Desacetylcephalothin lactone was rapidly hydrolyzed to desacetylcephalothin in 10-20% yield in phosphate and borate buffers (pH 6-9, 100°), in borate and carbonate buffers (pH 9-10.8, 25°), and in 0.01 N KOH (25°). In addition, other uncharacterized products were formed. The dosacetylcephalothin formed was isolated as its cephalothin Me ester after esterification and acetylation. These findings establish the final link in the total synthesis of cephalosporins by the lactone route.
Bovine Growth Hormone (BGH) or Bovine Somatotropin (BST) is a genetically engineered protein hormone either identical or similar to the natural bovine pituitary product. Its primary function is to increase milk production dairy lactating cattle. Therefore, BST is a protein hormone that increases milk production in cows between 10 and 15% (Coghlan, 1994a; Eppard ., 1985; Hileman, 1993a; Hileman, 1994; Hoagland ., 1997; Londono ., 1997; Potter, 1994; Hileman, 1993b). An increase in milk yield typically occurs with 5 days after beginning of treatment. When BST-treated cows were consuming sufficient quantities of nutrients to meet the energy needs for additional milk synthesis, body lipid mobilization did not increase, but lipid synthesis was instead reduced (Sechen ., 1989). BGH increases activity and/or longevity of mammary secretary cells, probably via Insulin-like Growth Factor (IGF)-I produced by the liver and/or the mammary gland (Chilliard ., 1998; FAO/WHO, 1993). IGF-I is a portion of the effects of BST on lactation in dairy cows (Cohick, 1998). The and pasteurized milk could have been levels of IGF-I of 5.6 and 8.2 ng mL-1, respectively. The infant formula could have been only trace amounts of IGF-I of 0.7 ng mL-1. Therefore, IGF-I is not destroyed by the pasteurization process but the heating of milk for the preparation of infant formula denaturizes IGF-I and significantly, reduction (35-48%) levels of IGF-I compared to (FAO/WHO, 1993). BGH is probably stimulating immunological responses of animals and hence increasing the milk cell count (Chilliard ., 1998). It can cause to increase incidence of clinical mastitis in cows (Long, 1993; Hileman, 1993b; Coghlan, 1994b; Judge ., 1997) and sub clinical mastitis in ewes (Brozos ., 1998).This prompted concern that increased use of antibiotics to treat the mastitis might lead to increased residues of such drugs in milk (Long, 1993). Therefore, the risk to human health comes not from BGH residues but from the possibility that residues from the antibiotics used to treat the udder infections could end up in the milk supply (Cohick, 1998). There are many conventions about BST treated in cows. For example, an international meeting of scientists of the United States and Europe has concluded that beef raised with hormonal supplements has no adverse effect on humans and they are safe for cows and humans (Coghlan, 1994; Kaiser, 1995). However, in news of the World Trade Organization has partially accepted European Union (EU) contentions for prohibiting the use of growth-promoting hormones in cattle (Layman, 1998).
Synthesis of cephalosporin compounds, , , , ,
T1 - Chemical conversion of desacetylcephalothin lactone into desacetylcephalothin. The final link in a total synthesis of cephalosporanic acid derivatives