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We have previously described linkageassociation between reelin gene polymorphisms and autistic disorder. APOE also participates in the Reelin signaling pathway, by competitively antagonizing Reelin binding to APOE receptor 2 and to very-low-density lipoprotein receptors. The APOE2 protein variant displays the lowest receptor binding affinity compared with APOE3 and APOE4. In this study, we assess linkageassociation between primary autism and APOE alleles in 223 complete trios, from 119 simplex Italian families and 44 simplex and 29 multiplex Caucasian-American families. Statistically significant disequilibrium favors the transmission of 2 alleles to autistic offspring, over 3 and 4 (allele-wise transmissiondisequilibrium test TDT, χ26.16, 2 degrees of freedom d.f., P<0.05; genotype-wise TDT, χ210.68, 3 d.f., P<0.05). A novel 3r allele was also discovered in an autistic child and his mother. Autistic patients do not differ significantly from unaffected siblings (allele-wise TDT comparing autistic patients versus unaffected sibs, χ21.83, 2 d.f., P<0.40, not significant). The major limitation of this study consists of our small sample size of trios including one unaffected sibling, currently not possessing the statistical power necessary to conclusively discriminate a specific association of 2 with autism, from a distorted segregation pattern characterized by enhanced 2 transmission rates both to affected and unaffected offspring. Our findings are thus compatible with either (a) pathogenetic contributions by 2 alleles to autism spectrum vulnerability, requiring additional environmental andor genetic factors to yield an autistic syndrome, andor (b) a protective effect of 2 alleles against the enhanced risk of miscarriage and infertility previously described among parents of autistic children.

TheDrosophilaeggshell consists of three major proteinaceous layers: the vitelline membrane, the inner chorionic layer, and the outer endochorion. During the latter stages of oogenesis, the proteins that comprise these layers are synthesized and secreted by epithelial follicle cells which surround the maturing oocyte. While there is considerable knowledge of the structural units which comprise the eggshell layers, there is little knowledge of how individual proteins function or interact with one another to form the structure. Immunoelectron microscopy was used to follow the distribution of four different eggshell proteins in the assembling and mature eggshell. sV23 and sV17, follicle cell proteins synthesized during the early stages of eggshell formation (stages 8–10), were distributed within the vitelline membrane layer at all stages. Despite marked temporal differences in their accumulation profiles, s36 and s18, putative chorion proteins, were similarly distributed throughout the floor, pillars, and roof of the endochorion. Although the vitelline membrane appears to be morphologically complete by stage 11, developmental Western blots and immunolocalization data indicate that molecular dynamism persists within the layer throughout the subsequent choriogenic stages. During early chorion formation the vitelline membrane appears to act as a reservoir for chorion proteins since s36 was found predominantly in the vitelline membrane layer of stage 12 egg chambers. During the late choriogenic stages (13–14), both sV17 and sV23 are processed to smaller derivatives. Interactions between the eggshell layers were suggested by ultrastructural analysis of a sV23 protein null mutant which showed that the structural integrity of the outer chorion is dependent upon the presence of a vitelline membrane component.

The saturation of self-organized second-harmonic generation in optical fibers, predicted by the directional photoionization model and the phenomenological cumulative local-response model, is confronted with data of some previous experiments. It was found that the experimentally determined value of (I_2ω/I²_ω)_sat ranges from 0.2 × 10-¹⁶ to 2 × 10^-16 m²/W, which is in reasonable agreement with the predictions of the directional photoionization model. The self-organized parametric down conversion is proposed for a very effective preparation of optical fibers. Copyright 1995, 1999 Academic Press