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PubMedDate not supplied

Evaluation of coal liquids derived from the EDS process in carcinogenesis screening tests.

Four process streams derived from the EDS not equal to direct coal liquefaction process were evaluated in two in vitro assays to screen for carcinogenic potential: the Salmonella/mammalian microsome mutagenicity assay and the Syrian hamster embryo morphologic transformation assay. Three high boiling liquids (two recycle solvents, nominal boiling range 200-425 degrees C; and a fuel oil blend, nominal boiling range 200-538 degrees C) were active in both assays. A hydrotreated naphtha sample (< 200 degrees C) was not active in either. The Salmonella data agreed qualitatively with results of dermal carcinogenesis studies; however, quantitative differences as measured by the estimation of mutagenic potency were apparent. The lack of quantitative agreement may have been related to the fact that the dermal carcinogenic activity of coal-derived synthetic fuels is predominantly associated with neutral polycyclic aromatic hydrocarbons, whereas activity in the Salmonella assay is strongly influenced by the presence of aromatic amines and nitroaromatic compounds. Two modifications of the Salmonella assay--detergent dispersion and hamster S9 activation--were examined. These techniques improved assay performance for some but not all of the coal liquids. The differences in response may have been related to compositional differences in the various liquids.

Alkanes↗

PubMedDate not supplied

Effect of dosing vehicle on the toxicity and metabolism of unsaturated aliphatic nitriles.

The effect of dosing vehicle on toxicity and metabolism of unsaturated aliphatic nitriles was investigated in male Sprague-Dawley rats. Five unsaturated aliphatic nitriles--acrylonitrile, methacrylonitrile, allylnitrile, crotononitrile and fumaronitrile--were prepared in five different dosing vehicles--saline, corn oil, safflower oil, mineral oil, olive oil and Tween-20. Groups of six male rats were given 0.5 LD50 doses of the nitriles by gavage and they were observed for 12 It for cholinomimetic and central nervous system effects. Cyanide and glutathione levels were determined in blood and various organs at 1, 3 and 6 h after nitrile administration and thiocyanate levels were determined at 6 h after nitrile administration. The results indicate that all the vehicles studied potentiated the toxicity of all the nitriles compared to nitriles administered in saline and significantly increased their metabolism to cyanide and thiocyanate and nitrile-induced depletion of glutathione in rats. This behavior of vehicles illustrates the difficulty of identifying suitable vehicles for administration of lipophilic compounds in toxicology studies.

Acrylonitrile↗

PubMed1982

Characteristics of plasma membrane isolated from a mouse T lymphoma line: comparison after nitrogen cavitation, shearing, detergent treatment, and microvesiculation.

Plasma membrane was isolated from the mouse T lymphoma cell line WEHI-22 using four different methods of cell disruption followed by centrifugal fractionation. Disruption by nitrogen cavitation or by shearing with a cell pump produced plasma membrane vesicles of similar buoyant density (1.10 g/ml) and morphological appearance. Few C-type virus particles were present. Cell disruption with 2% Tween-40 produced membrane vesicles of similar morphology but lower density (1.09 g/ml). All of the above preparations resulted in vesicles with aggregated intramembranous particles after freeze fracture. Microvesiculation with sublytic concentration of a lysophosphatidylcholine analog (ET-12-H) (0.0032% w/v) produced small membrane vesicles which could be isolated without differential centrifugation. However, these had a slightly higher density than vesicles prepared by cavitation or shearing and were contaminated by virus particles. Unlike the other preparations, vesicles prepared with ET-12-H had dispersed intramembranous particles. The enzyme gamma-glutamyl transferase was enriched from 20- to 45-fold in the membrane preparations and proved a suitable plasma membrane marker for these cells whose 5'-nucleotidase content is very low.

Animals↗

PubMed1990

Enzyme-linked immunosorbent assay for the epidermal growth factor receptor.

An enzyme-linked immunosorbent assay (ELISA) for the epidermal growth factor (EGF) receptor was developed using three different antibody preparations, one of which is commercially available. Using one of the antisera (986), the assay could detect as few as 200 x 10(6) receptors. This is equal to 0.332 fmol. This sensitivity means that a minimum of 100 A-431 cells (human carcinoma) or 5,000 normal cells are needed to quantitate the number of EGF receptors. Two of the antisera (986 and 451) recognized EGF receptors from placental tissue. EGF receptors from as little as 667 ng of placental membrane protein were detectable. The assay is highly species specific, with the sensitivity for the EGF receptor from different species dependent on the antiserum used. The commercial antibody, 29.1, had especially strong reactivity against pig and dog EGF receptors. An ELISA using this antibody had the capacity to detect the number of EGF receptors in 10 micrograms of liver membrane protein. The assay is sensitive to receptor conformation. The binding of antisera 986 and 451 to 1% sodium dodecyl sulfate (SDS)-denatured receptor was reduced. The binding of antibody 29.1 was impaired by the presence of 1% Triton X-100 but not the same levels of Tween-20 or SDS. In addition to being a sensitive technique for the quantitation of the EGF receptor, this assay is very rapid, taking a total of 4 h. The microtiter dish format also allows hundreds of samples to be assayed at once. By using the appropriate antiserum and standards, the EGF receptor can be quantitated in tissues from humans, dogs, pigs, and mice.

Animals↗

PubMed1976

Rapid breakdown of diphosphoinositide and triphosphoinositide in erythrocyte membranes.

Incubation of rabbit erythrocytes with 32Pi resulted in labeling of membrane diphosphoinositide, triphosphoinositide, and phosphatidic acid. Hypotonic lysis at 37 degress C resulted in an extremely rapid breakdown of the labeled polyphosphoinositides. This breakdown could be retarded by lysis in the presence of EDTA and by lowering the temperature to 0 degrees thus allowing preparation of membranes with minimum breakdown of the labeled lipids. Rapid breakdown of di- and triphosphoinositide in isolated membranes could be initiated by Ca++ or to a lesser extent by Mg++ and prevented by detergents and by heating to 75 degrees C. Assay of radiolabeled lipid was carried out by a method which bypassed prior lipid extraction and which enabled sequential sampling of reactions at 10-second intervals. This method was more convenient than standard procedures and gave yields of di- and triphosphoinositide equivalent to that obtained by the method of Folch.

Animals↗

PubMed1976

Cellular responsiveness to stimulation in vitro: increased responsiveness to colony stimulating factor of bone marrow colony-forming cells treated with surface-active agents and cyclic 3'5' AMP.

Addition of low concentrations (10 ng/ml) of saponin or Tween 80 to stimulated cultures of normal mouse bone marrow in agar increased the number of granulocyte-macrophage colonies which developed. Addition of cyclic AMP or dibutyryl cyclic AMP in low concentration (10(-8) to 10(-10) M) also enhanced colony numbers although concentrations above 10(-5) M were inhibitory. enhancement was found when marrow cells were pre-treated with these agents and cultured in their absence. The agents did not stimulate colony development in the absence of colony-stimulating factor and enhancement of colony number occurred only in cultures containing a concentration of colony-stimulating factor which was sub-optimal in terms of maximum colony development. There was no indication of increased colony-stimulating factor production by treated marrow cells under the experimental conditions used to show colony enhancement. It was concluded that the agents caused an increased responsiveness of colony-forming cells to colony-stimulating factor.

Adenosine Monophosphate↗

PubMed1978

Assay of ribonucleotide reduction in nucleotide-permeable hamster cells.

Ribonucleotide reduction was measured in Chinese hamster ovary cells made permeable to nucleotides by treatment with the detergent Tween-80. When compared to the respective ribonucleotide reductase activity in partially purified cell extracts, CDP and GDP reductase activities in permeabilized cells responded in a similar fashion to dithiothreitol, pH, MgCl2, FeCl3, substrate concentration and the presence of positive or negative allosteric effectors. At low protein concentrations both CDP and GDP reduction with whole cells increased linearly with cell number and was greater than the activity in corresponding cell extracts. Permeabilized cells were used to measure the level of CDP and GDP reductase in a hamster cell line resistant to the cytotoxic effects of hydroxyurea. The hydroxyurea-resistant cell line contained four to ten times more CDP and GDP reductase activity compared to parental or revertant cell lines. The permeabilized cell assay was also used to measure CDP and GDP reductase activities in Chinese hamster ovary cells synchronized by isoleucine starvation. CDP reductase activity was low in G1 arrested cells but increased 10-fold by 16 hours after the readdition of isoleucine to the growth medium. GDP reductase, which is present at much higher levels, is similarly induced after isoleucine addition, but only by 2-fold. The maximum activity of both CDP and GDP reductase occurred from 14 to 16 hours after isoleucine addition, which corresponded to the period of maximum DNA synthesis.

Animals↗

PubMed1991

Genetic characterization of adenovirus transformed cell revertants resistant to methylglyoxal bis(guanylhydrazone): evidence for the involvement of three genetic loci.

Five new independent rat somatic cell mutants resistant to the antileukemic drug methylglyoxal bis(guanylhydrazone) (MGBG) were isolated after mutagen treatment. The mutants were 7- to 10-fold more resistant to MGBG than were the parental wild-type cells. When the MGBG-resistant (MGR) mutants were exposed to the drug in the presence of Tween-80, a nonionic detergent, they became as sensitive (MGS) to MGBG as the wild-type cells, indicating that they were probably permeability mutants. Genetic analysis of hybrids between MGR mutants and wild-type cells showed that MGR and the nontransformed alleles to be recessive to the MGS (wild-type) and transformed phenotype, respectively. Complementation analysis of the seven mutants revealed three functional genetic units or loci responsible not only for the MGR phenotype but also for tumorigenicity as determined in nude mice. Only the MGS hybrids produced tumors in the nude mice, whereas the MGR hybrids and mutants did not. Our results suggest the existence of cellular membrane components that are responsible both for cellular tumorigenicity and resistance to MGBG.

Adenoviridae↗

PubMed2005

Airway gene transfer using cationic emulsion as a mucosal gene carrier.

BACKGROUND: Delivery of genes to airway mucosa would be a very valuable method for gene therapy and vaccination. However, there have been few reports on suitable gene delivery systems for administration. In this study, we use a cationic emulsion system, which is physically stable and facilitates the transfer of genes in the presence of up to 90% serum, as a mucosal gene carrier. METHODS AND RESULTS: Cationic lipid emulsion was formulated with squalene and 1,2-dioleoyl-sn-glycero-3-trimethylammoniumpropane (DOTAP) as major components. Emulsions formed stable complexes with DNA and protected and transferred DNA to target cells against DNase I digestion in the presence of mucosal destabilizers such as heparin sulfate (a polysaccharide of the glycosaminoglycan family in mucosa) and Newfectan (a natural lung extract of bovine) in an in vitro system. In contrast, commercial liposomes and counter liposomes, made with an identical lipid composition of emulsions, failed. After in vivo intranasal instillation, the cationic emulsion showed at least 200 times better transfection activity than the liposomal carriers in both nasal tissue and lung. CONCLUSIONS: These findings show that cationic emulsions can mediate gene transfection into airway epithelium, making it a good choice for transferring therapeutic genes and for genetic vaccination against an pathogenic infection via an airway route.

Carcinoma, Large Cell↗

PubMed1978

Association of normal serum protein antigens with chimpanzee hepatitis B surface antigen particles.

HBsAg/adw was purified from 2.6 liters of pooled plasma from a single chimpanzee carrier by polyethylene glycol (PEG) precipitation followed by isopycnic and rate zonal centrifugation. The different morphological populatilons of HBsAg separated in the final rate zonal centrifugation step were combined into seven pools: two fractions rich in filaments and Dane particles, two pools composed of filaments and 20--28-nm spheres, and three fractions containing mostly 20--28-nm spheres. The purified preparations of HBsAg analyzed for normal serum protein contaminants revealed albumin and traces of IgG. The same samples analyzed after Tween-80 treatment, revealed enhanced quantitites of the previous two contaminants, and in addition, transferrin, traces of alpha2-macroglobulin, IgM, and complement (C3/C3c). The residual contaminants were mostly removed by further purification and fractionation after detergent treatment using zone convection electrofocusing and rate zonal centrifugation. Our findings indicate that conventional purification techniques will not provide preparations of HBsAg free of traces of serum protein contaminants. Many of these are released only by detergent treatments and subsequent purification. It is not yet clear whether detergents release these contaminants from the interior of the particles or from firm association or incorporation within the membranes.

Aged↗

PubMed1979

Cryptic association of e antigen with different morphologic forms of hepatitis B surface antigen.

When highly purified HBsAg particles, separated by rate zonal centrifugation into populations differing in predominant size, were tested for HBeAg, the e1 specificity was detected preferentially in association with particle fractions containing large filaments and Dane particles. These results were obtained both by agar gel diffusion and by radioimmunoassay for e antigen. The e antigen activity present in these fractions was potentiated by prior treatment of particles with Tween 80, suggesting cryptic localization of e1 specificity within or under the outer membrane. The HBeAg released by detergent treatment from a purified preparation composed predominantly of small-particle forms of HBsAg was separated by electrofocusing into a peak of nonparticulate e antigen in the pH range of 5.7--6.0. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed three major polypeptides in this preparation with approximate molecular weights of 25,000, 55,000, and 70,000. Furthermore, two additional peaks of e antigen activity were detected which migrated in association with HBsAg particles at isoelectric points of 4.4 and 5.5--5.6. The major portion of e antigen remained in association with particles after further purification by rate zonal centrifugation.

Animals↗

PubMed1990

The effect of non-ionic surfactants on the SOS-inducing potency of 4-nitroquinoline-1-oxide in Escherichia coli PQ37.

Various non-ionic surfactants affect the SOS-inducing potency (SOSIP) of the model genotoxin, 4-nitroquinoline-1-oxide, in Escherichia coli PQ37 to varying degrees, as measured by an automated version of the SOS chromotest. While there is little effect on the SOSIP value and other test parameters from Tween 20 and 80 and, with some reservation, Triton X305 and Tyloxapol, over the critical micelle concentration range, the SOSIP value increases in the presence of comparable concentrations of Triton X15, 45 and 100. A possible dependence of the tester strain's beta-galactosidase production and its growth inhibition on the HLB of the non-ionic surfactants added is discussed.

4-Nitroquinoline-1-oxide↗

PubMed1996

Evaluation of defined media suitable for isolation of auxotrophic mutants of mycobacteria.

In order to investigate the production of auxotrophs of slow growing mycobacterial pathogens, an evaluation of defined liquid and solid media suitable for Mycobacterium tuberculosis, Mycobacterium bovis and Mycobacterium paratuberculosis was undertaken. Five defined liquid media were evaluated. A number of solid support matrices was added to the liquid media to produce solid media for evaluation. Tween 80 was added to all media to produce diffuse homogeneous growth. Although satisfactory growth in defined liquid media was achieved with all strains tested, poor growth was generally observed in the equivalent defined solid medium for strains belonging to the tuberculosis complex. Only M. paratuberculosis produced satisfactory growth on defined solid media, especially on Middlebrook 7H9. The inhibitory effect of Tween 80 and the presence of inhibitory factor(s) in agar were confirmed. Partial removal or inactivation of these factors by the addition of absorbents to the media was achieved.

Agar↗

PubMed1997

Optimization of catalase biosynthesis in submerged cultures of Aspergillus niger mutant.

The effect of some medium components, viscous substances and metabolic inhibitors, on catalase production by mutant Aspergillus niger has been studied in shake culture. Altering the composition of the basal medium, particularly substituting NaNO3 for KNO3, and peptone for yeast extract brought an increase in extra- and intracellular catalase activity by 1.5- and 3-fold, respectively. The addition of 2.0-6.0 mg sodium alginate or pectin/ml as viscous additive to the medium, containing glucose as carbon source, increased the medium viscosity and catalase production in shake culture by about 2.8- to 3.0-fold. The highest yield of extracellular catalase activity of A. niger was obtained in the presence of sodium orthovanadate and Triton X-100, which improved the activity of this enzyme by about 1.5-2.2-fold. A significant increase in intracellular catalase activity was observed in the presence of hematin, Tween 80 and sodium orthovanadate (1.7-, 1.6- and 1.4-fold respectively). The time course of growth and enzyme production by A. niger in the optimized medium is also reported.

Alginates↗

PubMed1997

Effect of certain nutrients on the production of dextransucrase from Leuconostoc mesenteroides NRRL B-512F.

The effects of certain nutrients on dextransucrase (sucrose: 1,6-alpha-d-glucan 6-alpha-d-glucosyltransferase EC 2.4.1.5) production from Leuconostoc mesenteroides NRRL B-512F were studied. An increase in concentration of sucrose to 4% in the enzyme production medium resulted in the increase of activity of dextransucrase. Higher enzyme yields were obtained at low yeast extract and high phosphate concentrations. The presence of peptone and beef extract in the medium in addition to 2% yeast extract resulted in an enhanced production of dextransucrase. The enzyme activity increased by 30% by both peptone and beef extract. Addition of Tween 80 to the medium enhanced the production of enzyme and the activity was increased by 25%. Magnesium ions stimulated the activity marginally. Sodium fluoride enhanced the activity of dextransucrase by 25%.

Culture Media↗

PubMed1979

Alcohol-induced switching over of metabolic flux in Streptomyces noursei JA0 3890b.

Short-chain alcohols, benzyl alcohol and Tween 20 were found capable of switching over the metabolic flux in Streptomyces noursei JA 3890b from the preference of oxidative deamination of alanine towards the reinforced acquisition of NH4+. These changes were correlated to the decrease of the ratio of saturated to olefinic fatty acids in the mycelium, suggesting that alcohols and other polar lipophilic compounds can interfere with the biosynthesis and the function of the cytoplasmic membrane in Streptomyces.

1-Propanol↗

PubMed2002

A comparison of commonly used polyethoxylated pharmaceutical excipients on their ability to inhibit P-glycoprotein activity in vitro.

P-glycoprotein (P-gp), a multidrug resistance (MDR) protein encoded by the MDR1 gene in humans, is responsible for the efflux of structurally diverse drugs. Previous studies in our laboratory have shown that excipients such as poly(ethylene)glycol (PEG)-300, Cremophor EL, and Tween 80 inhibit P-gp activity in Caco-2 cell monolayers. The objective of this study was to determine the effects of these excipients in an MDR1- transfected Madin Darby Canine Kidney (MDR1-MDCK) cell line and to compare the results with those obtained from Caco-2 cells. The results presented herein show that PEG-300 (20%, v/v) causes almost complete inhibition of P-gp activity in both Caco-2 and MDR1-MDCK cell monolayers, whereas Cremophor EL (0.1%, w/v) and Tween 80 (0.05%, w/v) only partially inhibit P-gp activity in Caco-2 cells. Cremophor EL (0.1%, w/v) and Tween 80 (0.05%, w/v) were inactive as P-gp inhibitors in MDR1-MDCK cell monolayers. This inability of Tween 80 and Cremphor EL to inhibit P-gp activity in MDR1-MDCK cells may be related to differences in the interactions of the surfactants with these different cell membranes. PEG-induced changes in P-gp activity are probably related to changes in the fluidity of the polar head group regions of cell membranes.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2003

Microemulsions for dermal drug delivery studied by dynamic light scattering: effect of interparticle interactions in oil-in-water microemulsions.

Dynamic light scattering (DLS) was used to study the droplet size and the droplet interaction of o/w microemulsions (MEs) consisting of oils, a blend of a high and a low hydrophilic-lipophilic balance (HLB) surfactant, and a hydrophilic phase (propylene glycol/water). Like many MEs, these systems could not be diluted to infinite dilution without phase separation. Consequently, to allow a meaningful calculation of droplet diameter from data obtained from DLS, it is necessary to correct scattering measurements in high concentration regions for the nonideality arising from interparticle interaction. Scattering data were corrected for interparticle interaction using a suitable interaction model proposed for our systems. From the total interparticle interaction energy, coagulation time was calculated. The ratio between rapid and slow coagulation was of the order of 10(100), which is consistent with the observed stability of the MEs studied.

Administration, Cutaneous↗