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."     

Cathodes for fuel cells using proton-conducting Li2SO4–Al2O3 electrolyte

The performances of three widely different cathode materials (Pt, strontium-doped lanthanum manganite (LSM), and NiO) have been compared for use with proton conducting Li₂SO₄–Al₂O₃ composite electrolyte, using H₂S–air and H₂–air fuel cells operating at 600 °C. Surface analysis and electrochemical techniques were used to characterize fresh and used electrode materials. Pt or LSM cathodes each became covered with Li₂SO₄ and Al₂O₃ and, as a consequence, the fuel cells showed poor performance. In contrast, the NiO cathode catalyst did not become covered with Li₂SO₄ and good fuel cell performance was achieved. Exceptionally good current densities of over 100 mA/cm² and power densities of over 30 mW/cm² were obtained for H₂S–air fuel cells having Mo–Ni–S anode catalysts. Slight agglomeration of NiO particles during fuel cell operation had only a minor effect on performance.     

New lipid biochemical aspects in the pathogenesis of a follicular keratinization disorder in acne vulgaris

Follicular hyperkeratinization of the epithelium of the acroinfundibulum of sebaceous follicles is one of the primary events in the pathogenesis of acne vulgaris. Oral treatment with 13-cis-retinoic acid can reduce these hyperkeratoses. In order to determine whether follicular hyperkeratinization is related to disturbances of epidermal follicular lipids, we analyzed the lipids of initial comedones from 10 patients with nodulocystic acne before and after a 6th weeks oral therapy with 13-cis-retinoic acid (0.7 mg/kg body weight). The treatment with retinoid resulted in a significant increase of epidermal lipids (free sterols: +34%; ceramides: +19%, whereas the lipids of sebaceous origin decreased (glycerides: -36%). The mass ratio of free sterols to cholesterol sulfate increased by 86% compared to pre-treatment levels. These findings support the hypothesis that local follicular deficiencies of epidermal lipids due to increased sebum secretion might induce abnormal follicular keratinization.     

Creating a professional practice environment on a shoestring

Did you ever think, “If we just had a little money we could…”? The current health care environment is wrought with financial stressors that can be overwhelming and take up most of our time. Such stress can limit the development of a professional practice environment if you let it. How do you not only survive but thrive in this financial climate?     

Are deficiencies of prostaglandin-E-mediated immunoregulation involved in increased IgE synthesis of atopic mononuclear cells in vitro?

We demonstrate that spontaneous in vitro immunoglobulin E synthesis of atopic peripheral blood mononuclear cells could be suppressed by the addition of 10(-6) M to 10(-5) M prostaglandin E1 (PGE1) or PGE2. Impaired suppressor T lymphocyte maturation and function in atopic individuals are explained by an insufficient transmission of prostaglandin E (PGE) signals during thymic lymphocyte differentiation as well as an impaired ability of the atopic immune system to activate suppressor T cells by PGE-mediated feed back mechanisms. Decreased levels of 6-desaturated PGE-precursor fatty acids in plasma, T lymphocytes, monocytes, adipose tissue and breast milk have been observed in atopic individuals. These insights might offer a novel approach to the prevention of atopic disease by substitution of the atopic pregnant and nursing woman and her newborn infant with long-chain omega-6-fatty acids.     

Dibenzo[a,l]pyrene-induced DNA adduction, tumorigenicity, and Ki-ras oncogene mutations in strain A/J mouse lung

Dibenzo[a,l]pyrene (DB[a,l]P), an environmental polycyclic aromatic hydrocarbon, is the most potent carcinogen ever tested in mouse skin and rat mammary gland. In this study, DB[a,l]P was examined for DNA adduction, tumorigenicity, and induction of Ki-ras oncogene mutations in tumor DNA in strain A/J mouse lung. Groups of mice received a single i.p. injection of 0.3, 1.5, 3.0, or 6.0 mg/kg DB[a,l]P in tricaprylin. Following treatment, DNA adducts were measured at times between 1 and 28 days, while tumors were counted at 250 days and analyzed for the occurrence of point mutations in codons 12 and 61 of the Ki-ras oncogene. DB[a,l]P in strain A/J mouse lung induced six major and four minor DNA adducts. Maximal levels of adduction occurred between 5 and 10 days after injection followed by a gradual decrease. DB[a,l]P-DNA adducts in lung tissue were derived from both anti- and syn-11,12- dihydroxy-13,14-epoxy- 11,12,13,14-tetrahydrodibenzo[a,l]pyrene (DB[a,l]PDE) and both deoxyadenosine (dAdo) and deoxyguanosine (dGuo) residues in DNA as revealed by cochromatography. The major adduct was identified as a product of the reaction of an anti-DB[a,l]PDE with dAdo in DNA. DB[a,l]P induced significant numbers of lung adenomas in a dose- dependent manner, with the highest dose (6.0 mg/kg) yielding 16.1 adenomas/mouse. In tricaprylin-treated control animals, there were 0.67 adenomas/mouse. Based on the administered dose, DB[a,l]P was more active than other environmental carcinogens including benzo[a]pyrene. As a function of time-integrated DNA adduct levels, DB[a,l]P induced lung adenomas with about the same potency as other PAHs, suggesting that the adducts formed by DB[a,l]P are similar in carcinogenic potency to other PAHs in the strain A/J mouse lung model. Analysis of the Ki- ras mutation spectrum in DB[a,l]P-induced lung tumors revealed the predominant mutations to be G-->T transversions in the first base of codon 12, A-->G transitions in the second base of codon 12, and A-->T transversions in the second or third base of codon 61, concordant with the DNA adduct profile.