Influences of molecular weight, molecular size, flux, and recovery for aromatic pesticide removal by nanofiltration membranes

Summary43 normal volunteers, 3 patients with thrombophlebitis, and 1 patient with a high platelet adhesiveness and a history of thrombophlebitis have received dextran and its action on the mechanism of haemostasis has been studied. Platelet adhesiveness has been investigated by a slight modification of Hellem’s methods for whole blood and plasma. Dextran with a mean molecular weight of 70,000 produced a markedly lowered platelet adhesiveness together with a moderate prolongation of the Ivy bleeding time. Factor VIII was decreased by about 50% and factor V, factor IX and fibrinogen were decreased slightly more than could be expected from haemodilution alone. No fibrinolysis occurred. Dextran of lower molecular size was less potent. The possible use of dextrans as a thrombosis prophylactic agent is discussed.

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Effect of extractant and molecular size on the optical and chemical properties of soil humic acids

Soil Research ◽

10.1071/sr9690229 ◽

1969 ◽

Vol 7 (3) ◽

pp. 229 ◽

Cited By ~ 50

Author(s):

JHA Butler ◽

JN Ladd

Keyword(s):

Molecular Weight ◽

Amino Acid ◽

Humic Acids ◽

Gel Filtration ◽

Chemical Properties ◽

Molecular Size ◽

Carboxyl Content ◽

Peptide Bonds ◽

Molecular Weights ◽

Amino Acid Contents

Humic acids extracted from soil with sodium pyrophosphate have greater proportions of lower molecular weight material, less acid-hydrolysable amino acid nitrogen contents, but greater carboxyl contents and extinction values (260 and 450 nm) than humic acids extracted subsequently from the same sample with alkali. Humic acids extracted with alkali from fresh soil samples have intermediate values. Extinction values at 260 nm are directly correlated with carboxyl contents for a given soil. Different crop histories have no significant effect on the measured properties of the extracted humic acids. An alkali-extracted humic acid has been fractionated by gel filtration into seven fractions of different nominal molecular weight ranges. As the molecular weights of the fractions increase, both aliphatic C-H (based on infrared absorption at 2900 cm-1) and acid-hydrolysable amino acid contents increase, whereas extinction values at 260 nm and carboxyl contents decrease. The infrared spectra of the high molecular weight fractions have peaks at 1650 and 1510 cm-1 which correlate with acid-hydrolysable amino acid contents and which correspond to amide I and II bands of peptide bonds. Alkaline hydrolysis to split peptide bonds eliminates both these peaks. The spectra also have peaks at 1720 and 1210 cm-1 which correlate with the carboxyl content.

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The molecular form of acetylcholinesterase as determined by irradiation inactivation (Short Communication)

Biochemical Journal ◽

10.1042/bj1370123 ◽

1974 ◽

Vol 137 (1) ◽

pp. 123-125 ◽

Cited By ~ 33

Author(s):

S. R. Levinson ◽

J. C. Ellory

Keyword(s):

Molecular Weight ◽

Short Communication ◽

Molecular Form ◽

Electric Organ ◽

Molecular Size ◽

Erythrocyte Ghosts ◽

Multiple Forms ◽

Electrophorus Electricus ◽

Membrane Bound

The molecular size of acetylcholinesterase (EC 3.1.1.7) from the electric organ of Electrophorus electricus and erythrocyte ‘ghosts’ was estimated in both membrane-bound and purified preparations by irradiation inactivation. Results suggest that the form of the enzyme in the membrane is a monomer of molecular weight approx. 75000 and that multiple forms of the enzyme observed in solubilized preparations are aggregates of this monomer.

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Correlations between retention volume and molecular size parameters in gel permeation chromatography of small molecules

Australian Journal of Chemistry ◽

10.1071/ch9750189 ◽

1975 ◽

Vol 28 (1) ◽

pp. 189 ◽

Cited By ~ 4

Author(s):

RA Shanks

Keyword(s):

Molecular Weight ◽

Small Molecules ◽

Organic Molecules ◽

Retention Volume ◽

Molecular Size ◽

Gel Permeation Chromatography ◽

Molar Volumes ◽

Small Organic Molecules ◽

Molecular Dimension ◽

Gel Permeation

Gel permeation columns of Bio Beads S-X8 have been used to provide separation of oligomers and other small organic molecules. Results show successful separations up to molecular weight c. 600. The retention times of compounds have been correlated with the largest molecular dimension of the molecules and also with molar volumes.

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Localization of heparin and low-molecular-weight heparin in the rat kidney

Thrombosis and Haemostasis ◽

10.1160/th03-10-0645 ◽

2004 ◽

Vol 91 (05) ◽

pp. 927-934 ◽

Cited By ~ 5

Author(s):

Vivian Douros ◽

Thomas Podor ◽

Stephen Shaughnessy ◽

Jeffrey Weitz ◽

Edward Young

Keyword(s):

Molecular Weight ◽

Low Molecular Weight Heparin ◽

Rat Kidney ◽

Organic Anion ◽

Molecular Size ◽

Immunohistochemical Analysis ◽

Immunoperoxidase Staining ◽

Low Molecular Weight ◽

Renal Tubular Cells ◽

Renal Tubular

SummaryUnfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) are cleared, at least in part, by the kidneys through a poorly understood process. This study was undertaken to explore the mechanism of renal clearance of these drugs. Rats were given fluorescein-5-isothiocyanate (FITC)-labeled UFH or LMWH intravenously. At intervals after injection, rats were euthanized and the kidneys were harvested and subjected to immunohistochemical analysis and fluorescence microscopy. Both UFH and LMWH were localized to renal tubular cells and no immunoperoxidase staining or fluorescence was detected in glomeruli. Autoradiography demonstrated similar intracellular distribution of radio-labeled UFH suggesting that this phenomenon is independent of the method used to label heparin. Fluoresence in the tubules increased as a function of time after UFH injection, but reached a plateau after LMWH injection suggesting that the rate of renal tubular uptake depends on the molecular size of the heparin. When administered prior to FITC-labeled UFH or LMWH, probenecid, a renal organic anion inhibitor, decreased the renal tubular uptake of the heparins, whereas cimetidine, a renal organic cation inhibitor, had no effect. These findings suggest that renal excretion of UFH and LMWH primarily reflects tubular uptake via an organic anion transport mechanism.

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The isocitrate dehydrogenases of Acinetobacter lwoffi. Separation and properties of two nicotinamide–adenine dinucleotide phosphate-linked isoenzymes

Biochemical Journal ◽

10.1042/bj1300211 ◽

1972 ◽

Vol 130 (1) ◽

pp. 211-219 ◽

Cited By ~ 14

Author(s):

Colin H. Self ◽

P. David J. Weitzman

Keyword(s):

Molecular Weight ◽

Ph Dependence ◽

Gel Filtration ◽

Deae Cellulose ◽

Nicotinamide Adenine Dinucleotide Phosphate ◽

Molecular Size ◽

Ion Exchange Chromatography ◽

Exchange Chromatography ◽

Low Concentrations ◽

Stimulation Of

Two isoenzymes of NADP-linked isocitrate dehydrogenase have been identified in Acinetobacter lwoffi and have been termed isoenzyme-I and isoenzyme-II. The isoenzymes may be separated by ion-exchange chromatography on DEAE-cellulose, by gel filtration on Sephadex G-200, or by zonal ultracentrifugation in a sucrose gradient. Low concentrations of glyoxylate or pyruvate effect considerable stimulation of the activity of isoenzyme-II. The isoenzymes also differ in pH-dependence of activity, kinetic parameters, stability to heat or urea and molecular size. Whereas isoenzyme-I resembles the NADP-linked isocitrate dehydrogenases from other organisms in having a molecular weight under 100000, isoenzyme-II is a much larger enzyme (molecular weight around 300000) resembling the NAD-linked isocitrate dehydrogenases of higher organisms.

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Characterization of proteins from the cytoskeleton of Giardia lamblia

Journal of Cell Science ◽

10.1242/jcs.59.1.81 ◽

1983 ◽

Vol 59 (1) ◽

pp. 81-103 ◽

Cited By ~ 1

Author(s):

R. Crossley ◽

D.V. Holberton

Keyword(s):

Molecular Weight ◽

Sodium Dodecyl Sulphate ◽

Giardia Lamblia ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Gel Filtration ◽

Molecular Size ◽

Molecular Weights

Proteins from the axonemes and disc cytoskeleton of Giardia lamblia have been examined by sodium dodecyl sulphate/polyacrylamide gel electrophoresis. In addition to tubulin and the 30 X 10(3) molecular weight disc protein, at least 18 minor components copurify with the two major proteins in Triton-insoluble structures. The most prominent minor bands have the apparent molecular weights of 110 X 10(3), 95 X 10(3) and 81 X 10(3). Protein of 30 X 10(3) molecular weight accounts for about 20% of organelle protein on gels. In continuous 25 mM-Tris-glycine buffer it migrates mostly as a close-spaced doublet of polypeptides, which are here given the name giardins. Giardia tubulin and giardin have been purified by gel filtration chromatography in the presence of sodium dodecyl sulphate. Well-separated fractions were obtained that could be further characterized. Both proteins are heterogeneous when examined by isoelectric focusing. Five tubulin chains were detected by PAGE Blue 83 dye-binding after focusing in a broad-range ampholyte gel. Giardin is slightly less acidic than tubulin. On gels it splits into four major and four minor chains with isoelectric points in the pI range from 5.8 to 6.2. The amino acid composition of the giardin fraction has been determined, and compared to Giardia tubulin and a rat brain tubulin standard. Giardins are rich in helix-forming residues, particularly leucine. They have a low content of proline and glycine; therefore they may have extensive alpha-helical regions and be rod-shaped. As integral proteins of disc microribbons, giardins in vivo associate closely with tubulin. The properties of giardins indicate that in a number of respects - molecular size, charge, stoichiometry - their structural interaction with tubulin assemblies will be different from other tubulin-accessory protein copolymers studied in vitro.

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Average molecular weight of surfactants in aerosols

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-13805-2007 ◽

2007 ◽

Vol 7 (5) ◽

pp. 13805-13838 ◽

Cited By ~ 9

Author(s):

M. T. Latif ◽

P. Brimblecombe

Keyword(s):

Molecular Weight ◽

Surface Tension ◽

Atmospheric Aerosols ◽

Average Molecular Weight ◽

Molecular Size ◽

Weight Fraction ◽

Ozone Exposure ◽

Before And After ◽

Fine Mode ◽

Active Substances

Abstract. Surfactants in atmospheric aerosols determined as methylene blue active substances (MBAS) and ethyl violet active substances (EVAS). The MBAS and EVAS concentrations can be correlated with surface tension as determined by pendant drop analysis. The effect of surface tension was more clearly indicated in fine mode aerosol extracts. The concentration of MBAS and EVAS was determined before and after ultrafiltration analysis using AMICON centrifuge tubes that define a 5000 Da (5 K Da) nominal molecular weight fraction. Overall, MBAS and to a greater extent EVAS predominates in fraction with molecular weight below 5 K Da. In case of aerosols collected in Malaysia the higher molecular fractions tended to be a more predominant. The MBAS and EVAS are correlated with yellow to brown colours in aerosol extracts. Further experiments showed possible sources of surfactants (e.g. petrol soot, diesel soot) in atmospheric aerosols to yield material having molecular size below 5 K Da except for humic acid. The concentration of surfactants from these sources increased after ozone exposure and for humic acids it also general included smaller molecular weight surfactants.

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Analysis of Structural and Functional Differences of Glucans Produced by the Natively Released Dextransucrase of Liquorilactobacillus hordei TMW 1.1822

Applied Biochemistry and Biotechnology ◽

10.1007/s12010-020-03407-6 ◽

2020 ◽

Vol 193 (1) ◽

pp. 96-110 ◽

Cited By ~ 1

Author(s):

Jonas Schmid ◽

Daniel Wefers ◽

Rudi F. Vogel ◽

Frank Jakob

Keyword(s):

Molecular Weight ◽

Secondary Structure ◽

Rheological Properties ◽

Viscoelastic Fluid ◽

Size Structure ◽

Molecular Size ◽

Molecular Structures ◽

Rheological Measurements ◽

Functional Differences ◽

Functionally Diverse

AbstractThe properties of the glucopolymer dextran are versatile and linked to its molecular size, structure, branching, and secondary structure. However, suited strategies to control and exploit the variable structures of dextrans are scarce. The aim of this study was to delineate structural and functional differences of dextrans, which were produced in buffers at different conditions using the native dextransucrase released by Liquorilactobacillus (L.) hordei TMW 1.1822. Rheological measurements revealed that dextran produced at pH 4.0 (MW = 1.1 * 108 Da) exhibited the properties of a viscoelastic fluid up to concentrations of 10% (w/v). By contrast, dextran produced at pH 5.5 (MW = 1.86 * 108 Da) was gel-forming already at 7.5% (w/v). As both dextrans exhibited comparable molecular structures, the molecular weight primarily influenced their rheological properties. The addition of maltose to the production assays caused the formation of the trisaccharide panose instead of dextran. Moreover, pre-cultures of L. hordei TMW 1.1822 grown without sucrose were substantial for recovery of higher dextran yields, since the cells stored the constitutively expressed dextransucrase intracellularly, until sucrose became available. These findings can be exploited for the controlled recovery of functionally diverse dextrans and oligosaccharides by the use of one dextransucrase type.

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PDTM-30. UNDERSTANDING THE EFFECTS OF MOLECULAR SIZE ON VOLUME OF DISTRIBUTION IN CONVECTION-ENHANCED DELIVERY

Neuro-Oncology ◽

10.1093/neuonc/noz175.806 ◽

2019 ◽

Vol 21 (Supplement_6) ◽

pp. vi193-vi194

Author(s):

Erica Power ◽

Julian Rechberger ◽

Liang Zhang ◽

David Daniels

Keyword(s):

Molecular Weight ◽

Single Injection ◽

Fluorescent Microscopy ◽

Molecular Size ◽

Volume Of Distribution ◽

Sprague Dawley ◽

Convection Enhanced Delivery ◽

Microscopy Imaging ◽

Delivery Technique ◽

The Brain

Abstract BACKGROUND Diffuse midline gliomas harboring the H3K27M mutation, previously known as diffuse intrinsic pontine gliomas (DIPG), are rare and aggressive pediatric brain tumors. Over 100 clinical trials with different chemotherapeutics have failed to show any therapeutic benefit. One reason for failure is likely due to poor delivery of these agents to the brainstem. Convection-enhanced delivery (CED) is an emerging delivery technique used to directly inject the agent of interest into the brainstem under pressure. While there is evidence that this may be an effective delivery method, little work has been done to understand the optimal physical properties of these drugs. We sought characterize volume of distribution in the brain based on molecular size of the agent delivered via CED. METHODS Sprague- Dawley rats underwent a single injection of FITC-dextran (3,000 Da, 10,000 Da, 20,000 Da, 70,000 Da, 150,000 Da) via CED into the pons. Post-injection, animals were sacrificed and their brains harvested. Fluorescent microscopy imaging was used to calculate the volume of distribution of the FITC-dextran throughout the brain. RESULTS The volume of distribution (Vd) decreased exponentially according to a two-phase delay (r2= 0.94) as the molecular size of the FITC-dextran increased. The highest mean Vd (107.87mm3) was at a molecular weight of 3,000 Da, and lowest mean Vd (26.48 mm3) was at a molecular weight of 150,000 Da. ANOVA analysis was statistically significant (p= 0.0017). CONCLUSIONS As the molecular size of the FITC-dextran increased, the volume of distribution within the brain following a single injection via CED into the pons decreased. A better understanding of how drugs distribute by convection will allow us to optimize treatment regimens for DIPG tumors.

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