A broadly resolved molecular phylogeny of New Zealand cheilostome bryozoans as a framework for hypotheses of morphological evolution.

Larger molecular phylogenies based on ever more genes are becoming commonplace with the advent of cheaper and more streamlined sequencing and bioinformatics pipelines. However, many groups of inconspicuous but no less evolutionarily or ecologically important marine invertebrates are still neglected in the quest for understanding species- and higher-level phylogenetic relationships. Here, we alleviate this issue by presenting the molecular sequences of 165 cheilostome bryozoan species from New Zealand waters. New Zealand is our geographic region of choice as its cheilostome fauna is taxonomically, functionally and ecologically diverse, and better characterized than many other such faunas in the world. Using this most taxonomically broadly-sampled and statistically-supported cheilostome phylogeny comprising 214 species, when including previously published sequences, and 17 genes (2 nuclear and 15 mitochondrial) we tested several existing systematic hypotheses based solely on morphological observations. We find that lower taxonomic level hypotheses (species and genera) are robust while our inferred trees did not reflect current higher-level systematics (family and above), illustrating a general need for the rethinking of current hypotheses. To illustrate the utility of our new phylogeny, we reconstruct the evolutionary history of frontal shields (i.e., a calcified body-wall layer in ascus-bearing cheilostomes) and ask if its presence has any bearing on the diversification rates of cheilostomes.

[Eustachian tube function tests: an update]. / Aktueller Stand der Tubenfunktionsdiagnostik: Ein Update.

There are many diverse methods for the assessment of Eustachian tube (ET) function. Clinical studies have demonstrated good results for several clinical tests, tympanometry and a number of manometric approaches, such as the nine-step test. The relevance of tubomanometry according to Estève requires further investigation. MRI studies in particular have considerably enhanced our knowledge of ET function. Endoscopy and conventional Schüller radiography are routinely employed in the clinic. The pressure chamber is ideal for simulating the most diverse test conditions, but it is only used experimentally. Sonotubometry has both the potential and the necessary level of technical advancement for a broader clinical application. The majority of investigations have demonstrated that there is no single valid method. There is currently no technique available that is capable of reflecting all aspects of ET function. Although several methods have found clinical application, a commonly accepted golden standard for ET testing still has to be established. Further clinical studies are necessary to generate an adequate amount of data pertaining to the various ET function tests.

Prevalence of obesity in 6- and 9-year-old children living in Central-North Italy. Analysis of determinants and indicators of risk of overweight.

The objective of our article is to survey the prevalence of overweight and obesity among 6- and 9-year-old children in Emilia-Romagna, a region of Central-North Italy, and to study the eating habits and behaviours of these children and their families. During 2003 and 2005, we analysed a stratified sample of the general population of children attending pre-school (2681 children aged 6 years) and primary school (2955 children aged 9 years). Their height and weight were measured by healthcare workers. In the 6-year-old children, information concerning their eating habits was collected by means of a questionnaire completed by their parents. The prevalence of overweight was 16.5% in 6-year-old children and 20.6% in 9-year-old children. The increase of overweight from 6- to 9-year-old children was observed in males (13.5% in 6-year-old/21.3% in 9-year-old boys), but not in females. The prevalence of obesity was 8.9% in children aged 6 years and 9.0% in those aged 9 years, and it was higher in comparison with Italian surveys carried out in 1993 and in 2001: 7.5% in 6-year-old and 7.8% in 9-year-old children in 1993, and 6.6% in 6-year-old and 7.2% in 9-year-old children in 2001. In pre-school children, overweight and obesity were closely influenced by the education level, occupation and nutritional status of the parents.

Stress-modulated remodeling of a non-homogeneous body.

Many soft tissues, and arteries in primis, exhibit residual stress after unloading, a characteristic related to the ability to self-organize their own constituents (cells and extracellular matrix proteins). This behavior can be theoretically predicted in a continuum mechanics framework assuming that the body self-remodels toward a homeostatic stress state. Open questions concern the characteristics of a stationary grown state, as dictated by the mechanical properties of the material and by the specific external load. In this paper, we illustrate a mathematical framework and we perform numerical simulations for the remodeling of a two-dimensional (axisymmetric) nonlinear elastic cylinder. In particular, we address the stress-modulated remodeling of the cylinder wall when local variations in the mechanical properties of the material occur. Our main result is that, as in one spatial dimension, the tendency of the system to homeostasis generates, thanks to the remodeling process, a residual stress that homogenizes the tension in the body under load. Possible physiological implications of this result are discussed in the final section.

Bilateral posterior semicircular canal aplasia and atypical paroxysmal positional vertigo: a case report.

Isolated congenital malformations of semicircular canals are rare abnormalities. Most inner ear abnormalities occur in syndromes and are associated with hearing loss. Unilateral or bilateral single aplasia of one semicircular canal does not usually result in vertigo, but these become clinically important if there are clinical complaints of vertigo. Computed tomography imaging and high resolution magnetic resonance imaging may reveal inner ear abnormalities. The case is presented here of a 46-year-old male with a 10-year history of recurrent positional vertigo with strong onset when changing position to the left side. Magnetic resonance imaging of the inner ear showed a bilateral posterior semicircular canal aplasia as well as an enlarged vestibule on both sides. Dix-Hallpike positional manoeuvre revealed a positional nystagmus in the left head-hanging position of short duration and latency of a few seconds. When rising, vertigo occurred, but no nystagmus was visible. The fast phase of the nystagmus was mainly vertical down-beating with a slight torsional component to the uppermost ear. Although benign paroxysmal vertigo of the anterior canal was suspected, physical therapy was not effective using a modified liberatory manoeuvre. Brandt-Daroff therapy was effective permanently.

Design of Bioprosthetic Aortic Valves using biaxial test data.

Bioprosthetic Aortic Valves (BAVs) do not have the serious limitations of mechanical aortic valves in terms of thrombosis. However, the lifetime of BAVs is too short, often requiring repeated surgeries. The lifetime of BAVs might be improved by using computer simulations of the structural behavior of the leaflets. The goal of this study was to develop a numerical model applicable to the optimization of durability of BAVs. The constitutive equations were derived using biaxial tensile tests. Using a Fung model, stress and strain data were computed from biaxial test data. SolidWorks was used to develop the geometry of the leaflets, and ABAQUS finite element software package was used for finite element calculations. Results showed the model is consistent with experimental observations. Reaction forces computed by the model corresponded with experimental measurements when the biaxial test was simulated. As well, the location of maximum stresses corresponded to the locations of frequent tearing of BAV leaflets. Results suggest that BAV design can be optimized with respect to durability.

Echistatin induces decrease of pp125FAK phosphorylation, disassembly of actin cytoskeleton and focal adhesions, and detachment of fibronectin-adherent melanoma cells.

B16-BL6 mouse melanoma cells cultured on fibronectin-coated dishes were detached by treatment with echistatin, an RGD-containing disintegrin. Echistatin was active at micromolar concentrations and was not cytotoxic. Its effect was dose-dependent and reversible. Sequential morphological changes leading to rounding up of the cells were detected by phase-contrast microscopy and by immunofluorescence analysis. A dramatic reduction in the number and size of focal adhesions and loss of cytoplasmic actin filaments were observed well before cell detachment occurred. Echistatin treatment down-regulated the phosphorylation of pp125FAK in fibronectin-adherent cells in a dose- and time-dependent fashion. The reduction of pp125FAK phosphorylation preceded cell detachment and occurred even in the presence of orthovanadate, an inhibitor of protein tyrosine phosphatases. These results suggest that echistatin detaches cells from the fibronectin substratum by inducing a decrease of pp125FAK phosphorylation and that echistatin acts by inhibiting protein tyrosine kinase activity rather than activating protein tyrosine phosphatases.

Diagnosis and staging of head and neck cancer: a comparison of modern imaging modalities (positron emission tomography, computed tomography, color-coded duplex sonography) with panendoscopic and histopathologic findings.

OBJECTIVE: To compare the clinical value of positron emission tomography (PET) using fludeoxyglucose F 18, computed tomography (CT), color-coded duplex sonography (CCDS), and panendoscopy in the detection and staging of head and neck cancer. DESIGN: Prospective nonrandomized controlled study. SETTING: Medical school. PATIENTS: Convenience sample of 50 patients with suspected primary or recurrent head and neck cancer. INTERVENTION: Biopsy, tumor surgery. MAIN OUTCOME MEASURES: Information of diagnostic procedures compared with histopathologic features. RESULTS: Both PET and panendoscopy had a sensitivity of 95% and 100% for detection of primary tumor or recurrent carcinomas, respectively. Specificity for PET and panendoscopy was 92% and 85% in primary tumors and 100% and 80% in recurrent carcinoma, respectively. Sensitivity of CCDS and CT was 74% and 68% in primary tumors and 67% and 63% in recurrent carcinomas, respectively. Specificity was 75% and 69% in primary tumors and 100% and 80% in recurrent neoplasms. When assessing neck nodes, all imaging procedures exhibited identical sensitivity (84%). Specificity was 90%, 96%, and 88% in PET, CT, and CCDS, respectively. In recurrent lymph node metastases, sensitivity was 100%, 67%, and 67% and specificity was 87%, 91%, and 87% for PET, CT, and CCDS, respectively. CONCLUSIONS: Positron emission tomography was the most reliable imaging procedure in the detection of primary tumor and recurrent carcinomas localized in the head and neck region. Owing to its limited anatomical depiction, it cannot as yet replace other diagnostic procedures in preoperative planning but does contribute valuable complementary diagnostic information. Computed tomograpy may have difficulties in identifying recurrent carcinomas. For routine diagnosis of nodal spread in the neck, CCDS is recommended. Panendoscopy is a valuable diagnostic procedure that can provide key information in cases of superficial mucosal tumor involvement. Arch Otolaryngol Head Neck Surg. 2000;126:1457-1461

[Nuclear magnetic resonance tomography imaging and functional diagnosis of the eustachian auditory tube]. / Kernspintomographische Darstellung und Funktionsdiagnostik der Tuba auditiva Eustachii.

PURPOSE: To develop and evaluate a protocol for the anatomic depiction and functional testing of the auditory tube with the use of MR imaging. METHODS: Eleven volunteers were included into this study. For the morphological assessment, the imaging protocol included axial and coronal T2-weighted turbo-spin echo sequences (TR/TE = 3194/100 ms) and a T1-weighted gradient echo sequence (TR/TE = 42/4.6 ms). For the functional test a dynamic turbo-gradient echo sequence (TFE) with spectral fat suppression (TR/TE = 15/6.2 ms; 4 sec) was obtained using the single slice technique before and during the Valsalva manoeuvre. RESULTS: With multi-slice sequences, the osseous part of the auditory tube, the tubal cartilage (middle and lateral lamina), the ciliated epithelium, Ostmann's adipose body and the levator and tensor veli palatini muscles were delineated in all cases. During the Valsalva test, opening of the auditory tube was demonstrated in 20 of the 22 investigated sides using the dynamic TFE single slice sequence. CONCLUSIONS: The introduced MRI protocol allow visualization of the opening of the auditory tube and provides detailed anatomical information of the nasopharynx. Comprehensive morphological and functional evaluation of the auditory tube becomes possible within a single examination'.

Diagnostic evaluation of malignant head and neck cancer by F-18-FDG PET compared to CT/MRI.

AIM: Evaluation of F-18-FDG PET in comparison to CT/MRI as diagnostic tool in primary and recurrent head and neck cancer. METHODS: 78 F-18-FDG PET studies were performed in 71 patients with known or suspected primary (n = 48) or recurrent (n = 30) head and neck cancer and compared to CT (n = 75) or MRI investigations (n = 3) concerning detection of the primary or recurrent tumor and detection of regional lymph node metastases in the ipsilateral and contralateral neck sides. Glucose uptake (SUV) of PET findings was correlated to tumor location, grading and dignity of the lesion. RESULTS: Sensitivity and specificity for PET in detection of primary tumors were 87%* and 67%, respectively (CT/MRI 67%* and 44%) (*p < 0.05), in detection of local recurrence 86% and 75%, respectively (CT/MRI 57% and 92%), in detection of necks affected by lymph node metastases 80% and 92%, respectively (CT/MRI 80% and 84%). Laryngeal, buccal (cheek) and salivary gland tumors had significant lower glucose uptake (SUV) when compared to tumors of the hypopharynx (p < 0.05). G1-tumors (mean SUV 4.26) had significant (p < 0.05) lower glucose uptake when compared to G2- and G3-tumors (mean SUV 7.73 and 8.19, respectively). Mean SUV of malignant PET findings (7.88) was significant (p < 0.05) higher than mean SUV of benign PET findings (5.70). However, a SUV threshold to improve diagnostic accuracy could not be defined. CONCLUSIONS: F-18-FDG PET is significantly more accurate than CT/MRI for detection of head and neck cancer. Both methods are valuable for detection of cervical lymph node metastases. Glucose uptake shows correlation to histological grading. A quantitative SUV analysis does not improve diagnostic accuracy.

Wear of polyethylene cups in total hip arthroplasty: a parametric mathematical model.

This paper presents a parametric mathematical model of the head-cup wear coupling in total hip arthroplasty (THA). The model evaluates the dependence of acetabular volumetric wear upon the characteristic parameters of patient and hip prosthesis. Archard's law is assumed to calculate the wear coupling behaviour. The wear factor is taken from pin-on-disc wear tests as a function of materials and finishing of the articular joint. The forces acting on the hip joint are taken from experimental data found in the literature whilst the load distribution is calculated under the hypotheses of perfectly rigid ideal wear coupling. The sliding distance is obtained by combining the three elementary displacements -- due to rotations around the three axes -- at the generic bearing surface location. The simulations show that the polymeric wear volume per step cycle decreases ranging from fast walking speeds to low running speeds, it increases linearly with patient body weight and with femoral head diameter, it decreases slightly for positive variations of the socket inclination angle and it increases exponentially with femoral head roughness. The volumetric wear rate per year calculated for a standard reference patient is 5.8 mm3. The relevant iso-wear maps show a marginal pattern with the maximum located near the cup superior borderline. At the instant of peak load, the iso-stress maps show a paracentral pattern with the maximum superior to the cup polar point, and the iso-sliding distance maps show a marginal pattern with two maxima located near the cup's superior and inferior borderlines.

Assessment of the influence of the compliant aortic root on aortic valve mechanics by means of a geometrical model.

In recent years several researchers have suggested that the changes in the geometry and angular dimensions of the aortic root which occur during the cardiac cycle are functional to the optimisation of aortic valve function, both in terms of diminishing leaflet stresses and of fluid-dynamic behaviour. The paper presents an analytical parametric model of the aortic valve which includes the aortic root movement. The indexes used to evaluate the valve behaviour are the circumferential membrane stress and the stress at the free edge of the leaflet, the index of bending strain, the bending of the leaflet at the line attachment in the radial and circumferential directions and the shape of the conduit formed by the leaflets during systole. In order to evaluate the role of geometric changes in valve performance, two control cases were considered, with different reference geometric configuration, where the movement of the aortic root was ignored. The results obtained appear consistent with physiological data, especially with regard to the late diastolic phase and the early ejection phase, and put in evidence the role of the aortic root movement in the improvement of valve behaviour.

Fluid-structure interaction within realistic three-dimensional models of the aneurysmatic aorta as a guidance to assess the risk of rupture of the aneurysm.

Abdominal aortic aneurysm (AAA) disease is a degenerating process whose ultimate event is the rupture of the vessel wall. Rupture occurs when the stresses acting on the wall rise above the strength of the AAA wall tissue. The complex mechanical interaction between blood flow and wall dynamics in a three dimensional custom model of a patient AAA was studied by means of computational coupled fluid-structure interaction analysis. Real 3D AAA geometry is obtained from CT scans image processing. The results provide a quantitative local evaluation of the stresses due to local structural and fluid dynamic conditions. The method accounts for the complex geometry of the aneurysm, the presence of a thrombus and the interaction between solid and fluid. A proven clinical efficacy may promote the method as a tool to determine factual aneurysm risk of rupture and aid the surgeon to refer elective surgery patients.

A new pulsatile blood pump for adult cardiopulmonary bypass: design criteria and preliminary fluid dynamic evaluation.

A new pulsatile pumping device for adult cardiopulmonary bypass has been designed. Its main characteristic consists in having a fully disposable pumping head, since polymeric materials have been adopted for the housing as well as for the built-in inlet and outlet valves. Furthermore, the valves show an innovative design, as they are ring-shaped and accomplish their task by virtue of their elastic deformability. The design phase of the pumping head and the first fluid dynamic evaluations have been performed by numerical methods. Particularly, a three-dimensional CAD model of the pumping head (in the current configuration) is presented in this paper. On the basis of this model, computational fluid dynamic analysis of the hydraulic behaviour has been performed for some components. The obtained results show complex velocity patterns in the pumping chamber during the filling phase as well as limited pressure gradients across the inlet valve.

Optimisation of a stentless valve prosthesis based on an analytic parametric model of the aortic valve.

An analytical mathematical model of a stentless aortic valve has been implemented. The valve is characterised by a trileaflet geometry, cylindrical leaflets; the aortic root is schematised by a conical surface which includes the leaflet attachments. The model is defined through six geometric parameters: the base radius, the valve height, the commissure radius, the leaflet radial, circumferential and attachment line lengths. Five performance indexes have been used to optimise the valve geometry, namely: the systolic area, the leaflet circumferential stress in diastole, the leaflet bending strain in systole and two bending angles related to the rotation of the leaflets from the diastolic to the systolic configuration. The sensitivity analysis is carried out which can identify the influence of each geometric parameter on the performance indexes adopted for the optimum valve design. The analysis of the results provides the geometric configuration which optimises the overall function of the valve throughout the cardiac cycle.

An assisted automated procedure for vessel geometry reconstruction and hemodynamic simulations from clinical imaging.

In this paper a method is described to obtain realistic 3-D geometric models of vascular districts from clinical tomographic 3-D images. The aim is the simulation of individual local hemodynamics by means of computational fluid-dynamics (CFD). As a test case, the method is applied to the carotid bifurcation. Attention is focused on the minimisation of the time demanding costs. The proposed procedure has been automated whenever possible and takes about 2h from the acquisition of the images to the attainment of the simulation results, a time lapse compatible with diagnostic exigency.

A microstructurally motivated model of arterial wall mechanics with mechanobiological implications.

Through mechanobiological control of the extracellular matrix, and hence local stiffness, smooth muscle cells of the media and fibroblasts of the adventitia play important roles in arterial homeostasis, including adaptations to altered hemodynamics, injury, and disease. We present a new approach to model arterial wall mechanics that seeks to define better the mechanical environments of the media and adventitia while avoiding the common prescription of a traction-free reference configuration. Specifically, we employ the concept of constituent-specific deposition stretches from the growth and remodeling literature and define a homeostatic state at physiologic pressure and axial stretch that serves as a convenient biologically and clinically relevant reference configuration. Information from histology and multiphoton imaging is then used to prescribe structurally motivated constitutive relations for a bi-layered model of the wall. The utility of this approach is demonstrated by describing in vitro measured biaxial pressure-diameter and axial force-length responses of murine carotid arteries and predicting the associated intact and radially cut traction-free configurations. The latter provides a unique validation while confirming that this constrained mixture approach naturally recovers estimates of residual stresses, which are fundamental to wall mechanics, without the usual need to prescribe an opening angle that is only defined conveniently on cylindrical geometries and cannot be measured in vivo. Among other findings, the model suggests that medial and adventitial stresses can be nearly uniform at physiologic loads, albeit at separate levels, and that the adventitia bears increasingly more load at supra-physiologic pressures while protecting the media from excessive stresses.

Mechano-biology in the thoracic aortic aneurysm: a review and case study.

An aortic aneurysm is a permanent and localized dilatation of the aorta resulting from an irreversible loss of structural integrity of the aortic wall. The infrarenal segment of the abdominal aorta is the most common site of aneurysms; however, they are also common in the ascending and descending thoracic aorta. Many cases remain undetected because thoracic aortic aneurysms (TAAs) are usually asymptomatic until complications such as aortic dissection or rupture occurs. Clinical estimates of rupture potential and dissection risk, and thus interventional planning for TAAs, are currently based primarily on the maximum diameter and growth rate. The growth rate is calculated from maximum diameter measurements at two subsequent time points; however, this measure cannot reflect the complex changes of vessel wall morphology and local areas of weakening that underline the strong regional heterogeneity of TAA. Due to the high risks associated with both open and endovascular repair, an intervention is only justified if the risk for aortic rupture or dissection exceeds the interventional risks. Consequently, TAAs clinical management remains a challenge, and new methods are needed to better identify patients for elective repair. We reviewed the pathophysiology of TAAs and the role of mechanical stresses and mathematical growth models in TAA management; as a proof of concept, we applied a multiscale biomechanical analysis to a case study of TAA.

Caloric stimulation with near infrared radiation does not induce paradoxical nystagmus.

Near infrared radiation can be used for warm stimulation in caloric irrigation of the equilibrium organ. Aim of this study was to determine whether near infrared radiation offers effective stimulation of the vestibular organ, whether it is well tolerated by the patients and especially whether it is a viable alternative to warm air stimulation in patients with defects of the tympanic membrane and radical mastoid cavities. Patients with perforations of the tympanic membrane (n = 15) and with radical mastoid cavities (n = 13) were tested both with near infrared radiation and warm dry air. A caloric-induced nystagmus could be seen equally effectively and rapidly in all patients. Contrary to stimulation with warm dry air, no paradoxical nystagmus was observed following caloric irrigation with a warm stimulus (near infrared radiation). Results of a questionnaire showed excellent patient acceptance of near infrared stimulation with no arousal effects or unpleasant feeling. In conclusion, near infrared radiation proved to be an alternative method of caloric irrigation to warm dry air in patients with tympanic membrane defects and radical mastoid cavities. Near infrared radiation is pleasant, quick, contact free, sterile and quiet. With this method an effective caloric warm stimulus is available. If near infrared radiation is used for caloric stimulus no evaporative heat loss occurs.