Yolk sac tumour involving floor of mouth: case report.

Yolk sac tumour is a rare malignant tumour of germ cell origin that usually arises from the gonads. It is extremely rare in the head and neck. We present a case of a yolk sac tumour that involved the floor of the mouth in a 14-month-old Chinese girl. The diagnosis was confirmed by histological examination that showed characteristic Schiller-Duval bodies, and immunohistochemical examination that showed α-fetoprotein being expressed within the cytoplasm of the neoplastic cells. The patient died 4 months postoperatively. To our knowledge, this is the first case of a yolk sac tumour of the floor of mouth that has been reported in an English journal.

Molecular analysis of hypoxanthine phosphoribosyltransferase gene deletions induced by alpha- and X-radiation in human lymphoblastoid cells.

Mutations caused by exposure to X-radiation and to radon and its decay products were compared in the hprt gene of a human lymphoblastoid cell line. Thirty-one X-radiation-induced, 29 radon-induced, and 24 spontaneous mutants were recovered from cell cultures under identical conditions except for the exposure to radiation. Seven spontaneous point mutations were recovered and DNA sequenced. These mutations included three C:G-->T:A transitions. These spontaneous point mutations were located in the exon or splice donor regions of five of the nine hprt exons. Four X-radiation-induced and three radon-induced point mutations were also analyzed by DNA sequencing. The frequency of induced mutants at the D0 doses for radon and X-radiation respectively were 5 x 10(-6) and 4.5 x 10(-6). Deletions were the predominant mutations recovered from both radon- and X-irradiated cells. Eighty-one percent of the mutants from X-radiation-treated cultures, 86% of the radon-treated cultures, and 63% of the spontaneous mutants involved deletions. Deletions involving exon and intron DNA, as well as intron DNA alone, were found to inactivate the hprt gene and result in a selectable HPRT- phenotype. Among the deletion mutants, however, only 21% of the spontaneous mutants versus 55% of both the X-radiation- and radon-induced mutants exhibited loss of the entire hprt gene. More X-radiation-induced deletions than radon-induced deletions extended further than 800 bp in the telomeric direction from the hprt gene (six of 17 versus two of 17). The results show that at the human hprt locus of TK-6 cells the predominant kind of mutation indicative of exposure to both high LET alpha-radiation and low LET X-radiation is a large deletion, spanning the entire hemizygous hprt gene and extending into flanking sequences.

[Interceptive activity of epostane in pregnant rats and rhesus monkeys].

A complete interceptive action on pregnancy was shown after ig epostane (Epo) 48 and 96 mg/kg on d 10 of pregnancy in rats. ED50 (95% fiducial limits) of Epo was 20.7 (16.3-26.3) mg/kg. Epo 48 mg/kg ig on d12, 14 and 16 of pregnancy lowered rat plasma progesterone concentrations (P less than 0.05) and plasma corticosterone on d 16 of pregnancy (P less than 0.05). Epo 35 mg/(kg.d) was given ig on d 50-54 of pregnancy in rhesus monkeys. Vaginal bleeding was seen in all of the 6 treated monkeys. Complete expulsions of fetal and placental materials occurred in 5 of the treated monkeys, among which 2 aborted on d 53 and the other 3 on d 54 of pregnancy. Plasma progesterone concentrations of the treated monkeys were lowered on d 52, 53 and 54 of pregnancy (P less than 0.05) and plasma estradiol on d 51, 52, 53, 54 and 55 (P less than 0.05), while there were no significant differences in plasma hydrocortisone. Epo may be a valuable supplement to the existing methods of female contraception.