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L M Bird

Publications and source records attributed to L M Bird.

21 records · Page 2Linked to original sources

Two craniosynostotic syndrome loci, Crouzon and Jackson-Weiss, map to chromosome 10q23-q26.

Crouzon syndrome (MIM 123500) is a common autosomal dominant form of craniosynostosis with shallow orbits, ocular proptosis, and maxillary hypoplasia. Jackson-Weiss syndrome (MIM 123150) is another autosomal dominant craniosynostosis with highly variable phenotypic expression. Unlike Crouzon syndrome, Jackson-Weiss syndrome is associated with foot anomalies. We performed two point linkage and haplotype analyses using 13 dinucleotide repeat markers on chromosome 10, spanning a genetic distance of 108 cM. The Crouzon syndrome locus (CFD1) maps to the region of chromosome 10q2, with the tightest linkage to locus D10S205 (Z = 3.09, theta = 0.00). the Jackson-Weiss syndrome locus in the large Amish pedigree in which the condition was originally described was also linked to the chromosome 10q23-q26 region between loci D10S190 and D10S186. The D10S209 locus was most strongly linked (Z = 11.29, theta = 0.00).

Abnormalities, Multiple↗

The effects of aminophylline and nifedipine on contractility of isolated pregnant human myometrium.

To characterize the effects of aminophylline and nifedipine on pregnant human myometrium, in vitro contractility studies were performed on myometrial strips obtained at cesarean section. The strips were stimulated with oxytocin (800 mU/L) to simulate labor and then were exposed to increasing concentrations of aminophylline (40, 100, and 400 mumol/L) or nifedipine (5, 10, and 20 micrograms/L). Both drugs produced a dose-related decrease in contraction strength, as measured by the time-integrated force of contraction. Aminophylline lengthened the period of contraction in a manner that was not dose dependent. Low-dose nifedipine (5 micrograms/L) increased the period of contraction, but higher doses had no effect on frequency. Both drugs produced a net reduction in the effectiveness of labor, as measured by the average force (time-integrated force divided by period). These results indicate that both aminophylline and nifedipine may be clinically useful tocolytic agents.

Aminophylline↗

Genetic mapping of X-linked loci involved in skewing of X chromosome inactivation in the human.

We have analyzed X-chromosome inactivation patterns in lymphocytes of 264 females from 38 families not known to have any genetic disease. Quantitative measures of X-inactivation showed strong sister-sister correlation in the degree of departure from equal numbers of cells having each X chromosome active, suggesting heritability of this phenotype. Strong sister-sister correlation was also observed for the fraction of cells having the same parent's X chromosome active, consistent with the possibility that this trait might be controlled by a cis-acting, X-linked gene. We used a sib-pair approach to determine whether X-inactivation phenotype was linked to loci in any region of the X chromosome. Both quantitative and discrete measures of X-inactivation phenotype showed evidence of linkage to markers in the region of the X inactivation center (XIC). The quantitative measure of X-inactivation phenotype used in our study also showed linkage to loci at Xq25-q26. This study provides the first evidence for X-linked inheritance of X chromosome inactivation phenotype derived from linkage analysis in phenotypically normal human families.

Base Sequence↗