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26 result(s) for "Nau, Carla"
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Workforce strategies during the first wave of the COVID-19 pandemic: a retrospective online survey at intensive care units in Germany
Background As the COVID-19 pandemic swept across the globe at the beginning of 2020, healthcare systems were forced to rapidly adapt and expand to meet the sudden surge in demand for intensive care services. This study is the first systematic analysis of the strategies employed by German hospitals to recruit personnel and expand bed capacities during the first wave of the pandemic, and to evaluate the effectiveness of those recruitment measures. Methods 152 German hospitals with intensive care capacities were selected and invited to participate in an online-based retrospective survey. Factors like the geographic distribution, individual COVID burden and level of care were considered for inclusion in the sample. The data were analyzed descriptively. Results A total of 41 hospitals participated in the survey. The additional demand for intensive care beds was met primarily by activating intensive care beds that were previously considered as non-operational in existing intensive care units (81% of respondents) and by upgrading recovery rooms (73%). The physician staffing requirements were met at approximately 75%, while the nursing staffing requirements were only met by about 45%. Staffing needs were met through reallocations/transfers (85%), staff recruitment from parental leave or retirement (49%), increased hours worked by internal staff (49%), new staff hiring (44%) and increased use of temporary staff (32%). Staff reallocations/transfers to critical care within a hospital were rated as the most effective measure. In this context, specialized personnel mostly from anesthesiology departments were appointed to intensive care medicine. Conclusions Despite multiple recruitment efforts, the pandemic has exacerbated the nursing staff shortage. The reallocation of existing staff within hospitals was a key element in covering the staffing needs. However, additional measures and efforts are required in order to ensure that critically ill patients can be cared for without compromise. The results of this study may have important implications for healthcare providers and policymakers, offering an evidence-based foundation for responding to future public health emergencies with agility, efficiency, and success.
Activation of TRPA1 by Membrane Permeable Local Anesthetics
Background: Low concentrations of local anesthetics (LAs) suppress cellular excitability by inhibiting voltage-gated Na+ channels. In contrast, LAs at high concentrations can be excitatory and neurotoxic. We recently demonstrated that LA-evoked activation of sensory neurons is mediated by the capsaicin receptor TRPV1, and, to a lesser extent by the irritant receptor TRPA1. LA-induced activation and sensitization of TRPV1 involves a domain that is similar, but not identical to the vanilloid-binding domain. Additionally, activation of TRPV1 by LAs involves PLC and PI(4,5)P2-signalling. In the present study we aimed to characterize essential structural determinants for LA-evoked activation of TRPA1. Results: Recombinant rodent and human TRPA1 were expressed in HEK293t cells and investigated by means of whole-cell patch clamp recordings. The LA lidocaine activates TRPA1 in a concentration-dependent manner. The membrane impermeable lidocaine-derivative QX-314 is inactive when applied extracellularly. Lidocaine-activated TRPA1-currents are blocked by the TRPA1-antagonist HC-030031. Lidocaine is also an inhibitor of TRPA1, an effect that is more obvious in rodent than in human TRPA1. This species-specific difference is linked to the pore region (transmembrane domain 5 and 6) as described for activation of TRPA1 by menthol. Unlike menthol-sensitivity however, lidocaine-sensitivity is not similarly determined by serine- and threonine-residues within TM5. Instead, intracellular cysteine residues known to be covalently bound by reactive TRPA1-agonists seem to mediate activation of TRPA1 by LAs. Conclusions: The structural determinants involved in activation of TRPA1 by LAs are disparate from those involved in activation by menthol or those involved in activation of TRPV1 by LAs.
Electrophysiological Properties of Induced Pluripotent Stem Cell-Derived Midbrain Dopaminergic Neurons Correlate With Expression of Tyrosine Hydroxylase
Induced pluripotent stem cell (iPSC)-based generation of tyrosine hydroxylase-positive (TH+) dopaminergic neurons (DNs) is a powerful method for creating patient-specific in vitro models to elucidate mechanisms underlying Parkinson’s disease (PD) at the cellular and molecular level and to perform drug screening. However, currently available differentiation paradigms result in highly heterogeneous cell populations, often yielding a disappointing fraction (<50%) of the PD-relevant TH+ DNs. To facilitate the targeted analysis of this cell population and to characterize their electrophysiological properties, we employed CRISPR/Cas9 technology and generated an mCherry-based human TH reporter iPSC line. Subsequently, reporter iPSCs were subjected to dopaminergic differentiation using either a ‘floor plate protocol’ generating DNs directly from iPSCs or an alternative method involving iPSC-derived neuronal precursors (NPC-derived DNs). To identify the strategy with the highest conversion efficiency to mature neurons, both cultures were examined for a period of eight weeks after triggering neuronal differentiation by means of immunochemistry and single-cell electrophysiology. We confirmed that mCherry expression correlated with the expression of endogenous TH and that genetic editing did neither affect the differentiation process nor the endogenous TH expression in iPSC- and NPC-derived DNs. Although both cultures yielded identical proportions of TH+ cells (30%), whole-cell patch-clamp experiments revealed that iPSC-derived DNs gave rise to larger currents mediated by voltage-gated sodium and potassium channels, showed a higher degree of synaptic activity, and fired trains of mature spontaneous action potentials more frequently compared to NPC-derived DNs already after two weeks in differentiation. Moreover, spontaneous action potential firing was more frequently detected in TH+ neurons compared to the TH cells, providing direct evidence that these two neuronal subpopulations exhibit different intrinsic electrophysiological properties. In summary, the data reveal substantial differences in the electrophysiological properties of iPSC-derived TH+ and TH neuronal cell populations and that the ‘floor plate protocol’ is particularly efficient in generating electrophysiologically mature TH+ DNs, which are the most vulnerable neuronal subtype in PD.
The vanilloid receptor TRPV1 is activated and sensitized by local anesthetics in rodent sensory neurons
Local anesthetics (LAs) block the generation and propagation of action potentials by interacting with specific sites of voltage-gated Na(+) channels. LAs can also excite sensory neurons and be neurotoxic through mechanisms that are as yet undefined. Nonspecific cation channels of the transient receptor potential (TRP) channel family that are predominantly expressed by nociceptive sensory neurons render these neurons sensitive to a variety of insults. Here we demonstrated that the LA lidocaine activated TRP channel family receptors TRPV1 and, to a lesser extent, TRPA1 in rodent dorsal root ganglion sensory neurons as well as in HEK293t cells expressing TRPV1 or TRPA1. Lidocaine also induced a TRPV1-dependent release of calcitonin gene-related peptide (CGRP) from isolated skin and peripheral nerve. Lidocaine sensitivity of TRPV1 required segments of the putative vanilloid-binding domain within and adjacent to transmembrane domain 3, was diminished under phosphatidylinositol 4,5-bisphosphate depletion, and was abrogated by a point mutation at residue R701 in the proximal C-terminal TRP domain. These data identify TRPV1 and TRPA1 as putative key elements of LA-induced nociceptor excitation. This effect is sufficient to release CGRP, a key component of neurogenic inflammation, and warrants investigation into the role of TRPV1 and TRPA1 in LA-induced neurotoxicity.
Isolation and transfection of myenteric neurons from mice for patch-clamp applications
The enteric nervous system (ENS) is a complex neuronal network organized in ganglionated plexuses that extend along the entire length of the gastrointestinal tract. Largely independent of the central nervous system, the ENS coordinates motility and peristalsis of the digestive tract, regulates secretion and absorption, and is involved in immunological processes. Electrophysiological methods such as the patch-clamp technique are particularly suitable to study the function of neurons as well as the biophysical parameters of the underlying ion channels under both physiological and pathophysiological conditions. However, application of the patch-clamp method to ENS neurons remained difficult because they are embedded in substantial tissue layers that limit access to and targeted manipulation of these cells. Here, we present a robust step-by-step protocol that involves isolation of ENS neurons from adult mice, culturing of the cells, their transfection with plasmid DNA, and subsequent electrophysiological characterization of individual neurons in current-clamp and voltage-clamp recordings. With this protocol, ENS neurons can be prepared, transfected, and electrophysiologically characterized within 72 h. Using isolated ENS neurons, we demonstrate the feasibility of the approach by functional overexpression of recombinant voltage-gated Na V 1.9 mutant channels associated with hereditary sensory and autonomic neuropathy type 7 (HSAN-7), a disorder characterized by congenital analgesia and severe constipation that can require parenteral nutrition. Although our focus is on the electrophysiological evaluation of isolated ENS neurons, the presented methodology is also useful to analyze molecules other than sodium channels or to apply alternative downstream assays including calcium imaging, proteomic and nucleic acid approaches, or immunochemistry.
Telemedicine in adult intensive care: A systematic review of patient-relevant outcomes and methodological considerations
Given the growing challenges of healthcare, including an aging population and increasing shortages of specialized intensive care staff, this systematic review investigates the efficacy of telemedicine in intensive care compared to standard of care (SoC) or any other type or mode of telemedicine on patient-relevant outcomes for adult intensive care unit (ICU) patients. This systematic review follows Cochrane's methodological standards. Comprehensive searches for any controlled clinical studies were conducted in MEDLINE, Scopus, CINAHL, and CENTRAL (up to 18 April 2024, and an updated search for randomized controlled trials (RCTs) up to 29 September 2025). Twenty-six studies comparing telemedicine in intensive care to SoC with approximately 2,164,508 analysed patients were identified, including data from one cluster RCT (cRCT), two stepped-wedge cluster RCTs (sw-cRCTs), and 23 non-randomized studies of interventions (NRSIs). No other comparisons were identified. Due to high clinical and methodological heterogeneity among studies, no meta-analysis was conducted. For ICU mortality, one cRCT (15,230 patients) and two sw-cRCTs (5,915 patients) showed heterogeneous results: two found no evidence for a difference, while one favoured SoC (very low-certainty). One sw-cRCT (1,462 patients) reporting overall mortality at 180 days suggested no evidence for a difference between groups (very low-certainty). Data from one cRCT (15,230 patients) and one sw-cRCT (1,462 patients) on ICU length of stay (LOS) showed no evidence for a difference between groups (moderate- and very low-certainty). Quality of life from one sw-cRCT (786 patients) indicated no evidence for a difference (very low-certainty). Six NRSIs reported adjusted data on ICU mortality, two on overall mortality, and three on ICU LOS, with heterogeneous results. High risk of bias and substantial heterogeneity limited the certainty, emphasizing the need for robust, patient-centered research in clinical studies to define telemedicine's role in intensive care and optimize its implementation. Future studies should particularly ensure transparent and comprehensive reporting.
Peripheral temperature dysregulation associated with functionally altered NaV1.8 channels
The voltage-gated sodium channel NaV1.8 is prominently expressed in the soma and axons of small-caliber sensory neurons, and pathogenic variants of the corresponding gene SCN10A are associated with peripheral pain and autonomic dysfunction. While most disease-associated SCN10A variants confer gain-of-function properties to NaV1.8, resulting in hyperexcitability of sensory neurons, a few affect afferent excitability through a loss-of-function mechanism. Using whole-exome sequencing, we here identify a rare heterozygous SCN10A missense variant resulting in alteration p.V1287I in NaV1.8 in a patient with a 15-year history of progressively worsening temperature dysregulation in the distal extremities, particularly in the feet. Further symptoms include increasingly intensifying tingling and numbness in the fingers and increased sweating. To assess the impact of p.V1287I on channel function, we performed voltage-clamp recordings demonstrating that the alteration confers loss- and gain-of-function characteristics to NaV1.8 characterized by a right-shifted voltage dependence of channel activation and inactivation. Current-clamp recordings from transfected mouse dorsal root ganglion neurons further revealed that NaV1.8-V1287I channels broaden the action potentials of sensory neurons and increase their firing rates in response to depolarizing current stimulations, indicating a gain-of-function mechanism of the variant at the cellular level in a heterozygous setting. The data support the hypothesis that the properties of NaV1.8 p.V1287I are causative for the patient’s symptoms and that nonpainful peripheral paresthesias should be considered part of the clinical spectrum of NaV1.8-associated disorders.
Methylglyoxal modification of Nav1.8 facilitates nociceptive neuron firing and causes hyperalgesia in diabetic neuropathy
Glucose and its metabolic derivatives are increased the plasma of patients with diabetes. Peter Nawroth and colleagues demonstrate that one such metabolite, methylglyoxal, is increased in patients with painful diabetic neuropathy, and find that it acts by modifying the excitability characteristics of a sodium channel protein. This study establishes a mechanism for metabolic hyperalgesia based on the glycolytic metabolite methylglyoxal. We found that concentrations of plasma methylglyoxal above 600 nM discriminate between diabetes-affected individuals with pain and those without pain. Methylglyoxal depolarizes sensory neurons and induces post-translational modifications of the voltage-gated sodium channel Na v 1.8, which are associated with increased electrical excitability and facilitated firing of nociceptive neurons, whereas it promotes the slow inactivation of Na v 1.7. In mice, treatment with methylglyoxal reduces nerve conduction velocity, facilitates neurosecretion of calcitonin gene-related peptide, increases cyclooxygenase-2 (COX-2) expression and evokes thermal and mechanical hyperalgesia. This hyperalgesia is reflected by increased blood flow in brain regions that are involved in pain processing. We also found similar changes in streptozotocin-induced and genetic mouse models of diabetes but not in Na v 1.8 knockout ( Scn10 −/− ) mice. Several strategies that include a methylglyoxal scavenger are effective in reducing methylglyoxal- and diabetes-induced hyperalgesia. This previously undescribed concept of metabolically driven hyperalgesia provides a new basis for the design of therapeutic interventions for painful diabetic neuropathy.
Sensory neuron sodium channel Nav1.8 is essential for pain at low temperatures
Sensory acuity deteriorates at cold temperatures, but pain perception persists and cold stimuli themselves can be painful. A voltage-gated sodium channel, Na v 1.8, is implicated in this perception. Unlike other channels, Na v 1.8 does not inactivate at lower temperatures and its currents are actually larger in colder conditions Sensory acuity and motor dexterity deteriorate when human limbs cool down, but pain perception persists and cold-induced pain can become excruciating 1 . Evolutionary pressure to enforce protective behaviour requires that damage-sensing neurons (nociceptors) continue to function at low temperatures. Here we show that this goal is achieved by endowing superficial endings of slowly conducting nociceptive fibres with the tetrodotoxin-resistant voltage-gated sodium channel (VGSC) Na v 1.8 (ref. 2 ). This channel is essential for sustained excitability of nociceptors when the skin is cooled. We show that cooling excitable membranes progressively enhances the voltage-dependent slow inactivation of tetrodotoxin-sensitive VGSCs. In contrast, the inactivation properties of Na v 1.8 are entirely cold-resistant. Moreover, low temperatures decrease the activation threshold of the sodium currents and increase the membrane resistance, augmenting the voltage change caused by any membrane current. Thus, in the cold, Na v 1.8 remains available as the sole electrical impulse generator in nociceptors that transmits nociceptive information to the central nervous system. Consistent with this concept is the observation that Na v 1.8-null mutant mice 3 show negligible responses to noxious cold and mechanical stimulation at low temperatures. Our data present strong evidence for a specialized role of Na v 1.8 in nociceptors as the critical molecule for the perception of cold pain and pain in the cold.
Prehabilitation of elderly frail or pre-frail patients prior to elective surgery (PRAEP-GO): study protocol for a randomized, controlled, outcome assessor-blinded trial
Background Frailty is expressed by a reduction in physical capacity, mobility, muscle strength, and endurance. (Pre-)frailty is present in up to 42% of the older surgical population, with an increased risk for peri- and postoperative complications. Consequently, these patients often suffer from a delayed or limited recovery, loss of autonomy and quality of life, and a decrease in functional and cognitive capacities. Since frailty is modifiable, prehabilitation may improve the physiological reserves of patients and reduce the care dependency 12 months after surgery. Methods Patients ≥ 70 years old scheduled for elective surgery or intervention will be recruited in this multicenter, randomized controlled study, with a target of 1400 participants with an allocation ratio of 1:1. The intervention consists of (1) a shared decision-making process with the patient, relatives, and an interdisciplinary and interprofessional team and (2) a 3-week multimodal, individualized prehabilitation program including exercise therapy, nutritional intervention, mobility or balance training, and psychosocial interventions and medical assessment. The frequency of the supervised prehabilitation is 5 times/week for 3 weeks. The primary endpoint is defined as the level of care dependency 12 months after surgery or intervention. Discussion Prehabilitation has been proven to be effective for different populations, including colorectal, transplant, and cardiac surgery patients. In contrast, evidence for prehabilitation in older, frail patients has not been clearly established. To the best of our knowledge, this is currently the largest prehabilitation study on older people with frailty undergoing general elective surgery. Trial registration ClinicalTrials.gov NCT04418271 . Registered on 5 June 2020. Universal Trial Number (UTN): U1111-1253-4820