Contactin-associated protein 2 autoantibodies can be associated with multifocal motor-like neuropathy: a case report

Autoantibodies against contactin-associated protein 2 (CASPR2) are usually associated with autoimmune encephalitis and neuromyotonia. Their association with inflammatory neuropathies has been described in case reports albeit all with distal symmetric manifestation. Here, we report a patient who developed distal arm paresis, dominantly of the right arm, over the course of 1 year. Electroneurography showed a conduction block of motor nerve conduction, nerve ultrasonography a swelling of the right median and ulnar nerve and flow cytometry an increase in natural killer (NK cells) in the blood and natural killer T (NKT) cells in the cerebrospinal fluid (CSF), therefore indicating a multifocal motor neuropathy-like (MMN-like) phenotype. CASPR2 autoantibodies were detected in serum and CSF. Through immunotherapy with intravenous immunoglobulins the patient showed clinical and neurographic improvement. We therefore describe the first association of CASPR2 autoantibodies with a MMN-like clinical manifestation, extending the spectrum of CASPR2-associated diseases.

Active impedance matching of a cryogenic radio frequency resonator for ion traps

A combination of direct current (DC) fields and high amplitude radio frequency (RF) fields is necessary to trap ions in a Paul trap. Such high electric RF fields are usually reached with the help of a resonator in close proximity to the ion trap. Ion trap based quantum computers profit from good vacuum conditions and low heating rates that cryogenic environments provide. However, an impedance matching network between the resonator and its RF source is necessary, as an unmatched resonator would require higher input power due to power reflection. The reflected power would not contribute to the RF trapping potential, and the losses in the cable induce additional heat into the system. The electrical properties of the matching network components change during cooling, and a cryogenic setup usually prohibits physical access to integrated components while the experiment is running. This circumstance leads to either several cooling cycles to improve the matching at cryogenic temperatures or the operation of poorly matched resonators. In this work, we demonstrate an RF resonator that is actively matched to the wave impedance of coaxial cables and the signal source. The active part of the matching circuit consists of a varactor diode array. Its capacitance depends on the DC voltage applied from outside the cryostat. We present measurements of the power reflection, the Q-factor, and higher harmonic signals resulting from the nonlinearity of the varactor diodes. The RF resonator is tested in a cryostat at room temperature and cryogenic temperatures, down to 4.3 K. A superior impedance matching for different ion traps can be achieved with this type of resonator.

[de novo hATTR amyloidosis after domino transplantation of a donor's liver: a case report for the use of Patisiran]

Hereditary transthyretin-mediated (hATTR) amyloidosis is a rare, rapidly progressing, and potentially life-threatening disease caused by one of more than 120 mutations in the transthyretin (TTR) gene. As a result of the cumulative amyloid deposits, especially in the peripheral nerves and the heart, the majority of patients develop progressive, peripheral sensorimotor polyneuropathy and biventricular cardiomyopathy over time.Since TTR - and its amyloidogenic variants too - is predominantly synthesized in the liver, early, orthotopic liver transplantation (LTx) is a treatment option that can be used to potentially stop the progression of hATTR amyloidosis.The actual case shows a patient with hepatocellular carcinoma who received the organ of a patient with hATTR as part of a domino liver transplantation. After approximately 10 years, the patient started to develop the characteristic symptoms of the metabolic disorder. Because of a further progression of the amyloidosis, therapy with the RNA interference therapeutic patisiran was initiated, which temporarily halted the progression.

[Gene therapy options for hereditary transthyretin-related amyloidosis]

Hereditary transthyretin-related amyloidosis (ATTRv) is a rare autosomal dominant disease and is fatal if left untreated. It is caused by mutations in the transthyretin gene. All known mutations induce misfolding of the tetrameric transthyretin molecule and protein deposits in multiple organs. In peripheral nerves this result in sensorimotor and autonomic polyneuropathy and in cardiac muscle it causes cardiomyopathy. Untreated ATTRv is characterized by an irreversible and progressive course and death 7-11 years after symptom onset. Treatment options consist of TTR stabilizing drugs, such as tafamidis and active agents that selectively interfere at the mRNA level, the so-called gene silencers patisiran and inotersen. All forms of treatment aim to prevent amyloid tissue deposition in tissues and organ dysfunction. Patisiran works by RNA interference on endogenous mechanisms of gene expression. It results in the cleavage of TTR-mRNA using the cytoplasmatic RNA-induced silencing complex. Inotersen, an antisense oligonucleotide, degrades TTR-mRNA via activation of nuclear RNase H. Both mechanisms result in a significant reduction of TTR protein serum levels. The efficacy could be demonstrated by slowing or improving neuropathy progression in the phase III study APOLLO (patisiran) or the NEURO-TTR study (inotersen). Furthermore, the use of both agents led to an improvement in the quality of life in patients with ATTRv. Both forms of treatment are approved in Germany since August 2018 for polyneuropathy stages 1 and 2 according to Coutinho. The choice of treatment should be carried out individually considering drug formulation, contraindications and the necessary safety monitoring controls.

THz microscope for three-dimensional imaging with superconducting Josephson junctions

Superconducting Josephson junctions have a wide range of applications ranging from quantum computing to voltage standards, and they may also be employed as versatile sensors for high-frequency radiation and magnetic fields. In this work, we present a unique measurement setup utilizing a single Josephson junction on a cantilever for high-resolution spatial measurements of spectroscopically resolved THz and microwave field distributions. This THz microscope can be utilized to measure power and frequency of electromagnetic radiation from ∼1 GHz to 5 THz. It may also be used to measure static magnetic fields and provide topological scans of samples. The samples can be both actively radiating or passively irradiated at either room temperature or cryogenic temperatures. We review the measurement setup of the THz microscope and describe the evaluation of its measurement data to achieve three-dimensional visualizations of the field distributions. The diverse capabilities of this unique tool are demonstrated by its different measurement modes with measurements of field distributions at 20 GHz and 1.4 THz, spectroscopically resolved THz measurements, and magnetic field measurements.

Genome silencer therapy leading to 'regression' of cardiac amyloid load on cardiovascular magnetic resonance: a case report

BACKGROUND

Hereditary or variant transthyretin amyloidosis (ATTRv) is a progressive disease manifesting with neuropathy and/or cardiomyopathy. An early and accurate diagnosis of cardiac amyloidosis is a pre-requisite for timely and appropriate patient management, including anti-amyloid therapies, as it is associated with heart failure, conduction disease, and arrhythmias, leading to reduced quality of life and early death.

CASE SUMMARY

We present the case of an ATTRv male patient presenting with a mixed amyloidosis phenotype (neuropathy and cardiomyopathy). Cardiac disease manifestation comprised tachyarrhythmias (atrial fibrillation) and conduction abnormalities (atrio-ventricular block) in addition to segmental left ventricular (LV) hypertrophy (septal wall) due to regionally pronounced amyloid deposits in the basal LV myocardium. Interestingly, by means of serial cardiovascular magnetic resonance (CMR) studies, we were able to demonstrate an impressive and unexpected improvement of cardiomyopathy findings within a relatively short period-of-time after the implementation of genome-silencer therapies.

DISCUSSION

This is our second case report that showed ATTRv cardiomyopathy reversal under anti-amyloid therapy-documented by multi-parametric CMR. Our findings support the hypothesis that amyloid infiltration leading to cardiomyopathy is not an irreversible pathological process-but rather a dynamic one, that cannot only be stopped but even reversed (to a certain degree) by currently emerging anti-amyloid therapies. Moreover, the role of serial multi-parametric CMR imaging for surveillance of cardiomyopathy dynamics under these therapies is nicely illustrated.

Ergebnisse der 14. Erhebung der Deutschen Gesellschaft für Neurologie zur Struktur der Neurologischen Kliniken mit Akutversorgungsauftrag in Deutschland

Die Kommission 1.4 Anhaltszahlen und Qualitätssicherung der Deutschen Gesellschaft für Neurologie führt alle 2 Jahre eine Umfrage unter den an der Akutversorgung neurologischer Patienten teilnehmenden neurologischen Kliniken in Deutschland durch. Anhaltszahlen zur akutneurologischen Versorgung in Deutschland, der Infrastruktur der Krankenhäuser und der neurologischen Fachabteilungen aus dem Jahr 2019 wurden 2020 erfragt und mit den Ergebnissen der Vorumfragen verglichen.

Bei hoher Antwortquote von 67 % gehörte zu den wesentlichen Ergebnissen, dass die Größe der Kliniken und deren Ertragsstärke seit 2015 weitgehend stagnieren. Dies korreliert zeitlich mit dem seit 2015 anhaltenden, die Versorgung einschränkenden Pflegepersonalmangel und dem im Vergleich zu 2017 leicht gemilderten Ärztemangel. Der Ärztemangel konnte durch Rekrutierung von Ärzten aus dem Ausland abgemildert werden. Mindestens einen Arzt mit einem Examen von außerhalb der Europäischen Union beschäftigten 71 % der Kliniken. Nur eine Minderheit bietet spezielle Fortbildungsangebote für aus dem Ausland rekrutierte Ärzte an. Ambulante Strukturen wurden weiter ausgebaut.

Zur Thrombektomie müssen Patienten von 1/3 der Kliniken verlegt werden und mehr als 50 km Transportweg überwinden. Im Vergleich zu 2017 erfolgen zumindest zeitweise Thrombektomien in insgesamt deutlich mehr Kliniken. Allerdings führten 48 Kliniken durchschnittlich weniger als 1 Thrombektomie/Woche durch.

Obwohl etwa 1/3 der Krankenhäuser, aus denen Antworten eingingen, sog. Kalkulationshäuser sind, erhielt nur die Hälfte der neurologischen Fachabteilungen an diesen Häusern differenzierte Rückmeldungen zur Kostenstruktur.

Die Anhaltszahlenumfrage zum Jahr 2019 zeigt schlaglichtartig Problemfelder neurologischer Kliniken in Deutschland auf, die aktuell durch die Pandemielage überdeckt sein mögen, aber bereits jetzt als Herausforderungen für die Rückkehr zur Normalität identifiziert werden können.

Detecting myasthenia gravis as a cause of unclear dysphagia with an endoscopic tensilon test

Aims:

The flexible endoscopic evaluation of swallowing-tensilon test (FTT) was developed to diagnose myasthenia gravis (MG) in patients with unclear pharyngeal dysphagia. The purpose of this study was to determine sensitivity and specificity of the FTT and compare its diagnostic validity with that of other diagnostic markers.

Methods:

In this single-centre pragmatic clinical cohort study, a total of 100 patients with unclear pharyngeal dysphagia were eligible to undergo FTT. All patients were subjected to FTT and subsequently followed up clinically. FTT was considered positive if a significant improvement of pharyngeal swallowing function could be objectified endoscopically upon administration of edrophonium chloride. In addition, repetitive nerve stimulation test and serum MG antibody analysis were conducted.

Results:

All subjects (mean age 62.5 ± 14.1 years, female 33) underwent FTT without any complications. According to the results of the diagnostic procedures and based on long-term clinical follow-up for at least 3 years, 51 patients were finally diagnosed with MG. The sensitivity and specificity for the FTT was 88.2% and 95.9%, respectively. Application of the Cochran’s Q test showed statistically significant heterogeneity among the diagnostic tests, with results indicating FTT performance to be more accurate than the repetitive nerve stimulation results (p < 0.001) and comparable with serum antibody tests (p > 0.99).

Conclusion:

FTT has excellent clinical properties to be used routinely in the assessment of dysphagia with isolated or predominant pharyngeal muscle involvement allowing rapid and accurate diagnosis of MG.

Quality of life outcomes in APOLLO, the phase 3 trial of the RNAi therapeutic patisiran in patients with hereditary transthyretin-mediated amyloidosis

Introduction: Hereditary transthyretin-mediated (hATTR) amyloidosis is a rare, fatal, multisystem disease leading to deteriorating quality of life (QOL). The impact of patisiran on QOL in patients with hATTR amyloidosis with polyneuropathy from the phase 3 APOLLO study (NCT01960348) is evaluated.Methods: Patients received either patisiran 0.3 mg/kg (n = 148) or placebo (n = 77) intravenously once every three weeks for 18 months. Multiple measures were used to assess varying aspects of QOL.Results: At 18 months, compared with placebo, patisiran improved Norfolk Quality of Life-Diabetic Neuropathy (Norfolk QOL-DN) score; (least squares [LS] mean difference: -21.1; p = 1.10 × 10^-10; improved across all domains), EuroQoL 5-dimensions 5-levels (LS mean difference: 0.2; p = 1.4 × 10^-12), EuroQoL-visual analog scale (LS mean difference: 9.5; p=.0004), Rasch-built Overall Disability Scale (LS mean difference: 9.0; p = 4.07 × 10^-16) and Composite Autonomic Symptom Score-31(COMPASS-31; LS mean difference: -7.5; p=.0008). Placebo-treated patients experienced rapid QOL deterioration; treatment effects for patisiran were observed as early as 9 months. At 18 months, patisiran improved Norfolk QOL-DN total score and three individual domains as well as COMPASS-31 total scores relative to baseline. Consistent benefits were also observed in the cardiac subpopulation.Conclusion: The benefits of patisiran across all QOL measures and the rapid deterioration observed with placebo, highlight the urgency in early treatment for patients with hATTR amyloidosis with polyneuropathy.

Chance or challenge, spoilt for choice? New recommendations on diagnostic and therapeutic considerations in hereditary transthyretin amyloidosis with polyneuropathy: the German/Austrian position and review of the literature

Hereditary transthyretin amyloidosis is caused by pathogenic variants (ATTR_v) in the TTR gene. Alongside cardiac dysfunction, the disease typically manifests with a severely progressive sensorimotor and autonomic polyneuropathy. Three different drugs, tafamidis, patisiran, and inotersen, are approved in several countries, including the European Union and the United States of America. By stabilizing the TTR protein or degrading its mRNA, all types of treatment aim at preventing amyloid deposition and stopping the otherwise fatal course. Therefore, it is of utmost importance to recognize both onset and progression of neuropathy as early as possible. To establish recommendations for diagnostic and therapeutic procedures in the follow-up of both pre-symptomatic mutation carriers and patients with manifest ATTR_v amyloidosis with polyneuropathy, German and Austrian experts elaborated a harmonized position. This paper is further based on a systematic review of the literature. Potential challenges in the early recognition of disease onset and progression are the clinical heterogeneity and the subjectivity of sensory and autonomic symptoms. Progression cannot be defined by a single test or score alone but has to be evaluated considering various disease aspects and their dynamics over time. The first-line therapy should be chosen based on individual symptom constellations and contra-indications. If symptoms worsen, this should promptly implicate to consider optimizing treatment. Due to the rareness and variability of ATTR_v amyloidosis, the clinical course is most importantly directive in doubtful cases. Therefore, a systematic follow-up at an experienced center is crucial to identify progression and reassure patients and carriers.

Sphenopalatine Ganglion Stimulation to Augment Cerebral Blood Flow

Background and Purpose—

Many patients with acute ischemic stroke are not eligible for thrombolysis or mechanical reperfusion therapies due to contraindications, inaccessible vascular occlusions, late presentation, or large infarct core. Sphenopalatine ganglion (SPG) stimulation to enhance collateral flow and stabilize the blood-brain barrier offers an alternative, potentially more widely deliverable, therapy.

Methods—

In a randomized, sham-controlled, double-masked trial at 41 centers in 7 countries, patients with anterior circulation ischemic stroke not treated with reperfusion therapies within 24 hours of onset were randomly allocated to active SPG stimulation or sham control. The primary efficacy outcome was improvement beyond expectations on the modified Rankin Scale of global disability at 90 days (sliding dichotomy), assessed in the modified intention-to-treat population. The initial planned sample size was 660 patients, but the trial was stopped early when technical improvements in device placement occurred, so that analysis of accumulated experience could be conducted to inform a successor trial.

Results—

Among 303 enrolled patients, 253 received at least one active SPG or sham stimulation, constituting the modified intention-to-treat population (153 SPG stimulation and 100 sham control). Age was median 73 years (interquartile range, 64–79), 52.6% were female, deficit severity on the National Institutes of Health Stroke Scale was median 11 (interquartile range, 9–15), and time from last known well median 18.6 hours (interquartile range, 14.5–22.5). For the primary outcome, improved 3-month disability beyond expectations, rates in the SPG versus sham treatment groups were 49.7% versus 40.0%; odds ratio, 1.48 (95% CI, 0.89–2.47); P =0.13. A significant treatment interaction with stroke location (cortical versus noncortical) was noted, P =0.04. In the 87 patients with confirmed cortical involvement, rates of improvement beyond expectations were 50.0% versus 27.0%; odds ratio, 2.70 (95% CI, 1.08–6.73); P =0.03. Similar response patterns were observed for all prespecified secondary efficacy outcomes. No differences in mortality or serious adverse event safety end points were observed.

Conclusions—

SPG stimulation within 24 hours of onset is safe in acute ischemic stroke. SPG stimulation was not shown to statistically significantly improve 3-month disability above expectations, though favorable outcomes were nominally higher with SPG stimulation. Beneficial effects may distinctively be conferred in patients with confirmed cortical involvement. The results of this study need to be confirmed in a larger pivotal study.

Clinical Trial Registration—

URL: https://www.clinicaltrials.gov . Unique identifier: NCT03767192.

MnSi nanostructures obtained from epitaxially grown thin films: magnetotransport and Hall effect

We present a comparative study of the (magneto)transport properties, including Hall effect, of bulk, epitaxially grown thin film and nanostructured MnSi. In order to set our results in relation to published data we extensively characterize our materials, this way establishing a comparatively good sample quality. Our analysis reveals that in particular for thin film and nanostructured material, there are extrinsic and intrinsic contributions to the electronic transport properties, which by modeling the data we separate out. Finally, we discuss our Hall effect data of nanostructured MnSi under consideration of the extrinsic contributions and with respect to the question of the detection of a topological Hall effect in a skyrmionic lattice.

[Transthyretin Familial Amyloid Polyneuropathy - Disease Profile of a Multisystem Disorder]

Transthyretin-related Familial Amyloid Polyneuropathy (ATTR Amyloidosis, former FAP, here called TTR-FAP) is a rare, progressive autosomal dominant inherited amyloid disease ending fatal within 5 - 15 years after final diagnosis. TTR-FAP is caused by mutations of transthyretin (TTR), which forms amyloid fibrils affecting peripheral and autonomic nerves, the heart and other organs. Due to the phenotypic heterogeneity and partly not specific enough clinical symptoms, diagnosis of TTR-FAP can be complicated. False diagnoses can include idiopathic polyneuropathy, chronic inflammatory demyelinating polyneuropathy, diabetic neuropathy as well as paraneoplastic syndrome. Hence, it is assumed that many cases remain unreported. Early and correct diagnosis of TTR-FAP is crucial, since appropriate therapeutic options exist. TTR-FAP should always be differentially diagnosed, when apart from a progressive peripheral polyneuropathy, additional symptoms as autonomic dysfunction, cardiomyopathy, gastrointestinal disorders, unexpected loss of weight, carpal tunnel syndrome, restrictions of renal function, epileptic fits, and corneal and vitreous body clouding occur. Histological evidence of amyloid and successive immunohistochemical evidence of transthyretin as well as genetic testing for transthyretin mutations, lead to an accurate diagnosis.

Modelling plexcitons of periodic gold nanorod arrays with molecular components

Plasmonic or exciton/plasmon (plexcitonic) systems are presently described based on electromagnetic models, ignoring the need for an improved microscopic understanding. This is based on the fact that a full quantum mechanical approach on a micrometer scale still represents a considerable challenge. In this paper we report on the experimental observation of plexcitons in 2D gold nanorod array systems coupled to dye molecules and we provide a description of the experimental data using a quantum model. We show that treating the collective behavior in the array as being represented by a single quasiparticle is a suitable approximation that offers the opportunity to avoid the complicated calculation of long-distance interactions between the individual nanoparticles of the plexcitonic, periodic system. This enables us to model the optical response of plasmons in nanostructured arrays in contact with quantum emitters and to derive microscopic informations. Our work provides a potential tool for the design of plexcitonic devices, which rely on periodic metallic nanostructures.

Measurement system for temperature dependent noise characterization of magnetoresistive sensors

Magnetoresistive (MR) sensors and sensor systems are used in a large variety of applications in the field of industrial automation, automotive business, aeronautic industries, and instrumentation. Different MR sensor technologies like anisotropic magnetoresistive, giant magnetoresistive, and tunnel magnetoresistive sensors show strongly varying properties in terms of magnetoresistive effect, response to magnetic fields, achievable element miniaturization, manufacturing effort, and signal-to-noise ratio. Very few data have been reported so far on the comparison of noise performance for different sensor models and technologies, especially including the temperature dependence of their characteristics. In this paper, a stand-alone measurement setup is presented that allows a comprehensive characterization of MR sensors including sensitivity and noise over a wide range of temperatures.

Preventable and potentially preventable deaths in severely injured patients: a retrospective analysis including patterns of errors

PURPOSE

Analyzing preventable and potentially preventable deaths is a well-known procedure for improving trauma care. This study analyzes preventable and potentially preventable deaths in German trauma patients.

METHODS

Patients aged between 16 and 75 years with an Injury Severity Score >15 who were primary admitted from July 2002 to December 2011 were analyzed in this study. Data from the patients' hospital records were retrospectively analyzed, and cases were categorized as preventable, potentially preventable, and non-preventable deaths. In addition, trauma management was screened for errors.

RESULTS

2304 patients were admitted from July 2002 to December 2011. 763 of which fulfilled the defined criteria. The mortality rate was 25.3 %. Eight cases (4.2 %) were declared as preventable deaths and 31 cases (16.1 %) as potentially preventable deaths. The most common errors in preclinical trauma care related to airway management. The main clinical error was insufficient hemorrhage control. Fluid overload from infusion was the second most common fault in both.

CONCLUSIONS

Preventable and potentially preventable errors still occur in the treatment of severely injured patients. Errors in hemorrhage control and airway management are the most common human treatment errors. The knowledge of these errors could help to improve trauma care in the future.

Combining Growth Factor and Bone Marrow Cell Therapy Induces Bleeding and Alters Immune Response After Stroke in Mice

BACKGROUND AND PURPOSE

Bone marrow cell (BMC)-based therapies, either the transplantation of exogenous cells or stimulation of endogenous cells by growth factors like the granulocyte colony-stimulating factor (G-CSF), are considered a promising means of treating stroke. In contrast to large preclinical evidence, however, a recent clinical stroke trial on G-CSF was neutral. We, therefore, aimed to investigate possible synergistic effects of co-administration of G-CSF and BMCs after experimental stroke in mice to enhance the efficacy compared with single treatments.

METHODS

We used an animal model for experimental stroke as paradigm to study possible synergistic effects of co-administration of G-CSF and BMCs on the functional outcome and the pathophysiological mechanism.

RESULTS

G-CSF treatment alone led to an improved functional outcome, a reduced infarct volume, increased blood vessel stabilization, and decreased overall inflammation. Surprisingly, the combination of G-CSF and BMCs abrogated G-CSFs' beneficial effects and resulted in increased hemorrhagic infarct transformation, altered blood-brain barrier, excessive astrogliosis, and altered immune cell polarization. These increased rates of infarct bleeding were mainly mediated by elevated matrix metalloproteinase-9-mediated blood-brain barrier breakdown in G-CSF- and BMCs-treated animals combined with an increased number of dilated and thus likely more fragile vessels in the subacute phase after cerebral ischemia.

CONCLUSIONS

Our results provide new insights into both BMC-based therapies and immune cell biology and help to understand potential adverse and unexpected side effects.

Case report of bilateral relapsing-remitting sciatic nerve palsy during two pregnancies

BACKGROUND

Unlike puerperal peripheral nerve lesions, mononeuropathy during pregnancy is rarely encountered. We report a case of bilateral relapsing-remitting sciatic nerve palsy during two pregnancies. An extensive literature search in PubMed brought no similar cases.

CASE PRESENTATION

A healthy young woman presented with initially unilateral sciatic nerve palsy, which manifested and worsened during the early phases of two successive pregnancies. Electrophysiology revealed axonal lesion of the sciatic nerve with predominant affection of the peroneal part. Extensive laboratory examination including cerebrospinal fluid examination was unremarkable. MR imaging was compatible with bilateral intraneural perineurioma. Recurrent occurrence during two pregnancies and an anamnestic relationship between intermediate worsening of the paresis and the menstrual cycle suggested hormone-dependency of the tumor. However, response to repeated intravenous immunoglobuline (IVIG) therapy during pregnancy and shortly after childbirth resulted in partial reversion of foot drop. This was also indicative of an immunoneuropathy. Nerve biopsy was not performed because of clinical improvement. The precise underlying neuropathological mechanism remained unclear.

CONCLUSION

To increase knowledge and awareness of this rare entity, potential etiologies of mononeuropathies during pregnancy are discussed in the context of this case report. In the rare occasion of peripheral nerve mononeuropathy during pregnancy, in which therapeutic opportunities are limited, IVIG therapy may be an option when the etiology cannot clearly be determined after thorough medical investigation.

Data2Dynamics: a modeling environment tailored to parameter estimation in dynamical systems

Modeling of dynamical systems using ordinary differential equations is a popular approach in the field of systems biology. Two of the most critical steps in this approach are to construct dynamical models of biochemical reaction networks for large datasets and complex experimental conditions and to perform efficient and reliable parameter estimation for model fitting. We present a modeling environment for MATLAB that pioneers these challenges. The numerically expensive parts of the calculations such as the solving of the differential equations and of the associated sensitivity system are parallelized and automatically compiled into efficient C code. A variety of parameter estimation algorithms as well as frequentist and Bayesian methods for uncertainty analysis have been implemented and used on a range of applications that lead to publications.

AVAILABILITY AND IMPLEMENTATION

The Data2Dynamics modeling environment is MATLAB based, open source and freely available at http://www.data2dynamics.org.

CONTACT

andreas.raue@fdm.uni-freiburg.de

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Drive-field Frequency Dependent MPI Performance of Single-Core Magnetite Nanoparticle Tracers

The drive-field frequency of Magnetic Particle Imaging (MPI) systems plays an important role for system design, safety requirements and tracer selection. Because the commonly utilized MPI drive-field frequency of 25 kHz might be increased in future system generations to avoid peripheral nerve stimulation, a performance evaluation of tracers at higher frequencies is desirable. We have studied single-core magnetite nanoparticles that were optimized for MPI applications, utilizing Magnetic Particle Spectrometers (MPS) with drive-field frequencies in the range from 1 kHz up to 100 kHz. The particles have core diameters of 25 nm and a hydrodynamic size of 77 nm. Measurements in the frequency range above 5 kHz were carried out with a newly designed MPS system. In addition, to exclude possible particle interaction, samples of different concentrations were characterized and compared.

Vitamin B status in patients with type 2 diabetes mellitus with and without incipient nephropathy

AIM

To investigate the vitamin B status, with particular focus on vitamin B6, in adults with and without incipient nephropathy secondary to type 2 diabetes mellitus.

METHODS

Plasma and/or urine concentrations of vitamins B₆, B₁, B₁₂, related vitamers and biomarkers (including total homocysteine, methylmalonic acid) were measured in 120 adults with type 2 diabetes (including 46 patients with microalbuminuria) and 52 non-diabetic control subjects.

RESULTS

Plasma concentrations of pyridoxal 5'-phosphate (PLP) were significantly lower in patients with type 2 diabetes than in control subjects (median: 22.7 nmol/L, diabetes with microalbuminuria; 26.8 nmol/L, diabetes without microalbuminuria; 39.5 nmol/L, non-diabetic control; p<0.0001). The prevalence of low PLP (<30 nmol/L) was 63%, 58%, and 25% in the diabetes groups with and without microalbuminuria and the control group, respectively. Plasma levels of pyridoxine and pyridoxal were also lower (p<0.0001), but levels of pyridoxamine, pyridoxamine 5'-phosphate, and pyridoxic acid were higher in both groups with diabetes compared to the control group (p<0.001). Thiamine deficiency was highly prevalent in all groups, whereas low vitamin B₁₂ and elevated methylmalonic acid were rare. Increased levels of C-reactive protein and soluble vascular cell adhesion molecule-1 were observed in the groups with diabetes (p<0.05, versus healthy control).

CONCLUSIONS

Deficiency of vitamin B₆ (PLP, pyridoxine, pyridoxal) and vitamin B₁ (thiamine) was prevalent in type 2 diabetes. Incipient nephropathy was associated with more pronounced alterations in vitamin B₆ metabolism and stronger indications of endothelial dysfunction and inflammation.

Feasibility platform for stroke studies: an online tool to improve eligibility criteria for clinical trials

BACKGROUND AND PURPOSE

Eligibility criteria are a key factor for the feasibility and validity of clinical trials. We aimed to develop an online tool to assess the potential effect of inclusion and exclusion criteria on the proportion of patients eligible for an acute stroke trial.

METHODS

We identified relevant inclusion and exclusion criteria of acute stroke trials. Based on these criteria and using a cohort of 1537 consecutive patients with acute ischemic stroke from 3 stroke centers, we developed a web portal feasibility platform for stroke studies (FePASS) to estimate proportions of eligible patients for acute stroke trials. We applied the FePASS resource to calculate the proportion of patients eligible for 4 recent stroke studies.

RESULTS

Sixty-one eligibility criteria were derived from 30 trials on acute ischemic stroke. FePASS, publicly available at http://fepass.uni-muenster.de, displays the proportion of patients in percent to assess the effect of varying values of relevant eligibility criteria, for example, age, symptom onset time, National Institutes of Health Stroke Scale, and prestroke modified Rankin Scale, on this proportion. The proportion of eligible patients for 4 recent stroke studies ranged from 2.1% to 11.3%. Slight variations of the inclusion criteria could substantially increase the proportion of eligible patients.

CONCLUSIONS

FePASS is an open access online resource to assess the effect of inclusion and exclusion criteria on the proportion of eligible patients for a stroke trial. FePASS can help to design stroke studies, optimize eligibility criteria, and to estimate the potential recruitment rate.

Analysis of early phase and subsequent phase III stroke studies of neuroprotectants: outcomes and predictors for success

Background

Efficacy of neuroprotective treatments for ischemic stroke was not convincingly demonstrated in clinical phase III trials so far, whereas some preceding early phase studies found neuroprotection to be beneficial. We aimed to determine the frequency with which phase III studies are preceded by positive early phase studies, and to identify characteristics of early phase studies that are associated with correct prediction of phase III studies.

Methods

We identified phase III studies and corresponding early phase studies of neuroprotective treatments for stroke. Data on study characteristics of early phase trials were extracted and compared between studies that were classified according to their results as “false positive” and “true neutral” using logistic regression analysis.

Results

Forty-six phase III studies and 59 corresponding early phase studies were identified. Only one phase III study was positive and this study was followed by a larger negative study. Twenty-two (37.3%) early phase studies were considered to be false positive and 37 (62.7%) to be true neutral. None of the early phase study characteristics were significantly associated with correct prediction of phase III studies.

Conclusions

More than one third of early phase studies on neuroprotective stroke treatments are false positive. Neither the results nor specific study design characteristics of early phase stroke studies reliably predict success in phase III trials. Further efforts are needed to improve early phase studies regarding its predictability and to identify those early studies that should be advanced to phase III trials.

[TraumaNetwork, Trauma Registry of the DGU®, Whitebook, S3 Guideline on Treatment of Polytrauma/Severe Injuries - An Approach for Validation by a Retrospective Analysis of 2304 Patients (2002-2011) of a Level 1 Trauma Centre]

Background: In the last decades, a reduction in mortality in severely injured patients with an ISS ≥ 16 could be observed. Some authors report a death rate of about 22 %. Moreover, there were some new insights in the last years such as the reduction in mortality by use of whole-body CT and the introduction of the S3 guideline of the German Society of Trauma Surgery "Treatment of Patients with Severe and Multiple Injuries" have supported the evidence-based treatment of severely injured patients. Methods: A retrospective analysis of 2304 patients was performed between 2002 and 2011. The data of the authors' clinic for the trauma registry of the DGU® were used. After applying the inclusion criteria, ISS ≥ 16 and primary transfer from the accident site, 968 patients remained. Results: In the study population, a mean ISS of 29.81 and a mean GCS of 9.42 were found. The average age was 46.04 years. The mortality rate was 28.7 %. A significant difference between decedents and survivors was found at the ISS, GCS, RTS, new ISS, TRISS, RISC, AIS head, AIS skin, RR pre-clinical, pre-clinical heart rate and age. To test whether the lethality was reduced by the increased use of whole-body CT, a division into a group prior to and from 2009 was performed. Results revealed a significant increase in the whole-body CT rate from 56.96 to 71.7 %. The mortality rate declined from 32.3 to 24.5 %. In the same way it was verified whether the S3 guideline had an impact on mortality. Therefore, a division into groups before and from 2011 was conducted. Here, the mortality rate decreased from 30.4 to 18.4 %. In addition, a comparison between 2010 and 2011 was performed. Overall, there were statistically significant differences in the trauma room time, the surgical time, the volume infused, the rate of multiple organ failure and the rate of whole-body CTs performed. Conclusion: In the period from 2002 to 2011 a mortality rate of 28.7 % was found. The higher rate in comparison to published data is most likely explained by the high rate of serious and severe head injuries. The increased use of whole-body CT and the introduction of the S3 guideline led to a significant decrease in mortality in the authors' patient population. This is due particularly to the accelerating of the treatment of severely injured patients, the reduction of the infused volume, shortened surgical phase within the first 24 hours and the increased use of whole-body CT.

Bone marrow-derived mononuclear cells do not exert acute neuroprotection after stroke in spontaneously hypertensive rats

Bone marrow-derived mononuclear cells (BM-MNCs) were shown to improve the outcome in animal stroke models and clinical pilot studies on BM-MNCs for stroke patients were already conducted. However, relevant aspects of pre-clinical evaluation, such as the use of animals with comorbidities and dose-response studies, were not thoroughly addressed so far. We therefore investigated different BM-MNC doses in the clinical meaningful stroke model of spontaneously hypertensive (SH) rats. Three hours after the onset of transient middle cerebral artery occlusion (MCAO) animals received either one of three syngeneic BM-MNC doses or placebo intravenously. The primary endpoint was the infarct size. Secondary endpoints included functional outcome, mortality, inflammatory processes, and the dose-response relationship. In contrast to previous studies which used healthy animals no beneficial effect of BM-MNCs was found. Infarct volumes, mortality, behavioral outcomes, and the extent of the inflammatory response to cerebral ischemia were comparable in all groups. In conclusion, we could not demonstrate that early BM-MNC treatment improves the outcome after stroke in SH rats. Whether BM-MNCs improve neurological recovery after delayed treatment initiation was not investigated in the present study, but our data indicates that this should be determined in co-morbid animal stroke models before moving to large-scale clinical studies. Future preclinical stroke studies on co-morbid animals should also include groups of healthy animals in order to determine whether negative results can be attributed to the comorbid condition.

Cortical photothrombotic infarcts impair the recall of previously acquired memories but spare the formation of new ones

BACKGROUND AND PURPOSE

Despite a high incidence of poststroke dementia, there is no specific treatment for this condition. Because the evaluation of poststroke cognitive deficits in animal models of stroke is exceedingly challenging, the preclinical evaluation of candidate drugs is limited. We aimed to explore the impact of small cortical photothrombotic strokes on poststroke cognition, thereby assessing the suitability of this experimental stroke model for the investigation of cognitive impairment after stroke.

METHODS

Photothrombotic cortical infarcts were induced in 19 adult male Wistar rats. Nineteen sham-operated animals served as controls. Using the Morris water maze, we analyzed the impact of photothrombotic stroke on both the acquisition of new memories and the recall of previously acquired memories. The cylinder test, the adhesive tape removal test, and the rotarod test were performed to investigate sensorimotor deficits.

RESULTS

Photothrombotic stroke significantly impaired the recall of previously acquired memories (P<0.05), whereas the acquisition of new memories remained largely intact. The analysis of the animals' swimming speed in the water maze and the rotarod test showed no confounding motor impairments after photothrombotic stroke. The adhesive tape removal test and the cylinder test revealed mild sensorimotor deficits in lesioned animals (P<0.05).

CONCLUSIONS

Photothrombotic cortical infarcts impair the recall of memories acquired before stroke, whereas the formation of new memories remains unimpaired. The observed deficits in the water maze are not confounded by disturbed motor functions. Overall, experimental photothrombotic strokes are well suited for the investigation of specific cognitive impairments after stroke.

Susac syndrome treated with subcutaneous immunoglobulin

BACKGROUND

Susac syndrome is a rare disease characterized by the triad of encephalopathy, branch retinal artery occlusion, and sensorineural hearing loss mainly affecting young women. The finding of antibodies against the endothelium in the sera of these patients has supported the hypothesis of an autoimmune endotheliopathy of the brain, inner ear and retina. Because of the rarity of the disease, treatment is based on the knowledge of case reports and small case series. Medical therapy consists of glucocorticoids, immunosuppressants, acetyl salicylic acid, and immunomodulatory agents such as intravenous immunoglobulin.

METHODS

We present the case histories of 2 young women with Susac syndrome presenting with several episodes of encephalopathy, branch retinal artery occlusions, and hearing loss that were treated with different immunosuppressive drugs, glucocorticoids and intravenous immunoglobulin. In the course of the disease, the treatment was successfully switched to subcutaneous immunoglobulin without any further relapse in both patients.

CONCLUSION

We conclude that the application of subcutaneous immunoglobulin is easy to learn, helps to reduce in-hospital costs and enables a more flexible everyday life. The treatment with subcutaneous immunoglobulin helps to reduce immunosuppressants and appears to prevent relapses.

Monocyte chemoattractant protein-1-deficiency results in altered blood-brain barrier breakdown after experimental stroke

BACKGROUND AND PURPOSE

Stroke-induced blood-brain barrier (BBB)-disruption can contribute to further progression of cerebral damage. There is rising evidence for a strong involvement of chemokines in postischemic BBB-breakdown. In a previous study, we showed that monocyte chemoattractant protein-1 (MCP-1)-deficiency results in a markedly reduced inflammatory reaction with decreased levels of interleukin-6, interleukin-1β, and granulocyte colony-stimulating factor after experimental stroke. With MCP-1 as one of the key players in stroke-induced inflammation, in this study, we investigated the influence of MCP-1 on poststroke BBB-disruption as well as transcription/translation of BBB-related genes/proteins after cerebral ischemia.

METHODS

Sixteen wild-type and 16 MCP-1(-/-) mice were subjected to 30 minutes of middle cerebral artery occlusion. By injecting high molecular-tracer, we compared the degree of BBB-disruption after middle cerebral artery occlusion. Real-time polymerase chain reactions and Western blot technique were used to compare tight-junction gene expression, protein secretion, and BBB-leakage.

RESULTS

Here, we report that MCP-1-deficiency results in a reduced BBB-leakage and a diminished expression of BBB-related genes occludin, zonula occludens-1, and zonula occludens-2. Real-time polymerase chain reactions and Western blot analysis revealed elevated claudin-5-levels in MCP-1(-/-) animals. MCP-1-deficiency resulted in reduced infarct sizes and an increased vascular accumulation of fluorescein-isothiocyanate-albumin.

CONCLUSIONS

The results of the study provide further insights into the molecular mechanisms of BBB-opening and may help to better understand the mechanisms of infarct development after cerebral ischemia.

Acute Cerebrovascular Disease in the Young

Background and Purpose—

Strokes have especially devastating implications if they occur early in life; however, only limited information exists on the characteristics of acute cerebrovascular disease in young adults. Although risk factors and manifestation of atherosclerosis are commonly associated with stroke in the elderly, recent data suggests different causes for stroke in the young. We initiated the prospective, multinational European study Stroke in Young Fabry Patients (sifap) to characterize a cohort of young stroke patients.

Methods—

Overall, 5023 patients aged 18 to 55 years with the diagnosis of ischemic stroke (3396), hemorrhagic stroke (271), transient ischemic attack (1071) were enrolled in 15 European countries and 47 centers between April 2007 and January 2010 undergoing a detailed, standardized, clinical, laboratory, and radiological protocol.

Results—

Median age in the overall cohort was 46 years. Definite Fabry disease was diagnosed in 0.5% (95% confidence interval, 0.4%–0.8%; n=27) of all patients; and probable Fabry disease in additional 18 patients. Males dominated the study population (2962/59%) whereas females outnumbered men (65.3%) among the youngest patients (18–24 years). About 80.5% of the patients had a first stroke. Silent infarcts on magnetic resonance imaging were seen in 20% of patients with a first-ever stroke, and in 11.4% of patients with transient ischemic attack and no history of a previous cerebrovascular event. The most common causes of ischemic stroke were large artery atherosclerosis (18.6%) and dissection (9.9%).

Conclusions—

Definite Fabry disease occurs in 0.5% and probable Fabry disease in further 0.4% of young stroke patients. Silent infarcts, white matter intensities, and classical risk factors were highly prevalent, emphasizing the need for new early preventive strategies.

Clinical Trial Registration Information—

URL: http://www.clinicaltrials.gov .Unique identifier: NCT00414583

[Concept for allocation of acute stroke patients: evaluation of the quality of diagnosis reached by the emergency medical services of Münster]

BACKGROUND

Acute stroke is a time- and expertise-critical emergency. An immediate and correct diagnosis by emergency medical services (EMS) in the prehospital phase and patient transfer to the nearest adequate hospital with a stroke unit is required for early treatment of acute stroke.

PATIENTS AND METHODS

We evaluated all patients who were admitted by the EMS of Münster to one of the two stroke units in the town between October 2008 and December 2010 with a diagnosis of acute stroke. Furthermore all patients were critically analyzed who were admitted without a diagnosis of acute stroke by the EMS but nonetheless had a stroke and the correct diagnosis was not found until examination in the neurological department.

RESULTS

We analyzed 615 patients who were admitted to the stroke units with the diagnosis of acute stroke. In 561 cases (91%) this diagnosis could be confirmed, but in 54 patients (9%) the diagnosis by the EMS was incorrect. Epileptic seizure was the most frequent false-positive diagnosis in this group of patients (39%; n = 21). Although the acute symptoms were caused by a stroke, the correct diagnosis was not defined by the EMS in 127 patients. This accounted for 18% of all patients admitted to the emergency departments by the EMS where ultimately a stroke was diagnosed. In 24% of these cases (n = 30) the emergency doctor missed the correct diagnosis, which meant 4% of all patients admitted by the EMS, finally diagnosed with an acute stroke. In all other cases in the group with a false-negative diagnosis (76% or 97 patients) an emergency doctor was not involved in the referral by the EMS.

CONCLUSION

Emergency medical services should be involved in the establishment of admission programs for acute stroke patients to provide the fastest means of transportation to a stroke unit. Coma, symptoms of posterior cerebral circulation and epileptic seizures cause difficulties in ensuring an immediate and correct diagnosis. Sending an emergency doctor to the scene increases diagnostic certainty which is essential to initiate early treatment.

[Stroke always with an emergency physician? - Pro]

Good management of acute stroke is dependent on time and expertise. In Germany emergency medical care by ambulance services sometimes occurs without an emergency physician being sent to the scene. By reviewing current literature the question of patient care in the ambulance with or without an emergency physician is discussed. Presence of an emergency physician at the scene results in high diagnostic accuracy, allows for invasive procedures to be carried out, and enables referral to a specialist centre with a stroke-unit. The "rendezvous" system of separate deployment of patient ambulance and emergency physician allow flexible assignment of the physician resulting in short response times. Current research does not support a turn away from the deployment of an emergency physician in cases of acute stroke.

Photochemically induced ischemic stroke in rats

Background

Photothrombosis was introduced as a model of ischemic stroke by Watson et al. in 1985. In the present paper, we describe a protocol to induce photothrombotic infarcts in rats.

Findings

The photosensitive dye Bengal Rose is intravenously administered and a laser beam is stereotactically positioned onto the skull. Illumination through the intact skull leads to local activation of Bengal Rose, which results in free radical formation, disturbance of endothelial function and thrombus formation in illuminated small cortical vessels.

Conclusions

Photochemically induced infarcts cause long-term sensorimotor deficits, allow long-term survival and are particularly suitable to assess the effectiveness of neuroregenerative therapies in chronic stroke studies.

Mobile wearable device for long term monitoring of vital signs

In long-term prevention and in rehabilitation of health of elderly people the recording of vital signs plays an important role. Especially the progress of rehabilitation can be deduced from the recording of an electrocardigram (ECG), blood pressure and body temperature. In this paper we present a wireless coupled recording device for long-term monitoring of these vital sign signals. We record the ECG, the blood pressure and the skin temperature and include a 3D-acceleration sensor for the determination of the movements during recording. To deal with motion artifacts in all recorded properties we use data fusion to reject or correct distorted vital sign signals.

Cost and affordability of healthy food in rural South Australia

INTRODUCTION

As in many other countries, Australian consumers have recently had to accommodate increases in costs of basic food, and during the financial year 2007-2008 overall food prices rose by nearly 4%. Food costs are mediating factors in food choice, especially for low-income groups, where food security is often tenuous. There are reports that rural populations may have higher levels of food insecurity, although the evidence is often contradictory.

METHODS

To assess cost and affordability of food in rural areas this study used the Healthy Food Basket (HFB) methodology, which has been applied in a number of settings. The HFBs were costed at supermarkets and stores in different locations with different degrees of rurality.

RESULTS

Compared with metropolitan areas, healthy food is more expensive in rural areas; costs are even higher in more remote areas. The overall affordability of HFB in rural areas was not significantly different from metro areas. The main difference concerned low socio-economic status (SES) groups, where the proportion of household income spent on the HFB was three times that of higher SES groups.

CONCLUSIONS

The unaffordability of healthy food, or 'food stress' in low SES groups is a concern, especially when this group carries the greatest burden of diet-related disease. Findings suggest that there is a need to consider both rurality and SES when developing policy responses to decrease the cost and increase the affordability of healthy foods in rural and remote areas.