Light scattering and phase behavior of Lysozyme-PEG mixtures

Measurements of liquid-liquid phase transition temperatures (cloud points) of mixtures of a protein (lysozyme) and a polymer, poly(ethylene glycol) (PEG) show that the addition of low molecular weight PEG stabilizes the mixture whereas high molecular weight PEG was destabilizing. We demonstrate that this behavior is inconsistent with an entropic depletion interaction between lysozyme and PEG and suggest that an energetic attraction between lysozyme and PEG is responsible. In order to independently characterize the lysozyme/PEG interactions, light scattering experiments on the same mixtures were performed to measure second and third virial coefficients. These measurements indicate that PEG induces repulsion between lysozyme molecules, contrary to the depletion prediction. Furthermore, it is shown that third virial terms must be included in the mixture's free energy in order to qualitatively capture our cloud point and light scattering data. The light scattering results were consistent with the cloud point measurements and indicate that attractions do exist between lysozyme and PEG.Comment: 5 pages, 2 figures, 1 tabl

Persistent frequent attenders in primary care: costs, reasons for attendance, organisation of care and potential for cognitive behavioural therapeutic intervention

<p><b>Abstract</b></p> <p>Background</p> <p>The top 3% of frequent attendance in primary care is associated with 15% of all appointments in primary care, a fivefold increase in hospital expenditure, and more mental disorder and functional somatic symptoms compared to normal attendance. Although often temporary if these rates of attendance last more than two years, they may become persistent (persistent frequent or regular attendance). However, there is no long-term study of the economic impact or clinical characteristics of regular attendance in primary care. Cognitive behaviour formulation and treatment (CBT) for regular attendance as a motivated behaviour may offer an understanding of the development, maintenance and treatment of regular attendance in the context of their health problems, cognitive processes and social context.</p> <p>Methods/design</p> <p>A case control design will compare the clinical characteristics, patterns of health care use and economic costs over the last 10 years of 100 regular attenders (≥30 appointments with general practitioner [GP] over 2 years) with 100 normal attenders (6–22 appointments with GP over 2 years), from purposefully selected primary care practices with differing organisation of care and patient demographics. Qualitative interviews with regular attending patients and practice staff will explore patient barriers, drivers and experiences of consultation, and organisation of care by practices with its challenges. Cognitive behaviour formulation analysed thematically will explore the development, maintenance and therapeutic opportunities for management in regular attenders. The feasibility, acceptability and utility of CBT for regular attendance will be examined.</p> <p>Discussion</p> <p>The health care costs, clinical needs, patient motivation for consultation and organisation of care for persistent frequent or regular attendance in primary care will be explored to develop training and policies for service providers. CBT for regular attendance will be piloted with a view to developing this approach as part of a multifaceted intervention.</p

A comparison of the radiosensitisation ability of 22 different element metal oxide nanoparticles using clinical megavoltage X-rays

Background: A wide range of nanoparticles (NPs), composed of different elements and their compounds, are being developed by several groups as possible radiosensitisers, with some already in clinical trials. However, no systematic experimental survey of the clinical X-ray radiosensitising potential of different element nanoparticles has been made. Here, we directly compare the irradiation-induced (10 Gy of 6-MV X-ray photon) production of hydroxyl radicals, superoxide anion radicals and singlet oxygen in aqueous solutions of the following metal oxide nanoparticles: Al2O3, SiO2, Sc2O3, TiO2, V2O5, Cr2O3, MnO2, Fe3O4, CoO, NiO, CuO, ZnO, ZrO2, MoO3, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb4O7, Dy2O3, Er2O3 and HfO2. We also examine DNA damage due to these NPs in unirradiated and irradiated conditions. Results: Without any X-rays, several NPs produced more radicals than water alone. Thus, V2O5 NPs produced around 5-times more hydroxyl radicals and superoxide radicals. MnO2 NPs produced around 10-times more superoxide anions and Tb4O7 produced around 3-times more singlet oxygen. Lanthanides produce fewer hydroxyl radicals than water. Following irradiation, V2O5 NPs produced nearly 10-times more hydroxyl radicals than water. Changes in radical concentrations were determined by subtracting unirradiated values from irradiated values. These were then compared with irradiation-induced changes in water only. Irradiation-specific increases in hydroxyl radical were seen with most NPs, but these were only significantly above the values of water for V2O5, while the Lanthanides showed irradiation-specific decreases in hydroxyl radical, compared to water. Only TiO2 showed a trend of irradiation-specific increase in superoxides, while V2O5, MnO2, CoO, CuO, MoO3 and Tb4O7 all demonstrated significant irradiation-specific decreases in superoxide, compared to water. No irradiation-specific increases in singlet oxygen were seen, but V2O5, NiO, CuO, MoO3 and the lanthanides demonstrated irradiation-specific decreases in singlet oxygen, compared to water. MoO3 and CuO produced DNA damage in the absence of radiation, while the highest irradiation-specific DNA damage was observed with CuO. In contrast, MnO2, Fe3O4 and CoO were slightly protective against irradiation-induced DNA damage. Conclusions: Beyond identifying promising metal oxide NP radiosensitisers and radioprotectors, our broad comparisons reveal unexpected differences that suggest the surface chemistry of NP radiosensitisers is an important criterion for their success

Analysis and characterization of heparin impurities

This review discusses recent developments in analytical methods available for the sensitive separation, detection and structural characterization of heparin contaminants. The adulteration of raw heparin with oversulfated chondroitin sulfate (OSCS) in 2007–2008 spawned a global crisis resulting in extensive revisions to the pharmacopeia monographs on heparin and prompting the FDA to recommend the development of additional physicochemical methods for the analysis of heparin purity. The analytical chemistry community quickly responded to this challenge, developing a wide variety of innovative approaches, several of which are reported in this special issue. This review provides an overview of methods of heparin isolation and digestion, discusses known heparin contaminants, including OSCS, and summarizes recent publications on heparin impurity analysis using sensors, near-IR, Raman, and NMR spectroscopy, as well as electrophoretic and chromatographic separations

An analysis of the three-dimensional kinetics and kinematics of maximal effort punches among amateur boxers.

This is an Accepted Manuscript of an article published by Taylor & Francis in International Journal of Performance Analysis in Sport on 27-9-18, available online: https://doi.org/10.1080/24748668.2018.1525651The purpose of this study was to quantify the 3D kinetics and kinematics of six punch types among amateur boxers. Fifteen males (age: 24.9 ± 4.2 years; stature: 1.78 ± 0.1 m; body mass: 75.3 ± 13.4 kg; boxing experience: 6.3 ± 2.8 years) performed maximal effort punches against a suspended punch bag during which upper body kinematics were assessed via a 3D motion capture system, and ground reaction forces (GRF) of the lead and rear legs via two force plates. For all variables except elbowjoint angular velocity, analysis revealed significant (P < 0.05) differences between straight, hook and uppercut punches. The lead hook exhibited the greatest peak fist velocity (11.95 ± 1.84 m/s), the jab the shortest delivery time (405 ± 0.15 ms), the rear uppercut the greatest shoulder-joint angular velocity (1069.8 ± 104.5°/s), and the lead uppercut the greatest elbow angular velocity (651.0 ± 357.5°/s). Peak resultant GRF differed significantly (P < 0.05) between rear and lead legs for the jab punch only. Whilst these findings provide novel descriptive data for coaches and boxers, future research should examine if physical and physiological capabilities relate to the key biomechanical qualities associated with maximal punching performance

Feasibility of a randomised controlled trial of remotely delivered problem-solving cognitive behaviour therapy versus usual care for young people with depression and repeat self-harm: lessons learnt (e-DASH)

BackgroundSelf-harm and depression are strong risk factors for repeat self-harm and suicide. We aimed to investigate the feasibility of a randomised controlled trial (RCT) of remotely delivered problem-solving cognitive behaviour therapy (PSCBT) plus treatment as usual (TAU) versus TAU in young people with repeat self-harm and depression.MethodsSingle-blind multi-centre RCT with an internal pilot, pre-set stop-go criteria and qualitative semi-structured interviews. Eligible participants (aged 16–30 years) were recruited from 9 adult or child and adolescent self-harm and crisis services; had ≥ 2 lifetime self-harm episodes, one in the preceding 96 h; and Beck Depression Inventory-II (BDI-II) score ≥ 17. Participants were randomised (1:1) to either TAU or TAU and 10–12 sessions of PSCBT delivered by mobile phone or video-calling.ResultsTwenty-two participants were recruited (11 in each arm), 10 (46%) completed follow-up at 6 months, 9 (82%) started the PSCBT and 4 (36%) completed it. The study did not meet three of its four stop-go criteria, reflecting considerable barriers to recruitment and retention. Participants had severe depression symptoms: with mean BDI-II 38.9 in the PSCBT and 37.2 in TAU groups, respectively. Three (14%) unblindings occurred for immediate safety concerns. Barriers to recruitment and retention included lack of agency for participants, severity of depression, recency of crisis with burden for participants and clinicians who diagnosed depression according to pervasiveness.ConclusionsRCTs of PSCBT for young people with depression and self-harm are not feasible using recruitment through mental health services that conduct assessments following self-harm presentations. Clinician assessment following self-harm presentation mainly identifies those with severe rather than mild-moderate depression

Membrane-Associated Heparan Sulfate Proteoglycan Is a Receptor for Adeno-Associated Virus Type 2 Virions

The human parvovirus adeno-associated virus (AAV) infects a broad range of cell types, including human, nonhuman primate, canine, murine, and avian. Although little is known about the initial events of virus infection, AAV is currently being developed as a vector for human gene therapy. Using defined mutant CHO cell lines and standard biochemical assays, we demonstrate that heparan sulfate proteoglycans mediate both AAV attachment to and infection of target cells. Competition experiments using heparin, a soluble receptor analog, demonstrated dose-dependent inhibition of AAV attachment and infection. Enzymatic removal of heparan but not chondroitin sulfate moieties from the cell surface greatly reduced AAV attachment and infectivity. Finally, mutant cell lines that do not produce heparan sulfate proteoglycans were significantly impaired for both AAV binding and infection. This is the first report that proteoglycan has a role in cellular attachment of a parvovirus. Together, these results demonstrate that membrane-associated heparan sulfate proteoglycan serves as the viral receptor for AAV type 2, and provide an explanation for the broad host range of AAV. Identification of heparan sulfate proteoglycan as a viral receptor should facilitate development of new reagents for virus purification and provide critical information on the use of AAV as a gene therapy vector