Acute testicular torsion in children: the role of sonography in the diagnostic workup

Acute testicular torsion in children is an emergency and has to be diagnosed urgently. Doppler sonography is increasingly used in imaging the acute scrotum. Nevertheless, in uncertain cases, surgical exploration is required. In this study, we attempted to define the role of Doppler sonography in the diagnostic workup of the acutely painful scrotum. All patients admitted between 1999 and 2005 with acute scrotal pain were included. After clinical assessment, patients were imaged by Doppler sonography with a ''high-end'' instrument. In cases of absent arterial perfusion of the testis in Doppler sonography, surgical exploration was carried out. Patients with unaffected perfusion were followed clinically by ultrasound for up to 2 years. Sixty-one infants and children aged 1 day to 17 years (median: 7.9 years) were included. In 14 cases, sonography demonstrated absent central perfusion, with abnormal parenchymal echogenicity in six. Absence of venous blood flow together with reduction of central arterial perfusion was found in one infant. In these 15 patients, surgical exploration confirmed testicular torsion. Among the other 46 patients, we found four cases with increased testicular perfusion and 27 with increased perfusion of the epididymis. In one infant, a testicular tumour was found sonographically, and orchiectomy confirmed diagnosis of a teratoma. Follow-up examinations of the conservatively treated patients showed good clinical outcome with physiologic central perfusion as well as normal echogenic pattern of both testes. No case of testicular torsion was missed. By means of Doppler sonography, an unequivocal statement regarding testicular perfusion was possible in all cases. The initial Doppler diagnosis was confirmed by operative evaluation and follow-up ultrasound. Testicular torsion can therefore be excluded by correctly performed ultrasound with modern equipment.

Biomechanical analysis of torsion and shear forces in lumbar and lumbosacral spine segments of nonchondrodystrophic dogs

OBJECTIVE: To determine stiffness and load-displacement curves as a biomechanical response to applied torsion and shear forces in cadaveric canine lumbar and lumbosacral specimens. STUDY DESIGN: Biomechanical study. ANIMALS: Caudal lumbar and lumbosacral functional spine units (FSU) of nonchondrodystrophic large-breed dogs (n=31) with radiographically normal spines. METHODS: FSU from dogs without musculoskeletal disease were tested in torsion in a custom-built spine loading simulator with 6 degrees of freedom, which uses orthogonally mounted electric motors to apply pure axial rotation. For shear tests, specimens were mounted to a custom-made shear-testing device, driven by a servo hydraulic testing machine. Load-displacement curves were recorded for torsion and shear. RESULTS: Left and right torsion stiffness was not different within each FSU level; however, torsional stiffness of L7-S1 was significantly smaller compared with lumbar FSU (L4-5-L6-7). Ventral/dorsal stiffness was significantly different from lateral stiffness within an individual FSU level for L5-6, L6-7, and L7-S1 but not for L4-5. When the data from 4 tested shear directions from the same specimen were pooled, level L5-6 was significantly stiffer than L7-S1. CONCLUSIONS: Increased range of motion of the lumbosacral joint is reflected by an overall decreased shear and rotational stiffness at the lumbosacral FSU. CLINICAL RELEVANCE: Data from dogs with disc degeneration have to be collected, analyzed, and compared with results from our chondrodystrophic large-breed dogs with radiographically normal spines.

Pelvic floor stimulation: what are the good vibrations?

OBJECTIVE: The aim of this study was to determine if two different whole body vibration, sinusoidal vibration (SV) and stochastic resonance vibration (SRV), using various intensities lead to a reactive activation of pelvic floor muscles. STUDY DESIGN: We compared the pelvic floor muscle response of a healthy control group with that of a post partum group with weakened pelvic floor contraction. Activation effects of stochastic resonance vibration and sinusoidal vibration with six increasing vibration intensities were investigated using pelvic floor EMG and compared to activity during rest and maximum voluntary contraction. RESULTS: Both whole body vibration systems were able to activate pelvic floor muscles significantly depending on vibration intensity. Generally, the SRV achieved a significantly higher activation than maximum voluntary contraction, especially in women post partum and using a frequency of 6-12 Hz. CONCLUSION: SRV, compared to SV, leads to higher pelvic floor muscle activation in subjects with weakened pelvic floor muscles and achieves higher pelvic floor activation than maximum voluntary contraction alone. Neurourol. Urodynam. 28:405-410, 2009. (c) 2009 Wiley-Liss, Inc.

Vibrations, Posture, and the Stabilization of Gaze: An Experimental Study on Impedance Control

Vibrations, Posture, and the Stabilization of Gaze: An Experimental Study on Impedance Control R. KREDEL, A. GRIMM & E.-J. HOSSNER University of Bern, Switzerland Introduction Franklin and Wolpert (2011) identify impedance control, i.e., the competence to resist changes in position, velocity or acceleration caused by environmental disturbances, as one of five computational mechanisms which allow for skilled and fluent sen-sorimotor behavior. Accordingly, impedance control is of particular interest in situa-tions in which the motor task exhibits unpredictable components as it is the case in downhill biking or downhill skiing. In an experimental study, the question is asked whether impedance control, beyond its benefits for motor control, also helps to stabi-lize gaze what, in turn, may be essential for maintaining other control mechanisms (e.g., the internal modeling of future states) in an optimal range. Method In a 3x2x4 within-subject ANOVA design, 72 participants conducted three tests on visual acuity and contrast (Landolt / Grating and Vernier) in two different postures (standing vs. squat) on a platform vibrating at four different frequencies (ZEPTOR; 0 Hz, 4 Hz, 8 Hz, 12 Hz; no random noise; constant amplitude) in a counterbalanced or-der with 1-minute breaks in-between. In addition, perceived exertion (Borg) was rated by participants after each condition. Results For Landolt and Grating, significant main effects for posture and frequency are re-vealed, representing lower acuity/contrast thresholds for standing and for higher fre-quencies in general, as well as a significant interaction (p < .05), standing for in-creasing posture differences with increasing frequencies. Overall, performance could be maintained at the 0 Hz/standing level up to a frequency of 8 Hz, if bending of the knees was allowed. The fact that this result is not only due to exertion is proved by the Borg ratings showing significant main effects only, i.e., higher exertion scores for standing and for higher frequencies, but no significant interaction (p > .40). The same pattern, although not significant, is revealed for the Vernier test. Discussion Apparently, postures improving impedance control not only turn out to help to resist disturbances but also assist in stabilizing gaze in spite of these perturbations. Con-sequently, studying the interaction of these control mechanisms in complex unpre-dictable environments seems to be a fruitful field of research for the future. References Franklin, D. W., & Wolpert, D. M. (2011). Computational mechanisms of sensorimotor control. Neuron, 72, 425-442.

Mechano-Biologie von bovinen Bandscheiben belastet unter Kompression und Torsion

Einleitung: Bandscheiben wirken als Schockabsorbierer in der Wirbelsäule und auf diese wirken meistens komplexe Kräfte, zusammengesetzt aus Kompression, Torsion und Flexion. Die biomechanishe Umgebung einer Bandscheibe ist denn auch geprägt von komplexen Belastungen. Die Forschung über die in vitro Bandscheibenbiologie hat sich bisher um die axiale Kompression konzentriert, wobei die Bedeutung von Torsion und insbesondere dem Zusammenspiel von Kompression und Torsion (="Twisting") praktisch noch nie untersucht wurde an lebenden Organkultur-Explantaten. Wir präsentieren neue mechanobiologische Daten über die Überlebenswahrscheinlichkeit von Bandscheibenzellen kultiviert in einem neuartigen, kompakten Design eines bi-axialen Bioreaktors, um die Bedeutung von Kompression und Torsion zu verstehen. Material/Methode: Bovine Schwanzbandscheiben mit den Endplatten wurden isoliert wie bereits beschrieben [2] und mechanische Belastung wurde angewendet mit einem 2 DoF Bioreaktor für 14 Tage [3]. Die Bandscheiben wurden in verschiedene Belastungsgruppen eingeteilt: 1) Keine Belastung (NL), 2) zyklische Kompression (CC) [8h: axiale Kompression mit 0.6 ± 0.2 MPa, 0.2 Hz], 3) zyklische Torsion (CT) [8h: ± 2° torsion, 0.2 Hz, 0.2 MPa compression], 4) zyklische Kompression und Torsion (CCT) [8h: 0.6 ± 0.2 MPa, 0.2 Hz & ± 2° torsion, 0.2 Hz]. Das Bandscheibengewebe wurde mit LIVE/DEAD gefärbt und miteinem konfokalen Mikroskop visualisiert um die Überlebensrate zu bestimmen. Zell Apoptosis wurde quantifiziert mit einem Caspase 3/7 Kit normalisiert zum totalen Proteingehalt (Bradford). Relative Gen-Expression von wichtigen Genen für die Bandscheibe wurde bestimmt von anabolischen, katabolischen und inflammatorischen Genen mittels real-time RT-PCR. Die Morphologie der Bandscheibenzellen wurde mittels Histologie bestimmt. Ergebnisse: Die Resultate zeigten einen starken Abfall der Zellüberlebenswahrscheinlichkeit im Zentrum der Bandscheiben, dem Nulceus Pulposus (NP), i.e. 10%, in der Gruppe mit CCT. Hingegen die Überlebenswahrscheinlichkeit im Annulus fibrosus (AF) war stabilisiert bei über 60% im NP und im AF in allen anderen Gruppen (Fig 1). Apoptotische Aktivität war statistisch signifikant erhöht in der CC-Gruppe, aber nicht in der CCT-Gruppe, was die Vermutung nahe legt, dass der erhöhte Zellverlust im NP nicht mit Apoptose sondern mit Nekrose erklärt werden kann. Die Gen Expression der anabolischen Gene COL1, COL2 und Biglycan war signifikant erhöht im AF in der CCT Gruppe, ebenfalls waren Remodeling-Gene angeschaltet wie ADAMTS4 und MMP-13 in der CCT Gruppe (Fig. 2). Der Glykosaminoglykan (GAG) Gehalt war generell im AF erhöht in den Gruppen unter mechanischer Belastung, jedoch nicht statistisch signifikant. Schlussfolgerung: Zyklische Torsion kombiniert mit zyklischer Kompression waren in dieser Studie erfolgreich und nach unserem besten Wissen zum ersten Mal an Bandscheibenexplantaten in einer 14- tägigen Organkultur angewendet worden in einem dafür speziell konzipierten Bioreaktor. Die Resultezeigten überraschend einen negativen Effekt bei physiologischen Parametern, was die Belastung (0.6MPa ± 0.2MPa) und die Torsion (± 2°) angeht. Dieser negative Effekt des "Twistings" auf die Überlebenswahrscheinlichkeit der Zellen war jedoch nur regional im NP von Bedeutung, wohingegen im AF keine Effekte zu detektieren waren.

Region Specific Response of Intervertebral Disc Cells to Complex Dynamic Loading: An Organ Culture Study Using a Dynamic Torsion-Compression Bioreactor

The spine is routinely subjected to repetitive complex loading consisting of axial compression, torsion, flexion and extension. Mechanical loading is one of the important causes of spinal diseases, including disc herniation and disc degeneration. It is known that static and dynamic compression can lead to progressive disc degeneration, but little is known about the mechanobiology of the disc subjected to combined dynamic compression and torsion. Therefore, the purpose of this study was to compare the mechanobiology of the intervertebral disc when subjected to combined dynamic compression and axial torsion or pure dynamic compression or axial torsion using organ culture. We applied four different loading modalities 1. control: no loading (NL), 2. cyclic compression (CC), 3. cyclic torsion (CT), and 4. combined cyclic compression and torsion (CCT) on bovine caudal disc explants using our custom made dynamic loading bioreactor for disc organ culture. Loads were applied for 8 h/day and continued for 14 days, all at a physiological magnitude and frequency. Our results provided strong evidence that complex loading induced a stronger degree of disc degeneration compared to one degree of freedom loading. In the CCT group, less than 10\% nucleus pulposus (NP) cells survived the 14 days of loading, while cell viabilities were maintained above 70\% in the NP of all the other three groups and in the annulus fibrosus (AF) of all the groups. Gene expression analysis revealed a strong up-regulation in matrix genes and matrix remodeling genes in the AF of the CCT group. Cell apoptotic activity and glycosaminoglycan content were also quantified but there were no statistically significant differences found. Cell morphology in the NP of the CCT was changed, as shown by histological evaluation. Our results stress the importance of complex loading on the initiation and progression of disc degeneration.

Left ventricular torsion abnormalities in septic shock and corrective effect of volume loading: a pilot study

BACKGROUND Ventricular torsion is an important component of cardiac function. The effect of septic shock on left ventricular torsion is not known. Because torsion is influenced by changes in preload, we compared the effect of fluid loading on left ventricular torsion in septic shock with the response in matched healthy control subjects. METHODS We assessed left ventricular torsion parameters using transthoracic echocardiography in 11 patients during early septic shock and in 11 age- and sex-matched healthy volunteers before and after rapid volume loading with 250 mL of a Ringer's lactate solution. RESULTS Peak torsion and peak apical rotation were reduced in septic shock (10.2 ± 5.2° and 5.6 ± 5.4°) compared with healthy volunteers (16.3 ± 4.5° and 9.6 ± 1.5°; P = 0.009 and P = 0.006 respectively). Basal rotation was delayed and diastolic untwisting velocity reached its maximum later during diastole in septic shock patients than in healthy volunteers (104 ± 16% vs 111 ± 14% and 13 ± 5% vs 21 ± 10%; P = 0.03 and P = 0.034, respectively). Fluid challenge increased peak torsion in both groups (septic shock, 10.2 ± 5.3° vs 12.6 ± 3.9°; healthy volunteers, 16.3 ± 4.5° vs 18.1 ± 6°; P = 0.01). Fluid challenge increased left ventricular stroke volume in septic shock patients (P = 0.003). CONCLUSIONS Compared with healthy volunteers, left ventricular torsion is impaired in septic shock patients. Fluid loading attenuates torsion abnormalities in parallel with increasing stroke volume. Reduced torsional motion might constitute a relevant component of septic cardiomyopathy, a notion that merits further testing in larger populations.

Low-lying excited states and nonradiative processes of 9-methyl-2-aminopurine

he UV spectrum of the adenine analogue 9-methyl-2-aminopurine (9M-2AP) is investigated with one- and two-color resonant two-photon ionization spectroscopy at 0.3 and 0.05 cm−1 resolution in a supersonic jet. The electronic origin at 32 252 cm−1 exhibits methyl torsional subbands that originate from the 0A′′1 (l = 0) and 1E ″ (l = ±1) torsional levels. These and further torsional bands that appear up to 000+230 cm−1 allow to fit the threefold (V 3) barriers of the torsional potentials as ∣∣V′′3∣∣=50 cm−1 in the S 0 and ∣∣V′3∣∣=126 cm−1 in the S 1 state. Using the B3LYP density functional and correlated approximate second-order coupled cluster CC2 methods, the methyl orientation is calculated to be symmetric relative to the 2AP plane in both states, with barriers of V′′3=20 cm−1 and V′3=115 cm−1. The 000 rotational band contour is 75% in-plane (a/b) polarized, characteristic for a dominantly long-axis 1ππ* excitation. The residual 25% c-axis polarization may indicate coupling of the 1ππ* to the close-lying 1 nπ* state, calculated at 4.00 and 4.01 eV with the CC2 method. However, the CC2 calculated 1 nπ oscillator strength is only 6% of that of the 1ππ* transition. The 1ππ* vibronic spectrum is very complex, showing about 40 bands within the lowest 500 cm−1. The methyl torsion and the low-frequency out-of-plane ν′1 and ν′2 vibrations are strongly coupled in the 1ππ* state. This gives rise to many torsion-vibration combination bands built on out-of-plane fundamentals, which are without precedence in the 1ππ* spectrum of 9H-2-aminopurine [S. Lobsiger, R. K. Sinha, M. Trachsel, and S. Leutwyler, J. Chem. Phys.134, 114307 (2011)]. From the Lorentzian broadening needed to fit the 000 contour of 9M-2AP, the 1ππ* lifetime is τ ⩾ 120 ps, reflecting a rapid nonradiative transition.