Efficacy of Reductive Ventricular Osmotherapy in a Swine Model of Traumatic Brain Injury

BACKGROUND: The presence of osmotic gradients in the development of cerebral edema and the effectiveness of osmotherapy are well recognized. A modification of ventriculostomy catheters described in this paper provides a method of osmotherapy that is not currently available. The Reductive Ventricular Osmotherapy (RVOT) catheter removes free water from ventricular cerebrospinal fluid (CSF) by incorporating hollow fibers that remove water vapor, thereby providing osmotherapy without increasing osmotic load. OBJECTIVE: To increase osmolarity in the ventricular CSF through use of RVOT in vivo. METHODS: Twelve Yorkshire swine with contusional injury were randomized to external ventricular drainage (EVD) or RVOT for 12 hours. Magnetic resonance imaging was obtained. Serum, CSF, and brain ultrafiltrate were analyzed. Histology was compared using Fluor-Jade B and H & E. RESULTS: With RVOT, CSF osmolality increased from 292 ± 2.7 to 345 ± 8.0 mosmol/kg (mean ± SE, p=0.0006), and the apparent diffusion coefficient (ADC) in the injury region increased from 0.735 ±0 .047 to 1.135 ± .063 (p=0.004) over 24 hours. With EVD controls, CSF osmolarity and ADC were not significantly changed. Histologically, all RVOT pigs showed no evidence of neuronal degeneration (Grade 1/4) compared to moderate degeneration (Grade 2.6 +.4/4) seen in EVD treated animals (p=0.02). The difference in intracranial pressure (ICP) by area under the curve approached significance at p = .065 by Mann Whitney test. CONCLUSION: RVOT can increase CSF osmolarity in vivo after experimental traumatic brain injury (TBI). In anticipated clinical use, only a slight increase in CSF osmolarity may be required to reduce cerebral edema

Petromin: the slow death of statist oil development in Saudi Arabia

The paper recounts the history of Saudi Arabia's first national oil company, Petromin, which was originally supposed to take the place of foreign-owned Aramco. As a result of Petromin's inefficiency and personal rivalries among the Saudi elite, however, Petromin was progressively relegated to the sidelines in favour of a gradually 'Saudiised' Aramco. As a result, the organisation of the Saudi oil sector today is very different from - and more efficient than - that of most other oil exporters in the developing world. The paper concludes with a tentative taxonomy of national oil companies, based on the circumstances of nationalisation