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Severe Damage (severe + damage)
Selected AbstractsSeismic performance of a 3D full-scale high-ductility steel,concrete composite moment-resisting structure,Part I: Design and testing procedureEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 14 2008A. Braconi Abstract A multi-level pseudo-dynamic (PSD) seismic test programme was performed on a full-scale three-bay two-storey steel,concrete composite moment-resisting frame built with partially encased composite columns and partial-strength connections. The system was designed to provide strength and ductility for earthquake resistance with energy dissipation located in ductile components of beam-to-column joints including flexural yielding of beam end-plates and shear yielding of the column web panel zone. In addition, the response of the frame depending on the column base yielding was analysed. Firstly, the design of the test structure is presented in the paper, with particular emphasis on the ductile detailing of beam-to-column joints. Details of the construction of the test structure and the test set-up are also given. The paper then provides a description of the non-linear static and dynamic analytical studies that were carried out to preliminary assess the seismic performance of the test structure and establish a comprehensive multi-level PSD seismic test programme. The resulting test protocol included the application of a spectrum-compatible earthquake ground motion scaled to four different peak ground acceleration levels to reproduce an elastic response as well as serviceability, ultimate, and collapse limit state conditions, respectively. Severe damage to the building was finally induced by a cyclic test with stepwise increasing displacement amplitudes. Copyright © 2008 John Wiley & Sons, Ltd. [source] Influence of UV Radiation on Four Freshwater Invertebrates,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2000Alina Cywinska ABSTRACT Laboratory tests confirmed a negative and variable response of the following four species to artificial UV radiation: Cypridopsis vidua, an ostracode; Chironomus riparius, a midge larvae; Hyalella azteca, an amphipod; and Daphnia magna, a daphnid. Severe damage occurred at UV-B irradiance ranging from 50 to 80% of incident summer values. Under constant exposure to UV and photosynthetically active radiation (PAR) the acute lethal response was recorded at 0.3, 0.8, 0.8 and 4.9 W m,2 UV-B for D. magna, H. azteca, C. riparius and C. vidua, respectively. Sublethal UV-B damage to invertebrates included impaired movement, partial paralysis, changes in pigmentation and altered water balance (bloating). A series of UV-B, UV-A and PAR treatments, applied separately and in combination, revealed a positive role for both UV-A and PAR in slowing down UV-B damage. Mean lethal concentration values of the species typically more tolerant to UV and PAR (Cypridopsis, Chironomus) decreased conspicuously when both UV-A and PAR were eliminated. For UV-B,sensitive species (Hyalella, Daphnia) these differences were notably smaller. We suggest that this gradation of sensitivity among the tested species demonstrates potential differences in repairing mechanisms which seem to work more efficiently for ostracodes and chironomids than for amphipods and daphnids. Manipulations with a cellulose acetate filter showed that lower range UV-B (280,290 nm), produced by FS-40 lamps, may cause excessive UV damage to invertebrates. [source] Impaired Heart Function And Noradrenaline Release After Ischaemia In Stroke-Prone Spontaneously Hypertensive RatsCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 9 2000Hong Chen SUMMARY 1. Stroke-prone spontaneously hypertensive rats (SHRSP) are a strain of rat that exhibit severely high blood pressure and stroke attacks at an early age, but their heart function in vitro has seldom been studied in detail. Although the activity of the sympathetic nervous system is known to increase after myocardial ischaemia, there is little information about the cardiac release of noradrenaline (NA) associated with heart function after ischaemia in SHRSP. The aim of the present study was to examine heart function and cardiac NA release after ischaemia in SHRSP. 2. Isolated hearts of 4- and 8-month-old SHRSP and age-matched Wistar-Kyoto (WKY) rats were perfused in a working heart preparation and were subjected to 30 min ischaemia followed by 30 min reperfusion. Heart function and coronary flow were monitored throughout the experiment. Coronary effluent was collected for determination of NA using high- performance liquid chromatography coupled with electrochemical detection. 3. Under baseline conditions, cardiac output of 4-month-old SHRSP was slightly but significantly decreased compared with that of WKY rats (P < 0.05), although coronary flow was maintained normally at this age. Eight-month-old SHRSP showed a further impairment of systolic heart function, with lower coronary flow and higher coronary vascular resistance under baseline conditions. Elevated left ventricular end-diastolic pressure was evident in SHRSP at both ages before ischaemia. Heart function was severely damaged after 30 min global ischaemia in SHRSP from both age groups. Stroke-prone spontaneously hypertensive rats also showed lower coronary flow and higher coronary vascular resistance during reperfusion. 4. Coronary NA was not detectable in WKY rats or SHRSP at 4 months of age under baseline conditions. In 8-month-old SHRSP, pre-ischaemic NA release was significantly higher than that in age-matched WKY rat controls. The concentration of NA in the coronary effluent of SHRSP during reperfusion was also significantly higher than that of WKY rats at both ages. 5. These data demonstrate that SHRSP have early impairment of both systolic and diastolic heart function compared with WKY rats. Severe damage of heart function and coronary flow after ischaemia in SHRSP was accompanied with an increased release of NA, which may play a harmful role in heart function impairment in SHRSP after ischaemia. [source] Severe periodontal damage by an ultrasonic endodontic device: a case reportDENTAL TRAUMATOLOGY, Issue 2 2007John D. Walters Abstract,,, Heat produced within a root canal during use of an ultrasonic instrument can be conducted through the dentin into periodontal ligament, bone and soft tissue. If severe in intensity or long in duration, it can induce damage to these tissues. This report describes a case in which an ultrasonic endodontic instrument apparently induced severe damage to alveolar bone, gingiva and nasal mucosa in a 42-year-old female. Overheating of a maxillary central incisor caused necrosis of soft tissue and bone on the facial and mesial aspects and triggered a protracted inflammatory response in the adjacent nasal cavity. To relieve the severe discomfort associated with this damage, the patient chose to have her maxillary incisors extracted and replaced by a removable partial denture. A defect in the soft tissue and bone was present at a follow-up visit 10 months after the extractions. While morbidity of this nature is rare, this case reinforces the need to maintain adequate cooling of ultrasonic instruments. [source] Evidence for low-titre infections in insect symbiosis: Wolbachia in the bark beetle Pityogenes chalcographus (Coleoptera, Scolytinae)ENVIRONMENTAL MICROBIOLOGY, Issue 8 2009Arthofer Wolfgang Summary Wolbachia are obligatory endosymbiotic ,-proteobacteria found in many insect species. They are maternally transmitted and often exhibit reproductive phenotypes like cytoplasmic incompatibility. Pityogenes chalcographus is a bark beetle causing severe damage in spruce stands. Its European populations are divided into several mitochondrial clades separated by partial crossing barriers. In this study, we tested a large sample set covering the natural range of the beetle in Europe for the presence of Wolbachia and associations between infection pattern and mitotypes using a highly sensitive nested PCR technique. 35.5% of the individuals were infected with the endosymbiont and two distinct strains were identified. Both strains occur in low titre not accessible by conventional detection methods. The infections are present all over Europe, unlikely to cause the partial crossing barriers in this host and uncoupled from mitochondrial clades. This pattern is indicative for populations evolving towards endosymbiont loss and for repeated intraspecific horizontal transfer of Wolbachia. Alternatively, the low-titre infections found in P. chalcographus are yet another example for Wolbachia that can persist in host species at low densities and frequencies. [source] A review of research to address carrot fly (Psila rosae) control in the UK,EPPO BULLETIN, Issue 2 2009R. Collier Carrot fly (Psila rosae) is a serious pest of umbelliferous crops such as carrot, parsnip, celery and parsley. Carrot fly has been studied in the UK for more than 60 years. Whilst some of these studies have been focused on insecticides, others have demonstrated the potential for non-insecticidal methods of control that might contribute to an integrated pest management strategy. These include rotation and spatial separation of susceptible crops; carrot varieties with partial resistance to carrot fly; and crop management strategies to avoid oviposition or the development of severe damage. This paper outlines some of the approaches that have been taken and indicates how these are, or might be, used in practice. [source] An enteroaggregative Escherichia coli strain of serotype O111:H12 damages and invades cultured T84 cells and human colonic mucosaFEMS MICROBIOLOGY LETTERS, Issue 2 2001Cecilia M. Abe Abstract The pathogenic mechanisms of enteroaggregative Escherichia coli (EAEC) are not well defined. We investigated the interaction of EAEC strain 236 (serotype O111:H12) with polarised Caco-2 and T84 human intestinal epithelial cells lines, and with human jejunal and colonic mucosa. Strain 236 adhered to both polarised cell lines and to both intestinal tissue types, but caused severe damage and was invasive only in T84 cells and colonic mucosa. In contrast, prototype EAEC strain 042, which also adhered to the cultured intestinal cell lines, did not adhere to or invade jejunal or colonic tissue. These observations suggest a heterogeneity of virulence properties within the EAEC category of diarrhoea-causing E. coli. [source] Test method for concrete spalling using small electric furnaceFIRE AND MATERIALS, Issue 4 2010Ren Zhao Abstract Concrete spalling can cause severe damage to concrete structure when exposed to fire. The spalling mechanisms are not very well understood. For the testing of spalling, full-scale structural members should be used, as spalling tests are sensitive to size effects. Full-scale testing in large furnace is costly and is not suitable for testing large number of concrete mixture trials. The standard and hydrocarbon fire time,temperature curves have rapid temperature rise during the initial phase. This temperature rise requires a gas furnace with high heating capacity and cannot be generated by electric muffle furnace commonly available in many laboratories. This paper presents a method to carry out spalling test in small-scale specimens with exposure to rapid temperature rise using a commonly available electric furnace in the laboratories. The tests are based on 150,mm diameter cylinders that are laterally confined to simulate full-scale structural members. The cylinder surface is exposed to rapid temperature rise by exposing through vertical and/or horizontal holes in pre-heated small electric furnace. Some unconfined 100,mm diameter cylinders were also exposed horizontally to test the performance of confinement. The paper shows that the hydrocarbon fire and standard fire exposure can be simulated by manipulating the exposure location of the surface of the concrete cylinder. Ordinary Portland cement concrete cylinders with different strengths were tested and different spalling patterns were observed. The spalling patterns matched the test results from a gas furnace fire test simulating the fire curves. The tests demonstrated that the method is an effective and convenient technique to predict the spalling risk of a concrete. Copyright © 2009 John Wiley & Sons, Ltd. [source] Differential regulation of trophic and proinflammatory microglial effectors is dependent on severity of neuronal injuryGLIA, Issue 3 2008Aaron Y. Lai Abstract Microglial activation has been reported to promote neurotoxicity and also neuroprotective effects. A possible contributor to this dichotomy of responses may be the degree to which proximal neurons are injured. The aim of this study was to determine whether varying the severity of neuronal injury influenced whether microglia were neuroprotective or neurotoxic. We exposed cortical neuronal cultures to varying degrees of hypoxia thereby generating mild (<20% death, 30min hypoxia), moderate (40,60% death, 2 h hypoxia), or severe (>70% death, 6 h hypoxia) injuries. Twenty-four hours after hypoxia, the media from the neuronal cultures was collected and incubated with primary microglial cultures for 24 h. Results showed that the classic microglial proinflammatory mediators including inducible nitric oxide synthase, tumor necrosis factor ,, and interleukin-1-, were upregulated only in response to mild neuronal injuries, while the trophic microglial effectors brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor were upregulated in response to all degrees of neuronal injury. Microglia stimulated with media from damaged neurons were co-cultured with hypoxic neurons. Microglia stimulated by moderate, but not mild or severe damage were neuroprotective in these co-cultures. We also showed that the severity-dependent phenomenon was not related to autocrine microglial signaling and was dependent on the neurotransmitters released by neurons after injury, namely glutamate and adenosine 5,-triphosphate. Together our results show that severity of neuronal injury is an important factor in determining microglial release of "toxic" versus "protective" effectors and the resulting neurotoxicity versus neuroprotection. © 2007 Wiley-Liss, Inc. [source] Effect of propranolol on the factors promoting bacterial translocation in cirrhotic rats with ascitesHEPATOLOGY, Issue 1 2000María Pérez-Paramo Bacterial translocation appears to be an important mechanism in the pathogenesis of spontaneous infections in cirrhosis. Cirrhotic patients are commonly treated with ,-adrenoceptor blockers, but the impact of this treatment in the factors promoting bacterial translocation has not been investigated. This study was aimed at investigating in cirrhotic rats with ascites the effect of propranolol on intestinal bacterial load, transit, and permeability of the bowel and on the rate of bacterial translocation. Bacterial translocation to mesenteric lymph nodes and intestinal bacterial overgrowth, permeability (urinary excretion of 99mTc-diethylenetriaminepentaacetic acid [99mTc-DTPA]), and transit (geometric center ratio of 51Cr) were assessed in 29 rats with carbon tetrachloride (CCl4 ) cirrhosis and 20 controls. These variables were then measured in 12 placebo- and in 13 propranolol-treated ascitic cirrhotic rats. Bacterial translocation was present in 48% of the cirrhotic rats and in none of the controls. Cirrhotic rats with intestinal bacterial overgrowth had a significantly higher rate of translocation and slower intestinal transit than those without it. Among the 15 rats with overgrowth and a 99mTc-DTPA excretion greater than 10%, 15 had translocation and 2 had bacterial peritonitis. Only 1 of the 14 rats with either intestinal overgrowth or a 99mTc-DTPA excretion greater than 10% presented translocation. Compared with the placebo group, propranolol-treated animals had significantly lower portal pressure, faster intestinal transit, and lower rates of bacterial overgrowth and translocation. In ascitic cirrhotic rats, bacterial translocation results from intestinal overgrowth and severe damage to gut permeability. In this setting, intestinal overgrowth is associated with intestinal hypomotility. Propranolol accelerates the intestinal transit, decreasing the rates of bacterial overgrowth and translocation. [source] Unstructured grid generation using LiDAR data for urban flood inundation modellingHYDROLOGICAL PROCESSES, Issue 11 2010Ryota Tsubaki Abstract Inundation disasters, caused by sudden water level rise or rapid flow, occur frequently in various parts of the world. Such catastrophes strike not only in thinly populated flood plains or farmland but also in highly populated villages or urban areas. Inundation of the populated areas causes severe damage to the economy, injury, and loss of life; therefore, a proper management scheme for the disaster has to be developed. To predict and manage such adversity, an understanding of the dynamic processes of inundation flow is necessary because risk estimation is performed based on inundation flow information. In this study, we developed a comprehensive method to conduct detailed inundation flow simulations for a populated area with quite complex topographical features using LiDAR (Light Detection and Ranging) data. Detailed geospatial information including the location and shape of each building was extracted from the LiDAR data and used for the grid generation. The developed approach can distinguish buildings from vegetation and treat them differently in the flow model. With this method, a fine unstructured grid can be generated representing the complicated urban land features precisely without exhausting labour for data preparation. The accuracy of the generated grid with different grid spacing and grid type is discussed and the optimal range of grid spacing for direct representation of urban topography is investigated. The developed method is applied to the estimation of inundation flows, which occurred in the basin of the Shin-minato River. A detailed inundation flow structure is represented by the flow model, and the flow characteristics with respect to topographic features are discussed. Copyright © 2010 John Wiley & Sons, Ltd. [source] Wind speed measurements and forest damage in Canton Zurich (Central Europe) from 1891 to winter 2007INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 3 2010Tilo Usbeck Abstract The most severe damage to forests in central Europe occurs during winter storms that are caused by Northern Hemispheric mid-latitude cyclones. These winter storms have caused several catastrophic windthrows during the past four decades. Amounts of forest storm damage are believed to be a function of both the size of the forest and the storm intensity. To test this hypothesis, the Zurich region (city and canton) was chosen because long-term climate observation data is available for the region. The relationships between forest attributes, wind speed and forest damage were explored by comparing data on forests and wind speed from 107 winters with forest damage. Storm damage was defined as the proportion of damaged forests with respect to the growing stock. The variables: daily wind run (91 years), daily maximum hourly average wind speed (107 years) and peak gust wind speed (74 years) were homogenized with respect to high wind speed and related to levels of forest damage. High maximum wind speed at the end of the 19th century and at the beginning of the 20th century was followed by low maximum wind speed in the 1940s, 1960s and 1970s. Since then, maximum values have increased. Gusts (extremes of the maximum wind speed) increased from the beginning of the recordings in 1933 and peaked in the early 1990s. Forest damage due to winter storms is best correlated with peak wind speed. Gusts exceeding 40 m/s and resulting in catastrophic windthrow have increased in recent winters. Copyright © 2009 Royal Meteorological Society [source] Volume recovery, surface properties and membrane integrity of Lactobacillus delbrueckii subsp. bulgaricus dehydrated in the presence of trehalose or sucroseJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2007E.E. Tymczyszyn Abstract Aims:, Although the practical importance of adding sugars before drying is well known, the mechanism of protection of bacteria by sugars is not clear. The response of the dehydrated micro-organisms to rehydration is analysed in terms of structural and functional changes, and correlated with their potentiality to grow in rich media. These aspects are related with the membrane integrity and the metabolic state of the rehydrated bacteria, measured by means of surface properties and permeability. To attain this objective, Lactobacillus delbrueckii subsp. bulgaricus was dehydrated in the presence and in the absence of sucrose and trehalose. The bacterial response upon rehydration was investigated by determining: (i) the lag time of the bacterial growing in rich media, (ii) the restoration of the surface properties and the cellular volume and (iii) the membrane integrity. Methods and Results:,Lactobacillus delbrueckii subsp. bulgaricus was grown in MRS at 37°C overnight [De Man et al. (1960)J Appl Bacteriol 23, 130] and then dehydrated for 10, 20 and 30 min at 70°C in a vacuum centrifuge. The lag time of micro-organisms was determined by optical density changes after rehydration. The surface properties were determined by measuring the zeta potential of the bacteria suspended in aqueous solution. The cellular volume recovery was measured, after stabilization in saline solution, by light scattering and by the haematocrit method [Alemohammad and Knowles (1974)J Gen Microbiol 82, 125]. Finally, the membrane integrity has been determined by using specific fluorescent probes [SYTO 9 and propidium iodide, (PI)] that bind differentially depending on the integrity of the bacterial membrane. The lag time of Lact. delbrueckii subsp bulgaricus, dehydrated by heat in the presence of sucrose or trehalose and after that rehydrated, was significantly shortened, when compared with that obtained for bacteria dried in the absence of sugars. In these conditions, trehalose and sucrose maintained the zeta potential and the cell volume close to the control (nondried) cells. However, the membrane integrity, measured with fluorescent probes, was maintained only when cells were dehydrated for 10 min in the presence of sugars. For larger times of dehydration, the membrane integrity was not preserved, even in the presence of sugars. Conclusions:, When the micro-organisms are dehydrated in the absence of protectants, the membrane damage occurs with a decrease in the absolute value of the zeta potential and a decrease in the cellular volume recovered after rehydration. In contrast, when the zeta potential and the cellular volume are restored after rehydration to that corresponding to nondried cells, the micro-organisms are able to recover and grow with a reduced lag time. This can only be achieved when the dehydration is carried out in the presence of sugars. At short dehydration times, the response is associated with the preservation of the membrane integrity. However, for longer times of dehydration the zeta potential and volume recovery occurs in the presence of sugars in spite of a severe damage at membrane level. In this condition, cells are also recovered. In conclusion, to predict the ability of growing after dehydration, other bacterial structural parameters besides membrane integrity, such as zeta potential and cellular volume, should be taken into account. Significance and Impact of the Study:, The correlation of the lag time with the surface and permeability properties is of practical importance because the correlation of these two parameters with cell viability, allow to determine the potential bacterial capacity to grow in a rich medium after the preservation procedure, without necessity of performing a kinetic curve of growth, which is certainly time-consuming. [source] Argemone oil induced cellular damage in the reproductive tissues of transgenic Drosophila melanogaster: Protective role of 70 kDa heat shock proteinJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 4 2003Indranil Mukhopadhyay Abstract We explored the reproductive toxicity of argemone oil and its principal alkaloid fraction in transgenic Drosophila melanogaster (hsp70-lacZ) Bg9. The toxicity of argemone oil has been attributed to two of its physiologically active benzophenanthridine alkaloids, sanguinarine and dihydrosanguinarine. Freshly eclosed first instar larvae of transgenic Drosophila melanogaster were transferred to different concentrations of argemone oil and its alkaloid fraction contaminated food. Virgin flies that eclosed from the contaminated food were pair-mated to look into the effect on reproduction. The study was further extended by investigating hsp70 expression and tissue damage in larval gonads, genital discs, and reproductive organs of adult fly. Our results showed that argemone oil was more cytotoxic than its principal alkaloid fraction. Moreover, it was the male fly that was more affected compared to its opposite number. The accessory glands of male reproductive system of the fly, which did not express hsp70, exhibited severe damage as evidenced by Trypan blue staining. This prompted us to explore the ultrastructural morphology of the gland, which showed acute signs of necrosis in both the cell types as evident by necrotic nuclei, higher vacuolization, and disorganized endoplasmic reticulum, decrease in the number of Golgi vesicles and disorganized, loosely packed filamentous structures in the lumen of the accessory gland, at the higher concentrations of the adulterant. The study showed the reproductive toxicity of argemone oil and its alkaloid fraction in transgenic Drosophila melanogaster and further confirmed the cytoprotective role of hsp70. © 2003 Wiley Periodicals, Inc. J Biochem Mol Toxicol 17:223,234, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.10082. [source] An ecological study of the relationship between two living fossils in Malawi: the Mulanje Tiger Moth (Callioratis grandis) and the Mulanje Cycad (Encephalartos gratus)AFRICAN JOURNAL OF ECOLOGY, Issue 2 2010Julian Bayliss Abstract The Mulanje tiger moth (Callioratis grandis) has recently been discovered feeding solely on the Mulanje Cycad, Encephalartos gratus. In its type locality Encephalartos gratus is severely threatened through habitat destruction and human population growth. As a result the first detailed demographic survey of Encephalartos gratus on Mount Mulanje was undertaken with particular emphasis on the relationship between E. gratus and Callioratis grandis. What is unusual about C. grandis is that the males exhibit lekking behaviour, for which aposematism may be a prerequisite. Cycads were surveyed in a systematic manner. Both the biotic and abiotic parameters were recorded from 532 wild Encephalartos gratus. Results showed the morphological range of measurements differed from that of previously published literature on this species. Results also showed that the incidence of Callioratis larval damage was related to the maturity of the wild cycads , moth damage was greater on more mature plants. Approximately 50% of surveyed cycads showed evidence of Callioratis moth damage, however, there was no apparent preference from the moth to select either male or female cycads as food plants for the larvae. In some cases there was severe damage to cycad fronds, but this did not seem to affect the production of reproductive cones or even the survival of individual cycads. Résumé On a découvert récemment que le papillon du Mulanje (Callioratis grandis) ne se nourrit que sur le cycadale Mulanje Encephalartos gratus. Dans son milieu type, Encephalartos gratus est gravement menacé dans la nature à cause de la destruction de l'habitat et de la croissance de la population humaine. Par conséquent, la première étude démographique détaillée d'Encephalartos gratus réalisée sur le mont Mulanje fut entreprise en insistant particulièrement sur la relation entre Encephalartos gratus et Callioratis grandis. Ce qui est inhabituel chez C. grandis, c'est que les mâles présentent un comportement territorial (lek). Les cycadales ont été systématiquement surveillées. On a enregistré les paramètres biotiques et abiotiques pour 532 Encephalartos gratus poussant dans la nature. Les résultats ont montré que l'amplitude des mesures morphologiques différait de ce que la littérature existante décrit sur cette espèce. Ils ont aussi montré que l'incidence des dommages causés par les larves de Callioratisétait liée à la maturité des cycadales sauvages , les dégâts causés par les papillons étaient plus graves sur les plants plus matures. Environ 50% des cycadales suivis montraient des traces de dommages causés par ce papillon, mais il n'y avait pas de preuve qui aurait pu montrer que le papillon sélectionnait des cycadales mâles ou femelles pour en nourrir ses larves. Dans certains cas, il y avait des dégâts sérieux dans les feuilles de cycadales; cependant, cela ne semblait pas affecter la production de cônes reproducteurs, pas plus que la survie des individus. [source] Cellular response to oxidative stress: Signaling for suicide and survival,JOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2002Jennifer L. Martindale Reactive oxygen species (ROS), whether produced endogenously as a consequence of normal cell functions or derived from external sources, pose a constant threat to cells living in an aerobic environment as they can result in severe damage to DNA, protein, and lipids. The importance of oxidative damage to the pathogenesis of many diseases as well as to degenerative processes of aging has becoming increasingly apparent over the past few years. Cells contain a number of antioxidant defenses to minimize fluctuations in ROS, but ROS generation often exceeds the cell's antioxidant capacity, resulting in a condition termed oxidative stress. Host survival depends upon the ability of cells and tissues to adapt to or resist the stress, and repair or remove damaged molecules or cells. Numerous stress response mechanisms have evolved for these purposes, and they are rapidly activated in response to oxidative insults. Some of the pathways are preferentially linked to enhanced survival, while others are more frequently associated with cell death. Still others have been implicated in both extremes depending on the particular circumstances. In this review, we discuss the various signaling pathways known to be activated in response to oxidative stress in mammalian cells, the mechanisms leading to their activation, and their roles in influencing cell survival. These pathways constitute important avenues for therapeutic interventions aimed at limiting oxidative damage or attenuating its sequelae. Published 2002 Wiley-Liss, Inc. [source] The effects of thermal effluent exposure on the gametogenesis of female fishJOURNAL OF FISH BIOLOGY, Issue 1 2000D. Luk High temperature in Swedish and Lithuanian thermal effluent areas influenced gametogenesis of female perch Perca fluviatilis, roach Rutilus rutilus and pike Esox lucius negatively, indicating reduced reproductive capacity. Oocyte atresia started during vitellogenesis in autumn, and was often followed by asynchronous egg cell development. Among other anomalies, multi-nucleus oocytes and hermaphroditism were observed. No significant impact was seen in silver bream Blicca bjoerkna. Ruffe Gymnocephalus cernuus reacted by a tendency to produce an additional mature oocyte generation during the spawning period. Ovaries in roach from coastal areas were often infected by a microsporidian parasite Pleistophora mirandellae, causing severe damage to the gonad. Parasites were also detected in pike, but neither in perch nor in lake populations of roach. Fish living in open coastal environments did not avoid impact by moving out of the heated areas. There seems to be a conflict in some temperate fish between temperature preference behaviour and safeguarding normal reproduction. [source] Increased incidence of saprophytic bacteria, coliforms and E. coli following severe flooding requires risk assessment for human health: results of the River Elbe flood in August 2002JOURNAL OF FLOOD RISK MANAGEMENT, Issue 1 2009B. Karrasch Abstract In August 2002, flooding in the Elbe valley caused severe damage of sewage treatment plants and networks. We investigated the impact of flooding on the bacteriological water quality (colony-forming units of saprophytic bacteria, coliform bacteria and Escherichia coli) compared with levels from previous and subsequent years. The flood introduced organic matter and elevated saprophytic bacteria levels, and a general increase of coliform bacteria. Markedly high loads of coliforms and E. coli were detected in the water column in areas where damage to sewage treatment plants was rife, exceeding the European Commission's Bathing Water Directive. The rapid disappearance from the water column may partly be caused by sedimentation creating deposits on pasture, farmland and in built-up areas, which could represent a health hazard. Future flood risk reduction should therefore be focused on the protection of sewage systems and hygienic monitoring of floodwater and flood sediments. [source] Performance of the potentially invasive Siberian moth Dendrolimus superans sibiricus on coniferous species in EuropeAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2009Natalia I. Kirichenko Abstract 1,The native range of the Siberian moth extends from the Pacific Ocean (Russian Far East, Japan and Northern Korea) across Siberia, Northern China and Mongolia to the Ural Mountains. At the beginning of the 21st Century, this species was documented west of the Ural Mountains in the Republic of Mari El, indicating range extension toward the west. 2,The Siberian moth has recently been suggested for regulation as a quarantine pest for European and Mediterranean Plant Protection Organization member countries. However, no specific report on European host plants for this pest has been published so far. 3,In the present study, larval host plant choice and performance was tested for the first time on coniferous tree species that are widely distributed and of commercial value in Europe. 4,Based on dual-choice tests on neonates and mortality, developmental duration and relative growth rates of the first- to sixth-instar larvae, we found European larch Larix decidua to be the most suitable host for the moth larvae, whereas European black pine Pinus nigra and Scots pine Pinus sylvestris were the poorest hosts. The remaining conifer species tested, European silver fir Abies alba, Nordmann fir Abies nordmanniana, and Norway spruce Picea abies, were intermediate host plants. Douglas-fir Pseudotsuga menziesii, originating from North America, was chosen by the larvae to the same extend as European larch, and was also highly suitable for larval development. 5,If the moth is introduced to European countries, it will become damaging in stands of European larch and Douglas-fir, mixed stands of fir and spruce; however, it will be less damaging in forests dominated by two-needle pines. 6,We predict that Dendrolimus superans sibiricus will be able to survive and develop on the main European coniferous tree species, including non-native coniferous tree species, resulting in severe damage to large areas of forests. [source] The role of RANKL and MMP-9 in the bone resorption caused by ameloblastomaJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 8 2010Yong Qian J Oral Pathol Med (2010) 39: 592,598 Background:, Ameloblastoma, a common odontogenic tumor located in jaws, generally leads to severe damage to patient's complexion and masticatory function. To expand in jaws, ameloblastoma must have a mechanism of resorbing the surrounding bone. Our objective was to explore the bone-resorption mechanism of ameloblastoma by observing the role of Receptor activator of nuclear factor kappa B ligand (RANKL) and matrix metalloproteinase-9 (MMP-9) in the bone-resorption process. Methods:, In the study, the expression of RANKL and MMP-9 in ameloblastoma was detected using immunohistochemistry (IHC) and RT-PCR. Then, co-culture system of ameloblastoma cells and bone marrow cells from neonatal rabbit was erected to observe the potential of ameloblastoma cells to induce osteoclastogenesis. Finally, the induced osteoclasts were used for in vitro bone-resorption assay. In the co-culture system and the bone-resorption assay, the selective inhibitor of RANKL and MMP-9, osteoprotegerin (OPG) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were, respectively, used for observing the role of RANKL and MMP-9. Results:, The expression of RANKL and MMP-9 in ameloblastoma was confirmed. Ameloblastoma cells were found to induce bone marrow cells from neonatal rabbit differentiate into osteoclasts with bone-resorption activity. In addition, OPG was found to, respectively, have markedly inhibitory effect on osteoclastogenesis (P < 0.01), and slightly inhibitory action on bone resorption (P < 0.05). Conclusions:, Ameloblastoma cells had the potential to induce osteoclastogenesis. Moreover, RANKL played an essential role in the in vitro osteoclast formation and bone resorption induced by ameloblastoma cells. [source] Identification of Three Strains of a Virus Associated with Cassava Plants Affected by Frogskin DiseaseJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2008L. A. Calvert Abstract Cassava Frogskin Disease (CFSD) can cause severe damage to cassava roots and is one of the most important diseases of cassava in Latin America. The principal objective of this study was to identify the causal agent of CFSD. Electron microscopy, viral purifications, double-stranded RNA (dsRNA) analysis, cloning, sequencing, rtPCR and hybridizations were carried out to characterize and associate a novel virus with the disease. Virus-like particles of 70 and 45 nm in diameter were found in affected cassava plants and partially purified preparations respectively. Nine species of dsRNA were associated with this disease and cDNA clones to six genomic segments were synthesized from the purified dsRNAs. The putative proteins predicted from the sequence of the cassava virus cDNA clones have similarity with the P1, P2, P3, P4, P5 and P10 proteins of Rice ragged stunt virus (RRSV). Phylogenic analysis confirmed that this virus is a member of the family Reoviridae and is most closed related to RRSV. Hybridization analyses of dsRNA identified S1, S2, S3, S4, S5 and S10 genomic segments in the CFSD-affected plants, but not in healthy controls. Additionally, 26 isolates were compared using a portion of the putative polymerase gene. The virus was detected in all 26 isolates, and they were classified into three distinct races. The association of this virus with CFSD was strengthened by the detection of this virus in diseased plants collected from different locations throughout Colombia. [source] Mechanisms of protection by melatonin against acetaminophen-induced liver injury in miceJOURNAL OF PINEAL RESEARCH, Issue 3 2006Tatsuya Matsura Abstract:, The present study was performed to determine whether melatonin protects mouse liver against severe damage induced by acetaminophen (APAP) administration and where melatonin primarily functions in the metabolic pathway of APAP to protect mouse liver against APAP-induced injury. Treatment of mice with melatonin (50 or 100 mg/kg, p.o.) 8 or 4 hr before APAP administration (750 mg/kg, p.o.) suppressed the increase in plasma alanine aminotransferase and aspartate aminotransferase activities in a dose- and a time-dependent manner. Melatonin treatment (100 mg/kg, p.o.) 4 hr before APAP administration remarkably inhibited centrilobular hepatic necrosis with inflammatory cell infiltration and increases in hepatic lipid peroxidation and myeloperoxidase activity, an index of tissue neutrophil infiltration, as well as release of nitric oxide and interleukin-6 into blood circulation at 9 hr after APAP administration. However, melatonin neither affected hepatic reduced glutathione (GSH) content nor spared hepatic GSH consumption by APAP treatment. Moreover, pretreatment with melatonin 4 hr before APAP administration did not influence the induction of hepatic heat shock protein 70 (HSP70) by APAP and melatonin alone did not induce HSP70 in mouse liver. These results indicate that exogenously administered melatonin exhibits a potent hepatoprotective effect against APAP-induced hepatic damage probably downstream of the activity of cytochrome P450 2E1, which works upstream of GSH conjugation in the pathway of APAP metabolism, via its anti-nitrosative and anti-inflammatory activities in addition to its antioxidant activity. [source] Equity Risk, Conversion Risk, and the Demand for InsuranceJOURNAL OF RISK AND INSURANCE, Issue 3 2003Rod Garratt Existing insurance theory fails when applied to real property because it does not account for variations in the economic environment. The article studies optimal property insurance in the presence of two sources of variation: equity risk and conversion risk. Equity risk is randomness of the value of a property. It tends to raise demand for conventional insurance. In contrast, conversion risk is randomness in the value the property would have if, after severe damage, it were converted to the highest-valued use. It is distinct from equity risk because the highest-valued use is typically not the current one. Under independent conversion risk, the optimum upper limit is a compromise among underlying conversion thresholds. Absent independence, the optimum can be quite different. Conversion risk can raise or lower the demand for property insurance. Insurance contracts that fail to address conversion tend to undermine the orderly disposition of obligations and reduce the gains from reallocation of risks through insurance. [source] A simple and practical method in treatment of ingrown nails: splinting by flexible tubeJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 10 2006S Nazari Abstract Background, The ingrown nail (or onychocryptosis) is a common problem that occurs mostly in the big toe and causes high amounts of morbidity in affected patients. Many therapeutic methods have been described, most of them leading to severe damage to the nail or to frequent relapses. The nail splinting technique is a successful, simple and non-invasive therapeutic method for treating ingrown nails. Objective, To determine efficacy of the plastic tube insertion technique in patients with ingrown toenail and its use as a standard treatment. Materials and Methods, We encountered 32 cases (age range 9,67 years) of ingrown toenails in this clinical trial. All of the patients were treated using the plastic nail tube insertion technique for 7 to 15 days. Patients were examined daily for the first 3 days of treatment and were evaluated 3 and 6 months after treatment. All patients were followed up by a single observer. Results, Recurrence was seen in only two patients after 6 months of treatment (6.25%). Conclusion, The low recurrence rate using the nail splinting technique in the treatment of ingrown toenail, as well as its simple application, shows that this treatment constitutes an effective, non-invasive method. It appears that this technique can substitute other more invasive surgical methods, particularly in the early stages of this disease. [source] Phrenic nerve diabetic neuropathy in rats: unmyelinated fibers morphometryJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2009Valéria Paula S. Fazan Abstract We have demonstrated that phrenic nerves' large myelinated fibers in streptozotocin (STZ)-induced diabetic rats show axonal atrophy, which is reversed by insulin treatment. However, studies on structural abnormalities of the small myelinated and the unmyelinated fibers in the STZ-model of neuropathy are limited. Also, structural changes in the endoneural vasculature are not clearly described in this model and require detailed study. We have undertaken morphometric studies of the phrenic nerve in insulin-treated and untreated STZ-diabetic rats and non-diabetic control animals over a 12-week period. The presence of neuropathy was assessed by means of transmission electron microscopy, and morphometry of the unmyelinated fibers was performed. The most striking finding was the morphological evidence of small myelinated fiber neuropathy due to the STZ injection, which was not protected or reversed by conventional insulin treatment. This neuropathy was clearly associated with severe damage of the endoneural vessels present on both STZ groups, besides the insulin treatment. The STZ-diabetes model is widely used to investigate experimental diabetic neuropathies, but few studies have performed a detailed assessment of either unmyelinated fibers or capillary morphology in this animal model. The present study adds useful information for further investigations on the ultrastructural basis of nerve function in diabetes. [source] Temporary hair removal by low fluence photoepilation: Histological study on biopsies and cultured human hair folliclesLASERS IN SURGERY AND MEDICINE, Issue 8 2008Guido F. Roosen MSc Abstract Background and Objectives We have recently shown that repeated low fluence photoepilation (LFP) with intense pulsed light (IPL) leads to effective hair removal, which is fully reversible. Contrary to permanent hair removal treatments, LFP does not induce severe damage to the hair follicle. The purpose of the current study is to investigate the impact of LFP on the structure and the physiology of the hair follicle. Study Design/Materials and Methods Single pulses of IPL with a fluence of 9 J/cm2 and duration of 15 milliseconds were applied to one lower leg of 12 female subjects, followed by taking a single biopsy per person, either immediately, or after 3 or 7 days. Additionally, we present a novel approach to examine the effects of LFP, in which ex vivo hairy human scalp skin was exposed to IPL pulses with the same parameters as above, followed by isolation and culturing of the hair follicles over several days. Samples were examined histologically and morphologically. Results The majority of the cultured follicles that had been exposed to LFP treatment showed a marked treatment effect. The melanin containing part of the hair follicle bulb was the target and a catagen-like transformation was observed demonstrating that hair formation had ceased. The other follicles that had been exposed to LFP showed a less strong or no response. The skin biopsies also revealed that the melanin-rich region of the hair follicle bulb matrix was targeted; other parts of the follicle and the skin remained unaffected. Catagen/telogen hair follicles were visible with unusual melanin clumping, indicating this cycle phase was induced by the IPL treatment. Conclusions Low fluence photoepilation targets the pigmented matrix area of the anagen hair follicle bulb, causing a highly localized but mild trauma that interrupts the hair cycle, induces a catagen-like state and eventually leads to temporary loss of the hair. Lesers Surg. Med. 40:520,528, 2008. © 2008 Wiley-Liss, Inc. [source] Microbial status in seawater and coastal sediments during pre- and post-tsunami periods in the Bay of Bengal, IndiaMARINE ECOLOGY, Issue 3 2006Subramani Ramesh Abstract Tsunami, the natural disaster, which occurred on December 26, 2004 in the Indian Ocean, caused severe damage to mankind in the coastal areas. Total loss of life and economic loss because of this disaster have been estimated by various agencies but its effect on microbial density has not been probed. With our previous results on microbial populations in four locations of the Chennai coast of the Bay of Bengal, India in the pre-tsunami period, the change in microbial populations was studied after the tsunami at regular intervals in the same locations. Coastal sediment and seawater samples were collected from four different locations after 5,10 h and thereafter at intervals of every 7 days up to 28 days post-tsunami. Bacteria, fungi and actinomycetes were isolated from the marine samples by serial dilution on respective media. Before the tsunami, the bacterial population was higher in seawater samples than the sediments, whereas fungi and actinomycetes were recorded only in the sediments. The microbial population remarkably increased 5,10 h post-tsunami in all the marine samples irrespective of the location. However, it slowly declined in the subsequent days and became similar to that of the population recorded before the tsunami. The population of gram-positive bacteria increased whereas the gram-negative bacterial population decreased after the tsunami. Further, populations of pathogenic bacteria such as coliform and vibrios did not increase after the tsunami. It has been observed that the increase in populations of bacteria and actinomycetes even after 28 days of tsunami may be due to the introduction of foreign microorganisms that developed the ability to survive in the extreme environment by exhibiting special characteristics such as pigmentation and production of exopolysaccharides. [source] Critical considerations for future action during the second commitment period: A small islands' perspectiveNATURAL RESOURCES FORUM, Issue 2 2007Leonard Nurse Abstract If the objective of the United Nations Framework Convention on Climate Change (UNFCCC) is to be achieved, Parties must commit themselves to meeting meaningful long-term targets that, based on current knowledge, would minimize the possibility of irreversible climate change. Current indications are that a global mean temperature rise in excess of 2,3 °C would enhance the risk of destabilizing the climate system as we know it, and possibly lead to catastrophic change such as a shutdown of the deep ocean circulation, and the disintegration of the West Arctic Ice Sheet. Observations have shown that for many small island developing States (SIDS), life-sustaining ecosystems such as coral reefs, already living near the limit of thermal tolerance, are highly climate-sensitive, and can suffer severe damage from exposure to sea temperatures as low as 1 °C above the seasonal maximum. Other natural systems (e.g., mangroves) are similarly susceptible to relatively low temperature increases, coupled with small increments of sea level rise. Economic and social sectors, including agriculture and human health, face similar challenges from the likely impacts of projected climate change. In light of known thresholds, this paper presents the view that SIDS should seek support for a temperature cap not exceeding 1.5,2.0 °C above the pre-industrial mean. It is argued that a less stringent post-Kyoto target would frustrate achievement of the UNFCCC objective. The view is expressed that all countries which emit significant amounts of greenhouse gases should commit to binding reduction targets in the second commitment period, but that targets for developing countries should be less stringent than those agreed for developed countries. Such an arrangement would be faithful to the principles of equity and would ensure that the right of Parties to attain developed country status would not be abrogated. [source] Urgent liver transplantation for Amanita phalloides poisoningPEDIATRIC TRANSPLANTATION, Issue 1 2008Baris Dogu Yildiz Abstract:,Amanita phalloides is a deadly wild mushroom causing severe damage in man ranging from diarrhea to organ dysfunction. If not treated, mortality is as high as 80%. Treatment includes supportive measures, inactivation of the toxin and if liver failure occurs liver transplantation. The indications for transplantation are debatable. [source] Development of insect-resistant transgenic rice with Cry1C*-free endospermPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 9 2009Rongjian Ye Abstract BACKGROUND: Yellow stem borer (Tryporyza incertulas Walker), striped stem borer (Chilo suppressalis Walker) and leaf folder (Cnaphalocrocis medinalis Guenec) are three lepidopteran pests that cause severe damage to rice in many areas of the world. In this study, novel insect-resistant transgenic rice was developed in which Bt protein expression was nearly absent in the endosperm. The resistant gene, cry1C*, driven by the rice rbcS promoter (small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase), was introduced into Zhonghua 11 (Oryza sativa L. ssp. japonica) by Agrobacterium -mediated transformation. RESULTS: A total of 83 independent transformants were obtained, 19 of which were characterised as single-copy foreign gene insertion. After preliminary screening of the T1 families of these 19 transformants in the field, six highly insect-resistant homozygous lines were selected. These six homozygous transgenic lines were field tested for resistance to leaf folders and stem borers, and for their agronomic performance. The Cry1C* protein levels in leaves and endosperm were measured by ELISA. Subsequently, the elite transgenic line RJ5 was selected; this line not only possessed high resistance to leaf folders and stem borers, normal agronomic performance, but also Cry1C* expression was only 2.6 ng g,1 in the endosperm. CONCLUSION: These results indicated that RJ5 has the potential for widespread utility in rice production. Copyright © 2009 Society of Chemical Industry [source] | ||||||||||||||||||||||||||||||||||||||||