Isolation of Hyaluronic Acid and Chondroitin-sulphuric Acid from Human Aortae

The mean values and standard deviations for the concentrations of the hyaluronic acid and chondroitin sulphuric acid fractions isolated from 11 specimens of human skin were 24.5 ± 5.7 and 26.2 ± 4.7 mgm. per 100 gm. of fresh tissue, respectively.The individual differences in the concentrations of these substances were masked by the technical errors. The small variations in moisture and ash content of the skin did not contribute appreciably to the uncertainty of the concentration values. The purity of the products, determined by their amino sugar content, approximated 60%, which value compared favorably with those obtained by other workers.The content of hexosamine and uronic acid identified both fractions as acid mucopolysaccharides. The release of reducing substances, including N-acetyl hexosamine, from the hyaluronic acid fraction by hyaluronidase paralleled the action of the enzyme upon hyaluronate from umbilical cord. The chondroitin sulphuric acid fraction, which was relatively resistant to the action of hyaluronidase, was assumed to be identical with the chondroitin sulphatelike substance that Meyer and Chaffee isolated from pig skin.

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A non-cyanide method of electropolishing silver

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107873 ◽

1978 ◽

Vol 36 (1) ◽

pp. 146-147

Author(s):

R. L. Lyles ◽

S. J. Rothman ◽

W. Jäger

Keyword(s):

Electron Microscopy ◽

Sulphuric Acid ◽

Methyl Alcohol ◽

Health Hazards ◽

Silver Alloy ◽

High Quality ◽

Silver Alloys ◽

Free Sample ◽

Specimen Quality ◽

Standard Techniques

Standard techniques of electropolishing silver and silver alloys for electron microscopy in most instances have relied on various CN recipes. These methods have been characteristically unsatisfactory due to difficulties in obtaining large electron transparent areas, reproducible results, adequate solution lifetimes, and contamination free sample surfaces. In addition, there are the inherent health hazards associated with the use of CN solutions. Various attempts to develop noncyanic methods of electropolishing specimens for electron microscopy have not been successful in that the specimen quality problems encountered with the CN solutions have also existed in the previously proposed non-cyanic methods.The technique we describe allows us to jet polish high quality silver and silver alloy microscope specimens with consistant reproducibility and without the use of CN salts.The solution is similar to that suggested by Myschoyaev et al. It consists, in order of mixing, 115ml glacial actic acid (CH3CO2H, specific wt 1.04 g/ml), 43ml sulphuric acid (H2SO4, specific wt. g/ml), 350 ml anhydrous methyl alcohol, and 77 g thiourea (NH2CSNH2).

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