c-MYC is a radiosensitive locus in human breast cells

Ionising radiation is a potent human carcinogen. Epidemiological studies have shown that adolescent and young women are at increased risk of developing breast cancer following exposure to ionising radiation compared with older women, and that risk is dose-dependent. Although it is well understood which individuals are at risk of radiation-induced breast carcinogenesis, the molecular genetic mechanisms that underlie cell transformation are less clear. To identify genetic alterations potentially responsible for driving radiogenic breast transformation, we exposed the human breast epithelial cell line MCF-10A to fractionated doses of X-rays and examined the copy number and cytogenetic alterations. We identified numerous alterations of c-MYC that included high-level focal amplification associated with increased protein expression. c-MYC amplification was also observed in primary human mammary epithelial cells following exposure to radiation. We also demonstrate that the frequency and magnitude of c-MYC amplification and c-MYC protein expression is significantly higher in breast cancer with antecedent radiation exposure compared with breast cancer without a radiation aetiology. Our data also demonstrate extensive intratumor heterogeneity with respect to c-MYC copy number in radiogenic breast cancer, suggesting continuous evolution at this locus during disease development and progression. Taken together, these data identify c-MYC as a radiosensitive locus, implicating this oncogenic transcription factor in the aetiology of radiogenic breast cancer.

Predictors of psychological functioning in children with cancer: disposition and cumulative life stressors

OBJECTIVE

This study examined psychological functioning in children with a history of cancer and a matched sample of healthy peers, while exploring the roles of disposition and stressful life events.

METHOD

Participants were 255 children with a history of cancer and 101 demographically matched children (8-17 years). Children completed measures of depression, anxiety, and posttraumatic stress symptoms (PTSS); history of stressful life events; and dispositional factors, including optimism and a five-factor personality measure.

RESULTS

Children with cancer did not differ from peers with regard to depression and PTSS, but reported significantly lower anxiety. In hierarchical regressions, children's depression, anxiety, and PTSS scores were largely predicted by dispositional variables and, to a lesser extent, stressful life events, after controlling for demographics and health status.

CONCLUSION

Children's psychological functioning is predicted primarily by disposition, and secondarily by history of stressful life events, with health status (i.e., cancer versus control) accounting for minimal, and often non-significant variance in children's functioning. These findings further support that children with cancer are generally resilient, with factors predictive of their adjustment difficulties mirroring those of children without history of serious illness.

Posttraumatic stress and psychological growth in children with cancer: has the traumatic impact of cancer been overestimated?

PURPOSE

To examine posttraumatic stress disorder and posttraumatic stress symptoms (PTSD/PTSS) in children with cancer using methods that minimize focusing effects and allow for direct comparison to peers without a history of cancer.

PATIENTS AND METHODS

Children with cancer (n = 255) stratified by time since diagnosis, and demographically matched peers (n = 101) were assessed for PTSD using structured diagnostic interviews by both child and parent reports, and survey measures of PTSS and psychological benefit/growth by child report.

RESULTS

Cancer was identified as a traumatic event by 52.6% of children with cancer, declining to 23.8% in those ≥ 5 years from diagnosis. By diagnostic interview, 0.4% of children with cancer met criteria for current PTSD, and 2.8% met lifetime criteria by self-report. By parent report, 1.6% of children with cancer met current criteria and 5.9% met lifetime criteria for PTSD. These rates did not differ from controls (all Ps >.1). PTSS levels were descriptively lower in children with cancer but did not differ from controls when all were referring to their most traumatic event (P = .067). However, when referring specifically to cancer-related events, PTSS in the cancer group were significantly lower than in controls (P = .002). In contrast, perceived growth was significantly higher in the cancer group when referring to cancer (P < .001).

CONCLUSION

These findings suggest no evidence of increased PTSD or PTSS in youths with cancer. Although childhood cancer remains a significant and challenging event, these findings highlight the capacity of children to adjust, and even thrive, in the face of such challenge.

Cause-specific mortality by occupational skill level in Canada: a 16-year follow-up study

Introduction

Mortality data by occupation are not routinely available in Canada, so we analyzed census-linked data to examine cause-specific mortality rates across groups of occupations ranked by skill level.

Methods

A 15% sample of 1991 Canadian Census respondents aged 25 years or older was previously linked to 16 years of mortality data (1991–2006). The current analysis is based on 2.3 million people aged 25 to 64 years at cohort inception, among whom there were 164 332 deaths during the follow-up period. Occupations coded according to the National Occupation Classification were grouped into five skill levels. Age-standardized mortality rates (ASMRs), rate ratios (RRs), rate differences (RDs) and excess mortality were calculated by occupational skill level for various causes of death.

Results

ASMRs were clearly graded by skill level: they were highest among those employed in unskilled jobs (and those without an occupation) and lowest for those in professional occupations. All-cause RRs for men were 1.16, 1.40, 1.63 and 1.83 with decreasing occupational skill level compared with professionals. For women the gradient was less steep: 1.23, 1.24, 1.32 and 1.53. This gradient was present for most causes of death. Rate ratios comparing lowest to highest skill levels were greater than 2 for HIV/AIDS, diabetes mellitus, suicide and cancer of the cervix as well as for causes of death associated with tobacco use and excessive alcohol consumption.

Conclusion

Mortality gradients by occupational skill level were evident for most causes of death. These results provide detailed cause-specific baseline indicators not previously available for Canada.

Cause-specific mortality by occupational skill level in Canada: a 16-year follow-up study

INTRODUCTION

Mortality data by occupation are not routinely available in Canada, so we analyzed census-linked data to examine cause-specific mortality rates across groups of occupations ranked by skill level.

METHODS

A 15% sample of 1991 Canadian Census respondents aged 25 years or older was previously linked to 16 years of mortality data (1991-2006). The current analysis is based on 2.3 million people aged 25 to 64 years at cohort inception, among whom there were 164 332 deaths during the follow-up period. Occupations coded according to the National Occupation Classification were grouped into five skill levels. Age-standardized mortality rates (ASMRs), rate ratios (RRs), rate differences (RDs) and excess mortality were calculated by occupational skill level for various causes of death.

RESULTS

ASMRs were clearly graded by skill level: they were highest among those employed in unskilled jobs (and those without an occupation) and lowest for those in professional occupations. All-cause RRs for men were 1.16, 1.40, 1.63 and 1.83 with decreasing occupational skill level compared with professionals. For women the gradient was less steep: 1.23, 1.24, 1.32 and 1.53. This gradient was present for most causes of death. Rate ratios comparing lowest to highest skill levels were greater than 2 for HIV/AIDS, diabetes mellitus, suicide and cancer of the cervix as well as for causes of death associated with tobacco use and excessive alcohol consumption.

CONCLUSION

Mortality gradients by occupational skill level were evident for most causes of death. These results provide detailed cause-specific baseline indicators not previously available for Canada.

Abdominal aortic aneurysm imaging with 3-D ultrasound: 3-D-based maximum diameter measurement and volume quantification

The clinical reliability of 3-D ultrasound imaging (3-DUS) in quantification of abdominal aortic aneurysm (AAA) was evaluated. B-mode and 3-DUS images of AAAs were acquired for 42 patients. AAAs were segmented. A 3-D-based maximum diameter (Max3-D) and partial volume (Vol30) were defined and quantified. Comparisons between 2-D (Max2-D) and 3-D diameters and between orthogonal acquisitions were performed. Intra- and inter-observer reproducibility was evaluated. Intra- and inter-observer coefficients of repeatability (CRs) were less than 5.18 mm for Max3-D. Intra-observer and inter-observer CRs were respectively less than 6.16 and 8.71 mL for Vol30. The mean of normalized errors of Vol30 was around 7%. Correlation between Max2-D and Max3-D was 0.988 (p < 0.0001). Max3-D and Vol30 were not influenced by a probe rotation of 90°. Use of 3-DUS to quantify AAA is a new approach in clinical practice. The present study proposed and evaluated dedicated parameters. Their reproducibility makes the technique clinically reliable.

[Time course of digital pressure during dialysis sessions in chronic hemodialysis patients. Prospective observational study of 49 patients]

OBJECTIVES

To describe and compare the evolution of digital pressure on both hands during a dialysis session in patients without digital ischemia, and to identify the parameters influencing the digital pressure.

MATERIALS

Patients with an upper limb vascular access were prospectively included. Digital systolic pressure on the third finger of both hands measured by photoplethysmography and brachial systolic pressure were recorded before dialysis (H0) and every hour (from H1 to H4).

RESULTS

Among 53 patients, 49 were included (exclusions: one surgery for ischemia, one hand tremor, two no consent). None of them had digital ischemia. Digital pressure homolateral to the vascular access was significantly lower compared with controlateral side before and during dialysis. Digital pressure significantly decreased on both sides during dialysis. Brachial pressure decreased significantly compared to H0. Only the brachial pressure decrease was correlated with the decrease of digital pressure. The digital pressure was less than 30 mmHg in six patients. No evidence of digital ischemia was reported after a 6-month follow-up.

CONCLUSION

To our knowledge, this is the first study showing a significant decrease of digital pressure in both hands during hemodialysis in patients without digital ischemia. Further studies are necessary to investigate which parameters can affect digital pressure and to look for clinical consequence of this measurement.

Integration of autophagy, proteasomal degradation, unfolded protein response and apoptosis

A single cell has the potential to kill an entire human being. Efforts to cure cancer are limited by survival of individual cancer cells despite immune surveillance and toxic therapies. Understanding the intricate network of pathways that maintain cellular homeostasis and mediate stress response or default into cell death is critical to the development of strategies to eradicate cancer. Autophagy, proteasomal degradation and the unfolded protein response (UPR) are cellular pathways that degrade and recycle excess or damaged proteins to maintain cellular homeostasis and survival. This review will discuss autophagy and how it is integrated with proteasomal degradation and UPR to govern cell fate through restoration of cellular homeostasis or default into the apoptotic cell death pathway. The first response of autophagy is macroautophagy, which sequesters cytoplasm including organelles inside double-membraned autophagosome vesicles that fuse with lysosomes to degrade and recycle the contents. Ubiquitination patterns on proteins targeted for degradation determine whether adapter proteins will bring them to developing autophagosomes or to proteasomes. Macroautophagy is followed by chaperone-mediated autophagy (CMA), in which Hsc70 (Heat shock cognate 70) selectively binds proteins with exposed KFERQ motifs and pushes them inside lysosomes through the LAMP-2A (Lysosome-associated membrane protein type 2A) receptor. These two processes and the lesser understood microautophagy, which involves direct engulfment of proteins into lysosomes, occur at basal and induced levels. Insufficient proteasome function or ER stress induction of UPR can induce autophagy, which can mitigate damage and stress. If this network is incapable of repairing the damage or overcoming continued stress, the default pathway of apoptosis is engaged to destroy the cell. Induction of macroautophagy by cancer therapeutics has led to clinical trials investigating combinations of HCQ (hydroxychloriquine) suppression of autophagy with apoptosis-inducing agents. Further study of the complex integration of autophagy, proteasomal degradation, UPR and apoptosis is likely to provide additional targets for our fight against cancer. This article is part of a Special Issue entitled "Apoptosis: Four Decades Later".

Advances in bile acid medicinal chemistry

Bile acids (BAs) are a family of steroidal molecules derived from cholesterol and biosynthesised in the pericentral hepatocytes of the liver. Structurally they may be regarded as consisting of two components, a rigid steroid nucleus and a short aliphatic side chain terminating in an alcohol or carboxyl group. Traditionally BAs are known for their ability to act as solubilising agents in the gut, aiding in the absorption of dietary lipids through the formation of mixed micelles. However the identification of BAs as ligands of the farnesoid X receptor (FXR) has lead to the realisation that these molecules have a wider range of biological effects. BAs regulate lipid and glucose homeostasis through activation of the FXR and the G-protein coupled receptor, TGR5. They can activate apoptotic, inflammatory and carcinogenic signalling pathways. BAs have also been shown to have anti-inflammatory effects. Interestingly, BAs are not restricted to the hepatic-intestinal system. Plasma BAs regulate BA synthesis and metabolism. BAs have recently been identified in cerebrospinal fluid. The BA, ursodeoxycholic acid has a potential role as a neuroprotectant in Huntington's disease and its taurine conjugate exhibits neuro-protective effects in vitro that may be relevant to Alzheimer's disease. This renaissance in BA biology has lead to the development of numerous medicinal chemistry programmes with different therapeutic targets, using BAs as lead structures. BA derivatives with increased efficacy and potency for FXR and TGR5 hold significant promise for the treatment of metabolic disorders. The peculiar effects of BAs on cell viability have been exploited for the design of selective cytocidal agents for treatment of various cancers. BA derivatives have also been screened with much success for anti-microbial and antifungal properties. Other targets include carbonic anhydrase for treatment of glaucoma and the glucocorticoid receptor for antiinflammatory effects. In this review interesting recent developments in the medicinal chemistry of these eclectic substances will be discussed.

Validation of diagnostic assays to screen broodstock for Flavobacterium psychrophilum infections

It is hypothesized that the frequency of bacterial coldwater disease outbreaks can be reduced through the detection of the aetiologic agent, Flavobacterium psychrophilum, in broodstock followed by culling of eggs from heavily infected broodstock. Before a culling programme can be instituted, however, it is necessary to determine the sensitivity and specificity of existing assays for the detection of F. psychrophilum. In this study, tissue and ovarian fluid samples were collected from 224 fish at five hatcheries and screened using an enzyme-linked immunosorbent assay (ELISA), a membrane-filtration fluorescent antibody test (MF-FAT), bacteriological culture and nested PCR. Latent class analysis was used to estimate sensitivity and specificity of kidney culture, kidney ELISA, nested PCR and MF-FAT. Analytical sensitivity of the ELISA varied but was greatest when bacteria were cultured under iron-limiting conditions. Diagnostic sensitivity estimates ranged from 0.02 (kidney culture) to 0.97 (kidney ELISA). Specificity estimates ranged from 0.02 (MF-FAT) to 0.98 (kidney ELISA). In a separate challenge experiment, the ELISA confirmed the presence of F. psychrophilum in sub-clinically infected fish. Results from this study demonstrate that the ELISA is an appropriate tool to screen broodstock and provides an indication of infection severity, which is crucial for implementation of a screening/culling programme.

Feedback on doctors' performance from parents and carers of children: a national pilot study

OBJECTIVES

To evaluate the reliability and validity of a children's carers' feedback tool, to explore the feasibility of delivering this nationally and to determine acceptability to doctors of this assessment.

PARTICIPANTS

122 UK paediatricians on the specialist register undertaking outpatient consultations.

DESIGN

Participants were each sent 50 forms for distribution to carers. Mean scores for each question, and for the overall pilot cohort were returned to participants with verbatim free text comments. Participating paediatricians' views were sought before and after receiving feedback.

RESULTS

122 doctors returned 4415 forms (mean 36 per doctor). All doctors scored highly with scores across all returned forms having a median of 4.58 (IQ range 0.17) where the maximum score was 5. Differences were observed between scores from female compared to male carers (p<0.05), from consultations rated by carer and child compared to carer alone (p<0.05) and from carers who had previously met the doctor compared to those in their first consultation (p<0.001). 'White' doctors received higher ratings than 'non-white' doctors (p<0.05) and white patients rated both white doctors and non-white doctors more highly than non-white patients (p<0.01). A minimum of 25 consultations rated by children's carers are needed for acceptable reliability. 93.9% of participants would be happy to be assessed in this way for the purposes of revalidation.

CONCLUSIONS

National delivery of a valid and reliable method of carer feedback is feasible. The scores received and acceptability in these self-selected doctors was high. Confounding variables may influence feedback, so guidance on interpretation may be needed.