Alterations of directional connectivity among resting-state networks in Alzheimer disease

BACKGROUND AND PURPOSE

AD has been documented as a kind of disconnection syndrome by functional neuroimaging studies. The primary focus of this study was to examine, with the use of resting-state fMRI, whether AD would impact connectivity among RSNs.

MATERIALS AND METHODS

Fourteen patients with AD and 16 NC were recruited and scanned by using resting-state fMRI. Group independent-component analysis and the BN learning approach were used, respectively, to separate the RSNs and construct the network-to-network connectivity patterns for each group. The convergence index for the special network DMN was measured.

RESULTS

Three of the 4 connections were significantly lower in AD compared with NC. Although numerically the AD group had more connections, none was statistically different from that in the NC group except for 1 increased connection from the DMN to the DAN. The convergence index for the DMN node was lower in AD than in NC.

CONCLUSIONS

Connections among cognitive networks in AD were more vulnerable to impairment than sensory networks. The DMN decreased its integration function for other RSNs but may also play a role in compensating for the disrupted connections in AD.

Regulation of Olig2 during astroglial differentiation in the subventricular zone of a cuprizone-induced demyelination mouse model

The mammalian subventricular zone (SVZ) is the largest germinative zone of the adult brain. Progenitor cells generated from the SVZ play important roles during the remyelination process. To determine the functional role of Olig2 in regulating astroglial differentiation in the mouse SVZ, we used the cuprizone mouse model to investigate demyelination. We found that cuprizone administration significantly enhanced the expression of Olig2 and increased astroglial differentiation in the SVZ, as compared with control. Moreover, cytoplasmic translocation of Olig2 occurred after demyelination. In vitro studies further revealed that supplementation of culture media with growth factors enhanced the oligodendroglial differentiation of oligodendrocyte progenitor cells (OPCs), whereas serum alone promoted astroglial differentiation and cytoplasmic translocation of Olig2. Additionally, the expression levels of bone morphogenetic proteins 2 and 4 (BMP2 and BMP4) and inhibitor of DNA binding 2 and 4 (Id2 and Id4) were greatly elevated during astroglial differentiation. BMP inhibition by noggin suppressed the astroglial differentiation of OPCs. Our results indicate that Olig2 may serve as a key regulator during the directional differentiation of progenitor cells after demyelination. The BMP signaling pathway may contribute to the cytoplasmic translocation and altered expression of Olig2 during the remyelination process. These findings provide a better understanding of the mechanisms involved in remyelination.

WE-C-217BCD-05: A Novel Interpolation Method for the 3D Reconstruction of Cell Structures

PURPOSE

To develop a new interpolation method for accurate 3D reconstruction of cell morphology from laser scanning confocal microscope (LSCM) image data.

METHODS

Current techniques are based on the assumption that pixel intensity or contour shapes of images change linearly in the interpolation direction. Gray-value and position of the pixel in interpolated image slice are obtained through weighted average calculation with gray-values and distances of corresponding pixels in two adjacent original image slices, only information from adjacent image slices is considered, often fail to meet the need of 3D reconstruction for cells because of the complex cell morphology. The new method interpolates cellular organelle contours in polar coordinate system. Coordinate system origin is chosen to be the mass center weighted by pixel intensity instead of conventional geometric center, contour points of the organelle is sampled by their angles first and fitted with uniform cubic B-spline to perform interpolation. For complex organelle structures such as branched nuclei, a special method combining morphological information and corner detection technique based on curvature scale space has been developed to solve the contour division and related problems. New method was applied to confocal images of 130 different cells acquired with an LSCM system (LSM510, Zeiss), sampling step was set as 0.5 μm in longitudinal direction, pixel size in horizontal plane was 0.07 μm and the resolution was 512×512. Marching cubes algorithm was used for 3D reconstruction.

RESULTS

Experiments showed that reconstructed 3D images with new method have much smoother and more valid organelle surfaces for both cytoplasm and nucleus than those from conventional methods.

CONCLUSIONS

The new interpolation method can significantly improve the quality of 3D reconstruction and serve as a valid and effective tool for quantitative study of 3D cell morphology in radiation biology and other areas of life science.*support by NSFC- 81171342. Supported by the National Science Foundation of China (NSFC- 81171342).

SU-D-BRA-01: Accurate Real-Time Tumor Motion Estimation from Respiratory Surrogates via Memory-Based Learning

PURPOSE

Respiratory tumor motion is a major challenge in radiation therapy. Effective beam gating or tracking approaches necessitate an accurate knowledge of the real-time tumor motion. Fluoroscopic tracking with implanted fiducial markers is invasive and exposes the patient to additional imaging dose. Respiratory surrogate signal measured by external noninvasive and non-ionizing devices provides an attractive approach, in which estimating the tumor motion from respiratory surrogates is crucial.

METHODS

We utilize a powerful memory-based learning approach to find the complex relations between tumor motion and respiratory surrogates. The learning method uses locally weighted functions to interpolate between and extrapolate from training data. Due to the local nature of the learning functions, it is inherently robust to outliers. Moreover, both training and adapting to new data is highly efficient and almost free, making it suitable for dynamically following possibly variable internal/external relations. We evaluated the method using respiratory motion data (3D tumor motion plus 1D surrogate) from six patients (three lung and three pancreas patients).

RESULTS

Given only 5-sec (roughly one breath) pretreatment training data, the method achieved an average 3D error of 0.37 mm (range: 0.10 mm - 1.06 mm) and 95th percentile error of 0.86 mm (range: 0.24 mm - 2.47 mm) on 120-sec unseen test data. These errors are well below the average peak- to-peak amplitude (-10 mm). The errors decrease monotonically with an increasing amount of training data. Compared with the best linear model, the learning approach achieved a 21% reduction in error for an average patient (range: 10% - 42%).

CONCLUSIONS

The memory-based learning technique is able to accurately capture the highly nonlinear and complex relations between tumor and surrogate motion in an efficient manner (∼1 ms per prediction). These desirable properties make it an ideal candidate for accurate and robust tumor gating/tracking using respiratory surrogates.

Ten year survival and outcomes in a prospective cohort of new onset Chinese Parkinson's disease patients

OBJECTIVE

The 10 year outcomes and impact of motor and non-motor features on survival of a cohort of new onset Chinese Parkinson's disease (PD) patients were prospectively studied.

METHOD

A cohort of new onset PD patients from 1995 to 2002 was recruited from a regional hospital based movement disorder clinic. Subjects were classified into postural instability gait disorder (PIGD), tremor predominant type or mixed subtypes at presentation. All were evaluated yearly for development of sensory complaints, first significant fall, hallucinations, dementia, postural hypotension, speech disturbances, dysphagia and postural instability persisted during 'on' medication state (PIPon). Mortality and predictors of death were determined.

RESULTS

171 new onset PD patients were recruited. After a mean follow-up of 11.3±2.6 years, 50 (29%) patients died. The standardised mortality ratio was 1.1 (CI 0.8 to 1.5, p=0.34). 83 (49%) developed dementia, 81 (47%) had psychosis and 103 (60%) had sensory complaints. Postural hypotension was found in 58 (34%) patients, 108 (63%) had PIPon, 101 (59%) had falls, 102 (60%) had dysphagia, 148 (87%) had freezing of gait and 117 (68%) had speech disturbances. 46 (27%) were institutionalised whereas 54 (32%) lived independently. Dementia (HR 5.0, 95% CI 2.1 to 13.0), PIPon (HR 2.8, 95% CI 1.2 to 6.8), older onset (HR 1.05, 1 year increase in age, 95% CI 1.0 to 1.1) and PIGD type (HR 2.1, 95% CI 1.2 to 3.7) were independent predictors of death.

CONCLUSIONS

10 years into PD, a significant proportion of patients developed dopa resistant motor and non-motor features. Older onset, PIGD type, PIPon and dementia had a negative impact on survival. Standardised mortality ratio was 1.1.

TU-E-BRA-03: Real-Time Fiducial Detection and Prostate Movement Assessment with Cine MV Images in RapidArc Treatments

PURPOSE

To develop an algorithm for detection of metallic fiducial markers in cine MV images, and to assess the prostate movement during RapidArc treatment.

METHODS

A Varian TrueBeam linear accelerator (LINAC) was used to deliver RapidArc treatment for prostate patients. Cine images were acquired with the onboard electronic portal imaging device (EPID) using the MV therapeutic beam. Three metallic fiducial markers were implanted inside the prostate. To detect the fiducial position, we explicitly account for the possible marker blockage by MLC during beam modulation. If the marker is not blocked, we employ the planning coordinates of the marker centroids projected onto the cine MV images and perform template matching in the vicinity of its projection to localize the actual position of the marker. Displacements of the fiducial markers are assessed by comparing the actual and planned positions.

RESULTS

We analyzed ∼280 cine MV images acquired during a 55-sec RapidArc treatment for a prostate patient. The three markers were visible in about 46%, 52%, and 48% of the images, and at least one fiducial was visible during almost entire treatment (97% of the time). The marker detection algorithm agrees well with manual detection (< 0.2 mm). The mean displacement for each fiducial was 0.40 ± 0.42, 0.27 ± 0.29, and 0.46 ± 0.34 mm. The maximum displacement was 2.33, 1.75, and 2.23 mm.

CONCLUSIONS

An algorithm for automatic detection of fiducial markers in cine MV images has been developed. The prostate movement during a RapidArc treatment has been analyzed for a patient with implanted markers. Accurate target positioning is achieved at all times during treatment. In light of the random nature of intrafraction prostate motion, this work represents an important step toward real-time image-guided prostate radiation therapy.

The radiation dose-regulated AND gate genetic circuit, a novel targeted and real-time monitoring strategy for cancer gene therapy

The AND gate functions such that when all inputs are activated the downstream gene will be transcribed and it is off otherwise. To accomplish optimal and targeted gene therapy in solid tumor patients, we have constructed an AND gate genetic circuit and investigated whether it could be activated by low-dose radiation in vitro and in vivo. The enhancement green fluorescent protein (EGFP) expression in different tumor cells transfected with control vector plxsn-EGFP confirmed that 2 Gy of radiation and 1% O(2) for 3 h could activate our AND gate. Besides, the obvious different levels of EGFP expression between 2 and 6 Gy of radiation demonstrated that the AND gate could be regulated by radiation doses. Additionally, through EGFP expression and the codistribution of p53 and HIF-1α in xenografts, we illustrated the targeted activation property of the AND gate and real-time monitoring to hypoxic districts in vivo. Moreover, significant growth inhibition and cell cycle arrest in vitro and apoptosis-inducing effects in vitro and in vivo proved that the AND gate induced ideal antitumor effects. In conclusion, the radiation dose-regulated AND gate genetic circuit could not only effectively monitor the therapeutic process in real-time but also induce ideal antitumor efficacy, and can be further exploited for personal therapy in clinical tumor patients.

Micro-Raman spectroscopy study of the effect of Mid-Ultraviolet radiation on erythrocyte membrane

Mid-Ultraviolet (UVB) has a significant influence on human health. In this study, human erythrocytes were exposed to UVB to investigate the effects of UVB radiation on erythrocytes membrane. And Micro-Raman spectroscopy was employed to detect the damage. Principal component analysis (PCA) was used to classify the control erythrocytes and the irradiated erythrocytes. Results showed that the erythrocytes membrane was damaged by Mid-Ultraviolet (UVB) radiation. The intensity of the Raman peaks at 1126 cm(-1) and 1082 cm(-1) were used to calculate the Longitudinal Order-Parameters in Chains (S(trans)) which can present the liquidity and ionic permeability of erythrocyte membrane. After UVB radiation for 30 min, both the liquidity and ionic permeability decreased. At the same time, the intensity of the peaks at 1302 cm(-1) (α-helix), 1254 cm(-1) (random coil), 1452 cm(-1) and 1430 cm(-1) (CH(2)/CH(3) stretch) have also changed which indicated the membrane protein also been damaged by UVB. In the whole process of radiation, the more UVB radiation dose the more damage on the erythrocyte membrane.

Liver X receptor activation attenuates inflammatory response and protects cholinergic neurons in APP/PS1 transgenic mice

Alzheimer's disease (AD) is associated with beta-amyloid deposition, glial activation, and increased levels of the cytokines, as well as cholinergic dysfunction. Liver X receptor (LXR) has been found to inhibit the expression of pro-inflammatory genes. However, the effects of LXR activation on inflammatory response and on cholinergic system in AD are not yet clear. The present results revealed that LXR activation markedly attenuated several inflammatory markers and decreased microglial activation and reactive astrocytes in amyloid precursor protein (APP)/PS1 transgenic mice. Additionally, LXR activation significantly increased the number of cholinergic neurons in the medial septal regions and the basal nucleus of Meynert (NBM), and attenuated cognitive impairment. Furthermore, we observed that LXR activation inhibited the production of COX-2 and iNOS from Aβ(25-35)-induced microglia. LXR activation and nuclear factor kappa B (NF-κB) inhibitor PDTC both attenuated Aβ(25-35) induction of NF-κB activation. These results suggest that LXR agonists suppress the production of pro-inflammatory molecules, at least in part, by modulating NF-κB-signaling pathway. Collectively, these studies suggest that LXR agonists may have therapeutic significance in AD.

Mesenteric vein thrombosis treated successfully with ultrasound augmented thrombolysis

Mesenteric vein thrombosis is a potentially fatal condition that is associated with better outcomes with early diagnosis and intervention. A 32-year-old-man with Down syndrome presented with abdominal pain and was found to have extensive porto-splenomesenteric thrombosis with early bowel ischemia on computed tomography. He was treated successfully with ultrasound augmented thrombolysis. Ultrasound can improve efficiency of thrombolysis, decreasing the time required for thrombolysis by half, decrease thrombolytic dose and monitoring time and thus reduce overall costs and complications seen with long thrombolysis times.

Pharmacokinetic and bioequivalence studies of trospium chloride after a single-dose administration in healthy Chinese volunteers

The study aimed to compare and evaluate the bioequivalence of a new generic preparation of trospium chloride (CAS NO:10405-02-4) capsule (20 mg, test) and the available import tablet (20 mg , reference) for the requirement of state regulatory criteria in China. A randomized- sequence, 2-period crossover study was conducted in 20 healthy Chinese male volunteers in the fasted state. Blood samples were collected before and 1, 2, 3, 4, 5, 6, 7, 8, 12, 24, 36, 48, 60 h after administration of a single oral dose of 40 mg trospium chloride capsules or tablets, followed by a 7-day washout period. The concentration of trospium chloride was determined by a LC-MS/MS method. Drug And Statistical-Version 2.0 was used to calculate the pharmacokinetics parameters and assess bioequivalence of the two preparations. It was considered bioequivalent if the 90% CIs of the mean ratios (test: reference) for Cmax, AUC0-t and AUC0-∞ were within the range from 80% to 125%, respectively. The main pharmacokinetics parameters of test and reference were as follows: t1/2 was (15.11 ± 3.24) h and (16.00 ± 3.96) h; Tmax was (4.0 ± 1.2) h and (4.1 ± 0.9) h; Cmax was (3.76 ± 1.87) ng·mL - 1 and (3.70 ± 1.89) ng·mL - 1; AUC0-t was (33.51 ± 14.39) ng·mL - 1·h and (33.33 ± 14.88) ng·mL - 1·h, and the AUC0-∞ was (35.20 ± 14.88) ng·mL - 1·h and (35.16±15.17) ng·mL - 1·h. The ratios (test: reference) for Cmax, AUC0-t, and AUC0-∞ were 94.0%~111.7%, 96.4%~106.8%, and 96.1%~105.3%, respectively. No significant differences in pharmacokinetic parameters were found between preparations and periods (p>0.05). No obvious adverse events were monitored throughout the study based on clinical parameters and patient reports.

Bioequivalence of two misoprostol tablets in healthy Chinese female volunteers: a single-dose, two-period, double crossover study

OBJECTIVE

To assess the bioequivalence of a new generic formulation of misoprostol (CAS 59122-46-2) 0.2 mg tablets (test) and the available branded tablet (reference) for the requirement of state regulatory criteria and the marketing of the test product in China.

METHODS

A randomized-sequence, 2-period crossover study was conducted in 20 healthy Chinese female volunteers in the fasted state. Blood samples were collected at baseline and 0.083, 0.17, 0.25, 0.33, 0.5, 0.75, 1, 1.25, 1.5, 2, 3, 4 and 6 h after a single oral dose of 0.6 mg misoprostol test or reference, followed by a 7-day washout period. Misoprostol acid, the active metabolite of misoprostol, was determined by an HPLC-MS/MS method. Drug And Statistics 2.0 was used to calculate the pharmacokinetics parameters and assess bioequivalence of the 2 formulations. It was considered bioequivalent if the 90% CIs of the mean ratios (test: reference) for Tmax, Cmax and AUC0-t were all within the range from 80% to 125%. Adverse events were monitored throughout the study based on clinical parameters and patient reports.

RESULTS

The main pharmacokinetics parameters for the test and reference were as follows: t1/2 was (0.680 ± 0.371) h and (0.650 ± 0.264) h; Tmax was (0.415 ± 0.087) h and (0.399 ± 0.097) h; Cmax was (1.941 ± 0.417) ng/mL and (2.047 ± 0.397) ng/mL; AUC0-t was (1.535 ± 0.419) ng·h/mL and (1.652 ± 0.400)ng·h/mL, and the AUC0-∞ was (1.576 ± 0.465) ng·h/mL and (1.686 ± 0.396) ng·h/mL. The mean ratios (test: reference) for Cmax, AUC0-t, and AUC0-∞ were 95.3% ±13.2%, 92.65% ± 17.31%, and 93.61%±18.97%, respectively. No significant (p>0.05) differences in pharmacokinetic parameters were found between preparations, treatments and periods.

CONCLUSIONS

This single-dose study in healthy Chinese fasted volunteers was shown that the misoprostol test and reference met the requirement of US and China regulatory criterion, and the test and reference were bioequivalent.