Local cerebral glucose utilization in fetal and neonatal sheep

Abrams, Robert M.; Ito, Motohiro; Frisinger, J. E.; Patlak, C. S.; Pettigrew, Karen D.; Kennedy, C R

doi:10.1152/ajpregu.1984.246.4.r608

Cited by 35 publications

(22 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A more likely explanation for the simultaneous increase in blood pressure and brain BFV may therefore be a shift of the autoregulation range in the first week of life. The increase in middle cerebral artery BFV may also be a reflection of increasing metabolic demand (19)(20)(21). We cannot, however, exclude the possibility that the increase in middle cerebral artery Vmean is influenced by changes in vessel size as a result of increasing blood pressure (22).…”

Section: Discussionmentioning

confidence: 99%

Mesenteric Blood Flow Velocity and Its Relation to Circulatory Adaptation during the First Week of Life in Healthy Term Infants

et al. 1994

View full text Add to dashboard Cite

Science Center at Brooklyn, New York 11203 /A. C. Y. IWe investigated early postnatal changes of the mesenteric circulation and its relationship to the systemic circulation in two groups of newborn infants. Group I (n = 10) was studied before the first feeding at 1 h and preprandially at 6 and 24 h. Group I1 (n = 10) was studied before the first feeding at 2 h of age and preprandially and postprandially at d 3, 4, and 5. Blood flow velocity was measured with ultrasound Doppler in the superior mesenteric artery (SMA), middle cerebral artery, subclavian artery, and aortic orifice for cardiac output (CO) calculations. Blood pressure and heart rate were monitored. SMA mean velocity (Vmean) decreased from 1 [0.33 5 0.07 m/s (mean -c SD)] to 6 h (0.23 -c 0.08 m/s,p c 0.005) in group I, probably due to ductal steal, returning to the 1-h value at 24 h. In contrast, middle cerebral artery Vmean remained unchanged in the first 24 h. From d 3, SMA Vmean increased 92% postprandially, with no relation to increasing amounts of food. The postprandial increase in SMA Vmean was not associated with changes in CO and blood pressure; however, a fall in relative mesenteric vascular resistance suggested regional redistribution of CO. Middle cerebral artery Vmean increased from h 2 to d 3 with a further increase on d 4 (p < 0.01). This increase was associated with an increase in blood pressure. The relative fraction of CO to middle cerebral artery increased during the first days of life, suggesting a redistribution of blood flow to the metabolically active organs in the neonatal period. During the first days of life, the intestinal circulation must adapt to feeding and to changes occurring in the postnatal transitional circulation. Ultrasound imaging and Doppler techniques permit noninvasive studies of the circulatory adaptive changes during the early period after birth. Studies on superior mesenteric artery BFV by Van Be1 e t al.(1) showed that superior mesenteric artery BFV increased with gestational age and body weight, whereas Leidig (2) found an increasing fasting value after introduction of feeding and a definite postprandial increase.The objective of this study was to systematically investigate early postnatal changes of the mesenteric circulation as they relate to the overall hemodynamic adaptation in term infants. T o characterize these changes, we measured the mesenteric BFV from the first hours of life through the 5th d. We also examined changes in cardiac output, heart rate, blood pressure, and other regional circulations including that of a priority organ, the brain, and a secondary organ, the arm, during the first 5 d of life.The circulatory response to feeding was assessed from the 3rd to the 5th d of life. METHODSTwenty healthy term infants were included in the study. All infants were appropriate for gestational age and were born by normal vaginal delivery after uncomplicated pregnancies. The postnatal course was uneventful and the infants were all breast fed except for two infants who were formula fed on d 3.Because ...

show abstract

Section: Discussionmentioning

confidence: 99%

Mesenteric Blood Flow Velocity and Its Relation to Circulatory Adaptation during the First Week of Life in Healthy Term Infants

et al. 1994

View full text Add to dashboard Cite

show abstract

“…for the PET scan. The lumped constant (LC), used for correction between the difference in metabolism of deoxyglucose and glucose, is set to be 0.4 for fetal and neonatal lambs (Abrams et al, 1984). C* p (t)dt is the plasma concentration of FDG.…”

Section: Positron Emission Tomography Studymentioning

confidence: 99%

“…In the present study we chose the lumped constant (LC) 0.4, which has earlier been established for fetal and neonatal lambs (Abrams et al, 1984). There may be difference in the LC for ischemic tissue compared to the non-ischemic.…”

Section: Lumped Constant and Cmrglmentioning

confidence: 99%

Reduced postnatal cerebral glucose metabolism measured by PET after asphyxia in near term fetal lambs

Thorngren-Jerneck

Ley

Hellström‐Westas

et al. 2001

J of Neuroscience Research

View full text Add to dashboard Cite

The effects of fetal asphyxia on cerebral function and development, involve the transition from fetal to neonatal life. Changes in cerebral glucose metabolism may be an early postnatal indicator of fetal asphyxia. The objective is to develop an experimental lamb model involving the transition from fetal to neonatal life and to examine the effect of fetal asphyxia with cerebral hypoxic ischemia on early postnatal cerebral glucose metabolism. Fetal asphyxia was induced by total umbilical cord occlusion in eight near-term fetal lambs (134-138 days) with the ewe under isoflurane-opiate anesthesia. The mean occlusion time until cardiac arrest was 14.5 (4.2) min (SD). Lambs were immediately delivered and standardized resuscitation was instituted after 2 min asystole. At 4 hr postnatal age, [18-F]Fluoro-2-deoxy-glucose (18-FDG) was injected intravenously in eight asphyxiated lambs and in eight controls. Cerebral glucose metabolism was examined by positron emission tomography (PET). As a result the mean arterial blood pressure, acid-base values, blood glucose and serum lactate at 4 hr postnatal age did not differ significantly between lambs subjected to umbilical cord occlusion and controls. EEG was abnormal in all lambs subjected to cord occlusion and normal in the controls at 4 hr postnatal age. Global cerebral metabolic rate (CMRgl) as determined by PET was significantly lower in lambs subjected to cord occlusion mean/median (SD) 22.2/19.6 (8.4) micromol/min/100 g) than in controls mean/median (SD) 37.8/35.9 (6.1); P < 0.01). Global CMRgl is significantly reduced in newborn lambs 4 hr after fetal asphyxia induced by umbilical cord occlusion. A reduction in CMRgl is an early indicator of global hypoxic cerebral ischemia.

show abstract

“…They may be a direct consequence of altered substrate delivery to the fetal brain. The auditory pathway is metabolically very active in the fetal lamb during the gestational age range in which these growth-retarded related changes were observed (14). Cerebral blood flow is similar in normal and growth-retarded fetuses (1 5) but as circulating concentrations of glucose and amino acids are altered in growthretarded fetuses, substrate delivery to the brain is different, e.g.…”

Section: Discussionmentioning

confidence: 99%

Precocial Neural Function in the Growth-Retarded Fetal Lamb

et al. 1988

View full text Add to dashboard Cite

ABSTRACT. Clinical studies suggest that growth-retarded prematurely delivered infants are neurologically precocious. We investigated this paradoxical observation in the fetal lamb. Somatosensory and brainstem auditory-evoked potentials were studied in chronically instrumented fetal lambs in late gestation with varying degrees of growth retardation induced by preconception uterine carunclectomy. The components of the brainstem auditory-evoked response appeared earlier ( p < 0.05) in fetuses at least 2 SD less than the mean weight for gestational age (n = 5) compared to normal controls (n = 8) or carunclectomized fetuses of normal size (n = 7). Several waveforms of both the somatosensory (N20, PIN 30, and P200) and the brainstem auditory-evoked response (I, 111 Clinical studies in the neonate suggest that growth-retarded prematurely born infants are neurologically mature compared to normal sized prematures (1-4). Such infants with evidence of IUGR exhibit shortened brainstem conduction times for auditory stimuli as measured by the BAEP and greater tolerance of the BAEP to increasing stimulus rates (2, 4). The latter observation suggests greater maturation of synaptic function.These observations suggest that fetal neural maturation is directly affected by the consequences of placental insufficiency. Alternatively they might reflect either the effects of maternal disease such as hypertension or its therapy (2). A further possibility is that fetal development is not affected and that the apparent neural precocity reflects parturition-related events differing in growth retardation and leading to altered neural function in the neonate. Techniques for recording both the SEP and BAEP-evoked potentials in the instrumented fetal lamb in utero have been developed (5, 6) and demonstrate developmental changes in a number of characteristic properties of these evoked potentials in the normal-sized fetal lamb over the last 40 days of gestation. We used these indices to examine whether neural maturation is altered in the growth-retarded fetus in utero. MATERIALS AND METHODSThirteen pregnant Romney/Suffolk ewes underwent fetal surgery under sterile conditions. The ewes had, at least 6 wk before conception, undergone surgery to remove as many of the endometrial caruncles as possible. Sheep fetuses conceived in ewes after endometrial caruncle removal include a proportion that are acidemic and growth retarded (7,8). The fetuses, aged between 110 and 113 days at time of surgery, were instrumented for stimulation and recording of both the BAEP and the SEP as previously described (5, 6). Briefly the fetuses had a systemic arterial and venous catheter inserted (carotid or axillary); extradural electrodes were placed to record over the sensory and auditory cortices and to record the biparietal ECOG. A waterproofed earphone was placed over the external auditory monitors after dividing the pinnae that was then sewn over the earphone to hold it in place. Stimulatory electrodes for the SEP were sewn into the upper lip 1-2 cm lateral to the mi...

show abstract

Local cerebral glucose utilization in fetal and neonatal sheep

Cited by 35 publications

References 0 publications

Mesenteric Blood Flow Velocity and Its Relation to Circulatory Adaptation during the First Week of Life in Healthy Term Infants

Mesenteric Blood Flow Velocity and Its Relation to Circulatory Adaptation during the First Week of Life in Healthy Term Infants

Reduced postnatal cerebral glucose metabolism measured by PET after asphyxia in near term fetal lambs

Precocial Neural Function in the Growth-Retarded Fetal Lamb

Contact Info

Product

Resources

About