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Molecules (Basel, Switzerland) Aug 2020Histamine poisoning is a significant public health problem. Therefore, the monitoring of histamine content in fish and fishery products is considered to be a crucial...
Histamine poisoning is a significant public health problem. Therefore, the monitoring of histamine content in fish and fishery products is considered to be a crucial measure in the seafood industry. In the present study, a simple and rapid densitometric thin-layer chromatographic (TLC) method for histamine determination in fish samples was developed and validated. The samples were homogenized with 10% trichloroacetic acid and histamine was efficiently extracted. Then, an appropriate derivatization procedure was adopted with dansyl chloride. Once the derivatization was carried out, the samples were applied to silica gel TLC plates and developed by ascending chromatography with chloroform-triethylamine (6:4, /) as the mobile phase. The intensity of the histamine-dansyl derivative spots was measured by densitometry at 365 nm, and the quantitation was performed by BIO-1D image processing software. The validation of this method revealed good linearity and specificity over a concentration range from 6.25 to 100 mg/kg. Adequate precision was shown by relative standard deviations (RSD) smaller than 4.82%, accuracy ranged from -6.88% to 5.28%, and satisfactory recoveries ranging from 93% to 105% were obtained. The Limit of Detection and the Limit of Quantification were calculated at 4.4 mg/kg and 10.5 mg/kg, respectively. In addition, the effectiveness of the proposed method was assessed by the analysis of various samples, and the obtained results were confirmed with those achieved by the HPLC-UV method. Moreover, the developed method was found to be simple, cheap, and suitable for application to analyze several samples simultaneously.
Topics: Animals; Chromatography, Thin Layer; Densitometry; Fisheries; Fishes; Food Analysis; Food Contamination; Histamine; Limit of Detection; Time Factors
PubMed: 32784469
DOI: 10.3390/molecules25163611 -
Nature Clinical Practice. Rheumatology Dec 2008Bone mineral density (BMD) testing is used to diagnose osteoporosis, assess fracture risk and monitor changes in BMD over time. A variety of devices and technologies are... (Review)
Review
Bone mineral density (BMD) testing is used to diagnose osteoporosis, assess fracture risk and monitor changes in BMD over time. A variety of devices and technologies are used to measure BMD or other surrogate markers of bone strength. Measurements obtained with these devices are often reported according to different proprietary standards, and the comparability of values obtained with different instruments is often poor. In addition, there is a high degree of variability in the skills of the technologists performing the tests and the clinicians interpreting the results. Heterogeneity in the guidelines for using BMD measurements together with poor-quality BMD testing and reporting can result in inappropriate clinical decisions, causing unnecessary worry and expense for the patient and possible harm due to unnecessary treatment or treatment being withheld. This Review describes and discusses the mistakes commonly made in BMD testing, and emphasizes the importance of maintaining high-quality standards in order to optimize patient management.
Topics: Absorptiometry, Photon; Bone Density; Data Interpretation, Statistical; Diagnostic Errors; Humans
PubMed: 18936788
DOI: 10.1038/ncprheum0928 -
Journal of Clinical Densitometry : the... 2021Body composition is associated with many noncommunicable diseases. The accuracy of many simple techniques used for the assessment of body composition is influenced by...
Body composition is associated with many noncommunicable diseases. The accuracy of many simple techniques used for the assessment of body composition is influenced by the fact that they do not take into account tissue hydration and this can be particularly problematic in paediatric populations. The aims of this study were: (1) to assess the agreement of two dual energy X-ray absorptiometry (DXA) systems for determining total and regional (arms, legs, trunk) fat, lean, and bone mass and (2) to compare lean soft tissue (LST) hydration correction methods in children. One hundred and twenty four healthy children aged between 6 and 16 years old underwent DXA scans using 2 GE healthcare Lunar systems (iDXA and Prodigy). Tissue hydration was either calculated by dividing total body water (TBW), by 4-component model derived fat free mass (HFFM) or by using the age and sex specific coefficients of Lohman, 1986 (HFFM) and used to correct LST. Regression analysis was performed to develop cross-calibration equations between DXA systems and a paired samples t-test was conducted to assess the difference between LST hydration correction methods. iDXA resulted in significantly lower estimates of total and regional fat and lean mass, compared to Prodigy. HFFM showed a much larger age/sex related variability than HFFM. A 2.0 % difference in LST was observed in the boys (34.5 kg vs 33.8 kg respectively, p < 0.05) and a 2.5% difference in the girls (28.2 kg vs 27.5 kg respectively, p < 0.05) when corrected using either HFFM or HFFM Care needs to be exercised when combining data from iDXA and Prodigy, as total and regional estimates of body composition can differ significantly. Furthermore, tissue hydration should be taken into account when assessing body composition as it can vary considerably within a healthy paediatric population even within specific age and/or sex groups.
Topics: Absorptiometry, Photon; Adolescent; Body Composition; Bone Density; Child; Female; Humans; Leg; Male; Torso
PubMed: 33454177
DOI: 10.1016/j.jocd.2020.12.004 -
British Medical Journal Jun 1962
Topics: Densitometry; Humans; Lumbar Vertebrae; Osteoporosis; Radiography; Spine
PubMed: 14480294
DOI: 10.1136/bmj.1.5295.1793 -
BioMed Research International 2019Densitometry data generated for Western blots are commonly used to compare protein abundance between samples. In the last decade, it has become apparent that assumptions...
Densitometry data generated for Western blots are commonly used to compare protein abundance between samples. In the last decade, it has become apparent that assumptions underpinning these comparisons are often violated in studies reporting Western blot data in the literature. These violations can lead to erroneous interpretations of data and may contribute to poor reproducibility of research. We assessed the reliability of Western blot data obtained to study human myometrial tissue proteins. We ran dilution series of protein lysates to explore the linearity of densitometry data. Proteins analysed included SMA, HSP27, ERK1/2, and GAPDH. While ideal densitometry data are directly proportional to protein abundance, our data confirm that densitometry data often deviate from this ideal, in which case they can fit nonproportional linear or hyperbolic mathematical models and can reach saturation. Nonlinear densitometry data were observed when Western blots were detected using infrared fluorescence or chemiluminescence, and under different SDS-PAGE conditions. We confirm that ghosting artefacts associated with overabundance of proteins of interest in Western blots can skew findings. We also confirm that when data to be normalised are not directly proportional to protein abundance, it is a mistake to use the normalisation technique of dividing densitometry data from the protein-of-interest with densitometry data from loading control protein(s), as this can cause the normalised data to be unusable for making comparisons. Using spiked proteins in a way that allowed us to control the total protein amount per lane, while only changing the amount of spiked proteins, we confirm that nonlinearity and saturation of densitometry data, and errors introduced from normalisation processes, can occur in routine assays that compare equal amounts of lysate. These findings apply to all Western blot studies, and we highlight quality control checks that should be performed to make Western blot data more quantitative.
Topics: Blotting, Western; Densitometry; Electrophoresis, Polyacrylamide Gel; Humans; Proteins; Reproducibility of Results
PubMed: 30800670
DOI: 10.1155/2019/5214821 -
Journal of Orthopaedic Research :... Mar 2023Computational fracture analysis has become a growing branch of orthopedic research. Particularly, the associated methods provide reliable tools for the analysis of 3D...
Computational fracture analysis has become a growing branch of orthopedic research. Particularly, the associated methods provide reliable tools for the analysis of 3D CT-based models of bone. This paper reports the results of such analyses for 15 human femora (healthy and osteoporotic) under different loading orientations (85 different analysis cases). A new method was developed for the calculation of the density distribution in the models from ordinary clinical CT images without calibration phantom. This method, along with a strain-energy-based linear finite element (FE) analysis scheme, was used to predict the fracture strength and pattern of 10 cadaveric femora, for which the mechanical testing results and calibrated FE models were already available. The very good agreement and consistency between different sets of results showed the reliability and accuracy of the new density calibration method, as well as the linear analysis scheme. Accordingly, the method was applied to five new clinical images, gathered from two clinics that used different scanners with different protocols. The strength and fracture pattern of each one of these specimens were analyzed under 15 different loading conditions. A consistent behavior was found for variation of the fracture load and pattern of all specimens with the loading orientations, while very clear contrasts were observed between the strength amplitudes of healthy and osteoporotic specimens. The proposed methods can be easily applied to ordinary daily (even archived) clinical CT scans to conduct fast and reliable fracture analysis of human femora for general bone research and opportunistic studies of osteoporosis and trauma.
Topics: Humans; Reproducibility of Results; Fractures, Bone; Femur; Tomography, X-Ray Computed; Finite Element Analysis; Densitometry; Bone Density
PubMed: 35730428
DOI: 10.1002/jor.25404 -
Magnetic Resonance in Medicine Jan 2015Twenty years ago, theoretical developments were initiated to model the behavior of the NMR transverse relaxation rates in presence of vessels. These developments enabled... (Review)
Review
Twenty years ago, theoretical developments were initiated to model the behavior of the NMR transverse relaxation rates in presence of vessels. These developments enabled the MRI-based mapping of mean vessel diameter, microvascular density, and vessel size index with comparable results to those obtained by a pathologist. The transfer of these techniques to routine clinical use has been hindered by the unavailability of the required sequences, namely fast gradient-echo spin-echo sequences. Based on the increasing accessibility of such sequences on MRI scanners over recent years, we review the principles governing microvascular MRI, the validation studies, and the applications that have been tested worldwide by several teams. We also provide some recommendations on how to measure microvessel caliber and density with MRI.
Topics: Algorithms; Densitometry; Humans; Image Enhancement; Image Interpretation, Computer-Assisted; Magnetic Resonance Angiography; Microvessels; Reproducibility of Results; Sensitivity and Specificity
PubMed: 25168292
DOI: 10.1002/mrm.25396 -
Physica Medica : PM : An International... Aug 2022To develop and validate an automated segmentation tool for COVID-19 lung CTs. To combine it with densitometry information in identifying Aerated, Intermediate and...
Atlas-based lung segmentation combined with automatic densitometry characterization in COVID-19 patients: Training, validation and first application in a longitudinal study.
PURPOSE
To develop and validate an automated segmentation tool for COVID-19 lung CTs. To combine it with densitometry information in identifying Aerated, Intermediate and Consolidated Volumes in admission (CT1) and follow up CT (CT3).
MATERIALS AND METHODS
An Atlas was trained on manually segmented CT1 of 250 patients and validated on 10 CT1 of the training group, 10 new CT1 and 10 CT3, by comparing DICE index between automatic (AUTO), automatic-corrected (AUTOMAN) and manual (MAN) contours. A previously developed automatic method was applied on HU lung density histograms to quantify Aerated, Intermediate and Consolidated Volumes. Volumes of subregions in validation CT1 and CT3 were quantified for each method.
RESULTS
In validation CT1/CT3, manual correction of automatic contours was not necessary in 40% of cases. Mean DICE values for both lungs were 0.94 for AUTOVsMAN and 0.96 for AUTOMANVsMAN. Differences between Aerated and Intermediate Volumes quantified with AUTOVsMAN contours were always < 6%. Consolidated Volumes showed larger differences (mean: -95 ± 72 cc). If considering AUTOMANVsMAN volumes, differences got further smaller for Aerated and Intermediate, and were drastically reduced for consolidated Volumes (mean: -36 ± 25 cc). The average time for manual correction of automatic lungs contours on CT1 was 5 ± 2 min.
CONCLUSIONS
An Atlas for automatic segmentation of lungs in COVID-19 patients was developed and validated. Combined with a previously developed method for lung densitometry characterization, it provides a fast, operator-independent way to extract relevant quantitative parameters with minimal manual intervention.
Topics: COVID-19; Densitometry; Humans; Longitudinal Studies; Lung
PubMed: 35839667
DOI: 10.1016/j.ejmp.2022.06.018 -
Journal of Musculoskeletal & Neuronal... 2005Bone densitometric data are often difficult to interpret in children and adolescents because of large inter- and intraindividual variations in bone size. Here, we... (Review)
Review
Bone densitometric data are often difficult to interpret in children and adolescents because of large inter- and intraindividual variations in bone size. Here, we propose a functional approach to bone densitometry that addresses two questions: is bone strength normally adapted to the largest physiological loads, that is, muscle force? Is muscle force adequate for body size? The theoretical background for this approach is provided by the mechanostat theory, which proposes that bones adapt their strength to keep the strain caused by physiological loads close to a set point. Because the largest physiological loads are caused by muscle contractions, there should be a close relationship between bone strength and muscle force or size. The proposed two-step diagnostic algorithm requires a measure of muscle force or size and a measure of bone mineral content (BMC) at a corresponding location. The results can be combined into four diagnostic groups. In the first situation, muscle force or size is adequate for height. If the skeleton is adapted normally to the muscle system, the result is interpreted as "normal". If it is lower than expected for muscle force or size, a "primary bone defect" is diagnosed. In the second situation, muscle force or size is too low for height. Even if the skeleton is adapted adequately to the decreased mechanical challenge, this means that bone mass and presumably strength are still too low for body height. Therefore, a "secondary bone defect" is diagnosed. It is hoped that the more detailed insights thus gained could help to devise targeted strategies for the prevention and treatment of pediatric bone diseases.
Topics: Adolescent; Algorithms; Bone Density; Bone Development; Bone Diseases; Child; Densitometry; Female; Humans; Male; Muscle Contraction; Muscle, Skeletal; Puberty; Stress, Mechanical; Weight-Bearing
PubMed: 16172514
DOI: No ID Found -
Acta Pharmaceutica (Zagreb, Croatia) Mar 2021The influence of different chromatographic conditions and the process of spot visualization on determining the limit of detection as well as quantification (LOD and LOQ)...
The influence of different chromatographic conditions and the process of spot visualization on determining the limit of detection as well as quantification (LOD and LOQ) of meloxicam by TLC-densitometric technique was estimated. Of all chromatographic conditions tested, the lowest limiting values, thus the best sensitivity, in the NP-TLC system was achieved on silica gel 60F254 and neutral aluminum oxide plates developed with the mobile phase consisting of ethyl acetate/toluene/n-butylamine (2:2:1, V/V/V). In the case of the RP-TLC method, a mixture of methanol/water (8:2, V/V) enabled densitometric detection of meloxicam at the lowest concentration level on RP-8F254 and RP-18F254 plates. Additionally, the smallest LOD value of meloxicam ensured crystalline violet and gentian violet as visualization agents on silica gel 60F254 and neutral aluminum oxide 150F254 plates, resp. Comparison of the densitometrically obtained spectra of meloxicam drug and its standard after the use of appropriate visualization agents could be a good and cheap alternative tool for the identification of meloxicam as an active pharmaceutical ingredient.
Topics: Chromatography, Thin Layer; Cost-Benefit Analysis; Densitometry; Indicators and Reagents; Limit of Detection; Meloxicam; Reference Standards; Reproducibility of Results
PubMed: 32697743
DOI: 10.2478/acph-2021-0006