Introduction historique et critique à la notion de dépression en psychiatrie

The author describes the history of the concept of depression in modern psychiatry from the end of the Age of Enlightenment until today in three parts. In the first period (1793–1854), the opposition of general delusion (mania) and partial delusion (melancholia) prevails, without the problem of changes of the affective state being an issue. Only with the work of J. Guislain, and later of W. Griesinger, does the concept of mood disorders become a categorical form in mental pathology with the idea of psychological pain. The second period (1854–1926) is distinguished firstly by the works of J.P. Falret on circular insanity, and then those of V. Magnan, J. Ségnan, J. Séglas et Ph. Chaslin in France and E. Kraepelin in Germany. This period is characterized by the classical construction of periodic manicdepressive psychosis and takes into account the opposition of mania and melancholia. In the third period (1926–1977), the influences of phenomenology, psychoanalysis and structuralism predominate. Gradually melancholia loses its place at the core of this field, in favour of the concept of depression and this change now characterizes contemporary psychiatry.     

Molecular Dynamics Simulations of PIP2 and PIP3 in Lipid Bilayers: Determination of Ring Orientation, and the Effects of Surface Roughness on a Poisson-Boltzmann Description

Molecular dynamics (MD) simulations of phosphatidylinositol (4,5)-bisphosphate (PIP₂) and phosphatidylinositol (3,4,5)-trisphosphate (PIP₃) in 1-palmitoyl 2-oleoyl phosphatidylcholine (POPC) bilayers indicate that the inositol rings are tilted ∼40° with respect to the bilayer surface, as compared with 17° for the P-N vector of POPC. Multiple minima were obtained for the ring twist (analogous to roll for an airplane). The phosphates at position 1 of PIP₂ and PIP₃ are within an Ångström of the plane formed by the phosphates of POPC; lipids in the surrounding shell are depressed by 0.5-0.8 Å, but otherwise the phosphoinositides do not substantially perturb the bilayer. Finite size artifacts for ion distributions are apparent for systems of ∼26 waters/lipid, but, based on simulations with a fourfold increase of the aqueous phase, the phosphoinositide positions and orientations do not show significant size effects. Electrostatic potentials evaluated from Poisson-Boltzmann (PB) calculations show a strong dependence of potential height and ring orientation, with the maxima on the −25 mV surfaces (17.1 ± 0.1 Å for PIP₂ and 19.4 ± 0.3 Å for PIP₃) occurring near the most populated orientations from MD. These surfaces are well above the background height of 10 Å estimated for negatively charged cell membranes, as would be expected for lipids involved in cellular signaling. PB calculations on microscopically flat bilayers yield similar maxima as the MD-based (microscopically rough) systems, but show less fine structure and do not clearly indicate the most probable regions. Electrostatic free energies of interaction with pentalysine are also similar for the rough and flat systems. These results support the utility of a rigid/flat bilayer model for PB-based studies of PIP₂ and PIP₃ as long as the orientations are judiciously chosen.     

The development of anoxia following occlusion

Following arteriolar occlusion, tissue oxygen concentration decreases and anoxic tissue eventually develops. Although anoxia first appears in the region most distal to the capillary at the venous end, it eventually spreads throughout the entire region of supply. In this paper the changing oxygen concentration, from the time of occlusion until the tissue is entirely anoxic, is examined mathematically. The equations governing oxygen transport to tissue are solved by iterating a nonlinear integral equation. This solution is valid until anoxia first appears. After anoxia develops it is necessary to solve a moving boundary problem. This is done using the method of matched asymptotic expansions, and accurate solutions are obtained for a wide range of physiological conditions.     

Boring Forminifera in French Polynesian coral reefs

The discovery of epipsammitic Foraminifera in sediments of Moorea and Scilly (French Polynesia) and the study of close relationships between embedded specimens and host-grains indicate that some species participate in the weakening and subsequent breakdown of skeletal grains and consequently contribute to the production of silt-sized particles. The study of 36 stations around the islands shows the factors that control the distribution and abundance of this incrusted microfauna. Specimens are more abundant on sand particles larger than 1,000 microns and in the high energy areas; this abundance decreases with depth. The physiological mechanism of penetrations is presumably chemical, but each species apparently has its own process: complete dissolution with removal of ions for the cytoplasm of calcareous species; partial dissolution with transport of silt-size aggregates on the test of agglutinated species. The purpose of such penetration may be to protect themselves against water turbulence and to provide material for test construction.     

Molecular heterogeneity of D-end products detected by anti-H-2.28 sera

Immunoprecipitation of NP-40 lysates of 125I-labeled lymph-node cells with different anti-H-2 sera and with anti-Qa-2 serum has shown that the BALB/cByA strain (H-2d, Qa-2-negative) expresses, besides H-2Ld, another molecule that is not detectable in the BALB/c-H-2dm2 strain. Electrophoresis in SDS polyacrylamide gels indicated that this molecule, provisionally designated Lq, has an apparent molecular weight of 41000 daltons, in contrast to approximately 49000 daltons for H-2Kd and H-2Ld, and 47000 daltons for H-2Dd molecules. The anti-Qa-2 serum precipitated from the Qa-2-positive strains BALB/cHeA but not from the Qa-2-negative strains BALB/cByA and BALB/c-H-2dm2 a protein that gave a very strong band corresponding to the molecular weight 41000 daltons in the gel electrophoresis. The biochemical characteristics of the Lq molecule are thus more similar to those of Qa-2 than of H-2 antigens.     

Failure of testicular development associated with a rearrangement of 9p24.1 proximal to the SNF2 gene

In 46,XY individuals, testes are determined by the activity of the SRY gene (sex-determining region Y), located on the short arm of the Ychromosome. The other genetic components of the cascade that leads to testis formation are unknown and may be located on the Xchromosome or on the autosomes. Evidence for the existence of several loci associated with failure of male sexual development is indicated by reports of 46,XY gonadal dysgenesis associated with structural abnormalities of the Xchromosome or of autosomes (chromosomes9, 10, 11 and 17). In this report, we describe the investigation of a child presenting with multiple congenital abnormalities, mental retardation and partial testicular failure. The patient had a homogeneous de novo 46,XY,inv dup(9)(pter→p24.1::p21.1 →p23.3::p24.1→qter) chromosome complement. No deletion was found by either cytogenetic or molecular analysis. The SRY gene and DSS region showed no abnormalities. Southern blotting dosage analysis with 9p probes and fluorescent in situ hybridisation data indicated that the distal breakpoint of the duplicated fragment was located at 9p24.1, proximal to the SNF2 gene. We therefore suggest that a gene involved in normal testicular development and/or maintenance is present at this position on chromosome 9. Received: 20 January 1997 / Accepted: 5 November 1997