Accuracy of mammography and echography versus clinical palpation in the assessment of response to primary chemotherapy in breast cancer patients with operable disease.

The response to primary chemotherapy is an important prognostic factor in patients with non metastatic breast cancer. In this study we compared the assessment of response performed by clinical palpation to that performed by echography and mammography in 141 out of 157 consecutive breast cancer patients (T2-4, N0-1, M0) submitted to primary chemotherapy. A low relationship was recorded between tumor size assessed clinically and that evaluated by either mammography: Spearman R = 0.38 or echography: R = 0.24, while a greater correlation was found between the tumor dimension obtained by the two imaging techniques (R = 0.62). According to the WHO criteria, the grade of response of breast cancer to primary chemotherapy, showed by mammography and echography, was less marked than the grade of response seen at clinical examination. Residual tumor size assessed clinically depicted a stronger correlation with pathological findings (R = 0.68) than the residual disease assessed by echography (R = 0.29) and mammography (R = 0.33). Post-chemotherapy histology evaluation revealed pathological complete response in three cases (2.1%). Two of these cases were judged as complete responders by clinical palpation but only one was recognized by mammography, and none by echography. Clinical response, but not the response obtained by the two imaging techniques, was a significant predictor for longer disease free survival (p = 0.04). To conclude, physical examination measurements remain the method of choice in evaluating preoperatively the disease response in trials of primary chemotherapy. Prediction of pathological outcome is not improved by echography and mammography.

Cysteine 144 is a key residue in the copper reduction by the beta-amyloid precursor protein.

The beta-amyloid precursor protein (beta-APP) contains a copper-binding site localized between amino acids 135 and 156 (beta-APP(135-156)). We have employed synthetic beta-APP peptides to characterize their capacities to reduce Cu(II) to Cu(I). Analogues of the wild-type beta-APP(135-156) peptide, containing specific amino acid substitutions, were used to establish which residues are specifically involved in the reduction of copper by beta-APP(135-156). We report here that beta-APP's copper-binding domain reduced Cu(II) to Cu(I). The single-mutant beta-APP(His147-->Ala) and the double-mutant beta-APP(His147-->Ala/His149-->Ala) showed a small decrease in copper reduction in relation to the wild-type peptide and the beta-APP(Cys144-->Ser) mutation abolished it, suggesting that Cys144 is the key amino acid in the oxidoreduction reaction. Our results confirm that soluble beta-APP is involved in the reduction of Cu(II) to Cu(I).

Spectrophotometric determination of selenium(IV) with 5,5-dimethyl-1,3-cyclohexanedione.

5,5-Dimethyl-1,3-cyclohexanedione (dimedone) reacts in acid aqueous solution with selenium(IV) to give a benzoxaselenol which has an absorption maximum at 313 nm with a molar absorptivity of 4.00 x 10(3) l.mole(-1).cm(-1). The compound is extractable into chloroform, to give a solution with an absorption maximum at 300 nm with a molar absorptivity of 3.77 x 10(3) l.mole(-1).cm(-1). The calibration graph is linear up to 30 ppm selenium, with a detection limit of 0.1 ppm in the final solutions. Of the various other ions tested, only iron(III) interferes at all concentrations but the addition of 1000 ppm fluoride will mask 50 ppm Fe(3+). The method has good reproducibility, with a relative standard deviation of 1.0% for pure solutions. The method has been applied to the analysis of fire-refined copper.

Spectrophotometric determination of trace amounts of selenium with 4,5,6-triaminopyrimidine.

4,5,6-Triaminopyrimidine reacts in acidic aqueous media with selenium (IV) to give a piazselenol which has an absorption maximum at 362 nm with a molar absorptivity of 1.72 x 10(4) 1.mole(-1).cm(-1). The compound is stable but not extractable into non-polar solvents. The calibration graph is linear up to 10 ppm of selenium, with a detection limit of 0.1 ppm in the sample solutions. Of the many different ions tested only iron (III) (in the presence of chloride) and tin (II) interfere. The method has good reproducibility, with a relative standard deviation of 1.5% for pure solutions. The application of this method to analysis of water and electrolytic copper is described.