Recommendations for the organization of the teleconsultation service in a telestroke network

Telestroke networks aim to improve acute stroke care within their catchment area. Through a teleconsultation service, the network centers provide support to network hospitals that lack continuous neurological expertise for acute stroke management decisions. Although the importance of telemedical treatment in stroke care is steadily increasing, so far no standards exist for the organization of the teleconsultation service in networks.To ensure a high-level of quality for all processes and measures concerning telemedical stroke treatment, the commission for telemedical stroke care of the German Stroke Society (Deutsche Schlaganfall-Gesellschaft, DSG) created the following recommendations on how to organize a teleconsultation service within a telestroke network. The recommendations are the result of an adjustment process between the authors and include guidance on requirements, qualifications, processes and quality management within the teleconsultation service.

Effect of Low-Frequency Renal Nerve Stimulation on Renal Glucose Release during Normoglycemia and a Hypoglycemic Clamp in Pigs

Previously, we demonstrated that renal denervation in pigs reduces renal glucose release during a hypoglycemic episode. In this study we set out to examine changes in side-dependent renal net glucose release (SGN) through unilateral low-frequency stimulation (LFS) of the renal plexus with a pulse generator (2-5 Hz) during normoglycemia (60 min) and insulin-induced hypoglycemia ≤3.5 mmol/L (75 min) in seven pigs. The jugular vein, carotid artery, renal artery and vein, and both ureters were catheterized for measurement purposes, blood pressure management, and drug and fluid infusions. Para-aminohippurate (PAH) and inulin infusions were used to determine side-dependent renal plasma flow (SRP) and glomerular filtration rate (GFR). In a linear mixed model, LFS caused no change in SRP but decreased sodium excretion (p < 0.0001), as well as decreasing GFR during hypoglycemia (p = 0.0176). In a linear mixed model, only hypoglycemic conditions exerted significant effects on SGN (p = 0.001), whereas LFS did not. In a Wilcoxon signed rank exact test, LFS significantly increased SGN (p = 0.03125) and decreased sodium excretion (p = 0.0017) and urinary flow rate (p = 0.0129) when only considering the first instance LFS followed a preceding period of non-stimulation during normoglycemia. To conclude, this study represents, to our knowledge, the first description of an induction of renal gluconeogenesis by LFS.

Development and implementation of a student tumor board as a teaching format for medical students

PURPOSE

Tumor boards serve as established platforms for interdisciplinary expert discussions and therapeutic recommendations tailored to individual patient characteristics. Despite their significance, medical students often lack exposure to such interdisciplinary discussions as tumor boards are currently not integrated into medical curricula. To address this, we aimed to enhance future physicians' interdisciplinary communication skills and subject-specific knowledge by introducing an interactive series of five linked tumor board seminars within the domain of neuro-oncology.

METHODS

We developed a neuro-oncological student tumor board using a flipped-classroom format. The primary objectives of this case-centered approach included fostering an understanding of the tumor board process, active participation in multidisciplinary case discussions, honing appropriate communication strategies, and creating personalized therapy plans that consider inputs from all relevant disciplines, individual patient factors, and ethical considerations. To gauge the effectiveness of the seminar series, we administered structured pre- and post-course questionnaires.

RESULTS

Fourteen medical students in third to fifth year participated in the pilot series. Despite its organizational complexity, the interdisciplinary seminars were feasible. Students demonstrated significant growth in competence, aligned with predefined learning objectives. Notably, they appreciated the supportive learning environment and interactive teaching format, which kindled their interest in interdisciplinary oncology.

CONCLUSION

Active participation in a student tumor board can empower students to tackle the diverse challenges of caring for cancer patients within an interdisciplinary team during the early stages of their careers. The student tumor board represents an innovative, learner-centered approach to teach interdisciplinary cancer treatment, communication strategies, and ethical aspects of medical practice.

Renal Glucose Release after Unilateral Renal Denervation during a Hypoglycemic Clamp in Pigs with an Altered Hypothalamic Pituitary Adrenal Axis after Late-Gestational Dexamethasone Injection

Previously, we demonstrated in pigs that renal denervation halves glucose release during hypoglycaemia and that a prenatal dexamethasone injection caused increased ACTH and cortisol concentrations as markers of a heightened hypothalamic pituitary adrenal axis (HPAA) during hypoglycaemia. In this study, we investigated the influence of an altered HPAA on renal glucose release during hypoglycaemia. Pigs whose mothers had received two late-gestational dexamethasone injections were subjected to a 75 min hyperinsulinaemic-hypoglycaemic clamp (<3 mmol/L) after unilateral surgical denervation. Para-aminohippurate (PAH) clearance, inulin, sodium excretion and arterio-venous blood glucose difference were measured every fifteen minutes. The statistical analysis was performed with a Wilcoxon signed-rank test. PAH, inulin, the calculated glomerular filtration rate and plasma flow did not change through renal denervation. Urinary sodium excretion increased significantly (p = 0.019). Side-dependent renal net glucose release (SGN) decreased by 25 ± 23% (p = 0.004). At 25 percent, the SGN decrease was only half of that observed in non-HPAA-altered animals in our prior investigation. The current findings may suggest that specimens with an elevated HPAA undergo long-term adaptations to maintain glucose homeostasis. Nonetheless, the decrease in SGN warrants further investigations and potentially caution in performing renal denervation in certain patient groups, such as diabetics at risk of hypoglycaemia.

The Effect of Endovascular Thrombectomy Studies on the Decision to Transfer Patients in a Telestroke Network

Background/Introduction: In 2015, five high-quality trials demonstrated the effectiveness of endovascular thrombectomy for certain patients. Patient selection for transfer to a hub hospital is mostly focused on the patient's eligibility for a potential thrombectomy. However, it remains challenging to correctly select those patients with the highest probability of undergoing a thrombectomy. Materials and Methods: In this study, we investigated which factors promote or impede the transfer of patients and whether the impact of these factors has changed since the publication of the five randomized thrombectomy studies in 2015. We analyzed 12,048 cases of telestroke consultation from the stroke telemedicine network in Thuringia (SATELIT) and compared the decision-making process related to patient transfer based on consultations that occurred before and after 2015. Results: In both time intervals, we found that the patient's age and the identification of a proximal vessel occlusion independently influenced the decision to transfer a patient. The age factor remained unchanged over time. A known proximal intracranial vessel occlusion had a strong positive influence on the decision to transfer patients. Discussion: The decision of whether to transfer a patient is currently focused on the identification of intracranial vessel occlusion. However, the age of the patient remains an unchanged but important factor that might be overemphasized. The time elapsed from symptom onset to consultation was not found to have an independent influence on the decision-making process, so it might be underemphasized. Conclusions: The decision-making process to transfer a patient within our telestroke network has been strongly affected by the publication of the endovascular thrombectomy studies, but those studies are not solely optimized for this aim.

Evolution from Ferromagnetism to Antiferromagnetism in Yb(Rh_{1-x}Co_{x})_{2}Si_{2}

Yb(Rh_{1-x}Co_{x})_{2}Si_{2} is a model system to address two challenging problems in the field of strongly correlated electron systems. The first is the intriguing competition between ferromagnetic (FM) and antiferromagnetic (AFM) order when approaching a magnetic quantum critical point (QCP). The second is the occurrence of magnetic order along a very hard crystalline electric field (CEF) direction, i.e., along the one with the smallest available magnetic moment. Here, we present a detailed study of the evolution of the magnetic order in this system from a FM state with moments along the very hard c direction at x=0.27 towards the yet unknown magnetic state at x=0. We first observe a transition towards an AFM canted state with decreasing x and then to a pure AFM state. This confirms that the QCP in YbRh_{2}Si_{2} is AFM, but the phase diagram is very similar to those observed in some inherently FM systems like NbFe_{2} and CeRuPO, which suggests that the basic underlying instability might be FM. Despite the huge CEF anisotropy the ordered moment retains a component along the c axis also in the AFM state. The huge CEF anisotropy in Yb(Rh_{1-x}Co_{x})_{2}Si_{2} excludes that this hard-axis ordering originates from a competing exchange anisotropy as often proposed for other heavy-fermion systems. Instead, it points to an order-by-disorder based mechanism.

Motor-cognitive dual-task performance: effects of a concurrent motor task on distinct components of visual processing capacity

Dual tasking, or the simultaneous execution of two continuous tasks, is frequently associated with a performance decline that can be explained within a capacity sharing framework. In this study, we assessed the effects of a concurrent motor task on the efficiency of visual information uptake based on the 'theory of visual attention' (TVA). TVA provides parameter estimates reflecting distinct components of visual processing capacity: perceptual threshold, visual processing speed, and visual short-term memory (VSTM) storage capacity. Moreover, goodness-of-fit values and bootstrapping estimates were derived to test whether the TVA-model is validly applicable also under dual task conditions, and whether the robustness of parameter estimates is comparable in single- and dual-task conditions. 24 subjects of middle to higher age performed a continuous tapping task, and a visual processing task (whole report of briefly presented letter arrays) under both single- and dual-task conditions. Results suggest a decline of both visual processing capacity and VSTM storage capacity under dual-task conditions, while the perceptual threshold remained unaffected by a concurrent motor task. In addition, goodness-of-fit values and bootstrapping estimates support the notion that participants processed the visual task in a qualitatively comparable, although quantitatively less efficient way under dual-task conditions. The results support a capacity sharing account of motor-cognitive dual tasking and suggest that even performing a relatively simple motor task relies on central attentional capacity that is necessary for efficient visual information uptake.

Doped YbRh2Si2: not only ferromagnetic correlations but ferromagnetic order

YbRh2Si2 is a prototypical system for studying unconventional antiferromagnetic quantum criticality. However, ferromagnetic correlations are present which can be enhanced via isoelectronic cobalt substitution for rhodium in Yb(Rh(1-x)Co(x))2Si2. So far, the magnetic order with increasing x was believed to remain antiferromagnetic. Here, we present the discovery of ferromagnetism for x = 0.27 below T(C) = 1.30  K in single crystalline samples. Unexpectedly, ordering occurs along the c axis, the hard crystalline electric field direction, where the g factor is an order of magnitude smaller than in the basal plane. Although the spontaneous magnetization is only 0.1 μB/Yb it corresponds to the full expected saturation moment along c taking into account partial Kondo screening.

Magnetism, f-electron localization and superconductivity in 122-type heavy-fermion metals

Both CeCu2Si2 and YbRh2Si2 crystallize in the tetragonal ThCr2Si2 crystal structure. Recent neutron-scattering results on normal-state CeCu2Si2 reveal a slowing down of the quasielastic response which complies with the scaling expected for a quantum critical point (QCP) of itinerant, i.e., three-dimensional spin-density-wave (SDW), type. This interpretation is in full agreement with the non-Fermi-liquid behavior observed in transport and thermodynamic measurements. The momentum dependence of the magnetic excitation spectrum reveals two branches of an overdamped dispersive mode whose coupling to the heavy charge carriers is strongly retarded. These overdamped spin fluctuations are considered to be the driving force for superconductivity in CeCu2Si2 (Tc = 600 mK). The weak antiferromagnet YbRh2Si2 (TN = 70 mK) exhibits a magnetic-field-induced QCP at BN = 0.06 T (B⊥c). There is no indication of superconductivity down to T = 10 mK. The magnetic QCP appears to concur with a breakdown of the Kondo effect. Doping-induced variations of the average unit-cell volume result in a detachment of the magnetic and electronic instabilities. A comparison of the properties of these isostructural compounds suggests that 3D SDW QCPs are favorable for unconventional superconductivity. The question whether a Kondo-breakdown QCP may also give rise to superconductivity, however, remains to be clarified.

In vivo 1 H magnetic resonance spectroscopy of rat brain after valproate administration

Previous studies have shown that valproate is detectable in vitro by 1H magnetic resonance spectroscopy (MRS) at 1.5 T, whereas in patients on valproate monotherapy, no significant dose-dependent valproate signal could be seen. To investigate whether an increased signal-to-noise ratio as provided by higher valproate doses and increased magnetic field strength would enable detection of valproate in vivo, six Wistar rats were examined using volume-selective 1H MRS at 2.34 T. The spectra were analyzed by fitting a linear superposition of the basis spectra of valproate, brain metabolites, and simulated lipid signals. The analysis revealed no significant signal contributions after valproate administration of up to 330 mg/kg body weight. To analyze how underlying mechanisms, such as potential drug interactions with macromolecules, may affect the valproate signal, additional in vitro spectra of valproate were measured before and after adding albumin. The spectra exhibited a strong decrease of the valproate signal with increasing albumin concentration. The results support the hypothesis that in vivo valproate is bound to a high degree to macromolecules and will therefore not be detectable by 1H MRS.