Controlling the spontaneous spiking regularity via channel blocking on Newman-Watts networks of Hodgkin-Huxley neurons

We investigate the regularity of spontaneous spiking activity on Newman-Watts small-world networks consisting of biophysically realistic Hodgkin-Huxley neurons with a tunable intensity of intrinsic noise and fraction of blocked voltage-gated sodium and potassium ion channels embedded in neuronal membranes. We show that there exists an optimal fraction of shortcut links between physically distant neurons, as well as an optimal intensity of intrinsic noise, which warrant an optimally ordered spontaneous spiking activity. This doubly coherence resonance-like phenomenon depends significantly, and can be controlled via the fraction of closed sodium and potassium ion channels, whereby the impacts can be understood via the analysis of the firing rate function as well as the deterministic system dynamics. Potential biological implications of our findings for information propagation across neural networks are also discussed.Comment: 6 two-column pages, 5 figures; accepted for publication in Europhysics Letter

Add-on therapy with different non-steroidal anti-inflammatory agents in the management of non-infectious, non-necrotizing episcleritis

Background: Episcleritis is a common ocular inflammatory disease that can cause red eye. It is usually managed using single or combined topical corticosteroids and topical or oral non-steroidal anti-inflammatory drugs (NSAIDs) as directed by clinical response. However, recurrence is possible. This study aimed to compare the effects of add-on therapies using different topical NSAIDs in the management of treatment-naive, non-infectious, non-necrotizing episcleritis. Methods: Seventy-five eyes of 75 patients with non-infectious, non-necrotizing unilateral episcleritis were included in this study. Patients were allocated to one of three groups based on the NSAID used as add-on therapy: topical diclofenac sodium 0.1% (group D), topical nepafenac 0.1% (group N1), and topical nepafenac 0.3% (group N3). The time to symptom disappearance was defined as the recovery time.   Results: There were no statistically significant differences in age, sex, initial best-corrected distance visual acuity, and intraocular pressure between groups (all P > 0.05). The mean recovery times of groups D and N1 were comparable (12.86 ± 5.35 days and 11.45 ± 5.42 days, respectively) (P > 0.05). However, the mean recovery time of group N3 was significantly shorter (9.70 ± 3.80 days, P < 0.05). Recurrence was observed in only one patient in group N1 at 3 months, and symptoms resolved when the same medication was reinstituted. Furthermore, we noted no side effects during the follow-up period for any of the treatment modalities.  Conclusions: All three topical NSAIDs were effective add-on therapies in the management of non-infectious, non-necrotizing unilateral episcleritis. However, once-daily administration of topical nepafenac 0.3% had a shorter recovery time than topical diclofenac 0.1% and topical nepafenac 0.1%

Chimera states in hybrid coupled neuron populations

Here we study the emergence of chimera states, a recently reported phenomenon referring to the coexistence of synchronized and unsynchronized dynamical units, in a population of Morris-Lecar neurons which are coupled by both electrical and chemical synapses, constituting a hybrid synaptic architecture, as in actual brain connectivity. This scheme consists of a nonlocal network where the nearest neighbor neurons are coupled by electrical synapses, while the synapses from more distant neurons are of the chemical type. We demonstrate that peculiar dynamical behaviors, including chimera state and traveling wave, exist in such a hybrid coupled neural system, and analyze how the relative abundance of chemical and electrical synapses affects the features of chimera and different synchrony states (i.e. incoherent, traveling wave and coherent) and the regions in the space of relevant parameters for their emergence. Additionally, we show that, when the relative population of chemical synapses increases further, a new intriguing chaotic dynamical behavior appears above the region for chimera states. This is characterized by the coexistence of two distinct synchronized states with different amplitude, and an unsynchronized state, that we denote as a chaotic amplitude chimera. We also discuss about the computational implications of such state. (c) 2020 Elsevier Ltd. All rights reserved.MU acknowledges Bulent Ecevit University Research Foundation, Turkey under Project No. BAP2018-39971044-01. JJT acknowledges the Spanish Ministry for Science and Technology and the "Agencia Espanola de Investigacion, Spain'' (AEI) for financial support under grant FIS2017-84256-P (FEDER funds). AC acknowledges financial support from the Scientific and Technological Research Council of Turkey (TUBITAK) BIDEB-2214/A International Research Fellowship Program, and the hospitality of the Institute Carlos I for Theoretical and Computational Physics at University of Granada

Radiological staging in neuroblastoma : computed tomography or magnetic resonance imaging?

Purpose: To compare the effectiveness of computed tomography (CT) and magnetic resonance imaging (MRI) in the staging of neuroblastomas according to the International Neuroblastoma Risk Group Staging System (INRGSS). Material and methods: In this single-centre retrospective study we identified a total of 20 patients under the age of 18 years, who were admitted to our hospital with neuroblastoma between January 2005 and May 2018, and who had both CT and MRI examination. The INRGSS stages of tumours were evaluated by CT scan and MRI. Then, stages of tumours were described according to the INRGSS for CT and MRI, separately. The Spearman rank correlation test was used for statistical analysis. The p-value < 0.05 was considered as statistically significant. Results: The median age was 11 months, and the age range was one month to nine years. In our results; both MRI and CT were significant in the determination of radiological staging of NBL, p < 0.001 and p = 0.002, respectively. MRI was superior to CT in radiological staging. MRI was also superior for the detection of intraspinal extension, involvement of multiple body compartments, metastatic disease, and bone marrow infiltration. CT was more useful to consider the relationship between tumours and vascular structures. Conclusions: MRI and CT have high diagnostic accuracy rates in the staging of pre-treatment neuroblastomas. MRI is important in pre-treatment evaluation of neuroblastomas because of the higher detection of metastases as well as the lack of ionising radiation

Thoracic Cavernoma with Intraosseous and Extradural Component Mimicking Metastasis: Case presentation

Spinal epidural cavernomas are quite rare lesions and only 5% of all cavernomas are located in the spine. The lesions are most commonly localized in the thoracic region. The differential diagnosis includes neurogenic tumors, lymphoma, schwannoma, meningioma, multiple myeloma, Ewing's sarcoma and metastasis. A 40-year-old male patient presented with paraplegia and MR images revealed an epidural soft tissue constricting the right posterolateral of the cord at the T6 level. Pathology showed cavernous hemangioma. A literature search revealed no other case that so closely mimicked metastasis by invading all components of the thoracic vertebra and also expanding to the epidural distance. We therefore present the case emphasizing these features

Vibrational resonance in a scale-free network with different coupling schemes

We investigate the phenomenon of vibrational resonance (VR) in neural populations, whereby weak low-frequency signals below the excitability threshold can be detected with the help of additional high-frequency driving. The considered dynamical elements consist of excitable FitzHugh–Nagumo neurons connected by electrical gap junctions and chemical synapses. The VR performance of these populations is studied in unweighted and weighted scale-free networks. We find that although the characteristic network features – coupling strength and average degree – do not dramatically affect the signal detection quality in unweighted electrically coupled neural populations, they have a strong influence on the required energy level of the high-frequency driving force. On the other hand, we observe that unweighted chemically coupled populations exhibit the opposite behavior, and the VR performance is significantly affected by these network features whereas the required energy remains on a comparable level. Furthermore, we show that the observed VR performance for unweighted networks can be either enhanced or worsened by degree-dependent coupling weights depending on the amount of heterogeneity

Technical Aspects and Clinical Limitations of Sperm DNA Fragmentation Testing in Male Infertility: A Global Survey, Current Guidelines, and Expert Recommendations

PURPOSE: Sperm DNA fragmentation (SDF) is a functional sperm abnormality that can impact reproductive potential, for which four assays have been described in the recently published sixth edition of the WHO laboratory manual for the examination and processing of human semen. The purpose of this study was to examine the global practices related to the use of SDF assays and investigate the barriers and limitations that clinicians face in incorporating these tests into their practice. MATERIALS AND METHODS: Clinicians managing male infertility were invited to complete an online survey on practices related to SDF diagnostic and treatment approaches. Their responses related to the technical aspects of SDF testing, current professional society guidelines, and the literature were used to generate expert recommendations via the Delphi method. Finally, challenges related to SDF that the clinicians encounter in their daily practice were captured. RESULTS: The survey was completed by 436 reproductive clinicians. Overall, terminal deoxynucleotidyl transferase deoxyuridine triphosphate Nick-End Labeling (TUNEL) is the most commonly used assay chosen by 28.6%, followed by the sperm chromatin structure assay (24.1%), and the sperm chromatin dispersion (19.1%). The choice of the assay was largely influenced by availability (70% of respondents). A threshold of 30% was the most selected cut-off value for elevated SDF by 33.7% of clinicians. Of respondents, 53.6% recommend SDF testing after 3 to 5 days of abstinence. Although 75.3% believe SDF testing can provide an explanation for many unknown causes of infertility, the main limiting factors selected by respondents are a lack of professional society guideline recommendations (62.7%) and an absence of globally accepted references for SDF interpretation (50.3%). CONCLUSIONS: This study represents the largest global survey on the technical aspects of SDF testing as well as the barriers encountered by clinicians. Unified global recommendations regarding clinician implementation and standard laboratory interpretation of SDF testing are crucial

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P &lt; 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Controversy and Consensus on Indications for Sperm DNA Fragmentation Testing in Male Infertility: A Global Survey, Current Guidelines, and Expert Recommendations

Purpose: Sperm DNA fragmentation (SDF) testing was recently added to the sixth edition of the World Health Organization laboratory manual for the examination and processing of human semen. Many conditions and risk factors have been associated with elevated SDF; therefore, it is important to identify the population of infertile men who might benefit from this test. The purpose of this study was to investigate global practices related to indications for SDF testing, compare the relevant professional society guideline recommendations, and provide expert recommendations. Materials and Methods: Clinicians managing male infertility were invited to take part in a global online survey on SDF clinical practices. This was conducted following the CHERRIES checklist criteria. The responses were compared to professional society guideline recommendations related to SDF and the appropriate available evidence. Expert recommendations on indications for SDF testing were then formulated, and the Delphi method was used to reach consensus. Results: The survey was completed by 436 experts from 55 countries. Almost 75% of respondents test for SDF in all or some men with unexplained or idiopathic infertility, 39% order it routinely in the work-up of recurrent pregnancy loss (RPL), and 62.2% investigate SDF in smokers. While 47% of reproductive urologists test SDF to support the decision for varicocele repair surgery when conventional semen parameters are normal, significantly fewer general urologists (23%; p=0.008) do the same. Nearly 70% would assess SDF before assisted reproductive technologies (ART), either always or for certain conditions. Recurrent ART failure is a common indication for SDF testing. Very few society recommendations were found regarding SDF testing. Conclusions: This article presents the largest global survey on the indications for SDF testing in infertile men, and demonstrates diverse practices. Furthermore, it highlights the paucity of professional society guideline recommendations. Expert recommendations are proposed to help guide clinicians