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Pediatric Inflammatory Multisystem Syndrome (PIMS-TS), associated with SARS-CoV-2 infection, is a severe complication after COVID-19 in children. It is caused by the immune reaction to SARS-CoV-2, and usually appears three to six weeks after the infection. Unfortunately, PIMS causes non-specific symptoms, which makes its diagnosis and treatment difficult. In this paper, we propose Fourier Transform InfraRed spectrometry (FTIR) to identify chemical changes in blood serum of children induced by PIMS and caused by subsequent treatment of the syndrome. The results suggest that although the Principal Component Analysis (PCA) of FTIR data did not allow for differentiation of healthy children and children with PIMS before and after the treatment, the implementation of Support Vector Machine (SVM) showed that the accuracy of the FTIR region between 800 cm - 1 and 1800 cm - 1 in PIMS detection is as high as 92% with a sensitivity of 100%. The difference in the chemical compositions of sera from the control group and the children after the treatment was detected in 54%, indicating that the treatment was effective. Indeed, the obtained medical data clearly showed a decrease of C-reactive protein (CRP) and Procalcitonin (PCT) concentration in serum after the treatment. The decision tree showed that peak 1455 cm - 1 could be used as a potential FTIR PIMS marker. Importantly, FTIR data correlates well with medical parameters, however the correlation differs with respect to the groups before and after the treatment., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Ethic declaration: This research was conducted according to the norm and standard in of the Declaration of Helsinki. This study was approved by the local Bioethics Committee of the Jagiellonian University (nr 1072.6120.360.2020). Moreover, written informed consent was obtained from the parents of the children from whom serum was collected. The consent was approved by the Bioethics Committee of the Jagiellonian University, (© 2025. The Author(s).)

The etiology of multisystem inflammatory syndrome in children (MIS-C), frequently observed following COVID-19 infection, remains elusive. This study unveils insights derived from cytokine analysis in the sera of MIS-C patients, both before and after the administration of intravenous immunoglobulin (IVIG) and glucocorticosteroids (GCS). In this study, we employed a comprehensive 45-cytokine profile encompassing a spectrum of widely recognized proinflammatory and antiinflammatory cytokines, as well as growth factors, along with other soluble mediators. The analysis delineates three principal cytokine-concentration patterns evident in the patients' sera. Pattern no.1 predominantly features proinflammatory cytokines (IL-6, IL-15, IL-1ra, granulocyte-macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor α (TNFα), C-X-C motif chemokine ligand 10 (CXCL10/ IP-10), and IL-10) exhibiting elevated concentrations upon admission, swiftly normalizing post-hospital treatment. Pattern no. 2 includes cytokines (IL-17 A, IL-33, IFNγ, vascular endothelial growth factor (VEGF), and programmed death ligand (PD-L1)) with moderately elevated levels at admission, persisting over 7-10 days of hospitalization despite the treatment. Pattern no. 3 comprises cytokines which concentrations escalated after 7-10 days of hospitalization and therapy, including IL-1α, IL-1β, IL-2, IL-13, platelet-derived growth factor AA/BB (PDGF AA/BB). The observed in cytokine profile of MIS-C patients showed a transition from acute inflammation to sustaining inflammation which turned into induction of humoral memory mechanisms and various defense mechanisms, contributing to recovery., (© 2024. The Author(s).)

The purpose of the study was to assess and compare short- and long-term cardiac complications of the multisystem inflammatory syndrome in children (MIS-C) by predominant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants throughout the pandemic. The analysis of prospectively collected data comparing cardiac complications of MIS-C during and after hospitalization across the original/alpha, delta, and omicron waves. Cardiac complications were defined as cardiac failure with systolic function impairment or hypotension or abnormalities in echocardiographic findings (decrease in LVEF, FS, valvular insufficiency, pericardial effusion, or coronary artery abnormalities). A total of 120 patients with MIS-C admitted to the Children's Hospital of Krakow between November 1, 2020, and May 5, 2023, were included in the study (74 during original/alpha dominance, 31 delta, and 15 omicron). Patients in the omicron group were found to be younger than those in the alpha and delta groups (37 vs. 75 vs. 80 months, p = 0.03). The frequency of cardiac failure with systolic function impairment or hypotension was diagnosed more frequently in the original/alpha and delta groups than in the omicron group (44.59% vs. 41.94% vs. 13.33%, p = 0.08) also echocardiographic abnormalities changed, with rates of 60.8%, 35.5%, and 13.3% (p < 0.001) accordingly. The multivariable regression revealed an older age (OR = 1.19, 95% CI = 1.07-1.33, p = 0.002) as the only independent factors of cardiac failure with systolic function impairment or hypotension. In all patients, signs of cardiac failure resolved during the hospitalization. Moreover, in 98.3% of patients, all echocardiagraphic abnormalities resolved completely during the observation period.    Conclusion: The cardiac complications of MIS-C appeared to advance less severely in younger children during the Omicron outbreak. In long-term observation, symptoms of cardiac failure resolve completely. Similarly, also echocardiographic abnormalities normalize in the vast majority of patients. What is Known: • Knowledge about the long-term cardiac complications of MIS-C is still evolving and uncertain. • The greatest concern of MIS-C is cardiac complications, including cardiac failure and coronary artery dilatation. What is New: • Long-term observations revealed complete resolution of cardiac complications in the vast majority of patients with MIS-C, irrespective of the dominant variant. • Cardiac complications of MIS-C were less common in younger children during subsequent pandemic waves in our patient population., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The purpose of this study is to assess the rate, clinical picture, and management of multisystem inflammatory syndrome in children (MIS-C) during the different COVID-19 variants of concern (VOC) domination periods. This was a retrospective analysis of prospectively collected data. The incidence and clinical picture of MIS-C during the original/Alpha (group 1) and Delta/Omicron (Group 2) variant domination periods were compared. Among 108 eligible patients, 74 (68.5%) were hospitalized during the group 1 domination period, and 34 (31.5%) were hospitalized during the group 2 domination period. The median (Me) patient ages were 76 months (interquartile range [IQR] 35-130) and 73 months (IQR 45-118), and 61% and 65% of patients were male, respectively. There was no significant difference in the presence of positive SARS-CoV 2 antibody test results (IgM or IgG) between the groups (84 vs. 90%; p = 0.54).No differences between groups were observed in fever duration prior to admission (Me [IQR]: 5 days [3-6] vs. 5 days [4-6]; p = 0.26) or the presence of mucocutaneous (95 vs. 100%; p = 0.41), circulatory (70.3 vs. 61.8%; p = 0.86), neurological (6.8 vs. 2.9%; p = 0.662), or gastrointestinal symptoms (84 vs. 79%; p = 0.59). Respiratory symptoms were more common in group 2 (70 vs. 91%; p = 0.015). The need for intensive care unit admission was similar in both groups (16.2 vs. 17.6%, p = 1.0). No deaths occurred in the entire cohort. The studied children were characterized by high C-reactive protein and procalcitonin levels, concentrations of ferritin within normal limits, lymphopenia, moderate hypoalbuminemia, and high B-type natriuretic peptide/brain natriuretic peptide (NT-proBNP) concentrations; however, there were no differences between the groups. Intravenous immunoglobulins were administered as a first-line treatment for almost all patients. There was no significant difference in corticosteroid administration between the groups (87% vs. 74%; p = 0.11); however, the summary dose of methylprednisolone was higher in group 2 (Me [IQR]″ 12.6 mg/kg [10.5-17.8] vs. 16.4 mg/kg [13.3-19.5]; p = 0.03). The median length of stay was 11 days [IQR]: [9-14] and 10 days [8-12], respectively (p = 0.065)., Conclusion: The clinical course of MIS-C is similar in subsequent pandemic waves; however, the incidence of MIS-C seems to be decreasing., What Is Known: • The clinical picture of COVID-19 is evolving. Multisystem inflammatory syndrome in children (MIS-C) is a relatively new serious disease connected with SARS-CoV-2 infection, and in subsequent waves of the pandemic, new cases of the disease have been recorded., What Is New: • The clinical picture of MIS-C is not specific, but the course is still severe. • The incidence of MIS-C during the different pandemic waves is decreasing and the diagnosis in the period of lower prevalance is challenging., (© 2023. The Author(s).)

Objective: A restrospective analysis of the clinical picture (inflammatory markers, characteristics of fever, comorbidities) in different clinical manifestations of human adenovirus (HAdV) infections confirmed using point-of-care testing in a group of hospitalized children. Material and Methods: A total of 135 children with confirmed HAdV infections were divided into three groups according to their clinical symptoms: Group A—respiratory (n = 57), Group B—gastrointestinal (n = 40), and Griup C—mixed (n = 38). Results: Respiratory and mixed HAdV-infected patients, as compared with gastrointestinal HAdV-infected patients, were younger (median value (Me) and interquartile range (IQR) (months): 17 (12−30) and 17 (12−27) vs. 30 (16−50), p = 0.04), had a longer duration of fever (days): 3 (1−5) and 3 (1−4) vs. 1 (1−2), p = 0.01), and had higher C-reactive protein values (mg/L): 29.2 (10.4−69.1) and 28.7 (10.8−49.1) vs. <5 (<5−20.6), p < 0.001). There were no correlations between CRP levels and patient’s age, fever duration, the occurrence of acute otitis media and lower respiratory tract infection, and antibiotic treatment before admission. Conclusions: Patients with respiratory HAdV infections have fevers more often, the duration of the fever prior to admission is longer, and CRP levels are higher.

Background: Enteroviral infections in infants <3 months of age are frequent and under-diagnosed even though they can be life-threatening. Properly conducted subjective examination, which is repeatedly neglected, plays a key role in the diagnosis and treatment of these infections., Materials and Methods: Analyses included children <3 months of age with confirmed enterovirus infection, hospitalised in the Department of Paediatrics from January 2019 to February 2020. Infections were confirmed by reverse transcription polymerase chain reaction in the cerebrospinal fluid using Neuro9 FTD set and in the stool using PB-03/Neuro; antibodies were determined in one patient., Results: This study presents a detailed description of three cases with confirmed enterovirus infection and a positive epidemiological history. The cases involve viral sepsis, myocarditis with arrhythmia and circulatory failure, and meningitis with seizures. In addition, the details of 10 patients hospitalised in the Children's Clinic with a confirmed enterovirus infection are presented. Based on these cases, a significant influence of family history-taking on the diagnosis and implementation of appropriate treatment was found., Conclusion: In most of the analysed cases, family history of viral infection was positive. In patients with the most severe course of the enterovirus infection, accurate epidemiological history is extremely important, and the suspicion of viral infection and securing appropriate materials for testing may significantly speed up the diagnosis in the newborn and help to implement an appropriate treatment., (© 2020 Anna Olchawa-Czech et al., published by Sciendo.)

Coughing is one of the most common patient complaints at physicians' office. The majority of children experience 5 to 8 episodes of cough lasting about a week throughout the year. Episodes of cough which last longer than 4 weeks, defined as a chronic cough, result in serious parental concern, impaired quality of life, increased number of medical consultations and the adverse effects of inappropriately used medications. Overall, a chronic cough is not only a serious health problem, but also a social one. The article presented below summarizes our current knowledge on the pathophysiology of chronic cough, the latest diagnostics and most recent measurement and monitoring methods as well as recommendations for therapeutic proceedings. In order to emphasize the distinct pathophysiology of chronic cough we use a new term: cough hypersensitivity syndrome. We point out the necessity of the concurrent implementation of more than one cough monitoring method for its more adequate evaluation. This article in addition presents the diagnostic and therapeutic algorithms in the treatment of a chronic cough which shorten the time to make a proper diagnosis, enable the introduction of adequate treatment, and ultimately improve the patients' quality of life. We present new therapeutic strategies, which are based on regulating the activity of vagal afferent nerves and modifying the neurotransmiters' transmission in the brainstem and midbrain.

We present an unexpected outcome of 10 years of enzyme replacement therapy of a boy with mucopolysaccharidosis type II. Due to a positive familiar history (severe disease course in a sibling) the diagnosis was established in the first month of life. Treatment with Elaprase was introduced two months later. Since then normal physical and mental development is observed. The patient presents only relatively large head circumference (+2.1 SD) and slight decrease of joints mobility. In our opinion, early introduction of enzyme replecement therapy could attenuate the disease course., (© Polish Society for Pediatric Endocrinology and Diabetology.)

Recent advances in molecular imaging and nanotechnology are providing new opportunities for biomedical imaging with great promise for the development of novel imaging agents. The unique optical, magnetic, and chemical properties of materials at the scale of nanometers allow the creation of imaging probes with better contrast enhancement, increased sensitivity, controlled biodistribution, better spatial and temporal information, multi-functionality and multi-modal imaging across MRI, PET, SPECT, and ultrasound. These features could ultimately translate to clinical advantages such as earlier detection, real time assessment of disease progression and personalized medicine. However, several years of investigation into the application of these materials to cancer research has revealed challenges that have delayed the successful application of these agents to the field of biomedical imaging. Understanding these challenges is critical to take full advantage of the benefits offered by nano-sized imaging agents. Therefore, this article presents the lessons learned and challenges encountered by a group of leading researchers in this field, and suggests ways forward to develop nanoparticle probes for cancer imaging. Published by Elsevier Ltd.

The new generation of nanotechnology-based drug formulations is challenging the accepted ways of cancer treatment. Multi-functional nanomaterial constructs have the capability to be delivered directly to the tumor site and eradicate cancer cells selectively, while sparing healthy cells. Tailoring of the nano-construct design can result in enhanced drug efficacy at lower doses as compared to free drug treatment, wider therapeutic window, and lower side effects. Nanoparticle carriers can also address several drug delivery problems which could not be effectively solved in the past and include reduction of multi-drug resistance effects, delivery of siRNA, and penetration of the blood-brain-barrier. Although challenges in understanding toxicity, biodistribution, and paving an effective regulatory path must be met, nanoscale devices carry a formidable promise to change ways cancer is diagnosed and treated. This article summarizes current developments in nanotechnology-based drug delivery and discusses path forward in this field. The discussion is done in context of research and development occurring within the NCI Alliance for Nanotechnology in Cancer program.

We examined the kinetic properties of voltage-gated Na(+) channels and their contribution to the repetitive spiking activity of medullary raphé neurons, which exhibit slow pacemaking and strong spiking adaptation. The study is based on a combination of whole-cell patch-clamp, modeling and real-time computation. Na(+) currents were recorded from neurons in brain slices obtained from male and female neonatal rats, using voltage-clamp protocols designed to reduce space-clamp artifacts and to emphasize functionally relevant kinetic features. A detailed kinetic model was formulated to explain the broad range of transient and stationary voltage-dependent properties exhibited by Na(+) currents. The model was tested by injecting via dynamic clamp a model-based current as a substitute for the native TTX-sensitive Na(+) currents, which were pharmacologically blocked. The model-based current reproduced well the native spike shape and spiking frequency. The dynamics of Na(+) channels during repetitive spiking were indirectly examined through this model. By comparing the spiking activities generated with different kinetic models in dynamic-clamp experiments, we determined that state-dependent slow inactivation contributes significantly to spiking adaptation. Through real-time manipulation of the model-based current, we established that suprathreshold Na(+) current mainly controls spike shape, whereas subthreshold Na(+) current modulates spiking frequency and contributes to the pacemaking mechanism. Since the model-based current was injected in the soma, the results also suggest that somatic Na(+) channels are sufficient to establish the essential spiking properties of raphé neurons in vitro.

Nanotechnology is a 'disruptive technology', which can lead to a generation of new diagnostic and therapeutic products, resulting in dramatically improved cancer outcomes. The National Cancer Institute (NCI) of National Institutes of Health explores innovative approaches to multidisciplinary research allowing for a convergence of molecular biology, oncology, physics, chemistry, and engineering and leading to the development of clinically worthy technological approaches. These initiatives include programmatic efforts to enable nanotechnology as a driver of advances in clinical oncology and cancer research, known collectively as the NCI Alliance for Nanotechnology in Cancer (ANC). Over the last 5 years, ANC has demonstrated that multidisciplinary approach catalyzes scientific developments and advances clinical translation in cancer nanotechnology. The research conducted by ANC members has improved diagnostic assays and imaging agents, leading to the development of point-of-care diagnostics, identification and validation of numerous biomarkers for novel diagnostic assays, and the development of multifunctional agents for imaging and therapy. Numerous nanotechnology-based technologies developed by ANC researchers are entering clinical trials. NCI has re-issued ANC program for next 5 years signaling that it continues to have high expectations for cancer nanotechnology's impact on clinical practice. The goals of the next phase will be to broaden access to cancer nanotechnology research through greater clinical translation and outreach to the patient and clinical communities and to support development of entirely new models of cancer care.

CD4+ T cells can differentiate into multiple effector subsets, but the potential roles of these subsets in anti-tumor immunity have not been fully explored. Seeking to study the impact of CD4+ T cell polarization on tumor rejection in a model mimicking human disease, we generated a new MHC class II-restricted, T-cell receptor (TCR) transgenic mouse model in which CD4+ T cells recognize a novel epitope in tyrosinase-related protein 1 (TRP-1), an antigen expressed by normal melanocytes and B16 murine melanoma. Cells could be robustly polarized into Th0, Th1, and Th17 subtypes in vitro, as evidenced by cytokine, chemokine, and adhesion molecule profiles and by surface markers, suggesting the potential for differential effector function in vivo. Contrary to the current view that Th1 cells are most important in tumor rejection, we found that Th17-polarized cells better mediated destruction of advanced B16 melanoma. Their therapeutic effect was critically dependent on interferon-gamma (IFN-gamma) production, whereas depletion of interleukin (IL)-17A and IL-23 had little impact. Taken together, these data indicate that the appropriate in vitro polarization of effector CD4+ T cells is decisive for successful tumor eradication. This principle should be considered in designing clinical trials involving adoptive transfer-based immunotherapy of human malignancies.

We propose what to our knowledge is a new technique for modeling the kinetics of voltage-gated ion channels in a functional context, in neurons or other excitable cells. The principle is to pharmacologically block the studied channel type, and to functionally replace it with dynamic clamp, on the basis of a computational model. Then, the parameters of the model are modified in real time (manually or automatically), with the objective of matching the dynamical behavior of the cell (e.g., action potential shape and spiking frequency), but also the transient and steady-state properties of the model (e.g., those derived from voltage-clamp recordings). Through this approach, one may find a model and parameter values that explain both the observed cellular dynamics and the biophysical properties of the channel. We extensively tested the method, focusing on Na(v) models. Complex Markov models (10-12 states or more) could be accurately integrated in real time at >50 kHz using the transition probability matrix, but not the explicit Euler method. The practicality of the technique was tested with experiments in raphe pacemaker neurons. Through automated real-time fitting, a Hodgkin-Huxley model could be found that reproduced well the action potential shape and the spiking frequency. Adding a virtual axonal compartment with a high density of Na(v) channels further improved the action potential shape. The computational procedure was implemented in the free QuB software, running under Microsoft Windows and featuring a friendly graphical user interface.

Action potential firing rates are generally limited by the refractory period, which depends on the recovery from inactivation of voltage-gated Na channels. In cerebellar Purkinje neurons, the kinetics of Na channels appear specialized for rapid firing. Upon depolarization, an endogenous open-channel blocker rapidly terminates current flow but prevents binding of the "fast" inactivation gate. Upon repolarization, unbinding of the blocker produces "resurgent" Na current while allowing channels to recover rapidly. Because other cerebellar neurons, including granule cells, unipolar brush cells, and neurons of the cerebellar nuclei, also fire rapidly, we tested whether these cells might also express Na channels with resurgent kinetics. Neurons were acutely isolated from mice and rats, and TTX-sensitive Na currents were recorded under voltage clamp. Unlike Purkinje cells, the other cerebellar neurons produced only tiny resurgent currents in solutions optimized for voltage-clamping Na currents (50 mM Na+; Co2+ substitution for Ca2+). Under more physiological ionic conditions (155 mM Na+; 2 mM Ca2+ with 0.03 mM Cd2+), however, granule cells, unipolar brush cells, and cerebellar nuclear cells all produced robust resurgent currents. The increase in resurgent current, which was greater than predicted by the Goldman-Hodgkin-Katz equation, appeared to result from a combination of knock-off of open-channel blockers by permeating ions as well as relief of divalent block at negative potentials. These results indicate that resurgent current is typical of many cerebellar neurons and suggest that rapid open-channel block and unblock may be a widespread mechanism for restoration of Na channel availability in rapidly firing neurons.

Computational models of single pacemaker neuron and neural population in the pre-Bötzinger Complex (pBC) were developed based on the previous models by Butera et al. (1999a,b). Our modeling study focused on the conditions that could define endogenous bursting vs. tonic activity in single pacemaker neurons and population bursting vs. asynchronous firing in populations of pacemaker neurons. We show that both bursting activity in single pacemaker neurons and population bursting activity may be released or suppressed depending on the expression of persistent sodium ( I(Na) P) and delayed-rectifier potassium ( I(K)) currents. Specifically, a transition from asynchronous firing to population bursting could be induced by a reduction of I(K) via a direct suppression of the potassium conductance or through an elevation of extracellular potassium concentration. Similar population bursting activity could be triggered by an augmentation of I(Na) P. These findings are discussed in the context of the possible role of population bursting activity in the pBC in the respiratory rhythm generation in vivo vs. in vitro and during normal breathing in vivo vs. gasping.

Rapidly inactivating and persistent sodium currents have been characterized in acutely dissociated neurons from the area of rostroventrolateral medulla that included the pre-Bötzinger Complex. As demonstrated in many studies in vitro, this area can generate endogenous rhythmic bursting activity. Experiments were performed on neonate and young rats (P1-15). Neurons were investigated using the whole cell voltage-clamp technique. Standard activation and inactivation protocols were used to characterize the steady-state and kinetic properties of the rapidly inactivating sodium current. Slow depolarizing ramp protocols were used to characterize the noninactivating sodium current. The "window" component of the rapidly inactivating sodium current was calculated using mathematical modeling. The persistent sodium current was revealed by subtraction of the window current from the total noninactivating sodium current. Our results provide evidence of the presence of persistent sodium currents in neurons of the rat rostroventrolateral medulla and determine voltage-gated characteristics of activation and inactivation of rapidly inactivating and persistent sodium channels in these neurons.

Substance P and neurokinin-1 receptors (NK1) modulate the respiratory activity and are expressed early during development. We tested the hypothesis that NK1 receptors are involved in prenatal development of the respiratory network by comparing the resting respiratory activity and the respiratory response to hypoxia of control mice and mutant mice lacking the NK1 receptor (NK1-/-). In vitro and in vivo experiments were conducted on neonatal, young and adult mice from wild-type and NK1-/- strains. In the wild strain, immunohistological, pharmacological and electrophysiological studies showed that NK1 receptors were expressed within medullary respiratory areas prior to birth and that their activation at birth modulated central respiratory activity and the membrane properties of phrenic motoneurons. Both the membrane properties of phrenic motoneurons and the respiratory activity generated in vitro by brainstem-spinal cord preparation from NK1-/- neonate mice were similar to that from the wild strain. In addition, in vivo ventilation recordings by plethysmography did not reveal interstrain differences in resting breathing parameters. The facilitation of ventilation by short-lasting hypoxia was similar in wild and NK1-/- neonates but was significantly weaker in adult NK1-/- mice. Results demonstrate that NK1 receptors do appear to be necessary for a normal respiratory response to short-lasting hypoxia in the adult. However, NK1 receptors are not obligatory for the prenatal development of the respiratory network, for the production of the rhythm, or for the regulation of breathing by short-lasting hypoxia in neonates.

The timing and activation pattern of breathing movements are determined by the respiratory network. This network is amenable to a variety of in vivo and in vitro approaches, which offers a unique opportunity to investigate multiple organizational levels. It is only recently, however, that concepts obtained under in vivo and in vitro conditions are being integrated into a coherent model of breathing behavior. For example, the pre-Bötzinger complex as an essential site for rhythm generation was first identified in vitro, but has since been verified in vivo. Conversely, timing signals provided by other central and peripheral neuronal areas have so far been investigated in vivo, but it is now possible to address these issues with more complex in vitro preparations. Several key issues remain unresolved. For example, to what extent is the respiratory pattern controlled independently of the underlying rhythm? Answers to this and other questions require a dissection of mechanisms that is only possible through a complementary combination of experimental approaches.

The hyperpolarization-activated cationic current (I(h)) was characterized and its maturation studied on phrenic motoneurons (PMNs), from reduced preparations of foetal (E18 and E21) and newborn (P0-P3) rats, using the whole-cell patch-clamp technique. In voltage-clamp mode, 2-s hyperpolarizing steps (5-mV, -50 to -110 mV) elicited a noninactivating inward current, blocked by external application of Cs+ or ZD 7288. At -110 mV, Ih current density averaged 0.67 +/- 0.41 pA/pF at E18, reached a transient peak at E21 (1.38 +/- 0.11 pA/pF) and decreased at P0-P3 (0.77 +/- 0.22 pA/pF). V1/2 was similar at E18 and E21 (-79 mV) but was significantly hyperpolarized at P0-P3 (-90 mV). The time constant of activation was voltage-dependent, and significantly faster at E21. Reversal potential was similar at all ages when estimated by extrapolation or tail current procedures. It was positively shifted by 25 +/- 6 mV when external potassium was raised from 3 to 10 m M, suggesting a similar sensitivity to K+ from E18 to P0-3. Cs(+) or ZD 7288 applications on PMNs at rest in current-clamp mode, in a partitioned chamber, induced a 10 +/- 2 mV hyperpolarization at E18 and E21, and an 8 +/- 2 mV hyperpolarization at P0-3. The area of the central respiratory drive potential or current was increased by 33 and 31%, respectively, at E21, but was not significantly modified at E18 and P0-3. Our data suggest a critical period during the perinatal maturation of Ih during which it is transiently upregulated and attenuates the influence of the central respiratory drive on PMNs just prior to birth.

Considerable evidence from several laboratories (c.f., Rekling and Feldman, Ramirez et al.) is consistent with the concept that the pBc contains the kernel of the central rhythm generating network for breathing. The work summarized in this manuscript is also generally consistent with this notion. Of particular note is the observation that pre-I neurons and E-Dec neurons maintain a consistent phase relationship with phrenic nerve activity and maintain a similar peak discharge rate despite marked changes in the phrenic nerve rhythm and pattern. Other categories of respiratory neurons failed to maintain this relationship. Hence, the findings are consistent with pBc pre-I and E-Dec neurons having a key role in rhythm generation. A persistent sodium current has been postulated to underlie the rhythm generating mechanism of pacemaker neurons within the pBc. In the present study, a substantial persistent sodium current was documented in many neurons from the pBc and adjacent respiratory regions. This finding is not inconsistent with the postulated role in rhythm generation. However, it does suggest that other neuronal properties must act in concert with the persistent current to define a unique population of pacemaker neurons.

Neurokinin-1 receptors (NK1) are present within the respiratory medullary network and in the phrenic nucleus, which controls the diaphragm. We compared the efficacy of substance P (SP) at inducing changes in respiratory frequency or the amplitude of the respiratory motor output between NK1 knockout (NK1-/-) and wild-type mice, using the in vitro brainstem-spinal cord preparation. The in vitro respiratory frequency, as well as the variability of the rhythm and the amplitude of the motor output were similar in both lines. In wild-type mice, application of exogenous SP induced either an increase in respiratory frequency (superfusion of the medulla) or an increase of the inspiratory motor output, as defined by the integral of C4 cervical ventral root activity (superfusion of the spinal cord). These two effects were not apparent in NK1-/- mice. In conclusion, NK1 receptors mediate the respiratory responses to SP but the lack of NK1 receptors in newborn NK1-/- mice does not change the respiratory activity.

Experiments were carried out on the in vitro brainstem-spinal cord preparation of the newborn rat to analyse the effects of substance P (SP) on phrenic motoneuron (PMN) activity. In current-clamp mode, SP significantly depolarized PMNs, increased their input resistance, decreased the rheobase current and shifted the firing frequency-intensity relationships leftwards, but did not affect spike frequency adaptation or single spike configuration. The neurokinin receptor agonist NK1 had SP-mimetic effects, whereas the NK3 and NK2 receptor agonists were less effective and ineffective, respectively. In a tetrodotoxin-containing aCSF, only SP or the NK1 receptor agonist were still active. No depolarization was observed when the NK1 receptor agonist was applied in the presence of muscarine. In voltage-clamp mode, SP or the NK1 receptor agonist produced an inward current (ISP) which was not significantly reduced by extracellular application of tetraethylammonium, Co2+, 4-aminopyridine or Cs+. In aCSF containing tetrodotoxin, Co2+ and Cs+, ISP was blocked by muscarine. No PMN displayed any M-type potassium current but only a current showing no voltage sensitivity over the range -100 to 0 mV, reversing near the expected EK +, hence consistent with a leak current. SP application to the spinal cord only (using a partitioned chamber) significantly increased the phrenic activity. Pretreatment with the NMDA receptor antagonist DL-2-amino-5-phosphonovaleric acid (AP5) decreased the C4 discharge duration and blocked the effect of SP, thus exhibiting an NMDA potentiation by SP. In conclusion, SP modulates postsynaptically the response of phrenic motoneurons to the inspiratory drive through the reduction of a leak conductance and the potentiation of the NMDA component of the synaptic input.

Experiments were performed in vitro on foetal (embryonic days 18 to 21, E18-21) and newborn rat (postnatal days 0 to 3, P0-3) brainstem spinal cord preparations to analyse the perinatal developmental changes in the effects induced by substance P. Superfusion of the preparations with SP-containing artificial cerebrospinal fluid (aCSF) induced significant increase in the respiratory frequency of newborn rats (10-9 M), whereas concentration up to 10-7 M induced no change in foetal preparations. A whole cell patch clamp approach was used to record intracellularly from phrenic motoneurones. In newborn or E20-21 foetal rats SP-containing aCSF depolarised the phrenic motoneurones, increased their input resistance, reduced the rheobase current and shifted the frequency-intensity curves upward. In E18 foetal rats, no change was evoked by SP. A peptidase inhibitor mixture was used to block the enzymatic degradation of endogenous SP. This mixture was ineffective in changing the respiratory frequency in newborn and foetal preparations. In newborn rat phrenic motoneurones, the peptidase inhibitor mixture induced changes similar to those caused by SP but no change was induced in foetal rats. These results indicate that SP may modulate (i) the activity of the respiratory rhythm generator in newborn but not in foetal rats, and (ii) the activity of phrenic motoneurones at E20, E21 and in newborn rats but not at E18. Results obtained using the peptidase inhibitor mixture suggest that endogenous SP is probably not involved in the control of the respiratory rhythm in the prenatal period, but may influence the activity of the phrenic motoneurones after birth., (Copyright 1999 Elsevier Science B.V.)

For many years, industry has utilized the concept of human error rates to monitor and minimize human errors in the production process. A consistent quality-controlled product increases consumer satisfaction and repeat purchase of product. Administrative dietitians have applied the concepts of using human error rates (the number of errors divided by the number of opportunities for error) at four hospitals, with a total bed capacity of 788, within a tertiary-care medical center. Human error rate was used to monitor and evaluate trayline employee performance and to evaluate layout and tasks of trayline stations, in addition to evaluating employees in patient service areas. Long-term employees initially opposed the error rate system with some hostility and resentment, while newer employees accepted the system. All employees now believe that the constant feedback given by supervisors enhances their self-esteem and productivity. Employee error rates are monitored daily and are used to counsel employees when necessary; they are also utilized during annual performance evaluation. Average daily error rates for a facility staffed by new employees decreased from 7% to an acceptable 3%. In a facility staffed by long-term employees, the error rate increased, reflecting improper error documentation. Patient satisfaction surveys reveal satisfaction, for tray accuracy increased from 88% to 92% in the facility staffed by long-term employees and has remained above the 90% standard in the facility staffed by new employees.