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M J DeStefano

Publications and source records attributed to M J DeStefano.

8 recordsLinked to original sources
PubMed1980

Effect of antitubulins on spontaneous and chemotactic migration of neutrophils under agarose.

The effect of colchicine, Nocodazole or vinblastine on the movement of mouse bone marrow neutrophils was examined by the method of migration under agarose. Migration was estimated by counts of the numbers of cells that left the wells and moved under the gel. Micromolar concentrations of the agents increased spontaneous migration 2- to 4-fold, while lumicolchicine was ineffective. The increase may be due to the disassembly of the microtubular skeleton, making the cells more fluid, or to some other effect of the drugs. Since other agents, such as serum, low osmolality and low pH also enhance migration, these were tried in combination with a pretreatment of the cells with colchicine. Serum and colchicine acted synergistically, low osmolality and colchicine were additive. Possible, the enhancement of neutrophil migration by serum or lowered osmolality does not require intact microtubules. At low pH, colchicine had very little stimulatory effect, perhaps indicating that the microtubules are more colchicine-resistant at low pH. Although antibular drugs showed such marked effects on spontaneous migration, the chemotactic attraction of the neutrophils towards activated serum was unaffected. This indicates that the sensory and control mechanisms of the cells are resistant to antibulins.

Animals↗
PubMed1976

Cell shape changes induced by cationic anesthetics.

The effects of local anesthetics on cultivated macrophages were studied in living preparations and recorded in still pictures and time-lapse cine-micrographs. Exposure to 12mM lidocaine or 1.5 mM tetracaine resulted in rounding in 10-15 min. Rounding was characterized by cell contraction, marked increase in retraction fibrils, withdrawal of cell processes, and, in late stages, pulsation-like activity and zeiosis. Cells showed appreciable membrane activity as they rounded. Respreading was complete within 15 min of perfusion in drug-free medium and entailed a marked increase in surface motility over control periods. As many as eight successive cycles of rounding and spreading were obtained with lidocaine without evidence of cell damage. The effects of anesthetics were similar to those observed with EDTA, but ethylene-glycol-bis(beta-aminoethylether)-N, N'-tetraacetic acid-Mg was ineffective. Rounding was also induced by benzocaine, an anesthetic nearly uncharged at pH 7.0. Quaternary (nondischargeable) compounds were of low activity, presumably because they are slow permeants. Lidocaine induced rounding at 10 degrees C and above but was less effective at 5 degrees C and ineffective at 0 degrees C. Rounding by the anesthetic was also obtained in media depleted or Na or enriched with 10 mM Ca or Mg. The latter finding, together with the failure of tetrodotoxin to induce rounding, suggests that the anesthetic effect is unrelated to inhibition of sodium conductance. It is possible that the drugs influence divalent ion fluxes or some component of the contractile cells' machinery, but a metabolic target of action cannot yet be excluded.

Anesthetics, Local↗
PubMed1973

Manganese stimulates adhesion and spreading of mouse sarcoma I ascites cells.

Adhesion of Sarcoma I cells (SaI) to untreated or to serum-treated glass was examined by layering (51)Cr-labeled cells on the substrate for 20 min at 34 degrees C and determining the glass-bound radioactivity after the monolayers were rinsed. Adhesion to untreated glass proceeded in sodium chloride-imidazole-potassium medium (SIK) without added divalent cations, whereas SaI adhered maximally to the serum-coated substrate only in the presence of 50 microM or more Mn. Divalent Mg, Ca, Co, Ni, or Zn were inactive or minimally active. Mn-stimulated adhesion was sharply temperature dependent, reversible upon removal of Mn, and inhibited by Ca as well as by cytochalasin B, vinblastine, or tetracaine. Adhesion of SaI in SIK did not ensue when cells or the coated substrate were pretreated with Mn and washed in SIK before the adhesion assays. Microscope observations showed that Mn induced the formation of cell processes, ruffles, and veils, and that SaI spread on the uncoated or serum-coated substrate when exposed to Mn. Cells withdrew veils and processes and rounded up when postincubated in Mn-free medium. Formation of cell processes and spreading was inhibited by cytochalasin B, vinblastine, or tetracaine. Manganese-induced adhesion seems to require the participation of microtubules and microfilaments and may be mediated by an effect of Mn on Ca fluxes. The results support the role of cell processes and spreading in cell-to-substrate adhesion.

Animals↗
PubMedDate not supplied

Use of the local anesthetic lidocaine for cell harvesting and subcultivation.

Cell suspensions from monolayer cultures of 3T3, SV-3T3, BHK, BS-C-1, or macrophages, were prepared by brief exposure of the cultures to the amide anesthetic lidocaine. Cells were subcultivated six times without marked impairment of plating efficiency. The method should be applicable to physiological, biochemical, or immunological studies in which exposure of cells to proteolytic enzymes is to be avoided.

Blood↗