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PubMed1978

[Attenuation values of normal and pathological liver tissue as a basis for computer tomographic densitometry of fatty livers (author's transl)].

Measurements of the density of normal and diffusely disease liver parenchyma show a significant difference only in the presence of fatty livers. A linear relationship between the fat content and density (g/cm3) has been demonstrated. Computer tomographic densitometry of liver tissue correlates well with physical in vitro measurements and permits measurements of fat content which are sufficiently accurate for clinical use. Other types of liver disease cannot be differentiated by densitometry.

Absorptiometry, Photon↗

PubMed1978

Determination of individual hydroxyethyl rutosides in various animal body fluids by thin-layer chromatography and scanning densitometry.

A method is described for the accurate determination in plasma of the beta-hydroxyethylrutosides by measurement of the fluorescence of their borocitrate complexes by scanning densitometry following separation by thin-layer chromatography. A modification is also described for estimation of individual hydroxyethylrutosides and their glucuronide conjugates in samples of bile and urine.

Animals↗

PubMed1975

[Quantitative determinaton of glycerides by densitometry (author's transl)].

After determination of charring conditions and the measurement by densitometry of lipids separated by thin-layer chromatography, a statistical analysis was performed to determine the significance of the results. Calibration curves were studied and response factors calculated for some saturated and unsaturated triglycerides.

Chromatography, Thin Layer↗

PubMed1975

An improved method for the quantitation of A2 hemoglobin utilizing cellulose acetate electrophoresis and densitometry.

An improved method of A2 quantitation by cellulose acetate electrophoresis is describes. Densitometry is performed on uncleared membranes. The height of the peak obtained for the A2 band is compared with a standard curve derived from peaks obtained by serial dilutions of hemoglobin. Noral A2 hemoglobin as measured by this method is 2.55 percent plus or minus 0.60 (2 S.D.). Twenty patients samples were run in parallel with a column chromatographic method. Eight samples were found to contain elevated A2 levels by the column method. The same eight samples were correctly identified by the electrophoretic technic.

Blood Protein Electrophoresis↗

PubMedDate not supplied

Ultrasonic pulmonary Densitometry: preliminary studies.

The feasibility of using A-mode ultrasound to measure lung density changes was tested in two studies. (A) Wet sponges were used as experimental analogs of the lung. The sponges were weighed. A-mode recordings were obtained by placing the transducer face against a sheet of film in contact with each sponge. Ultrasound penetration increased directly with increasing water content. The range of densities studied corresponds with that which occurs in normal and edematous human lungs. In a second study (B), the depth of ultrasound penetration into 3 postmortem human lungs was measured at increasing levels of inflation by positive intrabronchial pressure. Ultrasound penetration decreased approximately logarithmically with increasing inflation pressure. These relationships indicate a potential application of ultrasound to pulmonary densitometry. This could provide a noninvasive means for clinical estimation of changes in lung water, without the use of ionizing radiation.

Body Water↗

PubMed1979

An objective method for measuring fluorescence of individual sperm cells labelled with 1-anilinonaphthalene-8-sulphonate (ANS) by means of photomicrography and densitometry.

A method is presented for measuring the degree of fluorescence of sperm cells labelled with 1-anilinonaphthalene-8-sulphonate (ANS). Labelled spermatozoa were subjected to incident-light u.v. illumination and the fluorescent image was photographed. Densitometry of the photographic film yielded values for individual sperm heads, and the mean value for ten cells formed the unit of data for parametric statistical analysis. The method is both objective and precise, and was used to distinguish between treatments applied to the spermatozoa. It is believed that the method has a wide application as an inexpensive means of fluorimetry.

Anilino Naphthalenesulfonates↗

PubMed1975

I. Validity of dichnomatic earpiece densitometry for quantitative studies in children with shunt-free cardiovascular malformations.

Cardiac output was assessed in 16 children without evidence of cardiovascular shunts from simultaneously recorded earpiece and cuvette densitometric tracings. The earpiece set-up was calibrated by the end-tail method. Both instruments gave linear response to dye concentrations used. There was a close correlation between cardiac output figures recorded by the two methods (r equal to 0.95) and no systematic difference occurred. It is concluded that in infants and children earpiece densitometry constitutes a rapid and accurate method for quantitative circulatory studies.

Adolescent↗

PubMedDate not supplied

Geometrical considerations for Compton scatter densitometry.

The determination of the physical density by Compton scatter densitometry is dependent upon the geometry used for the measurement. The diameter of the sample, the density range, and the scattering volume size and shape influence the relative electron density values obtained by such a system. This work presents the results of an experimental analysis of these parameters in which the importance of each is evaluated for samples of known density. A bias in the computed Compton density, due to multiple scattering and attenuation, is defined; and an expression relating the density bias to these geometrical parameters is presented. The importance of applying corrections to the computed physical density for samples of large diameter and/or high density (cortical bone tissue and large diameter cancellous bone tissue) is discussed.

Bone and Bones↗

PubMed1979

Bone densitometry using computed tomography. Part II: increased trabecular bone density in children with chronic renal failure.

The method of gamma-ray computed tomography (gamma-ray CT) bone densitometry described in the preceding article provides selective determination of trabecular bone density (TBD), the relative amount of compact bone (bone density, BD), and the total absorption (TA) within a bone cross section. Seven of nine children with chronic renal failure (CRF), and selected only on the basis of their serum creatinine value (greater than 5 mg/100 ml), had increased TBD values above the normal range, whereas the other bone mineral parameters were normal. Radiographic signs of secondary hyperparathyroidism (subperiosteal erosions, cysts) were reported in the five patients with the highest TBD values, whereas the subjective diagnosis of osteosclerosis reported in three of these five and in one other patient correlated less well with the TBD increases. However, this is the first report of an objective, non-invasive documentation of the radiological finding of osteosclerosis in CRF. It also explains why methods for bone mineral measurements used previously, such as a photon absorptiometry which provides only a parameter equivalent to TA, failed to reveal increases in bone mineral content in renal osteodystrophy even when signs of osteosclerosis were present. Thus, gamma-ray CT helps to document objectively the degree of osteosclerosis and its location.

Adolescent↗

PubMed1975

Quantitative determination of drugs by means of densitometry of thin-layer chromatograms. Part 4: Determination of vitamins A and E in pharmaceutical preparations.

A quantitative method for the determination of vitamins A and E is proposed based on the direct densitometry of thinlayer chromatographic spots. An appropriate solvent system for the chromatographic separation of the vitamins and the conditions under which a linear relationship between the absorbed light and the logarithm of concentration exists (1--10 mug range) are found. The precision of the method is evaluated by a statistical treatment of the results. Satisfactory reproducibility is established-- the variation coefficient for the determination of the two vitamins is about 4--5%. The method is applied for the analysis of oil and aqueous injection solutions, mixtures containing the three vitamins A, E and D2 and some pharmaceutical preparations (Pharmavit¿ and Devitforte¿). The presence of the decomposition products and other substances (other pharmaceuticals, stabilizers, solubilizers etc.) does not affect the determination. The analysis is performed without preliminary treatment of the sample.

Chromatography, Thin Layer↗

PubMed1975

Quantitative determination of drugs by means of densitometry of thin-layer chromatograms. Part 5: Determination of the Vitamins B1, B2, B6 and B12 in mixture and in pharmaceutical preparations.

A quantitative t.l.c. densitometric method for the simultaneous determination of the water-soluble vitamins B1, B2, B6, and B12 is proposed. The four vitamins are determined on one and the same plate by direct densitometry of the t.l.c. spots. A preliminary separation of the vitamins one from another, as well as a preliminary separation from other pharmaceuticals is not necessary. The determination is performed quickly and easily. The relative standard deviations of a single determination are the following: for thiamine 6,6%, for riboflavin 5,5%, for pyridoxine 6,4%, and for cyanocobalamin 5,8%. The proposed method is applied to the determination of B-vitamins in three pharmaceutical preparations: ampoules B12 with B1, ampoules B-complex, and antisclerol dragee. The presence of other pharmaceuticals (vitamins C and PP, urethane, aminophenazone, phytin, rutin, theobromine, etc.) does not interfere with the determination.

Chemistry, Pharmaceutical↗

PubMedDate not supplied

Mapping size distributions of parenteral fluorocarbon emulsions by a novel method of centrifugal sedimentation followed by densitometry.

A novel method for characterization of size distributions of parenteral fluorocarbon emulsions is described. Prepared emulsions were centrifuged to sediment droplets above predetermined diameters out of a known supernatant sample volume using the Bostok-Stoke's equation. Centrifugation times may be calculated using centrifuge parameters and physical properties of the fluorocarbon oil phase and the dispersion medium. The fluorocarbon content of the supernatant sample volume at successive centrifugation times was determined both by densitometry and by Gas Chromatography. A close correlation was found between the two methods. The density data was processed and converted into a volume distribution histogram by means of a program written in BASIC. The speed, simplicity of use, non reliance on costly equipment and good correlation to absolute particle counting methods makes the density method suitable for submicron size characterization.

Centrifugation↗

PubMed1992

Photographic densitometry for quantitative DNA analysis of cytologic and histologic specimens.

We found that photographic densitometry (PD) is a useful technique for quantitative determinations of nuclear DNA content in clinical tumor material. Optimum conditions for the use of PD in clinical cytology and histopathology were worked out. A quantitative evaluation of the method was performed, particularly with respect to errors that may appear when measuring clinical tumor material. Our study showed that PD offers accurate DNA measurements in cytologic and histologic specimens. Ploidy level determinations in tumor cell populations in clinical material could be as accurately performed with PD as with scanning microspectrophotometry (SMP). Nuclear DNA content of individual cells as determined by PD correlated highly with nuclear DNA content determined by SMP (correlation coefficient, 0.96). Since the PD method is less influenced by background variation than are other image techniques (due to measurement of a photographic image), it is particularly useful in measurement of histopathologic sections, in which the background variation can introduce considerable errors. The method is also valuable with clinical cytologic smears, in which the presence of blood and other material disturbs the background. PD represents a valid complement to scanning microspectrophotometry and TV imaging systems, particularly for DNA analysis of tissue sections. Moreover, it can be applied easily in the clinical routine. Relevant tissue areas are selected and photographed by the pathologist or cytopathologist, and the measurement is performed by a laboratory technician.

Cell Nucleus↗

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↗

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↗

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↗