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1.
Andrology ; 8(1): 82-90, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31001931

RESUMO

BACKGROUND: We have shown that testosterone administration suppresses hepcidin, stimulates iron-dependent erythropoiesis, and increases hemoglobin and hematocrit. OBJECTIVE: We investigated whether testosterone-mediated suppression of hepcidin plays an essential role in mediating testosterone's stimulatory effects on erythropoiesis. METHODS: We utilized two mouse models to elucidate the role of hepcidin as a mediator of testosterone's effects on erythropoiesis: First, we used a whole-body hepcidin knockout (HepKO) mouse. Because testosterone's effects on hepcidin expression are mediated through androgen receptor, we also utilized a liver-specific androgen receptor knockout mouse (L-ArKO). Effects of 6 weeks of testosterone (50 mg/kg weekly) administration relative to vehicle on hemoglobin and hematocrit, red blood cell indices, and markers of iron stores and availability were compared between wild-type (WT) and the two genetically modified mouse models. RESULTS: HepKO mice had significantly higher baseline levels of hemoglobin, hematocrit, serum and liver iron, and ferritin than WT mice. Compared to vehicle group, testosterone administration was associated with significant increases in hematocrit, hemoglobin, red cell counts, reticulocyte count, reticulocyte hemoglobin, and serum iron levels in both HepKO and WT mice. Baseline hematocrit levels did not differ between WT and L-ArKO mice. Compared to vehicle, testosterone treatment was associated with significantly greater increase in hematocrit, hemoglobin, red cell count, reticulocyte count, reticulocyte hemoglobin, and serum iron in WT and L-ArKO mice. CONCLUSION: Although hepcidin suppression by testosterone increases iron availability and erythropoiesis, hepcidin suppression is not essential for mediating testosterone's effects on erythropoiesis in healthy mice.


Assuntos
Eritropoese/efeitos dos fármacos , Hepatócitos/metabolismo , Hepcidinas/metabolismo , Receptores Androgênicos/metabolismo , Testosterona/farmacologia , Animais , Feminino , Hepcidinas/genética , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout
2.
Water Res ; 157: 356-364, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30970285

RESUMO

Enteric viruses pose the greatest acute human health risks associated with subsurface drinking water supplies, yet quantitative risk assessment tools have rarely been used to develop health-based targets for virus treatment in drinking water sourced from these supplies. Such efforts have previously been hampered by a lack of consensus concerning a suitable viral reference pathogen and dose-response model as well as difficulties in quantifying pathogenic viruses in water. A reverse quantitative microbial risk assessment (QMRA) framework and quantitative polymerase chain reaction data for norovirus genogroup I in subsurface drinking water supplies were used herein to evaluate treatment needs for such water supplies. Norovirus was not detected in over 90% of samples, which emphasizes the need to consider the spatially and/or temporally intermittent patterns of enteric pathogen contamination in subsurface water supplies. Collectively, this analysis reinforces existing recommendations that a minimum 4-log treatment goal is needed for enteric viruses in groundwater in absence of well-specific monitoring information. This result is sensitive to the virus dose-response model used as there is approximately a 3-log discrepancy among virus dose-response models in the existing literature. This emphasizes the need to address the uncertainties and lack of consensus related to various QMRA modelling approaches and the analytical limitations that preclude more accurate description of virus risks.


Assuntos
Água Potável , Água Subterrânea , Vírus , Desinfecção , Humanos , Microbiologia da Água , Abastecimento de Água
3.
Mol Psychiatry ; 23(4): 1066-1075, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-28416813

RESUMO

Preclinical evidence suggests that the actions of ovarian steroid hormones and brain-derived neurotrophic factor (BDNF) are highly convergent on brain function. Studies in humanized mice document an interaction between estrus cycle-related changes in estradiol secretion and BDNF Val66Met genotype on measures of hippocampal function and anxiety-like behavior. We believe our multimodal imaging data provide the first demonstration in women that the effects of the BDNF Val/Met polymorphism on hippocampal function are selectively modulated by estradiol. In a 6-month pharmacological hormone manipulation protocol, healthy, regularly menstruating, asymptomatic women completed positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) scans while performing the n-back working memory task during three hormone conditions: ovarian suppression induced by the gonadotropin-releasing hormone agonist, leuprolide acetate; leuprolide plus estradiol; and leuprolide plus progesterone. For each of the three hormone conditions, a discovery data set was obtained with oxygen-15 water regional cerebral blood flow PET in 39 healthy women genotyped for BDNF Val66Met, and a confirmatory data set was obtained with fMRI in 27 women. Our results, in close agreement across the two imaging platforms, demonstrate an ovarian hormone-by-BDNF interaction on working memory-related hippocampal function (PET: F2,37=9.11, P=0.00026 uncorrected, P=0.05, familywise error corrected with small volume correction; fMRI: F2,25=5.43, P=0.01, uncorrected) that reflects differential hippocampal recruitment in Met carriers but only in the presence of estradiol. These findings have clinical relevance for understanding the neurobiological basis of individual differences in the cognitive and behavioral effects of ovarian steroids in women, and may provide a neurogenetic framework for understanding neuropsychiatric disorders related to reproductive hormones as well as illnesses with sex differences in disease expression and course.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Hormônios Esteroides Gonadais/metabolismo , Hipocampo/metabolismo , Memória de Curto Prazo/fisiologia , Adulto , Circulação Cerebrovascular , Método Duplo-Cego , Estradiol/administração & dosagem , Estradiol/sangue , Feminino , Hipocampo/diagnóstico por imagem , Humanos , Leuprolida/farmacologia , Imageamento por Ressonância Magnética , Metionina/genética , Pessoa de Meia-Idade , Imagem Multimodal/métodos , Neuroimagem/métodos , Testes Neuropsicológicos , Ovário/metabolismo , Polimorfismo de Nucleotídeo Único , Tomografia por Emissão de Pósitrons , Progesterona/administração & dosagem , Progesterona/sangue , Distribuição Aleatória , Supositórios , Valina/genética
4.
Transl Psychiatry ; 7(8): e1193, 2017 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-28786978

RESUMO

Clinical evidence suggests that symptoms in premenstrual dysphoric disorder (PMDD) reflect abnormal responsivity to ovarian steroids. This differential steroid sensitivity could be underpinned by abnormal processing of the steroid signal. We used a pharmacometabolomics approach in women with prospectively confirmed PMDD (n=15) and controls without menstrual cycle-related affective symptoms (n=15). All were medication-free with normal menstrual cycle lengths. Notably, women with PMDD were required to show hormone sensitivity in an ovarian suppression protocol. Ovarian suppression was induced for 6 months with gonadotropin-releasing hormone (GnRH)-agonist (Lupron); after 3 months all were randomized to 4 weeks of estradiol (E2) or progesterone (P4). After a 2-week washout, a crossover was performed. Liquid chromatography/tandem mass spectrometry measured 49 steroid metabolites in serum. Values were excluded if >40% were below the limit of detectability (n=21). Analyses were performed with Wilcoxon rank-sum tests using false-discovery rate (q<0.2) for multiple comparisons. PMDD and controls had similar basal levels of metabolites during Lupron and P4-derived neurosteroids during Lupron or E2/P4 conditions. Both groups had significant increases in several steroid metabolites compared with the Lupron alone condition after treatment with E2 (that is, estrone-SO4 (q=0.039 and q=0.002, respectively) and estradiol-3-SO4 (q=0.166 and q=0.001, respectively)) and after treatment with P4 (that is, allopregnanolone (q=0.001 for both PMDD and controls), pregnanediol (q=0.077 and q=0.030, respectively) and cortexone (q=0.118 and q=0.157, respectively). Only sulfated steroid metabolites showed significant diagnosis-related differences. During Lupron plus E2 treatment, women with PMDD had a significantly attenuated increase in E2-3-sulfate (q=0.035) compared with control women, and during Lupron plus P4 treatment a decrease in DHEA-sulfate (q=0.07) compared with an increase in controls. Significant effects of E2 addback compared with Lupron were observed in women with PMDD who had significant decreases in DHEA-sulfate (q=0.065) and pregnenolone sulfate (q=0.076), whereas controls had nonsignificant increases (however, these differences did not meet statistical significance for a between diagnosis effect). Alterations of sulfotransferase activity could contribute to the differential steroid sensitivity in PMDD. Importantly, no differences in the formation of P4-derived neurosteroids were observed in this otherwise highly selected sample of women studied under controlled hormone exposures.


Assuntos
Estradiol/farmacologia , Leuprolida/farmacologia , Metaboloma/efeitos dos fármacos , Transtorno Disfórico Pré-Menstrual/metabolismo , Progesterona/farmacologia , Adulto , Estudos Cross-Over , Desoxicorticosterona/sangue , Estradiol/análogos & derivados , Estradiol/sangue , Estrona/sangue , Feminino , Humanos , Pessoa de Meia-Idade , Pregnanodiol/sangue , Pregnanolona/sangue , Adulto Jovem
5.
Mol Psychiatry ; 22(8): 1172-1184, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28044059

RESUMO

Clinical evidence suggests that mood and behavioral symptoms in premenstrual dysphoric disorder (PMDD), a common, recently recognized, psychiatric condition among women, reflect abnormal responsivity to ovarian steroids. This differential sensitivity could be due to an unrecognized aspect of hormonal signaling or a difference in cellular response. In this study, lymphoblastoid cell line cultures (LCLs) from women with PMDD and asymptomatic controls were compared via whole-transcriptome sequencing (RNA-seq) during untreated (ovarian steroid-free) conditions and following hormone treatment. The women with PMDD manifested ovarian steroid-triggered behavioral sensitivity during a hormone suppression and addback clinical trial, and controls did not, leading us to hypothesize that women with PMDD might differ in their cellular response to ovarian steroids. In untreated LCLs, our results overall suggest a divergence between mRNA (for example, gene transcription) and protein (for example, RNA translation in proteins) for the same genes. Pathway analysis of the LCL transcriptome revealed, among others, over-expression of ESC/E(Z) complex genes (an ovarian steroid-regulated gene silencing complex) in untreated LCLs from women with PMDD, with more than half of these genes over-expressed as compared with the controls, and with significant effects for MTF2, PHF19 and SIRT1 (P<0.05). RNA and protein expression of the 13 ESC/E(Z) complex genes were individually quantitated. This pattern of increased ESC/E(Z) mRNA expression was confirmed in a larger cohort by qRT-PCR. In contrast, protein expression of ESC/E(Z) genes was decreased in untreated PMDD LCLs with MTF2, PHF19 and SIRT1 all significantly decreased (P<0.05). Finally, mRNA expression of several ESC/E(Z) complex genes were increased by progesterone in controls only, and decreased by estradiol in PMDD LCLs. These findings demonstrate that LCLs from women with PMDD manifest a cellular difference in ESC/E(Z) complex function both in the untreated condition and in response to ovarian hormones. Dysregulation of ESC/E(Z) complex function could contribute to PMDD.


Assuntos
Transtorno Disfórico Pré-Menstrual/genética , Transtorno Disfórico Pré-Menstrual/metabolismo , Proteínas Repressoras/metabolismo , Adulto , Afeto/fisiologia , Linhagem Celular , Estradiol , Feminino , Regulação da Expressão Gênica/genética , Inativação Gênica/fisiologia , Humanos , Ovário/metabolismo , Progesterona , Proteínas Repressoras/genética , Esteroides/metabolismo , Transcriptoma/genética , Regulação para Cima
6.
Psychol Med ; 47(5): 787-799, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27866476

RESUMO

BACKGROUND: Universal screening for postpartum depression is recommended in many countries. Knowledge of whether the disclosure of depressive symptoms in the postpartum period differs across cultures could improve detection and provide new insights into the pathogenesis. Moreover, it is a necessary step to evaluate the universal use of screening instruments in research and clinical practice. In the current study we sought to assess whether the Edinburgh Postnatal Depression Scale (EPDS), the most widely used screening tool for postpartum depression, measures the same underlying construct across cultural groups in a large international dataset. METHOD: Ordinal regression and measurement invariance were used to explore the association between culture, operationalized as education, ethnicity/race and continent, and endorsement of depressive symptoms using the EPDS on 8209 new mothers from Europe and the USA. RESULTS: Education, but not ethnicity/race, influenced the reporting of postpartum depression [difference between robust comparative fit indexes (∆*CFI) 0.01), but not between European countries (∆*CFI < 0.01). CONCLUSIONS: Investigators and clinicians should be aware of the potential differences in expression of phenotype of postpartum depression that women of different educational backgrounds may manifest. The increasing cultural heterogeneity of societies together with the tendency towards globalization requires a culturally sensitive approach to patients, research and policies, that takes into account, beyond rhetoric, the context of a person's experiences and the context in which the research is conducted.


Assuntos
Comparação Transcultural , Depressão Pós-Parto/diagnóstico , Depressão Pós-Parto/etnologia , Escalas de Graduação Psiquiátrica , Autorrelato , Adolescente , Adulto , Feminino , Humanos , Pessoa de Meia-Idade , Adulto Jovem
7.
Water Res ; 105: 625-637, 2016 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-27721171

RESUMO

Many Cryptosporidium species/genotypes are not considered infectious to humans, and more realistic estimations of seasonal infection risks could be made using human infectious species/genotype information to inform quantitative microbial risk assessments (QMRA). Cryptosporidium oocyst concentration and species/genotype data were collected from three surface water surveillance programs in two river basins [South Nation River, SN (2004-09) and Grand River, GR (2005-13)] in Ontario, Canada to evaluate seasonal infection risks. Main river stems, tributaries, agricultural drainage streams, water treatment plant intakes, and waste water treatment plant effluent impacted sites were sampled. The QMRA employed two sets of exposure data to compute risk: one assuming all observed oocysts were infectious to humans, and the other based on the fraction of oocysts that were C. hominis and/or C. parvum (dominant human infectious forms of the parasite). Viability was not considered and relative infection risk was evaluated using a single hypothetical recreational exposure. Many sample site groupings for both river systems, had significant seasonality in Cryptosporidium occurrence and concentrations (p ≤ 0.05); occurrence and concentrations were generally highest in autumn for SN, and autumn and summer for GR. Mean risk values (probability of infection per exposure) for all sites combined, for each river system, were roughly an order of magnitude lower (avg. of SN and GR 5.3 × 10-5) when considering just C. parvum and C. hominis oocysts, in relation to mean infection risk (per exposure) assuming all oocysts were infectious to humans (5.5 × 10-4). Seasonality in mean risk (targeted human infectious oocysts only) was most strongly evident in SN (e.g., 7.9 × 10-6 in spring and 8.1 × 10-5 in summer). Such differences are important if QMRA is used to quantify effects of water safety/quality management practices where inputs from a vast array of fecal pollution sources can readily occur. Cryptosporidium seasonality in water appears to match the seasonality of human infections from Cryptosporidium in the study regions. This study highlights the importance of Cryptosporidium species/genotype data to help determine surface water pollution sources and seasonality, as well as to help more accurately quantify human infection risks by the parasite.


Assuntos
Cryptosporidium/genética , Estações do Ano , Animais , Criptosporidiose/epidemiologia , Genótipo , Humanos , Oocistos
8.
Epidemiol Infect ; 144(7): 1355-70, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26564479

RESUMO

Waterborne illness related to the consumption of contaminated or inadequately treated water is a global public health concern. Although the magnitude of drinking water-related illnesses in developed countries is lower than that observed in developing regions of the world, drinking water is still responsible for a proportion of all cases of acute gastrointestinal illness (AGI) in Canada. The estimated burden of endemic AGI in Canada is 20·5 million cases annually - this estimate accounts for under-reporting and under-diagnosis. About 4 million of these cases are domestically acquired and foodborne, yet the proportion of waterborne cases is unknown. There is evidence that individuals served by private systems and small community systems may be more at risk of waterborne illness than those served by municipal drinking water systems in Canada. However, little is known regarding the contribution of these systems to the overall drinking water-related AGI burden in Canada. Private water supplies serve an estimated 12% of the Canadian population, or ~4·1 million people. An estimated 1·4 million (4·1%) people in Canada are served by small groundwater (2·6%) and surface water (1·5%) supplies. The objective of this research is to estimate the number of AGI cases attributable to water consumption from these supplies in Canada using a quantitative microbial risk assessment (QMRA) approach. This provides a framework for others to develop burden of waterborne illness estimates for small water supplies. A multi-pathogen QMRA of Giardia, Cryptosporidium, Campylobacter, E. coli O157 and norovirus, chosen as index waterborne pathogens, for various source water and treatment combinations was performed. It is estimated that 103 230 AGI cases per year are due to the presence of these five pathogens in drinking water from private and small community water systems in Canada. In addition to providing a mechanism to assess the potential burden of AGI attributed to small systems and private well water in Canada, this research supports the use of QMRA as an effective source attribution tool when there is a lack of randomized controlled trial data to evaluate the public health risk of an exposure source. QMRA is also a powerful tool for identifying existing knowledge gaps on the national scale to inform future surveillance and research efforts.


Assuntos
Água Potável/microbiologia , Água Potável/parasitologia , Gastroenteropatias/epidemiologia , Água Subterrânea/microbiologia , Água Subterrânea/parasitologia , Vigilância da População/métodos , Doença Aguda , Canadá/epidemiologia , Água Potável/virologia , Gastroenteropatias/microbiologia , Gastroenteropatias/parasitologia , Água Subterrânea/virologia , Humanos , Medição de Risco , Abastecimento de Água/normas
9.
Oncogene ; 34(16): 2115-24, 2015 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-24909164

RESUMO

Iron metabolism is essential for many cellular processes, including oxygen transport, respiration and DNA synthesis, and many cancer cells exhibit dysregulation in iron metabolism. Maintenance of cellular iron homeostasis is regulated by iron regulatory proteins (IRPs), which control the expression of iron-related genes by binding iron-responsive elements (IREs) of target mRNAs. Here, we report that mitochondrial SIRT3 regulates cellular iron metabolism by modulating IRP1 activity. SIRT3 loss increases reactive oxygen species production, leading to elevated IRP1 binding to IREs. As a consequence, IRP1 target genes, such as the transferrin receptor (TfR1), a membrane-associated glycoprotein critical for iron uptake and cell proliferation, are controlled by SIRT3. Importantly, SIRT3 deficiency results in a defect in cellular iron homeostasis. SIRT3 null cells contain high levels of iron and lose iron-dependent TfR1 regulation. Moreover, SIRT3 null mice exhibit higher levels of iron and TfR1 expression in the pancreas. We found that the regulation of iron uptake and TfR1 expression contribute to the tumor-suppressive activity of SIRT3. Indeed, SIRT3 expression is negatively correlated with TfR1 expression in human pancreatic cancers. SIRT3 overexpression decreases TfR1 expression by inhibiting IRP1 and represses proliferation in pancreatic cancer cells. Our data uncover a novel role of SIRT3 in cellular iron metabolism through IRP1 regulation and suggest that SIRT3 functions as a tumor suppressor, in part, by modulating cellular iron metabolism.


Assuntos
Antígenos CD/metabolismo , Proteína 1 Reguladora do Ferro/antagonistas & inibidores , Ferro/metabolismo , Neoplasias Pancreáticas/patologia , Receptores da Transferrina/metabolismo , Sirtuína 3/metabolismo , Animais , Antígenos CD/biossíntese , Transporte Biológico , Linhagem Celular Tumoral , Proliferação de Células/genética , Humanos , Proteína 1 Reguladora do Ferro/biossíntese , Camundongos , Camundongos Knockout , Mitocôndrias/metabolismo , Pâncreas/metabolismo , Receptores da Transferrina/biossíntese , Sirtuína 3/genética
10.
Water Res ; 55: 203-14, 2014 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-24607316

RESUMO

Concentrations of particular types of microorganisms are commonly measured in various waters, yet the accuracy and precision of reported microorganism concentration values are often questioned due to the imperfect analytical recovery of quantitative microbiological methods and the considerable variation among fully replicated measurements. The random error in analytical recovery estimates and unbiased concentration estimates may be attributable to several sources, and knowing the relative contribution from each source can facilitate strategic design of experiments to yield more precise data or provide an acceptable level of information with fewer data. Herein, variance decomposition using the law of total variance is applied to previously published probabilistic models to explore the relative contributions of various sources of random error and to develop tools to aid experimental design. This work focuses upon enumeration-based methods with imperfect analytical recovery (such as enumeration of Cryptosporidium oocysts), but the results also yield insights about plating methods and microbial methods in general. Using two hypothetical analytical recovery profiles, the variance decomposition method is used to explore 1) the design of an experiment to quantify variation in analytical recovery (including the size and precision of seeding suspensions and the number of samples), and 2) the design of an experiment to estimate a single microorganism concentration (including sample volume, effects of improving analytical recovery, and replication). In one illustrative example, a strategically designed analytical recovery experiment with 6 seeded samples would provide as much information as an alternative experiment with 15 seeded samples. Several examples of diminishing returns are illustrated to show that efforts to reduce error in analytical recovery and concentration estimates can have negligible effect if they are directed at trivial error sources.


Assuntos
Monitoramento Ambiental/métodos , Microbiologia da Água , Cryptosporidium/fisiologia , Modelos Estatísticos
11.
Water Res ; 47(16): 6244-57, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24075721

RESUMO

Over 3500 individual water samples, for 131 sampling times, targeting waterborne pathogens/fecal indicator bacteria were collected during a 7-year period from 4 sites along an intermittent stream running through a small livestock pasture system with and without cattle access-to-stream restriction measures. The study assessed the impact of cattle pasturing/riparian zone protection on: pathogen (bacterial, viral, parasite) occurrence, concentrations of fecal indicators, and quantitative microbial risk assessments (QMRA) of the risk of Cryptosporidium, Giardia and Escherichia coli O157:H7 infection in humans. Methodologies were developed to compute QMRA mean risks on the basis of water samples exhibiting potentially human infectious Cryptosporidium and E. coli based on genotyping Crytosporidium, and E. coli O157:H7 presence/absence information paired with enumerated E. coli. All Giardia spp. were considered infectious. No significant pasturing treatment effects were observed among pathogens, with the exception of Campylobacter spp. and E. coli O157:H7. Campylobacter spp. prevalence significantly decreased downstream through pasture treatments and E. coli O157:H7 was observed in a few instances in the middle of the unrestricted pasture. Densities of total coliform, fecal coliform, and E. coli reduced significantly downstream in the restricted pasture system, but not in the unrestricted system. Seasonal and flow conditions were associated with greater indicator bacteria densities, especially in the summer. Norovirus GII was detected at rates of 7-22% of samples for all monitoring sites, and rotavirus in 0-7% of samples for all monitoring sites; pasture treatment trends were not evident, however. Seasonal and stream flow variables (and their interactions) were relatively more important than pasture treatments for initially stratifying pathogen occurrence and higher fecal indicator bacteria densities. Significant positive associations among fecal indicator bacteria and Campylobacter spp. detection were observed. For QMRA, adjusting for the proportion of Cryptosporidium spp. detected that are infectious for humans reduces downstream risk estimates by roughly one order of magnitude. Using QMRA in this manner provides a more refined estimate of beneficial management practice effects on pathogen exposure risks to humans.


Assuntos
Fenômenos Fisiológicos Bacterianos , Parasitos/fisiologia , Rios , Fenômenos Fisiológicos Virais , Microbiologia da Água , Criação de Animais Domésticos , Animais , Carga Bacteriana , Bovinos , Humanos , Densidade Demográfica , Prevalência , Medição de Risco , Rios/microbiologia , Rios/parasitologia , Rios/virologia , Estações do Ano , Movimentos da Água , Zoonoses/epidemiologia
12.
Water Res ; 47(10): 3255-72, 2013 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-23623467

RESUMO

Human campylobacteriosis is the leading bacterial gastrointestinal illness in Canada; environmental transmission has been implicated in addition to transmission via consumption of contaminated food. Information about Campylobacter spp. occurrence at the watershed scale will enhance our understanding of the associated public health risks and the efficacy of source water protection strategies. The overriding purpose of this study is to provide a quantitative framework to assess and compare the relative public health significance of watershed microbial water quality associated with agricultural BMPs. A microbial monitoring program was expanded from fecal indicator analyses and Campylobacter spp. presence/absence tests to the development of a novel, 11-tube most probable number (MPN) method that targeted Campylobacter jejuni, Campylobacter coli, and Campylobacter lari. These three types of data were used to make inferences about theoretical risks in a watershed in which controlled tile drainage is widely practiced, an adjacent watershed with conventional (uncontrolled) tile drainage, and reference sites elsewhere in the same river basin. E. coli concentrations (MPN and plate count) in the controlled tile drainage watershed were statistically higher (2008-11), relative to the uncontrolled tile drainage watershed, but yearly variation was high as well. Escherichia coli loading for years 2008-11 combined were statistically higher in the controlled watershed, relative to the uncontrolled tile drainage watershed, but Campylobacter spp. loads for 2010-11 were generally higher for the uncontrolled tile drainage watershed (but not statistically significant). Using MPN data and a Bayesian modelling approach, higher mean Campylobacter spp. concentrations were found in the controlled tile drainage watershed relative to the uncontrolled tile drainage watershed (2010, 2011). A second-order quantitative microbial risk assessment (QMRA) was used, in a relative way, to identify differences in mean Campylobacter spp. infection risks among monitoring sites for a hypothetical exposure scenario. Greater relative mean risks were obtained for sites in the controlled tile drainage watershed than in the uncontrolled tile drainage watershed in each year of monitoring with pair-wise posterior probabilities exceeding 0.699, and the lowest relative mean risks were found at a downstream drinking water intake reference site. The second-order modelling approach was used to partition sources of uncertainty, which revealed that an adequate representation of the temporal variation in Campylobacter spp. concentrations for risk assessment was achieved with as few as 10 MPN data per site. This study demonstrates for the first time how QMRA can be implemented to evaluate, in a relative sense, the public health implications of controlled tile drainage on watershed-scale water quality.


Assuntos
Campylobacter , Escherichia coli , Modelos Teóricos , Medição de Risco/métodos , Rios/microbiologia , Microbiologia da Água , Agricultura , Teorema de Bayes , Campylobacter/patogenicidade , Infecções por Campylobacter/epidemiologia , Canadá , Monitoramento Ambiental/métodos , Escherichia coli/patogenicidade , Infecções por Escherichia coli/epidemiologia , Fezes/microbiologia , Humanos , Ontário , Saúde Pública , Qualidade da Água
13.
Water Res ; 47(7): 2399-408, 2013 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-23481286

RESUMO

Quantitative microbial risk assessment (QMRA) is a tool to evaluate the potential implications of pathogens in a water supply or other media and is of increasing interest to regulators. In the case of potentially pathogenic protozoa (e.g. Cryptosporidium oocysts and Giardia cysts), it is well known that the methods used to enumerate (oo)cysts in samples of water and other media can have low and highly variable analytical recovery. In these applications, QMRA has evolved from ignoring analytical recovery to addressing it in point-estimates of risk, and then to addressing variation of analytical recovery in Monte Carlo risk assessments. Often, variation of analytical recovery is addressed in exposure assessment by dividing concentration values that were obtained without consideration of analytical recovery by random beta-distributed recovery values. A simple mathematical proof is provided to demonstrate that this conventional approach to address non-constant analytical recovery in drinking water QMRA will lead to overestimation of mean pathogen concentrations. The bias, which can exceed an order of magnitude, is greatest when low analytical recovery values are common. A simulated dataset is analyzed using a diverse set of approaches to obtain distributions representing temporal variation in the oocyst concentration, and mean annual risk is then computed from each concentration distribution using a simple risk model. This illustrative example demonstrates that the bias associated with mishandling non-constant analytical recovery and non-detect samples can cause drinking water systems to be erroneously classified as surpassing risk thresholds.


Assuntos
Cryptosporidium/isolamento & purificação , Água Potável/parasitologia , Giardia/isolamento & purificação , Modelos Teóricos , Medição de Risco/métodos , Animais , Viés , Simulação por Computador , Oocistos/citologia , Probabilidade , Purificação da Água
14.
Water Res ; 45(2): 427-38, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20851444

RESUMO

Knowledge of the variability in pathogen or indicator concentrations over time at a particular location (e.g. in drinking water sources) is essential in implementation of concentration-based regulations and in quantitative microbial risk assessment. Microbial enumeration methods, however, are known to yield highly variable counts (even among replicates) and some methods are prone to substantial losses (i.e. only a fraction of the target microorganisms in a sample are observed). Consequently, estimated microorganism concentrations may be biased and only a fraction of the variability that is observed in temporally distributed concentration estimates is due to variability in concentration itself. These issues have often been ignored in the past, and approaches to integrate knowledge about the measurement error associated with enumeration methods into decisions have not been standardized. Here, an existing model that describes variability in microorganism counts as a function of sample volume and the analytical recovery of the enumeration method is expanded to include temporal concentration variability and sample-specific recovery information. This model is used to demonstrate that microorganism counts and analytical recovery are not independent (as has often been assumed), even if the correlation is obscured by other sources of variability in the data. It is also used as an experimental design tool to evaluate strategies that may yield more accurate concentration estimates. Finally, the model is implemented in a Bayesian framework (with a Gibbs sampling algorithm) to quantify temporal concentration variability with appropriate consideration of measurement errors in the data and the analytical recovery of the enumeration method. We demonstrate by simulation that this statistical approach facilitates risk analyses that appropriately model variability in microorganism concentrations given the available data and that it enables decisions based on quantitative measures of uncertainty.


Assuntos
Medição de Risco/métodos , Microbiologia da Água , Abastecimento de Água , Teorema de Bayes , Tomada de Decisões , Modelos Estatísticos , Método de Monte Carlo , Incerteza , Microbiologia da Água/normas
17.
Arch Womens Ment Health ; 7(1): 19-26, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-14963729

RESUMO

We compared the number and quality of life events reported by depressed perimenopausal women and a non-depressed comparison group. Additionally, we examined the effects of the presence of hot flushes on life event reports. All women were 44-55 years old, had irregular menses and elevated plasma gonadotropin levels. The Psychiatric Epidemiology Research Interview recorded both the frequency of occurrence and the desirability of life events experienced by the women during the six months prior to the interview. Depressed perimenopausal women (n=50) reported significantly more undesirable events [Student's t-test (unpaired) with Bonferroni correction, t(98)=3.9, p=0.001] but not more exit events (e.g., divorce, last child leaving home or death in family) (t(98)=0.9, p=NS) compared to the non-depressed women (n=50). There were no effects of hot flushes on these diagnostic differences. The "empty nest" syndrome does not appear to be relevant in the development of perimenopausal depression. Nevertheless, independent of the presence of hot flushes, perimenopausal depressed women are more likely to report both negative life events and diminished self esteem.


Assuntos
Climatério/psicologia , Depressão/epidemiologia , Acontecimentos que Mudam a Vida , Estresse Psicológico/epidemiologia , Adulto , Climatério/sangue , Depressão/psicologia , Feminino , Hormônio Foliculoestimulante/sangue , Fogachos/psicologia , Humanos , Entrevista Psicológica , Pessoa de Meia-Idade , Qualidade de Vida , Fatores de Risco , Autoimagem , Estresse Psicológico/psicologia
18.
Gynecol Endocrinol ; 19(6): 335-43, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15724808

RESUMO

Despite consistent evidence that premenstrual dysphoria (PMD) is not characterized by abnormalities in basal ovarian hormone secretion, the possibility remains that PMD is associated with an abnormality in the regulation of the hypothalamic-pituitary-ovarian (HPO) axis. We studied HPO axis regulation in 11 women with prospectively confirmed PMD and 20 asymptomatic controls, during both the follicular and luteal phases of the menstrual cycle. Plasma levels of the gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), were obtained before and after stimulation with gonadotropin-releasing hormone (GnRH) (100 microg intravenously). Potential diagnostic- and menstrual cycle phase-related diferences in basal and plasma hormone levels were analyzed by repeated-measures analysis of variance. No significant differences were observed between women with PMD and controls in either basal or stimulated levels of FSH and LH. Stimulated FSH was significantly increased and stimulated LH was significantly decreased during the follicular compared with the luteal phase in both women with PMD and controls. These data are consistent with prior findings of normal basal reproductive hormone levels in women with PMD. Our data suggest the absence in women with PMD of an abnormality of dynamic ovarian function as measured by GnRH stimulation.


Assuntos
Hormônio Foliculoestimulante/sangue , Hormônio Liberador de Gonadotropina , Hormônio Luteinizante/sangue , Ovário/fisiopatologia , Síndrome Pré-Menstrual/sangue , Adulto , Desidroepiandrosterona/sangue , Estradiol/sangue , Estrona/sangue , Feminino , Humanos , Pessoa de Meia-Idade , Síndrome Pré-Menstrual/fisiopatologia , Progesterona/sangue , Testosterona/sangue
19.
Psychoneuroendocrinology ; 28(3): 317-31, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12573299

RESUMO

OBJECTIVE: Despite widespread abuse of anabolic-androgenic steroids (AAS), the endocrine effects of supraphysiologic doses of these compounds remain unclear. We administered the AAS methyltestosterone (MT) to 20 normal volunteers in an in-patient setting, examined its effects on levels of pituitary-gonadal, -thyroid, and -adrenal hormones, and examined potential relationships between endocrine changes and MT-induced psychological symptoms. METHOD: Subjects received MT (three days of 40 mg/day, then three days of 240 mg/day) or placebo in a fixed sequence with neither subjects nor raters aware of order. Samples were obtained at the ends of the baseline, high-dose MT and withdrawal phases. Potential relationships between hormonal changes and visual analog scale measured mood changes were examined. RESULTS: Significant decreases in plasma levels of gonadotropins, gonadal steroids, sex hormone binding globulin, free T3 and T4, and thyroid binding globulin (Bonferroni t, p<0.01 for each) were seen during high-dose MT; free thyroxine and TSH increased during high-dose MT, with TSH increases reaching significance during withdrawal. No significant changes in pituitary-adrenal hormones were observed. Changes in free thyroxine significantly correlated with changes in aggressiveness (anger, violent feelings, irritability) (r=0.5,p=0.02) and changes in total testosterone correlated significantly with changes in cognitive cluster symptoms (forgetfulness, distractibility) (r=0.52,p=0.02). Hormonal changes did not correlate with plasma MT levels. CONCLUSIONS: Acute high-dose MT administration acutely suppresses the reproductive axis and significantly impacts thyroid axis balance without a consistent effect on pituitary-adrenal hormones. Mood and behavioral effects observed during AAS use may in part reflect secondary hormonal changes.


Assuntos
Afeto/efeitos dos fármacos , Anabolizantes/farmacologia , Metiltestosterona/farmacologia , Sistemas Neurossecretores/efeitos dos fármacos , Adolescente , Adulto , Agressão/efeitos dos fármacos , Análise de Variância , Androgênios/metabolismo , Relação Dose-Resposta a Droga , Estrogênios/metabolismo , Humanos , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Masculino , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Valores de Referência , Globulina de Ligação a Hormônio Sexual/efeitos dos fármacos , Testes de Função Tireóidea , Hormônios Tireóideos/metabolismo
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