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1.
Nature ; 608(7921): 93-97, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35794471

RESUMO

Insects, unlike vertebrates, are widely believed to lack male-biased sex steroid hormones1. In the malaria mosquito Anopheles gambiae, the ecdysteroid 20-hydroxyecdysone (20E) appears to have evolved to both control egg development when synthesized by females2 and to induce mating refractoriness when sexually transferred by males3. Because egg development and mating are essential reproductive traits, understanding how Anopheles females integrate these hormonal signals can spur the design of new malaria control programs. Here we reveal that these reproductive functions are regulated by distinct sex steroids through a sophisticated network of ecdysteroid-activating/inactivating enzymes. We identify a male-specific oxidized ecdysteroid, 3-dehydro-20E (3D20E), which safeguards paternity by turning off female sexual receptivity following its sexual transfer and activation by dephosphorylation. Notably, 3D20E transfer also induces expression of a reproductive gene that preserves egg development during Plasmodium infection, ensuring fitness of infected females. Female-derived 20E does not trigger sexual refractoriness but instead licenses oviposition in mated individuals once a 20E-inhibiting kinase is repressed. Identifying this male-specific insect steroid hormone and its roles in regulating female sexual receptivity, fertility and interactions with Plasmodium parasites suggests the possibility for reducing the reproductive success of malaria-transmitting mosquitoes.


Assuntos
Anopheles , Ecdisteroides , Malária , Comportamento Sexual Animal , Animais , Anopheles/enzimologia , Anopheles/parasitologia , Anopheles/fisiologia , Ecdisteroides/biossíntese , Ecdisteroides/metabolismo , Feminino , Fertilidade , Humanos , Malária/parasitologia , Malária/prevenção & controle , Malária/transmissão , Masculino , Mosquitos Vetores/parasitologia , Oviposição , Fosforilação , Plasmodium
2.
PLoS Pathog ; 20(8): e1012052, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39102421

RESUMO

Avian malaria is expanding upslope with warmer temperatures and driving multiple species of Hawaiian birds towards extinction. Methods to reduce malaria transmission are urgently needed to prevent further declines. Releasing Wolbachia-infected incompatible male mosquitoes could suppress mosquito populations and releasing Wolbachia-infected female mosquitoes (or both sexes) could reduce pathogen transmission if the Wolbachia strain reduced vector competence. We cleared Culex quinquefasciatus of their natural Wolbachia pipientis wPip infection and transinfected them with Wolbachia wAlbB isolated from Aedes albopictus. We show that wAlbB infection was transmitted transovarially, and demonstrate cytoplasmic incompatibility with wild-type mosquitoes infected with wPip from Oahu and Maui, Hawaii. We measured vector competence for avian malaria, Plasmodium relictum, lineage GRW4, of seven mosquito lines (two with wAlbB; three with natural wPip infection, and two cleared of Wolbachia infection) by allowing them to feed on canaries infected with recently collected field isolates of Hawaiian P. relictum. We tested 73 groups (Ntotal = 1176) of mosquitoes for P. relictum infection in abdomens and thoraxes 6-14 days after feeding on a range of parasitemias from 0.028% to 2.49%, as well as a smaller subset of salivary glands. We found no measurable effect of Wolbachia on any endpoint, but strong effects of parasitemia, days post feeding, and mosquito strain on both abdomen and thorax infection prevalence. These results suggest that releasing male wAlbB-infected C. quinquefasciatus mosquitoes could suppress wPip-infected mosquito populations, but would have little positive or negative impact on mosquito vector competence for P. relictum if wAlbB became established in local mosquito populations. More broadly, the lack of Wolbachia effects on vector competence we observed highlights the variable impacts of both native and transinfected Wolbachia infections in mosquitoes.


Assuntos
Culex , Malária Aviária , Mosquitos Vetores , Plasmodium , Wolbachia , Animais , Feminino , Masculino , Aedes/microbiologia , Culex/microbiologia , Culex/parasitologia , Havaí , Malária Aviária/transmissão , Mosquitos Vetores/microbiologia , Mosquitos Vetores/parasitologia , Wolbachia/fisiologia
3.
Nature ; 563(7732): 501-507, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30429615

RESUMO

Female Aedes aegypti mosquitoes infect more than 400 million people each year with dangerous viral pathogens including dengue, yellow fever, Zika and chikungunya. Progress in understanding the biology of mosquitoes and developing the tools to fight them has been slowed by the lack of a high-quality genome assembly. Here we combine diverse technologies to produce the markedly improved, fully re-annotated AaegL5 genome assembly, and demonstrate how it accelerates mosquito science. We anchored physical and cytogenetic maps, doubled the number of known chemosensory ionotropic receptors that guide mosquitoes to human hosts and egg-laying sites, provided further insight into the size and composition of the sex-determining M locus, and revealed copy-number variation among glutathione S-transferase genes that are important for insecticide resistance. Using high-resolution quantitative trait locus and population genomic analyses, we mapped new candidates for dengue vector competence and insecticide resistance. AaegL5 will catalyse new biological insights and intervention strategies to fight this deadly disease vector.


Assuntos
Aedes/genética , Infecções por Arbovirus/virologia , Arbovírus , Genoma de Inseto/genética , Genômica/normas , Controle de Insetos , Mosquitos Vetores/genética , Mosquitos Vetores/virologia , Aedes/virologia , Animais , Infecções por Arbovirus/transmissão , Arbovírus/isolamento & purificação , Variações do Número de Cópias de DNA/genética , Vírus da Dengue/isolamento & purificação , Feminino , Variação Genética/genética , Genética Populacional , Glutationa Transferase/genética , Resistência a Inseticidas/efeitos dos fármacos , Masculino , Anotação de Sequência Molecular , Família Multigênica/genética , Piretrinas/farmacologia , Padrões de Referência , Processos de Determinação Sexual/genética
4.
Alzheimers Dement ; 20(5): 3525-3542, 2024 05.
Artigo em Italiano | MEDLINE | ID: mdl-38623902

RESUMO

INTRODUCTION: Effective longitudinal biomarkers that track disease progression are needed to characterize the presymptomatic phase of genetic frontotemporal dementia (FTD). We investigate the utility of cerebral perfusion as one such biomarker in presymptomatic FTD mutation carriers. METHODS: We investigated longitudinal profiles of cerebral perfusion using arterial spin labeling magnetic resonance imaging in 42 C9orf72, 70 GRN, and 31 MAPT presymptomatic carriers and 158 non-carrier controls. Linear mixed effects models assessed perfusion up to 5 years after baseline assessment. RESULTS: Perfusion decline was evident in all three presymptomatic groups in global gray matter. Each group also featured its own regional pattern of hypoperfusion over time, with the left thalamus common to all groups. Frontal lobe regions featured lower perfusion in those who symptomatically converted versus asymptomatic carriers past their expected age of disease onset. DISCUSSION: Cerebral perfusion is a potential biomarker for assessing genetic FTD and its genetic subgroups prior to symptom onset. HIGHLIGHTS: Gray matter perfusion declines in at-risk genetic frontotemporal dementia (FTD). Regional perfusion decline differs between at-risk genetic FTD subgroups . Hypoperfusion in the left thalamus is common across all presymptomatic groups. Converters exhibit greater right frontal hypoperfusion than non-converters past their expected conversion date. Cerebral hypoperfusion is a potential early biomarker of genetic FTD.


Assuntos
Proteína C9orf72 , Circulação Cerebrovascular , Demência Frontotemporal , Imageamento por Ressonância Magnética , Proteínas tau , Humanos , Demência Frontotemporal/genética , Demência Frontotemporal/fisiopatologia , Demência Frontotemporal/diagnóstico por imagem , Feminino , Masculino , Pessoa de Meia-Idade , Estudos Longitudinais , Circulação Cerebrovascular/fisiologia , Circulação Cerebrovascular/genética , Proteína C9orf72/genética , Proteínas tau/genética , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/patologia , Progranulinas/genética , Biomarcadores , Progressão da Doença , Encéfalo/diagnóstico por imagem , Heterozigoto , Mutação , Idoso , Marcadores de Spin , Adulto
5.
PLoS Pathog ; 16(12): e1008908, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33347501

RESUMO

Anopheles mosquitoes have transmitted Plasmodium parasites for millions of years, yet it remains unclear whether they suffer fitness costs to infection. Here we report that the fecundity of virgin and mated females of two important vectors-Anopheles gambiae and Anopheles stephensi-is not affected by infection with Plasmodium falciparum, demonstrating that these human malaria parasites do not inflict this reproductive cost on their natural mosquito hosts. Additionally, parasite development is not impacted by mating status. However, in field studies using different P. falciparum isolates in Anopheles coluzzii, we find that Mating-Induced Stimulator of Oogenesis (MISO), a female reproductive gene strongly induced after mating by the sexual transfer of the steroid hormone 20-hydroxyecdysone (20E), protects females from incurring fecundity costs to infection. MISO-silenced females produce fewer eggs as they become increasingly infected with P. falciparum, while parasite development is not impacted by this gene silencing. Interestingly, previous work had shown that sexual transfer of 20E has specifically evolved in Cellia species of the Anopheles genus, driving the co-adaptation of MISO. Our data therefore suggest that evolution of male-female sexual interactions may have promoted Anopheles tolerance to P. falciparum infection in the Cellia subgenus, which comprises the most important malaria vectors.


Assuntos
Anopheles/genética , Interações Hospedeiro-Parasita/genética , Plasmodium falciparum/genética , Animais , Anopheles/parasitologia , Ecdisterona/genética , Ecdisterona/metabolismo , Feminino , Fertilidade/genética , Expressão Gênica , Hormônios/fisiologia , Malária/parasitologia , Malária Falciparum/parasitologia , Masculino , Mosquitos Vetores/genética , Oogênese , Plasmodium falciparum/patogenicidade , Reprodução/fisiologia
6.
Brain ; 142(4): 1108-1120, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30847466

RESUMO

Genetic forms of frontotemporal dementia are most commonly due to mutations in three genes, C9orf72, GRN or MAPT, with presymptomatic carriers from families representing those at risk. While cerebral blood flow shows differences between frontotemporal dementia and other forms of dementia, there is limited evidence of its utility in presymptomatic stages of frontotemporal dementia. This study aimed to delineate the cerebral blood flow signature of presymptomatic, genetic frontotemporal dementia using a voxel-based approach. In the multicentre GENetic Frontotemporal dementia Initiative (GENFI) study, we investigated cross-sectional differences in arterial spin labelling MRI-based cerebral blood flow between presymptomatic C9orf72, GRN or MAPT mutation carriers (n = 107) and non-carriers (n = 113), using general linear mixed-effects models and voxel-based analyses. Cerebral blood flow within regions of interest derived from this model was then explored to identify differences between individual gene carrier groups and to estimate a timeframe for the expression of these differences. The voxel-based analysis revealed a significant inverse association between cerebral blood flow and the expected age of symptom onset in carriers, but not non-carriers. Regions included the bilateral insulae/orbitofrontal cortices, anterior cingulate/paracingulate gyri, and inferior parietal cortices, as well as the left middle temporal gyrus. For all bilateral regions, associations were greater on the right side. After correction for partial volume effects in a region of interest analysis, the results were found to be largely driven by the C9orf72 genetic subgroup. These cerebral blood flow differences first appeared approximately 12.5 years before the expected symptom onset determined on an individual basis. Cerebral blood flow was lower in presymptomatic mutation carriers closer to and beyond their expected age of symptom onset in key frontotemporal dementia signature regions. These results suggest that arterial spin labelling MRI may be a promising non-invasive imaging biomarker for the presymptomatic stages of genetic frontotemporal dementia.


Assuntos
Circulação Cerebrovascular/genética , Demência Frontotemporal/genética , Adulto , Idoso , Encéfalo/metabolismo , Proteína C9orf72/genética , Estudos Transversais , Feminino , Heterozigoto , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Mutação , Testes Neuropsicológicos , Progranulinas/genética , Proteínas tau/genética
7.
Can J Neurol Sci ; 47(5): 598-603, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32434626

RESUMO

OBJECTIVE: To outline features of the neurologic examination that can be performed virtually through telemedicine platforms (the virtual neurological examination [VNE]), and provide guidance for rapidly pivoting in-person clinical assessments to virtual visits during the COVID-19 pandemic and beyond. METHODS: The full neurologic examination is described with attention to components that can be performed virtually. RESULTS: A screening VNE is outlined that can be performed on a wide variety of patients, along with detailed descriptions of virtual examination maneuvers for specific scenarios (cognitive testing, neuromuscular and movement disorder examinations). CONCLUSIONS: During the COVID-19 pandemic, rapid adoption of virtual medicine will be critical to provide ongoing and timely neurological care. Familiarity and mastery of a VNE will be critical for neurologists, and this article outlines a practical approach to implementation.


Assuntos
Betacoronavirus , Infecções por Coronavirus/terapia , Exame Neurológico/normas , Pneumonia Viral/terapia , Guias de Prática Clínica como Assunto/normas , Telemedicina/normas , Gravação em Vídeo/normas , COVID-19 , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/epidemiologia , Humanos , Exame Neurológico/métodos , Neurologistas/normas , Pandemias , Pneumonia Viral/diagnóstico , Pneumonia Viral/epidemiologia , SARS-CoV-2 , Telemedicina/métodos
8.
PLoS Pathog ; 12(12): e1006060, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27977810

RESUMO

The control of mosquito populations with insecticide treated bed nets and indoor residual sprays remains the cornerstone of malaria reduction and elimination programs. In light of widespread insecticide resistance in mosquitoes, however, alternative strategies for reducing transmission by the mosquito vector are urgently needed, including the identification of safe compounds that affect vectorial capacity via mechanisms that differ from fast-acting insecticides. Here, we show that compounds targeting steroid hormone signaling disrupt multiple biological processes that are key to the ability of mosquitoes to transmit malaria. When an agonist of the steroid hormone 20-hydroxyecdysone (20E) is applied to Anopheles gambiae females, which are the dominant malaria mosquito vector in Sub Saharan Africa, it substantially shortens lifespan, prevents insemination and egg production, and significantly blocks Plasmodium falciparum development, three components that are crucial to malaria transmission. Modeling the impact of these effects on Anopheles population dynamics and Plasmodium transmission predicts that disrupting steroid hormone signaling using 20E agonists would affect malaria transmission to a similar extent as insecticides. Manipulating 20E pathways therefore provides a powerful new approach to tackle malaria transmission by the mosquito vector, particularly in areas affected by the spread of insecticide resistance.


Assuntos
Anopheles/efeitos dos fármacos , Anopheles/parasitologia , Hidrazinas/farmacologia , Inseticidas/farmacologia , Hormônios Juvenis/farmacologia , Malária/transmissão , Controle de Mosquitos/métodos , Animais , Ecdisterona/agonistas , Feminino , Marcação In Situ das Extremidades Cortadas , Insetos Vetores/efeitos dos fármacos , Insetos Vetores/parasitologia , Mosquiteiros Tratados com Inseticida , Estágios do Ciclo de Vida/efeitos dos fármacos , Modelos Teóricos , Dinâmica Populacional
9.
Curr Psychiatry Rep ; 20(3): 16, 2018 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-29527643

RESUMO

PURPOSE OF REVIEW: The purpose of this study was to update a national guideline on assessing drivers with dementia, addressing limitations of previous versions which included a lack of developmental rigor and stakeholder involvement. METHODS: An international multidisciplinary team reviewed 104 different recommendations from 12 previous guidelines on assessing drivers with dementia in light of a recent review of the literature. Revised guideline recommendations were drafted by consensus. A preliminary draft was sent to specialist physician and occupational therapy groups for feedback, using an a priori definition of 90% agreement as consensus. RECENT FINDINGS: The research team drafted 23 guideline recommendations, and responses were received from 145 stakeholders. No recommendation was endorsed by less than 80% of respondents, and 14 (61%) of the recommendations were endorsed by more than 90%.The recommendations are presented in the manuscript. The revised guideline incorporates the perspectives of consensus of an expert group as well as front-line clinicians who regularly assess drivers with dementia. The majority of the recommendations were based on evidence at the level of expert opinion, revealing gaps in the evidence and future directions for research.


Assuntos
Condução de Veículo/psicologia , Demência/diagnóstico , Demência/psicologia , Avaliação Geriátrica/métodos , Internacionalidade , Guias de Prática Clínica como Assunto , Idoso , Idoso de 80 Anos ou mais , Humanos
10.
Am J Geriatr Psychiatry ; 25(12): 1376-1390, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28917504

RESUMO

Guidelines that physicians use to assess fitness to drive for dementia are limited in their currency, applicability, and rigor of development. Therefore, we performed a systematic review to determine the risk of motor vehicle collisions (MVCs) or driving impairment caused by dementia, in order to update international guidelines on driving with dementia. Seven literature databases (MEDLINE, CINAHL, Embase, etc.) were searched for all research studies published after 2004 containing participants with mild, moderate, or severe dementia. From the retrieved 12,860 search results, we included nine studies in this analysis, involving 378 participants with dementia and 416 healthy controls. Two studies reported on self-/informant-reported MVC risk, one revealing a four-fold increase in MVCs per 1,000 miles driven per week in 3 years prior, and the other showing no statistically significant increase over the same time span. We found medium to large effects of dementia on driving abilities in six of the seven recent studies that examined driving impairment. We also found that persons with dementia were much more likely to fail a road test than healthy controls (RR: 10.77, 95% CI: 3.00-38.62, z = 3.65, p < 0.001), with no significant heterogeneity (χ2 = 1.50, p = 0.68, I2 = 0%) in a pooled analysis of four studies. Although the limited data regarding MVCs are equivocal, even mild stages of dementia place patients at a substantially higher risk of failing a performance-based road test and of demonstrating impaired driving abilities on the road.


Assuntos
Acidentes de Trânsito/estatística & dados numéricos , Condução de Veículo/estatística & dados numéricos , Demência/complicações , Demência/epidemiologia , Humanos
11.
Epilepsy Behav ; 68: 11-16, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28109983

RESUMO

BACKGROUND: Adult patients with Down syndrome (DS) are at higher risk of developing Alzheimer-type dementia and epilepsy. The relationship between developing dementia and the risk of developing seizures in DS is poorly characterized to date. In addition, treatment response and medication tolerability have not been rigorously studied. METHODS: We identified 220 patients with a diagnosis of DS and dementia. Those without a history of developing seizures (DD) were compared to patients with new-onset seizures (DD+S) after the age of 35. Electronic records were reviewed for demographics, seizure characteristics, cognitive status, and psychiatric comorbidities. RESULTS: Of the patients included for analysis, twenty-six out of 60 patients had new-onset seizures or developed seizures during the follow-up period (the DD+S group) with a median onset of 2.0years after the dementia diagnosis. Generalized tonic-clonic seizures were the most common seizure type (61.5% of DD+S). Sixteen (61.5%) patients were reported to have myoclonus. Levetiracetam was the most commonly used initial medication, with the majority (73%) of patients treated achieving partial or complete seizure control. The DD+S patients tended to have a similar burden of new-onset neuropsychiatric symptoms compared to the DD group. DISCUSSION: New-onset epilepsy seems to occur early in the course of dementia in DS patients. Patients generally respond to treatment. A great burden of neuropsychiatric symptoms is seen. Future studies need to explore the relationship between ß-amyloid accumulation and epileptiform activity and attend to the care and needs of DS patients with dementia and seizures.


Assuntos
Demência/complicações , Síndrome de Down/complicações , Epilepsia/complicações , Mioclonia/complicações , Adulto , Anticonvulsivantes/uso terapêutico , Progressão da Doença , Epilepsia/tratamento farmacológico , Feminino , Humanos , Levetiracetam , Masculino , Pessoa de Meia-Idade , Mioclonia/tratamento farmacológico , Piracetam/análogos & derivados , Piracetam/uso terapêutico
12.
Proc Natl Acad Sci U S A ; 111(16): 5854-9, 2014 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-24711401

RESUMO

Anopheles gambiae mosquitoes are major African vectors of malaria, a disease that kills more than 600,000 people every year. Given the spread of insecticide resistance in natural mosquito populations, alternative vector control strategies aimed at reducing the reproductive success of mosquitoes are being promoted. Unlike many other insects, An. gambiae females mate a single time in their lives and must use sperm stored in the sperm storage organ, the spermatheca, to fertilize a lifetime's supply of eggs. Maintenance of sperm viability during storage is therefore crucial to the reproductive capacity of these mosquitoes. However, to date, no information is available on the factors and mechanisms ensuring sperm functionality in the spermatheca. Here we identify cellular components and molecular mechanisms used by An. gambiae females to maximize their fertility. Pathways of energy metabolism, cellular transport, and oxidative stress are strongly regulated by mating in the spermatheca. We identify the mating-induced heme peroxidase (HPX) 15 as an important factor in long-term fertility, and demonstrate that its function is required during multiple gonotrophic cycles. We find that HPX15 induction is regulated by sexually transferred 20-hydroxy-ecdysone (20E), a steroid hormone that is produced by the male accessory glands and transferred during copulation, and that expression of this peroxidase is mediated via the 20E nuclear receptor. To our knowledge, our findings provide the first evidence of the mechanisms regulating fertility in Anopheles, and identify HPX15 as a target for vector control.


Assuntos
Estruturas Animais/enzimologia , Anopheles/enzimologia , Proteínas de Insetos/metabolismo , Peroxidase/metabolismo , Comportamento Sexual Animal , Espermatozoides/enzimologia , Estruturas Animais/citologia , Estruturas Animais/efeitos dos fármacos , Estruturas Animais/ultraestrutura , Animais , Anopheles/efeitos dos fármacos , Anopheles/genética , Ecdisona/farmacologia , Ativação Enzimática/efeitos dos fármacos , Feminino , Fertilidade/efeitos dos fármacos , Fertilidade/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Heme/metabolismo , Proteínas de Insetos/genética , Masculino , Peroxidase/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Comportamento Sexual Animal/efeitos dos fármacos , Espermatozoides/citologia , Espermatozoides/efeitos dos fármacos , Espermatozoides/ultraestrutura , Transcrição Gênica/efeitos dos fármacos
13.
Proc Natl Acad Sci U S A ; 111(46): 16353-8, 2014 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-25368171

RESUMO

Female insects generally mate multiple times during their lives. A notable exception is the female malaria mosquito Anopheles gambiae, which after sex loses her susceptibility to further copulation. Sex in this species also renders females competent to lay eggs developed after blood feeding. Despite intense research efforts, the identity of the molecular triggers that cause the postmating switch in females, inducing a permanent refractoriness to further mating and triggering egg-laying, remains elusive. Here we show that the male-transferred steroid hormone 20-hydroxyecdysone (20E) is a key regulator of monandry and oviposition in An. gambiae. When sexual transfer of 20E is impaired by partial inactivation of the hormone and inhibition of its biosynthesis in males, oviposition and refractoriness to further mating in the female are strongly reduced. Conversely, mimicking sexual delivery by injecting 20E into virgin females switches them to an artificial mated status, triggering egg-laying and reducing susceptibility to copulation. Sexual transfer of 20E appears to incapacitate females physically from receiving seminal fluids by a second male. Comparative analysis of microarray data from females after mating and after 20E treatment indicates that 20E-regulated molecular pathways likely are implicated in the postmating switch, including cytoskeleton and musculature-associated genes that may render the atrium impenetrable to additional mates. By revealing signals and pathways shaping key processes in the An. gambiae reproductive biology, our data offer new opportunities for the control of natural populations of malaria vectors.


Assuntos
Anopheles/fisiologia , Ecdisterona/fisiologia , Comportamento Sexual Animal/fisiologia , Animais , Copulação , Ecdisterona/farmacologia , Feminino , Perfilação da Expressão Gênica , Genes de Insetos , Injeções , Insetos Vetores/fisiologia , Malária/transmissão , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Oviposição/fisiologia , Fatores de Tempo , Transcrição Gênica
16.
Mol Ecol ; 24(11): 2656-72, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25865270

RESUMO

Functionally constrained genes are ideal insecticide targets because disruption is often fatal, and resistance mutations are typically costly. Synaptic acetylcholinesterase (AChE) is an essential neurotransmission enzyme targeted by insecticides used increasingly in malaria control. In Anopheles and Culex mosquitoes, a glycine-serine substitution at codon 119 of the Ace-1 gene confers both resistance and fitness costs, especially for 119S/S homozygotes. G119S in Anopheles gambiae from Accra (Ghana) is strongly associated with resistance, and, despite expectations of cost, resistant 119S alleles are increasing significantly in frequency. Sequencing of Accra females detected only a single Ace-1 119S haplotype, whereas 119G diversity was high overall but very low at non-synonymous sites, evidence of strong purifying selection driven by functional constraint. Flanking microsatellites showed reduced diversity, elevated linkage disequilibrium and high differentiation of 119S, relative to 119G homozygotes across up to two megabases of the genome. Yet these signals of selection were inconsistent and sometimes weak tens of kilobases from Ace-1. This unexpected finding is attributable to apparently ubiquitous amplification of 119S alleles as part of a large copy number variant (CNV) far exceeding the size of the Ace-1 gene, whereas 119G alleles were unduplicated. Ace-1 CNV was detectable in archived samples collected when the 119S allele was rare in Ghana. Multicopy amplification of resistant alleles has not been observed previously and is likely to underpin the recent increase in 119S frequency. The large CNV compromised localization of the strong selective sweep around Ace-1, emphasizing the need to integrate CNV analysis into genome scans for selection.


Assuntos
Acetilcolinesterase/genética , Anopheles/genética , Variações do Número de Cópias de DNA , Evolução Molecular , Resistência a Inseticidas/genética , Alelos , Animais , Anopheles/enzimologia , Feminino , Genes de Insetos , Genótipo , Gana , Haplótipos , Desequilíbrio de Ligação , Repetições de Microssatélites , Dados de Sequência Molecular , Análise de Sequência de DNA
17.
Proc Natl Acad Sci U S A ; 109(16): 6147-52, 2012 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-22460795

RESUMO

In the last decade there have been marked reductions in malaria incidence in sub-Saharan Africa. Sustaining these reductions will rely upon insecticides to control the mosquito malaria vectors. We report that in the primary African malaria vector, Anopheles gambiae sensu stricto, a single enzyme, CYP6M2, confers resistance to two classes of insecticide. This is unique evidence in a disease vector of cross-resistance associated with a single metabolic gene that simultaneously reduces the efficacy of two of the four classes of insecticide routinely used for malaria control. The gene-expression profile of a highly DDT-resistant population of A. gambiae s.s. from Ghana was characterized using a unique whole-genome microarray. A number of genes were significantly overexpressed compared with two susceptible West African colonies, including genes from metabolic families previously linked to insecticide resistance. One of the most significantly overexpressed probe groups (false-discovery rate-adjusted P < 0.0001) belonged to the cytochrome P450 gene CYP6M2. This gene is associated with pyrethroid resistance in wild A. gambiae s.s. populations) and can metabolize both type I and type II pyrethroids in recombinant protein assays. Using in vitro assays we show that recombinant CYP6M2 is also capable of metabolizing the organochlorine insecticide DDT in the presence of solubilizing factor sodium cholate.


Assuntos
Anopheles/genética , Sistema Enzimático do Citocromo P-450/genética , Proteínas de Insetos/genética , Resistência a Inseticidas/genética , Animais , Anopheles/crescimento & desenvolvimento , Cromatografia Líquida de Alta Pressão , Sistema Enzimático do Citocromo P-450/metabolismo , DDT/metabolismo , DDT/farmacologia , Feminino , Perfilação da Expressão Gênica , Gana , Humanos , Proteínas de Insetos/metabolismo , Insetos Vetores/efeitos dos fármacos , Insetos Vetores/genética , Insetos Vetores/crescimento & desenvolvimento , Inseticidas/classificação , Inseticidas/metabolismo , Inseticidas/farmacologia , Malária/prevenção & controle , Controle de Mosquitos/métodos , Análise de Sequência com Séries de Oligonucleotídeos , Piretrinas/metabolismo , Piretrinas/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa
18.
Neurol Clin Pract ; 14(6): e200339, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-39185101

RESUMO

Background and Objectives: The COVID-19 pandemic forced a shift to virtual care in several neurologic care settings. Little is known about the validity of the virtual neurologic examination (VNE) for clinical decision making when compared with the in-person neurologic examination (IPNE). The objective of this study was to investigate the utility of the VNE in arriving at an accurate localization and diagnosis in comparison with the traditional IPNE in an ambulatory outpatient setting. Methods: A retrospective chart review of patients examined virtually and in-person within 4 months at outpatient general neurology and neuromuscular clinics from 2 tertiary academic care centers during the COVID-19 pandemic was conducted. The Cohen kappa coefficient was calculated to test agreement between virtual and in-person assessment results, and descriptive statistical methods were used to compare accuracy, localization, and diagnosis. Results: A total of 81 patients met the inclusion criteria. Overall, there was fair agreement between VNE and IPNE (64% agreement, p = 0.003). Substantial agreement between VNE and IPNE was observed for gait abnormalities; moderate agreement for extraocular movements, facial weakness, dysarthria, fasciculation, and lower limb weakness; and fair agreement for bulk, upper limb weakness, and sensation. No agreement between VNE and IPNE was seen for hypokinetic or hyperkinetic movements and cerebellar signs. Compared with the IPNE, specificity of the VNE was 86% and sensitivity was 56%. Some cases demonstrated a consistent localization (44%) and diagnosis (57%) after virtual and in-person assessments. The localization was changed in 15% and refined in 41% of cases between visits. The diagnosis was changed in 14% and refined in 30% of cases. Discussion: The high rates of agreement in detecting an abnormality on the VNE and IPNE for some maneuvers and resultant clinical impressions may support the validity of the VNE for initial consultation depending on the clinical scenario. The VNE seems to be a good surrogate evaluation compared with the IPNE for certain chief complaints. The low sensitivity suggests that a normal VNE should warrant further in-person clinical correlation, especially in the context of a highly concerning history. The IPNE is more sensitive in detecting subtle abnormalities on examination, and a low threshold should be used to bring a patient in for an IPNE if the VNE is normal in certain clinical contexts.

19.
Biol Psychiatry ; 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38866174

RESUMO

BACKGROUND: Increased vulnerability to stress is a major risk factor for several mood disorders, including major depressive disorder. Although cellular and molecular mechanisms associated with depressive behaviors following stress have been identified, little is known about the mechanisms that confer the vulnerability that predisposes individuals to future damage from chronic stress. METHODS: We used multisite in vivo neurophysiology in freely behaving male and female C57BL/6 mice (n = 12) to measure electrical brain network activity previously identified as indicating a latent stress vulnerability brain state. We combined this neurophysiological approach with single-cell RNA sequencing of the prefrontal cortex to identify distinct transcriptomic differences between groups of mice with inherent high and low stress vulnerability. RESULTS: We identified hundreds of differentially expressed genes (padjusted < .05) across 5 major cell types in animals with high and low stress vulnerability brain network activity. This unique analysis revealed that GABAergic (gamma-aminobutyric acidergic) neuron gene expression contributed most to the network activity of the stress vulnerability brain state. Upregulation of mitochondrial and metabolic pathways also distinguished high and low vulnerability brain states, especially in inhibitory neurons. Importantly, genes that were differentially regulated with vulnerability network activity significantly overlapped (above chance) with those identified by genome-wide association studies as having single nucleotide polymorphisms significantly associated with depression as well as genes more highly expressed in postmortem prefrontal cortex of patients with major depressive disorder. CONCLUSIONS: This is the first study to identify cell types and genes involved in a latent stress vulnerability state in the brain.

20.
BJPsych Open ; 9(3): e92, 2023 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-37227080

RESUMO

BACKGROUND: Current assessment and management models often do not adequately address the many aspects of managing complex brain disorders involving disordered affect, behaviour and cognition (ABC). A more collaborative model of care, where several specialties can jointly assess and manage patients with complex brain disorders, is gaining attention. AIMS: In this case report, we present two cases that highlight the benefits of the 'brain medicine' clinical model. METHOD: The Brain Medicine Clinic employs an integrated clinical model in which psychiatrists and neurologists provide integrated interdisciplinary assessments of patients with complex brain disorders, leading to comprehensive assessment. We describe the clinical model and the trajectories of two patients with complex brain disorders seen in this clinic. In these case descriptions, we explain how the brain medicine clinical approach leads to an improved patient experience. RESULTS: The Brain Medicine Clinic assessments resulted in a neurobiopsychosocial formulation of symptoms and, consequently, holistic individualised treatment plans for two patients with complex brain disorders. This approach to patients' conditions emerges from the understanding that there are multifactorial causes of brain disorders at the social, cultural, psychological and biological level. CONCLUSIONS: Integrated interdisciplinary assessments allow for tailored treatment plans for individuals experiencing complex brain disorders, while creating efficiencies for the patient and the healthcare system.

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