Relationship between serum TNF activity and insulin resistance in dairy cows affected with naturally occurring fatty liver

To clarity the relationship between tumor necrosis factor (TNF) and insulin resistance in dairy cows affected with fatty liver, naturally occurring cases were investigated. The affected cows were classified into following three groups according to histopathologic findings of the liver: mild fat droplet deposition (group 1; n=11), severe fat droplet deposition (group 2; n=10), and cloudy swelling (group 3; n=8). Serum TNF activities in Group 2 (8.67 +/- 2.16 U/ml) and Group 3 (11.65 +/- 1.92 U/ml) were significantly higher than that in Group 1 (3.57 +/- 0.81 U/ml) (p<0.05). The insulin-tolerance tests showed that the insulin-stimulated glucose disposal rates (GDR) in Group 2 (27.6 +/- 7.8%) and Group 3 (15.8 +/- 9.1%) were significantly lower than that in Group 1 (41.7 +/- 9.8%). There was a significant negative correlation between serum TNF activity and GDR in affected cows (r=-0.56, p<0.01). These results indicate that serum TNF activity is correlated with insulin resistance in cows with fatty liver.     

Spontaneous pinealoma in a male Crj:CD (SD) IGS rat

A pinealoma (benign) was found in a 61-week-old male Crj:CD (SD) IGS rat. The neoplasm was located between the cerebral hemispheres and the cerebellum. Histologically, the tumor cells consisted of two cell types: large, pale-staining cells and small dark-staining cells. A fibrovascular stroma divided the tumor cells into incomplete lobules or nest structures. Relatively numerous mitoses were noted in the tumor cells. Ultrastructurally, the tumor cells contained dense-cored vesicles, approximately 120 nm in diameter.     

Effects of chicken thymic stromal cells on the growth and differentiation of thymocytes in vitro

We examined contact-mediated effects of chicken thymic stromal cells (TSC) on thymocyte differentiation by co-cultivation of these cell populations. The primary cultures of TSC isolated from thymus mainly have consisted of epithelial cells which were polygonal in shape, possessed long processes and expressed MHC class II antigen. When thymocytes were co-cultured with TSC, 60% to 70% of thymocytes attached to TSC and some of them engulfed underneath TSC. These attached thymocytes were CD4-CD8- and CD4+CD8+ subsets and expressed alpha/beta TCRhigh or gamma/delta TCRlow. Some of the thymocytes attaching to TSC showed an increase of intracellular and nuclear density, fragmentation of cytoplasm and nuclei, and DNA fragmentation. And also, thymocytes attaching to TSC contained a higher percentage of cycling (S and G2 + M phase) cells than nonattaching cells. These results indicate that specific subsets in thymocytes selectively bind to TSC and undergo apoptotic death or proliferation because of interaction with TSC. Chicken TSC may play an important role in thymic differentiation by direct contact within the thymus as in mammals.     

Effects of a macrolide antibiotic on enamel formation in rat incisors--primary lesion of ameloblast at the transition stage

A novel macrolide antibiotic was administered orally to 5-week-old Jcl:Wistar rats at a dose of 5,000 mg/kg/day for 5 weeks, and then a half of animals were maintained without any treatment for 10 weeks. A white discolored lesion with horizontal stripes developed on the surface of the upper and lower incisors after dosing for 4 weeks, and these macroscopical incisal lesions disappeared with the eruption in 4 weeks after stop of administration. Histopathologically, increase in number of karyopycnosis of ameloblast at the transitional stage, vacuolar degeneration of ameloblast and cystic change in the maturation stage, and impaired iron pigment secretion at the pigmentation stage were observed. Microradiography, calcio-traumatic zones, which means hypocalcification, were observed on the superficial layer of enamel. These results suggest that the primary lesion induced by a novel macrolide antibiotic is the increased karyopycnosis of ameloblast at the transitional stage, and followed by later stage.     

Relation between phenotype of tumor cells and clinicopathology in bovine leukosis

Thirty-three cases of enzootic bovine leukosis (EBL) and 14 cases of sporadic bovine leukosis (SBL) were examined by immunohistochemistry using 6 monoclonal antibodies against leukocyte differentiation molecules of bovine leukocytes. There were 17 cases of B-1a cell type, 10 cases of B-1b cell type and 6 cases of B-2 cell type in EBL, and 5 cases originating from B cells (B-2 cell type) and 9 cases originating from immature T cells in SBL. The average age for the EBL cases of B-1a cell type was 8.6 years, B-1b cell type was 6.5 years, and of B-2 cell type was 4.5 years. In cases of SBL, immature T cell type patients were younger than B-2 cell type ones. The lymphoma originating from B cells differed from that originating from T cells in morphology. In T cell tumors, the nucleus of tumor cells was round, the edge of the cytoplasm obvious, and tumor cells were sporadically present and proliferated. When compared with T cells, the region among B cells was obscure. But, there was no relation between phenotype and the histologic classification of tumor cells. In EBL, beyond the lymph node, tumors of B-1a and B-1b types had developed in the heart and abomasum, and those of the B-2 type tended to occur in liver. In SBL, B-2 type and T type cells formed tumors in the liver, kidney, thymus, and one case of T-cell type tumor formed on the skin. We would like to propose a new classification of bovine leukosis as EBL, calf type B-cell lymphoma, juvenile T-cell lymphoma and skin type T-cell lymphoma.     

Serum activities of tartrate-resistant acid phosphatase and bone specific alkaline phosphatase as indices of bone metabolism in the cow

The correlation between the serum hydroxyproline concentration and serum activity levels of TRAP and BALP was examined in 41 cows. The correlated coefficient (r) was 0.6391 for TRAP and 0.3147 for BALP, respectively. Judging from the significant correlation to the serum hydroxyproline concentration, serum TRAP activity is an index for bone metabolism in cows. Serum TRAP activity was therefore measured in 205 healthy cows (2-9 years old) in order to observe the changes in bone resorption with aging and milk production. TRAP levels differed slightly between group A (< or =4 yrs) and B (5 yrs< or =) at the same stage of lactation. The activity levels rose slightly at the height of lactation stage and during the dry stage.     

Protective effect of vaccination with culture supernate of M. hyopneumoniae against experimental infection in pigs

The protective activity of Mycoplasma hyopneumoniae inactivated vaccine prepared from sedimented whole cells and cell-free culture supernates was evaluated experimentally using hysterectomy-produced, colostrum-deprived pigs in which mycoplasmal pneumonia had been induced. The culture supernate vaccine containing less than 10(1) colour-changing units (CCU)/0.2 ml of M. hyopneumoniae significantly (P < 0.05) reduced the percentage of lung lesions compared to controls (3.2 +/- 3.9 vs. 12.2 +/- 2.2%), whereas the sedimented whole cells vaccine containing 10(10) CCU/0.2 ml of organisms provided variable protection (18.7 +/- 16.5 vs. 12.2 +/- 2.2%). Serum from the pigs vaccinated with culture supernate reacted with six protein bands of 97, 89, 65, 46, 42 and 41 kDa by immunoblot analysis. From these results, we conclude that vaccination with culture supernate of M. hyopneumoniae can provide protection against M. hyopneumoniae infection and that these antigens in the culture supernate may be closely related to the reduction of lung lesions.     

Poxvirus infection in Nile crocodiles (Crocodylus niloticus)

An outbreak was encountered of numerous yellowish cutaneous nodules in one- to two-year-old farmed Nile crocodiles (Crocodylus niloticus) in Kasaba Bay Crocodile Farm at Lake Tanganyika in Zambia during 1988. Out of 4000 crocodiles of different age groups, 300 yearlings were affected and 82 of those affected died. The lesions were prominent on the head, especially around the eyelids, the nostrils, both sides of the mouth, ventral neck, ventral pale belly, limbs and the root of the tail. Histologically, the epidermal lesions revealed large focal areas of marked acanthosis accompanied by hyperkeratosis and parakeratosis. In the prickle cells, there were multiple small neutrophilic granular inclusions and large eosinophilic homogeneous cytoplasmic inclusions. Electron microscopically, there were numerous poxvirus particles and matrices in the cytoplasm of many prickle cells. Dark blue homogeneous cytoplasmic inclusions in toluidine blue sections consisted of an electron opaque matrix with mature viral particles (160 x 200 x 230 nm). Furthermore, there were clumps of granular matrix containing immature viral particles (200 x 399 nm) in the cytoplasm. Various features of viral developing processes were observed.     

Effects of light and microsite conditions on tree size of 6-year-old Cryptomeria japonica planted in a group selection opening

We examined the extent to which direct and indirect measures of light and microsite conditions could explain variation in tree height and diameter at the base of 6-year-old Cryptomeria japonica trees planted in a group selection opening of about 0.32 ha on a steep slope at Shiiba, Miyazaki Prefecture, southern Japan. We first used the gap light index (GLI) and soil thickness (ST) as directly measured indices. For an indirect measure of light, we used a between-cohort competition index (BCI) estimated from the position and total height of residual trees. For indirect measures of microsite, we examined topographic indices (slope, plan and profile curvature, average slope gradient, and relative elevation) derived from digital elevation models (DEMs) with different resolutions ranging from 2 to 10 m. The multiple linear regression using GLI and ST explained about 45% of variation in tree size, while simple regression using only GLI explained about 35%. The contribution of ST was about half of GLI. The multiple regressions using BCI and the topographic indices did not explain any more variation than using BCI alone (R ² of about 0.26). We conclude that microsite conditions with shallower soil and steeper slope have negative effects on tree growth in group selection openings, although the relative importance is smaller than light conditions. More comprehensive studies considering several openings with more heterogeneous topography including different species are needed to generalize our growth prediction using the indirect measures, which are useful for practical forest management.