Rotational Intensity Research Articles

Adaptive multi-level conditional random fields for detection and segmentation of small enhanced pathology in medical images.

Detection and segmentation of large structures in an image or within a region of interest have received great attention in the medical image processing domains. However, the problem of small pathology detection and segmentation still remains an unresolved challenge due to the small size of these pathologies, their low contrast and variable position, shape and texture. In many contexts, early detection of these pathologies is critical in diagnosis and assessing the outcome of treatment. In this paper, we propose a probabilistic Adaptive Multi-level Conditional Random Fields (AMCRF) with the incorporation of higher order cliques for detecting and segmenting such pathologies. In the first level of our graphical model, a voxel-based CRF is used to identify candidate lesions. In the second level, in order to further remove falsely detected regions, a new CRF is developed that incorporates higher order textural features, which are invariant to rotation and local intensity distortions. At this level, higher order textures are considered together with the voxel-wise cliques to refine boundaries and is therefore adaptive. The proposed algorithm is tested in the context of detecting enhancing Multiple Sclerosis (MS) lesions in brain MRI, where the problem is further complicated as many of the enhancing voxels are associated with normal structures (i.e. blood vessels) or noise in the MRI. The algorithm is trained and tested on large multi-center clinical trials from Relapsing-Remitting MS patients. The effect of several different parameter learning and inference techniques is further investigated. When tested on 120 cases, the proposed method reaches a lesion detection rate of 90%, with very few false positive lesion counts on average, ranging from 0.17 for very small (3-5 voxels) to 0 for very large (50+ voxels) regions. The proposed model is further tested on a very large clinical trial containing 2770 scans where a high sensitivity of 91% with an average false positive count of 0.5 is achieved. Incorporation of contextual information at different scales is also explored. Finally, superior performance is shown upon comparing with Support Vector Machine (SVM), Random Forest and variant of an MRF.

Influence of an external force field on the dynamics of a free core and fluid in a rotating spherical cavity

This research involves experimental studies of the dynamics of a free spherical core and fluid motion in a spherical cavity rotating around the horizontal axis. The gravity field causes circular oscillations of the core in the reference frame of the cavity creating an averaged force in the Stokes boundary layer which makes the core rotate relative to the cavity (vibrational hydrodynamic top). The core rotates in the direction opposite to that of the cavity (lagging differential rotation). The research shows that the differential rotation intensity is determined by the ratio between the gravitational and centrifugal acceleration, as well as the ratio of the core size to the thickness of the Stokes layer. Various regimes of the fluid flow have been studied. The shape of subcritical flow is a circular-section column extended along the geometric continuation of the sphere. Increasing the differential rotation rate of the core results in various independent modes of instability of the column. One of such modes involves development of an azimuthal wave on the column boundary. The second mode is a system of two-dimensional vortices extended along the axis and rotating inside the column. It has been discovered that the development of supercritical structures causes changes in the differential rotation rate of the core.

SU‐E‐T‐483: In Vivo Dosimetry of Conventional and Rotational Intensity Modulated Radiotherapy Using Integral Quality Monitor (IQM)

Purpose:To investigate the accuracy, sensitivity and constancy of integral quality monitor (IQM), a new system for in vivo dosimetry of conventional intensity modulated radiation therapy (IMRT) or rotational volumetric modulated arc therapy (VMAT)Methods:A beta‐version IQM system was commissioned on an Elekta Infinity LINAC equipped with 160‐MLCs Agility head. The stationary and rotational dosimetric constancy of IQM was evaluated, using five‐field IMRT and single‐or double‐arc VMAT plans for prostate and head‐and‐neck (H&N) patients. The plans were delivered three times over three days to assess the constancy of IQM response. Picket fence (PF) fields were used to evaluate the sensitivity of detecting MLC leaf errors. A single leaf offset was intentionally introduced during delivery of various PF fields with segment apertures of 3×1, 5×1, 10×1, and 24×1cm2. Both 2mm and 5mm decrease in the field width were used.Results:Repeated IQM measurements of prostate and H&N IMRT deliveries showed 0.4 and 0.5% average standard deviation (SD) for segment‐by‐segment comparison and 0.1 and 0.2% for cumulative comparison. The corresponding SDs for VMAT deliveries were 6.5, 9.4% and 0.7, 1.3%, respectively. Statistical analysis indicates that the dosimetric differences detected by IQM were significant (p < 0.05) in all PF test deliveries. The largest average IQM signal response of a 2 mm leaf error was found to be 2.1% and 5.1% by a 5mm leaf error for 3×1 cm2 field size. The same error in 24×1 cm2 generates a 0.7% and 1.4% difference in the signal.Conclusion:IQM provides an effective means for real‐time dosimetric verification of IMRT/ VMAT treatment delivery. For VMAT delivery, the cumulative dosimetry of IQM needs to be used in clinical practice.

Local image descriptor based on spectral embedding

This study presents a local image descriptor based on spectral embedding. Specifically, the spectra of line graph are used to represent image edges, corners and edge points with big curvature. The authors theoretically analyse and experimentally verify that the spectra of line graph are robust to noise and are invariant to rotation and linear intensity changes. Based on such a fact, some local image descriptors are constructed using the spectra of line graph. Comparative experiments demonstrate the effectiveness of the proposed descriptor and its superiority to some state‐of‐the‐art descriptors under image rotation, image blur, viewpoint change, illumination change, JPEG compression and noise.

PO-0677: Rotational intensity Modulated Radiation Therapy in complex adjuvant breast and nodes irradiation

pZ.028), receive chemotherapy (84% vs. 67%, p<.001), and receive Herceptin (39% vs. 23%, pZ.005). The 7-year LRR-free survival for the entire cohort was 92.4% (95% CI 88.7-94.9). EIC+ patients had a significantly higher 7-year LRR rate (14.7% vs. 5.2%, pZ.019), as did younger (age 50) patients (14.1% vs. 3.7%, p<.001). After adjustment for age, chemotherapy receipt, and Herceptin receipt, the presence of EIC remained significant for increased LRR (HR 2.34; 95% CI 1.08-5.06; pZ.031). Conclusion: EIC was a prominent pathologic feature seen in 24% of patients with HER2+ breast cancer treated with breast conserving therapy. Despite the achievement of negative surgical margins in the vast majority of patients, EIC was prognostic for LRR. These results must be confirmed in larger cohorts of HER2+ patients treated with anti-HER2 therapies. Author Disclosure: N. Ohri: None. C.T. Siu: None. A. Eaton: None. A.Y. Ho: None.

Hybrid variational–perturbation method for calculating ro-vibrational energy levels of polyatomic molecules

A procedure for calculation of rotational–vibrational states of medium-sized molecules is presented. It combines the advantages of variational calculations and perturbation theory. The vibrational problem is solved by diagonalising a Hamiltonian matrix, which is partitioned into two sub-blocks. The first, smaller sub-block includes matrix elements with the largest contribution to the energy levels targeted in the calculations. The second, larger sub-block comprises those basis states which have little effect on these energy levels. Numerical perturbation theory, implemented as a Jacobi rotation, is used to compute the contributions from the matrix elements of the second sub-block. Only the first sub-block needs to be stored in memory and diagonalised. Calculations of the vibrational–rotational energy levels also employ a partitioning of the Hamiltonian matrix into sub-blocks, each of which corresponds either to a single vibrational state or a set of resonating vibrational states, with all associated rotational levels. Physically, this partitioning is efficient when the Coriolis coupling between different vibrational states is small. Numerical perturbation theory is used to include the cross-contributions from different vibrational states. Separate individual sub-blocks are then diagonalised, replacing the diagonalisation of a large Hamiltonian matrix with a number of small matrix diagonalisations. Numerical examples show that the proposed hybrid variational–perturbation method greatly speeds up the variational procedure without significant loss of precision for both vibrational–rotational energy levels and transition intensities. The hybrid scheme can be used for accurate nuclear motion calculations on molecules with up to 15 atoms on currently available computers.

Electronic spectrum of the UO and UO(+) molecules.

Electronic theory calculations are applied to the study of the UO molecule and the UO(+) ion. Relativistic effective core potentials are used along with the accompanying valence spin-orbit operators. Polarized double-ς and triple-ς basis sets are used. Molecular orbitals are obtained from state-averaged multiconfiguration self-consistent field calculations and then used in multireference spin-orbit configuration interaction calculations with a number of millions of terms. The ground state of UO has open shells of 5f(3)7s(1), angular momentum Ω = 4, and a spin-orbit-induced avoided crossing near the equilibrium internuclear distance. Many UO excited states are studied with rotational constants, intensities, and experimental comparisons. The ground state of UO(+) is of 5f(3) nature with Ω = 9/2. Many UO(+) excited states are also studied. The open-shell nature of both UO and UO(+) leads to many low-lying excited states.

Effects of Right Ventricular Hemodynamic Burden on Intraventricular Flow in Tetralogy of Fallot: An Echocardiographic Contrast Particle Imaging Velocimetry Study

The purpose of this investigation was to test the hypothesis that flow patterns in the right ventricle are abnormal in patients with repaired tetralogy of Fallot (TOF). High-resolution echocardiographic contrast particle imaging velocimetry was used to investigate rotation intensity and kinetic energy dissipation of right ventricular (RV) flow in patients with TOF compared with normal controls. Forty-one subjects (16 with repaired TOF and varying degrees of RV dilation and 25 normal controls) underwent prospective contrast imaging using the lipid-encapsulated microbubble (Definity) on Sequoia systems. A mechanical index of 0.4, three-beat high-frame rate (>60Hz) captures, and harmonic frequencies were used. Rotation intensity and kinetic energy dissipation of flow in the right and left ventricles were studied (Hyperflow). Ventricular volumes and ejection fractions in all subjects were derived from same-day cardiac magnetic resonance (CMR). Measurable planar maps were obtained for the left ventricle in 14 patients and the right ventricle in 10 patients among those with TOF and for the left ventricle in 23 controls and the right ventricle in 21 controls. Compared with controls, the TOF group had higher RV indexed end-diastolic volumes (117.8±25.5 vs 88±15.4mL/m(2), P<.001) and lower RV ejection fractions (44.6 ± 3.6% vs 51.8±3.6%, P<.001). Steady-streaming (heartbeat-averaged) flow rotation intensities were higher in patients with TOF for the left ventricle (0.4±0.13 vs 0.29±0.08, P=.012) and the right ventricle (0.53±0.15 vs 0.26±0.12, P<.001), whereas kinetic energy dissipation in TOF ventricles was lower (for the left ventricle, 0.51±0.29 vs 1.52±0.69, P<.001; for the right ventricle, 0.4±0.24 vs 1.65±0.91, P<.001). It is feasible to characterize RV and left ventricular flow parameters and planar maps in adolescents and adults with repaired TOF using echocardiographic contrast particle imaging velocimetry. Intraventricular flow patterns in the abnormal and/or enlarged right ventricle in patients with TOF differ from those in normal young adults. The rotation intensity and energy dissipation trends in this investigation suggest that they may be quantitative markers of RV and left ventricular compliance abnormalities in patients with repaired TOF. This hypothesis merits further investigation.

P09 * CAN RAPIDARC(R) IMPROVE THE OUTCOME OF GLIOMAS TREATED WITH RADIOTHERAPY?

INTRODUCTION:Radiotherapy is used to treat high and low grade gliomas either as primary therapy or as an adjunct following surgery. However, long term side effects in patients with low grade gliomas, and complete tumour coverage in high grade gliomas is a concern due to the proximity of sensitive structures in the central nervous system. RapidArc® Volumetric arc therapy is a type of rotational intensity modulated radiotherapy (IMRT) used to reduce dose to organs at risk (OARs) and improve dose and coverage of the target. Could this improve outcomes and toxicity in gliomas treated with radiotherapy? We will discuss the experience of using RapidArc® in our centre for the treatment of gliomas over a 2 year period. METHOD:We compared radiotherapy treatment plans for gliomas before and after the establishment of RapidArc® planning. Treatment volumes, beam arrangements with colourwashes and dose-volume histograms were analysed for comparison. RESULTS: Planning with RapidArc® as compared to conventionally planned radiotherapy results in a significant reduction in the area treated to a higher dose, especially to the optic lenses and the normal surrounding brain. It does however, result in a larger area receiving a low dose of radiation.The dose distribution and homogeneity across the PTV was significantly better with RapidArc® as compared to conventionally planned radiotherapy. Tumours close to OARs (e.g. chiasm) received much better coverage with RapidArc®. CONCLUSION: RapidArc® is a modern IMRT technique that results in better coverage of the target and reduced doses to the OARs when treating gliomas. Longer term follow up ideally within a clinical trial is needed to confirm the improvements in long term outcomes and toxicity.

Static and rotational intensity modulated techniques for head-neck cancer radiotherapy: A planning comparison

PurposeTo compare helical Tomotherapy (HT), two volumetric-modulated arc techniques and conventional fixed-field intensity modulated techniques (S-IMRT) for head-neck (HN) cancers. Methods and materialsEighteen HN patients were considered. Four treatment plans were generated for each patient: HT, S-IMRT optimised with Eclipse treatment planning system and two volumetric techniques using Elekta–Oncentra approach (VMAT) and Varian-RapidArc (RA), using two full arcs. All techniques were optimised to simultaneously deliver 66Gy to PTV1 (GTV and enlarged nodes) and 54Gy to PTV2 (subclinical and electively treated nodes). Comparisons were assessed on several dosimetric parameters and, secondarily, on planned MUs and delivery time. ResultsConcerning PTV coverage, significantly better results were found for HT and RA. HT significantly improved the target coverage both compared to S-IMRT and VMAT. No significant differences were found between S-IMRT and volumetric techniques in terms of dose homogeneity. For OARs, all the techniques were able to satisfy all hard constraints; significantly better results were found for HT, especially in the intermediate dose range (15–30 Gy). S-IMRT reached a significantly better OARs sparing with respect to VMAT and RA. No significant differences were found for body mean dose, excepting higher values of V5–V10 for HT. A reduction of planned MUs and delivery treatment time was found with volumetric techniques. ConclusionsThe objectives of satisfying target coverage and sparing of critical structures were reached with all techniques. S-IMRT techniques were found more advantageous compared to RA and VMAT for OARs sparing. HT reached the best overall treatment plan quality.

A description of neck motor performance, neck pain, fatigue, and mental effort while driving in a sample with chronic whiplash-associated disorders.

Individuals with chronic whiplash-associated disorders (WADs) often note driving as a difficult task. This study's aims were to (1) compare, while driving, neck motor performance, mental effort, and fatigue in individuals with chronic WAD against healthy controls and (2) investigate the relationships of these variables and neck pain to self-reported driving difficulty in the WAD group. This study involved 14 participants in each group (WAD and control). Measures included self-reported driving difficulty and measures of neck pain intensity, overall fatigue, mental effort, and neck motor performance (head rotation and upper trapezius activity) while driving a simulator. The WAD group had greater absolute path of head rotation in a simulated city area and used greater mental effort (P = 0.04), but there were no differences in other measures while driving compared with the controls (all P ≥ 0.05). Self-reported driving difficulty correlated moderately with neck pain intensity, fatigue level, and maximum velocity of head rotation while driving in the WAD group (all P < 0.05). Individuals with chronic WAD do not seem to have impaired neck motor performance while driving yet use greater mental effort. Neck pain, fatigue, and maximum head rotation velocity could be potential contributors to self-reported driving difficulty in this group.

High-Level, First-Principles, Full-Dimensional Quantum Calculation of the Ro-vibrational Spectrum of the Simplest Criegee Intermediate (CH2OO).

The ro-vibrational spectrum of the simplest Criegee intermediate (CH2OO) has been determined quantum mechanically based on nine-dimensional potential energy and dipole surfaces for its ground electronic state. The potential energy surface is fitted to more than 50 000 high-level ab initio points with a root-mean-square error of 25 cm(-1), using a recently proposed permutation invariant polynomial neural network method. The calculated rotational constants, vibrational frequencies, and spectral intensities of CH2OO are in excellent agreement with experiment. The potential energy surface provides a valuable platform for studying highly excited vibrational and unimolecular reaction dynamics of this important molecule.

A theoretical and experimental study of pressure broadening of the oxygen A-band by helium.

The rotationally resolved magnetic dipole absorption spectrum of the oxygen A-band b(1)Σ(g)(+)(v=0) <- X(3)Σ(g)(-)(v=0) perturbed by collisions with helium was studied theoretically using the impact approximation. To calculate the relaxation matrix, scattering calculations were performed on a newly computed helium-oxygen (b(1)Σ(g)(+)) interaction potential as well as on a helium-oxygen (X(3)Σ(g)(-)) interaction potential from the literature. The calculated integrated line cross sections and broadening coefficients are in good agreement with experimental results from the literature. Additionally, cavity ring-down experiments were performed in the wings of the spectral lines for a quantitative study of line-mixing, i.e., the redistribution of rotational line intensities by helium-oxygen collisions. It is shown that inclusion of line-mixing in the theory is required to reproduce the experimentally determined absolute absorption strengths as a function of the density of the helium gas.

An enhanced method for using the IPCC approach to estimate soil organic carbon storage potential on U.S. agricultural soils

The Intergovernmental Panel on Climate Change (IPCC) provides a method to estimate soil organic carbon (SOC) stock changes relative to the SOC stock under native vegetation. This manuscript modifies the IPCC approach to use the ending SOC stock from the previous inventory as the SOC stock that is changed by land use and management activities during the next inventory and to track the crop rotation and tillage intensity through three inventories. The approach allows annual rates of change of carbon sequestration from different historic land uses and management to be estimated explicitly for each assessment point based on the effect of previous land use and management. The model generates 3524 unique annual SOC sequestration rates that vary by land use and management history on U.S. agricultural land based on the 30 SOC stock reference values provided by IPCC documentation. An average of 0.33MgCha−1yr−1 is stored when cropland that was conventionally tilled in two previous inventories is set-aside in the third inventory, but only 0.14MgCha−1yr−1 when it is conventionally tilled in the first inventory and no-till in the second inventory before it is set aside. Incorporating a winter cover on cropland that was conventionally tilled in the first inventory and no-till in the second and third inventories is estimated to store 0.49MgCha−1yr−1, but could store 0.81MgCha−1yr−1 if it was conventionally tilled in the first two inventories and under no-till in the final inventory. Cropland under conventional tillage in the first two inventories and no-till the final inventory could store an average of 0.34MgCha−1yr−1, but cropland under conventional tillage in the first, reduced tillage in the second, and no-till in the third inventory is estimated to store 0.19MgCha−1yr−1. The detailed annual rates of SOC stock change estimated using the approach is useful for economic or other analyses and for policymakers.

Enhanced surface dose via fine brass mesh for a complex skin cancer of the head and neck: Report of a technique

PurposeThe use of fine brass mesh in conjunction with rotational intensity modulated radiation to enhance surface dose for a complex skin cancer of the head and neck has not previously been described. Methods and materialsWe present a case of locally advanced basal cell carcinoma with temporal bone erosion treated with rotational intensity modulated radiation via helical tomotherapy with brass mesh. In vivo surface dose was assessed at multiple locations to verify delivered surface dose. Phantom measurements identified the enhancement ratio with the addition of brass mesh, and evaluated impact on the underlying dose distribution. ResultsThe brass mesh use was feasible and conformed well to the underlying surface. In vivo dosimetry identified excellent skin surface dose with a mean of 103% of the prescription dose at the surface (range, 97%-120%). Phantom measurements identified a surface dose enhancement ratio of 1.36, and 1.38, respectively, with placement of brass mesh. Clinically, the patient is without evidence of disease or major treatment sequelae at 12 months follow-up. ConclusionsFor complex cutaneous malignancies with irregular surfaces unsuitable for tissue equivalent bolus, brass mesh provides an alternate method of increasing surface dose if inadequate surface dosimetry is identified with phantom or in vivo measurements.

A comparison of two non-thrust mobilization techniques applied to the C7 segment in patients with restricted and painful cervical rotation

Objectives:Cervical mobilization and manipulation have been shown to improve cervical range of motion and pain. Rotatory thrust manipulation applied to the lower cervical segments is associated with controversy and the potential for eliciting adverse reactions (AR). The purpose of this clinical trial was to describe two translatory non-thrust mobilization techniques and evaluate their effect on cervical pain, motion restriction, and whether any adverse effects were reported when applied to the C7 segment.Methods:This trial included 30 participants with painful and restricted cervical rotation. Participants were randomly assigned to receive one of the two mobilization techniques. Active cervical rotation and pain intensity measurements were recorded pre- and post-intervention. Within group comparisons were determined using the Wilcoxon signed-rank test and between group comparisons were analyzed using the Mann–Whitney U test. Significance was set at P = 0·05.Results:Thirty participants were evaluated immediately after one of the two mobilization techniques was applied. There was a statistically significant difference (improvement) for active cervical rotation after application of the C7 facet distraction technique for both right (P = 0·022) and left (P = 0·022) rotation. Statistically significant improvement was also found for the C7 facet gliding technique for both right (P = 0·022) and left rotation (P = 0·020). Pain reduction was statistically significant for both right and left rotation after application of both techniques. Both mobilization techniques produced similar positive effects and one was not statistically superior to the other.Discussion:A single application of both C7 mobilization techniques improved active cervical rotation, reduced perceived pain, and did not produce any AR in 30 patients with neck pain and movement limitation. These two non-thrust techniques may offer clinicians an additional safe and effective manual intervention for patients with limited and painful cervical rotation. A more robust experimental design is recommended to further examine these and similar cervical translatory mobilization techniques.

Self-consistent flattened isochrones

We present a family of self-consistent axisymmetric stellar systems that have analytic distribution functions (DFs) of the form f(J), so they depend on three integrals of motion and have triaxial velocity ellipsoids. The models, which are generalizations of Hénon's isochrone sphere, have four dimensionless parameters, two determining the part of the DF that is even in Lz and two determining the odd part of the DF (which determines the azimuthal velocity distribution). Outside their cores, the velocity ellipsoids of all models tend to point to the model's centre, and we argue that this behaviour is generic, so near the symmetry axis of a flattened model, the long axis of the velocity ellipsoid is naturally aligned with the symmetry axis and not perpendicular to it as in many published dynamical models of well-studied galaxies. By varying one of the DF parameters, the intensity of rotation can be increased from zero up to a maximum value set by the requirement that the DF be non-negative. Since angle–action coordinates are easily computed for these models, they are ideally suited for perturbative treatments and stability analysis. They can also be used to choose initial conditions for an N-body model that starts in perfect equilibrium, and to model observations of early-type galaxies. The modelling technique introduced here is readily extended to different radial density profiles, more complex kinematics and multicomponent systems. A number of important technical issues surrounding the determination of the models’ observable properties are explained in two appendices.

COMPUTATIONAL PREDICTION OF THE SPECTROSCOPIC PARAMETERS OF METHANEDIOL, AN ELUSIVE MOLECULE FOR INTERSTELLAR DETECTION

The molecular structure of methanediol has been investigated by means of quantum chemical calculations. Two conformers, corresponding to C{sub 2} and C {sub s} symmetries, respectively, were considered. The C{sub 2} conformer is found to lie about 1.7 (at 298 K) or 2.3 (at 0 K) kcal mol{sup –1} below the C {sub s} conformer. Predictions for their rotational constants, vibrational frequencies, IR intensities, and dipole moments have been provided. The lowest-lying isomer has a very low dipole moment, around 0.03 D, whereas the C {sub s} conformer has a relatively high dipole moment, namely, 2.7 D. The barrier for the C {sub s} →C{sub 2} process is predicted to be around 0.7-1 kcal mol{sup –1}. Based on the energetic results the proportion of the C{sub s} conformer is likely to be negligible under low temperature conditions, such as in the interstellar medium. Therefore, it is predicted that detection by radioastronomy of methanediol would be rather unlikely.

Direct evidence to support the restriction of intramolecular rotation hypothesis for the mechanism of aggregation-induced emission: temperature resolved terahertz spectra of tetraphenylethene

In contrast to the traditional fluorescent dyes that exhibit a decrease in fluorescence upon aggregation, Aggregation-Induced Emission (AIE) molecules are a family of fluorophors which exhibit increased fluorescence upon aggregation. Consequently, AIE molecules represent an interesting new material with potential applications in fluorescent chemo/biosensors, light emitting devices and medical diagnostics. Numerous mechanisms have been proposed to explain this phenomenon, including E–Z isomerization, and restriction of intramolecular rotations (RIR). However, there has not been any direct experimental evidence to support either one of these hypotheses. Here we use terahertz time-domain-spectroscopy (THz-TDS) and solid-state computational simulations of an AIE molecule to link the increase in intensity of intramolecular rotation and rocking modes to the measured fluorescence and reveal direct evidence supporting the RIR hypothesis. This is the first time that terahertz spectroscopy has been used to directly probe such molecular motions in AIE materials and in doing so we have found conclusive evidence to fully explain the AIE mechanism.

Effect of Tianqi antitremor granules on behavioral manifestations and expression of G protein-coupled receptor kinase 6 and &amp;beta;-arrestin1 in levodopa-induced dyskinesia in a rat model of Parkinson&amp;#39;s disease

BackgroundRecent studies have shown that expression of G protein-coupled receptor kinase 6 (GRK6) and β-arrestin1 in the striatum is closely associated with hyperactive dopamine receptors in rats with levodopa-induced dyskinesia (LID). Our research group has shown that Tianqi antitremor granules have a significant effect on the motor complications of Parkinson’s disease (PD). However, whether Tianqi antitremor granules have an effect on the behavioral manifestations and expression of GRK6 and β-arrestin1 in rats with LID is unknown.MethodsRats with PD received twice daily intraperitoneal injections of levodopa for 4 weeks to induce dyskinesia. Rats with LID were randomly divided into five groups: an LID-control group, an LID group, a levodopa plus Tianqi antitremor granules as traditional Chinese medicine (TCM)-low group, a levodopa plus TCM-medium group, and levodopa plus TCM-high group. Peak intensity of rotations was measured. GRK6 and β-arrestin1 expression in the striatum of the dyskinetic rats was observed by immunohistochemistry and Western blotting.ResultsPulsatile treatment with levodopa induced abnormal involuntary movements in rats with PD similar to LID in patients with PD. We found that repeated levodopa administration increased peak rotations in dyskinetic rats. However, peak rotations were decreased in rats given levodopa plus the different doses of Tianqi antitremor granules. In accordance with changed behavior, GRK6 and β-arrestin1 expression was decreased in rats with PD and was persistently low in rats with LID, but this decrease was prevented by coadministration of levodopa and Tianqi antitremor granules.ConclusionTianqi antitremor granules ameliorated levodopa-induced dyskinetic behavior, reversed the decrease in GRK6 and β-arrestin1 expression, and acted as a useful adjunctive medicine for the treatment of LID.