[Management of remaining coronary artery dissection after the replacement of the ascending aorta in acute type A aortic dissection].

The authors report a case study of a 54-year-old male admitted to our hospital with severe chest pain and ST depression in II, III and aVf lead on the electrocardiogram. The chest X-ray showed an enlarged superior mediastinum. An enhanced computed tomography (CT) was performed and confirmed the diagnosis of acute type A aortic dissection. The patient underwent emergency surgical repair with the replacement of the ascending aorta. The patient recovered without complication until the fifteenth postoperative day, when another severe chest pain appeared. Emergency coronary angiography revealed a remaining dissection in both the left anterior descending artery (LAD) and the left circumflex artery (LCx). Implantation of Elite stents to the LAD and the LCx was performed. The patient recovered uneventfully after this operation. Remaining coronary artery dissection after the replacement of the ascending aorta is very rare. In this case coronary intervention with Elite stents was effective.

Acid-base chemistry of the reaction of aromatic L-amino acid decarboxylase and dopa analyzed by transient and steady-state kinetics: preferential binding of the substrate with its amino group unprotonated.

Transient and steady-state kinetic analysis of the reaction of aromatic L-amino acid decarboxylase (AADC), a pyridoxal 5'-phosphate- (PLP-) dependent enzyme, with its substrate dopa was carried out at various pH. The association of AADC and dopa to form the Michaelis complex and the subsequent transaldimination reaction to form the dopa-PLP Schiff base (external aldimine) were followed with a stopped-flow spectrophotometer. Combined with the steady-state k(cat) value, we could present a minimum mechanism for the reaction of AADC and dopa. In the mechanism, the association of the aldimine-protonated form of the enzyme (EH(+)) and the alpha-amino-group-unprotonated form of the substrate (S) is the main route leading to the Michaelis complex. In addition, the association of EH(+) and the alpha-amino-group-protonated form of the substrate (SH(+)) to form a Michaelis complex EH(+).SH(+) was also found as a minor route. The pK(a) of the alpha-amino group of dopa was expected to be decreased in the Michaelis complex, promoting the conversion of EH(+).SH(+) to EH(+).S, the species that directly undergoes transaldimination to form the external aldimine complex. The association of EH(+) and S had been identified as a minor route for the reaction of aspartate and aspartate aminotransferase (AspAT), which has an unusually low pK(a) value of the aldimine and can use the aldimine-unprotonated form (E) of the enzyme for adsorbing the prevalent species SH(+) [Hayashi and Kagamiyama (1997) Biochemistry 36, 13558-13569]. The present study implies that, in most PLP enzymes that have a high pK(a) value of the aldimine like AADC, S preferentially binds to the enzyme (EH(+)). The minor route of EH(+) + SH(+) in AADC may be related to the flexibility of the protein in the Michaelis complex, and a simulation analysis showed that the presence of this route decreases the k(cat) value while increasing the k(cat)/K(m) value. It also suggested that AADC has evolved to suppress the minor route to the extent necessary to obtain the maximal k(cat) value at neutral pH.

[A case of solitary splenic abscess caused by Salmonella enteritidis and cured completely by antibiotic therapy alone].

Solitary splenic abscess is a rare disease and usually treated with splenectomy. A 78-year-old female with diabetes mellitus and liver cirrhosis was admitted to our hospital in a state of fever and left hypochondralgia. The abdominal ultrasonogram and CT scan showed the splenomegaly and one abnormal mass in the spleen. Drainage under sonographic guidance was attempted to the splenic mass but only a little amount of aspiration fluid was obtained, from which Salmonella Enteritidis was detected. No other abscess in the other organs was detected, resulting in the diagnosis as solitary splenic abscess caused by S. Enteritidis. Antibiotic therapy was carried out and the abscess disappeared judging from the ultrasonogram, CT scan, and laboratory data. The present case suggests that the fully application of ultrasonogram, CT scan, and drainage for the diagnosis leads to the healing of solitary splenic abscess without operation. This is the first case of S. Enteritidis infection in the spleen reported in Japan.