosynthesis) were confirmed by Northern blot analysis and found to be significantly different (P<0.01) between non-regressed and regressed CL tissue. Collectively this study identified genes with recognized roles in CL regression, genes with potential roles in this process and genes whose function have yet to be defined in this event.
Animals↗
High-resolution immunophenotyping of subcellular compartments in tissue microarrays by enzyme metallography.
Ultrasensitive bright field in situ hybridization assays using enzyme metallography (EnzMet) have been developed and validated, but little is known regarding the applicability of EnzMet for immunophenotypic detection of protein via IHC. Superior resolution via discrete metallographic deposits offers the potential for enhancing high-resolution immunophenotyping. Using high-complexity tissue microarrays (TMAs), 88 common solid tumors were evaluated by automated EnzMet (Nanoprobes and Ventana). Targets were chosen to assess the ability of EnzMet to specifically localize encoded antigens in the nucleus (estrogen receptor), cytoplasm (cytokeratins), and cytoplasmic membrane (HER2) in TMAs. Results were compared with conventional IHC diaminobenzidine (DAB) immunostaining. There was full concordance between the EnzMet and conventional IHC results. Furthermore, the EnzMet reaction products did not appreciably diffuse, were dense and sharply defined, and provided excellent high-resolution differentiation of cellular compartments in paraffin sections for the nuclear, cytoplasmic, and cell membrane-localized antigens evaluated. The higher density of elemental silver deposited during enzyme metallography permitted evaluation of core immunophenotypes at a relatively low magnification, allowing more tissue to be screened in an efficient manner. This preliminary study shows the utility of using enzyme metallography for high-resolution immunophenotyping in TMAs.
Breast Neoplasms↗
Analytical validation and interobserver reproducibility of EnzMet GenePro: a second-generation bright-field metallography assay for concomitant detection of HER2 gene status and protein expression in invasive carcinoma of the breast.
Fluorescence in situ hybridization (FISH) has both excellent sensitivity and specificity in detecting HER2 gene amplification in invasive breast carcinoma. FISH has not been widely implemented in clinical practice because of reagent costs and the special instrumentation and expertise required to perform and integrate the assay. Immunohistochemistry (IHC) for HER2 protein is widely used, but false-positive and false-negative results are problematic. We developed a bright-field assay to visualize HER2 gene amplification and concomitant HER2 protein expression (EnzMet GenePro). This assay detects HER2 gene amplification via deposition of metallic silver by enzyme metallographytrade mark (EnzMettrade mark, Nanoprobes, Yaphank, NY) combined with HER2 protein detection by IHC using alkaline phosphatase and fast red K substrate visualization (CB11;Ventana, Tucson, AZ). The assay was performed on 94 invasive breast carcinomas, for which FISH (PathVysiontrade mark, Vysis, Downer's Grove, IL), conventional IHC (CB11), and enzyme metallography (EnzMettrade mark) results were known. The EnzMettrade mark component of the assay was scored as either HER2 gene amplified, polysomic, or nonamplified. The IHC component was scored using the conventional FDA scale of 0 to 3+. Concordance of the EnzMet component of the assay versus FISH was assessed and showed an excellent correlation (Pearson coefficient of 0.95; P < 0.001). The combination of gene and protein detection (EnzMet GenePro) displayed a specificity of 100% and an accuracy of 92.6% (95% confidence interval 85.3-97.0), facilitated recognition of gene/protein discordances, and allowed for efficient interpretation of the slide by conventional light microscopy. The interobserver kappa for each component was excellent (IHC, kappa = 0.94; and EnzMettrade mark, kappa = 0.96). EnzMet is the first bright-field ISH assay in our experience that routinely and nonambiguously detects endogenous HER2 signals, essential for a reliable clinical HER2 assay, and in combination with HER2 protein enables improved diagnosis in borderline cases.
Adenocarcinoma↗
A treatment for allergic rhinitis: a view on the role of levocetirizine.
BACKGROUND: Allergic rhinitis is a significant public health concern in many developed countries. However, despite evidence for a significant impact on patients' quality of life (QoL) including sleep disruption and reduced daytime performance, allergic rhinitis remains under-managed and hence poorly controlled. This is largely owing to lack of knowledge about, and poor adherence to, established treatment guidelines. SCOPE: The panel considered available evidence and focused on four published studies on the second-generation antihistamine, levocetirizine. Three of these studies explored the clinical impact of levocetirizine in a broad range of different clinical settings. FINDINGS: Levocetirizine demonstrated an increased benefit over other antihistamines in terms of a more durable antihistamine response: levocetirizine provided improved symptom relief at 24 hours compared to desloratadine or fexofenadine, two frequently prescribed second-generation antihistamines. Levocetirizine also maintained relief of the key symptoms of allergic rhinitis and improved patients' QoL over a treatment period of 6 months, in a real-life setting. The variable efficacy and durability of response of different antihistamines arise from differing modulatory effects on the H(1)-receptor. The speed of relief of symptoms with levocetirizine is supported by the pharmacokinetic data, which shows that steady state plasma concentrations are achieved in a shorter period of time than other second-generation histamines (additionally levocetirizine T(max) is reached in 0.9 h). CONCLUSION: These findings support both the short-term and long-term use of levocetirizine in the clinical management of allergic rhinitis. The World Health Organization (WHO) ARIA Guidelines (Allergic Rhinitis and its Impact on Asthma), recommend using a combination of a non-sedating antihistamine with a decongestant, or glucocorticosteroids for treating allergic rhinitis - with the order and combination of treatment depending on severity and duration of symptoms.
Cetirizine↗
Analysis of gene expression in the bovine corpus luteum through generation and characterisation of 960 ESTs.
To gain new insights into gene identity and gene expression in the bovine corpus luteum (CL) a directionally cloned CL cDNA library was constructed, screened with a total CL cDNA probe and clones representing abundant and rare mRNA transcripts isolated. The 5'-terminal DNA sequence of 960 cDNA clones, composed of 192 abundant and 768 rare mRNA transcripts was determined and clustered into 351 non-redundant expressed sequence tag (EST) groups. Bioinformatic analysis revealed that 309 (88%) of the ESTs showed significant homology to existing sequences in the protein and nucleotide public databases. Several previously unidentified bovine genes encoding proteins associated with key aspects of CL function including extracellular matrix remodelling, lipid metabolism/steroid biosynthesis and apoptosis, were identified. Forty-two (12%) of the ESTs showed homology with human or with other uncharacterised ESTs, some of these were abundantly expressed and may therefore play an important role in primary CL function. Tissue-specificity and temporal CL gene expression of selected clones previously unidentified in bovine CL tissue was also examined. The most interesting finds indicated that mRNA encoding squalene epoxidase was constitutively expressed in CL tissue throughout the oestrous cycle and 7-fold down-regulated (P < 0.05) in late luteal tissue, concomitant with the disappearance of systemic progesterone, suggesting that de novo cholesterol biosynthesis plays an important role in steroidogenesis. The mRNA encoding the growth factor, insulin-like growth factor-binding protein-related protein 1 (IGFBP-rP1), remained constant during the oestrous cycle and was 1.8-fold up-regulated (P < 0.05) in late luteal tissue implying a role in CL regression.
Animals↗
Novel bright field molecular morphology methods for detection of HER2 gene amplification.
Profiling the amplification and over-expression of the HER2 gene is a key component for defining the prognosis and management of invasive breast carcinoma. Clinical laboratory testing for HER2 gene amplification and over expression has been complicated by an unacceptably high rate of false positive immunohistochemistry (IHC) results, poor reproducibility for the '2+' category of IHC scoring, and reluctant acceptance of alternative testing by fluorescence in situ hybridization (FISH) by the diagnostic pathology community. Novel chromogenic in situ hybridization (CISH) assays have been developed that utilize bright field microscopy and a conventional light microscope for interpretation, but the analytical sensitivity of first generation CISH systems has been problematic. Novel second generation in situ hybridization detection methods based upon polymerized lg detection chemistry, autometallography or enzyme metallography, have been developed that routinely detect endogenous HER2 signals in normal cells (on slide hybridization control) and HER2 signals in both non-amplified and amplified patterns of HER2 genomic signatures. By combining the strength of polymerized peroxidase-labeled antibodies and metallography for gene amplification, with the detection of expression of HER2 encoded protein by IHC on the same slide, both HER2 gene amplification and protein over-expression can be simultaneously evaluated on a cell-by-cell basis in each microscopic field of carcinoma.
Breast Neoplasms↗
Mutations in the genes for oocyte-derived growth factors GDF9 and BMP15 are associated with both increased ovulation rate and sterility in Cambridge and Belclare sheep (Ovis aries).
Belclare and Cambridge are prolific sheep breeds, the origins of which involved selecting ewes with exceptionally high litter size records from commercial flocks. The variation in ovulation rate in both breeds is consistent with segregation of a gene (or genes) with a large effect on this trait. Sterile ewes, due to a failure of normal ovarian follicle development, occur in both breeds. New naturally occurring mutations in genes for the oocyte-derived growth factors growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are described. These mutations are associated with increased ovulation rate in heterozygous carriers and sterility in homozygous carriers in both breeds. This is the first time that a mutation in the gene for GDF9 has been found that causes increased ovulation rate and infertility in a manner similar to inactivating mutations in BMP15, and shows that GDF9 is essential for normal folliculogenesis in sheep. Furthermore, it is shown, for the first time in any species, that individuals with mutations in both GDF9 and BMP15 have a greater ovulation rate than sheep with either of the mutations separately.
Amino Acid Sequence↗
Comparative genome analysis of the primary sex-determining locus in salmonid fishes.
We compared the Y-chromosome linkage maps for four salmonid species (Arctic charr, Salvelinus alpinus; Atlantic salmon, Salmo salar; brown trout, Salmo trutta; and rainbow trout, Oncorhynchus mykiss) and a putative Y-linked marker from lake trout (Salvelinus namaycush). These species represent the three major genera within the subfamily Salmoninae of the Salmonidae. The data clearly demonstrate that different Y-chromosomes have evolved in each of the species. Arrangements of markers proximal to the sex-determining locus are preserved on homologous, but different, autosomal linkage groups across the four species studied in detail. This indicates that a small region of DNA has been involved in the rearrangement of the sex-determining region. Placement of the sex-determining region appears telomeric in brown trout, Atlantic salmon, and Arctic charr, whereas an intercalary location for SEX may exist in rainbow trout. Three hypotheses are proposed to account for the relocation: translocation of a small chromosome arm; transposition of the sex-determining gene; or differential activation of a primary sex-determining gene region among the species.
Animals↗
Psychometric properties of the Beck Depression Inventory and the Zung Self Rating Depression Scale in adults with mental retardation.
The psychometric properties of the Beck Depression Inventory and the Zung Self Rating Depression Scale were examined. Both tests were administered to 120 adults with mental retardation. Results were analyzed, correlated, and examined with principle component analysis. Findings suggest that the tests have good clinical utility with these persons and that depression may be more severe in people with mental retardation. Characteristics that can be employed in building other behavioral measures of depression for persons with mental retardation were also identified. Results show that there may be a tendency for persons with mental retardation to minimize distress report, further complicating the depression diagnostic process for these persons.
Adult↗
EST-based identification of genes expressed in the liver of adult Atlantic salmon (Salmo salar).
A list of genes expressed in the liver of Atlantic salmon was compiled using the expressed sequence tag (EST) strategy. 733 ESTs, derived from 170 abundant and 563 rare mRNA encoding liver cDNA clones, were determined. Bioinformatic analysis revealed that 390 (53%) of the salmon liver ESTs could be ascribed to the transcriptional products of 93 identified genes including 7 previously described in the Atlantic salmon. The identified Atlantic salmon genes were classified with respect to cellular role which showed that 33 (36%) of the identified genes encoded proteins associated with primary liver functions such as transport, acute phase response, and blood clotting. Furthermore, comparative analysis revealed that 12 of the 16 salmon genes that were shown to encode abundant mRNA transcripts in liver had homologues that have also been shown to be highly expressed in mammalian liver systems. Finally, two cDNA variants corresponding to the two cDNA forms of the apolipoprotein A-I gene previously identified in rainbow trout were also found in Atlantic salmon.
Amino Acid Sequence↗
Postmortem stability of RNA isolated from bovine reproductive tissues.
Molecular biology is being increasingly used to address the complex problem of bovine infertility. One common concern shared by many of these studies is the postmortem delay in obtaining reproductive tissues and the effect this may have on RNA dependent studies. To address this concern, bovine ovarian, oviduct and uterine tissue samples, collected over intervals ranging from 0 to 96 h postmortem to freeze storage, were analysed to determine the potential effects on RNA quantity and quality. The analysis showed that total RNA yields were not changed significantly by postmortem interval up to 96 h while 28S ribosomal RNA remained intact up to 24 h postmortem. Specific messenger RNA transcripts encoding beta-actin, GAPDH and transforming growth factor-beta were detected in all tissues up to 96 h postmortem using reverse transcriptase-polymerase chain reaction and Northern analysis indicated no detectable mRNA degradation up to 24 h postmortem. Finally, using poly(A)(+) mRNA isolated from ovarian tissues frozen 2 h postmortem, we constructed corpus luteum and ovarian cortex cDNA libraries containing 7.65x10(4) and 1.9x10(6) primary transformants with average cDNA lengths of 2.3 and 1.6 kb respectively. Taken together, these data show that a postmortem delay of up to 24 h does not significantly affect the yield or quality of RNA prepared from bovine reproductive tissues.
Actins↗
Analysis and management of resistance to chemotherapeutants in salmon lice, Lepeophtheirus salmonis (Copepoda: Caligidae).
In Northern Europe and Canada, the salmon louse, Lepeophtheirus salmonis (Krøyer), seriously affects the marine phase of salmon production. Although the problem is long-standing, the development of sustainable methods of pest management has been unable to keep pace with the intensification of production, leading to large-scale reliance on very few chemotherapeutants. This runs the risk of selecting for genetically determined resistance in target organisms. There are many examples of similar evolutionary adaptations in arthropod pests of arable crops, livestock and human health. Several hundred pest species are now documented as being resistant to one or more chemical classes of insecticides and acaricides. Many of these compounds are identical or closely related to ones currently employed against salmon lice. It is, therefore, opportune to consider what lessons have been learnt from contending with resistance in terrestrial organisms, the implications for sustainable use of chemotherapeutants in aquaculture, and the potential for developing effective resistance management strategies. An EU-funded project named SEARCH (QLK2-CT-2000-00809) has been initiated to explore in more detail the diagnosis, incidence, dynamics and management of resistance to chemotherapeutants in L salmonis.
Animals↗
Gold-facilitated in situ hybridization: a bright-field autometallographic alternative to fluorescence in situ hybridization for detection of Her-2/neu gene amplification.
Fluorescence in situ hybridization (FISH) represents an excellent method for profiling gene amplification in situ, but correlation with tissue morphology is difficult because of dark-field visualization. Validation of a bright-field assay for assessment of HER-2/neu gene amplification was investigated. Streptavidin-Nanogold was used to generate bright-field gene copy signals using GoldEnhance gold-based autometallography, catalyzed reported deposition, and a biotin-labeled probe. One hundred cases of invasive breast carcinoma were evaluated for which FISH gene copy results, and mRNA and oncoprotein gene expression, were known. Autometallographic signals were qualitatively evaluable without the use of oil immersion microscopy. Results correlated well with indirect and direct label FISH. Autometallographic gold-based in situ hybridization represents a promising bright-field assay for the assessment of HER-2/neu gene amplification.
Breast Neoplasms↗
Interobserver interpretative reproducibility of GOLDFISH, a first generation gold-facilitated autometallographic bright field in situ hybridization assay for HER-2/neu amplification in invasive mammary carcinoma.
Clinical laboratory testing for HER-2/neu gene amplification by fluorescence in situ hybridization is not widely used in diagnostic pathology laboratories. A bright field alternative permitting direct visualization of gene amplification using conventional microscopy may be more readily incorporated into routine diagnostic pathology practice. Interobserver reproducibility represents an important component of the validation of such an assay. We tested the hypothesis that a first-generation bright field alternative to fluorescence in situ hybridization, a Nanogold (Nanoprobes, Inc, Yaphank, NY, USA) (or gold-label)/autometallographic assay for HER-2/neu gene amplification in breast carcinoma, can be reproducibly interpreted by pathologists. Reference standard was direct fluorescence in situ hybridization supplemented by RNA/RNA in situ hybridization. Reproducibility of selected conventional histologic parameters was captured based on a hematoxylin and eosin slide accompanying the GOLDFISH preparation (gold-facilitated autometallographic in situ hybridization) as an indication of comparative reproducibility. The average kappa among GOLDFISH observers was 0.84, which was at least or concordant of observers scoring nuclear grade (kappa = 0.50) and the presence of in situ carcinoma (kappa = 0.57) by conventional histopathology. The GOLDFISH assay was specifically designed for qualitative interpretation, thus obviating the need for oil immersion microscopy and signal enumeration, and its interpretation was highly reproducible among five pathologists.
Breast Neoplasms↗