Introduction Parkinson's disease (PD) is one of the most common neurodegenerative disorders. Sources of data Literature search using Medline with keywords Parkinson's disease supplemented with ...previously published papers known to the author. Areas of agreement There have been significant recent advances in the understanding of the pathogenesis of the disease. There has also been a greater realization that the disorder may be associated with significant non-motor disturbances in addition to the more commonly recognized motor complications. Areas of controversy Although there is growing circumstantial evidence, it remains to be proven whether any of the current treatments for PD have a neuroprotective effect. Areas timely for developing research Although there is no cure, there are several management options for the early treatment of PD. As the disease progresses, further treatment options are available; however, the management of late-stage motor complications and non-motor symptoms remains particularly challenging and will benefit from further clinical research.
Seasonality is an important adaptive trait in temperate fish species as it entrains or regulates most physiological events such as reproductive cycle, growth profile, locomotor activity and key ...life‐stage transitions. Photoperiod is undoubtedly one of the most predictable environmental signals that can be used by most living organisms including fishes in temperate areas. This said, however, understanding of how such a simple signal can dictate the time of gonadal recruitment and spawning, for example, is a complex task. Over the past few decades, many scientists attempted to unravel the roots of photoperiodic signalling in teleosts by investigating the role of melatonin in reproduction, but without great success. In fact, the hormone melatonin is recognized as the biological time‐keeping hormone in fishes mainly due to the fact that it reflects the seasonal variation in daylength across the whole animal kingdom rather than the existence of direct evidences of its role in the entrainment of reproduction in fishes. Recently, however, some new studies clearly suggested that melatonin interacts with the reproductive cascade at a number of key steps such as through the dopaminergic system in the brain or the synchronization of the final oocyte maturation in the gonad. Interestingly, in the past few years, additional pathways have become apparent in the search for a fish photoneuroendocrine system including the clock‐gene network and kisspeptin signalling and although research on these topics are still in their infancy, it is moving at great pace. This review thus aims to bring together the current knowledge on the photic control of reproduction mainly focusing on seasonal temperate fish species and shape the current working hypotheses supported by recent findings obtained in teleosts or based on knowledge gathered in mammalian and avian species. Four of the main potential regulatory systems (light perception, melatonin, clock genes and kisspeptin) in fish reproduction are reviewed.
Primordial germ cells (PGCs) are specified by maternally provided determinants in fish. PGCs migrate then into prospective gonadal sites during early development and give rise to germ cell lineage. ...PGC disrupted animals do not sexually mature which has a range of commercial as well as environmental benefits. To find potential target genes for sterilisation of Nile tilapia, relative mRNA abundance patterns and tissue distribution of four nanos, two piwil, dnd1, vasa and three pum genes were investigated during ontogenic development from unfertilised eggs to newly hatched larvae and in adult tissues, respectively. The ontogenic pattern of RNA abundance revealed that all the investigated gene transcripts are maternally deposited to varying degrees, except for nanos2 which is not expressed in eggs. The ontogenic patterns of relative RNA abundance could be grouped into three categories. The first one, including nanos3, piwil1, piwil2, dnd1 and vasa, showed abundant transcript levels during early developmental stages which are then degraded during the period of maternal to zygotic transition between blastula and gastrula stages with a reduction in expression of four to five orders of magnitude by hatching stage. Another, including pum2 and pum3, showed similar patterns to the first group, but the transcript levels are reduced by only two orders of magnitude. The third group, including nanos1a, nanos1b and pum1, was characterised by a zygotic increase. nanos2 had no detectable transcripts until hatching stage. The tissue screening of nanos1a, nanos1b, pum1, pum2 and pum3 showed that they are expressed in various tissues, implying their potential pleiotropic effects in these tissues apart from gonads. In contrast, nanos3, piwil1, piwil2, dnd1 and vasa appeared to be exclusively expressed in gonads (both ovary and testis), and nanos2 showed testis-specific expression. Based on these results nanos3, piwil1, piwil2, dnd1 and vasa were prioritised among the 11 selected genes as potential target genes for sterilisation in Nile tilapia as they have no significant zygotic expression during embryogenesis, they are expressed exclusively in gonads and maternally deposited. These features suggest a potential role of these genes in the specification and maintenance of PGCs during the ontogenic development of Nile tilapia.
•Three different patterns of transcript expression were found (11 genes screened).•Gonad specificity and ontogenic pattern revealed maternally deposited germline genes.•New potential target genes (piwil) were prioritised for gene editing in Nile tilapia.
Light is a key environmental factor that synchronizes all life-stages of fish, from embryo development to sexual maturation. The underwater photo-environment is complex since light characteristics ...(i.e. intensity, photoperiod and spectrum) depend on the absorbance properties of the water column. The aim of this paper is to review the effects of artificial lighting conditions on the performance, development and welfare of some fish larvae of commercial interest. Reviewed results show that larvae were significantly affected by light characteristics. For example, European sea bass and sole larvae achieved the best performance, and showed fastest development and lowest degree of deformity under a light/dark cycle using blue light (half-peak bandwidth
=
435–500
nm), conditions which were the closest to their natural aquatic environment. However, constant light (LL) or constant darkness (DD) was shown to negatively affect normal larval development and resulted in increased malformations and poor survival in most of the studied species. Similar results have been observed in other fish larvae such as Atlantic cod, which performed better under short wavelengths (blue and green). These findings highlight the role of lighting conditions during the early development of fish larvae and should be taken into account for the optimization of rearing protocols in fish hatcheries as juvenile supply is one of the main production bottlenecks.
We give a new bound ω < 2.37369 for the exponent of complexity of matrix multiplication, giving a small improvement on the previous bound obtained by Coppersmith and Winograd. The proof involves an ...extension of the method used by these authors. We have attempted to make the exposition self-contained.
The use of synthetic peptides as effective asymmetric catalysts is discussed. The modular nature of peptides allows for alteration of reactivity and selectivity.
We develop an asymptotic expansion for small time of the density of the solution of a non-degenerate system of stochastic differential equations with smooth coefficients, and apply this to the ...stepwise approximation of solutions. The asymptotic expansion, which takes the form of a multivariate Edgeworth-type expansion, is obtained from the Kolmogorov forward equation using some standard PDE results. To generate one step of the approximation to the solution, we use a Cornish–Fisher type expansion derived from the Edgeworth expansion. To interpret the approximation generated in this way as a strong approximation we use couplings between the (normal) random variables used and the Brownian path driving the SDE. These couplings are constructed using techniques from optimal transport and Vaserstein metrics. The type of approximation so obtained may be regarded as intermediate between a conventional strong approximation and a weak approximation. In principle approximations of any order can be obtained, though for higher orders the algebra becomes very heavy. In order 1/2 the method gives the usual Euler approximation; in order 1 it gives a variant of the Milstein method, but which needs only normal variables to be generated. However the method is somewhat limited by the non-degeneracy requirement.
Evidence from mammals and aves alludes to a possibly conserved seasonal photoperiod induced neuroendocrine cascade which stimulates subsequent sexual maturation however our understanding of this ...mechanism in teleosts is lacking. Unlike all teleosts studied to date, the Atlantic cod (Gadus morhua) is a short day breeder with the reduction in day-length from the summer solstice stimulating gametogenesis. Cod specific orthologues of eya3, tshβ and dio2 were identified and their expression was monitored in the brain and pituitary of cod held under either stimulated or inhibited photoperiod conditions. While no differential expression was apparent in brain dio2 &tshβ and pituitary tshβ, there was significant temporal variation in expression of pituitary eya3 under the SNP treatment, with expression level elevating in association with active gametogenesis. Under the LL treatment, sexual maturation was inhibited and there was a corresponding suppression of eya3 expression. In a second study the impact of size/energetic status on the initiation of sexual maturation was investigated. In the feed restricted population maturation was significantly suppressed (5% sexually mature) compared to the ab libitum fed stock (95% sexually mature) with there being a concomitant significant suppression in pituitary eya3 expression. Overall, these results suggest that pituitary eya3 has the potential to act as an integrator of both environmental and energetic regulation of sexual maturation of cod. Being the first account of eya3 induction in a short day breeding teleost, the conserved association with stimulation of reproduction and not seasonal state indicates that the upstream drivers which initiate the pathway differ among vertebrates according to their breeding strategies, but the pathway itself and its role in the reproductive cascade appears to be conserved across the vertebrate clade.
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•Evidence of conservation of the PNES across the vertebrate clade.•Eya3 exhibits a strong seasonal expression pattern which is photoperiod sensitive•First evidence of nutritional regulation of Eya3 expression associated with maturation
Stroke and pregnancy Davie, C A; O'Brien, P
Journal of neurology, neurosurgery and psychiatry,
03/2008, Letnik:
79, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Pregnancy-related stroke is, fortunately, a rare event. However, when it occurs, there may be implications for management of the patient and delivery of the child. This article reviews the mechanisms ...and risk factors for stroke related to pregnancy, the presenting features, diagnosis and management of the different stroke types, and the implications for pregnancy and delivery.
Highlights ► qPCR assays for kisspeptins, GnRHs, gonadotropins were developed in sea bass. ► Seasonal mRNA profiles in male repeat spawner were analysed. ► Clear seasonal profiles for kiss1 , kiss2 ...and kissr4 mRNAs were shown. ► Kissr4 , fshβ and lhβ mRNA levels increased gradually and peaked during spermatogenesis. ► kiss1 , kiss2 , cGnRHII as well as steroids showed peaks during early spawning.
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