Differentiation and elimination of uterine natural killer cells in delayed implantation and parturition mice

To clarify the roles of uterine natural killer (uNK) cells in implantation and parturition, differentiation and elimination of uNK cells in the pregnant uterus was examined using artificial delayed implantation (DI) and delayed parturition (DP) mice. To prepare DI mice, pregnant mice were ovariectomized on the third day of pregnancy (D3) and treated with 2 mg progesterone daily. The same amount of progesterone was administered on D15 or D17 of normal pregnant mice at 24 h intervals until sampling to prepare DP mice. The uNK cells contained PAS-positive granules on D8 in DI mice. The uNK cells in DI mice were smaller in size, and differentiation of these cells was delayed compared to those of the control mice. From D19 to D21 in DP mice, the metrial gland was well developed and uNK cells were present. The number of uNK cell granules decreased on D21, and there were no uNK cells in the normal pregnant mice. This result suggests that differentiation of uNK cells is not directly related to implantation, but elimination of these cells is closely involved in parturition.     

Factor XI mutation in a Holstein cow with repeat breeding in Japan

Factor XI deficiency is an autosomal recessive coagulopathy in Holstein cattle. Affected cows have a tendency to show repeat breeding. Forty repeat breeding Holstein Friesian cows were selected and tested for the Factor XI mutation. Genomic DNA was isolated from the blood of the cows (n=40). Exon 12 of the Factor XI gene of the cows was amplified by PCR. One repeat breeding cow was heterozygous to the Factor XI mutation as indicated by the presence of two DNA fragments of 320 bp and 244 bp. The insertion of the 76 bp in the heterozygous cow was confirmed by DNA sequencing. The heterozygous cow was in her fourth lactation. She gave birth to male twins at the last calving. She was inseminated artificially four times after the last calving. Factor XI deficiency in cattle has been reported in different countries. However, no case was reported in Japan. This might be the first to report Factor XI mutation in Holstein cattle in Japan.     

Detection of Mycoplasma hyopneumoniae in lung and nasal swab samples from pigs by nested PCR and culture methods

We examined nasal swab and lung homogenate samples collected from pigs experimentally and naturally infected with Mycoplasma hyopneumoniae for the detection of M. hyopneumoniae by the nested PCR (nPCR) and culture methods. In the 23 experimentally infected pigs, M. hyopneumoniae was commonly detected in nasal swabs by the nPCR and culture methods at 4 weeks after inoculation, and there was a significant correlation (P<0.01) between the titers of viable organisms in nasal swabs and in lung homogenates in the experimentally inoculated pigs. In the naturally infected pigs, on the other hand, discrepancies in detection were found between nasal swab and lung homogenate samples in 17 of 36 cases, although the presence of gross lung lesions correlated relatively well with the detection of organisms from the samples. Our results indicated that the diagnosis of mycoplasmal pneumonia by nPCR in individual pigs with nasal swabs is reliable under these experimental conditions. At present, nPCR with nasal swabs should only be used for monitoring the disease status at the herd level under field conditions.     

Immunohistochemical analysis of expression patterns of tumor necrosis factor receptors on lymphoma cells in enzootic bovine leukosis

Tumor necrosis factor-alpha (TNF-alpha) has been reported to be associated with the progression of lymphoproliferative neoplastic diseases and retroviral infections. Hence we examined immunohistochemically the expression patterns of TNF-receptors (TNF-RI and RII) on lymphoma cells derived from the 29 cases of enzootic bovine leukosis (EBL). Lymphomas obtained in 29 animals with EBL were histopathologically classified into three types: diffuse mixed type (10 cases), diffuse large type (9 cases), and diffuse large cleaved type (10 cases). Immunohistochemically using a monoclonal antibody to a bovine lymphocyte surface antigen, the lymphomas were classified into three phenotypes: B-1a (CD5+/CD11b+), B-1b (CD5-/CD11b+) and B-2 (conventional B) (CD5-/CD11b-). Interestingly, the lymphoma cells in all animals expressed TNF-RII, but not TNF-RI. Although, in EBL, lymphoma cells of which the histopathological and immunological property differs has been formed, the expression patterns of TNF-Rs had the universality in all lymphoma cells. TNF-RII, which induces cell proliferation, was expressed but TNF-RI, which induces cell apoptosis was not expressed on all lymphoma cells, suggesting that TNF-Rs play an important role in the malignant proliferation of B cells and formation of lymphomas in EBL.     

Histological study of granulated metrial gland (GMG) cells in beige (DA-bg/bg) rats

To clarify the roles of granulated metrial gland (GMG) cells for successful pregnancy in rats, GMG cells in beige rats (genotype: DA-bg/bg), whose NK cells show lysosomal dysfunction because of abnormalities in cytoplasmic granules, were examined in mid- and late-pregnancy by light and electron microscopies. The GMG cells of beige rats were significantly less in number than those of the two controls (genotypes: DA-bg/+ and DA-+/+) in mid- and late-pregnancy, and this accompanied a low reproductive performance in the beige rats. The size of intracellular granules in the GMG cells of the beige rats was larger than for the two controls on each corresponding day of pregnancy. These results suggest that the activity of rat GMG cells and peripheral NK cells might be influenced by the beige gene, which is involved in reproductive performance.