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1.
Plant Sci ; 295: 110212, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32534607

RESUMO

Emmer wheat (Triticum dicoccon Schrank) is a potential source of new genetic diversity for the improvement of hexaploid bread wheat. Emmer wheat was crossed and backcrossed to bread wheat and 480 doubled haploids (DHs) were produced from BC1F1 plants with hexaploid appearance derived from 19 crossses. These DHs were screened under well-watered conditions (E1) in 2013 to identify high-yielding materials with similar phenology. One-hundred and eighty seven DH lines selected on this basis, 4 commercial bread wheat cultivars and 9 bread wheat parents were then evaluated in extensive field experiments under two contrasting moisture regimes in north-western NSW in 2014 and 2015. A significant range in the water-use-efficiency of grain production (WUEGrain) was observed among the emmer derivatives. Of these, 8 hexaploid lines developed from 8 different emmer wheat parents had significantly improved intrinsic water-use-efficiency (WUEintr) and instantaneous water-use-efficiency (WUEi) compared to their bread wheat recurrent parents. Accurate and large scale field-based phenotyping was effective in identifying emmer wheat derived lines with superior performance to their hexaploid bread wheat recurrent parents under moisture stress.


Assuntos
Melhoramento Vegetal , Triticum/fisiologia , Água/metabolismo , Secas , New South Wales , Poliploidia , Triticum/genética , Triticum/crescimento & desenvolvimento
2.
Front Plant Sci ; 10: 1444, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31781148

RESUMO

Triacylglycerol is a major component of vegetable oil in seeds and fruits of many plants, but its production in vegetative tissues is rather limited. It would be intriguing and important to explore any possibility to expand current oil production platforms, for example from the plant vegetative tissues. By expressing a suite of transgenes involved in the triacylglycerol biosynthesis, we have previously observed substantial accumulation of triacylglycerol in tobacco (Nicotiana tabacum) leaf and potato (Solanum tuberosum) tuber. In this study, simultaneous RNA interference (RNAi) downregulation of ADP-glucose pyrophosphorylase (AGPase) and Sugar-dependent1 (SDP1), was able to increase the accumulation of triacylglycerol and other lipids in both wild type potato and the previously generated high oil potato line 69. Particularly, a 16-fold enhancement of triacylglycerol production was observed in the mature transgenic tubers derived from the wild type potato, and a two-fold increase in triacylglycerol was observed in the high oil potato line 69, accounting for about 7% of tuber dry weight, which is the highest triacylglycerol accumulation ever reported in potato. In addition to the alterations of lipid content and fatty acid composition, sugar accumulation, starch content of the RNAi potato lines in both tuber and leaf tissues were also substantially changed, as well as the tuber starch properties. Microscopic analysis further revealed variation of lipid droplet distribution and starch granule morphology in the mature transgenic tubers compared to their parent lines. This study reflects that the carbon partitioning between lipid and starch in both leaves and non-photosynthetic tuber tissues, respectively, are highly orchestrated in potato, and it is promising to convert low-energy starch to storage lipids via genetic manipulation of the carbon metabolism pathways.

3.
Phys Med ; 48: 55-64, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29728229

RESUMO

This article aims to present the protocol on Quality Controls in Digital Mammography published online in 2015 by the European Federation of Organisations for Medical Physics (EFOMP) which was developed by a Task Force under the Mammo Working Group. The main objective of this protocol was to define a minimum set of easily implemented quality control tests on digital mammography systems that can be used to assure the performance of a system within a set and acceptable range. Detailed step-by-step instructions have been provided, limiting as much as possible any misinterpretations or variations by the person performing. It is intended that these tests be implemented as part of the daily routine of medical physicists and system users throughout Europe in a harmonised way so allowing results to be compared. In this paper the main characteristics of the protocol are illustrated, including examples, together with a brief summary of the contents of each chapter. Finally, instructions for the download of the full protocol and of the related software tools are provided.


Assuntos
Mamografia/normas , Garantia da Qualidade dos Cuidados de Saúde/métodos , Sociedades Científicas , Humanos , Mamografia/efeitos adversos , Mamografia/instrumentação , Doses de Radiação , Exposição à Radiação
4.
Br J Ophthalmol ; 98(8): 1042-9, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24682180

RESUMO

BACKGROUND/AIMS: Retinal screening programmes in England and Scotland have similar photographic grading schemes for background (non-proliferative) and proliferative diabetic retinopathy, but diverge over maculopathy. We looked for the most cost-effective method of identifying diabetic macular oedema from retinal photographs including the role of automated grading and optical coherence tomography, a technology that directly visualises oedema. METHODS: Patients from seven UK centres were recruited. The following features in at least one eye were required for enrolment: microaneurysms/dot haemorrhages or blot haemorrhages within one disc diameter, or exudates within one or two disc diameters of the centre of the macula. Subjects had optical coherence tomography and digital photography. Manual and automated grading schemes were evaluated. Costs and QALYs were modelled using microsimulation techniques. RESULTS: 3540 patients were recruited, 3170 were analysed. For diabetic macular oedema, England's scheme had a sensitivity of 72.6% and specificity of 66.8%; Scotland's had a sensitivity of 59.5% and specificity of 79.0%. When applying a ceiling ratio of £30,000 per quality adjusted life years (QALY) gained, Scotland's scheme was preferred. Assuming automated grading could be implemented without increasing grading costs, automation produced a greater number of QALYS for a lower cost than England's scheme, but was not cost effective, at the study's operating point, compared with Scotland's. The addition of optical coherence tomography, to each scheme, resulted in cost savings without reducing health benefits. CONCLUSIONS: Retinal screening programmes in the UK should reconsider the screening pathway to make best use of existing and new technologies.


Assuntos
Retinopatia Diabética/diagnóstico , Edema Macular/diagnóstico , Programas de Rastreamento/economia , Fotografação/economia , Adulto , Idoso , Automação , Análise Custo-Benefício , Retinopatia Diabética/economia , Feminino , Humanos , Edema Macular/economia , Masculino , Programas de Rastreamento/métodos , Pessoa de Meia-Idade , Fotografação/métodos , Estudos Prospectivos , Melhoria de Qualidade/economia , Anos de Vida Ajustados por Qualidade de Vida , Sensibilidade e Especificidade , Tomografia de Coerência Óptica/economia , Tomografia de Coerência Óptica/métodos , Reino Unido
5.
J Biol Rhythms ; 28(1): 38-50, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23382590

RESUMO

In vertebrates, reproductive output often increases with age. Unlike older birds, first-year photoperiodic birds lack experience with the reproductively stimulatory effects of long day lengths (photostimulation). We examined whether age-related differences in annual reproductive development could be partially attributed to previous experience with photostimulation in the photoperiodic house finch (Carpodacus mexicanus). By manipulating photoperiod, we generated 2 groups of first-year females: a photo-experienced group that underwent 1 photoperiodically induced cycle of gonadal development and regression and a photo-naïve group exposed to long days since hatch. We transferred both groups from long to short days and then photostimulated and exposed them to male birdsong prior to sacrifice. Following concurrent photostimulation, both groups exhibited similar plasma luteinizing hormone surges and hypothalamic vasoactive intestinal polypeptide immunoreactivity. In contrast, hypothalamic gonadotropin-releasing hormone immunoreactivity and circulating vitellogenin levels were higher in photo-experienced birds, and yolk deposition occurred in only 2 females, both of which were photo-experienced. Our results demonstrate that photo-experience enhances some aspects of early photo-induced reproductive development and raise the hypothesis that photo-experience may account for at least some age-related variation in reproductive output.


Assuntos
Tentilhões/fisiologia , Fotoperíodo , Reprodução/fisiologia , Animais , Índice de Massa Corporal , Feminino , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/fisiologia , Luz , Hormônio Luteinizante/metabolismo , Masculino , Canto , Vitelogeninas/metabolismo
6.
Horm Behav ; 61(5): 741-9, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22504307

RESUMO

The Challenge Hypothesis postulates that male vertebrates can respond to social challenges, such as simulated territorial intrusions, by rapidly increasing their concentrations of plasma androgens, such as testosterone (T). This increase may facilitate the expression of aggressive behavior and lead to persistence of this behavior even after withdrawal of the challenge, thus potentially promoting territoriality and the probability of winning future challenges. The scope of the Challenge Hypothesis was tested by exposing free-ranging male Cassin's Sparrows, Peucaea cassinii, to conspecific song playback (SPB) at the beginning of the vernal nesting season. Exposure to SPB stimulated aggressive behavior but did not influence plasma T. Furthermore, plasma T did not correlate with the duration of exposure to SPB, and the behavioral response to SPB did not differ in males that were challenged a second time shortly after the first challenge. As birds were investigated at a stage of their reproductive cycle when plasma T is presumably seasonally high due to photostimulation, the lack of hormonal response to SPB may have been due to the hypothalamus-pituitary-gonadal axis secreting hormones at maximum rates. This was not the case, however, because administration of gonadotropin-releasing hormone I rapidly stimulated the secretion of luteinizing hormone (LH) and T, and treatment with ovine LH rapidly stimulated T secretion.


Assuntos
Comportamento Animal/fisiologia , Comportamento de Retorno ao Território Vital , Hormônios/metabolismo , Pardais/fisiologia , Vocalização Animal/fisiologia , Algoritmos , Animais , Animais Selvagens/sangue , Animais Selvagens/metabolismo , Animais Selvagens/fisiologia , Voo Animal/fisiologia , Hormônio Liberador de Gonadotropina/sangue , Hormônio Liberador de Gonadotropina/metabolismo , Comportamento de Retorno ao Território Vital/fisiologia , Hormônios/sangue , Hormônio Luteinizante/sangue , Hormônio Luteinizante/metabolismo , Masculino , Comportamento Sexual Animal/fisiologia , Pardais/sangue , Pardais/metabolismo , Territorialidade , Testosterona/sangue , Testosterona/metabolismo
7.
Gen Comp Endocrinol ; 176(2): 167-72, 2012 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-22326349

RESUMO

Gonadotropin-releasing hormone (GnRH) is central to the control of vertebrate reproductive cycles and since GnRH orthologs are also present in invertebrates, it is likely that the common ancestor of bilateral animals possessed a GnRH-like peptide. In order to understand the evolutionary and comparative biology of GnRH peptides we cloned the cDNA transcripts of prepro GnRH-like peptides from two species of bivalve molluscs, the Yesso scallop Patinopecten yessoensis and the Pacific oyster Crassostrea gigas. We compared their deduced uncleaved and mature amino acid sequences with those from other invertebrates and vertebrates, and determined their sites of expression and biological activity. The two molluscan GnRH sequences increased the number of known protostome GnRHs to six different forms, indicating the current classification of protostome GnRHs requires further revision. In both molluscs, RT-PCR analysis showed that the genes were highly expressed in nervous tissue with lower levels present in peripheral tissues including the gonads, while immunocytochemistry, using anti-octopus GnRH-like peptide, demonstrated the presence of GnRH-like peptide in neural tissue. Putative scallop GnRH-like peptide stimulated spermatogonial cell division in cultured scallop testis, but the scallop GnRH-like peptide did not stimulate LH release from cultured quail pituitary cells. This is the first report of the cloning of bivalve GnRH-like peptide genes and of molluscan GnRH-like peptides that are biologically active in molluscs, but not in a vertebrate.


Assuntos
Hormônio Liberador de Gonadotropina/farmacologia , Gônadas/efeitos dos fármacos , Gônadas/metabolismo , Reprodução/efeitos dos fármacos , Animais , Imuno-Histoquímica , Masculino , Moluscos , Técnicas de Amplificação de Ácido Nucleico , Filogenia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Técnicas de Cultura de Tecidos
8.
Aust N Z J Obstet Gynaecol ; 51(6): 518-22, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21806587

RESUMO

BACKGROUND: The Winnunga Nimmityjah Aboriginal Health Service Aboriginal Midwifery Access Program (AMAP) was established in 2001 to provide antenatal care, birth support and postnatal care to clients in the Australian Capital Territory (ACT). AIM: To describe the uptake and impact of AMAP services on access to antenatal care, behavioural risk factors and pregnancy outcomes and to compare the characteristics of AMAP clients with other women giving birth in the ACT. METHODS: A descriptive study of medical records for AMAP clients who gave birth in 2004-2008. OUTCOME MEASURES: maternal and baby characteristics, antenatal visits, behavioural risk factors and complications. Characteristics of AMAP clients were compared with the ACT Maternal and Perinatal Collection. RESULTS: Of 187 women, 11.2% were aged <20 years, 50.3% presented in the first trimester and 94.7% attended five or more antenatal visits. Of 193 babies, 17.1% were born preterm and 18.1% had low birthweight. Compared with the ACT Maternal and Perinatal Collection, Aboriginal and Torres Strait Islander AMAP clients had a higher smoking rate (63.8 vs 49.0%), a lower caesarean delivery rate (20.0 vs 27.6%), a slightly lower proportion of preterm babies (18.8 vs 21.6%) and a slightly lower proportion of low-birthweight babies (18.8 vs 21.0%). CONCLUSIONS: Aboriginal Midwifery Access Program provides high-quality antenatal care in a trusted environment. The high rate of smoking in pregnancy needs to be addressed.


Assuntos
Peso ao Nascer , Serviços de Saúde Materna/estatística & dados numéricos , Tocologia , Havaiano Nativo ou Outro Ilhéu do Pacífico , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Adulto , Território da Capital Australiana/epidemiologia , Cesárea/estatística & dados numéricos , Feminino , Comportamentos Relacionados com a Saúde/etnologia , Acessibilidade aos Serviços de Saúde , Humanos , Recém-Nascido de Baixo Peso , Recém-Nascido , Visita a Consultório Médico/estatística & dados numéricos , Gravidez , Primeiro Trimestre da Gravidez , Segundo Trimestre da Gravidez , Nascimento Prematuro/etnologia , Cuidado Pré-Natal/estatística & dados numéricos , Estudos Retrospectivos , Fumar , Adulto Jovem
9.
Curr Diabetes Rev ; 7(4): 246-52, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21644913

RESUMO

Systematic screening for diabetic retinopathy using retinal photography has been shown to reduce the incidence of blindness among people with diabetes. The implementation of diabetic retinopathy screening programmes faces several challenges. Consequently, methods for improving the efficiency of screening are being sought, one of which is the automation of image grading involving detection of images with either disease or of inadequate quality using computer software. This review aims to bring together the available evidence that is suitable for making a judgement about whether automated grading systems could be used effectively in diabetic retinopathy screening. To do this, it focuses on studies made by the few centres who have presented results tests of automated grading software on large sets of patients or screening episodes. It also considers economic model analyses and papers describing the effectiveness of manual grading in order that the effect of replacing stages of manual grading by automated grading can be judged. In conclusion, the review shows that there is sufficient evidence to suggest that automated grading, operating as a disease / no disease grader, is safe and could reduce the workload of manual grading in diabetic retinopathy screening.


Assuntos
Retinopatia Diabética/diagnóstico , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Reconhecimento Automatizado de Padrão/estatística & dados numéricos , Testes de Campo Visual/métodos , Humanos , Programas de Rastreamento/métodos , Reconhecimento Automatizado de Padrão/métodos
10.
Br J Ophthalmol ; 94(12): 1606-10, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20858722

RESUMO

BACKGROUND/AIMS: Automated grading software has the potential to reduce the manual grading workload within diabetic retinopathy screening programmes. This audit was undertaken at the request of Scotland's National Diabetic Retinopathy Screening Collaborative to assess whether the introduction of automated grading software into the national screening programme would be safe, robust and effective. METHODS: Automated grading, performed by software for image quality assessment and for microaneurysm/dot haemorrhage detection, was carried out on 78,601 images, obtained from 33,535 consecutive patients, which had been manually graded at one of two regional diabetic retinopathy screening programmes. Cases where the automated grading software assessment indicated gradable images with no disease but the screening programme indicated ungradable images or disease more severe than mild retinopathy were arbitrated by seven senior ophthalmologists. RESULTS: 100% (180/180) of patients with proliferative retinopathy, 100% (324/324) with referable background retinopathy, 100% (193/193) with observable background retinopathy, 97.3% (1099/1130) with referable maculopathy, 99.2% (384/387) with observable maculopathy and 99.8% (1824/1827) with ungradable images were detected by the software. CONCLUSION: The automated grading software operated to previously published results when applied to a large, unselected population attending two regional screening programmes. Manual grading workload reduction would be 36.3%.


Assuntos
Retinopatia Diabética/diagnóstico , Diagnóstico por Computador/métodos , Hemorragia Retiniana/diagnóstico , Auditoria Clínica , Retinopatia Diabética/epidemiologia , Feminino , Humanos , Masculino , Programas de Rastreamento , Negociação , Avaliação de Programas e Projetos de Saúde , Hemorragia Retiniana/epidemiologia , Escócia/epidemiologia , Sensibilidade e Especificidade , Índice de Gravidade de Doença , Software
11.
Gen Comp Endocrinol ; 169(1): 82-90, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20691650

RESUMO

We used a free-ranging, seasonally breeding adult male songbird, the rufous-winged sparrow, Aimophila carpalis, to investigate the effects of acute stress-induced by capture followed by restraint, on the hypothalamo-pituitary-testicular axis. Intra- and interindividual comparisons revealed that males decreased their plasma testosterone (T) by 37-52% in response to acute stress. The decrease occurred within 15 min of capture and persisted for at least another 15 min. Within 15 min, the decrease in plasma T was not associated with a reduction in plasma luteinizing hormone (LH). Thirty minutes after capture and restraint, the decrease in plasma T either was likewise not associated with decreased plasma LH (intraindividual comparison) or concurred with a reduction in plasma LH (interindividual comparison). These observations indicate that effects of stress may have been mediated at the pituitary gland and also directly at the testicular levels. To address this question, we measured the hormonal response to an injection of the glutamate receptor agonist N-methyl-d,l-aspartate (NMA) to stimulate to stimulate the release of gonadotropin-releasing hormone (GnRH) or of GnRH to stimulate the release of LH. Treatment with NMA did not change plasma LH, presumably because the birds were in breeding condition and already secreting GnRH at a maximum rate. Administration of GnRH increased plasma LH equally in birds that were or were not stressed before the treatment. An injection of purified ovine LH (oLH) increased plasma T equally in birds that were or were not acutely stressed before the hormone injection. Thus, the observed acute stress-induced decrease in plasma T was apparently not mediated by decreased responsiveness of the pituitary gland to GnRH or of the testes to LH. Decreased plasma T following stress may involve a direct impairment of the testicular endocrine function.


Assuntos
Estresse Fisiológico/fisiologia , Testosterona/sangue , Animais , Hormônio Liberador de Gonadotropina/sangue , Hormônio Liberador de Gonadotropina/farmacologia , Hormônio Luteinizante/sangue , Masculino , N-Metilaspartato/farmacologia , Hipófise/efeitos dos fármacos , Hipófise/metabolismo , Aves Canoras , Testículo/efeitos dos fármacos , Testículo/metabolismo
12.
Br J Ophthalmol ; 94(6): 706-11, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19661069

RESUMO

BACKGROUND/AIMS: Automated grading has the potential to improve the efficiency of diabetic retinopathy screening services. While disease/no disease grading can be performed using only microaneurysm detection and image-quality assessment, automated recognition of other types of lesions may be advantageous. This study investigated whether inclusion of automated recognition of exudates and haemorrhages improves the detection of observable/referable diabetic retinopathy. METHODS: Images from 1253 patients with observable/referable retinopathy and 6333 patients with non-referable retinopathy were obtained from three grading centres. All images were reference-graded, and automated disease/no disease assessments were made based on microaneurysm detection and combined microaneurysm, exudate and haemorrhage detection. RESULTS: Introduction of algorithms for exudates and haemorrhages resulted in a statistically significant increase in the sensitivity for detection of observable/referable retinopathy from 94.9% (95% CI 93.5 to 96.0) to 96.6% (95.4 to 97.4) without affecting manual grading workload. CONCLUSION: Automated detection of exudates and haemorrhages improved the detection of observable/referable retinopathy.


Assuntos
Retinopatia Diabética/complicações , Retinopatia Diabética/diagnóstico , Diagnóstico por Computador/métodos , Exsudatos e Transudatos/metabolismo , Hemorragia Retiniana/etiologia , Índice de Gravidade de Doença , Algoritmos , Técnicas de Diagnóstico Oftalmológico , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Programas de Rastreamento/métodos , Padrões de Referência
13.
BMC Plant Biol ; 9: 143, 2009 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-19958559

RESUMO

BACKGROUND: TILLING (Targeting Induced Local Lesions IN Genomes) is a powerful tool for reverse genetics, combining traditional chemical mutagenesis with high-throughput PCR-based mutation detection to discover induced mutations that alter protein function. The most popular mutation detection method for TILLING is a mismatch cleavage assay using the endonuclease CelI. For this method, locus-specific PCR is essential. Most wheat genes are present as three similar sequences with high homology in exons and low homology in introns. Locus-specific primers can usually be designed in introns. However, it is sometimes difficult to design locus-specific PCR primers in a conserved region with high homology among the three homoeologous genes, or in a gene lacking introns, or if information on introns is not available. Here we describe a mutation detection method which combines High Resolution Melting (HRM) analysis of mixed PCR amplicons containing three homoeologous gene fragments and sequence analysis using Mutation Surveyor software, aimed at simultaneous detection of mutations in three homoeologous genes. RESULTS: We demonstrate that High Resolution Melting (HRM) analysis can be used in mutation scans in mixed PCR amplicons containing three homoeologous gene fragments. Combining HRM scanning with sequence analysis using Mutation Surveyor is sensitive enough to detect a single nucleotide mutation in the heterozygous state in a mixed PCR amplicon containing three homoeoloci. The method was tested and validated in an EMS (ethylmethane sulfonate)-treated wheat TILLING population, screening mutations in the carboxyl terminal domain of the Starch Synthase II (SSII) gene. Selected identified mutations of interest can be further analysed by cloning to confirm the mutation and determine the genomic origin of the mutation. CONCLUSION: Polyploidy is common in plants. Conserved regions of a gene often represent functional domains and have high sequence similarity between homoeologous loci. The method described here is a useful alternative to locus-specific based methods for screening mutations in conserved functional domains of homoeologous genes. This method can also be used for SNP (single nucleotide polymorphism) marker development and eco-TILLING in polyploid species.


Assuntos
Análise Mutacional de DNA/métodos , Mutação , Triticum/genética , Alelos , Sequência de Bases , DNA de Plantas/genética , Genes de Plantas , Loci Gênicos , Dados de Sequência Molecular , Proteínas de Plantas/genética , Reação em Cadeia da Polimerase/métodos , Polimorfismo de Nucleotídeo Único , Sensibilidade e Especificidade , Alinhamento de Sequência , Sintase do Amido/genética
14.
Brain Res Bull ; 79(3-4): 201-7, 2009 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-19429192

RESUMO

In order to further advance the understanding of genes involved in avian photoperiodic signaling, a chicken hypothalamic cDNA microarray was made to identify changes in gene expression in the whole hypothalamus of juvenile male domestic chickens after 4 days' photostimulation. The most robust change was a depression in heat shock protein 90B1 (HSP90B1) expression. This observation was confirmed using quantitative PCR, and it was subsequently demonstrated that the depression in HSP90B1 expression first occurs in the anterior hypothalamus after 1 day's photostimulation, and was also depressed in the anterior and basal hypothalamus after 4 days' photostimulation. Four days after an intravenous injection of thyroxine (T4), an avian photomimetic, in short day birds, HSP90B1 expression was depressed in the anterior, but not in the basal hypothalamus. Depressed HSP901 expression after photostimulation or T4 treatment was associated with increased GnRH-I mRNA and plasma LH. HSP90B1 is abundant throughout the brain where it occurs in glial cells, and is involved in regulating white matter plasticity. It is suggested that photoperiodically depressed hypothalamic HSP90B1 may affect glial function in photoperiodic signaling pathways in the neuroendocrine system. This is the first report of a thyroid hormone-responsive gene involved in photoperiodic signaling.


Assuntos
Relógios Biológicos/fisiologia , Ritmo Circadiano/fisiologia , Proteínas de Choque Térmico HSP90 , Fotoperíodo , Transdução de Sinais/fisiologia , Hormônios Tireóideos/metabolismo , Animais , Relógios Biológicos/efeitos dos fármacos , Galinhas , Expressão Gênica , Hormônio Liberador de Gonadotropina/genética , Hormônio Liberador de Gonadotropina/metabolismo , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Hipotálamo/anatomia & histologia , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Hormônio Luteinizante/sangue , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Estimulação Luminosa , Transdução de Sinais/efeitos dos fármacos , Hormônios Tireóideos/farmacologia
15.
Horm Behav ; 54(5): 669-75, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18706906

RESUMO

Many birds and mammals show changes in the hypothalamo-pituitary-gonadal (HPG) axis in response to social or sexual interactions between breeding partners. While alterations in GnRH neuronal activity play an important role in stimulating these changes, it remains unclear if acute behaviorally-induced alterations in GnRH release are accompanied by parallel changes in GnRH synthesis. To investigate this relationship, we examined changes in the activity of GnRH neurons in the brains of male ring doves following brief periods of courtship interactions with females. Such interactions have been previously shown to increase plasma LH in courting male doves at 24 h, but not at 1 h, after pairing with females. In the first study, males allowed to court females for 2 h had 60% more cells that showed immunocytochemical labeling for GnRH-I in the preoptic area (POA) of the hypothalamus than did control males that remained isolated from females. To determine whether an increase in GnRH gene expression preceded this increase in GnRH immunoreactivity in the POA, changes in the number of cells with detectable GnRH-I mRNA in the POA were measured by in situ hybridization following a 1 h period of courtship interactions with females. In this second study, courting males exhibited 40% more cells with GnRH-I in this region than did isolated control males. GnRH-immunoreactive neurons in two other diencephalic regions failed to show these courtship-induced changes. Plasma LH was not elevated after 1 or 2 h of courtship. These results demonstrate that the release of GnRH-I in the POA that is presumably responsible for courtship-induced pituitary and gonadal activation is accompanied by a rapid increase in GnRH synthesis that occurs before plasma LH levels increase. We suggest that this increase in GnRH synthesis is necessary to support the extended period of HPG axis activation that is seen in this species during the 5-10 day period of courtship and nest building activity.


Assuntos
Columbidae/fisiologia , Corte , Hormônio Liberador de Gonadotropina/biossíntese , Animais , Columbidae/sangue , Columbidae/genética , Columbidae/metabolismo , Hormônio Liberador de Gonadotropina/genética , Hormônio Liberador de Gonadotropina/metabolismo , Relações Interpessoais , Hormônio Luteinizante/sangue , Masculino , Modelos Biológicos , Prosencéfalo/metabolismo , RNA Mensageiro/metabolismo , Comportamento Sexual Animal/fisiologia
16.
Nature ; 452(7185): 317-22, 2008 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-18354476

RESUMO

Molecular mechanisms regulating animal seasonal breeding in response to changing photoperiod are not well understood. Rapid induction of gene expression of thyroid-hormone-activating enzyme (type 2 deiodinase, DIO2) in the mediobasal hypothalamus (MBH) of the Japanese quail (Coturnix japonica) is the earliest event yet recorded in the photoperiodic signal transduction pathway. Here we show cascades of gene expression in the quail MBH associated with the initiation of photoinduced secretion of luteinizing hormone. We identified two waves of gene expression. The first was initiated about 14 h after dawn of the first long day and included increased thyrotrophin (TSH) beta-subunit expression in the pars tuberalis; the second occurred approximately 4 h later and included increased expression of DIO2. Intracerebroventricular (ICV) administration of TSH to short-day quail stimulated gonadal growth and expression of DIO2 which was shown to be mediated through a TSH receptor-cyclic AMP (cAMP) signalling pathway. Increased TSH in the pars tuberalis therefore seems to trigger long-day photoinduced seasonal breeding.


Assuntos
Coturnix/fisiologia , Fotoperíodo , Hipófise/metabolismo , Hipófise/efeitos da radiação , Reprodução/fisiologia , Reprodução/efeitos da radiação , Tireotropina/metabolismo , Animais , Galinhas , Coturnix/anatomia & histologia , Coturnix/genética , AMP Cíclico/metabolismo , Escuridão , Indução Enzimática , Feminino , Regulação da Expressão Gênica/efeitos da radiação , Genoma , Genômica , Hipotálamo/metabolismo , Hipotálamo/efeitos da radiação , Iodeto Peroxidase/biossíntese , Iodeto Peroxidase/genética , Iodeto Peroxidase/metabolismo , Luz , Hormônio Luteinizante/metabolismo , Masculino , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Hipófise/anatomia & histologia , Receptores da Tireotropina/metabolismo , Estações do Ano , Transdução de Sinais/efeitos da radiação , Testículo/crescimento & desenvolvimento , Tireotropina/administração & dosagem , Tireotropina/antagonistas & inibidores , Tireotropina/imunologia
17.
Horm Behav ; 53(1): 28-39, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17920598

RESUMO

Prolonged exposure to conspecific song stimulates gonadal function and reproductive hormone secretion in female birds but few studies have investigated the physiological effects of conspecific song exposure on males outside of short-term, aggressive interactions. We exposed male Rufous-winged Sparrows, Aimophila carpalis, either to conspecific song (CS Song), to heterospecific song (Black-throated Sparrow, Amphispiza bilineata; HS Song), or to no recorded song (No Song) for 59 consecutive days (two h per day). Birds were exposed to short days (8L:16D) for the first 21 days of treatment and were then transferred to long days (13L:11D) for the remaining 38 days. During long day exposure, CS Song birds experienced faster growth of testes than HS Song and No Song birds. HS Song birds also grew their testes faster than No Song birds. Plasma luteinizing hormone (LH) and testosterone did not differ between CS Song and No Song birds. However, plasma LH was higher in HS Song birds compared to other groups. There were no differences in hypothalamic immunocytochemical labeling for gonadotropin-releasing hormone, its precursor proGnRH, or gonadotropin-inhibitory hormone, nor were there differences in two song control nuclei volumes (HVC and RA) between CS Song and No Song treatment groups. Furthermore, we found no effect of heterospecific song on free-living Rufous-winged Sparrow aggressive behaviors. These data indicate that long-term exposure to auditory stimuli, such as song, can influence the reproductive system of male songbirds and different types of auditory stimuli can have differential effects on reproductive function.


Assuntos
Percepção Auditiva/fisiologia , Hormônio Liberador de Gonadotropina/metabolismo , Pardais/fisiologia , Testículo/crescimento & desenvolvimento , Vocalização Animal/fisiologia , Estimulação Acústica , Análise de Variância , Animais , Centro Vocal Superior/fisiologia , Hipotálamo/metabolismo , Hormônio Luteinizante/sangue , Masculino , Tamanho do Órgão , Fotoperíodo , Reprodução/fisiologia , Estatísticas não Paramétricas , Testosterona/sangue
18.
Brain Behav Evol ; 71(2): 127-42, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18032888

RESUMO

We investigated the regulation of luteinizing hormone (LH) in the male Rufous-winged Sparrow,Aimophila carpalis, a resident of the Sonoran desert that breeds after irregular summer rains. Although the testes develop in March due to increasing photoperiod and regress in September due to decreasing photoperiod, LH does not consistently increase in the spring as in other photoperiodic birds. However, throughout the year increased plasma LH is correlated with rainfall. To investigate this rainfall-associated regulation of LH secretion, we quantified immunocytochemical labeling for gonadotropin-releasing hormone I (GnRH-I), proGnRH (the GnRH precursor), and gonadotropin-inhibitory hormone (GnIH) in the hypothalamus of free-living adult males caught before (low LH), and during (high LH) the monsoon rainy season. Compared to pre-monsoon birds, birds caught during the monsoon season had larger immunoreactive GnRH-I (GnRH-I-ir) and proGnRH-ir cell bodies, as well as fewer, less densely labeled proGnRH-ir cell bodies. Birds caught during the monsoon had fewer, less densely labeled GnIH-ir cell bodies than birds caught before the monsoon. Further, there was no GnIH-ir labeling in the median eminence on either capture dates, suggesting that GnIH is not released to the pituitary gland via the portal vein at this time of year, but there were fewer GnIH-ir fibers in the preoptic area of birds caught during the monsoon season. Our data support the hypothesis that environmental factors associated with increased rainfall during the monsoon season stimulate GnRH synthesis and release to increase LH secretion. These data also suggest that GnIH could inhibit GnRH neuronal activity prior to the monsoon season.


Assuntos
Animais Selvagens/fisiologia , Hipotálamo/fisiologia , Hormônio Luteinizante/metabolismo , Fotoperíodo , Chuva , Pardais/fisiologia , Animais , Animais Selvagens/metabolismo , Tamanho Celular , Hormônio Liberador de Gonadotropina/metabolismo , Hormônios Hipotalâmicos/metabolismo , Hipotálamo/citologia , Hipotálamo/metabolismo , Imuno-Histoquímica , Hormônio Luteinizante/sangue , Masculino , Eminência Mediana/metabolismo , Precursores de Proteínas/metabolismo , Estações do Ano , Pardais/metabolismo
19.
Phys Med Biol ; 52(24): 7385-96, 2007 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-18065845

RESUMO

Automated image analysis is being widely sought to reduce the workload required for grading images resulting from diabetic retinopathy screening programmes. The recognition of exudates in retinal images is an important goal for automated analysis since these are one of the indicators that the disease has progressed to a stage requiring referral to an ophthalmologist. Candidate exudates were detected using a multi-scale morphological process. Based on local properties, the likelihoods of a candidate being a member of classes exudate, drusen or background were determined. This leads to a likelihood of the image containing exudates which can be thresholded to create a binary decision. Compared to a clinical reference standard, images containing exudates were detected with sensitivity 95.0% and specificity 84.6% in a test set of 13,219 images of which 300 contained exudates. Depending on requirements, this method could form part of an automated system to detect images showing either any diabetic retinopathy or referable diabetic retinopathy.


Assuntos
Retinopatia Diabética/diagnóstico , Exsudatos e Transudatos , Reconhecimento Automatizado de Padrão/métodos , Inteligência Artificial , Técnicas de Diagnóstico Oftalmológico , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Programas de Rastreamento/métodos , Retina/patologia , Drusas Retinianas , Escócia , Sensibilidade e Especificidade
20.
Aust N Z J Public Health ; 31(5): 428-32, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17931289

RESUMO

OBJECTIVE: This study aimed to evaluate the opioid replacement pharmacotherapy at Winnunga Nimmityjah Aboriginal Health Service (Winnunga) in the Australian Capital Territory. METHODS: Existing and new adult patients at Winnunga who were receiving opioid replacement pharmacotherapy were recruited. Twenty-one of 30 eligible patients participated in this cohort study. The Brief Treatment Outcome Measure was administered to patients twice with an interval of at least three months. Primary outcome measures were retention rate in the program and self-reported heroin use. RESULTS: Eighty-one per cent (17/21) of patients remained in treatment at three months. Median self-reported heroin use for existing patients was 0 days/month at initial interview and follow-up (95% CI 0-1). There was no significant difference between self-reported heroin use at initial and follow-up interview (paired Wilcoxon test, R=10, alpha=0.05). Mean self-reported heroin use was 1.5 days/month at initial interview and 2.4 days/month at follow-up. CONCLUSION: The retention rate of 81% and low levels of heroin use suggest that opioid replacement pharmacotherapy at Winnunga is comparable to the outcomes of mainstream treatment programs. IMPLICATIONS: Opioid replacement pharmacotherapy is beneficial to opioid-dependent Aboriginal people in urban settings. Access to this treatment in culturally appropriate settings needs to be expanded.


Assuntos
Analgésicos Opioides/uso terapêutico , Tratamento Farmacológico , Havaiano Nativo ou Outro Ilhéu do Pacífico , Centros de Tratamento de Abuso de Substâncias , Adulto , Analgésicos Opioides/administração & dosagem , Território da Capital Australiana , Estudos de Coortes , Feminino , Dependência de Heroína/tratamento farmacológico , Humanos , Entrevistas como Assunto , Masculino , Metadona/administração & dosagem , Metadona/uso terapêutico , Avaliação de Resultados em Cuidados de Saúde , Serviços Urbanos de Saúde
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