Serum-dependent transcellular active calcium transport

Moriarty, C. Michael

doi:10.1016/0014-4827(73)90491-6

Cited by 8 publications

(3 citation statements)

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“…Unfortunately the in vitro preparation is characterized by a rapid fall in its transepithelial potential difference, in its short circuit currents, and in its membrane resistance. This suggests 'tissue death' [Moriarty, 1973] and since this preparation also transports less calcium than normally occurs in ovo an attempt was made to develop an in vivo preparation which would enable the calcium transporting properties of this tissue to be studied under more physiological conditions. METHOD Fertile eggs of the domestic fowl (White Leghorn) were obtained from a local hatchery and used throughout this work.…”

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confidence: 99%

CALCIUM TRANSPORT BY THE CHICK CHORIOALLANTOIS IN VIVO

Crooks

Simkiss

1975

Exp Physiol

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A technique is described for attaching a perspex annulus to the chorioallantoic membrane of the chick embryo. Radioactive saline is placed on this membrane and the uptake measured in vivo. The method gives calcium influx values of 85-4 n mole/cm2/hr for 12-day and 115-9 n mole/cm2/hr for 15-day embryos. Efflux Leeson, 1963;Stewart and Terepka, 1969]. From then on relatively few changes occur in the morphology of the cells until the 18th day when the membrane begins to dry up prior to the hatching of the chick on day 21.The chorioallantoic membrane is involved in a remarkable number of ionic activities. On the allantoic side the pH of the embryonic urine changes from 7-5 to 5-5 on the 14th day of incubation [Walker, 1943;Abramovici, 1967]. This is followed by the movement of sodium and chloride ions and the rapid resorption of this fluid back into the embryo [Terepka, Stewart and Merkel, 1969]. The chorionic cells are also involved in the transport of sodium and chloride ions inwards [Moriarty and Hogben, 1970] and in addition they probably secrete acids or protons onto the eggshell [Crooks and Simkiss, 1974]. Perhaps the most remarkable property of the chorionic cells, however, is their ability to transport calcium ions from the eggshell into the circulation of the embryo. This phenomenon has been studied in vitro and shown to be an active process requiring oxidative phosphorylation [Garrison and Terepka, 1972a and b]. Unfortunately the in vitro preparation is characterized by a rapid fall in its transepithelial potential difference, in its short circuit currents, and in its membrane resistance. This suggests 'tissue death' [Moriarty, 1973] and since this preparation also transports less calcium than normally occurs in ovo an attempt was made to develop an in vivo preparation which would enable the calcium transporting properties of this tissue to be studied under more physiological conditions.

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confidence: 99%

CALCIUM TRANSPORT BY THE CHICK CHORIOALLANTOIS IN VIVO

Crooks

Simkiss

1975

Exp Physiol

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“…It is now well established that calcium can be actively taken up by the chorionic ectoderm (Terepka, Stewart & Merkel, 1969 ;Terepka, Coleman, Garrison & Spataro, 1971 ; Garrison & Terepka, 197za, b ; Moriarty, 1973;Crooks & Simkiss, 1975). The chorioallantois contains cells resembling oxyntic cells so that it is tempting to suggest that hydrogen ion secretion may be involved in the process of shell dissolution (Leeson & Leeson, 1963;Owczarzak, 1971;Coleman & Terepka, 1972;Narbaitz & Tellier, 1974).…”

Section: -2mentioning

confidence: 99%

Acid‐base Relationships Within the Avian Egg

Dawes

1975

Biological Reviews

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Summary 1. In the newly laid egg of the domestic fowl the pH values of the albumen and yolk are about 7.6 and 6.0 respectively. 2. When the egg is stored in air there is a loss of carbon dioxide from the albumen and the pH of this fluid rises to a maximum value of about 9.5. A large proportion of the carbon dioxide which remains in the albumen is in the form of carbonate. 3. In the fertile incubated egg the pH of the albumen attains a maximum value within a period of about 2 days; the albumen then becomes less alkaline and it is nearly neutral by the end of the second week. The increasing acidity of the albumen can be attributed to (a) the secretion of hydrogen ions by the blastoderm and (b) the output of carbon dioxide by developing tissues. 4. During the first 2 weeks of incubation the pH of the yolk progressively increases to a maximum value of about 7.5: there is then a tendency for the pH of this fluid to fall and the yolk that is retained within the body of the hatched chick is slightly acidic. 5. The embryo may never come into direct contact with either the albumen or the yolk when the pH of these fluids are high and low respectively. At the beginning of embryonic development the blastoderm is separated from the albumen by the vitelline membrane and from the yolk by a layer of subgerminal fluid with a maximum pH of about 7.8. The vitelline membrane ruptures on day 4 but by this time the embryo is bathed in amniotic fluid with a pH of about 7.5. 6. The pH of amniotic fluid falls from a maximum value of about 7.5 during week I to a minimum value of about 6.5 during week 2. Amniotic fluid is a simple solution of salts until day 12; albumen then begins to flow into the amniotic cavity and the buffering capacity of amniotic fluid increases. 7. The principal end‐product of nitrogenous metabolism in the chick embryo is uric acid and about 100 mg of this substance are deposited within the allantoic cavity. The pH of allantoic fluid may exceed 7.5 during week 1 but falls to 6.0 or below after day 13. 8. The tension of carbon dioxide within the egg is determined by the ratio of the rate of carbon dioxide production by the embryo to the permeability of the shell towards carbon dioxide. For the greater part of the period of incubation the permeability of the shell towards carbon dioxide is constant. Thus, as the carbon dioxide output of the embryo increases, the carbon dioxide tension within the egg rises. 9. The pH of the blood can be defined in terms of the ratio of the bicarbonate concentration to the carbon dioxide tension. There is a progressive increase in the carbon dioxide tension of the blood during the period of incubation but the pH is maintained at about 7.4 by an increase in bicarbonate concentration. 10. Part of the increase in bicarbonate is due to the removal of hydrogen ions from carbonic acid by haemoglobin. There is also a large influx of bicarbonate into the blood, but the source of this bicarbonate is not known; the evidence that renal mechanisms are involved is inconclusive and it is probable tha...

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“…The capillary plexus lies within the ectoderm. The ectoderm comes into close contact with the inner shell membrane at approximately 12 days of incubation, and transports the calcium from egg shell into the embryonic circulation (Moriarty and Terepka 1969;Terepka et al 1969;Coleman and Terepka 1972c;Garrison and Terepka 1972;Moriarty 1973). Three types of cell, the capillary-covering (CC) cell, villus-cavity (VC) cell and the regular undifferentiated (RU) cell (Narbaitz 1977;Packard and Packard 1984), form the ectoderm.…”

Section: Introductionmentioning

confidence: 99%

Ultrastructural localization of calcium in the chick chorioallantoic membrane as revealed by cytochemistry and X-ray microanalysis

1992

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The chorioallantoic membrane (CAM) of the chick embryo actively transports calcium from the egg shell into the embryonic circulation. To investigate the intracellular pathway of calcium transport across the CAM, ultrastructural localization of intracellular calcium in cells of the chorionic ectoderm (CE) was determined using cytochemical methods and X-ray microanalysis. Treatment of the CE with potassium oxalate, potassium ferricyanide or potassium pyroantimonate revealed large numbers of electron-dense granules (EDGs) in the ectodermal cells. These measure 30-40 nm in diameter, and are not membrane-bound. These granules were seen in all three cell types of the CE. The presence of calcium in the EDG was directly confirmed by X-ray microanalysis. When strontium or barium ions were applied to the shell membrane side of the CAM, the cells of the CE incorporated these divalent cations and sequestered them in granules (25-40 nm in diameter) in cytoplasm and mitochondria. This study indicates that calcium enters the CE cells by means other than endocytosis, as the EDGs are not membrane-bound, that all three types of the CE cells appear to function in transport of calcium from shell to embryo during embryogenesis, and that the EDG plays important roles in intracellular accumulation of calcium during the process of calcium transport across the chorioallantoic membrane.

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Serum-dependent transcellular active calcium transport

Cited by 8 publications

References 14 publications

CALCIUM TRANSPORT BY THE CHICK CHORIOALLANTOIS IN VIVO

CALCIUM TRANSPORT BY THE CHICK CHORIOALLANTOIS IN VIVO

Acid‐base Relationships Within the Avian Egg

Ultrastructural localization of calcium in the chick chorioallantoic membrane as revealed by cytochemistry and X-ray microanalysis

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