Postinhibitory excitation in motoneurons can be facilitated by hyperpolarization-activated inward currents: A simulation study

Postinhibitory excitation is a transient overshoot of a neuron's baseline firing rate following an inhibitory stimulus and can be observed in vivo in human motoneurons. However, the biophysical origin of this phenomenon is still unknown and both reflex pathways and intrinsic motoneuron properties have been proposed. We hypothesized that postinhibitory excitation in motoneurons can be facilitated by hyperpolarization-activated inward currents (h-currents). Using an electrical circuit model, we investigated how h-currents can modulate the postinhibitory response of motoneurons. Further, we analyzed the spike trains of human motor units from the tibialis anterior muscle during reciprocal inhibition. The simulations revealed that the activation of h-currents by an inhibitory postsynaptic potential can cause a short-term increase in a motoneuron's firing probability. This result suggests that the neuron can be excited by an inhibitory stimulus. In detail, the modulation of the firing probability depends on the time delay between the inhibitory stimulus and the previous action potential. Further, the postinhibitory excitation's strength correlates with the inhibitory stimulus's amplitude and is negatively correlated with the baseline firing rate as well as the level of input noise. Hallmarks of h-current activity, as identified from the modeling study, were found in 50% of the human motor units that showed postinhibitory excitation. This study suggests that h-currents can facilitate postinhibitory excitation and act as a modulatory system to increase motoneuron excitability after a strong inhibition.

Supplementary orthopaedic screening for children and adolescents to prevent permanent skeletal deformities - protocol for the "OrthoKids" study

BACKGROUND

Skeletal deformities (SD) in children and adolescents can lead to arthritic conditions, impairment of quality of life, and high treatment costs in the long term. However, comprehensive data on the prevalence of SDs in children and adolescents are limited and it remains therefore unclear whether there is a healthcare gap. "OrthoKids" is a project that addresses this evidence gap by implementing an orthopaedic screening for children and adolescents that supplements existing detection examinations within statutory standard care in Germany.

OBJECTIVE

To detect SDs so that they can be treated as needed at an early stage.

METHODS

The implementation of the supplementary orthopaedic screening will be evaluated through an exploratory cohort study that is set up in the German state Baden-Wuerttemberg. 20,000 children and adolescents aged 10 to 14 years will be recruited as a prospective cohort. A retrospective control cohort will be formed based on claims data provided by two cooperating statutory health insurances (SHIs). Participating children and adolescents receive a one-time orthopaedic screening. If at least one SD is diagnosed, treatment will be provided as part of the statutory standard care. Within the scope of the project, a follow-up examination will be performed after one year. An IT-platform will complement the study. The primary outcome measure is the point prevalence of scoliosis, genu varum/valgum, hip dysplasia, and flat feet. Secondary outcome measures are (i) the point prevalence of further less common SDs, (ii) health-related quality of life (HRQoL), (iii) sports ability based on activity (physical/athletic), physical constraints, and (sports) injuries, as well as (iv) monetary consequences of the orthopaedic screenings' implementation. Implementation determinants will be evaluated, too.

DISCUSSION

If the supplementary orthopaedic screening proves to be viable, it could be considered as a supplementary examination for children and adolescents within the frame of SHI in Germany. This could relieve the burden of disease among children and adolescents with SDs. In addition, it could disburden SHIs in the medium to long term.

TRIAL REGISTRATION

The OrthoKids study was registered in the German Clinical Trials Registry (Deutsches Register Klinischer Studien (DRKS)) on 26th July 2022 under the number 00029057.

Linking cortex and contraction-Integrating models along the corticomuscular pathway

Computational models of the neuromusculoskeletal system provide a deterministic approach to investigate input-output relationships in the human motor system. Neuromusculoskeletal models are typically used to estimate muscle activations and forces that are consistent with observed motion under healthy and pathological conditions. However, many movement pathologies originate in the brain, including stroke, cerebral palsy, and Parkinson's disease, while most neuromusculoskeletal models deal exclusively with the peripheral nervous system and do not incorporate models of the motor cortex, cerebellum, or spinal cord. An integrated understanding of motor control is necessary to reveal underlying neural-input and motor-output relationships. To facilitate the development of integrated corticomuscular motor pathway models, we provide an overview of the neuromusculoskeletal modelling landscape with a focus on integrating computational models of the motor cortex, spinal cord circuitry, α-motoneurons  and skeletal muscle in regard to their role in generating voluntary muscle contraction. Further, we highlight the challenges and opportunities associated with an integrated corticomuscular pathway model, such as challenges in defining neuron connectivities, modelling standardisation, and opportunities in applying models to study emergent behaviour. Integrated corticomuscular pathway models have applications in brain-machine-interaction, education, and our understanding of neurological disease.

Quantitative assessment can stabilize indirect reciprocity under imperfect information

The field of indirect reciprocity investigates how social norms can foster cooperation when individuals continuously monitor and assess each other's social interactions. By adhering to certain social norms, cooperating individuals can improve their reputation and, in turn, receive benefits from others. Eight social norms, known as the "leading eight," have been shown to effectively promote the evolution of cooperation as long as information is public and reliable. These norms categorize group members as either 'good' or 'bad'. In this study, we examine a scenario where individuals instead assign nuanced reputation scores to each other, and only cooperate with those whose reputation exceeds a certain threshold. We find both analytically and through simulations that such quantitative assessments are error-correcting, thus facilitating cooperation in situations where information is private and unreliable. Moreover, our results identify four specific norms that are robust to such conditions, and may be relevant for helping to sustain cooperation in natural populations.

SARS-CoV-2 Seroprevalence in Germany: results from the second wave of the RKI-SOEP study

Introduction

The first wave of the “Corona Monitoring bundesweit” (RKI-SOEP) study showed that shortly before the start of the German vaccination program only about 2% of adults (> 18 years) had already experienced SARS-CoV-2 infection and more than half of these cases had been detected and notified. The objectives of the second wave of this study are to further investigate the spread of SARS-CoV-2 in Germanýs population aged over 14 years. It aims to determine the seroprevalence of infection- and vaccine-induced IgG antibodies against SARS-CoV-2. Finally, it examines health, demographic and socioeconomic risk and protective factors for infection and vaccine acceptance.

Methods

From November 2021 to February 2022, the second wave of this cross-sectional study collected biospecimens (capillary blood samples) and interview data, including information on infection and vaccination, from a nationwide population sample drawn from the German Socio-Economic Panel (SOEP). The dried self-collected blood samples were then analyzed for the detection of SARS-CoV-2 IgG antibodies by Euroimmun ELISA assay.

Results

Based on preliminary, unweighted data of around 11,000 participants aged >14 years (52% response rate), we expect the final seroprevalence of SARS-CoV-2 antibodies to be in the range of 80 to 90%. Thus, around 10 to 20% of the German population may still be susceptible to a severe disease progression because they are neither infected nor vaccinated. Final results, weighted for non-response and adjusted for test sensitivity and specificity, will be presented.

Conclusions

The RKI-SOEP-2 study will be pivotal in both, contributing to an improved understanding of SARS-CoV-2 propagation in different regional and sub-group settings and in identifying vulnerable target groups that need to be protected against future infections.

Key messages

• Dried blood self-sampling in a nationwide sample is a robust tool to estimate seroprevalence at a population level.

• As of February 2022, presumably 80 to 90% of the German population has previously been infected and/or vaccinated against SARS-CoV-2.

Direct reciprocity between individuals that use different strategy spaces

In repeated interactions, players can use strategies that respond to the outcome of previous rounds. Much of the existing literature on direct reciprocity assumes that all competing individuals use the same strategy space. Here, we study both learning and evolutionary dynamics of players that differ in the strategy space they explore. We focus on the infinitely repeated donation game and compare three natural strategy spaces: memory-1 strategies, which consider the last moves of both players, reactive strategies, which respond to the last move of the co-player, and unconditional strategies. These three strategy spaces differ in the memory capacity that is needed. We compute the long term average payoff that is achieved in a pairwise learning process. We find that smaller strategy spaces can dominate larger ones. For weak selection, unconditional players dominate both reactive and memory-1 players. For intermediate selection, reactive players dominate memory-1 players. Only for strong selection and low cost-to-benefit ratio, memory-1 players dominate the others. We observe that the supergame between strategy spaces can be a social dilemma: maximum payoff is achieved if both players explore a larger strategy space, but smaller strategy spaces dominate.

Direct reciprocity can lead to cooperation between individuals who meet in repeated encounters. The shadow of the future casts an incentive to cooperate. If I cooperate today, you may cooperate tomorrow. But if I defect today, you may defect tomorrow. In most studies of direct reciprocity it is assumed that both players explore the same space of possible strategies. In contrast, here we study interactions between players that use different strategy spaces and therefore utilize different memory capacities. Surprisingly, we find that more complex strategy spaces often lose out against simpler ones. The social optimum, however, is achieved if all players use the more complex space. Therefore, the game between strategy spaces becomes a higher order social dilemma.

Ypd1 Is an Essential Protein of the Major Fungal Pathogen Aspergillus fumigatus and a Key Element in the Phosphorelay That Is Targeted by the Antifungal Drug Fludioxonil

Aspergillus fumigatus is a major fungal pathogen causing life threatening infections in immunocompromised humans and certain animals. The HOG pathway is for two reasons interesting in this context: firstly, it is a stress signaling pathway that contributes to the ability of this pathogen to adapt to various stress conditions and secondly, it is the target of antifungal agents, such as fludioxonil or pyrrolnitrin. In this study, we demonstrate that Ypd1 is an essential protein in A. fumigatus. As the central component of the multistep phosphorelay it represents the functional link between the sensor histidine kinases and the downstream response regulators SskA and Skn7. A GFP-Ypd1 fusion was found to reside in both, the cytoplasm and the nucleus and this pattern was only slightly affected by fludioxonil. A strain in which the ypd1 gene is expressed from a tet-on promoter construct is unable to grow under non-inducing conditions and shows the characteristic features of A. fumigatus wild type hyphae treated with fludioxonil. Expression of wild type Ypd1 prevents this lethal phenotype, but expression of an Ypd1 mutant protein lacking the conserved histidine at position 89 was unable to do so, which confirms that A. fumigatus Ypd1 is a phosphotransfer protein. Generation of ypd1tet-on variants of several mutant strains revealed that the lethal phenotype associated with low amounts of Ypd1 depends on SskA, but not on TcsC or Skn7. The ΔsskA ypd1tet-on, but not the ΔsskAΔskn7 ypd1tet-on mutant, was sensitive to fludioxonil, which underlines the importance of Skn7 in this context. We finally succeeded to delete ypd1, but only if sskA and skn7 were both inactivated, not in a ΔsskA single mutant. Hence, a deletion of ypd1 and an inactivation of Ypd1 by fludioxonil result in similar phenotypes and the two response regulators SskA and Skn7 are involved in both processes albeit with a different relative importance.

The evolution of indirect reciprocity under action and assessment generosity

Indirect reciprocity is a mechanism for the evolution of cooperation based on social norms. This mechanism requires that individuals in a population observe and judge each other's behaviors. Individuals with a good reputation are more likely to receive help from others. Previous work suggests that indirect reciprocity is only effective when all relevant information is reliable and publicly available. Otherwise, individuals may disagree on how to assess others, even if they all apply the same social norm. Such disagreements can lead to a breakdown of cooperation. Here we explore whether the predominantly studied 'leading eight' social norms of indirect reciprocity can be made more robust by equipping them with an element of generosity. To this end, we distinguish between two kinds of generosity. According to assessment generosity, individuals occasionally assign a good reputation to group members who would usually be regarded as bad. According to action generosity, individuals occasionally cooperate with group members with whom they would usually defect. Using individual-based simulations, we show that the two kinds of generosity have a very different effect on the resulting reputation dynamics. Assessment generosity tends to add to the overall noise and allows defectors to invade. In contrast, a limited amount of action generosity can be beneficial in a few cases. However, even when action generosity is beneficial, the respective simulations do not result in full cooperation. Our results suggest that while generosity can favor cooperation when individuals use the most simple strategies of reciprocity, it is disadvantageous when individuals use more complex social norms.

Changes in Loss Sensitivity During Treatment in Concurrent Disorders Inpatients: A Computational Model Approach to Assessing Risky Decision-Making

BACKGROUND

Recent studies have employed computational modeling to characterize deficits in aspects of decision-making not otherwise detected using traditional behavioral task outcomes. While prospect utility-based modeling has shown to differentiate decision-making patterns between users of different drugs, its relevance in the context of treatment has yet to be examined. This study investigated model-based decision-making as it relates to treatment outcome in inpatients with co-occurring mental health and substance use disorders.

METHODS

50 patients (Mage = 38.5, SD = 11.4; 16F) completed the Cambridge Gambling Task (CGT) within 2 weeks of admission (baseline) and 6 months into treatment (follow-up), and 50 controls (Mage = 31.9, SD = 10.0; 25F) completed CGT under a single outpatient session. We evaluated 4 traditional CGT outputs and 5 decisional processes derived from the Cumulative Model. Psychiatric diagnoses and discharge data were retrieved from patient health records.

RESULTS

Groups were similar in age, sex, and premorbid IQ. Differences in years of education were included as covariates across all group comparisons. All patients had ≥1 mental health diagnosis, with 80% having >1 substance use disorder. On the CGT, patients showed greater Deliberation Time and Delay Aversion than controls. Estimated model parameters revealed higher Delayed Reward Discounting, and lower Probability Distortion and Loss Sensitivity in patients relative to controls. From baseline to follow-up, patients (n = 24) showed a decrease in model-derived Loss Sensitivity and Color Choice Bias. Lastly, poorer Quality of Decision-Making and Choice Consistency, and greater Color Choice Bias independently predicted higher likelihood of treatment dropout, while none were significant in relation to treatment length of stay.

CONCLUSION

This is the first study to assess a computational model of decision-making in the context of treatment for concurrent disorders. Patients were more impulsive and slower to deliberate choice than controls. While both traditional and computational outcomes predicted treatment adherence in patients, findings suggest computational methods are able to capture treatment-sensitive aspects of decision-making not accessible via traditional methods. Further research is needed to confirm findings as well as investigate the relationship between model-based decision-making and post-treatment outcomes.

Characterization of Electromechanical Delay Based on a Biophysical Multi-Scale Skeletal Muscle Model

Skeletal muscles can be voluntary controlled by the somatic nervous system yielding an active contractile stress response. Thereby, the active muscle stresses are transmitted to the skeleton by a cascade of connective tissue and thus enable motion. In the context of joint perturbations as well as the assessment of the complexity of neural control, the initial phase of the muscle-tendon system's stress response has a particular importance and is analyzed by means of electromechanical delay (EMD). EMD is defined as the time lag between the stimulation of a muscle and a measurable change in force output. While EMD is believed to depend on multiple structures / phenomena, it is hard to separate their contributions experimentally. We employ a physiologically detailed, three-dimensional, multi-scale model of an idealized muscle-tendon system to analyze the influence of (i) muscle and tendon length, (ii) the material behavior of skeletal muscle and tendon tissue, (iii) the chemo-electro-mechanical behavior of the muscle fibers and (iv) neural control on EMD. Comparisons with experimental data show that simulated EMD values are within the physiological range, i.e., between 6.1 and 68.6 ms, and that the model is able to reproduce the characteristic EMD-stretch curve, yielding the minimum EMD at optimal length. Simulating consecutive recruitment of motor units increases EMD by more than 20 ms, indicating that during voluntary contractions neural control is the dominant factor determining EMD. In contrast, the muscle fiber action potential conduction velocity is found to influence EMD even of a 27 cm long muscle by not more than 3.7 ms. We further demonstrate that in conditions where only little pre-stretch is applied to a muscle-tendon system, the mechanical behavior of both muscle and tendon tissue considerably impacts EMD. Predicting EMD for different muscle and tendon lengths indicates that the anatomy of a specific muscle-tendon system is optimized for its function, i.e., shorter tendon lengths are beneficial to minimize the neural control effort for muscles primary acting as motor in concentric contractions.

Indirect reciprocity with private, noisy, and incomplete information

Indirect reciprocity is a mechanism for cooperation based on shared moral systems and individual reputations. It assumes that members of a community routinely observe and assess each other and that they use this information to decide who is good or bad, and who deserves cooperation. When information is transmitted publicly, such that all community members agree on each other's reputation, previous research has highlighted eight crucial moral systems. These "leading-eight" strategies can maintain cooperation and resist invasion by defectors. However, in real populations individuals often hold their own private views of others. Once two individuals disagree about their opinion of some third party, they may also see its subsequent actions in a different light. Their opinions may further diverge over time. Herein, we explore indirect reciprocity when information transmission is private and noisy. We find that in the presence of perception errors, most leading-eight strategies cease to be stable. Even if a leading-eight strategy evolves, cooperation rates may drop considerably when errors are common. Our research highlights the role of reliable information and synchronized reputations to maintain stable moral systems.

[Recommendations for the Stepwise Occupational Reintegration: Can the Characteristic of the Patients Explain the Differences Between the Rehabilitation Centers?]

BACKGROUND

The first step to initiate a stepwise occupational reintegration (SOR) is the recommendation of the rehabilitation centers. Therefore rehabilitation centers have a significant impact on the use of SOR. There is evidence that the recommendation rate between the rehabilitation centers differs clearly. The present survey therefore analyses in detail the differences of the recommendation rate and examines which patient-related factors could explain the differences.

METHODS

This study is based on analysis of routine data provided by the German pension insurance in Baden-Württemberg (Rehabilitationsstatistikdatenbasis 2013; RSD). In the analyses rehabilitation measures were included if they were conducted by employed patients (18-64 years) with a muscular-skeletal system disease or a disorder of the connective tissue. Logistic regression models were performed to explain the differences in the recommendation rate of the rehabilitation centers.

RESULTS

The data of 134 853 rehabilitation measures out of 32 rehabilitation centers were available. The recommendation rate differed between the rehabilitation centers from 1.36-18.53%. The logistic regression analysis showed that the period of working incapacity 12 month before the rehabilitation and the working capacity on the current job were the most important predictors for the recommendation of a SOR by the rehabilitation centers. Also the rehabilitation centers themselves have an important influence.

DISCUSSION

The results of this survey indicate that the characteristic of the patients is an important factor for the recommendation of SOR. Additionally the rehabilitation centers themselves have an influence on the recommendation of SOR. The results point to the fact that the rehabilitation centers use different criteria by making a recommendation.

[The User Survey on the Revision of the Classification of Therapeutic Procedures]

INTRODUCTION

An extensive user survey was conducted in the context of updating the Classification of Therapeutic Procedures (KTL 2015). This paper reflects the results of the user survey and raises critical discussion points.

METHODS

The user survey was sent to all rehabilitation centers contracted by the German pension insurance as well as professional associations. The user survey was available both as a paper questionnaire and as an online version. The feedback of the user survey provided an important basis for the revision of the KTL.

RESULT

The survey yielded 1,868 suggestions from 360 users. Most of them related to chapters E ("occupational therapy, work therapy, other functional therapy") and C ("information, motivation, training"). The change from German diplomas to the international Bachelor's and Master's degrees, and the inclusion of diagnostic and work-related procedures were the main focus of the user feedback.

CONCLUSION

For the revision of the KTL, the user survey provided valuable information. Only by the inclusion of practitioners can the KTL meet the requirements of realistic and comprehensive acquisition of data on therapeutic procedures also in future.

[Bilateral Instability of the Interphalangeal Articulation of the Thumb in Hajdu-Cheney Syndrome]

We present the case of a 52-year-old lady suffering from Hajdu-Cheney syndrome, a rare hereditary disease, which was referred to our clinic on the basis of progressive instability of the interpalangeal articulations of both thumbs. Even if acroosteolysis of the distal phalangeal bones is typical for this disease, to the best of our knowledge the interphalangeal instability has not been described before.

[Quality assurance in outpatient neurological rehabilitation: measuring the effects of rehabilitation with the competency rating scale]

BACKGROUND

So far, there are only few studies concerning the outcome of outpatient neurological rehabilitation in Germany. Considering the statutory obligations of quality assurance there is an urgent need of appropriate instruments to assess the rehabilitation outcome. The aim of this study was to assess the appropriateness of the Competency Rating Scale (CRS), which was used to measure rehabilitation outcome, and to collect data of the effects of outpatient neurological rehabilitation as a measure of rehabilitation outcome.

METHODS

The basis of this study was data collected between 2008 and 2011. During that period the data of all patients of an outpatient neurological rehabilitation center were consecutively collected. There were no exclusion criteria. To measure rehabilitation outcome patients' self ratings with the CRS were used. To check the appropriateness of the CRS the dropout rate and the missing values were analysed. In addition, the patients' self ratings were compared with the data of a near relative rating with the CRS.

RESULTS

On examining the entire group of patients, statistically significant improvements over time were found in the motor as well as in the cognitive-psychosocial areas. The analysis of the data with regard to the appropriateness of the CRS showed considerable ceiling effects and a high dropout rate. Differences between the self and the near relative ratings could be detected.

CONCLUSION

For the overall group of patients positive effects of outpatient neurological rehabilitation can be proven. The assessment instrument used in this study is only partially suitable for assessing the outcome of outpatient neurological rehabilitation. The comparison of self and near relative ratings can systematically be used in the therapy process.

LCD vs. E-ink: An Analysis of the Reading Behavior

Electronic books (e-book) are an interesting option compared to classic paper books. Most e-reading devices of the first generation were based on e-ink technology. With the appearance of the Apple iPad on the market, TFT-LCDs became important in the field of e-reading. Both technologies have advantages and disadvantages but the question remains whether one or the other technology is better for reading. In the present study we analyzed and compared reading behavior when reading on e-inkreader (e-ink displays) and on tablets (TFT-LCDs) as measured by eye-tracking. The results suggest that the reading behavior on tablets is indeed very similar to the reading behavior on e-ink-reader. Participants showed no difference in fixation duration. Significant differences in reading speed and in the proportion of regressive saccades suggest that tablets, under special artificial light conditions, may even provide better legibility.

Dynamics of red blood cells and vesicles in microchannels of oscillating width

We have studied the dynamics of red blood cells and fluid lipid vesicles in hydrodynamic flow fields created by microchannels with periodically varying channel width. For red blood cells we find a transition from a regime with oscillating tilt angle and fixed shape to a regime with oscillating shape with increasing flow velocity. We have determined the crossover to occur at a critical ratio L(y)/v(m) ≈ 2.2 × 10⁻³ s with channel width L(y) and red blood cell velocity v(m). These oscillations are superposed by shape transitions from a discocyte to a slipper shape at low velocities and a slipper to parachute transition at high flow velocities.

Assessment of phagocytic and antimicrobial activity of human granulocytes

A microassay for assessing two functions of polymorphonuclear leukocytes in the presence or absence of complement is presented. Requiring only minute amounts of blood (0.1 ml) and a minimum of laboratory equipment (microscope, incubator, and centrifuge), it allows the quantitation of phagocytosis and intracellular killing of microorganisms by leukocytes. To demonstrate the value of this assay, the phagocytic and microbicidal activity of leukocytes from healthy subjects and patients against Candida albicans was investigated. Apart from individual cases, no differences in the phagocytic activity between groups of healthy subjects and patients with candida vaginitis or different types of cancer could be found. However, the killing capacity of the leukocytes from women with recurrent candida vaginitis was reduced. The leukocytes of one patient showing a very low killing capacity lacked myeloperoxidase. Also, low values of killing were seen with leukocytes from three patients suffering from osteosarcoma, chronic lymphatic leukemia, or Hodgkins disease.

Surface acoustic wave actuated cell sorting (SAWACS)

We describe a novel microfluidic cell sorter which operates in continuous flow at high sorting rates. The device is based on a surface acoustic wave cell-sorting scheme and combines many advantages of fluorescence activated cell sorting (FACS) and fluorescence activated droplet sorting (FADS) in microfluidic channels. It is fully integrated on a PDMS device, and allows fast electronic control of cell diversion. We direct cells by acoustic streaming excited by a surface acoustic wave which deflects the fluid independently of the contrast in material properties of deflected objects and the continuous phase; thus the device underlying principle works without additional enhancement of the sorting by prior labelling of the cells with responsive markers such as magnetic or polarizable beads. Single cells are sorted directly from bulk media at rates as fast as several kHz without prior encapsulation into liquid droplet compartments as in traditional FACS. We have successfully directed HaCaT cells (human keratinocytes), fibroblasts from mice and MV3 melanoma cells. The low shear forces of this sorting method ensure that cells survive after sorting.

Induction of complete and sustained remission of rheumatoid pachymeningitis by rituximab

Aseptic pachymeningitis is a rare and serious complication of rheumatoid arthritis (RA). Herein, we describe a patient with rheumatoid factor-positive and anti-cyclic citrullinated peptide-positive RA who experienced a focal seizure, with aphasia and convulsions of the right side of the body. The findings of magnetic resonance imaging and histologic analysis led to a diagnosis of rheumatoid pachymeningitis. Because the patient had a large number of CD20-expressing B lymphocytes, therapy with rituximab was started and has resulted in complete and sustained remission of both the pachymeningitis and the RA for >2 years. Despite a decrease in immunoglobulins, the patient has remained free of infections, which illustrates the favorable outcome that can result from therapeutic B cell depletion in this potentially lethal manifestation of RA.

Relapse following discontinuation of imatinib mesylate therapy for FIP1L1/PDGFRA-positive chronic eosinophilic leukemia: implications for optimal dosing

Although imatinib is clearly the treatment of choice for FIP1L1/PDGFRA-positive chronic eosinophilic leukemia (CEL), little is known about optimal dosing, duration of treatment, and the possibility of cure in this disorder. To address these questions, 5 patients with FIP1L1/PDGFRA-positive CEL with documented clinical, hematologic, and molecular remission on imatinib (400 mg daily) and without evidence of cardiac involvement were enrolled in a dose de-escalation trial. The imatinib dose was tapered slowly with close follow-up for evidence of clinical, hematologic, and molecular relapse. Two patients with endomyocardial fibrosis were maintained on imatinib 300 to 400 mg daily and served as controls. All 5 patients who underwent dose de-escalation, but neither of the control patients, experienced molecular relapse (P < .05). None developed recurrent symptoms, and eosinophil counts, serum B12, and tryptase levels remained suppressed. Reinitiation of therapy at the prior effective dose led to molecular remission in all 5 patients, although 2 patients subsequently required increased dosing to maintain remission. These data are consistent with suppression rather than elimination of the clonal population in FIP1L1/PDGFRA-positive CEL and suggest that molecular monitoring may be the most useful method in determining optimal dosing without the risk of disease exacerbation. This trial was registered at http://www.clinicaltrials.gov as no. NCT00044304.

Probing the Kondo density of states in a three-terminal quantum ring

We have measured the Kondo effect in a quantum ring connected to three terminals. In this configuration nonlinear transport measurements allow us to check which lead contributes to the Kondo density of states (DOS) and which does not. The ring geometry allows a fine-tuning of the coupling to each lead through the Aharonov-Bohm effect via application of a magnetic field. When the ring is connected to two strongly and one weakly coupled leads, conductance through the weakly coupled lead provides a direct measurement of the DOS in the Kondo regime. By applying a bias between the two strongly coupled leads, we demonstrate directly the splitting of the out-of-equilibrium Kondo DOS.

Education in end-of-life care: bridging disciplinary and institutional boundaries

This paper describes the development of an interdisciplinary, interinstitutional seminar in palliative care for South Dakota students in medicine, nursing, pharmacy, chaplaincy, and social work. Student outcomes from six seminars conducted during 2001-2004 are reported, and recommendations for future educational efforts are outlined.

Are living beings in the state of self-organized criticality? A new interpretation of data on work incapacity due to low back pain

Using data published elsewhere I demonstrate in this paper that the frequency distribution of the duration of work incapacity from low back pain follows a power law. Power laws are not common in medicine and the question arises why we can find one here. The peculiarity of the data considered here is that they embrace not only the passive reaction but also the whole spectrum of possible active responses of a living being to a disturbance. For the duration of sick leave due to low back pain is not only influenced by the defect a person is affected by, but even more dependent on how he or she copes with it. Coping comprises a broad range of possibilities from denial of the disability to its aggravation, from therapy to malingering. In contrast to the scientific ideal none of these faculties has been excluded in the data used here. They concern the whole living being. Power laws are typical for systems in the state of self-organized criticality. The system involved in the case of low back pain is the whole living human being with all its possibilities to react and to respond. Thus, my findings support empirically the hypothesis that living beings are in the state of self-organized criticality.

Ketamine-induced deficits in auditory and visual context-dependent processing in healthy volunteers: implications for models of cognitive deficits in schizophrenia

BACKGROUND

In patients with schizophrenia, deficient generation of mismatch negativity (MMN)-an event-related potential (ERP) indexing auditory sensory ("echoic") memory-and a selective increase of "context dependent" ("BX") errors in the "A-X" version of the Continuous Performance Test (AX-CPT) indicate an impaired ability to form and use transient memory traces. Animal and human studies implicate deficient N-methyl-D-aspartate receptor (NMDAR) functioning in such abnormalities. In this study, effects of the NMDAR antagonists ketamine on MMN generation and AX-CPT performance were investigated in healthy volunteers to test the hypothesis that NMDARs are critically involved in human MMN generation, and to assess the nature of ketamine-induced deficits in AX-CPT performance.

METHODS

In a single-blind placebo-controlled study, 20 healthy volunteers underwent an infusion with subanesthetic doses of ketamine. The MMN-to-pitch and MMN-to-duration deviants were obtained while subjects performed an AX-CPT.

RESULTS

Ketamine significantly decreased the peak amplitudes of the MMN-to-pitch and MMN-to-duration deviants by 27% and 21%, respectively. It induced performance deficits in the AX-CPT characterized by decreased hit rates and specific increases of errors (BX errors), reflecting a failure to form and use transient memory traces of task relevant information.

CONCLUSIONS

The NMDARs are critically involved in human MMN generation. Deficient MMN in schizophrenia thus suggests deficits in NMDAR-related neurotransmission. N-methyl-D-aspartate receptor dysfunction may also contribute to the impairment of patients with schizophrenia in forming and using transient memory traces in more complex tasks, such as the AX-CPT. Thus, NMDAR-related dysfunction may underlie deficits in transient memory at different levels of information processing in schizophrenia. Arch Gen Psychiatry. 2000;57:1139-1147.

[Process quality in oncologic rehabilitation. Viewpoint of the Professional Committee of Rehabilitation, After-care and Social Medicine of the German Cancer Society]

The article concerns itself with the issue of process quality in inpatient institutions for oncological rehabilitation and expresses the viewpoint of the German Cancer Society's Section for Rehabilitation, Aftercare and Social Medicine (ARNS). Standards for the organization of patients' access to the rehabilitation clinic, for the design of oncological-rehabilitational diagnostics, for the formation of therapeutic strategies and the rehabilitative services offered will be described.

[Structural quality of oncologic rehabilitation. Viewpoint of the Professional Committee of Rehabilitation, After-care and Social Medicine of the German Cancer Society]

The article discusses the structural requirements on inpatient institutions for oncological rehabilitation and expresses the position of the German Cancer Society's Section for Rehabilitation, Aftercare and Social Medicine (ARNS). Standards are formulated concerning spatial conditions, technical equipment, personnel (number, professions, qualification) and networking conditions with regard to all cancer diagnoses. These standards are also discussed with regard to various specific cancer diagnoses such as, for example, breast cancer, gastrointestinal tumours, lung tumours and brain tumours, as well as with regard to patients in specific treatment measures such as bone marrow and stem cell transplantation.

[Outcome quality in oncologic rehabilitation. Viewpoint of the Professional Committee of Rehabilitation, After-Care and Social Medicine of the German Cancer Society]

The article is concerned with the basic ideas of outcome quality within the field of oncological rehabilitation and expresses the position which is held by the Section for Rehabilitation, Aftercare and Social Medicine within the German Cancer Society. The authors explicitly express the necessity of rehabilitation-specific goals and corresponding outcome criteria as opposed to the goals and criteria of acute oncological treatment. In the formulation of goals and criteria, the medical-somatic, occupational-rehabilitative, social and psychological levels are considered. The consequences which arise from these outcome criteria with regard to the rehabilitative health care system for cancer patients are discussed.

Characteristics and prognosis of myocardial infarction in patients with normal coronary arteries

STUDY OBJECTIVES

Myocardial infarction with angiographically normal coronary arteries (MINC) is a life-threatening event with many open questions for physicians and patients. There are little data concerning the prognosis for patients with MINC.

DESIGN

Retrospective follow-up study.

SETTING

Tertiary referral center.

PATIENTS

Patients with MINC were investigated and compared to age- and sex-matched control subjects with myocardial infarction due to coronary artery disease (CAD). The patients were examined clinically using stress exercise and hyperventilation tests. Migraine and Raynaud's symptoms were determined by means of a standardized questionnaire. Serum lipoproteins; the seroprevalence of cytomegalovirus, Helicobacter pylori, and Chlamydia pneumoniae infections; and the most frequent causes of thrombophilia were assessed.

MEASUREMENTS AND RESULTS

From > 4,300 angiographies that were performed between 1989 and 1996, 21 patients with MINC were identified. The mean +/- SD patient age at the time of myocardial infarction was 42 +/- 7.5 years. When compared to control subjects (n = 21), patients with MINC had fewer risk factors for CAD. In contrast, MINC patients had more frequent febrile reactions prior to myocardial infarction (six patients vs zero patients; p < 0.05), and the migraine score was significantly higher (7.1 +/- 6.3 vs 2.2 +/- 4.1; p < 0.01). The seroprevalence of antibodies against cytomegalovirus, C pneumoniae, and H pylori tended to be higher in patients with MINC and CAD as compared to matched healthy control subjects. Three patients with MINC vs none with CAD had coagulopathy. During follow-up (53 +/- 37 months), no major cardiac event occurred in the MINC group; no patients with MINC vs nine with CAD (p = 0.0001) underwent repeated angiography.

CONCLUSION

High migraine score and prior febrile infection together with a lower cardiovascular risk profile are compatible with an inflammatory and a vasomotor component in the pathophysiology of the acute coronary event in MINC patients. The prognosis for these patients is excellent.

Sport related proximal femoral fractures: a retrospective review of 31 cases treated in an eight year period

In an eight year period, 31 patients with proximal femoral fractures resulting from sports accidents were treated by implantation of either a Gamma nail or a dynamic hip screw. Return to work or sports and the time to bone healing did not differ very much between the treatments. Gamma nailing was clearly the best with regard to stability and time to full mobilisation (4.5 days), but required 39 minutes to perform compared with insertion of a dynamic hip screw (27 minutes). The incidence of complications and malalignments did not differ very much between the two, although, when Gamma nailing was first used in the authors' clinic, more intraoperative complications occurred than with the dynamic hip screw. Stable pertrochanteric fractures may be treated with a dynamic hip screw. Unstable pertrochanteric or subtrochanteric fractures are treated with a Gamma nail at the authors' institution.

Comparison of ender nails, dynamic hip screws, and Gamma nails in the treatment of peritrochanteric femoral fractures

Three hundred seventy-six patients with peritrochanteric fractures treated over a 10-year period were reviewed. In 85 patients treated with Ender nailing, the most frequent complications were leg shortening (34), external rotation failure (21), and postoperative distal gliding of the nails (7). In 183 patients treated with dynamic hip screws or a 95 degree condylar or a 130 degree blade plate, 3 presented with infection, 5 with instability, and 4 with femoral head necrosis. In 105 patients treated with Gamma nailing, the most serious complications were infections (3), inward rotation failure (2), postoperative bleeding at the insertion site (2), and shaft fracture (1). Because of its inherent instability, Ender nailing is no longer used. The implantation technique for the dynamic hip screw is safer and simpler than the various models of the ASIF blade plate. However, the dynamic hip screw has been superseded by the Gamma nail because of its absolute stability. In the beginning, Gamma nailing was technically more demanding with a higher number of intraoperative complications. In this study, the number of malalignments did not differ significantly between the dynamic hip screw (14) and the Gamma nail (11), but was high with Ender nailing (56).

[Lifelong heavy agricultural work and development of arthrosis of the hand--a case study]

Heavy physical work load is a known determinant of osteoarthritis of the hip, which may account for the high risk observed among farmers. On the other hand, the data on influence of heavy manual work in the pathogenesis of hand osteoarthritis are still controversial. We examined 25 retired farm laborers who strenuously worked for more than 50 years. The investigation included a history of professional activity, clinical and radiological examination of the hands, hips and knees, MRI of hand and laboratory evaluation of 4 participants. Interestingly, the farm laborers with osteoarthritis of the hands, hardly complained. In many of the proximal interphalangeal joints, a discrepancy was observed between the clinical hypertrophic changes and the radiological osteoarthritis which was weak or absent. This difference was less pronounced in the distal interphalangeal joints. Furthermore the distribution pattern of the osteoarthritis of the hand was striking with an over-proportional involvement of the metacarpophalangeal joints and less pronounced of the intercarpal joints. Most often both hands have been affected and the typical localization of the metacarphophalangeal joint osteoarthritis was the first, second and third finger. In all but one participant we found at least unilateral osteoarthritis of the hip and compared to the hands, complaints were more severe. Our findings support the hypothesis that the distribution of osteoarthritis in the hand is affected by lifelong farming. As shown by the data on proximal interphalangeal joints, the periarticular tissue can adapt to the mechanical load in the strength grip.