Establishing Digital Biomarkers for Occupational Health Assessment in Commercial Salmon Fishermen: Protocol for a Mixed-Methods Study

Background

Commercial salmon fishing in Alaska is one of the most dangerous occupations in the United States. Between 1992 and 2008, the average annual industry mortality rate was 128 deaths per 100,000 workers, and despite an increase in industry regulations, there has not been a significant decrease in mortality rate since 2000. Unpredictable fishing openings and fierce competition for limited resources result in periods of intense sleep deprivation and physical strain during the short commercial salmon season in Alaska.

Objective

We hypothesize that the combined effect of sleep deprivation, intense physical workload, and significant short-term chronic stress may be deleterious to health in both the short- and long-term among commercial salmon drift gillnet fishermen in Alaska. The objective of this protocol is to determine the feasibility of the study design to test this hypothesis.

Methods

The study design uses mixed methods and includes biometric monitoring consisting of heart rate variability, respiration, and movement data collected via a personal, wearable biometric device. Additional methods include observational data on activity, including duration and quality of sleep, weather, catch, and financial gain, as well as the collection of salivary cortisol. As such, the study will provide a holistic assessment of individual stress on multiple simultaneous timescales: immediately and continuously through the personal wearable biometric device, on the minute-hour level through the multiple daily collections of salivary cortisol, and by the hour-day through the use of participant and environment observational data.

Results

Data collection was initiated in July 2017 and will extend through August 2019. Initial data collection has indicated that the methods outlined in this protocol are feasible and allow for effective collection of qualitative and quantitative data related to the psychological and physiological impact of Alaska commercial salmon fishing.

Conclusions

We anticipate that the use of a biometric device will be crucial in establishing measures of stress and physical activity within a population and environment uniquely challenged by physical isolation, strong weather patterns, and the potential for significant financial gain by fishermen. The potential exists for individuals engaged long-term in the fishing industry, through repeated and extended exposure to periods of intense sleep deprivation and chronic stress, to be at increased risk of cardiovascular disease.

International Registered Report Identifier (IRRID)

DERR1-10.2196/10215

Malassezia otitis externa in the dog: the effect of heat-fixing otic exudate for cytological analysis

This study was conducted on 32 dogs with Malassezia otitis externa to determine the effect of heat-fixing otic exudate on cytological analysis. Malassezia infection was confirmed by cytological examination of otic exudate. Otic discharge collected with cotton swabs was then rolled onto glass slides. One slide per dog was heat-fixed prior to staining; the other slide was not heat-fixed. The number of yeast in 10 oil-immersion fields (1000 x magnification) was counted for both slides from each dog. Heat-fixing did not systematically cause either increased or decreased numbers of Malassezia on cytology of otic exudate.

Evaluation of the pharmacokinetics and pharmacodynamics of intravenous lansoprazole

AIM

To compare the pharmacokinetics and pharmacodynamics of lansoprazole 30 mg administered intravenously in 0.9% NaCl or in polyethylene glycol, or orally.

METHODS

Twenty-nine subjects received lansoprazole orally on days 1-7 and intravenous lansoprazole in NaCl on days 8-14. Blood samples were collected on days 1, 7, 8 and 14. Fasting basal acid output and pentagastrin-stimulated maximal acid output were determined on days -1, 8, 9 and 15. Thirty-six different subjects received one of four regimen sequences: intravenous lansoprazole in NaCl, intravenous in polyethylene glycol, per orally, or intravenous placebo, each for 5 days. Twenty-four hour intragastric pH was recorded on days 1 and 5.

RESULTS

Intravenous and per oral lansoprazole for 7 days produced equivalent basal acid output and maximal acid output suppression. Pharmacokinetics and mean pH values with intravenous lansoprazole in NaCl or polyethylene glycol were equivalent. Both produced mean pH and percentages of time pH above 3, 4, 5 and 6 that were significantly greater than did per orally.

CONCLUSIONS

Intravenous lansoprazole inhibits acid secretion as effectively in NaCl as in polyethylene glycol, and its onset of action is faster than per oral lansoprazole.

Comparative pharmacokinetics and pharmacodynamics of lansoprazole oral capsules and suspension in healthy subjects

The pharmacokinetics and pharmacodynamics of lansoprazole suspension and lansoprazole capsules were studied. Thirty-six healthy males and females were randomized in a single-dose, open-label, two-period crossover study. Lansoprazole 30 mg was administered via a nasogastric tube as simplified lansoprazole suspension (in 8.4% sodium bicarbonate) or orally as the intact capsule after a minimum 12-hour fast and 5 hours before lunch. Ambulatory 24-hour intragastric pH was monitored at baseline and on day 1 of each treatment period to assess lansoprazole's pharmacodynamics. Blood samples were collected before drug administration and at predetermined intervals up to 24 hours after each dose to assess lansoprazole's pharmacokinetics. Both formulations effectively raised the mean 24-hour intragastric pH (mean 24-hour pH of 3.75 with suspension and 3.52 with intact capsule) and maintained it above threshold values of 3 and 4 for more than 40% of the 24-hour postdose period. The suspension was associated with a significantly shorter mean time to the maximum observed concentration (tmax) compared with the intact capsule. The mean maximum observed plasma concentration (Cmax) of the suspension was significantly higher and the mean area under the concentration-time curve from time zero to infinity (AUC infinity) was significantly lower than those of the intact capsule (879 versus 810 ng/mL and 1825 versus 2229 ng.hr/mL). The 90% confidence intervals obtained by two one-sided tests for both Cmax and AUC infinity were contained within the 0.80 to 1.25 range, confirming the bioequivalence of the two regimens. Simplified lansoprazole suspension effectively controls intragastric pH, is bioequivalent to the intact capsule, and represents an effective therapeutic option for patients who have difficulty swallowing or are unable to swallow lansoprazole capsules.