Spontaneous Opening Research Articles

The Human Stuff: Recognising Devalued Expertise in a Steel Mill

In a challenging and involuntary role-change process in a traditional industrial environment, a spontaneous opening appeared so that room for man-to-man appreciation could be made, leading to a greater level of humanity, concern and community. This contributed to a feeling of safety among the work group, which in turn supported and expedited acceptance of the change.

Spontaneous calcium transients in hair cell stereocilia.

The hair bundle of auditory and vestibular hair cells converts mechanical stimuli into electrical signals through mechanoelectrical transduction (MET). The MET apparatus is built around a tip link that connects neighboring stereocilia that are aligned in the direction of mechanosensitivity of the hair bundle. Upon stimulation, the MET channel complex responds to changes in tip-link tension and allows a cation influx into the cell. Ca 2+ influx in stereocilia has been used as a signature of MET activity. Using genetically encoded Ca 2+ sensors (GCaMP3, GCaMP6s) and high-performance fluorescence confocal microscopy, we detect spontaneous Ca 2+ transients in individual stereocilia in developing and fully formed hair bundles. We demonstrate that this activity is abolished by MET channel blockers and thus likely originates from putative MET channels. We observe Ca 2+ transients in the stereocilia of mice in tissue explants as well as in vivo in zebrafish hair cells, indicating this activity is functionally conserved. Within stereocilia, the origin of Ca 2+ transients is not limited to the canonical MET site at the stereocilia tip but is also present along the stereocilia length. Remarkably, we also observe these Ca 2+ transients in the microvilli-like structures on the hair cell surface in the early stages of bundle development, prior to the onset of MET. Ca 2+ transients are also present in the tallest rows of stereocilia in auditory hair cells, structures not traditionally thought to contain MET channels. We hypothesize that this newly described activity may reflect stochastic and spontaneous MET channel opening. Localization of these transients to other regions of the stereocilia indicates the presence of a pool of channels or channel precursors. Our work provides insights into MET channel assembly, maturation, function, and turnover.

Unintentional poisoning exposures: how does modeling the opening of child-resistant containers influence children's behaviors?

Unintentional poisoning in the home is a risk for children. Over-the-counter medicinal products in child-resistant containers (CRC) are common causes of pediatric poisoning. The current study examined children's abilities to open three types of CRC mechanisms (twist, flip, and push) and corresponding control containers, comparing their ability to do so spontaneously and after explicit modeling. The study also examined if inhibitory control (IC) was associated with children's overall score for spontaneous openings. Children 5-8 years old were randomly assigned to one of three mechanism conditions (between-participants factor): twist, flip, and push, with each child experiencing both a risk and a control container (within-participants factor) having that mechanism. Children were first left alone with a container (measures: engagement with container, spontaneous opening) for up to 2 min and subsequently observed an adult explicitly model opening the container before the child was asked to do so (measure: opening after modeling). Children were more engaged with and likely to spontaneously open control containers than CRCs, though some (4%-10%) also opened CRCs. After modeling, significantly more children opened each of the three types of CRCs, with nearly all children opening the push mechanism CRC. IC positively predicted children being more engaged with and spontaneously opening more containers. Implications for improving pediatric poison prevention are discussed.

Effect of bispectral index on intra-operative awareness: A meta-analysis of randomized controlled studies.

Randomized controlled trials (RCTs) investigating the efficacy of bispectral index (BIS) to reduce intra-operative awareness (IOA) have reported conflicting results. The purpose of this meta-analysis is to consolidate results from RCTs to assess the efficacy of BIS in reducing IOA when compared to controls. Secondary outcomes included time to extubation, time to spontaneous and/or verbal eye opening, PACU discharge time, and utilization of inhaled anesthetics. RCTs which reported on one of the primary and/or secondary outcomes were included. Literature search utilized keywords "randomized control trial" and "intraoperative awareness." Meta-analysis was performed using RevMan 5. Twenty-seven RCTs were included in the study with a total of 35,585 patients, with 18,146 patients in the BIS and 17,439 in the control group. Eighteen of 14,062 patients (0.12%) and 42 of 16,765 (0.25%) reported definite IOA in the BIS and control group, respectively, with no statistically significant difference. BIS was effective in reducing the time to spontaneous eye opening by an average of 1.3 minutes and the time to extubation by an average of 1.97 minutes. There was no difference in PACU discharge times among the groups. There was a significant decrease in consumption of sevoflurane but no difference in desflurane and propofol compared to the control group. While BIS monitoring results in decreased incidence of intra-operative awareness by half, it was not statistically significant. BIS provides modest benefits with regard to reducing the time to extubation, the time to spontaneous eye opening, and consumption of sevoflurane.Level of evidence: I.

High prevalence of orofacial pain in juvenile fibromyalgia as detected by a novel tool specifically devised for children and adolescents.

To examine the prevalence of temporomandibular disorders (TMD) in patients with juvenile fibromyalgia syndrome (JFS) and identify TMD characteristics specifically associated to JFS. Signs and symptoms of TMD were assessed using a novel clinical tool specifically devised for children that consists of: 1. a self-report multiple-choice questionnaire; 2. a protocol for the clinical examination of the orofacial region. Multivariate logistic regression model was used to identify TMD features associated with JFS. Thirty JFS patients (median age 15.5 years) and 45 healthy controls (median age 15.0 years) were included in this cross-sectional study. Orofacial pain was reported by 26 of 30 JFS patients (86.7%) and by 3 of 45 controls (6.7%; p<0.001). Pain on TMJ palpation was present in 18 of 30 JFS patients (60%) and in 5 of 45 controls (11.1%; p<0.001). Median values of maximum spontaneous mouth opening, voluntary active opening and assisted passive opening were significantly higher in JFS patients than in controls. On multiple regression analysis spontaneous orofacial pain (OR: 21.0; p=0.005), diffuse tenderness on palpation of the masticatory muscles (OR: 14.9; p=0.026) and TMJ hypermobility (OR 1.42; p=0.008) were independently associated with JFS. The high prevalence of TMD in JFS highlights the need for a broader interdisciplinary evaluation of JFS patients. TMJ hypermobility, in addition to orofacial and masticatory muscle pain, is an important clue for the diagnosis of TMD in adolescents with JFS. Elucidating the link between these disorders will advance individualised management and improve treatment efficacy.

Neurosteroid Modulation of Synaptic and Extrasynaptic GABAA Receptors of the Mouse Nucleus Accumbens.

The recent approval of formulations of the endogenous neurosteroid allopregnanolone (brexanolone) and the synthetic neuroactive steroid SAGE-217 (zuranolone) to treat postpartum depression (PPD) has encouraged further research to elucidate why these potent enhancers of GABAAR function are clinically effective in this condition. Dopaminergic projections from the ventral tegmental area (VTA) to the nucleus accumbens are associated with reward/motivation and brain imaging studies report that individuals with PPD show reduced activity of this pathway in response to reward and infant engagement. However, the influence of neurosteroids on GABA-ergic transmission in the nucleus accumbens has received limited attention. Here, we investigate, in the medium spiny neurons (MSNs) of the mouse nucleus accumbens core, the effect of allopregnanolone, SAGE-217 and other endogenous and synthetic steroids of interest on fast phasic and tonic inhibition mediated by synaptic (α1/2βγ2) and extrasynaptic (α4βδ) GABAARs, respectively. We present evidence suggesting the resident tonic current results from the spontaneous opening of δ-GABAARs, where the steroid-enhanced tonic current is GABA-dependent. Furthermore, we demonstrate local neurosteroid synthesis in the accumbal slice preparation and reveal that GABA-ergic neurotransmission of MSNs is influenced by an endogenous neurosteroid tone. Given the dramatic fluctuations in allopregnanolone levels during pregnancy and postpartum, this neurosteroid-mediated local fine-tuning of GABAergic transmission in the MSNs will probably be perturbed.

Трансформація поглядів на ведення жінок з істміко-цервікальною недостатністю

Cervical cerclage is an obstetric procedure used to prevent late term spontaneous abortions and preterm birth in women at high risk of miscarriage. Taking into consideration existance of insufficient effectiveness of methods for preventing spontaneous preterm labor, as evidenced by the lack of significant changes in statistical data over the past 10 years, further research is needed to improve the tactics of managing pregnant women, especially from the group of high risk of this complication. Cervical cerclage allows to mechanically stop the process of spontaneous opening of the cervix, however, although the method is minimally invasive, when using it, there is still a risk of complications, such as infection or trauma to the cervix. Taking this into account, determining the groups of patients who will benefit the most from this intervention is essential. Today, this issue is undergoing a number of transformations and updates which we tried to analyze in this work. Aim - determining changes in the recommendations for surgical management of women with isthmico-cervical insufficiency based on the analysis of the latest recommendations of the National Institute for Health and Care Excellence and the Royal College of Obstetricians and Gynecologists. Results and conclusions. According to the 2022 guidelines, along with slightly changed approaches to the classification and terminology of cervical cerclage, there has been some transformation in views about the groups of women who will benefit the most from the procedure. First of all, according to anamnestic data, cervical suture is recommended for three anamnestic episodes of miscarriage instead of two in the previous recommendations. On ultrasound examination, a wedge-shaped transformation of the cervix and incidental detection of cervical shortening after 20 weeks is not an indication for applying a cerclage, since the effectiveness of the intervention in this case is unproven. In addition, new techniques, such as abdominal cerclage, have been invented to more effectively prevent episodes of miscarriage. No conflict of interests was declared by the authors.

Spontaneous Gap Opening and Potential Excitonic States in an Ideal Dirac Semimetal Ta2Pd3Te5

The opening of an energy gap in the electronic structure generally indicates the presence of interactions. In materials with low carrier density and short screening length, long-range Coulomb interaction favors the spontaneous formation of electron-hole pairs, so called excitons, opening an excitonic gap at the Fermi level. Excitonic materials host unique phenomena associated with pair excitations. However, there is still no generally recognized single-crystal material with excitonic order, which is, therefore, awaited in condensed matter physics. Here, we show that excitonic states may exist in the quasi-one-dimensional material Ta2Pd3Te5, which has an almost ideal Dirac-like band structure, with the Dirac point located exactly at the Fermi level. We find that an energy gap appears at 350 K, and it grows with decreasing temperature. The spontaneous gap opening is absent in a similar material Ta2Ni3Te5. Intriguingly, the gap is destroyed by the potassium deposition on the crystal, likely due to extra-doped carriers. Furthermore, we observe a pair of in-gap flat bands, which is an analog of the impurity states in a superconducting gap. All these observations can be properly explained by an excitonic order, providing Ta2Pd3Te5 as a new and promising candidate realizing excitonic states. Published by the American Physical Society 2024

Comparison of Haemodynamic Stability and Early Recovery Characteristics of Desflurane versus Sevoflurane in Robotic Prostatectomy: A Randomised Clinical Study

Introduction: An ideal anaesthetic for robotic surgery would allow for a quick induction with minimal discomfort, as well as a short operation duration, quick recovery, and minimal aftereffects. Additionally, it would enable speedy recovery. Aim: To compare the haemodynamic stability and recovery characteristics of sevoflurane with desflurane for robotic surgery. Materials and Methods: The present randomised clinical study was conducted for four years from January 2019 to January 2023 and included 60 patients undergoing elective robotic radical prostatectomy and randomised into the group receiving desflurane (Group D) and that receiving sevoflurane (Group S). All patients were monitored using the Bispectral index (BIS) monitor, in addition to standard monitoring. General anaesthesia was administered using midazolam, fentanyl, propofol, atracurium, and either desflurane or sevoflurane based on the assigned group. Throughout the surgery, patients’ haemodynamic stability was monitored, and vital signs were recorded at induction, intubation, after assuming the Trendelenburg position, and at 30-minute intervals, until extubation. The inhalational agent was turned off at skin closure, and the time to spontaneous eye opening (T1), time to extubation (T2), and time to verbal response (T3) were noted. After the verbal response, patients were assessed based on the Modified Aldrete Score (MAS) with a threshold of ≥9. Pulse rate, blood pressure, BIS, and MAS were recorded during this time period. Data was presented as mean, frequency, and percentage. MAS comparison among the study groups was assessed using the Chi-square test. Demographic, haemodynamic, and BIS variables were compared using paired t-tests. Results: The mean age of patients in group S was 67.67±6.07 years, while in group D, it was 65.17±6.69 years. The time required for extubation after turning off the agent was significantly shorter in group-D compared to group-S, with a mean of 16.07±13.00 minutes in group-D and 21.71±9.07 minutes in group-S (p-value=0.0001). The percentage of patients achieving MAS &gt;9 at five minutes was significantly higher in group D. Additionally, the use of both agents was not associated with any major complications. Conclusion: Desflurane as the inhalational agent ensures faster recovery in the early postoperative period and minimal changes in haemodynamic parameters compared to sevoflurane. However, sevoflurane has fewer complications compared to desflurane.

Terapia com cães para crianças com síndrome do zika: percepção de mães e profissionais

ABSTRACT Objective: To assess the perceptions of mothers and health professionals about the dog-assisted therapy for children with congenital Zika Virus syndrome. Method: Qualitative, descriptive-exploratory research, with six mothers of children with congenital Zika Virus syndrome and six health professionals. Data were obtained at a Brazilian Specialized rehabilitation center in Paraíba, through semi-structured interviews, between February and October 2019. The empirical material was subjected to Inductive Thematic Analysis and interpreted using the Bronfenbrenner’s Bioecological Theory. Results: Dog-Assisted Therapy allowed the enhancement of skills that were previously not performed by children, such as: spontaneous hand opening, head control, improved social interaction, reduction of seizure episodes and disruption of spasticity patterns. Final considerations: Dog-Assisted Therapy was perceived as qualified, humanized and satisfactory support for the evolution of the neuropsychomotor development of children with congenital Zika Virus syndrome.

Hippocampal volume and recovery profile following propofol sedation in children undergoing magnetic resonance imaging: An exploratory study.

Reduction in the hippocampal volume may contribute to agitated and delayed emergence after anesthesia in epilepsy surgery. We hypothesized that hippocampal volume and the duration of various recovery parameters after a short duration of sedation may be correlated. The primary objective was to evaluate the correlation between hippocampal volumes with time to recovery after the stoppage of propofol infusion. After obtaining Institute Ethical Clearance, we included all children of the age group 5-17 years, who needed sedation for brain magnetic resonance imaging (MRI) for at least 20-60 minutes for the evaluation of epilepsy. The hippocampal volume was estimated bilaterally in the pre-contrast volumetric magnetization-prepared rapid gradient-echo (MPRAGE) brain imaging by the radiologist using statistical parametric mapping. The correlation of hippocampal volume with recovery and time to discharge (assessed by the modified Aldrete score (MAS)) was obtained using Spearman's correlation coefficient (rho). A rho > ± 0.5 was considered a good correlation between the variables. Data on a total of 18 children (10 males and 8 females) who required sedation for an MRI were studied over a period of six months. The correlation coefficients of right and left corrected hippocampal volumes with time to spontaneous eye opening were -0.052 and -0.195, respectively. The correlation coefficients of right and left corrected hippocampal volumes with time to respond to oral commands were -0.017 and -0.219, respectively. There was a weak negative correlation between hippocampal volumes and recovery parameters after a short duration of sedation with propofol in children.

Influence of the postoperative restrictive methodologies and efficacy of the Baerveldt 350 implant after 12 months follow‐up

Aims/Purpose: To assess the clinical outcomes subsequent to the implantation of a Baerveldt 350 drainage device, utilizing different restrictive methodologies to prevent sudden postoperative hypotony (HT) (IOP &lt;6 mmHg), and their subsequent impact on the incidence of a Hypertensive phase (HP).Methods: A retrospective observational analysis of 71 consecutive eyes that had a Baerveldt 350 implanted. 50 eyes had 6 or 7/0 polyglactin tube ligation (ligature group = LG) and 21 eyes had a 3/0 polypropylene intraluminal tear cord 3/0 added to the ligation (ripcord‐ligature group = RLG), which was manually removed at the surgeon's discretion after spontaneous opening of the polyglactin. Intraocular pressure (IOP) and ocular hypotensive medication (OHM) lowering, failure rate, complete and partial success (CS and PS) and presence of HP were analysed.Results: The mean preoperative IOP was 26.14 (11.34) mmHg with 2.98 OHM for the LG and 28 (8.76) mmHg with 3.35 OHM for the RLG (p = 0.545 and p = 0.397). At the end of the follow‐up, the mean postoperative IOP was 13.35 (3.87) mmHg for the LG and 10.81(2.66) mmHg for the RLG (p = 0.01). The mean reduction of OHM was 2.25 (1.38) for the LG and 2.81 (1.6) for the RLG (p = 0.168). HP was noted in 26 patients (37.14%), 25 of them took place in the LG (50%); however, only 1 took place in the RLG (5%) (p = 0.00023). 35% of the patients who exhibited HP achieved CS, compared to 67.7% of the patients that did not show HP (p = 0.022). The survival analysis for a 12 months follow‐up period, showed that the estimate survival time for the LG was 10.97 (±0.521), and 11.64 (±0.342) for the RLG (p = 0.216). Two predictors were identified for risk of failure and CS: age of the patient before surgery (OR 0.157; 95% CI 0.029–0.865; p = 0.033) and the presence of HP (OR 3.90; 95% CI 1.189–12.794; p = 0.025). Lastly, HT was noted in 55 patients (80.9%), 45 of them took place in the LG (81.8%); however, only 10 took place in the RLG (18.2%) (Pearson Chi‐S p = 0.000225).Conclusions: Baerveldt 350 drainage device implantation has proven to be an effective procedure for glaucoma control. The use of the ripcord added to the absorbable ligature was associated with less risk of HP, and with better IOP results at the 12‐months follow‐up. Nevertheless, further research with larger population and larger follow‐up is needed to obtain robust results.

Readiness of nociceptor cell bodies to generate spontaneous activity results from background activity of diverse ion channels and high input resistance.

Nociceptor cell bodies generate "spontaneous" discharge that can promote ongoing pain in persistent pain conditions. Little is known about the underlying mechanisms. Recordings from nociceptor cell bodies (somata) dissociated from rodent and human dorsal root ganglia have shown that previous pain in vivo is associated with low-frequency discharge controlled by irregular depolarizing spontaneous fluctuations of membrane potential (DSFs), likely produced by transient inward currents across the somal input resistance. Using mouse nociceptors, we show that DSFs are associated with high somal input resistance over a wide range of membrane potentials, including depolarized levels where DSFs approach action potential (AP) threshold. Input resistance and both the amplitude and frequency of DSFs were increased in neurons exhibiting spontaneous activity. Ion substitution experiments indicated that the depolarizing phase of DSFs is generated by spontaneous opening of channels permeable to Na + or Ca 2+ and that Ca 2+ -permeable channels are especially important for larger DSFs. Partial reduction of the amplitude or frequency of DSFs by perfusion of pharmacological inhibitors indicated small but significant contributions from Nav1.7, Nav1.8, TRPV1, TRPA1, TRPM4, and N-type Ca 2+ channels. Less specific blockers suggested a contribution from NALCN channels, and global knockout suggested a role for Nav1.9. The combination of high somal input resistance plus background activity of diverse ion channels permeable to Na + or Ca 2+ produces DSFs that are poised to reach AP threshold if resting membrane potential depolarizes, AP threshold decreases, or DSFs become enhanced-all of which can occur under painful neuropathic and inflammatory conditions.

Three tests to determine a preferred chewing side in partially edentulous patients: A pilot study

Determining the preferred chewing side may be an important factor in prosthetic treatment planning, especially where additional support for a removable dental prosthesis can be provided by implants. The purpose of this clinical study was to investigate the validity and reproducibility of 3 different tests to determine the preferred chewing side. A total of 82 partial denture wearers, with an average age of 70 years, were enrolled in this study. The first test (CG) evaluated the left or right position of a piece of chewing gum after spontaneous mouth opening during mastication. A second test (ASI) videotaped 30 seconds of mastication and analyzed the distribution of masticatory cycles by means of an asymmetry index. For the third test (VAS), participants were asked to mark their subjective perception of their preferred chewing side on a visual analog scale representing the right and left sides. All the tests were performed and repeated in a randomized sequence. The reproducibility of the tests was first evaluated. The mean values of the ASI and VAS tests were calculated, and the results were compared with the second series of the CG test. The Pearson correlation test was used to associate ASI and VAS, and the Cohen kappa agreement was used for the inter-reliability of CG (α=.01). The results indicated fair to almost perfect reproducibility for the 3 tests. Kappa values were.37 (P<.01) for the CG,.47 (P<.01) for the ASI and.91 (P<.01) for the VAS. Correlation coefficients resulted in rho=.86 (P<.01) for the ASI and rho=.97 (P<.01) for the VAS. The correlation between ASI and VAS was excellent, with rho=.85 (P<.010). CG and ASI (test kappa=.36, P<.010) and CG and VAS (test kappa=.39, P<.010) showed fair agreement. ASI and VAS seem more reliable than CG to determine a patient's preferred chewing side and might be helpful within the context of prosthetic treatment planning, where additional support may improve denture function.

Binding and Sliding Dynamics of the Hepatitis C Virus Polymerase: Hunting the 3' Terminus.

The hepatitis C virus (HCV) nonstructural protein 5B (NS5B) polymerase catalyzes the replication of the (+) single-stranded RNA genome of HCV. In vitro studies have shown that replication can be performed in the absence of a primer. However, the dynamics and mechanism by which NS5B locates the 3'-terminus of the RNA template to initiate de novo synthesis remain elusive. Here, we performed single-molecule fluorescence studies based on protein-induced fluorescence enhancement reporting on NS5B dynamics on a short model RNA substrate. Our results suggest that NS5B exists in a fully open conformation in solution wherefrom it accesses its binding site along RNA and then closes. Our results revealed two NS5B binding modes: an unstable one resulting in rapid dissociation, and a stable one characterized by a larger residence time on the substrate. We associate these bindings to an unproductive and productive orientation, respectively. Addition of extra mono (Na+)- and divalent (Mg2+) ions increases the mobility of NS5B along its RNA substrate. However, only Mg2+ ions induce a decrease in NS5B residence time. Dwell times of residence increase with the length of the single-stranded template, suggesting that NS5B unbinds its substrate by unthreading the template rather than by spontaneous opening.

Building a tissue: Mesenchymal and epithelial cell spheroids mechanical properties at micro- and nanoscale.

Cell transitions between the epithelial and mesenchymal phenotypes provide the regulated morphogenesis and regeneration throughout the ontogenesis. The tissue mechanics and mechanotransduction play an essential role in these processes. Cell spheroids reproduce the cell density of native tissues and represent simple building blocks for the tissue engineering purposes. The mechanical properties of mesenchymal and epithelial cells have been extensively studied in 2D monolayer cultures, but have not been sufficiently compared in spheroids. Here, we have simultaneously applied several techniques to assess the mechanical parameters of such spheroids. The local surface mechanical properties were measured by AFM, and the bulk properties were analyzed with parallel-plate compression, as well as by observing cut opening after microdissection. The comparison of the collected data allowed us to apply the model of a solid body with surface tension, and estimate the parameters of this model. We found an expectedly higher surface tension in mesenchymal spheroids, as well as a higher bulk modulus and relaxation time. The two latter parameters agree with the bulk poroelastic behavior of spheroids, and with the higher cell density and extracellular matrix content in mesenchymal spheroids. The higher tension of the surface layer cells in mesenchymal cell spheroids was also confirmed by the viscoelastic AFM characterization. The cell phenotype affected the self-organization during the spheroid formation, as well as the structure, biomechanical properties, and spreading of spheroids. The obtained results will contribute to a more detailed description of spheroid and tissue biomechanics, and will help in controlling the tissue regeneration and morphogenesis. STATEMENT OF SIGNIFICANCE: Spheroids are widely used as building blocks for scaffold-based and scaffold-free strategies in tissue engineering. In most studies, either the concept of a solid body or a liquid with surface tension was used to describe the biomechanical behavior of spheroids. Here, we have used a model which combines both aspects, a solid body with surface tension. The "solid" aspect was described as a visco-poroelastic material, affected by the liquid redistribution through the cells and ECM at the scale of the whole spheroid. A higher surface tension was found for mesenchymal spheroids than that for epithelial spheroids, observed as a higher stiffness of the spheroid surface, as well as a larger spontaneous opening of the cut edges after microdissection.

A novel force transduction pathway from a tension sensor to the gate in the mechano-gating of MscL channel.

The bacterial mechanosensitive channel of large conductance MscL is activated exclusively by increased tension in the membrane bilayer. Despite many proposed models for MscL opening, its precise mechano-gating mechanism, particularly how the received force at the tension sensor transmits to the gate remains incomplete. Previous studies have shown that along with amphipathic N-terminus located near the cytoplasmic surface of the membrane, Phe78 residue near the outer surface also acts as a "tension sensor," while Gly22 is a central constituent of the "hydrophobic gate." Present study focused on elucidating the force transmission mechanism from the sensor Phe78 in the outer transmembrane helix (TM2) to the gate in the inner transmembrane helix (TM1) of MscL by applying the patch clamp and molecular dynamics (MD) simulations to the wild type MscL channel and its single mutants at the sensor (F78N), the gate (G22N) and their combination (G22N/F78N) double mutant. F78N MscL resulted in a severe loss-of-function, while G22N MscL caused a gain-of-function channel exhibiting spontaneous openings at the resting membrane tension. We initially speculated that the spontaneous opening in G22N mutant might occur without tension acting on Phe78 residue. To test this hypothesis, we examined the (G22N/F78N) double mutant, which unexpectedly exhibited neither spontaneous activity nor activity by a relatively high membrane tension. To understand the underlying mechanism, we conducted MD simulations and analyzed the force transduction pathway. Results showed that the mutation at the tension sensor (F78N) in TM2 caused decreased interaction of this residue not only with lipids, but also with a group of amino acids (Ile32-Leu36-Ile40) in the neighboring TM1 helix, which resulted in an inefficient force transmission to the gate-constituting amino acids on TM1. This change also induced a slight tilting of TM1 towards the membrane plane and decreased the size of the channel pore at the gate, which seems to be the major mechanism for the inhibition of spontaneous opening of the double mutant channel. More importantly, the newly identified interaction between the TM2 (Phe78) and adjacent TM1 (Ile32-Leu36-Ile40) helices seems to be an essential force transmitting mechanism for the stretch-dependent activation of MscL given that substitution of any one of these four amino acids with Asn resulted in severe loss-of-function MscL as reported in our previous work.

Diagnostic and therapeutic challenges in a pediatric patient with anencephaly, hydrocephalus and epilepsy: Case report

Introduction: a 5-month-old female patient with an intrauterine diagnosis at 5 months of anencephaly plus hydrocephalus with a poor prognosis. Obtained by caesarean section at term. She stayed 4 days in pediatric intensive care and was then discharged. He attended due to a clinical picture characterized by a convulsive crisis at 7:00 p.m. and 8:00 p.m. She was hospitalized for 22 days presenting macrocephalus, tension hydrocephalus, external ventricular drain in place, gaze at the rising sun, spontaneous eye opening. She is under sedation and analgesia with infusion of midazolam and fentanyl, connected to mechanical ventilation through an endotracheal tube. Case report: present a complex clinical case where the patient presents anencephaly plus hydrocephalus and epilepsy without evidence of cerebral lobes. Conclusion: anencephaly, hydrocephalus and epilepsy are serious neurological conditions, due to the significant impact that can be present in the life of the person suffering from these medical conditions. It is extremely rare that the patient presents epilepsy and each time the episodes are more violent until the loss of consciousness

Tonic Eye-Opening Associated with the «Burst-Suppression» Pattern in Patients with Acute Anoxic Brain Injury (Case Series)

Massive anoxic brain injury caused by cardiac arrest leads to wakefulness suppression up to coma. The prediction of outcome is based on the analysis of the clinical features and the results of instrumental tests. One of the well-known signs of an unfavorable prognosis is involuntary motor activity, which is most commonly represented by myoclonus. In case of their cortical origin, they are accompanied by epileptiform activity in the electroencephalogram (EEG).Material and methods. We present a case series and literature review concerning a very rare fatal sign, non-rhythmic spontaneous eye opening accompanied by a «burst-suppression» pattern (BS) in the EEG. All patients suffered from transient acute hypotension or arrhythmia that required cardiopulmonary resuscitation (CPR) in three cases. A literature search found only 11 publications describing post-anoxic tonic eye-opening (PATEO).Results. The PATEO with BS was observed for less than a day followed by cessation of brain bioelectric activity in all patients. Only two patients exhibited isolated eye-opening and closing, while the rest had axial and limbs myoclonus just after CPR. In one case, eyelid opening was followed by a clonic movement of the head to the right, the EEG bursts were prolonged and had spike-like morphology. Three patients received antiepileptic and sedative therapy. All patients died in 3-43 days after the fatal cardiovascular event.Visual superposition of bursts in EEG and myogram of m. orbicularis oculi demonstrating identical morphology for EEG and myographic bursts was described for the first time. Our cases and literature review confirm that, regardless of the intensive treatment, patients with PATEO have fatal outcomes.Conclusion. The clinical and electrographic PATEO with BS phenomenon always indicates a lethal prognosis. The origin of PATEO is still under discussion. We suggest that it could be caused by disinhibition of subcortical and stem structures during extensive death of cerebral cortical neurons.

Atomistic Picture of Opening-Closing Dynamics of DNA Holliday Junction Obtained by Molecular Simulations.

Holliday junction (HJ) is a noncanonical four-way DNA structure with a prominent role in DNA repair, recombination, and DNA nanotechnology. By rearranging its four arms, HJ can adopt either closed or open state. With enzymes typically recognizing only a single state, acquiring detailed knowledge of the rearrangement process is an important step toward fully understanding the biological function of HJs. Here, we carried out standard all-atom molecular dynamics (MD) simulations of the spontaneous opening-closing transitions, which revealed complex conformational transitions of HJs with an involvement of previously unconsidered "half-closed" intermediates. Detailed free-energy landscapes of the transitions were obtained by sophisticated enhanced sampling simulations. Because the force field overstabilizes the closed conformation of HJs, we developed a system-specific modification which for the first time allows the observation of spontaneous opening-closing HJ transitions in unbiased MD simulations and opens the possibilities for more accurate HJ computational studies of biological processes and nanomaterials.