Diffusion of macromolecules in a polymer hydrogel: from microscopic to macroscopic scales.

To gain insight into the fundamental processes determining the motion of macromolecules in polymeric matrices, the dynamical hindrance of polymeric dextran molecules diffusing as probe through a polyacrylamide hydrogel is systematically explored. Three complementary experimental methods combined with Brownian dynamics simulations are used to study a broad range of dextran molecular weights and salt concentrations. While multi-parameter fluorescence image spectroscopy (MFIS) is applied to investigate the local diffusion of single molecules on a microscopic length scale inside the hydrogel, a macroscopic transmission imaging (MTI) fluorescence technique and nuclear magnetic resonance (NMR) are used to study the collective motion of dextrans on the macroscopic scale. These fundamentally different experimental methods, probing different length scales of the system, yield long-time diffusion coefficients for the dextran molecules which agree quantitatively. The measured diffusion coefficients decay markedly with increasing molecular weight of the dextran and fall onto a master curve. The observed trends of the hindrance factors are consistent with Brownian dynamics simulations. The simulations also allow us to estimate the mean pore size for the herein investigated experimental conditions. In addition to the diffusing molecules, MFIS detects temporarily trapped molecules inside the matrix with diffusion times above 10 ms, which is also confirmed by anisotropy analysis. The fraction of bound molecules depends on the ionic strength of the solution and the charge of the dye. Using fluorescence intensity analysis, also MTI confirms the observation of the interaction of dextrans with the hydrogel. Moreover, pixelwise analysis permits to show significant heterogeneity of the gel on the microscopic scale.

[Intersectoral pain treatment. The Algesiologikum group]. / Sektorübergreifende schmerzmedizinische Versorgung. Der Algesiologikum-Verbund.

Cross-sectoral clinical pathways for chronic pain patients in standard and routine care are a major challenge for the German healthcare system. The Algesiologikum group has developed such clinical pathways including an essential infrastructure. Cooperation partners of the Algesiologikum group are two outpatient medical care units, one neurosurgery practice and four hospitals. In the outpatient sector as well as in the inpatient sector the Algesiologikum group provides a multidisciplinary team caring for chronic pain patients. The range of treatment in the hospitals includes multimodal, invasive and surgical pain therapy. The present report illustrates possibilities and frontiers of the Algesiologikum concept based on all patients treated since 2009.

[Are members of fibromyalgia syndrome self-help groups "different"? Demographic and clinical characteristics of members and non-members of fibromyalgia syndrome self-help groups]. / Sind Mitglieder von Fibromyalgiesyndrom-Selbsthilfegruppen "anders"? Demografische und klinische Charakteristika von Mitgliedern und Nicht-Mitgliedern von Fibromyalgiesyndrom-Selbsthilfegruppen.

BACKGROUND: No data were available on demographic and clinical characteristics of members of fibromyalgia syndrome (FMS) self-help groups in Germany. MATERIAL AND METHODS: The study was carried out from November 2010 to April 2011. A set of questionnaires was distributed by the German League Against Rheumatism and the German Fibromyalgia Association to members and to all consecutive FMS patients at nine clinical centres of different levels of care. The set included a self-developed questionnaire on demographic and medical data and on previously and currently used therapies, the patient health questionnaire (PHQ 4) and the fibromyalgia survey questionnaire. RESULTS: Members of FMS self-help groups (N = 1,014) were older and reported a longer duration of chronic widespread pain, less anxiety and depression and a more frequent current use of aerobic exercise, relaxation training and complementary alternative medication than participants not affiliated with FMS self-help groups (N = 630). CONCLUSIONS: Membership in FMS self-help groups was associated with less psychological distress and a more frequent use of active self-management strategies.

[German fibromyalgia consumer reports. Benefits and harms of fibromyalgia syndrome therapies]. / Der deutsche Fibromyalgieverbraucherbericht. Nutzen und Schaden von Behandlungen des Fibromyalgiesyndroms.

BACKGROUND: Consumer reports provide information on benefits and harms in routine clinical care. We report the first fibromyalgia syndrome (FMS) consumer reports in Europe. MATERIAL AND METHODS: The study was carried out from November 2010 to April 2011. The benefits and harms of pharmacological and non-pharmacological therapies experienced by the patient were assessed in an 11-point Likert scale (0=no, 10=very high benefit or harm) by a questionnaire. The questionnaire was distributed by the German League against Rheumatism and the German Fibromyalgia Association to their members and to all consecutive FMS patients of nine clinical centers of different levels of care. RESULTS: A total of 1,661 questionnaires (95% women, mean age 54 years) were analyzed. Self-management strategies (distraction, resting, aerobic exercise), physical therapies (warm and pool therapies), psychological therapies (education, psychotherapy), and inpatient multicomponent therapies were judged to be more efficacious and less harmful than all types of pharmacological therapies. CONCLUSION: The German fibromyalgia consumer reports highlight the importance of non-pharmcological therapies in the long-term management of FMS.

[German pain questionnaire and standardised documentation with the KEDOQ-Schmerz. A way for quality management in pain therapy]. / Deutscher Schmerzfragebogen (DSF) und standardisierte Dokumentation mit KEDOQ-Schmerz. Auf dem Weg zur gemeinsamen Qualitätsentwicklung der Schmerztherapie.

KEDOQ-Schmerz was developed by the German Pain Society (formerly DGSS) as a basic tool for documentation and quality management of pain therapy. It is planned to use KEDOQ-Schmerz as the data basis for nationwide, cross-sectional and independent scientific research in health services in Germany. With comparatively little effort, each participating institution (practices, pain clinics) will be able to provide quality control of their own diagnostic procedures and therapeutic effects by using benchmarking. In future KEDOQ-Schmerz will also be used as a method for external quality management in pain therapy in Germany.

[Epidural spinal cord stimulation for therapy of chronic pain. Summary of the S3 guidelines]. / Epidurale Rückenmarkstimulation zur Therapie chronischer Schmerzen. Zusammenfassung der S3-Leitlinie.

Epidural spinal cord stimulation (SCS) is a reversible but invasive procedure which should be used for neuropathic pain, e.g. complex regional pain syndrome I (CRPS) and for mostly chronic radiculopathy in connection with failed back surgery syndrome following unsuccessful conservative therapy. Epidural SCS can also successfully be used after exclusion of curative procedures and conservative therapy attempts for vascular-linked pain, such as in peripheral arterial occlusive disease stages II and III according to Fontaine and refractory angina pectoris. Clinical practice has shown which clinical symptoms cannot be successfully treated by epidural SCS, e.g. pain in complete paraplegia syndrome or atrophy/injury of the sensory pathways of the spinal cord or cancer pain. A decisive factor is a critical patient selection as well as the diagnosis. Epidural SCS should always be used within an interdisciplinary multimodal therapy concept. Implementation should only be carried out in experienced therapy centers which are in a position to deal with potential complications.

[Identification and grouping of pain patients according to claims data]. / Identifikation und Gruppierung von Schmerzpatienten anhand von Routinedaten einer Krankenkasse.

The ICD classification does not provide the opportunity to adequately identify pain patients. Therefore we developed an alternative method for the identification and classification of pain patients which is based on prescription and diagnoses data from the year 2006 of one nationwide sickness fund (DAK) and which is led by two main assumptions: 1. Beneficiaries without prescription of an analgetic drug but with a diagnosis pattern that is characteristic of patients who are treated with opioids are also likely to be pain patients. 2. Each combination of diagnosis groups can be traced back to one primary diagnosis out of a diagnosis group according to the patient classification system CCS (Clinical Classifications Software). The selection of this diagnosis group (CCS) allows for the allocation of the beneficiary to only one pain type. As a result we identified 65 combinations of CCS diagnosis groups--aggregated to nine "CCS pain types"--to which 77.1% of all patients with at least two opioid prescriptions can be allocated: 26.3% to pain due to arthrosis, 18.0% to pain due to intervertebral disc illnesses, 13.1% to other specific back pain, 6.7% to neuropathic pain, 4.5% to unspecific back pain, 4.2% to headache, 2.4% to pain after traumatic fractures, 1.3% to pain of multimorbid, high-maintenance patients, and 0.6% to cancer pain. Based on our method beneficiaries who have a high probability of suffering from moderate to strong pain can be identified and included in further claims data analyses of health care delivery and utilization pattern of pain-related disorders in Germany.

Neural correlates of subjective arousal and valence in health and panic disorder.

Aberrant emotion processing is a core characteristic of panic disorder (PD). Findings concerning the underlying neural pathways remain inconsistent. We applied functional magnetic resonance imaging (fMRI) in the context of a task based on the circumplex model of affect. This model links affective states to two underlying neurophysiological systems: arousal and valence. Twenty-two healthy participants and 20 participants with PD rated arousal and valence in response to affective faces during fMRI. In healthy controls, we found that arousal modulated the hemodynamic response in the parahippocampus, the ventromedial prefrontal cortex and the cuneus during face perception. Valence and extreme ratings of valence modulated the hemodynamic response in temporal, parietal, somatosensory, premotor and cerebellar regions. Comparing healthy controls to participants with PD, we found that healthy controls showed a stronger modulation of the hemodynamic response during face perception associated with extreme ratings of valence in the parahippocampus and the supplementary motor area. This suggests parahippocampal dysfunction in the processing of highly valenced affective faces in PD, which may underlie aberrant contextualization of strong affective stimuli. Our findings need to be interpreted with care as they were adjusted for multiple comparisons using a liberal correction procedure.

The neural networks underlying auditory sensory gating.

One of the most consistent electrophysiological deficits reported in the schizophrenia literature is the failure to inhibit, or properly gate, the neuronal response to the second stimulus of an identical pair (i.e., sensory gating). Although animal and invasive human studies have consistently implicated the auditory cortex, prefrontal cortex and hippocampus in mediating the sensory gating response, localized activation in these structures has not always been reported during non-invasive imaging modalities. In the current experiment, event-related FMRI and a variant of the traditional gating paradigm were utilized to examine how the gating network differentially responded to the processing of pairs of identical and non-identical tones. Two single-tone conditions were also presented so that they could be used to estimate the HRF for paired stimuli, reconstructed based on actual hemodynamic responses, to serve as a control non-gating condition. Results supported an emerging theory that the gating response for both paired-tone conditions was primarily mediated by auditory and prefrontal cortex, with potential contributions from the thalamus. Results also indicated that the left auditory cortex may play a preferential role in determining the stimuli that should be inhibited (gated) or receive further processing due to novelty of information. In contrast, there was no evidence of hippocampal involvement, suggesting that future work is needed to determine what role it may play in the gating response.

Structural evidence for evolution of the beta/alpha barrel scaffold by gene duplication and fusion.

The atomic structures of two proteins in the histidine biosynthesis pathway consist of beta/alpha barrels with a twofold repeat pattern. It is likely that these proteins evolved by twofold gene duplication and gene fusion from a common half-barrel ancestor. These ancestral domains are not visible as independent domains in the extant proteins but can be inferred from a combination of sequence and structural analysis. The detection of subdomain structures may be useful in efforts to search genome sequences for functionally and structurally related proteins.

Conservation of the Chk1 checkpoint pathway in mammals: linkage of DNA damage to Cdk regulation through Cdc25.

In response to DNA damage, mammalian cells prevent cell cycle progression through the control of critical cell cycle regulators. A human gene was identified that encodes the protein Chk1, a homolog of the Schizosaccharomyces pombe Chk1 protein kinase, which is required for the DNA damage checkpoint. Human Chk1 protein was modified in response to DNA damage. In vitro Chk1 bound to and phosphorylated the dual-specificity protein phosphatases Cdc25A, Cdc25B, and Cdc25C, which control cell cycle transitions by dephosphorylating cyclin-dependent kinases. Chk1 phosphorylates Cdc25C on serine-216. As shown in an accompanying paper by Peng et al. in this issue, serine-216 phosphorylation creates a binding site for 14-3-3 protein and inhibits function of the phosphatase. These results suggest a model whereby in response to DNA damage, Chk1 phosphorylates and inhibits Cdc25C, thus preventing activation of the Cdc2-cyclin B complex and mitotic entry.

Mitotic and G2 checkpoint control: regulation of 14-3-3 protein binding by phosphorylation of Cdc25C on serine-216.

Human Cdc25C is a dual-specificity protein phosphatase that controls entry into mitosis by dephosphorylating the protein kinase Cdc2. Throughout interphase, but not in mitosis, Cdc25C was phosphorylated on serine-216 and bound to members of the highly conserved and ubiquitously expressed family of 14-3-3 proteins. A mutation preventing phosphorylation of serine-216 abrogated 14-3-3 binding. Conditional overexpression of this mutant perturbed mitotic timing and allowed cells to escape the G2 checkpoint arrest induced by either unreplicated DNA or radiation-induced damage. Chk1, a fission yeast kinase involved in the DNA damage checkpoint response, phosphorylated Cdc25C in vitro on serine-216. These results indicate that serine-216 phosphorylation and 14-3-3 binding negatively regulate Cdc25C and identify Cdc25C as a potential target of checkpoint control in human cells.

An unusual cause of traumatic reticulitis/reticuloperitonitis in a herd of Swiss dairy cows nearby an airport.

This report describes the findings in five cows from one dairy herd, in which all 31 cows were slaughtered or euthanised because of traumatic reticuloperitonitis. All the cows had numerous thin sharp pieces of metal attached to a magnet in the reticulum, giving the magnet a hedgehog-like appearance. Investigation revealed that the cattle had eaten forage harvested from a field immediately adjacent to an airport. The snow was cleared from the airport runways with a machine that had a wire-bristle brush attachment. Mechanical wear resulted in numerous wire bristles breaking and these were blown with the snow onto the field in question. The wire then became accidentally incorporated into the hay and grass silage at harvest the next summer and was ingested by the cattle in the fall and winter. To prevent further cases, approximately 200 tonnes of hay and grass silage contaminated with wire were discarded and 30 hectares of the 50-hectare field were cultivated and re-sown. The wire-bristles of the snow plow were replaced with plastic bristles. The cost of this and the livestock loss was several hundred thousand Swiss Francs.

Intravenous lipid infusion in the successful resuscitation of local anesthetic-induced cardiovascular collapse after supraclavicular brachial plexus block.

We describe a case of successful resuscitation with an i.v. lipid infusion of local anesthetic-induced cardiovascular toxicity after supraclavicular brachial plexus block with mepivacaine and bupivacaine. Lipid therapy was initiated after 10 min of unsuccessful resuscitation and resulted in restoration of cardiovascular activity and hemodynamic stability. This case illustrates the utility of i.v. lipid therapy in the treatment of local anesthetic toxicity.

Extraction of Aortic Knuckle Contour in Chest Radiographs Using Deep Learning.

In this paper, we aim to extract the aortic knuckle (AK) contour in chest radiographs, an anatomical structure rarely being addressed in the literature. Since the AK structure is small and thin, simply adopting the deep network methods that are successful for large organ segmentation is inadequate for achieving good pixel-level accuracy and resolving local ambiguities. To address this challenge, we propose a new coarse-to-fine segmentation approach which focuses on global and local information contexts, respectively. Two convolutional networks are used. For the coarse segmentation, we use FasterRCNN; for the fine segmentation, we use U-Net. Our evaluation uses the publicly available JSRT dataset; the results are promising. Besides presenting these results, we analyze issues such as the imprecision of manual contour marking, and automatic generation of the coarse segmentation ground-truth mask used for deep network training. Our approach is general and can be applied to extract other curve-like objects-of-interest.

ABRF ESRG 2006 study: Edman sequencing as a method for polypeptide quantitation.

The Edman Sequencing Research Group (ESRG) designs studies on the use of Edman degradation for protein and peptide analysis. These studies provide a means for participating laboratories to compare their analyses against a benchmark of those from other laboratories that provide this valuable service. The main purpose of the 2006 study was to determine how accurate Edman sequencing is for quantitative analysis of polypeptides. Secondarily, participants were asked to identify a modified amino acid residue, N-epsilon-acetyl lysine [Lys(Ac)], present within one of the peptides. The ESRG 2006 peptide mixture consisted of three synthetic peptides. The Peptide Standards Research Group (PSRG) provided two peptides, with the following sequences: KAQYARSVLLEKDAEPDILELATGYR (peptide B), and RQAKVLLYSGR (peptide C). The third peptide, peptide C*, synthesized and characterized by ESRG, was identical to peptide C but with acetyl lysine in position 4. The mixture consisted of 20% peptide B and 40% each of peptide C and its acetylated form, peptide C*. Participating laboratories were provided with two tubes, each containing 100 picomoles of the peptide mixture (as determined by quantitative amino acid analysis) and were asked to provide amino acid assignments, peak areas, retention times at each cycle, as well as initial and repetitive yield estimates for each peptide in the mixture. Details about instruments and parameters used in the analysis were also collected. Participants in the study with access to a mass spectrometer (MALDI-TOF or ESI) were asked to provide information about the relative peak areas of the peptides in the mixture as a comparison with the peptide quantitation results from Edman sequencing. Positive amino acid assignments were 88% correct for peptide C and 93% correct for peptide B. The absolute initial sequencing yields were an average of 67% for peptide (C+C*) and 65.6 % for peptide B. The relative molar ratios determined by Edman sequencing were an average of 4.27 (expected ratio of 4) for peptides (C+C*)/B, and 1.49 for peptide C*/C (expected ratio of 1); the seemingly high 49% error in quantification of Lys(Ac) in peptide C* can be attributed to commercial unavailability of its PTH standard. These values compare very favorably with the values obtained by mass spectrometry.

Structure and function of mutationally generated monomers of dimeric phosphoribosylanthranilate isomerase from Thermotoga maritima.

BACKGROUND: Oligomeric proteins may have been selected for in hyperthermophiles because subunit association provides extra stabilization. Phosphoribosylanthranilate isomerase (PRAI) is monomeric and labile in most mesophilic microorganisms, but dimeric and stable in the hyperthermophile Thermotoga maritima (tPRAI). The two subunits of tPRAI are associated back-to-back and are locked together by a hydrophobic loop. The hypothesis that dimerization is important for thermostability has been tested by rationally designing monomeric variants of tPRAI. RESULTS: The comparison of tPRAI and PRAI from Escherichia coli (ePRAI) suggested that levelling the nonplanar dimer interface would weaken the association. The deletion of two residues in the loop loosened the dimer. Subsequent filling of the adjacent pocket and the exchange of polar for apolar residues yielded a weakly associating and a nonassociating monomeric variant. Both variants are as active as the parental dimer but far more thermolabile. The thermostability of the weakly associating monomer increased significantly with increasing protein concentration. The X-ray structure of the nonassociating monomer differed from that of the parental subunit only in the restructured interface. The orientation of the original subunits was maintained in a crystal contact between two monomers. CONCLUSIONS: tPRAI is dimeric for reasons of stability. The clearly separated responsibilities of the betaalpha loops, which are involved in activity, and the alphabeta loops, which are involved in protein stability, has permitted the evolution of dimers without compromising their activity. The preserved interaction in the crystal contacts suggests the most likely model for dimer evolution.

[What is the value of pain therapy in the German refined diagnosis-related-groups system?]. / Was ist Schmerztherapie im "German refined--diagnosis related groups-System" wert?

The German refined diagnosis-related-groups (G-DRG) system was introduced on 1st January 2003, initially on a voluntary basis and on 1st January 2004 the use of a G-DRG costing for stationary hospital treatment became obligatory. The possibility of a description of acute and chronic pain therapy in the G-DRG system was initially rudimentary and not logically planned and also a fair allotment of proceeds according to resources was not possible. By further development of the G-DRG system, pain therapeutic treatment could be improved in some areas, but in others it still remains unsatisfactory. This article offers a summary of the underlying systematics of the G-DRG system and consideration of chronic and current pain therapy in the G-DRG system 2006. In addition to information on currently available possibilities of a pain therapeutical coding in conformation with the G-DRG system, the tasks which are still outstanding will be outlined.