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Mesenchymal stem cells (or stromal cells) have been initially characterized in bone marrow, but since, they have been identified in almost every tissue. Their multiple properties, namely differentiative capacity, production of cytokines and trophic molecules, and their immunosuppressive potential undoubtedly offer many therapeutic advantages, both for regenerative medecine or to relieve immune or inflammatory diseases. This is illustrated by the high number (> 100) of ongoing clinical trials with these cells. However, a prerequsite for their safe use in clinics is to guarantee that their production meet the good manufacturing practices, and that the final product is validated by adequate controls. It is thus quite a challenge to move from procedures defined for a research use to large scale production that fits with the national and international rules in terms of standardisation and controls. This underlines the importance of developping interacting networks between research teams, physicians and the industrial R&D departments. This fruitful collaboration will ensure the definition of appropriate and safe procedures for a successful therapeutic application., (© 2011 médecine/sciences - Inserm / SRMS.)

Fifty years after Henrietta Lacks died of aggressive glandular cervical cancer, the first cell line - HeLa cell line - is the workhorse of laboratories everywhere. It helped to produce drugs for numerous diseases, including poliomyelitis, Parkinson's, leukemias. But they are so outrageously robust that they contaminated hundred of other cell lines, as far away as Russia. For decades, biologists worked with contaminated cell lines and today, the problem is not yet solved. But the story of HeLa cells is also a moving reflection of racial and ethical issues in medicine in the late half-twentieth century in the USA.

We have tried to study the fate of Salmonella strains in soil. We have looked at their biochemical modifications during their evolution to dormant state and during their reviviscence. The beta galactosidase which is negative in the parent strain became positive after two weeks of cells starvation in soil. Stressed cells became able to produce acetoin. Some stressed cells did not produce the lysine decarboxylase, which is positive in parent cells. These modifications are reversible and depend on cultural conditions. Incubation of stressed cells in nutrient broth for more than four weeks helped them to reverse to normal forms. Simultaneous search for atypical Salmonella was done in dissect sludge of a domestic wastewater treatment plant and in soil irrigated with treated water. Atypical strains of Salmonella are found. We have seen that, after incubation in nutrient broth for more than four weeks, atypical strains characters evolved generally to their parental characters. All modifications of Salmonella in soil samples can make their identification very difficult and perhaps impossible.

The informations obtained using in vitro folliculogenesis in rodents have shown that ovulation of preantral follicles or granulosa-cumulus complexes can be obtained after a few days of in vitro culture and that live young can be obtained following fertilization and development of these oocytes. In addition, initiation of follicular growth from primordial follicles could be achieved in organ culture in vitro. Hence, when the two techniques were combined, all folliculogenesis (from the primordial stage to ovulation) could be achieved in vitro. The situation is more complex in primates/human owing to the lower number of follicles initiating growth per day and to the longer duration of folliculogenesis. A few reports suggest that preantral follicles can survive and grow in culture for a few days and one study demonstrates that in 2 months, follicles can grow from 150 microns to 1.6 mm in diameter. The short term interest of such studies is to improve our understanding of the mechanisms involved in basal folliculogenesis. In the longer term, such techniques may prove useful to maintain some reproductive potential to women submitted to total body irradiation, to improve the management of reproduction of women suffering from early menopause or to generate oocyte banks to donate oocytes.

During the last 20 years, numerous studies have been performed to improve culture conditions in order to allow in vitro growth and meiotic maturation of oocytes isolated from primordial to antral follicles. The main objective of these studies is to define optimal culture conditions which will allow to increase the recovery rate of oocytes that can be successfully fertilized. This paper reviews the more recent advances obtained when studying mouse oocyte development in vitro.