Cooperation dynamics in dynamical networks with history-based decisions

In many aspects of life on earth, individuals may engage in cooperation with others to contribute towards a goal they may share, which can also ensure self-preservation. In evolutionary game theory, the act of cooperation can be considered as an altruistic act of an individual producing some form of benefit or commodity that can be utilised by others they are associated with, which comes at some personal cost. Under certain conditions, individuals make use of information that they are able to perceive within a group in order to aid with their choices for who they should associate themselves within these cooperative scenarios. However, cooperative individuals can be taken advantage of by opportunistic defectors, which can cause significant disruption to the population. We study a model where the decision to establish interactions with potential partners is based on the opportune integration of the individual’s private ability to perceive the intentions of others (private information) and the observation of the population, information that is available to every individual (public information). When public information is restricted to a potential partners current connection count, the population becomes highly cooperative but rather unstable with frequent invasions of cheaters and recoveries of cooperation. However, when public information considers the previous decisions of the individuals (accepted / rejected connections) the population is slightly less cooperative but more stable. Generally, we find that allowing the observation of previous decisions, as part of the available public information, can often lead to more stable but fragmented and less prosperous networks. Our results highlight that the ability to observe previous individual decisions, balanced by individuals personal information, represents an important aspect of the interplay between individual decision-making and the resilience of cooperation in structured populations.

Compositional modelling of immune response and virus transmission dynamics

Transmission models for infectious diseases are typically formulated in terms of dynamics between individuals or groups with processes such as disease progression or recovery for each individual captured phenomenologically, without reference to underlying biological processes. Furthermore, the construction of these models is often monolithic: they do not allow one to readily modify the processes involved or include the new ones, or to combine models at different scales. We show how to construct a simple model of immune response to a respiratory virus and a model of transmission using an easily modifiable set of rules allowing further refining and merging the two models together. The immune response model reproduces the expected response curve of PCR testing for COVID-19 and implies a long-tailed distribution of infectiousness reflective of individual heterogeneity. This immune response model, when combined with a transmission model, reproduces the previously reported shift in the population distribution of viral loads along an epidemic trajectory. This article is part of the theme issue 'Technical challenges of modelling real-life epidemics and examples of overcoming these'.

Surgical Management of Intractable Meniere's Disease

Meniere's Disease (MD) is an inner ear disorder characterized by spontaneous recurrent vertigo, fluctuating sensorineural hearing loss, aural fullness and low-pitch tinnitus. Therapeutic management of MD includes dietary restriction and medical therapy. A minority of cases is characterized by frequent vertigo attacks, progressive hearing loss and persistent tinnitus even through the continuous medical treatments; this condition is called intractable MD and requires a therapeutic escalation from non-invasive medical treatment to surgical intervention. Invasive procedures include endolymphatic sac surgery, vestibular nerve section and labyrinthectomy. These procedures have a very high success rate on symptom control but may have a severe impact on the hearing function. However, the simultaneous combined approach of demolitive surgery and cochlear implantation may be a valid approach to treat symptoms of intractable MD and preserve hearing function. In the present study, we review current literature focusing on intractable MD to describe and discuss advantages and disadvantages of established and newly proposed surgical treatments for intractable MD.

Rule-based epidemic models

Rule-based models generalise reaction-based models with reagents that have internal state and may be bound together to form complexes, as in chemistry. An important class of system that would be intractable if expressed as reactions or ordinary differential equations can be efficiently simulated when expressed as rules. In this paper we demonstrate the utility of the rule-based approach for epidemiological modelling presenting a suite of seven models illustrating the spread of infectious disease under different scenarios: wearing masks, infection via fomites and prevention by hand-washing, the concept of vector-borne diseases, testing and contact tracing interventions, disease propagation within motif-structured populations with shared environments such as schools, and superspreading events. Rule-based models allow to combine transparent modelling approach with scalability and compositionality and therefore can facilitate the study of aspects of infectious disease propagation in a richer context than would otherwise be feasible.

Assessing the ecological quality status of the highly polluted Bagnoli area (Tyrrhenian Sea, Italy) using foraminiferal eDNA metabarcoding

Morphology-based benthic foraminifera indices are increasingly used worldwide for biomonitoring the ecological quality of marine sediments. The recent development of foraminiferal eDNA metabarcoding offers a reliable, time-, and cost-effective alternative to morphology-based foraminiferal biomonitoring. However, the practical applications of these new tools are still highly limited. In the present study, we evaluate the response of benthic foraminifera and define the ecological quality status (EcoQS) in the Bagnoli area (Tyrrhenian Sea, Italy) based on a traditional morphology-based approach and eDNA metabarcoding. The geochemical data show that several sites in front of the former industrial plant contain higher concentrations of potentially toxic elements than the effect range median and are characterized by the highest total organic carbon (TOC) content, whereas the distantly located sites can be considered relatively low- to unpolluted. Significant differences (i.e., diversity and assemblage composition) in both morphological and molecular datasets were found between the relatively low- to unpolluted and the most polluted areas. Similarly, the selected ecological indices of both morphological and molecular datasets strikingly and congruently resulted in a clear separation following the environmental stress gradient. The molecular indices (i.e., g-exp(H'_bc), g-Foram AMBI, and g-Foram AMBI-MOTUs) reliably identified poor-to-bad EcoQS in the polluted area in front of the former industrial plant. On the other hand, the Foram-AMBI based on morphology well identified an overall trend but seemed to overestimate the EcoQS if the traditional class boundaries were considered. The congruent and complementary trends between morphological and metabarcoding data observed in the case of the Bagnoli site further support the application of foraminiferal metabarcoding in routine biomonitoring to assess the environmental impacts of heavily polluted marine areas.

Partial intracapsular tonsillectomy in the treatment of pediatric obstructive sleep apnea/hypopnea syndrome: a prospective study with 5-year follow-up

Objective

To assess efficacy and safety of tonsil reduction with bipolar forceps electrocautery as treatment of paediatric obstructive sleep apnea/hypopnea syndrome (OSAHS).

Study design

Prospective interventional study.

Methods

Two hundred and sixty-three children aged 4–10 years with OSAHS and an apnea hypopnea index (AHI) > 3 were enrolled from March 2013 to January 2016. Pre-operative evaluation included oropharyngeal clinical examination with fiberoptic nasopharyngoscopy, OSA-18 questionnaire and overnight sleep study. All children were treated with adenoidectomy and tonsillotomy with bipolar forceps. OSA-18 questionnaire and overnight sleep study were performed 30 days after surgery.

Results

Pre-operative average of the OSA-18 questionnaires was of 70.3 (SD = 9.7); 30-day post-operative score was 23.15 (SD = 8.2; p = 0.045). Pre-operative average Apnea Hypopnea Index (AHI) score was 9.41 (SD = 4.1); 30-day post-operative average of AHI score was of 1.75 (SD = 0.8; p = 0.012). Oxygen Desaturation Index (ODI) rate changed from 7.39 (SD = 4) to 1.34 (30-day post-operative) (SD = 4.7; p = 0.085). NADIR rate changed from 79% (SD = 6.32) to 90% (30-day post-operative) (SD = 5.18; p = 0.00012). Peri- and post-operative complications in our sample were mainly pain (average 75 doses of paracetamol), while bleeding did not occur (0%). All patients received a follow-up examination 5 years after surgery to evaluate tonsil size; at this time-point, a reduction in tonsil size from 3.6 (3–4; SD = 4.2) to 1.3 (1–2; SD = 5.5) was found, while tonsil regrowth was observed in five children (2%).

Conclusion

This study showed that partial tonsillotomy with bipolar forceps electrocautery associated to adenoidectomy is an effective technique in treating OSAHS symptoms in children and ensures less complications in terms of hemorrhage, postoperative pain and infections compared to traditional adenotonsillectomy. The very low tonsillar regrowth rate reported in this study may support the routine use of this technique.

Quantification of cell behaviors and computational modeling show that cell directional behaviors drive zebrafish pectoral fin morphogenesis

MOTIVATION

Understanding the mechanisms by which the zebrafish pectoral fin develops is expected to produce insights on how vertebrate limbs grow from a 2D cell layer to a 3D structure. Two mechanisms have been proposed to drive limb morphogenesis in tetrapods: a growth-based morphogenesis with a higher proliferation rate at the distal tip of the limb bud than at the proximal side, and directed cell behaviors that include elongation, division and migration in a non-random manner. Based on quantitative experimental biological data at the level of individual cells in the whole developing organ, we test the conditions for the dynamics of pectoral fin early morphogenesis.

RESULTS

We found that during the development of the zebrafish pectoral fin, cells have a preferential elongation axis that gradually aligns along the proximodistal (PD) axis of the organ. Based on these quantitative observations, we build a center-based cell model enhanced with a polarity term and cell proliferation to simulate fin growth. Our simulations resulted in 3D fins similar in shape to the observed ones, suggesting that the existence of a preferential axis of cell polarization is essential to drive fin morphogenesis in zebrafish, as observed in the development of limbs in the mouse, but distal tip-based expansion is not.

AVAILABILITYAND IMPLEMENTATION

Upon publication, biological data will be available at http://bioemergences.eu/modelingFin, and source code at https://github.com/guijoe/MaSoFin.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Evaluation of Discomfort in Nasopharyngeal Swab Specimen Collection for SARS-CoV-2 Diagnosis

Background

The rapid spread of COVID-19 worldwide has impo-sed the need to identify a test that quickly recognizes affected subjects, both symptomatic and asymptomatic. The most reliable option has been proven to be the RT-PCR, which allows to detect virus RNA on a specimen from a high viral load site, such as nasopharynx. Nasopha-ryngeal sample collection is possible by means of a nasopharyngeal swab (NPS) and is a practical and relatively non-invasive technique, but rather bothersome for the recipient.

Aim

The aim of the present study is to evaluate the discomfort evoked during NPS.

Materials and Methods

We surveyed 429 patients receiving NPS before hospitalization or other procedures non related to COVID-19. For each one we noted the discomfort level felt during the swab using a 11-point numeric rating scale (NRS) for pain and the total time needed for the procedure to be taken. Sex, age, smoking status and positive history of previous swab have been taken into account.

Results

We found that, among the variables, sex had a statistically significant impact on the perceived discomfort of nasal swab, with females experiencing slightly more discomfort.

Conclusions

NPS is largely a none-to-minimum discomfort in-ducing procedure. The differences in perceived discomfort could be explained based on anatomical features, and should remark the need for a tailored and anatomy-oriented approach in each patient.

Inner Ear Disorders in SCUBA Divers: A Review

Self-Contained Underwater Breathing Apparatus (SCUBA) diving is a popular sport. However, improper diving may injure different organs. The majority of dive-related disorders concern otolaryngology, and may include hearing loss, tinnitus, aural fullness, disequilibrium, and vertigo. Three main inner ear pathological conditions can occur underwater: inner ear barotrauma (IEB), inner ear decompression sickness (IEDS), and alternobaric vertigo (AV). IEB results from inappropriate equalization of middle ear pressure and consequent inner ear injury produced by pressure changes within the middle ear; IEDS is characterized by the formation of gas bubbles within the vessels of the inner ear during rapid ascent; AV typically develops while ascending or performing the Valsalva maneuver and can follow asymmetrical equalization of middle ear pressure transmitted via the oval and round window membranes. The clinical pictures of these pathological conditions are partly superimposable, even if they have specific peculiarities. Before starting SCUBA diving, a fit-to-dive assessment is recommended. It should include an otolaryngologic examination with audiological assessment to evaluate nasal, middle ear, and tubal patency and to minimize the risk of IEB, IEDS, and AV. It is of utmost importance to identify individual risk factors and predisposing pathological conditions that favor inner ear injury before diving, to prevent acute events and preserve auditory and vestibular functions in SCUBA divers. This review aims to provide an overview of the pathological conditions characterized by inner ear injury in SCUBA divers, discussing their pathogenetic mechanisms, diagnostic work-up, and prevention.

Chloroquine and hydroxychloroquine ototoxicity; potential implications for SARS-CoV-2 treatment. A brief review of the literature

Introduction

Current clinical evidences do not support any specific treatment against SARS-CoV-2. Chloroquine (CQ) and hydroxychloroquine (HCQ) are typically used in the treatment of rheumatoid arthritis, systemic lupus erythematosus and malaria; they have been considered for off-label and compassionate use in several countries against moderate to severe cases of COVID-19 and there's actually a massive demand of these two drugs. The aim of this paper is to briefly review the published literature, summarizing evidences about audiological implications after CQ and HCQ treatment.

Methods

We conducted a review of the literature on Medline and Pubmed platforms from 27th May 2020 to 30 May 2020. We combined MeSH terms of “chloroquine”, “hydroxychloroquine”, “ototoxicity”, “hearing loss”, “tinnitus”, “deafness” and “hearing”. Publications with relevant data were included. Selected data (authors, country and year; sample size; study design; audiological side effects) were extracted and summarized in a table.

Results

Of 45 initial studies, 14 met inclusion criteria. The authors found xix cases of HCQ ototoxicity; Tinnitus was reported in 2 cases, and it was found to be reversible or irreversible. Sensorineural hearing loss after HCQ use was reported in 7 patients; it was found to be irreversible or partially reversible after discontinuation of HCQ in 6 cases. Eight papers reporting CQ ototoxicity were; tinnitus was not reported by any authors. Sensorineural hearing loss after taking CQ was reported in 6 patients; it was found to be irreversible after discontinuation of CQ in 5 patients. One patient showed abnormal gait after a single intramuscular injection of CQ. Thirteen patients' Auditory Brainstem Response (ABR) were found to be abnormal, but they resolved after CQ discontinuation.

Conclusions

CQ and HCQ related ototoxicity is widely reported in the literature although the pathophysiological mechanism is not well known. Current data are not sufficient enough to support the use of CQ and HCQ as therapy for COVID-19, but considering the growing demand for these two drugs and the number of people around the world who have taken and will take CQ and HCQ, it must necessarily consider the clinical and social impact of long term audiological side effects.

Drug-induced Sleep Endoscopy (DISE) with Simulation Bite to Predict the Success of Oral Appliance Therapy in Treating Obstructive Sleep Apnea/Hypopnea Syndrome (OSAHS)

Study objectives

Oral appliances have gained their place in the treatment of obstructive sleep apnea (OSA) where custom-made titratable mandibular advancement devices (MAD) have become the oral appliance of choice. This study aimed to asses the value of the drug-induced sleep endoscopy (DISE) using a MAD in the prediction of treatment outcome for OSAHS.

Methods

This is a prospective, single-center cohort study that enrolled sixty-six consecutive patients with diagnosed OSA (5 events/h < apnea-hypopnea index (AHI) < 50 events/h) to be treated with a custom-made titratable MAD. The patients were evaluated polysomnographically with the MAD in situ after the adaptation and titration period of 3 months. The associations between findings during DISE and treatment outcome were assessed.

Results

The subjects showed a wide range of severity of OSAHS pre-treatment: median AHI was 43.10 with a range from 20.13 to 66.07. The simulation bite was associated with a significant increase in cross-sectional area at level of the velopharynx, tongue base and epiglottis. MAD treatment response in the studied population was 91%, with a mean AHI improving from 43.10 to 12.93.

Conclusions

Drug-induced sleep endoscopy with simulation bite is an acceptably reproducible technique for determining the sites of obstruction in OSAHS subjects; it thus offers possibilities as a prognostic indicator for treatment with MAD.

Pharmacological, surgical and diagnostic innovations in Meniere's disease: a review

Meniere's disease is an inner ear disorder characterized by the presence of endolymphatic hydrops in the inner ear and symptomatology of recurrent and debilitating vertigo attacks, tinnitus, aural fullness, and fluctuating sensorineural hearing loss. Although many therapeutic options for MD have been proposed during years, no consensus has been reached by the scientific community. In the last decade, many therapeutic options have been proposed, as intratympanic steroid, intratympanic gentamicin, and intravenous glycerol. Recently, the role of the antisecretory factor in the diet of MD patients have been investigated. Surgery is recommended for intractable MD; some authors proposed new approaches including transcanal endoscopic infracochlear vestibular neurectomy, new marsupiliazation technique in sac surgery, and tenotomy of the stapedius and tensor tympani muscles.

Obstructive sleep apnoea/hypopnoea syndrome: relationship with obesity and management in obese patients

Obstructive sleep apnoea/hypopnoea syndrome (OSAHS) is a disease characterised by upper airway obstruction during sleep, quite frequent in the general population, even if underestimated. Snoring, sleep apnoea and diurnal hypersomnia are common in these patients. Central obesity plays a key role: it reduces the size and changes the conformation of the upper airways, besides preventing lung expansion, with consequent reduction of lung volumes. Furthermore, obese people are also resistant to leptin, which physiologically stimulates ventilation; as a result, this causes scarce awakening during apnoea. OSAHS diagnosis is based on the combination of clinical parameters, such as apnoea/hypopnoea index (AHI), medical history, physical examination and Mallampati score. The first objective reference method to identify OSAHS is polysomnography followed by sleep endoscopy. Therapy provides in the first instance reduction of body weight, followed by continuous positive airway pressure (CPAP), which still remains the treatment of choice in most patients, mandibular advancement devices (MAD) and finally otolaryngology or maxillofacial surgery. Among surgical techniques, central is barbed reposition pharyngoplasty (BRP), used in the field of multilevel surgery.

Biomarkers of laryngeal squamous cell carcinoma: a review

Laryngeal carcinoma is the second common malignancy of the upper aerodigestive tract after lung cancer; in most cases is a squamous cell carcinoma, whose risk factors include tobacco smoking and alcohol consumption. Despite therapeutic progress, the five-year overall survival rate for this malignancy has remained nearly 50% and many patients already present metastasis at the time of diagnosis. To date, there are no tools that predict the evolution of laryngeal carcinoma: in this light, during the last years, many studies were planned with the aim to investigate the role played by different biomarkers expressed by larynx cancer, which can help make an early diagnosis, predict disease evolution and direct therapeutic choice. This review aims to summarize these markers and correlating them with disease evolution.

Left mixed laryngocele in absence of risk factors: A case report and review of literature

Laryngocele is an uncommon benign cystic dilatation of the laryngeal saccule that communicates with the laryngeal lumen and contains air. On the basis of its localization, it can be traditionally classified in internal, external, or mixed. Usually unilateral and rarely bilateral, it may be congenital or acquired. It most often appears later in life without important symptoms except for cervical swelling. Here, together with a review of literature, we report the case of a 72-year-old man, smoker but without other specific risk factors, who presented laryngeal dyspnea for about one year. Neck CT scan performed during a previous hospitalization for respiratory failure revealed a left mixed laryngocele that was later surgically removed with cervicotomic access. The patient was discharged after one week. One month after surgery, we confirmed the absence of disease with video laryngoscopy.

•

Laryngocele is a rare benign cystic dilatation of laryngeal saccule.

•

Conditions increasing intraluminal laryngeal pressure are the main risk factors.

•

The diagnosis of laryngocele is essentially clinic, based on symptoms.

•

In some cases it can present with acute respiratory failure as pulmonary pathology.

•

Treatment is surgical excision, microlaryngoscopic, external or combined.

Pharmacological, Surgical and Diagnostic Innovations in Meniere's Disease: A Review

PURPOSE

To investigate literature about pharmacological, surgical, and diagnostic innovations for Meniere's Disease (MD).

SUMMARY

Meniere's disease is an inner ear disorder characterized by the presence of endolymphatic hydrops in the inner ear and symptomatology of recurrent and debilitating vertigo attacks, tinnitus, aural fullness, and fluctuating sensorineural hearing loss. Although many therapeutic options for MD have been proposed during years, no consensus has been reached by the scientific community. In the last decade, many therapeutic options have been proposed, as intratympanic steroid, intratympanic gentamicin, and intravenous glycerol. Recently, the role of the antisecretory factor in the diet of MD patients have been investigated. Surgery is recommended for intractable MD; some authors proposed new approaches including transcanal endoscopic infracochlear vestibular neurectomy, new marsupiliazation technique in sac surgery, and tenotomy of the stapedius and tensor tympani muscles.

Pleomorphic Adenoma of the Parotid Gland and Ipsilateral Thyroid Incidentaloma: Report of A Rare Case With Review of Literature

BACKGROUND

Pleomorphic adenomas are benign tumors of the salivary glands that mainly affect the lower pole of the superficial lobe of the parotid gland. The term "pleomorphic" refers to the epithelial and connective origin of the mass. The clinical presentation is typically that of asymptomatic swelling which increases in volume. Therapy consists in surgical removal of the tumor mass by parotidectomy with nerve preservation.

CASE DETAILS

This clinical case describes an interesting case of pleomorphic adenoma of the parotid gland in a 62-year-old patient. The patient presented with a long history of an asymptomatic mildly worsening swelling of the left parotid region. The peculiarity of the clinical case is the dimension of the adenoma (9x5x9 cm) and the presence of a thyroid incidentaloma (TI), consisting of a thyroid multinodular goiter composed of nodules, the largest of which measured 8 cm in diameter. This mass dislocated the laryngotracheal axis, compressed the larynx and caused the reduction of the respiratory space, making orotracheal intubation difficult and determining the need to perform a tracheotomy.

CONCLUSION

Benign pleomorphic adenomas can potentially reach large sizes if untreated. Socio-economic problems may be the reason for late diagnosis.

Dietary Restriction for The Treatment of Meniere's Disease

Meniere's disease (MD) is an idiopathic inner ear disorder characterized by spontaneous recurrent vertigo, fluctuating sensorineural hearing loss (SNHL), aural fullness and tinnitus. Endolymphatic hydrops (EH) of the inner ear is currently considered the pathophysiological mechanisms that underlies typical symptoms of MD. MD diagnosis is based on the criteria of the Baràny Society. There are many therapeutic options for MD, but none is considered effective by the scientific community. The first-line treatment commonly includes dietary modification, as low salt diet and reduction of alcohol and caffeine daily intake. Although some studies showed a positive effect of these dietary restrictions, even in the prevention of recurrences, currently there is no uniform consensus on their usefulness. New dietary approach, such SPC-flakes, are being evaluated: further assessments will be needed to validate their use in clinical practice.

Inner-Ear Disorders Presenting with Air-Bone Gaps: A Review

Air-bone gaps (ABGs) are commonly found in patients with conductive or mixed hearing loss generally due to outer- and/or middle-ear diseases such as otitis externa, tympanic membrane perforation, interruption or fixation of the ossicular chain, and chronic suppurative otitis media. ABGs can also be found in correlation with inner-ear disorders, such as endolymphatic hydrops, enlarged vestibular aqueduct syndrome, semicircular canal dehiscence, gusher syndrome, cochlear dehiscence, and Paget disease's as well cerebral vascular anomalies including dural arteriovenous fistula. The typical clinical presentation of inner-ear conditions or cerebral vascular anomalies causing ABGs includes audiological and vestibular symptoms like vertigo, oscillopsia, dizziness, imbalance, spinning sensation, pulsatile or continuous tinnitus, hyperacusis, autophony, auricular fullness, Tullio's phenomenon, and Hennebert's sign. Establishing a definitive diagnosis of the underlying condition in patients presenting with an ABG is often challenging to do and, in many patients, the condition may remain undefined. Results from an accurate clinical, audiological, and vestibular evaluation can be suggestive for the underlying condition; however, radiological assessment by computed tomography and/or magnetic resonance imaging is mandatory to confirm any diagnostic suspicion. In this review, we describe and discuss the most recent updates available regarding the clinical presentation and diagnostic workup of inner-ear conditions that may present together with ABGs.

Rehabilitation Protocol for Unilateral Laryngeal and Lingual Paralysis (Tapia Syndrome): Comment About "A Challenging Case of Tapia Syndrome After Total Thyroidectomy" By Ildem Deveci, Mehmet Surmeli, and Reyhan Surmeli

Tapia syndrome is a rare complication after surgery, with ipsilateral paralysis of vocal cord and tongue due to extracranial involvement of recurrent laryngeal and hypoglossal nerves. Tapia's case report is extremely interesting for both the rarity of the reported cases and for the importance of an early rehabilitation. In a previous work, we reported a case of Tapia syndrome after cardiac surgery for aortic aneurysm, and the protocol of logopedic rehabilitation adopted. In the postoperative period, he developed severe dyspnea and dysphagia that required a tracheostomy and a logopedic rehabilitation therapy that led to a fast and efficient swallowing without aspiration after 47 sessions (less than 4 months). The progressive recovery of the function suggests aprassic nerve damage. However, the logopedic therapy is recommended to limit the possibility of permanent functional deficits and quickly recover swallowing and phonation.

Ranking the invasions of cheaters in structured populations

The identification of the most influential individuals in structured populations is an important research question, with many applications across the social and natural sciences. Here, we study this problem in evolutionary populations on static networks, where invading cheaters can lead to the collapse of cooperation. We propose six strategies to rank the invading cheaters and identify those which mostly facilitate the collapse of cooperation. We demonstrate that the type of successful rankings depend on the selection strength, the underlying game, and the network structure. We show that random ranking has generally little ability to successfully identify invading cheaters, especially for the stag-hunt game in scale-free networks and when the selection strength is strong. The ranking based on degree can successfully identify the most influential invaders when the selection strength is weak, while more structured rankings perform better at strong selection. Scale-free networks and strong selection are generally detrimental to the performance of the random ranking, but they are beneficial for the performance of structured rankings. Our research reveals how to identify the most influential invaders using statistical measures in structured communities, and it demonstrates how their success depends on population structure, selection strength, and on the underlying game dynamics.

SCORE risk scale as a prognostic factor after sudden sensorineural hearing loss

Menezes et al. recently published an interesting study on cardiovascular prognostic factors for sudden sensorineural hearing loss (SSNHL), analyzing therapeutic strategies with intravenous and intratympanic corticosteroids and evaluating the application of the Systematic Coronary Risk Evaluation risk scale to classify risk in patients with SSNHL. In addition to intravenous and intratympanic corticosteroids, we would like to stress the role of hyperbaric oxygen therapy (HBOT). The new guidelines on SSNHL and the most recent scientific evidence emphasize the therapeutic role of HBOT. In a previous study, we recommended the use of HBOT in addition to intravenous steroid for patients with idiopathic SSNHL. For the best outcomes, we also recommended starting treatment within 14 days from the onset of SSNHL. In the same article, we discussed potential risk factors for SSNHL. Among cardiovascular risk factors, we suggest the possible association between patent foramen ovale (PFO) and SSNHL. The higher prevalence of PFO in our patients (50%) compared to controls suggests that SSNHL may be attributable to a paradoxical embolism, such as a venous embolism as a result of PFO.

A Genetic Circuit Compiler: Generating Combinatorial Genetic Circuits with Web Semantics and Inference

A central strategy of synthetic biology is to understand the basic processes of living creatures through engineering organisms using the same building blocks. Biological machines described in terms of parts can be studied by computer simulation in any of several languages or robotically assembled in vitro. In this paper we present a language, the Genetic Circuit Description Language (GCDL) and a compiler, the Genetic Circuit Compiler (GCC). This language describes genetic circuits at a level of granularity appropriate both for automated assembly in the laboratory and deriving simulation code. The GCDL follows Semantic Web practice, and the compiler makes novel use of the logical inference facilities that are therefore available. We present the GCDL and compiler structure as a study of a tool for generating κ-language simulations from semantic descriptions of genetic circuits.

Cholesteatoma vs granulation tissue: a differential diagnosis by DWI-MRI apparent diffusion coefficient

PURPOSE

To diagnose cholesteatoma when it is not visible through tympanic perforation, imaging techniques are necessary. Recently, the combination of computed tomography and magnetic resonance imaging has proven effective to diagnose middle ear cholesteatoma. In particular, diffusion weighted images have integrated the conventional imaging for the qualitative assessment of cholesteatoma. Accordingly, the aim of this study was to obtain a quantitative analysis of cholesteatoma calculating the apparent diffusion coefficient value. So, we investigated whether it could differentiate cholesteatoma from other inflammatory tissues both in a preoperative and in a postoperative study.

METHODS

This study included 109 patients with clinical suspicion of primary or residual/recurrent cholesteatoma. All patients underwent preoperative computed tomography and magnetic resonance imaging with diffusion sequences before primary or second-look surgery to calculate the apparent diffusion coefficient value.

RESULTS

We found that the apparent diffusion coefficient values of cholesteatoma were significantly lower than those of non cholesteatoma. In particular, the apparent diffusion coefficient median value of the cholesteatoma group (0.84 × 10^- 3 mm²/s) differed from the inflammatory granulation tissue (2.21 × 10^- 3 mm²/s) group (p < 2.2 × 10^- 16). Furthermore, we modeled the probability of cholesteatoma by means of a logistic regression and we determined an optimal cut-off probability value of ~ 0.86 (specificity = 1.0, sensitivity = 0.97), corresponding to an apparent diffusion coefficient cut-off value of 1.37 × 10^- 3 mm²/s.

CONCLUSIONS

Our study has demonstrated that apparent diffusion coefficient values constitute a valuable quantitative parameter for preoperative differentiation of cholesteatomas from other middle ear inflammatory diseases and for postoperative diagnosis of recurrent/residual cholesteatomas.

Cooperation in microbial communities and their biotechnological applications

Microbial communities are increasingly utilized in biotechnology. Efficiency and productivity in many of these applications depends on the presence of cooperative interactions between members of the community. Two key processes underlying these interactions are the production of public goods and metabolic cross-feeding, which can be understood in the general framework of ecological and evolutionary (eco-evo) dynamics. In this review, we illustrate the relevance of cooperative interactions in microbial biotechnological processes, discuss their mechanistic origins and analyse their evolutionary resilience. Cooperative behaviours can be damaged by the emergence of 'cheating' cells that benefit from the cooperative interactions but do not contribute to them. Despite this, cooperative interactions can be stabilized by spatial segregation, by the presence of feedbacks between the evolutionary dynamics and the ecology of the community, by the role of regulatory systems coupled to the environmental conditions and by the action of horizontal gene transfer. Cooperative interactions enrich microbial communities with a higher degree of robustness against environmental stress and can facilitate the evolution of more complex traits. Therefore, the evolutionary resilience of microbial communities and their ability to constraint detrimental mutants should be considered to design robust biotechnological applications.

Endoscopic tympanoplasty in the treatment of chronic otitis media: our experience

CONCLUSION

The endoscopy ensures good surgical exposure of hidden areas, frequently sites of residual cholesteatoma. Also, the minimally invasive endoscopic approach is more respectful of anatomy and functionality of the middle ear, restoring and preserving mastoid mucosa, with faster healing time.

OBJECTIVES

To investigate the benefits that the systematic use of endoscopy in middle ear surgery has made.

STUDY DESIGN

Retrospective cohort studies.

METHOD

Two groups of patients were surgically treated for inflammatory diseases of the middle ear. The first group refers to the Pre-Endoscopic period, the second one to the Endoscopic Period. This study analyzed the type of surgical approach (Transcanalar vs Retroauricolar) in all cases treated and the differences in incidence of residual disease in the cases treated for cholesteatoma.

RESULTS

The oto-endoscopy led to a significant increase (p < .01) of the transcanalar approach and to a significant reduction (p < .05) of residual cholesteatoma at the second look surgery.

Detecting the Collapse of Cooperation in Evolving Networks

The sustainability of biological, social, economic and ecological communities is often determined by the outcome of social conflicts between cooperative and selfish individuals (cheaters). Cheaters avoid the cost of contributing to the community and can occasionally spread in the population leading to the complete collapse of cooperation. Although such collapse often unfolds unexpectedly, it is unclear whether one can detect the risk of cheater’s invasions and loss of cooperation in an evolving community. Here, we combine dynamical networks and evolutionary game theory to study the abrupt loss of cooperation with tools for studying critical transitions. We estimate the risk of cooperation collapse following the introduction of a single cheater under gradually changing conditions. We observe an increase in the average time it takes for cheaters to be eliminated from the community as the risk of collapse increases. We argue that such slow system response resembles slowing down in recovery rates prior to a critical transition. In addition, we show how changes in community structure reflect the risk of cooperation collapse. We find that these changes strongly depend on the mechanism that governs how cheaters evolve in the community. Our results highlight novel directions for detecting abrupt transitions in evolving networks.

Annotation of rule-based models with formal semantics to enable creation, analysis, reuse and visualization

MOTIVATION

Biological systems are complex and challenging to model and therefore model reuse is highly desirable. To promote model reuse, models should include both information about the specifics of simulations and the underlying biology in the form of metadata. The availability of computationally tractable metadata is especially important for the effective automated interpretation and processing of models. Metadata are typically represented as machine-readable annotations which enhance programmatic access to information about models. Rule-based languages have emerged as a modelling framework to represent the complexity of biological systems. Annotation approaches have been widely used for reaction-based formalisms such as SBML. However, rule-based languages still lack a rich annotation framework to add semantic information, such as machine-readable descriptions, to the components of a model.

RESULTS

We present an annotation framework and guidelines for annotating rule-based models, encoded in the commonly used Kappa and BioNetGen languages. We adapt widely adopted annotation approaches to rule-based models. We initially propose a syntax to store machine-readable annotations and describe a mapping between rule-based modelling entities, such as agents and rules, and their annotations. We then describe an ontology to both annotate these models and capture the information contained therein, and demonstrate annotating these models using examples. Finally, we present a proof of concept tool for extracting annotations from a model that can be queried and analyzed in a uniform way. The uniform representation of the annotations can be used to facilitate the creation, analysis, reuse and visualization of rule-based models. Although examples are given, using specific implementations the proposed techniques can be applied to rule-based models in general.

AVAILABILITY AND IMPLEMENTATION

The annotation ontology for rule-based models can be found at http://purl.org/rbm/rbmo The krdf tool and associated executable examples are available at http://purl.org/rbm/rbmo/krdf

CONTACT

anil.wipat@newcastle.ac.uk or vdanos@inf.ed.ac.uk.

Hyperbaric oxygen for idiopathic sudden hearing loss: is the routine application helpful?

CONCLUSION

We recommend the routine application of hyperbaric oxygen (HBO) in conjunction with intravenous steroid (IVS) for all patients with idiopathic sudden sensorineural hearing loss (ISSNHL). For best results, this therapy must be started within 14 days.

OBJECTIVE

To investigate the necessity of routine application of HBO therapy for ISSNHL.

METHODS

This was a retrospective cohort study. A total of 300 patients (300 diseased ears) were divided into 3 groups according to the therapy received: IVS (group A), HBO (group B), or IVS + HBO (group C). Patients in each treatment group were subdivided into subgroups according to the time of therapy initiation. The outcomes of their hearing recovery were classified into three recovery grades: good, fair, and poor.

RESULTS

The proportion of patients responding to therapy and those with complete recovery was the highest in the combined treatment group, 84% and 58%, respectively, regardless of the initial hearing levels. In all the groups, mean gains of cases in whom therapy was started in the first 2 weeks were significantly higher (p < 0.05) and hypercholesterolemia (>240 mg/dl) caused significantly worse responses (p < 0.05).

Recurrent epistaxis following stabbing headache responsive to acetazolamide

The co-occurrence of epistaxis and headache is not uncommon in migraine patients, although only few case reports have been published. A trigeminovascular activation may be causally involved although the exact mechanisms linking epistaxis and migraine remain unclear. Significant dural sinus stenosis may sustain or worsen an increased cerebral venous pressure and is considered a radiological predictor of idiopathic intracranial hypertension. We report a 49-year-old female patient with chronic migraine associated to stabbing headache-like attacks followed by epistaxis and by the resolution or the significant improvement of pain. As she also reported adjunctive symptoms suggestive of raised intracranial pressure and showed a bilateral narrowing of transverse sinuses at MR-venography, a possible intracranial hypertension was hypothesized despite the lack of papilledema. Acetazolamide 250 mg twice/day was added to therapy and the patient reported sudden reduction of headache severity and frequency and complete resolution of both the stabbing pain and the recurrent epistaxis, maintained for 5 months. At treatment discontinuation she complained the worsening of migraine headache and the reoccurrence of the superimposed stabbing pain followed by epistaxis. The mechanism linking the sequential occurrence of painful stabs, epistaxis and relief from pain with raised intracranial pressure in our patients remains unclear. We speculate that the sudden reopening of collapsed collateral veins of the anterior venous circle, possibly prompted by periodic waves of central venous hypertension coupled with intracranial hypertensive peaks, could explain the unusual strict time succession of painful stabs, epistaxis, and subsequent resolution of pain.

Hyaluronan in the Treatment of Chronic Rhinosinusitis with Nasal Polyposis

Chronic rhinosinusitis (CRS) is a common condition and affects the quality of life of approximately 16 % of adults in US and 10.9 % in Europe. Hyaluronan (HA) is a nonsulphate glycosaminoglycan found in the extracellular matrix of connective tissues, and plays an important role in the healing process and repair of mucosal surfaces. We aim to evaluate the effect of HA on nasal symptoms and endoscopic appearance in patients with CRS and nasal polyps (NP) who have not undergone sinus surgery. Eighty patients older than 18 years old were randomized to receive either open-label nebulized saline solution (NS) or intranasal corticosteroid spray (ICS) 200 µg bid or nebulized sodium hyaluronate (NHA, YABRO(®)) or both ICS and NHA. Results were collected at 1 month, 3 months and 3 months after treatment. Significant improvements in nasal symptoms scores, endoscopic appearance scores, radiologic scores, rhinomanometry and saccharine clearance test were observed in the NHA, ICS and ICS + NHA groups after 1 month and 3 months of treatment compared with baseline (all p ≤ 0.005). The use of oral steroids was significantly reduced after 3 months of therapy in the same groups versus baseline (all p < 0.05). The incidence of adverse events at 3 months was similar between the 4 groups (all p > 0.05). Throat irritation, nasal burning and drug-related epistaxis were not reported in the group NHA. HA, as a nebulized nasal douche preparation, improved nasal symptoms and endoscopic appearances in patients with CRS and NP who have not undergone sinus surgery.

Tragal cartilage shield tympanoplasty: our technique and results in 612 cases

CONCLUSION

This study reveals that tragal cartilage tympanoplasty is a reliable technique, it has a high degree of graft take, and the tympanic re-aeration and hearing results are satisfactory.

OBJECTIVE

Cartilage is the grafting material of choice in advanced pathologies of the middle ear while the indications for its routine use remain controversial. The purpose of this study was to report our long-term experience with the 'tragal cartilage shield' tympanoplasty.

METHODS

This was a retrospective case series. The study was conducted on 612 adult patients from January 2003 until January 2012. We evaluated graft take, pure-tone average air-bone gap (PTA-ABG), postoperative aeration, and complications. The mean postoperative follow-up was 68 months.

RESULTS

Sex, age, and tobacco smoke did not have any impact on postoperative results. Graft take was achieved in 99.35% of patients; there were no immediate postoperative complications. The overall average preoperative PTA-ABG was 44.95 ± 7.77 dB, whereas 1 year after surgery it was 10.66 ± 5.41 dB (p < 0.0001). Statistically significant improvement was observed up to 10 years after surgery. Moreover, we obtained a good tympanic ventilation (1 year after surgery, the average aeration score was 9.09 ± 1.93), which was stable up to 10 years.

Cooperation and competition in the dynamics of tissue architecture during homeostasis and tumorigenesis

The construction of a network of cell-to-cell contacts makes it possible to characterize the patterns and spatial organization of tissues. Such networks are highly dynamic, depending on the changes of the tissue architecture caused by cell division, death and migration. Local competitive and cooperative cell-to-cell interactions influence the choices cells make. We review the literature on quantitative data of epithelial tissue topology and present a dynamical network model that can be used to explore the evolutionary dynamics of a two dimensional tissue architecture with arbitrary cell-to-cell interactions. In particular, we show that various forms of experimentally observed types of interactions can be modelled using game theory. We discuss a model of cooperative and non-cooperative cell-to-cell communication that can capture the interplay between cellular competition and tissue dynamics. We conclude with an outlook on the possible uses of this approach in modelling tumorigenesis and tissue homeostasis.

Plasticity facilitates sustainable growth in the commons

In the commons, communities whose growth depends on public good, individuals often rely on surprisingly simple strategies, or heuristics, to decide whether to contribute to the shared resource (at risk of exploitation by free-riders). Although this appears a limitation, we show here how four heuristics lead to sustainable growth when coupled to specific ecological constraints. The two simplest ones—contribute permanently or switch stochastically between contributing or not—are first shown to bring sustainability when the public good efficiently promotes growth. If efficiency declines and the commons is structured in small groups, the most effective strategy resides in contributing only when a majority of individuals are also contributors. In contrast, when group size becomes large, the most effective behaviour follows a minimal-effort rule: contribute only when it is strictly necessary. Both plastic strategies are observed in natural scenarios across scales that present them as relevant social motifs for the sustainable management of public goods.

Prosperity is associated with instability in dynamical networks

Social, biological and economic networks grow and decline with occasional fragmentation and re-formation, often explained in terms of external perturbations. We show that these phenomena can be a direct consequence of simple imitation and internal conflicts between 'cooperators' and 'defectors'. We employ a game-theoretic model of dynamic network formation where successful individuals are more likely to be imitated by newcomers who adopt their strategies and copy their social network. We find that, despite using the same mechanism, cooperators promote well-connected highly prosperous networks and defectors cause the network to fragment and lose its prosperity; defectors are unable to maintain the highly connected networks they invade. Once the network is fragmented it can be reconstructed by a new invasion of cooperators, leading to the cycle of formation and fragmentation seen, for example, in bacterial communities and socio-economic networks. In this endless struggle between cooperators and defectors we observe that cooperation leads to prosperity, but prosperity is associated with instability. Cooperation is prosperous when the network has frequent formation and fragmentation.

Notes on the microbiology of cholesteatoma: clinical findings and treatment

Anomalous proliferation of the cholesteatoma epithelium is caused by extrinsic factors such as toxins or bacterial antigens combined with lytic enzymes, lymphokines and cytokines released from the inflammatory infiltrate. This could explain the close relationship between the aggressiveness of cholesteatoma and repeated bacterial superinfection, therefore it is very important to know the bacteria involved in order to control the regrowth of skin following surgery, reduce the aggressive potential of the cholesteatoma and limit the incidence of complications. This study focused on 70 females and 80 males aged between 15 and 65 years, affected by cholesteatomatous otitis media; all underwent bacteriological examination of the auricular secretion. The floral bacteria which proved to play the most important role (60.3%) were the aerobic type and the highest levels were those of Pseudomonas aeruginosa (31.1%) followed by Staphylococcus aureus (19.1%), Proteus mirabilis (7.7%), Escherichia coli (1.4%) and Klebsiella pneumoniae (1%). Anaerobic floral bacteria were found in a fairly high percentage of cases (38.2%); in particular, anaerobic gram-positive cocci (Peptococcus 12.4% and Peptostreptococcus in 4.8% of cases), Bacteroides (12.4%), Clostridium (3.8%), Fusobacterium (2.9%) and Propionobacterium (1.9%) were isolated. In 3 cases of mycetes (1.4%) only Aspergillus, in association with Pseudomonas and Staphylococcus, was identified. The study showed, then, how effective second generation fluoroquinolones and third generation cephalosporins are (the latter being used in pre-adolescent children), the reason being that these antibiotics work not only on Pseudomonas and Staphylococcus, but also on the anaerobic bacteria.

Tragal cartilage in tympanoplasty: anatomic and functional results in 306 cases

Cartilage is the grafting material of choice in advanced disorders of the middle ear while the indications for its routine use remain controversial due to the possible detrimental effect on post-operative hearing. Aim of the present study was to report personal experience with "tragal cartilage shield" tympanoplasty. The study focused on 306 adult patients (236 primary procedures and 70 revisions from January 2003 to June 2007). Mean post-operative follow-up was 37 months (range 1-66). The following parameters were evaluated: graft take, change between the pre- and post-operative pure-tone average air-bone gap (PTA-ABG), post-operative complications. Graft take was achieved in 304 patients (99.35%) and there were no immediate post-operative complications. The overall average pre-operative pure-tone average air-bone gap was 43.79 +/- 7.07 dB, whereas the post-operative (1 year after surgery) pure-tone average air-bone gap was 10.43 +/- 5.25 dB (p < 0.0001). Statistically significant improvement was observed up to 5 years after surgery. This study reveals that tragal cartilage shield tympanoplasty is a reliable technique, in fact it has a high degree of graft take and hearing results are satisfactory. Furthermore, the cartilage is a satisfactory grafting material because it is easily accessible, easy to adapt, resistant to negative middle ear pressures, stable, elastic, well tolerated by the middle ear, resistant to resorption. Therefore, we also recommend its use in less severe middle ear disorders, in which the functional outcome is more essential.

Osteosarcoma of the larynx: a case report

BACKGROUND

We add a new rare illustrative case of osteosarcoma of the larynx to the literature.

CASE PRESENTATION

The patient (man; 56 years old) first underwent several biopsies, followed in the end by a total laryngectomy. Diagnosis was histological. The patient developed regional and distant metastases and died of disease after 3 months from surgery.

CONCLUSION

Osteosarcoma of the larynx is a rare and aggressive tumour with a poor long-term prognosis. The preferred treatment for this tumour is aggressive surgery.To perform a diagnosis we must be in presence of osteoid or of neoplastic osseous tissue directly produced by the neoplastic cells.

Monopolar and bipolar radiofrequency thermal ablation of inferior turbinates: 20-month follow-up

OBJECTIVE

We prospectively evaluated the efficacy and morbidity of monopolar and bipolar radiofrequency volumetric tissue reduction (RFVTR) of inferior turbinates during a 20-month follow-up.

METHODS

The study was conducted on 150 patients randomly assigned into two groups of 75 each. In group A, we used the bipolar device "Coblator II ENT" (Arthrocare Corp, Sunnyvale, CA) and in group B the monopolar device Somnoplasty (Somnus Medical Technologies, Inc, Sunnyvale, CA). Nasal endoscopy, visual analog scale, anterior active rhinomanometry, acoustic rhinometry, and saccharin tests were used to assess the outcomes of the treatments.

RESULTS

Turbinate edema and nasal obstruction decreased significantly (P < 0.0001) in group A seven days after surgery and in group B from month 1. The nasal symptoms were significantly reduced in both groups from the first month (P < 0.0001). A significant increase (P < 0.0001) in nasal volume and decrease in nasal resistance were detected in the first month. No difference was found from three to 20 months after surgery (P > 0.5).

CONCLUSION

We have shown that both methods of RFVTR can produce a long-term improvement on symptoms and on maintenance of nasal function.

Oncocytic cyst of the larynx: an unusual occurrence

Oncocytic cysts of the larynx are rare benign, slow growing lesions that are lined predominantly or exclusively by oncocytes, the cytoplasm of which contains a considerable number of hypertrophied mitochondria, which accounts for their eosinophilia and swollen appearance. The oncocytic change is a phenomenon of metaplasia which occurs frequently in epithelial endocrine cells with high metabolic activity and it is also associated with inflammation, degenerative process or cellular ageing. In the larynx, oncocytic metaplasia is very uncommon, but it is occasionally seen in the lining of laryngeal cysts, which are found most commonly in the ventricles or in the false vocal cords, where seromucinous glands are more abundant. Oncocytic cysts typically occur in the elderly and are usually solitary, with involvement of an isolated site, whereas diffuse involvement with multiple cysts is extremely rare. Hoarseness is the most common presenting symptom, while pain, stridor or laryngeal obstruction are unusual complaints. Management of these lesions is conservative and consists of local excision, endoscopic removal being the treatment of choice. Although oncocytic cysts are benign lesions, follow-up is recommended, as recurrence is possible, especially in the case of patients with multiple involvement, since they may show a tendency to develop new cysts. To date, approximately 150 cases of laryngeal oncocytic cysts have been published. Herein, a very unusual case is presented occurring in a 43-year-old male patient, therefore, "epidemiologically" atypical for developing oncocytic lesions. Causes of oncocytic changes and pathogenesis of laryngeal cysts are discussed.

Otorhinolaryngology-related tuberculosis

Data from personal case histories, from 1984 to 2000 inclusive, are reported in order to contribute to a better understanding of some of the clinical and epidemiological ENT associated TB aspects. Analysis of these data shows that: (1) Like the pulmonary form, ENT localizations are increasing due to the traditional risk factors (immigration, poverty, immunodeficiency, drug addiction). (2) They are generally clinically primitive forms (which are found in extrapulmonary regions as the first expression of tubercular disease) and typically affect young people with a slight prevalence among females. Lymph gland localizations are the most frequent.