scholarly journals Isolated Epithelial Cells of the Toad Bladder

1968 ◽  
Vol 51 (6) ◽  
pp. 770-784 ◽  
Author(s):  
J. T. Gatzy ◽  
W. O. Berndt
Keyword(s):  
Epithelial Cells ◽  
Connective Tissue ◽  
Divalent Cation ◽  
Toad Bladder ◽  
Trypsin Treatment ◽  
Na Transport ◽  
Isolated Cells ◽  
General Increase ◽  
High Sucrose ◽  
Isolated Cell

Epithelial cells of the toad bladder were disaggregated with EDTA, trypsin, hyaluronidase, or collagenase and were then scraped free of the underlying connective tissue. In most experiments EDTA was complexed with a divalent cation before the tissue was scraped. QOO2, sucrose and inulin spaces, and electrolytes of the isolated cells were measured. Cells disaggregated by collagenase or hyaluronidase consumed O2 at a rate of 4 µl hr-1 dry wt-1. QOO2 was increased 50% by ADH (100 U/liter) or by cyclic 3',5'-AMP (10 mM/liter). Na+-free Ringer's depressed the QOO2 by 40%. The QOO2 of cells prepared by trypsin treatment or by two EDTA methods was depressed by Na+-free Ringer's but was stimulated relatively little by ADH. Two other EDTA protocols produced cells that did not respond to Na+ lack or ADH. The intracellular Na+ and K+ concentrations of collagenase-disaggregated cells were 32 and 117 mEq/kg cell H2O, respectively. Cation concentrations of hyaluronidase cells were similar, but cells that did not respond to ADH had higher intracellular Na+ concentrations. Cells unresponsive to ADH and Na+ lack had high sucrose spaces and low transcellular membrane gradients of Na+, K+, and Cl-. The results suggest that trypsin and EDTA disaggregation damage the active Na+ transport system of the isolated cell. Certain EDTA techniques may also produce a general increase in permeability. Collagenase and hyaluronidase cells appear to function normally.

Isolation of epithelial cells from toad bladder

1980 ◽  
Vol 238 (2) ◽  
pp. F140-F149
Author(s):  
H. J. Rodriguez ◽  
D. W. Scholer ◽  
M. L. Purkerson ◽  
S. Klahr
Keyword(s):  
Epithelial Cells ◽  
Cyclic Nucleotides ◽  
Ethylenediaminetetraacetic Acid ◽  
Mechanical Damage ◽  
Toad Bladder ◽  
Amino Acid Incorporation ◽  
Isolated Cells ◽  
Collagenase Treatment ◽  
Acid Incorporation ◽  
Epithelial Sheets

The epithelial cells of the toad bladder have been isolated by brief exposure to ethylenediaminetetraacetic acid followed by treatment with collagenase, DNAse, and the application of shearing forces. This approach eliminates the need for scraping of the mucosal surface and reduces mechanical damage during harvesting of the epithelium. The method yields intact, isolated epithelial cells and few clumps. The three major types of epithelial cells described in the intact toad bladder were present in the final preparation. The cellular contents of nucleic acids and proteins (in pg/cell) were: DNA 22.5 +/- 1.1; RNA, 12.9 +/- 0.6; and protein, 192 +/- 9. The isolated cells possess rates of oxygen consumption and amino acid incorporation higher than those of epithelial sheets obtained by collagenase treatment and scraping of the intact bladder. However, the production of cyclic nucleotides in response to stimulation by vasopressin and carbachol is comparable in both preparations.

scholarly journals K Fluxes in Frog Skin

1965 ◽  
Vol 48 (6) ◽  
pp. 1011-1033 ◽  
Author(s):  
Peter F. Curran ◽  
Marcelino Cereijido
Keyword(s):  
Epithelial Cells ◽  
Connective Tissue ◽  
Active Transport ◽  
Time Constant ◽  
Frog Skin ◽  
Bathing Solution ◽  
Na Transport ◽  
K Uptake ◽  
Low Concentrations ◽  
K Concentration

A method has been developed for measuring K influx into the epithelial cells of frog skin from the inside solution. Diffusion delay in the connective tissue has been taken into account. Ninety-four per cent of skin K was found to exchange with K42 in the inside solution with a single time constant. K influx showed saturation with increasing K concentration, was not altered by imposing a potential difference of ±200 mv across the skin, and was inhibited by dinitrophenol, fluoroacetate, and ouabain. Relatively low concentrations of dinitrophenol (5 x 10-5 M) and fluoroacetate (10-10 M) had no effect on k influx but caused a 40 per cent decrease in net Na flux. There was no correlation between the rate of K uptake at the "inner barrier" and the rate of net Na transport. Reduction of net Na transport by lowering Na concentration in the outside solution caused little change in K uptake. These observations indicate that there is not a significant Na-K exchange involved in active transport of Na across the skin. K influx was found, however, to require Na in the inside bathing solution.

Factors Involved In the Plasminogen Activation System in Human Breast Tumours

1994 ◽  
Vol 71 (05) ◽  
pp. 684-691 ◽  
Author(s):  
László Damjanovich ◽  
Csaba Turzó ◽  
Róza Ádány
Keyword(s):  
Epithelial Cells ◽  
Connective Tissue ◽  
Plasminogen Activators ◽  
Breast Tumour ◽  
Plasminogen Activation ◽  
Malignant Tumours ◽  
Plasminogen Activation System ◽  
Activation System ◽  
Malignant Breast ◽  
Pai 1

SummaryThe plasminogen activation system is a delicately balanced assembly of enzymes which seems to have primary influence on tumour progression. The conversion of plasminogen into serine protease plasmin with fibrinolytic activity depends on the actual balance between plasminogen activators (urokinase type; u-PA and tissue type; t-PA) and their inhibitors (type 1 and 2 plasminogen activator inhibitors; PAI-1 and PAI-2). The purpose of this study was to determine the exact histological localization of all the major factors involved in plasminogen activation, and activation inhibition (plasmin system) in benign and malignant breast tumour samples. Our results show that factors of the plasmin system are present both in benign and malignant tumours. Cancer cells strongly labelled for both u-PA and t-PA, but epithelial cells of fibroadenoma samples were also stained for plasminogen activators at least as intensively as tumour cells in cancerous tissues. In fibroadenomas, all the epithelial cells were labelled for PAM. Staining became sporadic in malignant tumours, cells located at the periphery of tumour cell clusters regularly did not show reaction for PAI-1. In the benign tumour samples the perialveolar connective tissue stroma contained a lot of PAI-1 positive cells, showing characteristics of fibroblasts; but their number was strongly decreased in the stroma of malignant tumours. These findings indicate that the higher level of u-PA antigen, detected in malignant breast tumour samples by biochemical techniques, does not necessarily indicate increased u-PA production by tumour cells but it might be owing to the increased number of cells producing u-PA as well. In malignant tumours PAI-1 seems to be decreased in the frontage of malignant cell invasion; i.e. malignant cells at the host/tumour interface do not express PAI-1 in morphologically detectable quantity and in the peritumoural connective tissue the number of fibroblasts containing PAI-1 is also decreased.

scholarly journals Effects of butyrate on histone deacetylation and aldosterone-dependent Na+ transport in the toad bladder.

1983 ◽  
Vol 258 (5) ◽  
pp. 3388-3395
Author(s):  
A Truscello ◽  
K Geering ◽  
H P Gäggeler ◽  
B C Rossier
Keyword(s):  
Histone Deacetylation ◽  
Toad Bladder ◽  
Na Transport

Contact behaviour during the reassociation of dissociated epithelial cells in primary culture

1987 ◽  
Vol 88 (4) ◽  
pp. 521-526
Author(s):  
R.M. Brown ◽  
C.A. Middleton
Keyword(s):  
Epithelial Cells ◽  
Chick Embryo ◽  
Primary Culture ◽  
Cell Cultures ◽  
Corneal Epithelium ◽  
Time Lapse ◽  
Cell Types ◽  
Epidermal Cells ◽  
Isolated Cells ◽  
Contact Behaviour

The behaviour in culture of dissociated epithelial cells from chick embryo pigmented retina epithelium (PRE), corneal epithelium (CE) and epidermis has been studied using time-lapse cinematography. The analysis concentrated on the contact behaviour of 60 previously isolated cells of each type during a 24 h period starting 3.5 h after the cells were plated out. During the period analysed the number of isolated cells in cultures of all three types gradually decreased as they became incorporated into islands and sheets of cells. However, there were significant differences in behaviour between the cell types during the establishment of these sheets and islands. In PRE cell cultures, islands of cells developed because, throughout the period of analysis, collisions involving previously isolated cells almost invariably resulted in the development of a stable contact. Once having established contact with another cell these cells rarely broke away again to become reisolated. In contrast the contacts formed between colliding CE and epidermal cells were, at least initially, much less stable and cells of both these types were frequently seen to break away and become reisolated after colliding with other cells. Sheets and islands of cells eventually developed in these cultures because the frequency with which isolated cells become reisolated decreased with increasing time in culture. The possible reasons underlying the different behaviour of PRE cells, when compared with that of CE and epidermal cells, are discussed. It is suggested that the decreasing tendency of isolated CE and epidermal cells to become reisolated may be related to the formation of desmosomes.

THE EFFECT OF VALINOMYCIN ON THE TOAD BLADDER: ANTAGONISM TO VASOPRESSIN AND ALDOSTERONE

1969 ◽  
Vol 45 (2) ◽  
pp. 287-295 ◽  
Author(s):  
P. J. BENTLEY
Keyword(s):  
Macrolide Antibiotic ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Water Transfer ◽  
Toad Bladder ◽  
Na Transport ◽  
Bathing Medium ◽  
Sodium Transfer ◽  
Sites Of Action ◽  
Subsequent Addition

SUMMARY The macrolide antibiotic valinomycin decreased short-circuit current (SCC, Na transport) across the isolated bladder of the toad. This effect was not overcome by increasing the K+ levels in the bathing medium or by the action of amphotericin B. The effects of vasopressin on both sodium and water transfer across the toad bladder were inhibited by valinomycin and the latter inhibition is non-competitive. The action of theophylline in increasing water transfer across the bladder was also inhibited. Cyclic AMP also increased water and Na+ transfer across the bladder but its action was not reduced by the macrolide. These results suggest that valinomycin inhibits adenyl cyclase. Aldosterone increases sodium transport across the toad bladder and this action was abolished by previous incubation of the tissue with the macrolide. Once the steroid-induced effect had been established subsequent addition of valinomycin did not alter the sodium transfer. Valinomycin thus appears to have several sites of action on the toad bladder.

Sign in / Sign up

Export Citation Format

Share Document