The use of formvar films on both sides of a section to facilitate the selected surface technique for double immunostaining at the electron microscope level.
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Humans↗
Biomedical subjects
J Moss
Publications and source records attributed to J Moss.
Large doses of vecuronium and plasma histamine concentrations.
The authors studied 20 surgical patients to determine the effect of large doses of vecuronium on plasma histamine concentrations. Patients were unpremedicated and anaesthetized with nitrous oxide and halothane via a mask. Tracheal intubation was performed without the use of muscle relaxants. Fifteen min later and before surgery had begun, vecuronium, in doses of 0.1 and 0.2 mg.kg-1 (n = 10 for each dose), was administered as an IV bolus. Arterial blood samples were obtained prior to and 2, 5, and 10 min after vecuronium administration and analyzed for plasma histamine by a radioenzymatic method. Arterial blood pressure and heart rate were measured continuously. In one patient who received 0.1 mg.kg-1 of vecuronium, plasma histamine concentrations at 2 min were 275 per cent of the control histamine value but fell below control at 10 min. This increase in plasma histamine was not associated with clinically important changes in blood pressure or heart rate. As a group, study patients had no significant changes in plasma histamine concentrations with either dose of vecuronium. In addition, mean plasma histamine values for each sampling interval did not differ between the two patient groups. Mean arterial blood pressure (MAP) decreased significantly at 10 min in patients receiving vecuronium 0.1 mg.kg-1, and at 2 and 10 min in patients receiving 0.2 mg.kg-1 of vecuronium. However, these decreases in MAP were not clinically important. Changes in plasma histamine concentrations did not correlate with corresponding changes in MAP. Heart rate did not change significantly in any patient during the study.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Endothelium-dependent vascular smooth muscle control.
Recent pharmacologic evidence supports the importance of the integrity of the endothelium in modulating vascular reactivity. The endothelial cells produce one or more endothelium derived relaxing factor(s) or EDRF that cause relaxation of vascular smooth muscle cells through production of cyclic guanosine monophosphate (GMP) and subsequent activation of protein kinase. While the molecular pharmacology of vascular relaxation is now well defined and numerous factors have been identified that inhibit or stabilize EDRF, the chemical identity of EDRF still is uncertain. Nitric oxide appears to be one such EDRF. Alterations in vasoreactivity observed during surgical manipulation, trauma, inhalational anesthesia, atherosclerosis, and other disease states can now be explained by their influence on the endothelial cells and EDRF. Further, it is now clear that nitrovasodilators act directly on the vascular smooth muscle cell to produce biological intermediates that mimic the endogenous factors. While anesthesiologists and critical care physicians have traditionally focused on hormonal and nervous system control of vascular reactivity, the effects of various drugs and manipulations on EDRF appear to be of clinical importance. In this manuscript we review the pharmacology of EDRF and of exogenous nitrovasodilators with particular reference to factors that can modulate vasoreactivity.
Endothelium, Vascular↗
Guanine nucleotide-binding proteins that enhance choleragen ADP-ribosyltransferase activity: nucleotide and deduced amino acid sequence of an ADP-ribosylation factor cDNA.
Three (two soluble and one membrane) guanine nucleotide-binding proteins (G proteins) that enhance ADP-ribosylation of the Gs alpha stimulatory subunit of the adenylyl cyclase (EC 4.6.1.1) complex by choleragen have recently been purified from bovine brain. To further define the structure and function of these ADP-ribosylation factors (ARFs), we isolated a cDNA clone (lambda ARF2B) from a bovine retinal library by screening with a mixed heptadecanucleotide probe whose sequence was based on the partial amino acid sequence of one of the soluble ARFs from bovine brain. Comparison of the deduced amino acid sequence of lambda ARF2B with sequences of peptides from the ARF protein (total of 60 amino acids) revealed only two differences. Whether these are cloning artifacts or reflect the existence of more than one ARF protein remains to be determined. Deduced amino acid sequences of ARF, Go alpha (the alpha subunit of a G protein that may be involved in regulation of ion fluxes), and c-Ha-ras gene product p21 show similarities in regions believed to be involved in guanine nucleotide binding and GTP hydrolysis. ARF apparently lacks a site analogous to that ADP-ribosylated by choleragen in G-protein alpha subunits. Although both the ARF proteins and the alpha subunits bind guanine nucleotides and serve as choleragen substrates, they must interact with the toxin A1 peptide in different ways. In addition to serving as an ADP-ribose acceptor, ARF interacts with the toxin in a manner that modifies its catalytic properties.
ADP-Ribosylation Factors↗
Vecuronium inhibits histamine N-methyltransferase.
Although there have been clinical reports of significant hypotension and flushing associated with the use of vecuronium, it produces minimal cardiovascular effects in the vast majority of patients. In addition, there is no evidence that vecuronium stimulates the release of histamine. The authors performed in vitro kinetic studies to determine the effect of vecuronium on histamine N-methyltransferase (HNMT), the primary catabolic enzyme for histamine in humans. They also examined plasma from patients who had received vecuronium (0.1 or 0.2 mg/kg) to determine whether clinically used concentrations of the drug could inhibit HNMT. It was determined that vecuronium is a strong inhibitor of HNMT; apparent Ki = 1 microM. The inhibition is competitive with respect to methyl-donor and noncompetitive with respect to histamine. Vecuronium, in doses greater than or equal to 0.1 mg/kg, may delay the metabolism of histamine by HNMT in vitro.
Histamine N-Methyltransferase↗
A simple technique for in situ embedding of monolayer cultures in Lowicryl K4M.
A number of difficulties are encountered in embedding monolayer cultures at low temperature in Lowicryl K4M resin. In this paper we present a simple procedure using Lab-Tek Flaskettes in which fixation, processing and embedding of monolayer cultures can readily be achieved.
Acrylic Resins↗
Electron microscopy of undecalcified human bone.
An alternative approach for the electron microscopical examination of undecalcified human bone was investigated. The method required bone to be chilled to -70 degrees C, sectioned at 10 microns in a special bone cryostat, and these sections to be fixed and embedded for ultrathin sectioning. Good preservation of bone cells was seen. The advantages of this method are that it allows numerous particular regions of the 10 microns thick sections to be selected under normal light microscopy, and these regions to be then selected for electron microscopy. The 10 microns sections allow for excellent penetration of the fixative and thus better preservation of the tissue is more likely.
Bone and Bones↗
Atrial natriuretic factor reduces cyclic adenosine monophosphate content of human fibroblasts by enhancing phosphodiesterase activity.
Radioligand binding studies disclosed one class of high affinity atrial natriuretic factor (ANF) receptors on human fibroblast membranes (Kd = 66 pM; maximum number of binding sites [Bmax] = 7,000 sites/cell). ANF increased cellular cyclic guanosine monophosphate (cGMP) content and suppressed isoproterenol- and PGE1-elevated, but not basal, cAMP content. Pertussis toxin pretreatment, which maximally ADP-ribosylated Gi, the guanine nucleotide-binding protein that couples inhibitory receptors to adenylate cyclase and blocks receptor-mediated inhibition of adenylate cyclase, did not interfere with ANF suppression of isoproterenol- or PGE1-elevated cellular cAMP content. Preliminary incubation of fibroblasts with 8-bromo cGMP or phosphodiesterase inhibitors, including 3-isobutyl-1-methylxanthine, Ro 20-1724, and cilostamide, however, prevented the ANF suppression of cAMP. MB 22948, an inhibitor that is partially selective for cGMP phosphodiesterase, did not block the effect of ANF. We conclude that in these cells, unlike other systems, ANF reduces cAMP content by activating a phosphodiesterase rather than by inhibiting adenylate cyclase.
1-Methyl-3-isobutylxanthine↗
Laryngeal complication of warfarin sodium therapy.
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Aged↗
The impersonalization of radiological technology.
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Canada↗
The nursing shortage and the hospital governing board.
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Governing Board↗
Mechanism of enhanced sensitivity to bradykinin in pertussis toxin-treated fibroblasts: toxin increases bradykinin-stimulated prostaglandin formation.
Exposure of animals to pertussis toxin results in increased sensitivity to agents such as bradykinin. To elucidate the molecular mechanisms underlying the effects of toxin, bradykinin responsiveness was examined in control and intoxicated human fibroblasts. Exposure of fibroblasts to toxin resulted in a loss of inhibitory agonist action on adenylate cyclase, elevation of basal cAMP, and ADP-ribosylation of a 41-kDa protein, which was identified as Gi alpha, a component of adenylate cyclase, by its pattern of immuno-cross-reactivity with a family of antibodies to guanyl nucleotide-binding proteins, which are pertussis toxin substrates, and by the presence of an mRNA species with characteristics of a form of Gi alpha. Bradykinin increased prostaglandin accumulation to a greater extent in toxin-treated than in control fibroblasts. Agents such as cholera toxin, which elevated cAMP, also increased bradykinin-induced prostaglandin production. These data are consistent with the hypothesis that the enhanced sensitivity to bradykinin after pertussis toxin treatment results from modification of Gi alpha and increased cAMP, leading to enhanced formation of prostaglandins in response to bradykinin.
Adenosine Diphosphate Ribose↗
Interferon-induced glomerular basement membrane and endothelial cell lesions in mice. An immunogold ultrastructural study of basement membrane components.
Newborn Swiss mice were injected daily for the first week of life with mouse interferon alpha/beta. This treatment resulted in a delay in the maturation of the kidney and the development of glomerular abnormalities. The width of the glomerular basement membrane (GBM) was increased up to tenfold and was characterized by a marked thickening of the endothelial aspect of the GBM. The endothelial cells lining the capillary loops were also abnormal with many dilated regions of the rough endoplasmic reticulum that contained amorphous electron-opaque material. Immunogold studies showed that type IV collagen and laminin/entactin were distributed throughout the thickened GBM, and also within the dilated rough endoplasmic reticulum of the endothelial cells. These results show that the interferon-induced lesion within the glomerulus is associated with an accumulation of normal GBM components and that endothelial cells are involved in this pathologic process.
Animals↗
Signal transduction by guanine nucleotide-binding proteins: possible molecular basis for multiple forms of Go alpha mRNA.
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Animals↗
Ultrastructural studies of a lysosomal enzyme during lymphocyte activation.
A post-embedding immunogold technique has been used for the ultrastructural localization of a lysosomal enzyme, beta-glucuronidase, in resting and activated T- and B-lymphocytes. The results presented here show that mitogen-induced stimulation of T- and B-cells was associated with an increase in the amount of enzyme in the Golgi complex and rough endoplasmic reticulum, organelles which were rarely present in the resting lymphocytes.
Animals↗
Inhibition of the GTPase activity of transducin by an NAD+:arginine ADP-ribosyltransferase from turkey erythrocytes.
The bacterial toxins, choleragen and pertussis toxin, inhibit the light-stimulated GTPase activity of bovine retinal rod outer segments by catalysing the ADP-ribosylation of the alpha-subunit (T alpha) of transducin [Abood, Hurley, Pappone, Bourne & Stryer (1982) J. Biol. Chem. 257, 10540-10543; Van Dop, Yamanaka, Steinberg, Sekura, Manclark, Stryer & Bourne (1984) J. Biol. Chem. 259, 23-26]. Incubation of retinal rod outer segments with NAD+ and a purified NAD+:arginine ADP-ribosyltransferase from turkey erythrocytes resulted in approx. 60% inhibition of GTPase activity. Inhibition was dependent on both enzyme and NAD+, and was potentiated by the non-hydrolysable GTP analogues guanosine 5'-[beta gamma-imido]triphosphate (p[NH]ppG) and guanosine 5'-[beta gamma-methylene]triphosphate (p[CH2]ppG). The transferase ADP-ribosylated both the T alpha and T beta subunits of purified transducin. T alpha (39 kDa), after ADP-ribosylation, migrated as two distinct peptides with molecular masses of 42 kDa and 46 kDa on SDS/polyacrylamide-gel electrophoresis. T beta (36 kDa), after ADP-ribosylation, migrated as a 38 kDa peptide. With purified transducin subunits, it was observed that the GTPase activity of ADP-ribosylated T alpha, reconstituted with unmodified T beta gamma and photolysed rhodopsin, was decreased by 80%; conversely, reconstitution of T alpha with ADP-ribosyl-T beta gamma resulted in only a 19% inhibition of GTPase. Thus ADP-ribosylation of T alpha, the transducin subunit that contains the guanine nucleotide-binding site, has more dramatic effects on GTPase activity than does modification of the critical 'helper subunits' T beta gamma. To elucidate the mechanism of GTPase inhibition by transferase, we studied the effect of ADP-ribosylation on p[NH]pp[3H]G binding to transducin. It was shown previously that modification of transducin by choleragen, which like transferase ADP-ribosylates arginine residues, did not affect guanine nucleotide binding. ADP-ribosylation by the transferase, however, decreased p[NH]pp[3H]G binding, consistent with the hypothesis that choleragen and transferase inhibit GTPase by different mechanisms.
ADP Ribose Transferases↗
Hydroxylamine-stable covalent linkage of myristic acid in G0 alpha, a guanine nucleotide-binding protein of bovine brain.
G0 alpha, a guanine nucleotide-binding protein with a strong homology to the G1 alpha and Gs alpha regulatory proteins of adenylate cyclase, is shown to contain myristic acid. The attachment of myristate to the protein is stable to hydroxylamine treatment, and since the amino-terminal sequence of G0 alpha is typical of proteins with amino-terminal myristate, the inference is strong that G0 alpha is also myristylated at its amino-terminal glycine.
Amino Acid Sequence↗