A functional motor unit in the culture dish : co-culture of spinal cord explants and muscle cells

Human primary muscle cells cultured aneurally in monolayer rarely contract spontaneously because, in the absence of a nerve component, cell differentiation is limited and motor neuron stimulation is missing(1). These limitations hamper the in vitro study of many neuromuscular diseases in cultured muscle cells. Importantly, the experimental constraints of monolayered, cultured muscle cells can be overcome by functional innervation of myofibers with spinal cord explants in co-cultures. Here, we show the different steps required to achieve an efficient, proper innervation of human primary muscle cells, leading to complete differentiation and fiber contraction according to the method developed by Askanas(2). To do so, muscle cells are co-cultured with spinal cord explants of rat embryos at ED 13.5, with the dorsal root ganglia still attached to the spinal cord slices. After a few days, the muscle fibers start to contract and eventually become cross-striated through innervation by functional neurites projecting from the spinal cord explants that connecting to the muscle cells. This structure can be maintained for many months, simply by regular exchange of the culture medium. The applications of this invaluable tool are numerous, as it represents a functional model for multidisciplinary analyses of human muscle development and innervation. In fact, a complete de novo neuromuscular junction installation occurs in a culture dish, allowing an easy measurement of many parameters at each step, in a fundamental and physiological context. Just to cite a few examples, genomic and/or proteomic studies can be performed directly on the co-cultures. Furthermore, pre- and post-synaptic effects can be specifically and separately assessed at the neuromuscular junction, because both components come from different species, rat and human, respectively. The nerve-muscle co-culture can also be performed with human muscle cells isolated from patients suffering from muscle or neuromuscu diseases(3), and thus can be used as a screening tool for candidate drugs. Finally, no special equipment but a regular BSL2 facility is needed to reproduce a functional motor unit in a culture dish. This method thus is valuable for both the muscle as well as the neuromuscular research communities for physiological and mechanistic studies of neuromuscular function, in a normal and disease context

Optical photothermal infrared spectroscopy with simultaneously acquired Raman spectroscopy for two-dimensional microplastic identification

In recent years, vibrational spectroscopic techniques based on Fourier transform infrared (FTIR) or Raman microspectroscopy have been suggested to fulfill the unmet need for microplastic particle detection and identification. Inter-system comparison of spectra from reference polymers enables assessing the reproducibility between instruments and advantages of emerging quantum cascade laser-based optical photothermal infrared (O-PTIR) spectroscopy. In our work, IR and Raman spectra of nine plastics, namely polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, silicone, polylactide acid and polymethylmethacrylate were simultaneously acquired using an O-PTIR microscope in non-contact, reflection mode. Comprehensive band assignments were presented. We determined the agreement of O-PTIR with standalone attenuated total reflection FTIR and Raman spectrometers based on the hit quality index (HQI) and introduced a two-dimensional identification (2D-HQI) approach using both Raman- and IR-HQIs. Finally, microplastic particles were prepared as test samples from known materials by wet grinding, O-PTIR data were collected and subjected to the 2D-HQI identification approach. We concluded that this framework offers improved material identification of microplastic particles in environmental, nutritious and biological matrices

Structured immune work-up in healthy children with a first episode of severe bacterial infection: a 7-year single-center study

Background: Severe bacterial infections (SBI) in otherwise healthy children are rare and may represent an underlying impairment of the immune system including primary immunodeficiency (PID). However, it is unclear if and how children should be assessed. Methods: We retrospectively analyzed data from hospital records of previously healthy children aged 3 days to 18 years with SBI including pleuropneumonia, meningitis, and/or sepsis. Patients were diagnosed or immunologically followed-up between 2013/01/01 and 2020/03/31. Results: Out of 432 children with SBI, 360 children could be analyzed. Follow-up data were available for 265 (74%) children, of whom 244 children (92%) had immunological testing. Laboratory abnormalities were found in 51 of 244 patients (21%), with 3 deaths (1%). There were 14 (6%) children with immunodeficiency considered clinically relevant (3 complement deficiencies, 1 autoimmune neutropenia, 10 humoral immunodeficiencies) and 27 (11%) with milder humoral abnormalities or findings suggestive of delayed adaptive immune maturation. Conclusions: A substantial proportion of children with SBI may benefit from routine immunological testing, revealing (potentially) clinically relevant impaired immune function in 6-17% of children. The identification of immune abnormalities allows for specific counselling of families and optimization of preventive measures such as booster vaccinations to avoid future SBI episodes

Passive intrinsic-linewidth narrowing of ultraviolet extended-cavity diode laser by weak optical feedback

We present a simple method for narrowing the intrinsic Lorentzian linewidth of a commercial ultraviolet grating extended-cavity diode laser (TOPTICA DL Pro) using weak optical feedback from a long external cavity. We achieve a suppression in frequency noise spectral density of 20 dB measured at frequencies around 1 MHz, corresponding to the narrowing of the intrinsic Lorentzian linewidth from 200 kHz to 2 kHz. The system is suitable for experiments requiring a tunable ultraviolet laser with narrow linewidth and low high-frequency noise, such as precision spectroscopy, optical clocks, and quantum information science experiments.Comment: 8 pages, 3 figure

On orthogonal projections for dimension reduction and applications in augmented target loss functions for learning problems

The use of orthogonal projections on high-dimensional input and target data in learning frameworks is studied. First, we investigate the relations between two standard objectives in dimension reduction, preservation of variance and of pairwise relative distances. Investigations of their asymptotic correlation as well as numerical experiments show that a projection does usually not satisfy both objectives at once. In a standard classification problem we determine projections on the input data that balance the objectives and compare subsequent results. Next, we extend our application of orthogonal projections to deep learning tasks and introduce a general framework of augmented target loss functions. These loss functions integrate additional information via transformations and projections of the target data. In two supervised learning problems, clinical image segmentation and music information classification, the application of our proposed augmented target loss functions increase the accuracy

The impact of fasciotomy on inpatient outcomes in lower leg fracture management.

BACKGROUND While lower extremity fractures are common injuries, concomitant compartment syndrome can lead to significant implications and surgical release (fasciotomy) is essential. The aim of this study was to identify potential predictors of compartment release and risk factors related to complications. Using a large nationwide cohort, this study compared patients suffering from lower extremity fractures with and without compartment syndrome during their primary in-hospital stay following trauma. METHODS A retrospective analysis was conducted using the prospective surgical registry of the working group for quality assurance in surgery in Switzerland, which collects data from nearly 85% of all institutions involved in trauma surgery. Inclusion criteria Patients who underwent surgical treatment for tibia and/or fibula fractures between January 2012 and December 2022 were included in the study. Statistics Statistical analysis was performed using Chi-square, Fisher's exact test, and t test. Furthermore, a regression analysis was conducted to determine the independent risk factors for fasciotomy and related complications. In the present study, a p value less than 0.001 was determined to indicate statistical significance due to the large sample size. RESULTS The total number of cases analyzed was 1784, of which 98 underwent fasciotomies and 1686 did not undergo the procedure. Patients with fasciotomies were identified as significantly younger (39 vs. 43 years old) and mostly male (85% vs. 64%), with a significantly higher American Society of Anesthesiologists (ASA) score (ASA III 10% vs. 6%) and significantly more comorbidities (30% vs. 20%). These patients had significantly longer duration of surgeries (136 vs. 102 min). Furthermore, the total number of surgical interventions, the rate of antibiotic treatment, and related complications were significantly higher in the fasciotomy group. Sex, age, comorbidities, and fracture type (both bones fractured) were identified as relevant predictors for fasciotomy, while ASA class was the only predictor for in-hospital complications. Outcomes Patients who underwent fasciotomy had a significantly longer hospital stay (18 vs. 9 days) and a higher complication rate (42% vs. 6%) compared to those without fasciotomy. While fasciotomy may have played a role, other factors such as variations in patient characteristics and injury mechanisms may also contribute. Additionally, in-house mortality was found to be 0.17%, with no patient death recorded for the fasciotomy group. CONCLUSIONS Fasciotomy is vital. The knowledge about the further course is, however, helpful in resource allocation. We found significant differences between patients with and without fasciotomy in terms of age, sex, complication rate, length of stay, comorbidities, duration of operations, and use of antibiotics during their primary in-hospital stay. While the severity of the underlying trauma could not be modulated, awareness of the most relevant predictors for fasciotomy and related complications might help mitigate severe consequences and avoid adverse outcomes

Matching Allocation Problems with Endogenous Information Acquisition

The paper introduces the assumption of costly information acquisition to the theory of mechanism design for matching allocation problems. It is shown that the assumption of endogenous information acquisition greatly changes some of the cherished results in that theory: in particular, the first-best might not be implementable. Moreover, it might not even be possible to implement the second-best through trade. In addition, the paper highlights the use of randomness in setting incentives for efficient learning. The trade-offs among simultaneous and sequential learning and among efficient learning and efficient allocations are discussed

Structural Differences Between Healthy Subjects and Patients With Schizophrenia or Schizoaffective Disorder: A Graph and Control Theoretical Perspective

The coordinated dynamic interactions of large-scale brain circuits and networks have been associated with cognitive functions and behavior. Recent advances in network neuroscience have suggested that the anatomical organization of such networks puts fundamental constraints on the dynamical landscape of brain activity, i.e., the different states, or patterns of regional activation, and transition between states the brain can display. Specifically, it has been shown that densely connected, central regions control the transition between states that are “easily” reachable (in terms of expended energy), whereas weakly connected areas control transitions to states that are hard-to-reach. Changes in large-scale brain activity have been hypothesized to underlie many neurological and psychiatric disorders. Evidence has emerged that large-scale dysconnectivity might play a crucial role in the pathophysiology of schizophrenia, especially regarding cognitive symptoms. Therefore, an analysis of graph and control theoretic measures of large-scale brain connectivity in patients offers to give insight into the emergence of cognitive disturbances in the disorder. To investigate these potential differences between patients with schizophrenia (SCZ), patients with schizoaffective disorder (SCZaff) and matched healthy controls (HC), we used structural MRI data to assess the microstructural organization of white matter. We first calculate seven graph measures of integration, segregation, centrality and resilience and test for group differences. Second, we extend our analysis beyond these traditional measures and employ a simplified noise-free linear discrete-time and time-invariant network model to calculate two complementary measures of controllability. Average controllability, which identifies brain areas that can guide brain activity into different, easily reachable states with little input energy and modal controllability, which characterizes regions that can push the brain into difficult-to-reach states, i.e., states that require substantial input energy. We identified differences in standard network and controllability measures for both patient groups compared to HCs. We found a strong reduction of betweenness centrality for both patient groups and a strong reduction in average controllability for the SCZ group again in comparison to the HC group. Our findings of network level deficits might help to explain the many cognitive deficits associated with these disorders.Peer reviewe