Salt Precipitation Method Research Articles

Analysis of hyaluronic acid in the diagnosis of malignant mesothelioma.

Using a modified papain digestion cetylpyridinium salt precipitation method, glycosaminoglycans were isolated from 21 mesotheliomas, 34 primary lung carcinomas, 12 carcinomas of other sites, and 7 soft tissue sarcomas. Qualitatively, hyaluronic acid (HA) was present in 20 of 21 mesotheliomas, about half of the primary lung adenocarcinomas, and all of the soft tissue sarcomas. On the average, HA constituted 45% of the total glycosaminoglycans in the mesotheliomas and 28% of the total in the lung cancers. Quantitatively, mesotheliomas contained statistically greater amounts (mean value, 0.74 mg/g) of HA than primary lung adenocarcinomas (mean value, 0.08 mg/g), but were not statistically different from soft tissue sarcomas (mean value, 2.01 mg/g) or primary ovarian serous neoplasms (mean value, 0.92 mg/g). The study concludes that, contrary to previous reports, HA is neither the sole nor the predominant glycosaminoglycan in most mesotheliomas, but, given the proper clinical and histologic setting, the finding of sufficiently high levels (greater than 0.4 mg/g dry tissue extract) supports the diagnosis of mesothelioma when the alternative diagnosis is primary adenocarcinoma of lung.

FURTHER CHARACTERIZATION OF THE OVINE LUTROPIN α AND β SUBUNITS PREPARED BY THE SALT PRECIPITATION METHOD

The subunits of ovine lutropin prepared by acid dissociation and salt precipitation were characterized by end group analysis, tryptic peptide mapping, SDS gel electrophoresis and biological activity. No evidence of internal peptide cleavage was found in the alpha subunit. The subunits possessed low activity. The alpha and beta subunits recombined effectively to generate a complex that had full receptor binding activity and in vitro biological activity. The recombinants of subunits prepared by countercurrent distribution showed only 50% activity in both assays. The salt precipitation method alpha subunit could be completely reduced and reoxidized in the absence of denaturants. The reoxidized alpha subunit combines with the native beta subunit generating full activity. However, this recombined hormone tends to lose activity with time, suggesting that the reoxidation may not fully restore the native structur of the reduced alpha subunit. The native lutropin alpha subunit effectively combined with follitropin beta subunit generating complete follitropin activity.

Physical and Chemical Properties of Human Embryonic Prealbumin and its Association with Malignancies

Human embryonic prealbumin (EPA) was purified from pooled fetal sera by a combination of the salt precipitation methods, ion‐exchange chromatography and electro‐isofocusing. Purified EPA preparations had about 80% peptide and 20% carbohydrate including mannose, fucose, glucose, galactose, glucosamine and galactosamine. Amino acid composition of EPA may be characterized by high concentration of aspragin. glutamine acids and proline but very low concentration of methionine.By immunodiffusion in agar, EPA was found in all fetal sera and in some malignant tissue homogenates including carcinomas of ovary, breast, stomach, lung, kidney, and intestinal tract.

On the reliability of the lead salt precipitation method of acid phosphatase localization in plant cells

Fixation of cells with glutaraldehyde (5.0%, pH 6.7) was found to facilitate both the penetration of substrate (p-nitrophenyl phosphate) into cells and the leaking out of intracellular phosphate ions. 64% of the original activity survived the fixation for at least 24 hours. Lead ions added to the incubation medium at 6 mM neither accelerated nonenzymatic hydrolysis of the substrate, nor completely inactivated the enzyme activity. Lead ions at concentrations above 6 mM formed an insoluble compound with p-nitrophenyl phosphate, resulting in a decrease in the concentration of free substrate and lead ions. Phosphate ions liberated from substrate could not be completely trapped by lead ions even at above 6 mM, suggesting the possibility of intracellular migration of phosphate ions.

Interphase chromosomal deoxyribonucleoprotein isolated as a discrete structure from cultured cells

A new procedure is described for the preparation of interphase chromatin from cultured mouse cells (line P815). The primary objective of this procedure was to eliminate exchanges of histones between deoxynucleoprotein molecules; this objective is shown experimentally to have been attained. The chromatin is released from cells by the non-ionic detergent Nonidet P40 in medium of low ionic strength (0.1 mM-KNa 2PO 4), and may then be sedimented as a structure which conserves the general form and ultrastructural characteristics of chromatin within the cell. The nuclear envelope cannot be detected in these structures by electron microscopy, and their content of choline-containing phospholipids is less than 10% of that of nuclei. The maintenance of form in this structure must thus depend on properties of the chromatin itself, and possibly on the more compact peripheral chromatin. Soluble DNP † † Abbreviations used: DNP, deoxyribonucleoprotein. prepared by shearing these structures has the same relative contents of DNA, histones, non-histone proteins and RNA as DNP prepared by standard methods. Analyses by electrophoresis on polyacrylamide gels of the non-histone proteins reveals certain differences from the pattern of these proteins in DNP prepared by a salt precipitation method. The template activity for RNA synthesis, in the presence of Escherichia coli RNA polymerase of sheared, soluble DNP prepared by this procedure, is comparable to that of DNP prepared by other methods. However, in the absence of exogenous RNA polymerase the rate of RNA synthesis by structured (unsheared) chromatin is about ten times higher than the rate using sheared DNP. The rapid removal of the nuclear envelope in this lysis procedure allowed experimental examination of the origin of the histones and non-histone proteins of DNP. When DNP was prepared from a mixture of two populations of cells, one containing DNA distinguishable by a density label and the other containing radioactively labelled proteins, radioactive proteins were found exclusively in DNP of normal density, and not in dense DNP and vice versa. It is concluded that the proteins of DNP prepared in this way are not acquired during the preparation procedure but were already associated with DNA in vivo, and that other proteins are not bound non-specifically to DNA during the preparation of DNP. When a mixture of DNP molecules prepared, in this way is precipitated in 150 m m-NaCl and redissolved, some radioactively labelled histones migrate onto dense DNA molecules. This procedure is suitable for routine, quantitative isolation of chromosomal DNP from small numbers of cells; it is also applicable to cells of other cultured lines.

Effect of epidermal damage upon serum polysaccharides.

Summary and conclusionsEpidermal thermal injury in dogs resulted in an elevation of total polysaccharide in both lymph and serum and of the polysaccharide of both the albumin and α-globulin (pseudoglobulin) fractions isolated by salt precipitation methods. The elevation of the polysaccharide of the albumin fraction was shown to be due to an elevation of the mucoprotein polysaccharide. The mucoprotein content of the lymph and serum from the same animal were nearly the same indicating that this component may pass easily between tissue fluids and blood plasma. Preliminary studies of the effects of adrenocorticotropic hormone on animals with epidermal thermal injuries indicate that this substance has no effect on the elevation of mucoprotein, but may repress the elevation of α-globulin polysaccharide.

ON THE DIBASIC ACIDS IN JAPAN WAX

Abstract (1) As “japanic acid” of Geitel and van der Want appears not the only dibasic acid in Japan wax, this name has been reserved for a while, and the expression of the “Japan wax dibasic acids” or more simply the “dibasic acids” is used in this paper. (2) Basing on the difficult solubility of the dibasic acids in petroleum ether, a method for their approximate determination has been proposed. The results obtained by this method show that the content of the dibasic acids in the mixed fatty acids of Japan wax amounts to 5–6%, which are far greater than hitherto considered. (3) For the preparative separation of the dibasic acids, the lead salt precipitation method and the ester distillation method have been found to be most convenient. (4) As the results of the chemical examination of the dibasic acids, it has been concluded that the main constituent of the acids is heneicosane dicarboxylic acid, C23H44O4, but probably eicosane dicarboxylic acid, C22H42O4 also occurs in a fair proportion. (5) As a peculiar property of the dibasic acids, it has been found that the comparatively small addition of them to fatty and waxy substances makes the crystalline structure of these substances finer and more opaque, and at the same time gives certain coherency and tenacity. (6) The characteristic property of Japan wax that it may be kneaded to a “mochi”-like mass without adhering to the fingers is due to the presence of the glycerides of the dibasic acids.