The effect of shoulder magnetic resonance imaging on clinical decision making.

One hundred cases were prospectively evaluated to determine the impact of magnetic resonance imaging on clinical decision making in an orthopaedic practice devoted to the treatment of disorders about the shoulder. Each was analyzed for changes in the clinical diagnosis or treatment. A change that either changed the primary diagnosis or type of treatment (operative versus nonoperative) was classified as category one. If additional clinically relevant findings were noted on the imaging studies without altering the primary diagnosis, or if the form of treatment was modified but not changed from operative or nonoperative, it was considered category two. Among the 100 imaging studies reviewed, category one and two changes were observed in 11 and 7 cases, respectively. Magnetic resonance imaging was particularly helpful in diagnosing ganglion cysts about the shoulder, a category one change in three out of three cases. For specific diagnoses a category one or two change was observed in 17% (10 of 59), 29% (4 of 14), 8% (1 of 13),and 100% (2 of 2) for rotator cuff disease, glenohumeral instability, adhesive capsulitis, and biceps disease, respectively. In 35 cases magnetic resonance imaging was considered to be unnecessary for the diagnosis or treatment of the patient. For the 65 patients who underwent magnetic resonance imaging, category one and two changes were noted in 10 and 5 patients, respectively. Statistical significance was demonstrated for category one changes in the entire group (100 cases) and the in subgroup recommended for magnetic resonance imaging (65 cases) (p < 0.05), indicating that the judicious use of magnetic resonance imaging can have a significant increase its impact on clinical decision making. Magnetic resonance imaging was found to be of limited diagnostic value in patients with an isolated primary clinical diagnosis of adhesive capsulitis, glenohumeral or acromioclavicular arthritis, brachial plexopathy, and cervical degenerative disk disease.

The influence of intramedullary fixation on figure-of-eight wiring for surgical neck fractures of the proximal humerus: a biomechanical comparison.

The resistance to torsional load was measured in a human cadaver model of a surgical neck fracture. Ten fresh-frozen human cadaver shoulders were thawed, dissected free of soft tissue attachments, and analyzed with dual energy x-ray absorptiometry to establish bone mineral density. Osteotomies were fixed with figure-of-eight wire alone and figure-of-eight wire supplemented with intramedullary Enders rods. Intramedullary Enders rods improved the mean maximum load by 1.5 times (p < 0.05). No statistically significant correlation was found between mean maximum load and bone mineral density.

Determination of common structural features in Escherichia coli promoters by computer analysis.

Escherichia coli promoters show a large degree of sequence variation. However, they are all recognized specifically by RNA polymerase as the sites for transcription initiation, suggesting that they share common basic structural features distinguishing them from the rest of the sequence. Our hypothesis is that the promoter is determined not only by the two consensus sequences at -10 and -35, but also by the surrounding nucleotides, and that it is not only the identity of the nucleotides that is important for promoter function but the presence of specific physical-chemical and structural characteristics that are sequence dependent. This approach is supported by accumulating evidence indicating the role that the DNA conformation may play in modulating protein-DNA interaction. In this study, four intrinsic sequence-dependent characteristics are examined in E. coli promoter regions: helix stability, helix flexibility, and two conformational parameters represented by the DNA tendencies for B-->Z and B-->A transition. The promoter is defined by the consensus sequences and their vicinity and the examined properties are compared between promoter and random sequences. It is demonstrated that both the consensus and flanking regions are less stable, more flexible and show a higher tendency for the B conformation in comparison to random sequences. Discriminant analysis is used to evaluate the relative contributions of the various characteristics.

Compilation of E. coli mRNA promoter sequences.

An updated compilation of 300 E. coli mRNA promoter sequences is presented. For each sequence the most recent relevant paper was checked, to verify the location of the transcriptional start position as identified experimentally. We comment on the reliability of the sequence databanks and analyze the conservation of known promoter features in the current compilation. This database is available by E-mail.

Hand infections.

The diagnosis and treatment of common hand infections are reviewed. A practical approach to the treatment of these conditions is detailed. This approach emphasizes the anatomic compartments of the hand, the microbiology of infecting organisms, and the patient conditions which modify treatment. Prompt and accurate diagnosis, treatment, and rehabilitation are key for optimal outcome.

Recovery of normal testicular ultrastructure and sperm motility after cessation of gossypol treatment in rats.

This study evaluates the reversibility of the effects of gossypol on testicular ultrastructure and the motility of epididymal spermatozoa. Adult male rats were treated 6 days weekly with the vehicle alone (Group A), or with 10 (Group B) or 20 (Group C) mg/kg of gossypol for 12 weeks, and then sacrificed six or 12 weeks after cessation of treatment. Although epididymal spermatozoa in Groups B and C were 100% immotile after gossypol treatment, little evidence of abnormality could be detected with the light microscope in the seminiferous tubules or interstitium. By contrast, at the ultrastructural level, there were demonstrable pathognomonic defects in the mitochondrial sheath and axonemes of step 18 and 19 spermatids which were identical to those reported earlier (Hoffer, 1983). In addition, an ultrastructural defect in the flagella of late testicular spermatozoa is described for the first time. This defect consists of an indentation, or constriction, of the mitochondrial sheath at outer dense fibers (ODFs) 1, 2, and 9, resulting in a separation of these 3 ODFs from the other fibers. This defect, though visible in an earlier ultrastructural study (Hoffer, 1983), was not described. In Group B rats allowed to recover from gossypol treatment, ultrastructural defects in step 18 and 19 spermatids could not be detected at six or at 12 weeks after cessation of treatment, and sperm motility also did not differ significantly from controls by the end of either recovery period. In Group C rats, sperm motility returned to the normal range within six weeks after treatment ended, but a few morphological defects in the midpiece and axoneme of late spermatids could still be detected with the electron microscope.(ABSTRACT TRUNCATED AT 250 WORDS)