Surface modification of hydrophobic polymers for improvement of endothelial cell-surface interactions

The aim of this study is to improve the interaction of endothelial cells with polymers used in vascular prostheses. Polytetrafluoroethylene (PTFE; Teflon) films were treated by means of nitrogen and oxygen plasmas. Depending on the plasma exposure time, modified PTFE surfaces showed water-contact angles of 15¿58° versus 96° for unmodified PTFE. Electron spectroscopy in chemical analysis (ESCA) measurements revealed incorporation of both nitrogenand oxygen-containing groups into the PTFE surfaces, dependent on the plasma composition and exposure time. In-vitro biological evaluation of unmodified and modified PTFE surfaces showed that human endothelial cells, seeded from 20% human serum-containing culture medium, adhered well on to modified PTFE surfaces, but not on to unmodified films. Adhesion of endothelial cells on to expanded PTFE graft material (Gore-Tex) was also stimulated by plasma treatment of this substrate. On plasma-treated expanded PTFE, the adhering endothelial cells formed a monolayer, which covered the textured surface. The latter observation is important in view of the hemocompatibility of vascular grafts seeded with endothelial cells before implantation

A Review of the Design Process for Implantable Orthopedic Medical Devices

The design process for medical devices is highly regulated to ensure the safety of patients. This paper will present a review of the design process for implantable orthopedic medical devices. It will cover the main stages of feasibility, design reviews, design, design verification, manufacture, design validation, design transfer and design changes

Herbal medicine: women's views, knowledge and interaction with doctors: a qualitative study

BACKGROUND: There is growing concern that serious interactions are occurring between prescribed/over the counter and herbal medicines and that there is a lack of disclosure of herbal use by patients to doctors. This study explores women's perspectives about the safety of herbal remedies, herb-drug interactions and communication with doctors about herbal medicines. METHODS: Qualitative, cross-sectional study, with purposive sampling which took place in Cheshire, UK. Eighteen in depth semi-structured interviews were conducted with female herbal medicine users aged 18 years and above. RESULTS: The large majority did not inform their GPs of their use of herbal medicines. This was due to lack of physician enquiry, perception of importance and fear of a negative response. Several women were not aware that herbal remedies could interact with prescribed or over the counter medicines. Of the women who had experienced adverse effects none had reported them, believing them of low importance. CONCLUSION: The women had little knowledge about herb-drug interactions and rarely disclosed use of herbal medicines to their doctor. Doctors' communication and openness regarding herbal medicines needs to improve and there should be increased access to accurate information on herbal medicines in the public and health care domain

Impairment of Auditory-Motor Timing and Compensatory Reorganization after Ventral Premotor Cortex Stimulation

Integrating auditory and motor information often requires precise timing as in speech and music. In humans, the position of the ventral premotor cortex (PMv) in the dorsal auditory stream renders this area a node for auditory-motor integration. Yet, it remains unknown whether the PMv is critical for auditory-motor timing and which activity increases help to preserve task performance following its disruption. 16 healthy volunteers participated in two sessions with fMRI measured at baseline and following rTMS (rTMS) of either the left PMv or a control region. Subjects synchronized left or right finger tapping to sub-second beat rates of auditory rhythms in the experimental task, and produced self-paced tapping during spectrally matched auditory stimuli in the control task. Left PMv rTMS impaired auditory-motor synchronization accuracy in the first sub-block following stimulation (p<0.01, Bonferroni corrected), but spared motor timing and attention to task. Task-related activity increased in the homologue right PMv, but did not predict the behavioral effect of rTMS. In contrast, anterior midline cerebellum revealed most pronounced activity increase in less impaired subjects. The present findings suggest a critical role of the left PMv in feed-forward computations enabling accurate auditory-motor timing, which can be compensated by activity modulations in the cerebellum, but not in the homologue region contralateral to stimulation

The Evolution of Compact Binary Star Systems

We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs) within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA). Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars -- compact binaries in which the Roche lobe is filled by another WD or a low-mass partially degenerate helium-star, as these stars are thought to be the best LISA verification binary GW sources.Comment: 105 pages, 18 figure

Measurement of soluble CD59 in CSF in demyelinating disease: Evidence for an intrathecal source of soluble CD59

Background: CD59, a broadly expressed glycosylphosphatidylinositol-anchored protein, is the principal cell inhibitor of complement membrane attack on cells. In the demyelinating disorders, multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD), elevated complement protein levels, including soluble CD59 (sCD59), were reported in cerebrospinal fluid (CSF). Objectives: We compared sCD59 levels in CSF and matched plasma in controls and patients with MS, NMOSD and clinically isolated syndrome (CIS) and investigated the source of CSF sCD59 and whether it was microparticle associated. Methods: sCD59 was quantified using enzyme-linked immunosorbent assay (ELISA; Hycult; HK374-02). Patient and control CSF was subjected to western blotting to characterise anti-CD59-reactive materials. CD59 was localised by immunostaining and in situ hybridisation. Results: CSF sCD59 levels were double those in plasma (CSF, 30.2 ng/mL; plasma, 16.3 ng/mL). Plasma but not CSF sCD59 levels differentiated MS from NMOSD, MS from CIS and NMOSD/CIS from controls. Elimination of microparticles confirmed that CSF sCD59 was not membrane anchored. Conclusion: CSF levels of sCD59 are not a biomarker of demyelinating diseases. High levels of sCD59 in CSF relative to plasma suggest an intrathecal source; CD59 expression in brain parenchyma was low, but expression was strong on choroid plexus (CP) epithelium, immediately adjacent the CSF, suggesting that this is the likely source

New Zealand Blackcurrant Extract Improves Cycling Performance and Fat Oxidation in Cyclists

PURPOSE: Blackcurrant intake increases peripheral blood flow in humans, potentially by anthocyanin-induced vasodilation which may affect substrate delivery and exercise performance. We examined the effects of New Zealand blackcurrant (NZBC) extract on substrate oxidation, cycling time-trial performance and plasma lactate responses following the time-trial in trained cyclists. METHODS: Using a randomized, double-blind, crossover design, fourteen healthy men (age: 38 ± 13 years, height: 178 ± 4 cm, body mass: 77 ± 9 kg, V?O2max: 53 ± 6 ml·kg-1·min-1, mean ± SD) ingested NZBC extract (300 mg?day-1 CurraNZ™ containing 105 mg anthocyanin) or placebo (PL, 300 mg microcrystalline cellulose M102) for 7-days (washout 14-days). On day 7, participants performed 30 min of cycling (3x10 min at 45, 55 and 65% V?O2max), followed by a 16.1 km time-trial with lactate sampling during a 20-minute passive recovery. RESULTS: NZBC extract increased fat oxidation at 65% V?O2max by 27% (P < 0.05) and improved 16.1 km time-trial performance by 2.4% (NZBC: 1678 ± 108 s, PL: 1722 ± 131 s, P < 0.05). Plasma lactate was higher with NZBC extract immediately following the time-trial (NZBC: 7.06 ± 1.73 mmol?L-1, PL: 5.92 ± 1.58 mmol?L-1 P < 0.01). CONCLUSIONS: Seven days intake of New Zealand blackcurrant extract improves 16.1 km cycling time-trial performance and increases fat oxidation during moderate intensity cycling

Antimalarial Therapy Selection for Quinolone Resistance among Escherichia coli in the Absence of Quinolone Exposure, in Tropical South America

BACKGROUND: Bacterial resistance to antibiotics is thought to develop only in the presence of antibiotic pressure. Here we show evidence to suggest that fluoroquinolone resistance in Escherichia coli has developed in the absence of fluoroquinolone use. METHODS: Over 4 years, outreach clinic attendees in one moderately remote and five very remote villages in rural Guyana were surveyed for the presence of rectal carriage of ciprofloxacin-resistant gram-negative bacilli (GNB). Drinking water was tested for the presence of resistant GNB by culture, and the presence of antibacterial agents and chloroquine by HPLC. The development of ciprofloxacin resistance in E. coli was examined after serial exposure to chloroquine. Patient and laboratory isolates of E. coli resistant to ciprofloxacin were assessed by PCR-sequencing for quinolone-resistance-determining-region (QRDR) mutations. RESULTS: In the very remote villages, 4.8% of patients carried ciprofloxacin-resistant E. coli with QRDR mutations despite no local availability of quinolones. However, there had been extensive local use of chloroquine, with higher prevalence of resistance seen in the villages shortly after a Plasmodium vivax epidemic (p<0.01). Antibacterial agents were not found in the drinking water, but chloroquine was demonstrated to be present. Chloroquine was found to inhibit the growth of E. coli in vitro. Replica plating demonstrated that 2-step QRDR mutations could be induced in E. coli in response to chloroquine. CONCLUSIONS: In these remote communities, the heavy use of chloroquine to treat malaria likely selected for ciprofloxacin resistance in E. coli. This may be an important public health problem in malarious areas