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111.
Emilie M. M. Santos Wiro J. Niessen Albert J. Yoo Olvert A. Berkhemer Ludo F. Beenen Charles B. Majoie Henk. A. Marquering MR CLEAN investigators 《PloS one》2016,11(1)
Background and Purpose
In acute ischemic stroke (AIS) management, CT-based thrombus density has been associated with treatment success. However, currently used thrombus measurements are prone to inter-observer variability and oversimplify the heterogeneous thrombus composition. Our aim was first to introduce an automated method to assess the entire thrombus density and then to compare the measured entire thrombus density with respect to current standard manual measurements.Materials and Method
In 135 AIS patients, the density distribution of the entire thrombus was determined. Density distributions were described using medians, interquartile ranges (IQR), kurtosis, and skewedness. Differences between the median of entire thrombus measurements and commonly applied manual measurements using 3 regions of interest were determined using linear regression.Results
Density distributions varied considerably with medians ranging from 20.0 to 62.8 HU and IQRs ranging from 9.3 to 55.8 HU. The average median of the thrombus density distributions (43.5 ± 10.2 HU) was lower than the manual assessment (49.6 ± 8.0 HU) (p<0.05). The difference between manual measurements and median density of entire thrombus decreased with increasing density (r = 0.64; p<0.05), revealing relatively higher manual measurements for low density thrombi such that manual density measurement tend overestimates the real thrombus density.Conclusions
Automatic measurements of the full thrombus expose a wide variety of thrombi density distribution, which is not grasped with currently used manual measurement. Furthermore, discrimination of low and high density thrombi is improved with the automated method. 相似文献112.
Florian Pohlig Florian Guell Ulrich Lenze Florian W. Lenze Heinrich M. L. Mühlhofer Johannes Schauwecker Andreas Toepfer Philipp Mayer-Kuckuk Rüdiger von Eisenhart-Rothe Rainer Burgkart Gian M. Salzmann 《PloS one》2016,11(3)
Purpose
In patients with osteoarthritis (OA), intraarticular injection of hyaluronic acid (HA) frequently results in reduced pain and improved function for prolonged periods of time, i.e. more than 6 months. However, the mechanisms underlying these effects are not fully understood. Our underlying hypothesis is that HA modifies the enzymatic breakdown of joint tissues.Methods
To test this hypothesis, we examined osteochondral cylinders from 12 OA patients. In a bioreactor, these samples were stimulated by interleukin 1β (Il1ß) (2 ng/ml) plus mechanical load (2.0 Mpa at 0.5 Hz horizontal and 0.1 Hz vertical rotation), thus the experimental setup recapitulated both catabolic and anabolic clues of the OA joint.Results
Upon addition of HA at either 1 or 3 mg/ml, we observed a significant suppression of expression of metalloproteinase (MMP)-13. A more detailed analysis based on the Kellgren and Lawrence (K&L) OA grade, showed a much greater degree of suppression of MMP-13 expression in grade IV as compared to grade II OA. In contrast to the observed MMP-13 suppression, treatment with HA resulted in a suppression of MMP-1 expression only at 1 mg/ml HA, while MMP-2 expression was not significantly affected by either HA concentration.Conclusion
Together, these data suggest that under concurrent catabolic and anabolic stimulation, HA exhibits a pronounced suppressive effect on MMP-13. In the long-run these findings may benefit the development of treatment strategies aimed at blocking tissue degradation in OA patients. 相似文献113.
Background
Physical activity (PA) is a well-known and underused protective factor for numerous health outcomes, and interventions are hampered by lack of objective data. We combined accelerometers with diaries to estimate the contributions to total activity from different domains throughout the day and week in adolescents.Methods
Accelerometric and diary data from 1403 adolescents (45% male, mean age 15.6 ± 0.5 years) were combined to evaluate daily levels and domains of sedentary, light, and moderate-to-vigorous activity (MVPA) during a typical week. Freedson’s cutoff points were applied to determine levels of activity. Total activity was broken down into school physical education (PE), school outside PE, transportation to school, sport, and other time.Results
About 2/3 of adolescents’ time was spent sedentary, 1/3 in light activity, and about 5% in MVPA. Boys and girls averaged 46 (SD 22) and 38 (23) minutes MVPA per day. Adolescents were most active during leisure sport, spending about 30% of it in MVPA, followed by PE (about 20%) transport to school (14%) and either school class time or other time (3%). PE provided 5% of total MVPA, while leisure sport provided 16% and transportation to school 8%. School was the most sedentary part of the day with over 75% of time outside PE spent sedentary.Conclusions
These German adolescents were typical of Europeans in showing low levels of physical activity, with significant contributions from leisure sport, transportation and school PE. Leisure sport was the most active part of the day, and participation did not vary significantly by sex, study center (region of Germany) or BMI. Transportation to school was frequent and thus accounted for a significant fraction of total MVPA. This indicates that even in a population with good access to dedicated sporting activities, frequent active transportation can add significantly to total MVPA. 相似文献114.
Day vs. night predation on artificial caterpillars in primary rainforest habitats – an experimental approach
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Carlo L. Seifert Christian H. Schulze Tobias C. T. Dreschke Heinrich Frötscher Konrad Fiedler 《Entomologia Experimentalis et Applicata》2016,158(1):54-59
The influence of natural enemies has led to the evolution of various predator avoidance strategies in herbivorous insects. Many caterpillars are exclusively active at night and rest during the day. It is widely assumed that nocturnal activity in caterpillars reduces their risk of falling prey to their natural enemies. To test this hypothesis, we compared predation pressure between day and night in tree‐fall gaps and closed‐canopy forest sites in an Amazonian primary lowland rainforest. Artificial clay caterpillars, showing camouflaged colouration (green), were exposed as potential prey to a natural predator community. Attacks were significantly more frequent during daytime and were reduced by about a quarter at night in tree‐fall gaps, and by a third in closed‐canopy forest sites. This supports the idea of time‐dependent activity in caterpillars as an antipredatory adaptation. Further, independent of the time of day, predation pressure on caterpillars was significantly higher in tree‐fall gaps compared to closed‐canopy forest habitats. Nearly all predation events were caused by arthropods, whereas birds played a negligible role. Across both habitat types and time scales, ants acted as major predator group, emphasising their important role in population control of herbivorous insects in lowland rainforest ecosystems. This is the first experimental study using artificial caterpillars to examine whether time‐scheduling of exposition might influence predation risk amongst undefended, solitary, free‐living lepidopteran larvae. 相似文献
115.
Surface polysaccharides and quorum sensing are involved in the attachment and survival of Xanthomonas albilineans on sugarcane leaves
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Imene Mensi Jean‐Heinrich Daugrois Isabelle Pieretti Daniel Gargani Laura A. Fleites Julie Noell Francois Bonnot Dean W. Gabriel Philippe Rott 《Molecular Plant Pathology》2016,17(2):236-246
Xanthomonas albilineans, the causal agent of sugarcane leaf scald, is a bacterial plant pathogen that is mainly spread by infected cuttings and contaminated harvesting tools. However, some strains of this pathogen are known to be spread by aerial means and are able to colonize the phyllosphere of sugarcane before entering the host plant and causing disease. The objective of this study was to identify the molecular factors involved in the survival or growth of X. albilineans on sugarcane leaves. We developed a bioassay to test for the attachment of X. albilineans on sugarcane leaves using tissue‐cultured plantlets grown in vitro. Six mutants of strain XaFL07‐1 affected in surface polysaccharide production completely lost their capacity to survive on the sugarcane leaf surface. These mutants produced more biofilm in vitro and accumulated more cellular poly‐β‐hydroxybutyrate than the wild‐type strain. A mutant affected in the production of small molecules (including potential biosurfactants) synthesized by non‐ribosomal peptide synthetases (NRPSs) attached to the sugarcane leaves as well as the wild‐type strain. Surprisingly, the attachment of bacteria on sugarcane leaves varied among mutants of the rpf gene cluster involved in bacterial quorum sensing. Therefore, quorum sensing may affect polysaccharide production, or both polysaccharides and quorum sensing may be involved in the survival or growth of X. albilineans on sugarcane leaves. 相似文献
116.
Nihal Kenawy Helen Kalirai Joseph J. Sacco Sarah L. Lake Steffen Heegaard Ann‐Cathrine Larsen Paul T. Finger Tatyana Milman Kimberly Chin Carlo Mosci Francesco Lanza Alexandre Moulin Caroline A. Schmitt Jean Pierre Caujolle Clia Maschi Marina Marinkovic Azzam F. Taktak Heinrich Heimann Bertil E. Damato Sarah E. Coupland 《Pigment cell & melanoma research》2019,32(4):564-575
Relatively little is known about the genetic aberrations of conjunctival melanomas (CoM) and their correlation with clinical and histomorphological features as well as prognosis. The aim of this large collaborative multicenter study was to determine potential key biomarkers for metastatic risk and any druggable targets for high metastatic risk CoM. Using Affymetrix single nucleotide polymorphism genotyping arrays on 59 CoM, we detected frequent amplifications on chromosome (chr) 6p and deletions on 7q, and characterized mutation‐specific copy number alterations. Deletions on chr 10q11.21‐26.2, a region harboring the tumor suppressor genes, PDCD4, SUFU, NEURL1, PTEN, RASSF4, DMBT1, and C10orf90 and C10orf99, significantly correlated with metastasis (Fisher's exact, p ≤ 0.04), lymphatic invasion (Fisher's exact, p ≤ 0.02), increasing tumor thickness (Mann–Whitney, p ≤ 0.02), and BRAF mutation (Fisher's exact, p ≤ 0.05). This enhanced insight into CoM biology is a step toward identifying patients at risk of metastasis and potential therapeutic targets for systemic disease. 相似文献
117.
118.
Fewou SN Ramakrishnan H Büssow H Gieselmann V Eckhardt M 《The Journal of biological chemistry》2007,282(22):16700-16711
Oligodendrocyte precursor cells modify the neural cell adhesion molecule (NCAM) by the attachment of polysialic acid (PSA). Upon further differentiation into mature myelinating oligodendrocytes, however, oligodendrocyte precursor cells down-regulate PSA synthesis. In order to address the question of whether this down-regulation is a necessary prerequisite for the myelination process, transgenic mice expressing the polysialyltransferase ST8SiaIV under the control of the proteolipid protein promoter were generated. In these mice, postnatal down-regulation of PSA in oligodendrocytes was abolished. Most NCAM-120, the characteristic NCAM isoform in oligodendrocytes, carried PSA in the transgenic mice at all stages of postnatal development. Polysialylated NCAM-120 partially co-localized with myelin basic protein and was present in purified myelin. The permanent expression of PSA-NCAM in oligodendrocytes led to a reduced myelin content in the forebrains of transgenic mice during the period of active myelination and in the adult animal. In situ hybridizations indicated a significant decrease in the number of mature oligodendrocytes in the forebrain. Thus, down-regulation of PSA during oligodendrocyte differentiation is a prerequisite for efficient myelination by mature oligodendrocytes. Furthermore, myelin of transgenic mice exhibited structural abnormalities like redundant myelin and axonal degeneration, indicating that the down-regulation of PSA is also necessary for myelin maintenance. 相似文献
119.
Leipold E DeBie H Zorn S Borges A Olivera BM Terlau H Heinemann SH 《Channels (Austin, Tex.)》2007,1(4):253-262
The muO-conotoxins MrVIA and MrVIB are 31-residue peptides from Conus marmoreus, belonging to the O-superfamily of conotoxins with three disulfide bridges. They have attracted attention because they are inhibitors of tetrodotoxin-insensitive voltage-gated sodium channels (Na(V)1.8) and could therefore serve as lead structure for novel analgesics. The aim of this study was to elucidate the molecular mechanism by which muO-conotoxins affect Na(V) channels. Rat Na(V)1.4 channels and mutants thereof were expressed in mammalian cells and were assayed with the whole-cell patch-clamp method. Unlike for the M-superfamily mu-conotoxin GIIIA from Conus geographus, channel block by MrVIA was strongly diminished after activating the Na(V) channels by depolarizing voltage steps. Searching for the source of this voltage dependence, the gating charges in all four-voltage sensors were reduced by site-directed mutagenesis showing that alterations of the voltage sensor in domain-2 have the strongest impact on MrVIA action. These results, together with previous findings that the effect of MrVIA depends on the structure of the pore-loop in domain-3, suggest a functional similarity with scorpion beta-toxins. In fact, MrVIA functionally competed with the scorpion beta-toxin Ts1 from Tityus serrulatus, while it did not show competition with mu-GIIIA. Ts1 and mu-GIIIA did not compete either. Thus, similar to scorpion beta-toxins, muO-conotoxins are voltage-sensor toxins targeting receptor site-4 on Na(V) channels. They "block" Na(+) flow most likely by hindering the voltage sensor in domain-2 from activating and, hence, the channel from opening. 相似文献
120.
How HIV-1 hijacks ALIX 总被引:1,自引:0,他引:1
Göttlinger HG 《Nature structural & molecular biology》2007,14(4):254-256