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Biomedical subjects

W T Trouerbach

Publications and source records attributed to W T Trouerbach.

15 recordsLinked to original sources
PubMed1995

Calcium and magnesium in human toenails do not reflect bone mineral density.

Nail mineral composition is influenced by several physiological and pathological processes. Potentially, nails could be used to monitor alterations in the level of incorporation of specific elements produced by nutritional abnormalities, disease states or chronic exposure to toxic agents. The purpose of this study was to investigate whether the calcium and magnesium content in nail clippings, as measured by instrumental neutron activation analysis (INAA), correlates with bone mineral density (BMD), as measured by quantitative microdensitometry (QMD), and therefore could be interesting as a screening instrument for osteoporosis. The study involved 220 women, who participated in a breast cancer screening project (the DOM-project) in Utrecht, the Netherlands. The correlations found between Ca and Mg measurements and bone mineral densities were very low (correlation coefficients ranging from 0.03 to 0.18). It is concluded that Ca and Mg measurements in nail clippings by INAA cannot be used for screening purposes in the prevention of osteoporosis.

Adult↗
PubMed1995

Physical activity, calcium intake, and bone mineral content in children in The Netherlands.

STUDY OBJECTIVE: To examine the relation between physical activity, calcium intake, and bone mineral content in children. DESIGN: Population based, cross sectional study. SETTING: Primary schools in Zoetermeer, The Netherlands. PARTICIPANTS: Altogether 1359 Dutch boys and girls, aged 7 to 11 years (response rate 88%). MEASUREMENTS: Bone mineral content was measured by quantitative roentgen microdensitometry of the midphalanx of the second digit at the diaphyseal and metaphyseal site. Maximal exercise testing, according to the Bruce treadmill protocol, was used to assess physical fitness. Habitual physical activity was assessed by use of a questionnaire on physical activities. Daily calcium intake from dairy products was estimated by use of a semiquantitative food frequency questionnaire. MAIN RESULTS: Bone mineral content in boys was not linearly associated with physical fitness after adjustments for differences in height, body weight, chronological age, and skeletal age. In girls a linear association was found at the metaphyseal site only. When extreme groups were compared, bone mineral content was found to be higher in "high fitness children" (upper decile) than "low fitness children" (lowest decile), with statistical significance reached in boys only. When analyses were performed in subgroups of skeletal age, a clear linear relation between physical fitness and bone mineral content was seen in the mature subgroup in both boys and girls. No linear association was found between habitual physical activity and bone mineral content, while the results in extreme groups (that is, upper versus lowest decile) and in subgroups of skeletal age were comparable to those on physical fitness in boys only. No association was found between daily calcium intake and bone mineral content in this age group. CONCLUSIONS: This cross sectional study in children aged 7 to 11 years suggests that an increased bone mineral content is found only in those with a high level of physical activity. This association is most pronounced in the more mature children. No evidence was found for an association between daily calcium intake and bone mineral content in childhood.

Age Determination by Skeleton↗
PubMed1993

Cross-sectional and longitudinal study of age-related phalangeal bone loss in adult females.

To establish a comprehensive model for peripheral phalangeal bone loss, bone mass was studied in 1984 and 1989 using quantitative microdensitometry (QMD) in a total of 330 healthy women (age range 43-78.7 years). Bone mass and changes in bone mass were analyzed in relation to age and menopausal status. Ideal and nonideal populations were distinguished to assess the effect of diseases and medication. Both groups showed a decrease in bone mass, which proved to be more dependent on menopausal status than on age. A substantial loss started in the ideal group in the early postmenopausal period and in the nonideal group in the premenopausal period. Because the nonideal group started to lose bone at an earlier stage, the lifetime risk for osteoporosis is higher than in the ideal group.

Adult↗
PubMed1991

Determinants of bone mineral content in childhood.

In a sample of 1190 children (574 boys and 616 girls), aged 6.8-10.7 years, bone mineral content was studied using quantitative röntgen microdensitometry (QMD) at the diaphyseal and the metaphyseal site of the left second digit. Percentile curves of bone mineral density was determined by skeletal age for boys and girls separately. Bone mineral content at the diaphyseal site was significantly associated with skeletal age, height and body weight in boys and girls and with chronological age at the metaphyseal site in boys. In girls higher levels of bone mineral content were observed in those with a skeletal age greater than 7.3 years, compared to those with a skeletal age equal to or less than 7.3 years, adjusted for height and body weight. In boys a higher level of bone mineral content was found in those with a height greater than 138 cm, adjusted for skeletal age, compared to those with a height equal or less than 130 cm, at the diaphyseal and metaphyseal site. Girls with a relatively higher body weight had lower levels of bone mineral content at the metaphyseal site.

Age Determination by Skeleton↗
PubMed1990

Evaluation of postprocessing dual-energy methods in quantitative computed tomography. Part 1. Theoretical considerations.

Five postprocessing methods for dual-energy quantitative computed tomography of the vertebral body were evaluated theoretically. The methods were compared by transforming the original sets of equations to a standard set. Only two of these methods produced optimal results, namely the basic approach of Goodsitt et al and the method of Nickoloff et al. The calibration approach of Goodsitt et al will produce optimal results only if calibration materials are available that mimic the anatomic constituents of the vertebral body better than those available currently. Theoretically, the methods of Cann et al and of Laval-Jeantet et al will not produce optimal results.

Bone Density↗
PubMed1990

Evaluation of postprocessing dual-energy methods in quantitative computed tomography. Part 2. Practical aspects.

Three facets of dual-energy quantitative computed tomography are studied: (1) the algorithm for postprocessing data (the methods of Cann, Laval-Jeantet et al, Goodsitt et al [two methods], and Nickoloff et al); (2) the influence of choice of tissue-equivalent materials for calibration; and (3) the difference between central and peripheral calibration. The different tissue-equivalent materials include bone mineral-equivalent (K2HPO4 solutions and calcium hydroxyapatite), fat-equivalent (liquid paraffin, polyethylene, and 70% ethanol solution), and red marrow-equivalent (plastic). Deviation from the manufacturer's quoted content is least with central positioning of the calibration materials. The accuracy of estimates is best when the same tissue-equivalent materials are used for calibration that are being measured. The deviations produced by the use of different tissue-equivalent materials indicate the importance of using materials that mimic the components of bone most closely. The two methods of Goodsitt et al and the method of Nickoloff et al produced the best results.

Algorithms↗
PubMed1989

Noninvasive axial and peripheral assessment of bone mineral content: a comparison between osteoporotic women and normal subjects.

We compared different methods of bone densitometry in women with spinal osteoporosis and normal subjects to assess their discriminatory capability. The methods used included: quantitative computed tomography of the spine (QCT) specified as to trabecular (QCTtrab) and cortical bone (QCTcort), dual-photon absorptiometry of the spine (DPAspine), single-photon absorptiometry of the distal and proximal forearm (SPAdist and SPAprox), and quantitative roentgen microdensitometry of the phalanx (QMD). A total of 25 postmenopausal osteoporotic women and 24 healthy comparison subjects matched for age and years since menopause were studied. In the osteoporotic group an average decrement of the axial bone mineral density of -50% (p less than 0.001) and -20% (p less than 0.001) were observed for QCTtrab and QCTcort, respectively. For DPAspine, SPAdist, SPAprox, and QMD the difference between normal and osteoporotic subjects was -20% (p less than 0.001), -12% (p less than 0.05), -7% (NS), and -6% (NS), respectively. With the peripheral measurements (SPA and QMD), alone or in combination, no adequate discrimination between women with or without vertebral compression fractures could be obtained. Although QCTtrab showed the highest diagnostic sensitivity (81%), it appears not to be superior to DPAspine. Combinations of the various axial and peripheral measurements did not result in an essentially better sensitivity. In normal women as well as in osteoporotic individuals the trabecular and cortical QCT measurements showed two opposite trends, suggesting an increase in cortical and a decrease in trabecular density from L1 to L3.

Absorptiometry, Photon↗
PubMed1988

A cross-sectional study of age-related loss of mineral content of phalangeal bone in men and women.

The bone mineral content of the second phalanx of the second digit was studied by quantitative microdensitometry. It is concluded that age-dependent loss of bone is a generalised phenomenon in men and women that occurs at different rates at different ages. In women, an accelerated rate of bone loss is observed between 50 and 57 years of age; in men such an acceleration is observed after 68 years of age. It appears that in a selected "ideal" population (with no disease or medication that may influence bone metabolism) the rate of bone mineral loss in women of 50-57 years of age is greater than in an unselected normal population. Furthermore, especially in the 50-57 years age group, the rate of loss at the mid-shaft of the phalanx in women is higher than at a site 25% from the proximal end. In men the rate of bone mineral loss at the 25% site exceeds that at midshaft, especially in the 68-75 year age group.

Absorptiometry, Photon↗
PubMed1987

Microdensitometric analysis of bone structures in X-ray images.

The careful evaluation of bony structure is important in the study of normal bone and bone disorders. This study describes bony structure as seen in the X-ray pattern of the phalanges of the hand using quantitative microdensitometry. Normalised scans of bony density show the regular and irregular distribution of the trabeculae. Two properties were determined from these densitometric findings: the mean transverse coarseness (C) indicating fluctuations of horizontal density and the overall standard deviation indicating axial homogeneity (H). This investigation demonstrates the applicability of the method: it shows a significant correlation with radiological diagnosis and that microdensitometry is a reliable method for quantifying the coarseness and homogeneity of bone structure.

Bone and Bones↗
PubMed1987

A study on the phalanx bone mineral content in 273 normal pre- and post-menopausal females (transverse study of age-dependent bone loss).

Quantitative Röntgen microdensitometry (QMD) can be used to provide a precise quantification of mean specific bone mass (rho) from standardized radiographs. The method is simple, non-invasive, low in cost and suitable for frequent repetition. Bone mineral mass at the mid-length (largely cortical bone) of the middle phalanx of digital II of the left and right hands was investigated. Normalized quantification of bone structure can be achieved with a precision (coefficient of variation) of the order of 1%. Rho values were determined for the right and left phalanx in 273 apparently healthy women 43-73 years of age (mean menopausal age, 49.8 years) in an attempt to differentiate between normal changes with age and excessive bone mineral loss. The mean rate of age-dependent bone mineral loss was -1.4% per year in pre-menopausal women; in post-menopausal women between 50 and 57 years it was -3.5% per year and between 58 and 73 years it was -0.8% per year. The mean rate of change of bone mineral mass in the same group, as a function of the number of years after menopause, was -1.9% per year for the group 2-8 years after menopause and +0.1% per year for the group 9-20 years after menopause.

Adult↗
PubMed1985

Roentgendensitometric study of the phalanx.

This is an outline of a radiologic assessment of bone mineral measurements for diagnosis that is simple and low in cost. Bone mineral content equivalent values (BMCE) were determined of phalanges. Since phalanges have different dimensions the BMCE values per square millimeter surface area, bone mean mineral equivalent values (BMME) were determined. In normal subjects it was shown that over a period of 9 months a coefficient of variation for BMCE and BMME was found of 8 and 9%, respectively, indicating a change during the investigation period (precision of the technique has a CV for BMCE of 4% and for BMME of 3%). The clinical application of microdensitometry and of the single photon absorption method was tested and compared. Both methods resulted in similar findings, microdensitometry however also provides a qualitative assessment of bone characteristics.

Absorptiometry, Photon↗
PubMed1984

A study of the radiographic aluminum equivalent values of the mandible.

A longitudinal study of bone changes in the mandible was conducted. Duplicate radiographs were taken at 3-month intervals with the use of a positioning instrument, which included an aluminum calibrating wedge. The in-duplicate values obtained over the investigation period made it possible to assess the precision of the method and to analyze effects that take place with time. Significant bone changes were observed in seven volunteers between various observation periods at intervals of 6 and 9 months.

Absorptiometry, Photon↗