Evaluation of the BOD POD for estimating percent body fat in collegiate track and field female athletes: a comparison of four methods

This investigation examined the accuracy of the BOD POD on a group of Division I collegiate track and field female athletes (N = 30). Hydrostatic weighing (HW) was used as the gold standard method. Body density (Db) values obtained from the BOD POD (Db BP) were compared with those determined by HW (Db HW). Both Db values were converted to percent body fat (%BF) using the Siri equation for comparison. Percent body fat values obtained from the BOD POD (BF BP) were also compared with those obtained from dual-energy X-ray absorptiometry (DXA, BF DXA) and skinfold (SF, BF SF). The validity of the BOD POD was assessed using repeated-measures analysis of variance (ANOVA), and the relationship between the methods was examined through Pearson correlation. Average Db BP was 0.00890 g x cm(-3) lower (p < 0.05) than Db HW, resulting in a significant overestimation of %BF (p < 0.05) by the BOD POD. Values for BFDXA and BFBP also differed significantly (p < 0.05). On the other hand, BFSF and BF BP were not significantly different. The correlation between percent body fat values obtained from HW (BFHW) and BF BP was good (r = 0.88, SEE = 2.30) as well as between BF SF and BF BP (r = 0.85, SEE = 2.05). Conversely, the correlation between BFDXA and BF BP was poor (r = 0.25, SEE = 5.73). The strong correlation between BF BP and BF HW presented here suggests that the BOD POD has the potential to be used as a body composition analysis tool for female athletes. The advantages of the BOD POD over HW encourage further investigation of this instrument. However, the fact that the BOD POD and SF results did not differ significantly might suggest that the SF could be used in its place until a better rate of accuracy for this instrument is established.     

Percentage of total body fat as estimated by three automatic bioelectrical impedance analyzers

The present study aimed to compare the accuracy of estimating the percentage of total body fat (%TBF) among three bioelectrical impedance analysis (BIA) devices: a single-frequency BIA with four tactile electrodes (SF-BIA4), a single-frequency BIA with eight tactile electrodes (SF-BIA8) and a multi-frequency BIA with eight tactile electrodes (MF-BIA8). Dual-energy x-ray absorptiometry (DXA) and hydrostatic weighing (HW) were used as references for the measured values. Forty-five healthy college student volunteers (21 males: 172.9 +/- 5.5 cm and 65.8 +/- 9.1 kg and 24 females: 160.7 +/- 6.6 cm, 52.6 +/- 6.2 kg) were the subjects. Correlation coefficients between the BIA measurements and the references were calculated. The standard error of estimation (SEE) was calculated by regression analysis when estimating the reference measures (DXA and HW) from the predictor (SF-BIA4, SF-BIA8 and MF-BIA8). The differences in %TBF between the reference and the predictor, calculated by the reference minus the predictor, were plotted against the %TBF measured by the references. The MF-BIA 8 here showed the highest correspondence to the reference and the least estimation error compared with the other BIA methods. It is considered that there is a limit to directly estimate FFM from a regression equation using impedance, weight, height and age as independent variables, and that %TBF can be more accurately estimated by measuring segmental impedances using eight electrodes and multi-frequency electric currents and then estimating total body water from these impedances.     

Factor VIII A3 domain residues 1954-1961 represent an A1 domain-interactive site

Factor VIIIa consists of subunits designated A1, A2, and A3C1C2. Reassociation of the A1 and A3C1C2 subunits monitored by the factor Xa generation assay and fluorescence resonance energy transfer yielded intersubunit affinity values (K(d)) of 58.0 +/- 12.5 and 58.8 +/- 16.8 nM, respectively. These affinity values were equivalent to that previously determined for factor VIII heavy and light chains [Wakabayashi, H., et al. (2001) Biochemistry 40, 10293-10300], suggesting that the A2 domain makes a minimal contribution to the interchain affinity in factor VIII. Ca(2+) showed no effect on A1/A3C1C2 intersubunit affinity (K(d) = 51.6 +/- 16.6 nM), while Cu(2+) enhanced the A1/A3C1C2 intersubunit affinity approximately 5-fold (K(d) = 12.5 +/- 2.3 nM). A synthetic peptide to A3 domain residues 1954-1961 inhibited association of the A1 and A3C1C2 subunits (K(i) = 65.8 +/- 11.9 microM). Three factor VIII point mutants, His1957Ala, Gly1960Val, and His1961Asp, were stably expressed in BHK cells and purified. All mutants exhibited reduced specific activity (39, 42, and 4%, respectively) compared with that of wild-type factor VIII, and their activity was less stable following heat denaturation analysis (t(1/2) values of 13.3 +/- 0.7, 8.7 +/- 0.3, and 8.1 +/- 0.1 min, respectively) compared with that of the wild type (18.8 +/- 0.8 min). This reduced stability appeared to result from an approximately 2-fold increased dissociation rate for the Gly1960Val and His1961Asp dimers as judged by solid-phase binding assays. We propose that residues 1954-1961 of the A3 domain contribute to interactions with the A1 domain, facilitating their association in factor VIII.     

Domain structure of cellobiohydrolase II as studied by small angle X-ray scattering: close resemblance to cellobiohydrolase I

Evidence for a domain structure of cellobiohydrolase II (CBH II, 58 kDa) from Trichoderma reesei (Teeri et al., 1987; Tomme et al., 1988) is corroborated by results from SAXS experiments. They indicate a 'tadpole' structure for the intact CBH II in solution (Dmax = 21.5 +/- 0.5 nm; Rg = 5.4 +/- 0.1 nm) and a more isotropic, ellipsoid shape for the core protein (Dmax = 6.0 +/- 0.3 nm; Rg = 2.1 +/- 0.1 nm). The latter was obtained by partial proteolysis with papain which cleaves the native CBH II to give two fragments (Tomme et al., 1988): the core (45 kDa) with the active (hydrolytic) domain and a smaller fragment (11 kDa) coinciding with the tail part of the model and containing the binding domain for unsoluble cellulose. This peptide fragment is conserved in most cellulolytic enzymes from Trichoderma reesei (Teeri et al., 1987). It contains a conserved region (block A) and glycosylated parts (blocks B and B' duplicated and located N-terminally in CBH II). In spite of different domain arrangements in CBH I (blocks B-A at C-terminals) SAXS measurements (Abuja et al., 1988) indicate similar tertiary structures for both cellobiohydrolases although discrete differences in the tail parts exist.     

Real-time case fatality analysis points to emerging evidence of increasing severity of pandemic (H1N1) 2009

Comment on: Fraser C, Donnelly CA, Cauchemez S, Hanage WP, Van Kerkhove MD, Hollingsworth TD, et al. WHO Rapid Pandemic Assessment Collaboration. Pandemic potential of a strain of influenza A (H1N1): early findings. Science 2009; 324:1557-61.     

Evaluation of the BOD POD for estimating percent fat in female college athletes

The purpose of this investigation was to examine the accuracy of percent body fat (%BF) estimates obtained by air displacement plethysmography (ADP) using the BOD POD Body Composition System compared with hydrostatic weighing (HW) in a group of female college athletes (n = 80). In addition, %BF estimates by skinfold measures (SF) were also obtained for comparison. A lean subset (n = 39) of the sample was also examined. Mean %BF estimated for the entire sample by ADP (21.2 +/- 5.9%) was significantly greater than that determined by HW (19.4 +/- 6.4%) and SF (18.8 +/- 5.5%). Results from the lean subset also revealed that %BF determined by ADP (17.1 +/- 3.7%) was significantly higher than %BF estimates by HW (14.3 +/- 2.8%) and SF (15.2 +/- 3.2%). The regression equation for the entire sample (%BF HW = 0.937%BF ADP - 0.452, r(2) = 0.73, standard error of estimates (SEE) = 3.34) did not differ from the line of identity. In contrast, the line of identity differed significantly from the regression equation for the lean subset of female athletes (%BF HW = 0.48%BF ADP + 6.115, r(2) = 0.41, SEE = 2.18). The results of this investigation indicate that ADP significantly overestimated %BF by 8% in female athletes and by 16% for a leaner subset of the sample compared with HW. It appears that %BF estimates by SF may be more accurate than those obtained by ADP for female college athletes, regardless of body composition. Coaches and trainers evaluating body composition should consider the use of SF before ADP when measuring %BF in female college athletes. Sports scientists should continue to examine the possible gender and body composition bias for ADP.     

Alternative algebraic rate‐integration approach for progress‐curve analysis of enzyme kinetics

A recent article of Zavrel et al. in this journal (Eng. Life Sci. 2010, 10, 191–200) described a comparison of several computer programs for progress‐curve analysis with respect to different computational approaches for parameter estimation. The authors applied both algebraic and dynamic parameter estimations, although they omitted time‐course analysis through the integrated rate equation. Recently, it was demonstrated that progress‐curve analysis through the integrated rate equation can be considered a simple and useful alternative for enzymes that obey the generalized Michaelis–Menten reaction mechanism. To complete this gap, the time‐dependent solution of the generalized Michaelis–Menten equation is here fitted to the progress curves from the Zavrel et al. reference article. This alternative rate‐integration approach for determining the kinetics parameters of Michaelis–Menten‐type enzymes yields the values with the greatest accuracy, as compared with the results obtained by other (algebraic or dynamic) parameter estimations.     

Thermal effects of whole head submersion in cold water on nonshivering humans.

This study isolated the effect of whole head submersion in cold water, on surface heat loss and body core cooling, when the confounding effect of shivering heat production was pharmacologically eliminated. Eight healthy male subjects were studied in 17 degrees C water under four conditions: the body was either insulated or uninsulated, with the head either above the water or completely submersed in each body-insulation subcondition. Shivering was abolished with buspirone (30 mg) and meperidine (2.5 mg/kg), and subjects breathed compressed air throughout all trials. Over the first 30 min of immersion, exposure of the head increased core cooling both in the body-insulated conditions (head out: 0.47 +/- 0.2 degrees C, head in: 0.77 +/- 0.2 degrees C; P < 0.05) and the body-exposed conditions (head out: 0.84 +/- 0.2 degrees C and head in: 1.17 +/- 0.5 degrees C; P < 0.02). Submersion of the head (7% of the body surface area) in the body-exposed conditions increased total heat loss by only 10%. In both body-exposed and body-insulated conditions, head submersion increased core cooling rate much more (average of 42%) than it increased total heat loss. This may be explained by a redistribution of blood flow in response to stimulation of thermosensitive and/or trigeminal receptors in the scalp, neck and face, where a given amount of heat loss would have a greater cooling effect on a smaller perfused body mass. In 17 degrees C water, the head does not contribute relatively more than the rest of the body to surface heat loss; however, a cold-induced reduction of perfused body mass may allow this small increase in heat loss to cause a relatively larger cooling of the body core.     

Discrete wavelet transform: a tool in smoothing kinematic data

Motion analysis systems typically introduce noise to the displacement data recorded. Butterworth digital filters have been used to smooth the displacement data in order to obtain smoothed velocities and accelerations. However, this technique does not yield satisfactory results, especially when dealing with complex kinematic motions that occupy the low- and high-frequency bands. The use of the discrete wavelet transform, as an alternative to digital filters, is presented in this paper. The transform passes the original signal through two complementary low- and high-pass FIR filters and decomposes the signal into an approximation function and a detail function. Further decomposition of the signal results in transforming the signal into a hierarchy set of orthogonal approximation and detail functions. A reverse process is employed to perfectly reconstruct the signal (inverse transform) back from its approximation and detail functions. The discrete wavelet transform was applied to the displacement data recorded by Pezzack et al., 1977. The smoothed displacement data were twice differentiated and compared to Pezzack et al.'s acceleration data in order to choose the most appropriate filter coefficients and decomposition level on the basis of maximizing the percentage of retained energy (PRE) and minimizing the root mean square error (RMSE). Daubechies wavelet of the fourth order (Db4) at the second decomposition level showed better results than both the biorthogonal and Coiflet wavelets (PRE = 97.5%, RMSE = 4.7 rad s-2). The Db4 wavelet was then used to compress complex displacement data obtained from a noisy mathematically generated function. Results clearly indicate superiority of this new smoothing approach over traditional filters.     

Effect of the folk remedy, Bainiku-ekisu, a concentrate of Prunus mume juice, on Helicobacter pylori infection in humans

BACKGROUND: Bainiku-ekisu, a concentrate of Japanese apricot (Prunus mume) juice, is a traditional Japanese folk remedy for treatment of dyspepsia since more than a thousand years ago. Fujita et al. previously reported in vitro antibacterial effect of Bainiku-ekisu to Helicobacter pylori. We conducted an in vivo pilot study to evaluate the possibility that Bainiku-ekisu may have an antibacterial effect on H. pylori in the human stomach. MATERIALS AND METHODS: Consecutive 18 H. pylori-positive subjects were included. Approximately 130 mL 1% Bainiku-ekisu solution was ingested by the subjects twice a day for 12 weeks. Urea breath test (UBT) was performed before ingestion, and 2 and 12 weeks after starting ingestion of Bainiku-ekisu, and UBT values were compared. RESULTS: Bainiku-ekisu therapy resulted in a slight fall in UBT values after 2 weeks (from 30.1 +/- 6 to 23.5 +/- 6 in ITT analysis, p = .094; from 31.2 +/- 6 to 24.7 +/- 6 in PP analysis, p = .124) (data are shown with mean +/- SE). In two instances (11%), the UBT values became negative. Fourteen subjects completed the trial for 12 weeks and there was no significant change in UBT values (from 30.1 +/- 6 to 25.9 +/- 6 in ITT analysis, p = .450; from 35.6 +/- 6 to 31.4 +/- 7 in PP analysis, p = .555). CONCLUSION: Our results are consistent with the antibacterial effect of Bainiku-ekisu on H. pylori in the human stomach. However, the bacteria were not successfully eradicated with 2- or 12-week ingestion of a Bainiku-ekisu solution. Subsequent studies will need to identify a clinically useful regimen.     

Intrinsic uncertainty explains second responses

In the simplest form of signal-detection theory (SDT), all stimuli give rise to equal-variance Gaussian probability density functions (PDFs) of sensation, with means proportional to stimulus intensity. As this simple SDT cannot accurately describe psychometric functions for two-alternative forced-choice (2AFC) detection experiments, it is commonly modified in one of two ways: with a non-linear transducer or intrinsic uncertainty. Most results can adequately be explained by either modification, but Swets et al.'s (1961) two-response 4AFC (2R4AFC) detection experiment is an exception. Simple SDT cannot predict the relationship between first- and second-response accuracies and non-linear transduction does not help. A previously unacknowledged facet of intrinsic uncertainty is that the same uncertainty required to fit 2AFC psychometric functions also produces an excellent fit to Swets et al.'s 2R4AFC results, without requiring any additional assumptions. This result is derived within the context of a primer on SDT.     

Validity of leg-to-leg bioelectrical impedance measurement in highly active women

The aim of this study was to compare the validity of the leg-to-leg bioelectrical impedance analysis (BIA) method with that of anthropometry using hydrostatic weighing (HW) as the criterion test. A secondary objective was to cross-validate previously developed anthropometric regression equations as well as to develop a new regression equation formula based on the anthropometric data collected in this study. Three methods for assessing body composition (HW, BIA, and anthropometric) were applied to 60 women university athletes. The means and standard deviations of age, weight, height, and body mass index (BMI) of athletes were as follows: age, 20.70 +/- 1.43; weight, 56.19 +/- 7.83 kg; height, 163.33 +/- 6.11 cm; BMI, 21.01 +/- 2.63 kg x m(-2). Leg-to-leg BIA (11.82 +/- 2.39) has shown no statistical difference between percentage body fat determined by HW (11.63 +/- 2.42%) in highly active women (p > 0.05). This result suggests that the leg-to-leg BIA and HW methods were somewhat interchangeable in highly active women (R = 0.667; standard error of estimate [SEE] = 1.81). As a result of all cross-validation analyses, anthropometric and BIA plus anthropometric results have generally produced lower regression coefficients and higher SEEs for highly active women between the ages of 18 and 25 years. The regression coefficients (0.903, 0.926) and SEE (1.08, 0.96) for the new regression formulas developed from this study were better than the all the other formulas used in this study.     

New percentage body fat prediction equations for Japanese males

Anthropometry is simple, cheap, portable and non-invasive method for the assessment of body composition. While the Nagamine and Suzuki body density prediction equation has been frequently used to estimate %BF of Japanese, the equation was developed more than 40 years ago and its applicability to the current Japanese population has not been studied. This study aimed to compare %BF results estimated from anthropometry and dual energy X-ray absorptiometry (DXA) in order to examine applicability of the Nagamine and Suzuki equation. Body composition of 45 Japanese males (age: 24.3+/-5.5 years, stature: 171.6+/-5.8 cm, body mass: 62.6+/-7.1 kg, %BF: 15.7+/-5.6%) were assessed using whole-body DXA (Hologic QDR-2000) scan and anthropometry using the protocol of the International Society for the Advancement of Kinanthropometry (ISAK). From anthropometric measurements %BF was calculated using the Nagamine and Suzuki equation. The results showed that the Nagamine and Suzuki equation significantly (p<0.05) underestimated %BF of Japanese males compared to the DXA results. There was a trend towards greater underestimation as the estimated %BF values using DXA increased. New %BF prediction equations were proposed from the DXA and anthropometry results. Application of the proposed equations may assist in more accurate assessment of body fatness in Japanese males living today.     

Validity of the BOD POD for assessing body composition in athletic high school boys

The purpose of this study was to validate the percentage of body fat (%BF) values estimated from the BOD POD (BP) with those obtained from hydrostatic weighing (HW) in athletic American high school boys. Additionally, the %BF values measured via near-infrared interactance (NIR), bioelectrical impedance (BIA), and skinfold (SF) were compared to HW to determine the validity of these measures. Thirty white boys (mean age +/- SD = 15.8 +/- 1.0 years) who where currently participating in organized sports volunteered to have their %BF estimated. Measurements were obtained from NIR, BP, BIA, and SF in random order and concluded with HW. The findings from the present study indicated that the NIR and BIA instruments produced significant (P < 0.008) constant error (CE) and total error (TE) values that were too large to be of practical value (TE > 4.0%BF). The BP produced a significantly (P < 0.008) higher CE with acceptable TE values compared to HW, but compared to all three SF estimations, the BP TE values were higher. Two of the SF equations were nonsignificant (P > 0.008) and had the lowest TE values compared to HW. These data suggest that the BP can produce acceptable body fat measures for athletic white boys but is not superior to estimates made by the SF equations used in this study.     

An evaluation of chemical shift index-based secondary structure determination in proteins: Influence of random coil chemical shifts

Random coil chemical shifts are commonly used to detect protein secondary structural elements in chemical shift index (CSI) calculations. Though this technique is widely used and seems reliable for folded proteins, the choice of reference random coil chemical shift values can significantly alter the outcome of secondary structure estimation. In order to evaluate these effects, we present a comparison of secondary structure content calculated using CSI, based on five different reference random coil chemical shift value sets, to that derived from three-dimensional structures.Our results show that none of the reference random coil data sets chosen for evaluation fully reproduces the actual secondary structures. Among the reference values generally available to date, most tend to be good estimators only of helices. Based on our evaluation, we recommend the experimental values measured by Schwarzinger et al.(2000), and statistical values obtained by Lukin et al. (1997), as good estimators of both helical and sheet content.     

The effect of spironolactone on genital skin 5 alpha-reductase activity

The effect of spironolactone (S) on genital skin 5 alpha-reductase activity (5 alpha-RA) of hirsute women (HW) in vivo as well as in normal genital skin in vitro was evaluated. Thirteen HW (Ferriman-Gallwey score of 23.3 +/- 2.8) received S 100 mg twice a day for a month. Twenty-three non-hirsute women were selected as controls for the assessment of genital skin 5 alpha-RA. S was added to incubations of genital skin from 9 additional controls in vitro in concentrations from 1.2 X 10(-8) to 10(-5) M. HW had significantly higher conversion ratios (CR) of T to DHT compared to controls (P less than 0.05). Post treatment values for the CR T to DHT were significantly lower than prior to S (17.5 +/- 1.7 and 8.05 +/- 1.2%, P less than 0.05) and the mass of DHT produced also decreased by 37 +/- 9% (P less than 0.05). The CR T to 3 alpha-diol decreased by 30 +/- 9% (P less than 0.05). In 11 of 13 women, a significant reduction of 5 alpha-RA was demonstrated while in 2 patients the activity remained unchanged. The maximum in vitro inhibitory effect of S on the CR T to DHT occurred with a concentration of 1.2 X 10(-5) M (P less than 0.01). In conclusion, S has a direct inhibitory effect on 5 alpha-RA. The beneficial effect of S treatment in HW may be related, in part, to this inhibition of 5 alpha-RA.     

Anatomical basis for an apparent paradox concerning conduction velocities of two identified axons in Aplysia.

Larger axons usually have faster conduction velocities, lower thresholds, and larger extracellular action potentials than smaller axons. However, it has been shown that the largest fiber, R2, in the right pleurovisceral connective of the marine mollusc, Aplysia, has a higher threshold and a slower conduction velocity than does the smaller axon of cell RI, even though the amplitude of R2's spike is larger than R1's spike. One explanation of this apparent parodox is that the two axons have different "intrinsic membrane and axoplasmic constants" (Goldman, L. (1961), J. Cell Comp. Physiol. 57: 185-191). However, the deep infolding of R2's axonal membrane suggested that differences in the shape of the two axons might also account for the paradox. Accordingly, we measured the conduction velocities of the two axons and then examined the same axons in the electron microscope in order to measure their volumes and surface areas. Our morphological observations indicate that the extensive infolding of surface membrane causes R2 to have a smaller volume to surface area ratio than R1. Thus, since conduction velocity is proportional to the square root of the volume to surface area ratio (Hodgkin, A.L. (1954), J. Physiol. 125: 221-224), it is predictable that the smaller axon would have a faster conduction velocity. The results suggest that the paradoxical conduction velocities can be explained largely as resulting from differences in the shapes of the two axons. However, certain discrepancies between the measured and the predicted values suggest that other factors are contributing as well.     

Effects of acidified sodium chlorite, cetylpyridinium chloride and hot water on populations of Listeria monocytogenes and Staphylococcus aureus on beef

AIMS: The present study was designed to determine the individual and combined effects of acidified sodium chlorite (ASC, 0.1%, 24 +/- 1 degrees C), cetylpyridinium chloride (CPC, 0.5%, 24 +/- 1 degrees C) and hot water (HW, 93 +/- 1 degrees C) treatments on the survival of Listeria monocytogenes and Staphylococcus aureus. METHODS AND RESULTS: Beef samples inoculated with L. monocytogenes and S. aureus were treated with nine different applications singly or in combination. Treatment groups comprised (i) untreated control; (ii) sterile tap water; (iii) 0.1% ASC; (iv) 0.5% CPC; (v) HW; (vi) HW followed by 0.1% ASC; (vii) HW followed by 0.5% CPC; (viii) 0.1% ASC followed by HW; (ix) 0.5% CPC followed by HW. Compared with the untreated control group, the reductions in L. monocytogenes populations were 1.14-2.31 log CFU g(-1), while the reductions in S. aureus populations were 0.83-2.74 log CFU g(-1) on day 0. CONCLUSION: The reduction effect that occurred after combined treatment with ASC followed by HW, HW followed by ASC, CPC followed by HW and HW followed by CPC was found to be significantly greater (P < 0.05) than after treatment with ASC and CPC alone on days 0, 2 and 4 of storage. SIGNIFICANCE AND IMPACT OF THE STUDY: ASC, CPC and HW treatments can be used to reduce L. monocytogenes and S. aureus, which would provide an additional measure of safety on the production line.     

Solubility of Freon 22 in human blood and lung tissue

The solubility of Freon 22 in human blood and lung tissue was determined using the chromatographic method of Wagner et al. (J. Appl. Physiol. 36: 600-605, 1974). In normal human blood, the mean Bunsen coefficient of solubility (alpha B) was 0.804 cm3 STPD.cm-3.ATA-1 at 37 degrees C. It increased with hematocrit (Hct) according to the equation alpha B = 0.274 Hct + 0.691. Tissue homogenates were prepared from macroscopically normal lung pieces obtained at thoracotomy from eight patients undergoing resection for lung carcinoma. The Bunsen solubility coefficients were 0.537 +/- 0.068 and 0.635 +/- 0.091 in washed and unwashed lung, respectively. These values can be used in the determination of both cardiac output and pulmonary tissue volume in humans by use of the rebreathing technique.