Evidence of phospholipids and mucopolysaccharides in the cystic fluid from a patient with generalized tissue calcification

Analyses of the cystic fluid from a patient with massive tissue calcification showed a significant amount of acid mucopolysaccharides (mainly hyaluronic acid) and phospholipid-polypeptide complexes. The possible role of those molecules in this type of calcinosis is discussed.

99mTc-Sn oxine complex: a radiocompound with possibilities for lymphographic studies

A very simple method of preparation of 99mTc-Sn oxine which shows a high yield of radioactive labeling is described in this paper. After intravenous injection the radiocolloid is taken up mainly by the reticuloendothelium. The subcutaneous administration indicates a good migration through the tissues and a high accumulation by lymph nodes, characteristics which point to the usefulness of this radiocompound for lymphographic studies.

Radioactive nucleic acids-precursors: their potential value as tumor-localizing agents

The distribution of 125I-uracil and 125I-deoxyuridine in tumor-bearing animals has been studied. 125I-deoxyuridine shows the characteristics of a tumor-scanning agent. The metabolic incorporation by tumors of this DNA-precursor indicates a potential value of this radiocompound for their detection, differentiation and follow-up of their evolution after therapy.

On the mechanism of accumulation of 67Ga by tumors

There is strong experimental evidence indicating that a competitive binding of 67Ga3+ to Ca2+- and Mg2+-binding sites rather than a metabolic process is involved in the accumulation of this radioisotope. These observations suggest that in tumors, as well as in other inflammatory and infectious processes, the most important role in 67Ga accumulation is played by a higher availability of those binding sites than in normal tissue.

Hepatocarcinogenesis by thioacetamide: correlations of histological and biochemical changes, and possible role of cell injury

Hepatocarcinogenesis in rats produced by prolonged feeding of thioacetamide appears as a progressive phenomenon in which morphological changes are associated with important biochemical modifications. It seems most likely that changes in the permeability of cell membrane induced by the carcinogen are responsible for increased intracellular accumulation of Ca2+, and for the ensuring of cell injury produced by Ca2+ overloading of the mitochondria. This calcification of the mitochondria may play a role in the neoplastic transformation of the cell, especially as far as it concerns metabolic behavior and the genetic specification of the permeability characteristics of the transformed cell membrane. The increased synthesis of acid glycosaminoglycans suggests their involvement in calcium-mediated control of tumor development and growth.

In vivo synthesis of acid mucopolysaccharides by Ehrlich ascites tumor cells

The biosynthesis and intracellular distribution of acid mucopolysaccharides in Ehrlich ascites tumor cells was studied in vivo by means of the precursors 35S-sulfate, 3H-glucosamine and 14C-galactosamine. It was found that the acid mucopolysaccharide present in the ascitic fluid supernatant is hyaluronic acid. Hyaluronic acid appears to be of extracellular origin, and it is bound to proteins of the cell membrane. The ascites cells exhibit a very active production of sulfated mucopolysaccharides particularly at the mitochondria and cell membrane level. Chondroitin sulfate A is the major component but also the isomers B and C are present. The possible role of chondroitin sulfate A in the development of neoplastic characteristics of the cell is discussed.

On the accumulation of 57Co by pancreas

The in vivo distribution of various 57Co-labelled compounds has been studied. 57Co-citrate is concentrated by pancreas and when injected together with ferric citrate the pancreas uptake is increased while it decreases in liver and kidney.

On the role of the cell coat glycoproteins in the permeability of the cell

The release of a part of the cell coat of Ehrlich ascites cells by chelation with ethylenediamine-tetraacetic acid modifies significatively the uptake of various radioactive molecules. This phenomenon seems to be related to a change in the permeabililty of the cell membrane. The chemical analyses of the released material appear to indicate that glycoproteins are involved in that change and that their release modifies the structural and physiological characteristics of the cell membrane.

On the role of tumor cell surface in the accumulation of radioisotopes

The effects of electrical charge and structural modifications of the ascites tumor cell surface on the uptake of several radiocompounds have been investigated. Changes in its electrical surface charge provoke variations in the radioactivity incorporation which appear to be selective for chelated or ionic radioisotopes. The release of a part of the cell "coat" by EDTA affects profoundly the incorporation of radioisotopes in a process which seems to be related to cell membrane permeability changes. The relationships between cell surface changes and radiocompounds accumulation are discussed.

Metabolism of calcium and magnesium in liver during acute thioacetamide intoxication

The metabolism of calcium and magnesium in liver of thioacetamide treated rats has been studied. A change in the semipermeability of the cell membrane to calcium, magnesium, sodium and potassium was observed. The variations in the concentration of extra- and intracellular cations indicates that an undiscriminated in- and outflux of those ions takes place at the time of highest calcium deposition. This change in the cell membrane permeability seems to be related to modifications in the phospholipid metabolism. An increased incorporation of 32P into the acidic phospholipids (phosphatidyl ethanolamine and phosphatidyl serine) suggests their involvement in the physiological changes of the cell membrane. The results also point out the existence of a hormonally determined susceptibility of the cell membrane to undergo those changes.

57Co-hematoporphyrin accumulation by experimental tumors

The in vivo distribution of 57Co-hematoporphyrin in adenocarcinoma BW10232-bearing mice has been studied. Tumor-bearing and normal animals exhibit similar patterns of radioactivity accumulation. Twenty-four hours after the administration of the radiocompound the ratios tumor to blood and tumor to muscle indicate a potential value of this radioactive porphyrin for the detection of some types of tumor.

Changes in phosphorus metabolism during the tumor growth inhibition by metabolic acidosis

Ammonium chloride-induced metabolic acidosis produces an increase of the phosphorus turnover rate in tumor tissue. The lower blood protein-bound 32P seems to indicate that the high phospholipid turnover observed in tumor may be related to an increased molecular degradation. It seems likely that this phenomenon together with the augmented release of phospholipid-bound calcium may induce important changes in the cell membrane behavior.

35S incorporation into sulfated mucopolysaccharides from embryonic, normal, and neoplastic liver cells

The incorporation of 35S into the sulfated mucopolysaccharides from hepatoma, normal and embryonic liver cells has been studied by means of anion exchange chromatography of the isolated mucopolysaccharide. Comparatively to liver cells, while showing a higher labeling of low sulfated mucopolysaccharides the hepatoma cells incorporate much less 35S into the heparin fraction.

On the Accumulation of 57Co by Pancreas

The in vivo distribution of various 57Co-labelled compounds has been studied. 57Co-citrate is concentrated by pancreas and when injected together with ferric citrate the pancreas uptake is increased while it decreases in liver and kidney.

Extracellular Ca2+ and Mg2+ and cellular metabolism of phospholipids

High extracellular concentration of Ca2+ inhibits the incorporation of 32P into the cellular phospholipids. This effect is more significant in neoplastic than in normal cells, and it is accompanied by an increase of the percentual incorporation into the lecithin fraction.