A Clinically Translatable Mouse Model for Chemotherapy-Related Fatigue

Fatigue is a debilitating and pervasive complication of cancer and cancer care. Clinical research investigating potential therapies is hindered by variability in patient histories, different metrics for measuring fatigue, and environmental factors that may affect fatigue. The purpose of this study was to establish an animal model of chemotherapy-related fatigue. Female HSD:ICR mice were treated with doxorubicin (2.5 mg/kg) or saline in 2 cycles (days 1 through 3 and 10 through 12). After treatment, mice were individually housed in cages equipped with running wheels. Open-field activity and motor coordination were examined after each cycle of treatment and after each week of wheel running. In a separate cohort, modafinil (50 mg/kg) was assessed as a potential treatment for fatigue. Doxorubicin administration resulted in greater than 30% less wheel running compared with that of saline controls. Activity differences were specific to wheel running: neither distance traveled in the open field nor motor coordination according to the rotarod test differed between groups. Compared with control values, RBC counts in the doxorubicin group were decreased on days 15 and 22 but recovered to control levels by study completion. Modafinil was efficacious in increasing wheel running in the doxorubicin group. The current results establish an animal model of chemotherapy-related fatigue that recapitulates the physical symptoms of cancer-related fatigue as manifested as decreased voluntary activity. This model is sensitive to pharmaceutical intervention and can be used to screen potential treatments for fatigue.Abbreviations: CRF, cancer-related fatigueLasting and debilitating fatigue is among the most common side effects of cancer and its treatment.^12,20 It has a profoundly negative effect on patients’ quality of life and is among the most distressing symptoms reported by those undergoing care.^20,31,50 Frustrating for patients and providers is the lack of approved treatment. One hindrance to better understanding the pathogenesis of cancer-related fatigue (CRF), as well as to the development of an effective intervention, has been the lack of an effective translatable animal model of the condition.Few models of CRF have been reported. One study⁶² found that female C57Bl/6J mice displayed significantly reduced wheel running activity after repeated etoposide administration. Because activity was examined only during the course of treatment and one day afterward, the observed changes may have been at least partly attributable to anemia. In addition, the duration of fatigue was not established, given the short examination period after treatment. In another study,⁴⁹ reductions in wheel running activity lasted for as long 3 wk after 5 consecutive administrations of paclitaxel or nab-paclitaxel in female BALB/cJ mice; these changes were independent of anemia. The ability of the model to assess potential interventions was not reported. Some investigators⁴³ reported reduced home cage activity in rats after cisplatin treatment. In a follow-up study, dexamethasone, a synthetic corticosteroid, was found to protect against cisplatin-induced reductions in activity.⁴² Whether anemia contributed to the cisplatin-induced reduction in activity is unclear. In addition, fatigue was short-lived in this model,⁴¹ lasting only 7 d, whereas CRF in patients is often long-lasting and can affect them months to years after treatment.⁸The objective of the current study was to establish a murine model of CRF that replicates the condition in humans by using endpoints that are translatable to clinical trials and that discriminate the effectiveness of a pharmacologic intervention. Such an objective presents 2 major challenges in animal model design. First, whereas fatigue in humans typically is measured by self-report and quantitative scales,^35,45 in rodents the subjective state of the animal must be inferred from their behavior. As a fatigue surrogate, physical activity appears to be a good indicator.²⁹ Voluntary physical activity is particularly appropriate because fatigue most commonly is diagnosed by self-report, and voluntary activity, unlike forced treadmill running, is independent of stressful stimuli that may interact with fatigue. Second, translational validation of a new animal model is dependent on demonstrating that agents that produce an efficacy signal in humans produce a similar response in the model. The absence of an approved treatment for CRF precludes this requirement to some degree. However, several compounds, including methylphenidate and modafinil, have been tested in clinical trials. Although the results for methylphenidate have been mixed,^{10,11,28,41,44,46,53} the results for modafinil have been more promising.^6,57 In a large double-blind phase 3 clinical trial, modafinil was more effective than placebo in treating patients with severe fatigue.³⁷ Therefore, we selected modafinil as a positive control in the current study to assess the predictive validity of the model.Several methods for assessing voluntary activity in rodents have been established, including wheel-running, home-cage activity, burrowing, and open-field activity.^22,51,64 In the current study, we used wheel-running as the primary endpoint for evaluating fatigue. This decision was made in part because wheel-running captures the entire circadian rhythm of activity, and circadian rhythm disruptions are a possible symptom of CRF.³³ Home-cage activity as measured by video recording or telemetry device also captures circadian rhythm.^49,64 However, we chose wheel-running activity over home-cage activity assessments because previous studies have suggested that wheel-running may be more sensitive than is home-cage activity in detecting fatigue.⁴⁹ In addition, baseline wheel-running activity generally is greater than is home-cage activity,^17,64 allowing for a larger window of detection to assess activity reductions.     

A Molecular Predictor Reassesses Classification of Human Grade II/III Gliomas

Diffuse gliomas are incurable brain tumors divided in 3 WHO grades (II; III; IV) based on histological criteria. Grade II/III gliomas are clinically very heterogeneous and their prognosis somewhat unpredictable, preventing definition of appropriate treatment. On a cohort of 65 grade II/III glioma patients, a QPCR-based approach allowed selection of a biologically relevant gene list from which a gene signature significantly correlated to overall survival was extracted. This signature clustered the training cohort into two classes of low and high risk of progression and death, and similarly clustered two external independent test cohorts of 104 and 73 grade II/III patients. A 22-gene class predictor of the training clusters optimally distinguished poor from good prognosis patients (median survival of 13–20 months versus over 6 years) in the validation cohorts. This classification was stronger at predicting outcome than the WHO grade II/III classification (P≤2.8E-10 versus 0.018). When compared to other prognosis factors (histological subtype and genetic abnormalities) in a multivariate analysis, the 22-gene predictor remained significantly associated with overall survival. Early prediction of high risk patients (3% of WHO grade II), and low risk patients (29% of WHO grade III) in clinical routine will allow the development of more appropriate follow-up and treatments.     

放射杂交:一种人类染色体基因定位方法

1.概述染色体基因定位的方法有多种,包括传统的原位杂交中的荧光技术(ｆｌｕｏｒｅｓｃｅｎｔｉｎｓｉｔｕｈｙｂｒｉｄｉｚａｔｉｏｎ,ＦＩＳＨ)[1]和放射杂交(ｒａｄｉａｔｉｏｎｈｙｂｒｉｄ,ＲＨ)定位[2]等。ＲＨ定位解决了传统ＦＩＳＨ定位精度过于粗略(>2Ｍｂ)的缺点,而且成本低、定位效率高。用于ＲＨ定位的细胞系叫放射杂交系。放射杂交系的建立收稿日期:19991119作者简介:杨泉胜(1977—),男,研究生。是用一定剂量的Ｘ射线照射人类双倍体细胞,然后与仓鼠细胞融合形成。这样,仓鼠融合细胞中就存留了一定数量的人类染色体片段。根据辐…     

A Computational Predictor of Human Episodic Memory Based on a Theta Phase Precession Network

In the rodent hippocampus, a phase precession phenomena of place cell firing with the local field potential (LFP) theta is called “theta phase precession” and is considered to contribute to memory formation with spike time dependent plasticity (STDP). On the other hand, in the primate hippocampus, the existence of theta phase precession is unclear. Our computational studies have demonstrated that theta phase precession dynamics could contribute to primate–hippocampal dependent memory formation, such as object–place association memory. In this paper, we evaluate human theta phase precession by using a theory–experiment combined analysis. Human memory recall of object–place associations was analyzed by an individual hippocampal network simulated by theta phase precession dynamics of human eye movement and EEG data during memory encoding. It was found that the computational recall of the resultant network is significantly correlated with human memory recall performance, while other computational predictors without theta phase precession are not significantly correlated with subsequent memory recall. Moreover the correlation is larger than the correlation between human recall and traditional experimental predictors. These results indicate that theta phase precession dynamics are necessary for the better prediction of human recall performance with eye movement and EEG data. In this analysis, theta phase precession dynamics appear useful for the extraction of memory-dependent components from the spatio–temporal pattern of eye movement and EEG data as an associative network. Theta phase precession may be a common neural dynamic between rodents and humans for the formation of environmental memories.     

Inactivation of Cyanobacterial Nitrogenase After Exposure to Ultraviolet-B Radiation

Exposure of the N₂-fixing cyanobacterium Anabaena BT2 to ultraviolet-B radiation (2.5 W m⁻²) for 30 min resulted in complete loss of nitrogenase activity but 100% cell killing occurred only after a 90-min exposure. Inactivation of nitrogenase activity was not specific to Anabaena BT2; other species also showed a similar effect. The time required for 100% killing and inactivation of nitrogenase activity differed in various species, and this difference may be ascribed to the presence of different levels of UV-B protection mechanisms in individual species. Inhibition of nitrogenase activity was immediate, since exposure of cultures to UV-B for as little as 5 min elicited some inhibition of activity. The activity of UV-B-inhibited nitrogenase did not recover upon transfer of exposed cells to fluorescent light, suggesting that the inhibition may be due to specific inactivation of the enzyme. By employment of inhibitors of protein synthesis and PS-II activity, it was demonstrated that restoration of nitrogenase activity in a UV-B-treated culture occurred by fresh synthesis of nitrogenase polypeptide. Our findings suggest that estimation of nitrogenase activity in diazotrophic species may be used as a marker enzyme for assessing the impact of UV-B radiation. Received: 13 June 2002 / Accepted: 22 July 2002     

A Probabilistic Human Health Risk Assessment for Environmental Exposure to Dibutylphthalate

In the European Union, Directive 92/32/EC and EC Council Regulation (EC) 793/93 require the risk assessment of industrial chemicals. In this framework, it is agreed to characterise the level of “risk” by means of the deterministic quotient of exposure and effects parameters. Decision makers require that the uncertainty in the risk assessment be accounted for as explicitly as possible. Therefore, this paper intends to show the advantages and possibilities of a probabilistic human health risk assessment of an industrial chemical, dibutylphthalate (DBP). The risk assessment is based on non-cancer endpoints assumed to have a threshold for toxicity. This example risk assessment shows that a probabilistic risk assessment in the EU framework covering both the exposure and the effects assessment is feasible with currently available techniques. It shows the possibility of comparing the various uncertainties involved in a typical risk assessment, including the uncertainty in the exposure estimate, the uncertainty in the effect parameter, and the uncertainty in assessment factors used in the extrapolation from experimental animals to sensitive human beings. The analysis done did not confirm the reasonable worst-case character of the deterministic EU-assessment of DBP. Sensitivity analysis revealed the extrapolation procedure in the human effects assessment to be the main source of uncertainty. Since the probabilistic approach allows determination of the range of possible outcomes and their likelihood, it better informs both risk assessors and risk managers.     

Aerosol Inoculator for Exposure of Human Volunteers

The performance of an aerosol inoculator for human volunteers is described in tests that used the PR8 strain of type A influenza virus and sodium fluorescein as a physical tracer. Virus recovery from the aerosols was approximately 1% and was unaffected by such variables as prolonged aerosolization, total airflow, relative humidity, or method of sampling. The recovery of sodium fluorescein from the aerosol was approximately 12% and was influenced by total airflow rates and relative humidity. With this apparatus, it should be possible to deliver reasonably predictable and measurable doses of respiratory viruses to human subjects. The design makes it possible to dismantle the inoculator into its component parts to facilitate portability.     

DNA Damage Responses following Exposure to Modulated Radiation Fields

During the delivery of advanced radiotherapy treatment techniques modulated beams are utilised to increase dose conformity across the target volume. Recent investigations have highlighted differential cellular responses to modulated radiation fields particularly in areas outside the primary treatment field that cannot be accounted for by scattered dose alone. In the present study, we determined the DNA damage response within the normal human fibroblast AG0-1522B and the prostate cancer cell line DU-145 utilising the DNA damage assay. Cells plated in slide flasks were exposed to 1 Gy uniform or modulated radiation fields. Modulated fields were delivered by shielding 25%, 50% or 75% of the flask during irradiation. The average number of 53BP1 or γH2AX foci was measured in 2 mm intervals across the slide area. Following 30 minutes after modulated radiation field exposure an increase in the average number of foci out-of-field was observed when compared to non-irradiated controls. In-field, a non-uniform response was observed with a significant decrease in the average number of foci compared to uniformly irradiated cells. Following 24 hrs after exposure there is evidence for two populations of responding cells to bystander signals in-and out-of-field. There was no significant difference in DNA damage response between 25%, 50% or 75% modulated fields. The response was dependent on cellular secreted intercellular signalling as physical inhibition of intercellular communication abrogated the observed response. Elevated residual DNA damage observed within out-of-field regions decreased following addition of an inducible nitric oxide synthase inhibitor (Aminoguanidine). These data show, for the first time, differential DNA damage responses in-and out-of-field following modulated radiation field delivery. This study provides further evidence for a role of intercellular communication in mediating cellular radiobiological response to modulated radiation fields and may inform the refinement of existing radiobiological models for the optimization of advanced radiotherapy treatment plans.     

A Preliminary Risk Assessment of Human Exposure to Phycotoxins in Shellfish: A Review

Over the past few decades, phycotoxins, secondary metabolites produced by toxic phytoplankton, have seen an increase in their frequency, concentrations, and geographic distribution. As shellfish accumulate phycotoxins making them unfit for human consumption, they are considered as an important food safety issue. Thus, a consumer exposure assessment on phycotoxins is necessary. Exposure assessment requires two types of information: contamination and consumption data. Shellfish contamination data on major toxins encountered by at-risk populations (Domoic Acid group, Okadaic Acid group, and Saxitoxin group) have been reviewed. Consumption data have been reviewed for both general and potential high-consumer populations. Then, we undertook acute and chronic exposure assessments, combining available French contamination data and our own consumption data. Studies including exposure assessment were then reviewed. Lastly, risk characterization was undertaken. It can be concluded that both acute and chronic exposure to phycotoxins via shellfish consumption is a matter of concern, mainly for high consumers identified in this review (specific populations and shellfish harvesters). However, the results for risk characterization must be improved. There is a need for (i) toxicological data to establish a Tolerable Daily Intake; (ii) an assessment of consumption and contamination data, undertaken at the same time, so as to assess exposure.     

Morphometric Indices of Scots Pine Needle under Chronic Radiation Exposure

We have studied the morphometric indices of needles in Scots pine populations that grow in Bryansk oblast in sites with radioactive contamination long after the Chernobyl accident. The variability in needle weight and length, as well as the fluctuating asymmetry indices and occurrence of necroses and morphoses, were studied in four contaminated and two reference populations of Scots pine in 2011, 2013, and 2014. The exposure of needles in radioactively contaminated sites varied from 7 to 130 mGy/yr. We found brachyblasts with three needles in contaminated Scots pine populations; this morphosis was absent in the reference populations. A dependence of the occurrence of needles damaged by necrosis on the levels of radiation exposure in 2011 was found. However, it was statistically insignificant in other years. The length and weight of needles in contaminated populations differed from the control values; however, the dependence of these indices on the level of radiation exposure was not revealed in the studied range of doses. In 2011 and 2013, the index of fluctuating asymmetry in needle length exceeded the control levels in sites where the absorbed doses were 90 and 130 mGy; this index also tended to grow (statistically significantly in 2011) with an increase in the characteristics of radioactive contamination of the studied plots: the exposure dose rate and the specific activity of ⁹⁰Sr and ¹³⁷Cs in cones and of ¹³⁷Cs in the soil. Therefore, one can observe the consequences of chronic radiation exposure at the organismic level in populations of Scots pine (one of the most radiosensitive plant species) even 25 years after the accident. The data that we obtained in natural habitats confirm the international estimates, according to which the annual chronic radiation exposure of 100 mGy can be considered the limit of safe radiation exposure of natural populations according to morphological and ontogenetic parameters.     

Survival of Shewanella oneidensis MR-1 after UV Radiation Exposure

We systematically investigated the physiological response as well as DNA damage repair and damage tolerance in Shewanella oneidensis MR-1 following UVC, UVB, UVA, and solar light exposure. MR-1 showed the highest UVC sensitivity among Shewanella strains examined, with D₃₇ and D₁₀ values of 5.6 and 16.5% of Escherichia coli K-12 values. Stationary cells did not show an increased UVA resistance compared to exponential-phase cells; instead, they were more sensitive at high UVA dose. UVA-irradiated MR-1 survived better on tryptic soy agar than Luria-Bertani plates regardless of the growth stage. A 20% survival rate of MR-1 was observed following doses of 3.3 J of UVC m⁻², 568 J of UVB m⁻², 25 kJ of UVA m⁻², and 558 J of solar UVB m⁻², respectively. Photoreactivation conferred an increased survival rate to MR-1 of as much as 177- to 365-fold, 11- to 23-fold, and 3- to 10-fold following UVC, UVB, and solar light irradiation, respectively. A significant UV mutability to rifampin resistance was detected in both UVC- and UVB-treated samples, with the mutation frequency in the range of 10⁻⁵ to 10⁻⁶. Unlike in E. coli, the expression levels of the nucleotide excision repair (NER) component genes uvrA, uvrB, and uvrD were not damage inducible in MR-1. Complementation of Pseudomonas aeruginosa UA11079 (uvrA deficient) with uvrA of MR-1 increased the UVC survival of this strain by more than 3 orders of magnitude. Loss of damage inducibility of the NER system appears to contribute to the high sensitivity of this bacterium to UVR as well as to other DNA-damaging agents.