Abnormal development of nephrons in claudin-16-defective Japanese black cattle

The kidneys of 37 Japanese Black calves aged 2 to 65 months diagnosed with Claudin 16 (CL-16) defect by the DNA-based test were examined pathologically. The animals exhibited clinical symptoms such as growth impairment, renal failure, overgrowth of hooves, and anemia at a young age. There was no correlation between the time of onset and age. Kidney weights relative to body weight were similar to those in normal animals, but both kidney net weights and size were reduced due to atrophy in animals that showed severe renal dysfunction. Histopathological examination of the kidneys showed reduction in the number of glomeruli, compensatory hypertrophy of glomeruli and tubules, and glomerular and tubular atrophy accompanied by interstitial fibrosis and lymphocytic infiltration. Glomeruli were clearly less in number in the kidneys of CL-16-defective animals than those of normal animals even in the cases with mild lesions. A small number of immature glomeruli and tubules were also detected, suggesting that there were fewer nephrons developed at birth in CL-16-defective animals. It was suggested that a defect of the CL-16 gene is involved in the "abnormal development of nephrons". Immunohistopathological examination of the kidneys showed that the epithelium of thick ascending limb of Henle was stained with anti-CL-16 antibody in the control animals, but not in the affected animals, suggesting a defect of CL-16 in the epithelium of renal tubules in the affected animals.     

Inhibitory function of whey acidic protein in the cell-cycle progression of mouse mammary epithelial cells (EpH4/K6 cells)

Although the biological role for whey acidic protein (WAP) in milk has been suggested, its true function is not known. This paper describes evidence for WAP function in the cell-cycle progression of EpH4/K6 (EpH4), mammary epithelial cells in vitro. The forced expression of exogenous WAP significantly impaired the proliferation of EpH4 cells, whereas it did not affect that of NIH3T3 cells. Apoptosis was not enhanced in the EpH4 cells with stable expression of WAP (WAP-clonal EpH4 cells). The analyses of BrdU incorporation revealed that forced WAP expression significantly reduced incorporation of BrdU in WAP-clonal EpH4 cells compared with control cells transfected with empty plasmid. Among G1 cyclins, the level expression of cyclins D1 was significantly lower in the WAP-clonal EpH4 cells than in control cells. The inhibitory action of WAP on the proliferation of EpH4 cells was enhanced by the presence of extracellular matrix (ECM), but not by the presence of a single component comprising ECM. The cultured medium of WAP-clonal EpH4 cells inhibited the proliferation of control cells without WAP expression. The present results indicate that WAP plays a negative regulatory role in the cell-cycle progression of mammary epithelial cells through an autocrine/paracrine mechanism.     

Transsphenoidal hypophysectomy for four dogs with pituitary ACTH-producing adenoma

Four dogs diagnosed as pituitary-dependent hyperadrenocorticism were treated with transsphenoidal hypophysectomy and postoperative hormone supplementation therapy. On histological examination of the resected tissues, the tumors were ACTH-producing adenoma of the anterior lobe. Clinical signs such as alopecia and calcinosis cutis, as well as endocrinological abnormalities, were markedly alleviated after surgery. The clinical courses of these 4 dogs suggest that transsphenoidal hypophysectomy may be a useful treatment for pituitary-dependent hyperadrenocorticism.     

Penetration of drug resistance in Escherichia coli isolated from laboratory animals

A total of 713 strains of fecal Escherichia coli (E. coli) isolated from laboratory animals in the colonies of 4 research laboratories and 4 commercial breeders in Japan in 1994 were examined in regard to resistance to 8 antibacterial agents. The incidence of resistance to sulfadimethoxine (Su), streptomycin (Sm), ampicillin, cephaloridine, tetracycline, chloramphenicol, kanamycin, and gentamicin was 99.9%, 32.5%, 6.7%, 0.7%, 7.0%, 2.6%, 6.6% and 0.7%, respectively. These results indicated that Su and Sm resistance are penetrating into normal E. coli strains isolated from laboratory animals.     

Characterization of Staphylococcus aureus strains isolated from bovine mastitis in Japan

Fifty-three strains of Staphylococcus aureus isolated from cows affected with mastitis from 21 prefectures in Japan were characterized by phenotypic and genotypic methods. Thirty-three (62.3%) strains showed biotype K-beta+CV:A, coagulase type VI, and sensitivity to bovine phages of group III or IV. These 33 strains could be subdivided into two groups on the basis of the production of staphylococcal enterotoxins (SEs) and on toxic shock syndrome toxin-1 (TSST-1). By pulsed-field gel electrophoresis, the 16 SEC- and TSST-1-producing strains showed similar patterns that differed by only a few fragments, suggesting that they were genetically closely related. Fifteen of 17 non SEC-producing strains which did not produce any other SEs and TSST-1 were genetically different from the SEC-producing strains and showed genetic diversity.     

Incidence of Salmonella infection in healthy dogs in Gifu Prefecture,Japan

A total of 1,013 feces samples and 8 mesenteric lymphonodus samples obtained from apparently healthy dogs were examined for the incidence of salmonella infection. One strain of S. typhimurium (ST) was isolated from feces of one dog, and S. enteritidis (SE) was isolated from the mesenteric lymphonodus of one dog. Sera obtained from 330 apparently healthy dogs were examined for Salmonella antibodies using an ELISA with heated whole cells of SE and ST. Fifty-one of the 330 serum samples were considered to be positive for salmonella antibodies, including 12 which were SE-positive and 39 which were ST-positive. These results indicate that dogs cause possible environmental problems as Salmonella carriers.     

Molecular biology and biotechnology for reduction of Fusarium mycotoxin contamination

Fusarium head blight (FHB) is a devastating disease of important cereal crops resulting in significant yield loss and mycotoxin contamination. Persistent outbreaks of FHB in Europe and North America have led to various efforts to understand the mechanisms of resistance to this disease and mycotoxin biosynthesis. In this minireview, we summarize basic and applied studies conducted in our laboratories into reducing mycotoxin contamination in FHB.