Color Alignment for Relative Color Constancy via Non-Standard References

Relative colour constancy is an essential requirement for many scientific imaging applications. However, most digital cameras differ in their image formations and native sensor output is usually inaccessible, e.g., in smartphone camera applications. This makes it hard to achieve consistent colour assessment across a range of devices, and that undermines the performance of computer vision algorithms. To resolve this issue, we propose a colour alignment model that considers the camera image formation as a black-box and formulates colour alignment as a three-step process: camera response calibration, response linearisation, and colour matching. The proposed model works with non-standard colour references, i.e., colour patches without knowing the true colour values, by utilising a novel balance-of-linear-distances feature. It is equivalent to determining the camera parameters through an unsupervised process. It also works with a minimum number of corresponding colour patches across the images to be colour aligned to deliver the applicable processing. Three challenging image datasets collected by multiple cameras under various illumination and exposure conditions, including one that imitates uncommon scenes such as scientific imaging, were used to evaluate the model. Performance benchmarks demonstrated that our model achieved superior performance compared to other popular and state-of-the-art methods.

When You Put It that Way: Framing Gender Equality Initiatives to Improve Engagement among STEM Academics

A number of high-profile gender equality initiatives (GEIs) are intended to address women's underrepresentation in science. However, attitudes toward such initiatives can be negative. In two experiments with STEM academics, we examined how GEIs can be best framed to improve attitudes toward them. In study 1 (N = 113), we manipulated the framing of GEI leadership (led by a man or woman) and GEI focus (benefitting men and women or benefitting women only). The men were more supportive of GEIs benefitting both men and women because of fewer concerns of unfair treatment and more internal motivations to engage with GEIs. The women's level of support was unaffected by framing. In study 2 (N = 151), we framed GEIs as either supported by university management or not and either internally or externally driven. Support was greater for internally driven GEIs. The impact of management support depended on the academics’ experience with GEIs. This research makes evidence-based recommendations for the implementation of GEIs to improve their effectiveness.

Global FKRP Registry: observations in more than 300 patients with Limb Girdle Muscular Dystrophy R9

Objective

The Global FKRP Registry is a database for individuals with conditions caused by mutations in the Fukutin‐Related Protein (FKRP) gene: limb girdle muscular dystrophy R9 (LGMDR9, formerly LGMD2I) and congenital muscular dystrophies MDC1C, Muscle–Eye–Brain Disease and Walker–Warburg Syndrome. The registry seeks to further understand the natural history and prevalence of FKRP‐related conditions; aid the rapid identification of eligible patients for clinical studies; and provide a source of information to clinical and academic communities.

Methods

Registration is patient‐initiated through a secure online portal. Data, reported by both patients and their clinicians, include: age of onset, presenting symptoms, family history, motor function and muscle strength, respiratory and cardiac function, medication, quality of life and pain.

Results

Of 663 registered participants, 305 were genetically confirmed LGMDR9 patients from 23 countries. A majority of LGMDR9 patients carried the common mutation c.826C > A on one or both alleles; 67.9% were homozygous and 28.5% were compound heterozygous for this mutation. The mean ages of symptom onset and disease diagnosis were higher in individuals homozygous for c.826C > A compared with individuals heterozygous for c.826C > A. This divergence was replicated in ages of loss of running ability, wheelchair‐dependence and ventilation assistance; consistent with the milder phenotype associated with individuals homozygous for c.826C > A. In LGMDR9 patients, 75.1% were currently ambulant and 24.6%, nonambulant (unreported in 0.3%). Cardiac impairment was reported in 23.2% (30/129).

Interpretation

The Global FKRP Registry enables the collection of patient natural history data, which informs academics, healthcare professionals and industry. It represents a trial‐ready cohort of individuals and is centrally placed to facilitate recruitment to clinical studies.

The Efficiency of Color Space Channels to Quantify Color and Color Intensity Change in Liquids, pH Strips, and Lateral Flow Assays with Smartphones

Bottom-up, end-user based feed, and food analysis through smartphone quantification of lateral flow assays (LFA) has the potential to cause a paradigm shift in testing capabilities. However, most developed devices do not test the presence of and implications of inter-phone variation. Much discussion remains regarding optimum color space for smartphone colorimetric analyses and, an in-depth comparison of color space performance is missing. Moreover, a light-shielding box is often used to avoid variations caused by background illumination while the use of such a bulky add-on may be avoidable through image background correction. Here, quantification performance of individual channels of RGB, HSV, and LAB color space and ΔRGB was determined for color and color intensity variation using pH strips, filter paper with dropped nanoparticles, and colored solutions. LAB and HSV color space channels never outperformed the best RGB channels in any test. Background correction avoided measurement variation if no direct sunlight was used and functioned more efficiently outside a light-shielding box (prediction errors < 5%/35% for color/color intensity change). The system was validated using various phones for quantification of major allergens (i.e., gluten in buffer, bovine milk in goat milk and goat cheese), and, pH in soil extracts with commercial pH strips and LFA. Inter-phone variation was significant for LFA quantification but low using pH strips (prediction errors < 10% for all six phones compared). Thus, assays based on color change hold the strongest promise for end-user adapted smartphone diagnostics.

The end user sensor tree: An end-user friendly sensor database

Detailed knowledge regarding sensor based technologies for the detection of food contamination often remains concealed within scientific journals or divided between numerous commercial kits which prevents optimal connectivity between companies and end-users. To overcome this barrier The End user Sensor Tree (TEST) has been developed. TEST is a comprehensive, interactive platform including over 900 sensor based methods, retrieved from the scientific literature and commercial market, for aquatic-toxins, mycotoxins, pesticides and microorganism detection. Key analytical parameters are recorded in excel files while a novel classification system is used which provides, tailor-made, experts' feedback using an online decision tree and database introduced here. Additionally, a critical comparison of reviewed sensors is presented alongside a global perspective on research pioneers and commercially available products. The lack of commercial uptake of the academically popular electrochemical and nanomaterial based sensors, as well as multiplexing platforms became very apparent and reasons for this anomaly are discussed.

FPGA-Based Processor Acceleration for Image Processing Applications

FPGA-based embedded image processing systems offer considerable computing resources but present programming challenges when compared to software systems. The paper describes an approach based on an FPGA-based soft processor called Image Processing Processor (IPPro) which can operate up to 337 MHz on a high-end Xilinx FPGA family and gives details of the dataflow-based programming environment. The approach is demonstrated for a k-means clustering operation and a traffic sign recognition application, both of which have been prototyped on an Avnet Zedboard that has Xilinx Zynq-7000 system-on-chip (SoC). A number of parallel dataflow mapping options were explored giving a speed-up of 8 times for the k-means clustering using 16 IPPro cores, and a speed-up of 9.6 times for the morphology filter operation of the traffic sign recognition using 16 IPPro cores compared to their equivalent ARM-based software implementations. We show that for k-means clustering, the 16 IPPro cores implementation is 57, 28 and 1.7 times more power efficient (fps/W) than ARM Cortex-A7 CPU, nVIDIA GeForce GTX980 GPU and ARM Mali-T628 embedded GPU respectively.

FPGA-Based Soft-Core Processors for Image Processing Applications

With security and surveillance, there is an increasing need to process image data efficiently and effectively either at source or in a large data network. Whilst a Field-Programmable Gate Array has been seen as a key technology for enabling this, the design process has been viewed as problematic in terms of the time and effort needed for implementation and verification. The work here proposes a different approach of using optimized FPGA-based soft-core processors which allows the user to exploit the task and data level parallelism to achieve the quality of dedicated FPGA implementations whilst reducing design time. The paper also reports some preliminary progress on the design flow to program the structure. An implementation for a Histogram of Gradients algorithm is also reported which shows that a performance of 328 fps can be achieved with this design approach, whilst avoiding the long design time, verification and debugging steps associated with conventional FPGA implementations.

Cytotoxic hydrogen bridged ruthenium quinaldamide complexes showing induced cancer cell death by apoptosis

This report presents the first known p-cymene ruthenium quinaldamide complexes stabilised by a hydrogen-bridging atom, which are cytotoxic and show induced cancer cell death by apoptosis.

Mapping the differences in care for 5,000 spinal muscular atrophy patients, a survey of 24 national registries in North America, Australasia and Europe

Spinal muscular atrophy (SMA) is an autosomal recessive genetic disorder characterised by the degeneration of motor neurons and progressive muscle weakness. It is caused by homozygous deletions in the survival motor neuron gene on chromosome 5. SMA shows a wide range of clinical severity, with SMA type I patients often dying before 2 years of age, whereas type III patients experience less severe clinical manifestations and can have a normal life span. Here, we describe the design, setup and utilisation of the TREAT-NMD national SMA patient registries characterised by a small, but fully standardised set of registry items and by genetic confirmation in all patients. We analyse a selection of clinical items from the SMA registries in order to provide a snapshot of the clinical data stratified by SMA subtype, and compare these results with published recommendations on standards of care. Our study included 5,068 SMA patients in 25 countries. A total of 615 patients were ventilated, either invasively (178) or non-invasively (437), 439 received tube feeding and 455 had had scoliosis surgery. Some of these interventions were not available to patients in all countries, but differences were also noted among high-income countries with comparable wealth and health care systems. This study provides the basis for further research, such as quality of life in ventilated SMA patients, and will inform clinical trial planning.

The TREAT-NMD Duchenne muscular dystrophy registries: conception, design, and utilization by industry and academia

Duchenne muscular dystrophy (DMD) is an X-linked genetic disease, caused by the absence of the dystrophin protein. Although many novel therapies are under development for DMD, there is currently no cure and affected individuals are often confined to a wheelchair by their teens and die in their twenties/thirties. DMD is a rare disease (prevalence <5/10,000). Even the largest countries do not have enough affected patients to rigorously assess novel therapies, unravel genetic complexities, and determine patient outcomes. TREAT-NMD is a worldwide network for neuromuscular diseases that provides an infrastructure to support the delivery of promising new therapies for patients. The harmonized implementation of national and ultimately global patient registries has been central to the success of TREAT-NMD. For the DMD registries within TREAT-NMD, individual countries have chosen to collect patient information in the form of standardized patient registries to increase the overall patient population on which clinical outcomes and new technologies can be assessed. The registries comprise more than 13,500 patients from 31 different countries. Here, we describe how the TREAT-NMD national patient registries for DMD were established. We look at their continued growth and assess how successful they have been at fostering collaboration between academia, patient organizations, and industry.

Evaluation of novel genetic algorithm generated schemes for positron emission tomography (PET)/magnetic resonance imaging (MRI) image fusion

The use and benefits of a multimodality approach in the context of breast cancer imaging are discussed. Fusion techniques that allow multiple images to be viewed simultaneously are discussed. Many of these fusion techniques rely on the use of color tables. A genetic algorithm that generates color tables that have desired properties such as satisfying the order principle, the rows, and columns principle, have perceivable uniformity and have maximum contrast is introduced. The generated 2D color tables can be used for displaying fused datasets. The advantage the proposed method has over other techniques is the ability to consider a much larger set of possible color tables, ensuring that the best one is found. We asked radiologists to perform a set of tasks reading fused PET/MRI breast images obtained using eight different fusion techniques. This preliminary study clearly demonstrates the need and benefit of a joint display by estimating the inaccuracies incurred when using a side-by-side display. The study suggests that the color tables generated by the genetic algorithm are good choices for fusing MR and PET images. It is interesting to note that popular techniques such as the Fire/Gray and techniques based on the HSV color space, which are prevalent in the literature and clinical practice, appear to give poorer performance.

Chronic dietary fiber supplementation with wheat dextrin does not inhibit calcium and magnesium absorption in premenopausal and postmenopausal women

This placebo-controlled, randomized, crossover clinical study examined the effect of chronic wheat dextrin intake on calcium and magnesium absorption. Forty premenopausal and post menopausal women (mean ± SD age 49.9 ± 9.8 years) consumed wheat dextrin or placebo (15 g/day) for 2 weeks prior to (45)calcium ((45)Ca) and (26)magnesium ((26)Mg) absorption testing. After a standardized breakfast, serial blood and urine samples were obtained. The mean ± SD area under the curve from 0 to 9 h for (45)Ca specific activity was 0.81 ± 0.21 for wheat dextrin and 0.82 ± 0.22 for placebo, showing that wheat dextrin had no effect on calcium absorption. The mean ± SD percentage excess of (26)Mg/(24)Mg was 7.8% ± 2.1% for wheat dextrin and 7.9% ± 2.6% for placebo, showing that wheat dextrin had no effect on magnesium absorption. In conclusion, chronic wheat dextrin consumption did not inhibit calcium or magnesium absorption from the gastrointestinal tract in women.

The selection and prevalence of natural and fortified calcium food sources in the diets of adolescent girls

OBJECTIVE

To assess the impact of calcium-fortified food and dairy food on selected nutrient intakes in the diets of adolescent girls.

DESIGN

Randomized controlled trial, secondary analysis.

SETTING AND PARTICIPANTS

Adolescent girls (n = 149) from a midwestern metropolitan area participated in randomized controlled trials of bone physiology from 1997 to 2008.

INTERVENTION

Subjects randomly assigned to a high-calcium (HC) diet supplying 1,500 mg calcium/d, or their usual diet (UC).

MAIN OUTCOME MEASURES

Dietary intake was assessed from 3-day food records and calcium intakes categorized by food source. Food group composites, representing calcium-fortified and dairy food categories, were examined for their relative nutrient contributions. Student t tests were used to evaluate differences in selected nutrient intakes between the 2 study groups.

RESULTS

Dairy food contributed 68% of the total mean 1,494 mg calcium/d in the HC group, and calcium-fortified food contributed 304 mg calcium. In the UC group, dairy food contributed 69% of the total mean 765 mg calcium/d and calcium-fortified food contributed 50 mg calcium. Nutrient profiles of the dairy composites differed significantly from the calcium-fortified composites (P < .05).

CONCLUSIONS AND IMPLICATIONS

Dairy food was the primary source of calcium selected by these adolescent girls; calcium-fortified food augmented calcium intakes.

Dietary consistency and the midline sutures in growing pigs

OBJECTIVES

The purpose of this study was to investigate the effects of reduced masticatory function on midline suture growth and morphology in growing pigs.

SETTING AND SAMPLE POPULATION

The sample was 20 pigs separated into two dietary groups and raised at the Department of Anthropology, Harvard University. Midline suture specimens were analyzed at the Department of Orthodontics, University of Washington.

MATERIALS AND METHODS

Ten farm pigs and 10 minipigs, all male, were randomly assigned to hard (n = 9) and soft-diet (n = 11) groups. Fluorochromic mineral labels were administered to document bone apposition, and the animals were killed after 12 weeks. Undecalcified sections of the interfrontal, interparietal, internasal, and intermaxillary sutures were evaluated for bone quantity and sutural thickness, interdigitation ratio and growth rate.

RESULTS

Soft-diet pigs were characterized by a slower rate of weight gain and less bone than their hard-diet counterparts. Even after correction for weight gain, soft-diet pigs had reduced suture growth rate and thickness. However, no difference in interdigitation ratio was detected between dietary groups.

CONCLUSIONS

Restriction to a soft diet reduces midline suture growth and bone apposition in the growing pig.

The effects of tooth extraction on alveolar bone biomechanics in the miniature pig, Sus scrofa

OBJECTIVE

This study investigated the role of occlusion in the development of biomechanical properties of alveolar bone in the miniature pig, Sus scrofa. The hypothesis tested was that the tissues supporting an occluding tooth would show greater stiffness and less strain than that of a non-occluding tooth.

DESIGN

Maxillary teeth opposing the erupting lower first molar (M(1)) were extracted on one side. Occlusion developed on the contralateral side. Serially administered fluorochrome labels tracked bone mineralisation apposition rate (MAR). A terminal experiment measured in vivo buccal alveolar bone strain on occluding and non-occluding sides during mastication. Ex vivo alveolar strains during occlusal loading were subsequently measured using a materials testing machine (MTS/Sintech). Whole specimen stiffness and principal strains were calculated.

RESULTS

MAR tended to be higher on the extraction side during occlusion. In vivo buccal shear strains were higher in the alveolar bone of the occluding side vs. the extraction side (mean of 471 microvarepsilon vs. 281 microvarepsilon, respectively; p=0.04); however, ex vivo shear strains showed no significant differences between sides. Stiffness differed between extraction and occlusion side specimens, significantly so in the low load range (344 vs. 668 MPa, respectively; p=0.04).

CONCLUSIONS

Greater in vivo shear strains may indicate more forceful chews on the occluding side, whereas the similarity in ex vivo bone strain magnitude suggests a similarity in alveolar bone structure and occlusal load transmission regardless of occlusal status. The big overall change in specimen stiffness that was observed was likely attributable to differences in the periodontal ligament rather than alveolar bone.

Preponderance of the evidence: an example from the issue of calcium intake and body composition

Meta-analysis is typically applied to studies developed in fairly mature fields, but may be ill-suited for younger fields in which most of the evidence comes from studies that were designed for other endpoints entirely and that are often significantly underpowered for the effect in question. Here, there are no generally accepted methods for getting a grasp on the preponderance of the evidence. In this review, one way of doing so is proposed and the recently emergent literature concerning calcium intake and body composition is used as an illustration of how such an approach might be used.

Calcium fortificants: overview and strategies for improving calcium nutriture of the U.S. population

Despite more than 20 y of awareness of the importance of calcium to health, U.S. calcium intakes remain suboptimal. Fortification of foods with shortfall nutrients is probably the optimal strategy for dealing with widespread nutrient deficiencies, as it has the best chance of reaching the population segments most at risk, as contrasted with attempts at changing individuals' food choices or relying on voluntary supplement taking. Given the wide array of potential calcium fortificants and fortification levels, there is not much to guide manufacturers interested in improving the nutritional value of their products. In this review, we assemble the calcium salts/complexes that have been used or proposed for use as fortificants and describe certain of their measured characteristics that relate to incorporation into foods, particularly what is known of their absorbability. The calcium salts most commonly used as supplements or fortificants exhibit similar absorbability when tested in pure chemical form. Choice of salt will depend mainly upon cost, compatability with the manufacturing process, and consumer acceptability. However, interaction with food, tablet, or beverage matrices can degrade intrinsic absorbability substantially. As a consequence, each product must be explicitly tested to establish the degree to which its calcium is available to consumers.

Nutrient effects on the calcium economy: emphasizing the potassium controversy

The calcium economy is a dynamic state influenced by fluxes in dietary calcium intake, intestinal calcium absorption, and renal calcium conservation. The relationship of selected bone-related nutrients to these calcium fluxes exhibits both constructive and destructive interactions that affect the overall state of calcium balance. The basis of the calcium requirement and the impact of vitamin D, protein, phosphorus, sodium, and caffeine on the calcium economy are reviewed. Against this background, emerging data on potassium are presented. Data from balance studies of healthy white women at midlife were reviewed to assess the effect of diet potassium on the calcium economy under steady-state conditions. Potassium was inversely associated with both urinary calcium excretion and intestinal calcium absorption, yielding no significant net change in calcium balance. In the population reported on here, dairy, meat, and cereal grains together contributed 56%, and fruits and vegetables 44%, of total dietary potassium. To the extent that fruit and vegetable potassium is a surrogate for high bicarbonate, this cohort did not have a dietary intake pattern allowing for measurement or interpretation of the potential effect of a high-bicarbonate-containing diet on long-term steady-state calcium balance. Potassium itself is uniformly well absorbed regardless of the dietary source. Mean 24-h urinary potassium averaged 92% of dietary intake. According to nationwide food consumption surveys, milk is the number 1 single food source of potassium in all age groups in the United States.

The efficacy of amino acid-based formulas in relieving the symptoms of cow's milk allergy: a systematic review

The aim of this systematic review was to evaluate the efficacy of amino acid-based formulas (AAF) in patients with cow's milk allergy (CMA). Studies were identified using electronic databases and bibliography searches. Subjects eligible for inclusion were patients of any age with CMA or symptoms suggestive of it. Comparisons of interest were AAF vs. extensively hydrolysed formula (eHF), AAF vs. soy-based formula (SF) and AAF vs. cow's milk or cow's milk-based formula. Outcomes of interest were gastrointestinal (GI), dermatological, respiratory and behavioural symptoms as well as growth. A total of 20 studies [three head-to-head randomized controlled trials (RCTs), three cross-over challenge RCTs, seven clinical trials (CTs) and seven case reports (CRs)] were included in the review. In infants with confirmed or suspected CMA, the use of an AAF was shown to be safe and efficacious. Findings from RCT comparisons of AAF with eHF showed that both formulas are equally efficacious at relieving the symptoms of CMA in confirmed or suspected cases. However, infants in specific subgroups (e.g. non-IgE mediated food-induced gastro-enterocolitis-proctitis syndromes with failure to thrive, severe atopic eczema, or with symptoms during exclusive breastfeeding) were more likely overall to benefit from AAF, as intolerance to eHF may occur. In such cases, symptoms persisting despite eHF feeding usually remit on AAF, and catch-up growth may be seen. Meta-analysis of the findings was not possible due to lack of homogenous reporting of outcomes in the original trials. This systematic review shows clinical benefit from use of AAF in both symptoms and growth in infants and children with CMA who fail to tolerate eHF. Further studies are required to determine the relative medical or economic value of initial treatment with AAF in infants at high risk of eHF intolerance.

Calcium Fortification Systems Differ in Bioavailability

The objective of this study was to compare the bioavailability of calcium from two fortification systems used in orange juice. The design was randomized crossover, within-subject. The subjects were 25 healthy premenopausal women in an academic health sciences center. Two commercially marketed calcium-fortified orange juices, ingested in an amount providing 500 mg calcium, were taken at breakfast after an overnight fast. The two fortification systems tested were calcium citrate malate and a combination of tricalcium phosphate and calcium lactate (tricalcium phosphate/calcium lactate). The main outcome measure was the area under the curve (AUC) for the increase in serum calcium from 0 to 9 hours after ingesting the test calcium source. Statistical analyses performed were repeated measures analysis of variance, testing source, and sequence. AUC 9 was 48% greater for calcium citrate malate than for tricalcium phosphate/calcium lactate ( P < .001); absorbed calcium calculated from AUC 9 values (mean+/-standard error of the mean) was 148+/-9.0 mg and 100+/-8.9 mg for calcium citrate malate and tricalcium phosphate/calcium lactate, respectively. The results indicate that equivalent calcium contents on a nutritional label do not guarantee equivalent nutritional value. Nutritionists and dietetics professionals should encourage manufacturers of fortified products to provide information on bioavailability.

Potassium Intake and the Calcium Economy

BACKGROUND

Dietary potassium intake (K) lowers urinary calcium (Ca) excretion and, in short-term studies, may improve Ca balance.

PURPOSE

Our objective was to assess K effects on the Ca economy under steady-state conditions.

DESIGN

8-day, inpatient metabolic studies of nitrogen, phosphorus, and Ca balance, combined with dual isotopic Ca tracer kinetics studies. Study diet matched to prestudy nutrient intakes.

SUBJECTS

191 single women studied from 1-5 times at approximately 5-year intervals, for a total of 644 inpatient studies. Median age at time of study: 50.2 yrs; 301 studies were performed postmenopausally without hormone replacement; 343 were either premenopausal or postmenopausal but on estrogen replacement therapy.

RESULTS

Dietary K was highly significantly associated with urinary Ca excretion, with a coefficient of -0.0109 mmol urine Ca/mmol diet K. However, dietary K was negatively correlated with dual-tracer Ca absorption (coefficient for Ca absorption fraction: -0.00094/mmol dietary K), and was not associated with urine Ca after adjustment for Ca absorption.

CONCLUSION

While a high K diet (i.e., one rich in fruits, vegetables, and dairy products) has multiple health benefits and clearly lowers urine Ca, it does not seem to exert any appreciable net influence on the Ca economy, largely because the reduced calciuria is offset by reduction of intestinal absorption. We note, however, that since the high K intakes in our studies come more from milk and meat than from fruits and vegetables, we cannot exclude a possible balance effect for different food sources of K.

Determinants of endogenous calcium entry into the gut

BACKGROUND

In addition to food sources, calcium enters the gut by way of digestive secretions and shed mucosa. In health, such entry is as large as or larger than urinary calcium excretion. Because calcium absorption is inefficient, most of this endogenous intestinal calcium is excreted.

OBJECTIVE

Our aim was to determine the dietary, anthropometric, and physiologic determinants of calcium entering the digestive stream from endogenous sources.

DESIGN

Multiple regression modeling of intake and excretion data was used with 553 metabolic balance and kinetics studies performed in 190 midlife, white women.

RESULTS

Endogenous intestinal calcium averaged 3.29 +/- 0.83 mmol/d. Multiple regression models explaining variation in this endogenous intestinal calcium were developed with use of dietary intake, anthropometric, and serum mineral variables. All 3 groups of predictor variables individually explained up to 22% of the variation in measured values for endogenous intestinal calcium. A composite model, incorporating all 3 groups explained 29% of the variation, with phosphorus and meat protein intakes, height, weight, and serum calcium and phosphorus concentrations all independently entering the model. Phosphorus intake dominated over all the other predictors, explaining 20% of the variance all by itself, with endogenous intestinal calcium rising by 0.037 mmol for every 1 mmol of phosphorus ingested. Meat protein (but not nonmeat protein) was the only other significant dietary contributor, exhibiting a negative coefficient.

CONCLUSION

As a first approximation, the amount of endogenous calcium entering the digestive stream rises with body size and with the amount of phosphorus-rich food consumed.

The effect of soy protein isolate on bone metabolism

OBJECTIVE

This double-blind, 15-month pilot study was designed to investigate the effect of soy protein isolate with varying concentrations of isoflavones on early postmenopausal bone loss and lipids.

DESIGN

A total of 65 women, with a mean age of 55 years and 7.5 years since menopause, were randomized to one of three groups; soy protein with 96 mg isoflavones/day, soy with 52 mg isoflavones/day, or soy without isoflavones (< 4 mg isoflavones/day). Soy was given for 9 months and then discontinued; participants were followed for an additional 6 months. Bone mineral density (BMD) and blood lipids were measured during this time.

RESULTS

Measurement of serum isoflavones at 3 months showed dose-related increases in the three groups. There was no significant effect of the soy supplements on BMD of the spine or femoral neck in any of the three groups. BMD increased significantly in the trochanter at 9 months (P = 0.0219) and at 15 months (P < 0.05) in the group given isoflavone-free soy compared with the other two groups. There was no significant effect of soy on lipid metabolism at the end of the intervention.

CONCLUSION

The present study did not find a significant positive effect of soy protein isolate supplemented with isoflavones on BMD and the serum lipid profile in early postmenopausal women.

Effect of yogurt on a urinary marker of bone resorption in postmenopausal women

Adding three servings of yogurt to the daily diet of older women with habitually low calcium intakes resulted in a significant reduction in urinary excretion of N-telepeptide, a marker for bone resorption. Results were compared to the effects of three servings of a nutrition-poor snack and differences were apparent 7-10 days of starting the diet change. The satiety effect of the snacks resulted in a decrease in intake of other foods. The added nutrients of the yogurt improved overall diet quality substantially, while diet quality declined with the nutrient-poor snack. The results show that diets low in dairy intake are often marginal for several nutrients and that, so far as calcium is concerned, bone makes up for what the diet lacks. Moreover, bone resorption responds rapidly and sensitively to improvements in calcium intake that are readily achievable by an older female population.

Decline in muscle mass with age in women: a longitudinal study using an indirect measure

Muscle mass is known to decline with age, but only limited longitudinal data exist to quantify the rate of loss. Using 24-hour urine creatinine, corrected for the contribution of dietary meat intake, we assessed the change with age prospectively in 107 women who provided a minimum of 3 sets of measurements spanning an average interval of 11.9 years, centered around age 55 years. The rate of change in 24-hour urine creatinine at that age averaged -0.94%/yr (95% confidence interval [CI], -1.24% to -0.64%/yr; P <.001). Change in creatinine excretion was directly correlated with change in weight (P <.01), with those gaining weight tending to gain both lean and fat mass. The rate of change in creatinine excretion with age in our subjects is similar to that described in published cross-sectional studies on age-related change in total body potassium and in longitudinal studies using (40)K and dual-energy xray absorptiometry. Our study is the largest longitudinal study reported to date and provides, perhaps, a more secure basis for estimating muscle mass change with age than has been available heretofore.

Carbonated beverages and urinary calcium excretion

BACKGROUND

Intake of carbonated beverages has been associated with increased fracture risk in observational studies. The usual explanation given is that one or more of the beverage constituents increase urinary calcium.

OBJECTIVE

We assessed the short-term effects on urinary calcium excretion of carbonated beverages of various compositions.

DESIGN

An incomplete random block design was used to study 20-40-y-old women who customarily consumed > or =680 mL carbonated beverages daily. Four carbonated beverages were tested: 2 with caffeine and 2 without. Two contained phosphoric acid as the acidulant and 2 contained citric acid. The study included one neutral control (water) and one positive control (skim or chocolate milk). Serving size was 567 mL for the carbonated beverages and water and 340 mL for the milks. Beverages were consumed with a light breakfast after an overnight fast; no other foods were ingested until urine collection was complete. pH, titratable and total acidity, sodium, creatinine, and calcium were measured in 2-h (morning) fasting and 5-h postbeverage urine specimens.

RESULTS

Relative to water, urinary calcium rose significantly only with the milks and the 2 caffeine-containing beverages. The excess calciuria was approximately 0.25 mmol, about the same as previously reported for caffeine alone. Phosphoric acid without caffeine produced no excess calciuria; nor did it augment the calciuria of caffeine.

CONCLUSIONS

The excess calciuria associated with consumption of carbonated beverages is confined to caffeinated beverages. Acidulant type has no acute effect. Because the caffeine effect is known to be compensated for by reduced calciuria later in the day, we conclude that the net effect of carbonated beverage constituents on calcium economy is negligible. The skeletal effects of carbonated beverage consumption are likely due primarily to milk displacement.

Calcium intake and body weight

Five clinical studies of calcium intake, designed with a primary skeletal end point, were reevaluated to explore associations between calcium intake and body weight. All subjects were women, clustered in three main age groups: 3rd, 5th, and 8th decades. Total sample size was 780. Four of the studies were observational; two were cross-sectional, in which body mass index was regressed against entry level calcium intake; and two were longitudinal, in which change in weight over time was regressed against calcium intake. One study was a double-blind, placebo-controlled, randomized trial of calcium supplementation, in which change in weight during the course of study was evaluated as a function of treatment status. Significant negative associations between calcium intake and weight were found for all three age groups, and the odds ratio for being overweight (body mass index, >26) was 2.25 for young women in the lower half of the calcium intakes of their respective study groups (P: < 0.02). Relative to placebo, the calcium-treated subjects in the controlled trial exhibited a significant weight loss across nearly 4 yr of observation. Estimates of the relationship indicate that a 1000-mg calcium intake difference is associated with an 8-kg difference in mean body weight and that calcium intake explains approximately 3% of the variance in body weight.

Bioavailability of the calcium in fortified soy imitation milk, with some observations on method

BACKGROUND

Calcium-fortified soy milk is growing in popularity, particularly among vegetarians, but the bioavailability of its calcium was not previously known. Additionally, the validity of isotopic labeling methods for fortified liquid products had not been established.

OBJECTIVES

The objectives of this study were to compare the bioavailability of the calcium in fortified soy milk with that of calcium in cow milk and to evaluate the method of labeling soy milk for bioavailability testing.

DESIGN

A within-subject comparison of extrinsically labeled cow milk with intrinsically and extrinsically labeled soy milks was undertaken in 16 healthy men. In all tests, 300-mg Ca loads were given as a part of a light breakfast after an overnight fast. The milks were physically partitioned into liquid and solid phases to enable evaluation of tracer distribution.

RESULTS

Calcium from intrinsically labeled soy milk was absorbed at only 75% the efficiency of calcium from cow milk. Extrinsic labeling of soy milk did not produce uniform tracer distribution throughout the liquid and solid phases and resulted in a 50% overestimate of true absorbability.

CONCLUSION

Calcium-fortified soy milk does not constitute a calcium source comparable to cow milk, and extrinsic labeling of such calcium particulate suspensions does not produce the uniform tracer distribution needed for bioavailability testing. Hence, intrinsic labeling of the fortificant is required for such liquid suspensions.