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.      

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.

---

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.

---

---

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

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.     

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).     

Rol del enterocito en la dislipemia de la resistencia insulínica

The increase in cardiovascular morbidity and mortality associated to insulin resistance (IR) states (obesity, metabolic syndrome, type 2 diabetes) represents a major public health problem. In IR, dyslipidemia typically include hypertriglyceridemia, low high density lipoprotein cholesterol, increased small and dense low density lipoprotein particles, and post-prandial hyperlipidemia, which play a direct or indirect role in the mecanisms of atherosclerosis. Dyslipidemia is mainly due to accumulation of circulating triglyceride-rich lipoproteins from the liver and bowel. The bowel has traditionally been seen as a passive organ, but current evidence confirms that it is an active organ subject to regulation by free fatty acids, insulin, incretins, and inflammation. Two new concepts have emerged: intestinal IR and overproduction of chylomicrons in hyperinsulinemic/IR states. A better understanding of intestinal IR may make the enterocyte a therapeutic target.     

Effets de la radiothérapie sur la fonction testiculaire de l'adulte

Radiation therapy plays a major role in the curative management of numerous neoplasms, such as Hodgkin's disease or testicular cancer. However, the adverse effects of low-dose radiation scattered to radiosensitive normal tissues adjacent to the radiation fields, such as the testes, have been recognized. Experimental studies performed on healthy volunteers showed that no lesion was detectable on sperm counts or testicular biopsies after single doses of less than 10 cGy. Oligospermia has been reported after 15 cGy and 100 cGy result in a 90% incidence of azoospermia. In the radiotherapy of cancer, fractionated regimens are used to increase the differential effect between normal and tumoral tissues. For the same dose, a fractionated radiation regimen results in a higher incidence and a longer period of azoospermia than a single dose irradiation. Fractionated doses of >50 cGy result in a 100% incidence of azoospermia. For doses up to 200 cGy, recovery occurs but normal sperm production remains uncertain. Although the recovery time can be very long (more than 10 years), there is a risk of definitive azoospermia after doses of >200 cGy. Spermatogonia are the most radio-sensitive cell type and their depletion after small irradiation doses explain the effect of radiotherapy on fertility. Clinical hypogonadism is very unfrequent in usual practice, what seems to prove a relative radio-resistance of the Leydig cells. However, functionals studies show that there is a rise in serum LH with increasing dose to the testes. A decrease in testosterone levels has been reported after high testicular doses.     

L’apport de la neuro-imagerie dans la maladie d’Alzheimer

Today, the role of neuroimaging in the diagnosis of Alzheimer’s disease (AD) extends beyond its traditional role of excluding other conditions such as neurosurgical lesions. Modern challenges for neuroimaging techniques aim to contribute to the early diagnosis of AD. Early diagnosis includes recognition of pre-demented conditions, such as people with mild cognitive impairment (MCI) or with high risk of developing AD. In addition, early diagnosis would allow early treatment using currently available therapies or new therapies in the future. In this article, we will present the modern role of neuroimaging in AD. Structural MRI can detect and follow the time course of medial temporal lobe atrophy as a surrogate marker for the pathological process. New MRI techniques and image analysis software can detect subtle brain diffusion, perfusion or metabolic changes thus providing new tools for studying the pathological process. New ligands are also available for studies using tracers and positron emission tomography.     

Influence de la lumière et de la mycosporine sur la composition stérolique du Nectria galligena au cours de la morphogenese sexuée

The nature and content of free sterols, analyzed by MIKE spectrometry, were investigated in in vitro cultures submitted to different light regimes with or without the addition of exogenous mycosporin. The sterol composition was related to varying degrees of induced sexual morphogenesis, particularly when mycosporin was added to the nutrient medium.