As a result of studies with glycopeptides isolated from hen's-egg albumin, it was suggested that the bond linking carbohydrate to this protein was that of an N-(P-aspartyl)glycosylamine (Johansen, Mar

Vol. 87 DOCOSAHEXAENOIC ACID IN OX RETINA 265 of the cyclohexyl esters of the acids produced showed cyclohexyl propionate, dicyclohexyl malonate and dicyclohexyl succinate to be present, the last two in a 5-2: 1 molar ratio (calculated from the areas under the peaks on the chromatogram). Six structures are therefore possible for the docosahexaenoic acid: the double bonds could be at positions 4,7,

N-(L-P-Aspartyl)-P-D-ghcopyranosylamine (Ia) and -D-glucosamine (I Ia) have been prepared as models of corresponding derivatives possibly present in egg albumin. a-Benzyl benzyloxycarbonyl-L-aspartate (V) was made to react with tetra-O-acetyl-P-D-glucopyranosylamine (111) and -P-D-glucosamine (IV) in the presence of dicyclohexylcarbodi-imide, yielding 2,3,4,6-tetra-O-acety1-N-(a-benzyl benzyloxycarbonyl-L-P-aspartyl) -P-D-glucopyranosylamine (Ib) and 1,3,4,6-tetra-O-acetyl-N-(a-benzyl benzyloxycarbonyl-L-P-aspartyl)-P-D-ghcosamine (IIb), respectively. Removal of protecting groups afforded the glucopeptides (Ia) and (IIa). The stability of the N-acyl-glucosylamine linkage in (Ia) and of the amide linkage in (IIa) was studied.

No abstract

Eight rabbits and 24 guinea-pigs were exposed to a silica dust cloud of about 40,000 pp./ml.(03-30 ,L) and killed at four-weekly intervals up to 30 weeks. The guinea-pigs showed an increase of lung lipid and phospholipid; the latter showed a parallel with the rising collagen level estimated chemically. In the rabbits there was no increase of either lipid or phospholipid. The likely explanation is that the silica did not reach the lungs in sufficient quantity.