Prevalence of positive microbiology results from donor cornea tissue in different methods of corneal transplantation.

PURPOSE: To evaluate the prevalence of positive microbiology results (culture and/or Gram stain) in donor cornea tissue with newer transplant methods and to assess if the results subsequently correlate with higher incidence of clinical infection. METHODS: A retrospective review of the microbiology records of 569 consecutive corneal transplants from July 2006 through July 2010 was performed to evaluate positive microbiology results in routine evaluation of cornea donor tissue. RESULTS: Microbiologic results were available for 544 of 569 transplants. The remaining 25 cases did not have specimens submitted for microbiologic analysis. In cases with results available, 46 (8.5%) positive reports occurred. In 10 of the 46 cases, Gram stain results were positive with subsequent negative cultures. Analysis revealed that the prevalence of positive results was 6 in 137 (4.4%), 14 in 127 (11.0%), and 26 in 271 (9.6%) for femtosecond laser-enabled keratoplasty, Descemet stripping automated endothelial keratoplasty, and conventional penetrating keratoplasty, respectively; 9 femtosecond deep anterior lamellar keratoplasty had no positive results. There was no significant relationship between the types of transplant procedures and the occurrence of positive microbiologic results (P = 0.08). The overall incidence of clinical infection was found to be 0.4% (2 of 569); however, only 1 case (1 of 569 or 0.2%), which was a Candida albicans infection after Descemet stripping automated endothelial keratoplasty, was attributable to the donor. Of 25 cases in which microbiology studies were not performed, none developed a clinical infection. CONCLUSIONS: Prevalence of positive microbiologic results and subsequent infections do not appear to be increased with the method of donor handling used for newer techniques for keratoplasty.

Sleep deprivation in rats produces attentional impairments on a 5-choice serial reaction time task.

STUDY OBJECTIVES: To develop a rodent model of the attentional dysfunction caused by sleep loss. DESIGN: The attentional performance of rats was assessed after 4, 7, and 10 hours of total sleep deprivation on a 5-choice serial reaction time task, in which rats detect and respond to brief visual stimuli. SETTING: The rats were housed, sleep deprived, and behaviorally tested in a controlled laboratory setting. PARTICIPANTS: Ten male Long-Evans rats were used in the study. INTERVENTIONS: Rats were trained to criteria and subsequently tested in daily sessions of 100 trials at approximately 4:00 PM (lights on 8:00 AM-8:00 PM). Attentional performance was measured after 4, 7, 10 hours of total sleep deprivation induced by gentle handling. RESULTS: Sleep deprivation produced a monotonic increase in response latencies across the 4-hour, 7-hour, and 10-hour deprivations. Sleep deprivation also led to increased omission errors, but the overall number of perseverative and premature responses was unchanged. Subgroups of rats were differentially affected in the number of omission errors and perseverative responses. CONCLUSIONS: The effects of sleep deprivation on rats are compatible with a range of human findings on the effects of sleepiness on selective attention, psychomotor vigilance, and behavioral control. Rats also exhibited differential susceptibility to the effects of sleep deprivation, consistent with 'trait-like' susceptibility that has been found in humans. These findings indicate the feasibility of using the 5-choice serial reaction time task as an animal model for investigating the direct links between homeostatic sleep mechanisms and resulting attentional impairments within a single animal subject.