Evaluation of the 4-hour RapID NF Plus method for identification of 345 gram-negative nonfermentative rods.

The ability of the RapID NF Plus system (Innovative Diagnostic Systems, Inc., Atlanta, Ga.) to identify 345 nonfermentative gram-negative rods was evaluated. Kits were inoculated with no. 1 McFarland suspensions, and reactions were interpreted after a 4-h incubation at 35 degrees C. Overall, the method correctly identified 311 strains (90.1%) without additional tests and 21 strains (6.1%) with additional tests, and 13 strains (3.8%) were misidentified. Five of 13 misidentified strains were Alcaligenes faecalis-Alcaligenes odorans misidentified as Alcaligenes xylosoxidans; however, all strains were xylose negative but nitrate positive and could have been A. faecalis group I-Alcaligenes piechaudii. The system does not differentiate between Pseudomonas fluorescens and Pseudomonas putida, and all Acinetobacter species are identified as Acetinobacter calcoaceticus. Additionally, no subspecies differentiation is made between A. xylosoxidans subsp. xylosoxidans and A. xylosoxidans subsp. denitrificans. All strains of the former Flavobacterium group IIb are identified as Flavobacterium indologenes-Flavobacterium gleum, and no species identification of the genus Methylobacterium is attempted. The system is easy to set up and interpret and provides an accurate commercial nonautomated method for same-day identification of gram-negative nonfermenters.     

Accuracy and reproducibility of the 4-hour ATB 32A method for anaerobe identification.

The ATB 32A system (API System SA, La Balme les Grottes, Montalieu-Vercieu, France) was evaluated for use in the identification of 214 anaerobes. Organisms included 73 isolates of the Bacteroides fragilis group, 24 Bacteroides spp., 10 fusobacteria, 43 clostridia, 28 cocci, and 36 gram-positive, nonsporeforming rods. With the concomitant use of Gram stain, pigmentation, catalase testing, and aerobic growth, the ATB 32A system correctly identified 97% of the B. fragilis group isolates, 88% of Bacteroides spp., 50% of fusobacteria, 74% of clostridia, 100% of cocci, and 86% of the gram-positive, nonsporeforming rods. Overall, 188 strains (88%) were correctly identified, with 18 (8%) requiring extra tests, other than the four mentioned above, for correct identification. Eight strains were misidentified, including one Bacteroides sp., three fusobacteria, one Clostridium sp., and three gram-positive, nonsporeforming rods. Reproducibility was very good, with 12 of 14 strains (86%) tested in triplicate yielding identical correct results on each of three occasions and 2 strains (14%) yielding identical correct results on two occasions. There was a low-probability identification (including the correct species) on the third testing. The ATB 32A system represents a worthwhile advance in systems used for the identification of clinically significant anaerobic bacteria.     

COMMON FEMORAL ARTERY FENESTRATION IN THE TREATMENT OF THORACIC AORTIC DISSECTION

SUMMARY Although dissection of the thoracic aorta is a common aortic emergency, little has been written about fenestration procedures to revascularise femoral arteries that have been occluded by dissecting aneurysms arising from as high as the thoracic aorta.     

Postoperative cardiac surgical care: an alternative approach

Combined appropriate anaesthetic and surgical techniques have allowed increasing numbers of patients to be successfully managed in a general surgical recovery ward after cardiac surgery rather than in an intensive care unit. From 1983 to 1989, 933 of 1542 patients undergoing open heart surgery were transferred to the general surgical recovery ward in the immediate postoperative period. Of these, 718 (77%) had undergone coronary artery bypass grafts, sometimes combined with other procedures and 168 (18%) had had cardiac valve replacements with or without other procedures. The remaining 47 (5%) had had miscellaneous cardiac operations. Significant cardiac complications occurred in 29 (3%) patients. The 24 hour chest radiograph was reported as abnormal (mainly atelectasis and effusion) in 63% of patients. Most resolved spontaneously or with physiotherapy. Twenty nine (3%) patients were re-explored to achieve haemostasis. There were no deaths in the general surgical recovery ward. Thirty seven (4%) patients had to be transferred to the intensive care unit for various reasons. The remaining 896 patients were transferred to the general ward after one night (871 patients) or two nights (25 patients) in the general surgical recovery ward. The average duration of stay in hospital for these patients was 9·3 days. Because of the overall success of such management and the low rate of complications over 80% of patients are now managed in the general surgical recovery ward after open heart surgery. The resulting savings in capital expenditure of equipment, medical, nursing, and technical personnel are substantial, and there are major implications for the planning of new cardiothoracic units.     

Patterns of 8-hydroxydeoxyguanosine formation in DNA and indications of oxidative stress in rat and human pleural mesothelial cells after exposure to crocidolite asbestos

Oxidative damage is a proposed mechanism of asbestos-induced carcinogenesis, but the detection of oxidative DNA lesions in target cells of asbestos-induced mesothelioma has not been examined. In studies here, DNA was isolated from both rat pleural mesothelial (RPM) cells and a human mesothelial cell line (MET5A) after exposure in vitro to crocidolite asbestos at various concentrations. DNA was then examined for formation of 8-hydroxydeoxyguanosine (8-OHdG) at 24, 48 and 72 h using HPLC with electrochemical detection. In addition, steady- state mRNA levels of manganese-containing superoxide dismutase (MnSOD) were assessed as an indication of oxidative stress. Whereas RPM cells showed dose-dependent and significant increases in 8-OHdG formation in response to crocidolite asbestos or iron-chelated crocidolite fibers (but not after exposure to glass beads), MET5A cells showed decreases in 8-OHdG. Both cell types exhibited elevations in message levels of MnSOD. In comparison with human MET5A cells, RPM cells exhibited increased cytotoxicity and apoptosis in response to asbestos, as documented by cell viability assays and flow cytometry analysis using propidium iodide. Results in RPM cells indicate that asbestos causes oxidative damage that may result in potentially mutagenic lesions in DNA and/or apoptosis, despite compensatory increases in expression of an antioxidant enzyme.