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PubMed1998

Women's decisions about hormone replacement therapy after education and bone densitometry.

BACKGROUND: The decisions that postmenopausal women make about whether to start hormone replacement therapy may depend on the potential risks and benefits of such therapy as well as their risk for osteoporosis-related fractures. This study examined the decisions made by women at risk for osteoporosis-related fractures who were educated about hormone replacement therapy and who were given information about their bone mineral density. METHODS: The study employed a prospective cohort design. Thirty-seven post--menopausal women with risk factors for osteoporosis-related fractures were recruited from an orthopedic clinic at a teaching hospital in Hamilton, Ont. The women were given an education kit (consisting of an audio tape and a work-book) to clarify the benefits and risks of hormone replacement therapy. Two to 4 weeks later, densitometry of the hip and the lumbar spine was performed. A summary of the risks, the densitometry findings and decisions about hormone replacement therapy were given to the women's family physicians for follow-up. Outcome measures included decisions about hormone replacement therapy, as well as use of such therapy and other medications at 12 months. RESULTS: After the education component alone, 10 (27%) of the women requested hormone replacement therapy. After densitometry testing, 4 more requested hormone replacement therapy (for a total of 14 women [38%]). At 12 months, 2 (5%) of the women had been lost to follow-up. Of the remaining 35, 6 (17%) were receiving hormone replacement therapy, 7 (20%) were using bisphosphonates, and 24 (68%) were taking calcium supplements. INTERPRETATION: These preliminary findings suggest that the combination of education about hormone therapy and feedback about bone density is associated with an increase in the use of hormone replacement therapy and other preventive medications by women at risk for osteoporosis-related fractures. However, the observed increase was small and so the clinical significance must be confirmed and clarified.

Absorptiometry, Photon↗
PubMed1990

Color matching and foveal densitometry in patients and carriers of an X-linked progressive cone dystrophy.

We describe a family with an as yet undescribed form of X-linked progressive cone dystrophy in a five-generation pedigree, from which we report here the results of 17 male patients and 31 obligate and 13 possible female carriers. The affected males showed the characteristic picture of cone dystrophy. Foveal cone photopigment density was impaired (judged from anomaloscope settings and foveal densitometry), even at an early stage of the disease. The carriers showed no fundus abnormalities, except occasional changes due to myopia. The anomaloscope demonstrated mild pseudoprotanomaly in 27 of 31 obligate carriers and in six of 13 possible carriers. Foveal densitometry findings performed in 11 carriers always agreed with the anomaloscope findings. We conclude that the findings of pseudoprotanomaly and abnormal density differences in females of this family were the only ocular abnormalities and thus are indicative of the carrier state.

Adult↗
PubMed1990

Quantitative densitometry from the point of view of information theory.

The process of quantitative densitometry is analyzed with methods developed in information theory. It is shown that the steps involved in densitometry, e.g. gel staining, mechanical, optical and electronic processing, as well as all the steps of data processing, can be viewed as communication channels. The factors affecting both the relevant and irrelevant part of the total information passed through these channels are discussed in the consistent frame provided by information theory. This view leads to a unifying context for analyzing the performance of quantitative densitometers.

Densitometry↗
PubMed1990

Electrophoretic separation of nucleic acids: evaluation by video and photographic densitometry.

The separation of DNA by gel electrophoresis provides a rapid method for determining size distributions of DNA in solution. Densitometric scanning of photographs of gels has been the standard method of analysis of agarose gels. However, analysis of photographs is complicated by the non-linear response of photographic film. Charged-coupled device video cameras have become popular for quantitative densitometry and we have used a charge-coupled device camera to image agarose gels to quantitate DNA damage. We compare video and photographic densitometry for quantitation of ultraviolet radiation (UV)-induced DNA damage and find that the two methods give equivalent results.

DNA↗
PubMed1997

Quantitative densitometry of proteins stained with coomassie blue using a Hewlett Packard scanjet scanner and Scanplot software.

In the present study we evaluated the performance of a software/scanner system that employed the Hewlett Packard (HP) ScanJet Plus and Scanplot Software for densitometric quantification of protein loads stained with Coomassie Brilliant Blue following sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Gels with bovine serum albumin (BSA) standards, ranging from 0.125 to 10 micrograms, were scanned using reflectance densitometry with 127 microns step size in both the x and y directions and a resolution of 200 dots per inch. Densitometric volume was calculated for each protein band from scanner output in the tagged image file format (TIFF) by a customized software package, Scanplot V. 4.05 (Cunningham Engineering). Protein loads between 0.125 and 10.0 micrograms vs. volume were fit by a second-order regression: Volume = -0.58 x protein load2 + 16.82 x protein load + 7.87 (r = 0.991, p < 0.01). The same gels were scanned and quantified using a transmittance laser densitometer; densitometric volumes measured by both systems were highly correlated (r2 = 0.981, p < 0.01). Additional gels of BSA, smooth muscle myosin heavy chain (myosin), and actin displayed linear relationships between protein loads up to 4.0 micrograms and densitometric volume reflecting unique dye binding properties. We conclude that accurate and reproducible quantitative densitometry of SDS-PAGE can be performed using the HP ScanJet Plus scanner and Scanplot software.

Actins↗
PubMed2001

A quantitative histochemistry technique for measuring regional distribution of acetylcholinesterase in the brain using digital scanning densitometry.

Studies of brain acetylcholinesterase (AChE) are traditionally based on biochemical assays, immunoreactivity, and histochemistry. Conventional histochemistry yields rich morphological data from tissue sections but yields quantitative results only with great difficulty. Several histochemical methods developed in recent years, including microdensitometry, microphotometry, and video-based histochemistry, are effective in quantitative and detailed study of AChE in tissue sections. However, they are usually time-consuming. As we report here, we adapted digital scanning densitometry to quantitate AChE histochemical staining in brain sections. The AChE and butyrylcholinesterase (BuChE), as measured by the method, were heterogeneously distributed throughout the brain, results that are consistent with those obtained by biochemical methods. The staining intensity is dependent on section thickness, substrate concentration, and reaction time. The cholinesterase inhibitor methyl paraoxon significantly decreased AChE staining intensity. Furthermore, data acquired from densitometry are similar to those obtained by video-based microscopy or by spectrophotometry. The advantage of the densitometric measurements compared to other quantitative histochemical methods is that it is very rapid while collecting data that are equivalent in quality. Because the digital scanning densitometers provide high quality and sensitive imaging, wide dynamic ranges, and convenient image analysis software, they are very useful tools in quantitative histochemistry.

Acetylcholinesterase↗
PubMed2005

[Clinical study of acoustic densitometry technique in detecting atherosclerotic plaque].

OBJECTIVE: To investigate the effect of Quyu Xiaoban Capsule (QYXB) on the regressive treatment of atherosclerosis (AS) with acoustic densitometry (AD) technique. METHODS: Eighty patients with AS were randomly divided into two groups, trial group was treated with QYXB and conventional medicine, and control group was treated with conventional medicine alone. Normal arterial wall and different types of atherosclerotic plaques were detected with AD technique before treatment and 10 months later. RESULTS: The corrected averages in intimal echo intensity (AIIc%) were elevated in both groups but without significant difference, AIIc% of fatty plaques were increased in both groups and the value after treatment was significantly higher than that of pre-treatment in the trial group (68.12 +/- 5.54 vs 61.43 +/- 5.37, P < 0.05). The increment rate of AIIc% in trial group was significantly higher than that in control group (10.9 +/- 5.1% vs 2.5 +/- 5.5%, P < 0.05). CONCLUSION: QYXB can stabilize the atherosclerotic plaque by increasing its acoustic density. Acoustic densitometry technique can differentiate the different histological plaques and monitor the histological changes of plaques during treatment.

Adult↗
PubMed2004

Perioperative monitoring of circulating and central blood volume in cardiac surgery by pulse dye densitometry.

OBJECTIVE: To determine perioperative changes in circulating (BVI) and central blood volume (CBVI) by a new dye dilution technique using pulse dye densitometry. DESIGN AND SETTING: Prospective observational study in the cardiac anesthesia and intensive care unit of a university hospital. PATIENTS: Sixty-six patients undergoing coronary artery bypass surgery. MEASUREMENTS AND RESULTS: Hemodynamic measurements by the dye dilution method using pulse dye densitometry were performed prior to skin incision and 3.3+/-1.4 h and 17+/-2.7 h after surgery. Based on conventional monitoring the therapeutic goals of hemodynamic therapy were achieved in all of the patients of this study. Despite a marked positive fluid balance which developed during surgery mean BVI decreased significantly after surgery while CBVI remained unchanged. Postoperative BVI deficits vs. preoperative values were observed in 78% of patients; these BVI deficits were profound in 29% of the cases. In contrast, 65% of the individual patients showed no or only minor postoperative changes in CBVI vs. preoperative values. CONCLUSIONS: Changes in the intravascular volume compartments affected BVI to a greater extent than CBVI. Therefore measuring circulating in addition to central blood volume may be useful to ensure a normal circulating blood volume that can compensate for any change in the central vascular compartment.

Analysis of Variance↗
PubMed2004

Special report on the official positions of the International Society for Clinical Densitometry.

The International Society for Clinical Densitometry (ISCD) periodically holds Position Development Conferences (PDCs) for the purpose of establishing standards and guidelines for indications, acquisition, and interpretation of bone density tests. Topics are selected for consideration by the ISCD Scientific Advisory Committee, reviewed by scientific working groups, and presented to an international panel of experts. Topic categories addressed to date include indications for bone density testing, selection of reference databases for T-scores and Z-scores, clinical applications for central and peripheral bone densitometry, serial bone density testing, instrument precision assessment, phantom scanning and calibration testing, requirements for a bone density report, nomenclature, and diagnosis of osteoporosis in postmenopausal women, premenopausal women, men, and children. Following an open session for public comment and discussion, the panel convenes for consideration of each topic and makes recommendations for positions to the ISCD Board of Directors. Recommendations that are accepted become the Official Positions of the ISCD. This Special Report summarizes the methodology of the ISCD PDCs and presents selected Official Positions of general interest.

Absorptiometry, Photon↗
PubMed2001

Identifying bone-mass-related risk factors for fracture to guide bone densitometry measurements: a systematic review of the literature.

Available evidence suggests that fracture prediction with bone densitometry may improve when used on people at high risk of osteoporotic fractures. The objectives of this literature review were: (1) to identify risk factors for fracture that are associated with the development of a low bone mass for both men and women; (2) to describe and assess the relationship between these factors and the risk of fracture; and (3) to classify them according to the strength of their association with fracture incidence. Studies were identified from MEDLINE (1982-1997), HealthSTAR (1975-1997) and The Cochrane Library (1997) databases. Pre-stated inclusion criteria (original analytic studies assessing risk factors for osteoporotic fractures in men and women) and methodologic quality were assessed by two independent investigators. Information on the study design and analysis, characteristics of participants, exposure (risk factor) and outcome measures (relative risk and odds ratios for fracture incidence), control for potential confounding factors and risk estimates was extracted using a standardized protocol. Qualitative and meta-analytic techniques were used for data synthesis. As a result, risk factors were classified into three groups according to their strength of association with fracture: high risk (RR > or = 2), moderate risk (1 < RR < 2) and no risk or protective (RR < or = 1). Of approximately 80 risk factors identified from 94 cohort and 72 case-control studies, 15% were classified in the high-risk group, including low body weight, loss of weight, physical inactivity, the consumption of corticosteroids or anticonvulsants, primary hyperparathyroidism, diabetes mellitus type 1, anorexia nervosa, gastrectomy, pernicious anemia, and aging (> 70-80 years). Eighteen percent and 8% of risk factors were classified in the moderate and no risk group respectively, whereas 60% showed either a lack of scientific evidence confirming their association with fracture or contradictory results. An efficient strategy for bone densitometry provision may thus be its selective use in those individuals who present with several strong or moderate risk factors for fracture related to bone mass loss.

Adrenal Cortex Hormones↗
PubMed2000

Ultrasound bone densitometry of the os calcis in children and adolescents.

The aim of the present investigation was to evaluate reference data and to examine whether there were weight-, height-, age-, and sex-related differences of the quantitative ultrasound bone parameters for healthy children and adolescents. A total of 3299 healthy Caucasian children and teenagers (1623 girls and 1676 boys), age range from 6-18 years (mean age 11.4 +/- 3.4 years for boys and mean age 11.5 +/- 3.3 years for girls) were examined by quantitative ultrasound densitometry (QUS) using the bone sonometer SAHARA (Hologic Inc., Waltham, MA, USA), a waterless, dry system. The parameters broadband ultrasound attenuation (BUA) [dB/MHz] and speed of sound (SOS) [m/second] were evaluated on the right heel in relation to age, sex, weight, and height. There is no correlation between the ultrasound bone parameter SOS and age, height, and weight. BUA increases with age, height, and weight. Significant differences in SOS and BUA between girls and boys were found to probably be caused by the different onset of growth phases and the onset of puberty. SOS and BUA are influenced by changes of bone mineral density. But BUA is dependent on bone size, too. In conclusion, ultrasound bone densitometry is a useful measuring method showing the physiological bone development in childhood and adolescence. The presented results can be used as reference data. Further studies in children with disorders influencing bone metabolism will show in what way various patterns of osteopenia in childhood can be detected.

Adolescent↗
PubMed1999

Ultrasound densitometry of the os calcis in patients with hemiparesis following a cerebrovascular accident.

Ultrasound densitometry has been measured in the os calcis of 31 stroke patients (14 women, 17 men), ages 46-87 years, to determine whether bone density is lower than expected for normal subjects at this site, and to investigate whether or not the stroke side has lower values than the nonstroke side. We have also measured a large control group of 268(39 men, 228 women) subjects who showed similar values to other published data. Immobility is a known precursor to bone loss and so we also compared ultrasound Stiffness Index with an index of mobility in 22 of the stroke patients. In healthy subjects, ultrasound densitometry (measured as Stiffness) fell by 25% in females from 48-52 to 68-72 years. Stiffness (expressed as z-score) in patients with stroke was low in females (P < 0.02) but not in males, but both stroke side and nonstroke side were equally low. Stiffness did not decline with time since stroke, but did correlate with mobility after stroke, on the stroke (r = 0.73) and nonstroke (r = 0.62) side. The data suggest that stroke patients, particularly females, have low bone density before the stroke event. The greater ultrasound Stiffness with increasing mobility after stroke may suggest that active rehabilitation after stroke may produce denser bone.

Activities of Daily Living↗
PubMed2006

Early detection of liver failure after hepatectomy by indocyanine green elimination rate measured by pulse dye-densitometry.

BACKGROUND/PURPOSE: Following a major hepatectomy, some degree of clinical and biochemical dysfunction occurs. Surgeons usually check serum total bilirubin levels to diagnose postoperative liver dysfunction. However, we cannot predict liver failure by biochemical data alone within the early postoperative period. Using newly developed pulse dye-densitometry (PDD), we measured serial postoperative indocyanine green elimination rate (ICG-K) values and investigated the possible relation between postoperative ICG-K values and complications. METHODS: Fifty-one patients scheduled for hepatectomy between January 2000 and December 2002 were enrolled. Pulse-dye densitometry was used to evaluate postoperative liver function. We analyzed the relation between postoperative ICG-K and postoperative outcome, assessed in terms of morbidity and mortality. RESULTS: Liver failure was seen in seven patients. The ICG-K value on postoperative day 1 in patients with liver failure was significantly lower than that in patients without liver failure (0.070 +/- 0.018 vs 0.152 +/- 0.056/min respectively; P < 0.001). There were no differences between preoperative ICG-K values in patients with and without liver failure. The sensitivity and specificity of an ICG-K value of less than 0.07 on postoperative day 1 were 71.4% and 95.5%, respectively, for predicting liver failure. CONCLUSIONS: We can measure the ICG-K value by PDD at the bedside without time delay, and we can predict liver failure in the early postoperative period by the ICG-K values on postoperative day 1. ICG-K values measured by PDD can provide important information for perioperative management.

Adult↗
PubMed2005

Determination of the standard value of circulating blood volume during anesthesia using pulse dye-densitometry: a multicenter study in Japan.

PURPOSE: The standard value for circulating blood volume (BV) during anesthesia was determined by a multicenter study in Japan. The significance of BV on the reduction of blood pressure after the induction of anesthesia was also examined. METHODS: The study included 184 patients from eight university hospitals. After the induction of anesthesia, pulse dye-densitometry was performed according to a uniform protocol. Factors contributing to reduced blood pressure after induction of anesthesia were examined by multiple logistic regression analysis. RESULTS: The mean and standard deviation of BV was 80.0 +/- 13.9 ml x kg(-1); for females and 84.2 +/- 15.3 ml x kg(-1) for males (P > 0.05). There was no age difference in terms of BV. After adjusting for the effects of height, weight, and age, the factors predisposing to a reduction in blood pressure of >20 mmHg after induction of anesthesia were found to be age (P < 0.01) and BV (ml x kg(-1)) (P < 0.001). CONCLUSION: We determined the BV of anesthetized patients before surgery in Japan using pulse dye-densitometry. It is suggested that age is not a factor regarding BV, and that blood pressure tends to be reduced in hypovolemic patients after induction of anesthesia.

Adult↗
PubMed2007

Bone biopsy and densitometry findings in a child with Camurati-Engelmann disease.

Progressive diaphyseal dysplasia (MIM 131300), also known as Camurati-Engelmann disease (CED), is a rare autosomal dominant craniotubular dysplasia caused by mutations in the transforming growth factor beta1 (TGF-beta1) gene. Radiographs of the long bones of a 9-year-old boy presenting with waddling gait, muscular weakness, underweight, and severe skeletal pain showed symmetric diaphyseal cortical thickening pathognomonic for CED. The diagnosis was verified by detecting a mutation in exon 4 of the TGF-beta1 gene. Full body bone mineral densitometry studies performed before treatment with prednisolone were indicative for osteoporosis (Z-scores for the lumbar spine and femoral neck -2.3 and -3.2, respectively). A transiliac bone biopsy showed markedly reduced trabecular bone volume. Oral prednisolone was initiated, and subsequently, pamidronate infusions were commenced in an attempt to prevent progression of osteoporosis. To our knowledge, this is the first time bone biopsy and bone mineral densitometry studies have been performed and bisphosphonate treatment evaluated in a child with CED.

Biopsy↗
PubMed1983

Thin-layer chromatography-densitometry of minor acidic phospholipids: application to lipids from erythrocytes, liver, and kidney.

A method for quantitative determination of acidic phospholipids by thin-layer chromatography (TLC) followed by densitometry is described. The total lipids were separated into neutral and acidic fractions by DEAE-Sephadex column chromatography. A clear-cut separation of acidic phospholipids was achieved by high-performance TLC with a solvent system of chloroform/acetone/acetic acid/formic acid/water (60/60/4/10/3). Each phospholipid band was quantitated by densitometry with the use of an internal standard. The lipid compositions of sheep and mouse erythrocytes and of rat liver and kidney were determined by the present method.

Animals↗
PubMed1986

Low-cost two-dimensional gel densitometry.

A major obstacle to full utilization of the powerful technique of two-dimensional (2-D) gel electrophoresis is the expense and complexity of quantifying the results. Using an analog-to-digital converter already present in the widely available Commodore 64 or Commodore 128 microcomputer, we have developed a 2-D gel densitometer (GELSCAN) which adds only $20.00 to the cost of the Commodore system (currently around $700.00). The system is designed to work with autoradiograms of 2-D gels. Spots of interest are identified visually and then positioned manually over a light source. A pinhole photoelectric sensor mounted in a hand-held, Plexiglas holder, or "mouse," is briefly rubbed over each spot. Maximum density of the spot is determined and its value is converted to counts per minute via an internal calibration curve which corrects for the nonlinear response of film to radiation. Local spot backgrounds can be subtracted and values can be normalized between gels to adjust for variation in amount of radioactivity applied or in exposure time. Reproducibility is excellent and the technique has some practical as well as theoretical advantages over other more complicated approaches to 2-D gel densitometry. In addition, the GELSCAN system can also be used for scanning individual bands in 1-D gels, quantitation of "dot-blot" autoradiograms and other tasks involving transmission densitometry.

Animals↗
PubMed1988

Transmission densitometry of stained nitrocellulose paper.

We report a simple solution to the problem of quantitative densitometry of stained nitrocellulose paper. By immersing the paper in a household lubricating oil of matching refractive index, the light-scattering properties of the paper are largely eliminated, allowing precise transmission densitometry in any flat bed densitometer. The method was evaluated on immunochemically stained Western blots of the proteinases cathepsins B and L. An approximately linear relationship was found between the integrated absorbance of the stained zone and the logarithm of the amount of protease applied to the polyacrylamide gel over the range of 150 to 350 ng of cathepsin B and 50 to 250 ng of cathepsin L.

Blotting, Western↗