Conventional and Preparative Electrophoretic Separation of Some Urinary Porphyrins and Porphyrin Precursors

1970 ◽  
Vol 16 (4) ◽  
pp. 331-334 ◽  
Author(s):  
J Fischl ◽  
F Eichhorn ◽  
A Ruttenberg ◽  
Ch Major
Keyword(s):  
Small Volume ◽  
Aminolevulinic Acid ◽  
Membrane Filter ◽  
Ammonium Hydroxide ◽  
Filter Medium ◽  
Electrophoretic Separation ◽  
Urinary Porphyrins

Abstract Urinary porphyrins are concentrated by adsorption on talc, from which they are eluted with ammonium hydroxide. The eluate is electrophoresed on a membrane filter medium in an alkaline buffer (pH 10.5) for 10 to 20 min. Porphobilinogen and δ-aminolevulinic acid in urine are separated within 90 min by "small-volume" electrophoresis in a pH 2.2 buffer.

Improved Membrane Filter Medium for the Detection of Coliform Organisms

1958 ◽  
Vol 50 (2) ◽  
pp. 193-196 ◽  
Author(s):  
Charles W. Fifield ◽  
Charles P. Schaufus
Keyword(s):  
Membrane Filter ◽  
Filter Medium

Measurement of urinary porphyrins and porphyrin precursors in Dutch hospital laboratories: a review of quality control over 5 years

2003 ◽  
Vol 40 (4) ◽  
pp. 417-418 ◽  
Author(s):  
Floris M. J. Zuijderhoudt ◽  
Cas W. Weykamp ◽  
Hans L. Willems
Keyword(s):  
Quality Control ◽  
Aminolevulinic Acid ◽  
Laboratory Diagnosis ◽  
Low Grade ◽  
Dutch Hospital ◽  
Coefficients Of Variation ◽  
Control Scheme ◽  
Quality Control Scheme ◽  
Very High ◽  
Urinary Porphyrins

Background: We evaluated a quality control scheme for the measurement of urinary uroporphyrin, coproporphyrin, total urinary porphyrins and precursors of urinary porphyrins, δ-aminolevulinic acid and porphobilinogen that was performed in The Netherlands during a period of 5 years. Methods: Six quality control samples were distributed each year to the participating laboratories. Mean concentrations and the corresponding coefficients of variation were calculated. Results: Coefficients of variation varied widely and were very high in the concentration ranges that can be found in patients with low-grade porphyria. Conclusion: Commutable calibrators are needed to improve the laboratory diagnosis of porphyria.

scholarly journals RECOVERY OF WASTE OINTMENTS BY ULTRAFILTRATION METHOD

2021 ◽  
pp. 75-83
Author(s):  
Yuliya Melnyk ◽  
Andriy Melnyk
Keyword(s):  
Small Volume ◽  
Membrane Filter ◽  
Free Water ◽  
Filter Element ◽  
Metal Mesh ◽  
Filtration Process ◽  
Batch Mode ◽  
Pass Through ◽  
Degree Of Purification

Ultrafiltration devices are currently being developed and manufactured around the world, and productivity varies greatly from 1 to 300,000 m/day. In practice, ultrafiltration parameters are used and performed in batch, semi-periodic and continuous modes. Continuous and semi-periodic modes are mainly used for large volumes of liquids. In the case of a small volume, the batch mode prefers the continuous mode - the area of the membrane is smaller and it is easier to clean. The deposition of spent grease is based on the fact that mechanical impurities and water are in a suspended state and settle over time. When selecting the process of restoring the quality of the lubricant to the required level, first use a mechanical cleaning method to remove free water and hard dirt. In practice, rough cleaning of the lubricant is carried out using filter elements made of metal mesh with a filtration fineness of 60 ... 80 μm. A complex filter element made of non-woven materials is used for fine cleaning. Type of oil filter "FMN" (cleaning accuracy 15 ... 20 microns). However, these filters cannot provide a degree of purification of the spent lubricant, as the latter contains a large amount of carbon contaminants, preferably with a particle size of less than 5 μm. In the process of ultrafiltration of oil, the initial stream is separated and concentrated. Varnish, resin and other small contaminants are retained by the superporous layer on the surface and are continuously washed away by a tangential flow of purified oil. Only cleaned grease can pass through the membrane. This allows for a long filtration process without replacing the membrane filter element. The ultrafiltration process is performed at a pressure of 0.3-1 MPa and a flow rate of 2-5 m/s, using membranes with a size of 0.1-0.005 μm.

Protamine-DNA interaction

1978 ◽  
Vol 36 (2) ◽  
pp. 200-201
Author(s):  
D.P. Bazett-Jones ◽  
F.P. Ottensmeyer
Keyword(s):  
Small Volume ◽  
Double Helix ◽  
Dna Interaction ◽  
Dark Field ◽  
Sperm Head ◽  
Nuclear Proteins ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Dna Double Helix ◽  
Positively Charged

Dark field electron microscopy has been used for the study of the structure of individual macromolecules with a resolution to at least the 5Å level. The use of this technique has been extended to the investigation of structure of interacting molecules, particularly the interaction between DNA and fish protamine, a class of basic nuclear proteins of molecular weight 4,000 daltons.Protamine, which is synthesized during spermatogenesis, binds to chromatin, displaces the somatic histones and wraps up the DNA to fit into the small volume of the sperm head. It has been proposed that protamine, existing as an extended polypeptide, winds around the minor groove of the DNA double helix, with protamine's positively-charged arginines lining up with the negatively-charged phosphates of DNA. However, viewing protamine as an extended protein is inconsistent with the results obtained in our laboratory.

The Theoretical Contrast in Scanning and Conventional High Resolution Microscopes

1969 ◽  
Vol 27 ◽  
pp. 170-171
Author(s):  
E. Zeitler ◽  
M. G. R. Thomson
Keyword(s):  
Small Volume ◽  
Volume Element ◽  
Optical Processing ◽  
Image Construction ◽  
Object Interaction ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Optical Treatment ◽  
Electron Microscopes ◽  
Intensity Contrast

In the formation of an image each small volume element of the object is correlated to an areal element in the image. The structure or detail of the object is represented by changes in intensity from element to element, and this variation of intensity (contrast) is determined by the interaction of the electrons with the specimen, and by the optical processing of the information-carrying electrons. Both conventional and scanning transmission electron microscopes form images which may be considered in this way, but the mechanism of image construction is very different in the two cases. Although the electron-object interaction is the same, the optical treatment differs.

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