In vitro characterization of cells derived from chordoma cell line U-CH1 following treatment with X-rays, heavy ions and chemotherapeutic drugs

<p>Abstract</p> <p>Background</p> <p>Chordoma, a rare cancer, is usually treated with surgery and/or radiation. However, very limited characterizations of chordoma cells are available due to a minimal availability (only two lines validated by now) and the extremely long doubling time. In order to overcome this situation, we successfully derived a cell line with a shorter doubling time from the first validated chordoma line U-CH1 and obtained invaluable cell biological data.</p> <p>Method</p> <p>After isolating a subpopulation of U-CH1 cells with a short doubling time (U-CH1-N), cell growth, cell cycle distribution, DNA content, chromosome number, p53 status, and cell survival were examined after exposure to X-rays, heavy ions, camptothecin, mitomycin C, cisplatin and bleocin. These data were compared with those of HeLa (cervical cancer) and U87-MG (glioblastoma) cells.</p> <p>Results</p> <p>The cell doubling times for HeLa, U87-MG and U-CH1-N were approximately 18 h, 24 h and 3 days respectively. Heavy ion irradiation resulted in more efficient cell killing than x-rays in all three cell lines. Relative biological effectiveness (RBE) at 10% survival for U-CH1-N was about 2.45 for 70 keV/μm carbon and 3.86 for 200 keV/μm iron ions. Of the four chemicals, bleocin showed the most marked cytotoxic effect on U-CH1-N.</p> <p>Conclusion</p> <p>Our data provide the first comprehensive cellular characterization using cells of chordoma origin and furnish the biological basis for successful clinical results of chordoma treatment by heavy ions.</p

Trial of Brain Redox Imaging and Estimation of Radiation-Induced Redox Change in Mouse Brain

The in vivo T1-weighted contrasting abilities and signal decay behaviors of several nitroxyl contrast agents, which have been used as redox responsive contrast agents in several magnetic resonance-based imaging modalities, in mouse brain were compared. In addition, daily variations of redox behavior in mouse brain after irradiation of X-ray or carbon-ion beams (C-beam) were tried to estimate based on the in vivo reduction rate of amphiphilic nitroxyl contrast agents.Injection solutions of five types of five-membered-ring nitroxyl contrast agents, i.e. 3-carboxy-2,2,5,5-tetramethylpyrrolidine-N-oxyl (CxP), 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl (CmP), 3-methoxy-carbonyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl (MCP), acetoxymethyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl-3-carboxylate (CxP-AM), and 4-(N-methylpiperidine)-2,2,5,5-tetramethylpyrroline-N-oxyl (23c), and a six-membered-ring nitroxyl contrast agent, i.e. 4-hydroxyl-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPOL), were prepared. The nitroxyl contrast agent was i.v. injected to a mouse through tail vein. Then, the distributions and pharmacokinetics of nitroxyl contrast agents were compared based on the time course of T1-weighted MRI. The MRI experiments using CMP or TEMPOL were repeated for mice irradiated by X-ray or C-beam to their head on several deferent timings, i.e. 1, 2, 4, 8 day(s) after irradiation. C-beam was irradiated at Heavy-Ion Medical Accelerator in Chiba (HIMAC, National Institute of Radiological Sciences/ National Institutes for Quantum and Radiological Science and Technology).The blood-brain-barrier (BBB)-impermeable CxP could not be distributed in the brain. The slightly lipophilic CmP showed slight distribution only in the ventricle, but not in the medulla and cortex. The amphiphilic MCP and TEMPOL had good initial uniform distribution in the brain and showed typical 2-phase signal decay profiles. A brain-seeking nitroxyl probe, CxP-AM, showed an accumulating phase, and then its accumulation was maintained in the medulla and ventricle regions, but not in the cortex. The lipophilic 23c was well distributed in the cortex and medulla, but slightly in the ventricle, and showed relatively rapid linear signal decay.Decay rates of MCP in mouse brain after irradiation of 8 Gy X-ray, 8 Gy C-beam or 16 Gy C-beams did not show marked clear changes, however relatively little decreasing were observed at day 1 and day 2 after irradiation. Decay rates of TEMPOL was increased 1 after irradiation then gradually recovered to the control level. MCP and TEMPOL showed opposite responses but the timing of redox change may be 1 or 2 days after irradiation.Nitroxyl contrast agents equipped with a suitable lipophilic substitution group could be BBB-permeable functional contrast agents. MR redox imaging, which can estimate not only the redox characteristics but also the detailed distribution of the contrast agents, is a good candidate for a theranostic tool. Irradiation of ionized radiation to head could cause alternation of redox status in the brain. Detail of redox mechanisms were still in progress.第7回国際放射線神経生物学会大

Wie nicht-lineare Zeitrepräsentationen zukunftsbezogene Urteile und Entscheidungen beeinflussen können : ein entwicklungspsychologischer Ansatz

Die vorliegende Arbeit untersuchte in drei Experimenten den Einfluss der Zeit auf Bewertungen und Entscheidungen in unterschiedlichen Altersstufen. Experiment 1 beschäftigte sich mit dem Einfluss des Zeithorizontes auf die Beurteilung der Riskantheit einer Investition sowie auf das Investitionsverhalten bei 12-Jährigen. Im Gegensatz zu typischen Ergebnissen von Erwachsenen führte bei den Kindern eine lange Zeitspanne zwischen Investition und Erfolgsfeedback zur Annahme eines höheren Risikos und damit zu geringeren Investitionen. In Experiment 2 wurde die Bewertung materieller und nicht-materieller Werte, deren Erhalt verzögert war, bei 12-Jährigen und Erwachsenen untersucht. Dabei zeigte sich, dass Erwachsene Geld als materiellen Wert und Hilfe als nicht-materiellen Wert in ähnlicher Weise mit zunehmender Verzögerung abwerteten. Die Kinder hingegen werteten das verzögerte Geld deutlich stärker ab als Erwachsene, die Hilfe jedoch gar nicht. In Experiment 3 wurde die Entwicklung des Wissens über exponentielles Mengenwachstum in verschiedenen Altersgruppen untersucht. So schätzten 13-Jährige ein solches Wachstum normativ, doch bereits 9-Jährige unterschieden in ihren Schätzungen bedeutsam zwischen exponentiellem und linearem Wachstum, was für ein frühes intuitives Wissen in diesem Bereich spricht. Im Anschluss wurde ein Modell zur altersabhängigen Zeitrepräsentation entwickelt, das versucht, den Einfluss der Zeitrepräsentation in allen drei Experimenten zu erklären. Three experiments were conducted to examine the role of time on judgments and decisions in different age groups. Experiment 1 investigated the influence of the time horizon on 12-year-olds judgments of riskiness and amount of investment into an endeavour. In contrast to typical results of adults, a long time span between the investment and a feedback about its success yielded judgments of higher riskiness and, thus, lower investments in children. Experiment 2 assessed 12-year-olds and adults evaluation of material and immaterial values, whose receipt was either immediate or delayed. Results showed similar subjective discount rates for delayed money (i.e. material value) and delayed help (i.e. immaterial value) in adults. However, children discounted the delayed money more than adults, but they devaluated the delayed help not at all. Experiment 3 investigated the development of knowledge about exponential growth in children, aged 7 to 13 years, and adults. Only 13-year-olds showed a normative estimation of exponential growth. However, 9-year-olds already differentiated between exponential and linear growth in their estimations. This result points to an early intuitive knowledge in this domain. Finally, a model of age-related time representation was proposed to explain the role of time representation in the three experiments

Markov models for the evolution of duplicate genes, and microsatellites

Duplicate genes and microsatellites are two key sequences in the study of evolutionary genomics. Gene duplication has been identified as a central process driving functional change in genomes, since it creates functional redundancy in the genome and allows for subsequent mutation to occur in the absence of selective pressure. Microsatellites are rapidly evolving sequences which can be studied over much smaller timescales than most other sequences, and are thus key to the study of population demographics and forensic science. In this thesis we construct mathematical models for the evolution of duplicate genes, and microsatellites, respectively. We analyse the models in order to make scientific predictions, and derive the following novel results. We introduce and analyse a modified hazard function, which we use to investigate the preservation of gene duplicates. Further, we construct individual-level models, and present a framework for the extension to population-level models. Also, we construct mappings from mechanistically-motivated intuitive models for gene duplicate evolution, to less intuitive models, which have smaller state spaces and hence are more computationally tractable. Throughout this analysis, we make scientific predictions based on the properties of the models. We find that the pattern of gene duplicate preservation is more consistent with subfunctionalization than with neofunctionalization. This result is of particular scientific interest, since it is the opposite conclusion of earlier work in the gene duplication literature. ${Duplicate}$ ${genes}$ Several biological models exist for the evolution of a pair of duplicate genes after a duplication event, and it is believed that gene duplicates can evolve in different ways, according to one process, or a mix of processes. Subfunctionalization is a process under which the two duplicates can be preserved by dividing up the functions of the original gene between them. Here, we find that subfunctionalization is highly consistent with the pattern of gene duplicate preservation, in contrast to previous analysis in the literature. Another process important to gene duplicate evolution is neofunctionalization, under which both duplicates can be preserved when one copy mutates so as to produce some new beneficial function. Our analysis of neofunctionalization suggests that this process is not a significant contributor to the preservation of duplicates over the timescales during which regulatory subfunctionalization is resolved. Instead, it is likely that neofunctionalization occurs subsequent to previous subfunctionalization, which acts to preserve copies over the longer time frames required for rare beneficial mutations to have any significant probability of occurring. Analysis of genomic data using sub- and neofunctionalization models has thus far been relatively coarse-grained, with mathematical treatments usually focusing on the phenomenological features of gene duplicate evolution. In contrast, we develop mechanistically motivated Markov models, and fit directly to duplicate preservation data. We introduce a modified-cause-specific hazard function to analyse the preservation of gene duplicates. In the context of gene duplication, we refer to this as the pseudogenization rate, owing to the biological interpretation. We analyse the properties of the modified-cause-specific hazard rate in detail, including limit analysis of the general case, and discuss the shape properties of the specific case of the pseudogenization rate. Further, we extend our model for the evolution of a pair of gene duplicates to model a population of duplicate pairs, by modelling the birth of such pairs as a homogeneous Poisson process. We show that the age distribution of preserved duplicates follows an inhomogenous Poisson distribution, with its rate function depending on the individuallevel model. We then fit this distribution to count-data of surviving duplicates in the genomes of four animal species. Additionally, we extend the individual-level model to a model that includes the process of neofunctionalization, and next, to a model of subfunctionalization for families of gene duplicates. Finally, we map these intuitive models, to less intuitive but more computationally tractable models, and discuss a number of related computational considerations. ${Microsatellites}$ Microsatellites are repetitive regions of DNA where a short motif is repeated many times. Mutations in the number of repeat units occur frequently compared to point mutations and thus provide a useful source of genetic variation for studying recent events. Empirical studies have suggested that the rate of length-changing mutations due to slipped-strand mispairing may depend on the purity of the repeat units, i.e. how well they each match the motif. However, most studies that use microsatellite data are based on models that only track the number of repeat units. In order to address this gap, we introduce a series of models on a two-dimensional state-space (which are level-dependent quasi-birth-and-death processes) that track the length of the sequence as the level variable, and the number of interruptions (purity) as the phase variable. Our models account for the biological process of point mutation, and its observed effect on the rate of slipped-strand mispairing. We find that modelling microsatellite purity leads to some complications due to the nature of available data. In terms of the initial model, we discover what constitutes a state-dependent bias in the reporting of repeat sequences by Tandem Repeats Finder (or any similar software used to search whole-genomes for microsatellite sequences). Consequently, we construct a modified model such that all states fall into one of two categories - 'observable states', against which the reporting algorithm is unbiased, and 'unobservable states', which are never reported. We consider two approaches for treating the unobservable states, first to condition on the process being in the observable states, second to treat unobservable states as absorbing. Our initial analysis and underlying biological intuition suggest that transitions from the unobservable to observable states are very rare, and thus we ultimately treat the unobservable states as absorbing. Additionally, we extend the individual-level model to a population-level model by modelling the birth of microsatellites as a homogeneous Poisson process. We then derive the transient distribution of such model in terms of the individual-level process. This distribution has appropriate relative clock via the inclusion of point mutation. We fit this transient distribution to whole-genome derived sequence data, however we encounter some dificulties in the optimisation owing to the presence of many local optima. The standard approach for microsatellite models is to make the assumption that the empirical distribution is at equilibrium, and then to fit the stationary distribution to data. The key exception to this is the step-wise mutation model, which predicts infinite growth of the repeat number. Here we fit the above-mentioned transient distribution, and thus do not assume that the empirical distribution is at equilibrium. In contrast to the step-wise mutation model, our model does not predict infinite sequence lengths in the long run

Five-year quality of life assessment after carbon ion radiotherapy for prostate cancer

The aim of this study was to prospectively assess 5-year health-related quality of life (HRQOL) of patients treated with carbon ion radiotherapy (C-ion RT) for clinically localized prostate cancer. A total of 417 patients received carbon ion radiotherapy at a total dose of 63–66 Gray-equivalents (GyE) in 20 fractions over 5 weeks, and neoadjuvant and adjuvant androgen deprivation therapy (ADT) were administered for intermediate and high-risk patients. A HRQOL assessment was performed at five time points (immediately before the initiation of C-ion RT, immediately after, and at 12, 36 and 60 months after completion of C-ion RT) using Functional Assessment of Cancer Therapy (FACT) questionnaires. FACT-G and FACT-P scores were significantly decreased; however, the absolute change after 60 months was minimal. The transient decreases in the Trial Outcome Index (TOI) score returned to their baseline levels. Use of ADT, presence of adverse events, and biochemical failure were related to lower scores. Scores of subdomains of FACT instruments indicated characteristic changes. The pattern of HRQOL change after C-ion RT was similar to that of other modalities. Further controlled studies focusing on a HRQOL in patients with prostate cancer are warranted

Significant impact of biochemical recurrence on overall mortality in patients with high-risk prostate cancer after carbon-ion radiotherapy combined with androgen deprivation therapy

BACKGROUNDWhether biochemical recurrence (BR) is a significant predictive factor of mortality after definitive radiation therapy for prostate cancer remains unknown. The aim of the current study was to investigate the relation between BR and overall mortality (OAM) in high-risk prostate cancer patients who were treated with carbon-ion radiotherapy (CIRT) and had long-term follow-up in 2 prospective trials.METHODSIn the 2 phase 2 clinical trials, which involved 466 prostate cancer patients who received 63.0 to 66.0 Gy of CIRT (relative biological effect) in 20 fractions between 2000 and 2007, 324 patients who were deemed to be at high risk on the basis of the modified D\u27Amico classification criteria and received CIRT along with androgen-deprivation therapy (ADT) were examined. The OAM rate was adjusted for the ADT duration, and multivariate analyses using a Cox proportional hazards model were performed for OAM with BR as a time-dependent covariate.RESULTSThe median follow-up period was 107.4 months, and the 5- and 10-year OAM rates after adjustments for the ADT duration were 7.0% (95% confidence interval [CI], 4.0%-9.4%) and 23.9% (95% CI, 16.4%-26.2%), respectively. A multivariate analysis revealed that the presence of BR (hazard ratio, 2.82; 95% Cl, 1.57-5.08; P = .001) was one of the predictive factors for OAM. On the other hand, the duration of ADT had no impact on OAM.CONCLUSIONSBR after CIRT combined with ADT is an independent predictive factor for OAM in high-risk prostate cancer patients. The results of this study could be applied to other high-dose radiation therapies