Structure-Function Relationships in Radiation-Induced Cell and Tissue Lesions: Special References to the Contributions of Scanning Electron Microscopy and Hematopoietic Tissue Responses

Contributions of scanning electron microscopy to the field of radiation biology are briefly reviewed and presented in terms of an overall goal to identify and characterize the structural features of radiation-induced lesions in vital cell and tissue targets. In the context of lesion production, the major radiation-elicited response sequences, the types and nature of measured end points, and governing temporal and radiobiological parameters are discussed and illustrated by using results derived from both in vitro cell systems and in vivo studies that measured tissue responses from various organ systems (respiratory, digestive, circulatory, and central nervous systems). Work in our laboratory on the nature of early and late hematopathologic tissue responses (aplastic anemia and myeloid leukemia) induced by protracted radiation exposure and the bridging effect of repair processes relative to the expression of these pathologies is highlighted

Alpha-Particle Irradiation-Induced Change in Bronchopulmonary Macrophage Morphology, In Vitro

Bronchopulmonary macrophages, isolated from canine lungs by saline lavage and grown in tissue culture for short periods, were acutely irradiated with a range of doses of either Americium-241 alpha particles (0.03-48 Gy) or 250 keV x-rays (0.5-24 Gy). Following a 24-hour reincubation and expression period, cells were examined for radiation-induced changes in overall viability, as well as in cell morphology and ultrastructure. Results indicated that neither quality of radiation had much effect on cell viability over dose ranges examined, but substantial changes in cell volume, surface topography, and cytoplasmic features were noted, especially in the alpha-particle-irradiated specimens. Results support the concept that the limiting plasma membrane of the targeted macrophage is a sensitive subcellular target for ionizing radiation, especially high-linear-energy-transfer heavy particles

SEM of Canine Chromosomes: Normal Structure and the Effects of Whole-Body Irradiation

Canine chromosomes are not only numerous (38 autosomal pairs), but they are small (compared to human chromosomes) and morphologically similar as well. Analysis of the canine karyotype by light microscopy (LM) of banded chromosomes is, thus, difficult, and the literature on the canine karyotype is scanty. In this study, we describe examination of chromosomes from normal and chronically irradiated dogs with the scanning elect ran microscope (SEM). Metaphase chromosomes from bone marrow aspirates were Giemsa-banded with either 0.025% trypsin alone or 0.1% trypsin preceded by 10% H2O2 and prepared for SEM. Examination of chromosomes from normal dogs revealed cylindrical chromosome profiles with well-defined chromatids and centromeres. The chromosome arms were consistently marked by periodic grooves that had complementary structures on sister chromatids and may represent the trypsin-sensitive chromatic regions. The quality of the preservation varied from preparation to preparation and depended on the concentration and time of trypsin treatment. Chromosomes from irradiated dogs revealed translocations, deletions, and gaps. We conclude that SEM produces images superior to LM images of canine chromosomes; SEM images can be used not only to identify individual chromosomes, but also to identify genetic lesions in the chromosomes of chronically irradiated dogs. We further conclude that the two Giemsa-banding protocols used in the present study produced variable results, although 0.025% trypsin alone appeared to give better and more consistent results than 0.1% trypsin preceded by 10% H2O2

Integrating food security into public health and provincial government departments in British Columbia, Canada

Food security policy, programs, and infrastructure have been incorporated into Public Health and other areas of the Provincial Government in British Columbia, including the adoption of food security as a Public Health Core Program. A policy analysis of the integration into Public Health is completed by merging findings from 48 key informant interviews conducted with government, civil society, and food supply chain representatives involved in the initiatives along with relevant documents and participant/direct observations. The paper then examines the results within the context of historic and international trends and theoretical models of food policy, community food security, and applied policy research. Public Health re-emerged as a driver of food security in BC—both as a key player and in positing the public’s health as a driver in food security and food systems. While Public Health’s lead role supported an increase in legitimacy for food security in BC, interviewees described a clash of cultures between Public Health and civil society. The clash of cultures occurred partly as a result of Public Health’s limited food security mandate and top down approach. Consequently civil society voice at the provincial level was marginalized. A social policy movement toward a new political paradigm—regulatory pluralism—calls for greater engagement of civil society, and for all sectors to work together toward common goals. A new, emerging policy map is proposed for analyzing the dynamics of food security and health promotion initiatives in BC

Clinical- and cost-effectiveness of a nurse led self-management intervention to reduce emergency visits by people with epilepsy

People with chronic epilepsy (PWE) often make costly, and clinically unnecessary emergency department (ED) visits. Some do it frequently. No studies have examined interventions to reduce them. An intervention delivered by an epilepsy nurse specialist (ENS) might reduce visits. The rationale is it may optimize patients' self-management skills and knowledge of appropriate ED use. We examined such an intervention's clinical- and cost-effectiveness. Eighty-five adults with epilepsy were recruited from three London EDs with similar catchment populations. Forty-one PWE recruited from two EDs received treatment-as-usual (TAU) and formed the comparison group. The remaining 44 PWE were recruited from the ED of a hospital that had implemented a new ENS service for PWE attending ED. These participants formed the intervention group. They were offered 2 one-to-one sessions with an ENS, plus TAU. Participants completed questionnaires on health service use and psychosocial well-being at baseline, 6- and 12-month follow-up. Covariates were identified and adjustments made. Sixty-nine (81%) participants were retained at follow-up. No significant effect of the intervention on ED visits at 12 months or on other outcomes was found. However, due to less time as inpatients, the average service cost for intervention participants over follow-up was less than for TAU participants' (adjusted difference £558, 95% CI, −£2409, £648). Covariates most predictive of subsequent ED visits were patients' baseline feelings of stigmatization due to epilepsy and low confidence in managing epilepsy. The intervention did not lead to a reduction in ED use, but did not cost more, partly because those receiving the intervention had shorter hospital admissions. Our findings on long-term ED predictors clarifies what causes ED use, and suggests that future interventions might focus more on patients' perceptions of stigma and on their confidence in managing epilepsy. If addressed, ED visits might be reduced and efficiency-savings generated

Maternal BMI and diabetes in pregnancy: Investigating variations between ethnic groups using routine maternity data from London, UK.

OBJECTIVE: To investigate the ethnicity-specific association between body mass index (BMI) and diabetes in pregnancy, with a focus on the appropriateness of using BMI cut-offs to identify pregnant women at risk of diabetes. STUDY DESIGN: Analysis of routinely-collected data from a maternity unit in London, UK. Data were available on 53 264 women delivering between 2004 and 2012. Logistic regression was used to explore the association between diabetes in pregnancy and BMI among women of different ethnicities, and adjusted probability estimates were used to derive risk equivalent cut-offs. ROC curve analysis was used to assess the performance of BMI as a predictor of diabetes in pregnancy. RESULTS: The prevalence of diabetes in pregnancy was 2.3% overall; highest in South and East Asian women (4.6% and 3.7%). In adjusted analysis, BMI category was strongly associated with diabetes in all ethnic groups. Modelled as a continuous variable with a quadratic term, BMI was an acceptable predictor of diabetes according to ROC curve analysis. Applying a BMI cut-off of 30 kg/m2 would identify just over half of Black women with diabetes in pregnancy, a third of White (32%) and South Asian (35%) women, but only 13% of East Asian women. The 'risk equivalent' (comparable to 30 kg/m2 in White women) threshold for South Asian and East Asian women was approximately 21 kg/m2, and 27.5 kg/m2 for Black women. CONCLUSIONS: This study suggests that current BMI thresholds are likely to be ineffective for diabetes screening in South and East Asian women, as many cases of diabetes will occur at low BMI levels. Our results suggest that East Asian women appear to face a similarly high risk of diabetes to South Asian women. Current UK guidelines recommend diabetes screening should be offered to all pregnant South Asian women; extending this recommendation to include women of East Asian ethnicity may be appropriate