Pursuing Cardiac Progenitors: Regeneration Redux

Recent studies have questioned the accepted dogma that the regenerative capacity of the heart following injury is limited. Several apparently distinct populations of resident cardiac progenitor cells may have the potential to regenerate functional heart muscle. Despite this progress, the physiologic role and therapeutic potential of cardiac resident progenitor cells remain unclear

Concentrations of Polychlorinated Biphenyls (PCB’s), Chlorinated Pesticides, and Heavy Metals and Other Elements in Tissues of Belugas, Delphinapterus leucas, from Cook Inlet

Tissues from Cook Inlet beluga whales, Delphinapterus leucas, that were collected as part of the Alaska Marine Mammal Tissue Archival Project were analyzed for polychlorinated biphenyls (PCB’s), chlorinated pesticides, and heavy metals and other elements. Concentrations of total PCB’s (ΣPCB’s), total DDT (ΣDDT), chlordane compounds, hexachlorobenzene (HCB), dieldrin, mirex, toxaphene, and hexachlorocyclohexane (HCH) measured in Cook Inlet beluga blubber were compared with those reported for belugas from two Arctic Alaska locations (Point Hope and Point Lay), Greenland, Arctic Canada, and the highly contaminated stock from the St. Lawrence estuary in eastern Canada. The Arctic and Cook Inlet belugas had much lower concentrations (ΣPCB’s and ΣDDT were an order of magnitude lower) than those found in animals from the St. Lawrence estuary. The Cook Inlet belugas had the lowest concentrations of all (ΣPCB’s aver-aged 1.49 ± 0.70 and 0.79 ± 0.56 mg/kg wet mass, and ΣDDT averaged 1.35 ± 0.73 and 0.59 ± 0.45 mg/kg in males and females, respectively). Concentrations in the blubber of the Cook Inlet males were significantly lower than those found in the males of the Arctic Alaska belugas (ΣPCB’s and ΣDDT were about half). The lower levels in the Cook Inlet animals might be due to differences in contaminant sources, food web differences, or different age distributions among the animals sampled. Cook Inlet males had higher mean and median concentrations than did females, a result attributable to the transfer of these compounds from mother to calf during pregnancy and during lactation. Liver concentrations of cadmium and mercury were lower in the Cook Inlet belugas (most cadmium values were <1 mg/kg and mercury values were 0.704–11.42 mg/kg wet mass), but copper levels were significantly higher in the Cook Inlet animals (3.97–123.8 mg/kg wet mass) than in Arctic Alaska animals and similar to those reported for belugas from Hudson Bay. Although total mercury levels were the lowest in the Cook Inlet population, methylmercury concentrations were similar among all three groups of the Alaska animals examined (0.34–2.11 mg/kg wet mass). As has been reported for the Point Hope and Point Lay belugas, hepatic concentrations of silver were r

Deuteronomy and Numbers

Four light isotopes - D, ^3He, ^4He and ^7Li - were produced by nuclear reactions a few seconds after the big bang. New measurements of ^3He in the ISM by Gloeckler and Geiss and of deuterium in high redshift hydrogen clouds by Tytler and his collaborators provide further confirmation of big-bang nucleosynthesis and new insight about the density of ordinary matter (baryons).Comment: 6 pages LaTeX with 1 eps Figur

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Contains research objectives and reports on five research projects

Discordant Population Structure Among Rhizobium Divided Genomes and Their Legume Hosts

Symbiosis often occurs between partners with distinct life history characteristics and dispersal mechanisms. Many bacterial symbionts have genomes comprising multiple replicons with distinct rates of evolution and horizontal transmission. Such differences might drive differences in population structure between hosts and symbionts and among the elements of the divided genomes of bacterial symbionts. These differences might, in turn, shape the evolution of symbiotic interactions and bacterial evolution. Here we use whole genome resequencing of a hierarchically structured sample of 191 strains of Sinorhizobium meliloti collected from 21 locations in southern Europe to characterize population structures of this bacterial symbiont, which forms a root nodule symbiosis with the host plant Medicago truncatula. S. meliloti genomes showed high local (within-site) variation and little isolation by distance. This was particularly true for the two symbiosis elements, pSymA and pSymB, which have population structures that are similar to each other, but distinct from both the bacterial chromosome and the host plant. Given limited recombination on the chromosome, compared to the symbiosis elements, distinct population structures may result from differences in effective gene flow. Alternatively, positive or purifying selection, with little recombination, may explain distinct geographical patterns at the chromosome. Discordant population structure between hosts and symbionts indicates that geographically and genetically distinct host populations in different parts of the range might interact with genetically similar symbionts, potentially minimizing local specialization

Students at Enrollment Into CommunityBased Systems of Care: Characteristics and Predictors of Functioning in School

Community-based systems of care (SOC) provide a range of services to students with significant emotional and behavioral difficulties and their families. However, little is known about the educational characteristics and functioning of students at enrollment in SOC. The purpose of this study was to replicate and extend previous research by examining the educational characteristics and predictors of school functioning for students referred to SOC using a large and diverse national data source. Participants were 5,628 students ages 6 to 18 years who were enrolled in community-based SOC across 45 U.S. states, districts, and territories. Students’ grades, discipline, and attendance (as reported by caregivers) were used as indicators of school functioning, and students’ demographic characteristics, referral source, and emotional/behavioral functioning were used to predict functioning in school, including the testing of interaction effects. Findings revealed that, although many students earned average grades, a large portion of students had significant discipline and attendance problems. Results of the ordinal regression analyses indicated that most demographic variables and measures of clinical functioning significantly predicted students’ grades, attendance, and discipline, and that age and special education status represented a significant interaction. Findings provide insight into the educational functioning of students at enrollment in community-based SOC and have implications for research and practice

Strong partnerships make good partners: Insights about physician-hospital relationships from a study of physician executives

While physicians are likely to respond favorably in concept to hospital-based disease management and other clinical programs, they are less likely to accept their structural and functional characteristics. Because of their role at the hospital-physician interface, hospital physician executives are often tasked with implementing such programs. Given the challenges involved, a deeper understanding of the role of these executives in building the hospital-physician relationship will therefore be an important contribution. To this end, we surveyed senior physician executives at hospitals and health systems (n = 326), to assess their view of the hospital-physician relationship at their institutions, focusing especially on the role of medical staff cohesion. This article presents several of our key findings, in particular that (1) many physician executives identified their medical staff as having relatively low cohesion and (2) the perceived level of medical staff cohesion correlated strongly with the level of physician support for organizational priorities, the degree of constructive physician involvement, and success in improving the physician-hospital relationship. In light of these findings, we conclude by offering concrete recommendations for physician executives and others seeking to build medical staff cohesion in the service of clinical improvement

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Contains research objectives and reports on four research projects.Lincoln Laboratory, Purchase Order DDL-B222Department of the ArmyDepartment of the NavyDepartment of the Air Force under Contract AF19(122)-45