Biomedical subjects

L J Erkell

Publications and source records attributed to L J Erkell.

24 records · Page 2Linked to original sources

PubMed1975

Reversal of morphological differentiation of mouse neuroblastoma cells by mitosis-inhibitors and anesthetics.

Differentiated mouse neuroblastoma cells (C 1300) were exposed to various mitosis-inhibitors (vinblastine, colchicine and griseofulvin) and substances with anesthetic action (lidocaine, tetracaine, chlorpromazine and sodium dodecyl sulphate). All the drugs caused rapid retraction of the neurites, which was reversible in all cases but for sodium dodecyl sulphate, and showed a sigmoid dose-response relationship. The two groups of substances caused morphologically similar effects in that the microtubules disappeared and the intracellular orientation was lost. The order of potency of the anesthetics corresponded to their efficiency to cause nerve-block and antihemolysis as reported by others. Colchicine, griseofulvin, lidocaine and chlorpromazine were tested for effects of agglutination of undiffentiated cells. They inhibited agglutination at doses that were only slightly higher than those causing neurite retraction. The possibility of a close relationship between the cell membrane and microtubule system will be considered.

Animals↗

PubMedDate not supplied

Purity and transplantation properties of tumor cell suspensions.

Cell debris is inevitably produced by the mechanical and enzymatic procedures used to dissociate solid tumors. We investigated the influence of such debris on the i.v. and s.c. transplantability of B16 melanoma cells. Cell suspensions were centrifuged on a Percoll cushion to remove the debris, and the purified preparations were compared to untreated control suspensions. The i.v. injection of a massive dose (10(6) cells) of unpurified cells killed the animals within a few minutes, while the same amount of purified cells left the animals unaffected. When 5 X 10(5) cells were given, animals receiving purified cell suspensions had more extrapulmonary tumors at their time of death than those given unpurified cells. However, with a lower cell dose, 2 X 10(4) cells, there were no such differences in tumor incidence or distribution.

Animals↗

PubMedDate not supplied

Effects of RA 233 treatment on the adhesive, invasive and metastatic properties of 13762NF rat mammary tumor cells.

The pyrimido-pyrimidine analogue RA 233 has pleiotropic and differential effects on cultured tumor cell clones isolated from the 13762NF rat mammary adenocarcinoma. A nonresponsive clone of low metastatic potential (MTC) was not modified in its cell fragility or invasive, adhesive or lung-colonizing properties by RA 233 treatment. In contrast, a drug-responsive clone of high metastatic potential (MTLn3) was rendered less invasive and its cell fragility was decreased with RA 233 treatment, although its adhesiveness to lung microvascular endothelial cells and subendothelial matrix was unaffected by RA 233. Lung colonization of intravenously injected MTLn3 cells in syngeneic rats was significantly increased by RA 233 treatment, whereas spontaneous metastasis from the mammary fat pad to lung sites was decreased, although this decrease was not statistically significant.

Animals↗

PubMedDate not supplied

Photometric recording of cell viability using trypan blue in perfused cell cultures.

A perfusion system was developed to increase the reliability of cell viability estimations by continuous measurement of the uptake of trypan blue dye. Monolayer cell cultures were perfused with buffer containing toxic substances and trypan blue, and the staining of cells was continuously recorded at 591 nm in a spectrophotometer. Using mercuric chloride and methylmercuric chloride as test substances with C6 rat glioma cells, time- and dose-dependent increases in light absorbance were obtained over a 12h recording period. Methylmercuric chloride at 10(-6) M caused a half-maximal increase in relative absorbance in 4.5 h, whereas the corresponding time for mercuric chloride was 10.5 h.

Animals↗

PubMedDate not supplied

Radiation and hypothermia: changes in DNA supercoiling in human diploid fibroblasts.

The influence of hypothermia (2 degrees, 15 degrees and 28 degrees C) upon the effect of X-irradiation on chromatin from human diploid fibroblast cells (AG1518) was studied using the fluorescent halo assay. Rewinding of supercoils was inhibited in a dose-dependent manner when cells were irradiated with 4, 8 or 16 Gy. This inhibition of rewinding was reduced when cells were irradiated at subnormal temperatures compared with cells irradiated at 37 degrees C. One hour's preincubation at low temperature did not influence rewinding. When AG1518 cells were irradiated at 37 degrees C in the presence of the radical scavenger DMSO (0.5 M), the radiation-induced damage was reduced. No additional protection of DMSO in hypothermic cells (2 degrees C) was found, possibly indicating that OH-radical-mediated effects are more temperature dependent. These results are similar to those recently found for the malignant MCF-7 cell line.

Cold Temperature↗

PubMedDate not supplied

Effect of hypothermic irradiation of the growth characteristics of two human cell lines.

The effect of hypothermic irradiation on the growth characteristics of two human cell lines was investigated. Low temperature (2 degrees C) X-irradiation of MCF-7 cells (2, 3 and 4 Gy) resulted in higher surviving fractions compared to irradiation at 37 degrees C as assessed by the colony forming assay. The ratios for the surviving fraction between the two temperatures were 1.2, 1.5 and 1.7 at 2, 3 and 4 Gy, respectively. Correspondingly, the dose modifying factor was 1.23. The distribution of colony sizes (of those with more than 50 cells) was different with proportionally more small-sized colonies from cells irradiated at 2 degrees C. Colonies from diploid fibroblasts (HS27) were ill-defined and could not be counted. In conclusion, hypothermia during irradiation seems to influence the radioresponse in MCF-7 cells. The growth in multiwell plates of MCF-7 cells and human diploid fibroblasts (HS27) after irradiation with 3 and 4 Gy, respectively, at 2 degrees C or 37 degrees C was assessed by using the crystal violet growth assay. No difference between 2 degrees C or 37 degrees C irradiation was found for either of the two cell lines.

Adenocarcinoma↗