A role for calcitonin gene-related peptide in rabbit knee joint ligament healing

Knee joint ligament healing has been shown to be improved when the torn ligament ends remain in contact, however, the rationale for these effects is unknown. The sensory neuropeptide calcitonin gene related peptide (CGRP) has potent trophic and vasodilatatory properties and as such is thought to be advantageous in wound repair. In ascertaining a role for CGRP in rabbit medial collateral ligament healing, the present study examined changes in CGRP-like immunoreactivity (CGRP-LI) and CGRP-mediated vasomotor responses in gap injured (non-contact), Z-plasty apposed (contact), and sham operated control medial collateral ligaments. At 6 weeks post-trauma, CGRP-LI decreased in the healing zone of gap injured and Z-plasty apposed medial collateral ligaments compared with controls, and non-contact ligament nerve fibres exhibited an abnormal morphology. Topical administration of CGRP (10(-13) to 10(-9) mol) caused a dose-dependent increase in ligament perfusion in each experimental group of knees. The CGRP-mediated vasodilatation associated with gap injured ligaments was not significantly different from controls (P = 0.06), whereas apposed medial collateral ligaments showed an augmented response to the peptide (P < 0.0005). These findings indicate that the beneficial effects of ligament interposition post-trauma may be related to an enhanced responsiveness to CGRP in conjunction with a more typical re-innervation profile. Conversely, the aberrant characteristics of CGRP-LI nerves occurring in gap injured tissue is suggestive of impaired CGRP release which may explain the poor functional recovery associated with these ligaments.     

Sperm-induced calcium oscillations at fertilisation in ascidians are controlled by cyclin B1-dependent kinase activity

The generation of calcium oscillations at fertilisation and during mitosis appears to be controlled by the cell cycle machinery. For example, the calcium oscillations in oocytes and embryos occur during metaphase and terminate upon entry into interphase. Here we report the manipulation of sperm-triggered calcium oscillations by cyclin-dependent kinase (CDK) activity, the major component of maturation/M phase promoting factor (MPF). To control the CDK activity we microinjected mRNAs encoding full-length GFP-tagged cyclin B1 or a truncated and therefore stabilised form of cyclin B1 ((delta)90) into unfertilised oocytes. In the presence of full-length cyclin B1, the calcium oscillations terminate when cyclin B1 levels fall along with the concomitant fall in the associated CDK activity. In addition, when the CDK activity is elevated indefinitely with (delta)90 cyclin B1, the calcium oscillations also continue indefinitely. Finally, in oocytes that contain low mitogen-activated protein (MAP) kinase activity and elevated CDK activity, the sperm-triggered calcium oscillations are again prolonged. We conclude that the CDK activity of the ascidian oocyte can be regarded as a positive regulator of sperm-triggered calcium oscillations, a finding that may apply to other oocytes that display sperm-triggered calcium oscillations at fertilisation. Furthermore, these findings may have a bearing upon the mitotic calcium signals of early embryos.     

Parental virtue: a new way of thinking about the morality of reproductive actions

In this paper I explore the potential of virtue ethical ideas to generate a new way of thinking about the ethical questions surrounding the creation of children. Applying ideas from neo‐Aristotelian virtue ethics to the parental sphere specifically, I develop a framework for the moral assessment of reproductive actions that centres on the concept of parental virtue. I suggest that the character traits of the good parent can be used as a basis for determining the moral permissibility of a particular reproductive action. I posit three parental virtues and argue that we can see the moral status of a reproductive action as determined by the relationship between such an action and (at least) these virtues. Using a case involving selection for deafness, I argue that thinking in terms of the question ‘would a virtuous parent do this?’ when morally assessing reproductive action is a viable and useful way of thinking about issues in reproductive ethics.     

Neuropeptides regulate expression of matrix molecule, growth factor and inflammatory mediator mRNA in explants of normal and healing medial collateral ligament

Denervation degrades normal ligament properties and impairs ligament healing. This suggests that secreted neuromediators, such as neuropeptides, could be modulating cell metabolism in ligament and scar tissue. To test this hypothesis we investigated the effect of exogenous substance P (SP), neuropeptide Y (NPY) or calcitonin gene-related peptide (CGRP) on the mRNA levels for proteins associated with inflammation, angiogenesis, and matrix production in tissue-cultured specimens of normal and injured medial collateral ligament. SP and NPY induced increased mRNA levels for several inflammatory mediators in the 2-week post-injury specimens. All three neuropeptides induced decreases in mRNA levels for healing-associated growth factors and matrix molecules, including basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF) and collagen types I and III. The results indicate that neuropeptides strongly influence the metabolic activity of cells in healing ligament, particularly at early time points after injury.     

Antiproliferative activity is predominantly associated with ellagitannins in raspberry extracts

Raspberry extracts enriched in polyphenols, but devoid of organic acids, sugars and vitamin C, were prepared by sorption to C18 solid phase extraction matrices and tested for their ability to inhibit the proliferation of human cervical cancer (HeLa) cells in vitro. The raspberry extract reduced proliferation in a dose-dependent manner whether this was judged by cell number or measurements of cell viability. However, measurements based on cell viability were more accurate and gave an EC(50) value of 17.5 microg/ml gallic acid equivalents (GAE) at day 4 of culture. Raspberry extracts were fractionated by sorption to Sephadex LH-20 into an unbound fraction, which was obviously enriched in anthocyanins, and a bound fraction. The unbound anthocyanin-enriched fraction was much less effective in reducing proliferation then the original extract and gave an EC(50) value estimated at 67 microg/ml. The LH-20 bound fraction was more effective than the original raspberry extract (EC(50)=13 microg/ml) suggesting that the main anti-proliferative agents were retained in the bound fraction. Analysis of the original extract, the unbound and the LH20 bound fractions by LC-MS confirmed that the unbound fraction was enriched in anthocyanins and the bound fraction primarily contained ellagitannins. The ellagitannin-rich bound fraction had the highest antioxidant capacity as measured by the ferric reducing antioxidant potential (FRAP) assay. The mechanism by which the ellagitannins inhibit proliferation of cancer cells is discussed.     

Annual compositional variation in wild Osmundea pinnatifida (Hudson) Stackhouse from the west coast of Scotland

Journal of Applied Phycology - Osmundea pinnatifida (Pepper Dulse) is a commercially interesting red alga harvested from the wild and sold dried as seasoning due to its distinctive peppery taste....     

A luminescent assay for real-time measurements of receptor endocytosis in living cells

Ligand-mediated endocytosis is a key autoregulatory mechanism governing the duration and intensity of signals emanating from cell surface receptors. Due to the mechanistic complexity of endocytosis and its emerging relevance in disease, simple methods capable of tracking this dynamic process in cells have become increasingly desirable. We have developed a bioluminescent reporter technology for real-time analysis of ligand-mediated receptor endocytosis using genetic fusions of NanoLuc luciferase with various G-protein-coupled receptors (GPCRs). This method is compatible with standard microplate formats, which should decrease work flows for high-throughput screens. This article also describes the application of this technology to endocytosis of epidermal growth factor receptor (EGFR), demonstrating potential applicability of the method beyond GPCRs.     

The effect of estrogen on muscle damage biomarkers following prolonged aerobic exercise in eumenorrheic women

This study assessed the influence of estrogen (E₂) on muscle damage biomarkers [skeletal muscle - creatine kinase (CK); cardiac muscle - CK-MB] responses to prolonged aerobic exercise. Eumenorrheic women (n=10) who were physically active completed two 60-minute treadmill running sessions at ∼60-65% maximal intensity during low E₂ (midfollicular menstrual phase) and high E₂ (midluteal menstrual phase) hormonal conditions. Blood samples were collected prior to exercise (following supine rest), immediately post-, 30 min post-, and 24 hours post-exercise to determine changes in muscle biomarkers. Resting blood samples confirmed appropriate E₂ hormonal levels Total CK concentrations increased following exercise and at 24 hours post-exercise were higher in the midfollicular low E₂ phase (p<0.001). However, CK-MB concentrations were unaffected by E₂ level or exercise (p=0.442) resulting in the ratio of CK-MB to total CK being consistently low in subject responses (i.e., indicative of skeletal muscle damage). Elevated E₂ levels reduce the CK responses of skeletal muscle, but had no effect on CK-MB responses following prolonged aerobic exercise. These findings support earlier work showing elevated E₂ is protective of skeletal muscle from exercise-induced damage associated with prolonged aerobic exercise.     

Short-term behavioral consequences of territory relocation in a Caribbean damselfish, Stegastes diencaeus

Home-range relocation occurs during natal and breeding dispersal,ontogenetic habitat shifts, and the maintenance of resource-or density-dependent patterns of distribution. Relocating animalsare expected to change their behavior to compensate for limitedfamiliarity with the new home range and with neighboring conspecifics;such changes may indicate some of the costs of relocation. Littleis known, however, about the magnitude and duration of the changesor about the types of behavior affected. We investigated theshort-term (2 day) behavioral changes associated with relocationin the highly territorial longfin damselfish, Stegastes diencaeus.We compared the behavior of newcomers settling into experimentallycreated vacancies in an established neighborhood with that ofthe original residents of the same territories. The greatestdifference was an increase in the rate of agonistic interactions.Newcomers also used smaller territories, moved more, and fedless. Neighboring damselfishes were less aggressive toward neighborsthat expanded into vacant territories than toward "strangers"that relocated from elsewhere. The behavior of newcomers approachedthat of original residents within 2 days but territory sizedid not. These observations suggest that relocating a territoryincreases energy expenditure and decreases energy intake. Suchcosts could explain the philopatry of reef fish when alternativelocations are of uncertain quality or are only slightly better.Nevertheless, they are unlikely to outweigh the long-term benefitsof obtaining a superior territory—especially for individualsfrom adjacent territories.     

ERK- and JNK-signalling regulate gene networks that stimulate metamorphosis and apoptosis in tail tissues of ascidian tadpoles

In ascidian tadpoles, metamorphosis is triggered by a polarized wave of apoptosis, via mechanisms that are largely unknown. We demonstrate that the MAP kinases ERK and JNK are both required for the wave of apoptosis and metamorphosis. By employing a gene-profiling-based approach, we identified the network of genes controlled by either ERK or JNK activity that stimulate the onset of apoptosis. This approach identified a gene network involved in hormonal signalling, in innate immunity, in cell-cell communication and in the extracellular matrix. Through gene silencing, we show that Ci-sushi, a cell-cell communication protein controlled by JNK activity, is required for the wave of apoptosis that precedes tail regression. These observations lead us to propose a model of metamorphosis whereby JNK activity in the CNS induces apoptosis in several adjacent tissues that compose the tail by inducing the expression of genes such as Ci-sushi.