Home About us Contact
|
Home About us Contact | ||
|
|
||
Aging Research (aging + research)
Selected AbstractsCalorie restriction effects on silencing and recombination at the yeast rDNAAGING CELL, Issue 6 2009Daniel L. Smith Jr Summary Aging research has developed rapidly over the past decade, identifying individual genes and molecular mechanisms of the aging process through the use of model organisms and high throughput technologies. Calorie restriction (CR) is the most widely researched environmental manipulation that extends lifespan. Activation of the NAD+ -dependent protein deacetylase Sir2 (Silent Information Regulator 2) has been proposed to mediate the beneficial effects of CR in the budding yeast Saccharomyces cerevisiae, as well as other organisms. Here, we show that in contrast to previous reports, Sir2 is not stimulated by CR to strengthen silencing of multiple reporter genes in the rDNA of S. cerevisiae. CR does modestly reduce the frequency of rDNA recombination, although in a SIR2 -independent manner. CR-mediated repression of rDNA recombination also does not correlate with the silencing of Pol II-transcribed noncoding RNAs derived from the rDNA intergenic spacer, suggesting that additional silencing-independent pathways function in lifespan regulation. [source] Some highlights of research on aging with invertebrates, 2008AGING CELL, Issue 5 2008Linda Partridge Summary This annual review focuses on invertebrate model organisms, which shed light on new mechanisms in aging and provide excellent systems for in-depth analysis. This year, the first quantitative estimate of evolutionary conservation of genetic effects on lifespan has pointed to the key importance of genes involved in protein synthesis, a finding confirmed and extended by experimental work. Work in Caenorhabditis elegans and Drosophila has highlighted the importance of phase 2 detoxification in extension of lifespan by reduced insulin/Igf-like signalling. Thorough characterization of systems for dietary restriction in C. elegans is starting to show differences in the mechanisms by which these interventions extend lifespan and has revealed a requirement for autophagy. The response to heat shock in C. elegans turns out to be systemic, and mediated by sensory neurons, with potentially interesting implications for the response of lifespan to temperature. Work in Escherichia coli and yeast has revealed a role for retention of aggregated proteins in the parent in the rejuvenation of offspring while, as in C. elegans, removal of the germ line in Drosophila turns out to extend lifespan. Aging research has suffered the loss of a great scientific leader, Seymour Benzer, and his trail-blazing work on aging and neurodegeneration is highlighted. [source] Annual fishes of the genus Nothobranchius as a model system for aging researchAGING CELL, Issue 5 2005Tyrone Genade Summary Aging research in vertebrates is hampered by the lack of short-lived models. Annual fishes of the genus Nothobranchius live in East African seasonal ponds. Their life expectancy in the wild is limited by the duration of the wet season and their lifespan in captivity is also short. Nothobranchius are popular aquarium fishes and many different species are kept as captive strains, providing rich material for comparative studies. The present paper aims at reviving the interest in these fishes by reporting that: (1) Nothobranchius can be cultured, and their eggs stored dry at room temperature for months or years, offering inexpensive methods of embryo storage; (2) Nothobranchius show accelerated growth and expression of aging biomarkers at the level of histology and behaviour; (3) the species Nothobranchius furzeri has a maximum lifespan of only 3 months and offers the possibility to perform investigations thus far unthinkable in a vertebrate, such as drug screening with life-long pharmacological treatments and experimental evolution; (4) when the lifespan of different species is compared, a general correlation is found between wet season duration in their natural habitat and longevity in captivity; and (5) vertebrate aging-related genes, such as p66Shc and MTP, can be easily isolated in Nothobranchius by homology cloning. These fishes can become excellent models for aging studies. They can be employed to test the effects of experimental manipulation on aging at a pace comparable with that of Drosophila and to probe the effects of natural selection on the evolution of aging-related genes. [source] Electrochemistry of Nucleic Acids at Solid Electrodes and Its ApplicationsELECTROANALYSIS, Issue 15 2004Patricia de-los-Santos-Álvarez Abstract The knowledge of the redox chemistry of nucleic acids (NA) is of paramount importance in cancer and aging research. Charge migration through DNA is also involved in biologically relevant functions such as DNA damage and repair. In the first part of this article the main aspects of the electrochemistry of nucleic acids at solid electrodes are revised, including redox processes, photoelectroactivity and electrical conductivity. In the second part, an overview of its applications is presented. Methods for electrochemical detection of NA, NA-based biosensors for detection of nonnucleic acid molecules, studies on the nature and dynamics of interactions and structural conformations of NA, are some applications that take advantage of NA electrochemistry at solid electrodes. [source] Recent advances in vertebrate aging research 2009AGING CELL, Issue 3 2010Steven Austad Summary Among the notable trends seen in this year's highlights in mammalian aging research is an awakening of interest in the assessment of age-related measures of mouse health in addition to the traditional focus on longevity. One finding of note is that overexpression of telomerase extended life and improved several indices of health in mice that had previously been genetically rendered cancer resistant. In another study, resveratrol supplementation led to amelioration of several degenerative conditions without affecting mouse lifespan. A primate dietary restriction (DR) study found that restriction led to major improvements in glucoregulatory status along with provocative but less striking effects on survival. Visceral fat removal in rats improved their survival, although not as dramatically as DR. An unexpected result showing the power of genetic background effects was that DR shortened the lifespan of long-lived mice bearing Prop1df, whereas a previous report in a different background had found DR to extend the lifespan of Prop1df mice. Treatment with the mammalian target of rapamycin (mTOR) inhibitor, rapamycin, enhanced the survival of even elderly mice and improved their vaccine response. Genetic inhibition of a TOR target made female, but not male, mice live longer. This year saw the mTOR network firmly established as a major modulator of mammalian lifespan. [source] Advances in vertebrate aging research 2007AGING CELL, Issue 2 2008Steven Austad Summary Among this year's highlights in vertebrate aging research, we find a study in which, contrary to the oxidative stress hypothesis of aging, reduced expression of a major cellular antioxidant, glutathione peroxidase 4, led to a small increase in mouse lifespan. By contrast, a large comparative proteomic analysis discovered a remarkably robust and previous unsuspected inverse association between species lifespan and relative frequency of cysteine residues in mitochondrially encoded respiratory chain proteins only, which the authors attribute to cysteine's ease of oxidation. Another study evaluated more cleanly than any previous work the hypothesis that blood glucose concentration is a key mediator of aging, and concluded that it wasn't. Several new mouse longevity mutants were also reported this year, some (PAPP-A, IRS-1, and IRS-2 knockouts) supporting previous work on the importance of insulin/insulin-like growth factor-1 signaling and aging. However, there were inconsistencies between laboratories in some of the results, which merit further investigation. Also, somewhat inconsistent with these findings, over-expression of insulin-like growth factor-1 in heart only lengthened life. From a completely new direction, type 5 adenylyl cyclase knockout mice were observed to live more than 30% longer than controls. Finally, a new program for evaluating potential pharmaceutical interventions in aging and longevity made its appearance, and is notable at this point chiefly for the excellence of its experimental design. A similar program for the disinterested evaluation of reported longevity mutations in mice would be a service to the community of vertebrate aging researchers. [source] Correlations between physiology and lifespan , two widely ignored problems with comparative studiesAGING CELL, Issue 4 2005John R. Speakman Summary Comparative differences between species provide a powerful source of information that may inform our understanding of the aging process. However, two problems regularly attend such analyses. The co-variation of traits with body mass is frequently ignored, along with the lack of independence of the data due to a shared phylogenetic history. These problems undermine the use of simple correlations between various factors and maximum lifespan potential (MLSP) across different species as evidence that the factors in question have causal effects on aging. Both of these problems have been widely addressed by comparative biologists working in fields other than aging research, and statistical solutions to these issues are available. Using these statistical approaches, of making analyses of residual traits with the effects of body mass removed, and deriving phylogenetically independent contrasts, will allow analyses of the relationships between physiology and maximum lifespan potential to proceed unhindered by these difficulties, potentially leading to many useful insights into the aging process. [source] Skeletal Estimation and Identification in American and East European Populations,JOURNAL OF FORENSIC SCIENCES, Issue 3 2008Erin H. Kimmerle Ph.D. Abstract:, Forensic science is a fundamental transitional justice issue as it is imperative for providing physical evidence of crimes committed and a framework for interpreting evidence and prosecuting violations to International Humanitarian Law (IHL). The evaluation of evidence presented in IHL trials and the outcomes various rulings by such courts have in regard to the accuracy or validity of methods applied in future investigations is necessary to ensure scientific quality. Accounting for biological and statistical variation in the methods applied across populations and the ways in which such evidence is used in varying judicial systems is important because of the increasing amount of international forensic casework being done globally. Population variation or the perceived effect of such variation on the accuracy and reliability of methods is important as it may alter trial outcomes, and debates about the scientific basis for human variation are now making their way into international courtrooms. Anthropological data on population size (i.e., the minimum number of individuals in a grave), demographic structure (i.e., the age and sex distribution of victims), individual methods applied for identification, and general methods of excavation and trauma analysis have provided key evidence in cases of IHL. More generally, the question of population variation and the applicability of demographic methods for estimating individual and population variables is important for American and International casework in the face of regional population variation, immigrant populations, ethnic diversity, and secular changes. The reliability of various skeletal aging methods has been questioned in trials prosecuted by the International Criminal Tribunal for the Former Yugoslavia (ICTY) in The Prosecutor of the Tribunal against Radislav Krsti, (Case No. IT-98-33, Trial Judgment) and again in the currently ongoing trial of The Prosecutor of the Tribunal against Zdravko Tolimir, Radivolje Mileti,, Milan Gvero, Vinko Pandurevi,, Ljubisa Beara, Vujadin Popovi,, Drago Nikoli,, Milorad Trbi,, Ljubomir Borovcanin (IT-05-88-PT, Second Amended Indictment). Following the trial of General Krsti,, a collaborative research project was developed between the Forensic Anthropology Center at The University of Tennessee (UT) and the United Nations, International Criminal Tribunal for the Former Yugoslavia, Office of the Prosecutor (ICTY). The purpose of that collaboration was to investigate methods used for the demographic analysis of forensic evidence and where appropriate to recalibrate methods for individual estimation of age, sex, and stature for specific use in the regions of the former Yugoslavia. The question of "local standards" and challenges to the reliability of current anthropological methods for biological profiling in international trials of IHL, as well as the performance of such methods to meet the evidentiary standards used by international tribunals is investigated. Anthropological methods for estimating demographic parameters are reviewed. An overview of the ICTY-UT collaboration for research aimed at addressing specific legal issues is discussed and sample reliability for Balkan aging research is tested. The methods currently used throughout the Balkans are discussed and estimated demographic parameters obtained through medico-legal death investigations are compared with identified cases. Based on this investigation, recommendations for improving international protocols for evidence collection, presentation, and research are outlined. [source] Clinical and histopathological evaluation of 13 cases of adenocarcinoma in aged rhesus macaques (Macaca mulatta)JOURNAL OF MEDICAL PRIMATOLOGY, Issue 2 2002N.A. Rodriguez In recent years, the emphasis on aging research, has led to an increase in the number of aged macaques being maintained in some research facilities with a subsequent increase in the occurrence of age-related diseases. One of the most commonly reported age related diseases is intestinal adenocarcinoma. At the University of Illinois at Chicago (UIC), which maintains a colony of approximately 55 aged rhesus macaques 13 cases of intestinal adenocarcinoma were diagnosed within a 25-month period. This report provides a comprehensive description of the clinical findings for intestinal adenocarcinoma in aged rhesus macaques, including results from physical examinations, laboratory tests, radiographic evaluations, gross and histopathologic findings as well as a comparison with the disease condition in humans. The use of carcinoembryonic antigen as a potential tumor marker was evaluated by immunohistochemical analysis of tissue specimens in 10 cases. Intestinal adenocarcinoma is a disease condition that should be of concern to individuals responsible for the care of aged rhesus macaques. [source] Mass spectrometry in aging researchMASS SPECTROMETRY REVIEWS, Issue 5 2005Christian Schöneich Abstract This review covers the application of mass spectrometric techniques to aging research. Modern proteomic strategies will be discussed as well as the targeted analysis of specific proteins for the correlation of post-translational modifications with protein function. Selected examples will show both the power and also current limitations of the respective techniques. Experimental results and strategies are discussed in view of current theories of the aging process. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 24:701,718, 2005 [source] | ||||||||||