68 research outputs found

    High-throughput characterisation of bull semen motility using differential dynamic microscopy

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    <div><p>We report a high-throughput technique for characterising the motility of spermatozoa using differential dynamic microscopy. A movie with large field of view (∼10mm<sup>2</sup>) records thousands of cells (e.g. ≈ 5000 cells even at a low cell density of 20 × 10<sup>6</sup> cells/ml) at once and yields averaged measurements of the mean () and standard deviation (<i>σ</i>) of the swimming speed, head oscillation amplitude (<i>A</i><sub>0</sub>) and frequency (<i>f</i><sub>0</sub>), and the fraction of motile spermatozoa (<i>α</i>). Interestingly, we found that the measurement of <i>α</i> is facilitated because the swimming spermatozoa enhance the motion of the non-swimming population. We demonstrate the ease and rapidity of our method by performing on-farm characterisation of bull spermatozoa motility, and validate the technique by comparing laboratory measurements with tracking. Our results confirm the long-standing theoretical prediction that for swimming spermatozoa.</p></div

    Dose-dependent effects of Allopurinol on human foreskin fibroblast cell and human umbilical vein endothelial cell under hypoxia

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    Allopurinol, an inhibitor of xanthine oxidase, has been used in clinical trials of patients with cardiovascular and chronic kidney disease. These are two pathologies with extensive links to hypoxia and activation of the transcription factor hypoxia inducible factor (HIF) family. Here we analysed the effects of allopurinol treatment in two different cellular models, and their response to hypoxia. We explored the dose-dependent effect of allopurinol on Human Foreskin Fibroblasts (HFF) and Human Umbilical Vein Endothelial Cells (HUVEC) under hypoxia and normoxia. Under normoxia and hypoxia, high dose allopurinol reduced the accumulation of HIF-1α protein in HFF and HUVEC cells. Allopurinol had only marginal effects on HIF-1α mRNA level in both cellular systems. Interestingly, allopurinol effects over the HIF system were independent of prolyl-hydroxylase activity. Finally, allopurinol treatment reduced angiogenesis traits in HUVEC cells in an in vitro model. Taken together these results indicate that high doses of allopurinol inhibits the HIF system and pro-angiogenic traits in cells

    Water interaction differences determine the relative energetic stability of the polyproline II conformation of the alanine dipeptide in aqueous environments

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    Although subsequent studies have provided extensive support for the 1968 Tiffany and Krimm proposal (Biopolymers 6, 1379) that the polyproline II (PPII) conformation is a significant component of the structure of unordered polypeptide chains, two issues are still not fully resolved: the PPII persistence length in a chain and the source of its relative stability with respect to the β‐conformation. We examine the latter question by studying the B97‐D/6‐31++G ** energy, in the absence and presence of a reaction field, of the alanine dipeptide hydrated by various amounts of explicit waters and resolving this into its three components: the energies of the individual solvated peptides and water structures plus the interaction energy involving them. We find that the relative stability of the PPII conformation is determined mainly by the difference in the interaction energies of the water structures in the near‐peptide layers. © 2012 Wiley Periodicals, Inc. Biopolymers 97: 789–794, 2012.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92429/1/22064_ftp.pd

    The Gut Microbiome Contributes to a Substantial Proportion of the Variation in Blood Lipids

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    Rationale: Evidence suggests that the gut microbiome is involved in the development of cardiovascular disease, with the host–microbe interaction regulating immune and metabolic pathways. However, there was no firm evidence for associations between microbiota and metabolic risk factors for cardiovascular disease from large-scale studies in humans. In particular, there was no strong evidence for association between cardiovascular disease and aberrant blood lipid levels. Objectives: To identify intestinal bacteria taxa, whose proportions correlate with body mass index and lipid levels, and to determine whether lipid variance can be explained by microbiota relative to age, sex, and host genetics. Methods and Results: We studied 893 subjects from the LifeLines-DEEP population cohort. After correcting for age and sex, we identified 34 bacterial taxa associated with body mass index and blood lipids; most are novel associations. Cross-validation analysis revealed that microbiota explain 4.5% of the variance in body mass index, 6% in triglycerides, and 4% in high-density lipoproteins, independent of age, sex, and genetic risk factors. A novel risk model, including the gut microbiome explained ≤25.9% of high-density lipoprotein variance, significantly outperforming the risk model without microbiome. Strikingly, the microbiome had little effect on low-density lipoproteins or total cholesterol. Conclusions: Our studies suggest that the gut microbiome may play an important role in the variation in body mass index and blood lipid levels, independent of age, sex, and host genetics. Our findings support the potential of therapies altering the gut microbiome to control body mass, triglycerides, and high-density lipoproteins

    Doublecortin maintains bipolar shape and nuclear translocation during migration in the adult forebrain

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    The ability of the mature mammalian nervous system to continually produce neuronal precursors is of considerable importance, as manipulation of this process might one day permit the replacement of cells lost as a result of injury or disease. In mammals, the anterior subventricular zone (SVZa) region is one of the primary sites of adult neurogenesis. Here we show that doublecortin (DCX), a widely used marker for newly generated neurons, when deleted in mice results in a severe morphological defect in the rostral migratory stream and delayed neuronal migration that is independent of direction or responsiveness to Slit chemorepulsion. DCX is required for nuclear translocation and maintenance of bipolar morphology during migration of these cells. Our data identifies a critical function for DCX in the movement of newly generated neurons in the adult brain

    Hormone Delivery System: The Contraceptive Ring

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    Many women use contraceptive methods that involve the hormones estrogen and progestin, which prevent the ovaries from developing and releasing mature eggs. This, therefore, prevents conception. Currently there are two well established types of birth control on the market. These possibilities are the pill form where the user ingests a large dose once a day for 21 days or the birth control patch is placed on the skin every week for three weeks out of the month. Women can also receive hormone shots or implants that last for four months. However, these methods only allow a menstrual cycle every four months, so they are difficult to compare to the other methods. All of these other methods can cause side effects such as headaches, blood clots, nausea, and breakthrough bleeding. However, there is a new form of birth control that comes in a flexible thin ring that is inserted into the vagina below the cervix. This ring is designed to releases a continuous low dose of hormone that is absorbed by the vagina and distributed into the blood stream. The ring actually releases two derivatives of estrogen and progestin known as etonogestrel and ethinyl estradiol (Organon USA Inc. 2005). See Figure 1 for the chemical structures of both of these compounds. Because the ring is only changed once a month, it ceases the fluctuation of hormone levels that is normal in the other birth control methods
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