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971.
Myelin-associated glycoprotein (MAG) is a quantitatively minor component in both peripheral and central myelin sheaths that is thought to have a role in cell-cell interactions within the nervous system. We show here that a mouse monoclonal antibody, HNK-1, which is directed against human natural killer cells also recognizes an antigenic determinant of human central and peripheral nervous system white matter by immunoperoxidase staining of tissue sections. Immunoblot analysis of myelin proteins and purified extracted MAG indicates that the antigen recognized is MAG. 相似文献
972.
973.
Loss of a Harvey ras allele in sporadic Wilms' tumour 总被引:5,自引:0,他引:5
A E Reeve P J Housiaux R J Gardner W E Chewings R M Grindley L J Millow 《Nature》1984,309(5964):174-176
Genomic changes within chromosome band 11p13 appear to have a role in the initiation of Wilms' tumour. The human Harvey ras oncogene, c-Ha-ras 1, has been located by Jhanwar et al. immediately adjacent to this region at band 11p14 .1, although several groups have assigned the gene more distally at band 11p15 . We have examined tumour DNA from two cases of sporadic Wilms' tumour, and report here that in both cases one of the two constitutional c-Ha-ras 1 alleles was absent. One tumour had a reciprocal translocation between the short arm of chromosome 11 (at band 11p13), and the long arm of chromosome 12, with no visible loss of chromosomal material. The loss of a c-Ha-ras 1 allele in association with this translocation indicates that a submicroscopic deletion had occurred. The resulting hemizygosity may have had a role in tumour initiation. Our results indicate that the c-Ha-ras 1 gene and the 'Wilms' tumour locus' may be in close proximity. It would, therefore, be premature to exclude the possibility that these two sites are functionally related. 相似文献
974.
975.
Charged groups play a critical role in the stability of the helix formed by the isolated C-peptide (residues 1-13 of ribonuclease A) in aqueous solution. One charged-group effect may arise from interactions between charged residues at either end of the helix and the helix dipole. We report here that studies of C-peptide analogues support the helix dipole model, and provide further evidence for the importance of electrostatic interactions not included in the Zimm-Bragg model for alpha-helix formation. 相似文献
976.
The paper studies some important issues concerning the classification of industrialregions at the county-level by using methods of correlation-principal component analysis and fuzzycluster technique.According to reality it also gives a case study in which the connty-level industrialregional classification is simulated. 相似文献
977.
Superattenuation in the tryptophan operon of Serratia marcescens 总被引:6,自引:0,他引:6
978.
979.
A transposon in Streptococcus faecalis with fertility properties 总被引:60,自引:0,他引:60
980.
Summary Desheathed rabbit vagus nerve has been found to form cyclic AMP when incubated with adenosine. This accumulation of cyclic AMP is inhibited by theophylline but not by antiadrenergic agents, anticholinergic agents or local anaesthetics. Depolarizing media are not able to promote cyclic AMP accumulation in this preparation.Acknowledgment. We gratefully acknowledge Mr.G. Jones for valuable discussion, MrsM. Moosmayer and Mr.S. Ferrara for expert technical assistance and Swiss National Science Foundation for grant support (Nr. 3.478.0.75). 相似文献