Characterization of the human factor VIII gene. 1984.
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Biomedical subjects
Publications and source records attributed to D H Eaton.
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In the specialized ribosome system, a distinct pool of mutated ribosomes is dedicated to the translation of one particular mRNA species. This was accomplished by altering the Shine-Dalgarno sequence on the mRNA and its complementary anti-Shine-Dalgarno sequence on the plasmid-borne 16S rRNA gene. Here, using the specialized ribosome system, we were able to introduce mutations in key regions of the 16S rRNA and could study their effect on translation in vivo. The C1400 region has been implicated to play a role in the actual mRNA decoding process. Several ribosomal mutations were introduced in this region. We showed that substitution of the evolutionary highly conserved C1400 residue by a G- or an A-residue inhibits ribosomal activity by 80% and 50% respectively, whereas, a C to a U change at this conserved position does not affect overall ribosomal activity. The adjacent stem structure (1410-1490) was also examined. Disruption of the stem by replacing either one of the arms of this stem, with a different sequence, inhibits ribosomal activity by approximately 80%. A small but significant restoration of translation could be achieved by recreating a complementary stem with a different sequence. We found that full reversion of activity could be obtained when such mutated ribosomes were made spectinomycin resistant by introducing a C to A substitution at position 1192 which is located far away in the secondary structure map of the 16S rRNA molecule. Based on these results we conclude that some, but not all, of the nucleotides in the conserved C1400 region play a key role in translation.(ABSTRACT TRUNCATED AT 250 WORDS)
In 261 infants with vomiting, 11 duodenal abnormalities were diagnosed with fluid-aided ultrasound (US). These abnormalities included duodenal obstruction, malrotation with and without associated volvulus, incomplete rotation, and duodenal stenosis. US was the initial modality used in the evaluation of vomiting in these neonates and young infants. The overall sensitivity and specificity of fluid-aided US evaluation of duodenal abnormalities were 100% and 99%, respectively. (Workup bias limits the reliability of these figures.) Fluid-aided US examination of the stomach and duodenum provided a dynamic view of duodenal rotation and anatomy, and at the very least provided a method of triaging those infants who may require surgery, upper gastrointestinal series, or follow-up US to make a definitive diagnosis.
Ultrasound has been used in the diagnosis of hypertrophic pyloric stenosis since the first reports of its use with contact B mode scanners. Real-time imaging has allowed measurements of pyloric diameter, length, and muscle wall thickness. Wall thickness measurements taken with the pylorus in longitudinal (elongated) view improve diagnostic accuracy. Fluid aided real-time examination of 10 cases showed the ultrasound equivalent of the "double track" sign. This finding is the result of pyloric fluid compressed into smaller tracks as it is impinged upon circumferentially by the thickened circular muscle. This sign, previously seen in barium studies, although nonspecific, may prove to be a sensitive diagnostic criterion.
Sonographic diagnosis of 3 cases of renal candidiasis led to early diagnosis and treatment. Echogenic densities within a dilated pyelocalyceal system appeared to be the classic finding for obstructing candidal bezoars or candidal pyonephrosis in the premature neonate. Sonography was useful in guiding diagnostic and therapeutic percutaneous nephrostomies of very premature (900 and 750 g) infants. The ultrasonic findings of moderate echogenicity within dilated collecting systems in premature infants suggest pyonephrosis. Candidiasis should be considered as a prime cause.
Two adolescents with psoas muscle abscesses secondary to Crohn's disease are presented. Musculoskeletal signs of hip flexion and scoliosis led to early clinical suspicion. Computed tomography and ultrasonography demonstrated the extent of involvement and allowed specific preoperative diagnosis.
The complete 186,000 base-pair (bp) human factor VIII gene has been isolated and consists of 26 exons ranging in size from 69 to 3,106 bp and introns as large as 32.4 kilobases (kb). Nine kb of mRNA and protein-coding DNA has been sequenced and the mRNA termini have been mapped. The relationship between internal duplications in factor VIII and evolution of the gene is discussed.
The partial amino-acid sequence of purified human transforming growth factor-beta (TGF-beta) was used to identify a series of cDNA clones encoding the protein. The cDNA sequence indicates that the 112-amino acid monomeric form of the natural TGF-beta homodimer is derived proteolytically from a much longer precursor polypeptide which may be secreted. TGF-beta messenger RNA is synthesized in various normal and transformed cells.