632 research outputs found
Pilot Study: Placental Weight Ratio in Diabetic Women with Preeclampsia
Birth weight, a simple measure of birth outcome, has a key role in assessing infant health. A primary determinant of birth weight is a well grown, efficient placenta. Placental weight ratio (PWR) reflects the growth of the baby and placenta and is calculated by dividing the placental weight by fetal weight and is a proven useful health indicator. Preeclampsia (PE) is defined as new-onset hypertension and proteinuria during pregnancy and it is a major cause of maternal and fetal death worldwide. PE is associated with large placentae and small-for-gestational-age (SGA) infants; the PWR is expected to be increased in this condition. Another condition known to increase risk in pregnancy is type 2 diabetes mellitus (T2DM). T2DM is associated with large placentae and large-for-gestational-age (LGA) infants; the PWR is expected to be decreased. There is a paucity of information regarding the placental weight ratio when both PE and T2DM are present, particularly in American Indians (AI) and Hispanics, two groups known to be at increased risk for T2DM.
We hypothesize that AI and Hispanic mothers with PE and dysglycemia (T2DM, gestational diabetes), will have larger placentae and infants and PWR will be decreased.
We report data from samples collected in an ongoing study of the effects of dysglycemia on PE. Our findings demonstrate no significant differences in PWR between dysglycemic pregnancies and dysglycemic pregnancies with accompanying PE (p=0.29). This observation suggests that using the PWR to assess infant health outcome provides no additional benefit when applied to dysglycemic pregnancies with PE
Cross-tolerance to biotic and abiotic stresses in plants: a focus on resistance to aphid infestation
Plants co-evolved with an enormous variety of microbial pathogens and insect herbivores under daily and seasonal variations in abiotic environmental conditions. Hence, plant cells display a high capacity to respond to diverse stresses through a flexible and finely balanced response network that involves components such as reduction-oxidation (redox) signalling pathways, stress hormones and growth regulators, as well as calcium and protein kinase cascades. Biotic and abiotic stress responses use common signals, pathways and triggers leading to cross tolerance phenomena, whereby exposure to one type of stress can activate plant responses that facilitate tolerance to several different types of stress. While the acclimation mechanisms and adaptive responses that facilitate responses to single biotic and abiotic stresses have been extensively characterised, relatively little information is available on the dynamic aspects of combined biotic/abiotic stress response. In this review, we consider how the abiotic environment influences plant responses to attack by phloem-feeding aphids. Unravelling the signalling cascades that underpin cross tolerance to biotic and abiotic stresses will allow the identification of new targets for increasing environmental resilience in crops
Ascorbate Biosynthesis during Early Fruit Development Is the Main Reason for Its Accumulation in Kiwi
Background: Ascorbic acid (AsA) is a unique antioxidant as well as an enzyme cofactor. Although it has multiple roles in plants, it is unclear how its accumulation is controlled at the expression level, especially in sink tissues. Kiwifruit (Actinidia) is well-known for its high ascorbate content. Our objective was to determine whether AsA accumulates in the fruits primarily through biosynthesis or because it is imported from the foliage. Methodology/Principal Findings: We systematically investigated AsA levels, biosynthetic capacity, and mRNA expression of genes involved in AsA biosynthesis in kiwi (A. deliciosa cv. Qinmei). Recycling and AsA localization were also monitored during fruit development and among different tissue types. Over time, the amount of AsA, with its capacity for higher biosynthesis and lower recycling, peaked at 30 days after anthesis (DAA), and then decreased markedly up to 60 DAA before declining more slowly. Expression of key genes showed similar patterns of change, except for L-galactono-1,4-lactone dehydrogenase and L-galactose-1-phosphate phosphatase (GPP). However, GPP had good correlation with the rate of AsA accumulation. The expression of these genes could be detected in phloem of stem as well as petiole of leaf and fruit. Additionally, fruit petioles had greater ascorbate amounts, although that was the site of lowest expression by most genes. Fruit microtubule tissues also had higher AsA. However, exogenous applications of AsA to those petioles did not lead to its transport into fruits, and distribution of ascorbate was cell-specific in the fruits, with more accumulation occurring in large
A compendium and functional characterization of mammalian genes involved in adaptation to Arctic or Antarctic environments
Many mammals are well adapted to surviving in extremely cold environments. These species have likely accumulated genetic changes that help them efficiently cope with low temperatures. It is not known whether the same genes related to cold adaptation in one species would be under selection in another species. The aims of this study therefore were: to create a compendium of mammalian genes related to adaptations to a low temperature environment; to identify genes related to cold tolerance that have been subjected to independent positive selection in several species; to determine promising candidate genes/pathways/organs for further empirical research on cold adaptation in mammals
Biosynthesis of Vitamin C by Yeast Leads to Increased Stress Resistance
during respiration, or indirectly-caused by other stressing factors. Vitamin C or L-ascorbic acid acts as a scavenger of ROS, thereby potentially protecting cells from harmful oxidative products. While most eukaryotes synthesize ascorbic acid, yeast cells produce erythro-ascorbic acid instead. The actual importance of this antioxidant substance for the yeast is still a subject of scientific debate. is increased, but also the tolerance to low pH and weak organic acids at low pH is increased. cells endogenously producing vitamin C as a cellular model to study the genesis/protection of ROS as well as genotoxicity
Redox control of aphid resistance through altered cell wall composition and nutritional quality.
The mechanisms underpinning plant perception of phloem-feeding insects, particularly aphids, remain poorly characterized. Therefore, the role of apoplastic redox state in controlling aphid infestation was explored using transgenic tobacco (Nicotiana tabacum) plants that have either high (PAO) or low (TAO) ascorbate oxidase (AO) activities relative to the wild type. Only a small number of leaf transcripts and metabolites were changed in response to genotype, and cell wall composition was largely unaffected. Aphid fecundity was decreased significantly in TAO plants compared with other lines. Leaf sugar levels were increased and maximum extractable AO activities were decreased in response to aphids in all genotypes. Transcripts encoding the Respiratory Burst Oxidase Homolog F, signaling components involved in ethylene and other hormonemediated pathways, photosynthetic electron transport components, sugar, amino acid, and cell wall metabolism, were increased significantly in the TAO plants in response to aphid perception relative to other lines. The levels of galactosylated xyloglucan were decreased significantly in response to aphid feeding in all the lines, the effect being the least in the TAO plants. Similarly, all lines exhibited increases in tightly bound (1→4)-b-galactan. Taken together, these findings identify AO-dependent mechanisms that limit aphid infestation
Non-small cell lung carcinoma in an adolescent manifested by acute paraplegia due to spinal metastases: a case report
<p>Abstract</p> <p>Introduction</p> <p>Bronchial carcinomas in childhood and adolescence are extremely rare; only individual cases have been reported previously.</p> <p>Case presentation</p> <p>We report on a 16-year-old Caucasian German boy with non-small cell lung carcinoma (squamous cell non-small cell lung carcinoma) stage IV, T4N2M1, without epidermal growth factor receptor overexpression and/or mutation or k-ras mutation. He presented with paraplegia due to spinal metastases of the bronchial carcinoma. No familial predisposition or toxin exposure was identified. Treatment following adult protocols consisted of surgical intervention for spinal metastases, first-line cisplatinum and gemcitabine, irradiation and second-line docetaxel. After a transient response our patient experienced disease progression and died about 10 months later.</p> <p>Conclusion</p> <p>Response and survival in our 16-year-old patient were similar to adult patients with stage IV non-small cell lung carcinoma.</p
Building social capital through breastfeeding peer support: Insights from an evaluation of a voluntary breastfeeding peer support service in North-West England
Background:
Peer support is reported to be a key method to help build social capital in communities. To date there are no studies that describe how this can be achieved through a breastfeeding peer support service. In this paper we present findings from an evaluation of a voluntary model of breastfeeding peer support in North-West England to describe how the service was operationalized and embedded into the community. This study was undertaken from May, 2012 to May, 2013.
Methods:
Interviews (group or individual) were held with 87 participants: 24 breastfeeding women, 13 peer supporters and 50 health and community professionals. The data contained within 23 monthly monitoring reports (January, 2011 to February 2013) compiled by the voluntary peer support service were also extracted and analysed.
Results:
Thematic analysis was undertaken using social capital concepts as a theoretical lens. Key findings were identified to resonate with ’bonding’, ‘bridging’ and ‘linking’ forms of social capital. These insights illuminate how the peer support service facilitates ‘bonds’ with its members, and within and between women who access the service; how the service ‘bridges’ with individuals from different interests and backgrounds, and how ‘links’ were forged with those in authority to gain access and reach to women and to promote a breastfeeding culture. Some of the tensions highlighted within the social capital literature were also identified.
Conclusions:
Horizontal and vertical relationships forged between the peer support service and community members enabled peer support to be embedded into care pathways, helped to promote positive attitudes to breastfeeding and to disseminate knowledge and maximise reach for breastfeeding support across the community. Further effort to engage with those of different ethnic backgrounds and to resolve tensions between peer supporters and health professionals is warranted
Uptake and 4-week quit rates from an opt-out co-located smoking cessation service delivered alongside community-based low-dose computed tomography screening within the Yorkshire Lung Screening Trial.
BACKGROUND: Up to 50% of those attending for low-dose computed tomography screening for lung cancer continue to smoke and co-delivery of smoking cessation services alongside screening may maximise clinical benefit. Here we present data from an opt-out co-located smoking cessation service delivered alongside the Yorkshire Lung Screening Trial (YLST). METHODS: Eligible YLST participants were offered an immediate consultation with a smoking cessation practitioner (SCP) at their screening visit with ongoing smoking cessation support over subsequent weeks. RESULTS: Of 2150 eligible participants, 1905 (89%) accepted the offer of an SCP consultation during their initial visit, with 1609 (75%) receiving ongoing smoking cessation support over subsequent weeks. Uptake of ongoing support was not associated with age, ethnicity, deprivation or educational level in multivariable analyses, although men were less likely to engage (adjusted OR (ORadj) 0.71, 95% CI 0.56-0.89). Uptake was higher in those with higher nicotine dependency, motivation to stop smoking and self-efficacy for quitting. Overall, 323 participants self-reported quitting at 4 weeks (15.0% of the eligible population); 266 were validated by exhaled carbon monoxide (12.4%). Multivariable analyses of eligible smokers suggested 4-week quitting was more likely in men (ORadj 1.43, 95% CI 1.11-1.84), those with higher motivation to quit and previous quit attempts, while those with a stronger smoking habit in terms of cigarettes per day were less likely to quit. CONCLUSIONS: There was high uptake for co-located opt-out smoking cessation support across a wide range of participant demographics. Protected funding for integrated smoking cessation services should be considered to maximise programme equity and benefit
Monte Carlo Analysis of Neck Linker Extension in Kinesin Molecular Motors
Kinesin stepping is thought to involve both concerted conformational changes and diffusive movement, but the relative roles played by these two processes are not clear. The neck linker docking model is widely accepted in the field, but the remainder of the step – diffusion of the tethered head to the next binding site – is often assumed to occur rapidly with little mechanical resistance. Here, we investigate the effect of tethering by the neck linker on the diffusive movement of the kinesin head, and focus on the predicted behavior of motors with naturally or artificially extended neck linker domains. The kinesin chemomechanical cycle was modeled using a discrete-state Markov chain to describe chemical transitions. Brownian dynamics were used to model the tethered diffusion of the free head, incorporating resistive forces from the neck linker and a position-dependent microtubule binding rate. The Brownian dynamics and chemomechanical cycle were coupled to model processive runs consisting of many 8 nm steps. Three mechanical models of the neck linker were investigated: Constant Stiffness (a simple spring), Increasing Stiffness (analogous to a Worm-Like Chain), and Reflecting (negligible stiffness up to a limiting contour length). Motor velocities and run lengths from simulated paths were compared to experimental results from Kinesin-1 and a mutant containing an extended neck linker domain. When tethered by an increasingly stiff spring, the head is predicted to spend an unrealistically short amount of time within the binding zone, and extending the neck is predicted to increase both the velocity and processivity, contrary to experiments. These results suggest that the Worm-Like Chain is not an adequate model for the flexible neck linker domain. The model can be reconciled with experimental data if the neck linker is either much more compliant or much stiffer than generally assumed, or if weak kinesin-microtubule interactions stabilize the diffusing head near its binding site
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