Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Ecol Appl ; 33(1): e2743, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36107148

RESUMO

There is increasing evidence that farmers in many areas are achieving below maximum yields due to insufficient pollination. Practical and effective approaches are needed to maintain wild pollinator populations within agroecosystems so they can deliver critical pollination services that underpin crop production. We established nesting and wildflower habitat interventions in 24 UK apple orchards and measured effects on flower-visiting insects and the pollination they provide, exploring how this was affected by landscape context. We quantified the extent of pollination deficits and assessed whether the management of wild pollinators can reduce deficits and deliver improved outcomes for growers over 3 years. Wildflower interventions increased solitary bee numbers visiting apple flowers by over 20%, but there was no effect of nesting interventions. Other pollinator groups were influenced by both local and landscape-scale factors, with bumblebees and hoverflies responding to the relative proportion of semi-natural habitat at larger spatial scales (1000 m), while honeybees and other flies responded at 500 m or less. By improving fruit number and quality, pollinators contributed more than £16 k per hectare. However, deficits (where maximum potential was not being reached due to a lack of pollination) were recorded and the extent of these varied across orchards, and from year to year, with a 22% deficit in output in the worst (equivalent to ~£14 k/ha) compared to less than 3% (equivalent to ~£2 k/ha) in the best year. Although no direct effect of our habitat interventions on deficits in gross output was observed, initial fruit set and seed set deficits were reduced by abundant bumblebees, and orchards with a greater abundance of solitary bees saw lower deficits in fruit size. The abundance of pollinators in apple orchards is influenced by different local and landscape factors that interact and vary between years. Consequently, pollination, and the extent of economic output deficits, also vary between orchards and years. We highlight how approaches, including establishing wildflower areas and optimizing the ratio of cropped and non-cropped habitats can increase the abundance of key apple pollinators and improve outcomes for growers.


Assuntos
Malus , Polinização , Abelhas , Animais , Ecossistema , Insetos , Frutas , Produtos Agrícolas , Flores
2.
J Pharmacol Exp Ther ; 380(3): 143-152, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34893551

RESUMO

Dopamine (DA) plays a key role in several central functions including cognition, motor activity, and wakefulness. Although efforts to develop dopamine receptor 1 (D1) agonists have been challenging, a positive allosteric modulator represents an attractive approach with potential better drug-like properties. Our previous study demonstrated an acceptable safety and tolerability profile of the dopamine receptor 1 positive allosteric modulator (D1PAM) mevidalen (LY3154207) in single and multiple ascending dose studies in healthy volunteers (Wilbraham et al., 2021). Herein, we describe the effects of mevidalen on sleep and wakefulness in humanized dopamine receptor 1 (hD1) mice and in sleep-deprived healthy male volunteers. Mevidalen enhanced wakefulness (latency to fall asleep) in the hD1 mouse in a dose dependent [3-100 mg/kg, orally (PO)] fashion when measured during the light (zeitgeber time 5) and predominantly inactive phase. Mevidalen promoted wakefulness in mice after prior sleep deprivation and delayed sleep onset by 5.5- and 15.2-fold compared with vehicle-treated animals, after the 20 and 60 mg/kg PO doses, respectively, when compared with vehicle-treated animals. In humans, mevidalen demonstrated a dose-dependent increase in latency to sleep onset as measured by the multiple sleep latency test and all doses (15, 30, and 75 mg) separated from placebo at the first 2-hour postdose time point with a circadian effect at the 6-hour postdose time point. Sleep wakefulness should be considered a translational biomarker for the dopamine receptor 1 positive allosteric modulator mechanism. SIGNIFICANCE STATEMENT: This is the first translational study describing the effects of a selective dopamine receptor 1 positive allosteric modulator (D1PAM) on sleep and wakefulness in the human dopamine receptor 1 mouse and in sleep-deprived healthy male volunteers. In both species, drug exposure correlated with sleep latency, supporting the use of sleep-wake activity as a translational central biomarker for D1PAM. Wake-promoting effects of D1PAMs may offer therapeutic opportunities in several conditions, including sleep disorders and excessive daytime sleepiness related to neurodegenerative disorders.


Assuntos
Fármacos Neuroprotetores , Vigília , Animais , Voluntários Saudáveis , Humanos , Isoquinolinas , Masculino , Camundongos , Fármacos Neuroprotetores/farmacologia , Receptores de Dopamina D1 , Sono/fisiologia
3.
Respir Res ; 23(1): 202, 2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-35945604

RESUMO

BACKGROUND: The efficacy and safety of complement inhibition in COVID-19 patients is unclear. METHODS: A multicenter randomized controlled, open-label trial. Hospitalized COVID-19 patients with signs of systemic inflammation and hypoxemia (PaO2/FiO2 below 350 mmHg) were randomized (2:1 ratio) to receive standard of care with or without the C5 inhibitor zilucoplan daily for 14 days, under antibiotic prophylaxis. The primary outcome was improvement in oxygenation at day 6 and 15. RESULTS: 81 patients were randomly assigned to zilucoplan (n = 55) or the control group (n = 26). 78 patients were included in the safety and primary analysis. Most were men (87%) and the median age was 63 years. The mean improvement in PaO2/FiO2 from baseline to day 6 was 56.4 mmHg in the zilucoplan group and 20.6 mmHg in the control group (mean difference + 35.8; 95% confidence interval (CI) - 9.4 to 80.9; p = 0.12), an effect also observed at day 15. Day 28 mortality was 9% in the zilucoplan and 21% in the control group (odds ratio 0.4; 95% CI 0.1 to 1.5). At long-term follow up, the distance walked in a 6-min test was 539.7 m in zilucoplan and 490.6 m in the control group (p = 0.18). Zilucoplan lowered serum C5b-9 (p < 0.001) and interleukin-8 (p = 0.03) concentration compared with control. No relevant safety differences between the zilucoplan and control group were identified. CONCLUSION: Administration of zilucoplan to COVID-19 patients in this proof-of-concept randomized trial was well tolerated under antibiotic prophylaxis. While not reaching statistical significance, indicators of respiratory function (PaO2/FiO2) and clinical outcome (mortality and 6-min walk test) suggest that C5 inhibition might be beneficial, although this requires further research in larger randomized studies.


Assuntos
Anti-Infecciosos , Tratamento Farmacológico da COVID-19 , Complemento C5 , Inativadores do Complemento/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Peptídeos Cíclicos , SARS-CoV-2 , Resultado do Tratamento
4.
Proc Biol Sci ; 288(1947): 20210212, 2021 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-33726596

RESUMO

While an increasing number of studies indicate that the range, diversity and abundance of many wild pollinators has declined, the global area of pollinator-dependent crops has significantly increased over the last few decades. Crop pollination studies to date have mainly focused on either identifying different guilds pollinating various crops, or on factors driving spatial changes and turnover observed in these communities. The mechanisms driving temporal stability for ecosystem functioning and services, however, remain poorly understood. Our study quantifies temporal variability observed in crop pollinators in 21 different crops across multiple years at a global scale. Using data from 43 studies from six continents, we show that (i) higher pollinator diversity confers greater inter-annual stability in pollinator communities, (ii) temporal variation observed in pollinator abundance is primarily driven by the three-most dominant species, and (iii) crops in tropical regions demonstrate higher inter-annual variability in pollinator species richness than crops in temperate regions. We highlight the importance of recognizing wild pollinator diversity in agricultural landscapes to stabilize pollinator persistence across years to protect both biodiversity and crop pollination services. Short-term agricultural management practices aimed at dominant species for stabilizing pollination services need to be considered alongside longer term conservation goals focussed on maintaining and facilitating biodiversity to confer ecological stability.


Assuntos
Ecossistema , Polinização , Agricultura , Animais , Abelhas , Biodiversidade , Produtos Agrícolas , Insetos
5.
Rheumatology (Oxford) ; 60(11): 5397-5407, 2021 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-33956056

RESUMO

OBJECTIVE: To evaluate the dose-response, efficacy and safety of dapirolizumab pegol (DZP) in patients with SLE. METHODS: Adults with moderately to severely active SLE (SLEDAI-2K score ≥6 and ≥1 BILAG A or ≥2 BILAG B domain scores), receiving stable CS (≤40 mg/day prednisone-equivalent), antimalarial or immunosuppressant drugs were included. Patients with stable LN (proteinuria ≤2 g/day) not receiving high-dose CS or CYC were permitted entry. Randomized patients received placebo or i.v. DZP (6/24/45 mg/kg) and standard-of-care (SOC) treatment every 4 weeks to week 24, after which patients received only SOC to week 48. The primary objective was to establish a dose-response relationship based on week 24 BILAG-Based Composite Lupus Assessment (BICLA) responder rates. RESULTS: All DZP groups exhibited improvements in clinical and immunological outcomes vs placebo at week 24; however, BICLA responder rates did not fit pre-specified dose-response models [best-fitting model (Emax): P = 0.07]. Incidences of serious treatment-emergent adverse events across DZP groups were low and similar to placebo. Following DZP withdrawal, SLEDAI-2K, physician's global assessment (PGA), BILAG, and Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) scores stabilized; BICLA and SLE Responder Index (SRI-4) responder rates declined (likely due to interventions with disallowed escape medications), BILAG flares increased, and immunologic parameters returned towards baseline. CONCLUSIONS: Although the primary objective was not met, DZP appeared to be well tolerated, and patients exhibited improvements across multiple clinical and immunological measures of disease activity after 24 weeks relative to placebo. The potential clinical benefit of DZP warrants further investigation.


Assuntos
Fragmentos Fab das Imunoglobulinas/uso terapêutico , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Polietilenoglicóis/uso terapêutico , Adulto , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Fragmentos Fab das Imunoglobulinas/farmacologia , Lúpus Eritematoso Sistêmico/imunologia , Masculino , Pessoa de Meia-Idade , Polietilenoglicóis/farmacologia , Resultado do Tratamento
6.
Proc Natl Acad Sci U S A ; 113(1): 140-5, 2016 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-26699460

RESUMO

Wild bees are highly valuable pollinators. Along with managed honey bees, they provide a critical ecosystem service by ensuring stable pollination to agriculture and wild plant communities. Increasing concern about the welfare of both wild and managed pollinators, however, has prompted recent calls for national evaluation and action. Here, for the first time to our knowledge, we assess the status and trends of wild bees and their potential impacts on pollination services across the coterminous United States. We use a spatial habitat model, national land-cover data, and carefully quantified expert knowledge to estimate wild bee abundance and associated uncertainty. Between 2008 and 2013, modeled bee abundance declined across 23% of US land area. This decline was generally associated with conversion of natural habitats to row crops. We identify 139 counties where low bee abundances correspond to large areas of pollinator-dependent crops. These areas of mismatch between supply (wild bee abundance) and demand (cultivated area) for pollination comprise 39% of the pollinator-dependent crop area in the United States. Further, we find that the crops most highly dependent on pollinators tend to experience more severe mismatches between declining supply and increasing demand. These trends, should they continue, may increase costs for US farmers and may even destabilize crop production over time. National assessments such as this can help focus both scientific and political efforts to understand and sustain wild bees. As new information becomes available, repeated assessments can update findings, revise priorities, and track progress toward sustainable management of our nation's pollinators.


Assuntos
Abelhas/fisiologia , Produtos Agrícolas , Polinização , Animais , Fazendeiros , Humanos , Modelos Biológicos , Dinâmica Populacional , Estados Unidos
7.
Proc Natl Acad Sci U S A ; 113(1): 146-51, 2016 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-26621730

RESUMO

Wild and managed bees are well documented as effective pollinators of global crops of economic importance. However, the contributions by pollinators other than bees have been little explored despite their potential to contribute to crop production and stability in the face of environmental change. Non-bee pollinators include flies, beetles, moths, butterflies, wasps, ants, birds, and bats, among others. Here we focus on non-bee insects and synthesize 39 field studies from five continents that directly measured the crop pollination services provided by non-bees, honey bees, and other bees to compare the relative contributions of these taxa. Non-bees performed 25-50% of the total number of flower visits. Although non-bees were less effective pollinators than bees per flower visit, they made more visits; thus these two factors compensated for each other, resulting in pollination services rendered by non-bees that were similar to those provided by bees. In the subset of studies that measured fruit set, fruit set increased with non-bee insect visits independently of bee visitation rates, indicating that non-bee insects provide a unique benefit that is not provided by bees. We also show that non-bee insects are not as reliant as bees on the presence of remnant natural or seminatural habitat in the surrounding landscape. These results strongly suggest that non-bee insect pollinators play a significant role in global crop production and respond differently than bees to landscape structure, probably making their crop pollination services more robust to changes in land use. Non-bee insects provide a valuable service and provide potential insurance against bee population declines.


Assuntos
Produtos Agrícolas/crescimento & desenvolvimento , Insetos/fisiologia , Polinização , Animais , Formigas/fisiologia , Abelhas/fisiologia , Ecossistema , Flores/crescimento & desenvolvimento , Frutas/crescimento & desenvolvimento , Vespas/fisiologia
8.
Glob Chang Biol ; 23(11): 4946-4957, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28488295

RESUMO

Agricultural intensification is a leading cause of global biodiversity loss, which can reduce the provisioning of ecosystem services in managed ecosystems. Organic farming and plant diversification are farm management schemes that may mitigate potential ecological harm by increasing species richness and boosting related ecosystem services to agroecosystems. What remains unclear is the extent to which farm management schemes affect biodiversity components other than species richness, and whether impacts differ across spatial scales and landscape contexts. Using a global metadataset, we quantified the effects of organic farming and plant diversification on abundance, local diversity (communities within fields), and regional diversity (communities across fields) of arthropod pollinators, predators, herbivores, and detritivores. Both organic farming and higher in-field plant diversity enhanced arthropod abundance, particularly for rare taxa. This resulted in increased richness but decreased evenness. While these responses were stronger at local relative to regional scales, richness and abundance increased at both scales, and richness on farms embedded in complex relative to simple landscapes. Overall, both organic farming and in-field plant diversification exerted the strongest effects on pollinators and predators, suggesting these management schemes can facilitate ecosystem service providers without augmenting herbivore (pest) populations. Our results suggest that organic farming and plant diversification promote diverse arthropod metacommunities that may provide temporal and spatial stability of ecosystem service provisioning. Conserving diverse plant and arthropod communities in farming systems therefore requires sustainable practices that operate both within fields and across landscapes.


Assuntos
Agricultura/métodos , Artrópodes , Biodiversidade , Ecossistema , Animais
9.
Br J Clin Pharmacol ; 83(8): 1654-1667, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28156011

RESUMO

AIMS: The safety, tolerability, pharmacokinetics (PK) and pharmacodynamics of single and multiple doses of a novel mGlu2 agonist were assessed in healthy males. METHODS: In two, Phase 1 investigator- and subject-blind, placebo-controlled studies, oral doses of prodrug LY2979165 were evaluated: single doses (20-150 mg, N = 30) and multiple once-daily (QD) doses (20-400 mg; N = 84), using a titration regimen. The plasma and urine PK of LY2979165 and active moiety, 2812223, were measured. Cerebrospinal fluid (CSF) was collected to determine PK and neurotransmitter levels. Safety parameters were assessed throughout. RESULTS: Nausea and vomiting were dose limiting following single doses; dose titration allowed higher doses to be tested over 14 days. The most common adverse events related to LY2979165 were dizziness, vomiting, nausea, somnolence and headache. The plasma PK of 2812223 were approximately linear with minimal accumulation with QD dosing. Conversion of LY2979165 to 2812223 was extensive, with minimal LY2979165 measurable in plasma. There was no effect of food on the PK of LY2979165 and 2812223. After 60 mg LY2979165 single-dose, 2812223 exposure in CSF was approximately 2-6% and plasma exposure and peak concentrations were approximately four-fold higher than the mGlu2 agonist in vitro EC50 value. No consistent effects were observed on CSF neurotransmitter levels. CONCLUSIONS: Oral doses of LY2979165 up to 60 mg as a single dose and up to 400 mg given as multiple QD doses, using a titration regimen, were well tolerated with linear PK. Overall, these data support further clinical evaluation of LY2979165.


Assuntos
Compostos Bicíclicos com Pontes/farmacologia , Pró-Fármacos/farmacologia , Receptores de Glutamato Metabotrópico/agonistas , Triazóis/farmacologia , Administração Oral , Adulto , Idoso , Área Sob a Curva , Compostos Bicíclicos com Pontes/sangue , Compostos Bicíclicos com Pontes/líquido cefalorraquidiano , Compostos Bicíclicos com Pontes/urina , Estudos de Coortes , Distúrbios do Sono por Sonolência Excessiva/induzido quimicamente , Distúrbios do Sono por Sonolência Excessiva/epidemiologia , Tontura/induzido quimicamente , Tontura/epidemiologia , Relação Dose-Resposta a Droga , Método Duplo-Cego , Meia-Vida , Cefaleia , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Náusea/induzido quimicamente , Náusea/epidemiologia , Placebos , Triazóis/sangue , Triazóis/líquido cefalorraquidiano , Triazóis/urina , Vômito/induzido quimicamente , Vômito/epidemiologia , Adulto Jovem
10.
Ecol Lett ; 16(5): 584-99, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23489285

RESUMO

Bees provide essential pollination services that are potentially affected both by local farm management and the surrounding landscape. To better understand these different factors, we modelled the relative effects of landscape composition (nesting and floral resources within foraging distances), landscape configuration (patch shape, interpatch connectivity and habitat aggregation) and farm management (organic vs. conventional and local-scale field diversity), and their interactions, on wild bee abundance and richness for 39 crop systems globally. Bee abundance and richness were higher in diversified and organic fields and in landscapes comprising more high-quality habitats; bee richness on conventional fields with low diversity benefited most from high-quality surrounding land cover. Landscape configuration effects were weak. Bee responses varied slightly by biome. Our synthesis reveals that pollinator persistence will depend on both the maintenance of high-quality habitats around farms and on local management practices that may offset impacts of intensive monoculture agriculture.


Assuntos
Agricultura , Abelhas/fisiologia , Ecossistema , Modelos Teóricos , Polinização , Animais , Clima , Produtos Agrícolas , Flores , Densidade Demográfica
11.
Proc Biol Sci ; 280(1754): 20122767, 2013 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-23303545

RESUMO

In diverse pollinator communities, interspecific interactions may modify the behaviour and increase the pollination effectiveness of individual species. Because agricultural production reliant on pollination is growing, improving pollination effectiveness could increase crop yield without any increase in agricultural intensity or area. In California almond, a crop highly dependent on honey bee pollination, we explored the foraging behaviour and pollination effectiveness of honey bees in orchards with simple (honey bee only) and diverse (non-Apis bees present) bee communities. In orchards with non-Apis bees, the foraging behaviour of honey bees changed and the pollination effectiveness of a single honey bee visit was greater than in orchards where non-Apis bees were absent. This change translated to a greater proportion of fruit set in these orchards. Our field experiments show that increased pollinator diversity can synergistically increase pollination service, through species interactions that alter the behaviour and resulting functional quality of a dominant pollinator species. These results of functional synergy between species were supported by an additional controlled cage experiment with Osmia lignaria and Apis mellifera. Our findings highlight a largely unexplored facilitative component of the benefit of biodiversity to ecosystem services, and represent a way to improve pollinator-dependent crop yields in a sustainable manner.


Assuntos
Abelhas/fisiologia , Biodiversidade , Ecossistema , Polinização/fisiologia , Animais , Abelhas/genética , California , Polinização/genética , Prunus/crescimento & desenvolvimento , Estatísticas não Paramétricas
12.
Ecology ; 103(3): e3614, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34921678

RESUMO

Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open, and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e., berry mass, number of fruits, and fruit density [kg/ha], among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), North America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-2005 (21 studies), 2006-2010 (40), 2011-2015 (88), and 2016-2020 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA).


Assuntos
Ecossistema , Polinização , Animais , Abelhas , Produtos Agrícolas , Flores , Insetos
13.
Insects ; 12(8)2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34442306

RESUMO

(1) Modern, intensive agricultural practices have been attributed to the loss of insect biodiversity and abundance in agroecosystems for the last 80 years. The aim of this work is to test whether there are statistically significant differences in insect abundance between different zones and over time on the vineyard field. (2) The study was carried out in five intensive wine farms in Spain over a three-year period (2013-2015). Each field was divided into two zones, one where cover plants were planted, and another remained unchanged (without cover). (3) A clear trend to increase the average number of insect species and individuals throughout the years in all farms was observed. Moreover, the zones with cover plants showed a significant difference with respect to the zones without. (4) The use of permanent cover plants allows creating areas of refuge for the insects favouring their conservation and reducing the agriculture impact in the insect decline.

14.
Neuroimage ; 46(2): 447-58, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19233294

RESUMO

Antipsychotic-induced D2 receptor occupancy values tend to be lower when measured with [(123)I]IBZM SPECT than with [(11)C]Raclopride PET. To clarify this issue, D2 receptor occupancy was measured in the same subjects using both techniques. Twenty patients with schizophrenia on monotherapy with risperidone (n=7; 3-9 mg/d), olanzapine (n=5; 5-20 mg/d) or clozapine (n=8; 150-450 mg/d) at stable doses, and ten healthy volunteers (HV) underwent both a [(123)I]IBZM SPECT and a [(11)C]Raclopride PET examinations in random order on different days within a week. Patients with schizophrenia were scanned at a fixed interval after last dose administration. Quantification of receptor availability was performed using the most conventional methods from the literature: the tissue ratio derived specific uptake ratios (SUR) were used for SPECT, and simplified reference tissue model (SRTM) derived binding potentials (BP(ND)) for PET. Analysis was performed using both occipital cortex and cerebellum as reference regions for both modalities. Striatal D2 receptor occupancy was measured as the percentage reduction of [(123)I]IBZM SUR or [(11)C]Raclopride BP(ND) compared to the population average measured in HV using the same modality. Occupancy values measured by SPECT were lower than those measured with PET, by 12.4% and 13.8% when occipital cortex and cerebellum were used as reference regions. This difference should be taken in consideration when interpreting reported antipsychotic striatal D2 receptor occupancy values from the literature.


Assuntos
Benzamidas/farmacocinética , Corpo Estriado/diagnóstico por imagem , Corpo Estriado/metabolismo , Pirrolidinas/farmacocinética , Racloprida/farmacocinética , Receptores de Dopamina D2/metabolismo , Adulto , Feminino , Humanos , Masculino , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos/farmacocinética , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Distribuição Tecidual
15.
Parkinsonism Relat Disord ; 60: 138-145, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30201421

RESUMO

BACKGROUND: Progressive supranuclear palsy (PSP) -Richardson's Syndrome and Corticobasal Syndrome (CBS) are the two classic clinical syndromes associated with underlying four repeat (4R) tau pathology. The PSP Rating Scale is a commonly used assessment in PSP clinical trials; there is an increasing interest in designing combined 4R tauopathy clinical trials involving both CBS and PSP. OBJECTIVES: To determine contributions of each domain of the PSP Rating Scale to overall severity and characterize the probable sequence of clinical progression of PSP as compared to CBS. METHODS: Multicenter clinical trial and natural history study data were analyzed from 545 patients with PSP and 49 with CBS. Proportional odds models were applied to model normalized cross-sectional PSP Rating Scale, estimating the probability that a patient would experience impairment in each domain using the PSP Rating Scale total score as the index of overall disease severity. RESULTS: The earliest symptom domain to demonstrate impairment in PSP patients was most likely to be Ocular Motor, followed jointly by Gait/Midline and Daily Activities, then Limb Motor and Mentation, and finally Bulbar. For CBS, Limb Motor manifested first and ocular showed less probability of impairment throughout the disease spectrum. An online tool to visualize predicted disease progression was developed to predict relative disability on each subscale per overall disease severity. CONCLUSION: The PSP Rating Scale captures disease severity in both PSP and CBS. Modelling how domains change in relation to one other at varying disease severities may facilitate detection of therapeutic effects in future clinical trials.


Assuntos
Doenças dos Gânglios da Base/fisiopatologia , Progressão da Doença , Doenças Neurodegenerativas/fisiopatologia , Índice de Gravidade de Doença , Paralisia Supranuclear Progressiva/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Doenças dos Gânglios da Base/diagnóstico , Visualização de Dados , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Neurológicos , Doenças Neurodegenerativas/diagnóstico , Prognóstico , Paralisia Supranuclear Progressiva/diagnóstico , Síndrome
16.
Basic Clin Pharmacol Toxicol ; 122(2): 245-252, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28869786

RESUMO

Event-related potentials (ERPs) are commonly used in Neuroscience research, particularly the P3 waveform because it is associated with cognitive brain functions and is easily elicited by auditory or sensory inputs. ERPs are affected by drugs such as lorazepam, which increase the latency and decrease the amplitude of the P3 wave. In this study, auditory-evoked ERPs were generated in 13 older healthy volunteers using an oddball tone paradigm, after administration of single 0.5 and 2 mg doses of lorazepam. Population pharmacokinetics (PK)/pharmacodynamics (PD) models were developed using nonlinear mixed-effects methods in order to assess the effect of lorazepam on the latency and amplitude of the P3 waveforms. The PK/PD models showed that doses of 0.3 mg of lorazepam achieved approximately half of the maximum effect on the latency of the P3 waveform. For P3 amplitude, half the maximum effect was achieved with a dose of 1.2 mg of lorazepam. The PK/PD models also predicted an efficacious dose range of lorazepam, which was close to the recommended therapeutic range. The use of longitudinal P3 latency data allowed better predictions of the lorazepam efficacious dose range than P3 amplitude or aggregate exposure-response data, suggesting that latency could be a more sensitive parameter for drugs with similar mechanisms of action as lorazepam and that time course rather than single time-point ERP data should be collected. Overall, the results suggest that P3 ERP waveforms could be used as potential non-specific biomarkers for functional target engagement for drugs with brain activity, and PK/PD models can aid trial design and choice of doses for development of new drugs with ERP activity.


Assuntos
Córtex Auditivo/efeitos dos fármacos , Potenciais Evocados P300/efeitos dos fármacos , Potenciais Evocados Auditivos/efeitos dos fármacos , Hipnóticos e Sedativos/administração & dosagem , Hipnóticos e Sedativos/farmacocinética , Lorazepam/administração & dosagem , Lorazepam/farmacocinética , Modelos Biológicos , Estimulação Acústica , Córtex Auditivo/fisiologia , Estudos Cross-Over , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Dinâmica não Linear , Tempo de Reação/efeitos dos fármacos , Método Simples-Cego
17.
Psychopharmacology (Berl) ; 235(7): 1875-1886, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29564482

RESUMO

BACKGROUND: Aberrant glutamate neurotransmission, and in particular dysfunction of the N-methyl-D-aspartate receptor (NMDAR), has been implicated in psychiatric disorders and represents a novel therapeutic target. Low-dose administration of the NMDA antagonist ketamine in healthy volunteers elicits a strong blood oxygenation level dependent (BOLD) imaging signal that can be attenuated by pretreatment with single, therapeutically effective doses of marketed medicines interacting with the glutamate system. OBJECTIVE: To test the attenuation of the ketamine-induced BOLD signal by pretreatment with either a metabotropic glutamate receptor (mGluR) 2/3 or a mGluR2 agonist in healthy volunteers METHODS: We used a ketamine challenge pharmacological magnetic resonance imaging (phMRI) paradigm to assess the modulatory effects of single acute doses of LY2140023 (pomaglumetad methionil), the methionine prodrug of the mGluR2/3 agonist LY404039 (10, 40, and 160 mg; N = 16 subjects) and of LY2979165, and the alanine prodrug of the selective orthosteric mGluR2 agonist 2812223 (20 and 60 mg; N = 16 subjects). RESULTS: A reduction in the ketamine-evoked BOLD phMRI signal relative to placebo was observed at the highest doses tested of both LY2140023 and LY2979165. A relationship was observed between reduction of the BOLD signal and increasing plasma levels of 2812223 in the LY2979165 cohort. CONCLUSIONS: These results identify pharmacologically active doses of the group II mGluR agonist prodrugs LY2140023 and LY2979165 in humans. They also extend the classes of compounds that have been experimentally shown to reverse the ketamine-evoked phMRI signal in humans, further supporting the use of this method as a neuroimaging biomarker for assessing functional effects.


Assuntos
Aminoácidos/administração & dosagem , Agonistas de Aminoácidos Excitatórios/administração & dosagem , Ketamina/administração & dosagem , Imageamento por Ressonância Magnética/métodos , Pró-Fármacos/administração & dosagem , Receptores de Glutamato Metabotrópico/agonistas , Administração Oral , Adulto , Estudos de Coortes , Estudos Cross-Over , Método Duplo-Cego , Voluntários Saudáveis , Humanos , Infusões Intravenosas , Ketamina/antagonistas & inibidores , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Adulto Jovem
18.
Environ Microbiol Rep ; 9(2): 79-84, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27888579

RESUMO

Nectar mediates interactions between plants and pollinators in natural and agricultural systems. Specialized microorganisms are common nectar inhabitants, and potentially important mediators of plant-pollinator interactions. However, their diversity and role in mediating pollination services in agricultural systems are poorly characterized. Moreover, agrochemicals are commonly applied to minimize crop damage, but may present ecological consequences for non-target organisms. Assessment of ecological risk has tended to focus on beneficial macroorganisms such as pollinators, with less attention paid to microorganisms. Here, using culture-independent methods, we assess the impact of two widely-used fungicides on nectar microbial community structure in the mass-flowering crop almond (Prunus dulcis). We predicted that fungicide application would reduce fungal richness and diversity, whereas competing bacterial richness would increase, benefitting from negative effects on fungi. We found that fungicides reduced fungal richness and diversity in exposed flowers, but did not significantly affect bacterial richness, diversity, or community composition. The relative abundance of Metschnikowia OTUs, nectar specialists that can impact pollination, was reduced by both fungicides. Given growing recognition of the importance of nectar microorganisms as mediators of plant-pollinator mutualisms, future research should consider the impact of management practices on plant-associated microorganisms and consequences for pollination services in agricultural landscapes.


Assuntos
Biota/efeitos dos fármacos , Flores/microbiologia , Fungos/classificação , Fungos/efeitos dos fármacos , Fungicidas Industriais/metabolismo , Néctar de Plantas , Prunus dulcis/microbiologia , Bactérias/classificação , Bactérias/efeitos dos fármacos , Bactérias/genética , Fungos/genética , Metagenômica , Metschnikowia
19.
Drug Deliv Transl Res ; 7(1): 11-15, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27553192

RESUMO

Intranasally administered regular insulin and insulin aspart have shown cognitive benefit for patients with Alzheimer's disease (AD). To support development of intranasally administered insulin analogs for AD, the central disposition of intranasal insulin lispro in the cerebrospinal fluid (CSF) of healthy volunteers was investigated. Healthy volunteers (N = 8) received two sequential doses of intranasal insulin lispro (48 or 80 IU followed by 160 IU) by Aero Pump in an open-label, single-period study with serial CSF and serum sampling over 5 hours after each dose. CSF insulin lispro was also measured in beagle dogs (N = 6/dose group) that received either 24 IU/kg (equivalent local nasal (IU/cm2) dose to the human 160 IU dose) or 192 IU/kg intranasally, using the same device. Insulin lispro was measured in the CSF and serum using a validated enzyme-linked immunosorbent assay method, and pharmacokinetic parameters were calculated by standard noncompartmental methods. Intranasal administration of insulin lispro was well tolerated. Insulin lispro concentrations in the CSF of humans at all dose levels were below the limit of quantification. Serum insulin lispro concentrations were quantifiable only up to 1-2 hours in the majority of subjects. In contrast to insulin lispro in the CSF of humans, insulin lispro was detectable in the CSF at both dose levels in dogs, and serum concentrations of insulin lispro were generally higher in dogs than in healthy volunteers. The absence of insulin lispro in CSF from healthy volunteers and the lack of robust exposure-response analyses will hinder the development of intranasally administered insulin lispro for AD.


Assuntos
Hipoglicemiantes/líquido cefalorraquidiano , Insulina Lispro/líquido cefalorraquidiano , Administração Intranasal , Animais , Cães , Voluntários Saudáveis , Humanos , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/sangue , Hipoglicemiantes/farmacocinética , Insulina Lispro/administração & dosagem , Insulina Lispro/sangue , Insulina Lispro/farmacocinética , Masculino , Pessoa de Meia-Idade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA