PubMed Health⌕ Search

Biomedical subjects

A Cahn

Publications and source records attributed to A Cahn.

8 recordsLinked to original sources

Homozygous deletions at 3p12 in breast and lung cancer.

We have constructed a physical map of the region homozygously deleted in the U2020 cell line at 3p12, including the location of putative CpG islands. Adjacent to one of these islands, we have identified and cloned a new gene (DUTT1) and used probes from this gene to detect two other homozygous deletions occurring in lung and breast carcinomas: the smallest deletion is within the gene itself and would result in a truncated protein. The DUTT1 gene is a member of the neural cell adhesion molecule family, although its widespread expression suggests it plays a less specialized role compared to other members of the family.

Breast Neoplasms↗

Characterization of SCML1, a new gene in Xp22, with homology to developmental polycomb genes.

Using exon trapping, we have identified a new human gene in Xp22 encoding a 3-kb mRNA. Expression of this RNA is detectable in a range of tissues but is most pronounced in skeletal muscle and heart. The gene, designated "sex comb on midleg-like-1" (SCML1), maps 14 kb centromeric of marker DXS418, between DXS418 and DXS7994, and is transcribed from telomere to centromere. SCML1 spans 18 kb of genomic DNA, consists of six exons, and has a 624-bp open reading frame. The predicted 27-kDa SCML1 protein contains two domains that each have a high homology to two Drosophila transcriptional repressors of the polycomb group (PcG) genes and their homologues in mouse and human. PcG genes are known to be involved in the regulation of homeotic genes, and the mammalian homologues of the PcG genes repress the expression of Hox genes. SCML1 appears to be a new human member of this gene group and may play an important role in the control of embryonal development.

Amino Acid Sequence↗

Thioredoxin, a mediator of growth inhibition, maps to 9q31.

The human thioredoxin gene has been provisionally mapped to 3p11-p12. Recently thioredoxin cDNA has been isolated in a procedure that detects transcripts coding for growth-suppressing proteins, and thus the chromosomal location of the gene is of particular interest. Chromosome 3 is believed to harbor several tumor suppressor genes important in the development of lung and other common epithelial tumors. To establish more firmly the chromosomal location of the human thioredoxin gene, a somatic hybrid panel was used; it identified chromosome 9 as the location of the transcribed thioredoxin gene. Fluorescence in situ hybridization of a YAC encoding the transcribed thioredoxin gene refined the localization to 9q31.

Animals↗

The classification of children's knowledge: development on the balance-scale and inclined-plane tasks.

R.S. Siegler (1981, Monographs of the Society for Research in Child Development, 46 C2, Serial No. 189) has shown that performance on several Piagetian tasks is governed by similar rule structures. The purpose of the first study was to extend his analysis to the inclined-plane task, replicate his original observations about development on the balance-scale task, and determine the consistency in children's rule usage across tasks. We found that Siegler's (1981) binary decision representations adequately characterized development on these tasks, and there was fair correspondence of rule classifications across tasks. An alternative classification procedure, used to diagnose the rules of children who failed our original classification criteria, showed that most of these children's performance patterns were very similar to Siegler's rule patterns. In the second experiment, we improved the diagnosticity of our rule-assessment protocol in light of F. Wilkening and N. H. Anderson's (1982, Psychological Bulletin, 92, 215-237) criticisms, and observed that many Rule III children's predictions were associated with those of integration rules on both tasks. Despite these methodological improvements, many children, especially 5- to 7-year-olds, evidenced use of centration and lexicographic strategies, suggesting that these classifications are not simply an artifact of problem sampling. Some of the problems associated with the classification of children's knowledge are discussed.

Child↗

Upright and inverted faces: the right hemisphere knows the difference.

The existence of a right hemisphere capacity, specific to upright faces was investigated. Upright and inverted faces, equally complex as patterns, were presented under lateralized tachistoscopic conditions to two groups of normal adult subjects. A significant orientation by visual field advantage was found. While there was a highly significant left visual field advantage for upright faces, the visual field difference for inverted faces failed to reach significane. This pattern of results supports the hypothesis that the right hemisphere is specialized for the perception of faces in particular, in addition to its specialization for the perception of visuospatial patterns in general.

Adult↗

Stroke of genius.

Explore the source record for details and available documents.

Hospital Units↗