4,4',6,6'-Tetrabromo-2,2'-biphenyldiol mono(dihydrogen phosphate). A new agent for combating distomatosis

Embryolethal and teratogenic effects of bromofenofos in rats

Bromofenofos, an organophosphorus anthelmintic, was administered by gavage to rats as a single dose (50 mg/kg) on one of days 6 through 14 of pregnancy. The dams were killed on day 21, and the fetuses were removed, weighed and examined by routine teratological methods. A significant increase in fetal resorptions occurred after administration on days 9 through 13, with a maximum on day 10. Approximately 72% of the implants were resorbed after administration on day 10. Fetal body weights were significantly decreased when dams were treated on day 8 or later. The greatest decrease in fetal body weights was observed on day 10, when the fetuses weighed less than the controls by about 44% on the average. The incidence of fetuses with gross, skeletal and internal malformations was significantly increased on days 8 through 10, on days 8 through 11 and on days 8 and 9, respectively. Although various types of malformations were observed, most of them occurred on day 8, when no significant increase in fetal resorptions did occur. Cleft lip, short tail, brachygnathia, anal atresia, absence of genital tubercle, fused pelvic legs and perineal testicles were seen on day 8 as gross malformations. Skeletal malformations mainly affected the vertebrae and ribs. Major internal malformations on day 8 were hydronephrosis, hydroureter, anophthalmia, cleft palate, agenesis of the bladder and renal agenesis. Anophthalmia and/or microphthalmia were observed on days 8 through 10, with the highest incidence on day 9.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative embryolethal effect of bromofenofos and dephosphate bromofenofos in rats

Bromofenofos (BF) and dephosphate bromofenofos (DBF) were administered at equimolar doses to rats on day 10 of pregnancy. The dams were killed on day 21, and the fetuses were removed, weighted and examined by routine teratological methods. BF caused a significant increase in fetal resorptions at 58.2 mg/kg. Approximately 69% of the implants were resorbed at this dose level. In rats given DBF equimolar to 58.2 mg/kg BF, the resorption rate was 81.9%. Administration of BF resulted in a dose-dependent decrease in fetal body weights which was significant at 29.1 mg/kg or more. DBF caused a significant decrease in fetal body weights, beginning at 25.1 mg/kg equimolar to 29.1 mg/kg BF, and the decreased fetal body weights were almost the same between BF and DBF. BF at 58.2 mg/kg induced significant gross and skeletal malformations, with incidences of 35.6 and 27.6%, respectively. In rats given DBF equimolar to 58.2 mg/kg BF, gross and skeletal malformations were seen in 54.5 and 61.5% of the fetuses, respectively. There were similarities in the types of malformations observed between BF and DBF. Both compounds induced no significant internal malformations. It was concluded from these results that the embryolethal and teratogenic effects of BF is due to its metabolite, DBF, which cannot respond to cholinesterase inhibition.

Embryolethality of bromofenofos in rats

Bromofenofos, an organophosphorus anthelmintic, was suspended in deionized water and administered once daily to pregnant rats by gastric intubation on days 8 through 15 of pregnancy in doses of 0, 2.5, 5, 10 and 20 mg/kg. The dams were killed on day 21 of pregnancy, and the number of implants, resorptions and live fetuses was counted. All fetuses were weighed and examined by routine teratological methods. As the results showed, this compound was highly embryolethal in the 20 mg/kg group; approx. 91% of the implants were resorbed at this dose level. Although none of the fetuses were externally malformed in any group, the incidence of skeletal and internal malformations was significantly increased in fetuses in the 20 mg/kg group. Skeletal malformations observed at this dose level were bipartite vertebral centra and wavy ribs. Internal malformations involved anophthalmia, hydronephrosis and hypoplasia of the uterus.

2',3'-seco pyrimidine nucleosides and nucleotides, including structural analogues of 3':5'-cyclic CMP and UMP, and their behaviour in several enzyme systems

Cyclization of 2',3'-seco-5'- CMP and UMP with dicyclohexylcarbodiimide leads to 2',3'-seco-3':5'- cCMP and cUMP, formal structural analogues of 3':5'- cCMP and cUMP. POCl3 phosphorylation of 2',3'-secocytidine gave the same product in 50% yield, plus three additional seco nucleotides, one of which was independently obtained by enzymatic phosphorylation with the wheat shoot phosphotransferase system. The behaviour of these nucleotides has been examined in several enzyme systems. In particular, the seco 3':5'- cyclic phosphates are resistant to beef heart cyclic nucleotide phosphodiesterase, but are slowly hydrolyzed to the monophosphates by higher plant cyclic nucleotide phosphodiesterase.