Gregorio Chejfec

Experimental Study of Determinants of Aneurysmal Expansion of the Abdominal Aorta

The natural history and the factors determining the expansion of aneurysms have not been elucidated. To study the respective roles of elastolysis, collagenolysis, inflammatory cells, and hypertension in the pathogenesis of aneurysms, two previously described in vivo experimental models were used. An isolated segment of the abdominal aorta was infused with 15 units of pancreatic elastase. The maximal diameter of the aorta was measured before and after infusion and the isolated aorta was excised for classic histologic and immunohistologic studies. Twelve hours after the infusion of elastase the mean diameter of the aorta increased by 30%. The aorta had a cylindric form and only collagen fibers remained. Two and a half days after the infusion the aorta was spherical in shape and the diameter increased by 300% (3.09±0.08 mm) (p<0.05).The entire aortic wall was invested by inflammatory cells. Six days after infusion the diameter increased by 421% (4.38±0.03 mm) (p<0.05),and immunohistochemical staining showed numerous T lymphocytes and macrophages. Between 6 and 12 days, after perfusion inflammation decreased, the final diameter was 4.23±0.14 mm (not significant). Sixteen rats had thioglycollate and plasmin infusion, which are nonspecific activators of inflammation. Nine days after infusion the diameter of the aorta had increased by 288%; the elastic fibers of the media were fragmented and rare and the entire aortic wall was invaded by inflammatory cells, predominantly macrophages. The diameter of the aorta increased progressively. Two groups of 17 hypertensive rats (renovascular and spontaneous hypertension) received an aortic infusion of 15 units of pancreatic elastase. Elastolysis overlapped the limits of the infusion and inflammation persisted after 2 weeks. The mean diameter of the aorta (F = 11,p<0.01)and the mean length of the aneurysms (F = 11.2,p< 0.001)were significantly increased. This study demonstrates that elastolysis and especially collagenolysis are determinants of aneurysmal expansion. Inflammation may be a promoting factor in the degradation of the aortic wall. Hypertension increases the hemodynamic stress to the aorta and activates mural inflammation.

Cystic glucagonoma: a rare variant of an uncommon neuroendocrine pancreas tumor

Glucagon-producing neuroendocrine tumors typically present with a characteristic constellation of symptoms including necrolytic migratory erythema, non-insulin-dependent diabetes, weight loss, anemia, glossifis, and an increased thrombotic tendency. Most ghicagonomas are solid and arise in the body or tail of the pancreas. We report two cases of cystic glucagonoma, one found incidentally in an asymptomatic patient and one in a patient with weight loss and diabetes but no rash. In the first patient, distal pancreatectomy and splenectomy were curative, whereas the second patient continued to exhibit elevated serum glucagon levels and symptoms of glucose intolerance in the absence of demonstrable metastases. Cystic glucagonoma is a unique variant of classic glucagonoma and should be considered in the differential diagnosis of cystic pancreatic neoplasms.

Immunocytochemical Localization of Keratin in Normal, Dysplastic and Neoplastic Cervical Epithelium

The PAP immunocytochemical technique utilizing specific keratin antibody was applied to paraffin sections from 36 cervical biopsies. Normal squamous epithelium and condylomas had similar patterns of keratin production with intense staining of intermediate and upper layers, while basal cells remained negative. Dysplasia, carcinoma in situ and infiltrating squamous carcinoma showed uneven distribution of keratin with the least amount seen in the areas with high mitotic rate and anaplasia. All large cell squamous carcinomas demonstrated presence of significant amounts of keratin. Squamous carcinomas of the small cell type were essentially keratin-free.