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1.
Nature ; 593(7860): 548-552, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33882562

RESUMO

Global peatlands store more carbon than is naturally present in the atmosphere1,2. However, many peatlands are under pressure from drainage-based agriculture, plantation development and fire, with the equivalent of around 3 per cent of all anthropogenic greenhouse gases emitted from drained peatland3-5. Efforts to curb such emissions are intensifying through the conservation of undrained peatlands and re-wetting of drained systems6. Here we report eddy covariance data for carbon dioxide from 16 locations and static chamber measurements for methane from 41 locations in the UK and Ireland. We combine these with published data from sites across all major peatland biomes. We find that the mean annual effective water table depth (WTDe; that is, the average depth of the aerated peat layer) overrides all other ecosystem- and management-related controls on greenhouse gas fluxes. We estimate that every 10 centimetres of reduction in WTDe could reduce the net warming impact of CO2 and CH4 emissions (100-year global warming potentials) by the equivalent of at least 3 tonnes of CO2 per hectare per year, until WTDe is less than 30 centimetres. Raising water levels further would continue to have a net cooling effect until WTDe is within 10 centimetres of the surface. Our results suggest that greenhouse gas emissions from peatlands drained for agriculture could be greatly reduced without necessarily halting their productive use. Halving WTDe in all drained agricultural peatlands, for example, could reduce emissions by the equivalent of over 1 per cent of global anthropogenic emissions.

2.
Prostaglandins Other Lipid Mediat ; 152: 106499, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33035691

RESUMO

Prostaglandin E2 (PGE2) is found throughout the gastrointestinal tract in a diverse variety of functions and roles. The recent discovery of four PGE2 receptor subtypes in intestinal muscle layers as well as in the enteric plexus has led to much interest in the study of their roles in gut motility. Gut dysmotility has been implicated in functional disease processes including irritable bowel syndrome (IBS) and slow transit constipation, and lubiprostone, a PGE2 derivative, has recently been licensed to treat both conditions. The diversity of actions of PGE2 in the intestinal tract is attributed to its differing effects on its downstream receptor types, as well as their varied distribution in the gut, in both health and disease. This review aims to identify the role and distribution of PGE2 receptors in the intestinal tract, and aims to elucidate their distinct role in gut motor function, with a specific focus on functional intestinal pathologies.


Assuntos
Motilidade Gastrointestinal , Terapia de Alvo Molecular , Receptores de Prostaglandina E Subtipo EP2 , Humanos
3.
Nature ; 481(7382): 480-3, 2012 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-22281596

RESUMO

The standard model for the origin of galactic magnetic fields is through the amplification of seed fields via dynamo or turbulent processes to the level consistent with present observations. Although other mechanisms may also operate, currents from misaligned pressure and temperature gradients (the Biermann battery process) inevitably accompany the formation of galaxies in the absence of a primordial field. Driven by geometrical asymmetries in shocks associated with the collapse of protogalactic structures, the Biermann battery is believed to generate tiny seed fields to a level of about 10(-21) gauss (refs 7, 8). With the advent of high-power laser systems in the past two decades, a new area of research has opened in which, using simple scaling relations, astrophysical environments can effectively be reproduced in the laboratory. Here we report the results of an experiment that produced seed magnetic fields by the Biermann battery effect. We show that these results can be scaled to the intergalactic medium, where turbulence, acting on timescales of around 700 million years, can amplify the seed fields sufficiently to affect galaxy evolution.

4.
Br J Dermatol ; 177(1): 117-124, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28150889

RESUMO

BACKGROUND: Expression of P2X7 , an ATP-gated calcium channel, increases cancer cell proliferation and invasiveness. A variant of P2X7 (termed nfP2X7 ), in which a normally hidden epitope (E200) is exposed for antibody binding, is observed in a variety of different cancers. OBJECTIVES: To investigate the safety, tolerability and pharmacokinetics and assess indicative efficacy of a novel antibody ointment as a therapeutic for basal cell carcinoma (BCC). METHODS: An open-label, phase I clinical trial was undertaken at three dermatology clinics to evaluate the safety and tolerability of topical administration of an ointment containing 10% sheep polyclonal anti-nfP2X7 antibodies (BIL010t) to primary BCC lesions twice daily for 28 days. Twenty-one patients with primary BCC lesions at least 0·5 cm2 in area and less than 2·0 cm in diameter were enrolled. The primary end points were safety, tolerability and pharmacokinetics. Change in lesion size after treatment was determined and histology was performed on pretreatment and end-of-treatment (EOT) biopsies. RESULTS: Compliance was very high, with treatment being well tolerated. The most common adverse events were treatment site erythema, pruritus, dryness and pain. There was no evidence of systemic penetration of the sheep antibody. Lesions were measured prior to and after 28 days of treatment, with 65% of patients showing a reduction in lesion area, 20% showing no change and 15% showing an increase. Histopathology of post-treatment excision of lesion sites showed eight patients with stable disease, nine with partial response and three with complete response. CONCLUSIONS: Antibodies against nfP2X7 (BIL010t) provide a novel, safe and well-tolerated treatment for BCC.


Assuntos
Anticorpos/administração & dosagem , Antineoplásicos/administração & dosagem , Carcinoma Basocelular/tratamento farmacológico , Receptores Purinérgicos P2X7/imunologia , Neoplasias Cutâneas/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Animais , Anticorpos/efeitos adversos , Anticorpos/farmacologia , Antineoplásicos/efeitos adversos , Antineoplásicos/farmacocinética , Esquema de Medicação , Feminino , Humanos , Imunoglobulina G/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Transplante de Neoplasias , Pomadas , Transplante Heterólogo , Resultado do Tratamento
5.
Sci Justice ; 56(2): 90-5, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26976466

RESUMO

The UK and Ireland Association of Forensic Science Providers' (AFSP) Body Fluid Forum (BFF) set out to assist in the interpretation of sexual offence cases where semen is absent on vaginal swabs but female DNA is present on penile swabs or male underwear, and the issue to be addressed is whether or not sexual intercourse occurred. This study aims to investigate the frequency and amount of female DNA transferred to the penis and underwear of males following staged nonintimate social contact with females and to compare the findings with the amount of female DNA transferred to the penis and subsequently to the underwear of a male who had engaged in unprotected sexual intercourse with a female. In this study, no matching female DNA was detected on the inside front of the 44 items of male underwear used in this research following staged contact of a nonintimate nature and subsequent secondary transfer to the penis. After sexual intercourse, full profiles matching the female participant were found on the inside front of the males underwear with maximum peak heights in the range between 1898 and 3157 rfu. It was possible to demonstrate that DNA can occasionally transfer to the waistband and outside front of underwear worn by a male following staged nonintimate social contact. Data obtained in this study suggest that a matching female DNA profile below a peak height of 1000 rfu on the waistband of a male's underwear might be explained by nonintimate social contact with secondary transfer of female DNA from the male's hands.


Assuntos
Vestuário , DNA/isolamento & purificação , Tato , Coito , Impressões Digitais de DNA , Feminino , Humanos , Masculino
6.
J Antimicrob Chemother ; 69(12): 3259-62, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25063776

RESUMO

OBJECTIVES: To examine the prevalence of multidrug-resistant (MDR) urinary Escherichia coli among US outpatients and to assess the antimicrobial activity of oral antibiotics commonly used to treat urinary tract infections (UTIs) against MDR isolates. METHODS: Antimicrobial susceptibility testing data from outpatient urine cultures in The Surveillance Network (TSN) Database USA were analysed. Six antimicrobial agents from six separate drug classes were included: ampicillin, cefalotin, ciprofloxacin, nitrofurantoin, trimethoprim/sulfamethoxazole and amoxicillin/clavulanate. Isolates were categorized as resistant to one, two, three, four, five and six agents and compared for the years 2001 and 2010. Phenotypes of MDR isolates were assessed to determine antimicrobial activity of recommended therapy for UTIs. RESULTS: Prevalence of MDR E. coli increased from 9.1% in 2001 (n = 29,198) to 17.0% in 2010 (n = 32,742) (P < 0.0001). In isolates that demonstrated resistance to three, four or five antimicrobial agents in 2010, resistance to nitrofurantoin was observed in only 2.1%, 7.5% and 24.1% of isolates, respectively. Conversely, widespread resistance was observed for trimethoprim/sulfamethoxazole (62.6%, 88.6% and 97.9% for isolates resistant to three, four and five agents, respectively) and ciprofloxacin (48.9%, 84.3% and 98.2% for isolates resistant to three, four and five agents, respectively). CONCLUSIONS: Because of its consistent antimicrobial activity against MDR E. coli, nitrofurantoin remains a reliable first-line agent for the empirical treatment of acute uncomplicated cystitis.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Infecções por Escherichia coli/microbiologia , Escherichia coli/efeitos dos fármacos , Nitrofurantoína/farmacologia , Infecções Urinárias/microbiologia , Escherichia coli/isolamento & purificação , Humanos , Testes de Sensibilidade Microbiana , Pacientes Ambulatoriais , Estados Unidos
7.
Anim Genet ; 45(4): 542-9, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24835129

RESUMO

Cranial cruciate ligament rupture (CCLR) is the most common cause of pelvic limb lameness in dogs. To investigate the genetic basis of canine CCLR, we conducted a genome-wide association study using a canine SNP array in Newfoundland pedigree dogs with and without CCLR (n = 96). We identified three main chromosomal regions of CCLR association (on chromosomes 1, 3 and 33). Each of these regions was confirmed by Sequenom genotyping in a further cohort of Newfoundlands (n = 271). The results, particularly SNPs identified in the SORCS2 and SEMA5B genes, suggest that there may be neurological pathways involved in susceptibility to canine CCLR.


Assuntos
Lesões do Ligamento Cruzado Anterior , Doenças do Cão/genética , Cães/lesões , Estudo de Associação Genômica Ampla/veterinária , Polimorfismo de Nucleotídeo Único , Animais , Doenças do Cão/epidemiologia , Especificidade da Espécie
8.
Eur Heart J ; 34(21): 1567-74, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23391586

RESUMO

AIMS: The pathophysiology of aortic stenosis shares many similarities with atherosclerosis and skeletal bone formation. Using non-invasive imaging, we compared aortic valve calcification and inflammation activity with that measured in atherosclerosis and bone. METHODS AND RESULTS: Positron emission and computed tomography was performed using 18F-sodium fluoride (18F-NaF, calcification) and 18F-fluorodeoxyglucose (18F-FDG, inflammation) in 101 patients with calcific aortic valve disease (81 aortic stenosis and 20 aortic sclerosis). Calcium scores and positron emission tomography tracer activity (tissue-to-background ratio; TBR) were measured in the aortic valve, coronary arteries, thoracic aorta, and bone. Over 90% of the cohort had coexistent calcific atheroma, yet correlations between calcium scores were weak or absent (valve vs. aorta r(2) = 0.015, P = 0.222; valve vs. coronaries r(2) = 0.039, P = 0.049) as were associations between calcium scores and bone mineral density (BMD vs. valve r(2) = 0.000, P = 0.766; vs. aorta r(2) = 0.052, P = 0.025; vs. coronaries r(2) = 0.016, P = 0.210). 18F-NaF activity in the valve was 28% higher than in the aorta (TBR: 2.66 ± 0.84 vs. 2.11 ± 0.31, respectively, P < 0.001) and correlated more strongly with the severity of aortic stenosis (r(2) = 0.419, P < 0.001) than 18F-NaF activity outwith the valve (valve vs. aorta r(2) = 0.167, P < 0.001; valve vs. coronary arteries r(2) = 0.174, P < 0.001; valve vs. bone r(2) = 0.001, P = 0.806). In contrast, 18F-FDG activity was lower in the aortic valve than the aortic atheroma (TBR: 1.56 ± 0.21 vs. 1.81 ± 0.24, respectively, P < 0.001) and more closely associated with uptake outwith the valve (valve vs. aorta r(2) = 0.327, P < 0.001). CONCLUSION: In patients with aortic stenosis, disease activity appears to be determined by local calcific processes within the valve that are distinct from atherosclerosis and skeletal bone metabolism.


Assuntos
Estenose da Valva Aórtica/patologia , Valva Aórtica/patologia , Aterosclerose/patologia , Calcinose/patologia , Osteíte/patologia , Vasculite/patologia , Idoso , Valva Aórtica/diagnóstico por imagem , Estenose da Valva Aórtica/diagnóstico por imagem , Aterosclerose/diagnóstico por imagem , Densidade Óssea , Calcinose/diagnóstico por imagem , Feminino , Fluordesoxiglucose F18 , Humanos , Masculino , Osteíte/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Fluoreto de Sódio , Tomografia Computadorizada por Raios X , Vasculite/diagnóstico por imagem
9.
Neuropsychol Rehabil ; 24(1): 125-43, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24256344

RESUMO

Music evoked autobiographical memories (MEAMs) have been characterised in the healthy population, but not, to date, in patients with acquired brain injury (ABI). Our aim was to investigate music compared with verbal evoked autobiographical memories. Five patients with severe ABI and matched controls completed the experimental music (MEAM) task (a written questionnaire) while listening to 50 "Number 1 Songs of the Year" (from 1960 to 2010). Patients also completed the Autobiographical Memory Interview (AMI) and a standard neuropsychological assessment. With the exception of Case 5, who reported no MEAMs and no autobiographical incidents on the AMI and who also had impaired pitch perception, the range of frequency and type of MEAMs in patients was broadly in keeping with their matched controls. The relative preservation of MEAMs in four cases was particularly noteworthy given their impaired verbal and/or visual anterograde memory, and in three cases, autobiographical memory impairment. The majority of MEAMs in both cases and matched controls were of a person/people or a period of life. In three patients music was more efficient at evoking autobiographical memories than the AMI verbal prompts. This is the first study of MEAMs after ABI. The findings suggest that music is an effective stimulus for eliciting autobiographical memories, and may be beneficial in the rehabilitation of autobiographical amnesia, but only in patients without a fundamental deficit in autobiographical recall memory and intact pitch perception.


Assuntos
Lesões Encefálicas/psicologia , Memória Episódica , Música , Adulto , Humanos , Masculino , Rememoração Mental , Pessoa de Meia-Idade
10.
Proc Biol Sci ; 280(1763): 20130818, 2013 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-23698011

RESUMO

Species richness gradients are ubiquitous in nature, but the mechanisms that generate and maintain these patterns at macroecological scales remain unresolved. We use a new approach that focuses on overlapping geographical ranges of species to reveal that Indo-Pacific corals are assembled within 11 distinct faunal provinces. Province limits are characterized by co-occurrence of multiple species range boundaries. Unexpectedly, these faunal breaks are poorly predicted by contemporary environmental conditions and the present-day distribution of habitat. Instead, faunal breaks show striking concordance with geological features (tectonic plates and mantle plume tracks). The depth range over which a species occurs, its larval development rate and genus age are important determinants of the likelihood that species will straddle faunal breaks. Our findings indicate that historical processes, habitat heterogeneity and species colonization ability account for more of the present-day biogeographical patterns of corals than explanations based on the contemporary distribution of reefs or environmental conditions.


Assuntos
Antozoários/classificação , Antozoários/fisiologia , Ecossistema , Fenômenos Geológicos , Animais , Recifes de Corais , Fenômenos Ecológicos e Ambientais , Meio Ambiente , Oceano Pacífico , Especificidade da Espécie
11.
Mol Phylogenet Evol ; 67(1): 167-75, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23353071

RESUMO

The crested newt Triturus cristatus superspecies is composed of five recognized species. One of these, T. karelinii sensu lato, comprises three geographically structured mitochondrial DNA lineages: 'eastern', 'central' and 'western T. karelinii'. Genetic divergence among these lineages is comparable to that of recognized crested newt species, but morphologically they are indistinguishable. Here, we conduct a multimarker phylogeographical survey to explore the evolutionary independence of these mitochondrial DNA lineages and we include representatives of the other species to guide our interpretation of the results. All markers show distinct patterns when analyzed singly (as a phylogeny or haplotype network) and none of them sort haplotypes fully in line with species or mitochondrial DNA lineage. A multilocus approach (BAPS and *BEAST) on the other hand shows that not only the recognized species, but also the three mitochondrial DNA lineages represent discrete nuclear DNA gene pools. A mismatch is found in the northwest of Asiatic Turkey, where several populations identified as 'central T. karelinii' based on nuclear DNA possesses 'western T. karelinii' mitochondrial DNA. We invoke asymmetric mitochondrial DNA introgression to explain this pattern and support this with a historical biogeographical scenario. The three spatial groups in T. karelinii sensu lato should be regarded as distinct species.


Assuntos
Evolução Molecular , Filogenia , Triturus/classificação , Animais , Teorema de Bayes , Núcleo Celular/genética , DNA Mitocondrial/genética , Pool Gênico , Genética Populacional , Haplótipos , Modelos Genéticos , Filogeografia , Análise de Sequência de DNA , Triturus/genética
12.
Mol Psychiatry ; 17(10): 988-95, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22105622

RESUMO

Attention-deficit hyperactivity disorder (ADHD) in adults is associated with impaired sleep, and it has been postulated that this impairment may contribute to the psychopathology of this common condition. One key driver of sleep/wake cycles is the circadian system, which at the molecular level consists of a series of transcriptional feedback loops of clock genes, which in turn produce endocrine, physiological and behavioural outputs with a near 24 h periodicity. We set out to examine circadian rhythms at the behavioural, endocrine and molecular levels in ADHD. Adults with ADHD as well as age- and sex-matched controls were recruited. Circadian rhythms were measured by means of actigraphy for the determination of gross motor patterns, by self-sampling of oral mucosa for assessment of rhythmic expression of the clock genes BMAL1 and PER2, and by estimation of salivary cortisol and melatonin levels. Actigraphic analysis revealed significant diurnal and nocturnal hyperactivity in the ADHD group, as well as a significant shorter period of best fit for the locomotor circadian rhythm in ADHD. BMAL1 and PER2 showed circadian rhythmicity in controls with this being lost in the ADHD group. Cortisol rhythms were significantly phase delayed in the ADHD group. These findings indicate that adult ADHD is accompanied by significant changes in the circadian system, which in turn may lead to decreased sleep duration and quality in the condition. Further, modulation of circadian rhythms may represent a novel therapeutic avenue in the management of ADHD.


Assuntos
Fatores de Transcrição ARNTL/genética , Transtorno do Deficit de Atenção com Hiperatividade , Ritmo Circadiano/fisiologia , Sistema Endócrino/fisiopatologia , Proteínas Circadianas Period/genética , Actigrafia , Adulto , Transtorno do Deficit de Atenção com Hiperatividade/genética , Transtorno do Deficit de Atenção com Hiperatividade/metabolismo , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Estudos de Casos e Controles , Manual Diagnóstico e Estatístico de Transtornos Mentais , Feminino , Humanos , Hidrocortisona/metabolismo , Masculino , Melatonina/metabolismo , Pessoa de Meia-Idade , Psicometria , Estudos Retrospectivos , Saliva/metabolismo , Autorrelato , Estatísticas não Paramétricas , Inquéritos e Questionários , Fatores de Tempo , Adulto Jovem
13.
Clin Radiol ; 68(11): e570-7, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23838086

RESUMO

AIM: To assess the effect of two iterative reconstruction algorithms (AIDR and AIDR3D) and individualized automatic tube current selection on radiation dose and image quality in computed tomography coronary angiography (CTCA). MATERIALS AND METHODS: In a single-centre cohort study, 942 patients underwent electrocardiogram-gated CTCA using a 320-multidetector CT system. Images from group 1 (n = 228) were reconstructed with a filtered back projection algorithm (Quantum Denoising Software, QDS+). Iterative reconstruction was used for group 2 (AIDR, n = 379) and group 3 (AIDR3D, n = 335). Tube current was selected based on body mass index (BMI) for groups 1 and 2, and selected automatically based on scout image attenuation for group 3. Subjective image quality was graded on a four-point scale (1 = excellent, 4 = non-diagnostic). RESULTS: There were no differences in age (p = 0.975), body mass index (p = 0.435), or heart rate (p = 0.746) between the groups. Image quality improved with iterative reconstruction and automatic tube current selection [1.3 (95% confidence intervals (CI): 1.2-1.4), 1.2 (1.1-1.2) and 1.1 (1-1.2) respectively; p < 0.001] and radiation dose decreased [274 (260-290), 242 (230-253) and 168 (156-180) mGy cm, respectively; p < 0.001]. CONCLUSION: The application of the latest iterative reconstruction algorithm and individualized automatic tube current selection can substantially reduce radiation dose whilst improving image quality in CTCA.


Assuntos
Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Tomografia Computadorizada Multidetectores/métodos , Doses de Radiação , Algoritmos , Estudos de Coortes , Meios de Contraste , Eletrocardiografia/métodos , Feminino , Humanos , Iopamidol/análogos & derivados , Masculino , Pessoa de Meia-Idade , Proteção Radiológica/métodos , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos
14.
Sci Justice ; 53(4): 385-94, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24188339

RESUMO

Acid phosphatase (AP) reagent (Fast Black) is used as a presumptive test for the presence of seminal fluid on exhibits submitted in allegations of sexual assault. Research was carried out to determine whether the direct application of AP reagent to exhibits is a viable alternative to the traditional indirect (blot) testing method used routinely in the laboratory. The relative sensitivity of the indirect and direct testing methods was investigated as was the effect of AP reagent on histological staining of spermatozoa, the incidence of false positives from vaginal material and saliva, and the effect of AP reagent on subsequent DNA testing. Also included are the results of specificity studies from validations of the direct AP testing method. The results of this research show that, provided the incidence of false positives is borne in mind, direct AP testing can be especially useful when screening exhibits which are difficult to indirectly (blot) AP test or when it is problematic to relocate an AP positive stain. Direct application of AP reagent can also be beneficial for locating dilute semen stains. Three case examples are given which illustrate the use of direct AP testing in laboratory casework.


Assuntos
Fosfatase Ácida/análise , Ensaios Enzimáticos Clínicos/métodos , Sêmen/enzimologia , Impressões Digitais de DNA , Feminino , Humanos , Indicadores e Reagentes , Masculino , Sensibilidade e Especificidade , Espermatozoides/enzimologia
15.
Sci Justice ; 63(4): 477-484, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37453779

RESUMO

The Body Fluid Forum of the Association of Forensic Science Providers recognised concerns raised by forensic practitioners regarding the lack of data to inform on the incidence of significant AP (Acid Phosphatase) reactions from vaginal and oral samples, i.e. those which might be misinterpreted as indicating the presence of semen. This is particularly relevant in the light of appeal court rulings regarding the need for data to support evaluations. This paper presents collaborative data on the nature and incidence of AP reactions from vaginal and oral swabs provided by donors. The results demonstrate that caution is required with mid to strong purple AP reactions from direct testing of oral swabs and with mid purple reactions from vaginal swabs. The use of a Bayesian approach to assist with the provision of opinions regarding the presence of seminal fluid is highlighted.


Assuntos
Fosfatase Ácida , Líquidos Corporais , Feminino , Humanos , Teorema de Bayes , Sêmen , Vagina
16.
Proc Natl Acad Sci U S A ; 106(25): 10109-13, 2009 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-19509340

RESUMO

This study challenges the paradigm that salt marsh plants prevent lateral wave-induced erosion along wetland edges by binding soil with live roots and clarifies the role of vegetation in protecting the coast. In both laboratory flume studies and controlled field experiments, we show that common salt marsh plants do not significantly mitigate the total amount of erosion along a wetland edge. We found that the soil type is the primary variable that influences the lateral erosion rate and although plants do not directly reduce wetland edge erosion, they may do so indirectly via modification of soil parameters. We conclude that coastal vegetation is best-suited to modify and control sedimentary dynamics in response to gradual phenomena like sea-level rise or tidal forces, but is less well-suited to resist punctuated disturbances at the seaward margin of salt marshes, specifically breaking waves.


Assuntos
Desenvolvimento Vegetal , Salinidade , Cloreto de Sódio/química , Solo , Áreas Alagadas
17.
J Adv Model Earth Syst ; 14(3): e2021MS002784, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35860446

RESUMO

Tropical peatlands are among the most carbon-dense ecosystems on Earth, and their water storage dynamics strongly control these carbon stocks. The hydrological functioning of tropical peatlands differs from that of northern peatlands, which has not yet been accounted for in global land surface models (LSMs). Here, we integrated tropical peat-specific hydrology modules into a global LSM for the first time, by utilizing the peatland-specific model structure adaptation (PEATCLSM) of the NASA Catchment Land Surface Model (CLSM). We developed literature-based parameter sets for natural (PEATCLSMTrop,Nat) and drained (PEATCLSMTrop,Drain) tropical peatlands. Simulations with PEATCLSMTrop,Nat were compared against those with the default CLSM version and the northern version of PEATCLSM (PEATCLSMNorth,Nat) with tropical vegetation input. All simulations were forced with global meteorological reanalysis input data for the major tropical peatland regions in Central and South America, the Congo Basin, and Southeast Asia. The evaluation against a unique and extensive data set of in situ water level and eddy covariance-derived evapotranspiration showed an overall improvement in bias and correlation compared to the default CLSM version. Over Southeast Asia, an additional simulation with PEATCLSMTrop,Drain was run to address the large fraction of drained tropical peatlands in this region. PEATCLSMTrop,Drain outperformed CLSM, PEATCLSMNorth,Nat, and PEATCLSMTrop,Nat over drained sites. Despite the overall improvements of PEATCLSMTrop,Nat over CLSM, there are strong differences in performance between the three study regions. We attribute these performance differences to regional differences in accuracy of meteorological forcing data, and differences in peatland hydrologic response that are not yet captured by our model.

18.
Nat Med ; 1(1): 53-8, 1995 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-7584953

RESUMO

The clinical use of fetal neural grafts as an intracerebral source of dopamine for patients with Parkinson's disease has met with limited success. Since basic fibroblast growth factor (bFGF) enhances the survival and growth of dopaminergic neurons in vitro, we explored whether cells genetically modified to produce bFGF would improve the functional efficacy of dopaminergic neurons implanted into rats with experimental Parkinson's disease. Results show that bFGF-producing cells grafted together with fetal dopamine neurons have potent growth-promoting effects on the implanted neurons in vivo. Moreover, rats implanted with such co-grafts display the most pronounced behavioural improvements post-grafting. These findings not only provide insight into the function of bFGF in situ, but also suggest an approach for enhancing the survival and function of dopamine neurons grafted into the damaged brain.


Assuntos
Dopamina/fisiologia , Fator 2 de Crescimento de Fibroblastos/farmacologia , Mesencéfalo/transplante , Animais , Comportamento Animal/fisiologia , Modelos Animais de Doenças , Feminino , Fibroblastos/citologia , Sobrevivência de Enxerto/efeitos dos fármacos , Doença de Parkinson/terapia , Ratos , Ratos Endogâmicos F344 , Transfecção
19.
J Exp Med ; 188(12): 2233-41, 1998 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-9858510

RESUMO

VDJ recombination of T cell receptor and immunoglobulin loci occurs in immature lymphoid cells. Although the molecular mechanisms of DNA cleavage and ligation have become more clear, it is not understood what controls which target loci undergo rearrangement. In interleukin 7 receptor (IL-7R)alpha-/- murine thymocytes, it has been shown that rearrangement of the T cell receptor (TCR)-gamma locus is virtually abrogated, whereas other rearranging loci are less severely affected. By examining different strains of mice with targeted mutations, we now observe that the signaling pathway leading from IL-7Ralpha to rearrangement of the TCR-gamma locus requires the gammac receptor chain and the gammac-associated Janus kinase Jak3. Production of sterile transcripts from the TCR-gamma locus, a process that generally precedes rearrangement of a locus, was greatly repressed in IL-7Ralpha-/- thymocytes. The repressed transcription was not due to a lack in transcription factors since the three transcription factors known to regulate this locus were readily detected in IL-7Ralpha-/- thymocytes. Instead, the TCR-gamma locus was shown to be methylated in IL-7Ralpha-/- thymocytes. Treatment of IL-7Ralpha-/- precursor T cells with the specific histone deacetylase inhibitor trichostatin A released the block of TCR-gamma gene rearrangement. This data supports the model that IL-7R promotes TCR-gamma gene rearrangement by regulating accessibility of the locus via demethylation and histone acetylation of the locus.


Assuntos
Rearranjo Gênico da Cadeia gama dos Receptores de Antígenos dos Linfócitos T/genética , Células-Tronco Hematopoéticas/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/genética , Receptores de Interleucina-7/metabolismo , Linfócitos T/imunologia , Animais , Células da Medula Óssea , Cromatina/metabolismo , DNA/metabolismo , Metilação de DNA , Elementos Facilitadores Genéticos/genética , Inibidores Enzimáticos/farmacologia , Rearranjo Gênico da Cadeia gama dos Receptores de Antígenos dos Linfócitos T/efeitos dos fármacos , Genes RAG-1/genética , Genes RAG-1/fisiologia , Células-Tronco Hematopoéticas/metabolismo , Inibidores de Histona Desacetilases , Histona Desacetilases/metabolismo , Ácidos Hidroxâmicos/farmacologia , Janus Quinase 3 , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , RNA/biossíntese , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Receptores de Interleucina-7/genética , Linfócitos T/metabolismo , Timo/efeitos dos fármacos , Timo/embriologia , Fatores de Transcrição/metabolismo
20.
Am J Physiol Gastrointest Liver Physiol ; 298(3): G345-51, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19926813

RESUMO

Facilitative UT-B urea transporters enable the passage of urea across cell membranes. Gastrointestinal urea transporters are thought to play a significant role in the urea nitrogen salvaging process that occurs between mammalian hosts and their gut bacteria. This study investigated the expression of UT-B urea transporters in different segments of human colon. Immunoblot analysis showed that human colon expressed a 35-kDa glycosylated UT-B protein in the colonic mucosa. The 35-kDa UT-B transporter was predominantly located in plasma membrane-enriched samples (P < 0.001; n = 6), and its expression was greater in the ascending colon compared with the descending colon (P < 0.01; n = 3). At the cellular level, UT-B transporters were located throughout colonocytes situated in the upper portion of the colonic crypts. Bidirectional trans-epithelial urea transport was significantly greater in the ascending colon than the descending colon (P < 0.05; n = 6). In addition, the facilitative urea transporter inhibitor 1,3,dimethylurea significantly reduced urea transport in the ascending colon (P < 0.05; n = 6) but had no effect in the descending colon (NS; n = 6). These results illustrate differential protein abundance of functional UT-B protein in different sections of the human colon, strongly correlating to regions that contain the largest populations of intestinal bacteria. This study suggests an important role for UT-B urea transporters in maintaining the symbiotic relationship between humans and their gut bacteria.


Assuntos
Colo/fisiologia , Proteínas de Membrana Transportadoras/fisiologia , Carbacol/farmacologia , Membrana Celular/metabolismo , Colo/efeitos dos fármacos , Colo Ascendente/efeitos dos fármacos , Colo Ascendente/fisiologia , Colo Descendente/efeitos dos fármacos , Colo Descendente/fisiologia , Citoplasma/metabolismo , Impedância Elétrica , Fenômenos Eletrofisiológicos/fisiologia , Células Epiteliais/metabolismo , Glicosilação , Humanos , Mucosa Intestinal/metabolismo , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Compostos de Metilureia/farmacologia , Músculo Liso/metabolismo , Ureia/análogos & derivados , Ureia/metabolismo , Transportadores de Ureia
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