Na*-independent binding of [3H] muscimol to a membrane fraction of the brains of normal and dwarf mice

Summary Although their body weights were decreased by about 77% and their brain weights by about 30%, high-affinity [³H] muscimol binding to a cerebral membrane fraction was not altered in hereditary pituitary dwarf mice. Marked changes in the level of pituitary growth-associated hormones do not appear to be associated with a change in cerebral GABA-receptors.Supported by a UNESCO/IBRO Fellowship. Permanent address: Semmelweis University Medical School, 1st Institute of Biochemistry, Budapest, Hungary.     

Preferential neurotoxicity of pentobarbital on nerve and glial cells in culture

The effect of pentobarbital was studied in a mixed population of nerve and glial cells dissociated from brains of 7-day chick embryos and maintained in culture. Pentobarbital-Na was added in various concentrations ranging from 5 X 10(-5) M to 1 X 10(-3) M. The neuronal density was monitored by counting the neurons, neuronal identity was established by staining for Nissl Bodies and acetylcholinesterase. Over a culture period of 3 weeks, it was found that the barbiturate exerts a preferential dose-dependent cytotoxic effect on neurons.     

Preferential neurotoxicity of pentobarbital on nerve and glial cells in culture

Summary The effect of pentobarbital was studied in a mixed population of nerve and glial cells dissociated from brains of 7-day chick embryos and maintained in culture. Pentobarbital-Na was added in various concentrations ranging from 5×10^–5 M to 1×10^–3 M. The neuronal density was monitored by counting of neurons, neuronal identity was established by staining for Nissl Bodies and acetylcholinesterase. Over a culture period of 3 weeks, it was found that the barbiturate exerts a preferential dose-dependent cytotoxic effect on neurons.The expert technical assistance of Miss A. Wolf is appreciated. This work was supported by grant 6-74-27, INSERM (Physiologie et Pathologie du Développement Nerveux).     

Simplifications to substrate preparation for the cultivation of dissociated nerve cells

Résumé Nous avons simplifié la méthode de préparation du substrat «collagène» pour la culture de cellules nerveuses dissociées. On obtient une fixation et une différenciation rapide des cellules sur ce substrat. Les cultures conviennent pour des études morphologiques, biochimiques et électrophysiologiques.

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Chargée de Recherche au CNRS.

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Acknowledgments. The technical assistance of Mrs.Dorea van Weele andMrs. Marie-France Knoetgen is gratefully acknowledged.     

The ovalbumin gene region: common features in the organisation of three genes expressed in chicken oviduct under hormonal control.

Two large DNA fragments overlapping the chicken ovalbumin gene have been isolated by molecular cloning. Analysis of these fragments provided a map of a 46,000-base pair region of the chicken genome. This region contains the complete ovalbumin gene (including its mRNA leader-coding sequence) and at least two other genes of unknown function. All three genes are orientated in the same direction and their expression in chicken oviduct is under hormonal control. The three genes share some sequence homologies, suggesting that duplications have occurred in the ovalbumin gene region in the course of evolution.     

A 1.5 million-base pair inversion polymorphism in families with Williams-Beuren syndrome.

Williams-Beuren syndrome (WBS) is most often caused by hemizygous deletion of a 1.5-Mb interval encompassing at least 17 genes at 7q11.23 (refs. 1,2). As with many other haploinsufficiency diseases, the mechanism underlying the WBS deletion is thought to be unequal meiotic recombination, probably mediated by the highly homologous DNA that flanks the commonly deleted region. Here, we report the use of interphase fluorescence in situ hybridization (FISH) and pulsed-field gel electrophoresis (PFGE) to identify a genomic polymorphism in families with WBS, consisting of an inversion of the WBS region. We have observed that the inversion is hemizygous in 3 of 11 (27%) atypical affected individuals who show a subset of the WBS phenotypic spectrum but do not carry the typical WBS microdeletion. Two of these individuals also have a parent who carries the inversion. In addition, in 4 of 12 (33%) families with a proband carrying the WBS deletion, we observed the inversion exclusively in the parent transmitting the disease-related chromosome. These results suggest the presence of a newly identified genomic variant within the population that may be associated with the disease. It may result in predisposition to primarily WBS-causing microdeletions, but may also cause translocations and inversions.