Enzyme replacement in Tay-Sachs disease.

Enzyme replacement therapy was attempted with two Tay-Sachs-diseased individuals--a 14-month-old child and a 7-week-old infant. Treatment consisted of repeated weekly intrathecal injections of pure hexosaminidase A. Injection of this enzyme resulted in almost complete disappearance of GM2 from the serum, but did not bring about dissolution of the GM2 membranous cytoplasmic bodies in the brain, as detected by electronmicroscopy. Both patients tolerated the treatment without apparent clinical complications, but no clear-cut improvement was noted as a result of prolonged injections of hexosaminidase A. Since this treatment was initiated in both an advanced stage and a very early stage of the disease, we conclude that enzyme replacement treatment by this route is not beneficial for patients with Tay-Sachs disease.

A survey of amniocentesis in 925 patients at high risk of fetal genetic disorder.

Over a nine-year period, 925 pregnancies at an Israeli medical centre were selected for investigation by amniocentesis for genetic reasons. In only 30 pregnancies did failure of laboratory methods or difficulty with amniocentesis lead to a lack of results with which to assess the normality of the fetus. The information obtained by examination of the amniotic fluid in the other 895 pregnancies is presented and discussed.

Affiliation before and after child delivery as a function of repression-sensitization.

A group of 177 women were asked, before and after child delivery, to state their preference for being alone or with other women. They were also asked to rank their level of anxiety. After delivery they filled out the Repression-Sensitization Scale of Byrne, Barry & Nelson (1963). Results show sensitizers to be more anxious than repressors before but not after delivery. Before delivery repressors preferred to be alone, while sensitizers wanted to stay with others. After delivery both groups show a significant preference for being with others. There is no significant correlation between anxiety and affiliation.

Genetic and environmental correlations between brain weight and maze learning in inbred strains of mice and their F1 hybrids.

The relationships among body weight, cerebellum weight, cerebrum weight, maze-learning ability in a double T-maze, and discrimination learning in a Y-maze were studied in six inbred strains of mice and some of their F1 hybrids. The subjects were 131 male albino mice from 14 genotypic groups: five inbred groups and nine groups of crossbred offspring. Intra- and intergroup correlations were computed between all possible pairs of the anatomical and behavioral traits. A significant difference between the intragroup and intergroup correlations for any pair of variables was taken to indicate the presence of a genetic correlation between the two variables. On this basis, positive genetic correlations were indicated between T-maze learning ability and Y-maze learning ability, between body weight and T-maze learning ability, and possibility between body weight and both cerebellum and cerebrum weight and between cerebrum weight and T-maze learning ability. Negative genetic correlations were indicated between cerebellum weight and running time in both mazes and between total number of successes in the Y-maze and Y-maze running time.