Analysis of Mutations in the Human HPRT Gene Induced by Accelerated Heavy-Ion Irradiation

Multiplex PCR analysis of HPRT(-) mutations in human embryo (HE) cells induced by 230 keV/μm carbon-ion irradiation showed no large deletion around the exon regions of the locus gene in contrast to the irradiations at different LETs. To identify these mutations, the sequence alterations in a cDNA of hprt gene were determined for 18 mutant clones in this study. Missing of exon 6 was the most frequent mutational event (10 clones), and missing of both exons 6 and 8 was next most frequent event (6 clones), then base substitutions (2 clones). These characteristics were not seen in a similar analysis of spontaneous mutations, which showed base substitution (5 clones), frameshift (2 clones), missing of both exons 2 and 3 (2 clones), and a single unidentified clone. Direct sequencing and restriction enzyme digestion of the genomic DNA of the mutants which showed missing of exons 6 and 8 in the cDNA, supports the possibility that they were induced by aberrant mRNA splicing

Analysis of Mutations in the Human HPRT Gene Induced by Accelerated Heavy-Ion Irradiation

Multiplex PCR analysis of HPRT(-) mutations in human embryo (HE) cells induced by 230 keV/μm carbon-ion irradiation showed no large deletion around the exon regions of the locus gene in contrast to the irradiations at different LETs. To identify these mutations, the sequence alterations in a cDNA of hprt gene were determined for 18 mutant clones in this study. Missing of exon 6 was the most frequent mutational event (10 clones), and missing of both exons 6 and 8 was next most frequent event (6 clones), then base substitutions (2 clones). These characteristics were not seen in a similar analysis of spontaneous mutations, which showed base substitution (5 clones), frameshift (2 clones), missing of both exons 2 and 3 (2 clones), and a single unidentified clone. Direct sequencing and restriction enzyme digestion of the genomic DNA of the mutants which showed missing of exons 6 and 8 in the cDNA, supports the possibility that they were induced by aberrant mRNA splicing

In vivo tau PET imaging using [11C]PBB3 in patients with PSP and CBS

Objective: To investigate characteristics of [11C]PBB3 binding andits relation with clinical aspects in patients with progressivesupranuclear palsy (PSP) and corticobasal syndrome (CBS).Background: [11C]PBB3 is a novel tau imaging positron emissiontomography (PET) ligand, which could visualize the tau deposition inAlzheimer’s disease (AD) and non-AD tauopathies such as PSP,CBS and frontotemporal dementia.Methods: Participants included 10 PSP patients, 9 patients withcorticobasal syndrome (CBS), 19 AD patients, and 20 age andgender matched healthy controls (HCs). A dose (about 10 mCi) of[11C]PBB3 was intravenously injected and sequential PET scanswere performed for 70 min. We also performed PET scan with aplaque-binding agent, [11C]PIB (about 10 mCi), for 70 min and threedimensionalT1-weighted MRI. Standardized uptake value ratio(SUVR) was calculated for each PET image using the cerebellarcortex as reference region. Amyloid deposition was verified by visualassessment of SUVR images of [11C]PIB PET. As for [11C]PBB3PET data, group analysis among each group was performed by onewayANOVA using statistical parametric mapping software (spm5).Results: One CBS patient and 17 of 19 AD patients were PIBpositive,and all the rest participants were PIB-negative. One PIBpositiveCBS and two PIB-negative AD patients were excluded fromgroup analysis. [11C]PBB3 was accumulated in lesions associatedwith neurological symptoms in PSP, CBS and AD patients. To bespecific, [11C]PBB3 binding was significantly increased in thebrainstem, basal ganglia, thalamus and dentate nucleus in PSPpatients compared to HCs. In PIB-negative CBS patients,remarkable uptake of [11C]PBB3 was observed in basal ganglia andthe neocortex including the supplementary motor area (SMA) andthe peri-Rolandic area compared to HCs. Furthermore, [11C]PBB3retention observed in PIB-positive CBS patient extended theneocortex as well as the entire limbic system, resembling ADpatients with profound cognitive decline. Some brain lesions with[11C]PBB3 binding exhibited brain atrophy in PSP, CBS and ADpatients.Conclusions: The present study demonstrated that distributionpatterns of [11C]PBB3 binding reflect the differences in taudistribution in PSP, CBS and AD patients, which are highlycompatible with neurological manifestation in each disorder.第18回国際パーキンソン病・運動障害疾患会議（MDS2014

In vivo visualization of tau pathology in Alzheimer’s disease patients by [11C]PBB3-PET

not availableWorld Congress of Neurolog

Tau tangles estimated by PET reflect a dementia severity in Alzhiemr\u27s disease.

Objectives:[11C]PBB3 is a novel tau imaging PET ligand, showing high affinity and selectivity for tau deposits. The aim of the present study was to investigate characteristics of [11C]PBB3 binding and its relation with clinical aspects in cognitively healthy subjects and patients with cognitive impairments.Methods:Participants included 17 AD patients, 15 mild cognitive impairments (MCI) patients and 17 age and gender matched cognitively healthy controls (HCs). The PET study was approved by the institutional review board. Written informed consent was obtained from all subjects. PET scans with [11C]PBB3 and an amyloid radioligand, [11C]PIB, and T1-weighted MRI were performed for each individual. Standardized uptake value ratio (SUVR) was calculated for PET images using the cerebellar cortex as reference region. Tau and amyloid deposits were visually assessed using SUVR images for [11C]PBB3 and [11C]PIB, respectively. Correlation between clinical dementia rating scale (CDR) sum of boxes and mean cortical [11C]PBB3 or [11C]PIB SUVR was analyzed among [11C]PIB-positive MCI and AD patients.Results:All HCs and 6 MCI patients were [11C]PIB-negative, and all AD patients and 9 of 15 MCI patients were [11C]PIB-positive. [11C]PBB3 was highly accumulated in the medial temporal cortex of all AD and [11C]PIB-positive MCI patients, in contrast to the modest binding of [11C]PIB in the corresponding region. Distribution of [11C]PBB3 accumulation observed in [11C]PIB-positive MCI patients was restricted within the temporal cortex, while AD patients showed [11C]PBB3 accumulation extending to the neocortex. Some HCs showed accumulation of [11C] PBB3 in the temporal cortex, despite no increase in cortical [11C]PIB binding. Dementia severity (CDR sum of boxes) among AD and [11C]PIB-positive MCI patients showed significant positive correlation with mean cortical [11C]PBB3 binding, but no association with [11C]PIB binding measures..Conclusions:Distribution of [11C]PBB3 binding observed in AD and [11C]PIB-positive MCI patients extended from the temporal area to the entire limbic system and subsequently to the neocortex as a function of disease severity. Some HCs showed noticeable [11C]PBB3 binding in the limbic system, implying that tau deposition may be initiated in a manner independent of amyloid accumulation.第55回日本神経学会学術大