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PubMed1990

Blood-brain barrier injury following intracarotid injection of radiographic contrast media. In vivo quantification using magnetic resonance imaging and Gd-DTPA.

Changes in signal intensity of the brain at magnetic resonance (MR) imaging before and after Gd-DTPA were used for in vivo quantification of injury to the blood-brain barrier (BBB). Immediately following intracarotid injection of 2 ml/kg of radiographic contrast medium (CM) 0.4 mmol/kg of Gd-DTPA was injected intravenously. MR imaging was performed with a 400/25 partial saturation pulse sequence. The maximum percentage changes (mean +/- SD) in signal intensity of the brain after CM and Gd-DTPA were 1.6 +/- 1.6% with saline, 3.2 +/- 2.0% with iotrolan, 4.3 +/- 1.7% with iohexol, 6.6 +/- 3.6% with ioxaglate and 8.2 +/- 3.6% with diatrizoate. Not only the osmolality but also the ionicity and chemotoxicity seemed to influence Gd-DTPA leakage. A subtle BBB injury had a stronger tendency to occur in the basal ganglia than in the cerebral cortex. MR enhancement is proposed as a sensitive method for in vivo quantification of the BBB injury caused by intracarotid CM injection.

Animals↗
PubMed1990

SPECT dual-energy-window Compton correction: scatter multiplier required for quantification.

The dual-energy window Compton-scattering correction technique is defined here especially for accurate quantification of focal regions having higher than average uptake. The quantification is relative to a known-activity reference source. The scatter multiplier ("k" value) is determined for a radioactive 99mTc sphere on or off the axis of a cylinder containing water with or without background. Both maximum likelihood and filtered-backprojection reconstruction are employed. Either projections or tomograms are corrected. With tight regions of interest, there is a tendency for the requisite "k" value to be slightly lower as the diameter of the cylinder is increased. Neither sphere location nor background perturbs "k", however, so a constant value is a good, first approximation. Then a two-sphere validation test yields an accuracy of 8% with subtracted-tomograms ("k" = 1.30) and 2% with subtracted-projections ("k" = 1.20). With a reference-source region of interest which is four times larger, "k" is reduced and also now depends on background. Although equivalent quantitatively, maximum likelihood is preferable to filtered backprojection with Chang attenuation correction since it produces a less-noisy image.

Algorithms↗
PubMed1989

Flow cytometric reticulocyte quantification using thiazole orange provides clinically useful reticulocyte maturity index.

Flow cytometric reticulocyte quantification with thiazole orange has been reported to be of potential utility in a clinical hematology laboratory. We have instituted this technique into routine clinical testing for 18 months and we describe this experience. Flow cytometric analysis provided not only reproducible, cost-effective reticulocyte quantification, but a quantitative reticulocyte maturity index proportional to the amount of RNA in the reticulocytes. The reticulocyte maturity index measurement represents an independent parameter of erythropoiesis, which provided clinically valuable information regarding bone marrow engraftment in patients following autologous bone marrow transplantation. The findings of this study demonstrate the clinical utility of thiazole orange reticulocyte analysis and indicate the diagnostic importance of the reticulocyte maturity index measurement in the evaluation of erythropoietic activity.

Benzothiazoles↗
PubMed1989

Quantification of fibronectin in extracts of human aortae by an ELISA.

A procedure for extraction and quantification of fibronectin in human aortic tissue is described in this paper. Dried, defatted samples of human aortic tissue were subjected to sequential extraction with (i) 0.89% NaCl, 10 mmol/l Tris/HCl, pH 7.4, (ii) 5 mg/ml heparin, 2 mol/l urea and (iii) collagenase digestion. More than 75% of hexosamine-containing molecules were solubilized by this procedure. Immunoblotting of extracted proteins separated by SDS-PAGE showed that extracted fibronectin had a mobility in the same range as that of plasma fibronectin. Fibronectin ELISA performed on these extracts gave dilution curves parallel to the standard curve, the sensitivity was 2.7 micrograms/l. Recoveries of a fibronectin standard added to the NaCl, heparin/urea and collagenase solutions during extraction were 97%, 90% and 84% respectively. Normal aortic tissue from 31 patients was subjected to the sequential extraction scheme and fibronectin quantification in the various extracts demonstrated that 4.52 +/- 1.79 micrograms was dissolved in the NaCl extracts, 5.41 +/- 2.28 in the heparin/urea extract and 1.08 +/- 0.43 in the collagenase digest, respectively. (Values are expressed as micrograms fibronectin/10 mg dry, defatted tissue (mean +/- SD]. Our results indicate that the ELISA method can be applied for the measurement of fibronectin in extracts of human aortic tissue. This might be useful in the study of diseases where alterations in arterial fibronectin content may be expected.

Aged↗
PubMed1987

[Quantification of proteinuria by measurement of the protein/creatinine ratio].

Accurate quantification of urinary protein excretion is difficult due to problems in 24-hour urine collection. We have evaluated the value of the protein/creatinine ratio in one single urine sample. There was an excellent correlation between this ratio and the protein content of a 24-hour urine collection [Pu (g/24 h) = 11.7 Pu (g/l) Cr (mmol/l); r = 0.96; P less than 0.001]. The best correlation was found with the sample collected after the first voided morning specimen. In our experience the ratio is more accurate for the quantification of urinary protein excretion than measurement of protein excretion in the same urine sample and also determination of protein excretion in 24-hour urine collected under the usual ambulatory conditions. We suggest that the protein/creatinine ratio should be used in ambulatory and hospitalized patients, especially for multicentric clinical trials in nephrology.

Ambulatory Care↗
PubMed1988

Direct immunomagnetic quantification of lymphocyte subsets in blood.

A method is described where superparamagnetic polymer microspheres coated with monoclonal antibodies (MoAb) are used for the direct and fast quantification of the absolute number of cells of various lymphocyte subsets in blood. Blood samples were incubated with microspheres coated with a subset specific MoAb. Using a magnet the microsphere-rosetted cells were isolated and washed. Following lysis of the cell walls to detach the microspheres, the cell nuclei were stained with acridine orange and counted in a haemocytometer using an immunofluorescence microscope. With MoAb specific for CD2, CD4, CD8 and CD19, reproducible absolute counts of the corresponding lymphocyte subsets were obtained which correlated closely with those obtained by an indirect quantification method.

Cell Separation↗
PubMed1987

Functional analysis and quantification of the complement C3 derived anaphylatoxin C3a with a monoclonal antibody.

The C3 fragment C3a belongs to the anaphylatoxins. It has immune regulatory activity and contributes to the pathogenesis of the adult respiratory distress syndrome (ARDS). The low molecular weight (9 kD) of C3a complicates the production of antibodies to C3a. We obtained a monoclonal antibody (designated H13) to human C3a. It reacts with C3a or C3a-desArg and with native C3 but not with C5 or C5a. In immunoblot analysis it reacts with the alpha- but not with beta-chain of C3 and binds to a protein with a mol. wt of about 10 kD present in zymosan-activated sera which is only marginally detectable in nonactivated serum and absent in plasma. H13 crossreacts with the analogous proteins of rabbit, guinea pig and sheep. H13 has the capacity to bind 125I-radiolabelled C3a efficiently but fails totally to react with 125I-C5a or with other C3 alpha-chain fragments. H13 blocks C3a functional activity. It markedly inhibits C3a-induced 3H-serotonin release from platelets in vitro and similarly inhibits the C3a-induced extravasation of Evans blue into the skin in vivo. H13 does not interfere with the haemolytic activity of C3. An ELISA system was established using H13 which permits quantification of C3a in sera of polytrauma patients. The antibody H13 should facilitate further functional analysis of C3a in experimental systems. It should be useful for quantification of C3a in diagnostic assays and also for application in immunopathology.

Animals↗
PubMed1986

Computer-aided quantification of scalp hair.

In this article we present a statistical model that, when applied in conjunction with existing image analysis technology, allows for a precise quantification of two-component visual fields. Application of this methodology to the problem of quantification of hair density in patients with hair loss disorders yields excellent results. Under photographically controlled conditions this method should yield completely consistent and valid results. The complete absence of subjective bias in the application of this method makes it an extremely attractive alternative to existing procedures. Limitations to the use of this methodology are detailed, and an alternative approach is suggested.

Algorithms↗
PubMed1986

Quantification of methoxsalen-DNA adducts with specific antibodies.

Methods are now available for the quantification of carcinogen-DNA adducts in human tissues and can be used to screen populations for exposure to environmental carcinogens. One approach utilizes highly specific antibodies in sensitive immunoassays for quantifying adduct levels in DNA from various tissues. We have recently developed a panel of monoclonal antibodies that specifically recognize DNA modified by methoxsalen and ultraviolet A light (320-400 nm) (UVA). These antibodies have been characterized as to sensitivity and specificity by an enzyme-linked immunosorbent assay (ELISA). In a competitive ELISA, 50% inhibition of antibody binding occurred with 17 fmol methoxsalen-DNA photo adducts. There was also some antibody cross-reactivity with DNA modified by 4'-aminomethyl-4,5,8-trimethylpsoralen and 4',5-dimethylangelicin but not with free methoxsalen. A more sensitive ELISA has also been developed using fluorescence detection of enzyme activity. With this assay, one adduct per 10(8) bases can now be detected reliably. Adduct levels have been quantified in myeloma cells and lymphocytes treated in vitro with methoxsalen and UVA. In addition, in preliminary studies, adducts have been measured in lymphocytes isolated from patients undergoing extracorporeal photophoresis for cutaneous T-cell lymphoma. Quantification of methoxsalen adducts in patients should provide a basis for estimating risk resulting from psoralen plus UVA (PUVA) treatment.

Antibodies, Monoclonal↗
PubMed1987

[Cardiokymography: relative quantification of results in normal probands].

The main problem with cardiokymography (CKG) and the principal reason for its limited clinical application to date is the deficiency of calibration and quantification of results. We tried to improve the value of the procedure by quantification of the results in 14 healthy young men (age: 23, 18-31 years) in place of subjective assessment. Before and after a bicycle exercise stress test CKG tracings were obtained in a lying position at rest, immediately after exercise and after recovery. Two different methods were applied to quantify the CKG tracings (distance method and area method). The relative height of the curves at rest was 89 +/- 72% (68 +/- 39%), immediately after exercise 111 +/- 60% (73 +/- 27%) and, after recovery 121 +/- 88% (78 +/- 49%). The relative change in the height of the curves between rest and exercise was not significant according to both methods (+22 +/- 64%/+5 +/- 32%), but the variation of values in an individual patient between rest and exercise was large. Interobserver variability was rather large, according to two independent investigators. Hence, it was not possible to establish limits of normal values in quantitative CKG, but only mean values.

Adult↗
PubMed1986

Pressure threshold meter: its use for quantification of tender spots.

The pressure threshold meter (PTM) and its use for evaluation of tender spots and trigger points are described. Pressure threshold is the minimum pressure inducing pain or discomfort. The PTM consists of a force gauge (11 kg range) to which a rubber disc with lcm2 surface is attached. This surface has been proven adequate for quantification of deep tenderness in soft tissues. Normal threshold values were established in 50 volunteers, 24 men and 26 women, at nine different sites frequently affected by trigger points, including the trapezius, supraspinatus, infraspinatus, teres major, lumbar paraspinals (2 sites), gluteus and pectoralis muscles. The deltoid, where muscle sensitivity is usually normal, was used as a reference. PTM is used clinically for quantification of tenderness for medicolegal purposes, but primarily to prove the presence of trigger points to patients and health professionals. Reaction to various forms of treatment such as physiotherapy and drugs can be assessed quantitatively. When trigger point injections are properly administered to affected areas, pressure threshold measurements usually increase by 4 kg/cm2. Failure to increase the reading indicates that the injection was incomplete and the procedure should be repeated. The PTM can be used for monitoring tenderness, inflammation, arthritis activity, and fibrositis.

Equipment Design↗
PubMed1987

Urinary organic acids: isolation and quantification for routine metabolic screening.

A method for isolating organic acids from acidified urine on an equivolume mixture of Porapak Q and Porapak T is described, and results are compared with extraction with ethyl acetate and ion exchange on DEAE-Sephadex. Average recoveries of 14C-labeled oxalic acid, lactic acid, succinic acid, alpha-ketoglutaric acid, citric acid, and cinnamic acid were equal to or better than those obtained with the solvent-extraction method. The ion-exchange method gave higher recoveries for oxalic acid, lactic acid, and citric acid. The quantification of separated acids from reconstructed mass spectrometric ion traces is compared with quantification from the simultaneously recorded flame ionization detector response signals. A good correlation was obtained. With the present routine metabolic screening method we have detected several patients with inborn errors of metabolism.

Acetates↗
PubMed1985

[Detection, quantification and localization of myocardial infarcts: comparison of thallium single photon emission computer tomography with biplane angiography].

Thallium-201 single photon emission computed tomography (SPECT) is a new method for the scintigraphic visualization of the left ventricular myocardium. With SPECT a three-dimensional imaging by computerized slicing of the myocardium in various axes is possible. To investigate the capabilities of this new imaging technique, detection and quantification of remote transmural infarctions were compared with ventriculographic, coronarographic and electrocardiographic findings. 31 of 80 investigated patients had had a prior myocardial infarction. The left ventricular myocardium was divided into 7 regions in the scintigraphic as well as in the angiographic studies. In a total of 560 segments the sensitivity of SPECT for infarct detection was 87.5% with a specificity of 99.8%. Infarcts which were not detected scintigraphically were relatively small (mean 13.5% of the circumference). To quantify the infarct, the size of the defect was determined scintigraphically from a sagittal long axis and two short axes, and the images compared with angiographic infarct sizes (% of the circumference) according to the method of Feild et al. A good correlation without overestimation of the size by one method (SPECT defect = 0.93 X ventriculographic defect - 1.2%; r = 0.7, p less than 0.001) was obtained. Also a good separation of the perfusion areas of the coronary arteries due to the three-dimensional imaging with SPECT was possible. Thus, by employing Thallium-201 SPECT of the left ventricular myocardium exact localization and quantification of transmural myocardial infarcts with a positive predictive value of 98% can be achieved.

Coronary Disease↗
PubMed1986

Evaluation of absorption and first- and second-derivative spectra for simultaneous quantification of bilirubin and hemoglobin.

We discuss the relative merits of absorption and first- and second-derivative spectra for the simultaneous quantification of bilirubin and hemoglobin, and evaluate single-, two-, and multiwavelength methods. Although both species can be quantified from single- or two-wavelength absorption data, lipids or other absorbing or light-scattering components introduce systematic errors that can be substantially decreased by using first- or second-derivative spectra. Multi-wavelength data-processing methods with derivative spectra permit quantification of components with overlapping spectra and decrease the random error usually associated with derivative methods. A typical least-squares equation for quantifying bilirubin in the presence of hemoglobin and bovine serum albumin from multi-wavelength second-derivative data is y(computed) = 0.999x(prepared) + 0.00 mg/L.

Bilirubin↗
PubMed1985

Preparation of antibodies against the fourth complement component (C4) and development of a direct electroimmunoassay for quantification of C4d.

The specificity of several preparations of antihuman C4 antibodies were examined by crossed immunoelectrophoresis. Two antibody preparations with anti-C4c and anti-"total" C4 reactivity respectively were prepared by immunoadsorption procedures and defined by comparison with reference antibodies of known specificity. These two antibody preparations were used in the development of a rocket immunoelectrophoresis with an intermediate gel for specific and direct quantification of C4d. This method permits the selective quantification of activation of the classical complement pathway as opposed to the alternative pathway activation.

Antibodies↗
PubMed1985

Quantification of pulsatile flow during cardiopulmonary bypass to permit direct comparison of the effectiveness of various types of "pulsatile" and "nonpulsatile" flow.

The relative merits of adding a "pulsatile" component to flow during cardiopulmonary bypass (CPB) has long generated controversy, the resolution of which has been hampered by lack of quantification of the "pulsatility" delivered by different devices. The present experimental series had two goals: to quantify the "pulsatility" of blood flow during CPB in terms of pulse rate and pulsatility index (PI) and to examine which aspects of a "pulsed flow" provide clinical benefits. A flow waveform can be expressed in terms of its baseline rate and its PI, the sum of the square of its harmonics components divided by the square of the mean flow. We used PI to quantify the pulsatility of blood flow in the descending thoracic aorta and used changes in the serum lactate level as an indication of end organ flow. In one experimental series seven adult mongrel dogs were placed on roller pump CPB at a constant flow of 100 ml/kg/min. After a 20-minute stabilization period a roller pump wave and three different pulse shapes (generated by a computer-controlled hydraulic pump) were evaluated for 15 minutes each. The pulse wave shapes were graded, with C being the sharpest and A the least sharp. In a second series six other dogs were placed on CPB and were subjected to roller pump perfusion and three pulse waves of identical shape but at different rates. The results indicated that a combination of a minimum PI of 1.88 and a minimum rate of 80 bpm were necessary to significantly reduce lactate production as compared with roller pump perfusion. Thus the same mean flow can have very different physiologic effects depending on how it is delivered. This quantification method permits direct comparison of different "pulsatile waveforms" and provides a means for identification of optimal pulsatile flow.

Animals↗
PubMed1977

[Left ventricular contraction reserve in coronary heart disease. Evaluation, quantification and prognostic value (author's transl)].

Regional and overall left ventricular contraction reserve was studied in 14 patients with coronary heart disease, in 5 healthy subjects and in 4 patients before and after aorto-coronary bypass surgery. Quantification of overall contraction was based on ventricular volumes and ejection fraction. Regional contraction reserve was calculated with the hemiaxis method and a ventricular score. Contraction reserve under nitroglycerin and in postextrasystolic beats was compared. For routine quantification of contraction reserve the ventricular score is recommended. For research purposes the hemiaxis method is to be preferred. Postextrasystolic beats are better suited for analysis of contraction reserve than are angiograms following administration of nitroglycerin. This is due to the minor expense of the procedure, furthermore, postextrasystolic beats allow better differentiation between contracting and non-contracting areas. Left ventricular contraction reserve is larger in patients with coronary heart disease, angina pectoris and ischemic reactions in the exercise ECG than in control patients. These findings are based on overall and on regional volume parameters. A quantitatively greater improvement in contraction could be provoked in the anterior wall than in the posterior wall. Regional contraction improved significantly in most cases either in the anterior wall or in the posterior wall; rarely it improved simultaneously in both left ventricular regions. In a few cases contraction deteriorated in one area with a simultaneous improvement in the opposite area. Overall and regional ventricular function, as assessed preoperatively by contraction reserve determinations could not be completely regained in normal beats after successful bypass surgery. Differences in the regional contraction reserve seemed to be mainly due to varying degrees of ischemia and scarring.

Angina Pectoris↗
PubMed1979

Quantification of tetanus antitoxin in human sera. II. Comparison of counter-immunoelectrophoresis and passive haemagglutination with toxin neutralization in mice.

We described recently an improved counter-immunoelectrophoretic method for quantification of tetanus antitoxin. The toxin neutralization test in mice is considered to correlate well with protection in humans. In the present study, the correlation coefficient between the two methods was 0.89. Sera containing more than 7.0 I.U./ml could be quantified directly by counter-immunoelectrophoresis, while sera containing less tetanus antitoxin had to be concentrated prior to quantification. The passive haemagglutination test was also compared with the toxin neutralization test in mice. The correlation coefficient between the two methods was 0.76.

Antibodies, Bacterial↗