Utilization of D-ribitol by Lactobacillus casei BL23 requires a mannose-type phosphotransferase system and three catabolic enzymes.

Lactobacillus casei strains 64H and BL23, but not ATCC 334, are able to ferment D-ribitol (also called D-adonitol). However, a BL23-derived ptsI mutant lacking enzyme I of the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) was not able to utilize this pentitol, suggesting that strain BL23 transports and phosphorylates D-ribitol via a PTS. We identified an 11-kb region in the genome sequence of L. casei strain BL23 (LCABL_29160 to LCABL_29270) which is absent from strain ATCC 334 and which contains the genes for a GlpR/IolR-like repressor, the four components of a mannose-type PTS, and six metabolic enzymes potentially involved in D-ribitol metabolism. Deletion of the gene encoding the EIIB component of the presumed ribitol PTS indeed prevented D-ribitol fermentation. In addition, we overexpressed the six catabolic genes, purified the encoded enzymes, and determined the activities of four of them. They encode a D-ribitol-5-phosphate (D-ribitol-5-P) 2-dehydrogenase, a D-ribulose-5-P 3-epimerase, a D-ribose-5-P isomerase, and a D-xylulose-5-P phosphoketolase. In the first catabolic step, the protein D-ribitol-5-P 2-dehydrogenase uses NAD(+) to oxidize D-ribitol-5-P formed during PTS-catalyzed transport to D-ribulose-5-P, which, in turn, is converted to D-xylulose-5-P by the enzyme D-ribulose-5-P 3-epimerase. Finally, the resulting D-xylulose-5-P is split by D-xylulose-5-P phosphoketolase in an inorganic phosphate-requiring reaction into acetylphosphate and the glycolytic intermediate D-glyceraldehyde-3-P. The three remaining enzymes, one of which was identified as D-ribose-5-P-isomerase, probably catalyze an alternative ribitol degradation pathway, which might be functional in L. casei strain 64H but not in BL23, because one of the BL23 genes carries a frameshift mutation.

Iterative reconstruction methods for nonuniform attenuation distribution in SPECT.

Two iterative methods, a generalization of the Chang method and a projection precorrection, were investigated to determine whether the use of an attenuation map could improve nonuniform attenuation compensation. After a detailed description of the methods, results obtained with simulated and phantom data were compared. This study demonstrates that projection precorrection provides accurate quantification and good image quality as early as the precorrection step, whereas the generalized Chang method requires computation of one more iteration.

Third-degree burns due to intraoperative use of a Bair Hugger warming device.

We report the case of a 3-year-old boy who underwent correction of transposition of the great arteries who developed burns from use of a patient warming device. His repair had been delayed because he was from a developing country, and he was offered surgery as part of a humanitarian effort. Postoperatively he was noted to have second- and third-degree burns from use of a Bair Hugger (Augustine Medical, Eden Prairie, MN) warming system after cardiopulmonary bypass.

Neonatal subcapsular hematoma of the liver presenting as an abdominal mass. Report of two cases.

Two infants with hepatic subcapsular hemmorrhage presenting as abdominal masses at age 17 days and 49 days are reported. The first had a slowly progressive course and the second had initial internal bleeding. Aortography assisted in the management of the second case.

Stridor in pediatric patients.

We have presented a classification scheme to help in evaluating the diagnosis of stridor in the pediatric patient. The correct diagnosis can usually be arrived at on the basis of a careful and complete history, physical examination, appropriate radiographic studies and bronchoscopy. The anesthesiologist should be aware of the problems associated with all these conditions. In every instance prompt establishment of an adequate airway is imperative.

Successful reversal of brain damage from iatrogenic air embolism.

During an aortocoronary bypass procedure, the patient suffered an air embolism arising from technical difficulties with the extracorporeal circulatory device. Initial emergency treatment included a loading dose of thiopental concomitant to a one hour period profound hypothermia. A modified protocol for treating patients with acute head injuries was the initiated. It combined moderate hypothermia with continuous barbiturate coma for 96 hours. Brain activity in this patient returned on the third postoperative day. She recovered completely, with no detectable neurologic damage.