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Biomedical subjects

C Bailly

Publications and source records attributed to C Bailly.

At least 307 records · Page 17Linked to original sources
PubMed1979

[Maxillodental problems after irradiation in children (author's transl)].

The treatment of a certain number of children with very severe dentomaxillary sequelae after radiotherapy for facial and intracranial lesions raises many problems. These include the type of reconstructive therapy, the protection of the maxillodental structures, the value of local and alimentary hygiene, and the quantity and quality of dental treatment needed. Further difficulties are encountered because of dental malformations (absence of roots), increased rate of eruption of the teeth in the arch (contrary to the accepted opinions), and objectives should be modest when attempting maxillofacial orthopedic procedures.

Adolescent↗
PubMed1979

[Value of ultrastructural morphology in the preparation of oncolysates of human malignant melanoma].

The culture of human cutaneous malignant melanomas is an important stage in the preparation of oncolysates for therapeutic purposes. The authors recall the definition of oncolysate: lysis of the malignant melanocyte by vaccinia virus liberates masked antigens which when reinjected into the patient accelerate or restimulate the production of antibodies. Culture is used to increase the number of malignant melanocytes, i. e. antigenic material, which is an essential precaution in tumours of small size. Production of oncolysate requires the exclusive use of the malignant melanocyte, i. e. the importance of morphological identification during the "in vitro" phase. The optical criteria defined by Fedoroff are inadequate and a source of error. Ultrastructural studies render this identification more valid, insofar as the normal and pathological markers which are the melanosomes are better known. Ultrastructural studies may be used to differentiate the malignant melanocyte from the ordinary macrophage in media which are black, and light cultures to distinguish fibroblastic growth, with no antigenic value, from the malignant melanocyte without pigment (achromic), recognisable by its premelanosome.

Antigens, Neoplasm↗
PubMed1979

[Experimental study of the relative biological effectiveness (R.B.E.) of a fast neutron beam (author's transl)].

A preliminary experimentation has been done with the synchrocyclotron (28 MeV deuton) in Lyon. The different characteristics of the beam have been determined through various dosimetric measurements. C57Bl mice have been irradiated with single doses and fractionated schedules (5 sessions). 7 day survival has been analysed. Comparison of neutron and cobalt gamma ray shows a R.B.E. of 1.95 for single dose and 2.5 for five fractions. This work is a confirmation of the effect of fractionation on the R.B.E. of the neutrons.

Animals↗
PubMed1977

A new topographic approach to the spread of breast cancer: the grid method.

In a series of 181 patients with breast cancer treated by mastectomy with axillary lymph node dissection, the authors developed and used an improved topographic technique, which they call the "Grid Method", which maps out the extent of a given cance of the breast. Three types of tumor spread are defined: Type 1, limited (L)(31%); Type 2, multifocal (M)(13.2%); and Type 3, extensive (E)(55.8%). This topographic information allows a more accurate assessment of prognosis when used in conjunction with the morphologic findings. Moreover, the topographic "Grid" study is simple to perform and easy to assess. Of prime importance is the relationship between the topographic and mammographic findings.

Axilla↗
PubMed1977

A topographic approach to breast cancer: the relation of topographic and mammographic findings.

One hundred and twenty-eight patients with breast cancer who, on the basis of mammographic study, were treated by mastectomy were analyzed. The purpose of this endeavor was to correlate the roentgenologic features with the pathologic findings. The correlation between them was very good: the type of tumor opacity, the microcalcifications, and the various other radiologic patterns were compatible with both localized and extensive breast cancer. Mammography appears to be valuable in the selection of patients suitable for conservative treatment.

Breast Neoplasms↗
PubMedDate not supplied

The influence of the exocyclic amino group characteristic of GC base pairs on molecular recognition of specific nucleotide sequences in DNA by berenil and DAPI.

The expedient of preparing homologous DNA samples substituted with inosine for guanosine residues, 2,6-diaminopurine (DAP) for adenine residues, or both, has been used to investigate the role of the purine 2-amino group in determining the preferred binding sites for the drugs berenil [1,3-bis(4-phenylamidinium) triazene] and DAPI (4',6-diamidino-2-phenyl indole) on DNA. The selectivity of these two minor groove binders for AT-rich sequences is seen to be radically altered in the substituted DNA molecules. Neither berenil nor DAPI bind to DAP-substituted DNA where all purine residues bear a 2-amino group. By contrast, they bind to AT-rich, IC-rich and even mixed sequences of the inosine DNA where all purine residues lack the 2-amino group. With the inosine and DAP double substituted DNA, both berenil and DAPI bind preferentially to IC-rich clusters instead of their canonical tracts endowed with an extra 2-amino group through substitution with DAP. These results establish that the location of the purine 2-amino group represents a critical determinant for recognition of DNA nucleotide sequences by the two drugs.

2-Aminopurine↗
PubMedDate not supplied

Triple helix-forming oligonucleotides conjugated to indolocarbazole poisons direct topoisomerase I-mediated DNA cleavage to a specific site.

Topoisomerase I is an ubiquitous DNA-cleaving enzyme and an important therapeutic target in cancer chemotherapy for camptothecins as well as for indolocarbazole antibiotics such as rebeccamycin. To achieve a sequence-specific cleavage of DNA by topoisomerase I, a triple helix-forming oligonucleotide was covalently linked to indolocarbazole-type topoisomerase I poisons. The three indolocarbazole-oligonucleotide conjugates investigated were able to direct topoisomerase I cleavage at a specific site based upon sequence recognition by triplex formation. The efficacy of topoisomerase I-mediated DNA cleavage depends markedly on the intrinsic potency of the drug. We show that DNA cleavage depends also upon the length of the linker arm between the triplex-forming oligonucleotide and the drug. Based on a known structure of the DNA-topoisomerase I complex, a molecular model of the oligonucleotide conjugates bound to the DNA-topoisomerase I complex was elaborated to facilitate the design of a potent topoisomerase I inhibitor-oligonucleotide conjugate with an optimized linker between the two moieties. The resulting oligonucleotide-indolocarbazole conjugate at 10 nM induced cleavage at the triple helix site 2-fold more efficiently than 5 microM of free indolocarbazole, while the other drug-sensitive sites were not cleaved. The rational design of drug-oligonucleotide conjugates carrying a DNA topoisomerase poison may be exploited to improve the efficacy and selectivity of chemotherapeutic cancer treatments by targeting specific genes and reducing drug toxicity.

Aminoglycosides↗
PubMedDate not supplied

Antitumor combilexin. A thiazole-containing analogue of netropsin linked to an acridine chromophore.

We report the synthesis, DNA-binding properties and antitumor activity of ThiaNetGA, a hybrid molecule in which are conjugated a thiazole-lexitropsin and an intercalating anilinoacridine chromophore. This combilexin molecule binds to DNA via a bimodal process involving minor groove binding of the lexitropsin moiety and intercalation of the acridine moiety. The uptake and distribution of the hybrid in L1210 leukemia cells were investigated by ESR spectroscopy using a spin-labeled derivative. The nitroxide-containing conjugate accumulates preferentially in the cell nuclei and rapidly saturates the nuclear receptor sites. Both in vitro and in vivo assays indicate that the drug is practically nontoxic but exhibits moderate antitumor activity against P388 leukemia cells in mice.

Acridines↗
PubMedDate not supplied

Synthesis, DNA binding, and cleaving properties of an ellipticine-salen.copper conjugate.

The synthesis of a DNA-cutting agent that conjugates an ellipticine chromophore and a copper complex of bis(salicylidene)ethylenediamine, referred to as a salen, is reported. The presence of the salen.Cu complex allows cleavage of DNA via oxygen-based radicals, and the ellipticine moiety serves as a DNA anchor. Spectroscopic measurements indicate that the intercalation geometry of the ellipticine chromophore is preserved with the hybrid. The cleavage is much more efficient with the conjugate than with the Schiff base copper complex alone.

Chelating Agents↗
PubMedDate not supplied

Sequence-recognition and cleavage of DNA by a netropsin-phenazine-di-N-oxide conjugate.

We report the synthesis, DNA-binding and cleaving properties, and cytotoxic activities of R-128, a hybrid molecule in which a bis-pyrrolecarboxamide-amidine element related to the antibiotic netropsin is covalently tethered to a phenazine-di-N-oxide chromophore. The affinity and mode of interaction of the conjugate with DNA were investigated by a combination of absorption spectroscopy, circular dichroism, and electric linear dichroism. This hybrid molecule binds to AT-rich sequences of DNA via a bimodal process involving minor groove binding of the netropsin moiety and intercalation of the phenazine moiety. The bidentate mode of binding was evidenced by linear dichroism using calf thymus DNA and poly(dA-dT).(dA-dT). In contrast, the drug fails to bind to poly(dG-dC).poly(dG-dC), because of the obstructive effect of the guanine 2-amino group exposed in the minor groove of this polynucleotide. DNase I footprinting studies indicated that the conjugate interacts preferentially with AT-rich sequences, but the cleavage of DNA in the presence of a reducing agent can occur at different sequences not restricted to the AT sites. The main cleavage sites were detected with a periodicity of about 10 base pairs corresponding to approximately one turn of the double helix. This suggests that the cleavage may be dictated by the structure of the double helix rather than the primary nucleotide sequence. The conjugate which is moderately toxic to cancer cells complements the tool box of reagents which can be utilized to produce DNA strand scission. The DNA cleaving properties of R-128 entreat further exploration into the use of phenazine-di-N-oxides as tools for investigating DNA structure.

Animals↗
PubMedDate not supplied

A bio-anthropological study on the Bakakas of Cameroon.

Bakakas are native Bantus belonging to the Mbo-Bakossi group, peopling the Cameroon's Littoral region. In the context of a wide bio-anthropological study project focused on the bio-historical processes involved in the areas, 278 adults of both sexes from the villages of Ebone and Bakwat (Bakaka Canton) were investigated for 14 erythrocyte and serum genetic polymorphisms (ACP1, ADA, EsD, GLO, Hb beta, GPX1, CAII, PGM1, SAHH, 6-PGD, Hp, Pi, Gc and Tf). With only a few exceptions (Hp and GLO systems), the genetic frequencies of the polymorphisms considered tend to fall within the range of variation known for the subsaharan populations. With reference to the malaria endemicity characterizing the Littoral environment, high frequencies for Hb beta*S allele and absence of the ACP1*R 'Negro allele' were recorded. The genetic distances among Bakakas and 14 other Central African populations were also calculated from six genetic loci.

Adult↗
PubMedDate not supplied

Molecular recognition of quadruplex DNA by quinacridine derivatives.

The interaction of monomeric and dimeric quinacridines with quadruplex DNA has been investigated using a variety of biophysical methods. Both series of compounds were shown to exhibit a high affinity for the G4 conformation with two equivalent binding sites. As shown from the SPR and dialysis experiments the macrocyclic dimer appears more selective than its monomeric counterpart.

Base Sequence↗