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Biomedical subjects

G J Buffone

Publications and source records attributed to G J Buffone.

At least 73 records · Page 4Linked to original sources
PubMed1983

Isoelectric focusing in agarose: classification of genetic variants of alpha 1-antitrypsin.

Polyacrylamide has been the matrix of choice for isoelectric focusing owing to the virtual absence of electroendosmosis in this medium. Certain inherent limitations associated with polyacrylamide have prompted some investigators to use low-electroendosmosis agarose for isoelectric focusing, but with limited success thus far. We have developed a method for isoelectric focusing in agarose for the classification of alpha 1-antitrypsin variants. Sera are applied directly to agarose gels containing a pH 4-5 ampholyte mixture, focused for less than 1 h, and directly immunofixed. Resolution of major bands is equivalent to polyacrylamide, and Pi M subtypes can be distinguished without the use of a separator. This application demonstrates the high resolution of isoelectric focusing in agarose, a more practical and convenient matrix than polyacrylamide.

Acrylic Resins↗
PubMed1983

An immunoradiometric assay for erythrocyte complement (C3b) receptor activity applied to a pediatric population with connective tissue disease.

The number of receptors for complement component C3b per erythrocyte reportedly is decreased in over half of adults with systemic lupus erythematosus. We have devised an immunoradiometric assay for C3b receptor (CR1) on erythrocytes, with which one can assess CR1 saturation due to in vivo binding of immune complexes or activated complement fragments (C3b). Using this assay, we examined binding by CR1 in normal adults and newborns, in lupus and juvenile rheumatoid arthritis patients, and in a population of patients with various general medical problems, including other connective tissue diseases. Binding by CR1 was decreased in eight of 15 SLE patients, four of 25 juvenile rheumatoid arthritis patients, and one of 14 patients with other diseases. We found no significant correlation between CR1 binding and either C1q binding, antinuclear antibody titer, results for complement C3 and C4, or the presence of renal disease. Using this assay, we were also able to show that the observed reduction in CR1 binding was not ascribable to prior saturation of CR1 or to blocking antibody against CR1. The assay is precise and easy enough for routine application.

Adult↗
PubMed1981

Protein clearances and selectivity determinations in childhood nephrosis: a reappraisal.

To critically evaluate the clinical utility of determining specific proteins in patients with extensive proteinuria, we used immunonephelometric methods to measure albumin, transferrin, IgG, and alpha 2-macroglobulin in serum and in 24-h urine specimens from 37 children with idiopathic nephrotic syndrome. Renal biopsy demonstrated minimal change disease (I) in 15, focal glomerulosclerosis (II) in 15, and membranoproliferative glomerulonephritis (III) in seven patients. A three-group nonparametric rank test and three-group discriminant function analysis of the protein excretion and clearances of the four proteins we measured revealed significant differences in the excretion of IgG and the clearance of alpha 2-macroglobulin among the three groups of patients (p less than 0.05). Only patients with III had low serum complement C3 concentrations. Patients with I or II were best discriminated by differences in the excretion of transferrin and IgG, the clearance of alpha 2-macroglobulin, and the selectivity index (the clearance ratio of IgG/transferrin). These data indicate that measurement of specific urinary proteins and selectivity determinations may be helpful in predicting the type of histopathology and the prognosis of nephrotic children who have normal complement concentrations.

Adolescent↗
PubMed1980

Evaluation of an immobilized-enzyme analyzer for measuring galactose in serum.

Reportedly, galactose provides an alternative carbohydrate source and improved homeostatic regulation of glucose in the premature infant. Because of its potentially toxic effects, sensitive methods are needed for monitoring its concentration during therapy. We evaluated an immobilized galactose oxidase/hydrogen peroxide electrode system and a modified homogeneous enzymic method. Both methods are suitable for measuring galactose in a small sample and are comparably precise. The latter method gives superior analytical recoveries below 100 mg/L, but is linear in absorbance response to only 300 mg/L. We find the immobilized-enzyme method superior for monitoring treatment of neonates with galactose, because it requires only a few minutes and 25 microL of serum, and the analytical procedure is simpler.

Enzymes, Immobilized↗
PubMed1979

Limitations of immunochemical measurement of ceruloplasmin.

We describe a quantitative immunochemical method for the nephelometric measurement of ceruloplasmin. Results are compared with those from a radial immunodiffusion technique. We examine factors affecting the results, such as antiserum source and calibrators, and list reference limits for a pediatric population.

Age Factors↗
PubMed1979

Simultaneous use of rapidly absorbed and sustained release theophylline preparations in children.

Each of 12 asthmatic children received a single dose of Theolair, 5 mg/kg, a single dose of Theolair SR, 10 mg/Kg, or both Theolair, 3 mg/Kg and Theolair SR, 10 mg/Kg on three separate days. Administration of both preparations together was followed by serum theophylline concentrations significantly higher than Theolair alone at 2 or 12 hours and significantly higher than Theolair SR alone at every time except six hours. This method of theophylline administration may be useful in the asthmatic patient who requires medication only intermittently.

Absorption↗
PubMed1978

Chemical and immunochemical measurement of total iron-binding capacity compared.

Radiometric, colorimetric, and two immunochemical methods for measuring total iron-binding capacity are compared. We evaluated the procedures on the basis of precision, applicability to a pediatric population, and accuracy as assessed by analytical recovery of purified transferrin. The immunoephelometric assay for transferrin provides significant advantages over the other methods examined.

Adolescent↗
PubMed1977

Effect of analytical factors on immunochemical reference limits for complement component C3 in serum of a reference pediatric population.

We evaluated analytical factors such as antibody specificity, standard materials, and methodology for the measurement of C3. Mancini-type radial immunodiffusion and immunonephelometry were shown to give comparable data if variables other than procedural variables are eliminated. The most significant analytical factors affecting the measurement were antiserum specificity and source of standard material.

Adolescent↗
PubMed1977

New approach to evaluation of proteinuric states.

We evaluated the use of immunonephelometric methods for measuring specific urinary proteins. Using a nephelometer to detect light scattering (angle, 31 degrees), we measured some proteins immunonephelometrically in serum and aliquots of 24-h urines from 50 apparently healthy children, ages 2-17 years. The mean urinary excretion rate (mg/24h) and the range of values was: for albumin 5.5 (range, 0-13.3), for transferrin 0.5 (0-1.9, for IgG 3.3 0-12), and for alpha 2-macroglobulin 0.6 (0-2.3). Direct comparison of the values for pathological urines with those for a reference population may offer more meaningful information concerning the integrity of the glomerular basement membrane than is provided by protein selectivity indices, and measuring a plasma protein such as albumin in urine may better define pathological proteinuria.

Adolescent↗
PubMed1976

Evaluation of a new blood-collecting device ("microtainer") that is suited for pediatric use.

We evaluated the prototype of a "Microtainer" (800-mul) tube (Becton-Dickinson Co., Rutherford, N.J. 07070), In which a semi-solid silicone material is used to separate serum from erythrocytes on centrifugation. We compared results for 18 serum analytes with those obtained for specimens collected by the "dripping" method of capillary blood collection. The serum was examined microscopically for platelets and leukocytes from both normal and leukemic specimens. The cellular elements were all contained in the erythrocyte layer. Hemolysis was negligible. Means for paired samples did not differ significantly, except for Na+, for which the difference was not clinically significant. Values for potassium and lactate dehydrogenase were unchanged 24 h after collection, even though the serum was left in the collecting device.

Blood Chemical Analysis↗
PubMed1975

Evaluation of kinetic light scattering as an approach to the measurement of specific proteins with the centrifugal analyzer. I. Methodology.

A laser-modified centrifugal analyzer was used to develop kinetic light scattering methods for the measurement of human immunoglobulins IgG, IgA, and IgM. Comparison of equilibrium light scattering methods with kinetic procedures for IgG and IgA demonstrate equivalent precision and relative accuracy. However, quantitative results obtained by equilibrium and kinetics methods for IgM were found to differ significantly. Recovery studies performed with purified IgM have shown that both methods can yield quantitative results in the normal range. Our observations demonstrate that the technique offers a viable and in some respects a superior alternative to other methods currently used in the clinical laboratory.

Autoanalysis↗
PubMed1975

Evaluation of kinetic light scattering as an approach to the measurement of specific proteins with the centrifugal analyzer. II. Theoretical considerations.

Development of centrifugal analyzers capable of making light-scattering measurements has prompted the investigation of the application of this type of instrumentation to the measurement of specific proteins. Investigation of antigen/antibody complex dimension and the kinetics of the IgG/anti-IgG reaction as followed by light scattering are examined in relation to improved analytical methodology. The effect of nonspecific protein on the reaction rate has been investigated for IgM, and data are presented that provide insight into the mechanism of the effect of periodic mixing.

Antigen-Antibody Reactions↗
PubMedDate not supplied

Optimization of EMIT reagent system using a COBAS-BIO centrifugal analyzer.

An optimized method for application of the EMIT reagent system to a COBAS-BIO centrifugal analyzer was developed to minimize reagent consumption while maintaining good precision and accuracy. Forty-one serum samples, previously analyzed for theophylline by HPLC, were assayed using the modified protocol on the COBAS-BIO centrifugal analyzer. Regression analysis of the results obtained from both methods yielded the following equation: y = 1.10x + 0.01, r = 0.964 (x = HPLC, y = COBAS-BIO centrifugal analyzer, EMIT). The COBAS-BIO centrifugal analyzer and EMIT methodology provided an efficient, inexpensive, and relatively effortless approach to drug monitoring in the routine clinical laboratory.

Anticonvulsants↗