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Iron is a nutritionally essential trace element known to affect physical and cognitive performance in military personnel. Previous studies indicate reductions in iron status in Soldiers ...during basic combat training (BCT). As the mechanism conferring declines in iron status during BCT has not been elucidated, the objective of this longitudinal study was to investigate the temporal effects of a 10‐week BCT course on indicators of iron status and serum hepcidin concentrations in male Soldiers. Blood biomarkers were assessed in fasted volunteers (n = 99, age mean ± SD = 23 ± 5 yrs) at four timepoints (wks 0, 3, 6, and 9) during BCT. Iron status declined during BCT, as serum ferritin, transferrin saturation, and hemoglobin levels decreased (P < 0.05), and soluble transferrin receptor levels increased (P < 0.05) at wk 9 as compared to wk 0. Serum hepcidin levels decreased (P < 0.05) from wk 0 to wk 6 (mean ± SEM 35.2 ± 2.5 vs. 31.1 ± 2.0 ng/mL) and increased (P < 0.05) from wk 6 to wk 9 (31.1 ± 2.0 vs. 37.4 ± 2.4). Temporal changes in serum hepcidin observed during BCT may have an affect on iron status, however future studies will be required to determine the direct relationship between serum hepcidin and declines in iron status during military training. Research supported by MRMC.
We introduce a model-based analysis technique for extracting and characterizing rhythmic expression profiles from genome-wide DNA microarray hybridization data. These patterns are clues to ...discovering rhythmic genes implicated in cell-cycle, circadian, or other biological processes. The algorithm, implemented in a program called RAGE (Rhythmic Analysis of Gene Expression), decouples the problems of estimating a pattern's wavelength and phase. Our algorithm is linear-time in frequency and phase resolution, an improvement over previous quadratic-time approaches. Unlike previous approaches, RAGE uses a true distance metric for measuring expression profile similarity, based on the Hausdorff distance. This results in better clustering of expression profiles for rhythmic analysis. The confidence of each frequency estimate is computed using Z-scores. We demonstrate that RAGE is superior to other techniques on synthetic and actual DNA microarray hybridization data. We also show how to replace the discretized phase search in our method with an exact (combinatorially precise) phase search, resulting in a faster algorithm with no complexity dependence on phase resolution.
Abstract
Listeria monocytogenes is a facultative anaerobic foodborne pathogen capable of surviving harsh environments. Recent work has indicated that anaerobic conditions increase the resistance ...capability of certain strains to environmental stressors. The goal of the study was to conduct a preliminary study to determine whether exposure to anaerobic conditions prior to infection increases the ability to survive in vivo. Gerbils were inoculated with one of five doses of the L. monocytogenes strain F2365 by oral gavage: phosphate-buffered saline (control), 5 × 106 colony forming units aerobic culture (low aerobic), 5 × 108 aerobic culture (high aerobic), 5 × 106 anaerobic culture (low anaerobic), or 5 × 108 anaerobic culture (high anaerobic) dose of F2365. Gerbils inoculated with a high aerobic or anaerobic dose exhibited significant weight loss. Gerbils administered either the low or high anaerobic dose had at least 3 log10 of L. monocytogenes present in fecal samples, which contrasted with gerbils that received the low aerobic dose. Animals that received the high anaerobic dose had a significant increase in bacterial loads within the liver. Histologic examination of the L. monocytogenes positive livers exhibited locally extensive areas of hepatocellular necrosis, though the extent of this damage differed between treatment groups. Microbial community analysis of the cecum from gerbils infected with L. monocytogenes indicated that the abundance of Bacteroidales and Clostridiales increased and there was a decrease in the abundance of Spirochaetales. This study suggests that anaerobic conditions alter the localization pattern of L. monocytogenes within the gastrointestinal tract. These findings could relate to how different populations are more susceptible to listeriosis, as oxygen availability may differ within the gastrointestinal tract.
Studies in vitro and in vivo have shown that quantitative ultrasound (QUS) is a valid tool for the assessment of bone status. Current QUS methods using the transmission technique are limited to one ...peripheral bone site. A new system, Sunlight Omnisense (Omnisense, Sunlight Medical Ltd., Rehovot, Israel), measures speed of sound (SOS, in m/s) along the surface of the bone based on an axial transmission technique. The Omnisense can measure SOS at several anatomical sites. This study evaluated the SOS at different anatomical sites in a healthy population. A total of 334 adult women from three research centers in the USA and Canada with a mean (+/- SD) age of 48.8 (+/- 17.4) years were enrolled in this study. SOS was measured at the proximal third phalanx, distal one third radius, midshaft tibia, and fifth metatarsal. The mean SOS (+/- SD) values for the phalanx, radius, tibia and metatarsal were 3984 (+/- 221), 4087 (+/- 147), 3893 (+/- 150) and 3690 (+/- 246) m/s, respectively. Each anatomical site SOS was significantly different (p < 0.001) from that of the other sites. SOS at the different anatomical sites was modestly, but significantly, correlated (r = 0.31 to 0.56, p < 0.001). Similar correlation coefficients were obtained for the T scores. The mean T scores for subjects over the age of 60 years were -1.94, -2.01, -0.97 and -1.42 for the phalanx, radius, tibia and metatarsal, respectively. The age of peak SOS and the rate of change thereafter varied with anatomical site, implying that the prevalence of osteopenia and osteoporosis was site-dependent if only one T score cut-off point was used. Comparing individuals, 10% to 17% of patients had T scores that differed by more than a factor of 2 between sites. Weight and age were some of the contributing factors to this heterogeneity. The Omnisense provides an opportunity to assess bone status at different anatomical sites. Whether or not combining measurements from all these anatomical sites will improve osteoporosis management still needs to be determined.
Iron is a nutritionally essential trace element known to affect physical and cognitive performance. Previous studies indicate a significant reduction in iron status in female Soldiers immediately ...following basic combat training (BCT). As iron status has not been assessed in male Soldiers during military training, the objective of this study was to investigate the longitudinal effects of a 10‐week BCT course on dietary iron intake and iron status indicators in male Soldiers. Iron status indicators were assessed in blood from fasted volunteers (n = 100, age mean ± SD = 23.0 ± 5.3 yrs) at four timepoints during BCT. Dietary iron intake was assessed using food frequency questionnaires pre‐ and post‐BCT. Despite increased iron intake (13.5 ± 0.9 pre‐BCT vs. 18.7 ± 1.0 mg/day post‐BCT, P < 0.05), iron status declined (P < 0.05) during BCT as demonstrated by reductions in serum ferritin (19.5 %), transferrin saturation (24.8 %), and hemoglobin (4.8 %). Future studies should assess the potential functional impact of declines in iron status in male Soldiers. Furthermore, the mechanism by which iron status declines during military training should be considered when developing countermeasures to prevent diminished iron status. Research supported by MRMC.
The mitotic spindle is a macromolecular structure utilized to properly align and segregate sister chromatids to two daughter cells. During mitosis the spindle maintains a constant length, even though ...the spindle microtubules (MTs) are constantly undergoing polymerization and depolymerization
1
. Members of the Kinesin-8 family are important for the regulation of spindle length and for chromosome positioning
2
–
9
. Kinesin-8 proteins are length specific, plus-end directed motors that are proposed to be either MT depolymerases
3
,
4
,
8
,
10
,
11
or MT capping proteins
12
. How Kif18A uses its destabilization activity to control spindle morphology is not known. We found that Kif18A controls spindle length independently of its role in chromosome positioning. The ability of Kif18A to control spindle length is mediated by an ATP-independent MT binding site at the C-terminal end of the Kif18A tail that has a strong affinity for MTs
in vitro
and in cells. We used computational modeling to ask how modulating the motility or binding properties of Kif18A would affect its activity. Our modeling predicts that both fast motility and a low off-rate from the MT end are important for Kif18A function. In addition our studies provide new insight into how depolymerizing and capping enzymes can lead to MT destabilization.
Kin Is, kinesins with an internal catalytic domain, de-polymerize microtubules from both ends, and the KIF2C crystal structure presented by
Ogawa et al. (2004)(this issue of
Cell) provides ...provocative evidence to support the theory that the highly conserved sequences are critical structural elements in these catastrophic kinesins.
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