VESICULAR TRANSPORT. A structure of the COPI coat and the role of coat proteins in membrane vesicle assembly

Transport of material within cells is mediated by trafficking vesicles that bud from one cellular compartment and fuse with another. Formation of a trafficking vesicle is driven by membrane coats that localize cargo and polymerize into cages to bend the membrane. Although extensive structural information is available for components of these coats, the heterogeneity of trafficking vesicles has prevented an understanding of how complete membrane coats assemble on the membrane. We combined cryo-electron tomography, subtomogram averaging, and cross-linking mass spectrometry to derive a complete model of the assembled coat protein complex I (COPI) coat involved in traffic between the Golgi and the endoplasmic reticulum. The highly interconnected COPI coat structure contradicted the current "adaptor-and-cage" understanding of coated vesicle formation.

Ellipsometry with polarisation analysis at cryogenic temperatures inside a vacuum chamber

In this paper we describe a new variant of null ellipsometry to determine thicknesses and optical properties of thin films on a substrate at cryogenic temperatures. In the PCSA arrangement of ellipsometry the polarizer and the compensator are placed before the substrate and the analyzer after it. Usually, in the null ellipsometry the polarizer and the analyzer are rotated to find the searched minimum in intensity. In our variant we rotate the polarizer and the compensator instead, both being placed in the incoming beam before the substrate. Therefore the polarisation analysis of the reflected beam can be realized by an analyzer at fixed orientation. We developed this method for investigations of thin cryogenic films inside a vacuum chamber where the analyzer and detector had to be placed inside the cold shield at a temperature of T ≈ 90 K close to the substrate. All other optical components were installed at the incoming beam line outside the vacuum chamber, including all components which need to be rotated during the measurements. Our null ellipsometry variant has been tested with condensed krypton films on a highly oriented pyrolytic graphite substrate (HOPG) at a temperature of T ≈ 25 K. We show that it is possible to determine the indices of refraction of condensed krypton and of the HOPG substrate as well as thickness of krypton films with reasonable accuracy.

[Home-based infusion therapy--a feasible approach for chronically ill patients? A new path to provide superior patient care exemplified for Fabry's disease]

BACKGROUND

As there are scarce data from Germany addressing home-based infusion therapy in chronically ill patients, a study on transferring infusion therapy from in-patient-treatment to home care, exemplified for Fabry's disease, was conducted.

METHODS

A total of 69 patients on enzyme replacement infusion therapy (ERT with agalsidase alfa every two weeks) were enrolled in the open, non-controlled, multicentre, non-interventional observational study. After uneventful ERT in a hospital setting, intravenous treatment was administered at home by a specially-trained nurse. Primary outcome measure was change in patient satisfaction measured by an eleven-item Likert scale.

RESULTS

The in-home observation period lasted between 96 und 401 days (median 180; IQR 166-184). Patient satisfaction increased significantly with home-based therapy (p = 0.001). A quality of life analysis (SF-36) demonstrated significant improvements in role-physical (p = 0.003), bodily pain (p = 0.032), vitality (p < 0.001), social functioning (p = 0.020), role-emotional (p = 0.007), mental well-being (p = 0.007) and mental sum score (p = 0.002). Home infusions turned out to be safe and were well tolerated.

CONCLUSION

Chronically ill patients with need for regular infusion therapy may benefit from a home care setting. Home-based infusion therapy as exemplified by agalsidase alfa ERT in Fabry's disease is a viable option for patients who received uneventful infusions within the hospital.

Enzyme replacement therapy for alpha-mannosidosis: 12 months follow-up of a single centre, randomised, multiple dose study

BACKGROUND

Alpha-mannosidosis (OMIM 248500) is a rare lysosomal storage disease (LSD) caused by alpha-mannosidase deficiency. Manifestations include intellectual disabilities, facial characteristics and hearing impairment. A recombinant human alpha-mannosidase (rhLAMAN) has been developed for weekly intravenous enzyme replacement therapy (ERT). We present the preliminary data after 12 months of treatment.

METHODS

This is a phase I-II study to evaluate safety and efficacy of rhLAMAN. Ten patients (7-17 y) were treated. We investigated efficacy by testing motor function (6-minutes-Walk-Test (6-MWT), 3-min-Stair-Climb-Test (3-MSCT), The Bruininks-Oseretsky Test of Motor Proficiency (BOT2), cognitive function (Leiter-R), oligosaccharides in serum, urine and CSF and Tau- and GFA-protein in CSF.

RESULTS

Oligosaccharides: S-, U- and CSF-oligosaccharides decreased 88.6% (CI -92.0 -85.2, p < 0.001), 54.1% (CI -69.5- -38.7, p < 0,001), and 25.7% (CI -44.3- -7.1, p < 0.05), respectively. Biomarkers: CSF-Tau- and GFA-protein decreased 15%, p < 0.009) and 32.5, p < 0.001 respectively. Motor function: Improvements in 3MSCT (31 steps (CI 6.8-40.5, p < 0.01) and in 6MWT (60.4 m (CI -8.9 -51.1, NS) were achieved. Cognitive function: Improvement in the total Equivalence Age of 4 months (0.34) was achieved in the Leiter R test (CI -0.2-0.8, NS).

CONCLUSIONS

These data suggest that rhLAMAN may be an encouraging new treatment for patients with alpha-mannosidosis.The study is designed to continue for a total of 18 months. Longer-term follow-up of patients in this study and the future placebo-controlled phase 3 trial are needed to provide greater support for the findings in this study.

Review of clinical presentation and diagnosis of mucopolysaccharidosis IVA

Mucopolysaccharidosis type IVA (MPS IVA) was described in 1929 by Luis Morquio from Uruguay and James Brailsford from England, and was later found as an autosomal recessive lysosomal storage disease. MPS IVA is caused by mutations in the gene encoding the enzyme, N-acetylgalactosamine-6-sulfate sulfatase (GALNS). Reduced GALNS activity results in impaired catabolism of two glycosaminoglycans (GAGs), chondroitin-6-sulfate (C6S) and keratan sulfate (KS). Clinical presentations of MPS IVA reflect a spectrum of progression from a severe "classical" phenotype to a mild "attenuated" phenotype. More than 180 different mutations have been identified in the GALNS gene, which likely explains the phenotypic heterogeneity of the disorder. Accumulation of C6S and KS manifests predominantly as short stature and skeletal dysplasia (dysostosis multiplex), including atlantoaxial instability and cervical cord compression. However, abnormalities in the visual, auditory, cardiovascular, and respiratory systems can also affect individuals with MPS IVA. Diagnosis is typically based on clinical examination, skeletal radiographs, urinary GAG, and enzymatic activity of GALNS in blood cells or fibroblasts. Deficiency of GALNS activity is a common assessment for the laboratory diagnosis of MPS IVA; however, with recently increased availability, gene sequencing for MPS IVA is often used to confirm enzyme results. As multiple clinical presentations are observed, diagnosis of MPS IVA may require multi-system considerations. This review provides a history of defining MPS IVA and how the understanding of the disease manifestations has changed over time. A summary of the accumulated knowledge is presented, including information from the International Morquio Registry. The classical phenotype is contrasted with attenuated cases, which are now being recognized and diagnosed more frequently. Laboratory based diagnoses of MPS IVA are also discussed.

Transient increase of the energy gap of superconducting NbN thin films excited by resonant narrow-band terahertz pulses

Observations of radiation-enhanced superconductivity have thus far been limited to a few type-I superconductors (Al, Sn) excited at frequencies between the inelastic scattering rate and the superconducting gap frequency 2Δ/h. Utilizing intense, narrow-band, picosecond, terahertz pulses, tuned to just below and above 2Δ/h of a BCS superconductor NbN, we demonstrate that the superconducting gap can be transiently increased also in a type-II dirty-limit superconductor. The effect is particularly pronounced at higher temperatures and is attributed to radiation induced nonthermal electron distribution persisting on a 100 ps time scale.

[Joint preserving surgery of the adult hip: pelvic osteotomies]

Deformity and malposition of the acetabulum can occur during the development of the hip. Developmental hip dysplasia and acetabular retroversion are possible causes of osteoarthritis in the young adult. Surgical management with reorientation of the acetabulum allows causal therapy of the deformity and preservation of the native hip joint. Established techniques are the Bernese periacetabular osteotomy (PAO) and the Tönnis and Kalchschmidt triple osteotomy of the pelvis. Both techniques permit three-dimensional correction of the position of the acetabulum. Advantages and disadvantages of each technique must be considered and are summarized in the present paper. If performed early (osteoarthritis grade Tönnis 0 and 1) with correct indication and proper technique, good results can be expected.

Electrically driven nanopillars for THz quantum cascade lasers

In this work we present a rapid and parallel process for the fabrication of large scale arrays of electrically driven nanopillars for THz quantum cascade active media. We demonstrate electrical injection of pillars of 200 nm diameter and 2 µm height, over a surface of 1 mm(2). THz electroluminescence from the nanopillars is reported. This result is a promising step toward the realization of zero-dimensional structure for terahertz quantum cascade lasers.

Enzyme replacement therapy for mucopolysaccharidosis VI: long-term cardiac effects of galsulfase (Naglazyme®) therapy

Characteristic cardiac valve abnormalities and left ventricular hypertrophy are present in untreated patients with mucopolysaccharidosis type VI (MPS VI). Cardiac ultrasound was performed to investigate these findings in subjects during long-term enzyme replacement therapy (ERT) with recombinant human arylsulfatase B (rhASB, rhN-acetylgalactosamine 4-sulfatase, galsulfase, Naglazyme®). Studies were conducted in 54 subjects before ERT was begun and at specific intervals for up to 96 weeks of weekly infusions of rhASB at 1 mg/kg during phase 1/2, phase 2, and phase 3 trials of rhASB. At baseline, mitral and aortic valve obstruction was present and was significantly greater in those ≥12 years of age. Mild mitral and trace aortic regurgitation were present, the former being significantly greater in those <12 years. Left ventricular hypertrophy, with averaged z-scores ranging from 1.6-1.9 SD greater than normal, was present for ages both <12 and ≥12 years. After 96 weeks of ERT, ventricular septal hypertrophy regressed in those <12 years. For those ≥12 years, septal hypertrophy was unchanged, and aortic regurgitation increased statistically but not physiologically. Obstructive gradients across mitral and aortic valves remained unchanged. The results suggest that long-term ERT is effective in reducing intraventricular septal hypertrophy and preventing progression of cardiac valve abnormalities when administered to those <12 years of age.

Preparation methods to optimize the performance of sensor discs for fast chemiluminescence ozone analyzers

Fast ozone (O(3)) measurements (1-50 Hz) in the atmosphere are required for airborne studies and for the measurement of ground-based O(3) fluxes by the eddy covariance technique. Fast response analyzers, based on heterogeneous chemiluminescence, need dye coated sensor discs on which the chemiluminescence is generated. In this study, we present three new preparation methods for those sensor discs. Currently available sensor discs exhibit a fast temporal decay of sensitivity, resulting in short duty times which is troublesome for many field applications. To produce sensor discs that provide more stable signals over time, three dyes and nine energy transfer reagents were tested (as well as different stoichiometric mixtures). The resulting optimal method saves 80% of the solid chemicals and shows a duty ozone dose that is prolonged by a factor of 3.5, revealing the same average sensitivity as currently available discs. In addition, we observed a strong effect of the adsorption matrix on the O(3) sensitivity, although silica discs from the same manufacturer were used. Application of the new sensor discs during field measurements showed that the results are consistent with the laboratory data.

Dipole coupling of a double quantum dot to a microwave resonator

We demonstrate the realization of a hybrid solid-state quantum device, in which a semiconductor double quantum dot is dipole coupled to the microwave field of a superconducting coplanar waveguide resonator. The double dot charge stability diagram extracted from measurements of the amplitude and phase of a microwave tone transmitted through the resonator is in good agreement with that obtained from transport measurements. Both the observed frequency shift and linewidth broadening of the resonator are explained considering the double dot as a charge qubit coupled with a strength of several tens of MHz to the resonator.

Energy-gap dynamics of superconducting NbN thin films studied by time-resolved terahertz spectroscopy

Using time-domain terahertz spectroscopy we performed direct studies of the photoinduced suppression and recovery of the superconducting gap in a conventional BCS superconductor NbN. Both processes are found to be strongly temperature and excitation density dependent. The analysis of the data with the established phenomenological Rothwarf-Taylor model enabled us to determine the bare quasiparticle recombination rate, the Cooper pair-breaking rate and the electron-phonon coupling constant, λ=1.1±0.1, which is in excellent agreement with theoretical estimates.

[Development of diagnosis-related groups in different surgical disciplines]

BACKGROUND

Since the introduction of Diagnosis-Re-lat-ed Groups (DRGs) in Germany, the variables of remuneration have continuously changed. Subjectively, reimbursement by DRG has a negative connotation among all specialities. We analysed the development of reimbursement and length of stay in different surgical specialties.

MATERIAL AND METHODS

By grouping the top-10-diagnoses and therapies in hand surgery, trauma surgery, general surgery as well as cardiothoracic and vascular surgery between 2004 and 2010, DRGs were obtained, compared and the data deduced.

RESULTS

While the lower threshold of length of stay remained almost the same, mean value and upper threshold became shorter in most of the top-10-diagnoses. During the observation period, total reimbursement increased by 30 % in hand surgery, 20 % in general surgery and 17 % in cardiothoracic and vascular surgery, while in trauma surgery it decreased by 1 %. This corresponds to mean annual growth rates of 4.47 %, 3.08 %, 2.68 % and - 0.15 %, respectively. No correlation was found between the 4 disciplines and macro-economic parameters.

CONCLUSION

Reductions of mean and upper thresholds of length of stay are present in all surgical disciplines. Total reimbursements developed partially in a contradictory manner. Negative growth involves the danger that hospital investments cannot be realised, especially in the presence of high personnel costs.

Neuropsychiatric symptoms and brain structural alterations in Fabry disease

BACKGROUND

Neuropsychiatric symptoms (NPS), mainly cognitive deficits up to dementia and depressive syndromes have been described repeatedly in Fabry disease (FD). However, examinations regarding the pattern, extent, and frequency of the NPS in FD are still lacking. Moreover, the relationship between NPS and brain structural alterations in FD is unknown. The aim of this study was 1) to characterize NPS in a relatively large cohort of adult subjects with FD, and 2) to explore the association of cognitive performance and depressive syndromes with the FD-typical brain structural findings.

METHODS

Twenty-five Fabry patients (age 36.5 ± 11.0) with mild to moderate disease involvement and 20 age, gender-, and education-matched healthy controls were extensively studied by neuropsychiatric assessment, structural magnetic resonance imaging, magnetic resonance angiography, and diffusion-tensor imaging.

RESULTS

Patients with FD showed deficits only in the attention domain. Clinically relevant depressive syndromes were noted in 60% of the patients. The subgroup of patients with markedly elevated volumes of white matter lesions (not associated with actual stroke; n=7) showed slightly more learning and memory deficits, but no higher depression rate compared to less affected patients.

CONCLUSIONS

Against the prevailing assumption, Fabry patients, even those with marked brain structural alterations, showed only mild cognitive deficits. The high frequency of depression in FD is likely to be related to the burden of this chronic multiorganic hereditary disease, but not to the FD-typical brain structural alterations. Longitudinal studies are necessary to clear, if the mild cognitive deficits in FD might precede clinically relevant cognitive decline.

Safety of agalsidase alfa in patients with Fabry disease under 7 years

AIM

To evaluate the safety and explore the efficacy of enzyme replacement therapy (ERT) for Fabry disease with agalsidase alfa in young children enrolled in the Fabry Outcome Survey (FOS).

METHODS

This retrospective chart review identified eight children (mean age= 5.0±1.6 [mean ±SD]) in FOS who began treatment with agalsidase alfa (0.2 mg/kg, i.v., every other week) when <7 years old. Vital signs and adverse events were monitored throughout the study period. Glomerular filtration rate (GFR) was estimated, and left ventricular mass indexed to height(2.7) (LVMi) was assessed with echocardiography. Patients received 1.2-6.7 years of treatment (mean=4.2 years).

RESULTS

Infusion reactions occurred in three patients and were of mild or moderate severity. IgG antibodies to agalsidase alfa were found in one patient who experienced two mild and one moderate infusion reactions. Mean GFR was within the normal range at baseline and remained normal. LVMi was above the 75th percentile of age-matched children in 5 of 6 patients evaluated at baseline. Only two patients exceeded this threshold at their last assessment.

CONCLUSION

Long-term observation will be needed to determine whether early initiation of ERT will prevent major organ dysfunction in these patients.