Whales, Earth’s largest mammals and live in water, form long bones without marrow cavities. Body size and mechanical stress impact the bone formation and homeostasis, yet the specific developmental processes remain unclear. Here, we demonstrate the histological changes in whale long bones from fetal to mature stages using the radius of Antarctic minke whales in comparison with domestic cats and cattle. Through intramembranous ossification and remodeling, long bones enlarge their diameters and marrow cavities, respectively. It has been demonstrated that relatively small animals, such as cats, develop the radially arranged “primary osteonal bone,” whereas larger animals, including cattle, form “laminar bone” initiated by the formation of circumferentially arranged hypercalcified lines during intramembranous ossification. Here, we demonstrated that whales form laminar bones, transitioning from circumferential in the fetus to radial during postnatal growth, and thereafter cortical bones become compact. After maturation, bone remodeling primarily occurs in the lateral and medial regions of long bones, while the bone layers in the cranial-caudal region never undergo complete resorption. As a result, these layers remain as a wire-netting structure composed of thin bone layers, without forming an open medullary cavity. These data suggest that whales enlarge their long bones through laminar bone formation and form long bones without a marrow cavity by regulating bone resorption areas during the developmental process and in maintaining homeostasis.

Although the disk diffusion method is a useful and widely utilized antimicrobial susceptibility testing method in clinical veterinary practice, the available clinical breakpoints (CBPs) for the combination of bacterial species and antimicrobials are still limited. This study aimed to establish tentative cut-off values by analyzing the relationship between minimum inhibitory concentration and the inhibition zone diameter of the disk diffusion method for Pasteurella multocida and Mannheimia haemolytica, collected by the Japanese Veterinary Antimicrobial Resistance Monitoring system (JVARM), for the antimicrobial agents approved in Japan for the treatment of respiratory diseases in cattle and swine. Among the antimicrobial agents without CBPs for the disk diffusion method in the Clinical and Laboratory Standards Institute (CLSI), we were able to determine the tentative cut-off values of ampicillin (ABPC, S ≥25 mm, R ≤24 mm in swine), dihydrostreptomycin (DSM, S ≥8 mm in cattle, S ≥12 mm in swine), kanamycin (KM, S ≥16 mm in cattle, S ≥17 mm in swine), tetracycline (TC, S ≥21 mm, R ≤20 mm in cattle) and tiamulin (TML, S ≥13 mm in swine) for P. multocida, and CEZ (S ≥23 mm), DSM (S ≥10 mm), KM (S ≥18 mm) and TC (S ≥23 mm, R ≤20 mm) for M. haemolytica. These results should encourage the practical use of antimicrobial susceptibility testing in the clinical field and contribute to furthering prudent use of antimicrobial agents.

Glanders is a World Organization for Animal Health (WOAH)-notifiable equine disease caused by the infection of Burkholderia mallei, and is endemic in Mongolia, South Asia, Africa, and South America. While the complement fixation test (CFT) has been widely used for serodiagnosis of glanders and is considered a standard serological test, it has several limitations. These limitations include poor specificity, labor intensive techniques, variability in antigen and protocol. Consequently, indirect enzyme-linked immunosorbent assays (iELISAs) based on recombinant proteins have been developed as alternative serodiagnostic assays to address some of the challenges associated with the CFT. The accuracy of iELISA relies on the B. mallei proteins used as an antigen. Hence, to determine the best diagnostic candidate in iELISA, in terms of sensitivity and specificity, a comparison of 17 immunogenic B. mallei proteins and detergent-based whole cell lysate (WCL) was performed. According to the sensitivity and specificity on the sera from glanderous and non-glanderous Mongolian native horses, iELISA using Hcp1, GroEL, and detergent-based WCL represented the highest diagnostic accuracy. These three candidates did not have cross-reactivity to horse sera with several other equine diseases. WCL, Hcp1, and GroEL showed considerable potential as antigens for iELISA in the serodiagnosis of glanders in Mongolia. Detergent-based WCL extraction offers a consistent approach for the preparation of reliable B. mallei antigen. WCL-iELISA should be further validated in a large-scale study to meet WOAH demands.

This study describes the echocardiographic reference intervals in a large sample of Golden retrievers from the database of the Italian Veterinary Observatory for Cardiac Diseases. The echocardiographic variables and the cardiac functionality indexes obtained from 2012 to 2022 in 214 (122 females, 92 males) healthy adult Golden retrievers were compared with the previously published data for this breed and with data from the general canine population and other breeds. The diastolic left ventricular internal diameter and the left ventricle’s systolic and diastolic allometric indices were higher than those reported for the general canine population (P<0.05). The same was true for the left ventricular end-diastolic and end-systolic volumes measured by Simpson’s method of discs (P<0.01). Fractional shortening of the left ventricle was lower (P=0.002) and aortic flow velocity was higher (P<0.001) than the value previously reported for Golden retrievers. The reference intervals obtained in this study are useful for clinical echocardiography and for echocardiographic screening programs in Golden retrievers.

Keratoconjunctivitis sicca (KCS) is a common ocular disease in dogs characterized by inflammation of the cornea and conjunctiva. This study investigates the effectiveness of gelatin-epigallocatechin gallate nanoparticles with hyaluronic acid coating (GEH NPs) and various artificial tears in treating KCS led keratopathy in a rat model. Eighteen female Sprague-Dawley rats, aged 6 to 8 weeks were randomly assigned to 6 groups of 3. All rats except the Sham group underwent unilateral exorbital and infraorbital lacrimal gland excisions to induce KCS. The treatment groups included a KCS group without treatment, a GEH group treated with GEH NPs, and 3 groups receiving different artificial tears. Clinical examinations, including slit-lamp biomicroscopy, optical coherence tomography (OCT), and ocular surface analyser-VET (OSA-VET) were conducted preoperatively at 1 and 2 weeks postoperatively. For treating KCS associated keratopathy, the GEH NPs showed superior outcomes and consistently ranked among the strongest treatment options in most aspects evaluated, including reduced corneal irregularity, improved tear film stability, and lower fluorescein scores, indicating better corneal integrity. Additionally, the GEH group displayed the least inflammatory cell infiltration and maintained a healthier epithelial structure, further underscoring its protective effects. GEH was administered twice daily while other treatment groups were administrated 3 times daily, highlighting its efficacy even with a lower dosing frequency. The artificial tears demonstrated variable benefits on KCS led keratopathy across different evaluations. GEH NPs exhibited excellent protective effects and therapeutic potential on dry eye associated keratopathy based on this study.

Spontaneous cardiac disease in nonhuman primates offers a useful model of human cardiac disease. However, diagnosing heart disease generally requires specialized techniques such as ultrasonography. This study focused on cardiac hormones that can be used to detect cardiac disease from blood tests. We measured concentrations of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in healthy young Japanese macaques (Macaca fuscata) housed individually indoors, with no abnormalities in thoracic X-rays, electrocardiograms, echocardiograms, or complete blood counts and serum biochemistry tests, to establish reference values. The monkeys used in this study comprised 29 males (28–47 months old) and 29 females (22–65 months old). ANP levels were determined by immunoradiometric assay. BNP levels were determined by chemiluminescent enzyme immunoassay. Mean ANP level was 25.7 ± 9.6 pg/mL for all 58 Japanese macaques, 26.7 ± 9.6 pg/mL for the 29 males, and 24.7 ± 9.5 pg/mL for the 29 females. No significant difference was identified between sexes. No correlation was seen between ANP and age but excluded monkeys showed result of outside these range. BNP was also measured, with 22 of the 58 monkeys showing levels below the lower limit of detection (<4.0 pg/mL). Taking levels in these 22 animals as 4.0 pg/mL, mean BNP level was 5.1 ± 1.6 pg/mL and BNP elevated in two excluded monkeys. These results establish mean values for cardiac hormones in young Japanese macaques. These standards may provide useful indicators for the early detection of cardiac disease in animal models.

Although the combination of medetomidine, midazolam, and butorphanol (Me/Mi/Bu) is a commonly used surgical anesthetic for small laboratory animals, the effects of Me/Mi/Bu on the central nervous system remain to be confirmed, and some researchers have questioned the use of Me/Mi/Bu as a surgical anesthetic. Herein we employed cFos-immunohistochemistry to assess the stress-relieving effects of Me/Mi/Bu and isoflurane on the murine brain in response to restraint stress. The results demonstrated that the number of cFos-immunopositive cells in the paraventricular nucleus was significantly lower in the mice anesthetized with Me/Mi/Bu or isoflurane compared to those that were not anesthetized. These findings suggest that Me/Mi/Bu exerts an effect on the brain that is similar to that of isoflurane in alleviating the response to surgical procedures.

A rapidly growing mass was observed in the left third mammary gland of a 5-and-a-half-year-old intact female northern tree shrew (Tupaia belangeri). Histopathologically, the mass was composed of numerous irregularly dilated mammary ducts with a pericanalicular or intracanalicular pattern. These mammary ducts showed a leaf-like structure due to the proliferations of surrounding spindle-shaped neoplastic cells with moderate to severe nuclear atypia. We diagnosed this case as a phyllodes tumor in a mammary gland of a northern tree shrew (Tupaia belangeri), which closely resembled those occurring in the human breast histopathologically. To the best of our knowledge, this is the first report of a phyllodes tumor in the mammary gland of a northern tree shrew (Tupaia belangeri).

Oxypeucedanin (OPD) is a compound naturally present in plants such as Peucedanum praeruptorum, a kind of medicinal herb which displays anti-inflammatory activities. However, its protective role on chemotherapy-induced inflammatory injuries has not been well studied. In the present study, we found that OPD could alleviate cisplatin (CDDP)-induced intestinal inflammatory injury in mice, which was accompanied by the decrease of immune cell infiltration and reverse of mitochondrial dysfunction in intestinal tissue. Then we noticed that OPD could inhibit cisplatin-induced intestinal cell pyroptosis, which was indicated by the reduction of LDH release and PI positive signal in the cells and tissues. The reason is that OPD could suppress caspase-3/gasdermin E (GSDME) signaling, which is a critical mediator of chemotherapy-induced tissue injury. We also detected the upstream factors of caspase-3/GSDME signaling and have found that cisplatin-induced Reactive oxygen species (ROS) production and DNA damages could also be inhibited by OPD. Importantly, OPD administration did not reverse cisplatin-suppressed tumor burden in animals. Our present study provides a potential application of OPD to reduce cisplatin-induced side effects, without interfering the anti-tumor capacity, indicating a way to extend the duration of cisplatin administration.

The diagnosis of canine mast cell tumor (MCT) via cytology carries the risk of triggering life-threatening anaphylactic reactions due to massive histamine release. Since mast cells release various lipid mediators, which are excreted in urine, we aimed to explore urinary lipid metabolites as potential non-invasive diagnostic markers for MCT. Liquid chromatography-mass spectrometry-based analysis detected 32 types of lipid metabolites in the urine of MCT dogs. Among these, urinary levels of 15-deoxy-Δ-12,14-PGJ₂, lyso-PAF, 9,10-DiHOME, and 12,13-DiHOME were significantly elevated in MCT dogs compared to healthy dogs. These urinary lipid metabolites can serve as novel non-invasive biomarkers for canine MCT.

Our previous reports showed that exposure to the neonicotinoid pesticide clothianidin (CLO) at a no-observed-adverse-effect-level (NOAEL) dose during fetal development and lactation in mice led to higher rates of maternal neglect and infanticide. Although the demonstrated association between decreased oxytocin secretion and decreased maternal parenting behavior implies a link to declining oxytocin levels, no evidence has yet emerged in CLO to clearly establish such an association. This study investigated the effects of CLO on maternal behavior and oxytocin in C57BL/6N mice exposed during pregnancy and lactation (F0 mothers) as well as in their adult female offspring (F1 mothers). The effects were assessed using nest building assays during pregnancy and pup retrieval assessment after delivery. The results showed a decrease in oxytocin secretion and a marked decrease in pup retrieval behavior among the F0 mothers in the CLO exposure group compared to those in the control group. Their offspring, the F1 mothers, showed significantly lower nest-building scores during pregnancy. In conclusion, this study is the first to examine the potential mechanisms by which CLO exposure in mothers at the NOAEL dose during pregnancy and lactation results in reduced plasma oxytocin levels, subsequently leading to a decline in maternal behaviors such as pup retrieval. Furthermore, these effects may impair maternal behaviors in the next generation, when the offspring mice become mothers.

Fipronil (FPN) inhibits gamma-aminobutyric acid type A receptors and exhibits strong insecticidal effects. Although FPN’s adverse effects on mammals have been reported recently, few studies have examined subchronic exposure to low doses. We orally administered FPN (0.43 mg/kg) to 4-week-old male mice for 6 wk and assessed their behavior and blood characteristics. Compared with the control group, the FPN-treated group presented reduced weight gain but upward trends in locomotor activity and blood histamine levels. Fipronil sulfone (FPNS) was detected in all individuals, whereas FPN was not detected in any individual. The present study shows for the first time that subchronic exposure to low-dose FPN in mice led to FPNS conversion in the body, affecting weight gain and behavior.

This study aimed to investigate the effects of cell differentiation status and neurotropic viral infectivity on the susceptibility of undifferentiated and differentiated SH-SY5Y cells to herpes simplex virus type 1 (HSV-1) and Japanese encephalitis virus (JEV) infections. Notably, undifferentiated SH-SY5Y cells were susceptible to both HSV-1 and JEV infections. However, differentiated cells exhibiting a phenotypically mature neuron-like morphology and markedly increased neuronal marker levels showed low susceptibility to JEV infection. Overall, these findings suggest that SH-SY5Y cells become more resistant to JEV infection as they mature. This cell culture model is useful to elucidate the molecular mechanisms regulating the maturation state-specific resistance of neurons to JEV.

A 3-year-old captive corn snake (Pantherophis guttatus) was taken our veterinary clinic with a complaint of intermittent body swelling. Radiography revealed soft-tissue swelling, and ultrasonography confirmed intussusception of the digestive tract. Celiotomy revealed esophagogastric intussusception, which was subsequently corrected. Histopathological examination of gastric mucosal biopsy and polymerase chain reaction (PCR) from feces were revealed protozoan parasitism within the lesion and detected specific genes of Cryptosporidium spp. Oral administration of paromomycin at 100 mg/kg once daily for 10 days, subsequently twice weekly for 90 days under strict hygiene management were conducted as postoperative treatment. The snake was in good clinical health. PCR and ultrasonography for Cryptosporidium spp. 752 days after surgery showed no evidence of cryptosporidiosis.