A Device for Measuring Intracranial Pressure

Hoppenstein, R

doi:10.1016/s0140-6736(65)91668-5

Cited by 20 publications

(10 citation statements)

References 4 publications

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“…Available information suggests that the newborn is capable of secreting vasopressin at birth and that both the osmoreceptor and volume control systems are functional (3)(4)(5)(6). Data regarding fetal vasopressin physiology, however, are meager.…”

Section: Speculationmentioning

confidence: 99%

“…Mothers with eclampsia treated with betamethasone have increased antenatal mortality compared with controls (13); animal studies indicate that corticosteroids may compromise placental function (23) and also cause temporary inhibition of lung growth (5,11). In addition, glucocorticoid administration may be hccompanied by reduced cell numbers in the brain and by disturbances of myelination, synaptic growth, and locomotor ability (9,19).…”

Section: Speculationmentioning

confidence: 99%

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Arginine Vasopressin Response to an Osmotic Stimulus in the Fetal Sheep

et al. 1978

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Summary MATERIALS AND METHODSBaseline plasma osmolality (pOsm) and plasma arginiie vasopressin (pAVP) were measured in chronically catheterized fetal sheep. Mean baseline pAVP in fetuses from 101-120 days was 1.9 + 0.46 pU/ml (mean * SEM) with a pOsm of 293 rt 1.8 mOsm/kg. In fetuses of 121-141 days of gestation, mean pAVP was significantly lower, 0.77 0.19 pU/ml (P < 0.05), with a similar pOsm (293 2 1.9 mOsm/kg). The logarithmic baseline pAVP values were linearly correlated with pOsm for both groups. Hypertonic saline infusion resulted in a similar increase in the log pAVP corrected for the rise in pOsm in the 101-120-day fetuses and in 121-141-day fetuses. The slope of this response was similar to that of the steady state relationship. The data indicates that the fetal osmoreceptor system for control of arginine vasopressin secretion is fully functional in the last trimester of pregnancy. SpeculationThe fetal hypothalamic posterior pituitary system appears to show a relatively heightened response to increases in plasma osmolality during the last trimester of gestation. This may reflect the heightened hypothalamic activity postulated to explain the high circulating growth hormone levels at this time. The higher baseline plasma vasopressin levels in the younger fetuses would support this view. Alternatively, the augmented responsiveness may represent an adaptive response to the immaturity of the fetal kidney with respect to free water clearance or an adaptive response to some extrarenal function of the hormone on salt and water homeostasis in utero.Vasopressin secretion is regulated by two systems of r e c e p tors: the osmoreceptors located in or near the supraoptic nuclei in the hypothalamus and a series of volume receptors, including left atrial stretch receptors and carotid sinus and aortic arch baroreceptors. Available information suggests that the newborn is capable of secreting vasopressin at birth and that both the osmoreceptor and volume control systems are functional (3-6). Data regarding fetal vasopressin physiology, however, are meager. Vasopressin has been identified in the human fetal pituitary at 10-12 weeks of gestation (9, 12) and in the fetal pituitary of other mammalian species, including the guinea pig, sheep, and seal, during the last half of gestation (1,2,10,12,14). In addition, in the sheep and monkey, significant concentrations of circulating vasopressin have been detectable in fetal blood during the last half of gestation (1, 1 l ) , and increases in circulating levels have been evoked either by osmolar or volume (hemorrhage) stimuli (1, 11). However, little is known about the sensitivity and relative responsiveness of the fetal osmoreceptor control system. The present studies were designed to provide this information. 5Pregnant Columbia or Columbia-Suffolk ewes were obtained from a local source and the gestational age based on the induced ovulation technique (7). The animals were maintained in the vivarium and fasted 4 8 hr before surgery. The pregnant ewes were anesthetized using a m...

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Section: Speculationmentioning

confidence: 99%

Section: Speculationmentioning

confidence: 99%

Arginine Vasopressin Response to an Osmotic Stimulus in the Fetal Sheep

et al. 1978

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“…5,6 Subsequently, electrodes have been implanted utilizing a variety of techniques: via a laminectomy in the subarachnoid space 6 or between the two layers of the dura or in the epidural space either dorsal or ventral to the spinal cord. [7][8][9] Subsequently, less invasive percutaneous techniques were introduced. 10 Great advances in technology have also driven the popularity of the field.…”

Section: Introductionmentioning

confidence: 99%

Spinal Cord Stimulation: An Update

2008

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Summary:Spinal cord stimulation has been used in the treatment of many chronic pain disorders since 1967. In this update, the indications for spinal cord stimulation are reviewed with attention to recent publications. A focused review of the literature on abdominal and visceral pain syndromes is also provided. Furthermore, the technology has evolved from the use of monopolar electrodes to complex electrode arrays. Similarly, the power source has changed from a radio frequency-driven system to a rechargeable impulse generator. These topics are covered, along with a short discussion of implant technique. Finally, we include a review of complications of such therapy. SCS as a technology and therapy continues to evolve.

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“…More recent evidence developed with more sensitive bioassays or with radioimmunoassay methods has suggested that the newborn can secrete AVP under some circumstances. Plasma AVP levels are increased in cord blood after vaginal delivery (2,7,8), and urinary AVP increases after fluid restriction during the first 3 days of life (1). Also, cold exposure produces a water diuresis in the newborn presumably via inhibition of AVP secretion, although in these studies AVP was not measured directly (4).…”

Section: Discussionmentioning

confidence: 99%

“…However, it is known that was separated using a refrigerated centrifuge. One ml aliquots newborn infants respond to the stress of delivery (2,7,8) or were extracted with Bentonite as described by Skowsky et al (23) surgery (8,16) with significant elevations of plasma AVP. Fisher and stored at -20" until assayed for AVP.…”

Section: Log [Avp] -Log [Avp]2mentioning

confidence: 99%

Control of Vasopressin Secretion in the Newborn Lamb

et al. 1979

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Summaryrelative to the adult. The present studies were undertaken to characterize plasma AVP responses to phlebotomy, hypertonic The plasma sodium, osmolality, and arginine vasopressin (AVP) saline infusion, water loading, and fluid deprivation in the newresponses t~ phlebotomy, hypertonic water loading and born lamb and t~ relate these responses to those seen in adult fluid restriction were studied in 2-49 day old lambs. Phlebotomy ewes. of 10 and 20% of the lamb's estimated blood volume produced 37-and &fold increments in plasma AVP, without a concomitant change in plasma sodium or osmolality. The infusion of 10 mEq/ MATERIALS A N D METHODSkg sodium chloride produced a 12% rise in plasma sodium concentration accompanied by a 7-fold rise in plasma AVP. Water loading ANIMALS with 100 ml/kg hypotonic fluid Produced a significant fall in plasma Jugular vein and carotid artery catheters were inserted under sodium concentration (10.7%) and a decrease in plasma AVP.local anesthesia into 22 spontaneously delivered, full term, Eighteen hr of water deprivation evoked a 7-fold increase in AVP.healthy, (Columbia-Suflolk) lambs. A heparin solution was used These indicate that the newborn lamb is of to maintain patency of the catheters. The animals were allowed to responding appropriately to stimuli for secretion. The nurse ad libitum from the ewes. Each lamb was allowed at least 1 stimulus response ratio (SRR): recovery day after catheter placement before studv. Four studvprotocols were used to stimulate or suppress endogenous AVP SRR = A osmolality release; these included phlebotomy, hypertonic saline, fluid deprivation, and water loading. No animal participated in more than of newborn lambs was nearly identical after hypertonic saline and two studies; sequential studies were performed in random order. water loading and was also quite similar to that of the adult ewe Three ml base line blood samples were collected from the carotid after a saline challenge. The SRR of water deprived lambs was artery at -6 min, -3 min, and immediately before each challenge. greater than that after the other stimuli, presumably reflecting Phlebotomy was conducted in 10 lambs ranging in age from 1-combined volume and osmolar stimuli. We conclude that the 7 wk (mean = 26 days). After collection of baseline samples, as neurohypophysis and the volume receptor systems of the newborn above, 10 ml/kg of blood were removed over 1-2 min, after which lamb are capable of appropriate, mature AVP responsiveness 3 ml blood samples were obtained every 3 min for 15 min. A during the first days of extrauterine life. second 10 ml/kg phlebotomy was then performed and the sampling protocol repeated. Hypertonic saline stimulation was conSpeculation ducted in 11 lambs 2-35 days old (mean = 19 days). Base line The present studies indicate that AVP secretion in the newborn blood samples were collected as described, and hypertonic ~a c l sheep is responsive to both volume and osmolar stimuli. Quanti-(10 mEq/kg of a solution containing 4 mEq/ml) was injected over tat...

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A Device for Measuring Intracranial Pressure

Cited by 20 publications

References 4 publications

Arginine Vasopressin Response to an Osmotic Stimulus in the Fetal Sheep

Arginine Vasopressin Response to an Osmotic Stimulus in the Fetal Sheep

Spinal Cord Stimulation: An Update

Control of Vasopressin Secretion in the Newborn Lamb

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