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1.
Proc Natl Acad Sci U S A ; 116(45): 22764-22773, 2019 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-31636194

RESUMO

Neospora caninum, a cyst-forming apicomplexan parasite, is a leading cause of neuromuscular diseases in dogs as well as fetal abortion in cattle worldwide. The importance of the domestic and sylvatic life cycles of Neospora, and the role of vertical transmission in the expansion and transmission of infection in cattle, is not sufficiently understood. To elucidate the population genomics of Neospora, we genotyped 50 isolates collected worldwide from a wide range of hosts using 19 linked and unlinked genetic markers. Phylogenetic analysis and genetic distance indices resolved a single genotype of N. caninum Whole-genome sequencing of 7 isolates from 2 different continents identified high linkage disequilibrium, significant structural variation, but only limited polymorphism genome-wide, with only 5,766 biallelic single nucleotide polymorphisms (SNPs) total. Greater than half of these SNPs (∼3,000) clustered into 6 distinct haploblocks and each block possessed limited allelic diversity (with only 4 to 6 haplotypes resolved at each cluster). Importantly, the alleles at each haploblock had independently segregated across the strains sequenced, supporting a unisexual expansion model that is mosaic at 6 genomic blocks. Integrating seroprevalence data from African cattle, our data support a global selective sweep of a highly inbred livestock pathogen that originated within European dairy stock and expanded transcontinentally via unisexual mating and vertical transmission very recently, likely the result of human activities, including recurrent migration, domestication, and breed development of bovid and canid hosts within similar proximities.


Assuntos
Genoma , Interações Hospedeiro-Parasita , Neospora/genética , Animais , Bovinos , Genótipo , Recombinação Genética
2.
Eur Arch Psychiatry Clin Neurosci ; 270(2): 229-235, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31289926

RESUMO

A recent study reported a negative association between a putatively functional dopamine (DA) polygenic score, indexing higher levels of DA signaling, and depressive symptoms. We attempted to replicate this association using data from the Duke Neurogenetics Study. Our replication attempt was made in a subsample of 520 non-Hispanic Caucasian volunteers (277 women, mean age 19.78 ± 1.24 years). The DA polygenic score was based on the following five loci: rs27072 (SLC6A3/DAT1), rs4532 (DRD1), rs1800497 (DRD2/ANKK1), rs6280 (DRD3), and rs4680 (COMT). Because the discovery sample in the original study consisted mostly of Asian participants, we also conducted a post hoc analysis in a smaller subsample of Asian volunteers (N = 316, 179 women, mean age 19.61 ± 1.32 years). In the primary sample of non-Hispanic Caucasians, a linear regression analysis controlling for sex, age, socioeconomic status (SES), body mass index, genetic ancestry, and both early and recent life stress, revealed that higher DA polygenic scores were associated with higher self-reported symptoms of depression. This was in contrast to the original association of higher DA polygenic scores and lower depressive symptoms. However, the direction of the association in our Asian subsample was consistent with this original finding. Our results also suggested that compared to the Asian subsample, the non-Hispanic Caucasian subsample was characterized by higher SES, lower early and recent life stress, and lower depressive symptoms. These differences may have contributed to the observed divergence in associations. Collectively, the current findings add to evidence that specific genetic associations may differ between populations and further encourage explicit modeling of race/ethnicity in examining the polygenic nature of depressive symptoms and depression.


Assuntos
Povo Asiático/genética , Depressão/genética , Proteínas da Membrana Plasmática de Transporte de Dopamina/genética , Receptores Dopaminérgicos/genética , População Branca/genética , Adolescente , Adulto , Catecol O-Metiltransferase/genética , Feminino , Humanos , Masculino , Herança Multifatorial , Receptores de Dopamina D1/genética , Receptores de Dopamina D2/genética , Receptores de Dopamina D3/genética , Adulto Jovem
3.
Cereb Cortex ; 29(1): 70-76, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29161340

RESUMO

Compared with neural biomarkers of risk for mental illness, little is known about biomarkers of resilience. We explore if greater executive control-related prefrontal activity may function as a resilience biomarker by "rescuing" risk associated with higher threat-related amygdala and lower reward-related ventral striatum activity. Functional MRI was used to assay baseline threat-related amygdala, reward-related ventral striatum, and executive control-related prefrontal activity in 120 young adult volunteers. Participants provided self-reported mood and anxiety ratings at baseline and follow-up. A moderation model revealed a significant three-way interaction wherein higher amygdala and lower ventral striatum activity predicted increases in anxiety in those with average or low but not high prefrontal activity. This effect was specific to anxiety, with the neural biomarkers explaining ~10% of the variance in change over time, above and beyond baseline symptoms, sex, age, IQ, presence or absence of DMS-IV diagnosis, and both early and recent stress. Our findings are consistent with the importance of top-down executive control in adaptive regulation of negative emotions, and highlight a unique combination of neural biomarkers that may identify at-risk individuals for whom the adoption of strategies to improve executive control of negative emotions may prove particularly beneficial.


Assuntos
Ansiedade/diagnóstico por imagem , Ansiedade/psicologia , Função Executiva/fisiologia , Córtex Pré-Frontal/diagnóstico por imagem , Córtex Pré-Frontal/fisiologia , Recompensa , Feminino , Seguimentos , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Fatores de Risco , Inquéritos e Questionários , Adulto Jovem
4.
J Child Psychol Psychiatry ; 60(7): 752-761, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30933355

RESUMO

BACKGROUND: Childhood maltreatment is one of the most potent predictors of future psychopathology, including internalizing disorders. It remains unclear whether heightened amygdala reactivity to threat and elevated stress exposure may be implicated in the pathogenesis and maintenance of internalizing disorders among individuals with a history of childhood maltreatment. METHODS: Using data from a sample of 1,144 young adults, we investigated the contribution of baseline threat-related amygdala reactivity and prospective major stressful life events to internalizing symptoms severity 1 year later (on average) in individuals with a history of maltreatment (n = 100) and propensity score matched nonmaltreated peers (n = 96). RESULTS: Even after stringently matching for several potentially confounding variables - including baseline internalizing symptoms, socioeconomic status and IQ - childhood maltreatment status predicted increased amygdala reactivity at baseline, elevated post-baseline exposure to major stressful life events and internalizing symptoms at follow-up. We also showed, for the first time, that amygdala reactivity at baseline and also post-baseline exposure to major stressful life events mediated the association between a history of maltreatment and future internalizing symptoms. CONCLUSIONS: These findings provide support for the view that maltreatment is a potent developmental insult leading to long-lasting neurocognitive recalibrations of the threat processing system. It is possible that such alterations, over time, may impact mental health functioning by compromising the ability to effectively negotiate everyday challenges (stress susceptibility). These alterations were not, however, found to sensitize an individual to the impact of major stressful life events. The results of this study also lend compelling support to the view that increased psychiatric risk, in the context of childhood maltreatment, follows from an increased propensity to experience major stressful life events (stress generation).


Assuntos
Sobreviventes Adultos de Maus-Tratos Infantis , Tonsila do Cerebelo/fisiopatologia , Sintomas Comportamentais/fisiopatologia , Maus-Tratos Infantis , Estresse Psicológico/fisiopatologia , Adolescente , Adulto , Feminino , Seguimentos , Humanos , Imageamento por Ressonância Magnética , Masculino , Índice de Gravidade de Doença , Adulto Jovem
5.
Aggress Behav ; 45(3): 310-318, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30699245

RESUMO

Amongst a number of negative life sequelae associated with childhood adversity is the later expression of a higher dispositional tendency to experience anger and frustration to a wide range of situations (i.e., trait anger). We recently reported that an association between childhood adversity and trait anger is moderated by individual differences in both threat-related amygdala activity and executive control-related dorsolateral prefrontal cortex (dlPFC) activity, wherein individuals with relatively low amygdala and high dlPFC activity do not express higher trait anger even when having experienced childhood adversity. Here, we examine possible structural correlates of this functional dynamic using diffusion magnetic resonance imaging data from 647 young adult men and women volunteers. Specifically, we tested whether the degree of white matter microstructural integrity as indexed by fractional anisotropy modulated the association between childhood adversity and trait anger. Our analyses revealed that higher microstructural integrity of multiple pathways was associated with an attenuated link between childhood adversity and adult trait anger. Amongst these pathways was the uncinate fasciculus (UF; ΔR 2 = 0.01), which not only provides a major anatomical link between the amygdala and prefrontal cortex but also is associated with individual differences in regulating negative emotion through top-down cognitive reappraisal. These findings suggest that higher microstructural integrity of distributed white matter pathways including but not limited to the UF may represent an anatomical foundation serving to buffer against the expression of childhood adversity as later trait anger, which is itself associated with multiple negative health outcomes.


Assuntos
Adultos Sobreviventes de Eventos Adversos na Infância , Tonsila do Cerebelo/diagnóstico por imagem , Ira/fisiologia , Córtex Pré-Frontal/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Adolescente , Função Executiva/fisiologia , Feminino , Humanos , Individualidade , Masculino , Vias Neurais/diagnóstico por imagem , Personalidade , Adulto Jovem
6.
J Neurosci ; 37(40): 9724-9729, 2017 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-28924013

RESUMO

Sleep disturbances represent one risk factor for depression. Reward-related brain function, particularly the activity of the ventral striatum (VS), has been identified as a potential buffer against stress-related depression. We were therefore interested in testing whether reward-related VS activity would moderate the effect of sleep disturbances on depression in a large cohort of young adults. Data were available from 1129 university students (mean age 19.71 ± 1.25 years; 637 women) who completed a reward-related functional MRI task to assay VS activity and provided self-reports of sleep using the Pittsburgh Sleep Quality Index and symptoms of depression using a summation of the General Distress/Depression and Anhedonic Depression subscales of the Mood and Anxiety Symptoms Questionnaire-short form. Analyses revealed that as VS activity increased the association between sleep disturbances and depressive symptoms decreased. The interaction between sleep disturbances and VS activity was robust to the inclusion of sex, age, race/ethnicity, past or present clinical disorder, early and recent life stress, and anxiety symptoms, as well as the interactions between VS activity and early or recent life stress as covariates. We provide initial evidence that high reward-related VS activity may buffer against depressive symptoms associated with poor sleep. Our analyses help advance an emerging literature supporting the importance of individual differences in reward-related brain function as a potential biomarker of relative risk for depression.SIGNIFICANCE STATEMENT Sleep disturbances are a common risk factor for depression. An emerging literature suggests that reward-related activity of the ventral striatum (VS), a brain region critical for motivation and goal-directed behavior, may buffer against the effect of negative experiences on the development of depression. Using data from a large sample of 1129 university students we demonstrate that as reward-related VS activity increases, the link between sleep disturbances and depression decreases. This finding contributes to accumulating research demonstrating that reward-related brain function may be a useful biomarker of relative risk for depression in the context of negative experiences.


Assuntos
Depressão/fisiopatologia , Recompensa , Transtornos do Sono-Vigília/fisiopatologia , Estriado Ventral/fisiologia , Adolescente , Depressão/diagnóstico por imagem , Depressão/epidemiologia , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Desempenho Psicomotor/fisiologia , Distribuição Aleatória , Autorrelato , Transtornos do Sono-Vigília/diagnóstico por imagem , Transtornos do Sono-Vigília/epidemiologia , Estriado Ventral/diagnóstico por imagem , Adulto Jovem
7.
Psychol Med ; 48(11): 1835-1843, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29248021

RESUMO

BACKGROUND: The experience of childhood maltreatment is a significant risk factor for the development of depression. This risk is particularly heightened after exposure to additional, more contemporaneous stress. While behavioral evidence exists for this relation, little is known about biological correlates of these stress interactions. Identifying such correlates may provide biomarkers of risk for later depression. METHODS: Here, we leverage behavioral, experiential, and neuroimaging data from the Duke Neurogenetics Study to identify potential biomarkers of stress exposure. Based on the past research, we were specifically interested in reward-related connectivity and the interaction of early and more recent stress. We examined psychophysiological interactions between the ventral striatum and other brain regions in relation to these stress variables, as well as measures of internalizing symptomatology (n = 926, participant age range = 18-22 years of age). RESULTS: We found relatively increased reward-related functional connectivity between the left ventral striatum and the medial prefrontal cortex in individuals exposed to greater levels of childhood maltreatment who also experienced greater levels of recent life stress (ß = 0.199, p < 0.005). This pattern of functional connectivity was further associated with elevated symptoms of depression (ß = 0.089, p = 0.006). Furthermore, using a moderated mediation framework, we demonstrate that this functional connectivity provides a biological link between cumulative stress exposure and internalizing symptomatology. CONCLUSIONS: These findings suggest a novel biomarker linking cumulative stress exposure with the later experience of depressive symptoms. Our results are discussed in the context of past research examining stress exposure in relation to depression.


Assuntos
Adultos Sobreviventes de Eventos Adversos na Infância/estatística & dados numéricos , Conectoma/métodos , Depressão/epidemiologia , Córtex Pré-Frontal/fisiopatologia , Recompensa , Estresse Psicológico/epidemiologia , Estriado Ventral/fisiopatologia , Adolescente , Adulto , Biomarcadores , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Córtex Pré-Frontal/diagnóstico por imagem , Estriado Ventral/diagnóstico por imagem , Adulto Jovem
8.
Malar J ; 16(1): 224, 2017 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-28549426

RESUMO

BACKGROUND: Women exposed to Plasmodium infection develop antibodies and become semi-immune. This immunity is suppressed during pregnancy making both the pregnant woman and the foetus vulnerable to the adverse effects of malaria, particularly by Plasmodium falciparum. Intermittent preventive treatment of malaria in pregnancy (IPTp) with Sulfadoxine-pyrimethamine (SP) tablets is one of the current interventions to mitigate the effects of malaria on both the pregnant woman and the unborn child. The extent to which IPTp may interfere with the acquisition of protective immunity against pregnancy-associated malaria (PAM) is undefined in Ghana. METHODS: Three-hundred-and-twenty pregnant women were randomly enrolled at the antenatal clinic (ANC) in Madina, Accra. Venous blood samples were obtained at first ANC registration and at 4-week intervals (post-IPTp administration). Placental and cord blood samples were obtained at delivery and the infants were followed monthly for 6 months after birth. Anti-IgG and IgM antibodies against a crude antigen preparation and the glutamate-rich protein (GLURP) of P. falciparum were quantified by the enzyme-linked immunosorbent assay (ELISA). RESULTS: There was a general decline in the trend of mean concentrations of all the antibodies from enrolment to delivery. The levels of antibodies in cord blood and placenta were well correlated. Children did not show clinical signs of malaria at 6 months after birth. CONCLUSIONS: IgG against both crude antigen and GLURP were present in placenta and cord blood and it is therefore concluded that there is a trend of declining antibody from enrolment to delivery and IPTp-SP may have reduced malaria exposure, however, this does not impact on the transfer of antibodies to the foetus in utero. The levels of maternal and cord blood antibodies at delivery showed no adverse implications on malaria among the children at 6 months. However, the quantum and quality of the antibody transferred needs further investigation to ensure that the infants are protected from severe episodes of malaria.


Assuntos
Anticorpos Antiprotozoários/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Malária Falciparum/imunologia , Plasmodium falciparum/imunologia , Antimaláricos/uso terapêutico , Feminino , Sangue Fetal/imunologia , Gana , Humanos , Lactente , Recém-Nascido , Malária Falciparum/tratamento farmacológico , Malária Falciparum/parasitologia , Placenta/imunologia , Gravidez
9.
Dev Psychopathol ; 27(4 Pt 2): 1611-9, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26535947

RESUMO

The experience of child maltreatment is a significant risk factor for the development of later internalizing disorders such as depression and anxiety. This risk is particularly heightened after exposure to additional, more contemporaneous stress. While behavioral evidence exists for such "stress sensitization," little is known about the mechanisms mediating such relationships, particularly within the brain. Here we report that the experience of child maltreatment independent of recent life stress, gender, and age is associated with reduced structural integrity of the uncinate fasciculus, a major white matter pathway between the amygdala and ventromedial prefrontal cortex, in young adults. We further demonstrate that individuals with lower uncinate fasciculus integrity at baseline who subsequently experience stressful life events report higher levels of internalizing symptomatology at follow-up. Our findings suggest a novel neurobiological mechanism linking child maltreatment with later internalizing symptoms, specifically altered structural connectivity within the brain's threat-detection and emotion-regulation circuitry.


Assuntos
Sintomas Afetivos/fisiopatologia , Ansiedade/fisiopatologia , Maus-Tratos Infantis , Acontecimentos que Mudam a Vida , Substância Branca/patologia , Adolescente , Adulto , Tonsila do Cerebelo/patologia , Feminino , Seguimentos , Humanos , Imageamento por Ressonância Magnética , Masculino , Vias Neurais/patologia , Córtex Pré-Frontal/patologia , Adulto Jovem
10.
Eye (Lond) ; 2023 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-38066111

RESUMO

BACKGROUND: Understanding and mitigating the societal economic impact of vision impairment (VI) is important for achieving the Sustainable Development Goals. AIM: To estimate the prevalent societal economic impact of presenting VI in Trinidad and Tobago using bottom-up cost and utilisation data from the 2014 National Eye Survey of Trinidad and Tobago. METHODS: We took a societal perspective to combine comprehensive, individual-level cost and utilisation data, with population-based prevalence estimates for VI, and additional data from a contemporaneous national eyecare system survey. We included direct (medical and non-medical) and indirect (productivity loss) costs, and intangible losses in total cost estimates, presented in 2014 Trinidad & Tobago (TT) dollars and UK sterling equivalent. We considered but excluded transfer payments and dead weight losses. Sensitivity analyses explored impact on total cost of parameter uncertainty and assumptions. RESULTS: Individual utilisation and cost data were available for 65.5% (n = 2792/4263) and 59.0% (n = 2516/4263) eligible participants aged ≥40 years, respectively. Participant mean age was 58.4(SD 11.8, range 40-103) years, 56.3% were female. We estimated total societal cost of VI in 2014 at UK£365,650,241 (TT$3,842,324,655), equivalent to £675 per capita (population ≥40 years). Loss of wellbeing accounted for 73.3%. Excluding this, the economic cost was UK£97,547,222 (TT$1,025,045,399), of which indirect costs accounted for 70.5%, followed by direct medical costs (17.9%), and direct non-medical costs (11.6%). CONCLUSION: This study provides a comprehensive estimate of the economic impact of vision loss in a Caribbean country, and highlights the extent to which affected individuals and their families bear the societal economic cost of vision impairment.

12.
Mol Genet Metab ; 107(3): 308-14, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22958974

RESUMO

UNLABELLED: We have analyzed pharmacokinetic data for glycerol phenylbutyrate (also GT4P or HPN-100) and sodium phenylbutyrate with respect to possible dosing biomarkers in patients with urea cycle disorders (UCD). STUDY DESIGN: These analyses are based on over 3000 urine and plasma data points from 54 adult and 11 pediatric UCD patients (ages 6-17) who participated in three clinical studies comparing ammonia control and pharmacokinetics during steady state treatment with glycerol phenylbutyrate or sodium phenylbutyrate. All patients received phenylbutyric acid equivalent doses of glycerol phenylbutyrate or sodium phenylbutyrate in a cross over fashion and underwent 24-hour blood samples and urine sampling for phenylbutyric acid, phenylacetic acid and phenylacetylglutamine. RESULTS: Patients received phenylbutyric acid equivalent doses of glycerol phenylbutyrate ranging from 1.5 to 31.8 g/day and of sodium phenylbutyrate ranging from 1.3 to 31.7 g/day. Plasma metabolite levels varied widely, with average fluctuation indices ranging from 1979% to 5690% for phenylbutyric acid, 843% to 3931% for phenylacetic acid, and 881% to 1434% for phenylacetylglutamine. Mean percent recovery of phenylbutyric acid as urinary phenylacetylglutamine was 66.4 and 69.0 for pediatric patients and 68.7 and 71.4 for adult patients on glycerol phenylbutyrate and sodium phenylbutyrate, respectively. The correlation with dose was strongest for urinary phenylacetylglutamine excretion, either as morning spot urine (r = 0.730, p < 0.001) or as total 24-hour excretion (r = 0.791 p<0.001), followed by plasma phenylacetylglutamine AUC(24-hour), plasma phenylacetic acid AUC(24-hour) and phenylbutyric acid AUC(24-hour). Plasma phenylacetic acid levels in adult and pediatric patients did not show a consistent relationship with either urinary phenylacetylglutamine or ammonia control. CONCLUSION: The findings are collectively consistent with substantial yet variable pre-systemic (1st pass) conversion of phenylbutyric acid to phenylacetic acid and/or phenylacetylglutamine. The variability of blood metabolite levels during the day, their weaker correlation with dose, the need for multiple blood samples to capture trough and peak, and the inconsistency between phenylacetic acid and urinary phenylacetylglutamine as a marker of waste nitrogen scavenging limit the utility of plasma levels for therapeutic monitoring. By contrast, 24-hour urinary phenylacetylglutamine and morning spot urine phenylacetylglutamine correlate strongly with dose and appear to be clinically useful non-invasive biomarkers for compliance and therapeutic monitoring.


Assuntos
Amônia/urina , Glutamina/análogos & derivados , Glicerol/análogos & derivados , Fenilacetatos/urina , Fenilbutiratos/urina , Distúrbios Congênitos do Ciclo da Ureia/tratamento farmacológico , Distúrbios Congênitos do Ciclo da Ureia/urina , Adolescente , Adulto , Amônia/sangue , Biomarcadores Farmacológicos/sangue , Biomarcadores Farmacológicos/urina , Criança , Estudos Cross-Over , Esquema de Medicação , Feminino , Glutamina/sangue , Glutamina/urina , Glicerol/sangue , Glicerol/farmacocinética , Glicerol/urina , Humanos , Masculino , Fenilacetatos/sangue , Fenilbutiratos/sangue , Fenilbutiratos/farmacocinética , Distúrbios Congênitos do Ciclo da Ureia/sangue
13.
Malar J ; 11: 372, 2012 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-23140365

RESUMO

The World Health Organization (WHO) convened a malaria vaccines committee (MALVAC) scientific forum from 20 to 21 February 2012 in Geneva, Switzerland, to review the global malaria vaccine portfolio, to gain consensus on approaches to accelerate second-generation malaria vaccine development, and to discuss the need to update the vision and strategic goal of the Malaria Vaccine Technology Roadmap. This article summarizes the forum, which included reviews of leading Plasmodium falciparum vaccine candidates for pre-erythrocytic vaccines, blood-stage vaccines, and transmission-blocking vaccines. Other major topics included vaccine candidates against Plasmodium vivax, clinical trial site capacity development in Africa, trial design considerations for a second-generation malaria vaccine, adjuvant selection, and regulatory oversight functions including vaccine licensure.


Assuntos
Descoberta de Drogas/tendências , Vacinas Antimaláricas/imunologia , Plasmodium falciparum/imunologia , Plasmodium vivax/imunologia , Humanos , Malária Falciparum/prevenção & controle , Malária Vivax/prevenção & controle
14.
Malar J ; 11: 168, 2012 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-22594374

RESUMO

BACKGROUND: In areas mesoendemic for malaria transmission, symptomatic individuals play a significant role as reservoirs for malaria infection. Understanding the pathogenesis of symptomatic malaria is important in devising tools for augmenting malaria control. In this study, the effect of TLR9 polymorphisms on susceptibility to symptomatic malaria was investigated among Ghanaian children. METHODS: Four hundred and twenty nine (429) healthy Ghanaian children, aged three to eleven years (3-11 years), were enrolled into a cohort study and actively followed up for symptomatic malaria for one year. Four TLR9 single nucleotide polymorphisms (SNPs) namely: rs187084 (C-1486 T), rs5743836(C-1237 T), rs352139 (G + 1174A) and rs352140 (G + 2848A) were genotyped by direct sequencing, and their attributable and relative risks for symptomatic malaria determined. TLR9 haplotypes were inferred using the PHASE software and analysed for the risk of symptomatic malaria. A luciferase assay was performed to investigate whether the TLR9 haplotypes influence TLR9 promoter activity. RESULTS: The rs352139 GG genotype showed a significantly increased relative risk of 4.8 for symptomatic malaria (P = 0.0024) and a higher mean parasitaemia (P = 0.04). Conversely, the rs352140 GG genotype showed a significantly reduced relative risk of 0.34 (P = 0.048). TLR9 haplotypes analyses showed that TTAG haplotype was significantly associated with reduced relative risk of 0.2 for symptomatic malaria (P = 4×10⁻6) and a lower mean parasitaemia (0.007), while CTGA haplotype had an increased relative risk of 3.3 (P = 0.005). Functional luciferase reporter gene expression assay revealed that the TTA haplotype had a significantly higher promoter activity than the CCG, CTG and TCG haplotypes. CONCLUSIONS: Taken together, these findings indicate a significant association of TLR9 gene polymorphisms with symptomatic malaria among Ghanaian children in Dangme-West district.


Assuntos
Predisposição Genética para Doença , Malária/genética , Malária/imunologia , Polimorfismo de Nucleotídeo Único , Receptor Toll-Like 9/genética , Criança , Pré-Escolar , Estudos de Coortes , Genótipo , Gana , Haplótipos , Humanos , Estudos Longitudinais , Análise de Sequência de DNA
15.
Malar J ; 11: 253, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-22853732

RESUMO

BACKGROUND: Severe malarial anaemia (SMA) is a major life-threatening complication of paediatric malaria. Protracted production of pro-inflammatory cytokines promoting erythrophagocytosis and depressing erythropoiesis is thought to play an important role in SMA, which is characterized by a high TNF/IL-10 ratio. Whether this TNF/IL-10 imbalance results from an intrinsic incapacity of SMA patients to produce IL-10 or from an IL-10 unresponsiveness to infection is unknown. Monocytes and T cells are recognized as the main sources of TNF and IL-10 in vivo, but little is known about the activation status of those cells in SMA patients. METHODS: The IL-10 and TNF production capacity and the activation phenotype of monocytes and T cells were compared in samples collected from 332 Ghanaian children with non-overlapping SMA (n = 108), cerebral malaria (CM) (n = 144) or uncomplicated malaria (UM) (n = 80) syndromes. Activation status of monocytes and T cells was ascertained by measuring HLA-DR+ and/or CD69+ surface expression by flow cytometry. The TNF and IL-10 production was assessed in a whole-blood assay after or not stimulation with lipopolysaccharide (LPS) or phytohaemaglutinin (PHA) used as surrogate of unspecific monocyte and T cell stimulant. The number of circulating pigmented monocytes was also determined. RESULTS: Monocytes and T cells from SMA and CM patients showed similar activation profiles with a comparable decreased HLA-DR expression on monocytes and increased frequency of CD69+ and HLA-DR+ T cells. In contrast, the acute-phase IL-10 production was markedly decreased in SMA compared to CM (P = .003) and UM (P = .004). Although in SMA the IL-10 response to LPS-stimulation was larger in amplitude than in CM (P = .0082), the absolute levels of IL-10 reached were lower (P = .013). Both the amplitude and levels of TNF produced in response to LPS-stimulation were larger in SMA than CM (P = .019). In response to PHA-stimulation, absolute levels of IL-10 produced in SMA were lower than in CM (P = .005) contrasting with TNF levels, which were higher (P = .001). CONCLUSIONS: These data reveal that SMA patients have the potential to mount efficient IL-10 responses and that the TNF/IL-10 imbalance may reflect a specific monocyte and T cell programming/polarization pattern in response to infection.


Assuntos
Interleucina-10/metabolismo , Malária/imunologia , Malária/patologia , Fator de Necrose Tumoral alfa/metabolismo , Antígenos CD/análise , Antígenos de Diferenciação de Linfócitos T/análise , Criança , Pré-Escolar , Feminino , Citometria de Fluxo , Antígenos HLA-DR/análise , Humanos , Lactente , Lectinas Tipo C/análise , Ativação Linfocitária , Masculino , Monócitos/química , Monócitos/imunologia , Linfócitos T/química , Linfócitos T/imunologia
16.
Tree Physiol ; 42(3): 537-556, 2022 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-34508606

RESUMO

Future climate change predictions for tropical forests highlight increased frequency and intensity of extreme drought events. However, it remains unclear whether large and small trees have differential strategies to tolerate drought due to the different niches they occupy. The future of tropical forests is ultimately dependent on the capacity of small trees (<10 cm in diameter) to adjust their hydraulic system to tolerate drought. To address this question, we evaluated whether the drought tolerance of neotropical small trees can adjust to experimental water stress and was different from tall trees. We measured multiple drought resistance-related hydraulic traits across nine common neotropical genera at the world's longest-running tropical forest throughfall-exclusion experiment and compared their responses with surviving large canopy trees. Small understorey trees in both the control and the throughfall-exclusion treatment had lower minimum stomatal conductance and maximum hydraulic leaf-specific conductivity relative to large trees of the same genera, as well as a greater hydraulic safety margin (HSM), percentage loss of conductivity and embolism resistance, demonstrating that they occupy a distinct hydraulic niche. Surprisingly, in response to the drought treatment, small trees increased specific hydraulic conductivity by 56.3% and leaf:sapwood area ratio by 45.6%. The greater HSM of small understorey trees relative to large canopy trees likely enabled them to adjust other aspects of their hydraulic systems to increase hydraulic conductivity and take advantage of increases in light availability in the understorey resulting from the drought-induced mortality of canopy trees. Our results demonstrate that differences in hydraulic strategies between small understorey and large canopy trees drive hydraulic niche segregation. Small understorey trees can adjust their hydraulic systems in response to changes in water and light availability, indicating that natural regeneration of tropical forests following long-term drought may be possible.


Assuntos
Secas , Árvores , Mudança Climática , Florestas , Folhas de Planta/fisiologia , Árvores/fisiologia
17.
Malar J ; 10: 168, 2011 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-21689436

RESUMO

BACKGROUND: To prepare field sites for malaria vaccine trials, it is important to determine baseline antibody and T cell responses to candidate malaria vaccine antigens. Assessing T cell responses is especially challenging, given genetic restriction, low responses observed in endemic areas, their variability over time, potential suppression by parasitaemia and the intrinsic variability of the assays. METHODS: In Part A of this study, antibody titres were measured in adults from urban and rural communities in Ghana to recombinant Plasmodium falciparum CSP, SSP2/TRAP, LSA1, EXP1, MSP1, MSP3 and EBA175 by ELISA, and to sporozoites and infected erythrocytes by IFA. Positive ELISA responses were determined using two methods. T cell responses to defined CD8 or CD4 T cell epitopes from CSP, SSP2/TRAP, LSA1 and EXP1 were measured by ex vivo IFN-γ ELISpot assays using HLA-matched Class I- and DR-restricted synthetic peptides. In Part B, the reproducibility of the ELISpot assay to CSP and AMA1 was measured by repeating assays of individual samples using peptide pools and low, medium or high stringency criteria for defining positive responses, and by comparing samples collected two weeks apart. RESULTS: In Part A, positive antibody responses varied widely from 17%-100%, according to the antigen and statistical method, with blood stage antigens showing more frequent and higher magnitude responses. ELISA titres were higher in rural subjects, while IFA titres and the frequencies and magnitudes of ex vivo ELISpot activities were similar in both communities. DR-restricted peptides showed stronger responses than Class I-restricted peptides. In Part B, the most stringent statistical criteria gave the fewest, and the least stringent the most positive responses, with reproducibility slightly higher using the least stringent method when assays were repeated. Results varied significantly between the two-week time-points for many participants. CONCLUSIONS: All participants were positive for at least one malaria protein by ELISA, with results dependent on the criteria for positivity. Likewise, ELISpot responses varied among participants, but were relatively reproducible by the three methods tested, especially the least stringent, when assays were repeated. However, results often differed between samples taken two weeks apart, indicating significant biological variability over short intervals.


Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Malária Falciparum/imunologia , Plasmodium falciparum/imunologia , Linfócitos T/imunologia , Adolescente , Adulto , Ensaio de Imunoadsorção Enzimática , ELISPOT , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Gana , Humanos , Interferon gama/metabolismo , Vacinas Antimaláricas/imunologia , Masculino , Pessoa de Meia-Idade , Proteínas Recombinantes/imunologia , Reprodutibilidade dos Testes , População Rural , População Urbana , Adulto Jovem
18.
Int J Geriatr Psychiatry ; 25(11): 1177-85, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20054835

RESUMO

OBJECTIVE: Self-administered by spouses and other collateral informants, the nationally normed Older Adult Behavior Checklist (OABCL) provides standardized data on diverse aspects of older adult psychopathology and adaptive functioning. We tested the validity of the Older Adult Behavior Checklist (OABCL) scale scores in terms of associations with diagnoses of dementia of the Alzheimer's type (DAT) and mood disorders (MD) and with nine measures of psychopathology, cognitive performance, and adaptive functioning. METHOD: Informants completed OABCLs for 727 60-97-year-olds recruited from a memory disorders clinic, geriatric psychiatry clinic, and community-dwelling seniors. OABCL scale scores were tested for associations with DAT and MD diagnoses, as well as with scores on the Neuropsychiatric Inventory, Mini-Mental State Exam (MMSE), Clock Drawing Test, Alzheimer's Disease Assessment Scale, Geriatric Depression Scale, Clinical Dementia Rating, Dementia Severity Rating Scale, Trail Making Test Part A, and Instrumental Activities of Daily Living. RESULTS: OABCL scales had medium to large correlations with the nine other indices of functioning and significantly augmented MMSE discrimination between patients with DAT versus MD. OABCL scales also discriminated significantly between patients diagnosed with DAT versus MD and both these groups versus nonclinical subjects. CONCLUSIONS: Multiple OABCL scales had medium to large associations with diverse indices of functioning based on other kinds of data. The nationally normed OABCL provides new ways to integrate informant and self-report data to improve assessment of older adults. Specifically, the OABCL can provide discrimination between those who qualify for diagnoses of DAT versus MD versus neither diagnosis.


Assuntos
Lista de Checagem , Demência/diagnóstico , Transtornos do Humor/diagnóstico , Escalas de Graduação Psiquiátrica/normas , Adaptação Psicológica , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Lista de Checagem/métodos , Feminino , Avaliação Geriátrica , Humanos , Masculino , Transtornos da Memória/diagnóstico , Transtornos Mentais/diagnóstico , Pessoa de Meia-Idade , Testes Neuropsicológicos , Psicometria , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
19.
Brain Behav ; 10(2): e01493, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31930667

RESUMO

INTRODUCTION: Previous research has identified specific brain regions associated with regulating emotion using common strategies such as expressive suppression and cognitive reappraisal. However, most research focuses on a priori regions and directs participants how to regulate, which may not reflect how people naturally regulate outside the laboratory. METHOD: Here, we used a data-driven approach to investigate how individual differences in distributed intrinsic functional brain connectivity predict emotion regulation tendency outside the laboratory. Specifically, we used connectome-based predictive modeling to extract functional connections in the brain significantly related to the dispositional use of suppression and reappraisal. These edges were then used in a predictive model and cross-validated in novel participants to identify a neural signature that reflects individual differences in the tendency to suppress and reappraise emotion. RESULTS: We found a significant neural signature for the dispositional use of suppression, but not reappraisal. Within this whole-brain signature, the intrinsic connectivity of the default mode network was most informative of suppression tendency. In addition, the predictive performance of this model was significant in males, but not females. CONCLUSION: These findings help inform how whole-brain networks of functional connectivity characterize how people tend to regulate emotion outside the laboratory.


Assuntos
Mapeamento Encefálico , Encéfalo , Conectoma , Regulação Emocional/fisiologia , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Feminino , Neuroimagem Funcional/métodos , Humanos , Individualidade , Masculino , Processos Mentais/fisiologia , Modelos Psicológicos , Fatores Sexuais
20.
Science ; 205(4406): 555-9, 1979 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-17729660

RESUMO

The current interest in locating new or alternative sources of energy has focused attention on solar energy capture by crops that can be subsequently utilized as a substitute for fossil fuels. The very high productivity of sugarepane and the fact that it accumulates sugars that are directly fermentable to alcohol may have caused seemingly less productive crops to be overlooked. We show here that recoverable alcohol from achievable commercial yields of pineapple can actually equal that of sugarcane, with the pineapple crop requiring only a fraction of the water used by sugarcane. Pineapple is well adapted to the subhumid or semiarid tropics and thus is particularly well suited for exploiting large areas not now under cultivation with any crop of commercial value.

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