Three-dimensional morphological condylar and mandibular changes in a patient with juvenile idiopathic arthritis: Interdisciplinary treatment

Temporomandibular joint (TMJ) involvement is common but usually delayed in patients with juvenile idiopathic arthritis (JIA). We describe the case of a JIA patient with bilateral TMJ involvement, mandibular retrognathia, bone erosion, and severely restricted mouth opening. The use of cone beam computed tomography and a 3D diagnostic protocol in young patients with JIA provides reliable, accurate and precise quantitative data and images of the condylar structures and their dimensional relationships. Analgesics and conventional disease modifying antirheumatic drugs were ineffective, but interdisciplinary treatment with etanercept and a Herbst functional appliance improved functional TMJ movement and bone resorption

Ultrasonography role for diagnosis of temporomandibular joint disorders

Aim: The aim of this study is to show the importance and reliability of ultrasonography (US) in the diagnosis of the temporomandibular disorders (TMJ) in patients affected by orofacial pain and dysfunction with dentofacial and skeletal malocclusions. Materials and Methods: 30 patients have been assessed by ultrasonographic exams. Us was performed with a 11-18 MHz linear transducer. US offers specific advantages because it is non-invasive, does not require sedation or general anesthesia (which facilitates examinations for follow-up), is quickly accessible bedside, and is easy to combine with clinical assessment (interactivity). Agitation of the patient is rarely a problem, as MRI and multiple locations can be assessed during a single session. Furthermore, modern high-frequency US transducers used by experienced US examiners can provide unsurpassed resolution of the superficial musculoskeletal structures. Results: Were detected morphological alterations and positions of mandibular condyles in the glenoid fossa, condylar synovitis, disc displacement and joint effusion. Conclusions: Ultrasonography is a noninvasive and inexpensive diagnostic procedure that can be suggested for the evaluation of TMJ disorders, with particular accuracy in the detection of disc displacement and joint effusion. Limitations are especially related to the scarce accessibility of the medial part of the TMJ structures, and the need for trained and calibrated operators

3D Cone Beam CT analysis of osteophytic neoformations in the temporomandibular joint

Aim: The aim is to show the usefulness of Cone Beam Computed Tomography (CBCT) in the study of the temporomandibular joint (TMJ) of patients with Rheumatoid Arthritis (RA), especially if by CT scans reveal the presence of osteophytic growths otherwise not visible with conventional radiographic techniques. Materials and Methods: Osteophyte is the medical term for a bone formation attempt to increase the articular surface of the load, it is the attempt to repair what the articulation performs to compensate for a bone defect or damage joint surfaces due to arthritis or trauma. Results: The examination CBCT allows accurate morphological analysis of articular surfaces in the three planes of space TMJ, not previously possible with traditional two-dimensional X-ray methods. The analysis highlights both the changes on surfaces such as cortical erosions, flattening, sclerosis, osteophytes and joint space narrowing, and changes in mineralization of bone considered. Conclusions: In Ra patients, the TMJ is commonly affected, but the diagnosis is often delayed due to lack of symptoms. In these cases, an CBCT provides the clinician with the advantage of highlighting condylar lesions as small scale and allows to establish appropriate therapy at an early stage, reducing complications for these patients

Spontaneous symmetry breaking in amnestically induced persistence

We investigate a recently proposed non-Markovian random walk model characterized by loss of memories of the recent past and amnestically induced persistence. We report numerical and analytical results showing the complete phase diagram, consisting of 4 phases, for this system: (i) classical nonpersistence, (ii) classical persistence (iii) log-periodic nonpersistence and (iv) log-periodic persistence driven by negative feedback. The first two phases possess continuous scale invariance symmetry, however log-periodicity breaks this symmetry. Instead, log-periodic motion satisfies discrete scale invariance symmetry, with complex rather than real fractal dimensions. We find for log-periodic persistence evidence not only of statistical but also of geometric self-similarity.Comment: 4 pages, 2 color fig

Amnestically induced persistence in random walks

We study how the Hurst exponent $\alpha$ depends on the fraction $f$ of the total time $t$ remembered by non-Markovian random walkers that recall only the distant past. We find that otherwise nonpersistent random walkers switch to persistent behavior when inflicted with significant memory loss. Such memory losses induce the probability density function of the walker's position to undergo a transition from Gaussian to non-Gaussian. We interpret these findings of persistence in terms of a breakdown of self-regulation mechanisms and discuss their possible relevance to some of the burdensome behavioral and psychological symptoms of Alzheimer's disease and other dementias.Comment: 4 pages, 3 figs, subm. to Phys. Rev. Let

Delocalization in harmonic chains with long-range correlated random masses

We study the nature of collective excitations in harmonic chains with masses exhibiting long-range correlated disorder with power spectrum proportional to $1/k^{\alpha}$, where $k$ is the wave-vector of the modulations on the random masses landscape. Using a transfer matrix method and exact diagonalization, we compute the localization length and participation ratio of eigenmodes within the band of allowed energies. We find extended vibrational modes in the low-energy region for $\alpha > 1$. In order to study the time evolution of an initially localized energy input, we calculate the second moment $M_2(t)$ of the energy spatial distribution. We show that $M_2(t)$, besides being dependent of the specific initial excitation and exhibiting an anomalous diffusion for weakly correlated disorder, assumes a ballistic spread in the regime $\alpha>1$ due to the presence of extended vibrational modes.Comment: 6 pages, 9 figure

A radiological visual scale to predict the potentially recruitable lung in ALI/ARDS patients

Introduction In ALI/ARDS patients the amount of potentially recruitable lung is extremely variable and it is poorly predictable by the changes of oxygenation, carbon dioxide or compliance during a PEEP trial [1]. At the present time the gold standard to compute the lung recruitability is the quantitative lung CT scan, in which each lung image, after being manually drawn, is analyzed by dedicated software. However, this is both a laborious and time-consuming technique. The aim of this study was to evaluate the ability of a visual radiological scale compared with lung CT scan analysis to predict the lung recruitability in ALI/ARDS patients. Methods A whole lung CT scan was performed at 5 and 45 cmH2O airway pressure. For CT scan analysis each lung image was manually outlined and analyzed by a dedicated software. The potentially recruitable lung was defi ned as the proportion of the nonaerated lung tissue in which aeration was restored [1]. For radiological visual scale analysis, two radiologists performed a blinded evaluation of the consolidation/collapsed areas in each lobe by visual inspection [2]. The overall lung change in consolidation/collapsed was obtained by the sum of each lobe and computed as the diff erence between the two conditions. Results Twenty-four ALI/ARDS patients (age 59 \ub1 15 years, BMI 26 \ub1 4 kg/m2, PaO2/FiO2 170 \ub1 60, PEEP 10 \ub1 2 cmH2O) were enrolled. The percentage of potentially recruitable lung was 16.2 \ub1 7.1% and 14.7 \ub1 7.0%, computed by CT scan and by the visual radiological scale, respectively. The mean diff erence between CT scan analysis and visual radiological analysis was 3.3 \ub1 4.6% (median: 2.91, interquartile range: 0.38 to 6.56). The error of the visual method was lower than 5% in 14 patients (58.3%), between 5% and 10% in eight patients (33.3%) and between 10% and 15% in two patients (8.3%). Conclusions The application of a radiological visual scale is able to predict the amount of potentially recruitable lung similarly to those obtained by a dedicated software avoiding the need of manually drawing each lung image. References 1. Gattinoni L, et al.: N Engl J Med 2006, 354:1775-1786. 2. Pierce RJ, et al.: Thorax 1980, 35:773-780

Strain threshold for ventilator-induced lung injury

Introduction Unphysiological lung strain (tidal volume/functional residual capacity, TV/FRC) may cause ventilator-induced lung injury (VILI) [1]. Whether VILI develops proportionally to the applied strain or only above a critical threshold remains unknown. Methods In 20 healthy, mechanically ventilated pigs, FRC and lung weight were measured by computed tomography. Animals were then ventilated for up to 54 hours with a TV set to produce a predetermined strain. At the end, lung weight was measured with a balance. VILI was defi ned as fi nal lung weight exceeding the initial one. Results Lung weight either did not increase at all (no-VILI group; lung weight change \u201373 \ub1 42 g, n = 9) or markedly augmented (VILI group; 264 \ub1 80 g, n = 11). In the two groups, strain was 1.38 \ub1 0.68 and 2.16 \ub1 0.50 (P <0.01), respectively. VILI occurred only when lung strain reached or exceeded a critical threshold, between 1.5 and 2.1 (Figure 1). Conclusions In animals with healthy lungs VILI only occurs when lung strain exceeds a critical threshold. Reference 1. Gattinoni L, Carlesso E, Cadringher P, et al.: Physical and biological triggers of ventilator-induced lung injury and its prevention [review]. Eur Respir J 2003, 22(Suppl 47):15s-25s

Magnon delocalization in ferromagnetic chains with long-range correlated disorder

We study one-magnon excitations in a random ferromagnetic Heisenberg chain with long-range correlations in the coupling constant distribution. By employing an exact diagonalization procedure, we compute the localization length of all one-magnon states within the band of allowed energies $E$. The random distribution of coupling constants was assumed to have a power spectrum decaying as $S(k)\propto 1/k^{\alpha}$. We found that for $\alpha < 1$, one-magnon excitations remain exponentially localized with the localization length $\xi$ diverging as 1/E. For $\alpha = 1$ a faster divergence of $\xi$ is obtained. For any $\alpha > 1$, a phase of delocalized magnons emerges at the bottom of the band. We characterize the scaling behavior of the localization length on all regimes and relate it with the scaling properties of the long-range correlated exchange coupling distribution.Comment: 7 Pages, 5 figures, to appear in Phys. Rev.