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1.
Sci Total Environ ; 823: 154017, 2022 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-35305837

RESUMEN

Poisoning caused by ingestion of spent lead (Pb) ammunition in food items is a common cause of death of raptors. However, there has been no previous attempt to assess the impact of lead poisoning on populations of raptors throughout Europe or examine how this relates to the prevalence of hunting. We used measurements of lead concentration in the liver from over 3000 raptors of 22 species found dead or dying in the wild in 13 countries and a lead poisoning threshold of 20 ppm (dry weight) to assess the proportion of these in which lead poisoning caused or contributed to death. The prevalence of lead poisoning as a cause of death of raptors varied substantially among European countries and was positively correlated across countries with the reported number of hunters per unit area. Ten species had a non-zero proportion of individuals with concentrations exceeding the lead poisoning threshold ranging between 0.3% and 16.5%. The estimated annual conditional death rate from lead poisoning for these ten species averaged 0.44% (range 0.06-0.85%). Scavenging species feeding regularly on carcasses of game animals,tended to have a high annual probability of death from lead poisoning. So too did some predators which only sometimes scavenge, but prey on frequently hunted birds, such as gamebirds, waterfowl and pigeons, which may contain ingested or embedded lead shot. Small-bodied predators had a low annual probability of death from lead poisoning. Modelling indicated that European populations of adult raptors of the ten focal species averaged 6.0% smaller (range 0.2-14.4%) than they would be without the effects of lead poisoning. A given rate of lead poisoning mortality resulted in greater expected population reductions for species with high annual survival rate and late age at first breeding.


Asunto(s)
Intoxicación por Plomo , Rapaces , Animales , Aves , Europa (Continente)/epidemiología , Humanos , Plomo/análisis , Intoxicación por Plomo/epidemiología , Intoxicación por Plomo/veterinaria
2.
Chemosphere ; 190: 80-89, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28985539

RESUMEN

Veterinary medicines can be extremely damaging to the environment, as seen with the catastrophic declines in Gyps vulture in South Asia due to their secondary exposure to diclofenac in their primary food source. Not surprisingly, concern has been raised over other similar drugs. In this study, we evaluate the toxicity of carprofen to the Gyps vulture clade through plasma pharmacokinetics evaluations in Bos taurus cattle (their food source) and Gyps africanus (a validated model species); tissue residues in cattle; and the effect of carprofen as a secondary toxicant as both tissue-bound residue or pure drug at levels expected in cattle tissues. Carprofen residues were highest in cattle kidney (7.72 ± 2.38 mg/kg) and injection site muscle (289.05 ± 98.96 mg/kg of dimension of 5 × 5 × 5 cm). Vultures exposed to carprofen as residues in the kidney tissue or pure drug equivalents showed no toxic signs. When exposed to average injection site concentrations (64 mg/kg) one of two birds died with evidence of severe renal and liver damage. Toxicokinetic analysis revealed a prolonged drug half-life of 37.75 h in the dead bird as opposed to 13.99 ± 5.61 h from healthy birds dosed intravenously at 5 mg/kg. While carprofen may generally be harmless to Gyps vultures, its high levels at the injection site in treated cattle can result in lethal exposure in foraging vultures, due to relative small area of tissue it is found therein. We thus suggest that carprofen not be used in domesticated ungulates in areas where carcasses are accessible or provided to vultures at supplementary feeding sites.


Asunto(s)
Carbazoles/toxicidad , Falconiformes , Drogas Veterinarias/toxicidad , Animales , Antiinflamatorios no Esteroideos/farmacocinética , Antiinflamatorios no Esteroideos/toxicidad , Asia , Carbazoles/farmacocinética , Bovinos , Muerte , Diclofenaco/farmacocinética , Diclofenaco/toxicidad , Semivida , Riñón/efectos de los fármacos , Riñón/patología , Hígado/efectos de los fármacos , Hígado/patología , Toxicocinética , Drogas Veterinarias/farmacocinética
3.
Brain Struct Funct ; 221(4): 1911-25, 2016 05.
Artículo en Inglés | MEDLINE | ID: mdl-25721800

RESUMEN

The frontotemporal cortical network is associated with behaviours such as impulsivity and aggression. The health of the uncinate fasciculus (UF) that connects the orbitofrontal cortex (OFC) with the anterior temporal lobe (ATL) may be a crucial determinant of behavioural regulation. Behavioural changes can emerge after repeated concussion and thus we used MRI to examine the UF and connected gray matter as it relates to impulsivity and aggression in retired professional football players who had sustained multiple concussions. Behaviourally, athletes had faster reaction times and an increased error rate on a go/no-go task, and increased aggression and mania compared to controls. MRI revealed that the athletes had (1) cortical thinning of the ATL, (2) negative correlations of OFC thickness with aggression and task errors, indicative of impulsivity, (3) negative correlations of UF axial diffusivity with error rates and aggression, and (4) elevated resting-state functional connectivity between the ATL and OFC. Using machine learning, we found that UF diffusion imaging differentiates athletes from healthy controls with significant classifiers based on UF mean and radial diffusivity showing 79-84 % sensitivity and specificity, and 0.8 areas under the ROC curves. The spatial pattern of classifier weights revealed hot spots at the orbitofrontal and temporal ends of the UF. These data implicate the UF system in the pathological outcomes of repeated concussion as they relate to impulsive behaviour. Furthermore, a support vector machine has potential utility in the general assessment and diagnosis of brain abnormalities following concussion.


Asunto(s)
Conmoción Encefálica/patología , Conmoción Encefálica/fisiopatología , Lóbulo Frontal/patología , Lóbulo Frontal/fisiopatología , Conducta Impulsiva/fisiología , Lóbulo Temporal/patología , Lóbulo Temporal/fisiopatología , Adulto , Anciano , Agresión/fisiología , Atletas/psicología , Conmoción Encefálica/diagnóstico , Imagen de Difusión Tensora , Femenino , Fútbol Americano/lesiones , Sustancia Gris/patología , Sustancia Gris/fisiopatología , Humanos , Aprendizaje Automático , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Vías Nerviosas/patología , Vías Nerviosas/fisiopatología , Pruebas Neuropsicológicas , Corteza Prefrontal/patología , Corteza Prefrontal/fisiopatología , Sensibilidad y Especificidad
4.
J Dairy Sci ; 98(3): 2005-12, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25597971

RESUMEN

The fertility of dairy cattle in New Zealand is well below industry targets, and the current New Zealand fertility breeding value (BV) could potentially be improved using additional information and traits. Data from 169 herds were analyzed to determine the benefits of using alternative phenotypic measures in the calculation of the fertility BV. The heritability of calving season day (CSD; calving season day as an integer day of the year) and the probability of an animal calving within 42 d of the planned start of calving (CR42) increased modestly (from 0.0206 to 0.0213 and 0.0087 to 0.0092, respectively) after accounting for the use of intravaginal progesterone-releasing devices for treatment of anestrous cows (anestrum treatment) and induced calvings. Incidence of either anestrum treatment or calving induction as a single binomial trait (AT/IND) had a heritability of 0.0223 and showed moderate genetic correlation with the probability of an animal being mated within 21 d of the planned start of mating (PM21; -0.4473), but much higher with CSD (0.8445). The use of pregnancy diagnosis data allowed fertility information that would otherwise be discarded to be included in analyses; when used to assign a prolonged CSD and a value of 0 for CR42 to animals that failed to calve, it increased the heritabilities of both of these traits (to 0.0278 and 0.0114, respectively). Because CSD was found to be more than twice as heritable as its binary counterpart, it shows potential to replace CR42 as the calving trait used in the fertility BV. Postpartum anestrous interval (PPAI), derived using incomplete premating estrous recording in some herds, had a heritability of 0.0813 and hence has potential as a trait to be included in genetic improvement programs but would require more rigorous recording of estrous during the premating period to be an effective trait. Based on selection index theory, the modifications made to current selection criteria using novel fertility traits increased the accuracy of prediction of fertility merit by more than 12%. Because of the increasing economic importance of fertility traits, and low heritabilities requiring large numbers of recorded daughters to get accurate fertility BV predictions on sires, data recorded on farm will become increasingly important in the genetic improvement of fertility.


Asunto(s)
Cruzamiento/métodos , Bovinos/fisiología , Fertilidad/genética , Pruebas Genéticas , Inseminación Artificial/veterinaria , Animales , Bovinos/genética , Industria Lechera , Femenino , Inseminación Artificial/estadística & datos numéricos , Modelos Genéticos , Nueva Zelanda
6.
Science ; 342(6160): 871-4, 2013 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-24233726

RESUMEN

The geographic and temporal origins of the domestic dog remain controversial, as genetic data suggest a domestication process in East Asia beginning 15,000 years ago, whereas the oldest doglike fossils are found in Europe and Siberia and date to >30,000 years ago. We analyzed the mitochondrial genomes of 18 prehistoric canids from Eurasia and the New World, along with a comprehensive panel of modern dogs and wolves. The mitochondrial genomes of all modern dogs are phylogenetically most closely related to either ancient or modern canids of Europe. Molecular dating suggests an onset of domestication there 18,800 to 32,100 years ago. These findings imply that domestic dogs are the culmination of a process that initiated with European hunter-gatherers and the canids with whom they interacted.


Asunto(s)
Animales Domésticos/genética , Perros/genética , Genoma Mitocondrial/genética , Animales , Secuencia de Bases , Cruzamiento , Europa (Continente) , Datos de Secuencia Molecular , Filogenia , Lobos/genética
7.
J Parasitol ; 99(4): 634-8, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23347228

RESUMEN

In this study we describe 2 new species of coccidia (Apicomplexa: Eimeriidae) parasites isolated from the feces of corncrake (Crex crex) (Gruiformes: Rallidae), bred in captivity in the U.K. Oocysts of Eimeria crecis n. sp. were approximately spherical and measured 15.3 µm (13-18) × 14.3 (12-16), providing an oocyst shape index of 1.1. A micropyle and oocyst residuum were absent, but a polar granule was present. Oocysts of Eimeria nenei n. sp. were ellipsoidal and measured 23.6 (21-26) × 18.1 (17-20), providing an oocyst shape index of 1.3. A micropyle and polar granule were present. Surveying free-living, wild adult corncrakes in Scotland (U.K.) demonstrated both parasite species to be widespread. These are the first species described to infect the corncrake, and they are distinct from those previously found to infect members of the closely related crane family (Gruiformes: Gruidae). Partial amplification and sequencing of the 18S rRNA gene and internal transcribed spacer 2 indicated a close relationship between the 2 proposed new species as a group distinct from the Eimeria species known to infect cranes. These newly identified parasite species have been associated with enteric disease in corncrakes being prepared for reproduction in captivity and reintroduction into England (U.K.).


Asunto(s)
Enfermedades de las Aves/parasitología , Coccidiosis/veterinaria , Eimeria/clasificación , Animales , Enfermedades de las Aves/epidemiología , Aves , Coccidiosis/epidemiología , Coccidiosis/parasitología , ADN Protozoario/química , ADN Protozoario/aislamiento & purificación , Eimeria/genética , Eimeria/ultraestructura , Heces/parasitología , Oocistos/clasificación , Oocistos/ultraestructura , Filogenia , Prevalencia , ARN Ribosómico 18S/genética , Reino Unido/epidemiología
8.
Food Chem Toxicol ; 50(11): 4180-90, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22939931

RESUMEN

We estimate potential risks to human health in the UK from dietary exposure to lead from wild gamebirds killed by shooting. The main source of exposure to lead in Europe is now dietary. We used data on lead concentrations in UK gamebirds, from which gunshot had been removed following cooking to simulate human exposure to lead. We used UK food consumption and lead concentration data to evaluate the number of gamebird meals consumed weekly that would be expected, based upon published studies, to result in changes, over and above those resulting from exposure to lead in the base diet, in intelligence quotient (IQ), Systolic Blood Pressure and chronic kidney disease (CKD) considered in a recent opinion of the European Food Safety Authority (EFSA) to be significant at a population level and also in SAT test scores and in rates of spontaneous abortion. We found the consumption of <1 meal of game a week may be associated with a one point reduction in IQ in children and 1.2-6.5 gamebird meals per week may be associated with the other effects. These results should help to inform the development of appropriate responses to the risks from ingesting lead from ammunition in game in the UK and European Union (EU).


Asunto(s)
Dieta , Plomo/toxicidad , Productos de la Carne , Aborto Espontáneo/epidemiología , Aborto Espontáneo/etiología , Adulto , Animales , Aves , Niño , Preescolar , Contaminación de Alimentos , Inocuidad de los Alimentos , Humanos , Pruebas de Inteligencia , Plomo/administración & dosificación , Plomo/sangre , Productos de la Carne/efectos adversos , Insuficiencia Renal Crónica/epidemiología , Insuficiencia Renal Crónica/etiología , Factores de Riesgo , Reino Unido
9.
Heredity (Edinb) ; 107(3): 205-14, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21304545

RESUMEN

The identification of the causative genetic variants in quantitative trait loci (QTL) influencing phenotypic traits is challenging, especially in crosses between outbred strains. We have previously identified several QTL influencing tameness and aggression in a cross between two lines of wild-derived, outbred rats (Rattus norvegicus) selected for their behavior towards humans. Here, we use targeted sequence capture and massively parallel sequencing of all genes in the strongest QTL in the founder animals of the cross. We identify many novel sequence variants, several of which are potentially functionally relevant. The QTL contains several regions where either the tame or the aggressive founders contain no sequence variation, and two regions where alternative haplotypes are fixed between the founders. A re-analysis of the QTL signal showed that the causative site is likely to be fixed among the tame founder animals, but that several causative alleles may segregate among the aggressive founder animals. Using a formal test for the detection of positive selection, we find 10 putative positively selected regions, some of which are close to genes known to influence behavior. Together, these results show that the QTL is probably not caused by a single selected site, but may instead represent the joint effects of several sites that were targets of polygenic selection.


Asunto(s)
Agresión , Sitios de Carácter Cuantitativo , Selección Genética , Alelos , Animales , Secuencia de Bases , Femenino , Variación Genética , Genoma , Secuenciación de Nucleótidos de Alto Rendimiento , Masculino , Análisis de Secuencia por Matrices de Oligonucleótidos , Fenotipo , Polimorfismo de Nucleótido Simple , Ratas , Análisis de Secuencia de ADN
10.
Reprod Domest Anim ; 44(3): 406-10, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18954390

RESUMEN

The aim of this study was to evaluate the viability in the effect of open pulled straw (OPS) vitrification procedure of sheep embryos after direct transference. Embryos were produced in vivo and cryopreserved in slow freezing or OPS vitrification. The survival rates of cryopreserved embryos were compared to non-frozen standard pattern. In a first set of experiments, embryos at morula and blastocyst stages were dived in ethylene glycol (1.5 M) and frozen in an automatic freezer. After being thawed, they were directly or indirectly transferred to ewes recipient. A second group of embryos were drawn into OPS and plunged into liquid nitrogen after being exposed at room temperature for 1 min and 45 s in 10% EG plus 10% dimethyl sulphoxide (DMSO), then again for 30 s in 20% EG + 20% DMSO + 0.5 M sucrose. After being warmed, embryos were also directly transferred using a French mini straw as the catheter for the transplantation process or after in vitro dilution of cryoprotectants (two-step-process). No significant difference was observed among fresh, frozen or vitrified embryos on pregnancy rate (50.0%, 38.6% and 55.8%). However, when we evaluated only the direct transference, the pregnancy rate of OPS vitrified embryos was higher than that of frozen embryos (57.1% vs 34.8%) (p = 0.07). In addition, vitrified morulae had a higher pregnancy rate than the one with frozen embryos (64.0% vs 38.9%) (p = 0.07). Finally, our results indicate that OPS vitrification technique in association with direct transference improves the viability of sheep embryos with potential applications to field conditions.


Asunto(s)
Blastocisto/fisiología , Criopreservación/veterinaria , Transferencia de Embrión/veterinaria , Mórula/fisiología , Ovinos/embriología , Animales , Criopreservación/instrumentación , Criopreservación/métodos , Transferencia de Embrión/métodos , Femenino , Calor , Embarazo , Índice de Embarazo
11.
Proc Natl Acad Sci U S A ; 105(28): 9495-500, 2008 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-18621701

RESUMEN

Global efforts to conserve biodiversity have the potential to deliver economic benefits to people (i.e., "ecosystem services"). However, regions for which conservation benefits both biodiversity and ecosystem services cannot be identified unless ecosystem services can be quantified and valued and their areas of production mapped. Here we review the theory, data, and analyses needed to produce such maps and find that data availability allows us to quantify imperfect global proxies for only four ecosystem services. Using this incomplete set as an illustration, we compare ecosystem service maps with the global distributions of conventional targets for biodiversity conservation. Our preliminary results show that regions selected to maximize biodiversity provide no more ecosystem services than regions chosen randomly. Furthermore, spatial concordance among different services, and between ecosystem services and established conservation priorities, varies widely. Despite this lack of general concordance, "win-win" areas-regions important for both ecosystem services and biodiversity-can be usefully identified, both among ecoregions and at finer scales within them. An ambitious interdisciplinary research effort is needed to move beyond these preliminary and illustrative analyses to fully assess synergies and trade-offs in conserving biodiversity and ecosystem services.


Asunto(s)
Carbono , Conservación de los Recursos Naturales , Ecosistema , Mapas como Asunto , Biodiversidad , Geografía
12.
Chemosphere ; 72(1): 45-52, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18374966

RESUMEN

Recent discovery of low concentrations of bromacil in drinking water prompted the State of Hawaii to examine the leaching behavior of bromacil in pineapple fields. This study is a follow up to earlier work on bromacil concentrations in soil profiles in a pineapple field in central Oahu, Hawaii. Soil samples were collected for bromacil analysis at different times prior to and after application from a pineapple field that was previously surveyed by other research workers. The leaching pattern of bromacil was further investigated at two different application rates (2.25 and 1.8 kg ha(-1)). The concentration of bromacil in the topsoil about 100 days after bromacil application (1.8 kg ha(-1)) was substantially higher in 2002 compared to 1999. The distribution profiles were generally consistent with the one presented in the previous study. Residual bromacil was present in the entire sampled zone (3m deep) about 18 months after the previous bromacil application. Over a period of 9 months, there was substantial dissipation of bromacil residue present in the topsoil. The residual concentration of bromacil in the area that received the reduced application rate (1.8 kg ha(-1)) were lower than those receiving the current application rate (2.25 kg ha(-1)) and the depth of penetration of the bromacil front was shallower at the reduced application rate. Because of the common practice of placing plastic mulch around the base of the pineapple plants to retain volatile nematicides, the applied bromacil was found to be concentrated in the areas between the plastic mulch, transported by runoff from the plastic. The study results encourage the use of less than the label led rate of application of bromacil for pineapple fields.


Asunto(s)
Agricultura , Ananas , Bromouracilo/análogos & derivados , Herbicidas/química , Contaminantes del Suelo/química , Bromouracilo/química , Hawaii
13.
Ann Hum Genet ; 72(Pt 1): 99-110, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18184145

RESUMEN

The primary aim of genetic association and linkage studies is to identify genetic variants that contribute to phenotypic variation within human populations. Since the overwhelming majority of human genetic variation is found within populations, these methods are expected to be effective and can likely be extrapolated from one human population to another. However, they may lack power in detecting the genetic variants that contribute to phenotypes that differ greatly between human populations. Phenotypes that show large differences between populations are expected to be associated with genomic regions exhibiting large allele frequency differences between populations. Thus, from genome-wide polymorphism data genomic regions with large allele frequency differences between populations can be identified, and evaluated as candidates for large between-population phenotypic differences. Here we use allele frequency data from approximately 1.5 million SNPs from three human populations, and present an algorithm that identifies genomic regions containing SNPs with extreme Fst. We demonstrate that our candidate regions have reduced heterozygosity in Europeans and Chinese relative to African-Americans, and are likely enriched with genes that have experienced positive natural selection. We identify genes that are likely responsible for phenotypes known to differ dramatically between human populations and present several candidates worthy of future investigation. Our list of high Fst genomic regions is a first step in identifying the genetic variants that contribute to large phenotypic differences between populations, many of which have likely experienced positive natural selection. Our approach based on between population differences can compliment traditional within population linkage and association studies to uncover novel genotype-phenotype relationships.


Asunto(s)
Alelos , Frecuencia de los Genes , Genética de Población , Polimorfismo de Nucleótido Simple , Selección Genética , Negro o Afroamericano , Algoritmos , Pueblo Asiatico , Consanguinidad , Ligamiento Genético , Variación Genética , Haplotipos , Heterocigoto , Humanos , Modelos Genéticos , Grupos de Población , Población Blanca
14.
Environ Int ; 33(6): 759-65, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17433834

RESUMEN

Gyps vulture populations across the Indian subcontinent are declining rapidly and evidence indicates that veterinary use of the non-steroidal anti-inflammatory drug (NSAID) diclofenac is the major cause. Exposure of vultures to diclofenac is likely to arise from the consumption of livestock carcasses that have been treated shortly before death, however, detailed information regarding the prevalence and residual levels of diclofenac in carcasses available to vultures in India remains unreported. Here, we present data on diclofenac residues in 1848 liver samples taken from carcasses of dead livestock sampled at 67 sites in 12 states within India, between May 2004 and July 2005. Diclofenac residues were detected in carcasses in all states except Orisa, where only one site was sampled. The overall prevalence of detectable diclofenac (>10 microg kg(-1)) across all states was 10.1% and varied significantly among states, with up to 22.3% prevalence determined in Bihar. The geometric mean concentration of diclofenac found in samples in which the drug was detected was 352 microg kg(-1). The prevalence of carcasses containing diclofenac is similar to that previously proposed to be required to have caused the observed Gyps vulture declines in India. On the 11th of May 2006, the Drug Controller General (India) ordered the withdrawal of all licenses granted for the manufacture of diclofenac for veterinary use within India. However, if Gyps vultures are to be protected, potentially substantial existing stocks now need to be quickly and effectively removed from the Indian veterinary market.


Asunto(s)
Animales Domésticos/metabolismo , Antiinflamatorios no Esteroideos/metabolismo , Diclofenaco/metabolismo , Falconiformes/metabolismo , Animales , Antiinflamatorios no Esteroideos/toxicidad , Bovinos , Diclofenaco/toxicidad , Conducta Alimentaria/efectos de los fármacos , Femenino , India , Masculino
15.
Environ Pollut ; 147(1): 60-5, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17069941

RESUMEN

Gyps vultures across India are declining rapidly and the NSAID diclofenac has been shown to be the major cause. Vultures scavenge livestock carcasses that have been treated with diclofenac within the days preceding death. We present data on diclofenac disposition in Indian cow and goat, and field data on the prevalence of diclofenac in carcases in the environment. In the disposition experiment, animals were treated with a single intramuscular injection of diclofenac at 1000 microg kg-1 bw. In cow, diclofenac was detectable in liver, kidney and intestine up to 71 h post-treatment; in plasma, half-life was 12.2 h. In goat, tissue residues were undetectable after 26 h. Prevalence of diclofenac in liver from 36 dead livestock collected in the field was 13.9%. Data suggest that diclofenac residues in Indian cow and goat are short-lived, but diclofenac prevalence in carcasses available to vultures may still be very high.


Asunto(s)
Antiinflamatorios no Esteroideos/farmacocinética , Diclofenaco/farmacocinética , Residuos de Medicamentos/análisis , Falconiformes/fisiología , Contaminación de Alimentos/análisis , Carne/análisis , Animales , Bovinos , Cadena Alimentaria , Cabras , Semivida , India , Intestinos/química , Riñón/química , Hígado/química , Dinámica Poblacional
16.
Proc Natl Acad Sci U S A ; 103(37): 13578-84, 2006 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-16938852

RESUMEN

Whereas evolutionary inferences derived from present-day DNA sequences are by necessity indirect, ancient DNA sequences provide a direct view of past genetic variants. However, base lesions that accumulate in DNA over time may cause nucleotide misincorporations when ancient DNA sequences are replicated. By repeated amplifications of mitochondrial DNA sequences from a large number of ancient wolf remains, we show that C/G-to-T/A transitions are the predominant type of such misincorporations. Using a massively parallel sequencing method that allows large numbers of single DNA strands to be sequenced, we show that modifications of C, as well as to a lesser extent of G, residues cause such misincorporations. Experiments where oligonucleotides containing modified bases are used as templates in amplification reactions suggest that both of these types of misincorporations can be caused by deamination of the template bases. New DNA sequencing methods in conjunction with knowledge of misincorporation processes have now, in principle, opened the way for the determination of complete genomes from organisms that became extinct during and after the last glaciation.


Asunto(s)
Artefactos , Citosina/química , Guanina/química , Paleontología/métodos , Análisis de Secuencia de ADN/métodos , Animales , Secuencia de Bases , Evolución Molecular , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Moldes Genéticos , Lobos/genética
17.
Brain Cogn ; 60(2): 199-201, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16646119

RESUMEN

The status of neurorehabilitation for traumatic brain injury (TBI) is under active debate because of a dearth of research findings demonstrating effectiveness. This may be due, in part, to limitations in our understanding of basic mechanisms of cognitive and motor recovery,including those that might impede recovery. In this regard, we examined whether overall recovery following TBI might be undermined by competition between cognitive and motor functions for finite neural resources during recovery. In this preliminary study, 21 moderately and severely impaired patients were administered cognitive and motor assessments at 1, 4, and 12 months post-TBI, and recovery of cognitive and motor functions was measured using regression residuals. Negative correlations between recovery of cognitive versus motor functions were used as the index of competition. We found suggestive evidence that there may indeed be a trade-off between the recovery of cognitive and motor functions after TBI. Implications for rehabilitation are discussed.


Asunto(s)
Lesiones Encefálicas/rehabilitación , Trastornos del Conocimiento/rehabilitación , Destreza Motora , Modalidades de Fisioterapia , Recuperación de la Función , Adulto , Lesiones Encefálicas/complicaciones , Cognición , Trastornos del Conocimiento/etiología , Estudios de Seguimiento , Humanos , Análisis de Regresión , Índice de Severidad de la Enfermedad , Resultado del Tratamiento
18.
Brain Cogn ; 60(2): 201-3, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16646120

RESUMEN

We examined preliminarily whether intensive mental activity can transiently enhance higher cognitive functioning in healthy adults. Ten healthy participants performed intensive mental activity for 2 weeks. The intervention entailed daily memorization of multiple prose passages and performance of demanding, speeded mental arithmetic.Neuropsychological testing was conducted before and after the intervention, using alternate forms. (The intervention and neuropsychological tests were different.) Findings in the intervention group were compared to those of a convenience control sample who had performed a near-identical neuropsychological assessment and follow-up in a different study, but who did not perform the intervention. The purpose was to rule out practice effects as the cause of any observed improvement in the intervention group. The intervention group showed improvement on six/eight measures. The non-intervention group showed improvement on only two. Results suggest cognitive capacity can be enhanced in healthy individuals after a period of intensive cognitive stimulation. Implications for rehabilitation are discussed.


Asunto(s)
Lesiones Encefálicas/rehabilitación , Trastornos del Conocimiento/rehabilitación , Cognición/fisiología , Ambiente , Procesos Mentales/fisiología , Solución de Problemas/fisiología , Adulto , Lesiones Encefálicas/complicaciones , Trastornos del Conocimiento/etiología , Terapia Cognitivo-Conductual , Humanos , Pruebas Neuropsicológicas , Valores de Referencia , Resultado del Tratamiento , Aprendizaje Verbal/fisiología
19.
Philos Trans R Soc Lond B Biol Sci ; 360(1454): 243-54, 2005 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-15814343

RESUMEN

The need to monitor trends in biodiversity raises many technical issues. What are the features of a good biodiversity index? How should trends in abundance of individual species be estimated? How should composite indices, possibly spanning very diverse taxa, be formed? At what spatial scale should composite indices be applied? How might change-points--points at which the underlying trend changes--be identified? We address some of the technical issues underlying composite indices, including survey design, weighting of the constituent indices, identification of change-points and estimation of spatially varying time trends. We suggest some criteria that biodiversity measures for use in monitoring surveys should satisfy, and we discuss the problems of implementing rigorous methods. We illustrate the properties of different composite indices using UK farmland bird data. We conclude that no single index can capture all aspects of biodiversity change, but that a modified Shannon index and the geometric mean of relative abundance have useful properties.


Asunto(s)
Biodiversidad , Conservación de los Recursos Naturales/métodos , Conservación de los Recursos Naturales/tendencias , Proyectos de Investigación , Animales , Aves/fisiología , Interpretación Estadística de Datos , Densidad de Población , Especificidad de la Especie , Reino Unido
20.
J Thorac Cardiovasc Surg ; 121(4): 743-9, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11279417

RESUMEN

OBJECTIVE: Neuropsychologic impairment is a common complication of coronary bypass surgery. Cerebral microemboli during cardiopulmonary bypass are the principal cause of cognitive deficits after coronary bypass grafting. We have previously demonstrated that the majority of cerebral emboli occur during perfusionist interventions (ie, during the injection of air into the venous side of the cardiopulmonary bypass circuit). The purpose of this study was to determine whether an increase in perfusionist interventions is associated with an increased risk of postoperative cognitive impairment. METHODS: Patients undergoing elective coronary artery bypass grafting (n = 83) underwent a battery of neuropsychologic tests preoperatively and 3 months postoperatively. Patients were divided into 2 groups according to the median value of perfusionist interventions during cardiopulmonary bypass. Group 1 patients (n = 42) had fewer than 10 perfusionist interventions, and group 2 patients (n = 41) had 10 or more interventions. RESULTS: The 2 groups of patients were similar for all preoperative, intraoperative, and postoperative variables, with the exception of longer cardiopulmonary bypass times in group 2 patients (P <.001). Group 2 patients had lower mean scores on 9 of 10 neuropsychologic tests, with 3 (Rey Auditory Verbal Learning, Digit Span, and Visual Span) being statistically significant. Group 2 patients had worse cognitive test scores, even when controlling for increased bypass times. Group 2 patients had a nonsignificant trend toward an increased prevalence of neuropsychologic impairment 3 months postoperatively. CONCLUSIONS: Introduction of air into the cardiopulmonary bypass circuit by perfusionists, resulting in cerebral microembolization, may contribute to postoperative cognitive impairment.


Asunto(s)
Puente Cardiopulmonar/efectos adversos , Trastornos del Conocimiento/etiología , Puente de Arteria Coronaria/psicología , Embolia Intracraneal/psicología , Puente Cardiopulmonar/psicología , Trastornos del Conocimiento/diagnóstico por imagen , Trastornos del Conocimiento/epidemiología , Trastornos del Conocimiento/psicología , Puente de Arteria Coronaria/efectos adversos , Enfermedad Coronaria/cirugía , Femenino , Humanos , Embolia Intracraneal/complicaciones , Embolia Intracraneal/diagnóstico por imagen , Embolia Intracraneal/epidemiología , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Prevalencia , Estudios Prospectivos , Ultrasonografía Doppler Transcraneal
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