Sigmoid colon obstruction due to blunt abdominal trauma: a case report.

Post-traumatic colonic stenosis (obstruction) is rare. We experienced a case of sigmoid obstruction due to blunt abdominal trauma. A 75-year-old man was hit on the lower abdomen 3 days before admission and gradually developed abdominal pain and distension. Laboratory data showed severe inflammation and a barium enema disclosed obstruction of the sigmoid colon. Conservative treatment was carefully carried out, because there was no sign of peritoneal irritation and there were passages of normal stool and flatus. The sigmoid obstruction gradually improved and the stenosis was almost undetectable on a barium enema on the 51st hospital day. An abdominal contusion is the most likely causal factor in this case. Compression of the sigmoid colon between the abdominal wall and the promontory of the pelvis is the most possible explanation.&#60;/P&#62;</p

Structural basis for the substrate recognition of aminoglycoside 7′′-phosphotransferase-Ia from Streptomyces hygroscopicus

Hygromycin B (HygB) is one of the aminoglycoside antibiotics, and it is widely used as a reagent in molecular-biology experiments. Two kinases are known to inactivate HygB through phosphorylation: aminoglycoside 7′′-phosphotransferase-Ia [APH(7′′)-Ia] from Streptomyces hygroscopicus and aminoglycoside 4-phosphotransferase-Ia [APH(4)-Ia] from Escherichia coli. They phosphorylate the hydroxyl groups at positions 7′′ and 4 of the HygB molecule, respectively. Previously, the crystal structure of APH(4)-Ia was reported as a ternary complex with HygB and 5′-adenylyl-β,γ-imidodiphosphate (AMP-PNP). To investigate the differences in the substrate-recognition mechanism between APH(7′′)-Ia and APH(4)-Ia, the crystal structure of APH(7′′)-Ia complexed with HygB is reported. The overall structure of APH(7′′)-Ia is similar to those of other aminoglycoside phosphotransferases, including APH(4)-Ia, and consists of an N-terminal lobe (N-lobe) and a C-terminal lobe (C-lobe). The latter also comprises a core and a helical domain. Accordingly, the APH(7′′)-Ia and APH(4)-Ia structures fit globally when the structures are superposed at three catalytically important conserved residues, His, Asp and Asn, in the Brenner motif, which is conserved in aminoglycoside phosphotransferases as well as in eukaryotic protein kinases. On the other hand, the phosphorylated hydroxyl groups of HygB in both structures come close to the Asp residue, and the HygB molecules in each structure lie in opposite directions. These molecules were held by the helical domain in the C-lobe, which exhibited structural differences between the two kinases. Furthermore, based on the crystal structures of APH(7′′)-Ia and APH(4)-Ia, some mutated residues in their thermostable mutants reported previously were located at the same positions in the two enzymes