Radiologic abnormalities of the sternum in Turner's syndrome.

Various skeletal abnormalities, including chest deformity, have been reported with Turner's syndrome. We report radiologic findings of the sternum on lateral chest roentgenograms in 15 children and adolescents with Turner's syndrome, whose ages ranged between 2 weeks and 20 years. Eight had associated congenital heart disease (CHD). Twelve patients (80 percent) had various sternal abnormalities; 5 had short sternum, 3 had premature fusion of the manubrio-sternal junction, and 4 had premature fusion of the mesosternum. Five had decreased ratio of sternal body to manubrium. Three patients had two ossification centers of the manubrium. Four patients had bowing of the mesosternum; three of these had mild pectus excavatum also. In this series, children with and without CHD had similar sternal abnormalities. Although not pathognomonic, sternal abnormalities on a lateral chest roentgenogram are common skeletal abnormalities associated with Turner's syndrome and are independent of associated CHD. In our series of 15 patients, 10 had monosomy (45,X) on blood karyotype; 7 of them had associated CHD. This is the first systematic analysis of radiologic abnormalities of the sternum in Turner's syndrome and includes findings not previously reported.

Isolation, molecular characterization and expression of the ushB gene of Salmonella typhimurium which encodes a membrane-bound UDP-sugar hydrolase.

The UDP-sugar hydrolase of Salmonella typhimurium has previously been reported to be located in both the inner and the outer membrane. We have cloned the gene, designated ushB, encoding this enzyme and determined its nucleotide sequence. No significant sequence homology with the periplasmic UDP-sugar hydrolase of Escherichia coli was found at either the DNA or protein level. However, a sequence is detectable, in the E. coli genome, which weakly hybridizes with a specific ushB probe. Polypeptide analysis has allowed the identification of the Salmonella hydrolase which has an Mr of 28,349 as compared to an Mr of 60,767 for the E. coli hydrolase. Most of the protein (approximately 90%) is located in the inner membrane. Two independent membrane fractionation procedures indicate that the remainder may be associated with the outer membrane. The deduced primary structure indicates the presence of an N-terminal signal peptide, although certain features of the region surrounding the putative processing site indicate that processing may be inefficient, or may not occur. Experiments with several inhibitors of signal peptidase function fail to demonstrate the appearance of a precursor form.