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L M Lewis

Publications and source records attributed to L M Lewis.

57 records · Page 4Linked to original sources
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Can urinary nitrite results be used to guide antimicrobial choice for urinary tract infection?

Enterococcus is unable to reduce nitrates and is also considered clinically resistant to trimethoprim/sulfamethoxazole (TMP/SMX), the drug of choice for uncomplicated urinary tract infection (UTI). The purpose of this study was to determine whether urinalysis nitrite results can be used to guide antimicrobial therapy when treating UTI in the emergency department (ED). A retrospective chart review examined 159 university hospital ED outpatients who had signs or symptoms of UTI and had a urinalysis with positive culture. Patients were categorized into two groups based on nitrite results. The proportion of isolates sensitive to TMP/SMX in each group was compared by using a two-sample z-test. Eighty-six urinalyses were nitrite positive: 67 (78%) contained TMP/SMX-sensitive isolates. Seventy-three urinalyses were nitrite negative; 60 (82%) contained sensitive isolates. There was no statistically significant difference in the proportion of isolates sensitive to TMP/SMX. Thus, we conclude that emergency physicians should not adjust antibiotic therapy for UTI based on nitrite results.

Adult↗
PubMedDate not supplied

Five-week red cell storage with preservation of 2,3 DPG.

The 2,3 diphosphoglycerate (2,3 DPG) content of red cells stored in current anticoagulant-preservative products decreases rapidly after the first few days of storage, and by 3 weeks the red cells are essentially depleted of 2,3 DPG. Because ascorbic acid and ascorbate-2-phosphate (A-2-P) are effective in maintaining erythrocyte 2,3 DPG during liquid preservation, ascorbate was stabilized through autoclaving and subsequent storage by adding it as the trisodium salt of A-2-P to a phosphate-adenine-saline solution at a pH of 8.5 to 9.0. Red cell concentrates prepared from blood drawn into citrate-phosphate-double-dextrose were supplemented with the A-2-P additive solution (AS-4) and studied in vitro and in vivo. Mean 2,3 DPG values for 22 units were 147.6, 113.5, and 82.3 percent of initial value after storage for 3, 4, and 5 weeks, respectively. Maintenance of 2,3 DPG was at the expense of adenosine triphosphate (ATP), which fell to as low as 22.2 percent of initial value after 5 weeks. Despite the low ATP values, the 24 hour 51Cr-labeled red cell recoveries averaged 80.8 and 74.1 percent after 4 and 5 weeks of storage, respectively. The AS-4 system provides a red cell product with acceptable viability and improved oxygen off-loading function.

2,3-Diphosphoglycerate↗