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1.
J Environ Manage ; 295: 113061, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34348430

RESUMO

Common carp (Cyprinus carpio) are an invasive species of the rivers and waterways of south-eastern Australia, implicated in the serious decline of many native fish species. Over the past 50 years a variety of control options have been explored, all of which to date have proved either ineffective or cost prohibitive. Most recently the use of cyprinid herpesvirus 3 (CyHV-3) has been proposed as a biocontrol agent, but to assess the risks and benefits of this, as well as to develop a strategy for the release of the virus, a knowledge of the fundamental processes driving carp distribution and abundance is required. To this end, we developed a novel process-based modelling framework that integrates expert opinion with spatio-temporal datasets via the construction of a Bayesian Network. The resulting weekly networks thus enabled an estimate of the habitat suitability for carp across a range of hydrological habitats in south-eastern Australia, covering five diverse catchment areas encompassing in total a drainage area of 132,129 km2 over a period of 17-27 years. This showed that while suitability for adult and subadult carp was medium-high across most habitats throughout the period, nevertheless the majority of habitats were poorly suited for the recruitment of larvae and young-of-year (YOY). Instead, high population abundance was confirmed to depend on a small number of recruitment hotspots which occur in years of favourable inundation. Quantification of the underlying ecological drivers of carp abundance thus makes possible detailed planning by focusing on critical weaknesses in the population biology of carp. More specifically, it permits the rational planning for population reduction using the biocontrol agent, CyHV-3, targeting areas where the total population density is above a "damage threshold" of approximately 100 kg/ha.


Assuntos
Carpas , Doenças dos Peixes , Infecções por Herpesviridae , Animais , Austrália , Teorema de Bayes , Herpesviridae , Espécies Introduzidas
2.
Transbound Emerg Dis ; 64(6): 2023-2033, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28160424

RESUMO

Highly pathogenic avian influenza H5N1 has resulted in large losses to the Indonesian poultry sector. Evidence suggests that live bird markets (LBMs) play an important role in the epidemiology of the disease. Knowledge of the frequency and type of contact between the various poultry market players should allow animal health authorities to develop a better understanding of factors influencing virus transmission between Indonesian villages. A questionnaire-based cross-sectional survey was conducted in 17 LBMs on the neighbouring Indonesian islands of Bali and Lombok to investigate the movement patterns of poultry to and from markets. Using social network analyses, a network of contacts was created for each island from a total of 413 live poultry traders and 134 customers. Individual nodes with high degree and/or betweenness were identified in each network. The Lombok network was more dense and connected than the Bali network indicating that disease transmission would be more efficient in the Lombok network. Our findings indicate that whilst live poultry are typically transported over relatively short distances of approximately 10 km, it is not uncommon for traders and customers to travel in excess of 100 km to buy or sell poultry, which may facilitate the spread of disease over a large geographical area. This study highlights the different roles markets play in poultry movement networks and their potential for disease dissemination. The identification of highly influential market nodes allows authorities to target HPAI surveillance activities to locations where disease is more likely to be present, which is crucial in low-resource settings.


Assuntos
Comércio , Virus da Influenza A Subtipo H5N1/fisiologia , Influenza Aviária/epidemiologia , Doenças das Aves Domésticas/epidemiologia , Animais , Estudos Transversais , Humanos , Indonésia/epidemiologia , Virus da Influenza A Subtipo H5N1/patogenicidade , Influenza Aviária/transmissão , Influenza Aviária/virologia , Aves Domésticas , Doenças das Aves Domésticas/transmissão , Doenças das Aves Domésticas/virologia , Inquéritos e Questionários
3.
Zoonoses Public Health ; 64(1): 53-62, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27357237

RESUMO

Highly pathogenic avian influenza (HPAI) subtype H5N1 remains an enzootic disease of village chickens in Indonesia, posing ongoing risk at the animal-human interface. Previous modelling showed that the fast natural turnover of chicken populations might undermine herd immunity after vaccination, although actual details of how this effect applies to Indonesia's village chicken population have not been determined. We explored the turnover effect in Indonesia's scavenging and mixed populations of village chickens using an extended Leslie matrix model parameterized with data collected from village chicken flocks in Java region, Indonesia. Population dynamics were simulated for 208 weeks; the turnover effect was simulated for 16 weeks after vaccination in two 'best case' scenarios, where the whole population (scenario 1), or birds aged over 14 days (scenario 2), were vaccinated. We found that the scavenging and mixed populations have different productive traits. When steady-state dynamics are reached, both populations are dominated by females (54.5%), and 'growers' and 'chicks' represent the most abundant age stages with 39% and 38% in the scavenging, and 60% and 25% in the mixed population, respectively. Simulations showed that the population turnover might reduce the herd immunity below the critical threshold that prevents the re-emergence of HPAI H5N1 4-8 weeks (scavenging) and 6-9 weeks (mixed population) after vaccination in scenario 1, and 2-6 weeks (scavenging) and 4-7 weeks (mixed population) after vaccination in scenario 2. In conclusion, we found that Indonesia's village chicken population does not have a unique underlying population dynamic and therefore, different turnover effects on herd immunity may be expected after vaccination; nonetheless, our simulations carried out in best case scenarios highlight the limitations of current vaccine technologies to control HPAI H5N1. This suggests that the improvements and complementary strategies are necessary and must be explored.


Assuntos
Criação de Animais Domésticos , Galinhas , Virus da Influenza A Subtipo H5N1/patogenicidade , Vacinas contra Influenza/imunologia , Influenza Aviária/prevenção & controle , Animais , Simulação por Computador , Feminino , Humanos , Indonésia/epidemiologia , Influenza Aviária/epidemiologia , Influenza Aviária/virologia , Masculino , Modelos Biológicos , Dinâmica Populacional , Vacinação
4.
Vet J ; 216: 8-17, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27687920

RESUMO

Field surveillance of British cattle using the single intradermal comparative cervical tuberculin (SICCT) test shows a higher incidence rate of bovine tuberculosis (bTB) in dairy compared to beef herds, but a lower probability of post-mortem examination confirmed (PMC) Mycobacterium bovis infection in dairy herds. A cross-sectional study was conducted to compare animal level differences in bTB detection between dairy and non-dairy cattle in Great Britain. During the period from 2002 to 2005, 200 (41% dairy) reactors in the SICCT test (standard interpretation) were randomly selected, and 200 in-contact cattle (43% dairy) were purposively selected from bTB-infected herds. Interferon (IFN)-γ responses in blood to bovine and avian purified protein derivative (PPD), and early secretory antigen target 6 kDa and culture filtrate protein 10 (ESAT-6/CFP10), were measured. The post-mortem examination included gross pathological examination, mycobacterial culture and histopathology. The proportions of cattle positive to ESAT6/CFP10 were 26% (95% confidence interval, CI, 15-39%) in dairy reactors and 62% (95% CI 51-72%) in non-dairy reactors (P <0.001). PMC risk was 34% (95% CI 24-45%) in dairy reactors and 69% (95% CI 60-78%) in non-dairy reactors (P <0.001). The odds ratio for PMC risk in dairy reactors compared to non-dairy reactors, after controlling for bTB prevalence, herd size and SICCT test response, was 0.27 (95% CI 0.14-0.53; P <0.001). In surveillance data, adjusted animal level PMC risks were lower for dairy reactors than for beef reactors aged >2 years (P <0.001).


Assuntos
Testes Intradérmicos/veterinária , Mycobacterium bovis/isolamento & purificação , Teste Tuberculínico/veterinária , Tuberculose Bovina/diagnóstico , Animais , Autopsia , Bovinos , Estudos Transversais , Indústria de Laticínios , Testes Diagnósticos de Rotina/veterinária , Feminino , Incidência , Masculino , Mycobacterium bovis/imunologia , Fatores de Risco , Tuberculose Bovina/epidemiologia , Tuberculose Bovina/imunologia , Reino Unido/epidemiologia
5.
PLoS One ; 11(6): e0155252, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27304985

RESUMO

Hendra virus (HeV) is an important emergent virus in Australia known to infect horses and humans in certain regions of the east coast. Whilst pteropid bats ("flying foxes") are considered the natural reservoir of HeV, which of the four mainland species is the principal reservoir has been a source of ongoing debate, particularly as shared roosting is common. To help resolve this, we sampled a colony consisting of just one of these species, the grey-headed flying fox, (Pteropus poliocephalus), at the southernmost extent of its range. Using the pooled urine sampling technique at approximately weekly intervals over a two year period, we determined the prevalence of HeV and related paramyxoviruses using a novel multiplex (Luminex) platform. Whilst all the pooled urine samples were negative for HeV nucleic acid, we successfully identified four other paramyxoviruses, including Cedar virus; a henipavirus closely related to HeV. Collection of serum from individually caught bats from the colony showed that antibodies to HeV, as estimated by a serological Luminex assay, were present in between 14.6% and 44.5% of animals. The wide range of the estimate reflects uncertainties in interpreting intermediate results. Interpreting the study in the context of HeV studies from states to the north, we add support for an arising consensus that it is the black flying fox and not the grey-headed flying fox that is the principal source of HeV in spillover events to horses.


Assuntos
Quirópteros/virologia , Vírus Hendra/fisiologia , Infecções por Henipavirus/virologia , Doenças dos Cavalos/virologia , Cavalos/virologia , Animais , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/urina , Austrália/epidemiologia , Reservatórios de Doenças/virologia , Geografia , Vírus Hendra/imunologia , Infecções por Henipavirus/epidemiologia , Infecções por Henipavirus/transmissão , Interações Hospedeiro-Patógeno , Humanos , Infecções por Paramyxoviridae/epidemiologia , Infecções por Paramyxoviridae/transmissão , Infecções por Paramyxoviridae/virologia , Paramyxovirinae/imunologia , Paramyxovirinae/fisiologia , Prevalência , Estações do Ano , Fatores de Tempo , Zoonoses/virologia
6.
Prev Vet Med ; 110(3-4): 312-22, 2013 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-23642857

RESUMO

Novel arboviruses, including new serotypes of bluetongue virus, are isolated intermittently from cattle and insects in northern Australia. These viruses are thought to be introduced via windborne dispersal of Culicoides from neighbouring land masses to the north. We used the HYSPLIT particle dispersal model to simulate the spatio-temporal patterns of Culicoides dispersal into northern Australia from nine putative source sites across Indonesia, Timor-Leste and Papua New Guinea. Simulated dispersal was found to be possible from each site, with the islands of Timor and Sumba highlighted as the likely principal sources and February the predominant month of dispersal. The results of this study define the likely spatial extent of the source and arrival regions, the relative frequency of dispersal from the putative sources and the temporal nature of seasonal winds from source sites into arrival regions. Importantly, the methodology and results may be applicable to other insect and pathogen incursions into northern Australia.


Assuntos
Distribuição Animal , Ceratopogonidae/fisiologia , Insetos Vetores/fisiologia , Modelos Biológicos , Animais , Austrália , Bluetongue/virologia , Bovinos , Doenças dos Bovinos/virologia , Indonésia , Papua Nova Guiné , Estações do Ano , Ovinos/virologia , Timor-Leste
7.
Med Vet Entomol ; 26(3): 334-40, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22211884

RESUMO

The introduction of novel bluetongue serotypes and genotypes into northern Australia is considered possible via the long-distance windborne dispersal of Culicoides (Diptera: Ceratopogonidae) vectors from Southeast Asia. Initial findings from simulation modelling of potential dispersal over a 15-year period revealed that the greatest risk for incursion of windborne Culicoides from the island of Timor into northern Australia occurs during December-March. The regions at greatest risk for incursion include the top end of the Northern Territory and the Kimberley region in Western Australia, but there is potential for more widespread dispersal into northern Australia based on Timor as the putative source. The establishment of a more pathogenic strain of the virus, or of a novel Culicoides vector introduced by such inter-continental dispersal events, could dramatically alter Australia's current bluetongue disease status.


Assuntos
Migração Animal , Ceratopogonidae/fisiologia , Insetos Vetores/fisiologia , Animais , Austrália , Bluetongue/virologia , Bovinos , Doenças dos Bovinos/virologia , Indonésia , Modelos Biológicos , Risco , Estações do Ano , Ovinos/virologia , Vento
8.
Prev Vet Med ; 87(3-4): 311-26, 2008 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-18599138

RESUMO

Bovine tuberculosis (bTB) is a continuing problem in British herds. Micro-nutrients are important for the maintenance of well-functioning immune system. The aim of this study was to determine whether the selenium, copper and vitamin B12 status of cattle was associated with Mycobacterium bovis (M. bovis) infection. Between 2002 and 2005, 200 cattle (43% dairy, mean age 4.6 years), reactors according to the standard interpretation of the tuberculin test, and 200 in-contacts (41% dairy, mean age 4.4 years) non-reactors, which had been in contact with cattle with bTB, were selected from herds in England and Wales. Levels of the seleno enzyme glutathione peroxidase (GSHPx), copper and vitamin B12 were measured in blood. Confirmation of bTB infection was made by bacteriological culture and histopathology following a detailed postmortem. Levels of selenium and copper were also measured in a random sample of 63 livers. bTB was confirmed by culture/histology in 23/200 (11.5%) of in-contacts and 110/200 (55%) of reactors. In blood drawn at recruitment, GSHPx was lower in cattle with confirmed bTB compared to other cattle (geometric means 59.7 u/mL versus 78.9 u/mL red blood cells (RBC), p<0.01). Vitamin B12 was similar (geometric means 161.5 pmol/L versus 165.5 pmol/L, p=0.62) and copper was similar (geometric means 14.4 micromol/L versus 14.1 micromol/L, p=0.55). In logistic regression models including all micro-nutrients simultaneously and controlling for age, sex, animal production class, herd size, number of reactors, postmortem laboratory and seasonal trends, lower levels of GSHPx (adjusted OR 0.42, 95% CI 0.21-0.81 per 100 u/mL RBC, p=0.01) and higher levels of copper (adjusted OR 1.69, 95% CI 1.21-2.36 per 5 micromol/L, p<0.01) were associated with an increased risk of confirmed bTB but there was no association with vitamin B12. There was evidence for a stronger association between confirmed bTB and GSHPx in in-contacts (adjusted OR 0.21, 95% CI 0.06-0.79 per 100 u/mL RBC) compared to reactors (adjusted OR 0.50, 95% CI 0.21-1.23 per 100 u/mL RBC) (p=0.08 for interaction). Lower liver copper was associated with a higher risk of confirmed bTB (adjusted OR 0.15, 95% CI 0.02-1.0 per 5,000 micromol/kgdry mass, p=0.05) but there was no association between liver selenium and bTB. Trace micro-nutrient status may affect susceptibility to M. bovis infection in cattle. Further studies are needed.


Assuntos
Ração Animal/análise , Suscetibilidade a Doenças/veterinária , Oligoelementos , Tuberculose Bovina/metabolismo , Animais , Bovinos , Estudos de Coortes , Cobre/sangue , Cobre/química , Estudos Transversais , Feminino , Fígado/química , Modelos Logísticos , Masculino , Selênio/sangue , Selênio/química , Oligoelementos/química , Oligoelementos/farmacologia , Tuberculose Bovina/prevenção & controle
10.
Vet J ; 176(3): 354-60, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17728162

RESUMO

The aim of this study was to obtain a contemporary data set of pathology in tuberculin reactor and in-contact cattle in England and Wales. Four hundred animals (200 reactors and 200 in-contacts) from 242 farms located in 14 counties in Western England and Wales were examined. The mean number of lymph nodes (LNs) with tuberculosis (TB)-like lesions per TB-confirmed animal was 1.7 in reactors and 1.5 in in-contact animals. Tuberculous lesions in both reactor and in-contact animals were most commonly observed in the LNs of the thorax, followed by the head and abdomen, particularly the mediastinal, retropharyngeal and tracheobronchial LNs. Twenty-five reactors had macroscopic lesions in the palatine tonsils. Among TB-confirmed cattle, 27% of reactors and 9% of in-contact animals had gross TB-like lesions in the lungs, particularly in the caudal lobes. Gross lesions that were not TB-confirmed were parasitic granulomas (45%), bacterial or mycotic club-forming pyogranulomas (27%) and bacterial abscesses (23%). Diagnostic sensitivity was maximised when bacteriology and histopathology were used concurrently. Stage IV granulomas, alone or in combination with other stages, constituted 63% of lesions, while 16% of lesions were stage I/II granulomas. Caseous necrosis and calcification were common features of the granulomas encountered in natural Mycobacterium bovis infections, even with pathology limited to a small number of sites. Granulomas often covered large areas of histological sections and typically contained only small numbers of acid fast bacilli.


Assuntos
Granuloma/veterinária , Mycobacterium bovis/patogenicidade , Tuberculose Bovina/patologia , Animais , Bovinos , Inglaterra/epidemiologia , Feminino , Granuloma/epidemiologia , Granuloma/patologia , Pulmão/microbiologia , Pulmão/patologia , Linfonodos/microbiologia , Linfonodos/patologia , Masculino , Mycobacterium bovis/isolamento & purificação , Especificidade de Órgãos , Tonsila Palatina/microbiologia , Tonsila Palatina/patologia , Tuberculose Bovina/epidemiologia , País de Gales/epidemiologia
11.
Exp Gerontol ; 41(5): 474-81, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16626901

RESUMO

A convenient way to study processes of aging in distinct human tissues consists of a molecular analysis of cells from the tissue in question, that were explanted and grown in vitro until they reach senescence. Using human umbilical vein endothelial cells (HUVEC), we have established an in vitro senescence model for human endothelial cells. A major hallmark of HUVEC in vitro senescence is the increased frequency of apoptotic cell death, which occurs as a determining feature of HUVEC senescence. Senescent endothelial cells are also found in vivo in atherosclerotic lesions, suggesting that the presence of such cells may contribute to the development of vascular pathology. To elucidate mechanisms underlying endothelial cell senescence and age-associated apoptosis, gene expression analyses were carried out. In these experiments, we observed the up-regulation of genes coding for extracellular proteins in senescent HUVEC. In particular, a significant upregulation of interleukin-8, VEGI, and the IGF-binding proteins 3 and 5 was observed. Upregulation of these genes was confirmed by both RT-PCR and Western blot. In the case of interleukin-8, a roughly 50-fold upregulation of the protein was also found in cellular supernatants. The extracellular proteins encoded by these genes are well known for their ability to modulate the apoptotic response of human cells, and in the case of interleukin-8, clear links to the establishment of atherosclerotic lesions have been defined. The results described here support a new model, where changes in the secretome of human endothelial cells contribute to vascular aging and vascular pathology.


Assuntos
Senescência Celular/fisiologia , Células Endoteliais/fisiologia , Endotélio Vascular/citologia , Biossíntese de Proteínas/fisiologia , Apoptose , Western Blotting/métodos , Células Cultivadas , Células Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Humanos , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/biossíntese , Proteínas de Ligação a Fator de Crescimento Semelhante a Insulina/genética , Interleucina-8/biossíntese , Interleucina-8/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/biossíntese , Membro 15 da Superfamília de Ligantes de Fatores de Necrose Tumoral/genética , Veias Umbilicais/citologia , Veias Umbilicais/metabolismo , Regulação para Cima/fisiologia
12.
Exp Gerontol ; 41(1): 103-9, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16309877

RESUMO

Alterations in mitochondrial function are believed to play a major role in aging processes in many species, including fungi and animals, and increased oxidative stress is considered a major consequence of altered mitochondrial function. In support of this theory, a lot of correlative evidence has been collected, suggesting that changes in mitochondrial DNA accumulate with age in certain tissues. Furthermore, genetic experiments from lower eukaryotic model organisms, indicate a strong correlative link between increased resistance to oxidative stress and an extended lifespan; in addition, limited experimental evidence suggests that the inhibition of mitochondrial function by selected pharmacologically active compounds can extend lifespan in certain species. However, changes in mitochondrial function may affect aging in a different way in various tissues, and a clear statement about the role of mitochondrial deterioration during physiological aging is missing for most if not all species. At this point, respirometric analyses of mitochondrial function provide a tool to study age-associated changes in mitochondrial respiratory chain function and mitochondrial ATP production within living cells and isolated mitochondria. In the recent years, new instruments have been developed, which allow for an unprecedented high-resolution respirometry, which enables us to determine many parameters of mitochondrial function in routine assays using small samples of biological material. It is conceivable that this technology will become an important tool for all those, who are interested in experimentally addressing the mitochondrial theory of aging. In this article, we provide a synopsis of traditional respirometry and the advances of modern high-resolution respirometry, and discuss how future applications of this technology to recently established experimental models in aging research may provide exciting new insights into the role of mitochondria in the aging process.


Assuntos
Envelhecimento/metabolismo , Mitocôndrias/metabolismo , Consumo de Oxigênio/fisiologia , Envelhecimento/genética , Envelhecimento/fisiologia , Células Cultivadas , DNA Mitocondrial/genética , Eletrônica Médica , Endotélio Vascular/citologia , Endotélio Vascular/metabolismo , Humanos , Mitocôndrias/fisiologia , Estresse Oxidativo/fisiologia
13.
Prev Vet Med ; 71(3-4): 157-72, 2005 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-16188333

RESUMO

Four classes of Bayesian hierarchical models were evaluated using an historical dataset from an abattoir survey for fasciolosis conducted in Victoria, Australia. The purpose of this analysis was to identify areas of high prevalence and to explain these in terms of environmental covariates. The simplest of the Bayesian models, with a single random effect, validated the use of smoothed maps for cartographic display when the sample sizes vary. The model was then extended to partition the random effect into spatially structured and unstructured components, thus allowing for spatial autocorrelation. Rainfall, irrigation, temperature-adjusted rainfall and a remotely sensed surrogate for rainfall, the normalised difference vegetation index (NDVI), were then introduced into the models as explanatory variables. The variable that best explained the observed distribution was irrigation. Associations between prevalence and both rainfall and NDVI that were significant in fixed effects models were shown to be due to spatial confounding. Nevertheless, provided they are used cautiously, confounded variables may be valid predictors for the prevalence of disease.


Assuntos
Matadouros/estatística & dados numéricos , Teorema de Bayes , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/prevenção & controle , Fasciolíase/veterinária , Animais , Bovinos , Doenças dos Bovinos/etiologia , Fasciolíase/epidemiologia , Fasciolíase/prevenção & controle , Inquéritos e Questionários , Vitória/epidemiologia
14.
Rev Sci Tech ; 23(3): 873-84, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15861882

RESUMO

Web-enabled databases developed in the late 1990s to help organise large web sites and allow data capture via browser-based forms. By enabling users outside a closed network access to a central database, they permit greater flexibility than traditional 'client-server' systems. Accordingly, web-enabled databases introduce a new tool for epidemiologists, permitting direct data capture at source and thus avoiding many of the delays and errors arising from paper forms and manual data entry. In addition, real-time data collection permits sophisticated decision support and reporting, and thus improved project co-ordination and participation. Nevertheless, the technology is complex and the development of a web-application requires an attention to information technology project management equal to that of the scientific trial or investigation. The potential and problems of web database applications are illustrated by a bespoke system ('PathMan') developed by the Veterinary Laboratories Agency of the United Kingdom Department for Environment, Food and Rural Affairs to manage a large multi-site study investigating the pathogenesis of bovine tuberculosis in England and Wales.


Assuntos
Doenças dos Animais/epidemiologia , Doenças dos Animais/prevenção & controle , Bases de Dados Factuais/estatística & dados numéricos , Sistemas de Informação/organização & administração , Internet , Bem-Estar do Animal , Animais , Coleta de Dados , Estudos Epidemiológicos , Humanos , Sistemas de Informação/normas
15.
Prev Vet Med ; 56(1): 51-62, 2002 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-12419599

RESUMO

The commonest way of geo-referencing farms as single points is using the location of the farmhouse as either read off a map or approximated by its postcode. While these two methods may be adequate for small farms, they are unlikely to be satisfactory for large ones, or alternatively when they are comprised of several discrete units or holdings. In order to investigate the best representation of the total farm polygon(s) by a single point, we undertook a study using nearly 500 actual farm boundaries in the county of Cornwall, England. For each farm, the farm boundaries were digitised, and its area and centroid determined using ArcView 3.2. A variety of point geo-referencing systems were tested to find the best single point location for a farm, as judged by the proportion of farm area captured. Whilst the centroid was found to capture the largest area, the main farm building was judged to be the best geo-referencing method for practical purposes. In contrast, the various systems of geo-coding using the farm postal address performed relatively poorly. Where there are separate parcels of land managed together in a single parish, they may be identified as a single unit, but if there are separate parcels in different parishes they should be identified as separate units.The implications of these results for Great Britain's national animal health information system (VETNET) are discussed.


Assuntos
Agricultura , Sistemas de Informação Geográfica , Sistemas de Informação , Medicina Veterinária/estatística & dados numéricos , Doenças dos Animais/epidemiologia , Animais , Inglaterra
16.
Exp Gerontol ; 37(1): 41-55, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11738146

RESUMO

When mortal human cells reach their finite lifespan, they enter an irreversible G1 growth arrest status referred to as senescence. Growth suppression of senescent cells can be explained by the accumulation of several growth-suppressive proteins, acting on mitogenic signal transduction and cell cycle regulation, respectively. We show here that the cdk inhibitor p27(KIP1), which is involved in several forms of G1 checkpoint control, accumulates in senescent cells. Whereas, the rate of p27 synthesis is reduced, accumulation of p27 is accompanied by an increase of the metabolic stability in senescent cells. p27 is a substrate for ubiquitin-mediated proteolysis, and its stabilization in senescent cells correlates with a deregulation of the p27-specific E3 ubiquitin ligase referred to as the SCF complex. Whereas, the Skp1 component of the SCF complex is overexpressed in senescent fibroblasts, the abundance of the F-box protein Skp2 is strongly reduced. In contrast to our findings with p27, the synthesis of the cell cycle regulators p21 and cyclin D1 is increased in senescent cells; however, both proteins are also highly unstable in these cells.


Assuntos
Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Senescência Celular/fisiologia , Quinases Ciclina-Dependentes/antagonistas & inibidores , Expressão Gênica , Proteínas Supressoras de Tumor/metabolismo , Células Cultivadas , Ciclina D1/genética , Ciclina D1/metabolismo , Inibidor de Quinase Dependente de Ciclina p21 , Inibidor de Quinase Dependente de Ciclina p27 , Ciclinas/genética , Ciclinas/metabolismo , Fibroblastos/citologia , Fibroblastos/metabolismo , Humanos , Proteínas Quinases Associadas a Fase S , Proteínas Supressoras de Tumor/genética
17.
Oncogene ; 20(47): 6891-8, 2001 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-11687968

RESUMO

The metabolism of tumor cells (tumor metabolome) is characterized by a high concentration of glycolytic enzymes including pyruvate kinase isoenzyme type M2 (M2-PK), a high glutaminolytic capacity, high fructose 1,6-bisphosphate (FBP) levels and a low (ATP+GTP):(CTP+UTP) ratio. The sequence of events required for the establishment of the tumor metabolome is presently unknown. In non-transformed rat kidney (NRK) cells we observed a high glutaminolytic flux rate and a low (ATP+GTP):(CTP+UTP) ratio, whereas FBP levels and M2-PK activity are still extremely low. After stable expression of oncogenic ras in NRK cells a strong upregulation of FBP levels and of M2-PK activity was observed. Elevated FBP levels induce a tetramerization of M2-PK and its migration into the glycolytic enzyme complex. AMP levels increase whereas UTP and CTP levels strongly decrease. Thus, ras expression completes the glycolytic part of tumor metabolism leading to the inhibition of nucleic acid synthesis and cell proliferation. The HPV-16 E7 oncoprotein, which cooperates with ras in cell transformation, directly binds to M2-PK, induces its dimerization and restores nucleic acid synthesis as well as cell proliferation. Apparently, the combination of the different metabolic effects of ras and E7 constructs the perfect tumor metabolome as generally found in tumor cells.


Assuntos
Transformação Celular Neoplásica , Neoplasias/etiologia , Neoplasias/metabolismo , Proteína Oncogênica p21(ras)/fisiologia , Proteínas Oncogênicas Virais/farmacologia , Adenilato Quinase/metabolismo , Animais , Aspartato Aminotransferases/metabolismo , Linhagem Celular , Células Cultivadas , Glutamina/metabolismo , Glicólise , Rim/citologia , Modelos Biológicos , Nucleotídeos/metabolismo , Proteína Oncogênica p21(ras)/genética , Proteínas E7 de Papillomavirus , Piruvato Quinase/metabolismo , Ratos , Serina/metabolismo , Transfecção
18.
Exp Gerontol ; 36(8): 1327-47, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11602208

RESUMO

Human ageing is characterized by a progressive loss of physiological functions, increased tissue damage and defects in various tissue renewal systems. Age-related decreases of the cellular replicative capacity can be reproduced by in vitro assays of cellular ageing. When diploid human fibroblasts reach their finite lifespan, they enter an irreversible G1 growth arrest status referred to as replicative senescence. While deregulation of programmed cell death (apoptosis) is a key feature of age-related pathology in several tissues, this is not reflected in the standard in vitro senescence model of human fibroblasts, and the role of apoptosis during cellular ageing remains unclear. We have analyzed replicative senescence of human umbilical vein endothelial cells (HUVEC) in vitro and found that senescent HUVEC also arrest in the G1 phase of the cell cycle but, unlike fibroblasts, accumulate with a 4N DNA content, indicative of polyploidization. In contrast to human fibroblasts, senescent endothelial cells display a considerable increase in spontaneous apoptosis. The data imply that age-dependent apoptosis is a regular feature of human endothelial cells and suggest cell type specific differences in human ageing.


Assuntos
Senescência Celular/genética , Senescência Celular/fisiologia , Endotélio Vascular/citologia , Apoptose , Divisão Celular , Células Cultivadas , Ciclina A/metabolismo , Quinases Ciclina-Dependentes/antagonistas & inibidores , DNA/genética , DNA/metabolismo , Inibidores Enzimáticos/metabolismo , Fibroblastos/citologia , Fase G1 , Humanos , Técnicas In Vitro , Modelos Biológicos , Poliploidia
19.
FEBS Lett ; 499(1-2): 101-6, 2001 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-11418121

RESUMO

To analyze mechanisms of senescence-associated gene expression, we have investigated histone deacetylases (HDACs) in human fibroblasts undergoing replicative senescence. We found that the overall acetylation pattern of histones does not vary detectably with replicative senescence. By Northern blot and Western blot, we found a significant decrease in the abundance of HDAC-1 in senescent cells. Biochemical analysis of deacetylase activities in extracts from old and young cells revealed a striking difference. While by anion exchange chromatography we found a single peak of activity in extracts from young cells, which coincided with the elution of both HDAC-1 and HDAC-2, in senescent cells a second peak of activity was found. This second peak of activity is associated with HDAC-2 but does not contain HDAC-1. These results suggest that HDAC-2 is present in at least two distinct forms, one of which is specific for senescent cells. Further biochemical characterization of the enzyme activity revealed that addition of nicotinamide adenine dinucleotide (NAD) did not detectably influence the activity of any fraction, suggesting that NAD is not an essential co-factor for the analyzed HDACs from diploid human fibroblasts.


Assuntos
Senescência Celular , Regulação Enzimológica da Expressão Gênica , Histona Desacetilases/metabolismo , Proteínas Repressoras , Western Blotting , Extratos Celulares , Células Cultivadas , Senescência Celular/genética , Cromatografia por Troca Iônica , Fibroblastos/citologia , Fibroblastos/enzimologia , Fibroblastos/metabolismo , Histona Desacetilase 1 , Histona Desacetilase 2 , Histona Desacetilases/genética , Histona Desacetilases/isolamento & purificação , Histonas/química , Histonas/metabolismo , Humanos , NAD/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
20.
Biochem J ; 356(Pt 1): 247-56, 2001 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-11336658

RESUMO

Proliferating and tumour cells express the glycolytic isoenzyme, pyruvate kinase type M2 (M2-PK), which occurs in a highly active tetrameric form and in a dimeric form with low affinity for phosphoenolpyruvate. The switch between the two forms regulates glycolytic phosphometabolite pools and the interaction between glycolysis and glutaminolysis. In the present study, we show the effects of oncoprotein E7 of the human papilloma virus (HPV)-16 (E7)-transformation on two NIH 3T3 cell strains with different metabolic characteristics. E7-transformation of the high glycolytic NIH 3T3 cell strain led to a shift of M2-PK to the dimeric form and, in consequence, to a decrease in the cellular pyruvate kinase mass-action ratio, the glycolytic flux rate and the (ATP+GTP)/(UTP+CTP) ratio, as well as to an increase in fructose 1,6-bisphosphate (FBP) levels, glutamine consumption and cell proliferation. The low glycolytic NIH 3T3 cell strain is characterized by high pyruvate and glutamine consumption rates and by an intrinsically large amount of the dimeric form of M2-PK, which is correlated with high FBP levels, a low (ATP+GTP)/(CTP+UTP) ratio and a high proliferation rate. E7-transformation of this cell strain led to an alteration in the glycolytic-enzyme complex that correlates with an increase in pyruvate and glutamine consumption and a slight increase in the flow of glucose to lactate. The association of phosphoglyceromutase within the glycolytic-enzyme complex led to an increase of glucose and serine consumption and a disruption of the linkage between glucose consumption and glutaminolysis. In both NIH 3T3 cell lines, transformation increased glutaminolysis and the positive correlation between alanine and lactate production.


Assuntos
Transformação Celular Viral/fisiologia , Glutamina/metabolismo , Glicólise , Proteínas Oncogênicas Virais , Papillomaviridae , Piruvato Quinase/metabolismo , Células 3T3 , Animais , Isoenzimas/metabolismo , Lactatos/metabolismo , Camundongos , Modelos Biológicos , Nucleotídeos , Proteínas E7 de Papillomavirus , Conformação Proteica , Piruvato Quinase/química , Serina/metabolismo
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