Hybrid Tamm and quasi-BIC microcavity modes.

The microcavity in the form of a liquid crystal defect layer embedded in a one-dimensional photonic crystal is considered. The microcavity mode has a tunable radiation decay rate in the vicinity of a bound state in the continuum. It is demonstrated that coupling between the microcavity mode and a Tamm plasmon polariton results in hybrid Tamm-microcavity modes with a tunable Q factor. The measured spectral features of hybrid modes are explained in the framework of the temporal coupled mode theory.

[Issues of legal responsibility of the pathologist]. / Voprosy yuridicheskoi otvetstvennosti patologoanatoma.

Medical care refers to a risky type of activity, since as a result of its provision, harm to the patient's health may be caused and prerequisites for the onset of legal (civil, disciplinary, administrative and criminal) liability may arise. The legal liability of a pathologist in the event of an incorrect diagnosis by the attending physician on the basis of an incorrect conclusion of the pathologist may occur due to violations due to low qualifications, frivolity, negligence, failure to comply with the rules, procedures for providing medical care, job descriptions, official duties. If the incorrect conclusion of the pathologist was of an objective nature (for example, in the case of an incorrect interpretation of a diagnostically difficult case), it should go beyond the scope of punishable shortcomings in the activities of the pathologist. The financial responsibility of a pathologist may occur when its burden is placed on a medical organization for harm caused to the life or health of a patient, due to the establishment, among other things, of the legality of the actions (inaction) of a medical worker with whom the medical organization is in an employment relationship. A medical organization, in case of satisfaction of the patient's claims by the court, as a rule, in a regression procedure, may involve the relevant medical worker who caused the harm in the issue of compensation, compensate for their financial and reputational losses. The most important thing in such cases is to resolve the issue of establishing the grounds for bringing a medical worker to responsibility.

Towards a core outcome set for cranioplasty following traumatic brain injury and stroke 'A systematic review of reported outcomes'.

Background: There is wide-ranging published literature around cranioplasty following traumatic brain injury (TBI) and stroke, but the heterogeneity of outcomes limits the ability for meta-analysis. Consensus on appropriate outcome measures has not been reached, and given the clinical and research interest, a core outcome set (COS) would be beneficial. Objectives: To collate outcomes currently reported across the cranioplasty literature which will subsequently be used in developing a cranioplasty COS. Methods: This systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. All full-text English studies with more than ten patients (prospective) or more than 20 patients (retrospective) published after 1990 examining outcomes in CP were eligible for inclusion. Results: The review included 205 studies from which 202 verbatim outcomes were extracted, grouped into 52 domains, and categorised into one or more of the OMERACT 2.0 framework core area(s). The total numbers of studies that reported outcomes in the core areas are 192 (94%) pathophysiological manifestations/ 114 (56%) resource use/economic impact/ 94 (46%) life impact/mortality 20 (10%). In addition, there are 61 outcome measures used in the 205 studies across all domains. Conclusion: This study shows considerable heterogeneity in the types of outcomes used across the cranioplasty literature, demonstrating the importance and necessity of developing a COS to help standardise reporting across the literature.

Voltage-tunable Q factor in a photonic crystal microcavity.

A photonic crystal microcavity with a tunable quality factor (Q factor) has been implemented on the basis of a bound state in the continuum using the advanced liquid crystal cell technology platform. It has been shown that the Q factor of the microcavity changes from 100 to 360 in the voltage range of 0.6 V.

Cranioplasty: A Multidisciplinary Approach.

Decompressive craniectomy (DC) is an operation where a large section of the skull is removed to accommodate brain swelling. Patients who survive will usually require subsequent reconstruction of the skull using either their own bone or an artificial prosthesis, known as cranioplasty. Cranioplasty restores skull integrity but can also improve neurological function. Standard care following DC consists of the performance of cranioplasty several months later as historically, there was a concern that earlier cranioplasty may increase the risk of infection. However, recent systematic reviews have challenged this and have demonstrated that an early cranioplasty (within three months after DC) may enhance neurological recovery. However, patients are often transferred to a rehabilitation unit following their acute index admission and before their cranioplasty. A better understanding of the pathophysiological effects of cranioplasty and the relationship of timing and complications would enable more focused patient tailored rehabilitation programs, thus maximizing the benefit following cranioplasty. This may maximise recovery potential, possibly resulting in improved functional and cognitive gains, enhancement of quality of life and potentially reducing longer-term care needs. This narrative review aims to update multi-disciplinary team regarding cranioplasty, including its history, pathophysiological consequences on recovery, complications, and important clinical considerations both in the acute and rehabilitation settings.

Electric field-controlled transformation of the eigenmodes in a twisted-nematic Fabry-Pérot cavity.

The polarized optical states in the transmission spectrum of a twisted-nematic Fabry-Pérot cavity with the distinctly broken Mauguin's waveguide regime have been theoretically and experimentally investigated. Specific features of the electric field-induced transformation of the polarization and spectral characteristics of eigenmodes of the neighboring series at the overlap resonant frequencies have been examined. It is demonstrated that the linear polarizations of eigenmodes at the cavity boundaries remain nearly orthogonal and their frequency trajectories reproduce the avoided crossing phenomenon. The experimental data are confirmed analytically and by the numerical simulation of light transmission through the investigated anisotropic multilayer with the use of a Berreman matrix method. The results obtained can be generalized to any materials with the helix response.

[The role and place of pathology services in ensuring and improving the quality of medical care: Organizational and legal aspects].

The paper considers the legal and organizational issues of the activity of pathology services in improving medical care. It shows the main (diagnostic and medico-organizational) areas of pathology work to improve the quality of medical care.

Changes in long-range connectivity and neuronal reorganization in partial cortical deafferentation model of epileptogenesis.

Severe brain injuries can trigger epileptogenesis, a latent period that eventually leads to epilepsy. Previous studies have demonstrated that changes in local connectivity between cortical neurons are a part of the epileptogenic processes. In the present study we aimed to investigate whether changes in long-range connectivity are also involved in epileptogenesis. We performed a large unilateral transection (undercut) of the white matter below the suprasylvian gyrus in cats. After about 2 months, we either injected retrograde tracer (cholera toxin, sub-unit B, CTB) or performed Golgi staining. We analyzed distribution of retrogradely labeled neurons, counted dendritic spines in the neocortex (Golgi staining), and analyzed dendritic orientation in control conditions and after the injury. We found a significant increase in the number of detected cells at the frontal parts of the injured hemisphere, which suggests that the process of axonal sprouting occurs in the deafferented area. The increase in the number of retrogradely stained neurons was accompanied with a significant decrease in neocortical spine density in the undercut area, a reduction in vertical and an increase in horizontal orientation of neuronal processes. The present study shows global morphological changes underlying epileptogenesis. An increased connectivity in the injured cortical regions accompanied with a decrease in spine density suggests that excitatory synapses might be formed on dendritic shafts, which probably contributes to the altered neuronal excitability that was described in previous studies on epileptogenesis.

Surface modes in "photonic cholesteric liquid crystal-phase plate-metal" structure.

The light transmission spectrum has been calculated for a "cholesteric liquid crystal-phase plate-metal" structure. It is shown that the system can have an isolated waveguide surface mode with characteristics efficiently controllable by external fields acting on the cholesteric. The degree of localization of surface modes and the transmission coefficients have been found to differ considerably for the light of different polarizations.

Decompressive craniectomy - operative technique and perioperative care.

With improvements in neurocritical care advanced measures of treating raised intracranial pressure (ICP) are more frequently utilised. Decompressive craniectomy is an effective ICP-lowering procedure; however its benefits are maximised with optimal surgical technique and perioperative care, as well as by paying attention to possible complications. This article focuses on the current indications and rationale for decompressive craniectomy, and the surgical technique of bifrontal and unilateral decompression. The key surgical points include a large craniectomy window and opening of the dura, leaving it unsutured or performing a wide non-constricting duroplasty. Perioperative care and possible complications are also discussed.

[Use of sunitinib in metastatic renal cell carcinoma patients with poor prognosis].

We evaluated overall and relapse-free survival in patients with metastatic renal cell carcinoma (MRCC) with poor prognosis. The study involved 92 patients (median age 54.1 years, male 63%, female 29%), retrospectively; 48.9% had poor prognosis. They received oral sunitinib 59 mg/day in 6 cycles (4 weeks on, 2 weeks off). Median overall survival was 17.6 months, relapse-free--10.8 months. Risk of progression in the poor and good prognosis groups was identical (HR=09). Overall response was 29% in poor prognosis and 40%--in good one (p = 0.07). Drug tolerability was acceptable in both groups. Sunitinib was effective in both groups of MRCC patients.

Effect of synaptic connectivity on long-range synchronization of fast cortical oscillations.

Cortical gamma oscillations in the 20- to 80-Hz range are associated with attentiveness and sensory perception and have strong connections to both cognitive processing and temporal binding of sensory stimuli. These gamma oscillations become synchronized within a few milliseconds over distances spanning a few millimeters in spite of synaptic delays. In this study using in vivo recordings and large-scale cortical network models, we reveal a critical role played by the network geometry in achieving precise long-range synchronization in the gamma frequency band. Our results indicate that the presence of many independent synaptic pathways in a two-dimensional network facilitate precise phase synchronization of fast gamma band oscillations with nearly zero phase delays between remote network sites. These findings predict a common mechanism of precise oscillatory synchronization in neuronal networks.

Ventriculostomy for control of raised ICP in acute traumatic brain injury.

UNLABELLED: The aim of this study was to evaluate the effect of ventriculostomy on intracranial pressure (ICP), and related parameters, including cerebrospinal compensation, cerebral oxygenation (PbtO2) and metabolism (microdialysis) in patients with traumatic brain injury (TBI). MATERIALS AND METHODS: Twenty-four patients with parenchymal ICP sensors were prospectively included in the study. Ventriculostomy was performed after failure to control ICP with initial measures. Monitoring parameters were digitally recorded before and after ventriculostomy and compared using appropriate tests. RESULTS: In all patients ventriculostomy led to rapid reduction in ICP. Pooled mean daily values of ICP remained < 20mmHg for 72h after ventriculostomy and were lower than before (p < 0.001). In 11 out of 24 patients during the initial 24-h period following ventriculostomy an increase in ICP to values exceeding 20mmHg was observed. In the remaining 13 patients ICP remained stable, allowing reduction in the intensity of treatment. In this group ventriculostomy led to significant improvement in craniospinal compensation (RAP index), cerebral perfusion pressure and PbtO2. Improvement in lactate/pyruvate ratio, a marker of energy metabolism, was correlated with the increase in PbtO2. CONCLUSION: Ventriculostomy is a useful ICP-lowering manoeuvre, with sustained ICP reduction and related physiological improvements achieved in > 50% of patients.

ICM+, a flexible platform for investigations of cerebrospinal dynamics in clinical practice.

BACKGROUND: ICM+ software encapsulates 20 years of our experience in brain monitoring gained in multiple neurosurgical and intensive care centres. It collects data from a variety of bedside monitors and produces on-line time trends of parameters defined using configurable signal processing formulas. The resulting data can be displayed in a variety of ways including time trends, histograms, cross histograms, correlations, etc. For technically minded researchers there is a plug-in mechanism facilitating registration of third party libraries of functions and analysis tools. METHODS: The latest version of the ICM+ software has been used in 162 severely head injured patients in the Neurosciences Critical Care Unit of the Addenbrooke's Cambridge University Hospital. Intracranial pressure (ICP) and invasive arterial blood pressure (ABP) were monitored routinely. Mean values of ICP, ABP, cerebral perfusion pressure (CPP) and various indices describing pressure reactivity (PRx), pressure-volume compensation (RAP) and vascular waveforms of ICP were calculated. Error-bar chart showing reactivity index PRx versus CPP ('Optimal CPP' chart) was calculated continuously. FINDINGS: PRx showed a significant relationship with CPP (ANOVA: p < 0.021) indicating loss of cerebral pressure-reactivity for low CPP (CPP < 55 mmHg) and for high CPPs (CPP > 95 mmHg). Examining PRx-CPP curves in individual patients revealed that CPP(OPT) not only varied between subjects but tended to fluctuate as the patient's state changed during the stay in the ICU. Calculation window of 6-8 h provided enough data to capture the CPP(OPT) curve. CONCLUSIONS: ICM+ software proved to be useful both academically and clinically. The complexity of data analysis is hidden inside loadable profiles thus allowing clinically minded investigators to take full advantage of signal processing engine in their research into cerebral blood and fluid dynamics.

Cerebrovascular reactivity during hypothermia and rewarming.

BACKGROUND: Experimental evidence from a murine model of traumatic brain injury (TBI) suggests that hypothermia followed by fast rewarming may damage cerebral microcirculation. The effects of hypothermia and subsequent rewarming on cerebral vasoreactivity in human TBI are unknown. METHODS: This is a retrospective analysis of data acquired during a prospective, observational neuromonitoring and imaging data collection project. Brain temperature, intracranial pressure (ICP), and cerebrovascular pressure reactivity index (PRx) were continuously monitored. RESULTS: Twenty-four TBI patients with refractory intracranial hypertension were cooled from 36.0 (0.9) to 34.2 (0.5) degrees C [mean (sd), P < 0.0001] in 3.9 (3.7) h. Induction of hypothermia [average duration 40 (45) h] significantly reduced ICP from 23.1 (3.6) to 18.3 (4.8) mm Hg (P < 0.05). Hypothermia did not impair cerebral vasoreactivity as average PRx changed non-significantly from 0.00 (0.21) to -0.01 (0.21). Slow rewarming up to 37.0 degrees C [rate of rewarming, 0.2 (0.2) degrees C h(-1)] did not increase ICP [18.6 (6.2) mm Hg] or PRx [0.06 (0.18)]. However, in 17 (70.1%) out of 24 patients, rewarming exceeded the brain temperature threshold of 37 degrees C. In these patients, the average brain temperature was allowed to increase to 37.8 (0.3) degrees C (P < 0.0001), ICP remained stable at 18.3 (8.0) mm Hg (P = 0.74), but average PRx increased to 0.32 (0.24) (P < 0.0001), indicating significant derangement in cerebrovascular reactivity. After rewarming, PRx correlated independently with brain temperature (R = 0.53; P < 0.05) and brain tissue O2 (R = 0.66; P < 0.01). CONCLUSIONS: After moderate hypothermia, rewarming exceeding the 37 degrees C threshold is associated with a significant increase in average PRx, indicating temperature-dependent hyperaemic derangement of cerebrovascular reactivity.

Callosal responses of fast-rhythmic-bursting neurons during slow oscillation in cats.

The cortically generated slow oscillation consists of long-lasting hyperpolarizations associated with depth-positive electroencephalogram (EEG) waves and neuronal depolarizations accompanied by firing during the depth-negative EEG waves. It has previously been shown that, during the prolonged hyperpolarizations, the transfer of information from prethalamic pathways to neocortex is impaired, whereas the intracortical dialogue is maintained. To study some of the factors that may account for the maintenance of the intracortical information transfer during the hyperpolarization, intracellular recordings from association areas 5 and 7 were performed in anesthetized cats, and the synaptic responsiveness of fast-rhythmic-bursting, regular-spiking and fast-spiking neurons was tested using single pulses to the homotopic sites in the contralateral areas. During the long-lasting hyperpolarizations callosal volleys elicited in fast-rhythmic-bursting neurons, but not in regular-spiking or fast-spiking neurons, large-amplitude excitatory post-synaptic potentials crowned by single action potentials or spike clusters. Our data show that callosal volleys excite and lead to spiking in fast-rhythmic-bursting neurons during prolonged hyperpolarizations, thus enabling them to transmit information within intracortical networks during slow-wave sleep.

Mircea Steriade (1924-2006).

Dr. Mircea Steriade passed away at age 82. In this obituary I briefly describe some of the most important achievements of his remarkable life and I express deepest sympathies to his family members, collaborators and trainees.

Outcome after surgical decompression of severe traumatic brain injury.

One of the factors that affects outcome following severe traumatic brain injury is development and progression of cerebral oedema with associated increase in intracranial pressure (ICP). Uncontrolled elevations of ICP may compromise energy metabolism of the injured brain and lead to secondary injury, affecting neurological outcome of the patient. Decompressive craniectomy has been used for over a century as a treatment of refractory brain swelling in a variety of neurological conditions. However, conclusive evidence of whether it has a beneficial or adverse affect on outcome is lacking. This article reviews the existing evidence on the role of decompressive craniectomy in management of patients with traumatic brain injury and stresses the need for randomised controlled trials.

Decompressive craniectomy in traumatic brain injury: outcome following protocol-driven therapy.

Although decompressive craniectomy following traumatic brain injury is an option in patients with raised intracranial pressure (ICP) refractory to medical measures, its effect on clinical outcome remains unclear. The aim of this study was to evaluate the outcome of patients undergoing this procedure as part of protocol-driven therapy between 2000-2003. This was an observational study combining case note analysis and follow-up. Outcome was assessed at an interval of at least 6 months following injury using the Glasgow Outcome Scale (GOS) score and the SF-36 quality of life questionnaire. Forty-nine patients underwent decompressive craniectomy for raised and refractory ICP (41 [83.7%] bilateral craniectomy and 8 [16.3%] unilateral). Using the Glasgow Coma Scale (GCS), the presenting head injury grade was severe (GCS 3-8) in 40 (81.6%) patients, moderate (GCS 9-12) in 8 (16.3%) patients, and initially mild (GCS 13-15) in 1 (2.0%) patient. At follow-up, 30 (61.2%) patients had a favorable outcome (good recovery or moderate disability), 10 (20.48) remained severely disabled, and 9 (18.4%) died. No patients were left in a vegetative state. Overall the results demonstrated that decompressive craniectomy, when applied as part of protocol-driven therapy, yields a satisfactory rate of favorable outcome. Formal prospective randomized studies of decompressive craniectomy are now indicated.

Decompressive craniectomy in traumatic brain injury: the randomized multicenter RESCUEicp study (www.RESCUEicp.com).

The RESCUEicp (Randomized Evaluation of Surgery with Craniectomy for Uncontrollable Elevation of intracranial pressure) study has been established to determine whether decompressive craniectomy has a role in the management of patients with traumatic brain injury and raised intracranial pressure that does not respond to initial treatment measures. We describe the concept of decompressive craniectomy in traumatic brain injury and the rationale and protocol of the RESCUEicp study.