N -ethyl- N -nitrosourea induces retinal photoreceptor damage in adult rats

Seven-week-old male Lewis rats received a single intraperitoneal injection of N-ethyl-N-nitrosourea (ENU) (100, 200, 400 or 600 mg/kg), and retinal damage was evaluated 7 days after the treatment. Sequential morphological features of the retina and retinal DNA damage, as determined by a TUNEL assay and phospho-histone H2A.X (γ-H2AX), were analyzed 3, 6, 12, 24 and 72 hr, 7 days, and/or 30 days after 400 mg/kg ENU treatment. Activation of the nuclear enzyme poly (ADP-ribose) polymerase (PARP) was analyzed immunohistochemically by poly (ADP-ribose) (PAR) expression in response to DNA damage of the retina. All rats that received ≥ 400 mg/kg of ENU developed retinal degeneration characterized by the loss of photoreceptor cells in both the central and peripheral retina within 7 days. In the 400 mg/kg ENU-treated rats, TUNEL-positive signals were only located in the photoreceptor cells and peaked 24 hr after ENU treatment. The γ-H2AX signals in inner retinal cells appeared at 24 hr and peaked at 72 hr after ENU treatment, and the PAR signals selectively located in the photoreceptor cell nuclei appeared at 12 hr and peaked at 24 hr after ENU treatment. However, degeneration was restricted to photoreceptor cells, and no degenerative changes in inner retinal cells were seen at any time points. Retinal thickness and the photoreceptor cell ratio in the central and peripheral retina were significantly decreased, and the retinal damage ratio was significantly increased 7 days after ENU treatment. In conclusion, ENU induced retinal degeneration in adult rats that was characterized by photoreceptor cell apoptosis through PARP activity.     

Anticoagulant-induced Alterations in Pig Platelets

Application of an anticoagulant to prevent clotting is a prerequisite for the retention of morphological integrity of platelets in blood samples. Among the anticoagulants used for the collection of blood from veterinary animals, are heparin, the oxalate salts (sodium and potassium) and di-sodium and tri-sodium citrates. In a study on the effects of anticoagulants on platelet morphology, it was noted that oxalates caused severe morphological distortion in platelets. It is hypothesized that the membranous extensions, pseudopodia and loops detected in the platelets in oxalated blood may have been triggered by the irreversible formation of calcium oxalate salts which in turn alter the intracellular electrolyte balance.     

Changes in developmental duration of direct-seeded rice in a well-drained paddy field in response to late planting

We investigated changes in the developmental duration of rice cultivars with a wide range of maturities in response to late planting. Elucidating the relationship between cropping season and the progress of growth stages is important for establishing direct-seeded cultivation and creating growth models. Late planting of the intermediate to late maturing cultivars Akidawara and Hoshijirushi decreased the time from emergence to panicle formation and decreased the cumulative effective temperature (CET) and cumulative effective soil temperature (CEST). In the very early maturing cultivars Ichibanboshi and Fusakogane, the changes in number of days, CET, and CEST from emergence to panicle formation with late planting were small. From emergence to heading and maturity, the number of days, CET, and CEST of many cultivars tended to increase until mid-May and then decreased. The changes in the number of days, CET, and CEST caused by late planting were greater for the intermediate to late maturing cultivars than for the very early maturing cultivars. The differences between cultivars were greatest with early May sowing, and then decreased with later planting. Short-day condition revealed significant differences in the duration of vegetative growth and CET among cultivars, but long-day condition erased these differences. These results demonstrate that the photosensitivity and thermosensitivity of cultivars are especially important in crop planning and for creating growth models of direct-seeded rice.     

Effects of prescription diet on dealing with stressful situations and performance of anxiety-related behaviors in privately owned anxious dogs

The objectives of this study were to evaluate the effects of a diet (CALM CANINE) supplemented with alpha-casozepine and L-tryptophan on the stress response of anxious dogs with a focus on anxiety-related behavioral parameters and physiological parameters. Forty-four privately owned dogs were first fed with the control diet, followed by the study diet, each for an 8-week period, with a transitional period of 1 week between the diets. After 7 weeks on a particular diet, owners reported their dogs' behavior by filling out a questionnaire. Using the Canine Behavioral Assessment and Research Questionnaire, the effect of the study diet was found to be significant for 4 anxiety-related behavioral parameters, possibly mirroring a placebo effect. After 7 weeks on each diet, the urine cortisol-to-creatinine ratio (UCCR) was measured to assess the stress response to a visit to a veterinary practice for toenail clipping. UCCR was measured to complement the interpretation of behavioral data with regard to the stress susceptibility of the dogs. A positive correlation was found between baseline UCCR, as measured in the home situations, and poststressor UCCR. The stressor-induced increase was significantly lower in the dogs when they were fed the study diet than earlier when they were fed the control diet. The supplementation of casozepine or the proportion of protein in a given diet could have been a determining factor. The study diet seems to improve the ability of an individual to cope with stress and may reduce anxiety-related behavior in anxious dogs.     

Ultrastructural alterations of the myocardium of rats fed rapeseed oils.

Ultrastructural studies were conducted on the myocardium of rats fed corn oil, Tower RSO (0 . 88 per cent EA), 1788 RSO (3 . 6 per cent EA) and Target RSO (38 . 9 per cent EA) supplemented diets for 18 weeks. Cardiac myocytes of Tower RSO-fed rats showed some loosening of myofibrils and a slight increase in the number of mitochondria, few of which had lost their cristae. Large intravascular lipid droplets were observed in the myocardium of rats fed the 1788 RSO diet, as well as some small lipid droplets which were seen in close association with mitochondria. There was an apparent increase in the number of mitochondria of both normal and giant size. Many of the mitochondria exhibited distortion of shape and degeneration of cristae. The matrix of megamitochondria contained vesicles and electron-dense floccular inclusions and at times electron-lucent lipid-like material. The degenerative changes of mitochondria were most pronounced in the Target RSO group, where some megamitochondria showed a complete loss of cristae and a replacement of matrix with lipid-like material. These observations suggest that both intravascular lipid globules and the mitochondrial alterations are possible contributory factors involved in the development of cardiac lesions in RSO-fed rats.     

Introduction of a point mutation in the KRAS gene of in vitro fertilized porcine zygotes via electroporation of the CRISPR/Cas9 system with single-stranded oligodeoxynucleotides

This study aimed to investigate the efficiency of KRAS gene editing via CRISPR/Cas9 delivery by electroporation and analyzed the effects of the non-homologous end-joining pathway inhibitor Scr7 and single-stranded oligodeoxynucleotide (ssODN) homology arm length on introducing a point mutation in KRAS. Various concentrations (0–2 µM) of Scr7 were evaluated; all concentrations of Scr7 including 0 µM resulted in the generation of blastocysts with a point mutation and the wild-type sequence or indels. No significant differences in the blastocyst formation rates of electroporated zygotes were observed among ssODN homology arm lengths, irrespective of the gRNA (gRNA1 and gRNA2). The proportion of blastocysts carrying a point mutation with or without the wild-type sequence and indels was significantly higher in the ssODN20 group (i.e., the group with a ssODN homology arm of 20 bp) than in the ssODN60 group (gRNA1: 25.7% vs. 5.4% and gRNA2: 45.5% vs. 5.9%, p < .05). In conclusion, the CRISPR/Cas9 delivery with ssODN via electroporation is feasible for the generation of point mutations in porcine embryos. Further studies are required to improve the efficiency and accuracy of the homology-directed repair.     

A piglet with concurrent polioencephalomyelitis due to porcine teschovirus and postweaning multisystemic wasting syndrome

A piglet developed respiratory distress followed by difficulty in standing and unsteady gait. The lesions were characterized by polioencephalomyelitis with the predominant distribution in the brain stem, as well as lymphocyte depletion and histiocyte infiltration with cytoplasmic inclusion bodies in the lymphoid tissues throughout the body and interstitial pneumonia. Porcine teschovirus (PTV) antigens were found in the former lesions and porcine circovirus 2 (PCV2) in the latter two lesions. PTV genes were detected from the diencephalon. The results suggest that the piglet was concurrently affected with polioencephalomyelitis due to PTV and postweaning multisystemic wasting syndrome (PMWS) associated with PCV2. They also suggest that the immunosuppressive condition developing in PMWS may have facilitated the infection of the brain with PTV.     

Spontaneous extraskeletal osteosarcoma with various histological growth patterns in the abdominal wall of an ICR mouse

Extraskeletal osteosarcoma is extremely rare in mice. This case report demonstrates a spontaneous murine extraskeletal osteosarcoma that exhibited various histological growth patterns in an ICR mouse. At necropsy, the tumor mass was located in the abdominal wall and was 45 × 30 × 25 mm in size. Histopathologically, the tumor showed the following four growth patterns: a solid pattern of polygonal cells embedded in an osteoid eosinophilic matrix with calcification, an irregular sheet pattern of short spindle cells accompanying some eosinophilic multinucleated cells, a fascicular pattern of spindle cells and a cystic pattern lined by short spindle cells. Immunohistochemically, most of the tumor cells were positive for vimentin, proliferating cell nuclear antigen and osterix. The multinucleated cells mentioned above were desmin positive and were regarded as regenerative striated muscles but not tumor cells. Since no clear continuity with normal bone tissues was observed, the tumor was diagnosed as an “extraskeletal osteosarcoma.”     

Ultrastructural and immunologic characteristics of mouse x cattle xenogeneic hybridomas originating from bovine leukemia virus-infected cattle

Nine percent of xenogeneic hybridomas originating from a bovine leukemia virus (BLV)-infected cow secreted monoclonal IgM antibodies with multispecific reactivity. Similar reactivity was evident in some antibodies with an unusually long (> 50 amino acids) third complementarity-determining region of the heavy chain. Electron microscopy of hybridomas demonstrated the presence of c-type virus particles consistent with polymerase chain reaction detection of BLV env gene. Some hybridomas contained dilated rough endoplasmic reticulum and cisternae filled with moderately electron-dense granular substance compatible with plasma cells at presecretory stage. The number of chromosomes in xenogeneic hybridomas corresponded to the sum total of mouse and bovine chromosomes. None of the hybridomas showed polyploidy. The immunochemical and genetic analysis of stable bovine immunoglobulin-secreting xenogeneic hybridomas confirms that BLV infection causes polyclonal B cell activation regardless of antigen specificity. Presence of c-type particles in hybridomas suggests that T cell-derived cytokines are not required for sustained BLV expression.