L'histogenèse régénératrice chez les phoronidiens

Summary The regeneration (organogenesis was studied by Emig, 1972 a, b) of Phoronida can be divided into three phases: the first one, cicatrisation, is characterized by a provisional mesodermal scar-tissue, later the old epidermis cover this scar-tissue. The regenerating blastema, second phase, takes place by cellular dedifferentiation processes; each germ layer (ectoderm, mesoderm, endoderm) regenerates itself from its own elements. One exception only seems to be oesophagel regeneration by metaplasia of the prestomacal cells during the asexual reproduction. The differentiation of the amputated structures (third phase) appears submitted to the inductive influence of the mesoderm and to the trophic action of the nervous system (especially the epithelial plexus). The polarity in regeneration sets a problem in Phoronida.

---

---

Ce travail a été effectué dans le cadre du contrat L. A. n 41 au C. N. R. S.     

Performances diagnostiques des tomoscintigraphies myocardiques de stress,réalisées avec une caméra à semi-conducteurs et un protocole très faible dose

IntroductionThis retrospective study aimed to assess the performances in the detection of coronary artery disease patients of the stress myocardial perfusion imaging (MPI) performed with a semiconductor camera, a very low dose stress-rest protocol and short recording times.Material and methodsWe analyzed consecutive MPI exams, which has been routinely planed with the “D-SPECT” semiconductor camera, a 1-day stress-rest protocol, very low doses of Sestamibi-^99mTc (120 MBq at stress and 360 MBq at rest for a 75 kg body weight patient) and short acquisition-times targeting the recording of 500 myocardial kcounts (on average, 8 min for stress and 3 min for rest). The ability to detect coronary artery stenosis (> 50% diameter reduction) was assessed in a group of 118 patients, who had coronary angiography at ≤ 3 months from MPI, and normalcy rate was assessed in a group of 74 patients showing a low pretest probability of coronary artery disease (< 10%).ResultsSensitivity, positive predictive value and global accuracy for identifying the 81 patients with ≥ 1 coronary artery stenosis were 85%, 83% and 78%, respectively; and normalcy rate was 96%. Mean effective doses were: (1) 4.9 ± 1.4 mSv in the group with coronary angiography and where most exams (90%) comprised both stress and rest MPI; and (2) 1.9 ± 1.5 mSv in the low probability group and where most exams (70%) comprised only stress MPI.ConclusionWhen performed with a sensitive semiconductor camera and a very low dose stress-rest protocol, MPI provides high diagnostic performances, equivalent to those documented with conventional cameras in the same study setting, but with dramatic reduction of patients’ radiation.     

Une syringocèle révélée par un abcès périntéal

Purpose

The authors present a clinical report of a perforate syringocele diagnosed in a male patient and they review the clinical, radiological and therapeutic aspects of this disease.

Case report

A 50-year-old man attended the emergency room with perineal abscess. Computerized Tomography (CT) scan was used to establish the diagnosis. This patient also underwent urethrocystoscopy, sonography and retrograde urethrography.

Results

Treatment consisted of open surgical evacuation of the perineal abscess with bladder catheter. Urethrocystoscopy showed a large perforate syringocele in the urethra with no need for endoscopy marsupialization. No recurrence was observed at follow-up at 3 months.

Conclusion

Syringocele is a rare malformation which usually is asymptomatic. It can be congenital or acquired and can be classified into four morphological types. The most frequent treatment is endoscopic marsupialization of the syringocèle. Open surgical excision is recommended for complicated syringocèle with abscess or perineal pain.     

Ecologie des Dermestidae,une famille de Coléoptères nécrophages associée aux cadavres squelettisés

Lorsqu’un animal meurt, son cadavre forme un écosystème local instable et éphémère où différentes communautés d’insectes nécrophages vont se nourrir. Cette étude a pour but de caractériser les relations entre deux familles fréquentes en contextes médico-légal : les Diptères Calliphoridae et les Coléoptères Dermestidae. Des expériences de choix binaire (olfactomètres en T) et de prédation des Dermestes sur les larves de Diptères ont constitué le 1er axe de notre étude. Il en ressort que l’espèce D. maculatus (adultes et larves) n’exerce qu’une très faible prédation sur les larves de L. sericata. En absence de nourriture, les Dermestes sont néanmoins capables de prédater les pupes de L. sericata, et donc de faire disparaitre ces traces particulièrement importantes en entomologie médico-légale et en archéo-entomologie. Le second axe s’est focalisé sur les relations de compétition et d’agrégation entre D. maculatus et D. haemorrhoidalis. Les résultats obtenus n’ont pas mis en évidence de mécanismes de compétition ou d’exclusion entre ces deux espèces pourtant amenées à fréquenter simultanément le même habitat et à exploiter les mêmes ressources. Placées en condition de choix binaire (2 spots identiques), les 2 espèces s’agrègent ensemble. Mais le développement conjoint de ces 2 espèces sur une seule source de nourriture non limitante entraine une baisse significative du taux de survie chez les deux espèces. Au vu de ces résultats, nous avons conclu à la possibilité d’une coexistence de ces différentes espèces (L. sericata, D. maculatus et D. haemorrhoidalis) sur un cadavre.     

Des gènes à la culture : réflexions finales

Imagination pushes humanity well beyond its natural biological capacities. An approach of co-evolution, between molecular biology and behaviour, is thus required to explain these combined processes. Technological performances define spiritual conquests and formulas whose sole function is cultural. Humanity operates according to intentional social modes defined by the group, but these immediately become conditions for their own evolution. These choices are the motor for the history of humanity, and thus humanity can itself choose its own path. Anatomic modernisation is only a distant reflection of bipedalism, but freeing the hands leads to the development of abstract thought. The relationship between anatomy and awareness allows infinite variations in the harmonious adaptation to nature, animals and other societies. In Europe, humanity arrived in abrupt bursts because it was the result of external evolution, continuous and distant, dispersed across Asia. By its unceasing audacity, humanity combats biological determinism, imposing “moral” rules, or imperatives. The balance between biology and culture is reflected in the rules for sharing food: the biological life itself is coded by social sharing. These systems take on ternary values as soon as they include animal behaviours. Built shelters integrate societies with the cosmos because they delimit cultural spaces within natural chaos. Mastery of cognitive mechanisms gives humanity an entirely new responsibility, that of being able to define its destiny. Our united disciplines are transformed into ethical requirements.     

Modèle géométrique de l'œuf de Ver à soie

Résumé L'uf de ver à soie qui se prête à de nombreuses recherches génétiques et physiologiques a été assimilé à un volume géométrique simple afin qu'on puisse calculer aisément l'aire de sa surface totale et son volume. On a d'abord cherché à justifier le modèle géométrique proposé grâce à une étude expérimentale et statistique. On a ensuite établi les formules mathématiques utiles. Enfin on a discuté de l'approximation donnée par ces formules et de leur signification biologique.

---

Summary The egg of the silkworm which permits a lot of genetical and physiological researches has been assimilated to a simple geometric volume, so that the area of its total surface and its volume might be easily calculated. First we have tried to justify the geometrical model which is proposed by means of an experimental and statistical study. We have then demonstrated the useful mathematical formulas. Finally we have discussed the approximation given by these formulas and their biological significance.

---

Zusammenfassung Das Seidenraupenei, das viele genetische und physiologische Forschungen ermöglicht, hat man mit einem einfachen geometrischen Modell verglichen, um seine ganze Fläche und sein Volumen leicht rechnen zu können. Zuerst hat man versucht, das vorgeschlagene geometrische Modell dank einer experimentalen und statistischen Arbeit zu rechtfertigen. Dann sind die nötigen mathematischen Formeln festgesetzt worden. Zuletzt hat man die durch diese Formeln gegebenen Annäherungen und ihre biologischen Bedeutung erörtert.

---

---

Avec la collaboration technique de Mme.Donas