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Biomedical subjects

F Quadrifoglio

Publications and source records attributed to F Quadrifoglio.

71 records · Page 4Linked to original sources
PubMed1975

The interaction of natural tetra-azacyclopentazulene dyes with DNA and their effects on the DNA and RNA polymerase reactions.

The interaction of two natural tetra-azacyclopentazulene dyes with native calf thymus DNA was studied by means of microcalorimetric, viscosimetric, and spectroscopic measurements. The results are consistent with the hypothesis of an intercalative-binding. However, comparison of calorimetric studies shows that the changes in enthalpy associated with the interaction of these compounds with DNA are, in absolute value, significantly lower than those found with known intercalating agnets (daunomycin, ethidium bromide). The influence of these dyes on the template capacity of DNA in the in vitro synthesis of nucleic acids was also determined. Under the conditions used, these compounds selectively inhibited DNA synthesis. No appreciable inhibitory effect upon E. coli RNA polymerase was observed. Both compounds had greater inhibitory effect on rat liver high molecular weight DNA polymerase than E. coli DNA polymerase I. Zoanthoxanthin was a more effective inhibitor than 3-norzoanthoxanthin.

Animals↗
PubMedDate not supplied

Effect of oligomer length and base substitutions on the cytotoxic activity and specific nuclear protein recognition of GTn oligonucleotides in the human leukemic CCRF-CEM cell line.

We have identified phosphodiester oligonucleotides composed of G and T bases, named GTn, which are able to inhibit the cellular growth of human cancer cell lines by recognising specific nuclear proteins. We demonstrated that GTn oligonucleotides require a length of at least 20 nucleotides in order to exert a significant cytotoxic effect and to retain the specific protein binding ability. In addition, we found that GTn cytotoxicity was lost when A or C bases were introduced at either 3' and 5' end or within the GTn sequences.

Biopolymers↗
PubMedDate not supplied

[Interaction of ethidium bromide with synthetic double-stranded polyribonucleotides].

The interaction of ethidium bromide (EtBr) with double helical synthetic polyribonucleotides poly(G).poly(C), poly(A).poly(U) and poly(I).poly(C) has been investigated by the method of isothermal microcalorimetry and according to the character of changes on the spectra of circular dichroism, absorption and fluorescence at binding. The calculations showed that at binding of EtBr with poly(A).poly(U) the saturation stechiometry was one EtBr molecule per 2 base pairs with binding constant (2.5 +/- 0.5).10(6) M-1 at 30 degrees C and 0.1 M. NaCl. In the case of binding of EtBr with poly(G).poly(C) and poly(I).poly(C) the saturation stechiometry was not less than 0.2 EtBr molecule per 1 base pair with binding constant (4 +/- 1).10(3) M-1 and (1.5 +/- 0.3).10(4) M-1 respectively, at 25 degrees C and 0.1 M NaCl. The binding enthalpies of EtBr with poly(A).poly(U) and poly(G).poly(C) have been determined to be (-7.5 +/- 0.5) Kcal per 1 mol of bound EtBr in average for both polymers. It has been shown that the observed strong selectivity of EtBr binding with polyribonucleotides is of entropic origin.

Circular Dichroism↗
PubMedDate not supplied

[Anti-alpha-gliadin antibodies. Sensitivity, specificity and correlation with blood xylose test in the 3 diagnostic stages of celiac disease in children].

The specificity and sensibility of IgA and IgG alfagliadin antibody test (AaGA) for screening, diagnosis and follow-up of childhood coeliac disease has been evaluated. We have compared AaGA test to D-xylose blood test and at last we have examined the false positive and negative results given by the test. Two groups of subjects were considered: 1) 90 children with untreated coeliac disease (21 newly diagnosed (I stage), 50 in gluten withdrawal (II stage), 19 in challenge (III stage); 2) 255 disease controls including: 157 healthy controls; 31 children with gastroenterological disorders other than coeliac disease; 31 children with food allergy and atopic dermatitis; 36 children with "constitutional" short stature (without GH deficiency and with normal intestinal mucosa). The sensibility of AaGA test in the first stage of coeliac disease has been of 95.2% for the IgG class antibody and 90.4% for the IgA class; on the other hand the showed a specificity of 83.6% for IgG class antibody and 96.9% for IgA class. In only two newly diagnosed coeliac children we have found false negative results: in the first case the patient was IgA-deficient, in the second the age was above 3 years. AaGA IgA resulted positive only in the 12.9% of the group of gastroenterological and atopic controls; particularly most cases were affected by multiple food allergies and two patients by chronic autoimmune disease of small intestine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Restoring uptake and retention of daunorubicin and idarubicin in P170-related multidrug resistance cells by low concentration D-verapamil, cyclosporin-A and SDZ PSC 833.

BACKGROUND: Overexpression of the mdr-1 gene that codes for a 170 Kd transmembrane glycoprotein (P170) is a factor responsible for decreased cell sensitivity to anthracyclines and other drugs, and is related to treatment failure in acute leukemia and other tumors. Several agents, including verapamil and cyclosporine derivatives, can modify P170-related resistance in vitro and can be proposed as adjuvant treatment for leukemia and cancer. MATERIALS AND METHODS: To investigate the optimal conditions for adjuvant treatment, D-verapamil (D-VRP), cyclosporin-A (CyA) and the cyclosporine derivative SDZ PSC 833 (PSC) were used alone and in combination at drug concentrations that can be achieved and maintained in vivo. The drugs were tested for their capacity to restore intracellular daunorubicin (DNR) and idarubicin (IDA) accumulation in high-resistance (CEM VLB 300) and intermediate-resistance (CEM VLB 100) cells to levels found in the non-resistant parental cell line (CCRF CEM). RESULTS: In intermediate-resistance cells, IDA alone was more easily restored than DNR plus modifiers, and intracellular IDA concentration was returned to the level of non-resistant cells with low-dose D-VRP (1 microM), CyA (0.8 microM) and PSC (0.4 microM). In high-resistance cells no modifier or modifier combination was able to restore intracellular DNR concentration to the value of non-resistant cells. Intracellular IDA concentration was almost completely restored only with D-VRP (2-3 microM) and CyA (0.8-1.6 microM) in combination or with PSC alone (0.4 microM). CONCLUSIONS: These data suggest that as far as P170-related resistance is concerned, IDA alone is as efficient as or even more efficient than DNR plus modifiers, and that residual resistance to IDA can be overcome with a combination of D-VRP and Cy-A at a clinically achievable concentration, or with a more powerful modifier like SDZ PSC 833.

ATP Binding Cassette Transporter, Subfamily B, Mem↗