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Biomedical subjects

M R Bergami

Publications and source records attributed to M R Bergami.

7 recordsLinked to original sources
PubMed1993

High-sensitivity electrophoretic method for the detection of Bence Jones protein and for the study of proteinuria in unconcentrated urines.

The study of proteinuria, and especially the search for Bence Jones proteins (BJP), has almost always required urine concentration. We evaluated a high-sensitivity electrophoretic method using unconcentrated urine based on colloidal gold staining. The sensitivity for the detection of BJP is further enhanced by immunofixation. Sensitivity to BJP is better than 1 mg/L and, apart from the alpha-1 microglobulin, all the proteins relevant to the classification of proteinuria can be visualized with a sensitivity of approximatively 3 mg/L.

Bence Jones Protein↗
PubMed1992

Occurrence of monoclonal components in general practice: clinical implications.

We report on the occurrence of monoclonal components observed in a provincial hospital in northern Italy from 1987 to 1990. The monoclonal components were detected by visual inspection of high-resolution acetate serum electrophoreses and typed by immunofixation. The percentage of monoclonal components increases steeply with age, and reaches a plateau of 7-8% in individuals over 55 years old. Besides the high percentage of monoclonal component, the other relevant finding of this study is that approximately 80% of monoclonal components are of low concentration (less than 5 g/l). Most of these subjects with small monoclonal component passed undetected in the previous studies on the prognostic significance of monoclonal gammapathy. These findings indicate the need for a revision of the current concepts on the biological and clinical significance of MC discovered by chance.

Adolescent↗
PubMed1992

Reference values for immunoglobulin kappa and lambda light chains and the kappa/lambda ratio in children's serum.

We analyzed 708 serum samples from healthy children and adolescents by immunonephelometry to obtain reference values for the immunoglobulin kappa (kappa) and lambda (lambda) light chains and for their ratio at a time of life when immunoglobulin synthesis is maturing and continually being stimulated. The lambda chain concentration that is to be maintained throughout the child's life is reached very early, just after 1 year, whereas the concentration of the kappa chains, which increases gradually, reflects the concentration of the immunoglobulins as a whole. These reference values may be useful for studying kappa and lambda chains in illnesses involving the immune system in children.

Adolescent↗
PubMed1991

Restricted electrophoretic heterogeneity of immunoglobulin light chains in urine: a cause for confusion with Bence Jones protein.

The detection of Bence Jones protein, an important part of the investigation of suspected myeloma, is most commonly done by agarose or cellulose nitrate electrophoresis followed by immunofixation. Bence Jones protein is recognized as single or multiple bands of one type of light chain. Unfortunately, improvements in sensitivity of these techniques (use of high-affinity antisera and higher resolution electrophoresis) frequently allow detection of multiple light chain bands in the urine of patients who do not have a B-cell dyscrasia. The bands are usually kappa, although they may be accompanied by lambda bands. This pattern may lead to the misdiagnosis of Bence Jones protein and oligoclonal light chain production in patients. Here we show that this pattern is produced by polyclonal light chains; it is present in the urine of all patients with a tubular proteinuria of any etiology and may be induced in healthy individuals by blocking their renal tubular protein reabsorption. Polyclonal light chains separate into monomers and dimers on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and into four major bands with many minor bands by isoelectric focusing. This difference in charge and possibly size results in the banding pattern seen on good-quality electrophoresis and immunofixation.

Aged↗
PubMed1991

Use of immunoglobulin heavy-chain and light-chain measurements in a multicenter trial to investigate monoclonal components: I. Detection.

We assessed the combined use of serum protein electrophoresis (SPE) and nephelometric measurement of immunoglobulin heavy- and light-chain components for detecting serum monoclonal immunoglobulins (monoclonal components, MC) in 4788 unselected samples from 4173 patients. MC were detected in 514 samples from 390 patients. In 356 these were detected by SPE; the other 34 had a normal SPE pattern but an abnormal kappa:lambda light-chain ratio (KLR). Only 208 of the 356 (58%) samples with bands by SPE had abnormal KLRs. Samples with MC concentrations greater than 5 g/L had a higher proportion of abnormal KLRs (75%) than those with concentrations less than 5 g/L (42%). The KLR was abnormal in 13% of samples in which no MC were visible by SPE or immunofixation electrophoresis (IFE). Compared with quantitative measurements of immunoglobulin heavy and light chains, high-quality SPE remains the method of choice for the detection of MC. Quantitative methods, however, are able to detect additional MC, especially those containing free light chains, and in the absence of SPE and IFE will detect about 75% of MC present at greater than 5 g/L.

Antibodies, Monoclonal↗
PubMed1991

Use of immunoglobulin heavy-chain and light-chain measurements in a multicenter trial to investigate monoclonal components: II. Classification by use of computer-based algorithms.

We describe a computer algorithm for classifying serum monoclonal proteins (MC) based on serum protein electrophoresis (SPE) and the automated measurement of kappa and lambda light chains and IgG, IgA, and IgM. We developed the algorithm by using a large database of unselected samples containing MC collected in a multicenter study. The performance of the algorithm was optimized by using iterative computational procedures and was tested on both the development database and on an independent set of MC-containing samples. With the development database, the algorithm correctly classified 50% and misassigned 2.5% of the MC. Where the MC were present in concentrations greater than 10 g/L, the rate of successful classification increased to 72% with 3% misclassification. When the algorithm was tested on a group of 101 MC-containing samples from an independent source, 67% were correctly classified and 8% misclassified, half of the latter being unusual IgD myelomas. We discuss the scope for the application of the algorithm in routine laboratory practice involving personal computer software.

Algorithms↗