Journal of Veterinary Medical Science最新文献

C-telopeptide (CTX) fragments of type I collagen are widely used as markers of bone resorption in mammals. This study evaluated the performance of two enzyme-linked immunosorbent assays (ELISAs) using antibodies against different CTX epitopes-CTP-18 and CTP-8-in ovariectomized (OVX) mice, and examined the cross-species applicability of the CTP-18 ELISA in Pacific bluefin tuna (Thunnus orientalis). In OVX mice, both serum and urinary CTP-18 levels significantly increased compared to sham-operated controls (P<0.05), and were moderately correlated with deoxypyridinoline (DPD) levels and inversely with bone mineral density. In contrast, CTP-8 was less responsive. The CTP-18 antibody cross-reacted with mouse, rat, human, and tuna sera, and showed good dilution linearity in tuna samples. Tuna serum CTP-18 levels were positively correlated with DPD (r=0.82, P<0.05). These findings suggest that the CTP-18-based ELISA is a reliable tool for monitoring bone resorption not only in rodents but also in fish, providing a new approach for assessing skeletal turnover in aquaculture species.

Canine epitheliotropic cutaneous T-cell lymphoma (ECTCL) is a malignant neoplasm exhibiting various skin lesions. Metastasis to the lymph nodes and distant organs contributes to the poor prognosis of ECTCL; however, the underlying molecular mechanisms remain unclear. In the present study, the roles of chemokine receptors, such as CC chemokine receptor (CCR) 4 and CCR7, in the migration of tumor cells were examined using a canine cutaneous lymphoma model. Three mouse groups were prepared and xenografted with wild-type (WT), CCR4 knockout (KO), or CCR7KO canine ECTCL (EO-1) cells. The proportion of EO-1 cells in tissues and blood was significantly lower in the CCR4KO and CCR7KO groups than in the WT group. Only the iliac lymph node, a sentinel lymph node for the xenograft site, was enlarged with the infiltration of EO-1 cells in all groups. The size of the iliac lymph node was smaller in the KO groups than in the WT group. All mice developed a subcutaneous nodule at the xenograft site, which was smaller in the KO groups. In the cell proliferation assay, chemokine ligands stimulated an increase in EO-1 cells in the WT group, but not in the KO groups. These results suggest that CCR4 or CCR7 plays a vital role in the initial migration to sentinel lymph nodes and proliferation in a canine cutaneous lymphoma model.

Isoleucyl-tRNA synthetase 1 (IARS1) is essential for protein synthesis. Although IARS1 mutations cause growth and metabolic disorders in humans, its role in embryonic development remains unclear. We generated Iars1 knockout (KO) mice and observed complete absence of homozygous KOs among 44 pups, indicating embryonic lethality. A χ² test confirmed significant deviation from Mendelian ratios. At E12.5, multiple resorbed implantation sites were observed, and histology at E9.5 showed embryos lacking recognizable structures. Evidence of implantation (decidual swellings with residual trophoblast and maternal vasculature) indicates post-implantation survival but failure to progress beyond early organogenesis. These results demonstrate that IARS1 is indispensable for early mouse development and provide a useful model to study the link between IARS1 deficiency and disrupted organogenesis.

A 6-year and 11-months-old male striped skunk, Mephitis mephitis, showed inappetence and died. Necropsy revealed multiple hepatic masses, an enlarged spleen, wedge-shaped lesions in the kidneys, and a cervical cyst with white nodules. Histopathologically, the hepatic masses were diagnosed as biliary cystadenomas accompanied by chronic inflammation, the cervical cyst was a thymoma, and the splenic and renal lesions were diagnosed as infarctions. Amorphous eosinophilic material was observed in the liver, spleen, and kidney. These proteinaceous deposits were positive for Congo red staining with yellowish to green birefringence under polarized light. These deposits were immunohistochemically positive for amyloid A (AA). This report describes the pathological features of AA amyloidosis, biliary cystadenoma and cervical thymoma in a striped skunk.

A 5-month-old imported boar showed posterior paralysis upon arrival in Japan. Both limbs had coldness, algesia, and thigmesthesia. A thrombus was detected from the abdominal aorta to the left external iliac artery. Irregular vegetation was observed on the left atrioventricular valve. The skeletal muscles in the hind limb appeared like boiled meat. The histological diagnoses were endocarditis, glomerulonephritis, and meningoencephalitis with Gram-negative bacilli as well as diffuse intravascular coagulation and diffuse alveolar damage. The bacilli were identified as Actinobacillus suis via immunohistochemistry and 16S rRNA gene sequencing. This is the first case report of acute posterior paralysis due to iliac thromboembolism in swine with A. suis infection. Iliac thromboembolism should be considered if posterior paralysis is observed in swine.

Gastrointestinal (GI) tumors are common neoplastic diseases in dogs. However, epidemiological data on canine GI tumors in Japan are limited. The present study aimed to investigate the prevalence of GI tumors in Japan and assess the association of canine breed, age, sex, and anatomical location with the development of common tumor types. A total of 1,310 canine GI tumors that were histopathologically examined between 2012 and 2024 were retrospectively analyzed. The statistical methods included a contingency table analysis, multivariable logistic regression analyses, and Mann-Whitney U tests. The most frequent GI tumor was lymphoma (58.9%), followed by adenocarcinoma (16.2%) and adenoma (15.0%). Statistical examination revealed that Shiba dogs were predisposed to T-cell lymphoma, Miniature Dachshunds to colorectal B-cell lymphoma and colorectal adenoma, Jack Russell Terriers to adenoma, acinar adenocarcinoma, papillary adenocarcinoma and tubulopapillary carcinoma, French Bulldogs to gastric signet-ring cell carcinoma and plasmacytoma, and Shih Tzus to tubulopapillary adenocarcinoma. These breed predispositions to specific tumors may be unique to the Japanese canine population. To the best of our knowledge, this is the first large-scale epidemiological investigation of canine GI tumors in Japan. The epidemiological information from the present study will serve as a useful reference for clinical veterinarians to establish the differential diagnoses of canine GI tumors.

Mucosa-associated lymphoid tissue, which plays a crucial role in both immunological protection and inflammation at mucosal sites, shows interspecies variation in its distribution. In the ocular region, lacrimal duct-associated lymphoid tissue (LDALT) has rarely been investigated in animals other than humans or rodents. Although conjunctiva-associated lymphoid tissue (CALT) has been reported in various species, its cell composition remains unclear. Herein, we aimed to elucidate the morphology and development of the feline ocular immune system by examining the lacrimal tract and its associated tissues in adolescent (7- to 8-month-old) and fetal cats. The feline lacrimal tract, composed of the lacrimal canaliculi, lacrimal sac, and nasolacrimal duct, was visualized using CT. Histologically, a small lymphocyte aggregate, identified as LDALT, was observed exclusively along the lacrimal canaliculus in one of the four adolescent cats. In contrast, extensive development of the CALT was observed in tissues surrounding the openings of the lacrimal tract, particularly on the cornea-facing side of the third eyelid. CALT is characterized by CD20⁺ B cell aggregates surrounded by CD3⁺ T cells, including a small subset coexpressing CD20 and CD3. Neither LDALT nor CALT was observed in late gestational fetuses. In conclusion, CALT appears to contribute more significantly than LDALT to feline ocular immunity. Furthermore, given the pro-inflammatory nature of both CALT and CD3⁺CD20⁺ cells, our findings suggest that CALT is involved in the pathology of feline conjunctivitis.

Bovine coronaviruses (BCoVs) cause gastrointestinal and respiratory symptoms in cattle, resulting in economic losses in the industry. The virus strains are endemic in many countries worldwide, including Japan. As recent epidemiological data on BCoVs in Japan are limited, we conducted a survey in Chiba Prefecture, where no such survey has been conducted before, using nasal swab or lung samples collected from 105 cattle with respiratory symptoms during 2020-2022. The rate of BCoV RNA positivity determined using real-time RT-PCR was 43.8% (46 samples), among which 20 strains were successfully isolated. Phylogenetic analysis based on the polymorphic sequence region of the spike gene classified the detected strains into the Japan G3 or G4 genotypes. Therefore, in contrast to previous report that BCoVs of the G3 genotype may have gone extinct in Japan, our results suggest that the Japan G3 and G4 genotypes coexist and have spread in Chiba Prefecture, causing respiratory disease in cattle.

ELISA antibody titers against Rhodococcus equi strain ATCC 6939 were measured in serum samples collected from 644 horses aged 1-21 years at 13 provinces and the capital of Mongolia, of which 631 (98%) samples showed values of approximately zero. The mean antibody titers in the 14 areas ranged from -0.08 to -0.01. Nine samples (1.4%) exhibited titers of 0.1-0.2, and surprisingly, four horses (0.6%) each aged 2, 5, 8, and 9 years demonstrated positive values in the range of 0.3-0.8. Considering the age resistance characteristic of this disease, the positive horses were hypothesized to exhibit nonspecific reactions against R. equi antigens, potentially attributable to underlying infections, such as Corynebacterium pseudotuberculosis infection, or others as unidentified factors. Further investigation of these positive sera could potentially reveal previously unknown infectious diseases.

Influenza D virus (IDV), a respiratory pathogen primarily affecting cattle, is known to have the potential to infect a wide range of animal species. In this study, a novel IDV strain, designated D/JLSL and belonging to the D/Yama2019 lineage, was isolated from a stillborn bovine fetus. Phylogenetic analysis revealed that all 7 genomic segments of the D/JLSL cluster within the D/Yama2019 lineage. Notably, the hemagglutinin-esterase-fusion (HEF) protein of D/JLSL exhibits 7 amino acid substitutions compared with the 3 previously characterized D/Yama2019 strains. These findings suggest that D/JLSL may represent a distinct variant within the D/Yama2019 lineage. This study marks the first identification and genetic characterization of IDV from the D/Yama2019 lineage in a stillborn bovine fetus, highlighting the need for further surveillance to elucidate its prevalence and biological properties.