Biomedical subjects

L J Anghileri

Publications and source records attributed to L J Anghileri.

At least 37 records · Page 2Linked to original sources

PubMed1990

Improvement of radioactive colloid binding by tumor cells.

Treatment of P388 leukemia cells with poly-DL-lysine (Poly-lys) considerably increases the binding of colloidal chromic phosphate (32P). This augmentation of the number of particles that are bound is in direct relationship with Poly-lys concentration, and very significantly with its degree of polymerization. Treatment with Poly-lys molecular weight 77,000 shows a 100% increase of binding with 200 micrograms and of 50% with 100 micrograms. Poly-lys M.W. 8,000 presents no significant increase, and for the other molecular weights the binding is intermediate.

Adsorption↗

PubMed1990

Effects of iron-binding proteins on in vitro uptake of 67Ga-citrate by tumor cells.

A comparative study of carrier-free 67Ga-citrate uptake by Ehrlich ascites tumor cells in the presence of lactoferrin, transferrin and ferritin has demonstrated that lactoferrin considerably increases the uptake of 67Ga, and that this increase seems to be determined by its iron-load. The other iron-binding proteins assayed have a null or negative effect. Their behavior in the presence of sodium citrate supports the concept of lactoferrin-binding by the cells as responsible for the uptake. The different behavior of 67Ga-citrate iron-binding protein complexes appears to support this hypothesis.

Animals↗

PubMed1989

Enhancement of colloid uptake by tumor cell surface electrical charge modification.

Colloidal [51Cr]chromic phosphate uptake is considerably increased by preincubation of P388 ascites leukemia cells with poly(DL-lysine). The uptake increase is in direct relationship with the concentration and the degree of polymerization of poly(DL-lysine). The probable implication of cell surface electrical charge modification in these phenomena is discussed.

Animals↗

PubMed1989

Iron-binding proteins and 67Ga accumulation by tumor cells.

Tumor cells incubated with 67Ga-citrate plus lactoferrin showed a lactoferrin concentration-dependent increase of 67Ga uptake while for transferrin the effect was an inhibition. A correlation was observed between the binding of 131I-labelled lactoferrin or 131I-labelled transferrin and the uptake of 67Ga by the cells. Saturation with iron did not change significantly the effects of the iron-binding proteins. Preincubation with lactoferrin, transferrin or ferric citrate increased 67Ga uptake. The formation of a ternary complex in which 67Ga mimics iron is discussed.

Animals↗

PubMed1988

Mechanisms of gallium-67 accumulation by tumors: role of cell membrane permeability.

The effects of citrate ion on in vitro and in vivo uptake of [67Ga]citrate by tumor cells have been studied. Carrier-free [67Ga]citrate seems to follow the physical diffusion of citrate ions into the cell, and the presence of carrier gallium inhibits that diffusion, reducing considerably its uptake. These results appear to support the hypothesis that increased permeability of tumor cells is the principal cause of [67Ga]citrate accumulation by tumors.

Animals↗

PubMed1988

On the role of transferrin in 67Ga uptake by tumor cells.

In vitro uptake of 67Ga-citrate and 59Fe-citrate by DS sarcoma cells in the presence of tumor-bearing animal blood plasma showed a dramatic inhibition of both 67Ga and 59Fe uptakes: about 1/10 of 67Ga and 1/50 of the 59Fe are taken up by the cells. Subcellular fractionation appears to indicate no specific binding to cell structures, and the difference of binding seems to be related to the transferrin chelation and transmembrane transport differences.

Animals↗

PubMed1988

Modification of the ionic environment in the tumor cell by hyperthermia.

Tumor cells submitted to hyperthermia (45 degrees C) showed changes in the ionic composition: Increased calcium and decreased potassium concentrations. These changes are likely to affect vital functions of the cell. The observed decrease in ATP concentration supports the hypothesis that hyperthermia affects the ATP-dependent extrusion mechanism of the cell and, consequently, induces that ionic environment modification. Lactate production was also decreased by hyperthermia, a phenomenon that could be related to the fall in potassium concentration. The intracellular increase in Ca2-concentration during hyperthermia appears to support the earlier hypothesis on the role of Ca2+ in tumor inhibition by hyperthermia.

Animals↗

PubMed1988

In vivo changes of ionic composition of tumors treated by hyperthermia.

Experimental tumors submitted in vivo to hyperthermia, in the presence, or not, of lanthanum (La3+), have shown modifications in the concentration of extra- and intracellular cations. Sacrificed immediately after hyperthermia, only the group treated with La3+ presented ionic changes (lower magnesium and potassium). After 48 hours, in both cases calcium and sodium were increased while magnesium and potassium were decreased.

Animals↗

PubMed1987

Effects of tumor necrosis factor on tumor cell plasma membrane permeability.

Ehrlich ascites tumor cells incubated with rabbit tumor necrosis factor (TNF)-serum showed a temperature-dependent functional impairment of the plasma membrane as reflected by permeability changes. Trypan blue inclusion and Ca2+-transport were considerably increased at hyperthermia temperature. This characteristic of the TNF-plasma membrane interaction may explain the cytotoxicity of TNF.

Animals↗

PubMed1987

Effects of concanavalin A on 67Ga binding by tumor cells.

The in vitro uptakes of 67Ga-citrate and 45Ca-chloride in the presence of concanavalin A have shown that at low concentrations (10-50 micrograms/ml) 67Ga presents a significant increase not observed for 45Ca. At higher concentrations there is a sharp augmentation of both 67Ga and 45Ca incorporations. The augmentation of Trypan blue inclusion is a concomitant phenomenon at any concanavalin A concentration that indicates tumor cell plasma membrane changes in direct relationship with 67Ga uptake increase.

Animals↗

PubMed1987

Effects of hyperthermia and lanthanum on tumor cell leakage.

The effects of hyperthermia temperature and the presence of lanthanum on the release of Ehrlich's ascites cell molecules labelled with radiophosphorus have been studied. The leakage of intracellular molecules is in relationship with the temperature and the time of incubation. The phenomenon presents the characteristics of an increased passive diffusion induced by a thermotropic modification of the protein-lipid environment of the plasma membrane. The possible implication of this phenomenon on hyperthermic energy depletion and enhanced cytotoxicity of chemotherapeutics with poor cell penetration is discussed.

Animals↗

PubMed1986

Experimental evidence for the probable involvement of calcium ion transport in 67Ga uptake by tumour cells.

The study of 67Ga-citrate uptake and calcium transport in Ehrlich ascites tumour cells seems to indicate that their peculiar characteristic of increased permeability to extracellular calcium ion might be responsible for their 67Ga accumulation. Experiments performed under different conditions of extracellular calcium, temperature, and presence of ionophore and other plasma membrane modifying agents such as lanthanum appear to corroborate this hypothesis.

Animals↗

PubMed1986

Hyperthermia inhibition of tumor cells growth in the presence of ruthenium red.

Ruthenium red (RR) is taken up by DS sarcoma cells as a linear function of its concentration. Higher temperatures produce a higher uptake. This increased uptake is coincident with an augmentation of Trypan blue inclusion. A diminution of calcium transport in the presence of RR is observed at hyperthermia, and its uptake is not linear but presents a plateau for all temperatures and concentrations. RR-cell membrane interaction seems to produce two different effects: an early blocking of calcium transport, and a later change of the physicochemical characteristics of the plasma membrane. On the colony forming ability of CA1 cell RR shows clearly an intrinsic toxic effect, and when present during hyperthermia a low but significant enhancement of tumor cells mortality.

Animals↗

PubMed1986

Calcium and ATPase activity during hepatic intoxication with thioacetamide.

The effects of acute thioacetamide (TAA) intoxication on the calcium, magnesium, sodium and potassium content of liver and on its ATPase activities were studied in rats. Samples of liver were analyzed by atomic absorption spectrometry for their cationic content 6, 24 and 48 h after administration of TAA through a stomach tube. After sonification other samples were assayed for (Na+ + K+)-dependent, (Ca2+ + Mg2+)- and Ca2+-dependent ATPases. No apparent correlation has been found between the increased hepatic calcium after TAA treatment and the variations of ATPase activity. Both calcium movement and ATPase activity appear sex-determined. These results bring support to the hypothesis that an interaction between TAA or its metabolites with the cell membrane provokes an increased influx of extracellular calcium. The relationship between this calcium increase and the changes in ATPase activity with the events triggering the neoplastic transformation is discussed.

Acetamides↗

PubMed1985

Enhancement of hematoporphyrin derivative uptake in vitro and in vivo by tumor cells in the presence of lanthanum.

Hematoporphyrin derivative is currently used as a photochemotherapeutic agent in the treatment of neoplasms. The uptake of hematoporphyrin derivative was determined in vitro and as a function of time with Ehrlich ascites cells in the presence of lanthanum and in vivo with VFM1, tumor-bearing mice pretreated by intratumoral injection of LaCl3. Our results indicate that the treatment with lanthanum increases the uptake of hematoporphyrin derivative by tumor cells.

Animals↗

PubMed1985

Placenta, embryo, and tumor uptake of 67Ga-citrate and 59Fe-citrate.

The uptake of gallium citrate Ga67 and ferrous citrate Fe59 was studied in pregnant rats with or without a 4-dimethylamino-stilben(DS)-induced sarcoma tumor. The liver and placenta of the mother concentrated 67Ga, while the uptake of 67Ga in the embryo was minimal. However, the embryo showed higher concentrations of 59Fe. Preloading with iron did not affect the 67Ga uptake of the placenta, but increased the uptake in the blood and liver of the mother. With regard to 59Fe uptake, iron loading only affected the embryo liver. Tumors and the placenta showed a similar 67Ga uptake but a different incorporation of 59Fe. The probable mechanisms involved are discussed.

Animals↗

PubMed1985

Molecular structures involved in 67Ga and 59Fe binding by placenta and tumors.

The binding of 67Ga and 59Fe by placenta and tumors was compared. After sonification, about 50% of the total radioactivity was present in the insoluble fraction consisting of heavy subcellular particles (mitochondria, fragments of membranes, nuclei, etc.) and known to be rich in lipo- and glycoproteins. Heat denaturation and gel filtration were used to study transferrin and ferritin distribution in the supernatant. The differences between 59Fe and 67Ga uptake in this supernatant seemed to indicate that the transferrin-ferritin system plays a less important role in 67Ga binding than in 59Fe binding.

Animals↗

PubMed1985

Effects of extracellular calcium on calcium transport during hyperthermia of tumor cells.

The effects of different concentrations of extracellular ion calcium on the transport of calcium by tumor cells have been studied by means of the uptake of radiocalcium. Tumor cells incubated at 45 degrees C take up 4-10 times the amount of radioactivity incorporated by cells incubated at 37 degrees C. The difference is still greater (up to 100 times) for the intracellular incorporation as assessed by elimination of the membrane-bound calcium by EGTA treatment. The possible mechanisms involved in this differential behavior are discussed.

Animals↗