805 research outputs found
Critical Media Studies: An Introduction
Critical media studies is a state of the arta introduction to media studies that demonstrate how to think critically about the power and influence of the media. Written in an accesible and enganging style, each of the book’s elevan critical perspective according to their focus on media industries, messages and audiences. Rather than treating any single approach to media as the correct one, critical media studies illustrate that different perspective yield different insights and encourages critics to develop facility with multiple perspective. The book combines the best of well tested theory with cutting edge scholarship on the media
Marsupials and rodents of the Admiralty Islands, Papua New Guinea
We provide the first account of all non-volant, non-marine mammals recorded, whether reliably, questionably, or erroneously, from the Admiralty Islands, Papua New Guinea. Species recorded with certainty, or near certainty, are the bandicoot Echymipera cf. kalubu, the widespread cuscus Phalanger orientalis, the endemic (?) cuscus Spilocuscus kraemeri, the endemic rat Melomys matambuai, a recently described species of endemic Rattus, R. detentus, and the commensal rodents Rattus exulans and Rattus rattus. Species erroneously reported from the islands or whose presence has yet to be confirmed are the rats Melomys bougainville, Rattus mordax, Rattus praetor, and Uromys neobrittanicus. Included additional specimens to those previously reported in the literature are of Spilocuscus kraemeri and two new specimens of the endemic Melomys matambuai, previously known only from the holotype and a paratype, and new specimens of Rattus exulans. The identity of a specimen previously thought to be of Spilocuscus kraemeri and said to have been taken on Bali, an island off the coast of West New Britain, does appear to be of that species, although this animal is generally thought of as occurring only in the Admiralties and vicinity. Summaries from the literature and new information are provided on the morphology, variation, natural history, and zoogeography of the species treated
CDKN1C/p57kip2 Is a Candidate Tumor Suppressor Gene in Human Breast Cancer
BACKGROUND. CDKN1C (also known as p57KIP2) is a cyclin-dependent kinase inhibitor previously implicated in several types of human cancer. Its family members (CDKN1A/p21CIP1 and B/p27KIP1) have been implicated in breast cancer, but information about CDKN1C's role is limited. We hypothesized that decreased CDKN1C may be involved in human breast carcinogenesis in vivo. METHODS. We determined rates of allele imbalance or loss of heterozygosity (AI/LOH) in CDKN1C, using an intronic polymorphism, and in the surrounding 11p15.5 region in 82 breast cancers. We examined the CDKN1C mRNA level in 10 cancers using quantitative real-time PCR (qPCR), and the CDKN1C protein level in 20 cancers using immunohistochemistry (IHC). All samples were obtained using laser microdissection. Data were analyzed using standard statistical tests. RESULTS. AI/LOH at 11p15.5 occurred in 28/73 (38%) informative cancers, but CDKN1C itself underwent AI/LOH in only 3/16 (19%) cancers (p = ns). In contrast, CDKN1C mRNA levels were reduced in 9/10 (90%) cancers (p < 0.0001), ranging from 2–60% of paired normal epithelium. Similarly, CDKN1C protein staining was seen in 19/20 (95%) cases' normal epithelium but in only 7/14 (50%) cases' CIS (p < 0.004) and 5/18 (28%) cases' IC (p < 0.00003). The reduction appears primarily due to loss of CDKN1C expression from myoepithelial layer cells, which stained intensely in 17/20 (85%) normal lobules, but in 0/14 (0%) CIS (p < 0.00001). In contrast, luminal cells displayed less intense, focal staining fairly consistently across histologies. Decreased CDKN1C was not clearly associated with tumor grade, histology, ER, PR or HER2 status. CONCLUSION. CDKN1C is expressed in normal epithelium of most breast cancer cases, mainly in the myothepithelial layer. This expression decreases, at both the mRNA and protein level, in the large majority of breast cancers, and does not appear to be mediated by AI/LOH at the gene. Thus, CDKN1C may be a breast cancer tumor suppressor.Department of Defense Breast Cancer Research Program (DAMD 17-99-1-9573); National Institutes of Health PHS (CA081078); LaPann Fun
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Validation of a Predictive Model for Survival in Patients With Advanced Cancer: Secondary Analysis of RTOG 9714.
BackgroundThe objective of this study was to validate a simple predictive model for survival of patients with advanced cancer.MethodsPrevious studies with training and validation datasets developed a model predicting survival of patients referred for palliative radiotherapy using three readily available factors: primary cancer site, site of metastases and Karnofsky performance score (KPS). This predictive model was used in the current study, where each factor was assigned a value proportional to its prognostic weight and the sum of the weighted scores for each patient was survival prediction score (SPS). Patients were also classified according to their number of risk factors (NRF). Three risk groups were established. The Radiation Therapy and Oncology Group (RTOG) 9714 data was used to provide an additional external validation set comprised of patients treated among multiple institutions with appropriate statistical tests.ResultsThe RTOG external validation set comprised of 908 patients treated at 66 different radiation facilities from 1998 to 2002. The SPS method classified all patients into the low-risk group. Based on the NRF, two distinct risk groups with significantly different survival estimates were identified. The ability to predict survival was similar to that of the training and previous validation datasets for both the SPS and NRF methods.ConclusionsThe three variable NRF model is preferred because of its relative simplicity
Floral homeotic C function genes repress specific B function genes in the carpel whorl of the basal eudicot California poppy (Eschscholzia californica)
<p>Abstract</p> <p>Background</p> <p>The floral homeotic C function gene <it>AGAMOUS </it>(<it>AG</it>) confers stamen and carpel identity and is involved in the regulation of floral meristem termination in <it>Arabidopsis</it>. <it>Arabidopsis ag </it>mutants show complete homeotic conversions of stamens into petals and carpels into sepals as well as indeterminacy of the floral meristem. Gene function analysis in model core eudicots and the monocots rice and maize suggest a conserved function for <it>AG </it>homologs in angiosperms. At the same time gene phylogenies reveal a complex history of gene duplications and repeated subfunctionalization of paralogs.</p> <p>Results</p> <p><it>EScaAG1 </it>and <it>EScaAG2</it>, duplicate <it>AG </it>homologs in the basal eudicot <it>Eschscholzia californica </it>show a high degree of similarity in sequence and expression, although <it>EScaAG2 </it>expression is lower than <it>EScaAG1 </it>expression. Functional studies employing virus-induced gene silencing (VIGS) demonstrate that knock down of <it>EScaAG1 </it>and <it>2 </it>function leads to homeotic conversion of stamens into petaloid structures and defects in floral meristem termination. However, carpels are transformed into petaloid organs rather than sepaloid structures. We also show that a reduction of <it>EScaAG1 </it>and <it>EScaAG2 </it>expression leads to significantly increased expression of a subset of floral homeotic B genes.</p> <p>Conclusions</p> <p>This work presents expression and functional analysis of the two basal eudicot <it>AG </it>homologs. The reduction of <it>EScaAG1 </it>and <it>2 </it>functions results in the change of stamen to petal identity and a transformation of the central whorl organ identity from carpel into petal identity. Petal identity requires the presence of the floral homeotic B function and our results show that the expression of a subset of B function genes extends into the central whorl when the C function is reduced. We propose a model for the evolution of B function regulation by C function suggesting that the mode of B function gene regulation found in <it>Eschscholzia </it>is ancestral and the C-independent regulation as found in <it>Arabidopsis </it>is evolutionarily derived.</p
Floral homeotic C function genes repress specific B function genes in the carpel whorl of the basal eudicot California poppy (Eschscholzia californica)
<p>Abstract</p> <p>Background</p> <p>The floral homeotic C function gene <it>AGAMOUS </it>(<it>AG</it>) confers stamen and carpel identity and is involved in the regulation of floral meristem termination in <it>Arabidopsis</it>. <it>Arabidopsis ag </it>mutants show complete homeotic conversions of stamens into petals and carpels into sepals as well as indeterminacy of the floral meristem. Gene function analysis in model core eudicots and the monocots rice and maize suggest a conserved function for <it>AG </it>homologs in angiosperms. At the same time gene phylogenies reveal a complex history of gene duplications and repeated subfunctionalization of paralogs.</p> <p>Results</p> <p><it>EScaAG1 </it>and <it>EScaAG2</it>, duplicate <it>AG </it>homologs in the basal eudicot <it>Eschscholzia californica </it>show a high degree of similarity in sequence and expression, although <it>EScaAG2 </it>expression is lower than <it>EScaAG1 </it>expression. Functional studies employing virus-induced gene silencing (VIGS) demonstrate that knock down of <it>EScaAG1 </it>and <it>2 </it>function leads to homeotic conversion of stamens into petaloid structures and defects in floral meristem termination. However, carpels are transformed into petaloid organs rather than sepaloid structures. We also show that a reduction of <it>EScaAG1 </it>and <it>EScaAG2 </it>expression leads to significantly increased expression of a subset of floral homeotic B genes.</p> <p>Conclusions</p> <p>This work presents expression and functional analysis of the two basal eudicot <it>AG </it>homologs. The reduction of <it>EScaAG1 </it>and <it>2 </it>functions results in the change of stamen to petal identity and a transformation of the central whorl organ identity from carpel into petal identity. Petal identity requires the presence of the floral homeotic B function and our results show that the expression of a subset of B function genes extends into the central whorl when the C function is reduced. We propose a model for the evolution of B function regulation by C function suggesting that the mode of B function gene regulation found in <it>Eschscholzia </it>is ancestral and the C-independent regulation as found in <it>Arabidopsis </it>is evolutionarily derived.</p
Inflammatory monocytes require type I interferon receptor signaling to activate NK cells via IL-18 during a mucosal viral infection
The requirement of type I interferon (IFN) for natural killer (NK) cell activation in response to viral infection is known, but the underlying mechanism remains unclear. Here, we demonstrate that type I IFN signaling in inflammatory monocytes, but not in dendritic cells (DCs) or NK cells, is essential for NK cell function in response to a mucosal herpes simplex virus type 2 (HSV-2) infection. Mice deficient in type I IFN signaling, Ifnar(-/-) and Irf9(-/-) mice, had significantly lower levels of inflammatory monocytes, were deficient in IL-18 production, and lacked NK cell-derived IFN-gamma. Depletion of inflammatory monocytes, but not DCs or other myeloid cells, resulted in lower levels of IL-18 and a complete abrogation of NK cell function in HSV-2 infection. Moreover, this resulted in higher susceptibility to HSV-2 infection. Although Il18(-/-) mice had normal levels of inflammatory monocytes, their NK cells were unresponsive to HSV-2 challenge. This study highlights the importance of type I IFN signaling in inflammatory monocytes and the induction of the early innate antiviral response
Embryonic Stem Cells Are Redirected to Non-Tumorigenic Epithelial Cell Fate by Interaction with the Mammary Microenvironment
Experiments were conducted to redirect mouse Embryonic Stem (ES) cells from a tumorigenic phenotype to a normal mammary epithelial phenotype in vivo. Mixing LacZ-labeled ES cells with normal mouse mammary epithelial cells at ratios of 1:5 and 1:50 in phosphate buffered saline and immediately inoculating them into epithelium-divested mammary fat pads of immune-compromised mice accomplished this. Our results indicate that tumorigenesis occurs only when normal mammary ductal growth is not achieved in the inoculated fat pads. When normal mammary gland growth occurs, we find ES cells (LacZ+) progeny interspersed with normal mammary cell progeny in the mammary epithelial structures. We demonstrate that these progeny, marked by LacZ expression, differentiate into multiple epithelial subtypes including steroid receptor positive luminal cells and myoepithelial cells indicating that the ES cells are capable of epithelial multipotency in this context but do not form teratomas. In addition, in secondary transplants, ES cell progeny proliferate, contribute apparently normal mammary progeny, maintain their multipotency and do not produce teratomas
Complete plastid genome sequences of Drimys, Liriodendron, and Piper: implications for the phylogenetic relationships of magnoliids
BACKGROUND: The magnoliids with four orders, 19 families, and 8,500 species represent one of the largest clades of early diverging angiosperms. Although several recent angiosperm phylogenetic analyses supported the monophyly of magnoliids and suggested relationships among the orders, the limited number of genes examined resulted in only weak support, and these issues remain controversial. Furthermore, considerable incongruence resulted in phylogenetic reconstructions supporting three different sets of relationships among magnoliids and the two large angiosperm clades, monocots and eudicots. We sequenced the plastid genomes of three magnoliids, Drimys (Canellales), Liriodendron (Magnoliales), and Piper (Piperales), and used these data in combination with 32 other angiosperm plastid genomes to assess phylogenetic relationships among magnoliids and to examine patterns of variation of GC content. RESULTS: The Drimys, Liriodendron, and Piper plastid genomes are very similar in size at 160,604, 159,886 bp, and 160,624 bp, respectively. Gene content and order are nearly identical to many other unrearranged angiosperm plastid genomes, including Calycanthus, the other published magnoliid genome. Overall GC content ranges from 34–39%, and coding regions have a substantially higher GC content than non-coding regions. Among protein-coding genes, GC content varies by codon position with 1st codon > 2nd codon > 3rd codon, and it varies by functional group with photosynthetic genes having the highest percentage and NADH genes the lowest. Phylogenetic analyses using parsimony and likelihood methods and sequences of 61 protein-coding genes provided strong support for the monophyly of magnoliids and two strongly supported groups were identified, the Canellales/Piperales and the Laurales/Magnoliales. Strong support is reported for monocots and eudicots as sister clades with magnoliids diverging before the monocot-eudicot split. The trees also provided moderate or strong support for the position of Amborella as sister to a clade including all other angiosperms. CONCLUSION: Evolutionary comparisons of three new magnoliid plastid genome sequences, combined with other published angiosperm genomes, confirm that GC content is unevenly distributed across the genome by location, codon position, and functional group. Furthermore, phylogenetic analyses provide the strongest support so far for the hypothesis that the magnoliids are sister to a large clade that includes both monocots and eudicots
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