Journal Of The American Association For Laboratory Animal Science[JOURNAL]
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200 papers
Medetomidine Administration at the Subcutaneous GV20 Acupoint Compared with the Intramuscular Route in Guinea Pigs (Cavia porcellus): Sedation Score, Onset, and Duration of Action.
Esjaita EI, Fuensalida SE, Giansanti NH … +5 more , Regner PI, Bernal LD, García-Blanco F, Otero PE, Waxman S
J Am Assoc Lab Anim Sci · 2026 May · PMID 42134808 · Full text
Recent research in both humans and animals has explored alternative routes for drug administration, such as pharmacopuncture, a technique involving the subcutaneous administration of low drug doses at acupuncture points....
Recent research in both humans and animals has explored alternative routes for drug administration, such as pharmacopuncture, a technique involving the subcutaneous administration of low drug doses at acupuncture points. Among these points, the Governing Vessel 20 (GV20) has attracted particular interest in veterinary medicine due to its reported tranquilizing and sedative effects in humans and dogs. It has been proposed that administering sedative agents at this site may potentiate their effects, allowing for dose reduction while maintaining efficacy and minimizing adverse reactions. This study aimed to compare the sedative effects of medetomidine administered at the GV20 acupoint compared with the intramuscular route in adult guinea pigs (Cavia porcellus). Twenty animals received medetomidine (100 µg/kg) via both routes in a crossover design with a 2-week washout period. Sedation was assessed using a previously published scale (0-19). Sedation onset was defined as the time to achieve a score >3 of 19, and duration as the time to return to ≤3 of 19. Assessments were performed before and after administration at 1-minute intervals for the first 10 minutes, then every 2 minutes up to 30 minutes, and every 5 minutes thereafter until recovery. Comparisons of maximum sedation score, onset, and duration between routes were analyzed using the Wilcoxon signed-rank test. No significant differences were found in the maximum score, time to onset, or duration of sedation between the GV20 and intramuscular routes. These results indicate that, under the conditions of this study, medetomidine administration at GV20 did not enhance sedative efficacy or prolong the duration of action compared with the intramuscular route.
Letter to the Editor.
Guarnieri M
J Am Assoc Lab Anim Sci · 2026 May · PMID 42128428 · Full text
Abstract loading — click title to view on PubMed.
Mtb-Specific Interferon-Gamma ELISpot Assays Have Greater Sensitivity for Detecting Mtb Infection Compared to Tuberculin Skin Test in a Cohort of Experimentally M. tuberculosis-Infected Macaques.
Malin MA, Maiello P, Borish HJ … +15 more , Fillmore D, Tomko J, Kracinovsky K, Schober J, Mattila J, Klein EC, Trichel AM, Skorupski A, Geddedu-Hurdial JR, Narainapoullé S, Rodgers M, Walker R, Flynn JL, Scanga CA, Lin PL
J Am Assoc Lab Anim Sci · 2026 May · PMID 42128427 · Publisher ↗
Tuberculosis outbreaks in nonhuman primate (NHP) colonies can result in disastrous financial, scientific, animal welfare, and public health outcomes. Tuberculin skin testing (TST) has been the standard diagnostic method...
Tuberculosis outbreaks in nonhuman primate (NHP) colonies can result in disastrous financial, scientific, animal welfare, and public health outcomes. Tuberculin skin testing (TST) has been the standard diagnostic method for identifying Mycobacterium tuberculosis (Mtb) infection in NHPs but has limited sensitivity and specificity. In humans, Mtb-specific interferon-γ release assays (IGRAs) have become the preferred diagnostic method, overcoming significant limitations of the TST. We compared the diagnostic qualities of the TST and IGRA in a cohort of 673 rhesus and cynomolgus macaques with experimental Mtb infection. Serial TST and IGRA data were curated retrospectively for animals before and after Mtb infection and temporally matched to assess sensitivity, specificity, and agreement between the 2 tests. The overall sensitivity of the IGRA was 0.84 compared with 0.49 sensitivity of the TST test in detecting Mtb infection. Specificity of the IGRA and the TST was 0.83 and 1.0, respectively, with an overall agreement rate of 72% between the 2 tests. Sensitivity peaked at 3-5 weeks postinfection for TST and 5-7 weeks for IGRA. Data from a second cohort of animals (n = 227) that were not experimentally infected with Mtb, but for whom testing was done for screening and investigational purposes, demonstrated an agreement rate of 96%. To our knowledge, this is the largest reported comparison of TST and IGRA testing in NHPs. Although IGRAs are more labor intensive than TSTs, our data suggest that IGRAs have better diagnostic accuracy in detecting Mtb infection. Our data also suggest that the threshold for a positive TST could be lowered to improve sensitivity.
Aquatic Advancements: Refining and Validating a Zebrafish Survival Blood Collection Technique.
Rehman F, Murray C, Luchins KR … +4 more , Felgenhauer JL, Remmers G, Langan GP, Mailhiot D
J Am Assoc Lab Anim Sci · 2026 May · PMID 42106165 · Full text
The zebrafish (Danio rerio) has become a cornerstone model organism for studying vertebrate development, human diseases, drug discovery, and toxicology. A key challenge in leveraging this model lies in the need for repea...
The zebrafish (Danio rerio) has become a cornerstone model organism for studying vertebrate development, human diseases, drug discovery, and toxicology. A key challenge in leveraging this model lies in the need for repeatable, nonlethal blood sampling, essential for longitudinal studies. Due to the aquatic environment, lack of easily accessible vasculature, small size, and blood volume of this species, blood sampling of zebrafish presents a unique set of biologic, technical, and logistical challenges. Despite advancements, standardized survival blood collection protocols for zebrafish remain underdeveloped. We refined and validated a survival blood collection methodology using the dorsal aorta as an accessible vascular site. We used anesthetized fish, precise glass pipette creation for microscale blood draws, and the adoption of safe capillary collection techniques, enabling the ability to perform blood collection weekly for up to 4 weeks. Both male and female zebrafish were evaluated to account for potential sex-based differences, enhancing reproducibility and translational relevance. Hemoglobin (Hgb) levels were monitored as a biomarker of anemia, alongside behavioral and clinical assessments. Histopathological analyses showed no significant differences in tissue response between 1 and up to 4 blood draws. Hgb values decreased proportionately to increasing blood collection volumes, while behavioral and clinical assessments revealed no observable detriment even at higher blood volumes. This study presents a validated and standardized application of previously described survival blood collection techniques, demonstrating the feasibility of repeated sampling over 4 weeks while incorporating behavioral and histopathologic outcome measures relevant to clinical tolerance and longitudinal study design, thus continually broadening zebrafish utility in preclinical research.
Incidence of Spontaneous Ocular Lesions in Laboratory Animals.
Cheng H, Gao J, Zhou Y
J Am Assoc Lab Anim Sci · 2026 May · PMID 42106164 · Full text
The purpose of this study was to establish a database of spontaneous ocular lesions in various laboratory animal species and to facilitate the evaluation of study findings in a preclinical toxicity study. Ophthalmologic...
The purpose of this study was to establish a database of spontaneous ocular lesions in various laboratory animal species and to facilitate the evaluation of study findings in a preclinical toxicity study. Ophthalmologic examination (OE) records for laboratory animals before experiments from 2008 to 2023 were collected from the Provantis system at WuXi AppTec (Suzhou, China), including 23,388 CD-1 mice, 1,838 C57BL/6J mice, 193,076 Sprague-Dawley (SD) rats, 2,295 Wistar rats, 1,875 New Zealand White (NZW) rabbits, 1,794 Dutch belted (DB) rabbits, 32,919 Beagle dogs, 1,153 Bama minipigs, 23,706 cynomolgus monkeys, and 310 rhesus monkeys. These raw data were analyzed using the Fisher exact test. The most apparent features were as follows. SD and Wistar rats showed significantly higher incidences of corneal opacity (72.50% and 77.63%) compared with the other species, as well as persistent hyaloid artery (7.93%) and persistent pupillary membrane (2.75%); C57BL/6J mice had a significantly higher incidence of lens opacity (75.57%) compared with the other species; CD-1mice had more eccentric pupils (6.97%); rabbits were observed with more vitreous opacity and conjunctival hyperemia (12.88% and 1.88%); nontapetal redness was observed in dogs (2.83%); Bama minipigs showed higher incidences in ocular discharge, lens pigmentation, and esotropia (2.78%, 3.14%, and 2.25%); and leopard fundus was mostly found in monkeys (10.32%). The discrepancies between our results and relevant literature may be attributed to variations in genetic background, ingredients of diet, study sample size, and examination records. This study underlines the importance of establishing an in-house spontaneous lesion database.
Evaluating the Physiological and Sedation Parameters of Zenalpha (Medetomidine and Vatinoxan Hydrochloride Injection) in Combination with Ketamine in Rhesus Macaques (Macaca mulatta).
Stasula U, Carroll K, Taguchi T … +4 more , Shelton K, Stockinger D, Lemoy MJ, Timmel G
J Am Assoc Lab Anim Sci · 2026 May · PMID 42086234 · Full text
Alpha-2 adrenergic agonists such as dexmedetomidine are widely used for sedation in rhesus macaques (Macaca mulatta) but are associated with undesired cardiovascular effects. Zenalpha (Dechra, Overland Park, KS), a combi...
Alpha-2 adrenergic agonists such as dexmedetomidine are widely used for sedation in rhesus macaques (Macaca mulatta) but are associated with undesired cardiovascular effects. Zenalpha (Dechra, Overland Park, KS), a combination of medetomidine and the peripheral α2 antagonist vatinoxan, has demonstrated improved physiologic stability in other species but has not been evaluated in nonhuman primates. This study assessed the cardiopulmonary effects and sedation quality of ketamine alone, ketamine combined with dexmedetomidine (500 μg/m2) for 30 or 60 minutes, and ketamine combined with Zenalpha (medetomidine 1 mg/m2 and vatinoxan 20 mg/m2) for 30 or 60 minutes in 10 adult rhesus macaques with 7-day washout intervals between immobilization events. A second study phase evaluated reduced α2 agonist doses, with each animal undergoing 2 additional immobilization events: ketamine + dexmedetomidine (250 μg/m2) and ketamine + Zenalpha (0.5 mg/m2). Physiologic parameters were recorded every 5 minutes, and sedation depth was scored every 10 minutes. Atipamezole (5,000 μg/m2 IM) was administered after the assigned immobilization period for dexmedetomidine and Zenalpha sessions (30 or 60 minutes). Across both phases, ketamine + Zenalpha produced higher heart rates, higher oxygen saturation, and lower mean arterial pressure compared with ketamine + dexmedetomidine while maintaining adequate sedation for up to 60 minutes. Reduced-dose protocols in phase 2 produced sedation comparable to full-dose combinations. These findings suggest that Zenalpha combined with ketamine may offer a more balanced cardiovascular profile than dexmedetomidine-based sedation protocols in rhesus macaques.
Preparation of Pseudopregnant Recipient Females Using Female Mice (Mus musculus) Showing Nonestrous Signs: Investigation of a Unique Approach Based on the Whitten Effect.
Noguchi Y, Watanabe E
J Am Assoc Lab Anim Sci · 2026 Apr · PMID 42036132 · Full text
Availability of pseudopregnant recipient females is an essential component of embryo transfer in mice. However, conventional methods for sorting females based on estrous signs (proestrus or estrus) require maintaining a...
Availability of pseudopregnant recipient females is an essential component of embryo transfer in mice. However, conventional methods for sorting females based on estrous signs (proestrus or estrus) require maintaining a large stock of mice, thereby presenting challenges for animal welfare. Furthermore, these large numbers of female mice are often maintained in group housing due to space constraints; and this can induce the Lee-Boot effect, leading to decreased preparation efficiency. Therefore, this study examined a method for preparing pseudopregnant recipient females using mice showing nonestrous signs through a unique approach based on the Whitten effect. Female ICR mice exhibiting metestrus or diestrus characteristics were deliberately sorted and housed with vasectomized males for 3 consecutive days. The Lee-Boot effect was induced through group housing to increase the proportion of females showing nonestrous signs, followed by Whitten effect induction aimed at achieving successful copulation on day 3. Results demonstrated copulation success rates of 74.4% (CLEA Japan, n = 500) and 77.0% (Japan SLC, n = 200) on day 3, significantly higher than random mating controls during the same period (53.5%, Japan SLC, n = 101; December to May). Subsequent embryo transfers achieved high pregnancy rates of 93.1% and 89.6%, respectively. This approach demonstrated the feasibility of using mice showing nonestrous signs, previously overlooked in conventional methods, for preparing pseudopregnant recipient females. When combined with conventional methods, this approach expands the range of mice available for mating and potentially enables more efficient production of pseudopregnant recipient females while minimizing the total number of female mice required. This advancement aligns with the Replacement, Reduction, and Refinement (3Rs) principles of animal experimentation, particularly the reduction principle, and provides a practical strategy for laboratories seeking to perform embryo transfer procedures with smaller mouse numbers.
Customized Open Patch Allergen Testing in a Rhesus Macaque (Macaca mulatta).
Frankel JS, O'Brien KM, Makaron L
J Am Assoc Lab Anim Sci · 2026 Apr · PMID 42031368 · Publisher ↗
An adult rhesus macaque (Macaca mulatta) presented with chronic, progressive dermatitis and alopecia refractory to dietary modification, environmental enrichment, and medical management. A comprehensive dermatologic work...
An adult rhesus macaque (Macaca mulatta) presented with chronic, progressive dermatitis and alopecia refractory to dietary modification, environmental enrichment, and medical management. A comprehensive dermatologic workup was performed, including the application of a customized open patch allergen testing protocol to evaluate suspected environmental exposures. Patch testing identified a commercial dish soap used in routine sanitation as the likely causative contact allergen. Discontinued use of the product resulted in complete and sustained resolution of clinical signs, with recurrence only following accidental reintroduction of the soap to the facility. To our knowledge, this is the first report describing the use of customized open patch allergen testing to identify a specific contact allergen in a nonhuman primate, highlighting its potential utility as a diagnostic tool in laboratory animal medicine.
Evaluation of Short-Term Stall Size Housing on the Behavior and Welfare of Domestic Horses (Equus caballus).
Outouil M, Daugherity EK, Warnick LD … +1 more , Perry PJ
J Am Assoc Lab Anim Sci · 2026 Apr · PMID 42014105 · Publisher ↗
Single-stall housing is a common system used for horses in various settings, including racing stables, riding schools, teaching and research facilities. Adequate stall space is necessary for horses to lie down and make p...
Single-stall housing is a common system used for horses in various settings, including racing stables, riding schools, teaching and research facilities. Adequate stall space is necessary for horses to lie down and make postural adjustments, both of which are essential for equine rest and welfare. The Guide for the Care and Use of Laboratory Animals recommends a stall size of 144 ft2. However, not all stalls meet this size requirement, and there is limited literature supporting its use in terms of animal welfare. This study used a crossover design to compare behavioral and physiologic variables indicative of welfare of horses housed in the standard recommended 144-ft2 stall compared with a smaller stall (136 ft2) to determine whether the smaller stalls affected horses' welfare and behavior. Eight horses (1,380-1,640 lb) were paired with preferred associates resulting in 4 pairs. One horse from each pair was randomly assigned to be housed in either the standard stall (144 ft2) or the smaller stall (136 ft2) for 4 days (from Monday morning through Friday morning), while the paired horse was housed in the opposite-sized stall. After this initial stall period, all horses were turned out to pasture for 9 days before being housed in the alternate-sized stall for an additional 4 days. Hay consumption, fecal output, and serum cortisol were quantified daily. Movement and duration of recumbency were measured with an accelerometer, and continuous video recordings of all horses were obtained while housed in the stalls (total of ∼96 hours per horse per stall condition). Behavioral variables (resting, locomotion, standing, consummatory, elimination, and stereotypic behavior) were scored every 5 minutes from the recordings and compared between stall conditions. Although several measures changed across days in both stall conditions, stall size did not affect the horses' hay consumption, fecal output, or cortisol concentrations, nor the duration of sternal or lateral recumbency as determined by accelerometer data. However, the duration of walking recorded by the accelerometer different between the 2 stall sizes with horses spending more time walking in the smaller stall (136 ft2). Analysis of video recordings also found no difference in percentage of time spent in sternal or lateral recumbency, rolling, standing, stand resting, walking, eating, or drinking. In conclusion, time budgets, food intake, fecal output, and cortisol concentrations were similar in horses housed in the standard-sized stall (144 ft2) compared with the smaller stall (136 ft2), suggesting that the reduced stall size did not result in observable changes in equine behavior or physiologic welfare indicators compared with the standard-sized stall.
Onset of Analgesia in Rats (Rattus norvegicus) for Three Buprenorphine Formulations.
Alamaw ED, Schwartz KE, Zhang M … +4 more , Franco BD, Jampachaisri K, Huss MK, Pacharinsak C
J Am Assoc Lab Anim Sci · 2026 Apr · PMID 42002281 · Full text
Extended-release buprenorphine has been extensively used in laboratory animal medicine, yet its onset of analgesia in rats remains largely unexplored. This study aimed to investigate the analgesic onset of 3 different ex...
Extended-release buprenorphine has been extensively used in laboratory animal medicine, yet its onset of analgesia in rats remains largely unexplored. This study aimed to investigate the analgesic onset of 3 different extended-release buprenorphine formulations in rats. Our hypothesis was that the onset of all 3 buprenorphine formulations are comparable and are detectable as early as 5 minutes after administration in rats. Sprague-Dawley rats (both male and female, n = 40) were randomly assigned to 4 treatment groups: (1) saline (1 mL/0.1 kg SC, once); (2) Bup-ER (1.2 mg/kg SC, once); (3) Ethiqa-XR (0.65 mg/kg SC, once); and (4) LAT-Bup (Zorbium, 10 mg/kg transdermal, once). Thermal sensitivity (using a hot plate test) was assessed at time points of 5, 15, 30, 45, 60, 120, 180, and 240 minutes following drug administration. Results were as follows: (1) compared with the saline group, Bup-ER's thermal latency significantly increased at 45 (11.05 ± 1.13), 60 (12.5 ± 1.16), 120 (13.7 ± 1.24), 180 (12.48 ± 0.81), and 240 (11.64 ± 0.7) minutes; (2) Ethiqa-XR's thermal latency significantly increased at 180 (12.01 ± 0.6) and 240 (11.76 ± 0.81) minutes; and (3) LAT-Bup's thermal latency significantly increased at 120 (11.27 ± 1.16), 180 (13.97 ± 1.35), and 240 (14.8 ± 1.26) minutes. There were no differences between sexes. LAT-Bup and Bup-ER provided buprenorphine plasma levels exceeding the purported therapeutic threshold of 1 ng/mL by 5 minutes, while Ethiqa-XR exceeded the threshold at 45 minutes. We concluded that these 3 buprenorphine extended-release formulations did not exhibit a time to onset of analgesia within 5 minutes. This study demonstrates that despite all 3 extended-release formulations reaching a purported plasma therapeutic threshold earlier, the clinical onset of analgesia for the hot plate test was shortest for Bup-ER (45 minutes), followed by LAT-Bup (120 minutes) and Ethiqa-XR (180 minutes) in Sprague-Dawley rats.
Port of Choice: Induction Chamber Inlet Position Affects Speed of Isoflurane Induction in Mice.
Alamaw ED, Gaudiel AR, Zhang M … +5 more , Franco BD, Jampachaisri K, Huss MK, Sharp PE, Pacharinsak C
J Am Assoc Lab Anim Sci · 2026 Apr · PMID 42002279 · Publisher ↗
Various factors affect inhalant anesthetic induction speed in mice. We investigated the effects of different inhalant anesthetic inlet port positions on isoflurane induction speed in 3 mouse strains. We considered 3 anes...
Various factors affect inhalant anesthetic induction speed in mice. We investigated the effects of different inhalant anesthetic inlet port positions on isoflurane induction speed in 3 mouse strains. We considered 3 anesthetic inlet port positions: conventional (port located in a traditional location approximately halfway between the induction box lid and base), top (port incorporated into the induction box lid), and bottom (port located adjacent to the base, but on the side wall). We hypothesized that positioning the anesthetic inlet port at the bottom of the induction chamber would result in a shorter induction time compared with the conventional inlet placement across all 3 mouse strains. This crossover study design involved randomly assigning mice undergoing isoflurane anesthetic induction with one of the custom-designed inlet positions: conventional, top, or bottom inlet port. C57BL/6, NSG, and Alb-Cre Foxm1b-/- male and female mice were used (n = 60, 20 mice per strain). The anesthetic induction speed was evaluated as the (1) time to immobility and (2) time to loss of righting reflex (LORR) - the time to loss of righting reflex by slightly tilting induction chamber. In C57BL/6 mice, the time to immobility was shorter using the bottom inlet port than with the conventional inlet. In NSG mice, the time to immobility was longer using the top inlet port than with the conventional inlet. In Alb-Cre Foxm1b-/- mice, inlet port position did not affect the time to immobility. For the time to LORR, in C57BL/6 mice, the bottom inlet resulted in shorter times to LORR compared with the top inlet, while no difference was detected between the bottom and conventional inlets. For Alb-Cre Foxm1b-/- mice, the bottom inlet produced shorter LORR times compared with both the top and conventional inlets. In NSG mice, inlet position did not significantly affect LORR times. This study suggests that a bottom gas anesthetic inlet port position provides the shortest (fastest) anesthetic induction for C57BL/6 and Alb-Cre Foxm1b-/- mice, but not for NSG mice.
Evaluating Subtypes of Endometriosis in Rhesus Macaques (Macaca mulatta) Using Clinical Findings and Immunohistochemistry.
Johnson AA, Wilkes AC, Easley KA … +2 more , Machiah DK, Roy MA
J Am Assoc Lab Anim Sci · 2026 Apr · PMID 42002274 · Full text
Endometriosis is defined as endometrial tissue outside of the uterus. It is a debilitating, complex, and underdiagnosed condition, impacting approximately 10%-15% of reproductive-aged women worldwide. Endometriosis is as...
Endometriosis is defined as endometrial tissue outside of the uterus. It is a debilitating, complex, and underdiagnosed condition, impacting approximately 10%-15% of reproductive-aged women worldwide. Endometriosis is associated with chronic pain, infertility, diminished well-being from invasive and delayed diagnostics, and limited treatment options. It is reported to cause approximately 23,000 hospitalizations and cost approximately $9 billion annually due to reduced quality of life and productivity. Endometriosis also occurs spontaneously in rhesus macaques (Macaca mulatta), and similar negative impacts are seen in research colonies. Despite extensive research in both species, much remains unknown about its etiopathogenesis, especially regarding uncommon presentations. This retrospective observational cohort study evaluated clinical findings from 68 rhesus macaques diagnosed with endometriosis at the Emory National Primate Research Center and characteristics associated with their endometriosis lesions. Animals were categorized into 4 endometriosis subtypes: pelvic, abdominal, extra-abdominal, and invasive. Prevalence and descriptive statistics were calculated for reproductive history, physical exam findings, and other observations related to an endometriosis diagnosis. In addition, immunohistochemical analysis was performed on lesions from a subset of 27 macaques and 6 controls to evaluate variation in mean staining intensity and distribution (±SEM) for estrogen receptor α (ERα), progesterone receptor (PR), and CD10 antibodies. Clinical data corroborated established literature by demonstrating common findings associated with endometriosis. It provided novel information by examining the relationship and patterns of these findings in uncommon presentations of endometriosis. Analysis of mean staining intensities (±SEM) revealed significant differential expression of ERα and PR in abdominal endometriosis compared with extra-abdominal and invasive subtypes, as well as autologous eutopic uterine tissue. This study provides important data that may begin to unravel some of the underlying mechanisms by which endometriosis behaves in varied ways.
The Role of Antibody Testing Using Commercially Available Reagents in Tuberculosis Surveillance Algorithms Being Developed for Nonhuman Primate Breeding Colonies.
Yee JL, Haertel AJ, Allers C … +7 more , Carpenter A, Palmer H, Barnes M, Falkenstein KP, Van Rompay KKA, Timmel G, Roberts JA
J Am Assoc Lab Anim Sci · 2026 Apr · PMID 42002273 · Full text
The detection and elimination of Mycobacterium tuberculosis complex-infected nonhuman primates (NHPs) is vitally important to ensure the biosecurity and health of the individual animals as well as the NHP colonies and hu...
The detection and elimination of Mycobacterium tuberculosis complex-infected nonhuman primates (NHPs) is vitally important to ensure the biosecurity and health of the individual animals as well as the NHP colonies and humans who have contact with them. In the century since the tuberculin skin test was developed and used for detection, additional tests targeting the organisms or the host response to them have been proposed as alternative or adjunct pieces to build a testing algorithm. None has gained widespread acceptance for use in NHPs. A major obstacle has been the lack of rigorous studies to validate the use of these tests, especially comparisons against isolation via culture, the long accepted but less than perfect and often technically challenging gold standard. The changing biology of infection over time and the lack of availability of statistically powerful numbers of well-characterized samples from known naturally infected subjects have been additional obstacles. Recent studies have examined the use of newer assays such as IFNγ release assays for cell-mediated immune responses and PCR tests for direct agent detection. In this study we explored the use of antibody testing using commercially available reagents: 39 nonnegative skin tests and 16 nonnegative antibody tests were found in 593 animals from 3 large, stable, long-term breeding colonies. Using multiple tests, infection was not confirmed in any of the animals. Thus, antibody testing may be another useful tool for TB surveillance in NHPs.
Acute Comparative Analysis of Anesthetic Methods in Neonatal Mice (Mus musculus) Using Ultrasonic Vocalizations and Biochemical Markers.
Diaz-Anderson S, Delva-Wiley J, Lee S … +2 more , Lamont K, Williams MD
J Am Assoc Lab Anim Sci · 2026 Apr · PMID 41962932 · Full text
Hypothermia has been used as an anesthetic technique in neonatal rodents since 1934. While the long-term impacts of neonatal anesthetic exposure in adult mice are still under investigation, its acute effect during the ne...
Hypothermia has been used as an anesthetic technique in neonatal rodents since 1934. While the long-term impacts of neonatal anesthetic exposure in adult mice are still under investigation, its acute effect during the neonatal period is poorly characterized. Although hypothermia can achieve sufficient anesthetic depth to eliminate pain sensation, its effect during induction and recovery remains unclear. Mice emit ultrasonic vocalizations (USVs) within a range of 30-120 kHz for normal behavior and communication, with lower frequencies often associated with pain and distress. Using USV analysis and other physiologic measures, we assessed the well-being of neonatal mice subjected to different anesthetic exposures at different ages (postnatal day [PND] 2, 5, 8, 11, and 14). C57BL/6 neonatal mice (n = 483) were randomly assigned to 1 of 7 groups: no handling or anesthesia, handling only, hypothermia (PND 2, 5, and 8 only), isoflurane vaporizer, sevoflurane vaporizer, isoflurane drop, or sevoflurane drop methods. USVs were recorded at 4 time points: before the anesthetic exposure (T0), immediately during recovery (DR), 5 minutes after recovery (PR), and 120 minutes after recovery (T120) (n ≥ 12 pups per group). Induction and recovery were timed. At T120, terminal blood was collected to measure stress-related biochemical markers (blood glucose, corticosterone, norepinephrine). Our results show that neonatal mice receiving hypothermia anesthesia had significantly lower frequency of USVs during and after recovery, longer duration of USV calls, and longer recovery time compared with other anesthetic groups. Our findings suggest that hypothermia anesthesia induces acute distress in neonatal mice ≤PND 8 compared with inhalational anesthetics. In accordance with the principles of the 3Rs to minimize pain and distress, using inhalant anesthesia (isoflurane or sevoflurane) is preferable to hypothermia for neonatal anesthesia in mouse pups at ≤PND 8.
Recurrent Cystolithiasis with Urethral Obstruction in a Rhesus Macaque (Macaca mulatta) after a Bilateral S1 Ventral Root Avulsion Injury.
Carroll KE, Qiu Y, Chu P … +3 more , Christe KL, Nieto JH, Havton LA
J Am Assoc Lab Anim Sci · 2026 Apr · PMID 41934962 · Full text
A series of adult male (n = 6) and female (n = 4) rhesus macaques (Macaca mulatta) underwent a bilateral S1 ventral root avulsion injury for longitudinal lower urinary tract studies in a motor-sparing experimental model...
A series of adult male (n = 6) and female (n = 4) rhesus macaques (Macaca mulatta) underwent a bilateral S1 ventral root avulsion injury for longitudinal lower urinary tract studies in a motor-sparing experimental model of conus medullaris syndrome. The surgeries were well tolerated, and all animals recovered well postoperatively. However, one male animal presented clinically with acute lethargy, poor appetite, and unwillingness to move at 51 days after the bilateral S1 ventral root avulsion injury. Physical examination under sedation detected an enlarged bladder, which was emptied via transurethral bladder catheterization. When the animal re-presented for similar symptoms over the following 2 days, radiographic and ultrasound studies revealed cystolithiasis with urethral obstruction. Repeat transurethral bladder catheterizations reestablished functional patency of the urethra, independent voiding, and full clinical recovery. Two weeks later, the animal presented again with acute lethargy, poor appetite, unwillingness to move, and an enlarged bladder. Cystolithiasis and the recurrence of urethral obstruction were diagnosed by radiographic and sonographic studies. Subsequent transurethral bladder catheterization was unable to dislodge the obstruction, and the animal was euthanized. Necropsy identified 3 bladder stones. Histochemistry of the bladder and urethral walls showed some acute inflammation but absence of chronic changes. Chemical analysis of bladder stone composition showed calcium phosphate (90%) and calcium carbonate (10%). Our case highlights the value of an expedited physical examination and noninvasive imaging to diagnose cystolithiasis complicated by an acute urethral obstruction, a medical emergency, in a rhesus macaque presenting with nonlocalizing symptoms. Although spinal cord injury is an established risk factor for urolithiasis in humans, our case provides the first (to our knowledge) association of a spinal cord injury syndrome with cystolithiasis in a nonhuman primate.
Letter to the Editor: The Value of a Paired Design Approach as a Strategy for Reduction of Animal Use.
Roussoulieres I, Barbosa C, Lilenbaum W
J Am Assoc Lab Anim Sci · 2026 Mar · PMID 41881400 · Full text
Abstract loading — click title to view on PubMed.
Cage-Side Blood Collections from the Ear Can Be Used for Hematological Evaluations in Japanese Macaques (Macaca fuscata).
Kim GA, Sabnis SS, Sheridan TA … +7 more , Chester G, Argomaniz MA, Cheng WT, Roberson SH, Saney CL, McCrackin MA, Joyner CJ
J Am Assoc Lab Anim Sci · 2026 Mar · PMID 41881388 · Full text
Japanese macaques (Macaca fuscata) are used in biomedical research where frequent, small-volume blood sampling for monitoring the animal's health may be required. Femoral blood collected under anesthesia is the standard...
Japanese macaques (Macaca fuscata) are used in biomedical research where frequent, small-volume blood sampling for monitoring the animal's health may be required. Femoral blood collected under anesthesia is the standard for obtaining CBC analyses from nonhuman primates to assess their health. However, anesthetizing animals to obtain these collections may not be ideal due to adverse impacts of frequent anesthesia. Cage-side blood sampling from the pinna of the ear is a convenient and less invasive method for blood collection without anesthesia. However, it is unknown whether hematologic parameters from blood collected from the pinna are representative of femoral blood collections. The objective of this study was to determine whether hematologic parameters obtained from blood collected from the pinna of the ear can be used as a surrogate for hematologic parameters from blood collected from the femoral vein in Japanese macaques. Ten male Japanese macaques were trained to present their pinnae for blood collections without anesthesia, after which the macaques were anesthetized for pinna and femoral blood sampling for comparison. Anesthesia, rather than blood sampling site, was responsible for statistically significant differences in leukocyte parameters between pinna and femoral blood samples. In contrast, differences in erythrocyte and platelet parameters between pinna and femoral blood were driven by the collection site, with anesthesia contributing to a lesser degree. While statistical differences were identified, the clinical relevance of these differences was minimal. Taken together, this study indicates that cage-side pinna blood samples collected from conscious Japanese macaques are different than femoral blood samples collected under anesthesia but are suitable for frequent hematologic monitoring.
Beyond Comfort: A Review of the Critical Role of Bedding Selection in Rodent Welfare, Microenvironment, and Research Reproducibility.
O'Connell KA, Celdran-Bonafonte D
J Am Assoc Lab Anim Sci · 2026 Mar · PMID 41844212 · Full text
This review addresses the critical but often underappreciated influence of bedding selection on rodent welfare, cage microenvironment, occupational health, and research outcomes in biomedical studies. Although contact be...
This review addresses the critical but often underappreciated influence of bedding selection on rodent welfare, cage microenvironment, occupational health, and research outcomes in biomedical studies. Although contact bedding is widely preferred by mice and rats and is the current industry standard, there is considerable variation in bedding type, volume, sterility, and manufacturer practices, with no established universal protocols. We synthesize over 150 publications, evaluating corncob, wood, and cellulose-based beddings with respect to their physical attributes, absorbency, ammonia management, dust and contaminant control, and support of species-typical behaviors. The review highlights methodological challenges and inconsistent results across studies, with absorbency and ammonia accumulation particularly affected by bedding mass, volume, and microbial contamination, rather than material type alone. Occupational health risks, including ergonomic strain and allergen exposure, are impacted by bedding handling frequency and composition. Animal health is generally not strongly influenced by bedding type, although pine shavings and certain corncob products present toxicity and reproductive risks in some studies. Bedding also has documented impacts on hepatic enzyme induction, neurobehavioral development, pain sensitivity assays, and gut microbiome composition, posing substantial risks for experimental confounding and compromised reproducibility. Based on the evidence, cellulose bedding is recommended for minimizing negative outcomes, but the complexity and variability inherent in bedding selection necessitate careful documentation and transparent reporting. We advocate for standardized detail in publications to ensure comparability and rigor across rodent-based research.
Oxygen Supplemented via Face Mask Counteracts Hypoxemia in Capuchin Monkeys (Sapajus spp.) under Butorphanol-Ketamine-Midazolam Restraint.
Ferreira ME, Justo AA, Lima AFKT … +3 more , Moncayo JR, Laurito BR, Cortopassi SRG
J Am Assoc Lab Anim Sci · 2026 Mar · PMID 41844202 · Full text
This prospective, randomized, complete crossover study evaluated the effects of supplemental oxygen on arterial oxygenation and recovery quality in adult capuchin monkeys (Sapajus spp.; n = 8; 6 males and 2 females) chem...
This prospective, randomized, complete crossover study evaluated the effects of supplemental oxygen on arterial oxygenation and recovery quality in adult capuchin monkeys (Sapajus spp.; n = 8; 6 males and 2 females) chemically restrained with intramuscular butorphanol (0.5 mg/kg), ketamine (15 mg/kg), and midazolam (1 mg/kg). Each monkey underwent 2 anesthetic events, separated by a 2-week interval: one breathing room air (GAIR) and one receiving oxygen via face mask at 3 L/min (GOXY), both conducted during dorsal recumbency. Heart rate (HR), respiratory rate (RR), peripheral oxygen saturation (SpO2), and rectal temperature were registered every 10 minutes for 45 minutes. Arterial blood gases were analyzed at 10 and 30 minutes postrestraint, with oxygen supplementation in GOXY initiated after the 10-minute time point and maintained for 35 minutes. Recovery was continuously video-recorded for later assessment of time to standing and recovery quality by one blinded and one nonblinded observer. At 10 minutes, 14 of 16 monkeys exhibited hypoxemia (partial pressure of arterial oxygen [PaO2] range: 48-81 mm Hg). By 30 minutes, PaO2 and arterial oxygen saturation (SaO2) increased significantly in GOXY, reaching 298-458 mm Hg and 100%, respectively, whereas GAIR animals remained hypoxemic (47-70 mm Hg and ≤92%, respectively). Pulse oximetry-derived SpO2 consistently overestimated saturation at low SaO2 values. The partial pressure of carbon dioxide (PaCO2) rose significantly in GOXY, with hypercapnia (PaCO2 range: 33-57 mm Hg) documented in 6/8 individuals at 30 minutes. In contrast, no cases of hypercapnia were observed in GAIR (PaCO2 range: 22-45 mm Hg) at the same time point. No significant between-group differences were detected in SpO2, HR, RR, or temperature over time. Time to standing and recovery quality were similar between groups. Supplemental oxygen via face mask effectively corrected hypoxemia in Sapajus spp. chemically restrained with butorphanol, ketamine, and midazolam.
Ethical Architecture and Scientific Partnership: The Enduring Role of the Laboratory Animal Veterinarian.
Suckow MA, Myers DD
J Am Assoc Lab Anim Sci · 2026 Mar · PMID 41833308 · Full text
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