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Unique Biology (unique + biology)
Selected AbstractsA role for glutamate in growth and invasion of primary brain tumorsJOURNAL OF NEUROCHEMISTRY, Issue 2 2008Harald Sontheimer Abstract The vast majority of primary brain tumors derive from glial cells and are collectively called gliomas. While, they share some genetic mutations with other cancers, they do present with a unique biology and have developed adaptations to meet specific biological needs. Notably, glioma growth is physically restricted by the skull, and, unless normal brain cells are destroyed, tumors cannot expand. To overcome this challenge, glioma cells release glutamate which causes excitotoxic death to surrounding neurons, thereby vacating room for tumor expansion. The released glutamate also explains peritumoral seizures which are a common symptom early in the disease. Glutamate release occurs via system Xc, a cystine,glutamate exchanger that releases glutamate in exchange for cystine being imported for the synthesis of the cellular antioxidant GSH. It protects tumor cells from endogenously produced reactive oxygen and nitrogen species but also endows tumors with an enhanced resistance to radiation- and chemotherapy. Pre-clinical data demonstrates that pharmacological inhibition of system Xc causes GSH depletion which slows tumor growth and curtails tumor invasion in vivo. An Food and Drug Administration approved drug candidate is currently being introduced into clinical trials for the treatment of malignant glioma. [source] Characterization and isolation of DNA microsatellite primers in the spiny dogfish (Squalus acanthias)MOLECULAR ECOLOGY RESOURCES, Issue 3 2004LINDA McCAULEY Abstract The North Atlantic spiny dogfish (Squalus acanthias) population has been declining since the 1980s. Proper management of this population is essential as dogfish are prone to rapid collapse based on the unique biology of this species. We characterized eight microsatellite loci for spiny dogfish to use in determining the genetic structure of this species along the Atlantic coast of the USA. [source] Manganese-enhanced magnetic resonance imaging (MEMRI)NMR IN BIOMEDICINE, Issue 8 2004Alan P. Koretsky Abstract Manganese ion (Mn2+) is an essential metal that participates as a cofactor in a number of critical biological functions, such as electron transport, detoxification of free radicals and synthesis of neurotransmitters. Mn2+ can enter excitable cells using some of the same transport systems as Ca2+ and it can bind to a number of intracellular sites because it has high affinity for Ca2+ and Mg2+ binding sites on proteins and nucleic acids. Paramagnetic forms of manganese ions are potent MRI relaxation agents. Indeed, Mn2+ was the first contrast agent proposed for use in MRI. Recently, there has been renewed interest in combining the strong MRI relaxation effects of Mn2+ with its unique biology, in order to further expand the already broad assortment of useful information that can be measured by MRI. Such an approach has been continuously developed in the past several years to provide unique tissue contrast, to assess tissue viability, to act as a surrogate marker of calcium influx into cells and to trace neuronal connections. This special issue of NMR in Biomedicine on manganese-enhanced MRI (MEMRI) is aimed at providing the readers of this journal with an extensive review of some of the most prominent applications of MEMRI in biological systems. Written by several of the leaders in the field, the reviews and original research articles featured in this special issue are likely to offer an exciting and inspiring view of the broad range of applications of MEMRI. Copyright © 2004 John Wiley & Sons, Ltd. [source] Human papillomavirus and WHO type I nasopharyngeal carcinoma,,THE LARYNGOSCOPE, Issue 10 2010Emily J. Lo BA Abstract Objectives: Nasopharyngeal carcinoma (NPC) is a rare cancer in the United States. An association between NPC and Epstein-Barr virus (EBV) is well-established for World Health Organization (WHO) types II and III (WHO-II/III) NPC but less well-established for WHO type I (WHO-I) NPC. Given the rise in oropharyngeal tumors positive for high-risk human papillomavirus (HPV) and the unique biology of WHO-I NPC, we examined the relationship between HPV and WHO-I NPC. Study Design: Retrospective case-comparison study. Methods: A search of a large multidisciplinary cancer center tumor registry identified 183 patients seen from January 1999 to December 2008 with incident NPC and no prior cancer. Available paraffin-embedded tumor specimens (N = 30) were analyzed for oncogenic HPV status by in situ hybridization (ISH) and polymerase chain reaction (PCR) for HPV-16 and HPV-18; EBV status by ISH; and p16 expression by immunohistochemistry. Demographic parameters, including race and smoking, were obtained from the medical records. Results: Among the 18 WHO-I NPC patients, 66% (N = 12) were smokers and 17% (N = 3) Asian; among the 165 WHO-II/III NPC patients, 44% (N = 73) were smokers and 24% (N = 39) Asian. Eight WHO-I NPC patients had available paraffin blocks; five of six were HPV-16-positive by PCR and four of eight were HPV-positive by ISH; only two of eight (25%) were EBV-positive. Twenty-two WHO-II/III NPC patients had available paraffin blocks; only 1 was HPV-positive by ISH, and 13 of 22 (60%) were EBV-positive. Conclusions: These results suggest that WHO-I NPC is associated with oncogenic HPV, although larger studies are needed to verify these findings. Laryngoscope, 2010 [source] | |||||||||||||