Despite the high degree of homology (91%) between the nucleotide sequences of the Friend-mink cell focus-forming (MCF) and the Moloney murine leukemia virus (MuLV) genomic long terminal repeats (LTRs), the pathogenicities determined by the LTR sequences of the two viruses are quite different. Friend-MCF MuLV is an erythroid leukemia virus, and Moloney MuLV is a lymphoid leukemia virus. To map the LTR sequences responsible for the different disease specificities, we constructed nine viruses with LTRs recombinant between the Friend-MCF and Moloney MuLVs. Analysis of the leukemia induced with the recombinant viruses showed that a 195-base-pair nucleotide sequence, including a 75-base-pair nucleotide Moloney enhancer, is responsible for the tissue-specific leukemogenicity of Moloney MuLV. However, not only the enhancer but also its downstream sequences appear to be necessary. The Moloney virus enhancer and its downstream sequence exerted a dominant effect over that of the Friend-MCF virus, but the enhancer sequence 4lone did not. The results that three of the nine recombinant viruses induced both erythroid and lymphoid leukemias supported the hypothesis that multiple viral genetic determinants control both the ability to cause leukemia and the type of leukemia induced.

Abstract. A 45-year-old woman was referred to our hospital because of discomfort in the cervical region. Laboratory findings revealed thyrotoxicosis with positive TSH receptor antibodies, but acute inflammatory data were absent. After three weeks the thyroid hormone levels spontaneously decreased to hypothyroid levels, and thyroidal radioactive iodine uptake (RAID) was below normal. A needlebiopsy specimen of the thyroid gland obtained two months later showed diffuse lymphocytic thyroiditis, and she was therefore diagnosed as having had painless thyroiditis.Two months after returning to euthyroidism, a second thyrotoxicosis developed. TSH receptor antibodies remained positive, but RAIU was slightly above normal, indicating Graves' hyperthyroidism.Treatment with antithyroidal drugs was commenced but was soon discontinued due to an allergic reaction. Although only f3-adrenergic antagonist was administered for treating the thyrotoxicosis, thyroid function was gradually normalized in parallel with the reduction in TSH receptor antibody. In this case, painless thyroiditis would be followed by Graves' disease and subsequent spontaneous remission.

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A new cell line derived from a woodchuck hepatocellular carcinoma serially transplanted in athymic nude mice has been established and named WH257GE10. The original tumor in the nude mouse system produces woodchuck hepatitis surface antigen and albumin. In addition, woodchuck hepatitis virus DNA is integrated into cellular DNA. Adaptation of the cells to the in vitro culture condition was completed after 15 months with the doubling time of 40 hr. The morphologic features of the cell by light microscopy are of an epithelial type. The modal chromosome number is 36 and the karyotype is mainly metacentric, similar to that observed in normal woodchuck liver cells. Ornithine and tyrosine aminotransferase activities were detected. Production of albumin was demonstrated in the cytoplasm by indirect immunofluorescence. Integration of woodchuck hepatitis virus DNA was shown by Southern blot analysis, although the secretion of woodchuck hepatitis surface antigen was not detected. This cell line provides an excellent in vitro model to study human hepatocellular carcinoma related to hepatitis B virus.

A new cell line derived from a woodchuck hepatitis surface antigen-positive woodchuck hepatocellular carcinoma has been established and named T3-HEP-W1. This new cell line was established directly from a primary woodchuck hepatocellular carcinoma. Adaptation of the cells to the in vitro culture condition was completed after 3 months, with the doubling time of 24 hr. The morphologic features of the cell by light microscopy were of an epithelial type. The modal chromosome number was 100. Ornithine and tyrosine aminotransferase activities were detected. Production of albumin was negative. Integration of woodchuck hepatitis virus DNA was demonstrated by Southern blot analysis, although the secretion of woodchuck hepatitis surface antigen was not detected. T3-HEP-W1 is quite different from the previously reported WH257GE10 cell line and provides another in vitro model for the study of human hepatocellular carcinoma related to hepatitis B virus.