[Cryopreservation of in vitro fertilized embryos from transgenic rat by ultrarapid freezing].

We cryopreserved pronuclear stage-embryos from the Transgenic rats produced by introducing the rat GH antisense transgene, by ultrarapid freezing. The embryos were obtained by fertilization in vitro with the sperm of homozygous males for the transgene. After thawing of a part of cryopreserved embryos (97 embryos), the 40 embryos (41%) were morphologically normal, and were transferred to oviducts of recipients. All four live young (10%) obtained (one male and three females) preserved the transgene and exhibited dwarfism. We also produced the homozygous transgenic rats after brother-sister mating of those young. These results demonstrated the possibility of the cryopreservation of embryos by ultrarapid freezing for sustaining transgenic rat line.

Functioning parathyroid lipoadenoma--report of four cases: clinicopathological and ultrasonographic features.

Functioning parathyroid lipoadenoma (hamartoma) composed of abundant adipose or myxomatous stroma and epithelial cell nests is an unusual cause of primary hyperparathyroidism. We report herein four new cases. None of them belongs in the category of multiple endocrine neoplasia or familial hyperparathyroidism. The clinical manifestations and the laboratory findings are indistinguishable from those of the usual forms of primary hyperparathyroidism. Ultrasonography of the neck demonstrated an enlarged parathyroid gland as a hyperechoic mass in the two patients tested. At operation in each case, a single enlarged gland was found and resected, the weight being 3, 0.3, 0.45 and 1 g, respectively. The patients are normocalcemic 1 to 10 years after surgery. Pathological examination disclosed that the lesions were consistent with lipoadenoma or its variants. On reviewing 20 cases of functioning lipoadenoma which were reported in the literature, including the present cases, we found that the size of the tumors varied and a functioning lipoadenoma is hence by no means unusually large as previously reported. Without knowledge of this specific clinicopathologic entity, the lesion may be overlooked at the preoperative localization study and misdiagnosed as a normal or hyperplastic parathyroid.