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Biomedical subjects

N Bianchi

Publications and source records attributed to N Bianchi.

At least 73 records · Page 4Linked to original sources
PubMed1997

Double interdomal suture in nasal tip sculpturing.

The authors stress that conservative correction should be the main goal in rhinoplasty in general and in the surgical treatment of the nasal tip in particular. After outlining contemporary concepts and criteria relating to the modeling of an aesthetically pleasing nasal tip and the consequent surgical planning for its achievement as well as the specific indications for tip plasty, they go on discuss the technical aspects of tip projection and rotation. A personal technique is proposed for reshaping and sculpturing the tip, completed by a double interdomal suture with different application points during closed rhinoplasty. The technique also involves ancillary procedures consisting in the execution of a series of incisions with a radial pattern at the domal level and, when necessary, in the undersurface of the lateral crus. The procedure is explained in detail and the results are illustrated and discussed.

Esthetics↗
PubMed1997

Synthesis, cytotoxicity, antitumor activity and sequence selective binding of two pyrazole analogs structurally related to the antitumor agents U-71,184 and adozelesin.

Two pyrazole analogs structurally related to the antitumor agents adozelesin and U-71,184 respectively were synthesized. By using a polymerase chain reaction approach, both compounds show selective binding to A + T rich sequences exactly as reference compound U-71,184. In in vitro assays, against L1210 cell lines, both derivatives showed cytotoxicity in the pM range, values comparable with the natural target compound (+)-CC-1065. The most active compound showed very high antitumor activity in mice implanted with L1210 cells (ILS% 363).

Animals↗
PubMed1996

Targeting of the Sp1 binding sites of HIV-1 long terminal repeat with chromomycin. Disruption of nuclear factor.DNA complexes and inhibition of in vitro transcription.

Sequence selectivity of DNA-binding drugs has recently been reported in a number of studies employing footprinting and gel retardation approaches. In this paper, we studied the biochemical effects of the sequence-selective binding of chromomycin to the long terminal repeat of the human immunodeficiency type I virus. Deoxyribonuclease I (E.C.3.1.21.1) footprinting, arrested polymerase chain reaction, gel retardation and in vitro transcription experiments have demonstrated that chromomycin preferentially interacts with the binding sites of the promoter-specific transcription factor Sp1. Accordingly, interactions between nuclear proteins and Sp1 binding sites are inhibited by chromomycin, and this effect leads to a sharp inhibition of in vitro transcription.

Base Sequence↗
PubMed1996

Magnetic resonance imaging in primary and secondary septorhinoplasty.

The authors emphasize the importance of MRI as a means to functionally evaluate patients in primary (PR) and secondary (SR) rhinoseptoplasty. Forty-eight subjects were appraised who underwent various types of corrective nose surgery: 31 PR, 12 SR, 4 introgenic perforations, and 1 dermoid cyst of the nasal dorsum. MRI allows the nasal structures at the level of the valve to be visualized, as well as the medial and lateral walls of the nasal fossa in all of its components. MRI studies improve pre-surgical evaluation (alar cartilages, iaterdomal distance, and valvular configuration), and the exam of structures and anomalies which are hard to evaluate by the rhinoscopy (turbino-septal-synchias, perforations, losses of bone-cartilaginous substance). Moreover, through MRI the nasal respiratory surface (NRS) is determined and used by the authors to quantify the improvement of the postsurgical nasal respiratory function. All of these points gain importance during the planning of primary, secondary, and/or corrective surgery.

Adult↗
PubMed1995

Binding of distamycin and chromomycin to human immunodeficiency type 1 virus DNA: a non-radioactive automated footprinting study.

Sequence-selectivity of DNA-binding drugs was recently reported in a number of studies employing footprinting and gel retardation approaches. In this paper we studied sequence-selectivity of the binding of chromomycin and distamycin to DNA by performing DNase I footprinting and analysis of the cleaved fragments by the Pharmacia ALF DNA Sequencing System. As a model system we employed the long terminal repeat of the human immunodeficiency type 1 virus. The main conclusion of our experiments is that automated analysis of DNase I footprinting is a fast and reliable technique to study drugs-DNA interactions. The results obtained suggest that distamycin and chromomycin differentially interact with the long terminal repeat of the human immunodeficiency type 1 virus; this differential binding depends upon the DNA sequences recognized. The data presented are consistent with a preferential binding of distamycin to DNA sequences of the binding sites of nuclear factor kappa B and transcription factor IID. By contrast, distamycin exhibits only weak binding to DNA sequences recognized by the promoter-specific transcription factor Sp1. Unlike distamycin, chromomycin preferentially interacts with the binding sites of the promoter-specific transcription factor Sp1.

Antibiotics, Antineoplastic↗
PubMed1995

Differential effects of distamycin analogues on amplification of human gene sequences by polymerase-chain reaction.

In this report we analyse the effects of distamycin and five distamycin analogues on amplification by polymerase-chain reaction (PCR) of two gene sequences displaying a different A+T/G+C content. The first was a 5' region of the human oestrogen receptor (ER) gene, containing a (TA)26 stretch; the second was a CG-rich sequence of the human Ha-ras oncogene. The results obtained unequivocally demonstrate that the addition of one pyrrole ring significantly improves the ability of distamycin derivatives to interfere with PCR-mediated amplification of the human ER genomic region carrying a (TA)26 stretch. The distamycin analogues analysed differ in the number of pyrrole rings and in the presence of an N-formyl, an N-formimidoyl or a retroamide group at position X1. Among compounds carrying the same number of pyrrole rings, those carrying an N-formyl or an N-formimidoyl group retain a similar inhibitory activity. The retroamide analogues, on the contrary, are much less efficient in inhibiting PCR-mediated amplification of the 5'ER region. With respect to sequence selectivity both distamycin and distamycin analogues exhibit a sequence preference, since they do not inhibit PCR amplification of Ha-ras CG-rich gene regions, with the exception of a distamycin analogue carrying four pyrrole rings.

Base Composition↗
PubMed1995

Sequencing of an upstream region of the human HLA-DRA gene containing X' and Y' boxes.

In this paper we report the characterization of a newly sequenced 5' upstream region of the human HLA-DRA gene. We performed (i) search for transcription factor motifs, (ii) analysis of CpG display and observed/expected frequency ratios, (iii) search for regions homologous to the 5' upstream sequences of the murine EA gene, (iv) DNase I footprinting experiments and (v) electrophoretic mobility shift assays. Our results demonstrate the existence, in the HLA-DRA gene, of Y' and X' boxes highly homologous to the Y and X boxes present in MHC class II genes, but oriented in the opposite direction. These Y' and X' boxes have been conserved during the molecular evolution of both human HLA-DRA and murine EA genes. DNase I footprinting and gel retardation experiments suggest that the X' and Y' boxes of the HLA-DRA upstream gene region are specifically recognized by nuclear proteins that also bind to the X and Y boxes of the HLA-DRA proximal promoter, respectively.

Animals↗
PubMed1995

Alteration of the expression of human estrogen receptor gene by distamycin.

The effects of distamycin on the expression of the estrogen receptor gene were determined in the MCF7 human breast cancer cell line. Estrogen receptor (ER) RNA transcripts were analyzed by Northern blotting and RT-PCR using specific oligonucleotides for the 5' upstream region and for ER cDNA. After ex vivo distamycin treatment of the cells the expression of the canonical ER mRNA isoform of 6.3 kb is strongly inhibited, without appreciable alteration of the accumulation of 5' upstream ER mRNA isoforms. These results suggest that distamycin alters the transcriptional activity of the ER gene causing a change in the ratio between the canonical transcript and other isoforms containing 5' upstream regions.

Antiviral Agents↗
PubMed1994

A chromatographic procedure for fully automated isolation of DNA from human whole blood.

Isolation of DNA from peripheral blood constitutes a fundamental step in the molecular diagnosis of genetic disorders, analysis of mutations of oncogenes and detection of nucleic-acid sequences of pathogenic organisms in clinical samples. We investigated whether dextran sedimentation of blood followed by the chromatographic isolation of DNA could be applied to the Biomek-1000 automated laboratory workstation in order to develop a fully automated method of DNA isolation from whole blood. Under our experimental conditions, the Biomek-1000 could perform fully automated DNA isolation from seven human whole blood samples in less than 1.5 h. Our data indicate that the DNA isolated from human blood in this way is suitable for polymerase chain reaction.

Autoanalysis↗
PubMed1994

Polymerase-chain reaction as a tool for investigations on sequence-selectivity of DNA-drugs interactions.

Sequence-selectivity of DNA-binding drugs was recently reported in a number of studies employing footprinting and gel retardation approaches. In this paper we performed polymerase-chain reaction (PCR) experiments to study the in vitro effects of distamycin, daunomycin, chromomycin and mithramycin. As model systems we employed the human estrogen receptor (ER) gene and the Harvey-ras (Ha-ras) oncogene, in order to obtain PCR products significantly differing for the A + T/G + C frequency ratio. Distamycin, daunomycin, chromomycin and mithramycin are indeed known to differentially bind to different DNA regions depending upon the DNA sequences recognized. The main conclusion of our experiments is that distamycin, daunomycin, chromomycin and mithramycin inhibit polymerase-chain reaction in a sequence-dependent manner. Distamycin inhibits indeed PCR mediated amplification of AT-rich regions of the human estrogen receptor gene, displaying no inhibitory effects on PCR-mediated amplification of GC-rich sequences of Ha-ras oncogene. By contrast daunomycin, chromomycin and mithramycin were found to inhibit PCR-mediated amplification of the Ha-ras GC-rich oncogene sequences. We propose that polymerase-chain reaction technique could be applied to study the in vivo interactions of DNA-binding drugs to specific genes in intact cells.

Animals↗
PubMed1994

Capillary electrophoresis: detection of hybridization between synthetic oligonucleotides and HIV-1 genomic DNA amplified by polymerase-chain reaction.

The polymerase chain reaction (PCR) is one of the most efficient techniques for measuring the viral load of HIV-infected samples. Determination of the specificity of PCR products is usually based on Southern blotting and hybridization of the amplified DNA to radioactive oligonucleotide probes specific for sequences comprised between the PCR primers. The recent introduction of capillary electrophoresis (CE) for identification of HIV-1 and HTLV-I PCR products appears interesting in light of its reproducibility, sensitivity and because it is fast and suitable for detection of DNA/DNA and DNA/RNA hybrids. We demonstrate that specific hybridization of a HIV-1 oligonucleotide probe to single-stranded DNA obtained by unbalanced PCR is detectable by capillary electrophoresis. This enabled us the application of a one-step, non-radioactive protocol to demonstrate the specificity of amplification of HIV-1 genomic sequences by PCR. This procedure is simple, reproducible and is suggested as an integral part of automated diagnostic systems based on the use of laboratory work stations for DNA isolation, preparation of PCR reactions and analysis of PCR products.

Base Sequence↗
PubMed1994

Loss of heterozygosity in ovarian cancer: detection by PCR and microsatellite polymorphism.

Loss of chromosome 6q was investigated in endometrial and ovarian carcinomas by a PCR based-microsatellite polymorphism analysis. Results obtained show that this technique is able to detect frequent loss of heterozygosity in the ovarian cancers (10/27) and only in the serous type (8/17). Then, this kind of analysis can contribute to the understanding of tumor development and progression of ovarian cancers with different histopathological features.

Base Sequence↗
PubMed1993

Sequencing of an RNA transcript of the human estrogen receptor gene: evidence for a new transcriptional event.

Two transcripts of the human estrogen receptor (ER) gene have been described, ER mRNA 1 and mRNA 2, different in their 5' untranslated region. By performing reverse transcriptase-polymerase chain reaction with oligonucleotides specific for the 5' genomic region of the human ER gene we have identified a new ER RNA transcript. The sequence analysis of cDNA from MCF7 breast cancer cells and endometrial human tissues demonstrates that this transcript originates further upstream of the initiation transcription sites so far proposed. Primer extension analysis on RNA from MCF7 cells reveals in the upstream region a possible transcription start site at -3090. In agreement with this result, Northern blot analysis shows, in addition to the canonical 6.3 kb ER mRNA, an ER RNA transcript of approx. 7.4 kb in size. The presence of the additional ER mRNA suggests the existence of a new upstream 5' promoter directing transcription of the human ER gene.

Base Sequence↗