Erythrophagocytosis by cultured skin fibroblasts from patients with hereditary metabolic disorders.

Phagocytosis of native allogenic red blood cells was observed in cultures of skin fibroblasts obtained from patients with neuronal ceroid-lipofuscinosis, Niemann-Pick disease type C and morbus Fabry. Occasional phagocytizing cells were observed in 9 other syndromes. Cells from three normal donors did not phagocytize.

Binding of (125I) triiodothyronine to human peripheral leukocytes and its internalization.

Ultrastructural autoradiography showed high specific binding of (125I) triiodothyronine, as confirmed by a competition test, to plasma membranes, nuclei and mitochondria of human peripheral leukocytes. A high level of binding was also noted on the granulocytes' granules, especially in eosinophils.

Internalization of triiodothyronine-bovine serum albumin-colloidal gold complexes in human peripheral leukocytes.

Complexes of triiodothyronine-bovine serum albumin-colloidal gold were specifically internalized in human peripheral leukocytes after 5 min of incubation. The specificity was partially lost after a longer incubation.

Relation between high-frequency electrical impedance and malignity of two L cell sublines.

Two L cell sublines (L-As and LC3), differing in the ability to induce sarcomas in irradiated C3H mice, were grown on special gold electrodes interrupted in the middle by a 50 micron wide slot. Electrical impedance of the two sublines was compared at 100 kHz in a special measuring device connected with an apparatus used for impedance measurement in clinics. Significantly lower values of impedance characterized the LC3 cells, which induced more sarcomas in susceptibility hosts than the L-As cells. This result agrees with the findings in human tumors compared with corresponding normal tissue or benign growth, and stresses the importance of the cell population as such in impedance measurements.

Myotube-like structures in cultures of rat liver cells.

Branching and budding myotube-like structures developed in primary cultures of rat liver cells and in the JH1 cell line derived from them. Elongated uninuclear cells aligned in chains and fused into multinuclear tubes of varying length and thickness. The tubes contained thick and thin filaments running in all directions. The filaments were occasionally linked with M lines and formed incomplete hexagonal patterns resembling those of skeletal muscle myofilaments, but a regular arrangement of the filaments and organelles was lacking. Cross-striation and contractions were never observed. Both uninuclear cells and multinuclear tubes contained numerous lysosomes, myelin figures and lamellated bodies as well as electronlucent or content-filled vacuoles and cisternae of variable size, sometimes reminding the sarcoplasmic reticulum in early stages of its development. Endocytotic caveolae and vesicles were present in all elements. These features together with interdigitated cell processes and specialized cell contacts suggested a possible relationship of the cells to the reticuloendothelial system.

Prolonged culture of cells from normal human thyroid tissue and toxic goiters.

Normal human thyroid cells and cells from patients with Grave's disease were cultured for 5 months (11 passages) in vitro. Both normal and diseased thyreocytes, similar in morphology, proliferated actively and responded to thyrotropin stimulation by cytoplasmic arborization of a part of the population. Slight inhibition of mitotic activity was present under the influence of thyrotropin.

Mitogenic effect of the serum of rats exposed to cold.

Serum from rats exposed for 3 days to 5 degrees C stimulated the multiplication of mouse heteroploid and human and rat diploid cells in culture. The response of the cells to this unspecific growth stimulation was related to the growth capacities of the different cell types.

Daughter cell fusion and formation of polykaryons in a cold-resistant (CR) L cell variant.

A cold-resistant (cr) variant of mouse L fibroblasts called LC3, isolated by repeated cooling of the parent population for several weeks at 4 degrees C, differed from the wild-type cells in morphology and function. Microcinematographic records demonstrate that their motility is markedly reduced when compared with that of the L cells. They enter mitosis at 30 degrees C, at 37 degrees C and at 39 degrees C, but they finish cytodieresis only at 30 degrees C. At the higher temperatures, they reach anaphase, but then the daughter cells fuse and form polykaryons. At 39 degrees C, bizarre forms with large undulating membranes predominate in the damaged population. The cr cells may be used as a model for the study of temperature adaptations on cellular level, as well as for the analysis of the relations between membrane properties, cold resistance and cell cycle control.

Potassium uptake by cold-resistant mouse L cells stored at low temperature.

Adaptation of a cultured mouse L cell population to 4 degrees C increased the survival of the cells and induced the uptake of potassium from the medium at this temperature.

Isolation and properties of LC3 cells, a new cold-resistant L cell subline.

LC3 cells, selected from the L-As cells by repeated exposures to 4 degrees C for 3--6 weeks with intermittent reincubations at 36 degrees C, differ from the initial population by better survival at 4 degrees C, more rapid recovery at 36 degrees C, a higher multiplication at subnormal temperature, a higher sensitivity to supranormal temperature, increased cell size at 36 degrees and 4 degrees C, and higher oxygen consumption at 36 degrees C. These properties are the same as those described in our previously isolated cold-resistant L cell variants and are typical for the resistance to low temperature. The increased activity of alkaline phosphatase, detected in two of our cold-resistant L cell sublines, was not found in the LC3 cells and has thus no relation to decreased cold sensitivity.

Increased susceptibility to infection with herpes simplex virus types 1 and 2 of cold-adapted L cells.

L cells (L-As subline) have been adapted to a temperature of 4 degrees C. In the cold-adapted cells, designated LC3, greater amounts of infectious herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) were synthesized than in the original L-As cells or in another control L-cell line. Two strains of HSV-1 reached higher infectious titres in LC3 cells grown at 36 degrees C than in those grown at 32 degrees C. The HSV-2 strain tested replicated in LC-3 cells grown at 32 degrees C better than at higher temperature. Increased reproduction of HSV in LC3 cells was not due to enhanced adsorption of virions on the cells as compared with control L cells. The multiplication of cold-adapted LC3 cells was and was not more intensive than of L-As and control L cells, respectively. The virological results are confronted with known physiological properties of cold-adapted cells.

Enzymatic differences between short-lived and long-lived Drosophila strains.

The activities of acid and alkaline phosphatase were measured. The activity of acid phosphatase increased during the whole onto- genesis of both Drosophila strains studied--the short-lived vestigial and the long-lived white. This increase was more marked in the more rapidly ageing vestigial flies. The activity of alkaline phosphatase decreased in both strains of flies simultaneously from the larval stage to young imagos. A slight increase of the activity as in old vestigial as in adult white flies appeared.

Stimulation of DNA synthesis in rat liver and kidney by cold acclimation.

Exposure of adult Wistar female rats for 7 days to 4 degrees C leads to a marked increase in the weight of the liver and kidney, caused by an increased content of DNA and an increased number of cells in these organs. The weight as well as the DNA content of the cross-striated muscle do not change appreciably. Acclimation of the warmblooded rat to cold stimulates mitosis indirectly in cells capable of division, similarly as it stimulates directly the mitotic activity in mouse and human cells cultured and adapted to cold in vitro.