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Lucia Schwyzer, Robert M. Starke, John A. Jane Jr. and Edward H. Oldfield

patients with acromegaly caused by GH-secreting tumors. We explored the possibility that if individual tumors have their own intrinsic level of GH production and if that level of GH production is homogeneous across the tumor, a comparison of GH levels before and after surgery would indicate the fraction of tumor that had been removed. Thus, a close correlation between tumor volume and hormone secretion in individual patients would permit calculation of the fraction of tumor removed by surgery, simply by measuring the postoperative GH levels. Methods We assessed

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P. Benjamin Kerr and Edward H. Oldfield

opened is limited by the size of the nose, which restricts the volume of the sellar exposure to <40% of the exposure achieved with a sublabial midline approach. 1 , 7 , 8 The endoscopic endonasal approach to the sella has recently increased in popularity. Some surgeons advocate excision of the middle turbinate to gain adequate exposure. 2 , 4 , 5 This seems counterproductive for a procedure, one of the commonly stated advantages of which is minimal tissue invasion. The sublabial-transnasal-transsphenoidal approach described here provides direct orientation to the

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John K. Ratliff and Edward H. Oldfield

and 350 g, were maintained on a 12-hour light/12-hour dark cycle and given free access to rodent food and water. Each experimental animal underwent surgical exposure and lesioning of the left sciatic nerve. Five adult primates (Macaca mulatta) were maintained in accordance with NIH animal care protocols. The primates underwent bilateral exposure and sectioning of peroneal and tibial divisions of the sciatic nerve. Infusion Apparatus and Infusate A gas-tight noncompliant delivery system that has no dead volume was previously described in a report on convective

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Gautam U. Mehta and Edward H. Oldfield

an intact sellar diaphragm, such leaks are unlikely to be a result of direct arachnoid puncture; however, their exact mechanism is not defined ( Fig. 1 ). F ig . 1. Drawings depicting the potential pathophysiology of CSF leaks from the superior margin of the pituitary gland during resection of intrasellar pituitary macroadenomas. A: Enlarged volume of sella contents leads to incompetence of the diaphragma sellae and exposed arachnoid. B: The combination of an incompetent diaphragma sellae and the downward force exerted on the gland during tumor

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Marsha J. Merrill and Edward H. Oldfield

intraventricularly 6 to 12 days before the insult, VEGF overexpression provides some protection against damage from transient ischemia. 8 Treating the surface of the brain with topical VEGF while a middle cerebral artery occlusion was being performed reduced cerebral damage, 61 including infarct volume, BBB disruption, and neuronal death. On the other hand, inhibiting VEGF induction after ischemia also has been reported to increase infarct size and neuronal damage. 183 In contrast, antagonizing VEGF action 30 minutes before ischemia reduced brain edema and spared cortical

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Paul F. Morrison, Russell R. Lonser and Edward H. Oldfield

-enhanced delivery permits a pressure-driven distribution of molecules directly within brain parenchyma via a cannula or catheter and can be used to target selected regions of the central nervous system (for example, deep brain nuclei) in a manner that bypasses the blood–brain barrier. Data from previous studies have also shown that CED can be used to distribute small and large molecules within the brain, brainstem, and spinal cord reliably, safely, and homogeneously over a wide range of volumes. 7 , 19 , 21–23 For macromolecules, the perfused tissue volume is related to the

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Davis G. Taylor, Panagiotis Mastorakos, John A. Jane Jr. and Edward H. Oldfield

I t has been recognized for many years that some patients with the Chiari I malformation have a congenitally reduced posterior fossa volume (PFV). Several radiographic analyses demonstrate, on average, reduced linear and volumetric measurements of the posterior fossa in patients with Chiari I malformation compared with controls. 1–3 , 10 , 18 , 28 The reduced size of the posterior fossa appears to be most significant at an early age and becomes less disproportionate with increasing age. 3 , 31 It has been postulated that in patients with a disproportionally

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Stereotaxic implantation of dispersed cell suspensions into brain

A systematic appraisal of cell placement and survival

Robert J. Plunkett, Richard J. Weber and Edward H. Oldfield

lobe was saved to assess possible spread of radioactivity into the contralateral hemisphere. The radioactivity in the control tubes, sponge, NaCl rinse, and each section of brain was measured. ‖ Recovery of radioactivity in the caudate nucleus was expressed as mean counts per minute (cpm) in the right frontal lobe/mean cpm in the three control tubes. Evaluation of Injection Techniques The techniques were perfected and the procedures were standardized during implantations in 15 rats. A baseline group of six animals then received implantations of 5 µ l volume

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Timothy C. Wirt, Zell A. McGee, Edward H. Oldfield and William F. Meacham

dose of amikacin was 0.3 mg/ml of estimated CSF volume. However, doses of 0.3 and 0.2 mg/ml of estimated CSF volume resulted in accumulation of amikacin, so that the dose finally adopted was 0.1 mg/ml of estimated CSF volume. Regardless of the dose, adjustments were made as indicated by the concentration of amikacin in the CSF just before the next 24-hour dose (the “trough level”). When administered through an Ommaya reservoir or external drain, injection of amikacin was followed by 2 ml of saline without preservative and then 2 ml of air to ensure full

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Russell R. Lonser, Malisa Sarntinoranont, Paul F. Morrison and Edward H. Oldfield

developed that account for water uptake in tissue 70 and tissue swelling with pressurization. 5 , 17 , 85 , 103 Tissue transport of the infused species is described by a differential mass balance relation governing tissue concentration as a function of space and time, which is formulated to account for convection, diffusion, metabolism, binding, and net transport across the microvasculature: ∂ C/∂ t = D∇ 2 C − ∇(vC/ f ) − k m C/ f − Ρ × s(C/ f − C p ), where k m is the first-order metabolic rate constant in tissue (the rate of degradation), f is the fluid volume