Biomedical subjects

R Mastrippolito

Publications and source records attributed to R Mastrippolito.

7 recordsLinked to original sources

PubMed2002

The potential of the beta-Microprobe, an intracerebral radiosensitive probe, to monitor the [(18)F]MPPF binding in the rat dorsal raphe nucleus.

The aim of this study was to demonstrate the ability of a recently developed beta(+)-range sensitive intracerebral probe (beta-Microprobe) to measure the binding kinetics of [(18)F]MPPF, a well-documented 5-HT(1A) serotoninergic receptor ligand, in the dorsal raphe nucleus (DRN) of the anaesthetised rat. This midbrain nucleus presents a high concentration of 5-HT(1A) receptors known to be implicated in the effects of antidepressants. The difficulty confronting this study lay in the fact that the dimensions of the DRN are smaller than the detection volume of the beta-Microprobe. In the first part of the study, we studied the feasibility of this measurement from a theoretical point of view by autoradiography and a Monte Carlo simulation. We determined the optimal beta-Microprobe location close to the DRN and verified that this configuration allowed accurate determination of [(18)F]MPPF specific binding in the nucleus. In the second part of our study, we measured the in vivo time-concentration curves of [(18)F]MPPF binding in the DRN in comparison with the cerebellum. The specificity of [(18)F]MPPF binding in the DRN was confirmed by its displacement after non-labelled 5-HT(1A)antagonist injection (MPPF or WAY-100635). Moreover, we verified the feasibility of using beta-Microprobe monitoring and simultaneous validation by microdialysis to study the effect of an increase in extracellular serotonin, induced by fenfluramine injection, on [(18)F]MPPF binding in the DRN. Our theoretical simulations, confirmed by our experimental results, demonstrate the ability of this new device to monitor in vivo the binding of [(18)F]MPPF in the DRN of anaesthetised rodents.

Aminopyridines↗

PubMed1998

A new high resolution radioimager for the quantitative analysis of radiolabelled molecules in tissue section.

We present a high-speed, high-resolution imager of beta particles. It is devoted to be used in autoradiography experiments such as receptor binding or in situ hybridization experiments, either instead of, or in complement with autoradiographic film and emulsions. It allows the user to locate and perform quantitative analyses of (3H, 14C, 35S, 33P, 32P, 125I) labelled molecules with a 15 microm spatial resolution on a 0.9 x 1.3 cm2 sensitive area. Combining recent techniques (specific scintillator thin sheets and intensified charge-coupled device (CCD)) this imager offers a wide dynamic range and real-time acquisition.

Animals↗

PubMed1998

In vivo radiolabel quantification in small-animal models.

Current developments in emission tomography especially designed for small-animal imaging are presented. Adaptations of the human tomography principles take advantage of the smaller field of view to achieve about 2-mm usable resolution. Some evaluations in rat tomography are presented, and the problems of limiting resolution of PET and SPECT systems are discussed. Finally, a new approach that more specifically takes into account the parameters induced by in vivo quantification in rodents is presented.

Animals↗

PubMed1996

Radioimager quantification of oligonucleotide hybridization with DNA immobilized on transfer membrane: application to the identification of related sequences.

The radioimager scintillating optical fiber imager was used to quantify the hybridization parameters of a 35-mer oligonucleotide probe with target DNAs immobilized on transfer membranes. The amount of the immobilized target DNA remaining accessible to hybridization (Rt) was shown to be about 4% of the spotted DNA. The time course of the hybridization of a target DNA reacting with an excess of full-match probe exhibited a first-order kinetics, in which rate constant k was the highest for the hybridization temperature close to the calculated Tm. The effect of temperature on the hybridization kinetics of the probe sharing 37 to 100% identity with the immobilized target DNA was assessed: A significant fall of both the rate constant k and Rt values at the plateau was observed when the identity shared by the target DNA and the probe decreased from 100 to 71%. The highest k and Rt values were also obtained for temperatures closest to the calculated Tm. A good estimate of the degree of sequence identity may be calculated from the corresponding hybridization signals. Washing procedure did not improve the discrimination between related sequences, except for closely similar sequences. Practical conclusions for the detection of sequences belonging to gene families are presented.

Base Sequence↗

PubMed1994

HRRI: a high resolution radioimager for fast, direct quantification in in situ hybridization experiments.

We present a high-speed, high-resolution beta imager. It has been developed to be used in in situ hybridization experiments, either instead of or in complement with autoradiographic film and emulsions that are currently used for these experiments. It allows the user to locate and perform quantitative analyses of (3H-, 14C-, 35S-, 32P-, 125I-) labeled molecules with a 15-microns spatial resolution on a 1.2 cm2 area. We have combined recent techniques (specific scintillator thin sheets and intensified charge-coupled device [CCD]) so that this imager offers a wide dynamic range and real-time acquisition. Several biological applications will be discussed.

Animals↗

PubMed1992

A new deficiency mapping technique using the SOFI detector.

We present a new technique for chromosomal deficiency mapping that takes advantage of the ability of the SOFI detector to provide fast quantitative data of very weak signals. With this new strategy, in contrast to the time-consuming traditional method, all the clones corresponding to a given genomic region may be mapped for their inclusion inside a deletion with only two hybridizations, independent of the size of the genomic region to be analyzed.

Animals↗

PubMed1991

SOFI: a bidimensional detector for fast direct on-line quantification of beta particles on blots.

We present a high-speed, high-resolution beta imager developed to replace autoradiographic films currently used in molecular biology experiments. It allows the user to locate and make quantitative analyses of 32P-labeled molecules on a 25.6 x 25.6-cm flat surface. Combining new techniques--scintillating optical fibers and multianode photomultipliers--this fast imager offers several advantages when compared with recent gas detectors and flexibility for further improvements. Several biological applications will be discussed.

Animals↗