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Biological Changes (biological + change)
Selected AbstractsVariation in the TNF Gene Promoter and Risk of Osteolysis After Total Hip ArthroplastyJOURNAL OF BONE AND MINERAL RESEARCH, Issue 11 2003FRCS, J Mark Wilkinson PhD Abstract Genetic factors may influence implant failure caused by osteolysis after THA. In an association study of 481 subjects after THA, we found that carriage of the TNF - 238A allele was associated with an increased incidence of osteolysis versus noncarriage (odds ratio, 1.7) and was independent of other risk factors. Genetic and environmental factors influence implant survival after THA. Introduction: Tumor necrosis factor (TNF) is thought to play a role in osteolysis, the major cause of implant failure after total hip arthroplasty (THA). Natural sequence variations at ,238 and ,308 in the TNF gene promoter are associated with differences in susceptibility to several TNF-mediated diseases. We tested whether these polymorphisms are associated with osteolysis after THA. Materials and Methods: A total of 481 whites (214 with failed versus 267 with intact implants) were recruited 11.7 ± 4 years after cemented THA. Genomic DNA was extracted from peripheral blood and genotyped for the ,238 and ,308 polymorphisms using the Taqman 5, nuclease method. Healthy controls (n = 500) from the background population were also genotyped to establish the local prevalence of these alleles. Results: The carriage of ,238A was 8.8% in the background population and 10.9% in the THA controls (p > 0.05). Carriage of ,238A in the osteolysis group was 17.3% (odds ratio, 1.7; 95% CI, 1.0,2.9). Carriage was highest (20.5%) in patients with more widespread osteolysis (OR, 2.1; 1.2,3.8). The association of ,238A with osteolysis was independent of other risk factors for osteolysis (logistic regression analysis: OR, 1.8; 1.0,3.2). Carriage of ,308A was not associated with osteolysis. Conclusion: Genetic, as well as environmental factors, influence implant failure after THA. Whether the TNF - 238 polymorphism causes a biological change that predisposes to loosening or is in linkage disequilibrium with such a locus is not yet known. [source] DATE analysis: A general theory of biological change applied to microarray dataBIOTECHNOLOGY PROGRESS, Issue 5 2009David Rasnick Abstract In contrast to conventional data mining, which searches for specific subsets of genes (extensive variables) to correlate with specific phenotypes, DATE analysis correlates intensive state variables calculated from the same datasets. At the heart of DATE analysis are two biological equations of state not dependent on genetic pathways. This result distinguishes DATE analysis from other bioinformatics approaches. The dimensionless state variable F quantifies the relative overall cellular activity of test cells compared to well-chosen reference cells. The variable ,i is the fold-change in the expression of the ith gene of test cells relative to reference. It is the fraction , of the genome undergoing differential expression,not the magnitude ,,that controls biological change. The state variable , is equivalent to the control strength of metabolic control analysis. For tractability, DATE analysis assumes a linear system of enzyme-connected networks and exploits the small average contribution of each cellular component. This approach was validated by reproducible values of the state variables F, RNA index, and , calculated from random subsets of transcript microarray data. Using published microarray data, F, RNA index, and , were correlated with: (1) the blood-feeding cycle of the malaria parasite, (2) embryonic development of the fruit fly, (3) temperature adaptation of Killifish, (4) exponential growth of cultured S. pneumoniae, and (5) human cancers. DATE analysis was applied to aCGH data from the great apes. A good example of the power of DATE analysis is its application to genomically unstable cancers, which have been refractory to data mining strategies. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Climate change, genotypic diversity and gene flow in reef-building coralsECOLOGY LETTERS, Issue 4 2004David J. Ayre Abstract In the ocean, large-scale dispersal and replenishment by larvae is a key process underlying biological changes associated with global warming. On tropical reefs, coral bleaching, degradation of habitat and declining adult stocks are also likely to change contemporary patterns of dispersal and gene flow and may lead to range contractions or expansions. On the Great Barrier Reef, where adjacent reefs form a highly interconnected system, we use allozyme surveys of c. 3000 coral colonies to show that populations are genetically diverse, and rates of gene flow for a suite of five species range from modest to high among reefs up to 1200 km apart. In contrast, 700 km further south on Lord Howe Island, genetic diversity is markedly lower and populations are genetically isolated. The virtual absence of long-distance dispersal of corals to geographically isolated, oceanic reefs renders them extremely vulnerable to global warming, even where local threats are minimal. [source] Can macroinvertebrate rapid bioassessment methods be used to assess river health during drought in south eastern Australian streams?FRESHWATER BIOLOGY, Issue 12 2008PETER ROSE Summary 1Despite significant concern about drought impacts in Australia, there have been no broad-scale studies of drought effects on river health. A severe and prolonged drought has been acting on many streams in south eastern Australia over the past decade. EPA Victoria has undertaken rapid bioassessment (RBA) of over 250 stream reference sites since 1990, providing an opportunity for a before-after-control-impact investigation of drought related changes to macroinvertebrate indices and water quality. This study uses data from 1990 to 2004 to critically evaluate the effectiveness of using RBA methods and indices, which were designed for assessment of human impacts, for monitoring streams during drought. 2Reference stream sites across Victoria (those with minimal anthropogenic disturbances and repeatedly sampled) were classified as being ,in drought' or ,not in drought' using the Bureau of Meteorology's rainfall deficiency definition. Four biological indices (SIGNAL, EPT, Family Richness and AUSRIVAS) were calculated for combined autumn and spring samples for edge and riffle habitats for the selected sites. 3General linear models and paired t -tests were used to detect drought related changes to index and water quality values at state-wide and bioregional scales. Changes in taxa constancy were examined to determine which taxa were sensitive to or benefited from drought conditions. Frequency of site failure against biological objectives specified in the State Environment Protection Policy (Waters of Victoria) (herein termed ,SEPP WoV') before and during drought was also examined to detect changes in a management context. 4Few significant changes in index values were detected for riffle habitat samples. Rates of failure against biological objectives were similar before and during drought for riffle samples. In contrast, edge habitat AUSRIVAS and SIGNAL scores were significantly reduced at the state-wide scale and most indices showed significant declines in the lower altitude forests, and foothills and coastal plains bioregions. 5Generally, more pollution tolerant, lentic taxa replaced sensitive and flow-requiring taxa in edge samples during drought. In contrast, there were few reductions in the taxa of riffle samples during drought. However, many pool preferring, but pollution sensitive taxa occurred more frequently in riffle areas. Hence, the riffle community began to resemble that of pools and edges. This was attributed to decreased flow and increased ,lentic' habitat opportunities in riffles. 6Detection of a drought effect was confined to the edge habitat and site failure could be assigned to drought and anthropogenic impacts, in conjunction or alone. The riffle sampling protocol was resistant to detection of drought effects as samples were only taken when sufficient water was present within this habitat. Therefore, biological changes at sites not meeting policy objectives for riffle habitats can be attributed to anthropogenic rather than drought impacts. [source] INTEGRATED LANDSCAPE ANALYSES OF CHANGE OF MIOMBO WOODLAND IN TANZANIA AND ITS IMPLICATION FOR ENVIRONMENT AND HUMAN LIVELIHOODGEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 1 2009LENNART STRÖMQUIST ABSTRACT. Landscapes bear witness to past and present natural and societal processes influencing the environment and human livelihoods. By analysing landscape change at different spatial scales over time the effects on the environment and human livelihoods of various external and internal driving forces of change can be studied. This paper presents such an analysis of miombo woodland surrounding the Mkata plains in central Tanzania. The rich natural landscape diversity of the study area in combination with its historical and political development makes it an ideal observation ground for this kind of study. The paper focuses on long-term physical and biological changes, mainly based on satellite information but also on field studies and a review of documents and literature. The miombo woodlands are highly dynamic semi-arid ecosystems found on a number of nutrient-poor soil groups. Most of the woodlands are related to an old, low-relief geomorphology of erosion surfaces with relatively deep and leached soils, or to a lesser extent also on escarpments and steep Inselberg slopes with poor soils. Each period in the past has cast its footprints on the landscape development and its potential for a sustainable future use. On a regional level there has been a continual decrease in forest area over time. Expansion of agriculture around planned villages, implemented during the 1970s, in some cases equals the loss of forest area (Mikumi-Ulaya), whilst in other areas (Kitulangalo), the pre-independence loss of woodland was small; the agricultural area was almost the same during the period 1975,1999, despite the fact that forests have been lost at an almost constant rate over the same period. Illegal logging and charcoal production are likely causes because of the proximity to the main highway running through the area. Contrasting to the general regional pattern are the conditions in a traditional village (Ihombwe), with low immigration of people and a maintained knowledge of the resource potential of the forest with regards to edible plants and animals. In this area the local community has control of the forest resources in a Forest Reserve, within which the woody vegetation has increased in spite of an expansion of agriculture on other types of village land. The mapping procedure has shown that factors such as access to transport and lack of local control have caused greater deforestation of certain areas than during the colonial period. Planned villages have furthermore continued to expand over forest areas well after their implementation, rapidly increasing the landscape fragmentation. One possible way to maintain landscape and biodiversity values is by the sustainable use of traditional resources, based on local knowledge of their management as illustrated by the little change observed in the traditionally used area. [source] Insights into electromagnetic interaction mechanismsJOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2002Reba Goodman Low frequency (<,300 Hz) electromagnetic (EM) fields induce biological changes that include effects ranging from increased enzyme reaction rates to increased transcript levels for specific genes. The induction of stress gene HSP70 expression by exposure to EM fields provides insight into how EM fields interact with cells and tissues. Insights into the mechanism(s) are also provided by examination of the interaction of EM fields with moving charges and their influence on enzyme reaction rates in cell-free systems. Biological studies with in vitro model systems have focused, in general, on the nature of the signal transduction pathways involved in response to EM fields. It is likely, however, that EM fields also interact directly with electrons in DNA to stimulate biosynthesis. Identification of an EM field-sensitive DNA sequence in the heat shock 70 (HSP70) promoter, points to the application of EM fields in two biomedical applications: cytoprotection and gene therapy. EM field induction of the stress protein hsp70 may also provide a useful biomarker for establishing a science-based safety standard for the design of cell phones and their transmission towers. © 2002 Wiley-Liss, Inc. [source] Temporary amelioration of bilirubin conjugation defect in Gunn rats by transplanting conditionally immortalized hepatocytesJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 6 2002BYUNG-HO KIM Abstract Background: Conditionally immortalized hepatocytes (CIH) have been used in hepatocyte transplantation as an alternative to primary hepatocytes to cope with the shortage of donor organs. However, CIH are known to undergo apoptosis at body temperature and survive in vivo for a short period. In the present study, we investigated whether CIH function or not and how long their function is maintained in vivo. Methods: Various CIH cell lines that were established with temperature-sensitive Simian virus 40 large T antigen were transplanted into the spleen of Gunn rats, which are defective in bilirubin uridine diphosphate glucuronoside transferase (BUGT). Then, we measured biological changes over 3 months. Results: Serum bilirubin of the syngeneic CIH recipients decreased by 30%, which was maintained for 8 weeks. Thereafter, it began to rise to basal levels. The recipients of allogeneic CIH showed a minor reduction of bilirubin, although this was not statistically significant. However, there was no significant change in the bilirubin level in recipients of BUGT-defective congeneic CIH throughout the study period. Bilirubin monoglucuronides in the bile were not detected in the recipients of BUGT-defective CIH. However, they appeared in recipients of non-defective CIH and made up approximately 41% of total bile pigments. Conclusions: Conditionally immortalized hepatocytes expressed hepatocyte function in vivo as well as in vitro, but the function lasted for a couple of months. According to our previous study, the limited functional duration may be related to the inevitable occurrence of apoptosis of these cells at body temperature. These data suggest that CIH can be used in hepatocyte transplantation only for temporary hepatic support. © 2002 Blackwell Publishing Asia Pty Ltd [source] A full-UV spectrum absorbing daily use cream protects human skin against biological changes occurring in photoagingPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 4 2000S. Seité Background: There is overwhelming evidence that exposure of human skin to ultraviolet radiations (UVR) leads to the development of cutaneous photoaging and eventually to neoplasia. This study was designed to evaluate in humans the protection afforded by a daily use cream containing a photostable combination of UVB and UVA absorbers (Uvinul® N539, Parsol® 1789 and Mexoryl® SX) providing a continuous absorption through the entire UV spectrum, against damages induced by repeated daily exposure to solar simulated radiation (SSR). Methods: Buttock skin of 12 healthy volunteers was exposed 5 days per week for 6 weeks to one minimal erythema dose of solar simulated radiation per exposure. The following parameters in treated and untreated skin were evaluated: erythema, pigmentation, skin hydration, skin microtopography, histology and immunochemistry, and collagen and metalloproteinase (MMP) mRNA levels. Results: In SSR exposed unprotected skin sites, we observed melanization and changes in the skin hydration and microtopography. The epidermis revealed a significant increase in stratum corneum and stratum granulosum thickness. In the dermis, an enhanced expression of tenascin and a reduced expression of type I pro-collagen were evidenced just below the dermal epidermal junction. Although we were unable to visualize any change in elastic fibers in exposed buttock skin, a slightly increased deposition of lysozyme and alpha 1 antitrypsin on these fibers was observed using immunofluorescence techniques. Furthermore, types I and III collagen mRNA were slightly increased and a significant enhancement (up to 2.8-fold) of MMP-2 mRNA level was observed. The daily use cream was shown to prevent all these biological changes. Conclusion: Our results show in vivo that an appropriate full-UV spectrum product significantly reduces the solar-UV-induced skin damage, demonstrating the benefit of daily photoprotection. [source] Remodeling protein complexes: Insights from the AAA+ unfoldase ClpX and Mu transposasePROTEIN SCIENCE, Issue 8 2005Briana M. Burton Abstract Multiprotein complexes in the cell are dynamic entities that are constantly undergoing changes in subunit composition and conformation to carry out their functions. The protein,DNA complex that promotes recombination of the bacteriophage Mu is a prime example of a complex that must undergo specific changes to carry out its function. The Clp/Hsp100 family of AAA+ ATPases plays a critical role in mediating such changes. The Clp/Hsp100 unfolding enzymes have been extensively studied for the roles they play in protein degradation. However, degradation is not the only fate for proteins that come in contact with the ATP-dependent unfolding enzymes. The Clp/Hsp100 enzymes induce structural changes in their substrates. These structural changes, which we refer to as "remodeling," ultimately change the biological activity of the substrate. These biological changes include activation, inactivation (not associated with degradation), and relocation within the cell. Analysis of the interaction between Escherichia coli ClpX unfoldase and the Mu recombination complex, has provided molecular insight into the mechanisms of protein remodeling. We discuss the key mechanistic features of the remodeling reactions promoted by ClpX and possible implications of these findings for other biological reactions. [source] Selection of normalizer genes in conducting relative gene expression analysis of embryosBIRTH DEFECTS RESEARCH, Issue 8 2003Qin J. Zhang Abstract BACKGROUND In relative gene expression analysis, a reference gene for sample normalization is required for determining target expression changes among experimental treatment groups. Since some developmental toxicants secondarily cause general growth retardation and/or other general biological changes, commonly used housekeeping genes may not serve as accurate normalizers. METHODS We conducted real-time polymerase chain reaction (PCR) with normalization to calculate relative target transcriptional change, using housekeeping and structure-specific expression genes as normalizers. Relative levels of Hoxb1 expression were measured in cultured rodent embryos at 24 hr post retinoic acid (RA) administration. Transcriptional response was also evaluated using two novel compounds that produced posterior axial and growth defects in rat whole-embryo culture. Embryos treated with these compounds were evaluated for general biological processes, and their respective biological states were considered in the context of the relative gene expression change calculated with the housekeeping normalizers. RESULTS Normalized RA-induced Hoxb1 expression demonstrated that only some reference genes accurately quantitated the expected 1.5- to 2-fold increase in Hoxb1 expression. Evaluation of the test compounds demonstrated that only normalization with the spatially-restricted hindbrain gene, Krox-20, calculated significant expression decreases of T -gene, a gene known to be functionally relevant in posterior axial development. Reduction in T -gene expression was confirmed qualitatively by whole-mount in situ hybridization. CONCLUSIONS Prudent reference gene selection is important in evaluating relative gene expression in embryos. An experimental control design is proposed to facilitate the identification of normalizing genes that will accurately calculate relative gene expression change in treated embryos. Birth Defects Research (Part A), 2003. © 2003 Wiley-Liss, Inc. [source] Status of Observational Models Used in Design and Control of Products and ProcessesCOMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY, Issue 1 2008Shyam S. Sablani This article is part of a collection entitled "Models for Safety, Quality, and Competitiveness of the Food Processing Sector," published in Comprehensive Reviews in Food Science and Food Safety. It has been peer-reviewed and was written as a follow-up of a pre-IFT workshop, partially funded by the USDA NRI grant 2005-35503-16208. ABSTRACT:, Modeling techniques can play a vital role in developing and characterizing food products and processes. Physical, chemical, and biological changes that take place during food and bioproduct processing are very complex and experimental investigation may not always be possible due to time, cost, effort, and skills needed. In some cases even experiments are not feasible to conduct. Often it is difficult to visualize the complex behavior of a data set. In addition, modeling is a must for process design, optimization, and control. With the rapid development of computer technology over the past few years, more and more food scientists have begun to use computer-aided modeling techniques. Observation-based modeling methods can be very useful where time and resources do not allow complete physics-based understanding of the process. This review discusses the state of selected observation-based modeling techniques in the context of industrial food processing. [source] | ||||||||||||||||