Basolateral apoB secretion decreased. Using the same expression system, fulllength human apoA-IV (376 amino acids); a "pig-like" human apoA-IV, lacking the C-terminal EQQQ repeats (361 amino acids); and a "chicken-like" apoA-IV, further truncated to 343 amino acids, were expressed in IPEC-1 cells. With increasing protein secretion, cells expressing the full-length human apoA-IV displayed a 2-fold increase in TG secretion; in sharp contrast, cells expressing the piglike human apoA-IV displayed a 25-fold increase in TG secretion and a 27-fold increase in lipoprotein diameter. When human apoA-IV was further truncated to yield a chicken-like protein, TG secretion was inhibited. We conclude that overexpression of swine apoA-IV enhances basolateral TG secretion in a dose-dependent manner by increasing the size of secreted lipoproteins. These data suggest that the region in the human apoA-IV protein from residues 344 to 354 is critical to its ability to enhance lipid secretion, perhaps by enabling the packaging of additional core TG into chylomicron particles. The EQQQ-rich region may play an inhibitory or modulatory role in chylomicron packaging in humans.

Paget's disease of the breast nipple and areola complex represents a cutaneous manifestation of an underlying breast malignancy. The typical skin changes characteristic of breast Paget's disease are usually easily distinguished from those found of malignant melanoma. The rare finding of a pigmented cutaneous breast lesion mimicking melanoma presents a diagnostic dilemma. This case presentation describes a pigmented mammary lesion involving the areola that had undergone changes in diameter and pigmentation. The lesion was not associated with nipple drainage, nipple excoriation, dermal ulceration, or a palpable breast mass. The areola lesion was highly suggestive of a dermatologic malignancy such as malignant melanoma. As such, a biopsy was performed with initial findings suggestive of cutaneous melanoma. Upon more detailed analysis of a larger excision specimen, immunohistochemical staining was highly supportive of the diagnosis of breast Paget's disease. A total mastectomy with sentinel lymph node evaluation was performed along with immediate reconstruction. The final pathology revealed a small focus of ductal carcinoma in situ of the breast associated with the areola changes. Histologic and immunohistochemical analysis of a biopsy specimen were paramount in differentiating these two lesions.

No abstract