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排序方式: 共有112条查询结果,搜索用时 15 毫秒
61.
Claude R. Joiris Eva Falck Diederik D’Hert Simon Jungblut Karin Boos 《Polar Biology》2014,37(11):1645-1657
The distribution at sea of upper trophic levels—seabirds and marine mammals—is depending on their food availability: high concentrations reflect high prey abundance and thus high biological production. Polar marine ecosystems are characterized by low biodiversity and high biological patchiness. The distribution of predators, as a consequence, shows a similar patchiness. During two expeditions of icebreaking RV Polarstern in June–July 2011, biodiversity in the arctic marine zone north of 70°N was very low, with low numbers of species: 20 seabirds, eight cetaceans, five pinnipeds and polar bear. Moreover, a few species accounted for the majority in numbers: four bird species for 95 % of the total of 23,000 seabirds recorded during 700 transect counts: fulmar Fulmarus glacialis, kittiwake Rissa tridactyla, Brünnich’s guillemot Uria lomvia and little auk Alle alle. Among the marine mammals, 250 fin whales Balaenoptera physalus accounted for 80 % of the identified large cetaceans, 270 white-beaked dolphin Lagenorhynchus albirostris for 100 % of the small cetaceans and 180 harp seals Pagophilus groenlandica for 80 % of the identified pinnipeds. Their quantitative distribution was depending on water masses and oceanic fronts, large cetaceans—mainly fin whales—showing an important aggregation on the shelf slope off western Spitsbergen, as well as little auks and Brünnich’s guillemots. So that this zone, shelf slope and front of mixed Arctic/Atlantic Waters, showed unusually high seabird and cetacean concentrations. Seasonal factors possibly influencing their distribution are addressed. 相似文献
62.
Davy Vancampfort Joseph Firth Christoph U. Correll Marco Solmi Dan Siskind Marc De Hert Rebekah Carney Ai Koyanagi Andr F. Carvalho Fiona Gaughran Brendon Stubbs 《World psychiatry》2019,18(1):53-66
We summarized and compared meta‐analyses of pharmacological and non‐pharmacological interventions targeting physical health outcomes among people with schizophrenia spectrum disorders. Major databases were searched until June 1, 2018. Of 3,709 search engine hits, 27 meta‐analyses were included, representing 128 meta‐analyzed trials and 47,231 study participants. While meta‐analyses were generally of adequate or high quality, meta‐analyzed studies were less so. The most effective weight reduction interventions were individual lifestyle counseling (standardized mean difference, SMD=–0.98) and exercise interventions (SMD=–0.96), followed by psychoeducation (SMD=–0.77), aripiprazole augmentation (SMD=–0.73), topiramate (SMD=–0.72), d‐fenfluramine (SMD=–0.54) and metformin (SMD=–0.53). Regarding waist circumference reduction, aripiprazole augmentation (SMD=–1.10) and topiramate (SMD=–0.69) demonstrated the best evidence, followed by dietary interventions (SMD=–0.39). Dietary interventions were the only to significantly improve (diastolic) blood pressure (SMD=–0.39). Switching from olanzapine to quetiapine or aripiprazole (SMD=–0.71) and metformin (SMD=–0.65) demonstrated best efficacy for reducing glucose levels, followed by glucagon‐like peptide‐1 receptor agonists (SMD=–0.39), dietary interventions (SMD=–0.37) and aripiprazole augmentation (SMD=–0.34), whereas insulin resistance improved the most with metformin (SMD=–0.75) and rosiglitazone (SMD=–0.44). Topiramate had the greatest efficacy for triglycerides (SMD=–0.68) and low‐density lipoprotein (LDL)‐cholesterol (SMD=–0.80), whereas metformin had the greatest beneficial effects on total cholesterol (SMD=–0.51) and high‐density lipoprotein (HDL)‐cholesterol (SMD=0.45). Lifestyle interventions yielded small effects for triglycerides, total cholesterol and LDL‐cholesterol (SMD=–0.35 to –0.37). Only exercise interventions increased exercise capacity (SMD=1.81). Despite frequent physical comorbidities and premature mortality mainly due to these increased physical health risks, the current evidence for pharmacological and non‐pharmacological interventions in people with schizophrenia to prevent and treat these conditions is still limited and more larger trials are urgently needed. 相似文献
63.
Divya T. Kandala Nimmy Mohan Vivekanand A Sudheesh AP Reshmi G Rakesh S. Laishram 《Nucleic acids research》2016,44(2):811-823
Almost all eukaryotic mRNAs have a poly (A) tail at the 3′-end. Canonical PAPs (PAPα/γ) polyadenylate nuclear pre-mRNAs. The recent identification of the non-canonical Star-PAP revealed specificity of nuclear PAPs for pre-mRNAs, yet the mechanism how Star-PAP selects mRNA targets is still elusive. Moreover, how Star-PAP target mRNAs having canonical AAUAAA signal are not regulated by PAPα is unclear. We investigate specificity mechanisms of Star-PAP that selects pre-mRNA targets for polyadenylation. Star-PAP assembles distinct 3′-end processing complex and controls pre-mRNAs independent of PAPα. We identified a Star-PAP recognition nucleotide motif and showed that suboptimal DSE on Star-PAP target pre-mRNA 3′-UTRs inhibit CstF-64 binding, thus preventing PAPα recruitment onto it. Altering 3′-UTR cis-elements on a Star-PAP target pre-mRNA can switch the regulatory PAP from Star-PAP to PAPα. Our results suggest a mechanism of poly (A) site selection that has potential implication on the regulation of alternative polyadenylation. 相似文献
64.
H Arslan A Aktaş E Elibol OBB Esener AP Türkmen KK Yurt 《Biotechnic & histochemistry》2016,91(4):277-282
Diclofenac sodium (DS) is used primarily to treat fever and to alleviate pain and inflammation. We investigated the effects of DS exposure during gestation on the testes of rat pups to investigate the safety of its use during the prenatal period. Pregnant rats were separated into control, saline, low dose, medium dose and high dose groups. DS was given between weeks 15 and 21 of gestation. Total numbers of spermatogonia and Sertoli cells were counted in the testes of 7-day-old male rats using the physical disector method. By the end of the study, the total number of Sertoli cells was decreased significantly in a dose dependent manner in the medium and high dose groups compared to controls. No significant differences were found in the total number of spermatogonia in the control, saline and low dose DS groups. Medium and high dose DS administration reduced the total number of spermatogonia compared to other groups. We suggest that prenatal administration of DS can cause deleterious effects on the testis development, especially in high doses. 相似文献
65.
K Vandepitte AS Gristina K DE Hert T Meekers I Roldán-Ruiz O Honnay 《Molecular ecology》2012,21(17):4206-4215
Colonization is crucial to habitat restoration projects that rely on the spontaneous regeneration of the original vegetation. However, as a previously declining plant species spreads again, the likelihood of founder effects increases through recurrent population founding and associated serial bottlenecks. We related Amplified Fragment Length Polymorphism markers genetic variation and fitness to colonization history for all extant populations of the outcrossing terrestrial orchid Dactylorhiza incarnata in an isolated coastal dune complex. Around 1970, D. incarnata suffered a severe bottleneck yet ultimately persisted and gradually spread throughout the spatially segregated dune slacks, aided by the restoration of an open vegetation. Genetic assignment demonstrated dispersal to vacant sites from few nearby extant populations and very limited inflow from outside the spatially isolated reserve. Results further indicated that recurrent founding from few local sources resulted in the loss of genetic diversity and promoted genetic divergence (FST = 0.35) among populations, but did not influence population fitness. The few source populations initially available and the limited inflow of genes from outside the study reserve, as a consequence of habitat degradation and spatial isolation, may have magnified the genetic effects of recurrent population founding. 相似文献
66.
Papakonstantinou E; Karakiulakis G; Eickelberg O; Perruchoud AP; Block LH; Roth M 《Glycobiology》1998,8(8):821-830
The formation of atherosclerotic lesions is characterized by invasion of
vascular smooth muscle cells (VSMC) into the tunica intima of the arterial
wall and subsequently by increased proliferation of VSMC, a process
apparently restricted to the intimal layer of blood vessels. Both events
are preceded by the pathological overexpression of several growth factors,
such as platelet-derived growth factor (PDGF) which is a potent mitogen for
VSMC and can induce their chemotaxis. PDGF is generally not expressed in
the normal artery but it is upregulated in atherosclerotic lesions. We have
previously shown that PDGF-BB specifically stimulates proliferating VSMC to
secrete a 340 kDa hyaluronic acid (HA-340). Here, we present evidence
regarding the biological functions of this glycan. We observed that HA-340
inhibited the PDGF-induced proliferation of human VSMC in a dose-dependent
manner and enhanced the PDGF-dependent invasion of VSMC through a basement
membrane barrier. These effects were abolished following treatment of
HA-340 with hyaluronidase. The effect of HA-340 on the PDGF-dependent
invasion of VSMC coincided with increased secretion of the 72-kDa type IV
collagenase by VSMC and was completely blocked by GM6001, a hydroxamic acid
inhibitor of matrix metalloproteinases. HA-340 did not exert any
chemotactic potency, nor did it affect chemotaxis of VSMC along a PDGF
gradient. In human atheromatic aortas, we found that HA- 340 is expressed
with a negative concentration gradient from the tunica media to the tunica
intima and the atheromatic plaque. Our findings suggest that HA-340 may be
linked to the pathogenesis of atherosclerosis, by modulating VSMC
proliferation and invasion.
相似文献
67.
68.
S Çolakoğlu A Aktaş S Raimondo AP Türkmen BZ Altunkaynak E Odacı 《Biotechnic & histochemistry》2014,89(2):136-144
We investigated the effects of diclofenac sodium (DS) on development of the optic nerve in utero. Pregnant female rats were separated into three groups: control, saline treated and DS treated. Offspring of these animals were divided into 4-week-old and 20-week-old groups. At the end of the 4th and 20th weeks of postnatal life, the animals were sacrificed, and right optic nerves were excised and sectioned for ultrastructural and stereological analyses. We demonstrated that both DS and saline produced structural and morphometric changes in the total axon number and density of axons, but decreased the myelin sheath thickness in male optic nerves. All ultrastructural and morphometric features were well developed in 20-week-old rats. We showed that development of the optic nerve continues during the early postnatal period and that some compensation for exposure to deleterious agents in utero may occur during early postnatal life. 相似文献
69.
70.