Flow cytometric analysis of hepatopancreatic cells from Armadillidium vulgare highlights terrestrial isopods as efficient environmental bioindicators in ex vivo settings

Several studies have reported the high bioindication capacity of Isopoda (Crustacea, Oniscidea), which is related to their important ability to accumulate contaminants, usefulness in soil ecotoxicology and bioindication activities. Any change in the isopod population, diversity and life cycle can indicate relevant pollution levels. The analysis of target tissues, such as the hepatopancreas, is another emerging approach (from a cytologic/histological level) to detect contaminant accumulation from different sources. In this study, tissue disaggregation procedures were optimised in the hepatopancreas, and flow cytometry (FC) was applied to detect cell viability and several cell functions. After disaggregation, two hepatopancreatic cell types, small (S) and big (B), were still recognisable: they differed in morphology and behaviour. The analyses were conducted for the first time on isopods from sites under different conditions of ecological disturbance through cytometric re-interpretation of ecological-environmental parameters. Significant differences in cell functional parameters were found, highlighting that isopod hepatopancreatic cells can be efficiently analysed by FC and represent standardisable, early biological indicators, tracing environmental-induced stress through cytologic/histologic analyses.

Biologic monitoring and causes of failure in cycles of sterilization in dental care offices in Mexico

BACKGROUND

Biologic indicator tests (BIs) are considered the most meaningful way to verify sterilization.

OBJECTIVE

To monitor the cycles of sterilization using BIs in dry heat sterilizers and steam autoclaves and to identify the causes of failures in the cycles of sterilization in dental offices in San Luis Potosí, México.

METHODS

An invitation to participate was sent to 400 dental offices, and 206 practitioners of 200 dental offices were included. A questionnaire was given to each of the participants, asking for the following information: sterilizer type, operational parameters used (eg, temperature, pressure, and length of exposure), frequency of sterilization cycles per day, use of BIs, and maintenance procedures of the sterilizer. Two hundred thirty sterilizers were monitored using BIs. The sterilizers with positive results were monitored a second and third time to identify the cause of the failure.

RESULTS

Twenty-two percent of practitioners (n = 46) used BIs, and 17% (n = 39) of the sterilizers reported positive results (bacterial growth). The detected failures were a mistake in the procedure (eg, temperature, time, or pressure), an absence of supervision of the procedure performed by the assistant, and improper maintenance.

CONCLUSIONS

There are opportunities to increase information on infection control, to improve the adoption of standard quality control methods for sterilization as a routine process, to improve training on proper testing, and standardize processes.