Search PubMed⌕ Search

PubMed · 5245653

Radiography analysis by two-dimensional microdensitometry.

Abstract

The source did not provide an abstract. Follow the original record for more information.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

G Isenberg, H M Goldman, J Spira, F G Parsons, P N Street. 1968. Radiography analysis by two-dimensional microdensitometry.. https://doi.org/10.14219/jada.archive.1968.0351

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

The degree of mineralization of bone tissue measured by computerized quantitative contact microradiography.

Strength of bones depends on bone matrix volume (BMV), bone microarchitecture, but also bone mineralization, and we have recently shown in osteoporotic patients treated with alendronate that fracture risk and bone mineral density (BMD) were changed without modifications of BMV or bone microarchitecture. Mineralization of bone matrix implies two successive steps: a rapid primary mineralization on the calcification front followed by a slow process of secondary mineralization progressively adding about one-half of the mineral content on bone matrix. These two steps are clearly illustrated by microradiographs of compact and cancellous bone tissue from transiliac human biopsies. Our working hypothesis is based on the impact of changes in bone remodeling rate on the degree of mineralization of bone, i.e., on the BMD measured at the tissue level. Contact quantitative microradiography using a computerized microdensitometric method, is described and allows the measurement of the mean degree of mineralization of bone (MDMB). This parameter may be quantitatively evaluated by exposing an aluminum calibration step-wedge and a plane-parallel calcified tissue section simultaneously to the same beam of X-rays, then determining, from the resulting microradiograph, the thickness of aluminum that produces the same X-ray absorption as a given region of the bone tissue section. To be used as a control group, iliac bone samples were taken at necropsy from 43 subjects (30 women aged 48.4 +/- 3.7 years and 13 men aged 66.0 +/- 4.4 years) who died suddenly showing no apparent bone disease. A control MDMB, which does not change with age, and a control distribution of these values are thus established. These control values are necessary for interpreting the changes in MDMB observed in bone conditions untreated or treated.

Absorptiometry, Photon↗

Inverse relationship between the changes in trunk lean and fat mass during gonadotropin-releasing hormone agonist therapy.

OBJECTIVE: The aim of the present study was to investigate the relationship between the changes in lean and fat mass during gonadotropin-releasing hormone agonist (GnRH agonist) therapy. METHODS: Subjects were 24 premenopausal women (mean age, 39.5+/-9.4 years; range, 32-52 years) with uterine leiomyomas. They were given GnRH agonist (leuprorelin acetate, 3.75 mg) monthly for 4 months. Age and height were recorded. Body weight, regional and total body composition, and the ratio of trunk fat mass to leg fat mass (trunk-leg fat ratio) were assessed by whole body scanning with dual-energy X-ray absorptiometry. Changes in these variables were investigated. Relationships between the changes in regional lean and fat mass were investigated using Pearson's correlation test. RESULTS: Trunk fat mass significantly increased from 8616+/-3538 to 9265+/-3526 g (P<0.01) and trunk-leg fat ratio significantly increased (1.02+/-0.39 to 1.07+/-0.39, P<0.05). Trunk lean mass significantly decreased from 18,509+/-2602 to 17,916+/-2402 g (P<0.01). However, body weight, and lean and fat mass component in the extremities did not change. Change in trunk fat mass was inversely correlated with change in trunk lean mass (r=-0.439, P<0.05), but such relationships were not observed in arm and leg regions. CONCLUSION: Inverse relationship between the changes in trunk lean and fat mass is observed during GnRH agonist therapy.

Absorptiometry, Photon↗

Epidemiological evidence of increased bone mineral density in habitual tea drinkers.

BACKGROUND: Researchers have hypothesized that bone mineral density (BMD) may be influenced by chemical compounds such as caffeine, phytoestrogen, fluoride, and many compounds that are contained in tea extracts. Hence, the relationship between habitual tea consumption and BMD is an interesting issue. METHODS: Based on an epidemiological survey, we enrolled 497 men and 540 women, 30 years and older, in our study. All subjects were questioned about their habit of tea consumption and other lifestyle characteristics by means of a structured questionnaire. Dual-energy x-ray absorptiometry was used to measure the BMD of the total body, lumbar spine (L1-L4), hip neck, and Ward triangle regions. RESULTS: Five hundred two subjects (48.4%) were habitual tea drinkers, with a mean duration of tea consumption of approximately 10 years. Compared with nonhabitual tea drinkers, subjects with habitual tea consumption of 6 to 10 years showed higher lumbar spine BMDs, and those with consumption of more than 10 years showed the highest BMDs of all measured regions. Under the multiple stepwise regression models, sex, age, body mass index, total physical activity, and habit of tea consumption were the major significant variables for the different BMD regions. Regarding the behavioral characteristics of tea consumption, the duration of tea consumption was the only independent determinant for the BMDs. CONCLUSION: Habitual tea consumption, especially for more than 10 years, has significant beneficial effects on BMD of the total body, lumbar spine, and hip regions in adults.

Absorptiometry, Photon↗