Quantitative 3D elemental microtomography of Cyclotella meneghiniana at 400-nm resolution

X-ray fluorescence tomography promises to map elemental distributions in unstained and unfixed biological specimens in three dimensions at high resolution and sensitivity, offering unparalleled insight in medical, biological, and environmental sciences. X-ray fluorescence tomography of biological specimens has been viewed as impractical—and perhaps even impossible for routine application—due to the large time required for scanning tomography and significant radiation dose delivered to the specimen during the imaging process. Here, we demonstrate submicron resolution X-ray fluorescence tomography of a whole unstained biological specimen, quantifying three-dimensional distributions of the elements Si, P, S, Cl, K, Ca, Mn, Fe, Cu, and Zn in the freshwater diatom Cyclotella meneghiniana with 400-nm resolution, improving the spatial resolution by over an order of magnitude. The resulting maps faithfully reproduce cellular structure revealing unexpected patterns that may elucidate the role of metals in diatom biology and of diatoms in global element cycles. With anticipated improvements in data acquisition and detector sensitivity, such measurements could become routine in the near future.     

Influence of Age on the Association Between Various Measures of Obesity and All-Cause Mortality

OBJECTIVES: To determine whether the association between various simple measures of obesity and risk for all-cause mortality differs between younger and older men and women.
DESIGN: Prospective cohort study with 8.7 ± 0.2 years of follow-up for mortality linkage.
SETTING: Third National Health and Nutrition Examination Survey, 1988 to 1994.
PARTICIPANTS: Four thousand, four hundred thirty-seven men and 5,166 women.
MEASUREMENTS: Measures of obesity included body mass, waist circumference, waist-to-hip ratio, hip circumference, sum of skinfolds, and bioelectrical impedance.
RESULTS: Overall and abdominal obesity are associated with greater mortality risk in younger adults (<65) ( P <.05), whereas the associations between obesity and mortality are null or inverse in older adults (>65). In general, the association was stronger with measures of abdominal obesity than with measures of overall obesity or fat-free mass.
CONCLUSION: The adverse effects of obesity on mortality risk are apparent only in adults younger than 65. Obesity as characterized using several different measures was not generally associated with greater mortality risk in older adults. Although weight loss is beneficial for reducing morbidity in obese adults of any age, it is unclear whether weight loss is equally beneficial for reducing mortality risk in older adults.     

Multimodality Rodent Imaging Chambers for Use Under Barrier Conditions with Gas Anesthesia

Purpose  The ability to reproducibly and repeatedly image rodents in noninvasive imaging systems, such as small-animal positron emission tomography (PET) and computed tomography (CT), requires a reliable method for anesthetizing, positioning, and heating animals in a simple reproducible manner. In this paper, we demonstrate that mice and rats can be reproducibly and repeatedly imaged using an imaging chamber designed to be rigidly mounted on multiple imaging systems. Procedures  Mouse and rat imaging chambers were made of acrylic plastic and aluminum. MicroCT scans were used to evaluate the positioning reproducibility of the chambers in multimodality and longitudinal imaging studies. The ability of the chambers to maintain mouse and rat body temperatures while anesthetized with gas anesthesia was also evaluated. Results  Both the mouse and rat imaging chambers were able to reproducibly position the animals in the imaging systems with a small degree of error. Placement of the mouse in the mouse imaging chamber resulted in a mean distance of 0.23 mm per reference point in multimodality studies, whereas for longitudinal studies the mean difference was 1.11 mm. The rat chamber resulted in a mean difference of 0.46 mm in multimodality studies and a mean difference of 4.31 mm in longitudinal studies per reference point. The chambers maintained rodent body temperatures at the set point temperature of 38°C. Conclusions  The rodent imaging chambers were able to reproducibly position rodents in tomographs with a small degree of variability and were compatible with routine use. The embedded anesthetic line and heating system was capable of maintaining the rodent’s temperature and anesthetic state, thereby enhancing rodent health and improving data collection reliability.     

Towards quantifying the aesthetic outcomes of breast cancer treatment: comparison of clinical photography and colorimetry

Rationale, aims and objectives Scarring is a significant cause of dissatisfaction for women who undergo breast surgery. Scar tissue may be clinically distinguished from normal skin by aberrant colour, rough surface texture, increased thickness (hypertrophy) and firmness. Colorimeters or spectrophotometers can be used to quantitatively assess scar colour, but they require direct patient interaction and can cost thousands of dollars. By comparison, digital photography is already in widespread use to document clinical outcomes and requires less patient interaction. Thus, assessment of scar coloration by digital photography is an attractive alternative. The goal of this study was to compare colour measurements obtained by digital photography and colorimetry. Methods Agreements between photographic and colorimetric measurements of colour were evaluated. Experimental conditions were controlled by performing measurements on artificial scars created by a make‐up artist. The colorimetric measurements of the artificial scars were compared with those reported in the literature for real scars in order to confirm the validity of this approach. We assessed the agreement between the colorimetric and photographic measurements of colour using a hypothesis test for equivalence, the intraclass correlation coefficient and the Bland–Altman method. Results Overall, good agreement was obtained for three parameters (L*a*b*) measured by colorimetry and photography from the results of three statistical analyses. Conclusion Colour measurements obtained by digital photography were equivalent to those obtained using colorimetry. Thus, digital photography is a reliable, cost‐effective measurement method of skin colour and should be further investigated for quantitative analysis of surgical outcomes.