Quantifying Beta-Galactosylceramide Kinetics in Cerebrospinal Fluid of Healthy Subjects Using Deuterium Labeling

Therapeutics promoting myelin synthesis may enhance recovery in demyelinating diseases, such as multiple sclerosis. However, no suitable method exists to quantify myelination. The turnover of galactosylceramide (myelin component) is indicative of myelination in mice, but its turnover has not been determined in humans. Here, six healthy subjects consumed 120 mL 70% D₂O daily for 70 days to label galactosylceramide. We then used mass spectrometry and compartmental modeling to quantify the turnover rate of galactosylceramide in cerebrospinal fluid. Maximum deuterium enrichment of body water ranged from 1.5–3.9%, whereas that of galactosylceramide was much lower: 0.05–0.14%. This suggests a slow turnover rate, which was confirmed by the model‐estimated galactosylceramide turnover rate of 0.00168 day⁻¹, which corresponds to a half‐life of 413 days. Additional studies in patients with multiple sclerosis are needed to investigate whether galactosylceramide turnover could be used as an outcome measure in clinical trials with remyelination therapies.

Levofloxacin-Induced QTc Prolongation Depends on the Time of Drug Administration

Understanding the factors influencing a drug's potential to prolong the QTc interval on an electrocardiogram is essential for the correct evaluation of its safety profile. To explore the effect of dosing time on drug‐induced QTc prolongation, a randomized, crossover, clinical trial was conducted in which 12 healthy male subjects received levofloxacin at 02:00, 06:00, 10:00, 14:00, 18:00, and 22:00. Using a pharmacokinetic‐pharmacodynamic (PK‐PD) modeling approach to account for variations in PKs, heart rate, and daily variation in baseline QT, we find that the concentration‐QT relationship shows a 24‐hour sinusoidal rhythm. Simulations show that the extent of levofloxacin‐induced QT prolongation depends on dosing time, with the largest effect at 14:00 (1.73 (95% prediction interval: 1.56–1.90) ms per mg/L) and the smallest effect at 06:00 (−0.04 (−0.19 to 0.12) ms per mg/L). These results suggest that a 24‐hour variation in the concentration‐QT relationship could be a potentially confounding factor in the assessment of drug‐induced QTc prolongation.

Quality of life in a trial of short stretch versus four-layer bandaging in the management of chronic venous ulceration

Objective: To evaluate health-related quality of life (HRQoL) in a prospective randomized trial of patients suffering from venous ulceration comparing a generic four-layer elastic bandage (4LB) with a new cohesive short stretch bandage system (CSSB).

Methods: Randomized prospective open parallel groups trial in community leg ulcer clinics within twelve trusts in England and Northern Ireland. Patients newly presenting for treatment suffering from chronic venous ulceration, with ankle brachial pressure index (ABPI) >0.8 were entered into the trial. Patients were asked to complete the Nottingham Health Profile (NHP) at entry, at end of trial period (withdrawal or healing), and at 24 weeks. Principal analysis was the comparison of final NHP scores using linear regression with baseline scores entered as a covariate.

Results: In all, 154 of the 156 patients who entered the trial completed the initial questionnaire, with 139/154 (90.2%) patients completing at least one follow-up questionnaire. Improvements were noted for all scores after 24 weeks. The improvements were significantly greater in the 114 patients whose ulcers had healed compared with the 40 whose ulcers remained open in the domains of bodily pain (mean difference [d]=13.2, 95% CI 3.6-22.9, P =0.008), emotional reactions (d=10.5, 95% CI 2.8-18.1, P =0.007) and social isolation (d=8.5, 95% CI 1.2-15.9, P =0.024). There were similar mean scores between the 72 patients treated with the 4LB and the 82 patients treated with CSSB for all domains of the NHP, the largest adjusted difference favoured CSSB for energy (d=3.6, 95% CI-4.3-11.4, P =0.37).

Conclusions: Patients suffering from leg ulceration show improvements in perceived health following effective ulcer management. The two bandage systems achieved similar improvements in perceived health over 24 weeks.

The NSW brain tissue resource centre: Banking for alcohol and major neuropsychiatric disorders research

The New South Wales Brain Tissue Resource Centre (NSWBTRC) at the University of Sydney (Australia) is an established human brain bank providing tissue to the neuroscience research community for investigations on alcohol-related brain damage and major psychiatric illnesses such as schizophrenia. The NSWBTRC relies on wide community engagement to encourage those with and without neuropsychiatric illness to consent to donation through its allied research programs. The subsequent provision of high-quality samples relies on standardized operational protocols, associated clinical data, quality control measures, integrated information systems, robust infrastructure, and governance. These processes are continually augmented to complement the changes in internal and external governance as well as the complexity and diversity of advanced investigation techniques. This report provides an overview of the dynamic process of brain banking and discusses the challenges of meeting the future needs of researchers, including synchronicity with other disease-focus collections.

Prediction of percent body fat measurements in Americans 8 years and older

BACKGROUND/OBJECTIVES

Although numerous equations to predict percent body fat have been published, few have broad generalizability. The objective of this study was to develop sets of equations that are generalizable to the American population 8 years of age and older.

SUBJECTS/METHODS

Dual-emission X-ray absorptiometry (DXA) assessed percent body fat from the 1999-2006 National Health and Nutrition Examination Survey (NHANES) was used as the response variable for development of 14 equations for each gender that included between 2 and 10 anthropometrics. Other candidate variables included demographics and menses. Models were developed using the Least Absolute Shrinkage and Selection Operator (LAASO) and validated in a ¼ withheld sample randomly selected from 11 884 males or 9215 females.

RESULTS

In the final models, R(2) ranged from 0.664 to 0.845 in males and from 0.748 to 0.809 in females. R(2) was not notably improved by development of equations within, rather than across, age and ethnic groups. Systematic over or under estimation of percent body fat by age and ethnic groups was within 1 percentage point. Seven of the fourteen gender-specific models had R(2) values above 0.80 in males and 0.795 in females and exhibited low bias by age, race/ethnicity and body mass index (BMI).

CONCLUSIONS

To our knowledge, these are the first equations that have been shown to be valid and unbiased in both youth and adults in estimating DXA assessed body fat. The equations developed here are appropriate for use in multiple ethnic groups, are generalizable to the US population and provide a useful method for assessment of percent body fat in settings where methods such as DXA are not feasible.

Mass Measurement of 56Sc Reveals a Small A = 56 Odd-Even Mass Staggering, Implying a Cooler Accreted Neutron Star Crust

We present the mass excesses of (52-57)Sc, obtained from recent time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory at Michigan State University. The masses of 56Sc and 57Sc were determined for the first time with atomic mass excesses of -24.85(59)((-54)(+0))  MeV and -21.0(1.3)  MeV, respectively, where the asymmetric uncertainty for 56Sc was included due to possible contamination from a long-lived isomer. The 56Sc mass indicates a small odd-even mass staggering in the A = 56 mass chain towards the neutron drip line, significantly deviating from trends predicted by the global FRDM mass model and favoring trends predicted by the UNEDF0 and UNEDF1 density functional calculations. Together with new shell-model calculations of the electron-capture strength function of 56Sc, our results strongly reduce uncertainties in model calculations of the heating and cooling at the 56Ti electron-capture layer in the outer crust of accreting neutron stars. We find that, in contrast to previous studies, neither strong neutrino cooling nor strong heating occurs in this layer. We conclude that Urca cooling in the outer crusts of accreting neutron stars that exhibit superbursts or high temperature steady-state burning, which are predicted to be rich in A≈56 nuclei, is considerably weaker than predicted. Urca cooling must instead be dominated by electron capture on the small amounts of adjacent odd-A nuclei contained in the superburst and high temperature steady-state burning ashes. This may explain the absence of strong crust Urca cooling inferred from the observed cooling light curve of the transiently accreting x-ray source MAXI J0556-332.

Theoretical calculations of rotationally inelastic collisions of He with NaK(A (1)Σ(+)): Transfer of population, orientation, and alignment

We have performed extensive calculations to investigate thermal energy, rotationally inelastic collisions of NaK (A(1)Σ(+)) with He. We determined a potential energy surface using a multi-reference configuration interaction wave function as implemented by the GAMESS electronic structure code, and we have performed coupled channel scattering calculations using the Arthurs and Dalgarno formalism. We also calculate the Grawert coefficients B(λ)(j, j') for each j → j' transition. These coefficients are used to determine the probability that orientation and alignment are preserved in collisions taking place in a cell environment. The calculations include all rotational levels with j or j' between 0 and 50, and total (translational and rotational) energies in the range 0.0002-0.0025 a.u. (∼44-550 cm(-1)). The calculated cross sections for transitions with even values of Δj tend to be larger than those for transitions with odd Δj, in agreement with the recent experiments of Wolfe et al. (J. Chem. Phys. 134, 174301 (2011)). The calculations of the energy dependence of the cross sections and the calculations of the fraction of orientation and alignment preserved in collisions also exhibit distinctly different behaviors for odd and even values of Δj. The calculations also indicate that the average fraction of orientation or alignment preserved in a transition becomes larger as j increases. We interpret this behavior using the semiclassical model of Derouard, which also leads to a simple way of visualizing the distribution of the angles between the initial and final angular momentum vectors j and j'. Finally, we compare the exact quantum results for j → j' transitions with results based on the simpler, energy sudden approximation. That approximation is shown to be quite accurate.

Mass measurements demonstrate a strong N=28 shell gap in argon

We present results from recent time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory at Michigan State University. We report the first mass measurements of ^{48}Ar and ^{49}Ar and find atomic mass excesses of -22.28(31)  MeV and -17.8(1.1)  MeV, respectively. These masses provide strong evidence for the closed shell nature of neutron number N=28 in argon, which is therefore the lowest even-Z element exhibiting the N=28 closed shell. The resulting trend in binding-energy differences, which probes the strength of the N=28 shell, compares favorably with shell-model calculations in the sd-pf shell using SDPF-U and SDPF-MU Hamiltonians.

[Auto-immune disorders as a possible cause of neuropsychiatric syndromes]

BACKGROUND

Changes that occur in the behaviour of voltage-gated ion channels and ligand-gated receptor channels due to gene mutations or auto-immune attack are the cause of channelopathies in the central and peripheral nervous system. Although the relation between molecular channel defects and clinical symptoms has been explained in the case of many neuromuscular channelopathies, the pathophysiology of auto-immunity in neuropsychiatric syndromes is still unclear.

AIM

To review recent findings regarding neuronal auto-immune reactions in severe neuropsychiatric syndromes.

METHOD

Using PubMed, we consulted the literature published between 1990 and August 2014 relating to the occurrence of auto-immune antibodies in severe and persistent neuropsychiatric syndromes.

RESULTS

Auto-antibodies have only limited access to the central nervous system, but if they do enter the system they can, in some cases, cause disease. We discuss recent findings regarding the occurrence of auto-antibodies against ligand-activated receptor channels and potassium channels in neuropsychiatric and neurological syndromes, including schizophrenia and limbic encephalitis.

CONCLUSION

Although the occurrence of several auto-antibodies in schizophrenia has been confirmed, there is still no proof of a causal relationship in the syndrome. We still have no evidence of the prevalence of auto-immunity in neuropsychiatric syndromes. The discovery that an antibody against an ion channel is associated with some neuropsychiatric disorders may mean that in future it will be possible to treat patients by means of immunosuppression, which could lead to an improvement in a patient's cognitive abilities.

The art and science of chronic disease management come together in a lifestyle-focused approach to primary care

Changes in patterns of living result in changes in the nature and causes of disease. The industrial revolution of the late 18th century, and the technological revolution of the late 20th century are cases in point. The former was associated with a decline in infectious diseases; the latter with an increase in lifestyle and environmentally induced chronic diseases . Health practices are typically modified to deal with such changes, hence the recent rise in interest in lifestyle-oriented forms of clinical practice.

Determining the rp-process flow through 56Ni: resonances in 57Cu(p,γ)58Zn identified with GRETINA

An approach is presented to experimentally constrain previously unreachable (p, γ) reaction rates on nuclei far from stability in the astrophysical rp process. Energies of all critical resonances in the (57)Cu(p,γ)(58)Zn reaction are deduced by populating states in (58)Zn with a (d, n) reaction in inverse kinematics at 75 MeV/u, and detecting γ-ray-recoil coincidences with the state-of-the-art γ-ray tracking array GRETINA and the S800 spectrograph at the National Superconducting Cyclotron Laboratory. The results reduce the uncertainty in the (57)Cu(p,γ) reaction rate by several orders of magnitude. The effective lifetime of (56)Ni, an important waiting point in the rp process in x-ray bursts, can now be determined entirely from experimentally constrained reaction rates.

Obesity Paradox should not interfere with public health efforts

The Obesity Paradox could result in confusing messages that derail beneficial environmental changes and lead to reduced efforts by physicians to provide healthy lifestyle treatment plans to their obese patients. The Obesity Paradox applies in the main to individuals who have a disease, and therefore observed associations with mortality illustrating the Paradox may be more susceptible to certain types of bias than would be found in healthy individuals. Although individualization of weight loss advice for patients with serious disease is appropriate in medical settings, this does not supplant the need for general efforts to prevent and treat obesity.

Clonal heterogeneity of thymic B cells from early-onset myasthenia gravis patients with antibodies against the acetylcholine receptor

Myasthenia gravis (MG) with antibodies against the acetylcholine receptor (AChR-MG) is considered as a prototypic autoimmune disease. The thymus is important in the pathophysiology of the disease since thymus hyperplasia is a characteristic of early-onset AChR-MG and patients often improve after thymectomy. We hypothesized that thymic B cell and antibody repertoires of AChR-MG patients differ intrinsically from those of control individuals. Using immortalization with Epstein-Barr Virus and Toll-like receptor 9 activation, we isolated and characterized monoclonal B cell lines from 5 MG patients and 8 controls. Only 2 of 570 immortalized B cell clones from MG patients produced antibodies against the AChR (both clones were from the same patient), suggesting that AChR-specific B cells are not enriched in the thymus. Surprisingly, many B cell lines from both AChR-MG and control thymus samples displayed reactivity against striated muscle proteins. Striational antibodies were produced by 15% of B cell clones from AChR-MG versus 6% in control thymus. The IgVH gene sequence analysis showed remarkable similarities, concerning VH family gene distribution, mutation frequency and CDR3 composition, between B cells of AChR-MG patients and controls. MG patients showed clear evidence of clonal B cell expansion in contrast to controls. In this latter aspect, MG resembles multiple sclerosis and clinically isolated syndrome, but differs from systemic lupus erythematosus. Our results support an antigen driven immune response in the MG thymus, but the paucity of AChR-specific B cells, in combination with the observed polyclonal expansions suggest a more diverse immune response than expected.