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To provide new estimates of the average Ca requirement for men and women, we determined the dietary Ca intake required to maintain neutral Ca balance. Ca balance data (Ca intake - [fecal Ca + urinary Ca]) were collected from 154 subjects (females: n=73, weight=-77.1±18.5 kg, age=47.0±18.5 y [range: 20-75 y]; males: n=81, weight=-76.6±12.6 kg, age=28.2±7.7 y [range: 19-64 y]) who participated in 19 different tightly-controlled feeding studies conducted in a metabolic unit. Balance data from the last 6-14 d of each dietary period (rain. length 28 d) of each study (1-9 observations per subject) were analyzed. Data were excluded if individual intakes of Mg, Cu, Fe, P, or Zn fell below the Estimated Average Requirements or exceeded the 99th %tile of 1994 CSFII usual intakes (for Fe, above the UL). Daily intakes of Ca ranged between 415 and 1740 mg. The relation between intake and output was examined by fitting random coefficient models using SAS Proc Mixed. Coefficients were included to test for gender differences. The models predicted neutral Ca balance (defined as Ca output (Y) equal to Ca intake (C)) of 741 mg/d [507 - 1035, 95% prediction interval (PI); Y = 148.29 + 0.80C], 9.4 mg/kg/d [6.4 - 12.9, 95% PI; Y = 1.44 + 0.85C], or 0.28 mg/kcal/d [0.19 - 0.38, 95% PI; Y = 0.051 + 0.816]. Neither age nor sex affected the estimates when expressed as mg/d or mg/kg/d. The findings suggest a lower Ca requirement for men and women than estimated previously. [ABSTRACT FROM AUTHOR]

The ability of WBC to undergo apoptosis is an essential feature in the maintenance and regulation of the immune response. We have developed a method for the assessment of WBC potential for apoptosis (high expression of 3′-hydroxyl ends in DNA) in a whole blood in vitro system. Whole blood collected from free-living individuals (n = 30) was held (15 - 60 min; room temp; heparinized glass vacutainers) then aliquoted for incubation (180 min at 37° C) with the apoptosis inducers, HP (25.4 mmol) or CHX (9.5 mmol), or with no inducer for 0 min or 180 min. Following lysing of RBC, washed WBC were fixed (1% paraformaldehyde; 60 min) and permeabilized (70% ETOH; 18 h). Flow cytometry differentiated WBC by size and complexity, apoptotic subpopulation (fluorescein labeled antiBrdU monoclonal antibody) and cellular DNA content (propidium iodide). Bivariate analysis and logical gating techniques based on the distribution of a consistently identifiable cell population allowed for the standardized identification of apoptotic cells. An apoptotic control standard (human lymphoma cell line) confirmed the labeling reagents performance. Mean percent change in apoptosis was significantly greater in HP (3.95 %), and CHX (5.36 %), treatments, than at 0 min (1.04 %, p < 0.0003), but not at 180 min (1.95 %, p = 0.21). This method appears capable of measuring the apoptotic potential of WBC maintained in a near physiologic environment. [ABSTRACT FROM AUTHOR]

To expand on reports from this laboratory that low dietary boron may affect energy substrate utilization, we determined whether low dietary boron during early development promotes manifestation of the metabolic syndrome in adult offspring. Sprague-Dawley dams were fed either a boron-low (BL; ∼0.1 mg B/kg) or boron-supplemented (BS; ∼3.0 mg B/kg) diet from 75 d prior to breeding (with diet-matched males) to weaning of pups. Female weanlings (21 d of age) were re-randomized and fed either the BL or BS diet for 63 d. Beginning at 28 d post weaning, maternal boron deprivation, but not post-weaning boron nutriture, increased body weight (p = 0.0001) in offspring (215 vs 192 g at 84 d of age). Also, at 84 d of age, maternal boron deprivation increased serum concentrations of triglycerides (0.54 vs 0.47 mmol/L, p = 0.005) and total cholesterol (2.04 vs 1.89 mmol/L, p = 0.004) and decreased alkaline phosphatase (136 vs 124 U/L; p = 0.004). Independent of maternal nutriture, post-weaning boron deprivation increased serum concentrations of glucose (10.77 vs 10.49 mmol/L; p = 0.001). The findings that a maternal diet limited in boron content (i.e., one low in fruit, nut, vegetable, and legume content) may increase manifestation of some components of the metabolic syndrome in adult offspring, including a 10% increase in body weight, suggests a possible role for boron in prevention of the syndrome. [ABSTRACT FROM AUTHOR]