52 research outputs found
Thyroid and pituitary gland development from hatching through metamorphosis of a teleost flatfish, the Atlantic halibut
Fish larval development, not least the spectacular
process of flatfish metamorphosis, appears to be
under complex endocrine control, many aspects of
which are still not fully elucidated. In order to obtain
data on the functional development of two major
endocrine glands, the pituitary and the thyroid, during
flatfish metamorphosis, histology, immunohistochemistry
and in situ hybridization techniques were applied on
larvae of the Atlantic halibut (Hippoglossus hippoglossus),
a large, marine flatfish species, from hatching
through metamorphosis. The material was obtained
from a commercial hatchery. Larval age is defined as
day-degrees (D =accumulated daily temperature from
hatching). Sporadic thyroid follicles are first detected in
larvae at 142 D (27 days post-hatch), prior to the
completion of yolk sack absorption. Both the number
and activity of the follicles increase markedly after yolk
sack absorption and continue to do so during subsequent
development. The larval triiodothyronine (T3)
and thyroxine (T4) content increases, subsequent to yolk
absorption, and coincides with the proliferation of thyroid
follicles. A second increase of both T3 and T4 occurs
around the start of metamorphosis and the T3 content
further increases at the metamorphic climax. Overall,
the T3 content is lower than T4. The pituitary gland can
first be distinguished as a separate organ at the yolk sack
stage. During subsequent development, the gland becomes
more elongated and differentiates into neurohypophysis (NH), pars distalis (PD) and pars intermedia
(PI). The first sporadic endocrine pituitary cells are observed
at the yolk sack stage, somatotrophs (growth
hormone producing cells) and somatolactotrophs (somatolactin
producing cells) are first observed at 121 D
(23 days post-hatch), and lactotrophs (prolactin producing
cells) at 134 D (25 days post-hatch). Scarce
thyrotrophs are evident after detection of the first thyroid
follicles (142 D ), but coincident with a phase in
which follicle number and activity increase (260 D ).
The somatotrophs are clustered in the medium ventral
region of the PD, lactotrophs in the anterior part of the
PD and somatolactotrophs are scattered in the mid and
posterior region of the pituitary. At around 600 D ,
coinciding with the start of metamorphosis, somatolactotrophs
are restricted to the interdigitating tissue of the
NH. During larval development, the pituitary endocrine
cells become more numerous. The present data on thyroid
development support the notion that thyroid hormones
may play a significant role in Atlantic halibut
metamorphosis. The time of appearance and the subsequent
proliferation of pituitary somatotrophs, lactotrophs,
somatolactotrophs and thyrotrophs indicate at
which stages of larval development and metamorphosis
these endocrine cells may start to play active regulatory
roles.This work has been carried out within the
projects ‘‘Endocrine Control as a Determinant of Larval Quality in
Fish Aquaculture’’ (CT-96-1422) and ‘‘Arrested development: The
Molecular and Endocrine Basis of Flatfish Metamorphosis’’
(Q5RS-2002-01192), with financial support from the Commission
of the European Communities. However, it does not necessarily
reflect the Commission’s views and in no way anticipates its future
policy in this area. This project was further supported by the
Swedish Council for Agricultural and Forestry Research and Pluriannual
funding to CCMAR by the Portuguese Science and
Technology Council
Natriuretic peptides and integrated risk assessment for cardiovascular disease: an individual-participant-data meta-analysis
BACKGROUND: Guidelines for primary prevention of cardiovascular diseases focus on prediction of coronary heart disease and stroke. We assessed whether or not measurement of N-terminal-pro-B-type natriuretic peptide (NT-proBNP) concentration could enable a more integrated approach than at present by predicting heart failure and enhancing coronary heart disease and stroke risk assessment.
METHODS: In this individual-participant-data meta-analysis, we generated and harmonised individual-participant data from relevant prospective studies via both de-novo NT-proBNP concentration measurement of stored samples and collection of data from studies identified through a systematic search of the literature (PubMed, Scientific Citation Index Expanded, and Embase) for articles published up to Sept 4, 2014, using search terms related to natriuretic peptide family members and the primary outcomes, with no language restrictions. We calculated risk ratios and measures of risk discrimination and reclassification across predicted 10 year risk categories (ie, <5%, 5% to <7·5%, and ≥7·5%), adding assessment of NT-proBNP concentration to that of conventional risk factors (ie, age, sex, smoking status, systolic blood pressure, history of diabetes, and total and HDL cholesterol concentrations). Primary outcomes were the combination of coronary heart disease and stroke, and the combination of coronary heart disease, stroke, and heart failure.
FINDINGS: We recorded 5500 coronary heart disease, 4002 stroke, and 2212 heart failure outcomes among 95 617 participants without a history of cardiovascular disease in 40 prospective studies. Risk ratios (for a comparison of the top third vs bottom third of NT-proBNP concentrations, adjusted for conventional risk factors) were 1·76 (95% CI 1·56-1·98) for the combination of coronary heart disease and stroke and 2·00 (1·77-2·26) for the combination of coronary heart disease, stroke, and heart failure. Addition of information about NT-proBNP concentration to a model containing conventional risk factors was associated with a C-index increase of 0·012 (0·010-0·014) and a net reclassification improvement of 0·027 (0·019-0·036) for the combination of coronary heart disease and stroke and a C-index increase of 0·019 (0·016-0·022) and a net reclassification improvement of 0·028 (0·019-0·038) for the combination of coronary heart disease, stroke, and heart failure.
INTERPRETATION: In people without baseline cardiovascular disease, NT-proBNP concentration assessment strongly predicted first-onset heart failure and augmented coronary heart disease and stroke prediction, suggesting that NT-proBNP concentration assessment could be used to integrate heart failure into cardiovascular disease primary prevention.
FUNDING: British Heart Foundation, Austrian Science Fund, UK Medical Research Council, National Institute for Health Research, European Research Council, and European Commission Framework Programme 7
Dissecting the Shared Genetic Architecture of Suicide Attempt, Psychiatric Disorders, and Known Risk Factors
Background Suicide is a leading cause of death worldwide, and nonfatal suicide attempts, which occur far more frequently, are a major source of disability and social and economic burden. Both have substantial genetic etiology, which is partially shared and partially distinct from that of related psychiatric disorders. Methods We conducted a genome-wide association study (GWAS) of 29,782 suicide attempt (SA) cases and 519,961 controls in the International Suicide Genetics Consortium (ISGC). The GWAS of SA was conditioned on psychiatric disorders using GWAS summary statistics via multitrait-based conditional and joint analysis, to remove genetic effects on SA mediated by psychiatric disorders. We investigated the shared and divergent genetic architectures of SA, psychiatric disorders, and other known risk factors. Results Two loci reached genome-wide significance for SA: the major histocompatibility complex and an intergenic locus on chromosome 7, the latter of which remained associated with SA after conditioning on psychiatric disorders and replicated in an independent cohort from the Million Veteran Program. This locus has been implicated in risk-taking behavior, smoking, and insomnia. SA showed strong genetic correlation with psychiatric disorders, particularly major depression, and also with smoking, pain, risk-taking behavior, sleep disturbances, lower educational attainment, reproductive traits, lower socioeconomic status, and poorer general health. After conditioning on psychiatric disorders, the genetic correlations between SA and psychiatric disorders decreased, whereas those with nonpsychiatric traits remained largely unchanged. Conclusions Our results identify a risk locus that contributes more strongly to SA than other phenotypes and suggest a shared underlying biology between SA and known risk factors that is not mediated by psychiatric disorders.Peer reviewe
Novel Methods for Surface EMG Analysis and Exploration Based on Multi-Modal Gaussian Mixture Models
<div><p>This paper introduces a new method for data analysis of animal muscle activation during locomotion. It is based on fitting Gaussian mixture models (GMMs) to surface EMG data (sEMG). This approach enables researchers/users to isolate parts of the overall muscle activation within locomotion EMG data. Furthermore, it provides new opportunities for analysis and exploration of sEMG data by using the resulting Gaussian modes as atomic building blocks for a hierarchical clustering. In our experiments, composite peak models representing the general activation pattern per sensor location (one sensor on the long back muscle, three sensors on the gluteus muscle on each body side) were identified per individual for all 14 horses during walk and trot in the present study. Hereby we show the applicability of the method to identify composite peak models, which describe activation of different muscles throughout cycles of locomotion.</p></div
Characterization of a dynamic metabolon producing the defense compound dhurrin in sorghum
Metabolite channeling by a dynamic metabolon
The specialized metabolite dhurrin breaks down into cyanide when plant cell walls have been chewed, deterring insect pests. Laursen
et al.
found that the enzymes that synthesize dhurrin in sorghum assemble as a metabolon in lipid membranes (see the Perspective by Dsatmaichi and Facchini). The dynamic nature of metabolon assembly and disassembly provides dhurrin on an as-needed basis. Membrane-anchored cytochrome P450s cooperated with a soluble glucosyltransferase to channel intermediates toward efficient dhurrin production.
Science
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890
; see also p.
829
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