Phenotype of cultured fetal perivascular cells from human placenta studied by scanning electron microscopy.

The phenotype of perivascular placental cells has previously been studied using tissue sections from the fetal villi. The examination of these cells in culture by scanning electron microscopy gives us the opportunity to observe their three-dimensional phenotypes and associations outside their normal constraints. Human umbilical endothelial cells, which have a phenotype comparable to that observed in other studies, seem more flattened in culture than in their usual environment. Microvascular endothelial cells did not attain an epithelioid phenotype with close contacts between cells but formed a network of branched, elongated cells with phagocytotic activity. Some circular associations were observed when using a gelatinized matrix. Microvascular pericytes were large, flattened cells with an irregular border that pushed up nodular associations on a gelatin matrix. Chorioplacental myocytes adopted a network template comparable to that developed by microvascular endothelial cells. However, these elongated cells were thicker, without microvilli, and superficial filaments could be observed. In culture, confluent endothelial cells from the umbilical cord or microvascular pericytes associated as nodules reached a cell phenotype close to their in vivo counter-parts. This attainment of an in vivo phenotype remains questionable for chorioplacental myocytes. Microvascular endothelial cells, however, though there was sparse formation of circular associations, remained far from their in vivo phenotype.

Pathogenesis of limb and facial malformations induced by pyrimethamine in the rat.

The temporal sequence of morphological events resulting in limb and face malformations was studied in pyrimethamine (PY) treated female rats, 30 mg/kg of PY in a 10 ml/kg suspension of 0.9% NaCl were administered i.p. on days 12, 13 and 14 of gestation. Controls received only 0.9% NaCl solution. The females were killed at different stages of gestation (between 14 and 21 days). Early PY treated embryos showed mainly haematomas in the extremities and the mandibulo-maxillary areas. During the course of gestation, fewer haematomas and more malformations were observed. At term, malformations were observed in the same localisations where haematomas were previously seen.

Vascular anomalies and pyrimethamine-induced malformations in the rat.

Pyrimethamine injected into the rat on days 12, 13, and 14 of gestation induces several types of malformations, including limb and facial deformities. These malformations appear in the same location as the hemorrhages and hematomas induced by this substance. In order to visualize the extent of the vascular disorders in the affected areas, a polymerizable substance was injected intravenously into the fetus. After pyrimethamine treatment, the fetal vascular network was simplified and reorganized in a different way according to the severity of the malformations. The appearance of vascular pathology, followed by malformations in the same regions, raises the hypothesis of a vascular cause of fetal defects.

Orthostatic postural activity disorders recorded by statokinesimeter in post-concussional syndromes: oculomoter aspect.

The purpose of this paper is to emphasize the influence of the mesencephalic oculomotor system regulation on orthostatic postural regulation. The body at rest is never immobile but it swings continuosly. The amplitudes and the frequencies of body sway give an indication of the function of the different sensorimotor loops which are involved in body balance. An apparatus, the statokinesimeter, allows us to record these motions by means of displacement of the body's centre of gravity with respect to the centre of the basis. In the case of head or cervical injuries, the brain stem is often implicated giving a partial nuclear unilateral lesion of the III nucleus; double vision of a few degrees with picture separation of never more than 4 degrees occurs. A compensory deviation of the head follows. A conflict between afferents from the III, IV, VI, VII, XI and supraspinal nuclei occurs. The amplitude and the frequency of the body sway change. A form of treatment is proposed for the 'pseudo-vertigo' of post-concussional syndrome.

[Experimental hepatic encephalopathy. The effect of portocaval shunt on the evolution of the anterior hypothalamic neurosecretion in the rat (author's transl)]. / Encéphalopathie hépatique expérimentale : effet de l'anastomose porto-cave sur l'évolution de la neurosécrétion hypothalamique antérieure du rat.

The evolution of the anterior hypothalamic neurosecretion is studied in control, sham-operated and portocaval shunt rats. In sham-operated related to control rats, no modification of the anterior hypothalamic neurosecretion is observed. In portocaval shunt rats, the hypothalamic neurosecretion increases. This increase is mainly observed into the median eminence in all the portocaval shunt rats. The hypothesis according to which the modification of neurosecretory acitivity of the hypothalamic structures may be related to a discrepancy between the central monoamines is discussed.

[Correlation between the brain serotonin and the hypothalamic neuro-secretion in rat (author's transl)]. / Corrélation entre la sérotonine cérébrale et la neurosécrétion hypothalamique antérieure du rat

Parenteral administration of PCPA (200 mg/kg) induces changes in the quantitiy and the distribution of hypothalamic neurosecretion. This action appears very quickly and increases during the 48 hours following the injection. The histologic observations disclose a large accumulation of neurosecretory material in the supraoptic nuclei and in the accessory magnocellular groups of the anterior hypothalamus. In the median eminence large Herring bodies are seen. These results are to be compared to those obtained after mesencephalic raphes lesioning. The histologic alterations observed in the anterior hypothalamic level, may be due to complex disturbances involving the monoaminergic neuromediation.