scholarly journals 7. DEVELOPMENT OF EPITHELIAL ELECTROLYTE TRANSPORT PROCESSES IN EARLY CHILDHOOD

1987 ◽  
Vol 22 (1) ◽  
pp. 97-97 ◽  
Author(s):  
H R Jenkins ◽  
T R Fenton ◽  
N I Mcintosh ◽  
M Dillon ◽  
P J Milla
Keyword(s):  
Early Childhood ◽  
Transport Processes ◽  
Electrolyte Transport

Ion Transport by the Cornea

Physiology ◽  
1988 ◽  
Vol 3 (3) ◽  
pp. 97-99
Author(s):  
M Wiederholt
Keyword(s):  
Ion Transport ◽  
Transport Processes ◽  
Electrolyte Transport

The cornea and lens of the eye are avascular transparent tissues that allow almost unimpeded transmission of light to the retina. The transparency of the cornea is a function of hydration, which in turn is affected by electrolyte transport processes across the cellular barriers.

Corticosteroid alteration of active electrolyte transport in rat distal colon

1983 ◽  
Vol 245 (5) ◽  
pp. G668-G675 ◽  
Author(s):  
E. S. Foster ◽  
T. W. Zimmerman ◽  
J. P. Hayslett ◽  
H. J. Binder
Keyword(s):  
Colonic Mucosa ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Transport Processes ◽  
Electrolyte Transport ◽  
Sodium Absorption ◽  
Rat Distal Colon ◽  
Potassium Absorption ◽  
Potassium Secretion

To determine the effect of corticosteroids on active transport processes, unidirectional fluxes of 22Na, 36Cl, and 42K were measured under short-circuit conditions across isolated stripped distal colonic mucosa of the rat in control, secondary hyperaldosterone, and dexamethasone-treated animals. In controls net sodium and chloride fluxes (JNanet and JClnet) and short-circuit current (Isc) were 6.6 +/- 2.2, 7.6 +/- 1.6, and 1.3 +/- 0.2 mu eq X h-1 X cm-2, respectively. Although aldosterone increased Isc to 7.3 +/- 0.5 mu eq X h-1 X cm-2, JNanet (6.9 +/- 0.7 mu eq X h-1 X cm-2) was not altered and JClnet was reduced to 0 compared with controls. Dexamethasone also stimulated Isc but did not inhibit JClnet. In Cl-free Ringer both aldosterone and dexamethasone produced significant and equal increases in JNanet and Isc. Theophylline abolished JNanet in control animals but not in the aldosterone group. Aldosterone reversed net potassium absorption (0.58 +/- 0.11 mu eq X h-1 X cm-2) to net potassium secretion (-0.94 +/- 0.08 mu eq X h-1 X cm-2). Dexamethasone reduced net potassium movement to 0 (-0.04 +/- 0.12 mu eq X h-1 X cm-2). These studies demonstrate that 1) corticosteroids stimulate electrogenic sodium absorption and 2) aldosterone, but not dexamethasone, inhibits neutral NaCl absorption and stimulates active potassium secretion. The effects of mineralocorticoids and glucocorticoids on electrolyte transport are not identical and may be mediated by separate and distinct mechanisms.

Gamma radiation affects active electrolyte transport by rabbit ileum: basal Na and Cl transport

1986 ◽  
Vol 250 (4) ◽  
pp. G540-G545 ◽  
Author(s):  
P. J. Gunter-Smith
Keyword(s):  
Gamma Radiation ◽  
Radiation Exposure ◽  
Short Circuit ◽  
Transport Processes ◽  
Electrolyte Transport ◽  
Electrolyte Imbalance ◽  
Whole Body ◽  
Cellular Transport ◽  
Rabbit Ileum

The effect of whole-body gamma radiation (5-12 Gy) on electrolyte transport by rabbit ileum in vitro was assessed for 1-96 h postirradiation using the short-circuit technique and radioisotopic fluxes. Although there was no effect of radiation on short-circuit current (Isc), transepithelial potential, or resistance 1 h after exposure, by 24 h the basal parameters of ileal segments isolated from irradiated animals were significantly greater than those of sham-irradiated controls. The Isc increased in a dose-dependent fashion and was greatest 24 h postexposure. Isotope flux experiments revealed that the increased Isc following irradiation resulted in part from a stimulation of active serosal-to-mucosal net Cl flux. There was no observable change in net Na transport. The results demonstrate that radiation exposure alters cellular transport processes, which may contribute to the fluid and electrolyte imbalance observed following radiation exposure.

scholarly journals Ion transport in the zebrafish kidney from a human disease angle: possibilities, considerations, and future perspectives

2017 ◽  
Vol 312 (1) ◽  
pp. F172-F189 ◽  
Author(s):  
Simone Kersten ◽  
Francisco J. Arjona
Keyword(s):  
Ion Transport ◽  
Transport Processes ◽  
Electrolyte Transport ◽  
Renal Diseases ◽  
Functional Studies ◽  
Renal Electrolyte Transport ◽  
Nephron Segment ◽  
Human Proteins ◽  
And Function ◽  
Rapid Emergence

Unique experimental advantages, such as its embryonic/larval transparency, high-throughput nature, and ease of genetic modification, underpin the rapid emergence of the zebrafish ( Danio rerio) as a preeminent model in biomedical research. Particularly in the field of nephrology, the zebrafish provides a promising model for studying the physiological implications of human solute transport processes along consecutive nephron segments. However, although the zebrafish might be considered a valuable model for numerous renal ion transport diseases and functional studies of many channels and transporters, not all human renal electrolyte transport mechanisms and human diseases can be modeled in the zebrafish. With this review, we explore the ontogeny of zebrafish renal ion transport, its nephron structure and function, and thereby demonstrate the clinical translational value of this model. By critical assessment of genomic and amino acid conservation of human proteins involved in renal ion handling (channels, transporters, and claudins), kidney and nephron segment conservation, and renal electrolyte transport physiology in the zebrafish, we provide researchers and nephrologists with an indication of the possibilities and considerations of the zebrafish as a model for human renal ion transport. Combined with advanced techniques envisioned for the future, implementation of the zebrafish might expand beyond unraveling pathophysiological mechanisms that underlie distinct genetic or environmentally, i.e., pharmacological and lifestyle, induced renal transport deficits. Specifically, the ease of drug administration and the exploitation of improved genetic approaches might argue for the adoption of the zebrafish as a model for preclinical personalized medicine for distinct renal diseases and renal electrolyte transport proteins.

A human colonic tumor cell line that maintains vectorial electrolyte transport

1984 ◽  
Vol 246 (2) ◽  
pp. G204-G208 ◽  
Author(s):  
K. Dharmsathaphorn ◽  
J. A. McRoberts ◽  
K. G. Mandel ◽  
L. D. Tisdale ◽  
H. Masui
Keyword(s):  
Cell Line ◽  
Basolateral Membrane ◽  
Tumor Cell Line ◽  
Transport Processes ◽  
Electrolyte Transport ◽  
Epithelial Cell Line ◽  
Culture Dish ◽  
Monolayer Cultures ◽  
Colonic Epithelial Cell Line ◽  
The Media

A human colonic epithelial cell line, T84, derived from a colonic carcinoma, has been examined both morphologically and functionally. The cells grew to confluence as a monolayer with the basolateral membrane attached to the surface of the culture dish and a microvillus-studded apical membrane facing the media. Tight junctions and desmosomes were demonstrated between adjacent cells. Confluent monolayer cultures conducted vectorial electrolyte transport that could be altered by a variety of secretagogues and antisecretagogues similar to isolated intestinal tissues. This cell line will serve as an excellent model system for the study of electrolyte transport processes and their regulation by peptide hormones and neurotransmitters.

Saturn's E, G and F rings: modulated by the plasma sheet

1984 ◽  
Vol 75 ◽  
pp. 597
Author(s):  
E. Grün ◽  
G.E. Morfill ◽  
T.V. Johnson ◽  
G.H. Schwehm
Keyword(s):  
Solar Wind ◽  
Direct Contact ◽  
Transport Processes ◽  
Time Variable ◽  
Dust Particles ◽  
Spatial Diffusion ◽  
Drag Forces ◽  
Orbit Perturbation ◽  
Time Variations ◽  
F Ring

ABSTRACTSaturn's broad E ring, the narrow G ring and the structured and apparently time variable F ring(s), contain many micron and sub-micron sized particles, which make up the “visible” component. These rings (or ring systems) are in direct contact with magnetospheric plasma. Fluctuations in the plasma density and/or mean energy, due to magnetospheric and solar wind processes, may induce stochastic charge variations on the dust particles, which in turn lead to an orbit perturbation and spatial diffusion. It is suggested that the extent of the E ring and the braided, kinky structure of certain portions of the F rings as well as possible time variations are a result of plasma induced electromagnetic perturbations and drag forces. The G ring, in this scenario, requires some form of shepherding and should be akin to the F ring in structure. Sputtering of micron-sized dust particles in the E ring by magnetospheric ions yields lifetimes of 102to 104years. This effect as well as the plasma induced transport processes require an active source for the E ring, probably Enceladus.

Early-Childhood Education for the Developmentally Delayed: Diagnosis, Intervention, and Evaluation

1979 ◽  
Vol 10 (2) ◽  
pp. 81-92
Author(s):  
Susan Freedman Gilbert
Keyword(s):  
Early Childhood ◽  
Early Childhood Education ◽  
School Children ◽  
Developmental Delays ◽  
Delayed Diagnosis ◽  
Language Impairments ◽  
Developmentally Delayed ◽  
Speech And Language ◽  
Childhood Education

This paper describes the referral, diagnostic, interventive, and evaluative procedures used in a self-contained, behaviorally oriented, noncategorical program for pre-school children with speech and language impairments and other developmental delays.

Sign in / Sign up

Export Citation Format

Share Document