Variation in detection limits between bacterial growth phases and precision of an ATP bioluminescence system.

UNLABELLED: To determine the detection limits of the SystemSure Plus, Escherichia coli and Staphylococcus aureus growth curve samples were taken in lag (1 h), log (6 h), stationary (12 h) and death phases (E. coli 144 h, Staph. aureus 72 h). At each time point, the log10 CFU ml(-1) was determined for the dilution where the SystemSure read 0 relative light units (RLU). Average detection limits were E. coli: lag 6·27, log 5·88, stationary 7·45 and death 6·88; Staph. aureus: lag 4·37, log 5·15, stationary 7·88 and death 7·57. Between-run precision was determined with positive control; within-run precision with positive control, lag and log growth for each bacteria. Within-run precision mean RLU (CV): positive control 274 (12%), E. coli lag 1 (63%), log 2173 RLU (19%), Staph. aureus lag 2 (58%) and log 5535 (18%). Between-run precision was 232 (16%). The precision is adequate with most values within the 95% confidence interval. The detection limit varied by 3·51 log10 for Staph. aureus and 1·47 log10 for E. coli. The lowest detection limits were during E. coli log and Staph. aureus lag phases; the highest was during stationary phase. These results suggest that organism identification and growth phase both impact ATP RLU readings. SIGNIFICANCE AND IMPACT OF THE STUDY: Surface hygiene is a critical component of food safety and infection control; increasingly, ATP detection by bioluminescence is used to evaluate surface hygiene and effective cleaning. This is the first study to show that the number of living and potentially infectious bacteria remaining when the device reads zero varies between the different bacterial life cycle phases: lag, log, stationary and death. ATP device users need to be aware of this information to use the devices appropriately.

The management of patients with attention-deficit hyperactivity disorder by family practitioners.

BACKGROUND: The objective of this study was to describe the practices of family practitioners in Missouri in the treatment of patients with ADHD. METHOD: The 634 Diplomats of the American Board of Family Practice of Missouri were surveyed. RESULTS: Respondents considered stimulant medication to be effective treatment for ADHD; methylphenidate was the drug of choice. Most respondents (79%) reported recommending behavioral management to parents. Reported efficacy of stimulants (item 2) and use of behavior management (item 8) were related in the negative direction, while reported efficacy of stimulants and using stimulants alone (item 13) were related in the positive direction. CONCLUSIONS: Family practitioners in Missouri used accepted treatments for ADHD, but in general, practices were not entirely consistent with the current standard of care. Physicians' belief in the efficacy of stimulants may have prejudiced them against multimodal treatment.

Results of blood lead screening in children referred for behavioral disorders.

This study reviews findings from blood lead level screening in children referred to an Attention Deficit Hyperactivity Disorder clinic. Results obtained from 102 children revealed a sample mean blood lead level of 2.29 micrograms/dL and one patient with a mildly elevated blood lead level. Comparing these findings to results of national studies suggests that these children are not at higher risk for elevated lead levels than is the average child living in a similar setting.

Paroxysmal nocturnal hemoglobinuria associated with infectious mononucleosis.

A previously healthy 16-yr-old girl was found to have pancytopenia, low reticulocyte count, a cellular bone marrow, and a negative Coombs test, all coincident with clinical and laboratory evidence of infectious mononucleosis. Symptoms and signs of infectious mononucleosis subsided, but pancytopenia and hemolytic anemia persisted. Sucrose hemolysis and acid hemolysis tests supported a diagnosis of paroxysmal nocturnal hemoglobinuria (PNH). After 18 mo, the platelet count is normal, but leukopenia and hemolytic anemia continue. The development of PNH in this patient suggests it may have resulted from an effect of infectious mononucleosis.

Phase I study of thymidine plus 5-fluorouracil infusions in advanced colorectal carcinoma.

In order to determine the minimal toxic dose of a 5-day infusion of 5-fluorouracil (5--FU) in combination with an infusion of thymidine (TdR), 12 patients, received TdR at a dose of 8 g/m2/day for 5 1/2 days, beginning at the same time as a 5-day infusion of 5-FU at doses of 5--20 mg/kg/day. Myelosuppression was the dose-limiting toxicity, and the minimal toxic dose of 5--FU was found to be 7.5 mg/kg/day. Gastrointestinal toxicity was minimal to absent. In eight patients with carcinoma of the colon who had received no prior chemotherapy, there were two patients with partial responses (at doses of 5.0 and 7.5 mg/kg/day of 5--FU), two patients with stable disease, one patient with progressive disease, and three patients with early death (two drug-related deaths and one disease-related death). In four patients who had received prior 5--FU, one had stable disease, one had progressive disease, and two had early death (one drug-related death). We conclude that the addition of TdR to 5--FU infusions changes the dose-limiting toxicity from gastrointestinal toxicity to myelosuppression. The minimal toxic dose is decreased to approximately one third of that when 5--FU is administered alone.