Analgesics are an integral part of routine pain management in mammals, yet their use in fish is still limited. Some recommendations on the use of analgesics in fish are currently in the literature; however, information on the properties of analgesic drugs in most fish species is still scarce and sometimes misleading. The present review of information on the use of analgesics in fish was thus compiled to help clinicians make an informed decision as to which drug and dose to use. The main agents that have been investigated are opioids, NSAID, and local anesthetics, primarily in rainbow trout and zebrafish. There is presently no overwhelming evidence of efficacy for most analgesics in fish, although beneficial effects on behavior and physiologic parameters have been reported in many instances, especially associated with morphine administration. Furthermore, most analgesics did not result in significant adverse side effects. Thus, analgesics could be administered whenever it is considered that an animal might experience pain, given that the drugs appear not to cause harm and may be beneficial. However, caution must be advised because 1) important interspecies variation has been reported and 2) unforeseen effects could affect experimental results. Further research is needed to investigate analgesic use in fish. This should be accompanied by research aimed at improving our knowledge of the various species of fish. The current lack of a validated approach to assessing pain in fish limits our ability to evaluate the efficacy of analgesics in fish.

Capuchin monkeys are a species of arboreal primate found in all South American countries. These monkeys have been highlighted for their potential for biomedical research due to their anatomic and physiologic similarities and genetic homology with humans. Here we characterized the electrocardiographic tracings from 12 healthy, young capuchin monkeys that were restrained with ketamine and midazolam. All 12 monkeys had normal sinus rhythms. Neither P-wave duration, PR interval, QT interval, nor P- or R-wave amplitude (in millivolts) differed between males and females. The P waves were small, monophasic, and positive in all animals. The QRS complex showed positive polarity in the D1, D2, aVL, aVF, V2, V4, and V10 derivations and negative polarity in the D3, aVR, and rV2 leads. The T wave exhibited a negative polarity only in the aVR derivation in all animals in the study, and no significant difference was present between sexes. The ST segment was isoelectric in both sexes and lacked reductions and elevations. The anesthetic protocol was well tolerated all of the monkeys and allowed for diagnostic-quality acquisition, measurement, and characterization of the electrocardiogram and establishment of the normal electrocardiographic parameters of chemically restrained capuchin monkeys.

Time-weighted exposure limits to ammonia are established for humans; however similar guidelines have not been defined for laboratory rodents. The Guide recommends maintaining air pollutants at concentrations below levels irritating to mucous membranes but does not provide specific values. Numerous studies have examined ammonia and its effects on animal health, yet none have assessed the effects of naturally occurring intracage ammonia on the lower pulmonary tree and pulmonary endothelial and epithelial integrity in mice. We performed several assays commonly used in mouse acute lung-injury studies (bronchoalveolar lavage fluid [BAL] cell counts and protein concentration, excess lung water content [ELW], Evans blue permeability assay [EBA], lung tissue myeloperoxidase assay [MPO], and lung histopathology) to evaluate the effects of exposure to cyclical, naturally occurring ammonia levels on pulmonary integrity and inflammation. C57BL/6 mice were maintained in static microisolation or open-top cages. Cages were changed weekly, and ammonia levels were measured for 6 wk on days 0, 1, 3, 5, and 7 of each cage-change cycle. Ammonia levels in static microisolation cages began to increase on day 3 and peaked at a mean of 141.3 ppm on day 7. Ammonia levels in open-top cages never exceeded 5 ppm. Neither BAL cell counts, protein concentration, ELW, EBA, nor MPO differed significantly between groups. Lung histopathology showed minimal, incidental changes in all mice. Our findings indicate that the ammonia concentrations in the static microisolation cages we used did not alter the integrity of the lower pulmonary tract nor influence key indicators used to assess acute lung injury.

Smartphones are ubiquitous devices that offer a variety of useful applications for human and veterinary medical professionals and the biomedical research community. Smartphones can serve as fomites and potentially transmit pathogens, including bacterial species such as methicillin-resistant Staphylococcus aureus. The goal of this study was to evaluate 6 methods to decrease aerobic bacterial colonies on smartphones, including two 254-nm UVC devices, 70% ethanol spray, quaternary ammonium disinfectant spray, sodium hypochlorite-impregnated wipes, and delicate-task wipes. All methods were individually effective at decreasing aerobic bacterial counts after sanitization. In addition, 254-nm UVC devices providing a dose of 60 mJ/cm², with UVC bulbs exposing both sides of the smartphone, were an effective nonliquid method for smartphone sanitization.

All currently accepted methods of euthanasia for laboratory mice involve some degree of stress, fear, anxiety, or pain. We evaluated the voluntary oral administration of a euthanasia drug in 99 male and 81 female mice of various strains. We first explored the palatability of sugar-cookie dough with various flavorings added. We placed the cookie dough in the cage with an adult mouse and recorded the amount ingested after 1 h. Mice readily ingested all flavors of sugar-cookie dough. We then added a euthanasia solution containing pentobarbital and phenytoin to all flavors of cookie dough and placed a small bolus in the cage of each mouse or mouse pair. We observed the mice for 1 h for clinical signs of pentobarbital intoxication and then weighed uneaten dough to determine the dose of pentobarbital ingested. Palatability declined sharply when euthanasia solution was present. Mice ingested higher doses of pentobarbital in cookie dough during the dark phase and after fasting. Ingestion caused ataxia in some mice but was not sufficient to cause loss of righting reflex, unconsciousness, or death in any mouse. We successfully identified sugar cookie dough as a drug vehicle that was readily and rapidly eaten by mice without the need for previous exposure. Additional research is needed to identify euthanasia compounds for mice that do not affect the palatability of cookie dough.

This study presents recommendations for intramuscular injection into the caudal thigh muscle of mice according to analysis of in vivo imaging of intramuscularly injected iohexol, a radiocontrast agent commonly used in CT imaging. An experienced laboratory animal technician using a Hamilton syringe intramuscularly injected iohexol into isoflurane-anesthetized female and male BALB/c mice. Injected volumes (25, 50, 100, and 200 μL) underwent CT scanning at 9 time points over a 3-h period. The distribution of the injectate in the muscles of the rear leg was examined over time for each volume group. Results indicated that 25- and 50-μL volumes remain intramuscularly. At 100 μL, mild to moderate leakage into the extramuscular tissues occurred. At 200 μL, leakage into the extramuscular tissues was moderate to severe. Our results suggest volumes of 50 μL or less are recommended for the caudal thigh muscles of mice when intramuscular pharmacokinetics are needed; volumes greater than 50 μL display variable distribution into extramuscular tissues, thus potentially yielding different pharmacokinetic profiles.

Despite few published studies that assess the accuracy of glucometers in laboratory animals, glucometers are commonly used in animal research. We set out to determine the accuracy of 5 point-of-care glucometers (POCG) when used to evaluate murine whole blood, plasma, and serum samples. The POCG tested included one veterinary device (POCG A) and 4 humanuse instruments (POCG B through E). Whole blood, plasma, and serum samples from 50 female C57BL/6J mice were analyzed on all POCG, and serum was analyzed on a reference biochemical analyzer. The mean blood glucose concentration (BGC) measured in whole blood by using POCG A was greater than that on the biochemical analyzer, whereas the mean BGC in whole blood according to POCG B through E did not differ significantly from that on the biochemical analyzer. Mean BGC in plasma and serum did not differ between POCG B and E and the biochemical analyzer, whereas the plasma and serum BGC values from POCG C and D were greater than the mean BGC from the biochemical analyzer. The accuracy of each POCG for each sample type was evaluated by analyzing mean differences, correlations, and Bland–Altman graphs. We found that the 4 human-use POCG are appropriate for use with whole blood from female C57BL/6J mice, whereas only 2 of the evaluated POCG were sufficiently accurate for use with plasma or serum.

A common method for urine collection from rats requires the use of a metabolic cage, thus exposing animals to extended periods of isolation in an unfamiliar cage with a wire-mesh floor. A new method involving hydrophobic sand, a material more similar to bedding, has become available recently but has not been extensively compared with metabolic cages in regard to collection efficiency or stress. Using a within-subjects crossover design, we examined differences in stress markers, urinary markers, and urine volume of clinically healthy male Sprague–Dawley rats during 2-, 4-, and 6-h collection sessions in hydrophobic sand and metabolic cages. Stress response markers of weight loss, fecal pellet output, or corticosterone did not differ between hydrophobic sand and metabolic cages, and observed behavior suggested that sand may be less stressful than metabolic cages. All clinically relevant urinary markers examined were normal, with no differences between collection methods. Total urine volume collected was greater from the metabolic cage than sand in 3 of the 5 sessions, but the volume collected during the shortest session (2 h) did not differ between methods and accounted for 62% of the total volume collected during the longest session (6 h). Our results suggest that hydrophobic sand is a refinement of urine collection methods for rats that decreases isolation time, risk of injury, and stress and maintains the integrity of urine samples.

Despite increased use of zebrafish (Danio rerio) in biomedical research, consistent information regarding appropriate euthanasia methods, particularly for embryos, is sparse. Current literature indicates that rapid cooling is an effective method of euthanasia for adult zebrafish, yet consistent guidelines regarding zebrafish younger than 6 mo are unavailable. This study was performed to distinguish the age at which rapid cooling is an effective method of euthanasia for zebrafish and the exposure times necessary to reliably euthanize zebrafish using this method. Zebrafish at 3, 4, 7, 14, 16, 19, 21, 28, 60, and 90 d postfertilization (dpf) were placed into an ice water bath for 5, 10, 30, 45, or 60 min (n = 12 to 40 per group). In addition, zebrafish were placed in ice water for 12 h (age ≤14 dpf) or 30 s (age ≥14 dpf). After rapid cooling, fish were transferred to a recovery tank and the number of fish alive at 1, 4, and 12–24 h after removal from ice water was documented. Euthanasia was defined as a failure when evidence of recovery was observed at any point after removal from ice water. Results showed that younger fish required prolonged exposure to rapid cooling for effective euthanasia, with the required exposure time decreasing as fish age. Although younger fish required long exposure times, animals became immobilized immediately upon exposure to the cold water, and behavioral indicators of pain or distress rarely occurred. We conclude that zebrafish 14 dpf and younger require as long as 12 h, those 16 to 28 dpf of age require 5 min, and those older than 28 dpf require 30 s minimal exposure to rapid cooling for reliable euthanasia.

Blood pressure is a critical parameter for evaluating cardiovascular health, assessing effects of drugs and procedures, monitoring physiologic status during anesthesia, and making clinical decisions. The placement of an arterial catheter is the most direct and accurate method for measuring blood pressure; however, this approach is invasive and of limited use during brief sedated examinations. The objective of this study was to determine which method of indirect blood pressure monitoring was most accurate compared with measurement by direct arterial catheterization. In addition, we sought to determine the relative accuracy of each indirect method (compared with direct arterial measurement) at a given body location and to assess whether the accuracy of each indirect method was dependent on body location. We compared direct blood pressure measurements by means of catheterization of the saphenous artery with oscillometric and ultrasonic Doppler flow detection measurements at 3 body locations (forearm, distal leg, and tail base) in 16 anesthetized, male rhesus macaques. The results indicate that oscillometry at the forearm is the best indirect method and location for accurately and consistently measuring blood pressure in healthy male rhesus macaques.