PADGEM (GMP140) is a component of Weibel-Palade bodies of human endothelial cells

PADGEM protein (PADGEM), also known as GMP140, is a platelet alpha- granule membrane protein that is translocated to the external membrane after platelet activation. Although the biosynthesis of this protein was originally thought to be confined to megakaryocytes, the synthesis of PADGEM in endothelial cells was recently demonstrated (McEver et al: Blood 70:1974a, 1987). We now describe the subcellular localization of this protein in endothelial cells. Immunofluorescence staining of permeabilized human umbilical vein endothelial cells with KC4, a well characterized monoclonal antibody to PADGEM, showed positively stained elongated structures similar in distribution and shape to Weibel-Palade bodies. Their identity as Weibel-Palade bodies was confirmed by double label immunofluorescence using KC4 and a polyclonal antiserum to von Willebrand factor (vWf), a protein known to be specifically stored in these organelles. All Weibel-Palade bodies were found to contain PADGEM. In contrast to strong perinuclear staining produced with anti- vWf antibodies, no significant perinuclear staining was obtained with KC4, indicating that relatively little PADGEM is present in the endoplasmic reticulum and in the Golgi apparatus. In endothelial cells treated with secretagogues that stimulate vWf release the elongated structures positive for PADGEM disappeared, further identifying these structures as Weibel-Palade bodies. This observation extends the parallels between Weibel-Palade bodies and alpha-granules and suggests a possible functional association between vWf and PADGEM.     

BUILDING THE FOUNDATION OF EXCELLENCE IN HEART FAILURE NURSING

This column contains the presidential address presented during the Third Annual Meeting of the American Association of Heart Failure Nurses on June 28, 2007, in San Diego, California, titled "Building the Foundation of Excellence in Heart Failure Nursing."     

Prognostic importance of collateral flow and residual coronary stenosis of the myocardial infarct artery after anterior wall Q-wave acute myocardial infarction

Residual high-grade coronary stenosis and collateral flow are frequent findings in the chronic phase after a Q-wave acute myocardial infarction (AMI). The prognostic importance of a residual stenosis of the infarct artery and of collateral flow to the infarct area was analyzed in a group of 102 young patients (mean age 35 years, range 22 to 39) who had survived an anterior wall Q-wave AMI. Patients whose only significant lesion (greater than 50% luminal diameter reduction) was in the proximal portion of the left anterior descending artery were enrolled in the study. A 50 to 74% diameter stenosis was present in 33 of 102 patients (32%), 43 (42%) had a 75 to 99% stenosis and 26% had a total occlusion of the infarct vessel. Collateral vessels, which were evaluated by a scoring system, were present in 52 of 102 patients (51%). Four percent had only faint (score 1), 17 of 102 patients (17%) had moderate and 32 patients (31%) had good collateral flow (score greater than 4). The 8-year cumulative mortality was 15.2%--an eightfold increase compared with the age-matched general population. No patient with less than 75% stenosis died during follow-up, whereas the cumulative 8-year mortality was 23 and 17% in patients with a 75 to 99% stenosis or total occlusion, respectively (p less than 0.01). Patients with at least moderate collateral flow had a mortality rate of 21%, versus 8% for patients without or with faint collateral flow (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term changes in the magnetic resonance image after chemonucleolysis

Summary After treatment of a symptomatic herniated disc with chymopapain, 14 patients were re-examined by magnetic resonance imaging (MRI) at a mean follow-up of 72 months. Well-defined MRI findings before chemonucleolysis were compared with those after the procedure by an independent observer. Five MRI parameters were assessed. No significant change was noted in the signal intensity of the affected disc, the extent of osteochondrosis and endplate reaction of the affected segment. The height of the affected disc as well as the size of the disc herniation were reduced significantly. The loss of the height is seen as a direct result of chymopapain activity, whereas the alteration of the size of the herniation seems to depend on the natural history of a disc herniation and is probably not a simple result of the treatment.