Plasminogen activators, such as recombinant tissue-type plasminogen activators (rtPAs), while effective in treating thromboembolic diseases, often induce hemorrhagic complications due to non-specific enzyme activities in the systemic circulation. This study evaluated the targeting efficiency, efficacy, biodistribution, and potential toxicity of a rtPA covalently attached to chitosan-coated magnetic nanoparticles (chitosan-MNP-rtPA). The thrombolytic activity of a chitosan-MNP-rtPA was preserved by protection from an endogenous plasminogen activator inhibitor-1 (PAI-1) in whole blood and after circulation in vivo, as examined by thromboelastometry. Single-photon emission computed tomography (SPECT) demonstrated real-time retention of a 99mTc-MNP-rtPA induced by magnet application in a rat embolic model; an 80% reduction in rtPA dosage for a chitosan-MNP-rtPA with magnetic guidance was shown to restore blood flow. After treatment, iron deposition was observed in the reticuloendothelial systems, with portal edema and neutrophil infiltration in the liver at a ten-fold higher dose but not the regular dose. Nevertheless, no liver or renal toxicity was observed at this higher dose. In conclusion, the liver may still be the major deposit site of rtPA nanocomposites after targeted delivery; chitosan-coated MNPs are potentially amenable to target therapeutics with parenteral administration.

Without conjunctive administration of an anticoagulant, endothelial injury-induced thrombosis is resistant to thrombolysis and prone to re-thrombosis. We hypothesized that co-delivery of recombinant tissue plasminogen activator (rtPA) with annexin V-containing anticoagulants that specifically target the injured endothelium may passivate the thrombogenic elements of the vascular injury site and enhance rtPA-induced thrombolysis. In this study, the effects of conjunctive administration of Kinexins (Kunitz inhibitor-annexin V fusion proteins) with rtPA on thrombolysis were determined in vitro and in vivo. Thromboelastometry showed that both TAP-A (tick anticoagulant peptide-annexin V fusion protein; an inhibitor of factor Xa [FXa] and prothrombinase) and A-6L15 (annexin V-6L15 fusion protein; an inhibitor of tissue factor/FVIIa) exerted concentration-dependent (10-100 nM) effects on clot formation, with TAP-A being several folds more potent than A-6L15 in whole blood. Combination of TAP-A or A-6L15 with rtPA (1 μg/mL) led to decrease in lysis index, suggesting conjunctive enhancement of thrombolysis by combined use of rtPA with TAP-A or A-6L15. In a rat cremaster muscle preparation subjected to photochemical injury, conjunctive administration of rtPA and TAP-A significantly restored tissue perfusion to 56%, which is approximately two fold of that by rtPA or TAP-A alone. Near-infrared fluorescence images demonstrated local retention of a fluorescent A-6L15-S288 at the injury site, suggesting a targeting effect of the fusion protein. Pharmacokinetic analysis showed that 123I-labelled TAP-A and A-6L15 had initial distribution half-lives (T1/2α) of approximately 6 minutes and elimination half-lives (T1/2β) of approximately 2.3 hours. In conclusion, Kinexins were potentially useful adjunctive agents with rtPA thrombolytic therapy especially for thrombosis induced by endothelial injury.

Parkinson's disease (PD) is a profound neurodegenerative disorder with gradual loss of dopamine nigrostriatal neurons linked to serious behavioral symptoms. While the current treatment strategies present limitations on halting the progression of PD, this study aimed to investigate the therapeutic potential of honokiol, as a partial peroxisome proliferator-activated receptor-gamma (PPARγ) mimic, on the proceeding behavioral and biochemical alterations in hemiparkinsonian mice. Results showed that unilateral striatal 6-hydroxydopamine (6-OHDA)-lesioned mice exhibited motor impairment, reflecting the contralateral rotation induced by apomorphine at 1-3 weeks post-lesion. Subchronic honokiol administration for 1-2 weeks, beginning 7 days after 6-OHDA-lesion, dose-dependently ameliorated motor dysfunction in hemiparkinsonian mice. Recovery of motor function was correlated with reversal of nigrostriatal dopaminergic neuronal loss, accompanied by higher tyrosine hydroxylase (TH) density, dopamine transporter (DAT) expression and vesicular monoamine transporter-2 (VMAT2) levels. Furthermore, honokiol attenuated oxidative stress and reactive astrocyte induction via decreasing NADPH-oxidase and glial fibrillary acidic protein (GFAP) expressions in 6-OHDA-lesioned striatum. The reversal effects of honokiol on behavioral impairment and striatal PPARγ expression were impeded by PPARγ antagonist GW9662. Notably, subchronic honokiol treatment extended the lifespan of these hemiparkinsonian mice. The present findings demonstrate the therapeutic activities of honokiol in ameliorating motor impairment and progressive dopaminergic damage that could be associated with regulating PPARγ signaling. Therefore, honokiol may potentially exert as a novel therapeutic candidate through PPARγ activation for management of motor symptoms and progressive neurodegeneration in PD.

The 18F-THK-5351 radiotracer has been used to detect the in vivo tau protein distribution in patients with tauopathy, such as Alzheimer’s disease and corticobasal syndrome. In addition, 18F-THK-5351 can also monitor neuroinflammatory process due to high affinity to astrogliosis. We aimed to explore 18F-THK-5351 distribution patterns and characteristics in patients with recent ischemic stroke.

Background: Visual association memory test (VAMT) is a brief 6-point cognition test that has been shown to be effective in differentiating Alzheimer's disease (AD) from other types of dementia. This study aimed to investigate the correlation of the VAMT performance with amyloid plaque burden and hippocampal atrophy. Methods: Fourteen patients with AD, 29 with amnestic mild cognitive impairment (aMCI), and 11 normal cognition (NC) subjects were recruited. Brain magnetic resonance imaging (MRI) and [18F]AV-45 positron emission tomography (PET) were performed to evaluate hippocampal atrophy and amyloid plaque burden. Results: The VAMT median score and interquartile range of the NC, aMCI and AD groups were 6 (6-6), 2 (0-4), and 0 (0-1), respectively (p < 0.001). The hippocampal atrophy was correlated with VAMT results across each group. The VAMT score was correlated with the occipital and parietal cortical [18F]AV-45 uptake in the NC group, and with the frontal, parietal and precuneus uptake in the aMCI group. However, no correlation between VAMT score and [18F]AV-45 uptake was found in the AD group. Conclusion: The VAMT can be an adjunctive cognitive test to identify patients with AD, and the early amyloid plaque accumulation is correlated with VAMT scores in patients with aMCI and even NC subjects. Copyright (C) 2018, Formosan Medical Association. Published by Elsevier Taiwan LLC.

Background: Late-phase 18F-AV-45 PET imaging (AV-45) can visualize the extracellular amyloid plaques, while early-phase 18F-AV-45 PET imaging can provide perfusion-like property (pAV-45) for the estimation of cerebral blood flow.

18F-9-Fluoropropyl-(+)-dihydrotetrabenazine [18F-FP-(+)-DTBZ] positron emission tomography (PET) has been shown to detect dopaminergic neuron loss associated with Parkinson's disease (PD) in human and neurotoxin-induced animal models. A polyphenol compound, magnolol, was recently proposed as having a potentially restorative effect in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)- or 6-hydroxydopamine-treated animal models. In this study, 18F-FP-(+)-DTBZ PET was used to determine the therapeutic efficacy of magnolol in an MPTP-PD mouse model that was prepared by giving an intraperitoneally (i.p.) daily dose of 25 mg/kg MPTP to male C57BL/6 mice for 5 consecutive days. Twenty-minute static 18F-FP-(+)-DTBZ PET scans were performed before MPTP treatment and 5 days after the termination of MPTP treatment to set up the baseline control. Half of the MPTP-treated mice then received a daily dose of magnolol (10 mg/kg dissolved in corn oil, i.p.) for 6 days. 18F-FP-(+)-DTBZ PET imaging was performed the day after the final treatment. All 18F-FP-(+)-DTBZ PET images were analysed and the specific uptake ratio (SUr) was calculated. Ex vivo autoradiography (ARG) and corresponding immunohistochemistry (IHC) studies were conducted to confirm the distribution of dopaminergic terminals in the striatum. The striatal SUr ratios of 18F-FP-(+)-DTBZ PET images for the Sham, the MPTP, and the MPTP + Magnolol-treated groups were 1.25 ± 0.05, 0.75 ± 0.06, and 1.00 ± 0.11, respectively (n = 4 for each group). The ex vivo 18F-FP-(+)-DTBZ ARG and IHC results correlated favourably with the PET imaging results. 18F-FP-(+)-DTBZ PET imaging suggested that magnolol post-treatment may reverse the neuronal damage in the MPTP-lesioned PD mice. In vivo imaging of the striatal vesicular monoamine transporter type 2 (VMAT2) distribution using 18F-FP-(+)-DTBZ animal PET is a useful method to evaluate the efficacy of therapeutic drugs i.e., magnolol, for the management of PD.

Lactacystin has been used to establish rodent models of Parkinson disease (PD), with cerebral α-synuclein inclusions. This study evaluated the uptake of [18F]9-fluoropropyl-(+)-dihydrotetrabenazine ([18F]FP-(+)-DTBZ), a vesicular monoamine transporter type 2 (VMAT2)-targeting radiotracer, through positron emission tomography (PET) in lactacystin-treated rat brains.

Nuclear reactions of high-energy protons with treatment equipment, air, and patient tissue during proton therapy generate residual radioactivity and secondary particles including protons, deuterons, alphas, and neutrons. The most up-to-date versions of INCL++ (v5.2.9), TALYS (v1.8), EMPIRE (v3.2.2 Malta), and ALICE/ASH were used in this study to calculate the excitation functions of proton-induced reactions with carbon, nitrogen, oxygen, aluminum, calcium, iron, nickel, copper, zinc, tin, tungsten, and lead nuclei. The cross sections of different nuclear reaction mechanisms, gamma particles, and residual radionuclides were calculated. The obtained results were compared with available experimental data and the ENDF/B-VII.1.

Purpose: One of the promising radiosensitizers is the ultrasmall gold nanoparticle (GNP) with a hydrodynamic diameter <3 nm. We studied functionalized ultrasmall GNPs (1.8 nm diameter) coated by polyethylene glycol (PEG) and conjugated with cyclic RGDfK (2.6nm hydrodynamic diameter) for targeting of alpha(v) beta(3) integrin (alpha(v)beta(3)) in the murine ALTS1C1 glioma cell line. Materials and methods: We investigated the uptake, toxicity and radiosensitivity of GNP-PEG-cRGDfKs in ALTS1C1 cells exposed to protons, kilovoltage photons and megavoltage photons. The in vitro uptake and toxicity of GNPs in the hepatocytes and Kupffer cells were assessed for murine AML12 hepatocyte and RAW 264.7 macrophage cell lines. The in vivo biodistribution of GNPs in the ALTS1C1 tumor model was tested using the inductively coupled plasma mass spectrometry. Results: Results indicated GNPs accumulated in the cytoplasm with negligible toxicity for a moderate concentration of GNPs. Observed sensitizer enhancement ratios and dose enhancement factors are 1.21-1.66 and 1.14-1.33, respectively, for all radiations. Conclusion: Ultrasmall GNP-PEG-cRGD can be considered as a radiosensitizer. For radiotherapy applications, the delivery method should be developed to increase the GNP uptake in the tumor and decrease the uptakes in undesirable organs.

BACKGROUND:Carotid artery stenosis (CAS) may induce cerebral hypoperfusion. Early-phase 18F-Florbetapir (AV-45/Amyvid, 18F-AV-45) positron emission tomography (PET) imaging can provide perfusion-like property (pAV-45) for the estimation of cerebral blood flow (CBF). Supra-tentorial lesions may cause decreased blood flow and metabolism in the contralateral cerebellum known as crossed cerebellar diaschisis (CCD).OBJECTIVE:The aim was to study the occurrence of CCD after CAS using pAV-45 PET.METHODS:Eleven healthy controls and 21 patients with unilateral CAS were studied. All subjects underwent 18F-AV-45 PET imaging and arterial spin labeling (ASL) CBF magnetic resonance perfusion imaging. The pAV-45 and ASL CBF values were first correlated. Then, cerebral and cerebellar hypoperfusion volume was analyzed. The cerebral and cerebellar perfusion asymmetry indices (AIs) were calculated from the pAV-45 standard uptake value ratios (SUVRs) of bilateral cerebral and cerebellar cortices, respectively.RESULTS:We found that pAV-45 SUVR was significantly correlated to ASL CBF (p&lt;0.0001, r=0.5731). The AI of cerebellar perfusion was negatively correlated to that of cerebral perfusion (p&lt;0.0001, r=-0.8751). Multiple linear regression showed the cerebral AI (p&lt;0.0001) and hypoperfusion volume (p=0.02) but not the infarction severity and CAS degree significantly correlated to cerebellar AI. If the lower limit of 95% confidence interval of cerebellar AI in healthy controls was set as cut-off for positive CCD, the occurrence of CCD correlated to infarction severity in CAS patients (p=0.03).CONCLUSION:Our results suggest pAV-45 is reliable to study CBF change. Under unilateral CAS, cerebral AI and hypoperfusion severity may determine the occurrence of CCD.

F-18-THK-5351 is a novel radiotracer that demonstrates high binding selectivity and affinity for tau pathology and exhibits better pharmacokinetics in the living brain than previous THK tau probes. The aim of the present study was to estimate the radiation dose of F-18-THK-5351 in humans and to compare the clinical radiation dosimetry results to estimations published previously with preclinical data. Methods: Serial whole-body PET/CT imaging was performed for 240 min on 12 healthy volunteers after injecting F-18-THK-5351 (mean administered activity, 377.8 +/- 14.0 MBq; range, 340-397 MBq). The bladder and gallbladder were delineated on PET images, and the other organs were delineated on CT images. Voided urine activity was recorded. The decay-corrected and normalized F-18-THK-5351 activity of 15 source-organ regions as a function of time was entered into the OLINDA/EXM software to calculate the effective dose for each subject following the medical internal radiation dosimetry schema. Results: Overall, the F-18-THK-5351 injection was well tolerated. The highest mean initial uptake at 10 min after injection was in the liver (11.4% +/- 2.0%), lung (5.7% +/- 2.1%), intestine (3.4% +/- 0.8%), and kidney (1.4% +/- 0.3%). The highest mean absorbed dose of radiation was in the gallbladder wall (242.2 +/- 105.2 mu Gy/MBq), upper large intestine (90.0 +/- 15.8 mu Gy/MBq), small intestine (79.5 +/- 13.8 mu Gy/MBq), and liver (55.8 +/- 6.1 mu Gy/MBq). The resultant whole-body effective dose was 22.7 +/- 1.3 mu Sv/MBq. Conclusion: Our results suggest that a routine injection of 370 MBq of F-18-THK-5351 would lead to an estimated effective dose of 8.4 mSv; hence, F-18-THK-5351 has a radiation burden similar to that of other commonly used clinical tracers. Our findings in humans were compatible with recently published preclinical dosimetry data extrapolated from mice.

18F-THK-5351 is a novel radiotracer demonstrating high binding selectivity and affinity for tau over amyloid pathology and better pharmacokinetics in the brain than previous THK probes. Our aim was to estimate the radiation dose of 18F-THK-5351 in human, and then compare the clinical radiation dosimetry results to estimations in previously published preclinical data. Serial whole body PET/CT imaging was performed over 240 min on 7 healthy volunteers after injection of 377±18.6 MBq (range, 340.7 – 388.9 MBq) of 18F-THK-5351. The bladder and gallbladder were delineated from PET images, and other organs were delineated on CT images. Voided urine activity was recorded. The decay-corrected and normalized 18F-THK-5351 activity of 15 source organ regions as a function of time was entered into the OLINDA/EXM software to calculate the effective dose of each subject following the medical internal radiation dosimetry schema. 18F-THK-5351 injection was well tolerated. The highest mean initial uptakes at 10 minutes post injection were measured in the liver (10.8%), lung (6.1%), kidney (1.5%), and brain (1.0%). The highest mean radiation absorbed doses were received by the gallbladder wall (211mGy/MBq), upper large intestine (93 mGy/MBq) and small intestine (82 mGy/MBq). The resultant whole-body effective dose was 22.0 mSv/MBq. A routine injection of 370 MBq of 18F-THK-5351 would lead to an estimated effective dose of 8.1 mSv, which shows similar radiation burdens to widely used common clinical tracers. The human result was compatible with recently published preclinical dosimetry data extrapolated from mice.

We investigated dual-phase 18F-florbetapir (AV-45/Amyvid) PET imaging for the concomitant detection of brain perfusion deficits and beta-amyloid deposition in patients with Alzheimer’s disease (AD) and amnestic mild cognitive impairment (MCI), and in cognitively healthy controls (HCs).

Successful oral delivery of therapeutic proteins such as insulin can greatly improve the quality of life of patients. This study develops a bubble carrier system by loading diethylene triamine pentaacetic acid (DTPA) dianhydride, a foaming agent (sodium bicarbonate; SBC), a surfactant (sodium dodecyl sulfate; SDS), and a protein drug (insulin) in an enteric-coated gelatin capsule. Following oral administration to diabetic rats, the intestinal fluid that has passed through the gelatin capsule saturates the mixture; concomitantly, DTPA dianhydride produces an acidic environment, while SBC decomposes to form CO2 bubbles at acidic pH. The gas bubbles grow among the surfactant molecules (SDS) owing to the expansion of the generated CO2. The walls of the CO2 bubbles consist of a self-assembled film of water that is in nanoscale and may serve as a colloidal carrier to transport insulin and DTPA. The grown gas bubbles continue to expand until they bump into the wall and burst, releasing their transported insulin, DTPA, and SDS into the mucosal layer. The released DTPA and SDS function as protease inhibitors to protect the insulin molecules as well as absorption enhancers to augment their epithelial permeability and eventual absorption into systemic circulation, exerting their hypoglycemic effects.

Tc-99m-TRODAT-1 is the first clinical routine Tc-99m radiopharmaceutical to evaluate dopamine neurons loss in Parkinson's disease (PD). (18) F-AV-133 is a novel PET radiotracer targeting the vesicular monoamine transporter type 2 (VMAT2) to detect monoaminergic terminal reduction in PD patients. The aim of this study is to compare both images in the same health control (HC) and PD subjects.Methods: Eighteen subjects (8 HC and 10 PD) were recruited for Tc-99m-TRODAT-1 SPECT, (18) F-AV-133 PET and MRI scans within two weeks. The SPECT images were performed at 4-h post-injection for 45 min, and the PET images were performed at 90 min post-injection for 10 min. Each PET and SPECT image was normalized into Montreal Neurological Institute template aided from individual MRI for comparison. For regional analysis, volume of interest (VOIs) of bilateral caudate nuclei, anterior, posterior putamen and occipital cortex (as reference region) were delineated from the normalized MRI. The specific uptake ratio (SUR) was calculated as (regional mean counts/reference mean counts - 1). The nonparametric Mann-Whitney U test was used to evaluate the power of differentiating control from PD subjects for both image modalities. The correlations of the SURs to the clinical parameters were examined. For voxelwise analysis, two-sample t-test for group comparison between HC and PD was computed in both image modalities.Results: The SURs of caudate nucleus and putamen correlated well between two image modalities (r = 0.81, p < 0.001), and showed significant different between HC and PD subjects. Of note, the (18) F-AV-133 SUR displayed a better correlation to PD clinical laterality index as compared to Tc-99m-TRODAT-1 (r = 0.73 vs. r = 0.33). Voxelwise analysis showed more lesions for PD subjects from (18) F-AV-133 image as compared to Tc-99m-TRODAT-1 especially at the substantia nigra region.Conclusion: (18) F-AV-133 PET demonstrated similar performance in differentiation PD from control, and a better correlation to clinical characteristics than that of Tc-99m-TRODAT-1 SPECT. (18) F-AV-133 PET also showed additional information in substantia nigra integrity in PD subjects by voxelwise analysis. Collectively, (18) F-AV-133 could be a promising and better tracer for clinical use to detect monoaminergic terminal reduction in PD patients. (C) 2014 Elsevier Inc. All rights reserved.

ABSTRACT The biodegradation of steroids is a crucial biochemical process mediated exclusively by bacteria. So far, information concerning the anoxic catabolic pathways of androgens is largely unknown, which has prevented many environmental investigations. In this work, we show that Sterolibacterium denitrificans DSMZ 13999 can anaerobically mineralize testosterone and some C 19 androgens. By using a 13 C-metabolomics approach and monitoring the sequential appearance of the intermediates, we demonstrated that S. denitrificans uses the 2,3- seco pathway to degrade testosterone under anoxic conditions. Furthermore, based on the identification of a C 17 intermediate, we propose that the A-ring cleavage may be followed by the removal of a C 2 side chain at C-5 of 17-hydroxy-1-oxo-2,3- seco -androstan-3-oic acid (the A-ring cleavage product) via retro-aldol reaction. The androgenic activities of the bacterial culture and the identified intermediates were assessed using the lacZ -based yeast androgen assay. The androgenic activity in the testosterone-grown S. denitrificans culture decreased significantly over time, indicating its ability to eliminate androgens. The A-ring cleavage intermediate (≤500 μM) did not exhibit androgenic activity, whereas the sterane-containing intermediates did. So far, only two androgen-degrading anaerobes ( Sterolibacterium denitrificans DSMZ 13999 [a betaproteobacterium] and Steroidobacter denitrificans DSMZ 18526 [a gammaproteobacterium]) have been isolated and characterized, and both of them use the 2,3- seco pathway to anaerobically degrade androgens. The key intermediate 2,3- seco -androstan-3-oic acid can be used as a signature intermediate for culture-independent environmental investigations of anaerobic degradation of C 19 androgens.