23 research outputs found
Karyotypic evolutions of cancer species in rats during the long latent periods after injection of nitrosourea
Community Violence and Youth: Affect, Behavior, Substance Use, and Academics
Community violence is recognized as a major public health problem (WHO, World Report on Violence and Health,2002) that Americans increasingly understand has adverse implications beyond inner-cities. However, the majority of research on chronic community violence exposure focuses on ethnic minority, impoverished, and/or crime-ridden communities while treatment and prevention focuses on the perpetrators of the violence, not on the youth who are its direct or indirect victims. School-based treatment and preventive interventions are needed for children at elevated risk for exposure to community violence. In preparation, a longitudinal, community epidemiological study, The Multiple Opportunities to Reach Excellence (MORE) Project, is being fielded to address some of the methodological weaknesses presented in previous studies. This study was designed to better understand the impact of children’s chronic exposure to community violence on their emotional, behavioral, substance use, and academic functioning with an overarching goal to identify malleable risk and protective factors which can be targeted in preventive and intervention programs. This paper describes the MORE Project, its conceptual underpinnings, goals, and methodology, as well as implications for treatment and preventive interventions and future research
Changes to the Fossil Record of Insects through Fifteen Years of Discovery
The first and last occurrences of hexapod families in the fossil record are compiled from publications up to end-2009. The major features of these data are compared with those of previous datasets (1993 and 1994). About a third of families (>400) are new to the fossil record since 1994, over half of the earlier, existing families have experienced changes in their known stratigraphic range and only about ten percent have unchanged ranges. Despite these significant additions to knowledge, the broad pattern of described richness through time remains similar, with described richness increasing steadily through geological history and a shift in dominant taxa, from Palaeoptera and Polyneoptera to Paraneoptera and Holometabola, after the Palaeozoic. However, after detrending, described richness is not well correlated with the earlier datasets, indicating significant changes in shorter-term patterns. There is reduced Palaeozoic richness, peaking at a different time, and a less pronounced Permian decline. A pronounced Triassic peak and decline is shown, and the plateau from the mid Early Cretaceous to the end of the period remains, albeit at substantially higher richness compared to earlier datasets. Origination and extinction rates are broadly similar to before, with a broad decline in both through time but episodic peaks, including end-Permian turnover. Origination more consistently exceeds extinction compared to previous datasets and exceptions are mainly in the Palaeozoic. These changes suggest that some inferences about causal mechanisms in insect macroevolution are likely to differ as well
Species diversity in bee flies and hover flies (Diptera: Bombyliidae and Syrphidae) in the horticultural environments of the Blue Mountains, Australia
Flies (Diptera) are one of the most important groups of insect pollinators. Families Bombyliidae (bee flies) and Syrphidae (hover flies) are globally distributed with aproximately 5000 and 6200 described species, respectively. Many studies have attempted to quantify Syrphidae diversity in natural and agricultural environments, due to their perceived value as pollinators, decomposers of organic waste and agents of pest control. However, to date, there have been only two studies of Syrphidae communities in Australia, both of which focused on arable crops. Meanwhile, there have been very few studies of Bombyliidae diversity and none in Australia, despite the fact that bombyliid diversity can be high, far exceeding that of Syrphidae in some ecosystems. We aimed to learn more about Australia's anthophilous Diptera and their diversity in agricultural and native ecosystems. Using a combination of pan trapping and observation plot surveys, we assessed bombyliid and syrphid diversity at Bilpin, New South Wales, Australia, an important horticultural area within the Greater Blue Mountains World Heritage Area. Five syrphid species made up 62% of all individuals collected, while 22 species made up the remaining 32%, including nine species of Bombyliidae. The hover fly Melangyna viridiceps alone accounted for a third of all captured specimens. The larvae of the five most commonly encountered species are all aphidophagous. As such, aphidophagous species appear to be numerically dominant, and this is consistent with previous studies in south-east Australian agroecosystems. M. viridiceps and Triglyphus fulvicornis were frequent visitors to flowering fruit trees and may therefore contribute to the pollination of these crops. However, most visited flowers were introduced weeds or escaped crop plants. The maintenance of diverse floral resources, which may include weeds, is important for sustaining populations of aphidophagous Syrphidae, which may contribute to both pollination and pest control. As a consequence, we recommend a more tolerant approach to weed management in orchards to better facilitate the ecosystem services provided by Diptera
Interactions between TNF and GnRH
Tumour necrosis factor (TNF) ligand members and their associated TNF receptor (TNFR) superfamilies have many diverse physiological roles. TNF is thought to play a critical role in the pathophysiology of a range of diseases including refractory asthma, sepsis, ankylosing spondylitis, lupus, type II diabetes, multiple sclerosis and psoriasis. The recent continued expansion of the novel anti-TNF therapeutic agents (etanercept and infliximab) has seen major improvements in the treatment of some inflammatory-based human diseases including notably rheumatoid arthritis and Crohn’s disease, with other conditions currently being trialled using anti-TNF agents. The cellular signalling machinery used by TNFRs to achieve their many cellular responses are discussed, as is the gonadotrophin-releasing hormone (GnRH) receptor signalling mechanisms. TNF is known to have many actions throughout the body including effects on the hypothalamic-pituitary-adrenal/gonadal axes, with many anti-gonadotrophic effects including a role in the development of endometriosis. These interactions between TNF, GnRH and gonadotrophs are discussed
Selective Protection of Human Liver Tissue in TNF-Targeting of Cancers of the Liver by Transient Depletion of Adenosine Triphosphate
Background
Tumor necrosis factor alpha (TNF) is able to kill cancer cells via receptor-mediated cell death requiring adenosine triphosphate (ATP). Clinical usage of TNF so far is largely limited by its profound hepatotoxicity. Recently, it was found in the murine system that specific protection of hepatocytes against TNF's detrimental effects can be achieved by fructose-mediated ATP depletion therein. Before employing this quite attractive selection principle in a first clinical trial, we here comprehensively investigated the interdependence between ATP depletion and TNF hepatotoxicity in both in vitro and ex vivo experiments based on usage of primary patient tissue materials.
Methods
Primary human hepatocytes, and both non-tumorous and tumorous patient-derived primary liver tissue slices were used to elucidate fructose-induced ATP depletion and TNF-induced cytotoxicity.
Results
PHH as well as tissue slices prepared from non-malignant human liver specimen undergoing a fructose-mediated ATP depletion were both demonstrated to be protected against TNF-induced cell death. In contrast, due to tumor-specific overexpression of hexokinase II, which imposes a profound bypass on hepatocytic-specific fructose catabolism, this was not the case for human tumorous liver tissues.
Conclusion
Normal human liver tissues can be protected transiently against TNF-induced cell death by systemic pretreatment with fructose used in non-toxic/physiologic concentrations. Selective TNF-targeting of primary and secondary tumors of the liver by transient and specific depletion of hepatocytic ATP opens up a new clinical avenue for the TNF-based treatment of liver cancers.ISSN:1932-620
Independent specialization of the human and mouse X chromosomes for the male germ line
We compared the human and mouse X chromosomes to systematically test Ohno's law, which states that the gene content of X chromosomes is conserved across placental mammals. First, we improved the accuracy of the human X-chromosome reference sequence through single-haplotype sequencing of ampliconic regions. The new sequence closed gaps in the reference sequence, corrected previously misassembled regions and identified new palindromic amplicons. Our subsequent analysis led us to conclude that the evolution of human and mouse X chromosomes was bimodal. In accord with Ohno's law, 94–95% of X-linked single-copy genes are shared by humans and mice; most are expressed in both sexes. Notably, most X-ampliconic genes are exceptions to Ohno's law: only 31% of human and 22% of mouse X-ampliconic genes had orthologs in the other species. X-ampliconic genes are expressed predominantly in testicular germ cells, and many were independently acquired since divergence from the common ancestor of humans and mice, specializing portions of their X chromosomes for sperm production.National Institutes of Health (U.S.)Howard Hughes Medical Institut