The Hemoglobin, Oxygen, Carbon Dioxide and Hydrogen Ion Concentrations in the Umbilical Bloods of Sheep and Goats as Sampled via Indwelling Plastic Catheters

Meschia, Giacomo; Barron, Donald H.; Cotter, Julian R.; Breathnach, C. S.

doi:10.1113/expphysiol.1965.sp001780

Cited by 143 publications

(68 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ewe was placed on her back and the Uterus exposed through a mid-line abdominal incision. The umbilical vessels were catheterised by COMLJNE and SILVER'S [2] modification of the method used by MESCHIA et al [28]. The cord was located by palpation through a 2-3 inch incision in the artero-median surface of the utedne wall, and small branches of one umbilical vein and an artery were cannulated with No.…”

Section: Methodsmentioning

confidence: 99%

Placental transfer and fetal uptake of amino acids in the pregnant ewe

Young¹,

Fadyen²

1973

Journal of Perinatal Medicine

View full text Add to dashboard Cite

Section: Methodsmentioning

confidence: 99%

Placental transfer and fetal uptake of amino acids in the pregnant ewe

Young¹,

Fadyen²

1973

Journal of Perinatal Medicine

View full text Add to dashboard Cite

“…Polyvinyl catheters (0.58 mm i.d.) were inserted in the main umbilical vessels from their peripheral branches in the two uterine horns according to techniques previously described (7,10). Satisfactory catheterization of both umbilical arteries and veins was achieved in 8 of 11 experiments.…”

Section: Methodsmentioning

confidence: 99%

Measurement of Umbilical Arterial Blood Flow to the Sheep Placenta and Fetus in Utero

Makowski

Meschia

Droegemueller

et al. 1968

Circulation Research

Self Cite

197

View full text Add to dashboard Cite

A method of estimating the magnitude and distribution of umbilical blood flow by means of radioactive microspheres in sheep fetuses in utero is described. Simultaneous measurements of total umbilical flow by this method and the steady-state diffusion technique showed agreement within ± 11%. In 11 fetuses of 90 to 150 days gestational age, the distribution of umbilical flow to the intercotyledonary chorion was 6.2 ± 0.8% of the total. This information has been used to estimate the effect of venous admixture of cotyledonary and noncotyledonary blood on the umbilical vein-uterine vein concentration difference of inert molecules with flow-limited transplacental clearance. ADDITIONAL KEY WORDSradioactive microspheres antipyrine regional blood flows shunted blood flow transplacental diffusion• Several methods of measuring umbilical blood flow of lamb fetuses have been described (1-6). Electromagnetic flowmeters placed in the common umbilical vein give a precise and continuous recording of umbilical blood flow, but the flows in such circumstances may be abnormal because the fetus is exteriorized and subjected to considerable surgical trauma. To avoid these disadvantages, methods of determining umbilical flow of the fetus within the uterine cavity have been developed. Accepted for publication September 9, 1968. is infused at a constant rate in a fetal vein until the transplacental diffusion rate of the test substance becomes constant. Umbilical flow can then be calculated as the ratio of the transplacental diffusion rate over the arteryto-vein difference of the test substance in the umbilical circulation. The validity of the calculated flow depends primarily on an accurate estimate of the transplacental diffusion rate and on the assumption that the umbilical vein sample is representative of total umbilical outflow. A comparison in the exteriorized fetus of the steady-state diffusion method with the cannulating electromagnetic flowmeter method has shown satisfactory agreement (7), but there has been no comparison of two independent intrauterine methods. The umbilical circulation of the sheep fetus is distributed to two structures: (1) the placental cotyledons and (2) the intercotyledonary chorion. In the cotyledons, maternal and fetal capillaries are in close apposition over a relatively large surface area, while in the intercotyledonary chorion the two capillary beds are separated by a greater

show abstract

“…Previous studies [5,6,10,11] have shown that stressful procedures have a significant effect on the physiologic state of the fetus. A steady state must be present at the time of sampling in order for a ratio of uptakes to be a meaningful metabolic parameter.…”

Section: Discussionmentioning

confidence: 99%

“…The catheters were brought through a subcutaneous tunnel to a flank patch as previously described [10]. The animals were standing and feeding within 6 hours of surgery.…”

Section: Surgerymentioning

confidence: 99%

“…Thus, despite the added technical difficulties of catheterizing the sagittal sinus rather than the deep facial vein, all animals studied in the chronic state had indwelling catheters placed in the brachiocephalic artery and the sagittal sinus. Since stressful procedures have been shown to alter significantly the physiologic state of the fetus [5,6,10,11], the animals were studied as chronic preparations which could be sampled for days after the acute stress of surgery.…”

Section: Experimental Designmentioning

confidence: 99%

See 1 more Smart Citation

Cerebral Glucose Utilization During Aerobic Metabolism in Fetal Sheep

et al. 1972

Self Cite

View full text Add to dashboard Cite

The relative utilization rates of glucose and oxygen by the fetal brain were evaluated by measuring simultaneously arteriovenous differences of glucose (A glucose) and oxygen (A oxygen) across the cerebral circulation of 10 fetal sheep. The mean db 1 SEM A glucose was 0.197 =b 0.012 HIM, and the A oxygen was 1.11 ± 0.08 HIM. Preductal arterial blood was obtained from the brachiocephalic artery; cerebral venous blood was obtained from the fetal sagittal sinus up to 6 days following surgery. A glucose/oxygen quotient was calculated to determine the fraction of cerebral oxygen consumption required to metabolize the glucose utilized by the brain to CO 2 and H 2 O. This quotient was 1.06 with 95% confidence limits of 1.12 and 1.02. These data indicate that glucose can supply all the aerobic metabolic requirements of the fetal brain. SpeculationAlthough glucose seems to be the primary substrate of cerebral metabolism, the amount of glucose acquired by the fetal lamb via the umbilical circulation can satisfy, at most, one-half of the total fetal aerobic needs. Thus the fetal brain seems much more dependent on glucose than do other fetal organs, and may be particularly vulnerable to periods of hypoglycemia.

show abstract

The Hemoglobin, Oxygen, Carbon Dioxide and Hydrogen Ion Concentrations in the Umbilical Bloods of Sheep and Goats as Sampled via Indwelling Plastic Catheters

Cited by 143 publications

References 5 publications

Placental transfer and fetal uptake of amino acids in the pregnant ewe

Placental transfer and fetal uptake of amino acids in the pregnant ewe

Measurement of Umbilical Arterial Blood Flow to the Sheep Placenta and Fetus in Utero

Cerebral Glucose Utilization During Aerobic Metabolism in Fetal Sheep

Contact Info

Product

Resources

About