Nephrogenic systemic fibrosis, in patients with end-stage kidney disease on dialysis, in the greater Auckland region, from 2000-2006.

AIM: Nephrogenic systemic fibrosis (NSF) is a rare and serious disease characterised by thickening and hardening of the skin with fibrosis of the dermis with CD34-positive fibrocytes. NSF occurs in patients with renal failure and has been linked to exposure of gadolinium contrast agents. The Auckland region has a population of 1.3 million with consultation and dialysis services for patients with end stage kidney disease provided by two separate renal units. The aim of this study was to determine the incidence and frequency of NSF in the Auckland region and determine the risk based on exposure to gadolinium based contrast agents. METHODS: A retrospective case notes review of all patients with end stage kidney disease under the care of the renal services between 1(st) January 2000 and 31(st) December 2006 was undertaken. All cases of proven or suspected NSF were identified. Using a picture archive and communications support system all imaging and exposure to contrast was identified. RESULTS: Three cases of biopsy proven NSF and two further cases of clinical NSF were identified. In all cases there was exposure to Gadolinium. This risk of NSF on exposure to any gadolinium based contrast agents was 0.67%. Gadodiamide was used in one institution where all five cases of NSF were seen, gadodiamide was used in 1% of patients in the other institution with no recognised cases. CONCLUSION: The incidence of NSF is low with the greatest risk on exposure to linear, non-ionic chelates, with no ethnic predisposition.

Omeprazole-induced acute interstitial nephritis is not related to CYP2C19 genotype or CYP2C19 phenotype.

AIM: Omeprazole-induced acute interstitial nephritis (OIAIN) is a rare adverse event. It is unknown if this is an idiosyncratic immune mediated reaction or if it relates to direct drug toxicity. Individuals who are homozygous for the variant alleles of CYP2C19 are poor metabolizers of omeprazole and have a greater exposure to the drug. The aim of this study was to determine the prevalence of the CYP2C19 poor metabolizer genotype and phenotype in patients with OIAIN. METHODS: Twenty patients were genotyped for the CYP2C19 variant alleles (2, 681G>A and 3, 636G>A) by RFLP-PCR analysis and eighteen phenotyped for CYP2C19 metabolizer status. RESULTS: The frequency of the CYP2C19 2 allelic variant was 12.5%, no 3 allelic variants were detected and no patient was a homozygous variant genotype. This was not different from the expected frequency. 33% of subjects were phenotypically CYP2C19 poor metabolizers. CONCLUSIONS: There was discordance between CYP2C19 genotype and phenotype. However, up to 45% of healthy elderly subjects have a poor metabolizer phenotype. Thus neither CYP2C19 poor metabolizer genotype nor phenotype is a risk factor for OIAIN.

Caffeine effects on physical and cognitive performance during sustained operations.

PURPOSE: This study examined caffeine (CAF) effects on physical performance and vigilance during 4 d and 3 nights of sustained operations in Special Forces personnel. METHODS: There were 20 soldiers (28.6 +/- 4.7 yr, 177.6 +/- 7.5 cm, 81.2 +/- 8.0 kg) who were divided equally into placebo (PLAC) and CAF groups. A 4-km run that included three obstacles (OBST) was completed each morning with the performance on Day 2 representing control (CON) after familiarization on Day 1 and an 8-h sleep. From 01:30 to 06:15 of Days 3-5, soldiers performed two 2-h vigilance (VIG) sessions in the field. PLAC or 200 mg of CAF was administered at 21:45 of Days 2-4 and at 01:00, 03:45, and approximately 07:00 on Days 3-5. The run commenced within 30 min of the final dose. Soldiers were provided a 4-h sleep period from 13:30-17:30 during Days 3 and 4. RESULTS: VIC during Days 3-5 was greater for CAF vs. PLAC and not different from CON. Total run time was faster for CAF (29.7 +/- 2.0 min) compared with PLAC (30.7 +/- 2.9 min) on Day 3 due to faster completion of OBST (8.7 +/- 0.7 min vs. 9.2 +/- 1.0 min for CAF and PLAC, respectively). Thereafter, run times decreased for both groups on Days 4 and 5 compared with CON due primarily to an increased pace between OBST. CONCLUSIONS: it was concluded that CAF maintained both vigilance and physical performance during sustained operations that require periods of overnight wakefulness and restricted opportunities for daytime sleep.

Caffeine maintains vigilance and improves run times during night operations for Special Forces.

PURPOSE: This study examined the effects of caffeine (CAF) on vigilance, marksmanship, and run performance during 27 h of sustained wakefulness in Special Forces personnel. METHODS: There were 31 soldiers (29.8 +/- 5.4 yr, 86.4 +/- 8.6 kg) who were divided into placebo (PLAC, n = 15) and CAF (n = 16) groups. A 6.3-km control run was completed on the morning of Day 1. In the evening of Day 2, soldiers performed a control observation and reconnaissance vigilance task (ORVT) in the field. This 90-min task was repeated twice more between 02:00 and 06:00 on Day 3 during an overnight period of sleep deprivation. Marksmanship was assessed before and after the ORVT. PLAC or 200 mg of CAF gum was administered at 01:45, 03:45, and approximately 06:30 on Day 3. A final 6.3-km run commenced within 30 min of receiving the final dose. RESULTS: ORVT was maintained in CAF at control levels of 77 +/- 13% during the overnight testing. However, values decreased significantly for PLAC from 77 +/- 15% to 54 +/- 29% and 51 +/- 31% during the first and second overnight testing periods, respectively. CAF had no effect on marksmanship but improved 6.3-km run times by 1.2 +/- 1.8 min. Run times slowed for PLAC by 0.9 +/- 0.8 min from approximately 35 min during the control run; the changes in performance were significant between groups. CONCLUSIONS: It was concluded that CAF maintained vigilance and improved running performance during an overnight field operation for Special Forces personnel.

Caffeine improves reaction time, vigilance and logical reasoning during extended periods with restricted opportunities for sleep.

RATIONALE: Various occupational groups are required to maintain optimal physical and cognitive function during overnight periods of wakefulness, often with less than optimal sleep. Strategies are required to help mitigate the impairments in cognitive function to help sustain workplace safety and productivity. OBJECTIVES: To test the effectiveness of repeated 200 mg doses of caffeine on cognitive function and live-fire marksmanship with soldiers during three successive nights of sustained wakefulness followed by 4-h afternoon sleep periods. METHODS: Twenty Special Forces personnel (28.6 ± 4.7 years, 177.6 ± 7.5 cm and 81.2 ± 8.0 kg) were randomly assigned to receive four 200-mg doses of caffeine (n = 10) or placebo (n = 10) during the late evening and early morning hours during three successive days. An afternoon 4-h sleep period followed. The psychomotor (PVT) and field (FVT) vigilance, logical reasoning (LRT) tests and a vigilance monitor assessed cognitive function throughout the study. Live-fire marksmanship requiring friend-foe discrimination was assessed. RESULTS: Caffeine maintained speed on the PVT (p < 0.02), improved detection of events during FVT (p < 0.001), increased number of correct responses to stimuli as assessed by the vigilance monitor (p < 0.001) and increased response speed during the LRT (p < 0.001) throughout the three overnight testing periods. Live-fire marksmanship was not altered by caffeine. CONCLUSIONS: A total daily dose of 800 mg caffeine during successive overnight periods of wakefulness is an effective strategy to maintain cognitive function when optimal sleep periods during the day are not available.