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G Merlini

Publications and source records attributed to G Merlini.

At least 19 recordsLinked to original sources
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↗
PubMed1991

Amino acid sequence of k Sci, the Bence Jones protein isolated from a patient with light chain deposition disease.

Light chain Sci was isolated from the urine of a patient affected by light chain deposition disease with an apparent exclusive localization to the kidney. Sci protein is an intact light chain: it consists of 214 amino acid residues and has an Mr of 23.65. Its complete primary structure has been determined by sequence analysis of the corresponding tryptic peptides and by partially sequencing the intact protein. Sequence comparison shows that Sci protein is strictly related to the light chains of kIIIa family (88% structural identity) which are usually expressed in autoimmune rheumatoid syndromes. Computer graphics model suggests a perturbation in k Sci three-dimensional structure due to the unusual replacement of residues 53 and 77.

Aged↗
PubMed1991

Amino acid sequence of the FV region of a human monoclonal IgM (NOV) with specificity for the capsular polysaccharide of the group B meningococcus and of Escherichia coli K1, which cross-reacts with polynucleotides and with denatured DNA.

The complete amino acid sequences of the VH and VL regions of a biologically significant Ig, IgMNOV, were determined. IgMNOV is reactive with the capsular polysaccharide of the group B meningococcus and of Escherichia coli K1. As reported earlier, it cross-reacts completely with polynucleotides poly(A) and poly(I) and to a lesser extent with denatured DNA and protects newborn rats against infection with E. coli K1, and is equal in potency to the standard horse anti-group B meningococcal serum. The reduced and alkylated chains were sequenced directly, identifying the L chain as lambda-subgroup II and the mu-H chain as subgroup III. The complete sequence of the VL region was determined by sequencing peptides generated by cleavage with Staphylococcus aureus protease, chymotrypsin, and trypsin. The H chain was cleaved with cyanogen bromide followed by enzymatic cleavages to obtain a large part of the VH region sequence. The structure was completed by sequencing tryptic peptides of the Fab fragment and by mass-spectrometric analysis.

Amino Acid Sequence↗
PubMed1991

Efficacy of peptide bound m-L-sarcolysin (peptichemio) on melphalan resistant human myeloma cells in vitro.

Peptichemio (PTC) is a mixture of six synthetic oligopeptides, each containing the alkylating agent m-di(2-chloroethyl)amino-phenylalanine. Freshly obtained myeloma cell infiltrated human bone marrow specimens were in parallel exposed to melphalan and PTC. The cytotoxic effect of the drugs on the myeloma cells of each specimen was measured by the differential staining culture method (DISC). PTC displayed higher cytotoxicity to the myeloma cells as compared to melphalan in all 12 cases analysed. The increase of the cytotoxic effect of PTC compared to melphalan varied between different cases. In melphalan resistant cases the cytotoxic effect of PTC as compared to melphalan was clearly significant (P = 0.001).

Aged↗
PubMed1991

A plea to overcome the concept of "staging" and related inadequacy in multiple myeloma.

From a retrospective multivariate study on 107 multiple myeloma (MM) patients, serum beta 2-microglobulin (beta 2M) proved to be the best prognostic discriminator, better than each of the currently used staging systems (Durie and Salmon's [DS], Merlini, Waldenström and Jayakar's [MWJ] and the British Medical Research Council's [BMRC]). The predictive ability of each staging system is better improved by combining consideration of beta 2 M as a continuous rather than a binary variable (even at its best prognostic cut-off). The combination of BMRC with beta 2 M demonstrated the highest prognostic value, followed by those involving DS or MWJ. Ease and measurability of clinical parameters at diagnosis, parametric type of statistical model assumed for description of survival, and supply of direct estimate of expected survival are the characteristics of the MWJ system that suggest it is best able to integrate beta 2 M correctly in a prognostic index. The basic concepts and the clinical use of the available staging systems for MM are criticized along the following lines: a) the need to include new and homogeneously weighted parameters in future prognostic systems -b) the lack of direct correspondence between treatment requirements (according to stage) and available therapeutic resources -c) evidence of the rough stratification of the actual survival expectancy, as permitted by the current staging systems. A direct, and as accurate as possible estimate of prognosis--based on easy and measurable parameters evaluable at diagnosis--should replace the current classification of patients according to stages. This estimate should mark the clinical evaluation at diagnosis, should flexibly indicate treatment even according to different protocols or centers, and should allow very accurate statistical corrections for different survival expectancy at diagnosis when evaluating different treatments in clinical trials.

Adult↗
PubMed1990

The second riboflavin-binding myeloma IgG lambdaDOT. I. Biochemical and functional characterization.

A human monoclonal immunoglobulin, IgGDOT, with flavin-binding capacity has been obtained from an elderly woman with multiple myeloma who developed yellow skin and yellow hair. The case presented a remarkable similarity with that previously reported by Farhangi and Osserman [N. Engl. J. Med. 294, 177-183 (1976)]. Purified IgGDOT was bright yellow and the ligand was identified as riboflavin and its oxidation products by thin layer chromatography, proton nuclear magnetic resonance and mass spectroscopy. Competitive binding studies with different haptens demonstrated highest affinity for riboflavin, followed by flavin mononucleotide and flavin adenine dinucleotide; no significant binding was detected for several other non-flavin compounds tested. The hapten was associated with the protein in vivo, as well as with the purified antibody. Removal of the already bound riboflavin from the combining site was associated with irreversible denaturation of the monoclonal protein. By the fluorescence quenching technique it was determined that there were 0.68 available combining sites for riboflavin molecule in IgGDOT with a binding constant of 8.5 x 10(8)/M, while FabDOT presented 0.27 available combining sites with a binding constant of 5.1 x 10(8)/M. The fact that 1.2 and 0.81 mol riboflavin/mol protein were already bound to IgGDOT and FabDOT, respectively, is consistent with the usual hapten/antibody stoichiometry. The heavy chain subclass of IgGDOT was identified as gamma 2, as in the previously reported case of riboflavin-binding protein IgGGAR. However, the lambda chain subclass was different and no idiotype cross-reactivity was found.

Aged↗
PubMed1990

Relevance of class, molecular weight and isoelectric point in predicting human light chain amyloidogenicity.

The ability to predict the amyloidogenicity of certain light chains may facilitate an earlier diagnosis of AL amyloidosis and, possibly, lead to more effective treatment. Using current methods, available in clinical chemistry laboratories, we assessed the class, the relative molecular mass (Mr) and the isoelectric point of urinary monoclonal light chains from 35 patients with AL amyloidosis (A+) and 51 without amyloidosis (A-). The light chain class (LCC) was lambda in 77% and 45% of A+ and A- patients, respectively. Light chain fragments (LCF) with low Mr (12-18 x 10(3) were detected in the urine of 30/35 A+ patients and in 15/51 A- ones. The mean (SD) isoelectric point (pI) of A+ light chains was 4.8 (1.1) while in A- patients it was 6.2 (1.6). Univariate analysis showed significant differences between the two groups for the three parameters. Discriminant analysis gave a function which allowed a correct allocation of 81% of the cases between the two groups.

Amyloidosis↗
PubMed1989

Structural characterization of kappa II Inc, a new amyloid immunoglobulin.

Light chain Inc, obtained from a patient with amyloid arthropathy, has an Mr of 23,550 and consists of 219 amino acid residues. The complete primary structure of its variable domain has been determined by sequence analysis of the corresponding tryptic peptides, aligned by fragments derived from cyanogen bromide digestion, and by partially sequencing the intact protein. Although closely related to protein of the V kappa II subgroup, light chain Inc differs from its counterpart by the replacement of some invariant residues in its variable domain. By comparing its sequence with that of the nonamyloid kappa II Nim, a different distribution of some polar and apolar amino acid residues through the molecule is evidenced. A computer graphic analysis shows that some of the replaced amino acid residues cannot be readily accommodated in the known three-dimensional structure of the immunoglobulin light chains.

Amino Acid Sequence↗
PubMed1989

Study of three patients with monoclonal gammopathies and 'lupus-like' anticoagulants.

In three patients with monoclonal gammopathies: a case of multiple myeloma, a case of monoclonal gammopathy of uncertain significance (MGUS) and a case of monoclonal gammopathy associated with lymphocytic lymphoma, we found the presence of a circulating lupus-like anticoagulant. Coagulative studies showed that the paraproteins: an IgG3k, an IgG1k and an IgMlambda, were responsible for the anticoagulant activity by interacting with the thromboplastin phospholipids. Using isoelectrofocusing we demonstrated that the three monoclonal immunoglobulins had a strong basic charge which may have contributed to determining their interaction with the acidic thromboplastin phospholipids. The binding of various phospholipids to the monoclonal proteins was assessed by the fluorescence quenching method which showed heterogeneous specificity. In order to establish whether the electrical charge is also relevant in cases with polyclonal lupus anticoagulant, the polyclonal immunoglobulins were fractionated according to their charge. The strongest inhibitor activity was found in the most basic immunoglobulins. Monoclonal lupus-like anticoagulants represent useful tools for investigating the heterogeneous world of polyclonal lupus-like anticoagulants.

Aged↗
PubMed1989

The Merlini, Waldenström, Jayakar staging system revisited.

At present, none of the routinely used staging systems is entirely satisfactory, since all of them require some reconsideration to account for the most recent prognostic factors. Among these, serum beta-2 microglobulin (S-beta-2M) has proved to be a powerful prognostic test assessable in most centers. In order to improve the Merlini, Waldenström, Jayakar (MWJ) staging system, we have determined the prognostic significance of several factors in an independent population of 345 retrospective myeloma patients seen at our institution from 1973 to 1988. The Cox regression hazards method showed that S-Creatinine, S-Albumin levels and percentage of bone marrow plasma cells accounted for 94% of total chi 2 achieved with all eight variables (including also: paraprotein index, S-Calcium, S-M-component, bone lesions and hemoglobin). The same analysis, applied to patients in whom S-beta-2M was available at presentation, selected S-beta-2M, S-Creatinine and percentage of bone marrow plasma cells (accounting for 92% of total chi 2), followed by platelet count, S-Albumin and S-M-component. The best discriminatory level of S-beta-2M was found to be 4 mg/l. However, the prognostic power of S-beta-2M when used with binary values was remarkably reduced with respect to its application as a continuous variable. In patients with MWJ stage 1 and 2 disease, S-beta-2M had an independent prognostic significance. Grouping stage I and II patients with S-beta-2M less than or more than 4 mg/l presented a median survival of 70 and 40 months, respectively. In stage 3 patients S-beta-2M did not contribute additional prognostic information.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Treatment of painful bone lesions and hypercalcemia.

The control of myeloma bone disease has been an important therapeutic problem. Bisphosphonates are potentially active for the control of myeloma bone resorption. Although several studies proved the efficacy of short-term bisphosphonate treatment in inhibiting myeloma bone destruction, data on the long-term efficacy are scanty. We present the results of a prospective pilot study for the evaluation of long-term parenteral administration of dichloromethylene bisphosphonate (Clodronate) in 30 patients with active myeloma bone disease. Patients were treated with a mean of 4 courses (range 2-8) of Clodronate: 300 mg/d i.v. for 7 days followed by 100 mg/d i.m. for 10 d, administered at a mean interval of 4 months. The median follow-up was 24 months (range 8-36). Clodronate reduced bone pain rapidly and significantly, and reduced the mean values of the biochemical indices of bone resorption to within normal limits. The occurrence of skeletal morbidity in patients treated with Clodronate was compared with that observed in the control group of myeloma patients treated with chemotherapy only: Clodronate provided a significant (p less than 0.001) reduction in severe bone pain as well as in the incidence of new osteolytic lesions and pathological fractures. The results of this prospective pilot trial indicate that supportive long-term treatment with parenteral Clodronate can contribute significantly to controlling the progression of myeloma bone disease.

Bone Diseases↗
PubMed1987

Serum thymidine kinase and beta-2 microglobulin in monoclonal gammopathies.

We evaluated the serum thymidine kinase (TK) and beta-2 microglobulin (beta-2) levels of 22 patients with monoclonal gammopathy of undetermined significance (MGUS) and of 29 patients with multiple myeloma (MM). Both parameters were significantly lower in MGUS than in MM patients and in early (stage I + II) than in advanced (stage III) MM. TK was also lower in MGUS than in stage I MM (p less than 0.025). A seven-fold increase of TK level was documented in one patient who developed a full blown picture of MM 6 years after a diagnosis of MGUS. In 3 patients with stage III MM, a sharp decrease in TK (40-77%) and in beta-2 (29-53%) levels at remission was evident with respect to the levels measured at diagnosis. Patients with high levels of TK or beta-2 had a shorter survival than those with low levels; however, this was statistically significant only for beta-2 levels (p less than 0.02). Serum TK as well as beta-2 levels appear to be of clinical value in monoclonal gammopathies and related to the course of the disease.

Adult↗
PubMed1987

A sulfhydryl-rich IgM protein with multiple serological specificities.

A monoclonal IgM lambda protein from a patient (E.T.) suffering from a lymphocytic lymphoma agglutinated Salmonella typhi bacteria and uncoated acryl particles. The antigenic determinant on Salmonella typhi bacteria was found to be 0-12 (alpha-D-Galp-(1-2)-alpha-D-Manp) while the structure on acryl particles recognized by IgM ET has not been defined. Both binding sites for bacteria and acryl particle determinants are localized on the same IgM molecule. The uncommon affinity of this IgM protein for some divalent heavy metal ions led to the finding of an unusually high content of sulfhydryl groups in the Fab portion of the molecule.

Acrylates↗
PubMed1987

Effects of a new aminodiphosphonate (aminohydroxybutylidene diphosphonate) in patients with osteolytic lesions from metastases and myelomatosis. Comparison with dichloromethylene diphosphonate.

We have compared in an open trial the clinical and biochemical effects of a new aminodiphosphonate, aminohydroxybutylidene diphosphonate, with those of dichloromethylene diphosphonate, which has been proved effective. The patients presented extensive and symptomatic bone involvement from multiple myeloma, breast cancer, and other metastatic tumors. The treatment consisted of aminohydroxybutylidene diphosphonate, 2.5 mg/d intravenously for five days, or dichloromethylene diphosphonate, 300 mg/d intravenously for seven days, followed by 100 mg/d intramuscularly for ten days. Twelve patients treated with aminohydroxybutylidene diphosphonate and 16 patients treated with dichloromethylene diphosphonate were assessable and were followed up for one to six months. Therapy with aminohydroxybutylidene diphosphonate showed a quicker action in reducing bone pain and reduced significantly more the serum calcium level than did therapy with dichloromethylene diphosphonate. Aminohydroxybutylidene diphosphonate therapy also affected urinary calcium levels and hydroxyproline excretion more markedly than did dichloromethylene diphosphonate, although the differences are not statistically significant. However, the biochemical indexes rebounded more quickly in patients treated with aminohydroxybutylidene diphosphonate, indicating that the loading amount (only 12.5 mg) used in this preliminary study is insufficient to sustain a prolonged effect. The effectiveness and lack of side effects render aminohydroxybutylidene diphosphonate an attractive treatment for malignant bone resorption.

Adult↗