Lupus interstitial cystitis. Apropos of a case]

The poor results obtained with the use of prosthesis in infrapopliteal arterial bypass grafting for critical limb ischaemia led to the introduction of several types of adjuvant arteriovenous fistula to improve the patency and limb salvage rates in patients who have no suitable autologous vein. The main aim of adjunctive arteriovenous fistula in infrageniculate prosthetic bypass is to accelerate the blood flow velocity through the prosthetic graft above the thrombotic threshold level. Since they are subject of great debate among vascular surgeons, the Authors have briefly reviewed the haemodynamic aspects and results reported with the use of such procedures.     

Crystal structure of CcdB, a topoisomerase poison from E. coli

The crystal structure of CcdB, a protein that poisons Escherichia coli gyrase, was determined in three crystal forms. The protein consists of a five-stranded antiparallel beta-pleated sheet followed by a C-terminal alpha-helix. In one of the loops of the sheet, a second small three-stranded antiparallel beta-sheet is inserted that sticks out of the molecule as a wing. This wing contains the LysC proteolytic cleavage site that is protected by CcdA and, therefore, forms a likely CcdA recognition site. A dimer is formed by sheet extension and by extensive hydrophobic contacts involving three of the five methionine residues and the C terminus of the alpha-helix. The surface of the dimer on the side of the alpha-helix is overall negatively charged, while the opposite side as well as the wing sheet is dominated by positive charges. We propose that the CcdB dimer binds into the central hole of the 59 kDa N-terminal fragment of GyrA, after disruption of the head dimer interface of GyrA.     

Primary psoas abscess. A review of 16 cases

OBJECTIVE: Most psoas abscesses are secondary. The objective of this study was to report on the clinical features, diagnosis and treatment of primary psoas abscess. METHODS: We retrospectively studied 16 cases seen over a ten-year period (1987-1997) and compared our findings to published data. RESULTS: There were 14 men and two women, with a mean age of 6 years (range, 17-57 years). The right side was affected in nine cases, the left side in six, and both sides in one. Fever, pain and psoas spasm were the presenting symptoms. Laboratory tests for inflammation were positive; four patients had a high neutrophil count. Ultrasonography demonstrated a fluid collection in the psoas in 13 patients. A computed tomography scan was done in 14 patients and showed either a fluid collection (n = 11) or a presuppurative abscess (n = 3). Magnetic resonance imaging was not used. The organism was recovered in nine patients and was a Staphylococcus aureus in seven, an Escherichia coli in one and a Pseudomonas aeruginosa in one. The Brucella agglutination test was strongly positive in two patients. Findings were negative from investigations done to look for a cause (discitis, urinary tract infection, Crohn's disease, ulcerative colitis, malignancy or infection in the vicinity of the psoas muscle). All patients received antimicrobial therapy. Drainage was percutaneous in six patients and surgical in ten. The outcome was favorable in every case.     

Hemispheric asymmetry in the visual contribution to postural control in healthy adults

This study was carried out in order to test the hypothesis of a right hemisphere dominance in the visual control of body balance. Eight healthy adults were subjected to a self-regulated lateral balance task, performed while sitting on a rocking platform. Four visual conditions were tested: open eyes with normal vision, closed eyes in the dark, left visual field-right hemisphere and right visual field-left hemisphere. Head and support displacements in the roll plane were recorded by means of an optoelectronic system. Two main results emerged from this study: (1) head stabilization in space was much more efficient in the left visual field-right hemisphere condition than in the three other visual conditions, and (2) although vision played an important role in the body stability whatever the anatomical level, there was no right hemisphere dominance at the pelvic level. A clear right hemisphere dominance was thus demonstrated as regards the visual contribution to head stabilization in space.     

Bacterial death by DNA gyrase poisoning

DNA gyrase is an essential topoisomerase that is found in all bacteria and is the target of potent antibiotics, such as the quinolones. By creating DNA lesions and inducing the bacterial SOS response, these drugs are not only highly cytotoxic but also mutagenic. Discovery and analysis of natural molecules with anti-gyrase activities, such as the CcdB or microcin B17 proteins, hold promise for understanding further topoisomerase reactions and for the design of new antibiotics.