Changes in the Concentration of Potassium in the Erythrocytes and in Hæmoglobin Type in Merino Sheep under a Severe Anæmic Stress

Blunt, M.H.; Evans, J. V.

doi:10.1038/2001215b0

Cited by 67 publications

(12 citation statements)

References 6 publications

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“…The identity of the plasma factor which induces Hb C formation is not yet known; it is not present in plasma from nonanemic sheep, and its production is not dependent upon hemoglobin genotype. If the plasma factor turns out to be INTRODUCTION A change in the hemoglobin electrophoretic pattern occurs in sheep having the gene for hemoglobin (Hb) A when they become anemic (1)(2)(3)(4)(5). Van Vliet and Huisman (5) showed that Hb A is entirely replaced during severe anemia by a new hemoglobin type which they named Hb C. In heterozygous Hb AB sheep the relative proportion of Hb B remains constant during anemia; homozygous Hb B sheep do not show any change.…”

Section: Abstract This Investigation Is Concernedmentioning

confidence: 99%

Erythropoietic kinetics in sheep studied by means of induced changes in hemoglobin phenotype

Gabuzda¹,

Schuman²,

Silver³

et al. 1968

J. Clin. Invest.

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Section: Abstract This Investigation Is Concernedmentioning

confidence: 99%

Erythropoietic kinetics in sheep studied by means of induced changes in hemoglobin phenotype

Gabuzda¹,

Schuman²,

Silver³

et al. 1968

J. Clin. Invest.

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“…The switch from hemoglobin A to hemoglobin C which occurs in the erythropoietic response of certain sheep and goats which are anemic and/or hypoxic (4,7,24,41) has been shown to be inducible by erythropoietin (1, 6, 17, 23, 32, 39). These two hemoglobins are synthesized in the same cells and the control of this transition appears to be at the nuclear level, probably via transcription (3,18,33).…”

Section: Discussionmentioning

confidence: 99%

Effect of Hypoxia on Erythroblasts from Avian Fetal Liver: Adenosine Triphosphate Levels and Hemoglobin Synthesis

Schwartz

1976

Pediatr Res

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“…Startheterozygous. In those animals carrying the PA gene a third type ing on day 125 (n = 9) or 126 (n = 1) of gestation, synthetic of Hb (PC) is produced when sheep are made anemic (6,7). This ACTHI-24 was infused as a 15-min pulse (79 ng/min at the rate variant, linked to the PA gene differs from PA in having 141 of 1.9 ml/h) every 2 h into the jugular veins of chronically rather than 145 amino acids in the globin chain, and a minimum cannulated fetuses until spontaneous parturition or fetal death of 18 substitutions in amino acid structure (3,5).…”

Section: Abbreviations Materials and Methodsmentioning

confidence: 99%

Effect of Hormone-Induced Premature Parturition on Hemoglobin Switching in Sheep

et al. 1988

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ABSTRACT. This study examines the effect of premature delivery on the switch from fetal (a2 72) to adult (a2 @2) Hb, in lambs in which premature parturition was induced by the intrafetal infusion of ACTH or corticotropin releasing hormone. Of 10 chronically cannulated ovine fetuses given ACTH at the rate of 79 ng/min for a 15 min period every 2 h starting at days 125 (n = 9) or 126 (n = 1) of gestation, three died in utero at days 131, 131, and 130, respectively. The remaining seven were born alive at 133 2 1.6 days. Five control fetuses, treated with vehicle (0.9% NaCl, wtlvol) only were delivered at 149 f 2.7 days of gestation, which is not significantly different from the duration of pregnancy in other chronically cannulated lambs in this flock. Hb switching, as measured by the globin synthesis ratio, @/a, was complete at term in the control lambs. The @/a globin synthesis ratio of the prematurely delivered lambs was not accelerated by birth, and was similar to that of control fetuses of the same gestational age still in utero. The four lambs surviving premature birth more than 70 days did not complete the switch to normal adult Hb until after 220 days postconception. (Pediatr Res 24: 688-692, 1988) Hb disappears from neonatal blood (9). It was reported that in lambs carrying the PA gene a small proportion of PC (~1 5 % of total p) appears transiently after birth and persists for several months (10). Many attempts have been made to influence the time of onset of the switch from fetal (7) to adult (P) Hb but these have been largely unsuccessful (8,9,11,12). Once commenced, the rate of the switching process has been shown to be able to be modulated. Hypophysectomy or bilateral adrenalectomy of the chronically cannulated fetus causes the completion of the switch to be delayed considerably (8, 9). In the adrenalectomized fetus replacement of cortisol in gradually increasing amounts returned the rate of adult Hb synthesis to normal (9).An increase in fetal cortisol production precedes and indeed induces parturition at normal term in sheep (13). Premature parturition can be induced by the treatment of immature ovine fetuses with cortisol, ACTH, or CRF some 3 wk or more before normal term (14, 15). These fetuses show accelerated lung maturation. The purpose of this study was to investigate the effect of premature activation of the fetal adrenal on Hb switching in the ovine fetus. The hypothesis was that premature parturition, induced by the fetal infusion of ACTH or CRF, would accelerate the completion of the switch from fetal to adult Hb. Abbreviations MATERIALS AND METHODS CRH, corticotrophin-releasing hormoneA total of 54 blood samples (1 ml) from 20 fetuses chronically cannulated as described previously (16, 17) was used to establish a, p, and 7 globin synthesis in normal intact animals from 103 days of gestation until term. Then 39 samples were collected For most of gestation sheep fetal red blood cells contain a fetal from birth until 30 days postpartum, and three samples from Hb, with two a and two 7 globi...

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Changes in the Concentration of Potassium in the Erythrocytes and in Hæmoglobin Type in Merino Sheep under a Severe Anæmic Stress

Cited by 67 publications

References 6 publications

Erythropoietic kinetics in sheep studied by means of induced changes in hemoglobin phenotype

Erythropoietic kinetics in sheep studied by means of induced changes in hemoglobin phenotype

Effect of Hypoxia on Erythroblasts from Avian Fetal Liver: Adenosine Triphosphate Levels and Hemoglobin Synthesis

Effect of Hormone-Induced Premature Parturition on Hemoglobin Switching in Sheep

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