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1.
Our knowledge of gamete interaction in vitro and in vivo has grown rapidly over the last century. Its importance has been reinforced by the development of in vitro fertilization and assisted conception procedures on one hand, and by research on the development of contraceptive vaccines on the other. This literature review synthesizes our current understanding of the successive steps in the fertilization process from sperm capacitation allthrough gamete fusion, including sperm interaction with the cumulus oophorus and the zona pellucida, as well as consideration on the mechanisms and timing of the acrosome reaction.  相似文献   

2.
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.  相似文献   

3.
Abstract

La sinéfungine dont nous avons récemment achevé la synthèse (1) possède une activité antiparasitaire en particulier sur différentes souches de Leishmania (2) mais présente 1′inconvénient d'ine toxicité non négligeable; nous avons donc entrepris la synthèse d'analogues, en particulier du dérivé 9’ désamino è partir de l'adénosine et è partir du ribose.  相似文献   

4.
Cancer of the penis is rare. It often raises the issue of acceptability of the amputation of penis. We report a case of cancer of the penis following a late circumcision. The treatment consisted of amputation of two-thirds of the penis. The patient is alive without any local recurrence 2 years after surgery. Literature review suggests that this type of cancer is very rare. The factors associated with such cancer include lack of circumcision and infection with human papilloma virus.  相似文献   

5.
E. Deniau  D. Cohen 《PSN》2007,5(2):109-116
European and US drug regulatory authorities have recently warned against the use of selective serotonin reuptake inhibitors (SSRIs) in childhood and adolescent depression. Through an extensive literature review on the use of SSRIs to treat depression in children and adolescents — including psychiatric clinical trials, pharmacology, and drug safety data — we will: i) describe the main arguments justifying various regulatory decisions; ii) present published data and subsequent meta-analyses; iii) discuss how to integrate the recommendations into daily clinical practice, freeing professionals from a Manichean approach. We reach the limits of evidence-based medicine, which provide the basis of the scientific work of the regulatory authorities.  相似文献   

6.
The problem of the forms of plants and models of branching are discussed using experimental data on the mistletoe. The number of branches by division, the distribution of divisions with regard to the number of branches per division and to the level of division, the geometrical characters of branches according to the level of division and the host, the stability of model are studied. One gives an interpretation of the model of branching as a model of growth.   相似文献   

7.
The investigation of neural activity in OCD (Obsessive Compulsive Disorder) has allowed to link obsessive compulsive symptoms and cortico-striatal dysfunction. In the present article, we try to show the significance of cognition in an integrative physiopathologic model of OCD. Clinically, patients are unable to inhibit irrelevant thoughts or actions. In a cognitive way, decision making, planification or organisation are impaired. Those impairments are related to an executive deficit, which depends on frontal structures. Finally, we present a current study which tries to identify executive deficit functions related to cerebral dysfunction in patients presenting different OCD features (washing, checking, hoarding).  相似文献   

8.
《L'Anthropologie》2022,126(3):103050
The birth of agriculture east of the Fertile Crescent, between the Iranian plateau, Central Asia and South Asia, is poorly known. This area is vast and the archaeological data relating to this period, the Neolithic, is extremely limited. Most researchers agree that plants and animals’ domestication was introduced in this area from south-west Asia, similarly to what happened in Europe. In this scenario, agriculture emerged in the Fertile Crescent, between the Levant, Anatolia and the Zagros, 12.000 to 11.000 years ago, and then spread to other regions further east, across the Iranian plateau to Central Asia and the north-western part of the Indian subcontinent, beginning between the 8th and 7th millennia BCE. This article summarizes the main available data relating to this topic with a focus on the Indo-Iranian Borderlands, between southeastern Iran and Pakistan. Currently available paleoclimatic, paleogenetic and archaeological records are presented. A synthesis and discussion is then provided in the conclusion as well as reconstructions based on these records. Issues or challenges relating to the research on the earliest farming villages are mentioned while directions for future research are evoked.  相似文献   

9.
10.
Nicolas Franck 《PSN》2004,2(1):10-25
Theoretical models about action monitoring and action attribution developed over the last ten years have given a new framework in the understanding of first-rank symptoms of schizophrenia, as described by Kurt Schneider. Impaired action attribution has been demonstrated in patients with first-rank symptoms. Moreover, positron emission tomography studies have revealed that the cortical network involved in action attribution processes in normal subjects is not correctly activated in patients with first-rank symptoms. These results demonstrate that these symptoms are related to cognitive and cerebral correlates and they shed new light on the understanding of psychotic symptoms.  相似文献   

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Many parameters can affect the patient's dose and the CT image quality. It is therefore essential, in order to optimize the patient's dosimetry, to know the influence of these parameters as well as their link with the dose modulation tools.  相似文献   

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14.
Despite surgical treatment, cryptorchidism is the most common cause of infertility. Through a literature review, the authors report current data on the influence of age at the time of orchidopexy, testicular size, the position of the testis, and the existence of epididymal anomalies on fertility.  相似文献   

15.
《L'Anthropologie》2018,122(2):183-219
Opening towards the eastern steppe landmass, the Eastern Romania area covers 87,500 km2, and shelters the biggest number of Gravettian and Epigravettian sites currently known. Archaeological researches in the area expanded in the 1950's, during the construction of dams on the Prut and Bistrița valleys. The efforts of the multidisciplinary teams involved and the subsequently published papers highlighted the archaeological potential of the region and, with some inevitable interruptions, investigations continued to this day. Although the time and resources spent were not modest, the outcomes regarding the Upper Palaeolithic cultural sequence often proved contradictory and somehow distant from the general European cultural dynamic. Thus, this reassessment tries to put the chronological, palaeoenvironmental, and empirical data in a more coherent framework. A synthesis of the available Gravettian and Epigravettian data east of the Carpathians reveals the following sequence: (1) an Aurignacian stage on the Prut Valley, paralleled by an indefinite Upper Palaeolithic stage, from sites on the Bistrița Valley, between 31 and 28 ka (uncal BP); (2) a quite early Gravettian presence, roughly between 27 and 25.5 ka, which includes backed laminar blanks, schematic decoration of one pendant, and the use of perforated shells as adornments; (3) a scant shouldered points stage, chronologically close to the European similar phases (25–23 ka), for which the feeble use of obsidian points toward contacts with Central European resources/populations; (4) a Gravettian/Epigravettian interface, between 21 and 19 ka, manifested within numerous archaeological layers, mainly through an increase in bladelets and organic artefacts production/use; (5) an Epigravettian stage, between 18 and 16 ka, largely defined through an upturn in raw material choices, backed implements production, and tool types; (6) one last, roughly 14 ka old Epigravettian stage, in which the technological choices recalled those of the previous one. Regional variability elements and radiocarbon chronology limitations considered, apparently, the Gravettian and the Epigravettian of Eastern Romania share quite a lot of traits with the corresponding Central and Eastern European technocomplexes.  相似文献   

16.
J. Auger 《Andrologie》1997,7(4):433-442
Several studies have shown a good correlation between sperm motility and fertility though the microscopic evaluation of the percentage of motile sperm is highly subjective by nature. Therefore in the last decade, various objectives methods have been proposed to overcome this problem. Two types of methods were developed: The methods based on the analysis of images obtained by microphotography, microcinematography and microvideography and the global, undirect methods based on physical principles. Several systems based on video and image analysis (Computer Aided Sperm Analysis, CASA) have been developed and are used in numerous laboratories of reproductive biology. CASA technology offers the possibility to analyse some characteristics of sperm motion which are related to the fertilization potential and to develop new parameters related to some important aspects of sperm behavior such as hyperactivation. However, there is a large amount of interactions between the operator and the CASA machine. CASA instruments are not “ready-to-use” robots: the reliability of CASA depends largely on the expertise and training of the user and the application of standardized procedures and quality control schemes. By contrast, there is only minimal interaction between the operator and the Sperm Quality Anlyser which is a new device measuring and index of sperm motility highly correlated to the concentration of progressively motile sperm. The device uses light passed through a small sample of semen introduced in a capillary tube to detect variations in optical density that result from moving particles. The reproducibility of the measurements is excellent, the device is easy to use and this is a potentially useful tool for field-work studies. Further investigations of this device in the managment of male infertility is warranted. Finally, both types of objectives approaches are complementary to the conventional analysis of sperm motility and they will not replace it. Standardized procedures have been proposed by the World Health Organization for the subjective evaluation of sperm motility. Such procedures are very useful to reduce significantly the intra- and interlaboratory variations but internal and external quality controls schemes indicate that they are not sufficient to achieve acceptable levels of variation and regular quality controls followed by the definition and the application of corrective procedures are required.  相似文献   

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19.
《Médecine Nucléaire》2007,31(11):610-612
Coronary angiography often remains an unavoidable gold standard in cardiology practice for determining the severity, extent and prognosis of coronary artery disease and for therapeutic decision making, although established non-invasive testing – such as myocardial perfusion imaging or stress echocardiography – have demonstrated their diagnostic value and their incremental pronostic value over coronary angiography. Newer noninvasive techniques, such as multidetector computed tomography and magnetic resonance imaging, are currently being validated and will very soon be considered as alternatives to these imaging modalities in clinical practice. Facing this wide choice of tests, the cardiology community has the difficult task to determine the role and place of these various investigating techniques and to evaluate their resource implications, in other words, to optimize the cost-efficacy and ratios in the management of coronary artery disease.  相似文献   

20.
Osteochondritis, or Legg-Calvé-Perthes disease (LCP), is a necrosis of the proximal femoral epiphysis. This vascular accident entails on the complex phenomenon of growth of the child's hip and can result in deformations or even a strict destruction of the proximal femoral epiphysis. The aim of this article is to show the interest of the bone scintigraphy (BS) in precocious diagnosis and follow-up of LCP disease. In this aim, we introduced a clinical case of LCP disease where BS allowed a precocious diagnosis and a strigent monitoring. Discussion of case includes a systematic review of literature.  相似文献   

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