human DNA Repeats SV40 pig nuclear-transfert rat QFISH mouse Southern-blot Cercomona mona CGA-project Bovin aging Linux  interstitial telomeric sequences Image processing MFISH Heteromorphism karyotyping immortalization Cebus capucinus resume

 Thesis,  presentations Southern blot tools
QFISH tool
Proposals, papers and unpublished stuff

The telomeres: some words
       The number of divisions that most of normal human cells is limited in-vitro. This limit is due to the extremities of the linear structure of the chromosomes found in all the eucaryotic cells, called the telomeres. The telomeres are nucleo-proteic complexes located at the very end of the eucaryotic chromosomes. In each cell, the DNA sequence of each of the 92 human telomeres is composed of hundreds to thousands repetition of a six nucleotidic base pairs TTAGGG.These motifs are recognized by specific proteins that ensure the cellular stability of the chromosomes. Due to the mechanisms of DNA replication, the replication of the telomeres is incomplete leading to a progressive loss of TTAGGG DNA motifs in absence of a specialized  enzyme : the telomerase. In human tissues, the telomerase is only expressed in a subset of normal cells at variable rates which do not always compensate the telomere shortening, the telomerase is constituvely expressed in most cancer cells. The limit of proliferatif potential of the normal cells might weight on the human longevity but also imposes constraints to the in-vitro cellular cultures. Thus the telomere length is an indicated tool to predict the proliferative capacities of cells, which had direct applications in cell therapies, cloning technologies.

Different kind of ressources regarding the biology of the telomeres are available on this site. Software to compute telomere length can be downloaded: QuantFISHmacros are a set of macro written for NIH-Image/SCION-Image to measure fluorescent FISH signals (telomeres, ....). My thesis, several presentations (some about quantitative imaging using fluorescent microscopy) as well as projects (AFM,CEA).


Thesis and other reports

Candidating at CEA
Dynamique de la longueur des telomeres au cours de la senescence et de l'immortalisation de cellules humaines.
DESS de biologie et de pharmacologie du vieillissement
In this report written in 1994, early results on intracellular telomeric heterogeneity.

Presentations under construction

Jussieu 2001
INRA 2001

Neurotech 2000

Tools for measuring the telomere length by Southern-blotting

Those tools have to be used after densitometric extraction of the telomeric smears (using NIH-Image for example). They consist in a serie of short programs (macro written in a pascal like language) for Pro-Fit 5.01 a scientific application for non-linear curve-fitting developped by quansoft.

Tools for Quantitative FISH

QuantFISH is a set of macro for NIH-Image (compatible with SCION-Image) running under MacOS (9.x , MacOS X not tested).
The aim of QuantFISH is to accelerate the extraction of measurements of fluorescent signals on metaphasic chromosomes (such telomeres) by the extensive use of keyboards shortcuts.
These macro were written to work on 12 bits TIFF images recorded on a windows/intel computer (bit depth 4096 , size 1536x1024, little endian). However the source code can be easily modified to work on any kind of TIFF image.


analyzed metaphases


CGA project
CytoGenetic Assistant is a software primilarly dedicaced to quantitavive analysis of telomeric signals on metaphasic chromosomes. CGA has been developped byADCIS , those people do make a great job. CGA 3.1.x marks a large evolution over the previous version with new modules (flatfield correction, batch processing, SQL to build chromosomes gallery, new segmentation algorithms, preview systems), an impressive evolution of the system consists in the capability to fully customize the GUI and message passing between modules. Chromosomal preparation were observed by fluorescence using alphavivid filters set by omegafilters, the image were recorded with a slow scan CCD camera (Lhésa, KAF1600).

CGA 2.x Screen Shots
 Splash   Modules  Chromosomes Spots  Colors
 Karyotyping  Measurements
CGA 3.1.x
See  candidating at CEA  for screenshots

Proposals, papers and unpublished stuffsunder construction

Chromosomes gallery
Traces Project
The traces project, is an image processing application (macros running within Aphelion) designed
to count heavy ions impacts on a plastic slide.

Project for an AFM fellowhip: study of the telomere in  telomerase engineered human primary cells Proposal                    
CytoGenetic Assistant a new Cytogenetic application dedicaced to telomeres analysis.
unpublished paper