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Biomedical subjects

D Balducci

Publications and source records attributed to D Balducci.

At least 37 records · Page 2Linked to original sources

Qualitative and quantitative evaluation of chrysotile and crocidolite fibres with infrared spectrophotometry: application to asbestos-cement products.

Infrared (IR) spectrophotometry allows simple and rapid qualitative and quantitative evaluations of different types of asbestos, as well as of other inorganic particles. In particular, chrysotile and crocidolite have characteristic IR spectra, and optical density measurements in the 2710 nm band for chrysotile and the 12820 nm band for crocidolite permit the quantitative evaluation of each fibre either alone or in mixtures. IR spectra also provide information on changes in fibre structure and in chemical composition as the result, for example, of thermal treatment or acid leaching. The analytical method that we have developed can detect amounts as small as 0.1 mg of fibre in a 300-mg disk of potassium bromide using a low-cost IR spectrophotometer. The use of a Fourier transform IR spectrophotometer dramatically improves the sensitivity and selectivity. Computer-assisted analysis of spectra offers the possibility of reducing matrix interference and of comparing different spectra. The application of the IR technique to asbestos-cement products and insulating materials is described.

Asbestos↗

Etoposide in recurrent childhood Langerhans' cell histiocytosis: an Italian cooperative study.

Eighteen evaluable children with recurrent Langerhans' cell histiocytosis (LCH) which was resistant to standard therapy, were treated with etoposide (VP 16-213), 200 mg/m2/day for 3 days every 3 weeks, to study the efficacy and toxicity of this drug. Complete and partial responses were demonstrated in 15 patients (83.3%). Only one of the 12 children achieving a complete remission has relapsed. No dose-limiting major toxicities were registered. Although etoposide might be an effective treatment in recurrent LCH which needs a chemotherapeutic approach, it is emphasized that this drug must be used carefully.

Child↗

Height of children off therapy after acute lymphoblastic leukemia.

A total of 290 children off therapy after acute lymphoblastic leukemia, in continuous complete remission for at least 2 years, were evaluated for height at the onset of the disease and at the most recent clinical visit (median time after suspension of treatment 4 years 4 months, range 2 years-11 years 3 months). All patients had been treated with multidrug schedules; intrathecal drugs had been given to 84% of the patients for prevention of CNS involvement, associated with radiotherapy. The height percentiles at the most recent examination were shifted downward significantly compared with the expected pattern (p less than 0.001). The effect on stature was much more marked in girls, with a reduction of height percentiles at most recent examination from expected and from diagnosis; in males there was a reduction from diagnosis to latest follow-up, but the values were within the limits of normal. The short stature was mostly observed in pubertal girls and in patients who had undergone radiotherapy.

Antineoplastic Agents↗

Adsorption of proteins by chrysotile and crocidolite: role of molecular weight and charge density.

Transferrin, gamma-globulin, fibrinogen, aldolase, albumin, and cytochrome c at concentration of 0.45 muMole/liter were treated with chrysotile and crocidolite fibers. Specific adsorption for each protein and correlations between protein molecular weight and charge density in experimental conditions were evaluated. Chrysotile showed the highest absorption capability, particularly toward albumin and cytochrome c. Affinity for fibers was poorly linked to protein molecular weight; on the contrary, a good correlation with protein charge density was found. The sign of charge on fibers and proteins seemed to play a minor role in adsorption.

Adsorption↗

Selective adsorption of serum proteins by chrysotile and crocidolite.

Two distinct and contemporaneous adsorption mechanisms occur when serum proteins are incubated with chrysotile and crocidolite. The first one appears to be reversible and nonspecific, independent of the characteristics of the protein and the fiber surface. The second process seems to depend on fiber type and to involve only some protein species that are strongly concentrated on the fiber surface. This latter adsorption mechanism appears to be electrostatic in nature.

Adsorption↗

Qualitative and quantitative evaluation of chrysotile and crocidolite fibers with IR-spectroscopy: application to asbestos-cement products.

Infrared (IR) spectrophotometry allows simple and quick qualitative and quantitative evaluations of different kinds of asbestos, as well as of other inorganic particles. In particular, chrysotile and crocidolite have characteristic IR spectra and optical density measures of 2,710 nm band for chrysotile, of 12,820 nm band for crocidolite permit quantitative evaluation of each fiber alone or in mixture. IR spectra also give informations about changes of fiber structure and of chemical composition due, for example, to thermal treatment or acid leaching. The analytical method we developed can detect levels as low as 0.1 mg of fiber in a 300 mg disk of KBr using a low cost IR spectrophotometer. The use of a Fourier Transform IR spectrophotometer (FTIR) improves dramatically the sensitivity and selectivity. Computer assisted analysis of spectra offers the possibility to reduce matrix interferences and to compare different spectra. Examples of IR technique applied to asbestos-cement products and insulating materials are presented.

Asbestos↗

[Experience in the use of the tumor markers CEA, GICA and TPA in the postoperative monitoring of colorectal neoplasms].

Current use of tumour markers in the followup to malignant digestive tract neoplasias is restricted mainly by the non optimal sensitivity levels and specificity of these markers. These aspects of CEA, GICA and TPA markers used in follow-ups for 23 patients surgically treated for Duke's stage B2 neoplasias of the colon and rectum were examined over the period 1980-1983. Each marker examined displays its own individual characteristics of sensitivity and specificity. An X-ray endoscopic confirmation is required in all cases as no single marker is sufficiently reliable to be used as a diagnostic tool on its own. It is concluded that biological markers should be used as part of a follow-up programme embracing more than one diagnostic procedure.

Antigens, Neoplasm↗