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PubMed1986

Reflective densitometry of Western blots to quantitate the developmentally regulated accumulation of myosin light chain 3.

We have employed a monoclonal antibody to fast myosin alkali light chains to study the accumulation of myosin light chain 3 (MLC3f) in the breast and limb musculature of developing quail embryos using quantitative densitometry of Western blots. Our analyses reveal that MLC3f is first detected in the breast muscle of 11 day embryos and accumulates at a constant rate until hatching at day 16. This data suggests, by extrapolation, that MLC3f accumulation is initiated at day 10 in embryonic breast muscle. MLC3f is also first detected in the limb muscle of 11 day embryos, but does not accumulate rapidly until after day 13. These results demonstrate the effective use of reflective densitometry in the study of developmental problems and in the quantitation of Western blots in general.

Age Factors↗
PubMed1986

A semi-automated system for quantitative densitometry of autoradiographs.

We describe a semi-automatic, computerized method of quantitative densitometry for regional analysis of whole brain autoradiographs. The technique features menu-driven software and verbal prompting for data via a speech synthesizer. Advantages over manual methods include an 80% reduction in the time required for data collection, easy retrieval and statistical analysis of data, and the production of a large data base for future use. The application of this system to the [14C]2-deoxy-D-glucose autoradiographic method for measurement of local cerebral glucose utilization is described. This system makes available computerized densitometry at a modest cost.

Animals↗
PubMed1996

Clarification of immunoblots on polyvinylidene difluoride (PVDF) membranes for transmission densitometry.

The opacity of polyvinylidene difluoride (PVDF) transfer membrane can be reduced by infiltration with liquid. A mixture of 9:1 v/v ethylene glycol/glycerol gives complete transparency; clarification by this mixture is stable due to the low volatility of the components and is reversed by washing in water without loss of band intensity. The mixture is easy to apply to the membrane and being water soluble, non-corrosive and relatively non-toxic, is convenient to use. Clarification and densitometric analysis of stained immunoblots of PVDF membranes is at least as effective as that previously described for nitrocellulose, but the greater ease of use of the new mixture makes PVDF the membrane of choice for transmission densitometry. Using a blot onto PVDF of monoclonal IgG probed with anti-mouse antibody, laser transmission densitometry revealed that the stained peak area was related to loading in a linear fashion over a 60-fold range on a single blot.

Animals↗
PubMed1995

Morpho-densitometry of bone using a trigonometric function.

When long bone is considered to be a tube-like structure filled up with a homogenous material, single-directional densitometry of it separately shows cortical and medullary bone mass using a trigonometric function at any given section. Both bone masses can be differentiated from each other using the values of peak bone density and central bone density. This densitometry is based on the two-dimensional structure of long bone. This principle can be universally applied to skeletal disorders including osteoporosis, metabolic bone disorders, and bone tumors in which the mineral content is altered. Dynamic changes in calcium metabolism can be analyzed serially without any invasion at low cost.

Absorptiometry, Photon↗
PubMed2006

Official positions of the International Society for Clinical Densitometry and Executive Summary of the 2005 Position Development Conference.

The International Society for Clinical Densitometry (ISCD) convenes a Position Development Conference (PDC) every two years for the purpose of making recommendations on clinically relevant issues in bone densitometry. Topics for consideration are developed by the ISCD Scientific Advisory Committee and the PDC Steering Committee. Clinically relevant questions related to each topic area are assigned to subcommittees for a comprehensive medical literature review and presentation of a report to an international panel of experts. The expert panel includes representatives of the American Society for Bone and Mineral Research (ASBMR) and the International Osteoporosis Foundation (IOF). The recommendations of the PDC expert panel are evaluated by the ISCD Board of Directors, and those that are approved become Official Positions of the ISCD. The Official Positions have subsequently been endorsed by the ASBMR and IOF. The most recent PDC was held July 15-17, 2005, in Vancouver, BC, Canada. Topics considered included technical standardization, vertebral fracture assessment, and application of the 1994 World Health Organization (WHO) criteria to various skeletal sites and to populations other than postmenopausal white women. This report describes the methodology of the 2005 PDC and presents a summary of all ISCD Official Positions.

Absorptiometry, Photon↗
PubMed2005

Contrast sonography, video densitometry and intervillous blood flow: a pilot project.

PURPOSE: To examine the feasibility of constructing time-intensity (TI) curves from the intervillous space with an intravascular ultrasound contrast agent and computer assisted video densitometry. STUDY DESIGN: We sedated nine pregnant baboons, optimized the grey scale and color Doppler images of their placentas, and then fixed the transducers in place. For each injection of contrast, we recorded images on videotape without changing the ultrasound image processing functions. Video images were captured using a Macintosh personal computer equipped with a video-capture board using image analysis software (Image 1.4, W Rasband, NIH). For each injection, we sampled digitized images of a fixed region of interest at regular intervals. After computing the mean video density of each image, we used the sampling frequency to construct TI curves depicting any change over time as the contrast agents washed into and out of the intervillous space. RESULTS: Three of four agents tested produced changes in the video density of the placenta. TI curves were established using both grey scale and color Doppler signal augmentation. As expected, intra-arterial agents produced rapid accumulation and decay. Intravenous agents produced more protracted effects secondary to bolus dilution and transit through the right heart and pulmonary vascular bed. CONCLUSION: TI curves may be generated from the intervillous space with the use of a transpulmonary ultrasound contrast agent and video densitometry. If validated by further study, this may allow investigators to apply ultrasound and indicator-dilution theory to intervillous blood flow.

Animals↗
PubMed1992

Foveal densitometry in adult-onset diffuse drusen.

We compared the results of foveal densitometry with results of other retinal function tests in five asymptomatic subjects with adult-onset diffuse drusen. All results of routine retinal function tests, including visual acuity, Rayleigh equation color matches, multiple static perimetry, electroretinography, and electro-oculography, were normal. All five subjects had decreased foveal cone photopigment density with densitometry, indicating an early dysfunction at the level of the foveal cone photoreceptors. Several functional defects may be responsible for the densitometric results in adult-onset diffuse drusen, including retinal pigment epithelium dysfunction, foveal cone photoreceptor misalignment, and a reduction of the in situ foveal cone photopigment.

Adult↗
PubMed1978

A rapid, sensitive method for accurate analysis of individual bile acids in biological fluids by high performance thin-layer chromatography and densitometry.

1. A rapid new micromethod for quantitative analysis of individual bile acids in duodenal juice by high performance thin-layer chromatography (HPTLC) and densitometry is described and evaluated by comparison with standard TLC and spectrophotometry. 2. Advantages of HPTLC over TLC include more rapid separation, better resolution and more sensitive detection (5 - 10 fold), without the need for prior extraction. Densitometry provides simple, direct and rapid quantitation. 3. The method is accurate and reliable over a range of bile acid concentrations. In the 0.5 mM range, recovery was greater than 89%, and coefficients of variation for within-day analysis were 2 - 12% and for between-day analysis were 6 - 18% for the individual bile acids. Twenty analyses can be performed by one worker in a single day. 4. We conclude that the method offers several advantages over most currently described techniques, is suitable for routine use and is deserving of wider application.

Bile Acids and Salts↗
PubMed1990

Hadamard transform photothermal deflection densitometry of electrophoretically blotted proteins.

Hadamard transform spatial multiplexing techniques are applied to laser densitometry in order to prevent the photo-induced degradation of sensitive materials. Photochemical and thermal degradations can often occur in point focused scanning laser densitometry. In spatial multiplexing, the excitation source is defocused and efficiently distributed throughout the sample, reducing local power density. In this paper, we describe the application of Hadamard transform spatial multiplexing to transverse photothermal deflection spectroscopy (PDS). Proteins western blotted on nitrocellulose membrane are line imaged using the Hadamard transform PDS densitometer. For comparison, the blots are imaged with a high-dynamic-range video densitometer.

Alkaline Phosphatase↗
PubMed1999

Determination of Ole e 1 by enzyme immunoassay and scanning densitometry. Validation by skin-prick testing.

Ole e 1 is an important allergen in Olea europaea pollen extracts. This study describes the development of two new methods that can be used to estimate the Ole e 1 content in olive tree pollen extracts. They are based on (1) an enzyme immunoassay that uses rabbit polyclonal, monospecific antibodies and purified Ole e 1, and (2) scanning densitometry of SDS-PAGE gels. Twelve extracts were evaluated by in vivo and in vitro methods. The in vivo biological potency was estimated by prick skin testing 17 allergic individuals; the in vitro allergenic potency by direct IgE and IgE inhibition assays. The enzyme immunoassay showed an operative range of 0.03-100 microg/ml and demonstrated to be specific for Ole e 1. The Ole e 1 content ranged from 1% to 5% of the total protein in the 12 extracts. The amount of Ole e 1, assessed by gel scanning densitometry significantly correlated with the Ole e 1 content obtained by the immunoassay (r = 0.92; p < 0.001). The Ole e 1 content showed a significant correlation with the total allergenic potency of the extracts, evaluated by direct IgE, specific IgE inhibition and skin-prick testing. These two methods can be used to determine the Ole e 1 content in olive pollen extracts. The content of Ole e 1 can vary from 1% to 5% of the total protein in the extracts.

Allergens↗
PubMed2001

Quantitative determination of alpha-tocopherol in Arbutus unedo by TLC-densitometry and colorimetry.

A quantitative determination of alpha-tocopherol in Arbutus unedo leaves was established by TLC-densitometry and colorimetry. Data obtained by TLC-densitometry were compared with those obtained by colorimetry. Also, the alpha-tocopherol content in leaves collected at different times of the year was studied comparatively. The highest amount of alpha-tocopherol was found in the March collection.

Chromatography, Thin Layer↗
PubMed1985

Determination of nitrazepam and its main metabolites in urine by thin-layer chromatography and direct densitometry.

A method for the direct quantitative densitometry of nitrazepam and its main metabolites (7-aminonitrazepam, 7-acetamidonitrazepam and 2-amino-5-nitrobenzophenone) in urine was developed. The unchanged drug and its metabolites were extracted with benzene-dichloromethane (4:1), subjected to thin-layer chromatography, and determined by direct ultraviolet densitometry. Recovery experiments showed that the method was quantitative. The limit of detection was 5 ng/ml for 2-amino-5-nitrobenzophenone and 10 ng/ml for other compounds. The method was applied to the determination of nitrazepam and its metabolites excreted in human urine after administration of 10 mg of the drug.

Adult↗
PubMed2003

Quantitative determination of diazepam, nitrazepam and flunitrazepam in tablets using thin-layer chromatography-densitometry technique.

A simple and reliable assay for diazepam, nitrazepam and flunitrazepam in tablets by high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC)-densitometry is described. A quantity of a ground tablet mass, equal to the average weight of one tablet was sonicated in MeOH, mixed with appropriate internal standard, filtered and either injected directly into the liquid chromatograph, or after evaporation and reconstitution of an aliquot of the extract, was spotted on a silica gel thin-layer plate. A variable UV detector, operated at 254 nm was employed in both procedures. A C18, reversed phase 7 microm column was used for HPLC analysis; the mobile phase was a 1:1 (v/v) mixture of MeOH (40 degrees C) and 0.01 M phosphate buffer (pH 7, 80 degrees C). The TLC plate was developed in an unsaturated chromatographic chamber containing 100 ml chloroform-acetone (9:1); at room temperature, the mobile phase was allowed to travel 15 cm. The percentage of the active ingredient content of each tablet obtained by both procedures, was in the range of the stated amount except for one brand of diazepam tablets which contained approximately 23% less active ingredient than the minimum prescribed amount. The TLC densitometry, although yields slightly higher values than the HPLC method, is preferred due to its simplicity, ease and low cost.

Chromatography, Thin Layer↗
PubMed2003

Assay and purity control of tetracycline, chlortetracycline and oxytetracycline in animal feeds and premixes by TLC densitometry with fluorescence detection.

Methods using TLC densitometry with fluorescence detection are described for the assay and purity control of tetracycline (TC), chlortetracycline (CTC), and oxytetracycline (OTC) in animal feeds and premixes. With a silica gel layer previously sprayed with 10% (m/v) sodium EDTA solution adjusted to pH 8.0 or 9.0, all the major impurities were separated from the main components and from each other. The mobile phase consisted of dichloromethane, methanol, and water. After development, the plate was dipped in a 30% (v/v) solution of liquid paraffin in hexane. Quantitation was realized by fluorescence densitometry at 400 nm. The limit of quantitation (LOQ) for tetracycline impurities is 0.8 microg/g, corresponding to 0.2% of the label claimed tetracycline (400 microg/g). The LOQ for impurities of tetracycline and chlortetracycline in premixes is 0.2% of the label-claimed TC (40 mg/g) and CTC (200 or 400 mg/g). The LOQ for impurities of oxytetracycline in a premix is 0.1% of the label claimed OTC (100 mg/g).

Animal Feed↗
PubMed1999

Assessment by pulse dye-densitometry indocyanine green (ICG) clearance test of hepatic function of patients before cardiac surgery: its value as a predictor of serious postoperative liver dysfunction.

OBJECTIVE: Patients with preoperative liver dysfunction occasionally have a poor prognosis after cardiac surgery because the liver condition is aggravated. The pulse dye-densitometry indocyanine green (ICG) clearance test was used as a preoperative evaluation technique. DESIGN: Prospective, clinical evaluation. SETTING: Surgical intensive care unit of a national cardiovascular center. SUBJECTS: Twenty-seven patients with preoperative liver dysfunction were studied. They were divided into four groups depending on the cause of their liver dysfunction. INTERVENTIONS: With the patient's informed consent, a bolus of ICG, 20 mg, was injected, and the disappearance of ICG was measured noninvasively by pulse dye-densitometry. MEASUREMENTS AND MAIN RESULTS: The ICG retention rate at 15 minutes (ICG-R15) was calculated for the regression time. The patients were assessed in terms of ICG-R15 and the cause of liver dysfunction. The ICG-R15 values obtained for all 27 patients were 30% +/- 16% (mean +/- standard deviation). The 21 survivors had ICG-R15 values of 24% +/- 12%, whereas the 6 patients who died after surgery had significantly greater ICG-R15 values of 50% +/- 13% (p < 0.05). The mean values of ICG-R15 in patients with congestive liver, viral hepatitis accompanied by congestive liver, viral hepatitis, and cirrhosis were 34%, 23%, 13%, and 42%, respectively. The 6 of 27 patients who died after surgery had ICG-R15 values greater than 40%. Five of the seven patients with cirrhosis died. CONCLUSION: These results suggest that (1) compared with Child-Pugh classification, the value of ICG-R15 provides a more accurate surgical indication; and (2) liver dysfunction from cirrhosis causes postoperative deterioration of liver function, especially when the ICG-R15 value exceeds 40%.

Adult↗
PubMed1997

Physician characteristics associated with the use of bone densitometry.

To determine physician characteristics associated with the use of bone densitometry (BD), we conducted a cross-sectional survey of primary care practitioners in an urban community hospital. Participants were internists, geriatricians, and family practitioners. Seventy-two percent of the physicians never used BD. There was no association between physician or practice characteristics and BD use. Bone densitometry users were more likely than nonusers to treat their patients with osteoporosis or at risk of developing it. Self-reported barriers to use included cost, unfamiliarity with guidelines, uncertainty with clinical applicability, minimal impact on treatment decisions, and availability. In conclusion, although it has been shown that osteoporotic women who are aware of their BD results are more likely to accept treatment, further attention should be paid to primary care practitioners' attitudes, knowledge, and behavior regarding the use of BD in the management of osteoporosis.

Adult↗
PubMed1975

[New basic considerations and theories for improving angio-cine-densitometry. IV. The effect of discontinuous, pulsatile flow on angio-cine-densitometric measurements (author's transl)].

Various expressions of the speed of flow of blood in arteries are discussed, such as instantaneous speed, integral speed, pulse wave speed (phase speed) and velocity of a moving front. The flow profile of the abdominal aorta was obtained by cine-densitometry, bearing in mind the above considerations, and the densitometric curves have been analysed. Differences of the flow velocities in different persons have been interpreted as a result of these theoretical considerations. The effects of the point of measurement, the distance over which the measurement was carried out and the pulse wave length on velocity were examined. In order to obtain a median blood stream velocity by angio-cine-densitometry, repeated injections of small volumes of contrast medium (random sampling method) are recommended.

Blood Flow Velocity↗
PubMed1996

The validity of predicted body composition in Chinese adults from anthropometry and bioelectrical impedance in comparison with densitometry.

Body composition was measured by densitometry in a group of eighty-one Chinese males and 124 healthy Chinese females, aged 18-67 years. Biceps, triceps, subscapular and suprailiac skinfolds were measured as well as total body bioelectrical impedance at 50 kHz. Mean heights were 1.71 (SD 0.05) and 1.61 (SD 0.06) m, body weights 66.1 (SD 9.1) and 57.2 (SD 9.4) kg and BMI 22.7 (SD 3.0) and 22.0 (SD 3.3) kg/m2 in males and females respectively. Body fat values from body density were 20.1 (SD 6.2) and 29.7 (SD 7.5)% in males and females respectively. Mean predicted body-fat values from skinfolds, bioelectrical impedance and BMI, using prediction formulas developed in Western populations, did not differ or differed only slightly from body-fat values estimated from body density. The SD of the difference for each method was 5% body fat or 3.3 kg fat-free mass (CV 6%), which is approximately equal to the accuracy level of each predictive method. Compared with densitometry the predictive methods overestimated body fat at the lower levels of body fatness, whereas at the higher levels of body fat the predictive methods tended to underestimate body fatness. It is concluded that prediction formulas for estimating body fat from skinfolds, impedance or BMI developed in Western populations are applicable and valid in the adult Chinese population. However, in very lean subjects the predictive methods overestimate body fat compared with values obtained from body density.

Adipose Tissue↗