Evidence for changes in cell shape from a 2-dimensional to a 3-dimensional substrate

Summary Chick embryo mesoderm cells were explanted to culture systems in vivo and in vitro and their subsequent movements were correlated with the external morphology as studied by SEM. In vitro cell movements are exaggerations of normal in vivo movements where a 2-dimensional substrate is encountered rather than a 3-dimensional environment.The authors are grateful to Mr J. Smith and Mrs S. Bulman who provided excellent technical assistance and to Mr G. L. C. McTurk who skillfully produced the scanning electron micrographs in the Leicester University Scanning Electron Microscope Unit.     

A cell culture substrate obtained from heat-fused collagen.

Coverslips coated with rat-tail collagen dried at 37 degrees C were placed in a hot-air sterilizing oven at 160 degrees C for 2 h. The resulting transparent sterile film was found to be a useful multipurpose substrate for cell culture and for subsequent histological sectioning.     

Viscosity changes in a polymerized substrate due to the action of a hydrolytically depolymerizing enzyme

Zusammenfassung Nachweis einer Enzymbildung nach Azotobacter-Infektion durch Phagen mit Spezifität für Kapsel-Depolymerisierung. Das Verfahren erfasst die Enzymaktivität durch Registrierung der graduellen Veränderung der Viskosität des sich vorbereitenden Kapselstoffes.

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Supported USPH Grant A102830.     

Evidence for a role of IFN gamma in control of Listeria monocytogenes in T cell deficient mice.

The role of interferon (IFN) gamma in controlling chronic infections of Listeria monocytogenes (Listeria) was studied in athymic C57BL/6 nu/nu mice, and by treating thymectomized C57BL/6 +/+ mice with monoclonal rat CD4 and CD8-specific monoclonal antibodies (Mab). Mice treated with a combination of the two T cell subset antibodies were similar to athymic, nude mice in being able to control Listeria infection, keeping the titers below 3-5 log10 bacteria per organ, but they could not eliminate them completely. Treatment with antibodies to IFN gamma of nude or CD4+ + CD8+ - T cell-depleted mice suffering from chronic Listeria infection caused a marked increase of Listeria titers in liver and spleen. This result implies a role of IFN gamma in maintaining anti-Listeria resistance in mice lacking mature T cells.     

Evidence for a neurological zoom system in vision from angular changes in some receptive fields of single neurons with changes in fixation distance in the human visual cortex

Résumé Dans le cortex visuel humain de 3 champs réceptifs de neurones individuels 2 présentent des changements d'angle correspondant aux changements de perception à distance. Ces changements peuvent être la base neurologique du système perceptif de stabilité, de «zoom» ou de graduation de la vision.     

Nuclear envelope changes related to cell activation inHelianthus tuberosus L.

Summary The ultrastructure of nuclei from dormant and activatedHelianthus tuberosus tuber cells has been investigated with particular reference to nuclear pore frequency and nuclear envelope invaginations, and the results discussed in relation to observations made on other cell types.     

Evidence for early anoxic-ischaemic cell damage in the rat brain

Zusammenfassung Es wird gezeigt, dass Schädigungen von Nervenzellen nach dem Aussetzen in eine Stickstoffatmosphäre, mit oder ohne Abklemmung der Carotis, histologisch erkennbare Veränderungen ergeben.     

Penicillamine induced changes in growing rats. II. liver parenchymal cell

Zusammenfassung d-Penicillamin als Kupferchelator bewirkt im Langzeitversuch eine isolierte Veränderung der stereologischen Parameter der Mitochondrien und der «microbodies». Zusammenhänge mit der Aktivitätshemmung kupferhaltiger Oxydasen in den beiden Zellorganellen werden vermutet.     

Evidence for synergism in steroid hormone-receptor association.

A number of glucocorticoids stimulated oestradiol binding to liver cytosol receptor; oestradiol activated glucocorticoid receptor association at a time when it reversed triamcinolone mediated increase in liver glycogen synthesis.     

2-Methoxybenzoyl phosphate: a new substrate for continuous fluorimetric and spectrophotometric acyl phosphatase assays

A new aromatic acyl phosphate, 2-methoxybenzoyl phosphate, has been synthesized. The compound shows an intrinsic fluorescence; it displays an intense emission band at 390 nm upon excitation in the near UV region. This band practically disappears after hydrolysis of the product. On the other hand, the product displays differences in the near UV absorption spectra measured before and after hydrolysis. The at 301 nm is 2720 M^–1 cm^–1, a value that is 4.3-fold higher than that of benzoyl phosphate (the usual substrate for acylphosphatase assay) at 283 nm. The main kinetic parameters of three different acylphosphatase molecular forms (the muscular isoenzyme and two subtypes of the organ common isoenzyme) were determined using both benzoyl phosphate and 2-methoxybenzoyl phosphate as substrates, and then compared. These kinetic data and the UV absorption and fluorescence properties of 2-methoxybenzoyl phosphate sugest that this compound has better substrate features than benzoyl phosphate, and can be used for both high sensitivity continuous fluorimetric and UV absorption spectrophotometric assays of acylphosphatase.     

Evidence of a direct action of triiodothyronine (T3) on the cell membrane of GH3 cells: an electrophysiological approach

Summary Electrophysiological experiments demonstrate that triiodothyronine (T₃) exerts a direct effect on the membrane of a strain of cultured rat pituitary tumor cells, GH₃/B₆. These cells respond to pressure application of T₃ (2–5 nl, concentration 1·10^–10 M) with an increase in the membrane resistance (R_m) and a hyperpolarization. Spontaneously firing cells become silent.     

Evidence of a direct action of triiodothyronine (T3) on the cell membrane of GH3 cells: an electrophysiological approach

Electrophysiological experiments demonstrate that triiodothyronine (T3) exerts a direct effect on the membrane of a strain of cultured rat pituitary tumor cells, GH3/B6. These cells respond to pressure application of T3 (2-5 nl, concentration 1 X 10(-10) M) with an increase in the membrane resistance (Rm) and a hyperpolarization. Spontaneously firing cells become silent.     

Evidence for a hypocalcemic factor in the hypothalamus

Zusammenfassung Es konnte gezeigt werden, dass ein Hypothalamus-Extrakt von Meerschweinchen an hypophysektomierten Raten eine deutliche Senkung des Plasmakalziums bewirkte.