Place du frottis cytologique à l'adolescence [Role of the PAP smear in adolescence]

The publication of the 2006 directives concerning the management of PAP smears has incited us to update our internal protocols at the CHUV, which are described in this article. A new addition to these directives is the specific management of adolescent PAP smears, who present both a high HPV carriage rate and increased incidence of cytological abnormalities with a favorable outcome in most cases. Our goal is to avoid over-treating dysplasias in this type of patient in order to avoid long-term complications. Emphasis is placed on the first gynecological consultation where a listening ear and clear and targeted information remain essential in the proper management of a young patient.

Proteomics of methylene blue photo-treated plasma before and after removal of the dye by an absorbent filter.

Methylene blue (MB) and light are used for virus inactivation of plasma for transfusion. However, the presence of MB has been the subject of concern, and efforts have been made to efficiently remove the dye after photo-treatment. For this study, plasma was collected by apheresis from 10 donors (group A), then treated using the MacoPharma THERAFLEX procedure (MB; 1 microM, and light exposure; 180 J/cm(2)) (group B), and finally filtered in order to remove the dye (group C). Proteins were analyzed by two-dimensional electrophoresis, and peptides showing modifications were characterized by mass spectrometry. Clottable and antigenic fibrinogen levels, as well as fibrin polymerization time were measured. Analyses of the gels focused on a region corresponding to pI between 4.5 and 6.5, and M(r) from 7000 to 58 000. In this area, 387 +/- 47 spots matched, and four of these spots presented significant modifications. They corresponded to changes of the gamma-chain of fibrinogen, of transthyretin, and of apolipoprotein A-I, respectively. A decrease of clottable fibrinogen and a prolongation of fibrin polymerization time were observed in groups B and C. Removal of MB by filtration was not responsible for additional protein alterations. The effect of over-treatment of plasma by very high concentrations of MB (50 microM) in association with prolonged light exposure (3 h) was also analyzed, and showed complex alterations of most of the plasma proteins, including fibrinogen gamma-chain, transthyretin, and apolipoprotein A-I. Our data indicates that MB treatment at high concentration and prolonged illumination severely injure plasma proteins. By contrast, at the MB concentration used to inactivate viruses, damages are apparently very restricted.

Removal of unusual, large high-velocity metallic maxillary sinus foreign bodies by a modified free bone flap technique.

Metallic foreign bodies are rarely found in the maxillary sinus, and usually they have a dental origin.Potential complications related to foreign bodies include recurrent sinusitis, rhinolith formation, cutaneous fistula,chemical poisoning, facial neuralgic pain and even malignancies.Two main surgical approaches are currently used for the removal of foreign bodies in the maxillary sinus: the bone flap and the endoscopic sinus techniques. We are reporting two unusual cases of large high-velocity foreign bodies removed by a modified maxillary lateral antrotomy,with free bone flap repositioning and fixation with a titanium miniplate.

Neurophysiologic and proteomic investigations of experience-dependent plasticity in the somatosensory cortex of the adult mouse following chronic whisker stimulation

RESUME Les follicules des vibrisses des rongeurs sont représentés sous la forme d'une carte topographique dans le cortex à tonneaux. Lorsque un groupe de vibrisses est coupé pendant plusieurs jours chez un rongeur adulte, en laissant les autres vibrisses intactes, le champ réceptif des neurones du cortex à tonneaux est modifié, ce qui démontre que les cartes corticales sont plastiques. Dans notre étude, une expérience sensorielle a été induite chez une souris adulte se comportant librement en stimulant chroniquement une de ses vibrisses pendant 24h. Par une analyse des potentiels de champ locaux, nous démontrons que les caractéristiques spatiotemporelles du flux d'excitation évoqué par la vibrisse principale (VP) dans la colonne corticale correspondante à la vibrisse stimulée n'est pas altéré. Par contre, l'enregistrement des potentiels d'actions d'un total de 1041 neurones à travers le cortex à tonneaux révèlent plusieurs modifications de l'activité neuronale. L'activité spontanée ainsi que la réponse évoquée par la VP sont déprimées dans la colonne corticale stimulée (nombre moyen de potentiels d'action évoqués par la VP diminue de 25 % et 36% dans la couche IV et les couches II&III). La réponse des neurones à la vibrisse stimulée diminue également dans les colonnes corticales adjacentes, «non-stimulées». La dépression de l'activité spontanée et de la réponse à la VP est localisée à la colonne corticale stimulée. Dans le tonneau stimulé, la première partie de la réponse à la VP n'est pas affaiblie, démontrant que la dépression de la réponse n'est pas due à un phénomène de plasticité sous-corticale ou thalamocorticale. La stimulation chronique d'une vibrisse entraîne une augmentation du nombre de synapses GABAergiques dans la couche IV du tonneau correspondant (Knott et al, 2002). Dès lors, nos résultats suggèrent qu'une augmentation de l'inhibition dans le tonneau stimulé serait à l'origine de la diminution des potentiels d'action évoqués par la vibrisse stimulée et en conséquence de l'amplitude du flux d'excitation vers les couches II&III puis vers les colonnes corticales adjacentes. Toutes les réponses des neurones du tonneau stimulé ne sont pas déprimées. Les réponses des neurones à la vibrisse voisine caudale à VP diminuent dans la couche IV (42%) et dans les couches II&III (52%) mais pas les réponses aux 7 autres vibrisses voisines. Les entrées synaptiques en provenance de la vibrisse caudale pourraient avoir été spécifiquement déprimées en raison d'une décorrélation prolongée entre l'activité évoquée dans les chemins sensoriels relatifs à la vibrisse stimulée et à la vibrisse caudale, spécificité qui découlerait du fait que, parmi les vibrisses voisines à la VP, la vibrisse caudale génère les réponses les plus fortes dans la colonne corticale. Quatre jours après l'arrêt de la stimulation, l'activité neuronale n'est plus déprimée; au contraire, nous observons une potentiation des réponses à la VP dans la couche IV de la colonne corticale stimulée. De plus, nous montrons que l'expression des protéines GLT-1 et GLAST, deux transporteurs astrocytaires du glutamate, est augmentée de ~2.5 fois dans la colonne corticale stimulée, indiquant l'existence d'une «plasticité gliale» et suggérant que les cellules gliales participent activement à l'adaptation du cerveau à l'expérience. ABSTRACT In the barrel cortex, mystacial whisker follicles are represented in the form of a topographie map. The selective removal of a set of whiskers while sparing others for several days in an adult rodent alters receptive field of barrel cortex neurons, demonstrating experience-dependent plasticity of cortical maps. Here sensory experience was altered by chronic stimulation of a whisker for a 24h period in a freely behaving adult mouse. By means of an evoked local field potential analysis, we show that chronic stimulation does not alter the flow of excitation evoked by the principal whisker (PW) in the stimulated barrel column. However, the recording of neuronal firing from a total of 1041 single units throughout the barrel cortex reveals several changes in neuronal activity. Immediately after chronic stimulation, spontaneous activity as well as PW-responses are depressed in the stimulated barrel column (mean number of spikes per PW-deflection decreases by 25% and 36% in layer IV and layers II&III, respectively). Neuronal responses towards the chronically stimulated whisker are also significantly depressed in layers II&III of the adjacent "non-stimulated" barrel' columns. The depression of both spontaneous activity and PW-responses are restricted to the stimulated ban-el column. The earliest time epoch of the PW-response in the stimulated barrel is not depressed, demonstrating that the decrease of cortical responses is not due to subcortical or thalamocortical plasticity. The depression of PW-response in the stimulated barrel correlates with an increase in the number of GABAergic synapses in layer IV (Knott et al., 2002). Therefore, our results suggest that an increase in inhibition within the stimulated barrel may reduce its excitatory output and accordingly the flow of excitation towards layers and the subsequent horizontal spread into adjacent barrel columns. Not all responses of neurons in the stimulated barrel are depressed. Neuronal responses towards the caudal in-row whisker decrease by 42% in layer IV and 52% in layers MM but responses to the other 7 immediate surround whiskers (SWs) are not affected. The synaptic inputs from the SW that elicit the strongest responses in the stimulated barrel may have been specifically depressed following a prolonged period of diminished coherence between neuronal activity evoked in the pathways from the chronically stimulated whisker and from its surrounding in-row whisker. Four days after the cessation of the stimulation, depression of neuronal activity is no longer present; on the contrary, we observe a small but significant potentiation of PW-responses in layer IV of the stimulated barrel column. Moreover we show that the expression of astrocytic glutamate transporters GLT-1 and GLAST proteins were both upregulated by ~2.5 fold in the stimulated barrel column, which indicates that glial cells exhibit experience-dependent functional changes and could actively take part in the adaptation of the cerebral cortex to experience.

Homonymous Ganglion Cell Layer Thinning After Isolated Occipital Lesion: Macular OCT Demonstrates Transsynaptic Retrograde Retinal Degeneration.

A 48-year-old man was examined 24 months after medial and surgical treatment of an isolated well-circumscribed right occipital lobe abscess. An asymptomatic residual left homonymous inferior scotoma was present. Fundus examination revealed temporal pallor of both optic discs, and optical coherence tomography (OCT) revealed mild temporal loss of retinal nerve fiber layer in both eyes. No relative afferent pupillary defect was present. Assessment of the retinal ganglion cell layer demonstrated homonymous thinning in a pattern corresponding to the homonymous visual field loss. There were no abnormalities of the lateral geniculate nuclei or optic tracts on review of the initial brain computed tomography and follow-up magnetic resonance imaging. We believe our patient showed evidence of transsynaptic retrograde degeneration after an isolated right occipital lobe lesion, and the homonymous neuronal loss was detected on OCT by assessing the retinal ganglion cell layer.

Proximity of excitatory synapses and astroglial gap junctions in layer IV of the mouse barrel cortex.

Neurons and astrocytes, the two major cell populations in the adult brain, are characterized by their own mode of intercellular communication--the synapses and the gap junctions (GJ), respectively. In addition, there is increasing evidence for dynamic and metabolic neuroglial interactions resulting in the modulation of synaptic transmission at the so-called "tripartite synapse". Based on this, we have investigated at the ultrastructural level how excitatory synapses (ES) and astroglial GJ are spatially distributed in layer IV of the barrel cortex of the adult mouse. We used specific antibodies for connexin (Cx) 30 and 43 to identify astroglial GJ, these two proteins are known to be present in the majority of astroglial GJ in the cerebral cortex. In electron-microscopic images, we measured the distance between two ES, between two GJ and between a GJ and its nearest ES. We found a ratio of two GJ per three ES in the hollow and septal areas. Taking into account the size of an astrocyte domain, the high density of GJ suggests the occurrence of reflexive type, i.e. GJ between processes of the same astrocyte. Interestingly, the distance between an ES and an astroglial GJ was found to be significantly lower than that between either two synapses or between two GJ. These observations indicate that the two modes of cell-to-cell communication are not randomly distributed in layer IV of the barrel cortex. Consequently, this feature may provide the morphological support for the recently reported functional interactions between neuronal circuits and astroglial networks.