Size and stabilization of the dorsoulnar fragment in AO C3-type distal radius fractures.

INTRODUCTION: Volar locking plate (VLP) fixation has become the gold-standard treatment for distal radius fractures (DRFs). Especially, internal fixation of the volar lunate facet fragment is essential for the treatment of AO C3-type DRFs. On the other hand, the necessity of the fixation of the dorsal lunate facet fragment (dorsoulnar fragment) remains unclear. The purpose of the present study was to measure three-dimensionally the size of the dorsoulnar fragments in AO C3-type DRFs using computed tomography (CT) images in detail, and to reveal relationships of the size and stabilization of the dorsoulnar fragment with postoperative fracture displacement after VLP fixation. MATERIALS AND METHODS: We retrospectively reviewed the 101 consecutive Japanese patients who underwent surgical treatment for AO C3-type distal radius fractures. If patient had dorsoulnar fragment, the three-dimensional size of this fragment and the occupying ratio to the radiocarpal joint (RCJ) and the distal radioulnar joint (DRUJ) were anatomically evaluated using the preoperative CT images. In addition, we investigated the relationship of the size and stabilization of the dorsoulnar fragment with fracture displacement after VLP fixation. We statistically compared the size parameters and occupying ratio of the dorsoulnar fragment between the displaced group and the stable groups using a two-tailed t-test. We also statistically compared the numbers of screws inserted into the dorsoulnar fragments between the displaced and stable groups using a chi-square test. RESULTS: The mean dorsoulnar fragment size was 9.4 mm × 7.9 mm × 11.0 mm and the occupying ratio to the DRUJ and RCJ was 50% and 10%, respectively. The number of patients treated with volar locking plate fixation was 77, of which 12 patients had postoperative displacements. Although the size of the dorsoulnar fragment was not associated with postoperative displacement, stabilization following screw insertion into the dorsoulnar fragment was significantly associated with displacement. CONCLUSION: Stabilization of the dorsoulnar fragment with at least one screw of the volar locking plate was necessary to prevent postoperative fracture displacement regardless of dorsoulnar fragment size in AO C3-type distal radius fractures.

Purification, cDNA cloning and modification of a defensin from the coconut rhinoceros beetle, Oryctes rhinoceros.

A novel member of the insect defensins, a family of antibacterial peptides, was purified from larvae of the coconut rhinoceros beetle, Oryctes rhinoceros, immunized with Escherichia coli. A full-size cDNA was cloned by combining reverse-transcription PCR (RT-PCR), and 5'- and 3'-rapid amplification of cDNA ends (RACE). Analysis of the O. rhinoceros defensin gene expression showed it to be expressed in the fat body and hemocyte, midgut and Malpighian tubules. O. rhinoceros defensin showed strong antibacterial activity against Staphylococcus aureus. A 9-mer peptide amidated at its C-terminus, AHCLAICRK-NH2 (Ala22-Lys30-NH2), was synthesized based on the deduced amino-acid sequence, assumed to be an active site sequence by analogy with the sequence of a defensin isolated from larvae of the beetle Allomyrina dichotoma. This peptide showed antibacterial activity against S. aureus, methicillin-resistant S. aureus, E. coli and Pseudomonas aeruginosa. We further modified this oligopeptide and synthesized five 9-mer peptides, ALRLAIRKR-NH2, ALLLAIRKR-NH2, AWLLAIRKR-NH2, ALYLAIRKR-NH2 and ALWLAIRKR-NH2. These oligopeptides showed strong antibacterial activity against Gram-negative and Gram-positive bacteria. The antibacterial effect of Ala22-Lys30-NH2 analogues was due to its interaction with bacterial membranes, judging from the leakage of liposome-entrapped glucose. These Ala22-Lys30-NH2 analogues did not show haemolytic activity and did not inhibit the growth of murine fibroblast cells or macrophages, except for AWLLAIRKR-NH2.

Synthesis and characterization of bactericidal oligopeptides designed on the basis of an insect anti-bacterial peptide.

Defensin from a beetle, Allomyrina dichotoma, is known to have anti-bacterial activity against Gram-positive bacteria. This peptide, which comprises 43 amino acid residues, was effective against methicillin-resistant Staphylococcus aureus. We identified the active site of beetle defensin by measuring anti-bacterial activity against S. aureus of 64 overlapping 12-mer peptides with either a free carboxylate or a free amide group at their C-termini. An LCAAHCLAIGRR-NH2 (19L-30R-NH2) fragment showed the greatest activity of the synthetic oligopeptides. The 19L-30R-NH2 fragment was effective against both Gram-positive and Gram-negative bacteria. CD spectra showed that the 19L-30R-NH2 fragment formed an alpha-helical structure in the lipidic environment. The anti-bacterial effect of the 19L-30R-NH2 fragment was due to its interaction with bacterial membranes, judging from the leakage of liposome-entrapped glucose. Its anti-bacterial activity was increased when certain amino acid residues were replaced. Truncated peptides having had some amino acids removed from the N-terminus of the 19L-30R-NH2 fragment (8-10-mer peptides) still had strong anti-bacterial activity. Deleting some amino acids from the C-terminal region of the fragment dramatically reduced activity, indicating that the C-terminal region of the 19L-30R-NH2 fragment, i.e. RR-NH2, is important for exerting anti-bacterial activity. The AHCLAIGRR-NH2 (22A-30R-NH2) fragment and its analogues exhibited about 3-fold and 9-12-fold higher activity against S. aureus than did the 19L-30R-NH2 fragment, and these analogues were effective against methicillin-resistant S. aureus and Pseudomonas aeruginosa isolated from patients. These oligopeptides showed no haemolytic activity and did not inhibit the growth of murine fibroblast cells.

Lateral sacral artery supply to an intramedullary arteriovenous fistula at the conus medullaris.

In this 25-year-old woman, severe low back pain, flaccid paraparesis, sensory disturbance of both legs and sphincter dysfunction resulted from an intramedullary conal arteriovenous malformation fed by an anterior spinal artery arising from the left sixth intercostal artery and by the left lateral sacral artery, a branch of the left internal iliac artery.