Colon cancer presenting as Streptococcus gallolyticus infective endocarditis.

A 58-year-old Chinese man presented with a three-week history of fever. He had a background history of rheumatic heart disease, hypertension, and thalassaemia. He was found to have infective endocarditis of the aortic valve due to Streptococcus gallolyticus. During the hospital stay, he developed a few episodes of haematochaezia and was subsequently found to have colonic carcinomain- situ. He completed appropriate antibiotic treatment for his infective endocarditis and underwent a left hemicolectomy with primary anastomosis. The association between Streptococcus gallolyticus infective endocarditis and colonic neoplasm is well documented. This case report stresses the importance of performing routine colonoscopy to look for colonic neoplastic change in patients diagnosed to have Streptococcus gallolyticus infective endocarditis. The early diagnosis of the colonic neoplasm has enabled our patient to have a curative surgery without compromising his quality of life.

The impact of time-to-balloon on outcomes in patients undergoing modern primary angioplasty for acute myocardial infarction.

INTRODUCTION: The importance of time-to-primary percutaneous coronary intervention (PCI) in patients with acute myocardial infarction has been controversial. We examine the relationship between time-to-treatment and short- to medium-term clinical outcomes. METHODS: In a prospective observational study of data collected from our institution's angioplasty database between June 2001 and May 2003, 208 consecutive patients (mean age 56.0 [range, 28-90] years; 88.5 percent men; 23.6 percent with diabetes mellitus) with ST-segment elevation myocardial infarction (STEMI) and who underwent primary PCI without antecedent fibrinolytic therapy were analysed. With adjustments for appropriate covariates, logistic regressions were performed to assess the relationship between symptom-to-balloon time, door-to-balloon time and the studied outcomes, which were mortality and major adverse cardiac event (MACE) defined as death, myocardial infarction and repeat target vessel revascularisation. RESULTS: Prolonged symptom-to-balloon time (median time, 3 hours 55 minutes) significantly increased the MACE rate at one month (odds-ratio [OR], 1.45; 95 percent confidence interval [CI], 1.09-1.92; p-value is 0.011) and six months (OR, 1.19; 95 percent CI, 1.01-1.41; p-value is 0.046) but not mortality (at one month, p-value is 0.25; at six months, p-value is 0.87) after adjusting for relevant covariates. However, door-to-balloon time (median time, 110 minutes) did not significantly influence mortality (mortality at one month, p-value is 0.73; six months, p-value is 0.64) and MACE (MACE at one month, p-value is 0.71; six months, p-value is 0.08) at one and six months. CONCLUSION: Symptom-to-balloon time is an important predictor of MACE in the short- and medium-term in contrast to door-to-balloon time. Improving public awareness and accessibility of health services to patients with STEMI is essential in reducing poor outcomes.

Estradiol-17 beta dehydrogenase from chicken liver.

NADP+-linked estradiol-17 beta dehydrogenase has been purified 300- to 400-fold from cell-free extracts of chicken liver in a 20 to 30% yield by ammonium sulfate precipitation, ion exchange chromatography, and gel filtration. The enzyme is stable for at least 3 months when stored at -20 degrees C in buffer containing glycerol (50%, v/v). Two forms, with molecular weights of 43,000 and 97,000 are present; these show one major band (Rm = 0.27) and one minor band (Rm = 0.25) on polyacrylamide disc gel electrophoresis. (Rm is defined as the ratio of the distance migrated by the protein band to that of the tracking dye.) The species of lower molecular weight is the more active, with apparent Km values for estradiol-17 beta of 25 and 17.3 microM in the presence and absence, respectively, of bovine serum albumin in the assay medium. The apparent Km for NADP+ is 7.7 microM, and the optimum pH for dehydrogenation is 9.9. The lower molecular weight form has a lambda max at 280 nm, a shoulder at 290 nm, and an A 1% 1 cm of 12.1 at 280 nm. The fluorescence spectrum corresponds to that of a tryptophan-containing protein with lambda max at 288 nm. Isoelectric focusing in gel at pH 5 to 8 shows three major bands of pI 6.9, 6.8, and 6.0. Cross-linking with dimethyl suberimidate followed by electrophoresis reveals five bands. The enzyme is affected by thio reagents and possesses no associated estradiol-sensitive transhydrogenase activity.

Inactivation and modification of lactate oxidase with fluorodinitrobenzene.

1. Dinitrophenylation of 2 +/- 0.2mol of residues/mol of enzyme-bound FMN resulted in the complete inactivation of the flavoenzyme L-lactate oxidase. 2. Hydrolysates of the inactivated enzyme contained 1mol each of Nim-Dnp-histidine (abbreviation: Dnp-,2,4-dinitrophenyl-; Nim indicates that either of the N atoms in the imidazole ring is substituted) and epsilon-Dnp-lysine/mol of FMN. 3. Competitive inhibitors decreased the extent of inactivation to a 10% loss of activity, and dinitrophenylation was decreased from 2 to approx. 0.5mol/mol of FMN. Only Nim-Dnp-histidine was detected in the hydrolysates. 4. Although the dinitrophenylated enzyme did not possess enzyme activitiy, L-lactate reduced approx. 50% of the enzyme-bound flavin slowly (0.6min-1), and approx. 50% of the flavin in the modified enzyme-bound flavin slowly (0.6min-1), and approx. 50% of the flavin in the modified enzyme formed a complex with bisulphite. 6. The modified enzyme (2mol of Dnp/mol of FMN) was unable to bind substrate analogues and competitive inhibitors.

The structure of L-lactate oxidase from Mycobacterium smegmatis.

1. An improved purification was developed for L-lactate oxidase from Mycobacterium smegmatis. 2. The mol.wt. of the native enzyme by a sedimentation-equilibrium analysis was 345 000, and other ultracentrifuge methods gave values in the range 345 000-350 000. 3. An amino acid analysis, determinations of protein and flavin, a sedimentation-velocity analysis and an approach to equilibrium analysis gave values for the subunit mol.wt. in the range 43 500-47 000. 4. It was concluded that L-lactate oxidase contains eight subunits of mol.wt. 43 500. 5. Cross-linking of the subunits with dimethyl suberimidate and electron-microscopy studies were consistent with an octameric structure.

Modification of lactate oxidase with diethyl pyrocarbonate. Evidence for an active-site histidine residue.

1. Diethyl pyrocarbonate inactivated l-lactate oxidase from Mycobacterium smegmatis. 2. Two histidine residues underwent ethoxycarbonylation when the enzyme was treated with sufficient reagent to abolish more than 90% of the enzyme activity, but analyses of the inactivation showed that the modification of one histidine residue was sufficient to cause the loss of enzyme activity. The rates of enzyme inactivation and histidine modification were the same. 3. Substrate and competitive inhibitors decreased the maximum extent of inactivation to a 50% loss of enzyme activity and modification was decreased from 1.9 to 0.75-1.2 histidine residues modified/molecule of FMN. 4. Treatment of the enzyme with diethyl [(14)C]pyrocarbonate (labelled in the carbonyl groups) confirmed that only histidine residues were modified under the conditions used and that deacylation of the ethoxycarbonylhistidine residues by hydroxylamine was concomitant with the removal of the (14)C label and the re-activation of the enzyme. 5. No evidence was found for modification of tryptophan, tyrosine or cysteine residues, and no difference was detected between the conformation and subunit structure of the modified and native enzyme. 6. Modification of the enzyme with diethyl pyrocarbonate did not alter the following properties: the binding of competitive inhibitors, bisulphite and substrate or the chemical reduction of the flavin group to the semiquinone or fully reduced states. The normal reduction of the flavin by lactate was, however, abolished.