Arylamine N-acetyltransferase 2 expression in the developing heart.

Murine arylamine N-acetyltransferase 2 (NAT2) is expressed in the developing heart and in the neural tube at the time of closure. Classically described as a xenobiotic metabolizing enzyme, there is increasing evidence for a distinct biological role for murine NAT2. We have characterized the expression of arylamine N-acetyltransferase 2 during cardiogenesis, mapping its expression in vivo, using a lacZ insertion deletion, and also in vitro, by measuring NAT2 enzyme activity. These findings show that cardiac Nat2 expression is both temporally and spatially regulated during development. In neonatal mice, cardiac Nat2 expression is most extensive in the central fibrous body and is evident in the atrioventricular valves and the valves of the great vessels. Whereas Nat2 expression is not detected in ventricular myocardial cells, Nat2 is strongly expressed in scattered cells in the region of the sinus node, the epicardium of the right atrial appendage, and in the pulmonary artery. Expression of active NAT2 protein is maximal when the developing heart attains the adult circulation pattern and moves from metabolizing glucose to fatty acids. NAT2 acetylating activity in cardiac tissue from Nat2(-/-) and Nat2(+/-) mice indicates a lack of compensating acetylating activity either from other acetylating enzymes or by NAT2 encoded by the wild-type Nat2 allele in Nat2(+/-) heterozygotes. The temporal and spatial control of murine Nat2 expression points to an endogenous role distinct from xenobiotic metabolism and indicates that Nat2 expression may be useful as a marker in cardiac development.     

Increased secretion of type beta transforming growth factor accompanies viral transformation of cells.

Cells transformed by Harvey or Moloney sarcoma virus secrete at least 40 times as much type beta transforming growth factor as their respective untransformed control cells. The transformed cells bind only 20 to 50% as much type beta transforming growth factor as the control cells, suggesting that transformation causes down-regulation of the type beta transforming growth factor receptor.     

Feeding responses of adult seven-spotted ladybirds,Coccinella septempunctata (Coleoptera,Coccinellidae), to insecticide contaminated prey in laboratory arenas

The behavioural responses previously reported from Coccinella septempunctata to the organophosphate, dimethoate, have implications for the effective development of integrated pest management (IPM) strategies. Through a series of simple tests, coccinellids’ consumption rates were measured from live pesticide-resistant aphids, treated with five insecticides from three chemical classes: carbamates, organophosphates and pyrethroids. This study quantifies for the first time the doses of ingested insecticide to which C. septempunctata responds, and demonstrates that a number of insecticides can cause C. septempunctata to change its feeding behaviour. Females were confirmed to eat more than males, and responses to insecticides were observed more frequently in females. Aphid consumption was reduced most in the pyrethroid treatment groups, but choice tests found no preference for either treated or untreated prey in any group. The results are discussed in terms of the mechanism by which coccinellids detect insecticides, and the consequences for IPM.     

Diagnosis of the rare solid and papillary epithelial neoplasm of the pancreas by fine needle aspiration cytology. Light and electron microscopic study of a case

A case of the rare solid and cystic papillary tumor of the pancreas in a young woman is described. The diagnosis was made by fine needle aspiration cytology, with electron microscopic examination of the needle washings. The preoperative cytologic diagnosis enabled appropriate surgical treatment to be planned and carried out without undue delay. It is important to distinguish this rare tumor from other pancreatic tumors with similar cytohistologic features since, if diagnosed correctly and managed surgically, this neoplasm is associated with a good prognosis.