Subduction-driven recycling of continental margin lithosphere.

Whereas subduction recycling of oceanic lithosphere is one of the central themes of plate tectonics, the recycling of continental lithosphere appears to be far more complicated and less well understood. Delamination and convective downwelling are two widely recognized processes invoked to explain the removal of lithospheric mantle under or adjacent to orogenic belts. Here we relate oceanic plate subduction to removal of adjacent continental lithosphere in certain plate tectonic settings. We have developed teleseismic body wave images from dense broadband seismic experiments that show higher than expected volumes of anomalously fast mantle associated with the subducted Atlantic slab under northeastern South America and the Alboran slab beneath the Gibraltar arc region; the anomalies are under, and are aligned with, the continental margins at depths greater than 200 kilometres. Rayleigh wave analysis finds that the lithospheric mantle under the continental margins is significantly thinner than expected, and that thin lithosphere extends from the orogens adjacent to the subduction zones inland to the edges of nearby cratonic cores. Taking these data together, here we describe a process that can lead to the loss of continental lithosphere adjacent to a subduction zone. Subducting oceanic plates can viscously entrain and remove the bottom of the continental thermal boundary layer lithosphere from adjacent continental margins. This drives surface tectonics and pre-conditions the margins for further deformation by creating topography along the lithosphere-asthenosphere boundary. This can lead to development of secondary downwellings under the continental interior, probably under both South America and the Gibraltar arc, and to delamination of the entire lithospheric mantle, as around the Gibraltar arc. This process reconciles numerous, sometimes mutually exclusive, geodynamic models proposed to explain the complex oceanic-continental tectonics of these subduction zones.

Choline kinase inhibition in rheumatoid arthritis.

OBJECTIVES: Little is known about targeting the metabolome in non-cancer conditions. Choline kinase (ChoKα), an essential enzyme for phosphatidylcholine biosynthesis, is required for cell proliferation and has been implicated in cancer invasiveness. Aggressive behaviour of fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA) led us to evaluate whether this metabolic pathway could play a role in RA FLS function and joint damage. METHODS: Choline metabolic profile of FLS cells was determined by (1)H magnetic resonance spectroscopy ((1)HMRS) under conditions of ChoKα inhibition. FLS function was evaluated using the ChoKα inhibitor MN58b (IC50=4.2 µM). For arthritis experiments, mice were injected with K/BxN sera. MN58b (3 mg/kg) was injected daily intraperitoneal beginning on day 0 or day 4 after serum administration. RESULTS: The enzyme is expressed in synovial tissue and in cultured RA FLS. Tumour necrosis factor (TNF) and platelet-derived growth factor (PDGF) stimulation increased ChoKα expression and levels of phosphocholine in FLS measured by Western Blot (WB) and metabolomic studies of choline-containing compounds in cultured RA FLS extracts respectively, suggesting activation of this pathway in RA synovial environment. A ChoKα inhibitor also suppressed the behaviour of cultured FLS, including cell migration and resistance to apoptosis, which might contribute to cartilage destruction in RA. In a passive K/BxN arthritis model, pharmacologic ChoKα inhibition significantly decreased arthritis in pretreatment protocols as well as in established disease. CONCLUSIONS: These data suggest that ChoKα inhibition could be an effective strategy in inflammatory arthritis. It also suggests that targeting the metabolome can be a new treatment strategy in non-cancer conditions.

Identification of natural and anthropogenic signals in controlled source seismic experiments.

The analysis of the background noise in seismic networks has proved to be a powerful tool not only to acquire new insights on the crustal structure, but also to monitor different natural and anthropogenic processes. We show that data acquired during controlled source experiments can also be a valuable tool to monitor such processes, in particular when using high-density deployments. Data from a wide-angle reflection and refraction seismic profile in the central-northwest part of Iberia is used to identify signals related to aircrafts, road traffic, quarry blasts, wind blow, rainfall or thunders. The most prominent observations are those generated by a helicopter and an airplane flying following trajectories subparallel to the profile, which are tracked along 200 km with a spatial resolution of 350 m, hence providing an exceptional dataset. Other highlights are the observation of the Doppler effect on signals generated by moving cars and the high-density recording of acoustic waves generated by thunders. In addition to the intrinsic interest of identifying such signals, this contribution proves that it is worth inspecting the data acquired during seismic experiments beyond the time interval including the arrival of the seismic waves generated by the controlled source.

[Biomechanics of the bone-screw interface in transpedicular spinal instrumentation]. / Biomecánica de la interfaz hueso-tornillo en instrumentación transpedicular de columna.

Implant loosening, catastrophic failure of the bone-screw interface, material migration, and loss of stability of the fixation component assembly constitute a serious complication in adult spinal surgery. The contribution of biomechanics is based on experimental measurement and simulation of transpedicular spinal fixations. The cortical insertion trajectory showed an increase in the resistance of the screw-bone interface with respect to the pedicle insertion trajectory, both for axial traction forces to the screw and for stress distribution in the vertebra. The double-threaded screws and standard pedicle screws had similar strength. Partially threaded screws with four-thread showed better resistance to fatigue in terms of a higher failure load and number of cycles to fail. Cement or hydroxyapatite augmented screws with also showed a better fatigue resistance in osteoporotic vertebrae. Rigid segment simulations confirmed the presence of higher stresses on the intervertebral discs causing damage to adjacent segments. The posterior body of the vertebra may be subjected to high stresses, in the bone-screw interface, being this bone region more susceptible to failure.

El aflojamiento de los implantes, la falla catastrófica de la interfaz hueso-tornillo, la migración de material y la pérdida de estabilidad de los componentes del ensamble de la fijación constituyen una seria complicación en la cirugía de columna de adultos. La contribución de la biomecánica se basa en la medición experimental y la simulación de las fijaciones transpediculares de columna. La trayectoria de inserción cortical mostró un incremento en la resistencia de la interfase tornillo-hueso respecto a la inserción pedicular tanto para fuerzas de tracción axiales al tornillo como en distribución de esfuerzos en la vértebra. Los tornillos de doble rosca tuvieron una resistencia similar a los pediculares estándar. Los tornillos de rosca parcial de cuatro filetes mostraron mejor resistencia a la fatiga en cuanto a mayor carga de rotura y número de ciclos para la falla. Los tornillos aumentados, ya sea con cemento o hidroxiapatita mejoraron también la resistencia a la fatiga en vértebras osteoporóticas. Las simulaciones de segmentos rígidos confirmaron la presencia de esfuerzos superiores en los discos intervertebrales que provocan el daño de los segmentos adyacentes. La parte posterior de las vértebras puede estar sometida a mayores esfuerzos, fundamentalmente en la superficie de la interfaz hueso-tornillo, por lo que son más susceptibles a la falla en esta región.

[Systematic review of the prognostic utility of D-dimer, disseminated intravascular coagulation, and anticoagulant therapy in COVID-19 critically ill patients]. / Revisión sistemática sobre la utilidad pronóstica del dímero-D, coagulación intravascular diseminada y tratamiento anticoagulante en pacientes graves con COVID-19.

During the new pandemic caused by SARS-CoV-2, there is short knowledge regarding the management of different disease areas, such as coagulopathy and interpretation of D-dimer levels, its association with disseminated intravascular coagulation (DIC) and controversy about the benefit of anticoagulation. Thus, a systematic review has been performed to define the role of D-dimer in the disease, the prevalence of DIC and the usefulness of anticoagulant treatment in these patients. A literature search was performed to analyze the studies of COVID-19 patients. Four recommendations were drawn based on expert opinion and scientific knowledge, according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. The present review suggests the presence of higher levels of D-dimer in those with worse prognosis, there may be an overdiagnosis of DIC in the course of the disease and there is no evidence on the benefit of starting anticoagulant treatment based only on isolated laboratory data.

[Placement of a bronchial blocker through the I-gel supraglottic airway device for single-lung ventilation: preliminary study]. / Ventilación unipulmonar con bloqueador bronquial a través del dispositivo supraglótico I-gel. Estudio preliminar.

To describe the use of the I-gel supraglottic airway device when placing a bronchial blocker for single-lung ventilation, as applied in a preliminary study to explore the feasibility of adopting the technique with appropriate, selected patients undergoing certain thoracic surgery procedures. We used the technique for single-lung ventilation in 25 patients who required isolation of a lung for a variety of thoracic surgical procedures. A bronchial blocker was placed under direct visualization through a fiberoptic bronchoscope and the I-gel supraglottic device. The I-gel mask allowed us to establish a reliable, safe seal of the airway. For an anesthetist with sufficient experience in managing a flexible fiberoptic bronchoscope, it was possible to carry out all procedures without remarkable anesthetic or surgical events. Single-lung ventilation achieved by introducing a bronchial blocker through the I-gel supraglottic device can facilitate safe, effective management of selected patients who must undergo certain thoracic surgery procedures.

Severe infection due to the SARS-CoV-2 coronavirus: Experience of a tertiary hospital with COVID-19 patients during the 2020 pandemic. / Infección grave por coronavirus SARS-CoV-2: experiencia en un hospital de tercer nivel con pacientes afectados por COVID-19 durante la pandemia 2020.

OBJECTIVE: To describe the clinical and respiratory characteristics of a cohort of 43 patients with COVID-19 after an evolutive period of 28 days. DESIGN: A prospective, single-center observational study was carried out. SETTING: Intensive care. PATIENTS: Patients admitted due to COVID-19 and respiratory failure. INTERVENTIONS: None. VARIABLES: Automatic recording was made of demographic variables, severity parameters, laboratory data, assisted ventilation (HFO: high-flow oxygen therapy and IMV: invasive mechanical ventilation), oxygenation (PaO2, PaO2/FiO2) and complications. The patients were divided into three groups: survivors (G1), deceased (G2) and patients remaining under admission (G3). The chi-squared test or Fisher exact test (categorical variables) was used, along with the Mann-Whitney U-test or Wilcoxon test for analyzing the differences between medians. Statistical significance was considered for p<0.05. RESULTS: A total of 43 patients were included (G1=28 [65.1%]; G2=10 [23.3%] and G3=5 [11.6%]), with a mean age of 65 years (range: 52-72), 62% males, APACHE II 18 (15-24), SOFA 6 (4-7). Arterial hypertension (30.2%) and obesity (25.6%) were the most frequent comorbidities. High-flow oxygen therapy was used in 62.7% of the patients, with failure in 85%. In turn, 95% of the patients required IMV and 85% received ventilation in prone decubitus. In the general population, initial PaO2/FiO2 improved after 7 days (165 [125-210] vs.194 [153-285]; p=0.02), in the same way as in G1 (164 [125-197] vs. 207 [160-294]; p=0.07), but not in G2 (163 [95-197] vs. 135 [85-177]). No bacterial coinfection was observed. The incidence of IMV-associated pneumonia was high (13 episodes/1000 days of IMV). CONCLUSIONS: Patients with COVID-19 require early IMV, a high frequency of ventilation in prone decubitus, and have a high incidence of failed HFO. The lack of improvement of PaO2/FiO2 at 7 days could be a prognostic marker. .

Detection of human papillomavirus in cervical swab samples by ViraPap and in cervical biopsy specimens by in situ hybridization.

Human papillomavirus (HPV) detection in cervical swab specimens by ViraPap and in cervical biopsies by the ViraType in situ hybridization assay was correlated with concurrent cytologic and histologic findings in 149 patients. Seven percent of patients with normal samples were positive for HPV DNA, compared with 29% and 69% of patients with low- and high-grade squamous intraepithelial lesions (SILs), respectively. The performance of both assays increased the rate of HPV detection in low-grade lesions but not in high-grade cases. ViraPap was more sensitive than the ViraType in situ hybridization assay in high-grade lesions. The present investigation suggests that HPV DNA detection may be useful in separating confirmed lesions from histologically questionable biopsies.

Chromatographic resolution of tryptophan enantiomers with L-Leu-L-Leu-L-Leu peptide effects of mobile phase composition and chromatographic support.

Tryptophan enantiomers have been separated by zwitterion pair chromatography using L-leucine-L-leucine-L-leucine peptide as the zwitterion pairing agent. The peptide ligand is adsorbed onto an octadecylsilane support with excess ligand present in bulk solution. This article examines the roles of the hydrophobic matrix and the mobile phase components on tryptophan enantiomer binding and resolution. Capacity factors and enantioselectivites are given for both hydrophobic and hydrophilic matrices using mobile phases containing Leu-Leu-Leu peptide and/or salt. A decrease in selectivity upon the addition of mobile phase salt suggests that quadrupolar ion-pairing contributes to chiral recognition. Results indicate that binding is significantly reduced and separation is not achieved when Leu-Leu-Leu is coupled onto cross-linked or polymerized hydrophilic resins as well as onto macroporous polystyrene resin. However, resin-immobilized Leu-Leu-Asp-Leu-Leu-Leu, Leu-Leu-Glu-Leu-Leu-Leu, and Leu-Leu-Leu-Glu-Leu-Leu peptides, with ion-pairing sites designed to mimic the Leu-Leu-Leu-saturated C18 support, also do not resolve tryptophan enantiomers. This suggests the Leu-Leu-Leu structure is critical for enantiomer resolution. Because D- and L-tryptophan are separated in the absence of bulk Leu-Leu-Leu, chiral discrimination is believed to occur at the surface of the octadecylsilane support.

Noncompetitive immunoassays using bifunctional unilamellar vesicles or liposomes.

Small unilamellar vesicles (SUVs) functionalized with an enzyme label and with specific ligands for biological molecules are useful as signal enhancement vehicles in the development of enzyme-linked immunoadsorbent assays and other biosensor applications. Bifunctional vesicles were prepared by covalently attaching horseradish peroxidase (HRP) and an antibody to the outside of the lipid bilayer of an SUV. The reaction conditions were optimized to obtain 7-12 antibody molecules and 100-200 HRP molecules per vesicle. The enzyme retained 70-80% of its specific activity after immobilization, and the presence of immobilized proteins on the vesicle surface apparently increased the vesicle stability. To minimize the background signal and maximize the specific signal, the immunoassay protocol was optimized with respect to (1) the type and concentration of blocking agent, (2) the diluents for HRP-antibody-vesicles and sample, (3) the incubation period, and (4) the incubation temperature. The bifunctional vesicles were used in a noncompetitive immunoassay to detect d-dimer, a fibrin dimer formed at the early stages of thrombosis. A second conjugate, HRP-antibody, was prepared, characterized, and used as a control against which to compare the assay using vesicles. The assay results using vesicles led to a detection limit for d-dimer in human plasma 9 times lower than what was achieved using the conventional enzyme-antibody conjugate assay.

Preparation and characterization of bifunctional unilamellar vesicles for enhanced immunosorbent assays.

Small unilamellar phospholipid vesicles with covalently attached biotin and horseradish peroxidase (HRP) were prepared and characterized in terms of hydrodynamic diameter, amount and activity of immobilized enzyme, and number of biotin molecules on the outer vesicle surface. In addition, the specific adsorption of these bifunctional vesicles and commercially available biotin-labeled horseradish peroxidase (B-HRP) to antibiotin antibody (ABA) coated polystyrene microtiter plate wells was examined. At low antibody surface densities, the signal (delta A/min) generated by the vesicles adsorbed to the surface was approximately 100 times higher than the signal generated by B-HRP. It was also found that the biotin-conjugated vesicles were able to compete effectively with free biotin in solution for surface ABA sites. These results indicate that this type of vesicle may be used in competitive and sandwich-type enzyme-linked immunoassays to improve the detection limits, increase the signal, and decrease the reaction time necessary to detect a given analyte concentration in solution.

Competitive immunosorbent assays using ligand-enzyme conjugates bifunctional liposomes: theory and experiment.

Two models of immunoadsorbent assays are developed that describe the competitive adsorption of labeled antigen and unlabeled analyte to antibody binding sites immobilized on a solid surface. In the first model, a small labeled antigen and a small unlabeled analyte compete with only binding site limitations and no steric limitations. A multicomponent langmuir isotherm results that is sufficient to quantify competitive adsorption. This model can describe, with no adjustable parameters, the data of competitive assays for biotin using biotinylated horseradish peroxidase (B-HRP) over a wide range of anti-biotin antibody (ABA) surface densities. In the second model, the small unlabeled analyte competes with a large colloidal particle containing many antigens and enzyme labels attached to its surface. This model quantifies the steric interference that large particles can experience upon binding (large ligand effect) due to the lower probability of finding an available area of the right size to accommodate the larger adsorbent. This large ligand model also takes into account the increased probability of binding a large particle due to the larger number of antibody binding sites covered per collision. The resulting model is used to analyze the competitive assay data of biotin competing with liposomes to which many biotin and HRP molecules have been conjugated. This analysis is of interest because previous work has shown that these bifunctional liposomes can reduce the detection limit for antigens in bulk solution relative to assays performed with conventional small labeled antigens.

Application of antibody and fluorophore-derivatized liposomes to heterogeneous immunoassays for d-dimer.

Small unilamellar liposomes comprised of cholesterol and phospholipids, in which one of the lipids is labeled with a fluorophore, have been covalently functionalized with antibodies. The liposomes were conjugated with thousands of fluorescein molecules and 10-20 monoclonal antibodies per liposome. These bifunctional liposomes were used in a direct (sandwich-type) immunoassay for the detection of thromboembolic disorders by assaying for d-dimer. D-dimer is the final and the smallest proteolytic product in the degradation of cross-linked fibrin by the plasma protein plasmin. The immunoassay using liposomes was compared to a conventional immunoassay that uses a fluor-antibody conjugate. The liposomes, by virtue of having thousands of fluorophores coupled to one liposome in contrast to one or a few reporter molecules in the conventional fluor-antibody conjugate, performed better on two counts: (1) they lowered the detection limit by a factor of 120 and (2) they provided a 1 order of magnitude amplification in signal. The minimum detectable concentration (MDC) of d-dimer was 5.6 ng/mL with the liposomal assay as compared to an MDC of 674 ng/mL with conventional fluor-antibody conjugate. The results of fluorescence assays were also compared with the results obtained by Singh et al. (Biotechnol. Prog. 1995, 11, 333-341) in an enzyme immunoassay developed using liposomes. These results demonstrate the potential of liposomes in lowering detection limits and increasing the sensitivity of immunoassays.

Competitive immunosorbent assays for biotin using bifunctional unilamellar vesicles.

Competitive immunosorbent assays for the model antigen biotin were performed using both unilamellar vesicles with covalently attached biotin and horseradish peroxidase (HBVs) and commercially available biotin-labeled horseradish peroxidase (B-HRP) as the enzyme-labeled antigen. The assays were performed using anti-biotin antibody (ABA) surface densities ranging from one-tenth to full monolayer coverage. It was found that assays using HBVs strongly depended on the antibody surface density, while assays using B-HRP were relatively insensitive to the antibody surface density. The HBV assay dependence on the ABA surface density was most likely due to multiple point attachment of vesicles to the surface. The lowest detectable antigen concentration (least detectable dose) for vesicles (approximately 10(-9) M) was an order of magnitude lower than the value found for B-HRP (approximately 10(-8) M). The sensitivity (slope of the response vs biotin concentration curve) of assays with B-HRP was comparable to the sensitivity of assays with HBVs at low antibody surface density, probably due to less extensive multipoint attachment. It was also found that assays could be performed with vesicles at antibody surface densities that were at least 5 times lower, in terms of the bulk antibody concentrations used to coat the wells, than antibody surface densities at which B-HRP gave comparable signals (approximately 1 delta A/min).

Affinity precipitation of proteins by surfactant-solubilized, ligand-modified phospholipids.

The use of ligand-modified phospholipids solubilized in aqueous solution by nonionic surfactant for affinity precipitation of proteins is described. Avidin was precipitated by contact with solutions in which dimyristoylphosphatidylethanolamine (DMPE) functionalized with biotin (DMPE-B) was solubilized in octaethylene glycol mono-n-dodecyl ether (C12E8) solutions. The nonionic surfactant solubilizes the phospholipid in micelles above its critical micelle concentration (CMC) and in small submicellar aggregates below this concentration. At C12E8 concentrations significantly exceeding its CMC, determined to be about 100 microM, precipitation of avidin by solubilized DMPE-B is not observed. In this regime, binding of protein by DMPE-B was monitored by a hyperchroic shift in the protein's UV-visible spectrum at 231.5 nm. The data were analyzed using a model that considers the four binding sites on the protein to be independent and identical in binding strength for DMPE-B. Below the CMC of C12E8, precipitation is observed and is monitored by increasing turbidity of the solution. The kinetics of precipitation and the aggregate size measured by quasielastic light scattering were analyzed using Smoluchowski kinetics and the Mie scattering theory. These results help establish more completely the factors that influence the precipitation of proteins by ligand-modified phospholipids, and they are helpful in specifying conditions for the precipitation of other proteins.

Studies of the binding of alpha-lactalbumin to immobilized peptide ligands.

The present work investigates the mechanism of binding of alpha-lactalbumin to the peptide ligand WHWRKR and its variants HWRKR and acetylated WHWRKR immobilized on a polymethacrylate chromatographic resin. The presence of two temperature-dependent binding mechanisms and one temperature-independent mechanism was demonstrated. Injections of different forms of alpha-lactalbumin (apo-alpha-lactalbumin, D87A mutant alpha-lactalbumin) displayed similar behaviors when compared to native alpha-lactalbumin, while lysozyme showed little or no binding to the WHWRKR and AcWHWRKR resins. An alternative process for isolation of alpha-lactalbumin from WPI was shown, using consecutive injections of WPI with limited elution.

Inhibition of plasma butyrylcholinesterase activity in the lizard Gallotia galloti palmae by pesticides: a field study.

A field study was performed to evaluate the effect of exposure to organophosphorus (OP) and carbamate (CB) pesticides on the lizard Gallotia galloti palmae. Butyrylcholinesterase (BChE) activity was measured in the plasma of 420 lizards collected from agricultural and reference areas on the Island of La Palma (Canary Islands, Spain) in two sampling periods. Exposure to cholinesterase-inhibiting pesticides was evaluated by a statistical criterion based on a threshold value (two standard deviations below the mean enzyme activity) calculated for the reference group, and a chemical criterion based on the in vitro reactivation of BChE activity using pyridine-2-aldoxime methochloride (2-PAM) or after water dilution of the sample. Mean (+/- SD) BChE activity for lizards from agricultural areas was significantly lower (Fuencaliente site = 2.00 +/- 0.98 micromol min(-1) ml(-1), Tazacorte site = 2.88 +/- 1.08) than that for lizards from the reference areas (Los Llanos site = 3.06 +/- 1.17 micromol min(-1) ml(-1), Tigalate site = 3.96 +/- 1.62). According to the statistical criterion, the number of lizards with BChE depressed was higher at Fuencaliente (22% of males and 25.4% of females) than that sampled at Tazacorte (7.8% of males and 6.2% of females). According to the chemical criterion, Fuencaliente also yielded a higher number of individuals (112 males and 47 females) with BChE activity inhibited by both OP and CB pesticides. CBs appeared to be the pesticides most responsible for BChE inhibition because most of the samples showed reactivation of BChE activity after water treatment (63.3% from Fuencaliente and 29% from Tazacorte). We concluded that the use of reactivation techniques on plasma BChE activity is a better and more accurate method for assessing field exposure to OP/CB pesticides in this lizard species than making direct comparisons of enzyme activity levels between sampling areas.

[Atrioventricular nodal reentrant tachycardia as a trigger for atrial fibrillation]. / Taquicardia reentrante intranodal como inductora de fibrilación auricular.

We report the case of a 43 year-old male with a long history of paroxysmal palpitations aborted by vagal manoeuvres, where atrial fibrillation was the only documented arrhythmia. During the electrophysiological study an AV nodal reentrant tachycardia was demonstrated with rapid degeneration into atrial fibrillation. After slow pathway ablation, nodal tachycardia became non-inducible. No palpitations were reported and no arrhythmic event was recorded after a follow-up of 20 months. In selected cases, the electrophysiological study could reveal potentially curable causes of atrial fibrillation.

[Fever and abdominal pain. A case of familial mediterranean fever]. / Fiebre y dolor abdominal. Un caso de fiebre mediterránea familiar.

Familial mediterranean fever (FMF) is an hereditary disease transmitted in an autosomal recessive way and characterized by recurrent and brief episodes of fever and pain secondary to serositis. The pain is usually located in abdomen simulating an acute abdomen, and in thorax in the form of pleuritic pain. The most severe complication of the FMF is the development of amyloidosis being the main cause of death. This illness affects an specific ethnic group of the mediterranean area, but the prevalence in our area is low. We present the case of a 30 years old man with recurrent thoracic and abdominal pain, whose final diagnostic was FMF. Insisting on the difficulty that it was recognize this proper illness.

Prognostic factors in tympanoplasty: a statistical evaluation.

In a group of 52 patients with chronic otitis media that underwent a myringoplasty, pressure equalization mucociliary clearance of the Eustachian tube and degree of pneumatisation of the mastoid have been studied, and their statistical relationship with surgical outcome evaluated. The only statistically being significant correlation was mucociliary clearance time.