Évolution de la cellule normale à la cellule cancéreuse prostatique hormonodépendante–hormono-indépendante

The prostatic gland is androgen-dependent. The role of androgens in the development, function and pathology of the prostatic gland (benign hypertrophy or cancer) derives from: direct evidence, resulting from experimental models (in vitro–in vivo) or from the biological analysis of normal and pathological human prostatic tissues. These data make it possible to describe the current point of our knowledge concerning the molecular, cellular, and tissular mechanisms involved; indirect data resulting from epidemiologic and clinical studies describing the impact of androgen suppression or supplementation on the prostatic gland. At the experimental level, it is generally allowed that the growth of prostate is controlled by androgens (testosterone and its metabolites). A suitable circulating testosterone level is necessary to maintain the growth, development, differentiation and function of the prostatic gland. Bilateral orchidectomy induces programmed cellular death (apoptosis) and the gland involution; exogenic testosterone administration is then able to induce the prostatic growth up to the normal level. The same applies when an impubescent animal is treated. The response of prostate to exogenic testosterone thus does not produce a growth beyond the normal volume, which is maintained by balance between proliferation and cellular death in the presence of physiological levels of androgens. The study of the mechanisms of regulation of the prostatic growth provides a fundamental justification to the chemical and hormonal treatments used by the urologists in the treatment of prostate benign hypertophy and cancer. Within the framework of the androgenic deficit related to age, a doubt persists about a potentially harmful action of the substitute androgenic treatment on prostate.     

L'acide ascorbique ou vitamine C dans la cellule et sa détection

Résumé La répartition si générale de l'acide ascorbique dans tous les éléments végétaux et animaux semble indiquer que ce corps joue un rôle général et fondamental. Mais cette répartition n'est pas homogène. Elle varie beaucoup avec les organes. Sa concentration si élective dans certaines cellules parait correspondre à des propriétés fonctionnelles communes à tous ces éléments.Histochimiquement on peut déceler l'acide ascorbique jusque dans la cellule où sa présence se localise au cytoplasma ou même à certains de ses organites: chondriome, appareil de Golgi.Sa mise en évidence y dépend de divers facteurs et en particulier de la présence d'autres substances qui bloquent son pouvoir réducteur: ce dernier fait n'est peut être pas sans importance physiologique.     

Rôle du changement de conformation du CD4 lors de la fusion VIH/cellule

It is well known that the gp120-gp41 complex undergoes a conformational change after CD4 binding. It is likely that CD4 undergoes a conformational change as well. Recently, a calculation of the normal modes of the two N-terminal domains of CD4 has shown that a hinge-bending motion of one of these domains with respect to the other may occur. In the present study, results obtained previously are verified with two other normal mode calculations, starting from crystallographic structures of different origin. A scheme describing the first steps of the process leading to cell infection by human immunodeficiency virus (HIV) is then proposed. It rests upon the idea that CD4 and gp120-gp41 conformational changes allow for bringing the cell and virus membranes closer to each other.     

Le comportement de la cellule végétale en présence de toxiques additionnés de substances tensio-actives

Résumé Le présent travail expose quelles sont les réactions de la cellule végétale lorsque cette dernière est soumise à l'association d'un toxique et d'un « mouillant » (Netzmittel).Les variables sont: la nature de la cellule végétale, celle du toxique et celle du mouillant.Alors que les mouillants cationiques, eux-mêmes toxiques, exercent une simple action additive, les mouillants anioniques révèlent dans de nombreux cas une synergie de toxicité. Celle-ci se manifeste surtout avec les champignons et les bactéries Gram+, les végétaux supérieurs se montrant indifférents. Cette synergie varie également avec la structure moléculaire du mouillant.Les mouillants non ioniques peuvent au contraire exercer une action antagoniste, c'est-à-dire diminuer la toxicité.Ce dernier phénomène se produit dans certains cas à la suite d'une réaction chimique entre le mouillant et le toxique; la nature de la cellule est alors indifférente. Dans d'autres cas, il y a absence de réaction chimique et le phénomène ne se produit qu'avec certains types de cellules (champignons surtout).La nature chimique du toxique joue, dans la synergie, un rôle moins important que dans l'antagonisme.Des hypothèses sont formulées pour tenter d'élucider le mécanisme des cas de synergie et d'antagonisme.     

Sulle cosidette „cellule parafollicolari“ nella tiroide della cavia

Zusammenfassung In der Schilddrüse der normalen und reifen Meerschweinchen sind keine unabhängigen Zellen vorhanden, die besondere Merkmale im Ver gleich zu anderen parenchymalen Zellen vorstellen. Die bis jetzt geschilderten klaren und protoplasmareichen Zellen sind in der Tat follikuläre Zellen, die in ihrer innigen Struktur modifiziert sind und die in den Schnitten wegen besonderer Verhältnisse zu dem Bindegewebe und den Gefäßen abgesondert erscheinen. Ihre strukturalen Veränderungen stehen überwiegend in engem Zusammenhang mit der Funktion, die sie bei besonderen funktionellen Beschaffenheiten der Drüse erfüllen sollen.     

Relations entre la tolérance ou la sensibilité à la salinité lors de la germination des semences et les composantes de la nutrition en sodium

Adsorption, absorption and translocation of sodium were compared in three species showing an ascending degree in tolerance to salinity: red cabbage (tolerant) shows higher Root Cationic Exchange Capacity than tomato (sensitive) or radish (intermediate). At low NaCl concentrations, tomato accumulates the greatest quantities of sodium; but Na⁺ translocation remains proportional to the quantity absorbed in the three plants. At high salt concentrations, diffusive phenomena explain similar accumulation in every plant, but red cabbage quickly localises 50% of Na⁺ amount in cotyledons, while this element stays stored in tomato roots. The consequence of these three nutrition phases was discussed in relation to the behaviour observed at the germination time of these same plants.      

L’effet des rayons x sur le protoplasme,le noyau et le chondriome de la cellule végétale d'après les observations sur le vivant

Sans résumé Avec planches I et II     

Conséquences de la chimiothérapie anticancéreuse sur la fertilité de la femme

Sterility is a potential toxic effect of chemotherapy. This risk is well established for alkylating agents, but is less clearly defined for anthracyclines, methotrexate and fluorouracil and poorly defined for alkaloids, platinum, etoposide and taxanes. The main predictive factors for ovarian toxicity are the additive effect of cytotoxic drugs, the cumulative dose of each drug and the patient’s age. This effect of chemotherapy is evaluated on menstrual cycles, hormonal assays and the number of pregnancies observed in patient cohorts. Chemotherapy induces destruction of oocytes and granulosa cells. In mice, it has been shown that adriamycin may induce oocyte apoptosis, which can be prevented by modulation of cycle cell signalling (dysregulation of Bax gene or, on the contrary, expression of its antagonist gene Bcl-2 or inhibition of apoptosis with sphingosine-1-phosphate or caspase inhibitors). Clinical data in the literature are usually based on retrospective studies and are somewhat confused: global fertility after MOPP chemotherapy for Hodgkin’s disease is about 20%, adjuvant chemotherapy with CMF, F(A)C or TAC for breast cancer induces amenorrhea in 50% to 70% of cases, PVB or BEP chemotherapy for ovarian germ cell tumors has little effect on fertility when the uterus and one ovary can be preserved, and the majority of women treated with methotrexate, actinomycin D or various combinations for persistent trophoblastic disease remain fertile. Preservation of fertility is a major goal for cancer patients receiving chemotherapy: in vitro fertilization could preserve the couple’s fertility, but is usually not feasible as it would delay initiation of chemotherapy until after stimulation of ovulation; oocyte or ovarian tissue cryopreservation is at the stage of research; oral contraceptives have not been demonstrated to be effective to preserve ovarian function; gonadotropin releasing hormone (GnRH) agonists prevent cyclophosphamide toxicity in rat and monkey ovaries, and a few pilot clinical studies suggest that chemotherapy-induced amenorrhea could be prevented by administration of GnRH analogues simultaneously to chemotherapy, but randomised studies are necessary.     

Cancer de la prostate : la maladie localisée

Localized prostate cancer is characterized by a tumor confined to the prostate gland at clinical evaluation. Since the onset of PSA screening, the detection of localized prostate cancer has increased. Prognosis factors are clinical stadification, PSA value, PSA doubling time, tumor volume related to needle biopsy pathologic findings (Gleason score, percentage biopsies involved). Treatment depends on tumor prognosis, symptoms and performance status of the patient. Localized prostate cancer can be treated by surgery (radical prostatectomy, high intensity focused ultrasound) or radiotherapy (conformational radiation therapy, brachytherapy). Active follow-up can be proposed to very low risk patients.     

De la m��ditation bouddhiste �� la th��rapie cognitive fond��e sur la pleine conscience

For the general public, Buddhist meditation has been a very fashionable subject for several years. It is presented either as a spiritual way to personal fulfilment or as a quick and effective relaxation technique. Otherwise, we have to keep in mind that Buddhist meditation is a lifestyle, born 2,500 years ago, integrated into a complex philosophic, religious, spiritual, and cultural system of thoughts. Moreover, it directly inspired the third cognitive wave of the cognitive and behavioural therapy, from which Mindfulness-Based Cognitive therapy (MBCT) was derived. The MBCT program is intended to prevent relapse/recurrence in major depression and has been the object of clinical trials with the aim of evaluating it using a scientific basis, but other indications are developed.     

Recherches sur la conservation du virus de la densonucléose

Résumé Le virus de la densonucléose (VDN) conserve une partie de sa virulence en solution aqueuse entre 0°C et 30°C pendant deux mois. Son pouvoir infectieux se maintient à—10°C pendant deux mois mais est supprimé après dix jours de dessication. On peut done considérer ceParvovirus d’Insectes comme un virus relativement résistant aux températures que l’on rencontre ordinairement dans la nature et au laboratoire.

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Summary The persistence of DNV is described. This virus retains a part of its infectivity in aqueous solution between 0°C and 30°C. The log LD₅₀ initially 7,15 drops to 2 after two months. The virus keeps its infectivity at 10°C but it loses all its pathogenicity after 10 days in dry conditions.

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Ce travail a été réalisé en partie dans le cadre d’une convention I.N.R.A.-D.R.M.E.     

Apports de la palynologie a la connaissance du Pliocène du Roussillon (sud de la France)

The present study illustrates clearly how pollen analysis may be applied to stratigraphy from a botanical point of view. Within a chronologically reliable frame (Middle Pliocene for the marine deposits on the basis of Foraminifera record; two subzones for continental deposits on the basis of Mammals record: Hautimagne for Terrats fauna, Sète for Serrat-d'en-Vacquer fauna), palynology provides a good stratigraphical boundary: the extinction of the Taxodiaceae. In a remblayage area, it is established that a continental level is not necessarily younger than a marine one unless they are superposed. Many profiles are replaced according to the «progradation of the pliocene gulf of Roussillon. The boundary between marine and continental deposits cuts through the chronological line of the Taxodiaceae extinction. The flora investigated (93 taxa) is the first known for the Pliocene of this area. The extinction of the Taxodiaceae in southern France has a climatic cause: the setting in of a mediterranean rhythm (dry summers). This extinction is much older than the one which took place in Italy (Tiberian boundary) and in the Netherlands (Reuverian-Pretiglian boundary).     

Comprendre la dépression : apport de la psychologie évolutionniste

Darwinian medicine considers that many symptoms are the organism’s defence mechanisms and adaptations that have been inherited and shaped by natural selection. But in many cases, signs and symptoms of disease are of no benefit to human survival and are in fact deregulations of normal mechanisms. Evolutionary explanations help us understand how some human affective and emotional processes could have an adaptive value and enable us to cope with a wide spectrum of situations. But the wide range of intensity levels and different forms, ranging from low moods to major depression with psychotic features, suggest that these symptoms cannot always be explained by adaptation: where is the cut-off point? In this paper, we describe the evolutionary concepts related to adaptation as applied to the emotions, particularly focusing on low mood and depression, and discuss their possible functional and adaptive role.