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Journal of Chromatographic Science Nov 2022From evolution, thin-layer chromatography (TLC) attracts attention as a versatile technique for efficient separation and identification of many drug substances and...
Versatile TLC-Densitometric Methods for the Synchronous Estimation of Cinnarizine and Acefylline Heptaminol in The Presence of Potential Impurity and Their Reported Degradation Products.
From evolution, thin-layer chromatography (TLC) attracts attention as a versatile technique for efficient separation and identification of many drug substances and chemicals. Owing to its simplicity and other outstanding advantages, TLC is extensively used by chromatographers in quantification and purity profiling objectives. In the present study two TLC-Densitometric methods are established and validated for the synchronous estimation of Cinnarizine (Cinn) and Acefyline Heptaminol (Acef) in the presence of Cinn/Acef reported degradation products and Thoephylline (Theo) as Acef potential impurity. The proposed methods are based on densitometric measurements of the spots of Cinn and Acef after separation from their degradation products. Separation is attained on silica gel sheet with dichloromethane: methanol: formic acid as a developing system in ratio: (15, 1, 0.5, by volume) and (15, 0.75, 0.4, by volume) for Cinn (method 1) and Acef (method 2) degradation, consecutively. Quantification is done at 254 nm over concentration ranges of 0.2-1.8 and 2-18 μg/spot for Cinn and Acef; respectively, with mean percentage recoveries of 99.18 ± 0.60/99.84 ± 0.53 and 99.19 ± 0.93/99.66 ± 0.58 for method 1 and method 2; consecutively. The two methods are fully validated and proven to be selective, robust and retained their accuracy in up to 50% of Cinn/Acef reported degradation products and Theo. Moreover, the two methods are applied to a coformulated drug product comprising Cinn and Acef showing satisfactory results. Comparison of the obtained results by the proposed methods with that of the reference ones statistically shows no significant differences.
Topics: Chromatography, Thin Layer; Cinnarizine; Densitometry; Heptaminol; Reproducibility of Results
PubMed: 34875682
DOI: 10.1093/chromsci/bmab129 -
IEEE Transactions on Ultrasonics,... 2008The article presents a retrospective view on the assessment of long bones condition using topographical patterns of the acoustic properties. The application of... (Review)
Review
The article presents a retrospective view on the assessment of long bones condition using topographical patterns of the acoustic properties. The application of ultrasonic point-contact transducers with exponential waveguides on a short acoustic base for detailed measurements in human long bones by the surface transmission was initiated during the 1980s in Latvia. The guided wave velocity was mapped on the surface of the long bones and the topographical patterns reflected the biomechanical peculiarities. Axial velocity profiles obtained in vivo by measurements along the medial surface of tibia varied due to aging, hypokinesia, and physical training. The method has been advanced at Artann Laboratories (West Trenton, NJ) by the introduction of multifrequency data acquisition and axial scanning. The model studies carried out on synthetic phantoms and in bone specimens confirmed the potential to evaluate separately changes of the bone material properties and of the cortical thickness by multifrequency acoustic measurements at the 0.1 to 1 MHz band. The bone ultrasonic scanner (BUSS) is an axial mode ultrasonometer developed to depict the acoustic profile of bone that will detect the onset of bone atrophy as a spatial process. Clinical trials demonstrated a high sensitivity of BUSS to osteoporosis and the capability to assess early stage of osteopenia.
Topics: Acoustics; Algorithms; Biomechanical Phenomena; Bone Diseases; Bone and Bones; Clinical Trials as Topic; Computer Simulation; Densitometry; Humans; Image Interpretation, Computer-Assisted; Models, Biological; Scattering, Radiation; Ultrasonography
PubMed: 18599416
DOI: 10.1109/TUFFC.2008.791 -
Sao Paulo Medical Journal = Revista... Jan 2010Identification of women at risk of bone fracture is becoming less dependent on evaluating bone mineral density through placing greater value on clinical risk factors....
CONTEXT AND OBJECTIVE
Identification of women at risk of bone fracture is becoming less dependent on evaluating bone mineral density through placing greater value on clinical risk factors. The aim of this study was to evaluate the sensitivity of the Osteorisk clinical tool for identifying Brazilian postmenopausal women with osteoporosis, compared with bone densitometry.
DESIGN AND SETTING
Cross-sectional observational study at Faculdade de Medicina do ABC.
METHOD
Information on 812 postmenopausal osteoporotic women was retrospectively evaluated from medical records. The women were divided into the age groups 50-59, 60-69, 70-79 and over 80 years. The results from the Osteorisk clinical tool, which uses only age and weight, were compared with bone densitometry T-scores.
RESULTS
There were significant correlations between the results from the Osteorisk clinical tool and from bone densitometry, in relation to the lumbar spine (P = 0.027) and hip (P < 0.001), thus showing a non-arbitrary relationship. The overall sensitivity of Osteorisk for identifying women with "high risk of osteoporosis" was 86.5%, and it was higher for hip osteoporosis alone (97.2%) than for lumbar spine osteoporosis (85.8%). The sensitivity was better among older women.
CONCLUSION
Osteorisk seems to present good sensitivity for identifying postmenopausal women at risk of osteoporosis. It should be used when bone densitometry is not easily available or as a means of selecting individuals for referral for bone densitometry.
Topics: Aged; Aged, 80 and over; Body Mass Index; Body Weight; Bone Density; Brazil; Densitometry; Epidemiologic Methods; Female; Humans; Lumbar Vertebrae; Middle Aged; Osteoporosis, Postmenopausal; Radiography; Retrospective Studies
PubMed: 20512277
DOI: 10.1590/s1516-31802010000100006 -
PloS One 2022The purpose of this study is to evaluate the quantitative diagnostic performance of computed tomography (CT) densitometry in pediatric patients with bronchiolitis...
The purpose of this study is to evaluate the quantitative diagnostic performance of computed tomography (CT) densitometry in pediatric patients with bronchiolitis obliterans (BO). We measured the mean lung density (MLD) and represented the difference of MLD in inspiratory and expiratory phases (MLDD), the ratio of the MLD (E/I MLD), and the relative volume percentage of lung density at 50-Hounsfield unit (HU) interval threshold (E600 to E950). We calculated the sensitivity, specificity, and diagnostic accuracy of the lung density indices for the diagnosis of BO. A total of 81 patients, including 51 patients with BO and 30 controls, were included in this study. In the BO patients, expiratory (EXP) MLD and MLDD were significantly lower, and E/I MLD and expiratory low attenuation areas below the threshold of -850 HU to -950 HU (E850, E900, and E950) were statistically significantly higher than controls. Multivariate logistic regression analysis showed that MLDD (odds ratio [OR] = 0.98, p < .001), E/I MLD (OR = 1.39, p < .001), and E850 to E950 were significant densitometry parameters for BO diagnosis. In a receiver-operating characteristic analysis, E900 (cutoff, 1.4%; AUC = 0.920), E/I MLD (cutoff, 0.87; AUC = 0.887), and MLDD (cutoff, 109 HU; AUC = 0.867) showed high accuracy for the diagnosis of BO. In conclusion, the lung CT densitometry can serve as a quantitative marker providing additional indications of expiratory airflow limitation in pediatric patients with BO.
Topics: Bronchiolitis Obliterans; Child; Densitometry; Humans; Lung; Lung Diseases; Respiratory Function Tests; Tomography, X-Ray Computed
PubMed: 35797398
DOI: 10.1371/journal.pone.0271135 -
Journal of Applied Physiology... Nov 2001Differences in the mineral fraction of the fat-free mass (M(FFM)) and in the density of the FFM (D(FFM)) are often inferred from measures of bone mineral content (BMC)... (Clinical Trial)
Clinical Trial
Differences in the mineral fraction of the fat-free mass (M(FFM)) and in the density of the FFM (D(FFM)) are often inferred from measures of bone mineral content (BMC) or bone mineral density (BMD). We studied the relation of BMC and BMD to the M(FFM) and D(FFM) in a heterogeneous sample of 216 young men (n = 115) and women (n = 101), which included whites (n = 155) and blacks (n = 61) and collegiate athletes ( n = 132) and nonathletes (n = 84). Whole body BMC and BMD were determined by dual-energy X-ray absorptiometry (DXA; Hologic QDR-1000W, enhanced whole body analysis software, version 5.71). FFM was estimated using a four-component model from measures of body density by hydrostatic weighing, body water by deuterium dilution, and bone mineral by DXA. There was no significant relation of BMD to M(FFM) (r = 0.01) or D(FFM) (r = -0.06) or of BMC to M(FFM) (r = -0.11) and a significant, weak negative relation of BMC to D(FFM) (r = -0.14, P = 0.04) in all subjects. Significant low to moderate relationships of BMD or BMC to M(FFM) or D(FFM) were found within some gender-race-athletic status subgroups or when the effects of gender, race, and athletic status were held constant using multiple regression, but BMD and BMC explained only 10-17% of the variance in M(FFM) and 0-2% of the variance in D(FFM) in addition to that explained by the demographic variables. We conclude that there is not a significant positive relation of BMD and BMC to M(FFM) or D(FFM) in young adults and that BMC and BMD should not be used to infer differences in M(FFM) or D(FFM).
Topics: Absorptiometry, Photon; Adult; Body Composition; Body Water; Bone Density; Bone and Bones; Densitometry; Female; Humans; Male; Minerals; Physical Fitness; Racial Groups; Sex Characteristics; Sports
PubMed: 11641358
DOI: 10.1152/jappl.2001.91.5.2166 -
Journal of Neuroscience Methods Nov 1983A low cost spot densitometer system is described. This system is useful for quantitative autoradiography of local cerebral glucose utilization, blood flow, receptor...
A low cost spot densitometer system is described. This system is useful for quantitative autoradiography of local cerebral glucose utilization, blood flow, receptor binding and other applications requiring densitometry on films. The densitometer can be used alone or interfaced to a microcomputer. The densitometer consists of a photographic enlarger, a digital multimeter, and the densitometer electronics. We have described how to construct, test and use the densitometer and how to interface the densitometer to a microcomputer. The advantages of this system are: (1) the ability to enlarge the image for accurate measurements from 'small' areas; (2) a completely unobscured image during measurement; (3) low cost and (4) ease of use.
Topics: Animals; Autoradiography; Brain; Cerebrovascular Circulation; Densitometry; Microcomputers; Rats; Receptors, Neurotransmitter
PubMed: 6319831
DOI: 10.1016/0165-0270(83)90087-0 -
Journal of Bone and Mineral Research :... Jan 2017The increasing use of dual-energy X-ray absorptiometry (DXA) in children has led to the need for robust reference data for interpretation of scans in daily clinical...
The increasing use of dual-energy X-ray absorptiometry (DXA) in children has led to the need for robust reference data for interpretation of scans in daily clinical practice. Such data need to be representative of the population being studied and be "future-proofed" to software and hardware upgrades. The aim was to combine all available pediatric DXA reference data from seven UK centers to create reference curves adjusted for age, sex, ethnicity, and body size to enable clinical application, using in vivo cross-calibration and making data back and forward compatible. Seven UK sites collected data on GE Lunar or Hologic Scanners between 1996 and 2012. Males and females aged 4 to 20 years were recruited (n = 3598). The split by ethnic group was white 2887; South Asian 385; black Afro-Caribbean 286; and mixed heritage 40. Scans of the total body and lumbar spine (L to L ) were obtained. The European Spine Phantom was used to cross-calibrate the 7 centers and 11 scanners. Reference curves were produced for L to L bone mineral apparent density (BMAD) and total body less head (TBLH) and L to L areal bone mineral density (aBMD) for GE Lunar Prodigy and iDXA (sex- and ethnic-specific) and for Hologic (sex-specific). Regression equations for TBLH BMC were produced using stepwise linear regression. Scans of 100 children were randomly selected to test backward and forward compatibility of software versions, up to version 15.0 for GE Lunar and Apex 4.1 for Hologic. For the first time, sex- and ethnic-specific reference curves for lumbar spine BMAD, aBMD, and TBLH aBMD are provided for both GE Lunar and Hologic scanners. These curves will facilitate interpretation of DXA data in children using methods recommended in ISCD guidelines. The databases have been created to allow future updates and analysis when more definitive evidence for the best method of fracture prediction in children is agreed. © 2016 American Society for Bone and Mineral Research.
Topics: Absorptiometry, Photon; Adolescent; Anthropometry; Body Size; Bone Density; Bone and Bones; Child; Child, Preschool; Densitometry; Female; Humans; Lumbar Vertebrae; Male; Phantoms, Imaging; Reference Values; Young Adult
PubMed: 27490028
DOI: 10.1002/jbmr.2935 -
PloS One 2012Classical violins produced by makers such as Antonio Stradivari and Guarneri del Gesu have long been considered the epitome of the luthier's art and the expressive tool... (Comparative Study)
Comparative Study
Classical violins produced by makers such as Antonio Stradivari and Guarneri del Gesu have long been considered the epitome of the luthier's art and the expressive tool of choice for the most celebrated violinists. It has been speculated these makers had access to wood that was unique in some way and that this was responsible for their acclaimed tonal characteristics. In an attempt to discern whether the above conjecture is true, we analyzed 17 modern and classical Dutch, German, Austrian and French violins by wood densitometry using computed tomography and correlated these results with our previous study of modern and Cremonese violins; in all studying 30 instruments of the violin family. In order to make this comparison possible we developed methods to cross calibrate results from different CT manufacturers using calibration wood pieces. We found no significant differences in median densities between modern and classical violins, or between classical violins from different origins. These results suggest that it is unlikely classical Cremonese makers had access to wood with significantly different wood density characteristics than that available to contemporaneous or modern makers.
Topics: Densitometry; Elastic Modulus; Europe; History, 17th Century; History, 18th Century; History, 21st Century; Image Processing, Computer-Assisted; Specific Gravity; Tomography, X-Ray Computed; Wood
PubMed: 23071602
DOI: 10.1371/journal.pone.0046629 -
BMC Bioinformatics Feb 2020Protein microarrays are a versatile and widely used tool for analyzing complex protein mixtures. Membrane arrays utilize antibodies which are captured on a membrane to...
BACKGROUND
Protein microarrays are a versatile and widely used tool for analyzing complex protein mixtures. Membrane arrays utilize antibodies which are captured on a membrane to specifically immobilize several proteins of interest at once. Using detection antibodies, the bound protein-antibody-complex is converted into visual signals, which can be quantified using densitometry. The reliability of such densitometric assessments depends on a variety of factors, not only sample preparation and the choice of acquisition device but also the selected analysis software and the algorithms used for readout and processing data. Currently available software packages use a single image of a membrane at an optimal exposure time selected for that specific experimental framework. This selection is based on a user's best guess and is subject to inter-user variability or the acquisition device algorithm. With modern image acquisition systems proving the capacity to collect signal development over time, this information can be used to improve densitometric measurements. Here we introduce proMAD, a toolkit for protein microarray analysis providing a novel systemic approach for the quantification of membrane arrays based on the kinetics of the analytical reaction.
RESULTS
Briefly, our toolkit ensures an exact membrane alignment, utilizing basic computer vision techniques. It also provides a stable method to estimate the background light level. Finally, we model the light production over time, utilizing the knowledge about the reaction kinetics of the underlying horseradish peroxidase-based signal detection method.
CONCLUSION
proMAD incorporates the reaction kinetics of the enzyme to model the signal development over time for each membrane creating an individual, self-referencing concept. Variations of membranes within a given experimental set up can be accounted for, allowing for a better comparison of such. While the open-source library can be implemented in existing workflows and used for highly user-tailored analytic setups, the web application, on the other hand, provides easy platform-independent access to the core algorithm to a wide range of researchers. proMAD's inherent flexibility has the potential to cover a wide range of use-cases and enables the automation of data analytic tasks.
Topics: Algorithms; Densitometry; Immunoenzyme Techniques; Protein Array Analysis; Software; Workflow
PubMed: 32093608
DOI: 10.1186/s12859-020-3402-4 -
Electrophoresis Dec 2017Modified colloidal Coomassie Brilliant Blue (cCBB) staining utilising a novel destain protocol and near-infrared fluorescence detection (nIRFD) rivals the in-gel protein...
Modified colloidal Coomassie Brilliant Blue (cCBB) staining utilising a novel destain protocol and near-infrared fluorescence detection (nIRFD) rivals the in-gel protein detection sensitivity (DS) of SYPRO Ruby. However, established DS estimates are likely inaccurate in terms of 2DE-resolved proteoform 'spots' since DS is routinely measured from comparatively diffuse protein 'bands' following wide-well 1DE. Here, cCBB DS for 2DE-based proteomics was more accurately determined using narrow-well 1DE. As precise estimates of protein standard monomer concentrations are essential for accurate quantitation, coupling UV absorbance with gel-based purity assessments is described. Further, as cCBB is compatible with both nIRFD and densitometry, the impacts of imaging method (and image resolution) on DS were assessed. Narrow-well 1DE enabled more accurate quantitation of cCBB DS for 2DE, achieving (sub)femtomole DS with either nIRFD or densitometry. While densitometry offers comparative simplicity and affordability, nIRFD has the unique potential for enhanced DS with Deep Imaging. Higher-resolution nIRFD also improved analysis of a 2DE-resolved proteome, surpassing the DS of standard nIRFD and densitometry, with nIRFD Deep Imaging further maximising proteome coverage. cCBB DS for intact proteins rivals that of mass spectrometry (MS) for peptides in complex mixtures, reaffirming that 2DE-MS currently provides the most routine, broadly applicable, robust, and information-rich Top-down approach to Discovery Proteomics.
Topics: Densitometry; Electrophoresis, Gel, Two-Dimensional; Limit of Detection; Proteome; Proteomics; Rosaniline Dyes
PubMed: 28872692
DOI: 10.1002/elps.201700190