Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Densitometry”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34Linked to original sources
PubMedDate not supplied

Osteoporosis and bone densitometry.

Osteoporosis, a clinically detectable decrease in bone density, affects 24 million Americans, placing them at increased risk for fractures. This article describes the anatomy and physiology of bones and the detection, treatment and prevention of osteoporosis. Techniques for bone densitometry are emphasized, including conventional radiography, single photon and single energy x-ray absorptiometry, dual photon absorptiometry, dual energy x-ray absorptiometry, quantitative CT and ultrasound.

Absorptiometry, Photon↗
PubMed1997

Classification strategies for the grading of renal cell carcinomas, based on nuclear morphometry and densitometry.

The various grading systems proposed for renal cell carcinomas all suffer from problems related to inter-observer variability. Some of these grading systems are based, either partially or wholly, on morphonuclear criteria, such as nuclear size and shape, anisonucleosis, and chromatin pattern. These criteria can be quantitatively (and thus objectively) evaluated by means of the computer-assisted microscopic analysis of Feulgen-stained nuclei. In the present work, 39 quantitative variables, including two morphometric, 28 chromatin pattern-related, and nine DNA ploidy level-related, were computed for 65 renal cell carcinomas. The actual diagnostic information contributed by each variable was determined by means of multifactorial statistical analysis (discriminant analysis) and two artificial intelligence-related methods of data classification (the decision tree and production rule methods). The results show that quantitative information, as provided by the computer-assisted microscopy of Feulgen-stained nuclei and analysed by means of artificial intelligence-related methods of data classification, contributes significant diagnostic information for the grading of renal cell carcinoma, thus reducing the problem of inter-observer reproducibility.

Adult↗
PubMed1980

Computerized densitometry and color coding of [14C] deoxyglucose autoradiographs.

A computerized image processing system has been developed for quantitative analyses of autoradiographs obtained with the [14C]deoxyglucose method. The system is composed of standard, commercially available components and includes a scanning microdensitometer, computer, image memory and display system, and monochrome and color monitors. The associated computer programs are written in PASCAL. Autoradiographs are automatically scanned, and the optical density of each spot is digitized at a maximum resolution of 65,536 readings per 6.4 x 6.4 mm area and stored in memory. Images can be reconstructed from the data in memory, displayed on the monitors, and utilized for microdensitometric analyses or manipulated for image enhancement, enlargement, or weighted averaging of selected regions. The digitized data can also be utilized to solve the operational equation of the [14C]deoxyglucose method, and color-coded images of autoradiographs can be reconstructed so that each color represents a narrow range of the rate of glucose utilization. By means of this system, it is possible to generate quantitative metabolic maps that display the distribution of actual rates of local glucose utilization throughout the entire central nervous system in regions as small as 100 micrometers or less.

Animals↗
PubMed1989

Vertical remission densitometry for the evaluation of nontransparent samples.

Gels dried onto filter paper or their blots on membranes are not suitable for densitometric evaluations in the transmission mode because these samples are nearly nontransparent. By scanning in the remission mode, evaluation with good results is possible. Data acquisition by a computer-controlled high speed scanning photometer and digital image processing affords a spatial resolution and accuracy similar to that in the transmission mode. The signal-to-background ratio decreases by 10-30% depending on the smoothness of the support.

Autoanalysis↗
PubMed1990

Degradation of individual intracellular proteins analyzed by two-dimensional gel electrophoresis and computerized video densitometry.

A technique is described for the analysis of degradation rates of individual intracellular proteins, based on pulse-chase-labeling of cells using radioactive amino acids [35S]methionine, two-dimensional polyacrylamide gel electrophoresis, fluorography and scanning of the fluorograms by a computerized video densitomter. As compared to scintillation counting of individual protein spots resolved by two-dimensional gel electrophoresis, this method allows a rapid and precise determination of the degradation rates of individual intracellular proteins. In the present study, degradation rates of individual intracellular proteins of normal human skin fibroblasts and skin fibroblasts from patients with Duchenne muscular dystrophy were compared. Rates of degradation for proteins PIIa, PIIb and PIIc recently described as cell-type-specific proteins were significantly enhanced (p less than 0.01) in fibroblast cultures of Duchenne muscular dystrophy origin.

Cells, Cultured↗
PubMed1991

Determination of rat plasma esterase-1 (ES-1) activity by scanning densitometry of gradient polyacrylamide gels with zymogram detection.

There is no specific assay for rat plasma esterase-1 (ES-1) activity. Plasma contains many esterases, while known substrates do not discriminate between esterases. With gel electrophoresis, plasma esterase isozymes can be separated. Thus, a method consisting of gradient polyacrylamide gel electrophoresis, visualization of the enzyme with a staining technique based on substrate conversion, and densitometric scanning of the stained gel has been developed for quantitative measurement of rat plasma ES-1 activity. ES-1 activities were expressed as total peak areas. Reproducibility of the method was found to be about 10% (expressed as apparent between-gel coefficient of variation). When the ES-1 zone areas was expressed relative to that of a plasma ES-1 standard, reproducibility was about 3%. The kinetics of catalysis of alpha-naphthyl acetate hydrolysis by ES-1 could be determined with the gel scanning assay; the Km was 0.76 mM. At the alpha-naphthyl acetate concentration of 2.69 mM, total peak areas of the ES-1 zone were linearly associated with the staining time (up to at least 40 min) and amount of plasma (up to 26.25 microL). The pH of the staining buffer influences the ES-1 zone area, the largest areas being obtained when the pH ranged between 7.0 and 7.8. With propionate as acyl moiety of the alpha-naphthyl ester substrate, ES-1 zone areas were higher than with either acetate, butyrate or hexanoate.

Animals↗