Polyclonal antibody-mediated mitotic inhibition in Chinese hamster ovary cells.

The nucleus of a mammalian cell undergoes profound reorganization when the cell enters mitosis and a number of proteins involved at various levels of the cell cycle have been characterized. The presence of mitotic-specific proteins has been reported and their roles are important in understanding the mechanics of cell division. The ability of antibodies to recognize mitotic protein antigens and further inhibit mitosis is potentially valuable in their role as therapeutic and diagnostic agents in cancer therapy. In this study, we have aimed to analyze proteins isolated from mitotic cells of Chinese hamster ovary (CHO) cells and their significant role in inhibiting mitosis. The proteins extracted from mitotic cells were processed and antibodies produced. It was observed that the secondary response that yielded an antiserum of 1:8 titer was predominantly IgG. The antiserum was effective in inhibiting mitosis in CHO cells in culture in a dose-dependent manner. Although inhibition of mitosis was apparent by cell proliferation studies, there was no apparent effect of the antiserum on other cell morphology and culture characteristics. The unique molecular structure of the antibody by which it bivalently binds to a broad array of antigenic epitopes serves as the foundation of its utility. These antibodies, being polyclonal in nature, are targeted against a whole range of proteins; and their multiple epitopes involved in process of cell division might hence mediate recognition or inhibition of function of such proteins in a wholesome manner and thus accomplish inhibition of mitotic progression.

Morphologic basis for loss of regulated insulin secretion by isolated rat pancreatic islets.

Laboratories engaged in secretory studies of rat pancreatic islets often encounter high baseline insulin secretion with poor secretory response to secretagogues, such as glucose. The specific morphologic abnormalities that accompany this unregulated release have not been described. We isolated islets comparing two approaches. Both used stationary digestion with collagenase. In method I, we distended the biliary duct extracorporeally with collagenase and minced the pancreas after a 28 min digestion (37 degrees C). In method II, we distended the pancreas intracorporeally and digested for 40 min without mincing. Both methods utilized a similar collagenase concentration (2 micrograms/ml in Hank's balanced salt solution (HBSS). Both methods yielded over 300 islets/rat. Islets from both methods appeared intact, when viewed under the dissecting microscope. We found that adequate secretion from incubated islets was evoked with method I, i.e., low basal insulin levels at low glucose (3.3 mM), tripling at 11.0 mM glucose, and nearly quadrupling in response to higher glucose (16.7 mM). In contrast, method II was characterized by high basal levels without response to higher glucose. Ultramicroscopic examination of islet B cells in method I revealed normal cytological features, while B cells in method II showed marked degranulation, profiles of swollen endoplasmic reticulum, and swollen mitochondria. Morphometric analysis of B cells confirmed quantitatively a decrease in secretory granule density and mitochondrial enlargement in method II compared to method I. Anatomic changes, largely confined to the B cells of islets may account for functional alterations of responses. Defects cannot be predicted from gross appearance of islets.

Pericardial complications of cardiac surgery: emphasis on the diagnostic role of echocardiography.

Pericardial effusions are common following cardiac surgery; uncommonly they are large in size and may cause tamponade, either in the early or late postoperative period. Such effusions causing tamponade may be circumcardiac, but are frequently loculated, in which case one or more cardiac chambers is selectively compressed. Fortunately, echocardiography is capable of imaging not only the presence, location, and size of the pericardial effusion, but also indicating the presence of tamponade. Constrictive pericarditis resulting from cardiac surgery is being recognized with increasing frequency and has been associated with various echocardiographic abnormalities. This review also discusses certain other pericardial complications of cardiac surgery including supraventricular arrhythmias, chylopericardium, and posttransplant problems.

Large pericardial effusion after cardiac surgery: role of echocardiography in diagnosis and management.

We performed M-mode and two-dimensional (2-D) echocardiograms prospectively in 140 patients an average of eight days after open heart surgery. Large pericardial effusions occurred in 13 patients; three had complete circumcardiac pericardial effusion, four had local anterior adhesions, five had extensive anterior adhesions (posterior loculated effusion), and one had a large loculated pericardial effusion contiguous to the right atrium. In five patients with tamponade, the effusion was drained, with immediate reversal of symptoms and signs of tamponade. In the other eight patients, who had no deterioration in cardiovascular status, the effusion was not drained; instead, these patients were treated medically with indomethacin and observed with serial echocardiograms, and the effusions eventually disappeared. The most consistent echocardiographic differences between the five patients with and the eight patients without tamponade were that patients with tamponade had larger posterior pericardial effusions, more severe left atrial compression, and more indentation of the right atrial wall. Echocardiography plays an essential role in diagnosis and management of large pericardial effusions after open heart surgery. Patients with large pericardial effusions who are clinically stable need only medical management, including serial echocardiograms, but drainage is indicated if the cardiovascular or respiratory status worsens. Certain echocardiographic findings indicate a high probability of tamponade.

Cardiovascular ochronosis.

A 64-year-old man with alkaptonuric ochronosis required aortic valve replacement for severe aortic stenosis and single-vessel aortocoronary artery bypass grafting for a subtotally occluded obtuse marginal branch of the circumflex coronary artery. Operative findings included ochronosis of a partly calcified aortic valve and the aortic intima. The aortic valve and a punch biopsy specimen of the ascending aorta were removed at surgery and were studied with transmission electron microscopy and light microscopy. The ultrastructural studies of the aortic valve revealed intracellular and extracellular deposits of ochronotic pigment. A portion of the extracellular ochronotic pigment represented degenerated cells. Large deposits of extracellular ochronotic pigment were associated with areas of valvular calcification. Electron microscopic study of the aorta disclosed ochronotic pigment in macrophages and smooth-muscle cells. Aggregates of extracellular ochronotic pigment in the intima and media appeared to be in locations of necrotic cells. Light microscopy also showed intracellular and extracellular deposits of ochronotic pigment. Our study suggests that extensive extracellular deposits of ochronotic pigment in the aortic valve may serve as a stimulus for dystrophic calcification. This may play a role in the development of aortic valve calcification and aortic stenosis associated with alkaptonuric ochronosis. To our knowledge, this is the first ultrastructural study of the aortic valve and aorta in alkaptonuric ochronosis.