A search for apatite crystals in the gap zone of collagen fibrils in bone using dark-field illumination.

Bright-field transmission electron microscope (TEM) images of ion milled or focused ion beam (FIB) sections of cortical bone sectioned parallel to the long axis of collagen fibrils display an electron-dense phase in the gap zones of the fibrils, as well as elongated plates (termed mineral lamellae) comprised of apatite crystals, which surround and lie between the fibrils. Energy dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) studies by others have shown that the material in the gap zones is calcium phosphate. Dark-field (DF) images are capable of revealing the projected position of crystals of apatite in a section of bone. We obtained bright field (BF) images of ion milled sections of bovine femoral cortical bone cut parallel to fibril axes (longitudinal view), and compared them with DF images obtained using the (002) apatite reflection to test a widely held theory that most of the mineral in bone resides in the gap zones. Most apatite crystals which were illuminated in DF images and which projected onto gap zones were extensions of crystals that also project onto adjacent overlap zones. However, in BF images, overlap zones do not appear to contain significant amounts of mineral, implying that the crystals imaged in DF are actually in the interfibrillar matrix but projected onto images of fibrils. However a small number of "free" illuminated crystals did not extend into the overlap zones; these could be physically located inside the gap zones. We note that projections of gap zones cover 60% of the area of any longitudinal field of view; thus these "free" crystals have a high random probability of appearing to lie on a gap zone, wherever they physically lie in the section. The evidence of this study does not support the notion that most of the mineral of bone consists of crystals in the gap zone. This study leaves uncertain what is the Ca-P containing material present in gap zones; a possible candidate material is amorphous calcium phosphate.

Increasing the fruit and vegetable consumption of fourth-graders: results from the high 5 project.

BACKGROUND: This study evaluated the effects of a school-based dietary intervention program to increase fruit and vegetable consumption among fourth-graders. METHODS: Twenty-eight elementary schools were randomized to an immediate intervention condition or to a delayed intervention control condition. Measures of diet and psychosocial variables were collected at base line and 1 and 2 years post-baseline. The intervention included classroom, parent, and cafeteria components. RESULTS: Mean daily consumption of fruit and vegetables was higher for the intervention children compared with controls at Follow-up 1 (X(t) = 3.96, X(c) = 2.28) and at Follow-up 2 (X(t) = 3.20, X(c) = 2.21). Macro- and micronutrient changes favoring the intervention children were also observed at both Follow-up 1 and Follow-up 2. Mean daily consumption of fruit and vegetables was higher for intervention parents compared with controls at Follow-up 1 (X(t) = 4.23,X(c) = 3.94) but not at Follow-up 2. CONCLUSIONS: Strong effects were found for the High 5 intervention on fruit and vegetable consumption, on macro- and micro-nutrients, and on psychosocial variables. Future work is needed to enhance the intervention effects on parents' consumption and to test the effectiveness of the intervention when delivered by classroom teachers.

Patterns in child and adolescent consumption of fruit and vegetables: effects of gender and ethnicity across four sites.

OBJECTIVES: Few studies have examined the association of gender and ethnicity with fruit and vegetable consumption. We examined these associations using baseline data from four school-based sites funded under the National Cancer Institute's 5 A Day for Better Health Program. METHODS: Diet was measured using 24-hour recalls at three sites and seven-day food records at one site. Demographics were obtained via self-report or school records. Regression analyses for clustered data were employed with fruit and vegetables combined and fruit and vegetables separately. RESULTS: Girls ate more fruit, more vegetables and more fruit and vegetables combined than boys at the Georgia site. Ethnicity was significant in two sites: In Georgia, African-Americans ate more fruit and more fruit and vegetables combined than European-Americans; in Minnesota, Asian-American/Pacific Islanders and African-Americans ate more fruit than European-Americans, and European-Americans and African-Americans ate more vegetables than Asian-Americans. No significant effects were found at the Alabama or Louisiana sites. CONCLUSIONS: Ethnicity was related to fruit and vegetable consumption in Georgia and Minnesota. Consistent with prior studies, gender was related to fruit and vegetable consumption, with girls consuming more servings than boys; however, this was observed at one site only, Georgia. Consumption levels were similar to national estimates for children and varied by region. Further studies are needed using a single methodology to facilitate regional comparisons.

Effect of Eucalyptus saligna and Albizia falcataria on soil processes and nitrogen supply in Hawaii.

This study investigated the differences between two fast-growing tropical tree species on soil N flux and availability. The work was conducted in the island of Hawaii and included three sites located along the Hamakua coast on the northeastern side of the island. Within each site pure stands of Eucalyptus saligna (Sm.)␣and the N2-fixing Albizia falcataria (L.) Fosberg [=Paraserianthes falcataria (L.) Nielsen] were arranged in four randomized complete blocks. For most of the variables considered in this study, the species effects were usually strong and the site effects were significant in some cases. After 13 years, soils under the Albizia stand contained larger pools of total soil C and N, and larger pools of inorganic N. Soil N availability indexed by ion exchange resin bags revealed a strong pattern of species and site effect on N availability; soils under Albizia showed a 2.6-9 fold increase in N availability (P < 0.01). Potential net rates of N transformation (10- and 30-day aerobic incubations) were more than twice as high for soils under the Albizia than under the Eucalytus stands. Nitrogen mineralization during anaerobic incubations were about 10% greater on Albizia soils. Gross microbial mineralization and immobilization were determined by estimating the gross rates of N transformation by the 15N-isotope pool dilution techniques. Across species and sites, a strong linear positive relationship was obtained for gross immobilization and gross mineralization indicating faster gross immobilization as gross mineralization increases. Soil microbial biomass on Albizia soils contained larger proportion of it as bacterial biomass, while larger proportion of fungi biomass comprised the microbial biomass under Eucalyptus soils. This study clearly showed that the presence of Albizia increased total N pools and N supply to the ecosystem. The overall effect on soil fertility will need to be characterized by the effect of the N2-fixer on other nutrients, especially the effect on phosphorus.

Design of "High 5": a school-based study to promote fruit and vegetable consumption for reduction of cancer risk.

BACKGROUND: This paper describes the methods used in "High 5," a school-based study to increase fruit and vegetable consumption for cancer risk reduction. METHODS: Twenty-eight elementary schools were matched and randomized to intervention or control conditions. All students were assessed based on diet and psychosocial variables at baseline and one and two years post-baseline. The intervention included classroom, parent, and environmental components. RESULTS: The study recruited 1,698 families and retained 85%. The two conditions were equivalent at baseline; 50% female students, 81% to 84% European-American students, and 2.9 servings of fruit and vegetables per day. Good completion was achieved across the intervention components (e.g., 90% of lessons taught, 72% of parent materials read, 3.6 servings of fruit and vegetables offered in cafeterias). CONCLUSIONS: The use of school-based programs, with strong evaluation designs, will enhance knowledge about the modification of nutrition behavior and cancer risk in children. Lessons learned from the study are reported.

Recruitment issues in school-based research: lessons learned from the High 5 Alabama Project.

School-based research requires a multi-level recruitment process to ensure an adequate sample. This article describes the High 5 Alabama recruitment experience at four levels; district, school, classroom and individual. One hundred percent of 28 schools across three districts and 108 classroom teachers contacted agreed to participate. Moderate success (69%) at the individual level, which required active parental consent for the student and parent to participate, resulted in 1,698 student/parent participants. An examination of differences between participants and nonparticipants revealed under-representation of a subsample of the population in the project sample. Suggestions obtained from project staff and teachers intended to enhance future school-based recruitment strategies include enlistment of a district advocate; meeting with teachers to solicit support; using incentives with students and teachers; direct contact with parents; having teachers keep rosters of students returning consent forms; and tailoring recruitment strategies for specific subpopulations.

Pharmacists as HIV/AIDS information resources: survey of Alabama pharmacists.

Alabama pharmacists were surveyed by researchers from the University of Alabama at Birmingham's School of Public Health in collaboration with investigators at the Schools of Pharmacy at Auburn University and Stamford University as part of a statewide pharmacists' demonstration project to mobilize pharmacists and pharmacy locations as information resources for HIV/AIDS education and prevention. The objectives of the survey were to: (1) establish a baseline of knowledge and attitudes among Alabama pharmacists about HIV/AIDS; (2) to assess Alabama pharmacists' willingness to assume the role of HIV/AIDS information resources in their communities; and (3) to identify perceived barriers to assuming the role of information resources. The results of the survey were used in the development of an educational intervention program and will be used subsequently to assess the impact of the implementation of the Alabama demonstration project. Findings from this project will serve as a basis for development of a nationwide project as part of a collaborative agreement between the Centers for Disease Control and Prevention's National Partnership Program and the Foundation of Pharmacists and Corporate America for AIDS Education.

Attributes of reliable long-term landscape-scale studies: Malpractice insurance for landscape ecologists.

Monitoring long-term change in forested landscapes is an intimidating challenge with considerable practical, methodological, and theoretical limitations. Current field approaches used to assess vegetation change at the plot-to-stand scales and nationwide forest monitoring programs may not be appropriate at landscape scales. We emphasize that few vegetation monitoring programs (and, thus, study design models) are designed to detect spatial and temporal trends at landscape scales. Based primarily on advice from many sources, and trial and error, we identify 14 attributes of a reliable long-term landscape monitoring program: malpractice insurance for landscape ecologists. The attributes are to: secure long-term funding and commitment; develop flexible goals; refine objectives; pay adequate attention to information management; take an experimental approach to sampling design; obtain peer-review and statistical review of research proposals and publications; avoid bias in selection of long-term plot locations; insure adequate spatial replication; insure adequate temporal replication; synthesize retrospective, experimental, and related studies; blend theoretical and empirical models with the means to validate both; obtain periodic research program evaluation; integrate and synthesize with larger and smaller scale research, inventory, and monitoring programs; and develop an extensive outreach program. Using these 14 attributes as a guide, we describe one approach to assess the potential effect of global change on the vegetation of the Front Range of the Colorado Rockies. This self-evaluation helps identify strengthes and weaknesses in our program, and may serve the same role for other landscape ecologists in other programs.

Evaluating progress toward closed forest models based on fluxes of carbon, water and nutrients.

Closed system models are defined as mathematical models of systems having specified boundaries within which all flows into and out of the system are accounted for. Closure is obtained experimentally when we can measure all the flows and do not depend on residuals. The meeting on which this volume is based discussed a range of models and approaches to modeling, and the possibility of achieving closure. There was general agreement that we can develop closed system models of the water balance, carbon cycle and nutrient fluxes at the stand level. Confidence in our ability to account for all the flows is greatest for water, decreasing progressively for carbon and nutrients. The priority areas for research on the carbon balance are belowground processes, foliage dynamics and respiration. The problems requiring particular attention in relation to the water balance are the measurement of interception losses, lateral flow in the soil and evaporation from snow. Areas warranting particular research attention in relation to nutrient fluxes through forest stands are the rates, and the controls on rates, of nutrient uptake by trees, and rates of mineralization with emphasis on the importance of microbial processes at the ecosystem level. Most models are written for uniform conditions. Forests are not uniform so the problem of heterogeneity, and how to deal with it in models, requires considerable attention, as does the question of how to scale up, to deal with large areas. There are a great many forest models of all types and the continual development of new ones may not be an effective use of research resources. There is a need for some assessment of the range of models currently existing, or under development, and for moves toward a directed strategy of model structure and development.

Preformulation method for parenteral preservative efficacy evaluation.

A method is described for rapidly and reliably evaluating parenteral preservative efficacy. Solutions containing antimicrobial preservatives were challenged with microorganisms, sampled from 0.5 to 6 h following introduction of the challenge, cultured, and counted for surviving microbial cells. Data were analyzed by computer according to two models: linear and quadratic. Decimal reduction times (D values) were calculated for each microbial challenge in each preservative solution. A D value of less than or equal to 2 h for bacteria predicts that the preservative system will pass the British Pharmacopoeia (BP) preservative efficacy test, a more rigorous test than the USP test. Fourteen preservative systems were tested in both neutral isotonic saline solutions and neutral regular insulin solutions. D values and correlation coefficients for both models were calculated. The ranking of preservative effectiveness in neutral saline solutions closely correlated with the results found using neutral regular insulin solutions. The most effective preservative systems were found to be 0.3% m-cresol and various combinations of m-cresol and phenol. The advantages and limitations of this method are discussed.

Liquid-chromatographic determination of penbutolol and its principal metabolites in plasma and urine.

We describe a sensitive, specific liquid-chromatographic determination of penbutolol and its 4-hydroxy metabolite in plasma and urine. The method involves a simple organic extraction, evaporation of the solvent, reconstitution in methanol/water, and injection into the chromatograph. Penbutolol, its metabolites, and the internal standard, propranolol, are resolved on a CN reversed-phase column and detected fluorometrically. Conjugates of penbutolol and its 4-hydroxy metabolite may be determined after a 2-h enzymic hydrolysis. Detection limits are in the range of 3 to 12 micrograms/L of plasma. The assay is reproducible and nearly free of interferences. Representative concentrations in blood and urine of normal volunteers are reported.