French Institute of Health and Medical Research

About: French Institute of Health and Medical Research is a government organization based out in Paris, France. It is known for research contribution in the topics: Population & Receptor. The organization has 109367 authors who have published 174236 publications receiving 8365503 citations.

Accelerated disappearance of ovarian follicles in mid-life: implications for forecasting menopause

Abstract: Menopause is triggered by the number of ovarian follicles falling below a threshold number and is irreversible because oogonial stem cells disappear after birth. Since it is the result of programmed disappearance of a limited store of follicles, menopause can be predicted using mathematical models based on total follicle counts at different ages. Our model shows follicle numbers decline bi-exponentially rather than as a simple exponential function of age, as had been assumed, with a first exponential rate parameter of -0.097 and a second of -0.237. The change occurred when numbers had fallen to the critical figure of 25,000 at age 37.5 years. The unexpectedly faster rate of ovarian ageing afterwards lowers the follicle population to 1000 at approximately 51 years, and was adopted as the menopausal threshold because it corresponds to the median age of menopause in the general population. Had the earlier rate persisted menopause would not be expected until 71 years. The impact of step reductions of follicle numbers on the prospective span of menstrual life was predicted by the model. A reduction by 50% before age 30 years resulted in the threshold being reached at 44 years and 0.6 year later for every subsequent year until age 37.5 years after which it is reached at 48 years. A reduction of 90% in childhood before age 14 years could result in menopause as early as 27 years, with increments of 0.6 year per year afterwards until after 37.5 years when it is expected at age 41 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Diffuse noxious inhibitory controls (DNIC). I. Effects on dorsal horn convergent neurones in the rat.

Abstract: SUMMARYSixty-eight convergent dorsal horn neurones have been recorded at the lumbar level in anaesthetized intact rats. All cells received prominent Aα and C fibre afferents and correspondingly could be activated by high and low threshold stimuli applied to the peripheral excitatory receptive field.

Cancer despite immunosurveillance: immunoselection and immunosubversion

Abstract: Numerous innate and adaptive immune effector cells and molecules participate in the recognition and destruction of cancer cells, a process that is known as cancer immunosurveillance. But cancer cells avoid such immunosurveillance through the outgrowth of poorly immunogenic tumour-cell variants (immunoselection) and through subversion of the immune system (immunosubversion). At the early stages of carcinogenesis, cell-intrinsic barriers to tumour development seem to be associated with stimulation of an active antitumour immune response, whereas overt tumour development seems to correlate with changes in the immunogenic properties of tumour cells. The permanent success of treatments for cancer might depend on using immunogenic chemotherapy to re-establish antitumour immune responses.

Nod1 responds to peptidoglycan delivered by the Helicobacter pylori cag pathogenicity island

Abstract: Epithelial cells can respond to conserved bacterial products that are internalized after either bacterial invasion or liposome treatment of cells. We report here that the noninvasive Gram-negative pathogen Helicobacter pylori was recognized by epithelial cells via Nod1, an intracellular pathogen-recognition molecule with specificity for Gram-negative peptidoglycan. Nod1 detection of H. pylori depended on the delivery of peptidoglycan to host cells by a bacterial type IV secretion system, encoded by the H. pylori cag pathogenicity island. Consistent with involvement of Nod1 in host defense, Nod1-deficient mice were more susceptible to infection by cag pathogenicity island-positive H. pylori than were wild-type mice. We propose that sensing of H. pylori by Nod1 represents a model for host recognition of noninvasive pathogens.