Use of aggregating cell cultures for toxicological studies

Summary Relatively simple techniques are now available which allow the preparation of large quantities of highly reproducible aggregate cultures from fetal rat brain or liver cells, and to grow them in a chemically defined medium. Since these cultures exhibit extensive histotypic cellular reorganization and maturation, they offer unique possibilities for developmental studies. Therefore, the purpose of the present study was to investigate the usefulness of these cultures in developmental toxicology. Aggregating brain cell cultures were exposed at different developmental stages to model drugs (i.e., antimitotic, neurotoxic, and teratogenic agents) and assayed for their responsiveness by measuring a set of biochemical parameters (i.e., total protein and DNA content, cell type-specific enzyme activities) which permit a monitoring of cellular growth and maturation. It was found that each test compound elicited a distinct, dose-dependent response pattern, which may ultimately serve to screen and classify toxic drugs by using mechanistic criteria. In addition, it could be shown that aggregating liver cell cultures are capable of toxic drug activation, and that they can be used in co-culture with brain cell aggregates, providing a potential model for complementary toxicological and metabolic studies.     

A rapid microtechnique for incorporation studies in cell cultures

Zusammenfassung Eine Methode zur bequemen Messung radioaktiver Vorläufer in Monolayer-Zellkulturen wird beschrieben. Die auf flexiblen Plastikkulturplatten (z. B. Linbro FB 48-TC) in zahlreichen Einzelkulturen gezüchteten, markierten, extrahierten und getrockneten Monolayer-Kulturen können direkt (beispielsweise mit einer Schere) in Zählgläschen für die Szintillations-messung eingeschnitten werden.     

GFA expression in aggregating cultures of rat C6 glioma

Summary Few C6 glioma cells synthesize the astroglia-specific GFA protein in monolayer culture. A uniform population of GFA-positive cells was obtained by aggregating C6 cells in suspension culture, as previously reported for C6 glioma maintained on sponge foam matrices. These results strongly suggest that cell-to-cell interactions promote GFA expression.Acknowledgments. This work was supported by USPHS grant No. 13034 and by the Veterans Administration.     

Tailored substrates for studies of attached cell culture

Substrates for studies of the interactions of attached cells with extracellular matrix components are often prepared by allowing a protein to adsorb from solution onto a glass or polystyrene substrate. This method is simple and effective for many studies, but it can fail in cases that require rigorous control over the structure and composition of adsorbed protein. Self-assembled monolayers formed by the spontaneous ordering of terminally functionalized alkanethiols onto a gold substrate are a class of well-ordered substrates and provide a convenient method for tailoring substrates with ligands, proteins and other groups. Methods that can pattern the monolayers provide a general strategy to create substrates that control the size, shape and spacing of attached cells. This review illustrates recent work that has used these methods of surface chemistry to create tailored substrates for studies in cell biology. Received 14 November 1997; received after revision 10 March 1998; accepted 10 March 1998     

A study of irrigation fluids for neurosurgery on brain primary cell cultures

Summary Primary cell cultures from newborn rat brain hemispheres were exposed to different irrigation fluids used in neurosurgery. The cells died after incubation for 5 min with hydrogen peroxide, and the number of cells was drastically decreased after 10 sec of incubation. They shrank after incubation in Elliott's artificial cerebrospinal fluid for 3 h, but the viability as determined by trypan blue exclusion test was not affected. Physiological sodium chloride, Ringer's solution and the culture medium 199 with Hank's salt had no noticeable effect on the viability or morphology of the cells.Acknowledgments. This study was supported by grants from the Medical Faculty of Göteborg and from Statens Naturvetenskapliga Forskningsråd. We want to thank Dr Åke Sellström and Dr Hans-Arne Hansson for valuable discussions.     

Inhibition of cell division in mammalian cell cultures by hypertonic medium

Résumé L'arrêt de la métaphase se produit dans les cellules de HeLa S-3 au contact d'un milieu de tonicité accrue (>165 mM). L'accumulation optimale intervient à 277 mM lorsque du NaCl a été utilisé pour augmenter l'influence du milieu. Les effets de l'usage d'autres sels et d'autres types de cellules sont décrits. La dilution du milieu à 165 mM donne lieu à un arrêt synchrone du processus de la mitose dans les cellules et assure la conservation d'un bon synchronisme au cours de la division cellulaire suivante.     

Molecular weight of virus-induced tortoise interferon in cell cultures

Zusammenfassung Das Molekulargewicht des Interferons, durch Selmiki Forest Virus in Zellkulturen von Schildkrötenniere induziert, wurde mittel Gelchromatographie mit Sephadex G-100 bestimmt und es ergab sich ein Wert von 33,500.     

Preliminary studies on mouse macrophage cultures infected with trachoma agents

Riassunto L'infezione di culture in vitro di macrofagi di topo con due diversi ceppi di agente del tracoma, determina la comparsa di tipiche inclusioni intracitoplasmatiche, e, in seguito, di lisi cellulare. Lo sviluppo delle inclusioni è stato studiato a tempi diversi dall'infezione. Sulla base dell'osservazione morfologica, si suppone che l'agente del tracoma possa moltiplicarsi in tali culture cellulari, determinando un secondo ciclo di infezione.     

Destruction of the platelet aggregating activity of ristocetin A

Hydrolysis of ristocetin A in 0.1 N HCl at 37 degrees C for 2 h resulted in the loss of its ability to induce platelet aggregation in platelet-rich plasma derived from guinea-pigs and humans. However its antibiotic activity against Staph. aureus was not lost.     

Destruction of the platelet aggregating activity of ristocetin A

Summary Hydrolysis of ristocetin A in 0.1 N HCl at 37°C for 2 h resulted in the loss of its ability to induce platelet aggregation in platelet-rich plasma derived from guinea-pigs and humans. However its antibiotic activity againstStaph. aureus was not lost.This work was supported, in part, by a contract from the National Heart, Lung, and Blood Institute (USPHS).     

Toxicity of rabbit anti-dog lymphocyte serum to human cell cultures

Zusammenfassung Die Kombination von Kaninchen Anti-Hund Lymphozytenserum und Kaninchen Komplement war für menschliche Blutzellen in in-vitro-Kultur sowie für. Blutlymphozyten von Patienten mit chronischer lymphatischer Leukämie toxisch.     

Adenylate cyclase activation by trypsin in KB cell cultures

Summary Trypsin commonly used for cell dispersion increases adenylate cyclase activity of KB cells. It acts on catalytic receptors, since the apparent K_m for ATP is lowered, and it alters the dependence of adenylate cyclase on Mg⁺⁺ ions.     

Regulation of lymphokine production in peripheral blood mononuclear cell cultures

Summary An increase in the production of macrophage migration inhibitory factor, chemotactic factor for neutrophils, and skin reactive factor, was observed in lymphocyte cultures if the cells were allowed to age in culture for 24 h. The increased lymphokine production was reduced by adding concanavalin A-stimulated and mitomycin C-treated suppressor cells. It is suggested that the lymphokine production could be regulated by suppressive mononuclear cells.This work was supported by the Scientific Research Council, Ministry of Health, Hungary (Code No. 421 0304011/S).