A new experimental approach was used to determine whether a eucaloric, low fat, high carbohydrate diet increases fatty acid synthesis. Normal volunteers consumed low fat liquid formula diets (10% of calories as fat and 75% as glucose polymers, n ϭ 7) or high fat diets (40% of calories as fat and 45% as glucose polymers, n ϭ 3) for 25 d.

Alcohol intake increases HDL-C in a dose-dependent fashion, associated with and possibly caused by an increase in the TR of HDL apolipoproteins apoA-I and -II.

SummaryWe have createdJ chain knockout mice to define the physiologic role of theJ chain in immunoglobulin synthesis and transport. The J chain is covalently associated with pentameric immunoglobulin (Ig) M and dimeric IgA and is also expressed in most IgG-secreting cells . J chain-deficient mice have normal serum IgM and IgG levels but markedly elevated serum IgA. Although polymeric IgA was present in the mutant mice, a larger proportion of their serum IgA was monomeric than was found in wild-type mouse serum. Bile and fecal IgA levels were decreased in J chain-deficient mice compared with wild-type mice, suggesting inefficient transport of J chain-deficient IgA by hepatic polymeric immunoglobulin receptors (pIgR) . The pIgR-mediated transport of serum-derived IgA from wild-type and mutant mice was assessed in MadinDarby canine kidney (MDCK) cells transfected with the pIgR. These studies revealed selective transport by pIgR-expressing MDCK cells ofwild-type IgA but not j chain-deficient IgA. We conclude that although the J chain is not required for IgA dimerization, it does affect the efficiency of polymerization or have a role in maintaining IgA dimer stability . Furthermore, the J chain is essential for efficient hepatic pIgR transport of IgA .