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PubMed1989

Potential use of bioelectrical impedance of the 'whole body' and of body segments for the assessment of body composition: comparison with densitometry and anthropometry.

The value of 'whole body' and segmental impedance measurements, and of simple anthropometric methods for predicting body composition was assessed in 24 normal (14m, 10f) subjects (BMI, 18.3-28.6), using densitometry as the reference method. The contribution of segmental impedance was assessed in a separate group of 24 normal (12m, 12f) subjects (BMI, 19.8-28.8) at two frequencies (1 kHz and 50 kHz). Estimates of specific resistivities of certain individual segments (upper arm, forearm, upper leg, and lower leg) were also made in this group, and compared to those obtained from a group of 7 obese female subjects (BMI, 32.6-56.1). The bias and 95 per cent limits of agreement between densitometrically determined body composition (fat and fat-free mass, and total body water) and the alternative methods were found to vary considerably, depending on the technique and/or equations employed. Estimates of whole body composition based on impedance or resistance measurements were found to be associated with only slightly smaller limits of agreement than those made by anthropometry. The upper limb was found to have the greatest influence on whole body impedance measurements. Indeed, the forearm, which accounts for 1.3 per cent of body weight contributes 25.0 per cent to 'whole body' impedance. The estimated specific resistivities of segments were found to be considerably greater in the obese individuals than in normal female subjects (for example, 75 per cent higher for the upper arm, P less than 0.001). The results suggest that: (a) there may be a systematic, population-related, error in predicting densitometric estimates of body composition with the use of standard equations, which incorporate variables such as weight, height, skinfold thicknesses, and impedance/resistance measurements; (b) in this population, impedance or resistance measurements confer only a small advantage over simple anthropometry for predicting body composition; (c) the impedance of the arm or leg may provide a simple alternative method for assessing the composition of the whole body; and (d) the estimated specific resistivity of individual body segments may be useful for assessing the composition of those segments.

Adult↗
PubMed1989

[The diagnosis of cholecystitis by ultrasonic densitometry].

Ultrasound densitometry was used to determine echo density of the wall and contents of the gallbladder in normal persons and in patients suffering from cholelithiasis and chronic calculus-free cholecystitis. In patients with cholelithiasis, the gallbladder was later removed, followed by histological examination of its wall. The ultrasound and histological data were studied and compared. The highly significant differences in the echo density of the wall and contents of the gallbladder were obtained in normal persons and patients afflicted with chronic cholecystitis.

Adult↗
PubMed1989

[Dual-photon densitometry of the lumbar spine. Basic experience and results].

The principle of assessment of absorption of gamma radiation (single photon radiation, i.e. with one radiation energy) was first applied to assess the content of mineral substances in peripheral bones. Earlier and more marked affection of the spine in osteoporosis led to the development of dual-photon densitometry, i.e. differential assessment of the absorption of gamma radiation with two energies, which makes it possible to eliminate the ratio of soft tissues in absorption of the radiation (the source of radiation is gadolinium 153Gd). The equipment is more complicated and more expensive, the operation more time consuming and more pretentious. Various circumstances - most frequently changes of the spine with foci of increased density - make it difficult or impossible to evaluate and use the results in one third of patients with disorders of the bones (most frequently osteoporosis), incl. 1/2 of the patients above 60 years of age. Short-term reproducibility of the estimations is satisfactory - variation coefficients of repeated measurements in g.cm-1 and in g.cm-2 are less than 2%. Examination of 183 controls (83 men, 100 women) indicates a drop of the mineral content in L2 to L4 with age in women from 25 to 30 years to old age with a slight acceleration during the menopause, in men a decline only after the age of 60 years. In younger age groups the scatter of our normal values in men is greater than in women. The bone density in g, g.cm-1 as well as in 9.cm-2 rises significantly in the order L2 less than L3 less than L4. Except for the limited applicability of results the basic experience is on the whole favourable. From the clinical aspects the evaluation of pathological findings, to which a separate paper will be devoted, is of decisive importance.

Adult↗
PubMed1989

A comparative study of CT densitometry of vertebral cancellous bone, abdominal aorta, paravertebral fat and the relative fat volume.

Fluctuations are observed in CT densitometry of cancellous bone of the lumbar vertebra in relation to age and sex and also per age/sex group. An investigation was carried out in 119 patients to possibly detect comparable fluctuations in CT measurements of other tissues. The spongiosa of the fourth lumbar vertebra, the abdominal aorta, paravertebral fat and the ratio fat volume/total irradiated volume were compared in the slice plane through the middle of the fourth lumbar vertebra. Calibration was performed using a water phantom. A correlation between the mentioned parameters could not be demonstrated. The relation between Bone Mineral Density (BMD) and age and sex showed the same values as known from the literature, being representative for a normal population. Using the aorta as a reference (which in fact is related to water) a similar curve is found as in Cann and Cann et al. The density of the aorta showed a constant value, varying between 38 and 50 HU with a mean of 45 HU. Extreme values were only found with streak artefacts. It seems useful to use the aorta values as a reference to measure the relative value of vertebral cancellous bone.

Adipose Tissue↗
PubMed1989

[Determination of choleretic constituents in Artemisia scoparia Waldst. et Kit. by TLC densitometry].

In the present paper, a quantitative method for determining the main choleretic components (chlorogenic acid, p-hydroxyacetophenone and scoparone) in Artemisia scoparia Waldst. et Kit. by TLC densitometry was developed. The concentrated methanolic extract was spotted on to a home-made silica gel G plate The plate was developed stepwisely, first with chloroform-ethyl acetateformic acid (2:2:1), then with cyclohexane-ethyl acetate (1:1). The three components were well separated. The spots were scanned with a Shimadzu CS-910 TLC scanner, by reflection mode and linear scanning. The linear relationship between the amount of the three components and peak area was obtained, but it did not go through the origin; so a two-point external standard method was used in the determination. Various samples of different collecting seasons and different parts of the plant were assayed.

Acetophenones↗
PubMed1977

[The use of an internal standard for the correction of deviations in densitometry of thin-layer chromatograms (author's transl)].

In order to obtain a better reproducibility in quantitative determination of amino acids in amounts of picomoles an internal standard was used. A mixture of ten amino acids was diluted and dansylated. 0.1 microliter of each solution was separated by two-dimensional thin-layer chromatography on polyamide sheets (3 x 3 cm). Each chromatogram was photographed with four different exposure times under ultraviolet light. The dark spots in the photographic negatives were measured by television densitometry. A number of factors influence the reproducibility of this method: loading volume, photographic exposure time and processing, and quenching of fluorescence. As an internal standard, which is influenced by all these factors, DANS-hydroxyproline was added to each solution. By using this standard, the variations in exposure time and fluorescence quenching can be corrected satisfactorily. The relative standard deviation of the mean value of four photographs of one chromatogram is 2%. The results on correction of the volume deviation were not so satisfying. The relative standard deviation of the mean of twelve different chromatograms can be reduced from 34% for the initially measured data, to 8% for the values corrected by the internal standard. It seems necessary to carry out three or more determinations of one solution. In this case the relative standard error of the mean is 2%.

Amino Acids↗
PubMedDate not supplied

Densitometry of the cochlear capsule and correlation between bone density loss and bone conduction hearing loss in otosclerosis.

Radiodensity of the bony cochlear capsule was investigated by CT-scanning in 134 ears with otosclerosis and 35 normal control ears. A technique of densitometry of the cochlea was developed comprising the measurement of maximum and minimum density together with mapping of the cochlea and measurement of the density at six predefined points in the cochlear capsule. Bone density in the normal cochlea showed very little interindividual variation. In the otosclerosis patients, minimum density was decreased in 58% of the ears, indicating the presence of a focus. At visual examination, foci were only detectable when density loss exceeded 200 Hounsfield. A positive correlation was found between bone density loss and bone conduction hearing loss with a maximum at 2,000 Hz and the medioventral point of the cochlear wall. The method appears to be useful for the follow-up during fluoride treatment, as is demonstrated by a case report.

Cochlea↗
PubMed1985

[Rapid analysis of transferrin-iron complexes by isoelectric focusing and radioactive densitometry on gel].

The analysis of the molecular forms of transferrin-iron complexes with 59Fe, was carried out using an isoelectric focusing method on commercially available polyacrylamide plates (PAG plates pH = 4-6,5, LKB). Depending upon the saturation degree of proteins with iron, apotransferrin (pI = 6,1), transferrin-Fe3+ (pI = 5,8), transferrin-2 Fe3+ (a) (pI = 5,5) and transferrin-2 Fe3+ (b) (pI = 5,3) were put forward. When the protein was saturated with iron, a double band was observed which was assigned to the microheterogeneity of the protein and depends upon the sialic content. The quantitative analysis was carried out by studying 59Fe radioactivity distribution directly on the plate. As a control, a specific staining of proteins was achieved. The interpretation of the results is difficult if such a method is used, as some bands are not attributed. Through an unspecific staining, the UV-visible densitometry is not satisfactory enough. The proposed method allows a fast analysis of transferrin-metal complexes labeled with radioactive metals. Such a method would be adaptable to the study of other complexes as transferrin-67Ga, transferrin 111In in order to determine the binding site of metal on the protein and its metal content.

Densitometry↗
PubMedDate not supplied

Densitometry of aflatoxin thin-layer chromatograms performed by computer-assisted spectrofluorometry.

A system consisting of an SPF-500 (Aminco) spectrofluorometer interfaced to a Felix-M18 microcomputer was used for the fluorescence densitometry analysis of aflatoxin fractions separated by silica gel thin-layer chromatography. The efficiency of fluorescence densiotmetry ultramicroanalysis was dependent on the type of aflatoxin (B1, B2, G1, G2 or M1) and on the nature of the contaminated sample.

Aflatoxins↗
PubMed1985

[Bone densitometry by monochromatic photon absorption. Study of a normal population and values obtained in various pathological conditions].

Monophotonic absorption densitometry of the forearm is an exact method for the evaluation of the bone mineralisation, provided the positioning of the forearm is strictly controlled. It is also able to demonstrate progressive enlargement of the bones with age, up until the ages of about 60 to 70 years. The measurements should be performed in two sites: diaphyseal (cortical bone) and epiphyseal (cortical and trabecular bone). The curves obtained from 1,011 controls are in agreement with the current state of knowledge concerning the variations in bone mass during life in both sexes. In women, the number of pregnancies has no influence on the mineralisation index (MI). The values obtained in 156 osteoporotic patients and in 53 subjects with idiopathic hypercalciuria were appreciably lower than those obtained in age-matched controls. In individual subjects, this method appears to be much more discrimination than the measurement of the trabecular bone volume (TBV) for the diagnosis of osteoporosis and no statistically significant correlation was observed between the MI and the TBV. In male controls, there was a depression of the mean curves around the age of 45 years in all four sites of measurement. This depression was also observed in male subjects with hypercalciuria. They correspond to the generations born between 1930 and 1940. The responsibility of a relative nutritional deficiency affecting growing boys during the 1939-45 war is proposed.

Adolescent↗
PubMed1978

Quantitative determination of carbaryl in apples, lettuce, and water by densitometry of thin layer chromatograms.

A method for the quantitative determination of carbaryl insecticide by in situ densitometry was developed. After separation on silica gel thin layer plates, carbaryl residues were detected by using p-nitrobenzenediazonium fluoborate reagent and quantitated by scanning the resultant blue spots with a fiber optics densitometer and comparing them with standards. The method was applied to water fortified with carbaryl at 8 ppb and apples and lettuce fortified at 0.10 ppm; all recoveries were greater than 89%. The 2 crop extracts were cleaned up by using the AOAC thin layer chromatographic method for visual estimation of carbaryl. Related carbamate insecticides were detected by using the same reagent, and the potential for quantitation was demonstrated.

Carbaryl↗
PubMed1973

Quantitative analysis of unconjugated and conjugated bile acids in duodenal fluid by densitometry after paper electrophoresis.

A new paper electrophoretic method for the separation of bile acids into five groups, (1) unconjugated, (2) glycine conjugates and (3) taurine conjugates, and (4) and (5) the respective monosulfates, is described. Rapid and accurate qualitative and quantitative estimations of each group are obtained by densitometry after internal standardization and phosphomolybdate color development. The technique can be done in the routine clinical laboratory and is useful for the detection of diseases affecting the enterohepatic circulation of bile acids.

Bile Acids and Salts↗
PubMed1979

[Phenobarbital determination using direct densitometry of thin-layer chromatography].

A report on the determination of phenobarbital in model specimens of plasma and blood using direct densitometry of thin-layer chromatograms, namely by measurements of fluorescence quenching using remission technique following previous conversion of phenobarbital to sodium salt. Phenobarbital is extracted by three fundamentally different techniques, the results of estimation are given statistical evaluation, and the yield of each of the techniques is compared. Since the processing of 1 ml serum still allows the estimation of quantities as low as 1 microgram per stain the proposed method can be recommended for the determination of toxic levels of phenobarbital in plasma or in blood.

Chromatography, Thin Layer↗
PubMed1979

Quantitative determination of tris-(2,3-dibromopropyl) phosphate by densitometry of thin layer chromatograms.

The flame retardant tris-(2,3-dibromopropyl) phosphate (Tris) was chromatographed on silica gel thin layer plates, using ethyl acetate-hexane (30+70) as the developing solvent. Tris was visualized by spraying the chromatogram with 1% aqueous silver nitrate followed by exposure to ultraviolet light for 40 min. Tris appeared as dark gray spots on a white background; the spots were quantitated by densitometry at 660 nm. The lower level of sensitivity was 50 ng; calibration plots were linear from 50 to 800 ng. The procedure was developed to determine the levels of unmetabolized Tris remaining after exposure to sewage sludge suspensions. Recovery of Tris from 3 sewage sludge samples fortified at the 1.0 ppm level averaged 97%.

Chromatography, Thin Layer↗
PubMed1977

[Value of photon-absorption densitometry for the assessment of bone density].

Senile osteroporosis itself is asymptomatic unless pain is induced by the static insufficiency of the skeleton, in long lasting disease. Conventional procedures for early diagnosis and control of patients are invasive and therefore not suitable for routine purposes. The efficiency of sodium fluoride for the treatment of senile osteoporosis after a minimum of 12 months has been established by invasive methods. It is the purpose of this study, to examine the value of photoabsorption-densitometry with double-isotope-method (125-J, 241-Am) for the evaluation of a therapeutic effect in this disorder. 7 patients with clinical and radiological evidence of senile osteoporosis (6 female, 1 male patient with ages of 56 to 87 years) underwent regular follow-up examinations for one year while on a regimen of 25mg. sodium fluoride, as retard, twice daily. The bone mineral content registered 1 cm. proximal of the proc. styloideus ulnaris (representative for the trabecular bone) and 8 cm proximal from the proc. styloideus ulnaris of the right forearm (representative for cortical bone) was not statistically different from the measurements registered prior to the study. However, the bone mineral content registered in both regions increased significantly, after 12 months treatment (p less than 0.05). This indicates that the assessment of bone mineral content by photonabsorptiondensitometry is a valuable method for therapeutic control of this disorder. The method is recommended as a routine procedure for the early diagnosis and for follow up of sodium fluoride therapy geriatric patients.

Aged↗
PubMed1982

Lymphocyte proteins in Huntington's disease: quantitative analysis by use of two-dimensional electrophoresis and computerized densitometry.

We used quantitative two-dimensional electrophoresis to study lymphocyte proteins in Hungtington's disease. Three hundred and six polypeptides from 14C-labeled, phytohemagglutinin-stimulated lymphocytes were measured for variation in relative spot density and 186 for variation in spot position by use of a computer program requiring operator interaction. Each polypeptide was measured in a total of 30 electrophoretograms from 28 individuals, including 13 with Huntington's disease, 2 at risk for it, and 13 controls. The study included two sets of identical twins and, as neurological controls, individuals with neurofibromatosis, Alzheimer's disease, or Shy-Drager syndrome. Seven protein polymorphisms were identified among the 186 most dense polypeptides of each gel, corresponding to a minimum average heterozygosity of 1.4%. Stringent criteria were used to define polymorphic proteins, including observation of at least one individual with each of two homozygous phenotypes and one with the heterozygous phenotype, demonstration of the expected gene dosage relationship by quantitative densitometry, consistency with genetic relationships, and reproducibility. One polymorphic protein showed three electrophoretically variant alleles. Our identification of seven polymorphisms among the 186 proteins measured on a single electrophoretogram illustrates the potential of this technique for performing linkage analysis in diseases of genetic origin. However, we observed no quantitative or positional protein variations that were characteristic of (i.e. specific for) Huntington's disease.

Blood Proteins↗
PubMed1984

Idiopathic osteoporosis in a three-year-old girl. Follow-up over a period of 6 years by computed tomography bone densitometry (CT).

In a girl suffering from idiopathic transient osteoporosis the development of vertebral deformation and recovery could be followed from the age of 3.4 to 9.3 years. Computed bone densitometry (CT) revealed values below normal for trabecular bone density (-2.6 SD at 4.3 years and -2.8 SD at 5.3 years) during the clinically symptomatic phase of the disease and normalization after the age of 6 years (-0.2 SD at 6.7 and 9.3 years). Cortical bone mineral parameters measured by CT and metacarpal bone measurements from conventional X-rays showed values at the lower range of normal and only a weak correlation with clinical symptoms, vertebral deformation and recovery, respectively. CT may probably allow to diagnose osteoporosis before the appearance of deformities or fractures; in milder forms of osteoporosis the diagnosis may be possible by CT only.

Bone Development↗