Measurement of cardiac output with and organ trapping of radioactive microspheres.

Archie, Joseph P.; Fixler, David E; Ullyot, Daniel J.; Hoffman, Julien I.E.; Utley, Joe R.; Carlson, Edwin L.

doi:10.1152/jappl.1973.35.1.148

Cited by 165 publications

(51 citation statements)

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“…At each study period, cardiac output and regional CBF were determined using the reference organ modification of the radiolabeled microsphere technique (14). Immediately prior to each flow determination, arterial and sagittal sinus blood samples were drawn and analyzed for pH, pC02, and p 0 2 using a Coming 165 blood gas analyzer (Coming, Medfield, MA), and for hemoglobin concentration and % oxygen saturation using an OSM 2 hemoximeter (Radiometer, Copenhagen, Denmark).…”

Section: Methodsmentioning

confidence: 99%

The Effect of Theophylline on Regional Cerebral Blood Flow Responses to Hypoxia in Newborn Piglets

McPhee

Maxwell

1987

Pediatr Res

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ABSTRACT. Theophylline attenuates cerebral hypoxic hyperemia in several adult models and this is thought to be due to receptor-mediated antagonism of adenosine, a proposed mediator of hypoxic hyperemia. This attenuation of hypoxic hyperemia reduces cerebral oxygen delivery and mav thus ieo~ardize cerebral oxidative metabolism. With these con~de~ations in mind, and because theophylline is widely used in neonatal medicine, the present study was designed to investigate the effect of theophylline on regional cerebral blood flow, cerebral oxygen delivery, and cerebral metabolic rate for oxygen during normoxia and hypoxia in the newborn piglet model. In 16 newborn piglets, regional cerebral blood flow (microspheres) increased 250-350% during hypoxia (Pa02 20-30 torr), while cerebral oxygen delivery and cerebral metabolic rate for oxygen were maintained at normoxic levels. Eight of these piglets were then given 10 mg/kg theophylline ethylenediamine intravenously and studies during normoxia and hypoxia were repeated; the remaining eight piglets served as time controls. Regional cerebral blood flow, cerebral oxygen delivery, and cerebral metabolic rate for oxygen during normoxia and hypoxia were not influenced by theophylline, despite plasma theophylline levels of 55-65 pmol/liter, and cerebrospinal fluid theophylline levels of 30-40 pmol/liter. These negative results are reassuring with respect to hypoxic cerebral blood flow control in theophylline-medicated infants. However, they do not support a role for adenosine as a mediator of cerebral hypoxic hyperemia in this model. (Pediatr Res 21: 573-578, 1987) Abbreviations CBF, cerebral blood flow COD, cerebral oxygen delivery CMR02, cerebral metabolic rate for oxygen MAP, mean arterial pressure SSP, sagittal sinus pressure CPP, cerebral perfusion pressure ANOVA, analysis of variance Theophylline is used widely in neonatal medicine, its uses include the treatment of apnea of prematurity (1, 2), the treatment of bronchopulmonary dysplasia (3), and the facilitation of weaning from mechanical ventilation (4-6). Several studies in adult models have shown that theophylline attenuates CBF re-

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Section: Methodsmentioning

confidence: 99%

The Effect of Theophylline on Regional Cerebral Blood Flow Responses to Hypoxia in Newborn Piglets

McPhee

Maxwell

1987

Pediatr Res

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“…) .urn in diameter and were labelled with either 113Sn, 46SC or 141Ce. With the ewe conscious and standing, a dose of micro spheres (approximately 15 million) was injected into the left ventricle while blood was being withdrawn from the abdominal aorta at approximately 25 ml min-1 (to provide the 'reference organ' for determination of the cardiac output) and from the left and right femoral vein catheters at approximately 15 ml min-1 during the time of injection of micro spheres and for 45 s after, to determine the percentage of the total flow passing through hind limb arteriovenous anastomoses (A VA's) (Archie et al 1973).…”

Section: Aficrosphere 1'echniquementioning

confidence: 99%

Measurement of Organ Blood Flow Using Tritiated Water. I. Hind Limb Muscle Blood Flow in Conscious Ewes

Oddy¹,

Brown²,

Jones³

1981

Aust. Jnl. Of Bio. Sci.

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Blood flow rates to a hind limb preparation, consisting predominantly of muscle, were obtained with tritiated water (TOR) diffusion and radioactive microsphere techniques in four conscious ewes (a total of seven comparisons).During the continuous infusion of TOR, equilibrium between muscle and its venous drainage was attained by 40-60 min after the start of the infusion. Total blood flow to the hind limb measured using TOR was corrected for arteriovenous anastomosis flow to provide a measure of capillary blood flow through the hind limb. The capillary blood flow rates so obtained using TOR were highly correlated with those measured directly in muscle with microspheres (ml min-I, r = 0·934; mll00 g-l min-" r = O· 886, P < O· 01, n = 7) and the corresponding mean flow values obtained with the two techniques (respectively, 104·6 ± 15·1 v. 106·5 ± 14· 9 ml min-1 and 7·2 ± O· 8 v. 7·3 ± O· 8 mll00 g-l min-' ) were not significantly different. There were substantial differences in the capillary blood flow rates for the individual muscles of the hind limb.

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“…Non-entrapment of microspheres in tumor capillaries, but not in normal capillaries, is a reasonable possibility in view of the previous reports of abnormally large capillary sinusoids in several experimental and naturally occurring tumor types (Folkman, 1976;Ide et al, 1939;lntaglietta et al, 1977lntaglietta et al, Vaupel, 1977. Moreover, a significant amount of non-entrapment has been reported when small-sized spheres were used to measure normal tissue flow rate (Archie et al, 1973;Marcus et al, 1976;Ring et al, 1962). Thus, by comparing the venous counts with the circulation to the tumorbearing leg first occluded and then unoccluded, one can determine whether the spheres used were too small for entrapment in a particular type of tumor.…”

Section: Discussionmentioning

confidence: 99%

Simple methods for determining the accuracy of tumor blood flow measurements using radioactive microspheres in rats

Chan

Babbs

Vetter

1983

Journal of Pharmacological Methods

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Two simple methods are presented that allow positive identification of the accuracy and precision of the microsphere technique and a quick verification of sphere entrapment in tumor vessels. A known flow of Ringer's solution from a motor-driven syringe is perfused through the rat's isolated systemic circulation from left ventricle to right atrium and collected in a funnel. Using this preparation, total blood flow in rats measured with radioactive microspheres injected into the left ventricle was 97% of actual flow. The coefficient of variation (standard deviation/mean) of the microsphere measurements was 0.22. In the same preparation, nonentrapment of microspheres in subcutaneous tumor nodules grown on a hind limb could be measured from the difference in counts collected in venous effluent before and after placement of a tourniquet proximal to the tumor. For example, in two types of transplantable carcinoma, we found non-entrapment of less than 0.1% of the injected microspheres. Such a shunt would correspond to less than 10% of microspheres entering a typical tumor nodule and, in turn, less than 10% underestimation of true flow to the tumor. These two techniques may be helpful to other investigators in testing the accuracy of microsphere methods in various small animal tumor models.

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Measurement of cardiac output with and organ trapping of radioactive microspheres.

Cited by 165 publications

References 0 publications

The Effect of Theophylline on Regional Cerebral Blood Flow Responses to Hypoxia in Newborn Piglets

The Effect of Theophylline on Regional Cerebral Blood Flow Responses to Hypoxia in Newborn Piglets

Measurement of Organ Blood Flow Using Tritiated Water. I. Hind Limb Muscle Blood Flow in Conscious Ewes

Simple methods for determining the accuracy of tumor blood flow measurements using radioactive microspheres in rats

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