903 resultados para Indirectly affects
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BACKGROUND: Excessive and abnormal accumulation of alpha-synuclein (α-synuclein) is a factor contributing to pathogenic cell death in Parkinson's disease. The purpose of this study, based on earlier observations of Parkinson's disease cerebrospinal fluid (PD-CSF) initiated cell death, was to determine the effects of CSF from PD patients on the functionally different microglia and astrocyte glial cell lines. Microglia cells from human glioblastoma and astrocytes from fetal brain tissue were cultured, grown to confluence, treated with fixed concentrations of PD-CSF, non-PD disease control CSF, or control no-CSF medium, then photographed and fluorescently probed for α-synuclein content by deconvolution fluorescence microscopy. Outcome measures included manually counted cell growth patterns from day 1-8; α-synuclein density and distribution by antibody tagged 3D model stacked deconvoluted fluorescent imaging. RESULTS: After PD-CSF treatment, microglia growth was reduced extensively, and a non-confluent pattern with morphological changes developed, that was not evident in disease control CSF and no-CSF treated cultures. Astrocyte growth rates were similarly reduced by exposure to PD-CSF, but morphological changes were not consistently noted. PD-CSF treated microglia showed a significant increase in α-synuclein content by day 4 compared to other treatments (p ≤ 0.02). In microglia only, α-synuclein aggregated and redistributed to peri-nuclear locations. CONCLUSIONS: Cultured microglia and astrocytes are differentially affected by PD-CSF exposure compared to non-PD-CSF controls. PD-CSF dramatically impacts microglia cell growth, morphology, and α-synuclein deposition compared to astrocytes, supporting the hypothesis of cell specific susceptibility to PD-CSF toxicity.
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OBJECTIVE Neuro-imaging studies have suggested that the ability to imitate meaningless and meaningful gestures may differentially depend on superior (SPL) and inferior (IPL) parietal lobule. Therefore, we hypothesized that imaging-guided neuro-navigated continuous theta burst stimulation (cTBS) over left SPL mainly affects meaningless and over left IPL predominantly meaningful gestures. METHODS Twelve healthy subjects participated in this study. High resolution structural MRI was used for imaging guided neuro-navigation cTBS. Participants were targeted with one train of cTBS in three experimental sessions: sham stimulation over vertex and real cTBS over left SPL and IPL, respectively. An imitation task, including 24 meaningless and 24 meaningful gestures, was performed 'offline'. RESULTS cTBS over both left IPL and SPL significantly interfered with gestural imitation. There was no differential effect of SPL and IPL cTBS on gesture type (meaningless versus meaningful). CONCLUSIONS Our findings confirm that left posterior parietal cortex plays a predominant role in gestural imitation. However, the hypothesis based on the dual route model suggesting a differential role of SPL and IPL in the processing of meaningless and meaningful gestures could not be confirmed. SIGNIFICANCE Left SPL and IPL play a common role within the posterior-parietal network in gestural imitation regardless of semantic content.
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The following commentary serves as a response to the article, “Family Stability and Childhood Behavioral Outcomes: A Critical Review of the Literature.” The review article provides a good overview into family factors affecting children, but falls short in discussing how modifying family factors could change specific child behavioral outcomes. The next step in this field of research is a unified definition of family stability, a standardized measure of family stability, and discussion of how child behavior affects family stability, and how changes in family stability could affect child behavior.
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Food insecurity (FI) affects millions of people in the United States and is associated with medical problems, as well as poorer physical and emotional-behavioral adjustment. Failure to thrive is a condition where children fail to gain an appropriate amount of weight, and it can cause long-term effects on cognitive and psychomotor development. While the extent to which FI may contribute to FTT is unclear, FI may contribute both directly through inadequate caloric or nutrient intake and indirectly through increased family stress, parental depression and a chaotic family environment. We present an overview of how FI and FTT may interact, followed by a case study from our multidisciplinary clinic for children with FTT. The importance of screening for FI as well as FTT is discussed. We describe ways for individuals, organizations, and agencies to help reduce the effects of FI in both individuals and their communities.
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Vitamin B$\sb6$ (or pyridoxal 5$\sp\prime$-phosphate, PLP) is an essential, ubiquitous coenzyme that affects many aspects of amino acid and cellular metabolism in all organisms. The goal of this thesis is to examine the regulation of PLP biosynthesis in Escherichia coli K-12. First, PdxH oxidase is a PLP biosynthetic enzyme, which uses molecular oxygen as an electron acceptor under aerobic assay conditions. To test if facultative anaerobic E. coli uses another enzyme to replace the function of PdxH oxidase anaerobically, suppressors of a pdxH null mutant were isolated anaerobically after 2-aminopurine or spontaneous mutagenesis. Only one specific bypass mutation in another PLP biosynthetic gene pdxJ was found, suggesting that PdxH oxidase is able to function anaerobically and PdxT utilizes D-1-deoxyxyulose as a substrate. Second, regulation of the serC (pdxF)-aroA operon, which is involved the biosynthesis of L-serine, PLP and aromatic compounds was examined. A serC (pdxF) single gene transcript and a serC (pdXf)-aroA cotranscript initiated at P$\sb{serC\ (pdxF)}$ upstream of serC (pdxF) were detected. The expression of the operon is activated by leucine responsive regulatory protein (LRP) and repressed by cAMP receptor protein-cAMP complex (CRP$\cdot$cAMP) at the transcriptional level. LRP activates the operon by directly binding to the upstream consensus box. Binding of CRP$\cdot$cAMP to the upstream CRP box diminishes the activation effect of LRP. However, deletion of the CRP box did not affect the repression of CRP$\cdot$cAMP, suggesting that CRP$\cdot$cAMP may repress the operon indirectly by stimulating the activity or level of an unidentified repressor. The overall effect of this regulation is to maximize the expression of the operon when the cells are growing in minimal-glucose medium. In addition, the binding and the transcription of P$\sb{serC\ (pdxF)}$ by RNA polymerase require a supercoiled circular DNA, indicating that DNA supercoiling affects the transcription of the operon. Third, regulation of another PLP biosynthetic gene gapB was also examined. gapB is activated by CRP$\cdot$cAMP and repressed by catabolic repressor activator protein (CRA). However, the activation of CRP$\cdot$cAMP is epistatic to the repression of CRA. Due to the CRA repression, gapB was expressed at a low level in all the media tested, suggesting that it may be the rate-limiting step of PLP biosynthesis. In summary, unlike genes in many biosynthetic pathways, PLP biosynthetic genes are regulated by global regulators that are important for carbon and amino acid metabolism, instead of the end product(s) of the pathway. ^
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Feather pecking in laying hens is a serious behavioral problem that is often associated with feather eating. The intake of feathers may influence the gut microbiota and its metabolism. The aim of this study was to determine the effect of 2 different diets, with or without 5% ground feathers, on the gut microbiota and the resulting microbial fermentation products and to identify keratin-degrading bacteria in chicken digesta. One-day-old Lohmann-Selected Leghorn chicks were divided into 3 feeding groups: group A (control), B (5% ground feathers in the diet), and C, in which the control diet was fed until wk 12 and then switched to the 5% feather diet to study the effect of time of first feather ingestion. The gut microbiota was analyzed by cultivation and denaturing gradient gel electrophoresis of ileum and cecum digesta. Short-chain fatty acids, ammonia, and lactate concentrations were measured as microbial metabolites. The concentration of keratinolytic bacteria increased after feather ingestion in the ileum (P < 0.001) and cecum (P = 0.033). Bacterial species that hydrolyzed keratin were identified as Enterococcus faecium, Lactobacillus crispatus, Lactobacillus reuteri-like species (97% sequence homology), and Lactobacillus salivarius-like species (97% sequence homology). Molecular analysis of cecal DNA extracts showed that the feather diet lowered the bacterial diversity indicated by a reduced richness (P < 0.001) and shannon (P = 0.012) index. The pattern of microbial metabolites indicated some changes, especially in the cecum. This study showed that feather intake induced an adaptation of the intestinal microbiota in chickens. It remains unclear to what extent the changed metabolism of the microbiota reflects the feather intake and could have an effect on the behavior of the hens.
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This paper investigates empirically the Bolton, Scheinkman, and Xiong (2006) hypothesis, according to which initial shareholders may provide incentives to managers to take actions that stimulate speculative bubbles. We test this hypothesis with data on up to 8,544 directors and up to 1,677 companies between 2004-2008. Using vesting time as a measure of the short-term performance weighting in CEO compensation and various alternative measures of the extent of speculation, the findings support the hypothesis: vesting time decreases with more intensive speculation. The results prove robust in various empirical model specifications.
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PURPOSE To determine the impact of long-term storage on adhesion between titanium and zirconia using resin cements. MATERIALS AND METHODS Titanium grade 4 blocks were adhesively fixed onto zirconia disks with four resin cements: Panavia F 2.0 (Kuraray Europe), GC G-Cem (GC Europe), RelyX Unicem (3M ESPE), and SmartCem 2 (Dentsply DeguDent). Shear bond strength was determined after storage in a water bath for 24 h, 16, 90, and 150 days at 37°C, and after 6000 cycles between 5°C and 55°C. Fracture behavior was evaluated using scanning electron microscopy. RESULTS After storage for at least 90 days and after thermocycling, GC G-Cem (16.9 MPa and 15.1 MPa, respectively) and RelyX Unicem (10.8 MPa and 15.7 MPa, respectively) achieved higher shear bond strength compared to SmartCem 2 (7.1 MPa and 4.0 MPa, respectively) and Panavia F2 (4.1 MPa and 7.4 MPa, respectively). At day 150, GC G-Cem and RelyX Unicem caused exclusively mixed fractures. SmartCem 2 and Panavia F2 showed adhesive fractures in one-third of the cases; all other fractures were of mixed type. After 24 h (GC G-Cem: 26.0, RelyX Unicem: 20.5 MPa, SmartCem 2: 16.1 MPa, Panavia F2: 23.6 MPa) and 16 days (GC G-Cem: 12.8, RelyX Unicem: 14.2 MPa, SmartCem 2: 9.8 MPa, Panavia F2: 14.7 MPa) of storage, shear bond strength was similar among the four cements. CONCLUSION Long-term storage and thermocycling differentially affects the bonding of resin cement between titanium and zirconia.
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INTRODUCTION Supplementation with beta-alanine may have positive effects on severe-intensity, intermittent, and isometric strength-endurance performance. These could be advantageous for competitive alpine skiers, whose races last 45 to 150 s, require metabolic power above the aerobic maximum, and involve isometric muscle work. Further, beta-alanine supplementation affects the muscle force-frequency relationship, which could influence explosiveness. We explored the effects of beta-alanine on explosive jump performance, severe exercise energy metabolism, and severe-intensity ski-like performance. METHODS Nine male elite alpine skiers consumed 4.8 g/d beta-alanine or placebo for 5 weeks in a double-blind fashion. Before and after, they performed countermovement jumps (CMJ), a 90-s cycling bout at 110% VO2max (CLT), and a maximal 90-s box jump test (BJ90). RESULTS Beta-alanine improved maximal (+7 ± 3%, d = 0.9) and mean CMJ power (+7 ± 2%, d = 0.7), tended to reduce oxygen deficit (-3 ± 8%, p = .06) and lactate accumulation (-12 ± 31%) and enhance aerobic energy contribution (+1.3 ± 2.9%, p = .07) in the CLT, and improved performance in the last third of BJ90 (+7 ± 4%, p = .02). These effects were not observed with placebo. CONCLUSIONS Beta-alanine supplementation improved explosive and repeated jump performance in elite alpine skiers. Enhanced muscle contractility could possibly explain improved explosive and repeated jump performance. Increased aerobic energy production could possibly help explain repeated jump performance as well.
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Recent studies have shown that women are more sensitive than men to subtle cuteness differences in infant faces. It has been suggested that raised levels in estradiol and progesterone may be responsible for this advantage. We compared young women's sensitivity to computer-manipulated baby faces varying in cuteness. Thirty-six women were tested once during ovulation and once during the luteal phase of their menstrual cycle. In a two alternative forced-choice experiment, participants chose the baby which they thought was cuter (Task 1), younger (Task 2), or the baby that they would prefer to babysit (Task 3). Saliva samples to assess levels of estradiol, progesterone and testosterone were collected at each test session. During ovulation, women were more likely to choose the cuter baby than during the luteal phase, in all three tasks. These results suggest that cuteness discrimination may be driven by cyclic hormonal shifts. However none of the measured hormones were related to increased cuteness sensitivity. We speculate that other hormones than the ones measured here might be responsible for the increased sensitivity to subtle cuteness differences during ovulation.
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The present article analyzed, how need for cognition (NFC) influences the formation of performance expectancies. When processing information, individuals with lower NFC often rely on salient information and shortcuts compared to individuals higher in NFC. We assume that these preferences of processing will also make individuals low in NFC more responsive to salient achievement-related cues because the processing of salient cues is cognitively less demanding than the processing of non-salient cues. Therefore, individuals lower in NFC should tend to draw wider ranging inferences from salient achievement-related information. In a sample of N = 197 secondary school students, achievement-related feedback (grade on an English examination) affected changes in expectancies in non-corresponding academic subjects (e.g., expectation of final grade in mathematics or history) when NFC was lower, whereas for students with higher NFC, changes in expectancies in non-corresponding academic subjects were not affected.