Critical evaluation of ASO RQ-PCR for minimal residual disease evaluation in multiple myeloma. A comparative analysis with flow cytometry.

We have analyzed the applicability, sensitivity and prognostic value of allele-specific oligonucleotide real-time quantitative PCR (ASO RQ-PCR) as a method for minimal residual disease (MRD) assessment in patients with multiple myeloma (MM), comparing the results with those of multiparameter flow cytometry (MFC). A total of 170 patients enrolled in three consecutive Spanish trials achieving at least partial response after treatment were included. Lack of clonality detection (n=31), unsuccessful sequencing (n=17) and suboptimal ASO performance (n=51) limited the applicability of PCR to 42% of cases. MRD was finally investigated in 103 patients (including 32 previously studied) with persistent disease identified by PCR and MFC in 54% and 46% of cases, respectively. A significant correlation in MRD quantitation by both the techniques was noted (r=0.881, P<0.001), being reflective of treatment intensity. Patients with <10(-4) residual tumor cells showed longer progression-free survival (PFS) compared with the rest (not reached (NR) vs 31 months, P=0.002), with similar results observed with MFC. Among complete responders (n=62), PCR discriminated two risk groups with different PFS (49 vs 26 months, P=0.001) and overall survival (NR vs 60 months, P=0.008). Thus, although less applicable than MFC, ASO RQ-PCR is a powerful technique to assess treatment efficacy and risk stratification in MM.

Bent oligonucleotide duplexes as HMGB1 inhibitors: a comparative study.

In this work we explore the ability of a chimeric LNA/DNA bent duplex, in which the kink is induced by 2 unpaired adenines in the middle of one strand, to bind HMGB1, a protein involved in many inflammatory processes. The LNA/DNA duplex was compared with the corresponding full DNA and PNA/DNA chimera duplexes from a thermodynamic and spectroscopic point of view.

Short-term results of hydroxyapatite-coated primary total hip arthroplasty.

One hundred consecutive patients who had Howmedica ABG total hip replacements, a system in which the femoral stem and the acetabular component are hydroxyapatite coated, during the period from September 1989 to January 1991 were studied prospectively. Clinical assessment using the d'Aubigné score showed that 96 patients had an excellent score at a minimum of 2 years from the operation. Radiographic analysis, based on DeLee and Charnley criteria for the acetabular cup and on Gruen criteria for the femoral stem, showed equally good results. There was good initial stability of the cup and the metaphyseal portion of the stem, with a secondary increase of load transmission in Zones 2 and 6 with cortical and cancellous thickening.

Thigh pain in cementless hip replacement. Clinical and radiographic correlations.

The authors analyse a series of 35 Rippen System cementless hip joint prostheses implanted in 32 patients from May 1987 to September 1988. Certain radiographic parameters were studied in an attempt to find a correlation with the clinical results. Special attention was paid to the high incidence of thigh pain, attempting to identify the cause through radiographic study of the bone-implant interface. Even when analyzed using Kappa statistics, the correlation between the clinical and radiographic findings was purely incidental. In agreement with the literature, the authors identify some elements which should be investigated further such as primary temporary fixation of the stem, reduction of micromotion, and biocompatibility of the materials.

Quality assurance for steroid receptor assay in human breast cancer: six years experience of the Italian Committee.

Since 1979 the quality control design proposed by the Italian ad hoc Committee has evaluated several lyophilized preparations with scalar receptor content; this permits the identification by linear regression analysis of systematic and non systematic errors. At present 41 laboratories from most of the national regions have joined the Italian Committee. The overall results of five years application of quality assurance in Italy show that there was a different pattern of imprecision with satisfactory indexes for intralaboratory performances but major variations in interlaboratory controls. There was also a remarkable difference of variability indices between the so-called "expert" and "new" laboratories; this problem can be reduced with practical seminars for new centers. On the basis of the results and experience achieved the Committee is starting another program of quality assurance for different new methodologies to provide guidelines for international working reference standards.

Quality control for estrogen and progesterone receptor assay in human breast cancer: the influence of computation methods on intra and interlaboratory variability.

The importance of evaluating receptors for estrogen and progestin in human breast cancer has been pointed out by many authors. In the absence of a reference standard, receptor assays must be controlled by intra and interlaboratory quality control programs. Much interlaboratory variability exists due to non-uniform analytical protocols, non-uniform ligands, intrinsic errors and also errors in computation methods. The goals of our Italian Quality Control Program on Multicenter Trials are to standardize the analytical procedures and computation methods. Twenty Italian laboratories participated in the Quality Control Program. Each specimen was assayed for steroid receptor content according to the standardized dextran-coated-charcoal method. Data were subjected to computerized analyses by 5 different methods of calculation (Scatchard plot, direct plot, Lineweaver-Burk method, Brunauer-Emmet-Teller analysis, single-point approach). The results were than evaluated to identify intra- and inter-assay variation coefficients and to define other statistical parameters. The authors suggest different calculation methods depending on the specific experimental and/or physiopathological conditions.

Some thoughts on a possible regulatory approach at EEC level on the classification and labeling of dangerous preparations.

At the present time no European directives on classification, packaging, and labeling exist which cover all dangerous preparations of chemicals. To develop such a directive, the Commission of the European Economic Community services, at the request of and in close collaboration with experts of the member states, has conceived a method for evaluating the toxicity of mixtures of chemicals. This method consists of (a) the characterization of each constituent by means of an index and (b) the classification of preparations for each route of administration on the basis of their toxicity. The index is a figure representing the degree of dilution needed to render the substance not dangerous in the sense of the EEC Directives on the classification of dangerous substances; the highest index among those obtained for acute and chronic toxicity is taken to characterize the substances. An indication of toxicity is obtained by applying the simple equation sigma (P X I), where P is the percentage and I is the index of each constituent. The most stringent classification among those obtained for the three routes of administration is taken for the final classification of the preparation on the basis of its acute and chronic toxicity. Other toxicological effects such as irritation, corrosion, sensitization, mutagenesis, teratogenesis, and carcinogenesis are not considered.

Cyclic adenosine-3':5'-monophosphate binding proteins in human mammary tumor cytosol and their relation to estrogen and progesterone receptors. A preliminary study.

A method for determining cAMP-binding activity in human mammary tumor cytosol is described and the results of routine assay on 57 tumor samples are presented in relation to the estrogen and progesterone receptor levels. Results show that the values of each single parameter are very largely dispersed. The estrogen receptor/cAMP-binding protein ratio distributes in a very interesting way, in view of a retrospective clinical trial now in progress.

[Protein assay for cellular receptors of steroids: a critical study of the technic with Coomassie-blue]. / Dosaggio delle proteine nella determinazione dei recettori cellulari degli steroidi: studio critico della tecnica con Coomassie-blue.

The Coomassie-Blue method for protein determination is the EORTC uniformed technique for steroid receptor assay in tumor tissues. Many quality control trials have shown unacceptable interlaboratory variation coefficients for protein determination in steroid receptor assay. The objective of this study is to check the critical parameters of the method. The authors propose some suggestions on stability of dye-protein complex, ionic strength and temperature influence to improve the accuracy of the method.

Relationship between mutagenic effect and toxic effect in the Ames test.

This study concerns the relationship between spontaneous revertants and number of bacterial cells plated in the Ames test. These two parameters do not appear to bear a direct relationship: marked variations in cell input are attended by negligible variations in spontaneous revertants. However, a relationship, described by a quadratic equation that approximates a hyperbole, exists between the spontaneous revertants and the number of total cellular divisions permitted by the histidine concentration in the medium. Furthermore a direct linear relationship has been observed between cell input and diameter of the plate background microcolonies. The problem of the toxic effect in the Ames test performed with drugs or substances having high bactericidal activity is discussed.

Results of the Italian interlaboratory quality control program for estradiol receptor assay.

This article presents results of the first Italian quality control program for determining the estradiol receptor on lypophilized guinea pig and calf uteri. Despite considerable variability in quantitative terms, the results concur in ability to define samples as positive or negative for receptor content. One of the parameters that most strongly influences accuracy of determination of receptor concentration is protein assay. The evaluation of several lyophilized preparations at scalar concentrations permitted identification, by linear regression, for each laboratory of the systematic and non-systematic variables. More comparable results will be forthcoming when a standardized methodology program has been fully adopted.

Metabolism of fentiazac.

The main metabolite of 2-phenyl-4-p-chlorophenylthiazol-5-ylacetic acid (fentiazac) is represented by a p-hydroxylated compound which is formed rapidly and that, still 72 later, can be detected in the general circulation. The p-hydroxylated metabolite is much less toxic than the original molecule from which it derives, being still active from an anti-inflammatory standpoint (its activity being equal to 70--75% of that of fentiazac). The metabolite, which possesses a therapeutic index much higher than that of fentiazac, represents quite an important step in the detoxication processes of the drug and enhances the therapeutic activity of the drug itself.