The effect of different concentrations (0.06, 0.6 and 6.0 mmol/L) of ascorbic acid on neutrophil-endothelial interaction was studied using an in vitro model of human umbilical cord vein endothelial cells and human neutrophils. The aim of the study was to determine changes in chemiluminescence response of neutrophils during adherence to endothelial cells. Because adherence of neutrophils to endothelial cells is an essential component in inflammatory processes leading to endothelial cell injury, the influence of ascorbic acid on adherence and endothelial cell injury have been investigated. Production of oxygen-derived metabolites, measured by chemiluminescence response of neutrophils, decreased significantly in the presence of 6 mmol/L ascorbic acid during coincubation of neutrophils and endothelial cells (p < 0.025). The adherence of neutrophils to endothelial cells was significantly decreased at a concentration of 6 mmol/L (p < 0.0005). The inhibition of neutrophil adherence to endothelial cells was correlated with a diminished neutrophil-mediated endothelial cell injury during incubation with 6 mmol/L ascorbic acid (p < 0.0005). The present results indicate that ascorbic acid might exert a protective effect on neutrophil-mediated endothelial cell injury by decreasing adherence of neutrophils to endothelial cells and by scavenging reactive oxygen metabolites. Moreover, the current investigation points to probable protective effect of ascorbic acid on oxidant-mediated cell damage in diseases (e.g., Adult Respiratory Distress Syndrome).

Ascorbic Acid↗

PubMedDate not supplied

Detection of 6-acetylmorphine in vitreous humor and cerebrospinal fluid--comparison with urinary analysis for proving heroin administration in opiate fatalities.

The concentrations of morphine and 6-acetylmorphine (6-AM) in urine, cerebrospinal fluid (CSF), and vitreous humor (VH) and the morphine concentrations in blood were determined by gas chromatography-mass spectrometry for 29 fatalities after abuse of heroin either alone or in combination with alcohol and other drugs. 6-AM was found above a quantitation limit of 1 ng/mL in urine in 89% of the cases, in CSF in 68% of the cases, and in VH in 75% of the cases. The 6-AM concentrations in CSF (mean, 10 ng/mL) and VH (mean, 17 ng/mL) were in general much smaller than in urine (mean, 170 ng/mL); therefore, the different pharmacokinetic behavior of the fluids is discussed. There is no uniformity between the three fluids with respect to the presence or absence of 6-AM. Therefore, CSF or VH may be used as complementary or alternative materials to urine in order to prove heroin uptake in opiate fatalities.

Adult↗

PubMedDate not supplied

ATP-dependent proton transport into vesicles of microsomal membranes of Zea mays coleoptiles.

ATP-dependent proton pumps were found in the vesicles of microsomal membrane fractions of maize coleoptiles. Two membrane fractions isolated by density gradient centrifugation were identified by the aid of marker enzymes and electron microscopic analysis. Membrane fraction A largely consisted of vesicles of smooth ER and of the Golgi complex, fraction B predominantly of vesicles of plasmalemma and rough ER. The pH-indicator, neutral red, was used to measure changes in pH in the vesicles after ATP addition. Due to the binding of protonated neutral red molecules (NRH+) to negative charges of the energized membrane, a strong metachromasy of NRH+-absorption can be observed. Therefore, in order to accurately measure delta pH a pH-dependent change in absorption of neutral red covering the whole NR-spectrum was set up as difference spectra. The commonly employed method of measuring delta A of neutral red at just one wavelength (525 nm) leads to entirely incorrect results. It could be demonstrated that the ATP-dependent translocation of H+-ions into the interior of the vesicles was most efficient at pH 7. Acidification, which reaches its maximum 10--15 min after ATP addition, can be reverted by adding CCCP. An ATP-dependent proton-translocation into the vesicles of fraction B was also observed, however, the proton translocation is less than that found in fraction A in relation to the amount or protein found in each. The membrane fraction A displays a strong oxidation of NADH subsequently followed by an alkalization of the medium. This process cannot be reverted by adding CCCP. NADH oxidation at membranes of fraction A is consequently not an integral part of a redox-pump. A possible significance of the ATP-dependent proton pump in membranes of the ER and Golgi fraction of coleoptiles is discussed in connection with auxin induced elongation growth.

Adenosine Triphosphatases↗

PubMedDate not supplied

Biological activities of sesquiterpene lactones from Helianthus annuus: antimicrobial and cytotoxic properties; influence on DNA, RNA, and protein synthesis.

Sesquiterpene lactones, produced in light and capable of inhibiting auxin-induced elongation growth of coleoptile and hypocotyl segments, were isolated from young leaves of Helianthus annuus (Spring and Hager, Planta in press, 1982). These compounds have an antibiotic effect on gram-negative and gram-positive bacteria as well as on some fungi. The minimal inhibiting concentration (MIC) of compound II (15-hydroxy-3-dehydrodesoxyfruticin, Fig. 1), for example, is 15 micrograms/ml for Bacillus brevis, and 95 micrograms/ml for the fungus Eremothecium ashbyi. In addition, cytotoxic effects on mouse myeloma cells (NS-1) were also shown. Compound II causes a 50% inhibition of cell proliferation (ED50) at a concentration of 170 nM, compound I (niveusin C, Fig. 1) at 220 nM. The LD50-values were 0.15 micrograms II/ml and 1.24 micrograms I/ml, respectively. By measuring 14C-labelled thymidine, uridine and leucine incorporation into murine cells of the ascitic form of Ehrlich carcinoma (EAC) it could be shown that compounds I and II inhibit DNA and RNA synthesis, but do not affect the translation processes involved in protein synthesis. Furthermore, it could be shown that the exocyclic methylene group in the molecules of I and II plays an important role in triggering the described inhibitory effects.

Animals↗