Characterization of glutathione amide reductase from Chromatium gracile. Identification of a novel thiol peroxidase (Prx/Grx) fueled by glutathione amide redox cycling

Among the Chromatiaceae, the glutathione derivative gamma-l-glutamyl-l-cysteinylglycine amide, or glutathione amide, was reported to be present in facultative aerobic as well as in strictly anaerobic species. The gene (garB) encoding the central enzyme in glutathione amide cycling, glutathione amide reductase (GAR), has been isolated from Chromatium gracile, and its genomic organization has been examined. The garB gene is immediately preceded by an open reading frame encoding a novel 27.5-kDa chimeric enzyme composed of one N-terminal peroxiredoxin-like domain followed by a glutaredoxin-like C terminus. The 27.5-kDa enzyme was established in vitro to be a glutathione amide-dependent peroxidase, being the first example of a prokaryotic low molecular mass thiol-dependent peroxidase. Amino acid sequence alignment of GAR with the functionally homologous glutathione and trypanothione reductases emphasizes the conservation of the catalytically important redox-active disulfide and of regions involved in binding the FAD prosthetic group and the substrates glutathione amide disulfide and NADH. By establishing Michaelis constants of 97 and 13.2 microm for glutathione amide disulfide and NADH, respectively (in contrast to K(m) values of 6.9 mm for glutathione disulfide and 1.98 mm for NADPH), the exclusive substrate specificities of GAR have been documented. Specificity for the amidated disulfide cofactor partly can be explained by the substitution of Arg-37, shown by x-ray crystallographic data of the human glutathione reductase to hydrogen-bond one of the glutathione glycyl carboxylates, by the negatively charged Glu-21. On the other hand, the preference for the unusual electron donor, to some extent, has to rely on the substitution of the basic residues Arg-218, His-219, and Arg-224, which have been shown to interact in the human enzyme with the NADPH 2'-phosphate group, by Leu-197, Glu-198, and Phe-203. We suggest GAR to be the newest member of the class I flavoprotein disulfide reductase family of oxidoreductases.

Transluminal coronary balloon angioplasty: a useful therapeutic modality in octogenarian patients with severe angina

In this study, the immediate and short-term outcome of 9 consecutive patients aged 80 years or older undergoing percutaneous transluminal coronary angioplasty (PTCA) are reported. Of these 9 patients, 8, despite optimal medical therapy, had unstable Class IV anginal symptoms and 6 had multivessel coronary artery disease. Primary success at PTCA (successful dilation of all attempted lesions without any complications) was achieved in 8 of the 9 (89%) patients. The one patient with unsuccessful PTCA had subsequent successful elective coronary bypass graft surgery. The 8 patients with primary success at PTCA have been followed up for a mean of 27 +/- 15 (range: 6 to 45) months. During follow-up, no patient died, required a further revascularization procedure or had a myocardial infarction. Indeed, 7 of these 8 patients have, following PTCA, remained entirely asymptomatic with no decrease in their activity level. Angina has recurred in 1 patient but it is mild and does not restrict his activities. Based on our encouraging experience we suggest that PTCA should be considered favourably in the treatment of selected octogenarian patients with severe angina poorly controlled by medical therapy.

Outcome following coronary balloon angioplasty in young adults aged 35 years or less

The natural history of symptomatic young patients with coronary artery disease is often far from benign. Follow-up studies of young patients who have undergone coronary bypass graft surgery show frequent recurrence of symptoms and need for reoperation. Prompted by these considerations, we reviewed the records of 23 consecutive patients aged less than or equal to 35 years with symptomatic coronary artery disease, who underwent coronary balloon angioplasty at our center between August, 1984 and November, 1989. Mean patient age was 32 (3) (mean [SD]) years. Acute myocardial infarction was the first symptom of coronary artery disease in 7 (30%) of the 23 patients. At the time of angioplasty, 17 (74%) patients, had functional Class 3 or 4 anginal symptoms. Eight (35%) had multivessel coronary artery disease (stenoses greater than or equal to 70% in two or more major coronary arteries). Overall, a total of 36 critical coronary lesions were identified in 32 vessels of the 23 patients (mean of 1.6 lesions and 1.4 diseased vessels per patient). At angioplasty, dilatation of 31 lesions in 27 vessels was attempted. Multilesion angioplasty was attempted in 7 (30%) patients. Successful dilatation was achieved in 29 of the 31 (94%) lesions, and 25 of the 27 (93%) vessels. Primary clinical success (successful dilatation of all attempted lesions without any complications) was achieved in 21 of 23 (91%) patients. Three of the 21 patients with successful initial angioplasty had repeat angioplasty for restenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

First report of chronic meningitis caused by Trichosporon beigelii

Trichosporon beigelii (Trichosporon cutaneum) was identified as the causative agent of chronic meningitis in a 15-year-old boy with acute lymphocytic leukaemia. After a neutropenic episode following cytostatic treatment and itraconazole therapy as prophylaxis, cerebrospinal fluid (CSF) samples yielded growth of Trichosporon beigelii. Treatment with amphotericin B, flucytosine and high doses of fluconazole was followed by clinical improvement, although CSF pleocytosis remained. The cross-reactivity between Cryptococcus neoformans and Trichosporon beigelii in a cryptococcal antigen latex test was used as a means of diagnosis in CSF and serum samples.