29 POSITRON EMISSION TOMOGRAPHY IMAGING OF BRAIN METABOLISM AND DOPAMINERGIC NEURON DESTRUCTION IN PARKINSON'S DISEASE MODEL PIG

Due to similarities between human and porcine, pigs have been proposed as an excellent experimental animal for human medical research. Especially in paediatric brain research, piglets share similarities with human infants in the extent of peak brain growth at the time of birth and the growth pattern of brain. Thus, these findings have supported the wider use of pigs rather than rodents in neuroscience research. Previously, we reported the production of porcine model of Parkinson's disease (PD) by nuclear transfer using donor cell that had been stably infected with lentivirus containing the human α-synuclein gene. The purpose of this study was to determine the alternation of brain metabolism and dopaminergic neuron destruction using noninvasive method in a 2-yr-old PD model and a control pig. The positron emission tomography (PET) scan was done using Biograph TruePoint40 with a TrueV (Siemens, Munich, Germany). The [18F]N-(3-fluoropropyl)-2β-carbomethoxy-3β-(4-iodophenyl) nortropane (FP-CIT) was administrated via the ear vein. Static images of the brain for 15 min were acquired from 2 h after injection. The 18F-fluorodeoxy-D-glucose PET (18F-FDG PET) images of the brain were obtained for 15 min at 45 min post-injection. Computed tomography (CT) scan and magnetic resonance imaging (MRI) were performed at the same location of the brain. In both MRI and CT images, there was no difference in brain regions between PD model and control pigs. However, administration of [18F]FP-CIT was markedly decreased in the bilateral putamen of the PD model pig compared with the control pigs. Moreover, [18F]FP-CIT administration was asymmetrical in the PD model pig but it was symmetrical in control pigs. Regional brain metabolism was also assessed and there was no significant difference in cortical metabolism of PD model and control pigs. We demonstrated that PET imaging could provide a foundation for translational Parkinson neuroimaging in transgenic pigs. In the present study, a 2-yr-old PD model pig showed dopaminergic neuron destruction in brain regions. Therefore, PD model pig expressing human α-synuclein gene would be an efficient model for human PD patients. This study was supported by Korea IPET (#311011–05–5-SB010), Research Institute for Veterinary Science, TS Corporation and the BK21 plus program.

Combination therapy of intravitreal bevacizumab with single simultaneous posterior subtenon triamcinolone acetonide for macular edema due to branch retinal vein occlusion

PurposeTo evaluate efficacy and safety of combination therapy of intravitreal bevacizumab (IVB) with single simultaneous posterior subtenon triamcinolone acetonide (STA) for treatment of macular edema (ME) secondary to branch retinal vein occlusion (BRVO).MethodsThis was a prospective, randomized, interventional comparative study conducted in 45 eyes with ME secondary to BRVO who were treated primarily with IVB 1.25 mg (23 eyes, IVB group) or combination therapy of IVB 1.25 mg with a single simultaneous STA 40 mg (18 eyes, IVB/STA group). Reinjections were performed with IVB if optical coherence tomography (OCT) showed recurrent ME associated with decreased visual acuity. The main outcome measurement was the number of additional IVB injections, and changes of best-corrected visual acuity (BCVA) and central macular thickness (CMT) during a 6-month follow-up period were compared.ResultsBCVA showed significant improvement in two groups at 6 months. In addition, CMT showed significant decrease in two groups at 6 months. No significant differences in the change of BCVA and CMT at 6 months after injection (P=0.973, P=0.639) were observed between the two groups. A statistically significant difference was found regarding the number of additional IVB injections (IVB group 0.96±0.83; IVB/STA group 0.44±0.70, P=0.034).ConclusionAlthough combination therapy of IVB with a single simultaneous STA for treatment of ME secondary to BRVO did not affect the visual outcomes compared with IVB monotherapy, it had a benefit of reducing the number of additional IVB injections.

Clinical Applications of Simultaneous PET/MR Imaging Using (R)-[11C]-Verapamil with Cyclosporin A: Preliminary Results on a Surrogate Marker of Drug-Resistant Epilepsy

BACKGROUND AND PURPOSE

The development of resistance to antiepileptic drugs is explained well by the transporter hypothesis, which suggests that drug resistance is caused by inadequate penetration of drugs into the brain barrier as a result of increased levels of efflux transporter such as p-glycoprotein. To evaluate the brain expression of p-glycoprotein in patients with drug-resistant epilepsy, including neocortical epilepsy, we developed a noninvsive quantitative analysis including asymmetry indices based on (R)-[(11)C]-verapamil PET/MR imaging with cyclosporin A, a p-glycoprotein inhibitor.

MATERIALS AND METHODS

Six patients with drug-resistant epilepsy, 5 patients with drug-sensitive epilepsy, and 8 healthy controls underwent dynamic (R)-[(11)C]-verapamil PET/MR imaging with an intravenous infusion of cyclosporin A. Asymmetry indices [(Right Region - Left Region)/(Right Region + Left Region) × 200%] of the standard uptake values in each of the paired lobes were calculated.

RESULTS

All patients with drug-resistant epilepsy had significantly different asymmetry from the healthy controls, whereas all patients with drug-sensitive epilepsy had asymmetry similar to that in healthy controls. In the temporal lobe, the asymmetry indices of patients with left temporal lobe drug-resistant epilepsy were more positive than those of healthy controls (healthy controls: 4.0413 ± 1.7452; patients: 7.2184 ± 1.8237; P = .048), and those of patients with right temporal drug-resistant epilepsy were more negative (patients: -1.6496 ± 3.4136; P = .044). In addition, specific regions that had significant asymmetry were different between the lateral and medial temporal lobe epilepsy groups. In the frontal lobe, the asymmetry index of patients with right frontal lobe drug-resistant epilepsy was more negative than that in healthy controls.

CONCLUSIONS

We confirmed that statistical parametric mapping analysis by using asymmetry indices of (R)-[(11)C]-verapamil PET/MR imaging with cyclosporin A could be used as a surrogate marker for drug-resistant epilepsy, and this approach might be helpful for localizing or lateralizing the epileptic zone.

Variable response of cholinesterase activities following human exposure to different types of organophosphates

We investigated the red blood cell (RBC) acetylcholinesterase (AChE) activities and butyrylcholinesterase (BChE) activities at presentation to the emergency department (ED) and at 24 h after presentation following poisoning by dichlorvos, fenitrothion, or ethyl p-nitrophenol thio-benzene phosphonate (EPN). Although the patients from different groups had similar characteristics at presentation such as time interval from ingestion to presentation to the ED and the amount of organophosphate ingested, the dichlorvos group had significantly lower BChE levels than the fenitrothion group and lower RBC cholinesterase activity than the EPN group. Patients poisoned with EPN or dichlorvos had significantly higher inhibition of BChE activities from baseline than RBC AChE activities at presentation. Twenty four hours after administration of pralidoxime, RBC AChE activities had increased in patients in the dichlorvos and EPN groups, while RBC AChE activities had slightly decreased in the fenitrothion group. BChE activities increased significantly in the dichlorvos group but decreased in the EPN group. The recovery patterns of RBC AChE and BChE activities did not match in any particular individual. This study showed that the patterns of inhibition and recovery of the activities of two cholinesterases after treatment are highly variable according to the organophosphate and in different individuals.

Balloon-occluded retrograde transvenous obliteration for recurrent fundal gastric variceal bleeding in an adolescent

Gastric variceal bleeding is associated with high morbidity and mortality. Balloon-occluded retrograde transvenous obliteration is a relatively new treatment used to control bleeding gastric varices that involves transvenous sclerosis of gastric varices through a spontaneous gastrorenal shunt. Here, we report on a 14-yr-old patient that underwent balloon-occluded retrograde transvenous obliteration for refractory bleeding fundal varices in the setting of esophageal varices and cirrhosis, which did not respond to medical management or endoscopic injection. This case report serves as a reminder that balloon-occluded retrograde transvenous obliteration can successfully control fundal variceal bleeding in pediatric patients and may serve as a bridge to liver transplantation.

Jeor S, Almeida-Porada G. Perivascular stromal cells as a potential reservoir of human cytomegalovirus

Human cytomegalovirus (HCMV) infection is an important cause of morbidity and mortality among both solid organ and hematopoietic stem cell transplant recipients. Identification of cells throughout the body that can potentially serve as a viral reservoir is essential to dissect mechanisms of cell tropism and latency and to develop novel therapies. Here, we tested and compared the permissivity of liver-, brain-, lung (LNG)- and bone marrow (BM)-derived perivascular mesenchymal stromal cells (MSC) to HCMV infection and their ability to propagate and produce infectious virus. Perivascular MSC isolated from the different organs have in common the expression of CD146 and Stro-1. While all these cells were permissive to HCMV infection, the highest rate of HCMV infection was seen with LNG-MSC, as determined by viral copy number and production of viral particles by these cells. In addition, we showed that, although the supernatants from each of the HCMV-infected cultures contained infectious virus, the viral copy number and the quantity and timing of virus production varied among the various organ-specific MSC. Furthermore, using quantitative polymerase chain reaction, we were able to detect HCMV DNA in BM-MSC isolated from 7 out of 19 healthy, HCMV-seropositive adults, suggesting that BM-derived perivascular stromal cells may constitute an unrecognized natural HCMV reservoir.

Clinical-scale isolation of interleukin-2-stimulated liver natural killer cells for treatment of liver transplantation with hepatocellular carcinoma

Tumor recurrence is the main limitation of liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) and can be promoted by immunosuppressants. However, there is no prevention or treatment for HCC recurrence after LT. Here we describe a clinical-scale method for an adoptive immunotherapy approach that uses natural killer (NK) cells derived from deceased donor liver graft perfusate to prevent tumor recurrence after LT. Liver mononuclear cells (LMNCs) that were extracted from deceased donor liver graft perfusate contained a high percentage of NK cells (45.0 ± 4.0%) compared with peripheral blood mononuclear cells (PBMCs) (21.8 ± 5.2%) from the same donor. The CD69 activation marker and the natural cytotoxicity receptors, NKp44 and NKp46, were expressed at high levels in freshly isolated liver NK cells. Furthermore, interleukin-2 (IL-2)-stimulated NK cells showed greater upregulation of activation markers and the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), which is critical for NK cell-mediated antitumor cell death and increased production of interferon. Moreover, IL-2 stimulation induced LMNCs to exhibit a strong cytotoxicity against NK-susceptible K562 target cells compared with PBMCs (p < 0.01). Finally, we also showed that the final product contained a very low T-cell contamination (0.02 ± 10(6) cells/kg(-1)), which reduces the risk of graft-versus-host disease (GVHD). Collectively, our results suggest that the adoptive transfer of IL-2-stimulated NK cells from deceased donor liver graft perfusate could be a promising treatment for LT patients with HCC.

Development of a fibre-optic dosemeter to measure the skin dose and percentage depth dose in the build-up region of therapeutic photon beams

In this study, a fibre-optic dosemeter (FOD) using an organic scintillator with a diameter of 0.5 mm for photon-beam therapy dosimetry was fabricated. The fabricated dosemeter has many advantages, including water equivalence, high spatial resolution, remote sensing and real-time measurement. The scintillating light generated from an organic-dosemeter probe embedded in a solid-water stack phantom is guided to a photomultiplier tube and an electrometer via 20 m of plastic optical fibre. Using this FOD, the skin dose and the percentage depth dose in the build-up region according to the depths of a solid-water stack phantom are measured with 6- and 15-MV photon-beam energies with field sizes of 10 × 10 and 20 × 20 cm(2), respectively. The results are compared with those measured using conventional dosimetry films. It is expected that the proposed FOD can be effectively used in radiotherapy dosimetry for accurate measurement of the skin dose and the depth dose distribution in the build-up region due to its high spatial resolution.

Spark erosion: a high production rate method for producing Bi(0.5)Sb(1.5)Te3 nanoparticles with enhanced thermoelectric performance

We report a new 'spark erosion' technique for producing high-quality thermoelectric nanoparticles at a remarkably high rate and with enhanced thermoelectric properties. The technique was utilized to synthesize p-type Bi(0.5)Sb(1.5)Te(3) nanoparticles with a production rate as high as 135 g h(-1), using a relatively small laboratory apparatus and low energy consumption. The compacted nanocomposite samples made from these nanoparticles exhibit a well-defined, 20-50 nm size nanograin microstructure, and show an enhanced figure of merit, ZT, of 1.36 at 360 K. Such a technique is essential for providing inexpensive, oxidation-free nanoparticles which are required for the fabrication of high performance thermoelectric devices for power generation from waste heat, and for refrigeration.

Post-transplant lymphoproliferative disorder presented as small bowel intussusception in adult liver transplant patient

Intestinal obstruction after liver transplant is a rare complication, with diverse clinical manifestations. Intestinal adhesion is the most common cause. However, internal hernia, abdominal wall hernia, and neoplasm are also reported. Intussusception is another rare cause of intestinal obstruction, which has been reported primarily in pediatric patients. Herein, we report a case of intestinal obstruction from intussusception in an adult liver transplant patient associated with post-transplant lymphoproliferative disorder.

MicroRNA signature of intestinal acute cellular rejection in formalin-fixed paraffin-embedded mucosal biopsies

Despite continuous improvement of immunosuppression, small bowel transplantation (SBT) is plagued by a high incidence of acute cellular rejection (ACR) that is frequently intractable. Therefore, there is a need to uncover novel insights that will lead to strategies to achieve better control of ACR. We hypothesized that particular miRNAs provide critical regulation of the intragraft immune response. The aim of our study was to identify miRNAs involved in intestinal ACR. We examined 26 small intestinal mucosal biopsies (AR/NR group; 15/11) obtained from recipients after SBT or multivisceral transplantation. We investigated the expression of 384 mature human miRNAs and 280 mRNAs associated with immune, inflammation and apoptosis processes. We identified differentially expressed 28 miRNAs and 58 mRNAs that characterized intestinal ACR. We found a strong positive correlation between the intragraft expression levels of three miRNAs (miR-142-3p, miR-886-3p and miR-132) and 17 mRNAs including CTLA4 and GZMB. We visualized these miRNAs within cells expressing CD3 and CD14 proteins in explanted intestinal allografts with severe ACR. Our data suggested that miRNAs have a critical role in the activation of infiltrating cells during intestinal ACR. These differences in miRNA expression patterns can be used to identify novel biomarkers and therapeutic targets for immunosuppressive agents.

Split liver transplantation

We analyzed the results of 55 patients who underwent split liver transplantation at our center between September 1996 and December 2008, 30 adults (54.5%) and 25 children (45.5%). Median follow-up was 12 years. Overall patient survival was 71%, adult 70% and pediatric 72%. Mean patient survival was 61.58 months, and mean graft survival was 44.35 months. Pediatric survival and pediatric graft survival after 1 and 5 years were 84% and 72% and 72% and 52.4%, respectively. Adult survival and adult graft survival after 1 and 5 years were 75% and 66.2% and 60.7% and 51.5%, respectively. Twelve patients required retransplantation, 6 for primary nonfunction, 3 for chronic rejection, and 3 for vascular complications. Blood groups of the recipient patients were: 34 O, 14 A, 7 B, and 0 AB. The use of split liver for adult and pediatric populations allows us to expand the cadaveric donor pool and has the potential to significantly reduce waiting list mortality, especially for certain blood groups.