Fixation extraosseuse du radiotraceur lors de la réalisation d’une scintigraphie du squelette chez un patient atteint de bêta-thalassémie : à propos d’un cas

Red blood cell transfusion, main therapeutic modality of beta-thalassemia, leads to iron overload which may perturb several metabolic ways. The aim of this paper is to illustrate the uptake abnormalities observed on bone scan of thalassemic patients and to discuss mechanisms of extraosseous accumulation of the radiopharmaceutical in this pathology. We report a 16-year-old child suffering from beta-thalassemia major undergoing transfusion therapy. A bone scan was indicated to look for osseous infection. This study revealed a little skeletal uptake and abnormal liver, splenic and renal accumulation. A repeat bone scan, performed three weeks later showed a better skeletal uptake which enabled the discovery of focal abnormalities and made the diagnostic easier. The effect of iron overload on radiopharmaceuticals's uptake in bone scan is known since 1975. Dissociation of ^99mTc from the carrier ligand due to the presence of iron excess seems the most plausible hypothesis. Free ^99mTc can be bound to other tissular substrates which can explain extraosseous uptake. The normally available pool for bone is reduced and then the skeletal uptake decreased. This report limits considerably the sensitivity of the bone scan. A well-led iron chelation and eventually the use of diuretic drug may guarantee a better quality of bone scan images.     

Observations sur un pigment de membrane chez phycomyces

Sans résumé     

Microsporie observee chez un groupe de lions en capivite

Sans résumé

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Tinea microsporina observed in a group of lions in captivityEpidemic focus caused byMicrosporum lanosum

     

Coexistence chez un même patient de la maladie des légionnaires et de la fièvre Q.

A case of Legionnaires'' disease associated with Q fever is presented; this is probably the first reported case of concomitant infections with Legionella pneumophila and Coxiella burnetii. The pulmonary features of the illness were not typical of either disease. The difficulties of making a diagnosis in such cases are discussed.     

Etude de l'ecometabolisme du mercure dans un milieu d'eau douce

Resume L'étude des transformations du mercure dans l'eau et les sédiments d'une rivière est entreprise selon un mode d'approche qui semble pouvoir être généralisé pour de nombreux problème d'écologie chimique.Il consiste en l'utilisation de deux paramètres physicochimiques pour caractériser le milieu du point de vue chimique (l'utilisation de diagramme Eh–pH permettant de prévoir le comportement chimique d'un élément dans le milieu étudié) et du point de vue biologique (le Eh et le pH permettant de caractériser de façon biologiquement significative les conditions dans lesquelles sont testées les capacités de transformation des communautés bactériennes).Il est montré que le comportement du mercure, après son accumulátion sous forme peu soluble dans les sédiments, dépend d'une balance entre la formation microbiologique de méthylmercure, beaucoup plus toxique que le mercure minéral, et la minéralisation de ce méthylmercure par action microbiologique ou par un processus chimique en présence de sulfure.Stagiaire de recherche au Fonds National Belge de la Recherche Scientifique.     

Etude histologique et ultrastructurale de la granulosa à certains stades de développement du follicule ovarien chez un Lézard: Lacerta vivipara Jacquin

Résumé La granulosa s'épaissit, sans apport extérieur de cellules, par division mitotique de petites cellules folliculaires. Les cellules piriformes proviennent de la transformation de certaines petites cellules, mais elles présentent de nombreuses ressemblances morphologiques et cytologiques avec de jeunes ovocytes. A l'exception de ces similitudes aucun autre argument ne permet actuellement d'attribuer une nature germinale initiale aux cellules piriformes. Le nucléole de ces cellules montre quelques particularités et une séparation nette entre ses constituants fibrillaire et granulaire. Le rôle physiologique des cellules piriformes reste à préciser, mais elles ne possèdent pas de canal et leur appareil de Golgi très développé n'a pas de rapport avec la production des granules incorporés par l'ovocyte. La dégénérescence de nombreuses cellules piriformes, dont certains aspects ultrastructuraux sont décrits, est une des causes de la réduction de la granulosa.

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Histological and ultrastructural study of the granulosa during certain developmental stages of the ovarian follicle of a lizard, Lacerta vivipara Jacquin

Summary The granulosa thickens by mitotic division of the small follicle cells, without any external contribution. The pyriform cells arise from the transformation of certain small cells and show many morphological and cytological similarities with young oocytes. In spite of this resemblance, there is no proof for the germinal nature of the pyriform cells. The nucleolus of these cells shows certain peculiarities, and a clear separation of fibrillar and granular components. The physiological significance of the pyriform cells remains to be determined, but they have no duct and their large Golgi apparatus has no relationship with the granules incorporated by the oocyte. The degeneration of many pyriform cells is one of the reasons for the reduction of the granulosa. Some ultrastructural features of this degenerative process are described.

Avec la collaboration technique de Mme M. Hubert.     

Exemples de tératologie chez les Chitinozoaires du Pridoli de Libye et implications sur la signification biologique du groupe

Jaglin, J.-C. & Paris, F. 1992 04 IS: Exemples de tératologie chez les Chitinozoaires du Pridoli de Libye et implications sur la signification biologique du groupe. [Teratologic cases among Pridolian chitinozoans from Libya and implications on the biological interpretation of the group.] Lethaia , Vol. 25, pp. 151–164. Oslo. ISSN 0024–1164.
Fairly numerous chitinozoans displaying morphological anomalies are recorded in Late Silurian subsurface material from Western Libya. The individuals described and illustrated in our paper range exclusively in a short interval at the top of the investigated sequence. These abnormal vesicles are interpreted as teratologic cases related lo an event of unknown origin. From our conclusions, the hypothesis of vegetative reproduction stages stated by previous authors seems unlikely. Therefore we still interpret the chitinozoan vesicles as eggs (or to a lesser extent as spores) of marine organisms. * Libya, Chitinozoans, Silurian, teratology, chitinozoan affinities .     

Etude de l’erection chez le rat: un nouveau modele physiologique

Penile erection is a muscular and vascular event mediated by the autonomic nervous system. The neurophysiology of erection remains poorly understood and controversial, requiring a suitable model for in-vitro studies of erectile function. Such a model, based in the rat whose penile innervation is very similar to man, is described here. The first study using this model considers the influence of systemic blodd pressure (BP) on penile erection. In 33 anaesthetized rats the pelvic and cavernosal nerves were identified and dissected. Supra maximal electrical stimulation was delivered over 1 minute by a train of 1 ms pulses onto the pelvic nerve (10 V, 15 Hz) or the cavernosal nerve (6 V, 10 Hz). Systemic blood pressure and intracavernosal pressure (ICP) were monitored and stored on a computer. As in previous animal models (dog, monkey), four phases of the cavernosal response to neural electrical stimulation were observed: latency, tumescence, full erection, and détumescence. In all rats electrical stimulation of either the pelvic or cavernosal nerves significantly increased intracavernosal pressure. Complete erectile response (rigidity and unfolding of the penis) was only seen with intracavernosal pressures > 95 mm Hg. Intracavernosal pressure increased proportionally with blood preessure during the full erection phase according to the equation ICP=0.94 BP ? 31 mm Hg (r=0.94 BP ? 31 mm Hg (r=0.94) for electrical stimulation of the cavernosal nerve, or the alternative aquation ICP=0.76 BP ? 21 mm Hg (r=0.73) for electrical stimulation of the pelvic nerve. The rat is a readily available model for the study of erection and present obvious advantages over existing models such as the dog, cat and monkey. Cavernosal repsonse to neural stimulation was closely related to arterial blood pressure and the two linear equations presented above should be considered further in studies modifying autonomic neurotransmission as well as in relation to the effects of pharmacological compounds with vasomotor actions on erectile function.