Perceptions and experiences of environmental health risks among new mothers: a qualitative study in Ontario, Canada

There is a growing awareness and concern in contemporary societies about potential health impacts of environmental contaminants on children. Mothers are traditionally more involved than other family members in managing family health and household decisions and thus targeted by public health campaigns to minimise risks. However little is known about how new mothers perceive and experience environmental health risks to their children. In 2010, we undertook a parallel case study using qualitative, in-depth interviews with new mothers and focus groups with public health key informants in two Public Health Units in Ontario Province, Canada. We found that the concern about environmental hazards among participants ranged from having no concerns to actively incorporating prevention into daily life. Overall, there was a common perception among participants that many risks, particularly in the indoor environment, were controllable and therefore of little concern. But environmental risks that originate outside the home were viewed as less controllable and more threatening. In response to such threats, mothers invoked coping strategies such as relying on the capacity of children's bodies to adapt. Regardless of the strategies adopted, actions (or inactions) were contingent upon active information seeking. We also found an optimistic bias in which new mothers reported that other children were at greater risk despite similar environmental circumstances. The findings suggest that risk communication experts must attend to the social and environmental contexts of risk and coping when designing strategies around risk reducing behaviours.

Molecular characterization of neuroendocrine lung-tumors induced in hamsters by treatment with nitrosamines and hyperoxia

Treatment of hamsters with nitrosamines and hyperoxia (60% O2) induces neuroendocrine lung tumors. Analysis of 8 different tumors from 7 different hamsters demonstrated 2- to 3.5-fold increases in the expression of c-myc in 4 of 8 tumors, c-fos in 3 tumors, c-jun in 1 tumor, c-raf in 1 tumor, and Ki-ras in 2 tumors. No overexpression of the c-src and Ha-ras gene transcripts were detected. Expression levels of N-myc, p53 and the retinoblastoma gene transcript were too low to be quantitated accurately. In some cases, slightly elevated levels of protooncogene transcripts (less than 2-fold) were detected in normal-appearing tissue isolated from the same tumor bearing hamsters. Hyperoxia alone had little effect on the expression of c-myc or c-fos RNA transcripts compared to untreated hamsters. Reverse transcription of the RNAs and amplification of the cDNA copies by the polymerase chain reaction, followed by selective oligonucleotide hybridization with normal and mutant probes, did not reveal any mutations in the 12th, 13th, or 61st codons of the seven tumors which produced Ki-ras cDNA. An additional 8 tumors were also screened for Ki-ras mutations following amplification of genomic DNA and demonstrated an absence of point mutations at the Ki-ras gene locus. These results indicate that the hamster neuroendocrine lung tumors exhibit slight increases in c-myc and c-fos RNA expression but lack mutations at the Ki-ras gene locus.

Time use differences in activity participation among children 4-5 years old with and without the risk of developing conduct problems

Conduct problems in childhood are associated with the way in which children engage in daily activities. Research, to date, on conduct problems in relation to time use has primarily focused on school aged children and their participation in discrete activities such as watching TV and sport. The purpose of the present study is to determine if children at risk of developing conduct problems have different activity patterns compared to those not at risk. Specifically aspects of time use which concern involvement in activities that provide physical exertion, structure, rest and social engagement were examined. Data for this investigation were drawn from the Longitudinal Study of Australian Children (Wave 1) and focused on 4936 children aged 4-5 years. Findings indicate that children at risk of developing conduct problems spend significantly more time in: physical activities such as "riding a bike", and "in the company of adults only" than children not at risk of developing conduct problems but less time "with peers under adult supervision". Gender differences were also found in the same activities with boys participating in more "bike riding" and activities "without peers under adult supervision" than girls. Young children generally participated in more physical activities and spend more time "with peers while supervised by adults" on weekend days, and more time in "structured activities" and "in the company of adults only" on weekdays. These findings are discussed in respect of the potentially risky nature of physical activity choice and the contribution of adult supervision in the context of peer group participation for children at risk of developing conduct problems.

Positive supercoiling of mitotic DNA drives decatenation by topoisomerase II in eukaryotes

DNA topoisomerase II completely removes DNA intertwining, or catenation, between sister chromatids before they are segregated during cell division. How this occurs throughout the genome is poorly understood. We demonstrate that in yeast, centromeric plasmids undergo a dramatic change in their topology as the cells pass through mitosis. This change is characterized by positive supercoiling of the DNA and requires mitotic spindles and the condensin factor Smc2. When mitotic positive supercoiling occurs on decatenated DNA, it is rapidly relaxed by topoisomerase II. However, when positive supercoiling takes place in catenated plasmid, topoisomerase II activity is directed toward decatenation of the molecules before relaxation. Thus, a topological change on DNA drives topoisomerase II to decatenate molecules during mitosis, potentially driving the full decatenation of the genome.

Time use, parenting practice and conduct problems in four- to five-year-old Australian children

BACKGROUND

Conduct problems (CoP) represent one of the most common mental health issues manifesting in childhood, with the potential to influence the developmental trajectory of children negatively. Early identification of children at risk of developing CoP is a key strategy to their effective management. Evidence suggests that parenting practices are important contributors to CoP; however, these practices can also interact with the activities in which children engage and these have not yet been addressed in combination.

METHOD

A cross-sectional study of a nationally representative sample of 4936 four- to five-year-old children from Wave 1 of the Longitudinal Study of Australian Children was undertaken to examine the relationship between CoP, parenting practices and time use.

RESULTS

All children were at a lower risk of CoP if they were exposed to less hostile and consistent parenting practices and if they did not have sleep problems as reported by their parents. However, boys were more vulnerable if they had fathers who had not undertaken tertiary education, and spent more time in risk-oriented physical activities.

CONCLUSION

Parenting practices are affirmed as a significant independent predictor of risk for developing CoP. The nature of activities in which children engaged, particularly boys, also has the potential to influence the manifestation of CoP. Occupational therapy services for children with CoP are best provided in the context of family-centred practice and should incorporate an examination of daily time use.

Physical linkages between sister chromatids and their removal during yeast chromosome segregation

The fidelity of chromosome inheritance is of paramount importance to all living organisms. In eukaryotic cells, the strategy to ensure physical segregation of chromosomes to daughter cells relies on two basic steps ordered in time: an initial linkage, or cohesion, of sister chromatids and its timely and complete dissolution during anaphase. The current view is that these two basic steps are accomplished around the regulation of a protein complex called cohesin that serves as "clamp brackets" distributed at intervals throughout the genome. However, many of the DNA metabolic activities during interphase also produce physical linking of chromatids. For example, during replication, intertwines between sister chromatids are formed. Here, we review our understanding of the processes that generate physical linkages between chromatids and discuss potential mechanisms that are involved in the removal of such obstacles to the complete physical separation of chromatids at anaphase.

Does having a chronic physical condition affect the likelihood of treatment seeking for a mental health problem and does this vary by ethnicity?

OBJECTIVE

The comorbidity of mental disorders with chronic physical conditions is known to have important clinical consequences, but it is not known whether mental-physical comorbidity influences mental health treatment seeking. This study investigates whether the presence of a chronic physical condition influences the likelihood of seeking treatment for a mental health problem, and whether that varies among ethnic subgroups in New Zealand.

METHODS

Analyses were based on a subsample (n = 7,435) of The New Zealand Mental Health Survey, a nationally representative household survey of adults (response rate 73.3%). Ethnic subgroups (Maori and Pacific peoples) were oversampled. DSM-IV mental disorders were measured face-to-face with the Composite International Diagnostic Interview (CIDI 3.0). Ascertainment of chronic physical conditions was via self-report.

RESULTS

In the general population, having a chronic medical condition increased the likelihood of seeking mental health treatment from a general practitioner (OR: 1.58), as did having a chronic pain condition (OR: 2.03). Comorbid chronic medical conditions increased the likelihood of seeking mental health treatment most strongly among Pacific peoples (ORs: 2.86-4.23), despite their being less likely (relative to other ethnic groups) to seek mental health treatment in the absence of physical condition comorbidity.

CONCLUSION

In this first investigation of this topic, this study finds that chronic physical condition comorbidity increases the likelihood of seeking treatment for mental health problems. This provides reassurance to clinicians and health service planners that the difficult clinical problem of mental-physical comorbidity is not further compounded by the comorbidity itself constituting a barrier to mental health treatment seeking.

Linear and nonlinear characteristics of heart rate time series in obesity and during weight-reduction surgery

Obesity is associated with abnormal cardiac regulation by the autonomic nervous system (ANS), this being reversed by weight loss. Bariatric (weight-reduction) surgery can induce substantial long-term weight reductions. This study compares the acute influence on ANS control of two different types of bariatric surgery involving laparascopic and open procedures. To distinguish between the cardiac influences of surgery and obesity, we perform the same analysis for laparascopic surgery in non-obese patients. Eight morbidly obese and five non-obese patients underwent surgery. Obese patients received either laparoscopic procedures (group A: n = 5, BMI = 44.3 +/- 2.7 kg m(2)) or open procedures (group B: n = 3, BMI = 55.2 +/- 4.5 kg m(2)) and non-obese patients received a laparoscopic procedure (group C: n = 5, BMI = 30.8 +/- 5.8 kg m(-2)). Holter ECG was recorded and heart rate variability (HRV) was quantified together with measures of complexity (sample entropy) and structure (Hurst coefficient, scaling coefficient) of the heart rate data. Multifractal characteristics of heart rate data, not previously reported for obese patients, are also quantified and interpreted. Mixed model ANOVA was used to assess the magnitudes of each quantified variable, with surgical group and perioperative time as main factors. HRV measures were influenced only during anaesthesia (LFn increase: p = 0.009; HFn decrease: p = 0.033) and did not discriminate between patient groups. Multifractality was the only characteristic of heart rate data that discriminated between patient groups, being significantly (p < 0.001) greater in non-obese (group C) compared with obese patients (groups A and B, who had similar multifractal properties). Multifractality was also enhanced during anaesthesia (p = 0.028) but did not differ for other stages. We conclude that obesity per se rather than response to surgery is the cause of reduced multifractality. Reduced multifractality in obesity might reflect a diminished 'scaling' or 'collective response' across the multiple autonomic modulators of heart rate. The multifractal method appears to be a more sensitive measure of integrated cardiac autonomic function than linear methods for these patients.

Imatinib sensitivity as a consequence of a CSF1R-Y571D mutation and CSF1/CSF1R signaling abnormalities in the cell line GDM1

Imatinib is usually a highly effective treatment for myeloproliferative neoplasms (MPNs) associated with ABL, PDGFRA or PDGFRB gene fusions; however, occasional imatinib-responsive patients have been reported without abnormalities of these genes. To identify novel imatinib-sensitive lesions, we screened 11 BCR-ABL-negative cell lines and identified GDM1, derived from a patient with an atypical MPN (aMPN), as being responsive to imatinib. Screening of genes encoding known imatinib targets revealed an exon 12 mutation in the colony-stimulating factor 1 receptor (CSF1R; c-FMS) with a predicted Y571D amino-acid substitution. CSF1R in GDM1 was constitutively phosphorylated, but rapidly dephosphorylated on exposure to imatinib. Y571D did not transform FDCP1 cells to growth factor independence, but resulted in a significantly increased colony growth compared with controls, constitutive CSF1R phosphorylation and elevated CSF1R signaling. We found that GDM1 expresses CSF1, and CSF1 neutralization partially inhibited proliferation, suggesting the importance of both autocrine and intrinsic mechanisms of CSF1R activation. An extensive screen of CSF1R in aMPNs and acute myeloid leukemia identified three additional novel missense variants. None of these variants were active in transformation assays and are therefore likely to be previously unreported rare polymorphisms or non-pathogenic passenger mutations.

A randomized comparison of two instruments for measuring self-reported antiretroviral adherence

A randomised trial compared two instruments for assessing self-reported adherence to antiretroviral medications: (1) a day-by-day recall instrument that elicited the number of missed doses in each of the prior three days (3-day instrument; n=64) and (2) a general recall instrument that elicited an estimate of proportion of pills taken during the prior seven days (7-day instrument; n=70). Adherence was measured at study visits over 12 months among participants in a clinical trial assessing treatment strategies for individuals with virologic failure and multidrug-resistant HIV. Participants had a median (interquartile range) of 133 (41-264) CD4 cells/ml(3) and a median of 10 major HIV resistance mutations at baseline. Mean adherence levels were 90-98% throughout the study. There was a greater trend in the likelihood of 100% adherence when measured by the 3-day versus the 7-day instrument (odds ratio (OR)=1.45; p=0.06). The likelihood of consistent 100% adherence measured by either instrument decreased over time (p<0.001). Participants reporting 100% adherence at more than half of study visits had better virologic and immunologic outcomes at month-12 compared to those reporting 100% adherence at half or fewer visits (HIV RNA decline of 0.96 versus 0.51 log, respectively, p=0.02; and CD4 cell increase of 51.0 versus 17.8 cells, p=0.04). This study demonstrated the utility of the general 7-day recall adherence self-report instrument as well as the 3-day day-by-day recall adherence self-report instrument for measuring antiretroviral adherence. Self-reported adherence was significantly associated with virologic and immunologic outcomes in this population with advanced drug-resistant HIV disease.